GB1050513A - - Google Patents

Abstract

1,050,513. Sulpho esters of acrylic and methacrylic acid. DOW CHEMICAL CO. Feb. 20, 1964 [March 1, 1963], No. 7086/64. Heading C2C. [Also in Division C3] An alkali metal salt of a sulpho ester is obtained by heating a mixture of (a) acrylic acid or methacrylic acid, (b) a dry, particulate alkali metal salt of hydroxyethane-sulphonic acid or of hydroxypropanesulphonic acid, (c) a catalyst which is an aromatic or aliphatic sulphonic acid containing from 2 to 12 carbon atoms and mixtures thereof, and (d) an inert organic solvent capable of forming an azeotrope with water, said azeotrope having a boiling-point from 80‹ to 120‹ C., at an esterification reaction temperature of from 80 to 120‹ C. for a period of time sufficient to completely remove water formed by the esterification reaction as a watersolvent azeotrope distillate and recovering the solid sulpho ester alkali metal salt product. The solid starting material is preferably micropulverized and must be free of water. An excess of about 100 mole per cent of a stoichiometric amount of acrylic or methacrylic acid is preferably used. Specified solvents are toluene and benzene. Suitable catalysts are benzene sulphonic acid, lauryl sulphonic acid and toluene sulphonic acid, or a mixture of C 2-12 alkane sulphonic acids. The catalyst is generally used in an amount equal to from about 0À1 to 10À0 weight per cent of the amount of acrylic or methacrylic acid employed. A polymerization inhibitor is preferably employed such as paramethoxy phenol and hydroquinone. The reaction temperature is preferably in the range from 95‹ to 115‹ C. Examples are given in which the sodium salts of 2-sulphoethylacrylate, 2-sulphoethyl methacrylate and 2-sulphopropylacrylate are prepared. The polymers are copolymers derived from the above compounds are useful as flocculating agents and water thickeners (see Division C3). Reference has been directed by the Comptroller to Specification 840,908.