Reaction of Polymeric Organolithium Compounds with Ethylene Oxide in Hydrocarbon Solution: Determination of Extent of Oligomerization

摘要

The functionalization of poly(styryl)lithium with excess ethylene oxide in benzene solution has been reexamined to determine if oligomerization of ethylene oxide occurs under normal conditions. No ~(13)C NMR peaks were observed at δ = 69-70 and 72-73 ppm as expected for a chain end with two ethylene oxide units. These peaks were not observed even when 3.3 equivalents of ~(13)C-labeled ethylene oxide (98 atom % ~(13)C) was utilized. No peak corresponding to two ethylene oxide units at the chain end (at m/z 104n + 210 + 44 Daltons) was observed in the MALDI-TOF mass spectrum of the functionalization product. The main series of peaks (Ag~+-cationized) appeared at m/z 104n + 210, corresponding to the expected C_4H_9 and CH_2CH_2OH end groups with a number average degree of polymerization of n. A small peak ( ca. 3%) corresponding to two ethylene oxide units at the chain end was observed in the mass spectrum of the functionalization product obtained using 10 equivalents of ethylene oxide.