WO1992008687A1

WO1992008687A1 - Process for preparing n-alkyl polyhydroxy amines in amine and amine/water solvents and fatty acid amides therefrom

Info

Publication number: WO1992008687A1
Application number: PCT/US1991/006979
Authority: WO
Inventors: Robert Edward Shumate; Don Clifford Burdsall; Jeffrey John Scheibel; Daniel Stedman Connor
Original assignee: The Procter & Gamble Company
Priority date: 1990-11-09
Filing date: 1991-09-25
Publication date: 1992-05-29
Also published as: FI932079A; BR9106918A; JPH06501473A; FI932079A0; AU8711691A; MX9101372A; CN1061959A; EP0556348A1; CA2092563A1

Abstract

Amines such as methyl amine are reacted with materials such as reducing sugars in amine or amine/water solvents to prepare N-alkyl polyhydroxy amines. Accordingly, glucose is reacted with methyl amine and the resulting adduct is hydrogenated to yield N-methylglucamine. The N-alkyl polyhydroxy amines can be subsequently reacted with fatty esters to provide polyhydroxy fatty acid amides useful as detersive surfactants. Thus, detersive surfactants are available from non-petrochemical precursors such as sugars and sugar sources such as corn syrup, and fatty acid esters derivable from various fats and oils.

Description

PROCESS FOR PREPARING N-ALKYL POLYHYDROXY AMINES IN AMINE AND AMINE/WATER SOLVENTS AND FATTY ACID AMIDES THEREFROM

FIELD OF THE INVENTION The present invention relates to a chemical process for preparing N-alkyl polyhydroxy amines, especially N-methylgluc¬ amine, as well as fatty acid derivatives thereof useful as surfactants.

BACKGROUND OF THE INVENTION

The manufacture of N-alkyl polyhydroxy amines, such as N- methylglucamine, has been known for many years, and such materials are available commercially. In the main, however, their use has been somewhat limited and such materials have been relatively expensive. Recently, there has been occasion to employ N-alkyl polyhydroxy amines in reactions^' with fatty acid esters to prepare fatty acid polyhydroxy amide detersive surfactants for use in conventional home laundering products. As can be imagined, were the cost of N-alkyl polyhydroxy amines to remain high, this laundry detergent use of the fatty acid polyhydroxy amide surfact¬ ants would be impossible. Accordingly, there is a continuing search for quick, inexpensive means for preparing N-alkyl polyhy¬ droxy amines on a commercial scale.

Moreover, it has been determined that care must be taken in preparing N-alkyl polyhydroxy amines in a form that is suitable for subsequent reaction with fatty acid methyl esters, since contamination of the N-alkyl polyhydroxy amines with, for example, hydrogenation catalysts such as Raney nickel, unreacted sugars, water, N-methylglucosyl amine intermediates, and the like, can seriously impact on the formation of the fatty acid polyhydroxy amide formation. For example, browning reactions, with the formation of undesirable color bodies, can occur, especially in the presence of N-methylglucosyl amine. The formation of various undesirable by-products such as cyclic materials and/or ester- amides can also occur. In a worst case scenario, by-product formation can be so high that the desired reaction of the N-alkyl polyhydroxy amine with the fatty acid methyl ester is essentially stopped in its entirety, with the formation of black, intractable tarry products. The present invention provides a simple means for preparing N-alkyl polyhydroxy amines especially N-methyl glucamine, in high yields, with low color formation, and in a form that is particu¬ larly suited for subsequent reaction with fatty acid esters.

BACKGROUND ART A number of years ago, processes were explored for making textile assistants or detergents from fatty acids or their deriva¬ tives in combination with N-alkylglucamines, the latter made by reductive a ination of glucose. Glucose reductive amination processes are more fully disclosed in U.S. Patent 2,016,962, Flint et al, issued October 8, 1935.

U.S. Patent 1,985,424, Piggott, issued December 25, 1934 discloses manufacturing "textile assistants" by reacting (a) the product of heating^'glucose and aqueous methylamine in presence of hydrogen and a hydrogenating catalyst under pressure with (b) an organic carboxylic acid such as stearic acid or oleic acid. The condensation product, prepared at about 160^*C, is said to be "predominantly, if not exclusively, an amide" and is assertedly of the formula R-C0-NR₁-CH₂-(CH0H)₄-CH₂0H wherein R is an alkyl radical containing at least 3 carbon atoms, while R-. is hydrogen or an alkyl radical.

U.S. Patent 2,703,798, Schwartz, issued March 8, 1955 asserts that compositions produced by reacting fatty acids or acid anhy¬ drides with N-alkylglucamines (presumably such as the process as taught by Piggott) have poor color and poor detergency properties. It is indeed chemically reasonable that more than one compound can be formed by the Piggott process. Piggott makes no attempt to quantitatively prove the structures of the compounds or mixtures he prepared.

Schwartz ('798) goes on to report an improvement as a result of reacting fatty ester (as distinct from fatty acid or anhydride) with N-alkylglucamines. Although this process may overcome one or another deficiency of the art, such as of Piggott, it now tran¬ spires that the Schwartz process still has difficulties, in particular, in that complex mixtures of compounds can be formed even by the Schwartz process. The reaction may take several hours and the process can fail to give high quality product. Neither the process of Piggott not the process of Schwartz is known to have ever borne fruit in commercial practice.

In more detail, Schwartz notes that only one of several possible chemical reactions takes place when N-monoalkylglucamines are condensed with fatty esters or oils. The reaction is said to give compounds formulated as amides, e.g., 0 Rⁱ

R²-C- -CH₂(CH0H)₄-CH₂0H (I) where R² is fatty alkyl and R¹ is a short-chain alkyl, typically methyl. This structure is apparently the same as the structure proposed by Piggott. Schwartz contrasts the single-product outcome he believes he secures with compounds he asserts are actually produced when acids are reacted with N-alkylglucamines, namely mixtures of the amide (I) with one or more by-products, to which he assigns estera ide and estera ine structures and which assertedly include compounds which are "inert and waxy, impairing the surface activity of" the structure (I) amide.

According to Schwartz, approximately equi olar proportions of N-monoalkylglucamines can be reacted with fatty alkyl esters by heating at UO'C-ΣSO'C, preferably 160^*C-180^*C at normal, reduced or superatmospheric pressures for a period "somewhat in excess of one hour" during which time two initially immiscible phases merge to form a product said to be a useful detergent.

Suitable N-monoalkylglucamines are illustrated by N-methyl¬ glucamine, N-ethylglucamine, N-isopropylglucamine and N-butylgluc- amine. Suitable fatty alkyl esters are illustrated by the product of reacting a C₆-C₃₀ fatty acid with an aliphatic alcohol e.g., methyl ester of 1auric acid. Mixed glycerides of Manila oil or mixed glycerides of cochin coconut oil can apparently also be used as the fatty ester. When the glucamine is N-methylglucamine, the corresponding products with these fatty esters are characterized as the "fatty acid amides of N-methylglucamine", which are useful detergent surfactants. Another specific composition reported is assertedly "N-isopropylglucamine coconut fatty acid amide". U.S. Patent 2,993,887, Zech, issued July 25, 1961 reveals there is even more complexity to the reactions of fatty substances with N-methylglucamine. In particular, Zech asserts that the products of high-temperature reaction (180^βC-200^βC) within the range disclosed by Schwartz have cyclic structures. No fewer than four possible structures are given. See '887 at column 1, line 63 - column 2, line 31.

