WO2009058654A1 - Process for producing secondary alcohol alkoxy sulfates - Google Patents

Abstract

A process for making secondary alcohol alkoxy sulfates which comprises: (a) reacting carbon monoxide and hydrogen under Fischer-Tropsch conditions in the presence of a Fischer-Tropsch catalyst to produce a reaction mixture comprising paraffins, (b) contacting the paraffins with oxygen in the presence of an oxidation catalyst to produce secondary alcohols, (c) contacting the secondary alcohols with an alkylene oxide in the presence of a double metal cyanide catalyst to produce secondary alcohol alkoxylates, and (d) sulfating the secondary alcohol alkoxylates.

Description

PROCESS FOR PRODUCING SECONDARY ALCOHOL ALKOXY SULFATES

Field of the Invention

This invention relates to a process for producing secondary alcohol alkoxy sulfates from carbon monoxide and hydrogen . Background of the Invention

A large variety of products useful, for instance, as nonionic surfactants, wetting and emulsifying agents, solvents and chemical intermediates are prepared by the addition reaction (alkoxylation reaction) of alkylene oxides (epoxides) with organic compounds having one or more active hydrogen atoms. For example, particular mention may be made of the alcohol ethoxylates prepared by the reaction of ethylene oxide with aliphatic alcohols of 6 to 30 carbon atoms. Such ethoxylates, and to a lesser extent corresponding propoxylates and compounds containing mixed oxyethylene and oxypropylene groups, are widely employed as nonionic detergent components in cleaning and personal care formulations .

Sulfated alcohol alkoxylates have a wide variety of uses as well, especially as anionic surfactants. Sulfated higher secondary alcohol ethoxylates (SAES) offer comparable properties in bulk applications relative to anionics like linear alkyl benzene sulfonates and primary alcohol ethoxy sulfates, as well as methyl ester sulfonates. These materials may be used to produce household detergents including laundry powders, laundry liquids, dishwashing liquids and other household cleaners, as well as lubricants and personal care compositions and as surfactants for (dilute) surfactant flooding of oil wells and as surfactant components used in e.g. alkali, surfactants and polymer containing mixtures, suitable for enhanced oil recovery. One typical method of preparing alkoxylated alcohols is by hydroformylating an olefin into an oxo-alcohol, followed by alkoxylation of the resulting alcohol by reaction with a suitable alkylene oxide such as ethylene oxide or propylene oxide. When primary alcohol alkoxylates are made, this is a three step process because olefins have to be made either by oligomerization of ethylene (which tends to be relatively expensive) or by dehydrogenation of paraffins. Secondary alcohol alkoxylates may be made in a two step process because secondary alcohols may be produced directly from paraffins.

It would be desirable to provide a less complex process for preparing alkoxylated alcohols and alkoxylated alcohol sulfates. At the same time, it would be desirable to make use of feedstocks which are cheaper than ethylene. In particular, it would be desirable to make use of feedstocks derived from the "Fischer-Tropsch" hydrocarbon synthesis which involves the reaction of carbon monoxide and hydrogen ("synthesis gas") to produce hydrocarbons. The synthesis gas used in the Fischer-Tropsch hydrocarbon synthesis is derived from cheap, abundantly available natural gas or coal.

Secondary alcohols may be made directly from paraffins by oxidation using boric acid as a catalyst. Strictly speaking, the boron reagent is not a catalyst as it is consumed in the reaction. Its function is to protect the oxygenate (sec-alcohol) by reaction to give an oxidation- resistant borate ester. In the overall process including boric acid recycles the boric acid does act as a "catalyst" because its secondary function is to increase the oxidation rate .

Borate esters of the secondary alcohols are formed and may be separated from the paraffins by distillation when the carbon number (number of carbon atoms in the alcohol chain) of the alcohol is 14 or less. When the carbon number is 15 or more, the distillation temperature required is equal to or above the decomposition temperature of the borate ester and therefore conventional distillation techniques may not be effective. It would, however, be useful to be able to make secondary alcohols, secondary alcohol alkoxylates and secondary alcohol alkoxy sulfates with carbon numbers of 15 or more.

Furthermore it would be advantageous to devise a method which would allow direct ethoxylation of the secondary alcohol without formation of mixtures of residual secondary alcohols and secondary alcohol ethoxylates with a very wide ethoxylate distribution. The latter is due to the difference in reactivity between the secondary alcohol and the primary alcohol formed upon attaching the first ethyleneoxy unit to the alcohol using the generally employed basic ethoxylation catalysts such as potassium hydroxide.

In current industrial practice secondary alcohol ethoxylates are made by an expensive two step process. First, two to three ethyleneoxy units are added to the secondary alcohol using (Lewis) acid catalysts to make a primary hydroxyl-containing low molecular weight (low-mol) ethoxylate. Second, after removal of the acid catalyst (generally by neutralization) , the desired additional amount of ethyleneoxy units is reacted with the low-mol ethoxylate (predominantly a primary alcohol mixture) using a basic catalyst such as potassium hydroxide. This two step approach has the advantage that the inevitable by-product of the (Lewis) acid catalyzed ethoxylation, 1,4-dioxane, can be removed by efficient flashing or stripping after removal or by neutralization of the acid catalyst from the low-mol ethoxylate intermediate product before its conversion to the end-product with the desired level of ethoxylation. It would be desirable to develop a simple and cost- effective ethoxylation method which allows a one step ethoxylation without 1,4-dioxane formation and without the formation of an ethoxylate with a very wide ethoxylate distribution. U. S Patent No. 6,429,342 shows that double metal cyanide catalysts (DMC) may be useful in the ethoxylation of low molecular weight alcohols.

The oxidation of paraffins in the presence of boric acid derivatives leads to the formation of diols as one of the main by-products (see N. Kurata and K. Koshida, Hydrocarbon Processing, 1978, 57(1), 145-151 and N.J. Stevens and J. R. Livingston, Chem. Eng. Progress, 1968, 64(1) , 61-66) . Therefore one has to expect that only after very complete purification from these contaminating diols will secondary alcohols be suitable for ethoxylation using a DMC catalyst and that the cost of such purification may render the economics of the overall process unviable. It is also known that in the presence of contaminating diols or triols the required amount of DMC catalyst may be so high that it is no longer economically viable to leave it in the end-product, considering the levels of heavy metal, such as cobalt, which would then end up in the final product, e.g. a household detergent. Another hurdle for the application of the DMC catalyst is the presence of sodium hydroxide in the secondary alcohol, since this base has been used in the hydrolysis of the borate ester of the secondary alcohols. It is also known that water and basic contaminants, such as sodium hydroxide or potassium hydroxide, reduce or even impede the activity of the DMC catalyst and therefore these contaminants should be removed from the secondary alcohol as meticulously as possible via extraction and/or topping and tailing.

Sulfation of secondary alcohol ethoxylates, particularly those having a low average number of EO units, is another hurdle to be surpassed. An economically viable combined oxidation work-up and ethoxylation method has been developed herein which circumvents all the above-described hurdles . Summary of the Invention

This invention provides a process for making secondary alcohol alkoxy sulfates which comprises: (a) reacting carbon monoxide and hydrogen under Fischer-Tropsch conditions in the presence of a Fischer-Tropsch catalyst to produce a reaction mixture comprising paraffins, (b) contacting the paraffins with oxygen in the presence of an oxidation catalyst to produce secondary alcohols, (c) contacting the secondary alcohols with an alkylene oxide in the presence of a double metal cyanide catalyst to produce secondary alcohol alkoxylates, and (d) sulfating the secondary alcohol alkoxylates .

In an embodiment, the carbon number of the paraffins and secondary alcohols is 9 or more, preferably 9 to 30, and the oxidation catalyst may be a boric acid derivative, preferably dehydrated orthoboric acid or metaboric acid. Since the molecular weight of the borate esters of the secondary alcohols may be over three times higher than that of the unreacted paraffins, these components may be separated from the unreacted paraffins by application of conventional means such as vacuum distillation.

In another embodiment, the carbon number of the paraffins and secondary alcohols is 15 or more, preferably 15 to 30, and the oxidation catalyst may be a boric acid derivative, preferably metaboric acid. As above, the average molecular weight of the borate esters of the secondary alcohols may be more than three times higher than that of the unreacted paraffins, these components may be separated from the unreacted paraffins by separation techniques such as high-vacuum flashing or stripping, using a wiped film evaporator, solvent-solvent extraction or by application of membrane separation techniques, such as dialysis using a latex rubber membrane and heptane as the eluens .

In another embodiment the saponification of the borate ester is carried out with an aqueous base. Alternatively the hydrolysis step is replaced by transesterification with a low boiling alcohol, such as methanol or ethanol . In this case the low boiling trimethylborate or triethylborate may be easily boiled off from the secondary alcohol.

In another embodiment the ethoxylation is carried out in one single step using a double metal cyanide catalyst (DMC) in such low amounts that a secondary alcohol ethoxylate product is produced containing preferably less than 10 ppm cobalt metal and 20 ppm zinc metal.

