Patent GB-714501-A (GB)
Title: Improvements in or relating to polyvinyl ester-ester interchange process
IPC: C08F8/14
Filed: 1951-06-13
Abstract: Polyvinyl esters of organic acids are prepared by reacting an initial polyvinyl ester with a primary alcohol ester of an organic acid different from the acid from which the initial ester is derived, at a temperature not greater than 120 DEG C. in the presence of a solvent and an esterinterchange catalyst.  The process is particularly applicable to the production of polyvinyl esters of natural oils, including drying, semi-drying and non-drying vegetable and animal oils.  Suitable catalysts are alkali metal alcoholates, organo compounds, and anhydrides and the finely divided metals themselves. The organo-metal compounds are preferably obtained by dissolving the metal in a mixture of a polycyclic aromatic hydrocarbon and an ether, particularly a tetrahydrofuran derivative.  These catalysts apparently decompose forming the true catalysts in situ.  The esters which are reacted with the polyvinyl esters include those of the monohydric primary alcohols and fatty acid esters of glycols and their ethers, glycerols and furfuryl alcohols.  They may be cyclic or acyclic, saturated or unsaturated, substituted and unsubstituted. These esters, particularly the low molecular weight fatty acid esters of low aliphatic alcohols, may also be used as reaction promoters and the acid radicals of these esters and of the polyvinyl esters are preferably the same.  The reaction medium may also comprise these esters and, in addition, low molecular weight fatty acid esters of secondary and tertiary alcohols.  Other solvents include hydrocarbons, amines, carbonyl compounds, sulphides, and, for preference, ethers, including acetals, ketals and lactones.  The degree of reaction may be controlled by removing from the mixture during the reaction the by-product ester formed, e.g. by controlling temperature and pressure to cause the ester to distil out.  Air and moisture are preferably excluded from the reaction mixture and the catalyst may be added batchwise or incrementally during the reaction. The initial polyvinyl ester may be a homo- or co-polymer derived from a mono-or poly-basic, saturated or unsaturated, substituted or unsubstituted, straight or branched chain, cyclic or acyclic, alkyl, aryl or alkaryl acid.  In the Examples: (1) polyvinyl acetate is heated with coconut oil methyl esters in the presence of ethoxy ethyl acetate, ethylene glycol ethyl ether acetate, sodium methoxide and sodium hydride, to give a reddish-yellow viscous oil; (2) and (3) polyvinyl esters of linseed oil fatty acids are prepared from the acetate and the methyl esters of linseed oil in methyl acetate; (4) mixed esters are formed by heating polyvinyl acetate with the methyl esters of coconut and linseed oils; (5) china wood oil methyl esters are heated with polyvinyl acetate in the presence of methyl acetate and triacetin: in Example 6, the replacing ester is methyl stearate; in (7), a mixture of methyl methacrylate and soybean oil; (12) methoxyethyl esters of lard; (15) furfuryl esters of soybean fatty acids; (19) cottonseed oil; (20) tributyrin; (26) methyl phenyl acetate (giving a mixed ester of acetic and phenyl acetic acids); (27) methyl anisate; (28) (a) methyl benzoate and (b) furoate; (29) (a) dimethyl succinate and (b) dimethyl adipate; (30) partially hydrogenated sardine oil.  In Example 31, a copolymer of vinyl acetate and allyl acetate is heated with soybean methyl esters; (32) polyvinyl ester of lard fatty acids is reacted with dimethyl phthalate.  The invention also comprises, as new materials, esters derived from a polyvinyl alcohol containing at least 25 OH groups, in which at least 25 per cent. of these groups are esterified by a mixture of higher fatty acid radicals, which mixture contains not more than 20 per cent. of radicals of fatty acids normally solid at a temperature of 65 DEG C., and 15 to 50 per cent. of radicals of acids normally solid at 45 DEG C., and in which the only acyl radicals are of monocarboxylic acids.  The first group of acids includes those having 18 or more carbon atoms, e.g. stearic, nonadecanoic, arachidic and behenic acids.  The second group include those having more than 13 carbon atoms, e.g. myristic, pentadecanoic and palmitic acids. These acids may be substituted.  As a source of the mixture of acids may be used natural fats, e.g. sardine, herring and menhaden oils, palm, cotton seed, sheabutter and peanut oils and hog fat.  The marine oils are preferably partially hydrogenated.  The balance of the hydroxy groups of the polyvinyl alcohol may be esterified by any monocarboxylic acid, preferably one having less than 10 carbon atoms, e.g. acetic, chloroacetic, propionic, n- and isobutyric, n- and iso-pentanoic, hexanoic, heptanoic, 2-ethyl hexanoic and pelargonic acids, and unsaturated acids such as acrylic, methacrylic, butenoic, &c., acids.  Other acids mentioned are benzoic, dichlorobenzoic, toluic and furoic acids.  These esters may be prepared by the above interchange process or by any other method.  The products vary from oils, many of which are good drying oils, to resin-like materials, and they remain clear and do not form crystals at low temperatures.