What is now believed actually to be provided by the fatty ester- N-alkylglucamine process of Schwartz are compositions comprising mixtures of formula (I) compounds together with appreciable proportions (e.g., about 25%, often much more) of several other components, especially cyclic glucamide by-products (including but not limited to the structures proposed by Zech) or related derivatives such as estera ides wherein as compared with formula (I) at least one -OH moiety is esterified.

Moreover, a reinvestigation of Schwartz suggests that there are other significant unsolved problems in the process, including a tendency to form trace materials imparting very unsatisfactory color and/or odor to the product. More recently, the work of Schwartz notwithstanding, Hildreth has asserted that compounds of formula (I) are new. See Biochem. J., 1982, Vol. 207, pages 363-366. In any event, these composi¬ tions are given a new name: "N-D-gluco-N-methylalkanamide deter¬ gents", and the acronym "MEGA". Hildreth provides a solvent- assisted process for making the compounds differing seminally from Schwartz in that it returns to the use of a fatty acid reactant, instead of fatty ester. Moreover, Hildreth relies on pyrid- ine/ethyl chlorofor ate as the solvent/activator. This process is specifically illustrated for octanoyl-N-methylglucamide ("OMEGA"), nonanoyl-N-methylglucamide ("MEGA-9") and decanoyl-N-methylgluc¬ amide ("MEGA-10"). The process is said to be cheap and high- yield. One must of course assume that "cheap" is relative and is meant in the sense of specialized biochemical applications of interest to the author: in terms of large-scale detergent anufac- ture, the use of pyridine and ethyl chloroformate would hardly be viewed as consistent with an economic or environmentally attrac¬ tive process. Therefore, the Hildreth process is not further considered herein. Hildreth and other workers have purified certain formula (I) compounds, e.g., by recrystallization, and have described the properties of some of the structure (I) compounds. Recrystal¬ lization is, of course, a costly and potentially hazardous (flammable solvents) step in itself, and large-scale detergent manufacture would be more economical and safer without it.

According to Schwartz supra, the products of the Schwartz process can be used for cleaning hard surfaces. According to Thomas Hedley & Co. Ltd. (now Procter & Gamble), British Patent 809,060 published February 18, 1959, formula (I) compounds are useful as a surfactant for laundry detergents such as those having granular form. Hildreth (supra) mentions use of compounds of formula (I) in the biochemistry field as a detergent agent for solubilizing plasma membranes and EP-A 285,768, published December 10, 1988 describes application of formula (.1) compounds as a thickener. Thus, these compounds, or compositions containing them, can be highly desirable surfactants-.

Yet another process for. making compositions comprising formula (I) compounds is included in the above-identified disclosure of improved thickeners. See EP-A 285,768. See also H. Kelkenberg, Tenside Surfactants Detergents 25 (1988) 8-13, inter al ia for additional disclosures of processes for making N-alkylglucamines which, along with the above-identified art- disclosed N-alkylglucamine processes can be combined with the instant process for an overall conversion of glucose and fatty materials to useful surfactant compositions.

The relevant disclosures of EP-A 285,768 include a brief statement to the effect that "it is known that the preparation of chemical compounds of formula (I) is done by reacting fatty acids or fatty acid esters in a melt with polyhydroxy alkylamines which can be N-substituted, optionally in the presence of alkaline catalysts". The above-referenced art strongly suggests that this statement is a gross simplification or is inaccurate. EP-A 285,768 does not cite any references in support of the quoted statement, nor has any reference other than EP-A 285,768 been found which actually does disclose any catalytic condensation of N-alkylglucamines with fatty esters or fatty triglycerides. The European Patent Application contains the following

Example entitled "Preparation of N-methyl-coconut fatty acid glucamide" in which "Na methylate" is understood to be synonymous with "sodium methoxide" and which has been translated from the German:

In a stirred flask 669 g (3.0 mol) of coconut fatty acid methyl ester and 585 g (3.0 mol) of N-methyl gluca ine with the addition of 3.3 g Na methylate were gradually heated to 135*C. The methanol formed during the reaction was condensed under increasing vacuum at 100 to 15 mbar in a cooled collector. After the meth¬ anol evolution ended the reaction mixture was dissolved in 1.51 of warm isopropanol, filtered and crystallized. After filtration and drying 882 g (=76% of theoretical) of waxy N-methyl coconut fatty acid glucamide was obtained. Softening point = 80 to 84^*C; Base number: 4 mg. KOH /g.

EP-A 285,768 continues with the following: "In a similar manner the following fatty acid glucamides were prepared:

N-methyl 1auric acid glucamide N-methyl myristic acid glucamide N-methyl palmitic acid glucamide N-methyl stearic acid glucamide

To summarize some important points of what can be gleaned from the art, the aforementioned Schwartz patent teaches that the problem of making formula (I) compounds from fatty esters or triglycerides and an N-alkylglucamine is solved by selecting fatty ester (instead of fatty acid) as the fatty reactant, and by doing simple uncatalyzed condensations. Later literature, such as Hildreth, changes direction back to a fatty acid-type synthesis, but does not document either that the teaching of the Schwartz patent is in error or how, short of making highly pure formula (I) compounds, to make such surfactants to detergent for ulator's specifications. On the other hand, there has been one disclosure, in a totally different technical field, of sodium methoxide- catalyzed formula (I) compound synthesis. As noted, the procedure involves gradual temperature staging up to 135^βC and recrystallizing the product. SUMMARY OF THE INVENTION

The present invention encompasses a process (carried out under non-oxidizing conditions) for preparing N-alkyl polyhydroxy amines, comprising the steps of: a) reacting a reducing sugar or reducing sugar derivative with a primary amine reactant in an amine solvent at mole ratios of amine:sugar not greater than about 30:1 to provide an adduct; b) reacting said adduct from step (a) dissolved in said solvent with hydrogen under mild conditions in the presence of a metal catalyst; and c) removing said catalyst and substantially removing the water and unreacted amines from the reaction mixture to secure the N-alkyl polyhydroxy amine.

A preferred process herein is wherein the sugar material is a reducing sugar, especially glucose, and the amine compound is a member selected from the group consisting of Cχ-C₄ alkyl or hydroxyalkyl amines. When the amine (both reactant and solvent) is monomethyl amine (hereinafter, simply "methyl amine") and the sugar is glucose, the preferred reaction product N-methylglucamine is secured. A particular advantage of the present process is that it can be carried out in the presence of water in step (a). Accordingly, raw materials such as corn syrup, hydrated glucose, and the like, can be used as the sugar source.

The catalyst used in step (b) is preferably a nickel catalyst, especially nickel on a substrate such as silica or silica/alumina. Raney nickel can also be used, but is less preferred.

Step (a) of the process is preferably carried out at a temperature of from about O'C to about 80'C, preferably from about 30^*C to about 60'C. Step (b) of the process is preferably carried out at a temperature of from about 40^*C to about 120°C, preferably from about 50^βC to about 90^*C. Steps (a) and (b) of the R-l process are preferably conducted under non-oxidizing conditions (e.g., inert gas) to provide good color. Catalyst removal is, of course, done under inert conditions due to fire hazard.

