Carbohydrate Pyrolysis. II. Formation of Furfural and Furfuryl Alcohol during the Pyrolysis of Selected Carbohydrates with Acidic and Basic Catalysts

Abstract

The pyrolysis of five major carbohydrates, glucose, maltose, cellobiose, amylose and cellulose was studied in an inert atmosphere using a thermogravimetric system coupled with a mass spectrometer. The mass spectra of the evolving gaseous mixture were taken at regular intervals and, utilizing a special computerized evaluation program, the composition of the gases was determined as function of time and decomposition temperature. The results obtained with these five carbohydrates showed considerable qualitative and quantitative differences between their pyrolytic decomposition. This confirms that molecular weight and the type of glucosidic coupling greatly affect the pyrolytic reaction mechanism. Acidic catalysts increased the amount of pyrolytic residue at 450° and the composition of the evolving gaseous mixture was simpler. Basic catalysts did not influence considerably the solid residue, but more complex volatile mixtures were obtained. The products contained a wide variety of alcohols, ketones, aldehydes and other oxychemicals in all cases, among them furfural and furfuryl alcohol as the major components.