Earlier investigations are reported on the decomposition of diazomethane in ethereal solution, in the presence of gold chloride as a catalyst: these have shown that the catalytic activity in obtaining polymethylene from the diazo compound is due to gold metal.The catalytic action of gold under similar conditions upon diazoethane has brought to the formation of crystalline polyethylidene, obtained by the authors for the first time. The gold surface,,&en, in the present case, exhibits a stereoregulating activity in the reaction.These results led the authors to investigate more thoroughly the polymerizing action of different metal surfaces, prepared as evaporated films, on the first terms of the diazoalkane series.The main results are reported as obtained by following the reaction with the help of chromatographic analyses of the gases, liberated aside of nitrogen. The present remarks have been made:The following metals, in decreasing order of yield, give amorphous polymers : Cu, Ti, Fe, Mg, W, Ni, Mn, V, Ta, Pt, Co, Zn, Cd, Au, Cr, A1 whilst Mo, Pd, Rh, Zr, Ag give practically no polymer, although causing the decomposition of the diazo compound. These experiments are related to diazoethane in ethereal solution. ' ) H. MEERWEIN, Angew. Chem. 60 (1948) 78. 2, A. YA. YAKUBOVICH and V.

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The main results of a kinetic investigation on the formation of amorphous and crystalline polyethylidene from the decomposition of diazoethane catalyzed by colloidal gold are reported.The data on the dependence of the degree of polymerization of amorphous polyethylidene from the initial concentration of diazoethane suggest chain transfer reactions with undecomposed diazoethane as a probable mechanism of termination of the polyethylidene chainse this would be confirmed by the number of the terminal unsaturation in the polymer chain, which has been found to be close to two. The results are in accordance to the previously formulated working hypotheses on the mechanism of the formation of polyalkylidenes from the metal catalyzed decomposition of diazoalkanes. ZUSAMMENFASSUNG:Die Ergebnisse einer kinetischen Untersuchung iiber die Bildung von amorphen und kristallinen Polyathylidenen durch Zersetzung von Diazoathan, katalysiert mit kolloidalem Gold, werden mitgeteilt.Als moglicher Abbruchsmechanismus der Polyathylidenketten wird eine abertragungsreaktion mit unzersetztem Diazoathan diskutiert ; dafur sprechen die Abhangigkeit des Polymerisationsgrades des amorphen PolyHthylidens von der Anfangskonzentration an Diazoathan und die Zahl der endstiindigen ungesattigten Gruppen in der Polymerkette. Damit stimmt die bereits formulierte Arbeitshypothese uber den Mechanismus der Bildung von Polyalkyliden bei der metallkatalysierten Zersetzung von Diazoalkanen iiberein.In two previous papers1s2) we reported some working hypotheses about the path of the reactions leading to crystalline and amorphous polyalkylidenes from the metal catalyzed decomposition of diazoalkanes, as a result of the data obtained from an investigation on the low molecular weight hydrocarbons which are formed in the course of the reaction3) and of the infrared analysis of the polymeric products1S2). In order to prove some of the working hypotheses previously formulated, a kinetic in-