Medicine intermediate N - ethylethylenediamine ( NEED ) was synthesized from acrylamide and ethylamine by addition reaction and Hofmann rearrangement.以丙烯酰胺为起始原料,经乙胺加成后,再经Hofmann重排两步反应后合成了药物中间体N - 乙基乙二胺 ( NEED )....
For added protection choose a lipstick with a sun screen.选择防晒护唇膏来增强保护。Protection of sites, habitats and landscapes is of uppermost priority.保护遗址、栖息地和风景区是重中之重。Your arms and legs need protection from light bouncing off gla...