In yet another embodiment the sulfation is carried out with sulfur trioxide pyridine complex. Brief Description of the Drawings

Fig. 1 is a graph which compares the secondary alcohol content as a function of time when a paraffin made according to the present invention is oxidized as opposed to when a paraffin from kerosene is oxidized. Detailed Description of the Invention

In step (a) of the present process hydrocarbons may be prepared by reacting carbon monoxide and hydrogen under suitable conditions. In general, the preparation of hydrocarbons from a mixture of carbon monoxide and hydrogen at elevated temperature and pressure in the presence of a suitable catalyst is known as the Fischer-Tropsch hydrocarbon synthesis. Catalysts used in this hydrocarbon synthesis are normally referred to as Fischer-Tropsch catalysts and usually comprise one or more metals from Groups 8, 9 and 10 of the Periodic Table of Elements, optionally together with one or more promoters, and a carrier material. In particular, iron, nickel, cobalt and ruthenium are well known catalytically active metals for such catalysts and can be used in the present process. Processes and catalysts for this reaction are described in U.S. Patent No. 7,105,706 which is herein incorporated by reference in its entirety.

The catalyst may preferably also comprise a porous carrier material, in particular a refractory oxide carrier. Examples of suitable refractory oxide carriers include alumina, silica, titania, zirconia or mixtures thereof, such as silica-alumina or physical mixtures such as silica and titania. Particularly suitable carriers are those comprising titania, zirconia or mixtures thereof.

In one embodiment of the present invention the catalyst is a cobalt-based Fischer-Tropsch catalyst. In the case of cobalt-based Fischer-Tropsch catalysts, titania carriers are preferred, in particular titania which has been prepared in the absence of sulfur-containing compounds. This carrier may further comprise up to about 50% by weight of another refractory oxide, typically silica or alumina. More preferably, the additional refractory oxide, if present, constitutes up to 20% by weight, even more preferably up to 10% by weight, of the carrier.

Typically, a cobalt-based Fischer-Tropsch catalyst comprises about 1-100 parts by weight of cobalt (calculated as element) , preferably about 3-60 parts by weight and more preferably about 5-40 parts by weight, per 100 parts by weight of carrier. These amounts of cobalt refer to the total amount of cobalt in elemental form and can be determined by known elemental analysis techniques.

In addition to cobalt the catalyst may comprise one or more promoters known to those skilled in the art. Suitable promoters include manganese, zirconium, titanium, ruthenium, platinum, vanadium, palladium and/or rhenium. The amount of promoter, if present, is typically between about 0.1 and about 150 parts by weight (calculated as element) , for example between about 0.25 and about 50, more suitably between about 0.5 and about 20 and even more suitably between about 0.5 and about 10, parts by weight per 100 parts by weight of carrier.

In another embodiment of the present invention the Fischer-Tropsch catalyst may be an iron-based Fischer-Tropsch catalyst. In particular, suitable iron-based Fischer-Tropsch catalysts include those disclosed in United States Patent 6,740,683 which is herein incorporated by reference in its entirety. Alternative iron-based Fischer-Tropsch catalysts include those used in the so-called "Synthol" process. Details of catalysts used in the Synthol process can be found in Frohning et al in Falbe; Chemical Feedstocks from Coal; Chapter 8; Fischer-Tropsch Process, pages 309-432, John Wiley & Sons, 1982. In particular, page 396 discloses details of Synthol catalyst preparation.

In the case of cobalt-based Fischer-Tropsch catalysts, the Fischer-Tropsch process conditions applied in step (a) of the present process may typically involve a temperature in the range from about 125 to about 350 ⁰C, or from about 150 to about 250 ⁰C, or from about 160 to about 230 ⁰C, and a pressure in the range from about 500 up to about 15,000 kPa abs, or from about 5500 to about 14,000 kPa abs . Step (a) of the present process may be operated at the pressures conventionally applied, i.e. up to about 8000 kPa abs., suitably up to about 6500 kPa abs.

In the case of an iron-based Fischer-Tropsch catalyst, in particular those catalysts disclosed in United States Patent 6,740,683, the Fischer-Tropsch process conditions applied in step (a) of the present process are preferably those as disclosed in United States Patent 6,740,683, about 200 to about 300 ⁰C and about 1000 to about 10,000 kPa abs .

Hydrogen and carbon monoxide (synthesis gas) may typically be fed to the reactor at a molar ratio in the range from about 0.5 to about 4, preferably from about 0.5 to about 3, more preferably from about 0.5 to about 2.5 and especially from about 1.0 to about 1.5. These molar ratios are preferred for the case of a fixed bed reactor.

The Fischer-Tropsch reaction step (a) may be conducted using a variety of reactor types and reaction regimes, for example a fixed bed regime, a slurry phase regime or a fluidized bed regime. It will be appreciated that the size of the catalyst particles may vary depending on the reaction regime they are intended for. It is within the normal skills of the skilled person to select the most appropriate catalyst particle size for a given reaction regime.

Further, it will be understood that the skilled person is capable to select the most appropriate conditions for a specific reactor configuration and reaction regime. For example, the preferred gas hourly space velocity may depend upon the type of reaction regime that is being applied. Thus, if it is desired to operate the hydrocarbon synthesis process with a fixed bed regime, preferably the gas hourly space velocity is chosen in the range from about 500 to about 2500 Nl/l/h (normal-litres/litre/hour,) . If it is desired to operate the hydrocarbon synthesis process with a slurry phase regime, preferably the gas hourly space velocity is chosen in the range from about 1500 to about 7500 Nl/l/h.

After carbon monoxide and hydrogen have reacted to produce a hydrocarbon fraction in step (a) , this hydrocarbon fraction may be hydrotreated and separated into one or more hydrocarbon fractions comprising from about 95 to about 100% by weight, preferably from about 99 to about 100% by weight, of paraffins . The separation may involve a distillation treatment. Conventional distillation techniques may be used. For example the separation step may involve fractional distillation, but the separation step may also comprise a combination of distillation with another separation treatment, such as condensation and/or extraction.

In one embodiment herein, the catalyst and process conditions in step (a) are selected such that the hydrocarbon fraction obtained in step (a) comprises a Ci₀ to Cn hydrocarbon fraction, a C_i2 to C_i3 hydrocarbon fraction or a combination of these two hydrocarbon fractions . The hydrocarbon fraction may contain from about 99 to about 100% by weight of paraffins. In another embodiment, the catalyst and process conditions are selected to produce a Ci₄ to Ci₅ and a Ci₆ to Ci₈ hydrocarbon fraction or a combination of these two hydrocarbon fractions.

As used herein, the term "hydrocarbon fraction" means a portion of the Fischer-Tropsch (FT) reaction product which boils within a certain temperature range. Said portion comprises a mixture of compounds synthesized in the Fischer- Tropsch reaction such as paraffins, olefins and alcohols. The compounds in a particular hydrocarbon fraction each have boiling points within the boiling point range for that hydrocarbon fraction .

The particular hydrocarbon fraction selected will depend on the desired end use of the secondary alcohol alkoxysulfates . Particularly suitable for use herein are hydrocarbon fractions which comprise paraffins and olefins having from 9 to 18 carbon atoms and hydrocarbon fractions having from 10 to 13 carbon atoms and hydrocarbon fractions having from 10 to 11 carbon atoms and hydrocarbon fractions having from 12 to 13 carbon atoms and hydrocarbon fractions having from 14 to 18 carbon atoms and hydrocarbon fractions having from 14 to 15 carbon atoms and hydrocarbon fractions having from 16 to 18 carbon atoms. Narrow cut fractions are particularly preferred because after oxidation of the paraffins, the separation between the secondary alcohols and the diols (by-product) is easier because there is no boiling point overlap.

Paraffins and olefins having the same number of carbon atoms, n, tend to have boiling points within about 5^°C or less of each other. Therefore hydrocarbon fractions can also be described in terms of the number of carbon atoms present in the paraffins and olefins contained therein. Hence a "C₉" hydrocarbon fraction will generally comprise paraffins having 9 carbon atoms and olefins having 9 carbon atoms . Suitable hydrocarbon fractions herein may be designated as "C₉", "Ci₀", "Cn", "Ci₂", "Ci₃", "Ci₄", "Ci₅", "Ci₆", "Ci₇" hydrocarbon fractions .

Other suitable hydrocarbon fractions may comprise a mixture of paraffins and olefins having a wider range of carbon atom numbers (and hence having a wider boiling point range) . For example, other such hydrocarbon fractions suitable for use herein include the C₈-Ci₀, Cn-Ci₂, Ci₃-Ci₄ and Ci₅-Ci₆ hydrocarbon fractions. To take an example, the Cn-Ci₂ hydrocarbon fraction will tend to comprise a mixture of paraffins and olefins having from 11-12 carbon atoms, in addition to alcohols having from 9-10 carbon atoms. However, the Cn-Ci₂ hydrocarbon fraction may additionally comprise paraffins, olefins and alcohols of higher or lower carbon number, depending on the boiling point range of the fraction.

These hydrocarbon fractions can be used individually as feed to oxidation step (b) , but two or more of these fractions may also be combined into a feed stream to the oxidation step (b) . The process of the present invention is particularly suitable when using Ci₀-Cn hydrocarbon streams, Ci₂-Ci₃ hydrocarbon streams, Ci₄-Ci₅ hydrocarbon streams and C₁6-C₁8 hydrocarbon streams or mixtures thereof. Narrow cut fractions particularly preferred because after oxidation of the paraffins, the separation between the secondary alcohols and the diols (by-product) is easier because there is no boiling point overlap.

