CA1273141A - Process for the preparation of polyoxyalkylene block polyethers having enhanced properties - Google Patents
Process for the preparation of polyoxyalkylene block polyethers having enhanced propertiesInfo
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- CA1273141A CA1273141A CA000552223A CA552223A CA1273141A CA 1273141 A CA1273141 A CA 1273141A CA 000552223 A CA000552223 A CA 000552223A CA 552223 A CA552223 A CA 552223A CA 1273141 A CA1273141 A CA 1273141A
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- Prior art keywords
- cesium
- hydroxide
- cesium hydroxide
- containing catalyst
- oxide
- Prior art date
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- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
- C08G65/00—Macromolecular compounds obtained by reactions forming an ether link in the main chain of the macromolecule
- C08G65/02—Macromolecular compounds obtained by reactions forming an ether link in the main chain of the macromolecule from cyclic ethers by opening of the heterocyclic ring
- C08G65/26—Macromolecular compounds obtained by reactions forming an ether link in the main chain of the macromolecule from cyclic ethers by opening of the heterocyclic ring from cyclic ethers and other compounds
- C08G65/2642—Macromolecular compounds obtained by reactions forming an ether link in the main chain of the macromolecule from cyclic ethers by opening of the heterocyclic ring from cyclic ethers and other compounds characterised by the catalyst used
- C08G65/2645—Metals or compounds thereof, e.g. salts
- C08G65/2648—Alkali metals or compounds thereof
Abstract
PROCESS FOR THE PREPARATION OF
POLYOXYALKYLENE BLOCK POLYETHERS HAVING ENHANCED PROPERTIES
Abstract of the Disclosure Polyoxyalkylene block polyether polyols having enhanced physical properties are prepared by catalyzing the ethylene oxide addition with cesium hydroxide or mixtures of cesium hydroxide with other basic catalysts. There poly-ethers are especially useful in surface active applications.
POLYOXYALKYLENE BLOCK POLYETHERS HAVING ENHANCED PROPERTIES
Abstract of the Disclosure Polyoxyalkylene block polyether polyols having enhanced physical properties are prepared by catalyzing the ethylene oxide addition with cesium hydroxide or mixtures of cesium hydroxide with other basic catalysts. There poly-ethers are especially useful in surface active applications.
Description
~27314~
PROCESS FOR THE PREPARATION OF
POLYOXYALKYLENE BLOCK POLYETHERS HAVING ENHA~'~E~ PROPERTIES
Background of the Invention 1. Field of the Invention The subject invention relates to a process for the preparation of polyoxyalkylene block polyether~. More particularly, the invention relates to a proces~ for the preparation of block polyoxyalkylene polyethers having one or more polyoxyethylene block3 and at least one block derived from a higher alkylene oxide. The use of cesium hydroxide to catalyze the oxyethylation reqults in poly-ether~ having enhanced propertie~.
PROCESS FOR THE PREPARATION OF
POLYOXYALKYLENE BLOCK POLYETHERS HAVING ENHA~'~E~ PROPERTIES
Background of the Invention 1. Field of the Invention The subject invention relates to a process for the preparation of polyoxyalkylene block polyether~. More particularly, the invention relates to a proces~ for the preparation of block polyoxyalkylene polyethers having one or more polyoxyethylene block3 and at least one block derived from a higher alkylene oxide. The use of cesium hydroxide to catalyze the oxyethylation reqults in poly-ether~ having enhanced propertie~.
2. De~cription of the Related Art Polyoxyalkylene block polyether~ are well known commercial products having many uses, the most important of which i~ their uqe a~ nonionic surfactantq. Polyoxyalkylene block polyether surfactants generally have both hydrophobic and hydrophilic blocks, and are described, for example, by Lundsted in U.S. Patent 2,674,619 and by Jackson and Lundsted in U.S. Patents 2,677,700 and 3,036,118. The~e references also disclo~e the preparation of ouch polyoxy-alkylene block polyethers by oxypropylating an initiator molecule po~seq~ing two or more active hydrogens in the pre~ence of a basic cataly~t ~uch a~ qodium or pota~ium hydroxide. The polyoxypropylene hydrophobe is then oxy-`~k i273i4~l ethylated to produce external hydrophileq, or, in certain cases, the oxypropylation and oxyethylation may be rever~ 3 to produce "reverse" non-ionic surfactantq having an internal hydrophile and external hydrophobeR.
Diblock polyoxyalkylene polyethers or triblock polyoxyalkylene polyetherq capped on one end are also u~eful products. These product~ are generally prepared by ~equen-tially oxyalkylating a monofunctional initiator molecule such as an alkanol or phenol. To prepare diblock polyethers by this method, the initiator i8 firBt reacted with a higher alkylene oxide, that is, one having three or more carbons.
The re~ulting hydrophobe i9 then oxyethylated. In certain applications the oxyalkylation may be reversed. Triblock polyethers are ~i~ilarly prepared, but with a third oxy-alkylation utilizing the same alkylene oxide as used for the first oxyalkylation.
For example, a triblock polyoxyalkylene polyether may be conventionally prepared, as ~hown in the reaction scheme below, by fir~t oxypropylating a difunctional initiator molecule followed by oxyethylation. In these reaction schemes, -OP- and -PO- represent oxypropyl re3idueq derived from propylene oxide while -OE- and -EO- represent analogouqly derived oxyethyl groups.