The invention herein also encompasses an overall process for preparing polyhydroxy fatty acid amide surfactants which includes an amide-forming reaction comprising reacting the N-alkyl polyhy¬ droxy amine materials prepared in the foregoing manner with. fatty acid esters in an organic hydroxy solvent in the presence of a base catalyst. The formation of such surfactants with high conversions, high purity and low color is an especially beneficial result of the present process,_* since it allows the detergent formulator to pump or otherwise incorporate the polyhydroxy fatty acid amide reaction product plus the reaction solvent such as 1,2-propylene glycol, glycerol, or alcohol (e.g., in liquid detergents) directly into the final detergent formulation. This offers economic advantages in that a final solvent removal step is rendered unnecessary, particularly where glycols or ethanol is used.

Moreover, the process herein allows the formulator to prepare high quality polyhydroxy fatty acid amide surfactants without purification of the N-alkylglucamine.

All percentages, ratios and proportions herein are by weight, unless otherwise specified.

DETAILED DESCRIPTION OF THE INVENTION The reaction for the preparation of the polyhydroxyamines herein can be termed the "R-l" reaction, and is illustrated by the formation of N-methylglucamine, wherein R¹ is methyl.

CH₃NH₂(xs) R^!NH₂ + glucose ^•* Adduct + H₂0 catalyst Adduct + H₂ -> R-*N(H)CH₂(CH0H)₄CH₂0H

The reactants, solvents and catalysts used in the R-l reaction are all well-known materials which are routinely avail¬ able from a variety of commercial sources. The following are nonlimiting examples of materials which can be used herein. Amine Material - The amines useful in the R-l reaction herein are primary amines of the formula

wherein R¹ is, for example, alkyl, especially Ci-C₄ alkyl, or C_x-C hydroxyalkyl . Examples include methyl, ethyl, propyl, hydroxyethyl, and the like. Nonlimiting examples of amines useful herein include methyl amine, ethyl amine, propyl amine, butyl amine, 2-hydroxypropyl amine, 2-hydroxyethyl amine; methyl amine is preferred. All such amines are sometimes jointly referred to as "N-alkyl amines". Polyhydroxy Material - A preferred source of polyhydroxy materials useful in the R-l reaction comprises reducing sugars or reducing sugar derivatives. More specifically, reducing sugars useful herein include glucose (preferred), maltose, fructose, maltotriose, xylose, galactose, lactose, and mixtures thereof. Catalyst - A variety of hydrogenation catalysts can be used in the R-l reaction. Included among such catalysts are nickel (preferred), platinum, palladium, iron, cobalt, tungsten, various hydrogenation alloys, and the like. A highly preferred catalyst herein comprises "United Catalyst G49B" a particulate Ni catalyst supported on silica, available from United Catalysts, Inc., Louisville, Kentucky.

Solvent - Formation of the adduct in the R-l process is carried out using an excess of the amine as the solvent. The excess amine also is used in the subsequent reaction with hydrogen. Optionally, the amine can be replaced with an alcohol, such as methanol, for the hydrogen reaction. Typical examples of solvents useful herein in the formation of the amine-sugar adduct include methyl amine, ethyl amine, and hydroxyethyl amine; methyl amine is preferred; methyl amine/water solvent can also be used. General R-l Reaction Conditions - Reaction conditions for the R-l reaction are as follows.

(a) Adduct formation - The reaction time used for adduct formation will typically be on the order of 0.5-20 hours, depending somewhat on the reaction temperature chosen. In general, lower reaction temperatures in the range of.O'C-80'C require longer reaction times, and vice-versa. In general, over the preferred SO'C-δO'C reaction temperature range, good adduct yields are achieved in 1-10 hours. Generally good adduct formation is achieved at about a 4:1 to 30:1 mole ratio of amine:sugar. Typical sugar reactant concentrations in the amine solvent are in the 10%-60% (wt.) range. Adduct formation can be carried out at atmospheric or superatmospheric (preferred) pressures.

(b) Reaction with Hydrogen - The reaction with hydrogen can typically be run, for example, at temperatures of 40'C-120'C at 50-1,000 psi or, for example, at 50'C-90^*C at 100-500 psi for periods of 0.1-35 hours, generally 0.5-8 hours, typically 1-3 hours. The adduct/solvent solution used in the hydrogen reaction is typically at a 10%-60% (wt.) solute level. (It will be appreciated that the selection of hydrogen reaction conditions will depend somewhat on the type of pressure equipment available to the formulator, so the above-noted reaction conditions can be varied without departing from this invention.) Hydrogen reaction catalyst levels are typically 1% to 40%, preferably about 2% to about 30% solids weight, calculated based on wt. catalyst:wt. reducing sugar substituent for batch processes. Of course, continuous processes could be run at much higher catalyst levels. The product of step (b) can be dried by solvent/water stripping, or by crystallization, trituration, or by means of effective drying agents.

EXAMPLE I

Anhydrous glucose (36.00 g; Aldrich Chemical Company) is weighed into a glass liner. The glass liner is placed into a dry-ice bath and methyl amine gas (68.00 g; Matheson) is condensed into the glass liner. The liner is then loaded into a rocking autoclave (500 ml capacity). The autoclave is heated to 50'C and rocked for 5 hours at 50^*C under 600 psig nitrogen to form the adduct (N-methylglucosylamine). The reaction is then cooled in a dry-ice bath. The autoclave is then vented cold. Raney nickel

(7.2 g of a 50% suspension in water, W/2 type, Aldrich Chemical

Company) is added. The reaction is heated to 50'C under 500-600 psig hydrogen and is rocked for 16 hours. The reaction is cooled in dry-ice bath and vented and purged with nitrogen. The reaction solution is pressure filtered through a Zeofluor filter (PTFE, 47 mm, 0.5 micron filter) with a 4 inch bed of Celite 545 (Fisher

Scientific Company). The filtrate is concentrated under a stream of nitrogen to give 8.9 g of white solid. The Celite plug is washed with about 300 mis of water and the water is stripped on a rotary evaporator to give 18.77 g of white solid. The two solids are combined as they are analyzed to be of similar composition (90+ purity by GC analysis). The product is N-methyl glucamine. EXAMPLE II

The process of Example I is repeated in a stirred autoclave fitted with a fritted exit filter, a triple impeller stirrer, outlet and inlet tubes and a baffle. Reagents and reaction conditions for the preparation of N-methyl glucamine are as follows: 15 g of 20% G49B catalyst (Ni/silica; United Catalyst) and 75 g glucose powder (Aldrich, Lot 07605LW) are slurried in 160 mis methanol and pretreated with H₂ for one hour (50^*C). The mixture is then cooled and the methanol is removed by pressure.

The reactor is cooled to less than 5'C and charged with 76 mis of liquid methyl amine.

The reaction mixture is slowly heated to 60'C over 46 minutes at 250 psi hydrogen and sampled. Heating is continued at 60'C for 20 minutes and sample 2 is taken. Heating is continued at 60^*C for 46 minutes (sample 3) and ^'then at 60'C for 17 minutes (sample 4). The reaction mix is heated to 70^*C for an additional 33 minutes (sample 5). Total reaction time is 2.7 hours. The dried product is 93.2% N-methyl glucamine (GC analysis).

