Affirmation of thiol-ene reaction order by FTIR

The photochemical kinetics of the thiol-ene reaction was studied by tracing the change of hydrosulfide group with Fourier transform infrared spectrometry. The results showed that the reaction followed the first-order kinetics for stoichiometric thiol and ene function groups or for excessive ene group using benzophenone as the photosensitizer. The reaction also followed the first-order kinetics with benzoin ethyl ether, benzoin dimethyl ether, benzoin butyl ether or thioxanthen-9-one as the photosensitizer. The results indicated that the reaction of thiol and ene initiated by photosensitizer under ultraviolet radiation is first-order reaction and the reaction rate is in direct ratio to the concentration of thiol.