~273~1 CH3 o /\
Step 1: HO-CH-CH2-OH +2n CH2-CH-CH3 -_~
propylene glycol propylene oxid,e H ~ OP ~jO-CH-CH2-O ~ PO ~ H
polyoxypropylene hydrophobe CH O
1 3 / \
tep 2: H ~ OP ~ -CH-CH2~--PO ~ H + 2m CH2~H2 ----~
ethylene oxide H~OE~OP~jOCH-CH2 -O~PO~EO~mH -An analogous monofunctional, mono-capped triblock polymer may be prepared by starting with a monol, R-OH, such a~
methanol, butanol, or benzylalcohol and altering the oxyalkylation 3equence as follows:
Step 1: R-OH + m CH -CH ~ R-O-~-EO )~H
Step 2: -t-mH + (2n + 1) CH2-CH-CH
1273~41 R-O ( ~ ~ PO-3-2- IH
Step 3: R-O-~-EO ~ ~n+IH ~ m CH2-CH2 ___~
R-O ( EO ~ PO ~ EO )mH.
Such mono-capped block polyethers where the cap is joined to the block polyether by an ether linkage are hydrolytically ~table and have been ~hown to posses~ different physical and chemical properties as compared to their non-capped ana-logues including modified surface activity and increa~ed thermal stability.
The polyoxyalkylene polyethers described above have proven useful in numerous applications, particularly those requiring surface active properties such as deter-gent~, foaming and defoaming agentA, emulaifying and dispersing agents, and a~ thickeners in aqueous ~y tems.
However, despite their great utility, the method3 of preparation previously de~cribed never results in a single, uniform product molecule, but in a cogeneric mixture containing molecules with widely varying total molecular weights as well as widely varying hydrophobe and hydrophile weights. This is particularly true as the molecular weight~
~73~4'1 increase. Although it is well known that block polyether surfactants having uniform, narrow molecular weights and compo~itions possess properties markedly different fro0 ~hose of ordinary commercial products, it has been impos-sible to prepare such specialty products wi~hout inordinate expense.
It ha3 now been surprisingly discovered that polyoxyalkylene block polyetherq having narrow molecular weight distribution, uniform composition, and unexpectedly low levels of un~aturation may be simply and economically prepared through the use of cesium hydroxide catalysis for at least the oxyethylation portion of the polyether syn-thesi~, and preferably for both oxyethylation and oxypropyl-ation.
The use of cesium hydroxide as a polyoxypropyla-tion catalyst ha~ been proposed in U.S. Patent 3,393,243.
According to this reference, the use of cesium hydroxide as opposed to conventional ~odium or potassium hydroxide catalysts in the synthesis of polyoxypropylene glycols prevents the elimination reaction at the polyether chain terminu~, which ordinarily results in forming allylic unsaturation and, at the same time, lower~ and broadens the molecular weight of the product polyoxypropylene glycols.
A mechanism for the elimination disclo~ed in U.S.
Patent 3,393,243 is discu~sed in Ceresa, Block and Graft 12731~
Copolymerization, vol. 2, published by Wiley-Interscience at page 18. The mechan$sm apparently involve~ hydrogen abstration via a specific cyclic tran3ition state which may be repre~ented as follows:
~0 /\
R-O--~--polyoxyalkylene--~--OCH2-CH lH2 H2 ~ / CH-CH3 o~
R-0 ( polyoxyalkylene--~--OCH2-CH=CH2 + ~3~0 \
f H-CH3 The unsaturation formed increa~es a~ a direct function of equivalent weight. Eventually a point is reached wherein further propylene oxide addition fail~ to increa~e the molecular weight.
When oxyethylation rather than oxypropylation i~
performed, as in the preparation of block polyethers, the use of cesium hydroxide a~ a catalyst ha~ not been contem-plated. The reason for this i~ that while it i~ readily conceived that polyoxypropylene glycols may react by the above mechanism, the ~ame cannot be true for polyoxyethylene glycol~ or for oxyethylated polyoxypropylene glycols containing more than one oxyethyl group. Thus, until now, such block polyether~ have been prepared with le~ expen~ive sodium and pota3~ium hydroxide catalyst3.
For examplè, when a ~ingle oxyethyl group i8 added to a polyoxypropylene glycol, the elimination mechani~m may be written thusly:
~0\
R-0 (--polyoxyalkylene-~-OCH2-CH ICH2 H2C~ ~CH2 o~
R-O ~ polyoxyalkylene ~ OCH2-CH=CH2 + ~ 0\
However, when more than one oxyethyl group i~ present, the requisite transition ~tate cannot be achieved, and thus it had not been thought that the elimination products could affect in the polymerization reaction:
R-O-~-polyoxypropylene~ polyoxyethylene)~CH2-CH2 CH2-->no elimination ~0, ~273~41 Consequently, no elimination, no unsaturation formation, and therefore no lowering of the polyether molecular weight is expected during ethylene oxide addition, and, in fac~, none has been detected heretofore.
Summary of the Invention It has now been surpri~ingly discovered, contrary to previou~ belief, that unsaturation is produced not only during the preparation of polyoxypropylene glycol~ during oxypropylation of a suitable initiator, but is also formed during oxyethylation as well. There is at present no accepted mechani4m which to attribute this formation of unsaturation during ethylene oxide addition. It ha3 further been discovered that cesium hydroxide is effective in lowering the amount of unsaturation formed during ethylene oxide addition and, at the same time, producing block polyethers with narrow molecular weight di~tribution and uniform compoqition.
Description of ths Preferred Embodiments The polyoxyalkylene block polyethers of the qubject invention are prepared in the conventional manner, except that cesium hydroxide is utilized as the oxyalkyla-tion cataly~t rather than the conventional potassium hydroxide or qodium hydroxide catalyqts. Other, ~trongly 12~314~
ba~ic cesium salts, for example cesium methoxide, may also be util;zed. Preferably the catalyst contains, in addition to cesium hydroxide, n~ more than 50 mole percent of other alkali metal hydroxides and more pref~errably, no more than 20 mole percent. Most preferably, pure or technical grade cesium hydroxide alone is utilized.