The polyhydroxyamine products of the aforesaid R-l reaction, preferably with water substantially removed, are desirable and can be further employed in an amide-forming reaction which is desig¬ nated herein as the "R-2" reaction. A typical R-2 amide-forming reaction herein can be illustrated by the formation of lauroyl N-methyl glucamide, as follows. methanol R²C00Me + MeN(H)CH₂(CH0H)₄CH₂0H -»^• methoxide

R²C(0)N(Me)CH₂(CH0H)₄CH₂0H + MeOH wherein R² is C^^ alkyl.

Thus, the invention herein encompasses an overall process for preparing polyhydroxy fatty acid amide surfactants, all as noted above for the R-l process, comprising:

(a) reacting a reducing sugar (preferably glucose) or reducing sugar derivative with an amine reactant (preferably methyl amine) in an amine solvent (preferably, methyl amine) to provide an adduct;

(b) reacting said adduct from step (a) dissolved in said amine solvent with hydrogen in the presence of a metal catalyst;

(c) removing said catalyst and substantially removing water and excess amine solvent from the reaction mixture to provide the polyhydroxyamine reaction product; and, thereafter, per the R-2 process, (d) reacting said substantially anhydrous polyhydroxyamine product from step (c) with a fatty acid ester in an organic hydroxy solvent (preferably, methanol or propylene glycol) in the presence of a base catalyst to form the polyhydroxy fatty acid amide surfactant (preferably, at a temperature below about 100'C)-; and

(e) optionally, when the reaction step (d) is essentially complete, removing said solvent used in step (d). More specifically, the combination of R-l and R-2 reactions herein provides an overall process (R-l plus R-2) which can be used to prepare polyhydroxy fatty acid amide surfactants of the formula:

0 R¹

II I

(I) R² - C - N - Z wherein: R^l is H, Cj-C₄ hydrocarbyl, 2-hydroxyethyl , 2-hydroxy propyl, or a mixture thereof, preferably Ci-C₄ alkyl, more preferably C_x or C₂ alkyl, most preferably C_x alkyl (i.e., methyl); and R² is a C₅-C₃₁ hydrocarbyl moiety, preferably straight chain C₇-C₁₉ alkyl or alkenyl, more preferably straight chain C₉-C₁₇ alkyl or alkenyl, most preferably straight chain C₁₁-C₁₇ alkyl or alkenyl, or mixture thereof; and Z is a pol hydroxyhydrocarbyl moiety having a linear hydrocarbyl chain with at least 3 hydroxyls directly connected to the chain, or an alkoxylated derivative (preferably ethoxylated or propoxylated) thereof. Z preferably will be derived from a reducing sugar in a reductive amination reaction; more preferably Z is a glycityl moiety. Suitable reducing sugars include glucose, fructose, maltose, lactose, galactose, mannose, and xylose. As raw materials, high dextrose corn syrup, high fructose corn syrup, and high maltose corn syrup can be utilized as well as the individual sugars listed above. These corn syrups may yield a mix of sugar components for Z. It should be understood that it is by no means intended to exclude other suitable raw materials. Z preferably will be selected from the group consisting of -CH₂-(CH0H)_n-CH₂0H, -CH(CH₂0H)-(CH0H)_n.₁-CH₂0H, -CH₂-(CHOH)2(CHOR')(CHOH)-CH2θH, where n is an integer from 3 to 5, inclusive, and R' is H or a cyclic mono- or poly- saccharide, and alkoxylated derivatives thereof. Most preferred are glycityls wherein n is 4, particularly -CH₂-(CH0H)₄-CH₂0H.

In Formula (I), R¹ can be, for example, N-methyl, N-ethyl, N-propyl, N-isopropyl, N-butyl, N-isobutyl, N-2-hydroxy ethyl, or N-2-hydroxy propyl .

R²-C0-N< can be, for example, cocamide, stearamide, oleamide, laura ide, myristamide, capricamide, palmitamide, tallowamide, etc.

Z can be 1-deoxyglucityl, 2-deoxyfructityl, 1-deoxymaltityl , 1-deoxylactityl, 1-deoxygalactityl, 1-deoxymannityl, 1-deoxymalto- triotityl, etc. The following reactants, catalysts and solvents can conven¬ iently be used in the R-2 reaction herein, and are listed only by way of exemplification and not by way of limitation. Such materials are all well-known and are routinely available from a variety of commercial sources. Reactants - Various fatty esters can be used in the R-2 reaction, including mono-, di- and tri-esters (i.e., triglycer¬ ides). Methyl esters, ethyl esters, and the like are all quite suitable. The polyhydroxyamine reactants include reactants available from the above-described R-l reaction, such as N-alkyl and N-hydroxyalkyl polyhydroxyamines with the N-substituent group such as CH₃-, C₂H₅-, C₃H₇-, H0CH₂CH₂-, and the like. (Polyhy- droxyamines available from the R-l reaction are preferably not contaminated by the presence of residual amounts of metallo hydrogenation catalysts, although a few parts per million [e.g., 1-20 ppm] can be present.) Mixtures of the ester and mixtures of the polyhydroxyamine reactants can also be used.

Catalysts - The catalysts used in the R-2 reaction are basic materials such as the alkoxides (preferred), hydroxides (less preferred due to possible hydrolysis reactions), carbonates, and the like. Preferred alkoxide catalysts include the alkali metal C_x-C₄ alkoxides such as sodium ethoxide, potassium ethoxide, and the like. The catalysts can be prepared separately from the reaction mixture, or can be generated in situ using an alkali metal such as sodium. For in situ generation, e.g., sodium metal in the methanol solvent, it is preferred that the other reactants not be present until catalyst generation is complete. The catalyst typically is used at a level of about 5 mole % of the ester reactant. Mixtures of catalysts can also be used.

Solvents -The organic hydroxy solvents used in the R-2 reaction include, for example, methanol, ethanol, propanol, iso-propanol, the butanols, glycerol, 1,2-propylene glycol, 1,3-propylene glycol, and the like. Methanol is a preferred alcohol solvent and 1,2-propylene glycol is a preferred diol solvent. Mixtures of solvents can also be used.

General R-2 Reaction Conditions - It is an objective herein to prepare the desired products while minimizing the formation of cyclized by-products, . ester amides and color bodies.. Reaction temperatures below about 135^*C, typically in the range of from about 40'C to about 100'C, preferably 50'C to 80'C, are used to achieve this objective, especially in batch processes where reaction times are typically on the order of about 0.5-2 hours, or even up to 6 hours. Somewhat higher temperatures can be tolerated in continuous processes, where residence times can be shorter.

The following examples are intended to illustrate the practice of the R-2 reaction using the N-polyhydroxyamines prepared by the above-disclosed R-l reaction (with H₂0 having been substantially removed), but are not intended to be limiting thereof. It is pointed out that the concentration ranges of the reactants and solvent in Example III provide what can be termed a

"70% concentrated" (with respect to reactants) reaction mixture.

^• This 70% concentrated mixture provides good results, in that high yields of the desired polyhydroxy fatty acid amide product are secured rapidly. Indeed, indications are that the reaction is substantially complete within one hour, or less. The consistency of the reaction mixture at the 70% concentration level provides ease of handling. However, even better results are secured at the 80% and 90% concentration levels, in that chromotography data indicate that even less of the undesired by-products are formed at these higher concentrations. At the higher concentrations the reaction systems are somewhat more difficult to work with, and require more efficient stirring (due to their initial thickness), and the like, at least in the early stages of the reaction. Once the reaction proceeds to any appreciable extent, the viscosity of the reaction system decreases and ease of mixing increases.

