Patent GB-849109-A (GB)
Title: Method of preparing esters
IPC: C08G63/85
Filed: 1956-10-08
Abstract: Polyesters are prepared by heating in the liquid phase a polyhydric alcohol and a polycarboxylic acid, an anhydride thereof or an ester thereof derived from an alcohol having a lower boiling point than that of the polyhydric alcohol, in the presence of a catalytic amount of a colloidal hydrated titanium dioxide.  The catalyst may be the gel obtained by hydrolysis of a titanium salt followed preferably by washing to remove salts ; the resulting gel may then be partially dehydrated.  Alternatively the colloidal catalyst may be that obtained by addition of a bivalent anionic radical to an aqueous solution of titanium dioxide or by mechanical peptization of a hydrated titanium dioxide.  The amount of catalyst may range from 0,01 to 10,0% or higher by weight of esterifiable acid compound.  In Examples : (8) a mixture of dibutyl adipate and butane diol 1 : 3 is refluxed using a titanium dioxide gel containing 30-40% TiO2, with continuous removal of liberated butanol yielding a viscous liquid polyester ; terephthalic acid and ethylene glycol may be reacted similarly ; (9) a mixture of adipic acid, butane diol -1 : 3 and lauric acid is similarly reacted in the presence of a hydrated gel containing 4-5% TiO2 with continuous removal of water and the product then further heated in vacuo.  Numerous other reagents are specified including saturated and unsaturated aliphatic, cyclo aliphatic and aromatic di- and higher polycarboxylic acids and anhydrides and esters thereof and saturated and unsaturated aliphatic and aromatic alcohols containing two or more hydroxyl groups.  Halogen containing polymers such as vinyl halide polymers are plasticised by esters obtained by heating an alcohol with a carboxylic acid, its anhydride or ester thereof with an alcohol having a lower boiling point than the alcohol to be esterified, the reaction being effected by heating in the presence of a catalytic amount of a colloidal hydrated titanium dioxide. Numerous esterifying reagents are specified (see Group IV(b)).ALSO:Esters are prepared by heating in the liquid phase an alcohol and a carboxylic acid, a carboxylic acid anhydride or an ester of an alcohol with a carboxylic acid, said ester being derived from an alcohol having a lower boiling point than that of the alcohol used in the reaction, in the presence of a catalytic amount of colloidal hydrated titanium dioxide.  The catalyst may be the gel obtained by hydrolysis of a titanium salt followed preferably by washing to remove inorganic salts; the resulting gel may be partially dehydrated.  The colloidal catalyst may also be that obtained by addition of a bivalent anionic radical to an aqueous solution containing titanium dioxide or by mechanical peptization of hydrated titanium dioxide.  The amount of catalyst may range from 0,01 to 10,0% or higher by weight of esterifiable acid compound.  In Examples: (1) di-(2-octyl) phthalate is prepared by refluxing a mixture of octanol-2 and phthalic anhydride in the presence of a hydrated titanium dioxide gel containing 5% TiO2, with continuous removal of water and the results are compared with the same esterifications effected with p-toluene sulphonic acid as catalyst and in the absence of a catalyst; (2)-(5) 2-ethyl hexanol is similarly esterified with phthalic anhydride, using hydrated titanium dioxide gels containing 4-5, 10 and 18% TiO2 and the results are compared with those from the same esterifications effected with titanium dioxide gels dehydrated to contain 76 and 100% TiO2. Numerous other ester forming reagents are specified.  Typical examples of carboxylic acids of the type R (COOH)n wherein R may be aliphatic, cyclo aliphatic or aromatic and n is an integer are hydro-, chloro-, bromo- and cyano-acetic acids, 5-phenyl valeric acid, a -hydroxy lignoceric acid, malonic acid, pentacosane-1 : 25-dicarboxylic acid, tricarballylic acid, stearic acid, acrylic acid, oleic acid, maleic acid, glutaconic acid, cyclohexane di-and hexa-carboxylic acids, cyclohexadiene-dicarboxylic acid, amino-, nitro- and methoxybenzoic acids, benzene tri- and tetra-carboxylic acids and terephthalic acid.  Additional anhydrides mentioned include adipic and itaconic acid anhydrides.  The alcohols are representable generally as R(OH)n where R is an organic radical and n an integer and these are typical: methanol, chloro-, cyano- and ethoxy-ethanols, nitro butanol, stearyl alcohol, 3-pentene-1-ol, ethylene glycol, 2 : 4-octa diene-1 : 8-diol, glycerol, penta erythritol, phenyl ethyl alcohol and naphthylene-1 : 2- diethyl alcohol.  Numerous suitable esters are specified including vinyl esters and partial esters of polyhydric alcohols.  The reaction of polyhydric alcohols or esters thereof with poly carboxylic acids or anhydrides thereof is also exemplified (see Group IV (a)).