| 摘要 |
PROBLEM TO BE SOLVED: To obtain a polyp-γ-butyrolactone having a higher molecular weight from industrially mass-produced cheapγ-butyrolactone by polymerizingγ- butyrolactone through ring opening by heating to a specified temperature under an ultrahigh atmosphere in the presence of a Lewis acid. SOLUTION:γ-Butyrolactone is polymerized through ring opening by heating to 40-160 deg.C. The Lewis acid used is exemplified by a boron halide, a metal halide, or a metal alkoxide and may be used in the form of a mixture with an organic acid. The amount of the Lewis acid used is usually 0.01-5 mol% based on the amount of theγ-butyrolactone used. The ultrahigh pressure ranges from at least 10,000 atm, desirably, at least 12,000 atm to at most about 20,000 atom. The reaction time is usually 10-70 hr. The molecular weight of the obtained poly-γ-butyrolactone ranges from at least 10,000 to at most, usually, about 50,000.
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