When the polyoxypropylene or higher alkylene oxide-derived hydrophobe i5 prepared first by oxyalkyklating a mono-, di-, or higher functional initiator such as methanol, butanol, ethylene glycol, propylene glycol, butylene glycol, glycerine, tetrakis (2-hydroxypropyl)-ethylenediamine or the like, potassium hydroxide may be used as the initial oxyalkylation cataly t provided that the hydrophobe is of modest molecular weight, i.e., equivalent weights of less than 2000, preferably less than 1500.
However, in this case, the residual potassium hydroxide catalyst ~8 preferably removed prior to additional oxypropy-lation to higher molecular weights, and, in any case, before oxyethylation. The mechanics of polyether preparation are otherwise conventional and well known to tho~e skilled in the art. Examples of such preparation may be found, for example, in the treati~e by Schick entitled Nonionic Surfac-tants, and in U.S. Patents 2,674,619, 2,677,700, and
Diblock polyoxyalkylene polyethers or triblock polyoxyalkylene polyetherq capped on one end are also u~eful products. These product~ are generally prepared by ~equen-tially oxyalkylating a monofunctional initiator molecule such as an alkanol or phenol. To prepare diblock polyethers by this method, the initiator i8 firBt reacted with a higher alkylene oxide, that is, one having three or more carbons.
The re~ulting hydrophobe i9 then oxyethylated. In certain applications the oxyalkylation may be reversed. Triblock polyethers are ~i~ilarly prepared, but with a third oxy-alkylation utilizing the same alkylene oxide as used for the first oxyalkylation.
For example, a triblock polyoxyalkylene polyether may be conventionally prepared, as ~hown in the reaction scheme below, by fir~t oxypropylating a difunctional initiator molecule followed by oxyethylation. In these reaction schemes, -OP- and -PO- represent oxypropyl re3idueq derived from propylene oxide while -OE- and -EO- represent analogouqly derived oxyethyl groups.
~273~1 CH3 o /\
Step 1: HO-CH-CH2-OH +2n CH2-CH-CH3 -_~
propylene glycol propylene oxid,e H ~ OP ~jO-CH-CH2-O ~ PO ~ H
polyoxypropylene hydrophobe CH O
1 3 / \
tep 2: H ~ OP ~ -CH-CH2~--PO ~ H + 2m CH2~H2 ----~
ethylene oxide H~OE~OP~jOCH-CH2 -O~PO~EO~mH -An analogous monofunctional, mono-capped triblock polymer may be prepared by starting with a monol, R-OH, such a~
methanol, butanol, or benzylalcohol and altering the oxyalkylation 3equence as follows:
Step 1: R-OH + m CH -CH ~ R-O-~-EO )~H
Step 2: -t-mH + (2n + 1) CH2-CH-CH
1273~41 R-O ( ~ ~ PO-3-2- IH
Step 3: R-O-~-EO ~ ~n+IH ~ m CH2-CH2 ___~
R-O ( EO ~ PO ~ EO )mH.
Such mono-capped block polyethers where the cap is joined to the block polyether by an ether linkage are hydrolytically ~table and have been ~hown to posses~ different physical and chemical properties as compared to their non-capped ana-logues including modified surface activity and increa~ed thermal stability.
The polyoxyalkylene polyethers described above have proven useful in numerous applications, particularly those requiring surface active properties such as deter-gent~, foaming and defoaming agentA, emulaifying and dispersing agents, and a~ thickeners in aqueous ~y tems.
However, despite their great utility, the method3 of preparation previously de~cribed never results in a single, uniform product molecule, but in a cogeneric mixture containing molecules with widely varying total molecular weights as well as widely varying hydrophobe and hydrophile weights. This is particularly true as the molecular weight~
~73~4'1 increase. Although it is well known that block polyether surfactants having uniform, narrow molecular weights and compo~itions possess properties markedly different fro0 ~hose of ordinary commercial products, it has been impos-sible to prepare such specialty products wi~hout inordinate expense.
It ha3 now been surprisingly discovered that polyoxyalkylene block polyetherq having narrow molecular weight distribution, uniform composition, and unexpectedly low levels of un~aturation may be simply and economically prepared through the use of cesium hydroxide catalysis for at least the oxyethylation portion of the polyether syn-thesi~, and preferably for both oxyethylation and oxypropyl-ation.
The use of cesium hydroxide as a polyoxypropyla-tion catalyst ha~ been proposed in U.S. Patent 3,393,243.
According to this reference, the use of cesium hydroxide as opposed to conventional ~odium or potassium hydroxide catalysts in the synthesis of polyoxypropylene glycols prevents the elimination reaction at the polyether chain terminu~, which ordinarily results in forming allylic unsaturation and, at the same time, lower~ and broadens the molecular weight of the product polyoxypropylene glycols.
A mechanism for the elimination disclo~ed in U.S.
Patent 3,393,243 is discu~sed in Ceresa, Block and Graft 12731~
Copolymerization, vol. 2, published by Wiley-Interscience at page 18. The mechan$sm apparently involve~ hydrogen abstration via a specific cyclic tran3ition state which may be repre~ented as follows:
~0 /\
R-O--~--polyoxyalkylene--~--OCH2-CH lH2 H2 ~ / CH-CH3 o~
R-0 ( polyoxyalkylene--~--OCH2-CH=CH2 + ~3~0 \
f H-CH3 The unsaturation formed increa~es a~ a direct function of equivalent weight. Eventually a point is reached wherein further propylene oxide addition fail~ to increa~e the molecular weight.
When oxyethylation rather than oxypropylation i~
performed, as in the preparation of block polyethers, the use of cesium hydroxide a~ a catalyst ha~ not been contem-plated. The reason for this i~ that while it i~ readily conceived that polyoxypropylene glycols may react by the above mechanism, the ~ame cannot be true for polyoxyethylene glycol~ or for oxyethylated polyoxypropylene glycols containing more than one oxyethyl group. Thus, until now, such block polyether~ have been prepared with le~ expen~ive sodium and pota3~ium hydroxide catalyst3.