The crude products from the FT reaction probably should not be used in the Bashkirov oxidation. Co-produced olefins are expected to have a negative effect on the selectivity and rate of the oxidation. Co-produced alcohols may be allowed because they may be separated from paraffins and olefins after borate ester formation by membrane separation. The crude FT products of a gas to liquids plant generally contain paraffins, (alpha) olefins and alcohols of high molecular weight as the main products. They are subsequently hydrogenated and/or (hydro) cracked to the desired saturation level and mol weight distribution. These saturated products are distilled. Paraffin Oxidation

The paraffins may be oxidized in the presence of a weak acid, preferably boric acid. Boric acid is preferred because it leads to high selectivity of alcohol formation and it catalyzes alcohol formation at a fast rate.

Boric acids which can be used in the present invention include orthoboric acid, metaboric acid (dehydrated boric acid), and boric oxide, as well as boric esters. Each of these boric acid forms will readily form esters with the secondary alcohols, whereas boric esters will transesterify with secondary alcohols.

This is important to prevent further oxidation of the secondary alcohols. Metaboric acid is preferred because it is easily formed from orthoboric acid by dehydration, its esters are more resistant to further oxidation and are easily hydrolyzed or transesterified, the concomitant boric acid or borate derivative may be efficiently recycled, and it is finely divided and has less tendency to agglomerate and deposit on the reactor walls . Metaboric acid may be formed from orthoboric acid by dehydration. Boric anhydride gives the least fouling due to being a high melting finely divided solid. Orthoboric and metaboric acids may be heated slowly in paraffin under N₂ to produce a non-fouling boron compound.

At least a portion of the feed paraffins may be mixed with boric acid to form a slurry. This slurry may then be dehydrated to form metaboric acid. The dehydration may take place at a temperature of from about 140 to about 160⁰C over a period of from about 0.1 to about 2 hours.

The dehydrated slurry of metaboric acid and paraffins and also the portion of the feed paraffins which was not mixed with the acid are introduced into an oxidation reactor. Oxidizing gas is also added to the reactor. The oxidizing gas may be air or an inert gas such as nitrogen with a low concentration of oxygen. The rate of oxidation may be controlled by limiting the amount of oxygen absorbed. This can be done by limiting the air flow, operating with air at reduced pressures to limit the amount of oxygen absorbed, or by using a gas with a low oxygen content. It is preferred to use an inert gas, such as nitrogen, with an oxygen content of from about 2 to about 8 volume percent.

The oxidation reaction may be carried out at a temperature from about 150 to 175°C. Above 175°C, the reaction is difficult to control. Preferred temperatures for use herein range from about 160 to about 175°C. The reaction is generally carried out at relatively low pressures. The pressure may range from about 100 to about 300 kPa abs .

The length of time of the oxidation has an effect on the conversion of the paraffins to the secondary alcohols. In order to obtain as high a yield as possible, the oxidation may continue for from about 2 to about 4 hours .

The reaction of the alcohols with the metaboric acid to form borate esters of the alcohols is reversible. Water may be removed during the oxidation to drive the reaction to produce more esters .

The oxidation reaction mixture is then distilled to remove unreacted paraffins and other low boiling compounds. The operating conditions will depend upon the carbon number of the feed paraffins and the borate esters produced. The paraffins may be recycled after being washed with caustic followed by water washing.

When the carbon number of the paraffins and secondary alcohols is 14 or less, the separation by distillation is straightforward. When the carbon number is 15 or more, the separation may be carried out by application of high vacuum flashing or stripping, using a wiped film evaporator or by application of membrane separation techniques, such as dialysis using a latex rubber membrane and heptane as the eluens .

The next step is hydrolysis of the borate esters to form alcohols and boric acid. Water is added to the borate ester mixture at elevated temperature, preferably of from about 90 to about 100⁰C over a period of from about 1 to about 3 hours. The alcohols may be separated by decantation of the aqueous boric acid phase. The boric acid in the aqueous phase may be crystallized out and recycled.

The hydrolysis of the borate esters forms crude alcohols which contain residual organic acids, boric acid, and organic esters. These are removed by saponification by reaction of this mixture with a base at a temperature of from about 90 to about 100⁰C for from about 1 to about 3 hours. The base may be caustic soda, sodium hydroxide, potassium hydroxide, etc. The mixture is allowed to settle and the base (aqueous) layer is removed. This may be repeated more than once. The remaining organic material may then be washed with water at a temperature of from about 80 to about 100⁰C to separate the alcohols. Multiple water washing steps may be used.

The water washed material may then be subjected to two distillations. One distillation removes the lower boiling components and the other distillation removes the higher boiling components. The final recovered product is a secondary alcohol.

Instead of hydrolysis, transesterification of the borate esters with volatile alcohols, such as methanol or ethanol, may be employed for liberating the higher alcohols from the borate ester. The volatile methyl or ethyl esters of boric acid are subsequently boiled off. Organic esters and acids contained in the crude secondary alcohols are removed by saponification and subsequent extraction and washing with water. The water washed material may then be subjected to two distillations (topping and tailing) . One distillation removes the lower boiling components and the other distillation removes the higher boiling components. The final recovered product is the secondary alcohol.

Alternatively, membrane separation techniques may be employed to separate the liberated secondary alcohol from trialkyl borate and to separate the secondary alcohol from its further contaminants .

Alkoxylation

In step (c) of the present invention, the secondary alcohol alkoxylates may be prepared by a process comprising reacting a secondary alcohol with an alkylene oxide in the presence of a multi, usually double, metal cyanide (DMC) catalyst . In terms of processing procedures, the alkoxylation reaction in the invention may be conducted in a generally conventional manner. For example, the catalyst may initially be mixed with liquid secondary alcohol. The mixture of catalyst and liquid secondary alcohol may be contacted, preferably under agitation, with alkylene oxide reactant, which is typically introduced in gaseous form, at least for the lower alkylene oxides. The order in which the reactants and catalyst are contacted has not been found to be critical to the invention.

While these procedures describe a batch mode of operation, the invention is equally applicable to a continuous process.

Overall, the two reactants are utilized in quantities which are predetermined to yield an alkoxylate product of the desired mean or average adduct number. The average adduct number of the product is not critical to this process. Such products commonly have an average adduct number in the range from less than one to 30 or greater. In one embodiment, the quantities are selected to produce an ethoxylate containing an average of 3 to 7 ethylene oxide (EO) groups per molecule of the ethoxylate.

In general terms, suitable and preferred process temperatures and pressures for purposes of this invention are the same as in conventional alkoxylation reactions between the same reactants, employing conventional catalysts. A temperature of at least about 90 ⁰C, particularly at least about 120 ⁰C and most particularly at least about 130 ⁰C, may be utilized to achieve sufficient rate of reaction, while a temperature of about 250 ⁰C or less, particularly about 210 ⁰C or less, and most particularly about 190 ⁰C or less, typically is desirable to minimize degradation of the product. As is known in the art, the process temperature can be optimized for given reactants, taking such factors into account .

Superatmospheric pressures, e.g., pressures between about 170 and about 1000 kPa abs, may be used as long as the pressure is sufficient to maintain the secondary alcohol substantially in the liquid state.

When the secondary alcohol is a liquid and the alkylene oxide reactant is a vapor, alkoxylation may then be suitably conducted by introducing alkylene oxide into a reactor containing the secondary alcohol and the catalyst. For considerations of process safety, the partial pressure of a lower alkylene oxide reactant is preferably limited, for instance, to about 400 kPa abs or less, and/or the reactant is preferably diluted with an inert gas such as nitrogen, for instance, to a vapor phase concentration of about 50 volume percent or less. The reaction may, however, be safely accomplished at greater alkylene oxide concentration, greater total pressure and greater partial pressure of alkylene oxide if suitable precautions, known in the art, are taken to manage the risks of explosion. A total pressure of from about 400 to about 900 kPa abs with an alkylene oxide partial pressure of from about 200 to about 500 kPa abs may be advantageously used.

The time required to complete this step of the process according to the invention is dependent both upon the degree of alkoxylation desired (i.e., upon the average alkylene oxide adduct number of the product) as well as upon the rate of the alkoxylation reaction (which is, in turn, dependent upon temperature, catalyst quantity and nature of the reactants) . A typical reaction time may be from about 1 to about 24 hours, preferably from about 1 to about 4 hours.

After the ethoxylation reaction has been completed, the product may be cooled. If desired, catalyst may be removed from the final product, although catalyst removal is not necessary to the process of the invention. Catalyst residues may be removed, for example, by filtration, precipitation, or extraction. A number of specific chemical and physical treatment methods have been found to facilitate removal of catalyst residues from a liquid product. Such treatments include contact of the alkoxylation product with strong acids such as phosphoric and/or oxalic acids or with solid organic acids such as NAFION H+ or AMBERLITE IR 120H acids; contact with alkali metal carbonates and bicarbonates; contact with zeolites such as Type Y zeolite or mordenite; or contact with certain clays. Typically, such treatments are followed by filtration or precipitation of the solids from the product. In many cases filtration, precipitation, or centrifugation is most efficient at elevated temperature.