EXAMPLE HI The product of Example I (9.00 g, 0.0461 moles, N-methyl¬ glucamine) is combined with 8.22 g methanol anhydrous in a round bottom flask fitted with condenser, drying tube and argon blanket. The reaction methanol and N-methylglucamine are heated to reflux for 15 minutes. Sodium methoxide (0.1245 g, 0.0023 moles, Aldrich Chemical Company) and methyl ester (10.18 g, 0.0461 moles, Procter & Gamble CE1270, includes C_X2-C₁₈ fatty acid esters) are added and reaction continued at reflux for 3 hours. Methanol is then removed under reduced pressure to give essentially colorless white product. Yields are not reported since samples were taken during reaction at 30 minutes, 1 hour, 2 hours and 3 hours before drying. The dried sample is washed with cold methanol and filtered and final drying is done under vacuum to give 10.99 g of the poly¬ hydroxy fatty acid amide detergent.

EXAMPLE IV An overall process at the 80% reactant concentration level for the amide synthesis is as follows.

A reaction mixture consisting of 84.87 g. fatty acid methyl ester (source: Procter & Gamble methyl ester CE1270), 75 g. N-methylglucamine per Example I, above, 1.04 g. sodium methoxide and a total of 39.96 g. methyl alcohol (ca. 20% by wt. of reaction mixture) is used. The reaction vessel comprises a standard reflux set-up fitted with a drying tube, condenser and mechanical stirring blade. The N-methyl gluca ine/methanol is heated with stirring under argon (reflux). After the solution has reached the desired temperature, the ester and sodium methoxide catalyst are added. The reaction mixture is maintained at reflux for 6 hours. The reaction is essentially complete in 1.5 hours. After removal of the methanol, the recovered product weighs 105.57 grams. Chromatography indicates the presence of only traces of undesired ester-amide by-products, and no detectable cyclized by-product.

EXAMPLE V The process of Example IV is repeated at the 90% reactant level for the polyhydroxy fatty acid amide synthesis step. Levels of undesirable by-products are extremely low, and reaction is essentially complete at 30 minutes. In an alternate mode, the reaction can be initiated at a 70% reactant concentration, for example, and methanol can be stripped during the course of the reaction and the reaction taken to completion.

EXAMPLE VI The process of Example III is repeated in ethanol (99%) and 1,2-propylene glycol (essentially dry), respectively, with good product formation. In an alternate mode, a solvent such as 1,2-propylene glycol is used in the R-2 step, with methanol stripping throughout the process. The resulting surfactant/glycol mix can be used directly in a detergent composition.

Having thus disclosed reaction conditions involving amine solvents in the R-l step of- the instant process, it has now further been determined that mixtures of amine/water solvents for use in R-l affords still additional advantages in the R-l reaction. In particular, the use of an amine/water solvent: yields substantially no color formation in the reaction products; gives high product yields relatively quickly; and leaves essentially no reducing sugars in the reaction product, which can contribute to color formation in the subsequent R-2 reaction. The R-l reaction in a mixed amine/water solvent is as follows.

EXAMPLE VII Using a stirred autoclave and procedure per Example II, 15 g of the 649B catalyst, glucose powder (75 g; Aldrich) and 160 mis methanol are slurried and treated with H₂ to remove oxide from the catalyst surface. Methanol is removed. 80 is (52.8 g) of methyl amine are added to the glucose/catalyst mixture at below 5^*C, and 22 is water are added at room temperature. The reaction mixture is heated to 70^*C in 34 minutes and held at 70^*C for 40 minutes, during the hydrogenation. The H₂0/methyl amine solution of the reaction product is blown out of the reactor through the frit (removes catalyst) and dried to yield the N-methylglucamine product.

When using the mixed amine/water solvent, weight ratios of amine (especially, methyl amine) and water in a range of from about 10:1 to about 1:1 are typically employed. The R-l reaction product, substantially free from water (preferably, less than about 1%, more preferably, less than about 0.3% by weight of water) can then be used in the R-2 reaction to prepare polyhydroxy fatty acid amides, as described above. While the foregoing disclosure generally relates to a solvent-assisted method for preparing N-methyl polyhydroxy amines, such as N-methyl glucamine, as well as their fatty acid amide derivatives using fatty methyl esters, it is to be understood that variations are available which do not depart from the spirit and scope of this invention. Thus, reducing sugars such as fructose, galactose, mannose, maltose and lactose, as well as sugar sources such as high dextrose corn syrup, high fructose corn syrup and high maltose corn syrup, and the like, can be used, to prepare the polyhydroxyamine material (i.e., to replace glucamine) of the reaction. Likewise, a wide variety of fats and oils (triglycer¬ ides) can be used herein in place of the fatty esters exemplified above. For example, fats and oils such as soybean oil, cottonseed oil, sunflower oil, tallow, lard, safflower oil, corn oil, canola oil, peanut oil, fish oil, rapeseed oil, and the like, or hardened (hydrogenated) forms thereof, can be used as the source of tri- glyceride esters for use in the present process. It will be appreciated that the manufacture of detersive surfactants from such renewable resources is an important advantage of the present process. The present process is particularly useful when prepar- ing the longer-chain (e.g., C_lβ) and unsaturated fatty acid polyhydroxy amides, since the relatively mild reaction temperatures and conditions herein afford the desired products with minimal by-product formation. A pre-formed portion of the polyhydroxy fatty acid amide surfactant can be used to assist initiation of the R-2 amide-forming reaction when triglycerides or the longer-chain methyl esters are used as reactants. Furthermore, use of propylene glycol, or glycerine, or preformed mono esters thereof, can assist in initiation of the R-2 reaction, as well. It has further been determined that surfactant yields in the R-2 process can be increased by simply storing the solidified product (which contains some minor amount of entrained solvent and reactants) e.g., at 50'C, for a few hours after removal from the reaction vessel. Storage in this manner apparently allows the last fraction of unreacted starting materials to continue to form the desired polyhydroxy fatty acid amide surfactant. Thus, yields can be increased appreciably, i.e., to a high degree of completion, which is an important consideration in large-scale industrial processes.

The invention encompasses the use of the above-described surfactant products of the overall R-l plus R-2 process to prepare fully-formulated detergent compositions using a wide variety of surfactants, builders and optional detersive adjuncts and other ingredients well-known to detergent formulators can be used in such compositions, all at conventional usage levels. Accordingly, the present invention also encompasses a process for preparing a fully-formulated laundry detergent composition, or the like, comprising admixing the solvent-containing reaction product of the polyhydroxy fatty acid amide-forming R-2 reaction with otherwise conventional detersive surfactants and detersive adjuncts.

The following is not intended to limit the invention herein, but is simply to further illustrate additional aspects of the technology which may be considered by the formulator in the manufacture of a wide variety of detergent compositions using the polyhydroxy fatty acid amides.