For examplè, when a ~ingle oxyethyl group i8 added to a polyoxypropylene glycol, the elimination mechani~m may be written thusly:
~0\
R-0 (--polyoxyalkylene-~-OCH2-CH ICH2 H2C~ ~CH2 o~
R-O ~ polyoxyalkylene ~ OCH2-CH=CH2 + ~ 0\
However, when more than one oxyethyl group i~ present, the requisite transition ~tate cannot be achieved, and thus it had not been thought that the elimination products could affect in the polymerization reaction:
R-O-~-polyoxypropylene~ polyoxyethylene)~CH2-CH2 CH2-->no elimination ~0, ~273~41 Consequently, no elimination, no unsaturation formation, and therefore no lowering of the polyether molecular weight is expected during ethylene oxide addition, and, in fac~, none has been detected heretofore.
Summary of the Invention It has now been surpri~ingly discovered, contrary to previou~ belief, that unsaturation is produced not only during the preparation of polyoxypropylene glycol~ during oxypropylation of a suitable initiator, but is also formed during oxyethylation as well. There is at present no accepted mechani4m which to attribute this formation of unsaturation during ethylene oxide addition. It ha3 further been discovered that cesium hydroxide is effective in lowering the amount of unsaturation formed during ethylene oxide addition and, at the same time, producing block polyethers with narrow molecular weight di~tribution and uniform compoqition.
Description of ths Preferred Embodiments The polyoxyalkylene block polyethers of the qubject invention are prepared in the conventional manner, except that cesium hydroxide is utilized as the oxyalkyla-tion cataly~t rather than the conventional potassium hydroxide or qodium hydroxide catalyqts. Other, ~trongly 12~314~
ba~ic cesium salts, for example cesium methoxide, may also be util;zed. Preferably the catalyst contains, in addition to cesium hydroxide, n~ more than 50 mole percent of other alkali metal hydroxides and more pref~errably, no more than 20 mole percent. Most preferably, pure or technical grade cesium hydroxide alone is utilized.
When the polyoxypropylene or higher alkylene oxide-derived hydrophobe i5 prepared first by oxyalkyklating a mono-, di-, or higher functional initiator such as methanol, butanol, ethylene glycol, propylene glycol, butylene glycol, glycerine, tetrakis (2-hydroxypropyl)-ethylenediamine or the like, potassium hydroxide may be used as the initial oxyalkylation cataly t provided that the hydrophobe is of modest molecular weight, i.e., equivalent weights of less than 2000, preferably less than 1500.
However, in this case, the residual potassium hydroxide catalyst ~8 preferably removed prior to additional oxypropy-lation to higher molecular weights, and, in any case, before oxyethylation. The mechanics of polyether preparation are otherwise conventional and well known to tho~e skilled in the art. Examples of such preparation may be found, for example, in the treati~e by Schick entitled Nonionic Surfac-tants, and in U.S. Patents 2,674,619, 2,677,700, and
3,036, lsa ~
~27314~
~ he amount of cesium hydroxide ca~alyct utilized i9 the same as that utilized when sodium hydroxide or potassium hydroxide is the catalyst, on a mole-to-mole basis. Generally, from 0.005 percent to about 5 per~ent, preferably 0.005 percent to 2.0 percent, and most preferably 0.005 percent to 0.5 percent by weight of cataly3t relative to the finished product is utilized. The cataly~t composi-tion during oxyethylation should be e~sentially cesium hydroxide. Up to 50 mole percent of potassium or sodium hydroxide may be tolerated in the cesium hydroxide catalyst, but generally less than 20 mole percent, and preferably less than 10 mole percent relative to total catalyst are pre-ferred. Cesium alkoxide~ of Cl-C8 lower alkanols, particu-larly cesium methoxide, as well a~ other highly basic cesium salts may also be used if desired.
The hydrophobe of the polyoxyalkylene block polyether~ of the subject invention are derived from a higher alkylene oxide, or from tetrahydrofuran. By the term "higher alkylene oxide" is meant alkylene oxides having from 3 to about 18 carbon atoms in the alkylene moiety. While the hydrophobe is preferably a polyoxypropylene hydrophobe, other hydrophobes based on higher alkylene oxides such as 1,2-butylene oxide and 2,3-butylene oxide may also be used. Although not preferred, the hydrophobe also may be derived from C8 to C18 olefin oxides, or from the polymeri-i27314~L
zation of t~trahydrofuran. '.!~ oxyalkylation of a suitable initiator with a higher al~y~ .e oxide result~ in the synthesis of a polyoxy(higher alkylene) block.
The examples which follow serve to illu~trate the proces3 of the subject invention. All polyethers are prepared by conventional techniques with the exception of the particular catalyst utilized. The oxyalkylation is performed in a stainle~s 3teel high pressure 3tirred autoclave. The initial charge, consisting of initiator or intermediate base, and catalyst i9 vacuum stripped at a temperature of from about 90C to 125C and a pre3sure of c.a. 10 torr to remove water. The propylene oxide feed rates are adjusted 90 as to maintain the reactor pressure at 90 p~ig or below, including a 45 psig nitrogen pad~
12~3141 Comparative Example A
Unsaturation Formation Durin~ h~lene Oxide Addition A block polyether is prepared conventionally as described above. The initiator i~ tetrakis[2-hydroxy-propyl]ethylenediamine which i9 oxypropylated at a tempera-ture of 100C using conventional KOH catalysis at a cataly~t concentration of 0.08 percent by weight relative to the final product (post oxyethylation) weight. Following oxypropylation, a portion of the oxypropylated intermediate ba~e i8 treated with magne~ium silicate to remove residual KOH catalyst and analyzed. The c.a. 3900 Dalton molecular weight product has an unsaturation, expressed as mg. of RO
per gram of polyether, of 0.008. The remainder of the intermediate base is reacted at a temperature of 160C with sufficient ethylene oxide to produce a polyoxypropylene-polyoxyethylene tetrol having a nominal molecular weight, based on ethylene oxide charged, of 39,500 Daltons. This product is treated with magnesium ~ilicate to remove residual KOH catalyst and analyzed. The product has a measured unsaturation of 0.054 meq KOH/g. A 15 percent by weight aqueous solution has a viscoqity at 50C of only 18.0 centistokes.
