Abstract
Tris(pentafluorophenyl)gallium (3) and aluminum (7) are active coinitiators for the production of medium-high molecular weight (MW) polymers of styrene and isobutene (IB) under aqueous reaction conditions. Strong Brønsted acids formed in situ by reaction of these coinitiators with background moisture present in the monomer droplet (5 and 8, respectively) are believed to be responsible for inducing cationic polymerization of these monomers. Of the two, 7 is the most active for IB polymerization in both aqueous media and anhydrous aliphatic solvents. These results are in contradistinction to tris(pentafluorophenyl)boron (2), which is incapable of polymerizing IB in aqueous or aliphatic media. The MWs of the polyisobutenes (PIBs) produced under aqueous conditions by either coinitiator greatly exceed those formed under similar reaction conditions by the strongly acidic chelating diborane (1,2-C 6F 4[B(C 6F 5) 2] 2, 1) or diborole (1,2-C 6F 4[9-BC 12F 8] 2, 6). Both 3 and 7 are readily synthesized from the corresponding Group 13 halide compounds in conjunction with bis(pentafluorophenyl)zinc (4). Aqueous polymerization of IB dissolved in aliphatic solvents with 3 or 7 can yield PIBs with relatively narrow polydispersities.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 1325-1332 |
| Number of pages | 8 |
| Journal | Journal of Polymer Science, Part A: Polymer Chemistry |
| Volume | 50 |
| Issue number | 7 |
| DOIs | |
| State | Published - Apr 1 2012 |
All Science Journal Classification (ASJC) codes
- Polymers and Plastics
- Organic Chemistry
- Materials Chemistry