For reasons of both process performance and commercial value of the product, secondary alcohols (and their alkoxylates and alkoxysulfates) having from 9 to 30 carbon atoms, with C9 to C24 secondary alcohols considered more preferred and C9 to C20 C_]_Q to C]_3 and C]_4 to C]_g secondary alcohols considered highly preferred and C]_i to C]_3 C]_4 to C16 ^15 to C]_7 and C]_g to C]_g secondary alcohols considered most preferred, including mixtures thereof, such as a mixture of C9 and C20 secondary alcohols. As a general rule, the secondary alcohols may be of branched or straight chain structure depending on the intended use. In one embodiment, preference further exists for secondary alcohols reactants in which greater than 50 percent, more preferably greater than 60 percent and most preferably greater than 70 percent of the molecules are of linear (straight chain) carbon structure. In another embodiment, preference further exists for secondary alcohols reactants in which greater than 50 percent, more preferably greater than 60 percent and most preferably greater than 70 percent of the molecules are of branched carbon structure.

Examples of secondary alcohols which may be made herein include 2-undecanol, 2-hexanol, 3-hexanol, 2-heptanol, 3- heptanol, 2-octanol, 3-octanol, 2-nonanol, 2-decanol, 4- decanol, 2-dodecanol, 2-tetradecanol, 2-hexadecanol, and mixtures thereof.

Suitable alkylene oxide reactants for use herein include an alkylene oxide (epoxide) reactant which comprises one or more vicinal alkylene oxides, particularly the lower alkylene oxides and more particularly those in the C2 to C4 range. In general, the alkylene oxides are represented by formula (I)

wherein each of the R^, R^, R^ and R^ moieties is individually selected from the group consisting of hydrogen and alkyl moieties. Reactants which comprise ethylene oxide, propylene oxide, butylene oxide, or mixtures thereof are more preferred, particularly those which consist essentially of ethylene oxide and propylene oxide. Alkylene oxide reactants consisting essentially of ethylene oxide are considered most preferred from the standpoint of commercial opportunities for the practice of alkoxylation processes, and also from the standpoint of the preparation of products having narrow-range ethylene oxide adduct distributions.

The catalyst used for the preparation of the alkoxylate composition of the present invention is a double metal cyanide catalyst. Any double metal cyanide catalyst suitable for use in alkoxylation reactions can be used in the present invention. Conventional DMC catalysts are prepared by reacting aqueous solutions of metal salts and metal cyanide salts or metal cyanide complex acids to form a precipitate of the DMC compound.

The DMC catalysts used herein are particularly suitable for the direct ethoxylation of secondary alcohols. It is particularly useful to be able to directly ethoxylate secondary alcohols since secondary alcohols may be derived from relatively cheap feedstocks such as paraffins produced by oxidation using Fischer-Tropsch technologies as described above .

The catalyst may be used in an amount which is effective to catalyze the alkoxylation reaction. The catalyst may be used at a level such that the level of solid DMC catalyst remaining in the final alkoxylate composition is in the range from about 1 to about 1000 ppm (wt/wt) , preferably of from about 5 to about 200 ppm (wt/wt) , more preferably from about 10 to about 100 ppm (wt/wt) . The DMC catalysts used in the present invention are very active and hence exhibit high alkoxylation rates. They are sufficiently active to allow their use at very low concentrations of the solid catalyst content in the final alkoxylation product composition. At such low concentrations, the catalyst can often be left in the alkoxylated alcohol composition without an adverse effect on product quality. The ability to leave catalysts in the alkoxylated alcohol composition is an important advantage because commercial alkoxylated alcohols currently require a catalyst removal step. The concentration of the residual cobalt in the final alkoxylate composition is preferably below about 10 ppm (wt/wt) .

Suitable metal salts and metal cyanide salts are, for instance, described in U.S. Patents Nos . 5,627,122 and 5,780,584, which are herein incorporated by reference in their entirety. Thus, suitable metal salts may be water- soluble salts suitably having the formula M(X' )_n', in which M is selected from the group consisting of Zn(II), Fe(II), Ni(II), Mn(II), Co(II), Sn(II), Pb(II), Fe(III), Mo(IV), Mo(VI), Al(III), V(V), V(IV) , Sr(II) , W(IV), W(VI), Cu(II), and Cr(III) . More preferably, M is selected from the group consisting of Zn(II) , Fe(II) , Co(II) , and Ni(II) , especially Zn(II) . In the formula, X' is preferably an anion selected from the group consisting of halide, hydroxide, sulfate, carbonate, cyanide, oxalate, thiocyanate, isocyanate, isothiocyanate, carboxylate, and nitrate. The value of n' satisfies the valency state of M and typically is from 1 to 3. Examples of suitable metal salts include, but are not limited to, zinc chloride, zinc bromide, zinc acetate, zinc acetonylacetate, zinc benzoate, zinc nitrate, iron (II) chloride, iron (II) sulfate, iron (II) bromide, cobalt (II) chloride, cobalt (II) thiocyanate, nickel (II) formate, nickel (II) nitrate, and the like, and mixtures thereof. Zinc halides, and particularly zinc chloride, are preferred. In one embodiment, the metal cyanide salt may be a water-soluble metal cyanide salt having the general formula (Y)_aιM' (CN)J₃I (A' )_QI in which M' is selected from the group consisting of Fe(II) , Fe(III), Co(II), Co(III), Cr(II), Cr(III), Mn(II), Mn(III) , Ir(III), Ni(II), Rh(III), Ru(II), V(IV), and V(V) . More preferably, M' is selected from the group consisting of Co(II), Co(III), Fe(II), Fe(III) , Cr(III), Ir(III) , and Ni(II) , especially Co(II) or Co(III) . The water-soluble metal cyanide salt may contain one or more of these metals. In the formula, Y is an alkali metal ion or alkaline earth metal ion, such as lithium, sodium, potassium and calcium. A' is an anion selected from the group consisting of halide, hydroxide, sulfate, carbonate, cyanide, oxalate, thiocyanate, isocyanate, isothiocyanate, carboxylate, and nitrate. Both a' and b' are integers greater than or equal to 1; c' can be O or an integer; the sum of the charges of a', b', and c' balances the charge of M' . Suitable water-soluble metal cyanide salts may include, for example, potassium hexacyanocobaltate (III) , potassium hexacyanoferrate (II) , potassium hexacyanoferrate (III ) , calcium hexacyanocobaltate (III) and lithium hexacyano- iridate(III) . A particularly preferred water-soluble metal cyanide salt for use herein is potassium hexacyanocobaltate (III) .

DMC catalysts useful in the process of this invention may be prepared according to the processes described in U.S. Published Patent application No. 2005/0014979, which is herein incorporated by reference in its entirely.

DMC catalysts may be prepared in the presence of a low molecular weight organic complexing agent such that a dispersion is formed comprising a solid DMC complex in an aqueous medium. The organic complexing agent used should generally be reasonably to well soluble in water. Suitable complexing agents are, for instance, disclosed in U.S. Patent No. 5,158,922, which is herein incorporated by reference in its entirely, and in general are water-soluble heteroatom- containing organic compounds that can complex with the double metal cyanide compound. Thus, suitable complexing agents may include alcohols, aldehydes, ketones, ethers, esters, amides, ureas, nitriles, sulfides, and mixtures thereof.

Combining both aqueous reactant streams may be conducted by conventional mixing techniques including mechanical stirring and ultrasonic mixing. Although applicable, it is not required that intimate mixing techniques like high shear stirring or homogenization are used. The reaction between metal salt and metal cyanide salt may be carried out at a pressure of from about 50 to about 1000 kPa abs and a temperature of from about 0 to about 80 ⁰C. However, it is preferred that the reaction be carried out at mild conditions, i.e. a pressure of about 50 to about 200 kPa abs and a temperature of from about 10 to about 40⁰C.

After the reaction has taken place and a DMC compound has been formed an extracting liquid may be added to the dispersion of solid DMC complex in aqueous medium, in order that the DMC catalyst particles may be efficiently and easily separated from the aqueous phase without losing any catalytic activity .

Suitable extracting liquids are described in U.S. Patent No. 6,699,961, which is herein incorporated by reference in its entirely. A suitable extracting liquid should meet two requirements: firstly it should be essentially insoluble in water and secondly it must be capable of extracting the DMC complex from the aqueous phase. The extracting liquid can, for instance, be an ester, a ketone, an ether, a diester, an alcohol, a di-alcohol, a (di)alkyl carbamate, a nitrile or an alkane. An especially preferred extracting liquid for use herein is methyl tert-butyl ether.

Typically the extracting liquid is added under stirring and stirring is continued until the liquid has been uniformly distributed through the reaction mixture. After the stirring has stopped the reaction mixture is allowed sufficient time to settle, i.e. sufficient time to separate into two phases: an aqueous bottom layer and a layer floating thereon containing the DMC catalyst dispersed in the extracting liquid.

The next part of the catalyst preparation process is for the aqueous layer to be removed. Since the aqueous layer forms the bottom layer of the two phase system formed, this may be easily accomplished by draining the aqueous layer via a valve in the bottom part of the vessel in which the phase separation occurred. After removal of the aqueous phase, the remaining phase contains the solid DMC catalyst particles which are dispersed or finely divided in the extracting compound and which are subsequently recovered.

