Organic compounds -- part of the class 532-570 series – Organic compounds – Oxygen containing
Reexamination Certificate
2000-07-07
2002-03-12
Padmanabhan, Sreeni (Department: 1621)
Organic compounds -- part of the class 532-570 series
Organic compounds
Oxygen containing
C568S618000
Reexamination Certificate
active
06355845
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates to processes for preparing poly(oxyalkylene) polymers and to methods for preparing same.
Polyethers made from alkylene oxides are well known and useful in a number of applications such as detergent and cleaner compositions, oil well drilling fluids, inks, metal working fluids, lubricants in paper coating compositions, ceramics manufacturing, chemical intermediates for nonionic surfactants which in turn are used in cosmetics, textiles and chemical processing, polyurethanes which are used as flexible foams and elastomers, chemical intermediates for esters which are used in textile spin finishes, cosmetic agents, and as foam control agents for a wide variety of processes. These polymers may have no more than one oxyalkylene group in succession, or be a higher molecular weight polymer containing one or more long chains of consecutive oxyalkylene groups.
Polyethers of this type are commonly made through an anionic polymerization process, whereby the alkylene oxide is combined with an initiator compound and a strongly basic catalyst such as potassium hydroxide or certain organic amines. The initiator compound contains one or more oxyalkylatable groups such as hydroxyl, thiol, carboxylic acid and the like. The initiator compound determines the functionality (i.e., number of hydroxyl groups/molecule of product) and in some cases may introduce some desired functional group into the product.
There are some disadvantages of polymerizing alkylene oxides using these strongly basic catalysts. One problem is that the strongly basic catalysts do not produce a low polydispersity product when a tertiary alcohol initiator compound is used. In addition, the basic catalyst usually must be removed from the product before it is used, which increases manufacturing costs.
In addition, some kinds of initiator compounds cannot be alkoxylated using strongly basic catalysts, because they contain base-sensitive functional groups. For example, initiators containing certain types of alkenyl or alkynyl groups undergo a side reaction in which the alkenyl or alkynyl group will “migrate” along the molecular chain, so that the unsaturation in the polyether is at a different place than it was on the initiator. This is of particular concern when terminal unsaturation is desired. Often, unsaturation that is in a terminal position on the initiator migrates to a non-terminal position during the alkoxylation reaction.
Unsaturated compounds in which a triple bond is adjacent to a hydroxyl-substituted carbon atom are prone to decomposing during the alkoxylation reaction. Many compounds of this type are reaction products of acetylene with a ketone such as acetone or an aldehyde such as acetaldehyde. Alkali metal or alkaline earth bases can cause these initiators to decompose to regenerate acetylene. Acetylene is an explosion hazard.
In order to try to avoid these problems, Lewis acids such as boron trifluoride-diethyl etherate and organic amines such as triethylamine have been tried. However, some of these catalysts tend to promote the formation of large amounts of by-products, especially when it is attempted to add three or more moles of alkylene oxide per equivalent of initiator compound. The Lewis acid catalysts tend to catalyze “back-biting” reactions where the growing polymer chain reacts with itself. The reactions form cyclic ethers such as dioxane, dimethyldioxane and various crown ethers. These cannot be removed easily from the desired product, and so the product cannot be used in many applications.
Thus, it would be desirable to provide a method whereby polyethers made using certain unsaturated initiator compounds could be produced in good yield with low levels of by-products.
SUMMARY OF THE INVENTION
In one aspect, this invention is a process for preparing a polyether, comprising forming a mixture of an initiator compound having one or more oxyalkylatable groups, at least one alkylene oxide and a metal cyanide catalyst complex, and subjecting the mixture to conditions sufficient to activate the catalyst complex and to alkoxylate the oxyalkylatable groups of the initiator, wherein the initiator compound contains nonconjugated carbon-carbon unsaturation that is (a) migratable, as defined below, (b) adjacent to a hydroxyl-substituted tertiary carbon atom, or both (a) and (b).
In a second aspect, this invention is a poly(alkylene oxide) polymer containing the residue of an initiator compound having nonconjugated carbon-carbon unsaturation that is (a) migratable, as defined below, (b) adjacent to a hydroxyl-substituted tertiary carbon atom, or both (a) and (b), the polymer having an average alkoxy degree of polymerization of at least three moles of alkylene oxide per equivalent of initiator compound.
This invention permits the ready formation of polymers of unsaturated initiators containing certain types of carbon-carbon unsaturation that tend to engage in side-reactions during previous alkoxylation processes. The product polymers contain desired, predetermined types of carbon-carbon unsaturation that are predictable from the selection of the initiator compound.
DETAILED DESCRIPTION OF THE INVENTION
In this invention, certain initiator compounds are alkoxylated by reaction with one or more alkylene oxides in the presence of a catalytically effective amount of a metal cyanide catalyst. The alkoxylation is conducted by combining the initiator, metal cyanide catalyst and alkylene oxide. The catalyst is then allowed to become activated in the presence of the alkylene oxide. Once the catalyst has become activated, the mixture is subjected to conditions sufficient to polymerize the alkylene oxide. In this manner, the initiator compound becomes alkoxylated until poly(oxyalkylene) chains of a desired length are introduced. As discussed below, once polymerization has begun, other types of monomers that are copolymerizable with alkylene oxides can be polymerized as well.
The initiator compound used in the process contains carbon-carbon unsaturation, i.e., a carbon-carbon double bond (i.e., an alkenyl group) and/or a carbon-carbon triple bond (i.e., an alkynyl group). The carbon-carbon unsaturation is not conjugated, i.e., is not part of a sequence of two or more double or triple bonds that alternate with single bonds. Thus, the carbon-carbon unsaturation is not part of an aliphatic hydrocarbyl conjugated structure (such as —CH═CH—(CH═CH—)
x
), part of an aromatic group, nor part of a conjugated structure including carbonyl groups (such as a —CR═CR—C(O)— grouping, as is present, for example, in acrylic or methacrylic compounds, maleic acid, fumaric acid, and the like). In the forgoing structure, each R independently represents hydrogen or an unsubstituted or inertly substituted group hydrocarbon that is attached to the indicated carbon atom through a carbon-carbon single bond. By “inertly substituted”, it is meant a group that does not react under the conditions of the alkoxylation process of the invention.
In addition, the carbon-carbon unsaturation is either migratable, adjacent to a hydroxyl-substituted tertiary carbon atom, an alkyne which is base sensitive or any combination of the above. In the case of a carbon-carbon double bond, “migratable” means that the unsaturation is adjacent to a —CHR
6
— group that is not substituted with any heteroatom, where R
6
is hydrogen or an unsubstituted or inertly substituted alkyl group. Thus, a migratable alkenyl group would have the structure —CR═CR—CHR
6
—R
1
OH, where R is as defined above and R
1
is an unsubstituted or inertly substituted alkylene group. A migratable alkynyl group is adjacent to a methylene group and would have the structure —C≡C—CH
2
—R
1
OH, where R
1
is as defined above. Unsaturation of this type can “migrate” to the adjacent —CHR
6
— or —CH
2
— group under basic conditions. Thus, for example, the migratable alkenyl group shown above can isomerize to form a —CHR—CR═CR
6
—R
1
OH group under basic conditions. In the same way, the migratable alkynyl group shown above can isomerize
Clement Katherine S.
Rauscher Wanda W.
Walker Louis L.
Wehmeyer Richard M.
Whitmarsh Robert H.
Padmanabhan Sreeni
The Dow Chemical Company
Witherspoon Sikarl A.
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