It will be readily appreciated that the polyhydroxy fatty acid amides are, by virtue of their amide bond, subject to some instability under highly basic or highly acidic conditions. While some decomposition can be tolerated, it is preferred that these materials not be subjected to pH's above about 11, preferably 10, nor below about 3 for unduly extended periods. Final product pH (liquids) is typically 7.0-9.0 and up to about 10.5 or 11 for solids. During the manufacture of the polyhydroxy fatty acid amides it will typically be necessary to at least partially neutralize the base catalyst used to form the amide bond. While any acid can be used for this purpose, the detergent formulator will recognize that it is a simple and convenient matter to use an acid which provides an anion that is otherwise useful and desirable in the finished detergent composition. For example, citric acid can be used for purposes of neutralization and the resulting citrate ion (ca. 1%) be allowed to remain with a ca. 40% polyhydroxy fatty acid amide slurry and be pumped into the later manufacturing stages of the overall detergent-manufacturing process. The acid forms of materials such as oxydisuccinate, nitrilotriacetate, ethylenediaminetetraacetate, tartrate/succinate, and the like, can be used similarly.

The polyhydroxy fatty acid amides derived from coconut alkyl fatty acids (predominantly C₁₂-C₁₄) are more soluble than their tallow alkyl (predominantly C₁₆-C_lβ) counterparts. Accordingly, the C₁₂-C₁₄ materials are somewhat easier to formulate in liquid compositions, and are more soluble in cool-water laundering baths. However, the C_I6-C₁₈ materials are also quite useful, especially under circumstances where warm-to-hot wash water is used. Indeed, the C₁₆-C₁₈ materials may be better detersive surfactants than their C₁₂-C₁₄ counterparts. Accordingly, the formulator may wish to balance ease-of- anufacture vs. performance when selecting a particular polyhydroxy fatty acid amide for use in a given formulation.

It will also be appreciated that the solubility of the polyhydroxy fatty acid amides can be increased by having points of unsaturation and/or chain branching in the fatty acid moiety. Thus, materials such as the polyhydroxy fatty acid amides derived from oleic acid and iso-stearic acid are more soluble than their n-alkyl counterparts.

Likewise, the solubility of polyhydroxy fatty acid amides prepared from disaccharides, trisaccharides, etc., will ordinarily be greater than the solubility of their monosaccharide-derived counterpart materials. This higher solubility can be of particular assistance when formulating liquid compositions. Moreover, the polyhydroxy fatty acid amides wherein the polyhydroxy group is derived from maltose appear to function especially well as detergents when used in combination with conventional alkylbenzene sulfonate ("LAS") surfactants. While not intending to be limited by theory, it appears that the combination of LAS with the polyhydroxy fatty acid amides derived from the higher saccharides such as maltose causes a substantial and unexpected lowering of interfacial tension in aqueous media, thereby enhancing net detergency performance. (The manufacture of a polyhydroxy fatty acid amide derived from maltose is described hereinafter.)

The polyhydroxy fatty acid amides can be manufactured not only from the purified sugars, but also from hydrolyzed starches, e.g., corn starch, potato starch, or any other convenient plant- derived starch which contains the mono-, di-, etc. saccharide desired by the formulator. This is of particular importance from the economic standpoint. Thus, "high glucose" corn syrup, "high maltose" corn syrup, etc. can conveniently and economically be used. De-lignified, hydrolyzed cellulose pulp can also provide a raw material source for the polyhydroxy fatty acid amides.

As noted above, polyhydroxy fatty acid amides derived from the higher saccharides, such as maltose, lactose, etc., are more soluble than their glucose counterparts. Moreover, it appears that the more soluble polyhydroxy fatty acid amides can help solubilize their less soluble counterparts, to varying degrees. Accordingly, the formulator may elect to use a raw material comprising a high glucose corn syrup, for example, but to select a syrup which contains a modicum of maltose (e.g., 1% or more). The resulting mixture of polyhydroxy fatty acids will, in general, exhibit more preferred solubility properties over a broader range of temperatures and concentrations than would a "pure" glucose- derived polyhydroxy fatty acid amide. Thus, in addition to any economic advantages for using sugar mixtures rather than pure sugar reactants, the polyhydroxy fatty acid amides prepared from mixed sugars can offer very substantial advantages with respect to performance and/or ease-of-formulation. In some instances, however, some loss of grease removal performance (dishwashing) may be noted at fatty acid maltamide levels above about 25% and some loss in sudsing above about 33% (said percentages being the percentage of maltamide-derived polyhydroxy fatty acid amide vs. glucose-derived polyhydroxy fatty acid amide in the mixture). This can vary somewhat, depending on the chain length of the fatty acid moiety. Typically, then, the formulator electing to use such mixtures may find it advantageous to select polyhydroxy fatty acid amide mixtures which contain ratios of monosaccharides (e.g., glucose) to di- and higher saccharides (e.g., maltose) from about 4:1 to about 99:1. It has now been determined that it may be convenient for the formulator of, for example, liquid detergents to conduct such processes in 1,2-propylene glycol solvent, since the glycol solvent need not be completely removed from the reaction product prior to use in the finished detergent formulation. Likewise, the formulator of, for example, solid, typically granular, detergent compositions may find it convenient to run the process at 30'C- 90^βC in solvents which comprise alkoxylated, especially ethoxyl¬ ated, alcohols, such as the ethoxylated (EO 3-8) C₁₂-C₁₄ alcohols, such as those available as NEODOL 23 E06.5 (Shell). When such ethoxylates are used, it is preferred that they not contain substantial amounts of unethoxylated alcohol and, most preferably, not contain substantial amounts of mono-ethoxylated alcohol.

Typically, the industrial scale reaction sequence for preparing the preferred acyclic polyhydroxy fatty acid amides will comprise: Step 1 - preparing the N-alkyl polyhydroxy amine derivative from the desired sugar or sugar mixture by formation of an adduct of the N-alkyl amine and the sugar, followed by reaction with hydrogen in the presence of a catalyst; followed by Step 2 - reacting the aforesaid polyhydroxy amine with, preferably, a fatty ester to form an amide bond. While a variety of N-alkyl polyhy¬ droxy amines useful in Step 2 of the reaction sequence can be prepared by various art-disclosed processes, the following process is convenient and makes use of economical sugar syrup as the raw material. It is to be understood that, for best results when using such syrup raw materials, the manufacturer should select syrups that are quite light in color or, preferably, nearly colorless ("water-white").

Preparation of N-Alkyl Polyhydroxy Amine

From Plant-Derived Sugar Syrup I. Adduct Formation - The following is a standard process in which about 420 g of about 55% glucose solution (corn syrup - about 231 g glucose - about 1.28 moles) having a Gardner Color of less than 1 is reacted with about 119 g of about 50% aqueous methyla ine (59.5 g of methyla ine - 1.92 moles) solution. The methylamine (MMA) solution is purged and shielded with N₂ and cooled to about 10^*C, or less. The corn syrup is purged and shielded with N₂ at a temperature of about 10'-20'C. The corn syrup is added slowly to the MMA solution at the indicated reaction temperature as shown. The Gardner Color is. measured at the indicated approximate times in minutes.

TABLE 1

As can be seen from the above data, the Gardner Color for the adduct is much worse as the temperature is raised above about 30'C and at about 50'C, the time that the adduct has a Gardner Color below 7 is only about^* 30 minutes. For longer reaction, and/or holding times, the temperature should be less than about 20'C. The Gardner Color should be less than about 7, and preferably less than about 4 for good color glucamine.

