Gerald Dennis Dupre

Pyrolysis studies of organic oxygenates: 3. High temperature rearrangement of aryl alkyl ethers

Abstract Thermal chemistry pathways of aryl alkyl ethers have been investigated under coal conversion-like conditions. Anisole is a thermally reactive compound having an oxygen functionality found in such coal precursors as lignins. Pyrolysis of anisoles was carried out using small batch autoclaves. Under thermolysis conditions anisole yielded a product distribution strongly dependent upon experimental parameters. Phenol, methane, CO and benzaldehyde are the low molecular weight products and polyphenyls and polyethers are the predominant high molecular weight products. The generation of CO is explained by a high temperature rearrangement of the phenyl group from O- to C- followed by rapid thermal decarbonylation of the benzaldehyde. Carbon monoxide formation from aryl alkyl ethers can thus be an important mechanistic pathway in coal conversion processes. By investigating the rearrangement using para-fluoroanisole it was shown that this rearrangement proceeds via a three-centered intermediate to para-fluorobenzaldehyde. No meta isomer was observed.

Pyrolysis studies of organic oxygenates. IV. Naphthalene methyl ether pyrolysis under batch autoclave conditions

Aryl alkyl ethers undergo two major kinds of thermal reactions at temperatures of about 450/sup 0/C. They cleave homolytically at the O-C alkyl bond to produce phenols and they cleave homolytically at the C-H alkyl bond, and rearrange to an aryloxy radical leading to carbonyl compounds and ultimately to other products. Results obtained with the methyl ethers of 1- and 2-naphthol and with anisole show clearly that relative kinetics for these pathways differ for different substrates. Unimolecular decomposition rates at 400/sup 0/C and at 450/sup 0/C show that 1-methoxy naphthalene decomposes faster than 2-methoxy naphthalene which in turn is more thermally reactive than anisole.

PYROLYSIS STUDIES OF ORGANIC OXYGENATES VI. THERMAL CHEMISTRY OF LONG CHAIN ALIPHATIC ACIDS

ABSTRACT The thermal chemistry of two long-chain fatty acids, decanoic acid and tetradecanoic acid (myr1st1c add), has been determined at temperatures of 400-450°C under Inert {helium and nitrogen) and reactive (hydrogen) atmospheres. In general the thermal chemistry pathways are similar to those found with aromatic acids. Secondary cracking type reactions were found to be much more Important for the fatty acids, leading to a very complex product mix. As expected, decarboxylation and subsequent radical reactions are Important whether the pyrolysis is carried out In the presence of an Inert gas such as helium or whether a hydropyrolysis occurs. Consistent with what was previously demonstrated with an aromatic acid(7) and an aryl alkyl ether(5), hydropyrolysis suppresses COx formation and tends to generate more aldehydes and alcohols than are produced under conventional pyrolysis conditions. For fatty acids under Inert atmosphere pyrolysis conditions, the major initial products are the alkanes and alkenes d...

Thermal chemistry pathways of esters and ketones

The work described is a continuation of our studies of the thermal chemistry pathways of reactive oxygenates important in fossil fuel hydrocarbons. Esters and ketones are pyrolysis products from carboxylic acids. Ketones have been found to be important components of hydropyrolysis oils from low rank coals, fossil fuels known to contain substantial amounts of carboxylate functionality. 9 references, 1 figure, 4 tables.