This example illustrates that unsaturation i~
formed during ethylene oxide addition as well as during propylene oxide addition, a phenomenon not previou~ly 1273~43~
considered of importance in block copolymer synthesis. It was expected that un~aturation produced during oxypropyla-tion would be "diluted" during ethylene oxide addition. The finished product, which has a molecular weight approximately ten times higher than the polyoxypropylene polyether intermediate base, would therefore have an unsaturation one-tenth as great, or approximately 0.0008 meq KOH/g. However, instead of thi~ very low, almost insignificant level of unsaturation, the finished product ~hows an unsaturation o~
0.054 meq KOH/g, some seven times higher than the interme-diate ba~e, and sixty-seven times higher than expected! The elimination mechanism discussed previously cannot account for the large increase in unsaturation.
The molecular weight distribution of the polyether of Comparative Example A as shown by gel permeation chroma-tography is qhown in Figure 1 as "polyether A. n As indi-cated, the molecular weight distribution is rather broad, with the major peak centered at a molecular weight of only 36,000 Daltons, considerably below the theoretical molecular weight of 39,500 Dalton~. In addition, a large ~houlder, representing about 15 percent by we~ght of the polyether, has a molecular weight of only 9700 Daltons.
~7~4~
Example 1 The proce3s of Comparative Example A is followed except that a 1:1 mixture of cesium hydrcxide and pota~sium hydroxide i9 used throughout the oxyalkylation with both propylene oxide and ethylene oxide. The ethylene oxide addition temperature i9 135C. The hydrophobe ha~ a nominal molecular weight of 3900 Daltons, while the product poly-ether molecular weight i~ 39,500 Daltons as in Example A.
The product has an aqueous viscosity at 15 percent concen-tration of 177 centistokes at 50C. The unsaturation, determined graphically by interpolation from known values, i8 .005 meq KOH/g. The molecular weight distribution, as determined by gel permeation chromatography, is shown in Figure 1 as "polyether 1. n The bulk of the product elutes as a narrow peak centered at 42,000 Daltonq. This is a considerably narrower range than that achieved through conventional catalysis as indicated by the chromatograph of Comparative Example A. In addition, the cesium hydroxide catalyzed product has a higher overall molecular weight.
Example 2 The process of Example 1 is followed, but cesium hydroxide alone i3 used for the oxyalkylation. The product gels at 15 percent aqueous concentration. A 12 percent by weight aqueou~ solution has a viscosity of 57.9 centi-stokes. The unsaturation is estimated graphically to be ~73~4~L
0.004 meq KOH/g. The molecular weigh. distribution i9 ~hown in figure 1. A fairly narrow peak at 40,000 Daltons compri~es the bulk of the polyether, with only a clight shoulder at 12,000 Daltons, indicating that ~he ceæium hydroxide catalyzed product ha~ both higher overall molecular weight and a narrower molecular weiqht di~tribu-tion than conventionally catalyzed product~.
Example 3 The proce~s of Example 1 i~ followed, but oxy-propylation i~ Atopped after 20 mole~ of propylene oxide are added. Following removal of residual KOH cataly~t by means of magneRium Ailicate, the c.a. 1700 mw polyoxypropylated product i9 recatalyzed with an amount of ce~ium hydroxide chemically equivalent to the amount of KOH originally u~ed. Sufficient additional propylene oxide iq added to achieve a nominal hydrophobe molecular weight of 3900 Daltons, following which ethylene oxide iR added to achieve a final polyether molecular weight of 39,500 Daltons, as before. The 50C aqueou~ vi~cosity at 15 percent by weight concentration i~ 109 centistoke~. The product ha~ an e~timated unsaturation of 0.006 meq KOH/g determined graphically from the aqueou~ meaAured viRcosity.
~Z7314~L
Comparison Example B
A conventional triblock polyoxyalkylene polyether i9 prepared by oxypropylating propylene glycol in the presence of KOH as the cataly~t until a molecular weight of 3000 Dalton~ is obtained, following which ethylene oxide is added until the polyoxyethylene-polyoxypropylene-polyoxy-ethylene polyether has a nominal theoretical molecular weight of 10,000 Daltons calculated from the measured hydroxyl number of 8.9 meq KOH/g. A 20 percent by weight aqueous solution of the solid product produces a gel.
Example 4 A triblock polyoxyalkylene polyether i9 produced exactly as in Comparison Example B except that cesium hydroxide replaces potassium hydroxide as the catalyst on a mole-to-mole basis. The product has a hydroxyl number identical to tha~ of the polyether of Comparison Example B, but an aqueous gel is produced at only 16 percent solids, an improvement of 20 percent.
~27314~
~ he amount of cesium hydroxide ca~alyct utilized i9 the same as that utilized when sodium hydroxide or potassium hydroxide is the catalyst, on a mole-to-mole basis. Generally, from 0.005 percent to about 5 per~ent, preferably 0.005 percent to 2.0 percent, and most preferably 0.005 percent to 0.5 percent by weight of cataly3t relative to the finished product is utilized. The cataly~t composi-tion during oxyethylation should be e~sentially cesium hydroxide. Up to 50 mole percent of potassium or sodium hydroxide may be tolerated in the cesium hydroxide catalyst, but generally less than 20 mole percent, and preferably less than 10 mole percent relative to total catalyst are pre-ferred. Cesium alkoxide~ of Cl-C8 lower alkanols, particu-larly cesium methoxide, as well a~ other highly basic cesium salts may also be used if desired.
