Patent GB-777215-A (GB)
Title: Improvements in catalysts useful in the preparation of polyesters
IPC: C08G63/688
Filed: 1953-10-02
Abstract: Polyesters are made by condensing a dicarboxylic acid ester with a polyhydroxy compound (or ester thereof) in presence of a catalyst consisting of a compound of formula: M(Al(OR)4) where M is an alkali metal and R is an alkyl radical of from 1-6 carbon atoms.  Preferably there are condensed under substantially anhydrous conditions (1) an aromatic dicarboxylic acid ester of formula: R1OOC-R2-X-R3-COOR4 wherein R1 and R4 each represent an alkyl radical containing 1-10 carbon atoms or an o -hydroxyalkyl radical containing 2-12 carbon atoms, R2 and R3 each represent (CH2)n-1, where n is 1-5 and X represents a divalent aromatic radical having one of the following formulm 9: <FORM:0777215/IV(a)/1> and <FORM:0777215/IV(a)/2> wherein Y represents a divalent radical which is: <FORM:0777215/IV(a)/3> and <FORM:0777215/IV(a)/4> where m is 1-5, and (2) a dihydroxy compound or an ester thereof of formula: R5O-(CH2)p-OR6 or R5O-(R7O)q-R7O-R6 where p is 2-12, R5 and R6 each represent a hydrogen atom or an acyl radical of 2-4 carbon atoms, R7 is an alkylene radical of 2-4 carbon atoms and q is 1-10; the reaction being performed (a) at an elevated temperature which is increased gradually during the course of the reaction to about 225 DEG -310 DEG  C, (b) in an inert atmosphere, and (c) at a very low pressure (preferably less than 15 mm. of Hg.) during the latter part of the reaction.  Many dehydroxy compounds and aromatic dicarboxylic acid esters falling within the above formulm 9 are referred to.  Condensation may be performed in presence of a solvent, e.g. diphenyl ether, diphenyl, mixed tolyl sulphones, chlorinated diphenyl, chlorinated naphthalene or dimethyl sulpholane. Part of the aromatic dicarboxylic ester may be replaced by an ester of an aliphatic dibasic acid, e.g. carbonic, oxalic, succinic, sebacic, a  : a -dimethylglutaric, dimethyl malonic, diglycollic, b -oxydipropionic, g -oxydibutyric, maleic, fumaric or itaconic acids. Other esters may be included, e.g. those of linoleic or linolenic acids or the fatty acids of linseed, soybean, cottonseed or tung oil. Part of the dihydroxy compound may be replaced by a polyhydroxy compound containing 3 or more hydroxy groups, e.g. glycerol, sorbitol, pentaerythritol, dipentaerythritol, b -methyl glycerol, 2-methyl - 2 - hydroxymethyl - 1 : 3 - propanediol or 1 : 2 : 4-trihydroxybutane.  When employing these polyhydroxy compounds and/or esters of unsaturated acids, the condensation is preferably terminated at about 250 DEG  C. and before pressure is reduced whereby soluble polyesters are produced suitable for use in coating compositions.  In examples polyesters are obtained by condensing (1) dimethyl terephthalate and ethylene glycol.  (2) The dibutyl ester of p : p1-sulphonyl dibenzoic acid and pentanediol.  (3) The dibutyl ester of p : p1-sulphonyl dibenzoic acid and 1 : 6-hexanediol.  (4) The diethyl ester of p : p1-sulphonyl dibenzoic acid and 1 : 5-pentanediol.  (5) Dimethyl sebacate, the dibutyl ester of p : p1-sulphonyl dibenzoic acid and 1 : 6-hexane diol.  (6) Dimethyl isophthalate, the diethyl ester of p : p1-sulphonyl dibenzoic acid and 1 : 5-pentane diol.  (7) Dimethyl terephthalate and ethylene glycol. (8) The diethyl ester of p : p1-sulphonyl dibenzoic acid, the diethyl ester of dimethyl malonic acid and pentamethylene glycol. (9) The diethyl ester of p : p1-sulphonyl dibenzoic acid, diethylene glycol and tetramethylene glycol.  (10) The dibutyl ester of p : p1-sulphonyl dibenzoic acid, dimethyl orthophthalate and pentamethylene glycol.  (11) The dibutyl ester of p : p1-sulphonyl dibenzoic acid, dimethyl ortho phthalate and tetramethylene glycol. (12) Diethyl oxalate and pentamethylene glycol to form a low molecular weight polymer followed by the addition of the diethyl ester of p : p1-sulphonyl dibenzoic acid and pentamethylene glycol and further condensation.  (13) The diethyl ester of p : p1-sulphonyl dibenzoic acid, diethylsuccinate and pentanediol-1 : 5.  (14) The diethyl ester of p : p1-sulphonyl dibenzoic acid, diglycollic acid diethyl ester and pentamethylene glycol.  (15) The dibutyl ester of p : p1-sulphonyl dibenzoic acid and ethylene glycol.  (16) p : p1-Dicarbethoxydiphenyl methane and ethylene glycol.  (17) p : p-Dicarbomethoxybenzophenone and trimethylene glycol.  (18) 1 : 2-Bis-(p-carbopropoxyphenyloxy) ethane and ethylene glycol. Some of the polyesters of the examples are useful for making fibres, films, sheets or photographic film bases, for injection moulding, for electrical insulation or for extruding into tubes or rods. Specifications 744,975, 777,217, 777,218, 777,219 and 777,220 are referred to.