The thermal decomposition of formaldehyde

Abstract

The thermal decomposition of formaldehyde has been studied for comparison with the decomposition of other simple aldehydes. In the decomposition of acetaldehyde the kinetics of the reaction have led to the hypothesis of the existence of a limited number of different activated states of the molecule. It was of interest to determine whether the kinetics for the simpler molecule of formaldehyde correspond to a smaller number of modes of activation. Experimental Results The experimental method was that described previously. Formaldehyde vapour was introduced into the reaction vessel by heating paraformaldehyde. To prevent condensation in parts of the apparatus outside the furnance, all these were kept above 100° C with heated nichrome wire, a special high temperature grease being used for the taps. As the reaction was unaffected by the presence of water vapour (Tables I and Ii) elaborate drying of the formaldehyde was not undertaken. Care was taken to avoid traces of air which interfere with the reaction. The vapour first given off from a fresh sample of parahyde which had been in use for some time.