The Formation of Benzene in the Radiochemical Polymerization of

COh4MUKICATION TO THE EDITOR T H E FORMATION O F BENZENE I N T H E RADIOCHEMICAL POLYMERIZATION OF ACETYLENE In a recent communication Lfund and Rosenblum (J. Phys. Chem. 41, 469 (1937)) reported absorption spectral evidence for the formation of benzene in the radiochemical polymerization of acetylene. The production of benzene appeared to be parallel with the formation of cuprene. Further measurements, performed manometrically after separation of benzene from acetylene, demonstrated that about 20 per cent of the reacting acetylene yielded benzene. This percentage dropped appreciably during the course of the reaction. In view of the fact that benzene itself polymerizes (W, hlund and E. Bogaert : Bull. soc. chim. Belg. 34, 410 (1925)) under the influence of alpha-radiation, the diminishing benzene/cuprene ratio may be due to the succession of polymerizations: 3CzHz CeH6 nCsH6 --$ (CsH6)n --f

To account for the observed rate of formation of benzene, however, the velocity constant ( k p / X of Lind) for the benzene polymerization in the presence of acetylene must be assumed to be about tu-ice as great as for the benzene alone. This greater velocity of benzene disappearance may be due to a catalyzing influence on the part of acetylene which, though not inert, is always present in large excess. CHARLES ROSENBLUX.~ Laboratoire de Chimie Physique University of Louvain Louvain, Belgium 1Fellow of the C. R. B. Educational Foundation.

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