GAS-PHASE THERMOLYSIS OF ALLYL PROPARGYL AMINE, ALLYL CYANOMETHYL PROPARGYL AMINE, ALLYL PROPARGYL 2-THIAPROPYL AMINE, AND ALLYL METHANESULFONYL PROPARGYL AMINE

The title amines have been pyrolyzed in a stirred-flow reactor, at temperatures of 360-500-degrees-C, pressures of 7-16 torr, and residence times of 0.5-2.9 s, using toluene as carrier gas. The reaction products were allene, propene, and the corresponding imines. The ratio allene:propene varied in the range 6.7-1.6. The amines with CH2CN and SO2CH3 substituents also formed HCN and SO2. These appear to arise from complex free radical decomposition of the imine product. The first-order rate coefficients for the production of allene plus propene followed the Arrhenius equations: Allyl propargyl amine: k(s-1) = 10(10.07+/-0.31) exp(-133+/-4 kJ/mol RT) Allyl cyanomethyl propargyl amine: k(s-1) = 10(10.73+/-0.30) exp(-146+/-4 kJ/mol RT) Allyl propargyl 2-thiapropyl amine: k(s-1) = 10(12.55+/-0.38 exp(-166+/-5 kJ/mol RT) Allyl methanesulfonyl propargyl amine: k(s-1) = 10(12.56+/-0.34) exp(-184+/-5 kJ/mol RT) Nonconcerted mechanisms, involving polar six center cyclic transition states, are suggested for the elimination of allene and propene. (C) 1994 John Wiley & Sons, Inc.