Chloromethylation of poly(methylphenylsilane)

The chloromethylation of poly(methylsilane) is readily achieved using chloromethyl methyl ether in a tin(IV) chloride-catalysed reaction in chloroform solution at 0 degrees C. A convenient, less hazardous reaction, in which chloromethyl methyl ether is prepared in situ, is also reported. The accompanying variations of the polymer molecular-weight parameters are recorded for chloromethylations extending to 95% of the substituent phenyl groups, and discussed in terms of chain scissions arising at isolated siloxane linkages formed adventitiously during the isolation of the parent polymer.