When one uses lower temperatures for forming the adduct, the time to reach substantial equilibrium concentration of the adduct is shortened by the use of higher ratios of amine to sugar. With the 1.5:1 mole ratio of amine to sugar noted, equilibrium is reached in about two hours at a reaction temperature of about 30'C. At a 1.2:1 mole ratio, under the same conditions, the time is at least about three hours. For good color, the combination of amine:sugar ratio; reaction temperature; and reaction time is selected to achieve substantially equilibrium conversion, e.g., more than about 90%, preferably more than about 95%, even more preferably more than about 99%, based upon the sugar, and a color that is less than about 7, preferably less than about 4, more preferably less than about 1, for the adduct.

Using the above process at a reaction temperature of less than about 20'C and corn syrups with different Gardner Colors as indicated, the MMA adduct color (after substantial equilibrium is reached in at least about two hours) is as indicated.

TABLE 2 Gardner Color IApproximate) Corn syrup 1 1 1 1+ 0 0 0+

Adduct 3 4/5 7/8 7/8 1 2 1

As can be seen from the above, the starting sugar material must be very near colorless in order to consistently have adduct that is acceptable. When the sugar has a Gardner Color of about 1, the adduct is sometimes acceptable and sometimes not accept¬ able. When the Gardner Color is above 1 the resulting adduct is unacceptable. The better the initial color of the sugar, the better is the color of the adduct.

II. Hvdroaen Reaction - Adduct from the above having a Gardner Color of 1 or less is hydrogenated according to the following procedure.

About 539 g of adduct in water and about 23.1 g of United Catalyst G49B Ni catalyst are added to a one liter autoclave and purged two times with 200 psig H₂ at about 20'C. The H₂ pressure s raised to about 1400 psi and the temperature is raised to about 50'C. The pressure is then raised to about 1600 psig and the temperature is held at about 50-55'C for about three hours. The product is about 95% hydrogenated at this point. The temperature is then raised to about 85'C for about 30 minutes and the reaction mixture is decanted and the catalyst is filtered out. The product, after removal of water and MMA by evaporation, is about 95% N-methyl glucamine, a white powder.

The above procedure is repeated with about 23.1 g of Raney Ni catalyst with the following changes. The catalyst is washed three times and the reactor, with the catalyst in the reactor, is purged twice with 200 psig H₂ and the reactor is pressurized with H₂ at 1600 psig for two hours, the pressure is released at one hour and the reactor is repressurized to 1600 psig. The adduct is then pumped into the reactor which is at 200 psig and 20'C, and the reactor is purged with 200 psig H₂, etc., as above.

The resulting product in each case is greater than about 95% N-methyl glucamine; has less than about 10 ppm Ni based upon the glucamine; and has a solution color of less than about Gardner 2. The crude N-methyl glucamine is color stable to about 140^βC for a short exposure time.

It is important to have good adduct that has low sugar content (less than about 5%, preferably less than about 1%) and a good color (less than about 7, preferably less than about 4 Gardner, more preferably less than about 1).

In another reaction, adduct is prepared starting with about 159 g of about 50% methylamine in water, which is purged and shielded with N₂ at about 10-20'C. About 330 g of about 70% corn syrup (near water-white) is degassed with N₂ at about 50'C and is added slowly to the methylamine solution at a temperature of less than about 20'C. The solution is mixed for about 30 minutes to give about 95% adduct that is a very light yellow solution.

About 190 g of adduct in water and about 9 g of United Catalyst G49B Ni catalyst are added to a 200 ml autoclave and purged three times with H₂ at about 20'C. The H₂ pressure is raised to about 200 psi and the temperature is raised to about 50'C. The pressure is raised to 250 psi and the temperature is held at about 50-55'C for about three hours. The product, which is about 95% hydrogenated at this point, is then raised to a temperature of about 85'C for about 30 minutes and the product, after removal of water and evaporation, is about 95% N-methyl glucamine, a white powder.

It is also important to minimize contact between adduct and catalyst when the H₂ pressure is less than about 1000 psig to minimize Ni content in the glucamine. The nickel content in the

N-methyl glucamine in this reaction is about 100 ppm as compared to the less than 10 ppm in the previous reaction.

The following reactions with H₂ are run for direct comparison of reaction temperature effects.

A 200 ml autoclave reactor is used following typical pro¬ cedures similar to those set forth above to make adduct and to run the hydrogen reaction at various temperatures.

Adduct for use in making glucamine is prepared by combining about 420 g of about 55% glucose (corn syrup) solution (231 g glucose; 1.28 moles) (the solution is made using 99DE corn syrup from CarGill, the solution having a color less than Gardner 1) and about 119 g of 50% methylamine (59.5 g MMA; 1.92 moles) (from Air Products). The reaction procedure is as follows: 1. Add about 119 g of the 50% methylamine solution to a N₂ purged reactor, shield with N₂ and cool down to less than about lO'C. 2. Degas and/or purge the 55% corn syrup solution at 10-20^βC with N₂ to remove oxygen in the solution.

3. Slowly add the corn syrup solution to the methylamine solution and keep the temperature less than about 20'C.

4. Once all corn syrup solution is added in, agitate for about 1-2 hours.

The adduct is used for the hydrogen reaction right after making, or is stored at low temperature to prevent further degradation.

The glucamine adduct hydrogen reactions are as follows: 1. Add about 134 g adduct (color less than about Gardner 1) and about 5.8 g G49B Ni to a 200 ml autoclave.-

2. Purge the reaction mix with about 200 psi H₂ twice at about 20-30'C.

3. Pressure with H₂ to about-400 psi and raise the temperature to about 50'C.

4. Raise pressure to about 500 psi, react for about 3 hours. Keep temperature at about 50-55'C. Take Sample 1.

5. Raise temperature to about 85'C for about 30 minutes.

6. Decant and filter out the Ni catalyst. Take Sample 2. Conditions for constant temperature reactions:

1. Add about 134 g adduct and about 5.8 g G49B Ni to a 200 ml autoclave.

2. Purge with about 200 psi H₂ twice at low temperature.

3. Pressure with H₂ to about 400 psi and raise temperature to about 50'C.

4. Raise pressure to about 500 psi, react for about 3.5 hours. Keep temperature at indicated temperature.

5. Decant and filter out the Ni catalyst. Sample 3 is for about 50-55'C; Sample 4 is for about 75'C; and Sample 5 is for about 85'C. (The reaction time for about 85'C is about 45 minutes.)

All runs give similar purity of N-methyl glucamine (about 4%); the Gardner Colors of the runs are similar right after reaction, but only the two-stage heat treatment gives good color stability; and the 85'C run gives marginal color immediately after reaction.

EXAMPLE VIII The preparation of the tallow (hardened) fatty acid amide of N-methyl maltamine for use in detergent compositions according to this invention is as follows.

Step 1 - Reactants: Maltose monohydrate (Aldrich, lot 01318KW); methylamine (40 wt% in water) (Aldrich, lot 03325TM); Raney nickel, 50% slurry (UAD 52-73D, Aldrich, lot 12921LW).

