GB874235A - Unsaturated esters of polyoxyalkylene glycols - Google Patents

Abstract

Acrylic and methacrylic esters of polyoxyalkylene glycols or of their mono-alkyl ethers are prepared by reacting acrylic or methacrylic acid, anhydride, acid halide or ester with the polyoxyalkylene compound, containing, as a stabilizer, a phenolic compound of the formula: <FORM:0874235/IV (a)/1> where R1 is hydrogen, alkyl or alkoxy, and R2 and R3 are hydrogen or alkyl, at least one being alkyl when R1 is hydrogen or alkyl. The stabilized polymers are prepared as described in Specification 874,234. Specified stabilizers are 2, 6- di-tert. butyl-p-cresol, p-hydroxyanisole, 2, 6-di-tert. butyl-phenol, 2-tert. butyl-p-cresol, 2-butyl-p-hydroxy-anisole, 2, 6-dibutyl-p-hydroxy -anisole, and 2, 6-dimethyl-p-cresol. A solvent is generally first added to the stabilized polymer, e.g. toluene, heptane, benzene, cyclohexane, and isopropyl ether. Polymerization inhibitors are also preferably included, e.g. hydroquinone, copper powder, cupric salts and their chelates. Esterification catalysts, such as sulphuric, benzene sulphonic and toluene sulphonic acids, are added, the mixture heated to reflux, e.g. 100 DEG -110 DEG C., and the acrylic compound is added, preferably in slight excess. Oxygen may be introduced when employing reduced pressures and hydroquinone as inhibitor. The product is neutralized with alkaline material and may be washed. Further inhibitor is then preferably added. The examples describe the preparation of: (1) and (2) polyoxyethylene glycol (200) and (300)-dimethacrylate; (3) polyoxyethylene glycol (600)-diacrylate; (4) polyoxypropylene glycol (1869)-dimethacrylate; (5) the monomethacrylic ester of polyoxypropylene-glycol monobutyl ether (3,000).ALSO:Acrylic and methacrylic esters of polyoxyalkylene glycols or of their mono-alkyl ethers are prepared by reacting acrylic or methacrylic acid, anhydride, acid halide or ester with the polyoxyalkylene compound, containing, as a stabilizer, a phenolic compound of the formula <FORM:0874235/IV (b)/1> where R1 is hydrogen, alkyl or alkoxy, and R2 and R3 are hydrogen or alkyl, at least one being alkyl when R1 is hydrogen or alkyl. The stabilized polymers are prepared as described in Specification 874,234. Specified stabilizers are 2,6-di-tert.butyl-p-cresol, p-hydroxyanisole, 2,6-di-tert.butyl phenol, 2-tert. butyl-p-cresol, 2-butyl-p-hydroxy-anisole, 2,6-dibutyl-p-hydroxyanisole and 2,6-dimethyl-p-cresol. A solvent is generally first added to the stabilized compound, e.g. toluene, heptane, benzene, cyclohexane and isopropyl ether Polymerization inhibitors are also preferably included, e.g. hydroquinone, copper powder, cupric salts and their chelates. Esterification catalysts, such as sulphuric, benzenesulphonic and toluenesulphonic acids, are added, the mixture heated to reflux, e.g. 100 DEG -110 DEG C., and the acrylic compound is added, preferably in slight excess. Oxygen may be introduced when employing reduced pressures and hydroquinone as inhibitor. After neutralising with alkaline material and optional washing, further inhibitor is preferably added. The examples describe the preparation of: (1) and (2) polyoxyethylene glycol (200) and (300)-dimethacrylate; (3) polyoxyethylene glycol (600)-diacrylate; (4) polyoxypropylene glycol (1869) - dimethacrylate; and (5) the monomethacrylic ester of polyoxypropylene glycol monobutyl ether (3000).