The hydrophobe of the polyoxyalkylene block polyether~ of the subject invention are derived from a higher alkylene oxide, or from tetrahydrofuran. By the term "higher alkylene oxide" is meant alkylene oxides having from 3 to about 18 carbon atoms in the alkylene moiety. While the hydrophobe is preferably a polyoxypropylene hydrophobe, other hydrophobes based on higher alkylene oxides such as 1,2-butylene oxide and 2,3-butylene oxide may also be used. Although not preferred, the hydrophobe also may be derived from C8 to C18 olefin oxides, or from the polymeri-i27314~L
zation of t~trahydrofuran. '.!~ oxyalkylation of a suitable initiator with a higher al~y~ .e oxide result~ in the synthesis of a polyoxy(higher alkylene) block.
The examples which follow serve to illu~trate the proces3 of the subject invention. All polyethers are prepared by conventional techniques with the exception of the particular catalyst utilized. The oxyalkylation is performed in a stainle~s 3teel high pressure 3tirred autoclave. The initial charge, consisting of initiator or intermediate base, and catalyst i9 vacuum stripped at a temperature of from about 90C to 125C and a pre3sure of c.a. 10 torr to remove water. The propylene oxide feed rates are adjusted 90 as to maintain the reactor pressure at 90 p~ig or below, including a 45 psig nitrogen pad~
12~3141 Comparative Example A
Unsaturation Formation Durin~ h~lene Oxide Addition A block polyether is prepared conventionally as described above. The initiator i~ tetrakis[2-hydroxy-propyl]ethylenediamine which i9 oxypropylated at a tempera-ture of 100C using conventional KOH catalysis at a cataly~t concentration of 0.08 percent by weight relative to the final product (post oxyethylation) weight. Following oxypropylation, a portion of the oxypropylated intermediate ba~e i8 treated with magne~ium silicate to remove residual KOH catalyst and analyzed. The c.a. 3900 Dalton molecular weight product has an unsaturation, expressed as mg. of RO
per gram of polyether, of 0.008. The remainder of the intermediate base is reacted at a temperature of 160C with sufficient ethylene oxide to produce a polyoxypropylene-polyoxyethylene tetrol having a nominal molecular weight, based on ethylene oxide charged, of 39,500 Daltons. This product is treated with magnesium ~ilicate to remove residual KOH catalyst and analyzed. The product has a measured unsaturation of 0.054 meq KOH/g. A 15 percent by weight aqueous solution has a viscoqity at 50C of only 18.0 centistokes.
This example illustrates that unsaturation i~
formed during ethylene oxide addition as well as during propylene oxide addition, a phenomenon not previou~ly 1273~43~
considered of importance in block copolymer synthesis. It was expected that un~aturation produced during oxypropyla-tion would be "diluted" during ethylene oxide addition. The finished product, which has a molecular weight approximately ten times higher than the polyoxypropylene polyether intermediate base, would therefore have an unsaturation one-tenth as great, or approximately 0.0008 meq KOH/g. However, instead of thi~ very low, almost insignificant level of unsaturation, the finished product ~hows an unsaturation o~
0.054 meq KOH/g, some seven times higher than the interme-diate ba~e, and sixty-seven times higher than expected! The elimination mechanism discussed previously cannot account for the large increase in unsaturation.
The molecular weight distribution of the polyether of Comparative Example A as shown by gel permeation chroma-tography is qhown in Figure 1 as "polyether A. n As indi-cated, the molecular weight distribution is rather broad, with the major peak centered at a molecular weight of only 36,000 Daltons, considerably below the theoretical molecular weight of 39,500 Dalton~. In addition, a large ~houlder, representing about 15 percent by we~ght of the polyether, has a molecular weight of only 9700 Daltons.
~7~4~
Example 1 The proce3s of Comparative Example A is followed except that a 1:1 mixture of cesium hydrcxide and pota~sium hydroxide i9 used throughout the oxyalkylation with both propylene oxide and ethylene oxide. The ethylene oxide addition temperature i9 135C. The hydrophobe ha~ a nominal molecular weight of 3900 Daltons, while the product poly-ether molecular weight i~ 39,500 Daltons as in Example A.
The product has an aqueous viscosity at 15 percent concen-tration of 177 centistokes at 50C. The unsaturation, determined graphically by interpolation from known values, i8 .005 meq KOH/g. The molecular weight distribution, as determined by gel permeation chromatography, is shown in Figure 1 as "polyether 1. n The bulk of the product elutes as a narrow peak centered at 42,000 Daltonq. This is a considerably narrower range than that achieved through conventional catalysis as indicated by the chromatograph of Comparative Example A. In addition, the cesium hydroxide catalyzed product has a higher overall molecular weight.
Example 2 The process of Example 1 is followed, but cesium hydroxide alone i3 used for the oxyalkylation. The product gels at 15 percent aqueous concentration. A 12 percent by weight aqueou~ solution has a viscosity of 57.9 centi-stokes. The unsaturation is estimated graphically to be ~73~4~L
0.004 meq KOH/g. The molecular weigh. distribution i9 ~hown in figure 1. A fairly narrow peak at 40,000 Daltons compri~es the bulk of the polyether, with only a clight shoulder at 12,000 Daltons, indicating that ~he ceæium hydroxide catalyzed product ha~ both higher overall molecular weight and a narrower molecular weiqht di~tribu-tion than conventionally catalyzed product~.