The catalyst recovery step may be carried out in various ways . The recovery procedure may involve mixing the DMC catalyst with complexing agent, optionally in admixture with water, and separating DMC catalyst and complexing agent/water again, e.g. by filtration, centrifugation/decantation or flashing. This procedure may be repeated one or more times. Eventually, the catalyst may be dried and recovered as a solid. The recovery step may comprise adding a water/complexing agent to the DMC catalyst layer and admixing catalyst layer and water/complexing agent (e.g. by stirring) , allowing a two phase system to be formed and removing the aqueous layer. This procedure may be repeated one to five times after which the remaining catalyst layer may be dried and the catalyst may be recovered in solid form (as a powder) or, alternatively, a liquid alcohol/polyol may be added to the catalyst layer and a catalyst suspension in liquid alcohol is formed, which may be used as such.

The alcohol/polyol added may be any liquid alcohol/polyol which is suitable to serve as a liquid medium for the DMC catalyst particles. When the DMC catalyst is used for catalyzing the alkoxylation reaction of alcohols, it is preferred to use an alcohol/polyol which is compatible with the alkoxylated alcohols to be produced and which will not have any negative effect on the final alkoxylated alcohol produced when present therein in trace amounts . Examples of suitable polyols include polyols such as polyethylene glycol and polypropylene glycol.

The organic complexing agent may be removed from the catalyst slurry. This may be achieved by any means known in the art to be suitable for liquid-liquid separation. A preferred method for the purpose of the present invention is flashing off the complexing agent at atmospheric conditions or under reduced pressure. Flashing under reduced pressure is preferred, because this enables separation at a lower temperature which reduces the risk of thermal decomposition of the DMC catalyst.

The DMC catalyst may be recovered as a slurry in liquid alcohol/polyol . The advantage of such a slurry is that it is storage stable and may, for instance, be stored in a drum. Moreover, dosing of the catalyst and its distribution through the alkoxylation medium is greatly facilitated by using a catalyst slurry.

Sulfation

The secondary alcohol alkoxylates may be sulfated using one of a number of sulfating agents including sulfur trioxide, complexes of sulfur trioxide with (Lewis) bases , such as the sulfur trioxide pyridine complex and the sulfur trioxide trimethylamine complex, chlorosulfonic acid and sulfamic acid. The sulfation may be carried out at a temperature preferably not above about 80⁰C. The sulfation may be carried out at temperature as low as about -20⁰C, but higher temperatures are more economical. For example, the sulfation may be carried out at a temperature from about 20 to about 70⁰C, preferably from about 20 to about 60⁰C, and more preferably from about 20 to about 50⁰C. Sulfur trioxide is the most economical sulfating agent.

The secondary alcohol alkoxylates may be reacted with a gas mixture which in addition to at least one inert gas contains from about 1 to about 8 percent by volume, relative to the gas mixture, of gaseous sulfur trioxide, preferably from about 1.5 to about 5 percent volume. In principle, it is possible to use gas mixtures having less than 1 percent by volume of sulfur trioxide but the space-time yield is then decreased unnecessarily. Inert gas mixtures having more than 8 percent by volume of sulfur trioxide in general may lead to difficulties due to uneven sulfation, lack of consistent temperature and increasing formation of undesired byproducts . Although other inert gases are also suitable, air or nitrogen are preferred, as a rule because of easy availability.

The reaction of the secondary alcohol alkoxylate with the sulfur trioxide containing inert gas may be carried out in falling film reactors . Such reactors utilize a liquid film trickling in a thin layer on a cooled wall which is brought into contact in a continuous current with the gas. Kettle cascades, for example, would be suitable as possible reactors. Other reactors include stirred tank reactors, which may be employed if the sulfation is carried out using sulfamic acid or a complex of sulfur trioxide and a (Lewis) base, such as the sulfur trioxide pyridine complex or the sulfur trioxide trimethylamine complex. These sulfation agents would allow an increased residence time of sulfation without the risk of ethoxylate chain degradation and olefin elimination by (Lewis) acid catalysis.

The molar ratio of sulfur trioxide to alkoxylate may be 1.4 to 1 or less including about 0.8 to about 1 mole of sulfur trioxide used per mole of OH groups in the alkoxylate and latter ratio is preferred. Sulfur trioxide may be used to sulfate the alkoxylates and the temperature may range from about -20 ⁰C to about 50 ⁰C, preferably from about 5 ⁰C to about 40 ⁰C, and the pressure may be in the range from about 100 to about 500 kPa abs . The reaction may be carried out continuously or discontinuously . The residence time for sulfation may range from about 0.5 seconds to about 10 hours, but is preferably from 0.5 seconds to 20 minutes.

The sulfation may be carried out using chlorosulfonic acid at a temperature from about -20 ⁰C to about 50 ⁰C, preferably from about 0 ⁰C to about 30 ⁰C. The mole ratio between the alkoxylate and the chlorosulfonic acid may range from about 1:0.8 to about 1:1.2, preferably about 1:0.8 to 1:1. The reaction may be carried out continuously or discontinuously for a time between fractions of seconds (i.e., 0.5 seconds) to about 20 minutes.

Unless they are only used to generate gaseous sulfur trioxide to be used in sulfation, the use of sulfuric acid and oleum should be omitted. Subjecting any ethoxylate to these reagents leads to ether bond breaking - expulsion of 1,4-dioxane (back-biting) - and finally conversion of secondary alcohol to an internal olefin.

In primary alcohol ethoxy sulfate production the neutralization of the half-ester of sulfuric acid should be done as swiftly as possible, since otherwise elimination of sulfur trioxide will occur. This may lead to ethoxylate chain degradation with concomitant formation of 1,4-dioxane and shorter chain ethoxylates or finally primary alcohols or olefins, depending on the reaction conditions. In the case of secondary alcohol ethoxylates, and particularly those with a low average number of EO units, i.e. the low mol secondary alcohol ethoxylates of this invention, an excess of the Lewis acid sulfur trioxide should be avoided at all times since otherwise internal olefins, 1,4-dioxane, sulfur trioxide or sulfuric acid will become important by-products, depending on the reaction conditions. This prerequisite is anticipated to limit the sulfation conversion level of secondary alcohol ethoxylates or an alternative to this problem inherent to the sulfation of low-mol secondary alcohol ethoxylates under (Lewis) acid conditions has to be identified.

Following sulfation, the liquid reaction mixture may be neutralized using an aqueous alkali metal hydroxide, such as sodium hydroxide or potassium hydroxide, an aqueous alkaline earth metal hydroxide, such as magnesium hydroxide or calcium hydroxide, or bases such as ammonium hydroxide, substituted ammonium hydroxide, sodium carbonate or potassium hydrogen carbonate. The neutralization procedure may be carried out over a wide range of temperatures and pressures. For example, the neutralization procedure may be carried out at a temperature from about 0⁰C to about 65°C and a pressure in the range from about 100 to about 200 kPa abs . The neutralization time may be in the range from about 0.5 hours to about 1 hour but shorter and longer times may be used where appropriate.

EXAMPLES Example 1 Example IA: Oxidation of Light Detergent Feedstock (LDF)

The oxidation was performed in a 2-litre glass reactor equipped with a double turbine stirrer, overhead cooler, thermostat bath (Julabo F30) , and a safety relief valve of 500 kPa abs. The inlet gas flows were measured by mass flow controllers (Brooks Instruments, 5850TR) , and controlled by constant pressure valves (Testcom 500) and safety relief valves. The off-gas flow was controlled by a backpressure valve and measured by a gas meter (Ritter TG3) . The off-gas line was connected to a cold-trap and oxygen analyzer (M&C, PMA 225) . The maximum operating window of this unit was 500 kPa abs at 180 ⁰C.

The reactor was charged with 1200 ml (888.2g) Ci₀-Ci₃ paraffin (GC analysis gives typically 11 wt% decane, 32 wt% undecane, 31 wt% dodecane and 25 wt% tridecane, of which approximately 5 wt% are predominantly methyl-branched C₁0-C₁3 paraffins; GC x GC analysis: 250 mg/kg total mono-naphthenes, 10 mg/kg total di-naphthenes and 0 mg/kg total mono-aromatics) and 32.23 g B₂O₃ (Sigma-Aldrich, 99.98%) . Subsequently, the reactor was flushed with a N₂ flow (100 normal-liters/hour = 100 Nl/hr) until the O₂ concentration reached zero, while stirred (400 rpm) . The reactor was heated under a reduced N₂ flow. At 110 ⁰C it was pressurized to 150 kPa abs by increasing the N₂ flow to 200 Nl/hr. Subsequently, the reactor temperature was increased to 170⁰C, while stirred (1000 rpm) . When both the reactor temperature and pressure remained stable, part of the N₂ flow was replaced stepwise by a mixed gas flow (4.94 vol% O₂ in N₂) to start the oxidation reaction. Table 1 shows the reaction conditions used. During the reaction, the reactor temperature, off-gas flow and O₂ concentration in the off-gas were monitored. Samples (2-5 g) were taken at 0, 30, and 60 minutes for the purpose of analyzing the selectivity, the conversion and the mass balance by gas chromatography (GC) . During the run, 17.23 g of the reaction mixture was lost due to leakage at the sample point.

