This paper described the preparation of new spiro compound

3

9-dihydro-xyethyl-3'

9'-dibenzyl-1

5

7

11-tetraoxaspiro[5

5]undecane (V) from diethyl malonate methyl chloroacetate and benzyl chloride

The structure of V was confirmed by proton

13C NMR and IR spectra as well as elementary analysis

The cationic polymerization of V was performed in the presence of BF3.O(C2H5)2

Low yields(-10%)of the products were caused by the stabilization effect of tetrasubstituents in the spiro rings.The cationic ring-opening polymenrization mechanism was proposed based on the structures of the obtained polymers.The observed phenomena that the mole ratio of carbonate ester group and benzene group in the polymers decreased as the polymerization temperature increased

and the cross linked polymer was obtained in bulk polymerization were discussed.