Claims
- 1. A process for preparing a polyester from hydroxyalkyl dicarboxylic acid ester monomer and/or oligomers comprising:
- a) introducing reaction materials having a DP of 1-40 of hydroxyalkyl dicarboxylic acid ester monomers and/or oligomers into a pipe or tubular reactor, wherein said monomer and/or oligomers have a mole ratio of glycol equivalents to carboxylic acid equivalents of from 1.0:1 to 1.2:1 considering all points of addition;
- b) introducing a dense gaseous medium into said reactor, said dense gaseous medium being an ether, a ketone or a mixture thereof;
- c) operating said reactor at superatmospheric pressure and at sufficient temperature to:
- 1) achieve a turbannular flow regime comprising said reaction materials and said gaseous medium before leaving the reactor;
- 2) cause polyesterification to occur whereby the reaction material polymerizes to produce a polyester, with the DP of the reaction material polymer increasing from the beginning of the reactor to the end; and
- 3) produce water with little or no other reaction by-products or little or no unreacted monomers or oligomers which are separated from the polymer product through the gaseous medium phase.
- 2. The process of claim 1, wherein said dense gaseous medium is a dimethyl ether.
RELATED U.S. APPLICATIONS
This is a continuation application of U.S. application Ser. No. 09/185,998 allowed which was filed on Nov. 4, 1998.
US Referenced Citations (2)
Foreign Referenced Citations (2)
Number |
Date |
Country |
WO9622318 |
Jul 1996 |
WOX |
WO9639456 |
Dec 1996 |
WOX |
Continuations (1)
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Number |
Date |
Country |
Parent |
185998 |
Nov 1998 |
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