Investigations of the Photochemistry of Mixtures of Methane, Nitrogen and Ammonia with Lyman-Alpha Radiation

Author: Burke, Jonathan Arno

Year: 1977

Degree: Dissertation (Ph.D.)

Advisor: Kuppermann, Aron

Committee Member: Unknown, Unknown

Option: Chemistry

DOI: 10.7907/pkvs-kt50

Abstract

In an attempt to investigate possible processes which may have led to the formation of nitrogen bases on the primitive earth prior to the emergence of life, the gas-phase photochemistry of mixtures of methane plus nitrogen and methane plus nitrogen plus ammonia was studied. Photolyses were performed with Lyman-a light (10.2 eV). Sample pressures varied from 2.5 T to 10.5 T. The compositions of the starting mixtures were CH4 : N2 = 2.24 : 1, and CH4 : N2 : NH3 = 1 : 0.61 : 0.12, 1 : 0.63 : 0.20, 1 : 0.62 : 0.24 and 1 : 0.64 : 0.96. From 5 X 10-4 to 3.5 X 10-2 of the initial methane was converted into various hydrocarbon products. The products of the methane plus nitrogen photolyses yielded only hydrogen and hydrocarbons as products: no carbon-nitrogen bonds were formed. The products of the methane plus nitrogen plus ammonia photolyses were similar, but with the addition of small amounts of alkyl nitriles and no other carbon-nitrogen products. Hydrocarbon product distributions are in the approximate mole ratio C2H6 : C2H4 : C2H2 : C3H8 : CH3CN - 1 : 0.30 : 0.10 : 0.10 : 0.01. The two products C2H4 and C2H2 exhibited marked pressure dependences. A partial mechanism is proposed.

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