Use this URL to cite or link to this record in EThOS: http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.468506
Title: The pyrolysis of some aromatic hydrocarbons
Author: Peacock, S. J.
Awarding Body: University of Surrey
Current Institution: University of Surrey
Date of Award: 1977
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Abstract:
The pyrolyses of benzene and ethyl benzene in a nitrogen carrier in a static system were investigated. Some high temperature/low residence time experiments were also performed with benzene in a flow system. Product analysis was by gas chromatography,. Between 913 and 1053K benzene pyrolyses by a free radical chain mechanism. Hydrogen and diphenyl are the major products. The rate expression /2 dtH2)]/dt = 109'83 exp (-27,100/T) [C6H j mole litre sec applies between 952 and 1030K and may be explained by a simple five-step mechanism. At lower temperatures, the experimental activa- Lion energy is lower than that predicted by theory. Above 1053K, the benzene ring opens and acetylene, ethylene, methane and solid carbon are produced. Many polynuclear hydrocarbons were found to be adsorbed on the carbon and their presence suggests a-mechanism for carbon formation. Pyrolysis of ethyl benzene gives hydrogen and styrene as the major products together with methane, toluene, ethylene, ethane and benzene plus traces of higher molecular weight hydrocarbons. The pyrolysis is a chain reaction with a chain length of the order of 10 initiated by C6H5C2H5 = C6HSCH2 + CH3 for which k- 14.4 exp (-35,300/T) sec-1. This agrees well with previous work involving toluene and aniline carriers. The results may be explained by a complex mechanism involving free radicals, CH3, C6H5CH2, C6H5CHCH3, C6H5CH2CH2, C2H5, C6H5 and H. Termination seems to occur mainly by the disproportionation reaction : 2C6H5 CHCH3 = C6H5CH: CH2 + C6NSCZH5 For the reaction: C6H5CHCH3 = C6H5CH: CIi2 +H a rate constant: ka 1015.9 exp (-26,200/T) sec-1 was deduced.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID: uk.bl.ethos.468506  DOI: Not available
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