The calculated results show that the aza Wittig reaction is a two step reaction, having one four membered ring intermediate on its reactionsurface.
计算结果表明该反应是一个二步反应，在反应途径上存在一个四元环中间体。
2
The skin's protective reaction of constricting surface blood vessels is slower with age, and the cold-induced rise in metabolic rate is also weakened in older people, but the mechanism is unknown.
After two decades, 95 percent of the elemental mercury on the surface of a filling had gone through a chemical reaction. It became beta-mercury sulfide, a black-colored solid.