| 摘要 |
A process for preparing crystallizable polymethyl methacrylate or a polymethyl haloacrylate comprises effecting polymerization by contacting the monomer at a temperature of -60 DEG -100 DEG C. in an inert atmosphere with a Grignard reagent-ketone complex produced by reacting a Grignard reagent RMgX in which X is a halogen and R is a hydrocarbon radical having 1-18 carbon atoms with a ketone of the formula: <FORM:0873021/IV (a)/1> in which R1, R11 and R111 are hydrogen or hydrocarbon radical having 1-8 carbon atoms, and R1111 is a hydrocarbon radical having 1-18 carbon atoms. Specified haloacrylates are methylfluoracrylate, methyl chloracrylate and methyl bromacrylate. Specified Grignard reagents are methyl magnesium iodide, ethyl magnesium chloride, ethyl magnesium bromide, isopropyl magnesium chloride, phenyl magnesium bromide, phenyl magnesium chloride, benzyl magnesium chloride, cyclohexyl magnesium chloride, tolyl magnesium chloride, p-methylphenyl magnesium chloride and propenyl magnesium chloride. Many suitable ketones are listed and the use of benzolacetophenone and dibenzalacetone exemplified. The complex may be prepared in the presence of a solvent, e.g. ether, dioxane, pentane or benzene, which may be removed by distillation before adding the monomer. The polymerization may be effected in a solvent, e.g. ethyl ether, diisopropyl ether, ethyl isopropyl ether, ethane, propane, butane, pentanes, hexane, heptane, octanes, cyclopentane, methyl cyclo-pentane, cyclohexane, benzene, toluene or xylenes. The products may be freed from catalyst residues by treating with an alcohol, alcoholic hydrochloric acid and water, and are crystalline or become so when steeped in methyl isobutyl ketone or a 5 : 1 methyl isobutyl ketone-hexane mixture. They may be used in the preparation of fibres, films, coatings and lacquers. |