Example 3 The proce~s of Example 1 i~ followed, but oxy-propylation i~ Atopped after 20 mole~ of propylene oxide are added. Following removal of residual KOH cataly~t by means of magneRium Ailicate, the c.a. 1700 mw polyoxypropylated product i9 recatalyzed with an amount of ce~ium hydroxide chemically equivalent to the amount of KOH originally u~ed. Sufficient additional propylene oxide iq added to achieve a nominal hydrophobe molecular weight of 3900 Daltons, following which ethylene oxide iR added to achieve a final polyether molecular weight of 39,500 Daltons, as before. The 50C aqueou~ vi~cosity at 15 percent by weight concentration i~ 109 centistoke~. The product ha~ an e~timated unsaturation of 0.006 meq KOH/g determined graphically from the aqueou~ meaAured viRcosity.
~Z7314~L
Comparison Example B
A conventional triblock polyoxyalkylene polyether i9 prepared by oxypropylating propylene glycol in the presence of KOH as the cataly~t until a molecular weight of 3000 Dalton~ is obtained, following which ethylene oxide is added until the polyoxyethylene-polyoxypropylene-polyoxy-ethylene polyether has a nominal theoretical molecular weight of 10,000 Daltons calculated from the measured hydroxyl number of 8.9 meq KOH/g. A 20 percent by weight aqueous solution of the solid product produces a gel.
Example 4 A triblock polyoxyalkylene polyether i9 produced exactly as in Comparison Example B except that cesium hydroxide replaces potassium hydroxide as the catalyst on a mole-to-mole basis. The product has a hydroxyl number identical to tha~ of the polyether of Comparison Example B, but an aqueous gel is produced at only 16 percent solids, an improvement of 20 percent.
Claims (19)
1. A process for the preparation of polyoxyalky-lene block polyethers containing one or more polyoxyethylene moieties and one or more polyoxy(higher alkylene) moieties, comprising catalyzing at least the formation of said polyoxyethylene moiety from ethylene oxide with a basic cesium-containing catalyst.
2. The process of claim 1 wherein said basic cesium-containing catalyst comprises cesium hydroxide.
3. The process of claim 2 wherein said polyoxy-(higher alkylene) moiety is derived from oxyalkylation with an alkylene oxide selected from the group consisting of propylene oxide and butylene oxide.
4. The process of claim 2 wherein said polyoxy-(higher alkylene) moiety is derived from a cyclic ether from the group consisting of oxetane and tetrahydrofuran.
5. The process of claim 2 wherein said cesium hydroxide-containing catalyst comprises cesium hydroxide and potassium hydroxide in a molar ratio greater than 1:3.
6. The process of claim 3 wherein said cesium hydroxide-containing catalyst comprises cesium hydroxide and potassium hydroxide in a molar ratio greater than 1:3.
7. The process of claim 4 wherein said cesium hydroxide-containing catalyst comprises cesium hydroxide and potassium hydroxide in a molar ratio greater than 1:3.
8. The process of claim 2 wherein said cesium hydroxide-containing catalyst consists essentially of cesium hydroxide.
9. The process of claim 3 wherein said cesium hydroxide-containing catalyst consists essentially of cesium hydroxide.
10. The process of claim 4 wherein said cesium hydroxide-containing catalyst consists essentially of cesium hydroxide.
11. The process of claim 1 wherein said cesium-containing catalyst comprises a basic cesium compound selected from the group consisting of cesium oxide, cesium carbonate, cesium acetate, and the cesium alkoxides of C1-C8 lower alkanols.
12. The process of claim 11 wherein both ethylene oxide addition and higher alkylene oxide addition is catalyzed by said catalyst containing a basic cesium compound.
13. A process for the preparation of polyoxyalky-lene block polyethers containing one or more polyoxyethylene moieties and one or more polyoxy(higher alkylene) moieties by sequential oxyalkylation with ethylene oxide and one or more higher alkylene oxides, comprising catalyzing all oxyalkylations with a cesium hydroxide-containing catalyst.
14. The process of claim 13 wherein said polyoxy-(higher alkylene) moiety is derived from oxyalkylation with an alkylene oxide selected from the group consisting of propylene oxide and butylene oxide.
15. The process of claim 13 wherein said cesium hydroxide-containing catalyst comprises cesium hydroxide and potassium hydroxide in a molar ratio greater than 1:3.
16. The process of claim 14 wherein said cesium hydroxide-containing catalyst comprises cesium hydroxide and potassium hydroxide in a molar ratio greater than 1:3.
17. The process of claim 13 wherein said cesium hydroxide-containing catalyst consists essentially of cesium hydroxide.
18. The process of claim 3 wherein said cesium hydroxide-containing catalyst contains cesium hydroxide and sodium hydroxide in a molar ratio greater than 1:3.
