The Effect of Methanol Quenching Agent

Despite the extensive use of methanol as quenching ent in cationic polymerizations, little is known about the chemical reactions which occur during quenching. An observation related to this question is worth mentioning here. 

To a mixture of 12 ml P-pinene and 3 ml methanol at —78°, 3 ml EtAlCl2 was added. After about 10 minutes a viscous oil was obtained. The PMR spectra of the mixtures before and after reaction have been compared. It was found that the methyl proton singlet of methanol had shifted from 3.46 to 3.16 which indicates the presence of a methoxy proton in an ether linkage. According to this finding, the following reaction mi t have occured  

We did not uncover any literature about this ether and could not confirm the spectrum with an authentic sample. 

A detailed structure characterization of isobutylene and 0-pinene copolymers has been carried out including homogeneity studies (by GPC), quantitative composition and sequence analysis (by PMR and reactivity ratios) and molecular weight determinations (by osmometry and viscometry). Analysis of our data leads us to conclude that isobutylene and 0-pinene can be readily copolymerized to reasonably high molecular weight materials and that the products are perfectly random, statistical copolymers showing no detectable tendency for blockiness . 

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