GB836837A - Improvements to polymerization products - Google Patents

Abstract

a -Alkyl styrenes in which the alkyl group contains not more than 6 carbon atoms are prepared by the catalytic dehydrogenation of the corresponding iso-alkyl-benzene in the presence of steam or by the dehydration of the carbinols by sodium bisulphate, oxalic acid or anhydrous potassium hydroxide. a -Acyloxystyrenes in which the acyl group has 1 to 6 carbon atoms are prepared by the reaction of acetophenone with the isopropenyl ester of the corresponding acid in the presence of sulphuric or sulphoacetic acid. a -Acetoxystyrene is prepared by the reaction of acetophenone with ketene or crotonaldehyde in the presence of sulphuric acid or by the reaction of styrenebromohydrin with acetyl chloride to give a -acetoxy-b -bromoethylbenzene, which is then distilled with quinoline.ALSO:a -Alkylstyrene and/or an a -acyloxystyrene, 1 to 55% by weight, and a -alkyl methacrylate 45 to 99 weight per cent, are copolymerized at 70 DEG to 160 DEG C. in the presence of 0.1 to 0.8% of a free radical catalyst to give a product having an intrinsic viscosity in dioxane at 25 DEG C. of at least 0.20. The alkyl and/or the acyl group in the styrenes contains not more than 6 carbon atoms, e.g. a -methyl styrene and a -acetoxystyrene, and the alkyl group in the methacrylates contains not more than 4 carbon atoms. Mass, emulsion, suspension or solution methods may be used and the temperature may be increased incrementally. Conventional free radical catalysts are listed and other polymerizable compounds, e.g. acrylonitrile, methacrylonitrile fumaronitrile, styrene, methyl acrylate and other alkyl methacrylates may also be present.