The Kinetics and Mechanism for the Substitution of Biphenyloxide for Chloride on Hexaphenyldichlorotetraphosphonitrile

摘要

A study of the kinetics and mechanism of the biphenyloxide substitution for chloride on the hexaphenyldichlorotetraphosphonitrile molecule was conducted. The reaction was studied in sealed, evacuated ampuoles at 210C and in an evacuated gas pressure measuring system at temperatures of 185C and 195C. Two isomers of the expected disubstituted product were isolated by fractional recrystalization from acetonitrile. The isomers had melting points of 204C and 174C. The gas pressure studies provided extent of reaction versus time curves. An analog computer was used to simulate the reaction and the rates obtained were used to determine the Entropy of activation as -42. cal/mole degree K and Enthalpy of activation as 13.6 Kcal/mole for the first substitution. A mechanism consistent with these values is proposed and discussed. (Author)