19. The process of claim 13 wherein said cesium hydroxide-containing catalyst contains cesium hydroxide and sodium hydroxide in a molar ratio greater than 1:3.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US06/932,575 US4764567A (en) | 1986-11-20 | 1986-11-20 | Process for the preparation of polyoxyalkylene block polyethers having enhanced properties |
| US932,575 | 1986-11-20 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1273141A true CA1273141A (en) | 1990-08-21 |
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ID=25462526
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000552223A Expired - Lifetime CA1273141A (en) | 1986-11-20 | 1987-11-19 | Process for the preparation of polyoxyalkylene block polyethers having enhanced properties |
Country Status (3)
| Country | Link |
|---|---|
| US (1) | US4764567A (en) |
| EP (1) | EP0268922A3 (en) |
| CA (1) | CA1273141A (en) |
Families Citing this family (32)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CA1312399C (en) * | 1986-11-21 | 1993-01-05 | Jay Gregory Otten | Process for preparing capped polyoxyalkylene block polyethers |
| US5567859A (en) * | 1991-03-19 | 1996-10-22 | Cytrx Corporation | Polyoxypropylene/polyoxyethylene copolymers with improved biological activity |
| US5674911A (en) * | 1987-02-20 | 1997-10-07 | Cytrx Corporation | Antiinfective polyoxypropylene/polyoxyethylene copolymers and methods of use |
| US4904466A (en) * | 1987-03-31 | 1990-02-27 | Basf Corporation | Polymers which form gels at low concentrations in water |
| AR243911A1 (en) * | 1988-11-18 | 1993-09-30 | Dow Chemical Co | Process for the preparation of polyether polyols with reduced unsaturation |
| WO1990015835A1 (en) * | 1989-06-16 | 1990-12-27 | The Dow Chemical Company | Process for preparing elastomeric polyurethane or polyurethane-urea polymers, and polyurethanes so prepared |
| US5010117A (en) * | 1989-06-16 | 1991-04-23 | Dow Chemical Company | Flexible polyurethane foams prepared using low unsaturation polyether polyols |
| DE3920662A1 (en) * | 1989-06-23 | 1991-01-10 | Henkel Kgaa | USE OF ETHYLENE OXIDE / PROPYLENEOXIDE BLOCK COPOLYMERS IN HYDRAULICALLY FILLING MASSES AND THE MASSES THUS OBTAINED |
| USRE38558E1 (en) | 1991-03-19 | 2004-07-20 | Cytrx Corporation | Polyoxypropylene/polyoxyethylene copolymers with improved biological activity |
| JP2647556B2 (en) * | 1991-03-19 | 1997-08-27 | サイトアーレクス・コーポレーシヨン | Polyoxypropylene / polyoxyethylene copolymers with improved biological activity |
| US5867937A (en) * | 1993-03-24 | 1999-02-09 | Smithers-Oasis Company | Method for decreasing hydrophobicity of peat, bark and rockwool in soilless mixes used for plant growth, promoting easier, faster and more even watering of such mixes without plant injury and providing activity for future watering |
| GB9312256D0 (en) * | 1993-06-15 | 1993-07-28 | Ici Plc | Novel polyols |
| CA2111047C (en) * | 1993-12-09 | 2002-02-26 | Paul-Etienne Harvey | Copolymer composed of ethylene oxyde and of at least one substituted oxiranne with a crosslinkable function, process for preparing it, and its use in the making of ionic conductingmaterials |
| EP0677543B2 (en) * | 1994-04-12 | 2006-11-15 | Mitsui Chemicals, Inc. | Preparation of polyoxyalkylene polyols, polymer polyols and flexible polyurethane foams |
| EP1181937A3 (en) * | 1994-08-09 | 2004-02-04 | Cytrx Corporation | Novel vaccine adjuvant and vaccine |
| CN1190412A (en) * | 1995-07-10 | 1998-08-12 | 陶氏化学公司 | Polyols having reduced unsaturation and process for producing same |
| IT1277376B1 (en) * | 1995-07-28 | 1997-11-10 | Euron Spa | BLOCK COPOLYMERS THEIR PREPARATION AND THEIR USE AS LUBRICANTS |
| US5883180A (en) * | 1995-11-09 | 1999-03-16 | Finishes Unlimited, Inc. | Water borne paint composition |
| ATE168703T1 (en) | 1995-12-29 | 1998-08-15 | Basf Corp | LOW UNSATURATED POLYOXYALKYLENE POLYETHER POLYOLS |
| US6103850A (en) * | 1995-12-29 | 2000-08-15 | Basf Corporation | Sealants made using low unsaturation polyoxyalkylene polyether polyols |
| US6040413A (en) | 1996-07-10 | 2000-03-21 | Basf Corporation | Composition of polytetramethylene ether glycols and polyoxy alkylene polyether polyols having a low degree of unsaturation |
| US5998574A (en) * | 1996-07-10 | 1999-12-07 | Basf Corporation | Compositions of polytetramethylene ether glycols and polyoxy alkylene polyether polyols having a low degree of unsaturation |
| DE19709031A1 (en) | 1997-03-06 | 1998-09-10 | Basf Ag | Process for the preparation of double metal cyanide catalysts |
| US6146757A (en) * | 1998-06-29 | 2000-11-14 | Techmer Pm | Wettable polymer fibers, compositions for preparaing same and articles made therefrom |
| DE19840585A1 (en) | 1998-09-05 | 2000-03-09 | Basf Ag | Process for the preparation of polyetherols by ring-opening polymerization of alkylene oxides |
| DE19903274A1 (en) | 1999-01-28 | 2000-08-03 | Basf Ag | Process for the preparation of polyether polyols |
| US6613714B2 (en) | 1999-06-02 | 2003-09-02 | Basf Aktiengesellschaft | Multimetal cyanide compounds, their preparation and their use |
| US6800583B2 (en) | 1999-06-02 | 2004-10-05 | Basf Aktiengesellschaft | Suspension of multimetal cyanide compounds, their preparation and their use |
| US6593500B2 (en) | 2001-01-19 | 2003-07-15 | Rhodia, Inc. | Process for alkoxylation with a boron-containing catalyst |
| US7241813B2 (en) * | 2001-12-21 | 2007-07-10 | Isotis Orthobiologics, Inc. | End-capped polymers and compositions containing such compounds |
| US7205337B2 (en) * | 2001-12-21 | 2007-04-17 | Isotis Orthobiologics, Inc. | End-capped polymers and compositions containing such compounds |
| CN100526366C (en) * | 2006-12-11 | 2009-08-12 | 江苏钟山化工有限公司 | Polytetrafuran-base block polyether diol and its preparing method |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3393243A (en) * | 1964-09-24 | 1968-07-16 | Jefferson Chem Co Inc | Process of preparing polyoxypropylene polyether polyols |
-
1986
- 1986-11-20 US US06/932,575 patent/US4764567A/en not_active Expired - Lifetime
-
1987
- 1987-11-10 EP EP87116561A patent/EP0268922A3/en not_active Withdrawn
- 1987-11-19 CA CA000552223A patent/CA1273141A/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| EP0268922A2 (en) | 1988-06-01 |
| EP0268922A3 (en) | 1990-01-17 |
| US4764567A (en) | 1988-08-16 |
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