It's also got the carboxylic acid though, so let's go ahead and call it butenoic acid.
不过它也含有羧酸, 所以让我们继续称之为丁烯酸。
英语百科
Crotonic acid
Crotonic acid, or trans-2-butenoic acid, is a short-chain unsaturated carboxylic acid, described by the formula CH3CH=CHCO2H. Crotonic acid is so named because it was erroneously thought to be a saponification product of croton oil. It crystallizes as needles from hot water.