Patent GB-678264-A (GB)
Title: Improvements in linear polyesters
Inventor: FISHER JAMES WOTHERSPOON
IPC: C08G63/672
Filed: 1948-04-28
Abstract: Linear polyesters are produced by condensing an aromatic dicarboxylic acid or ester-forming derivative thereof with a bis-b -oxyethyl derivative of a diphenol whose phenol groups are linked to each aromatic nucleus so that the linkages are separated by at least four carbon atoms in each nucleus or with an ester-forming derivative of such a glycol.  Aromatic nuclei mentioned are those of phenol, naphthalene, diphenyl, diphenyl alkane, diphenyl sulphone and those of the type <FORM:0678264/IV (a)/1> where R is -CO-, -O-, -S-, -SO2-, or -NR-. Glycols mentioned are bis-b -oxyethylhydroquinone; bis - b - oxyethyl-4,41-dihydroxy diphenyl; and the corresponding derivatives of 2,5-dichlorohydroquinone, 4,41 - dihydroxybenzophenone, 4,41 - dihydroxydiphenylsulphone, a ,b -bis-(4-hydroxyphenoxy) - ethane, 4,41 - dihydroxy - 3,5,31,51-or 2,5,21,51-tetramethyldiphenyl and of 1,4, 1,5, 2,6 and 2,7-dihydroxynaphthalenes.  Aromatic dicarboxylic acids mentioned are terephthalic acid, 4,41-dicarboxydiphenyl and 4,41-dicarboxy - a ,b  - diphenoxyethane.  Ester-forming derivatives of the glycols are formates or acetates and of the acids are the acid chlorides or methyl or ethyl esters. Condensation is preferably effected in liquid phase, e.g. with phenol or n-cresol as a solvent. Condensation temperatures may be between 100 DEG  and 350 DEG  C. Catalysts which facilitate elimination of water e.g. p-toluene sulphonic or phosphoric acid, or which absorb HCl, e.g. an inorganic alkali such as potassium carbonate or a tertiary organic base, such as pyridine or dimethylamine or a terpene, or ester-interchange catalysts, e.g. alkali metals or magnesium or alkali alcoholates may be present.  Low pressure aids removal of water.  Oxygen-free inert gas, e.g. hydrogen or nitrogen may be passed over or through the reaction mixture.  The reagents are preferably used in substantially equimolecular proportions.  In the example: p-bis - (b  - hydroxyethoxy) - benzene is condensed with dimethyl terephthalate in presence of a little ethylene glycol, magnesium ribbon and a solution of sodium in ethanol.  Hydrogen is bubbled through the mass.  The polymer melted at 197-198 DEG  C.  Samples have been furnished under Sect. 2 (5) of polymers produced from dimethyl terephthalate and (1) 4,41-di-(b -hydroxyethoxy)-diphenyl; (2) 2,6-di-(b -hydroxyethoxy)-naphthalene, and (3) 1,5-di-(b -hydroxyethoxy)-naphthalene.ALSO:Bis-b -(hydroxyethoxy) derivatives of diphenols are prepared by reaction between ethylene halogen hydrin and the diphenol as the alkali metal salt or in alkaline solution. Diphenols mentioned are hydroquinone, 2,5-dichlorohydroquinone, 4,41 - dihydroxydiphenyl, 4,41 - dihydroxybenzophenone, 4,41-dihydroxydiphenylsulphone, a ,b  - bis - (4-hydroxyphenoxyethane), 4,41 - dihydroxy-3,5,31,51 or 2,5,21,51-tetramethyldiphenyl 1,4-or 1,5- or 2,6- or 2,7-dihydroxynaphthalene.  General reference is also made to bodies of the formula <FORM:0678264/IV (b)/1> in which R is a direct link, or (-CH2-)n, O, S or NR.  In the example, hydroquinone, ethylene, chlorhydrin, caustic potash and ethanol were refluxed together.  KCl was removed by filtration, and alcohol by evaporation.  Addition of water precipitated the product which was washed, decolourized with charcoal and recrystallized.  It melted at 104-105 DEG  C.  Samples filed make polyesters (Group IV (a)) from (1) 4,41 - di - (b  - hydroxyethoxy) - diphenyl (M.P. 210 DEG  C.); (2) 2.6-di-(b -hydroxy-ethoxy)-naphthalene (M.P. 189 DEG  C.) and (3) 1.5 - di - (b - hydroxyethoxy) - naphthalene (M.P. 179 DEG  C.).