Organic compounds -- part of the class 532-570 series – Organic compounds – Carboxylic acid esters
Patent
1997-03-07
1998-06-30
Geist, Gary
Organic compounds -- part of the class 532-570 series
Organic compounds
Carboxylic acid esters
560103, 568606, 568617, C07C 6724, C07C 4318
Patent
active
057736480
DESCRIPTION:
BRIEF SUMMARY
This is a national stage application of PCT international application PCT/EP 95/03651 filed Sep. 21, 1995, published as WO96/09335 Mar. 28, 1996.
The present invention relates to a process for the preparation of polytetrahydrofuran or polytetrahydrofuran monoesters of C.sub.1 -C.sub.10 monocarboxylic acids by the polymerization of tetrahydrofuran over a heterogeneous catalyst in the presence of one of the telogens water, 1,4-butanediol or polytetrahydrofuran having a molecular weight of from 200 to 700 dalton, of a C.sub.1 -C.sub.20 monocarboxylic acid or of a carboxylic anhydride derived from C.sub.2 -C.sub.20 monocarboxylic acids, or mixtures of these telogens.
Polytetrahydrofuran (PTHF), also called poly(oxybutylene glycol), serves as intermediate for the preparation of polyurethane, polyester and polyamide elastomers, for the preparation of which it is employed as diol component. The inclusion of PTHF in these polymers causes the latter to become soft and flexible, for which reason PTHF is also referred to as a soft segment component for these polymers. Polytetrahydrofuran monoesters of monocarboxylic acids are used, for example, as plasticizers (U.S. Pat. No. 4,482,411), impregnating agents (DE-A 2,932,216), monomers (EP-A 286,454), emulsifiers, and dispersing aids (JP-A 138452/1987) and are further employed for de-inking in the regeneration of waste paper (JP-A 303190/1988).
The cationic polymerization of tetrahydrofuran (THF) with the aid of catalysts has been described by Meerwein et al (Angew. Chem. 72, 927 (1960)). Either preformed catalysts are used as catalysts during this process, or the catalysts are produced in situ in the reaction mixture. This takes place by producing oxonium ions in the reaction medium with the aid of strong Lewis acids such as boron trichloride, aluminum chloride, tin tetrachloride, antimony pentachloride iron(III) chloride, or phosphorus pentafluoride or by means of strong Broensted acids, such as perchloric acid, tetrafluoroboric acid, fluorosulfonic acid, chlorosulfonic acid, hexachlorostannic acid, iodic acid, hexachloroantimonic acid, or tetrachloroferric acid and with the aid of reactive compounds designated as promotors, such as alkylene oxides, eg, ethylene oxide, propylene oxide, epichlorohydrin, or butylene oxide, oxetanes, orthoesters, acetals, .alpha.-halo ethers, benzyl halides, triarylmethyl halides, acid chlorides, .beta.-lactones, carboxylic anhydrides, thionyl chloride, phosphorus oxychloride, or sulfonic halides, which oxonium ions initiate the polymerization of the THF. Of the large number of these catalyst systems few only have attained commercial significance however, since they are in some cases highly corrosive and/or in the preparation of PTHF lead to discolored PTHF products having only restricted usefulness.
Moreover many of these catalyst systems do not operate in a truly catalytical manner, but must be employed in stoichiometric amounts, based on the macromolecule to be prepared, and are consumed during the polymerization. For example, in the preparation of PTHF using fluorosulfonic acid as catalyst according to U.S. Pat. No. 3,358,042, two molecules of fluorosulfonic acid must be used as catalyst per molecule of PTHF. A particular drawback of the use of halogen-containing catalysts is that these lead to the formation of halogenated by-products during the preparation of PTHF, which are very difficult to separate from pure PTHF and have a detrimental influence on its properties.
In the preparation of PTHF in the presence of the promoters cited these promoters are incorporated as telogens in the PTHF molecule so that the primary product of the THF polymerisation is not PTHF but a PTHF derivative, for example, a PTHF diester or sulfonate, from which the PTHF must be freed in a further reaction, eg, by saponification or transesterification (of U.S. Pat. No. 2,499,725 and DE-A 2,760,272). When using alkylene oxides as promoters these also act as comonomers and are incorporated in the polymer with the result that THF alkylene oxide copolymers are fo
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Becker Rainer
Eller Karsten
Fischer Rolf
Heilen Gerd
Hesse Michael
BASF - Aktiengesellschaft
Geist Gary
Keys Rosalynd
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