Chemistry:1,1-Diphenylethylene
1,1-Diphenylethylene is an organic compound with chemical formula (C
6H
5)
2C=CH
2. It is a colorless to light orange to yellow clear liquid.[1]
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.[2] 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.[3] Dibenzofulvene is an analogue of a 1,1-Diphenylethylene.[4]
Synthesis
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:[5]
- C
6H
5CH=CH
2 + C
6H
6 → (C
6H
5)
2CHCH
3 - (C
6H
5)
2CHCH
3 → (C
6H
5)
2C=CH
2 + H
2
A laboratory route to 1,1-diphenylethylene entails dehydration of 1,1-diphenylethanol.[6]
See also
- Dibenzofulvene
- Stilbene
References
- ↑ "1,1-Diphenylethylene 530-48-3 | TCI Chemicals (India) PVT. LTD.". https://www.tcichemicals.com/IN/en/p/D0886.
- ↑ Minjian Zhao; Zhifeng Fu; Yan Shi; Wantai Yang (2015). "Polymerization Mechanism in the Presence of 1,1-Diphenylethylene Part 2: Synthesis and Characterization of PMA and PSt". Macromolecular Chemistry and Physics 216 (22): 2202–2210. doi:10.1002/macp.201500249.
- ↑ D. Freyss; P. Rempp; H. Benoît (1964). "Polydispersity of Anionically Prepared Block Copolymers". Journal of Polymer Science Part B: Polymer Letters 2 (2): 217–222. doi:10.1002/pol.1964.110020214. Bibcode: 1964JPoSL...2..217F.
- ↑ Tamaki Nakano; Kazuyuki Takewaki; Tohru Yade; Yoshio Okamoto (2001). "Dibenzofulvene, a 1,1-Diphenylethylene Analogue, Gives a π-Stacked Polymer by Anionic, Free-Radical, and Cationic Catalysts". Journal of the American Chemical Society 123 (37): 9182–9183. doi:10.1021/ja0111131. PMID 11552835. Bibcode: 2001JAChS.123.9182N.
- ↑ EP0742190 A1, BASF, 13 Nov 1996, Process for the Preparation of Diarylethanes
- ↑ Allen, C. F. H.; Converse, S. (1926). "1,1-Diphenylethylene". Organic Syntheses 6: 32. doi:10.15227/orgsyn.006.0032.
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