PRODUCTION AND CHARACTERIZATION OF CARBOXYLIC-ACIDS FROM WOOD .1. LOW-MOLECULAR WEIGHT CARBOXYLIC-ACIDS

Pyrolysis oil from wood has been fractionated directly at the outlets of a multiple hearth reactor using six heat exchangers in parallel. A large portion of the organic liquid phase was recovered in the heat exchangers, and the bulk of the aqueous phase was condensed in a series of cooling traps (secondary condensing unit). The C//1 to C//7 carboxylic acids in the wood pyrolysis oils were analyzed using gas chromatography following conversion into benzyl esters via tetrabutylammonium salts, purification by solvent extraction and silica-gel elution chromatography. The technique of benzylation and purification is an improved carboxylic acid determination method and is more accurate than the other techniques particularly for the quantifications of C//3 to C//7 carboxylic acids. The method of C//1-C//7 acid production of vacuum pyrolysis of wood and the reactor overall separation efficiency are also discussed.