| 摘要 |
a -b -Olefinically unsaturated monocarboxylic acids are prepared by heating the corresponding b -ether substituted saturated carboxylic acid or a mixture thereof in the liquid phase in the presence of a catalyst consisting of one or more alkali metal and/or alkaline earth metal salts of a b -ether substituted carboxylic acid. The catalyst salts may be of the same acid as the starting material, a preferred group being the b -methoxy-, ethoxy-, propoxy-, butoxy-, pentoxy-, hexoxy-propionic acids and also mentioned are b -ethoxyhydrocinnamic, b -propoxy-a ,a -di-methyl propionic, b -isopropoxy-isovaleric, b -butoxybutyric, b -methoxy caproic, b -ethoxyadipic, b -ethoxy-n-butyl malonic, b -propoxypimelic, b -methoxyvaleric, b -butoxyglutaric, and b -methoxyazelaic acids. The catalyst may be introduced as such or formed in situ. A temperature of 150 DEG C. to 250 DEG C. is preferred and an inert solvent may be present. Examples describe the preparation of acrylic acid. Specifications 691,866, 828,658, 865,880, 879,555 and 890,697 are referred to. |
