| 摘要 |
Unsaturated esters are prepared by reacting tertiary olefines having the formula R1R2C=CR3.CH3 wherein R1 and R2 are hydrogen, or substituted or unsubstituted alkyl and R3 is substituted or unsubstituted alkyl with formaldehyde and a carboxylic acid or an anhydride thereof in the presence of a catalyst comprising a metal halide or a salt of a halogenated carboxylic acid with a metal of the second or fourth group of the Periodic Table. As catalysts, zinc dichloracetate and chlorides of zinc, tin, silicon and titanium are mentioned. In examples: (1) trimethylethylene and paraformaldehyde are reacted with glacial acetic acid and with acetic anhydride to give tertiary butanylethylacetate; (2) isobutylene is reacted with trioxymethylene and glacial acetic acid to give isopropenyl ethylacetate. Solvents, e.g. chloroform, ethylenedichloride or ether or desiccants, e.g. sodium or calcium sulphate may be used. Diisobutylene and 2-methylpentene-2 are mentioned as olefines which may be used and propionic, crotonic and phthalic acids are also specified. |
