Studies on pitch trouble, its cause and its measures to be taken for its prevention (VI)

Abstract

1. It appears that resin composed of resin acid and fatty acid is better and more completely separable into its component two acids by the cyclohexylamine method than by Tschirch's or Twischell's method-each based on the difference in esterization between the two acids.2. The three methods were used in separating the two acids from the oleoresin content of Pinus densiflora and from its heartwood-and sapwood-resin, and the result yielded was practically the same as that given in report 5.3. Oleoresin is composed of a large amount of resin acid andcontains little or no fatty acid. What little resin acid contained in it is not in the form of ester.4. The sapwood resin is mainly composed of fatty acid and of a half or one-third of its quantity of resin acid, either component existing mainly in a free form and partly as ester-an ester composed more of fatty acid ester than resin acid ester. The saturated acids, contained in smallquantities (one-tenth) in the sap-and heartwood, were of two kinds, stearic acid and palmitic acid, and the unsaturated acids consisting of oleic acid and linolie acid, constituted the major part of the fatty acid content.5. The heartwood resin contains a large quantity of resin acid and a smaller quantity of fatty acid than sapwood resin. It exists as free acid, on the whole, with a sure traceable amount of ester mixed with it. The proportion in which saturated-and unsaturated fatty acids are contained in it are about the same as in sapwood resin.6. Pitch and knot resin, which contain ligninsulphonic acid and other substances, preclude the application of the cyclohexylamine method, but either resin recrytalized is easily refined into resin acid in pure crystals by this method.