Table 1: Reaction conditions

Parameter Value Unit

Thermostat bath temperature 170 ± 2 ⁰C

Stirrer speed 1000 ± 30 rpm

Reactor pressure (abs) 280 ± 2 kPa

Concentration O₂ in the O₂/ N₂ gas 4.94 vol%

Concentration B₂O₃ 3.5 wt%

The conversion was aimed at 15-20% to obtain good selectivity towards secondary alcohols.

During the first 5 minutes the reaction mixture was saturated with O₂. Subsequently, the excess O₂ left the reactor via the off-gas flow, resulting in a steep increase of the off-gas O₂ concentration. When the oxidation reaction slowly commenced (period of 15 to 30 minutes) O₂ was consumed, resulting in a decrease of the off-gas O₂ concentration to 0%, where it remained throughout the run.

Simultaneously with the drop in off-gas O₂ concentration, the reactor temperature increased slightly (3°C) as a result of the exothermic oxidation reaction. The reaction was terminated after 180 minutes by reducing the O₂/ N₂ flow to zero. The reactor pressure was slowly reduced and the reactor was cooled to room temperature under a N₂ flow. The reactor mixture and reflux fraction were collected (809.5 g and 88.97 g, respectively) .

Based on the O₂ consumption during the reaction the conversion was estimated to be 20 %.

Gas chromatography provides an estimate for the weight percentages of the different components in the fractions . The reactor mixture (809.5 g) consisted mainly of unreacted paraffin (73 wt%) . Table 2 shows the other main components found.

Table 2: Components in reaction mixture after oxidation of paraffin

Component Mass Component Mass

Secondary alcohols 16 wt% Cn to Ci₃ ketones .5 wt%

Primary alcohols 0.5 wt% C₂ to C₄ lactones <o. .1 wt%

Diols -1.5 wt% C₂ to C₇ acids <0. .2 wt%

The reflux fraction consisted of an organic layer and a water layer. The organic layer (-72 g) contained predominantly decane and undecane (approximately 50 wt% and 40 wt%, respectively) . Little primary or secondary alcohols were found (<0.2 wt%) . The main contaminants were C₂ to C₇ acids (<1 wt%) . The water layer in the reflux fraction (-16 g) contained C₂ to C₇ acids and C₂ to C₄ lactones. The sample was extracted with diethyl ether to enable qualitative analysis of water layer) . Based on gas chromatography results, the overall conversion to primary and secondary monoalcohols was about 17 wt%.

Example IB: Distillations and Hydrolysis

Distillation of the reaction mixture (809.5 g) was performed in a wiped film evaporator. The feed was preheated to 50 ⁰C in order to decrease viscosity. The wall temperature was heated to about 130 ⁰C (the temperature of the heating oil was 170 ⁰C) and the temperature of the cold finger was 4-6 ⁰C. The vacuum during the distillation was 2- 6 Pa abs . The internals were rotated at 200 rpm.

Both the residue and the distillate were left overnight within the apparatus whilst under N₂. The residue (135.9 g) , distillate (595.1 g) , and cold-trap (8.92 g) fractions were collected and analyzed by gas chromatography. Some viscous dark yellow residue remained in the apparatus.

The residue (135.9 g) and 240 ml of demineralized water were stirred at 95°C whilst a N₂ flow (50 kPa abs) was applied. After 60 minutes, the mixture was transferred into a separation funnel and the water layer (bottom) was removed. The water layer was opaque and crystallized when cooled to room temperature. Again, demineralized water (160 ml) was added to the residue and stirred at 95 ⁰C for 60 minutes.

After separation, 100 ml of NaOH-solution (13.88 g NaOH pellets in 199.94 g demineralized water) was added to the residue and stirred at 95 ⁰C for 60 minutes. The mixture was transferred into a separation funnel and the NaOH layer (bottom) was removed. Again, NaOH-solution (100 ml) was added and stirred at 95 ⁰C for 20 minutes. After removing the NaOH layer the residue was washed 3 times with 160 ml of demineralized water (stirred at 95 ⁰C for 10 minutes) . A light yellow emulsion was formed during this step. The clear water layer was removed, and the emulsion (144.6 g) was "dried" overnight by bubbling N₂ through the liquid, resulting in clear deep yellow oil. The oil was stored under N₂ until its distillation was performed.

Distillation of the hydrolyzed residue was performed in a lab-scale vacuum distillation apparatus, using a 500ml round bottom flask with a 30cm single wall Vigreux fractionating column. The yield and distillation conditions of the different distillate fractions are shown in Table 3. The distillate fractions were colorless to light yellow oils. The residue was dark yellow. The distillation fractions were analyzed by gas chromatography (no internal standard used) .

Table 3: Distillation conditions and yield per distillate fraction

Distillate fraction Pressure T ^x vapour Toil bath Mass [kPa abs] [°C] [°C] [g]

AO060817-C1 0.6 53-85 115-130 1.24

AO060817-C2 0.6 86-102 131-142 16.82

AO060817-C3 0.5-0.6 103-110 142-151 23.48

AO060817-C4 0.5-0.6 110-116 151-161 16.18

AO060817-C5 49.24 (residue)

The distillate fractions C₃ and C₄ were combined (the so-called "purified alcohol mixture", designated Example Ib) and used for ethoxylation . The final yield of this purified alcohol mixture was 39.7 g. Gas chromatography showed that the purified alcohol mixture (Example Ib) having an average molecular weight of 182, contained predominantly secondary Cn, Ci₂ and C₁3 alcohols (92 wt%) . In addition, small amounts of secondary Cio alcohol (1.4 wt%) and primary Cg to C_i2 alcohols (1.8 wt%) were present. The main contaminants were Cn to Ci₃ ketones (<1.25 wt%) , paraffins (<0.25 wt%) and Ci₀ to Ci₂ diols (<0.25 wt%) . Example 1C: Ethoxylation

Ethoxylation was performed in a lab scale apparatus using a 250ml Schlenk flask equipped with magnetic stirring bar and bubble counter. The flask was filled with the alcohol mixture of Example Ib (36.0 g) , DMC catalyst (7-8 mg as solid catalyst, prepared essentially according to Example 1 of co-pending U.S. Published Application Serial No. 2005/0014979, which is herein incorporated by reference) , and toluene (7 ml) . The mixture was flushed with N₂ at 130⁰C for 20 minutes to remove the toluene and possible light contaminants (e.g. water) . A small amount of alcohol evaporated during this step and 35.66 g (196 mmol) of alcohol remained. Subsequently, ethylene oxide (EO) was introduced at such a rate that no gas passed the bubble counter. After an initial uptake due to saturation of the alcohol with EO, an induction period of 45 minutes was observed before the catalyst became active. Then the EO uptake was rapid and 62.15 g of EO was consumed within 3.5 hours. Based on this weight increase the average length of ethoxylate chains was estimated to be 7.2 equivalents of EO. Reducing the EO flow to zero stopped the reaction and the flask was flushed with N₂ for 1 hour to remove residual EO. The resulting product, designated as Example Ic (yellow oil, opaque at room temperature) , was analyzed by high performance liquid chromatography (HPLC) , ¹³C-NMR and inductively coupled plasma mass spectrometry (ICP-MS) , the description of which is given in Example ID.

¹³C-NMR was used to compare the secondary alcohol mixture before ethoxylation (Example Ib) with the ethoxylated product (Example Ic) . Before ethoxylation, signals in the 62-73 ppm region indicate the presence of primary and secondary OH-groups at all possible positions. For the ethoxylated sample these signals have fully shifted 7.5-8 ppm upward, due to the ethoxylate chain attached. No OH signals were observed so therefore the ethoxylation of the alcohol mixture was assumed to be quantitative. Furthermore, the signals at 61 and 72 ppm indicate the presence of ethoxylate end- groups. The large signal featuring at 70 ppm belongs to the carbon atoms within the ethoxylate chain. Based on the peak intensities of the ethoxylate end-groups compared to the carbons within the ethoxylate chain, the average chain length was estimated to be equivalent to 6.8 EO units for Example Ic. HPLC measurements gave an average chain length of 7.2 EO units and an amount of free alcohols of approximately 1.9 %wt . Detailed HPLC results of Example Ic on the EO distribution are given in Table 6.

The amounts of trace metals in the final product of Example Ic have been determined by ICP-MS to be in the range of 4-7 ppm for cobalt and 11-19 ppm for zinc, respectively .

Example ID: Analysis Methods

All gas chromatographic analyses on paraffins and their oxidation products were performed on a Hewlett Packard HP 5890 series II GC, equipped with PTV (Optic 2, AI Cambridge Ltd.), auto-sampler, the following column: DB-FFAP, 60m x 0.25mm x 0.25μm film thickness, using helium as carrier gas, an injection volume of lμl, split flow, FID temperature: 275 ⁰C and the following temperature program: initial temperature: 50 ⁰C for 2 minutes; temperature rate: 5 °C/minute to 150 ⁰C, followed by 10 °C/minute to 200 ⁰C and finally by 15 °C/minute to 240 ⁰C; final temperature: 240 ⁰C for 11 minutes upon analyzing LDF and derivatives and for 25.3 minutes upon analyzing HDF (Heavy Detergent Feedstock; see Example 2) and derivatives. 3-Octanol and 2-dodecanol were used as internal standards (ISTD) for GC analysis of the LDF- and HDF-based samples, respectively. For both LDF- and HDF-based samples the retention times of the linear paraffins, branched paraffins, linear secondary alcohols and most of the linear primary alcohols are known. Furthermore, several ketones, acids and lactones were identified and diols were indicated. Identification of these products was based on Gas chromatography-mass spectrometry (GC-MS) analysis of pure reference samples. Since retention times may shift due to ageing of the GC-column, they have not been specified here.

