1,1-Diphenylethylene

1,1-Diphenylethylene is an organic compound with chemical formula. It is a white solid.

Properties

1,1-Diphenylethylene mediates the radical polymerization of methyl acrylate or styrene. Mediation by 1,1-diphenylethylene generates low molecular weight polymer by a termination reaction. Additionally, because 1,1-diphenylethylene has a lower pKa than styrene, it is an effective mediator in the anionic living polymerization of styrene-block-methyl methacrylate copolymers. Polystyrene homopolymers can be "capped" with 1,1-Diphenylethylene before adding methyl methacrylate, effectively adjusting the pKa of the active chain end so that 1,4-addition to methyl methacrylate is favored over 1,2-addition. Dibenzofulvene is an analogue of a 1,1-Diphenylethylene.

1,1-Diphenylethylene is prepared commercially by alkylating benzene with styrene to give 1,1-diphenylethane. This conversion requires a zeolite catalyst. In a subsequent step, this ethane derivative undergoes dehydrogenation:
A laboratory route to 1,1-diphenylethylene entails dehydration of 1,1-diphenylethanol.