The reactants are added to glass liner (250 g maltose, 428 g methylamine solution, 100 g catalyst slurry - 50 g Raney Ni) and placed in 3 L rocking autoclave, which is purged with nitrogen (3X500 psig) and hydrogen (2X500 psig) and rocked under H₂ at room temperature over a weekend at temperatures ranging from 28^*C to 50'C. The crude reaction mixture is vacuum filtered 2X through a glass microfiber filter with a silica gel plug. The filtrate is concentrated to a viscous material. The final traces of water are azetroped off by ^"dissolving the material in methanol and then removing the methanol/water on a rotary evaporator. Final drying is done under high vacuum. The crude product is dissolved in refluxing methanol, filtered, cooled to recrystallize, filtered and the filter cake is dried under vacuum at 35'C. This is cut #1. The filtrate is concentrated until a precipitate begins to form and is stored in a refrigerator overnight. The solid is filtered and dried under vacuum. This is cut #2. The filtrate is again concentrated to half its volume and a recrystallization is performed. Very little precipitate forms. A small quantity of ethanol is added and the solution is left in the freezer over a weekend. The solid material is filtered and dried under vacuum. The combined solids comprise N-methyl maltamine which is used in Step 2 of the overall synthesis.

Step 2 - Reactants: N-methyl maltamine (from Step 1); hardened tallow methyl esters; sodium methoxide (25% in methanol); absolute methanol (solvent); mole ratio 1:1 amine:ester; initial catalyst level 10 mole % (w/r maltamine), raised to 20 mole %; solvent level 50% (wt.). In a sealed bottle, 20.36 g of the tallow methyl ester is heated to its melting point (water bath) and loaded into a 250 ml 3-neck round-bottom flask with mechanical stirring. The flask is heated to ca. 70'C to prevent the ester from solidifying. Separately, 25.0 g of N-methyl maltamine is combined with 45.36 g of methanol, and the resulting slurry is added to the tallow ester with good mixing. 1.51 g of 25% sodium methoxide in methanol is added. After four hours the reaction mixture has not clarified, so an additional 10 mole % of catalyst (to a total of 20 mole %) is added and the reaction is allowed to continue overnight {ca . 68'C) after which time the mixture is clear. The reaction flask is then modified for distillation. The temperature is increased to llO'C. Distillation at atmospheric pressure is continued for 60 minutes. High vacuum distillation is then begun and continued for 14 minutes, at which time the product is very thick. The product is allowed to remain in the reaction flask at 110'C (external temperature) for 60 minutes. The product is scraped from the flask and triturated in ethyl ether over a weekend. Ether is removed on a rotary evaporator and the product is stored in an oven overnight, and ground to a powder. Any remaining N-methyl maltamine is removed from the product using silica gel. A silica gel slurry in 100% methanol is loaded into a funnel and washed several times with 100% methanol. A concentrated sample of the product (20 g in 100 ml of 100% methanol) is loaded onto the silica gel and eluted several times using vacuum and several methanol washes. The collected eluant is evaporated to dryness (rotary evaporator). Any remaining tallow ester is removed by trituration in ethyl acetate overnight, followed by filtration. The filter cake is then vacuum dried overnight. The product is the tallowalkyl N-methyl maltamide.

In an alternate mode, Step 1 of the foregoing reaction sequence can be conducted using commercial corn syrup comprising glucose or mixtures of glucose and, typically, 5%, or higher, maltose. The resulting polyhydroxy fatty acid amides and mixtures can be used in any of the detergent compositions herein.

In still another mode, Step 2 of the foregoing reaction sequence can be carried out in 1,2-propylene glycol or NEODOL. At the discretion of the formulator, the propylene glycol or NEODOL need not be removed from the reaction product prior to its use to formulate detergent compositions. Again, according to the desires of the formulator, the methoxide catalyst can be neutralized by citric acid to provide sodium citrate, which can remain in the polyhydroxy fatty acid amide.

For cleaning compositions where especially high sudsing is desired (e.g., dishwashing), it is preferred that less than about 5%, more preferably less than about 2%, most preferably no C₁₄ or higher fatty acid be present. Accordingly, preferred polyhydroxy fatty acid amide compounds and mixtures prepared by the present invention are preferably substantially free of suds-suppressing amounts of C₁₄ and higher fatty acids. If some fatty acid is unavoidably present, commercially-available amine oxide and/or sulfobetaine (aka "sultaine") surfactants can be used with the polyhydroxy fatty acid amides to at least partially overcome some of the negative sudsing effects. Alternatively, the polyhydroxy fatty acid amide can be prepared using fatty acid esters primarily of chain lengths lower than C₁ , especially C₁₂ fatty methyl esters. The polyhydroxy fatty acid amides provided herein are useful in both solid and liquid detergent compositions, which can also contain known detersive surfactants, enzymes, builders, soil release polymers and other detersive adjuncts quite well-known to the skilled artisan. The formulator wishing to add anionic optical brighteners to liquid detergents containing relatively high concentrations (e.g., 10% and greater) of anionic or poly- anionic substituents such as the polycarboxylate builders may find it useful to pre-mix the brightener with water and the polyhydroxy fatty acid amide, and then to add the pre-mix to the final composition.

It will be appreciated by those skilled in the chemical arts that the preparation of the polyhydroxy fatty acid amides herein using the di- and higher saccharides such as maltose will result in the formation of polyhydroxy fatty acid amides wherein linear substituent Z is "capped" by a polyhydroxy ring structure. Such materials are fully contemplated for use herein and do not depart from the spirit and scope of the invention as disclosed and claimed.

Claims

1. A process carried out under non-oxidizing conditions for preparing N-alkyl polyhydroxy amines, comprising the steps of: a) reacting a reducing sugar or reducing sugar derivative with a C.-C alkyl or hydroxyal yl primary amine reactant in an ctmine solvent at mole ratios of aminersugar not greater than 30:1 to provide an adduct; b) reacting said adduct from step (a) dissolved in said solvent with hydrogen under mild conditions in the presence of a metal catalyst; and c) removing said catalyst and substantially removing water and unreacted amines from the reaction mixture to secure the N-alkyl polyhydroxy amine.

2. A process according to Claim 1 wherein the sugar is glucose, maltose or mixtures of glucose and maltose.

3. A process according to Claim 2 wherein the amine reactant and amine solvent are both monctmethyl amine, whereby N-methylgluca¬ mine, N-metJiylmaltemine, or mixtures thereof, is secured.

4. A process according to Claim 1 wherein the metal catalyst is a particulate catalyst cσmprising nickel on a substrate material.

5. A process according to Claim 1 wherein the solvent comprises a mixture of amine and water.

6. A process for preparing polyhydroxy fatty acid amide surfactants, cc prisirig: providing a polyhydroxyamine reaction product in the manner of Claim 1, and reacting said polyhydroxya¬ mine product with a fatty acid ester in an organic hydroxy or alkoxy solvent in the presence of a base catalyst to form the polyhydroxy fatty acid amide surfactant, and, optionally, removing said hydroxy or alkoxy solvent. preparing N-alkyl polyhydroxy amines, coπprising reacting an N-alkyl primary amine reactant with a reducing sugar reactant and hydrogen in a reaction solvent cx-mprising an excess of said N-alkyl primary amine and water, said reaction with hydrogen being carried out in the presence of a metal catalyst.

8. A process aα^ording to Claim 7 wherein the reaction solvent comprises said N-alkyl r^irnary amine and water at a weight ratio of from 10:1 to 1:1.

9. A process according to Claim δ wherein the primary amine reactant is methyl amine and the sugar is glucose or maltose, whereby N***methylglucamine or N***methy.l_ιιalta_mirø is secured.

10. A process according to Claim 9 wherein the catalyst comprises nickel on a substrate material.

11. A process according to Claim 7 wherein the sugar is derived from a plant source and comprises glucose and maltose at a weight ratio of glucose:maltose from 4:1 to 99:1.