Particular classes of trace contaminants present in the paraffins, such as LDF, HDF and competitors n-paraffins, were determined by a GC x GC analysis . The response factors of the linear paraffins, branched paraffins, mono-aromatics , mono- and di-naphthenes were assumed to be identical for all species . Therefore the calculated area percentages equal the weight percentages (estimated error = 2%) .

Measurement of the average number of moles of EO per mole of secondary alcohol and residual amount of secondary alcohol was performed using high performance liquid chromatography (HPLC) . The technique for these measurements involved derivatizing the ethoxylated alcohol using 4- nitrobenzoylchloride . The product was then analyzed by gradient elution High Performance Liquid Chromatography using a Polygosil Amino stationary phase with an iso-hexane / ethylacetate / acetonitrile mobile phase. Detection was performed by ultra-violet absorbance. Quantification was by means of an internal normalization technique.

Measurement of the average number of moles of EO per mole of secondary alcohol and the residual amount of secondary alcohol of the distribution of the ethoxylated secondary alcohol was performed by ¹³C-NMR spectroscopy using a 300 or a 400 MHz apparatus.

The intake of catalyst (solids) on total intake gives rise to cobalt and zinc remaining in the product composition. The concentration of cobalt and zinc remaining in the product composition in mg/kg (= ppm wt/wt) was measured by Inductively Coupled Plasma - Mass Spectroscopy (ICP-MS) . The detection limit for cobalt and zinc is 0.5 mg/kg.

The concentration of 1,4-dioxane in the final product composition was measured by Gas Chromatography (GC) in mg/kg (= ppm wt/wt) . The technique for these GC measurements involves introducing a known amount of the alcohol ethoxylate product into a sealed vial, which is thermostated and held for 20 minutes at 50 ⁰C to allow equilibrium between the gas and liquid phases. After thermostating is complete, the product composition vapour is automatically injected into the Capillary Gas Chromatography apparatus. As the analytical column, a fused silica, 50 m x 0.32 mm internal diameter, 1.0 μm film CpSiI 5CB is used. Helium is employed as the carrier gas. Detection is performed by flame ionization. The calibration is performed using the standard addition method at 2 levels.

Example 2

Example 2A: Oxidation of Heavy Detergent Feedstock (HDF)

In the same experimental set-up and under similar conditions as described in Example IA for the oxidation of LDF, the so-called Heavy Detergent Feedstock - HDF, was oxidized. To that end the reactor was charged with ca. 1200 ml (904.6 g) HDF, Ci₄-Ci₈ paraffin (GC analysis gives typically 25 wt% tetradecane, 24 wt% pentadecane, 23 wt% hexadecane, 21 wt% heptadecane and 6 wt% octadecane, of which approximately 7 wt% are predominantly methyl-branched Ci₄-Ci₉ paraffins; GC x GC analysis gives 240 mg/kg total mono- naphthenes, 0 mg/kg total di-naphthenes and 10 mg/kg total mono-aromatics) and 31.42 g B₂O₃ (Sigma-Aldrich, 99.98%) . Table 4 shows the reaction conditions used.

Table 4 : Reaction conditions

Parameter Value Unit

Thermostat bath temperature 168 ± 4 ⁰C

Stirrer speed 1000 ± 30 rpm

Reactor pressure (abs) 271 ± 7 kPa

Concentration O₂ in the O₂/ N₂ gas 4.94 vol%

Concentration B₂O₃ 3.4 wt%

Gas chromatography provides an estimate for the weight percentages of the different components in the fractions . The reactor mixture (900 g) consisted mainly of unreacted paraffin (74 wt%) . Table 5 shows the other main components found. Table 5: Components in reaction mixture after oxidation of paraffin

Component Mass Component Mass

Secondary alcohols 20 wt% Ci₄ tO Ci₇ ketones 2 wt%

Primary alcohols >0.4 wt% lactones unknown

Diols -0.3 wt% acids unknown

Example 2B: Distillations and Hydrolysis

The reaction mixture was distilled three times in the wiped film evaporator to remove the unreacted paraffin. After the three distillations less than 1.5 wt% of HDF paraffins remained in the residue. Hydrolysis and fractional distillation were carried out similarly to Example IB. Two purified secondary alcohol fractions were isolated, designated Example 2b and Example 2b' .

The light fraction, Example 2b, (52.5 g, having an average molecular weight of 225) consisted mainly of Ci₄-Ci₆ alcohols (89 wt%) . In addition small amounts of secondary Ci₇ alcohols (3 wt%) and primary alcohols (1 wt%) were present. The main contaminants were paraffins (-1.5 wt%) , Ci₃ to Ci₇ ketones (-1 wt%) and Ci₃ to Ci₅ diols (<0.5 wt%) .

The heavy fraction, Example 2b', (45.1 g, having an average molecular weight of 241) consisted mainly of Ci₅-Ci₇ alcohols (89 wt%) . In addition small amounts of secondary Ci₄ and Ci8 alcohols (-1.5 wt% each) were present. The main contaminants were paraffins (<1 wt%) , Ci₃ to Ci₇ ketones (<1 wt%) and Ci₃ to Ci₆ diols (<4 wt%) .

Example 2C: Ethoxylation

Both Examples 2b and 2b' have been ethoxylated to a 2-EO level in a lab-scale apparatus using a 250-ml Schlenk flask equipped with a magnetic stirring bar and a bubble counter. The flask was filled with 50.05 g of Example 2b, 8 mg of DMC as solid catalyst (prepared essentially according to Example 1 of co-pending U.S. Published Application Serial No. 2005/0014979, which is herein incorporated by reference) , and toluene (7 ml) . The mixture was flushed with nitrogen at 130 ⁰C for 20 minutes to remove toluene and possible light contaminants, such as water.

Subsequently ethylene oxide (EO) was introduced at such a rate that no gas passed the bubble counter. After an initial uptake due to saturation of the alcohol with EO, an induction period of 40 minutes was observed before the DMC catalyst became active. Then the EO uptake was rapid and 20.88 g of EO was consumed within 2.5 hours. Based on this weight increase the average length of ethoxylate chains was estimated to be 2.1 equivalents of EO. Reducing the EO flow to zero stopped the reaction and the flask was flushed with nitrogen for 1 hour to remove the residual EO. The resulting product (70.9 g) , designated sample 2c, was analyzed by ¹³C- NMR to have an average EO-chain length of about 2.

An analogous procedure was used to ethoxylate Example 2b' (41.97 g) to a 2.1 EO level. Here the induction time was 30 minutes and the required amount of 16.28 g EO was consumed in 1.5 hours, resulting in 58.3 g of product, designated sample 2c' . Based on this weight increase the average length of ethoxylate chains of sample 2c' was estimated to be 2.1 equivalents of EO.

Surprisingly the difference in diol contents between the HDF-derived secondary alcohols of Examples 2b (<0.5 wt%) and Example 2b' (<4 wt%) and the LDF-derived secondary alcohol of Example Ib (<0.25 wt%) does not appear to have a large effect on the induction period, rate and efficiency of DMC catalyzed ethoxylation .

Example 2D (Sulfation)

Sample 2c was subjected to sulfation. Sulfation was carried out with gaseous sulfur trioxide in a glass falling film reactor approximately one meter in length and 5 mm in diameter. Sulfur trioxide was generated by passing sulfur dioxide in dry air over a heated catalyst bed containing vanadium pentoxide. The hot stream of SO3 in air was cooled by a heat exchanger, and then admitted to the thin film reactor at approximately 1 gram of S0₃/minute. The secondary alcohol ethoxylate (sample 2c) was pumped to the falling film reactor at 3.8 grams/minute to give a S03/ethoxylate molar ratio of 0.80. A nitrogen flow of 16 normal liters per minute was used to generate a thin liquid film. The temperatures of the three zones of the reactor column were controlled at 25°C using circulator baths. The product sulfate was collected at the bottom of the falling film column in a solution of sodium hydroxide mixed in a blender. A ratio of 1.2 moles NaOH/mole of sulfate was employed. The product was analyzed and found to contain 27 wt% active matter. UOM (unreacted organic matter) was 4.7 wt% and sulfate content was 0.17 wt% .

Example 3 (comparative)

For the oxidation of the HDF (for its composition see Example 2A) , under the conditions essentially the same as in Example IA, except for the scale (one third) and the pressure (atmospheric pressure) , an induction period of 30 minutes was observed. For Petresa's n-paraffin of similar average carbon number (Petrepar 147), obtained from kerosene extraction, an induction period of about 50 minutes was recorded under identical conditions (see Figure 1) . According to GC x GC analysis Petrepar 147 gives 26 wt% n-tetradecane; 61 wt% n- pentadecane; 10 wt% n-hexadecane; 1 wt% n-heptadecane; <0.5 wt% >n-heptadecane; 0.5 wt% branched Ci₄-Ci₇ paraffins; 1 wt% total mono- and di-naphthenes and about 500 mg/kg of total mono-aromatics . During these comparative oxidation experiments samples were taken every 30 minutes, until the oxidations had progressed for 180 minutes. The total secondary alcohol content, as determined by GC after hydrolysis of each sample (see methods described in Example ID) , is given in Figure 1 as a function of time to establish the induction period and the rate of secondary alcohol formation (paraffin oxidation) .

