Patent GB-851600-A (GB)
Title: Method of preparing esters
IPC: B01J31/02
Filed: 1956-10-08
Abstract: Polyesters are prepared by reacting at elevated temperature in the liquid phase, a di-carboxylic acid or anhydride thereof with a polyhydric alcohol in the presence of a catalytic amount of at least one compound of the general formula: MX4 wherein M is titanium or zirconium and X represents a hydroxy, alkoxy, aryloxy, acyloxy, hydroxy alkoxy, hydroxy poly alkoxy or amino alkoxy group or a chlorine or bromine atom, at least one X being an organic radical as defined above having from 1-18 carbon atoms, and removing water of esterification from the reaction mixture substantially as rapidly as it is formed.  Numerous Ti and Zr esters, acylates and chelates are specified as catalysts; typical compounds additional to those used in the examples are tetra-methyl and tetra-octadecyl titanates; hydroxy titanium-acetate, -hexanoate and -castor oil acylate; isopropoxy titanium octanoate and isopropoxy titanium tall oil acylate; tetra polyethylene glycol titanate, tetra triethanolamine titanate and its N-oleate; the corresponding zirconium compounds and certain zirconium and titanium mono halo trialkyl and dihalo dialkyl esters.  The catalyst may be used in amounts of 0,01-10% or more by weight of the acid.  Reduced or elevated pressures may be used. In Examples: (1) a mixture of adipic and lauric acids and butane diol -1:3 is refluxed in the presence of tetra isopropyl titanate while passing N2 therethrough and then the product is stripped in vacuo; (2) a mixture of phthalic anhydride, pelargonic acid, butane diol-1:3 and a small amount of n-butanol is reacted using the same catalyst, water being removed azeotropically, (3) a mixture of adipic acid palmitic acid and butane diol -1:3 is reacted as in (1); ethylene glycol and terephthalic acid may be similarly reacted yielding a high melting polyester.  Numerous other aliphatic, cyclo aliphatic and aromatic polycarboxylic acids and anhydrides and aliphatic and aromatic polyhydric alcohols are mentioned.  The polyesters produced may be hydroxy or carboxyl-terminated or substantially neutral esters, and be liquid or solid.  The hydroxy terminated esters may be reacted with isocyanates and the carboxyl terminated esters may be further reacted with polyhydric alcohols.  The solid polyesters may be used as water-proofing material on paper, cloth or metal.  Acid sensitive plastics e.g. polyvinyl chloride, may be plasticised by means of ester obtained by the above method from polyhydric alcohols and any carboxylic acid or anhydride thereof in the presence of the specified Ti catalysts (see Group IV(b)) p  and the catalyst may be retained in the ester whereby the plasticized resin is stabilised.  Specification 733,224 is referred to.  Reference has been directed by the Comptroller to Specification 792,236.ALSO:Esters are prepared by reacting at an elevated temperature in the liquid phase, a carboxylic acid or anhydride thereof with a polyhydric alcohol in the presence of a catalytic amount of one or more compounds of the general formula MX4 wherein M is titanium or zirconium and X represents a hydroxyl, alkoxy, aryloxy, acyloxy, hydroxy alkoxyl, hydroxy poly alkoxy or amino alkoxy group or a chlorine or bromine atom, at least one X being an organic radical specified above having 1 to 18 carbon atoms, and removing water of esterification from the reaction mixture substantially as rapidly as it is formed.  The catalysts are Ti and Zr esters, acylates and chelates and typical of many specified are tetramethyl, -phenyl and -octa decyl titanates; hydroxy titanium-acetate, -hexanoate, -oleate and-castor oil acylate; iso propoxy-titanium octanoate; tetra ethylene glycol titanate, tetra poly-ethylene glycol titanate, di butoxy di(ethylene glycol) titanate and tetra triethanolamine titanate; the corresponding zirconium compounds; and certain titanium and zirconium monohalo trialkyl and dihalo dialkyl esters.  The catalysts are generally used in amounts of 0,01-10% by weight of the acid.  The water of esterification may be removed by azeotropic distillation. Reduced or elevated pressures may be used.  Specified polyhydric alcohols include ethylene glycol, penta methylene glycol, glycerol, penta erythritol, penta cosane-1:25-diol, phenylene-1:3:5-triethyl alcohol and phenylene1:4-dioctyl alcohol.  Specified acids (or anhydrides) include saturated and unsaturated aliphatic mono-, di- and poly-carboxylic acids substituted sometimes by chlorine, bromine, CN, hydroxy or phenyl substituents, saturated and unsaturated cycloaliphatic mono-, di- and poly-carboxylic acids and aromatic mono-, di-and poly-carboxylic acids substituted sometimes by chlorine, bromine, hydroxy, nitro, methoxy or alkyl substituents. The specific Examples relate to the preparation of resinous poly-esters (see Group IV(a)).  The esters are useful as plasticisers.  The titanium ester catalysts may be prepared by reacting a titanium halide with an appropriate alcohol or phenol in the presence of an amine, e.g. pyridine.  If desired mixed esters may be obtained by use of a mixture of alcohols or by reacting the titanium halide stepwise with two different alcohols. Specification 733,244 is referred to.  Reference has been directed by the Comptroller to Specification 792,236.