POLYMERIZATION REACTIONS IN AN AL(OBU(S))(3)-(COOH)(2) SYSTEM

Reactions in an Al(OBu(s))(3)-(COOH)(2) (OA)-tetrahydrofuran (THF)/(CD 3)(2)SO (DMSO-d(6)) system (Al(OBu(s))(3):THF:DMSO-d(6):OA = 1:5:5:x, x = 0.01-3) were studied, without the addition of water and the proces s was monitored by NMR. When x less than or equal to 10.3, homogeneous solutions were obtained, whereas white precipitates formed with x gre ater than or equal to 0.7. The formation of sec-butyl alcohol was evid ent with x greater than or equal to 0.6, indicating that oxalate group s coordinate to aluminum to release sec-butyl alcohol. C-13 NMR spectr a of the solutions after 1 day suggest the presence of polymeric speci es if 0.03 less than or equal to x less than or equal to 0.6. The addi tion of a small amount of water resulted in the formation of a white p recipitate (Al(OBu(s))(3):THF:DMSO-d(6):OA:H2O = 1:5:5:0.3:y, y = 0.03 -0.3), indicating that water, possibly formed by esterification in the Al(OBu(s))(3)-OA-THF/DMSO-d(6) system, does not take a major role in the present system.