Hence, with Shell's HDF, which is almost free of aromatics (10 mg/kg) and naphthenes (240 mg/kg) , but contains besides n-paraffins in the Ci₄-Ci₉ range some 7 %wt predominantly methyl-branched paraffins a shorter induction period, but a similar oxidation rate observed, as for Petrepar 147, the almost 100% linear Ci₄-Ci₇ paraffins from Petresa, containing approximately 500 mg/kg of mono-aromatics and 1 wt% naphthene contaminants .

Example 4 (comparative) DMC catalyzed ethoxylation of the secondary alcohol 2-undecanol

2-Undecanol (10.0 g) and 0.2 g of a 3 wt% slurry of a double metal cyanide catalyst in polypropylene glycol 400 prepared according to Example 1 of co-pending U.S. Published Application Serial No. 2005/0014979, which is herein incorporated by reference), were stirred in a Schlenk vessel, equipped with a magnetic stirring bar. The vessel was immersed in an oil bath kept at 120⁰C. Ethylene oxide (EO) was dosed at atmospheric pressure. After an induction period of ca. 3h, EO consumption started. The vessel was weighed several times and after the consumption of 17.9 g of EO the reaction was stopped and stripped for about 5 minutes with nitrogen. The average number of moles of EO per molecule was 7.0, the level of free alcohol was 0.7 wt% (both according to HPLC) and the level of 1,4-dioxane was <5 mg/kg (by GC), using the methods as described in Example ID. The ethoxylate distribution as obtained by HPLC is shown in Table 6 below.

Example 5 (comparative)

Example 4 was repeated except that before the EO was added, 1 ml toluene was added and the mixture stripped with nitrogen at 130^° C (to remove water) . Then to the remaining reaction mixture (9.3 g) EO was added, which reacted immediately. EO dosing was stopped after the consumption of 16.1 g.

The average number of moles of EO per molecule was 6.5, the level of free alcohol was 1.1 wt% and the level of 1,4- dioxane was <10 mg/kg, using the same methods as used in Example 4. The E0-distribution (by HPLC) is shown in Table 6 below.

Example 6 (comparative) The preparation of an ethoxylate derived from the secondary alcohol, 2-undecanol, and having an average of about 7 EO groups per molecule, produced by acid catalysis using hydrogen fluoride / boric acid

A magnetically stirred PTFE bottle was charged with 15.2 g of 2-undecanol (>98% pure, purchased from FLUKA A. G., Switzerland) , 2.0 g of a 5 % solution of HF (wt/wt) in 2- undecanol and 20 mg of orthoboric acid (purchased from Aldrich) . Hence, the total amount of 2-undecanol was 17.2 g (0.1 mol) . Then 31.0 g (0.705 mol) of ethylene oxide was bubbled through the solution at such a rate that the bubbles were consumed before reaching the surface (at atmospheric pressure) . The temperature rapidly increased and was maintained at about 70 ⁰C by external cooling. The reaction was stopped after the desired amount of ethylene oxide had been consumed and 48.3 g of product was obtained. A sample of the product of Example 6 was analyzed for the average number of moles of EO per molecule and the level of free alcohol by HPLC and level of 1,4-dioxane by GC, using the methods described in Example ID. The results are as follows: average EO number = 6.6 EO-units/mol; free alcohol = 0.7 wt%; 1,4-dioxane content = 41000 mg/kg. Detailed results on the EO distribution of Examples Ic, 4, 5 and 6, as obtained by HPLC, are given in Table 6.

The ethoxylate distribution of the DMC catalyzed ethoxylation of secondary alcohols mixture of Example Ib, leading to the product of Example Ic is about as narrow as those of the DMC catalyzed ethoxylation of the secondary alcohol, 2-undecanol, of comparative Examples 4 and 5, and of the HF/boric acid catalyzed ethoxylation of the secondary alcohol, 2-undecanol, of comparative Example 6. Moreover, in the DMC catalyzed ethoxylation the 1,4-dioxane formation is almost absent, whereas upon acid catalyzed ethoxylation ethoxylate chain degradation occurs with concomitant formation of large amounts of 1,4-dioxane.

TABLE 6

Claims

C L A I_ M S_

1. A process for making secondary alcohol alkoxy sulfates which comprises:

(a) reacting carbon monoxide and hydrogen under Fischer-Tropsch conditions in the presence of a Fischer-Tropsch catalyst to produce a reaction mixture comprising paraffins,

(b) contacting the paraffins with oxygen in the presence of an oxidation catalyst to produce secondary alcohols,

(c) contacting the secondary alcohols with an alkylene oxide in the presence of a double metal cyanide catalyst to produce secondary alcohol alkoxylates, and

(d) sulfating the secondary alcohol alkoxylates.

2. The process of claim 1 wherein the oxidation catalyst in step (b) is selected from the group consisting of orthoboric acid, metaboric acid, boric oxide and boric esters.

3. The process of claim 2 wherein step (b) comprises the following steps :

(i) mixing at least a portion of the paraffins and orthoboric acid,

(ii) dehydrating the mixture to form metaboric acid, (iii) introducing the paraffin and metaboric acid mixture and the portion of the paraffins not mixed with the orthoboric acid in step (i) to an oxidation reactor,

(iv) adding an oxidizing gas to the oxidation reactor to form secondary alcohol borate esters,

(v) separating the unreacted paraffins and other low molecular weight compounds from the oxidation reaction mixture, (vi) hydrolyzing, methanolyzing or alcoholyzing the borate esters to form secondary alcohols and boric acid, trimethyl borate or trialkyl borate,

(vii) separating the secondary alcohols from the boric acid or boric acid derivatives, and

(viii) recovering the secondary alcohols.

4. The process of claims 1 to 3 wherein the paraffins have a carbon number of 15 or more, borate esters of secondary alcohols are formed and the borate esters are separated from the unreacted paraffins by application of high vacuum flashing or stripping, using a wiped film evaporator, solvent-solvent extraction or by application of membrane separation techniques.

5. The process of claims 1 to 4 wherein step (d) comprises reacting the secondary alcohol alkoxylates with a sulfur trioxide-inert gas mixture comprising from 1 to 8 volume percent sulfur trioxide in a thin film reactor and neutralizing the reaction product to produce secondary alcohol alkoxy sulfates.

6. The process of claims 1 to 5 wherein step (a) comprises reacting carbon monoxide and hydrogen in the presence of a Fischer-Tropsch catalyst comprising one or more metals from groups 8, 9, and 10 of the Periodic Table of Elements at a temperature of from 125 to 350⁰C and a pressure from 500 to 15,000 kPa abs and then separating from the reaction product at least one hydrocarbon fraction comprising paraffins having from 15 to 30 carbon atoms.

7. A process for making secondary alcohol alkoxylates which comprises :

(a) reacting carbon monoxide and hydrogen under

Fischer-Tropsch conditions in the presence of a Fischer-Tropsch catalyst to produce a reaction mixture comprising paraffins, (b) contacting the paraffins with oxygen in the presence of an oxidation catalyst to produce secondary alcohols, and

(c) contacting the secondary alcohols with an alkylene oxide in the presence of a double metal cyanide catalyst to produce secondary alcohol alkoxylates.

8. The process of claim 7 wherein the oxidation catalyst in step (b) is selected from the group consisting of orthoboric acid, metaboric acid, boric oxide and boric esters.

9. The process of claim 8 wherein step (b) comprises the following steps :

(i) mixing at least a portion of the paraffins and orthoboric acid,

(ii) dehydrating the mixture to form dehydrated boric acid, boric oxide or metaboric acid,

(iii) introducing the paraffin and dehydrated boric acid, boric oxide or metaboric acid mixture and the portion of the paraffins not mixed with the orthoboric acid in step (i) to an oxidation reactor,

(iv) adding an oxidizing gas to the oxidation reactor to form secondary alcohol borate esters,

(v) separating the unreacted paraffins and other low molecular weight compounds from the oxidation reaction mixture,

(vi) hydrolyzing, methanolyzing or alcoholyzing the borate esters to form secondary alcohols and boric acid, trimethyl borate or trialkyl borate,

(vii) separating the secondary alcohols from the boric acid or boric acid derivatives, and

(viii) recovering the secondary alcohols.

10. The process of claims 7 to 9 wherein the paraffins have a carbon number of 15 or more, borate esters of secondary alcohols are formed and the borate esters are separated from the unreacted paraffins by application of high vacuum flashing or stripping, using a wiped film evaporator, solvent-solvent extraction or by application of membrane separation techniques.

11. The process of claims 7 to 10 wherein step (a) comprises reacting carbon monoxide and hydrogen in the presence of a Fischer-Tropsch catalyst comprising one or more metals from groups 8, 9, and 10 of the Periodic Table of Elements at a temperature of from 125 to 350 ⁰C and a pressure from 500 to 15,000 kPa abs and then separating from the reaction product at least one hydrocarbon fraction comprising paraffins having from 15 to 30 carbon atoms.