GB644597A - Mixed esters - Google Patents

Abstract

Mixed esters are prepared by reacting a mixture solely of an unsaturated aliphatic or carbocyclic monocarboxylic acid having 2 to 4 conjugated double bonds, one of which is in conjugation with the carboxyl group, and a dicarboxylic acid as hereinafter defined, at a refluxing temperature not above 170 DEG C., with at least a stoichiometric amount of a polyhydric alcohol in the presence of a strong acid catalyst and a water-immiscible organic solvent capable of vaporizing and entraining the water formed. The unsaturated monobasic acids have the structure <FORM:0644597/IV (a)/1> where the free valencies are satisfied by hydrogen, alkyl, alkenyl or aryl groups. They include sorbic, b -vinyl acrylic, octatrien-(2,4,6)-oic, decatetraen-(2,4,6,8)-oic, b -styryl acrylic, a -methyl or ethyl-sorbic, g -, e - or b -d -dimethylsorbic, a -methyl-g -benzal crotonic acid, 1-ethyl-4-phenyl-1-butadiene (1,3) carboxylic, 2,6-dimethyl-decatriene-(2,4,8)-oic-(10), a ,b -di-isopropylidene-propionic, a -vinyl-cinnamic, a -isopropenyl - cinnamic, and a - isopropenyl - cinnamenyl-acrylic acids. Polyhydric alcohols include alkylene glycols and polyglycols, glycerols and polyglycerols, erythritol and pentaerythritol and their polymers, sorbitol, mannitol, trimethylol-propane, and polyhydroxyethylbenzenes, and are usually added in excess. The dicarboxylic acid is a saturated paraffinic, or otherwise saturated aromatic acid, e.g. succinic, glutaric, adipic, sebacic or phthalic; dimeric sorbic, a dimerized fatty acid or an adduct of maleic acid, and their alkyl and aryl derivatives. Particularly suitable for making esters for bonding laminates are the dicarboxylic acids having 4 or more carbon atoms between the carboxyl radicals. The molar ratio of monoto di-acid may be from 1.5-0.75 for the mono-acid and 2.9-0.05 for the di-acid when glycerol or an alcohol containing more than 3 hydroxy groups is employed. Reaction may be effected in hydrocarbon solution with polymerization inhibitors, and acids such as sulphuric, hydrochloric, perchloric, nitric, and sulphonic acids, boron fluoride or chloride or aluminium chloride. Sulphuric acid is added in about 0.3-3, preferably 1.5-2, per cent by weight of the reactants. Solvents include benzene, toluene, xylene, isobutyl ketone, o-bromo-toluene, diisobutyl ketone, ethyl benzene, and dichloroethyl ether. They preferably comprise 5-25 per cent by weight of the reaction mixture but may reach 75 per cent. Sulphur in an amount of 0.1-0.5 per cent is an efficient inhibitor. Selenium and hydroquinone are also specified. In examples, reaction is effected in an atmosphere of carbon dioxide with refluxing at about 135-140 DEG C., separation of water from condensed solvent and return of the latter. Glycerol is reacted with sorbic acid, and adipic, succinic, or sebacic acid, phthalic anhydride or cyclopentadiene-maleic adduct, toluene being the solvent and sulphuric acid in methanol added to p the refluxing mixture. The esters in film form cure in presence of oxygen and heat. They are used as surface coatings, blending agents for improving hardness of alkyd resins, nitrocellulose lacquers, polystyrene, vinyl acetate-vinyl chloride copolymer and polyvinyl butyral, in varnishes and oils, wrinkle finishes, furniture finishes and as bonding agents for sandpaper or in emulsion form for cloth sizing.ALSO:Mixed esters are prepared by reacting a mixture solely of an unsaturated aliphatic or carbocyclic monocarboxylic acid having 2 to 4 conjugated double bonds, one of which is in conjunction with the carbonyl group, and a dicarboxylic acid as hereinafter defined, at a refluxing temperature not above 170 DEG C., with at least a stoichiometric amount of a polyhydric alcohol in the presence of a strong acid catalyst and a water-immiscible organic solvent capable of vaporizing and entraining the water formed. The unsaturated monobasic acids have the structure <FORM:0644597/IV (b)/1> where the free valencies are satisfied by hydrogen, alkyl, alkenyl or aryl groups. They include sorbic, b -vinyl acrylic, octatrien-(2,4,6)-oic, decatetraen - (2,4,6,8) - oic, b - styryl acrylic, a -methyl or ethyl-sorbic, g -e - or b -d -dimethyl-sorbic, a - methyl - g - benzal crotonic acid, 1 - ethyl - 4 - phenyl - 1 - butadiene-(1,3) - carboxylic, 2,6 - dimethyl - decatriene-(2,4,8) - oic - (10), a ,b - diisopropylidenepropionic, a - vinyl - cinnamic, a - isopropenyl - cinnamic, and a - isopropenyl - cinnamenyl-acrylic acids. Polyhydric alcohols include alkylene glycols and polyglycols, glycerols and polyglycerols, erythritol and pentaerythritol and their polymers, sorbitol, mannitol, trimethylol-propane, and polyhydroxyethylbenzenes, and are usually added in excess. The dicarboxylic acid is a saturated paraffinic or otherwise saturated aromatic acid, e.g. succinic, glutaric, adipic, sebacic or phthalic; dimeric sorbic, a dimerized fatty acid or an adduct of maleic acid, and their alkyl and aryl derivatives. Particularly suitable for making esters for bonding laminates are the dicarboxylic acids having 4 or more carbon atoms between the carboxyl radicals. The molar ratio of monoto di-acid may be from 1.5-0.75 for the mono-acid and 2.9-0.05 for the di-acid when glycerol or an alcohol containing more than 3 hydroxy groups is employed. Reaction may be effected in hydrocarbon solution with polymerization inhibitors, and acids such as sulphuric, hydrochloric, perchloric, nitric, and sulphonic acids, boron fluoride or chloride or aluminium chloride. Sulphuric acid is added to about 0.3-3, preferably 1.5-2 per cent by weight of the reactants. Solvents include benzene, toluene, xylene, isobutyl ketone, o-brom-toluene, di-isobutyl ketone, ethyl benzene, and dichlorethyl ether. They preferably comprise 5-25 per cent by weight of the reaction mixture but may reach 75 per cent. Sulphur in an amount of 0.1-0.5 per cent is an efficient inhibitor. Selenium and hydroquinone are also specified. In examples, reaction is effected in an atmosphere of carbon dioxide with refluxing at about 135-140 DEG C., separation of water from condensed solvent and return of the latter. Glycerol is reacted with sorbic acid, and adipic, succinic, or sebacic acid, phthalic anhydride or cyclopentadiene-maleic adduct, toluene being the solvent, and sulphuric acid in methanol added to the refluxing mixture. The esters in film form cure in presence of oxygen and heat. They are used as surface coatings, blending agents for improving hardness of alkyd resins, nitrocellulose lacquers, vinyl polymers and copolymers, in varnishes and oils, wrinkle finishes, furniture finishes and as bonding agents for sandpaper or in emulsion form for cloth sizing.