The unsaturated link occurs in a cyclic system. 在环体系中存在不饱和键。
Dialkyl quaternary ammonium salts can be used as fabric softeners with high performance, their biodegradation can be improved by inducing unsaturated bond into their alkyl chain. 摘要双烷基季铵盐类产品是一种性能优良的织物柔软剂,如果在烷基链中引入不饱和键,就会提高其生物降解性。