Report upon the forestry investigations of the of agriculture1877-1898 . oduced probably by atmospheric oxidation during- collection ofturpentine. ANALYTICAL WORK. As both the rosin and the volatile oil are easily soluble in chloroform, ether, carbon disulphide,etc., their separation from wood by any of the above solvents would appear to be an easy an exact quantitative determination of the volatile oil ijresents considerable difficulties, andfor these reasons: (1) Wood can not be dried free from moisture without driving ott some of thevolatile hydrocarbons; (2) the et
Report upon the forestry investigations of the of agriculture1877-1898 . oduced probably by atmospheric oxidation during- collection ofturpentine. ANALYTICAL WORK. As both the rosin and the volatile oil are easily soluble in chloroform, ether, carbon disulphide,etc., their separation from wood by any of the above solvents would appear to be an easy an exact quantitative determination of the volatile oil ijresents considerable difficulties, andfor these reasons: (1) Wood can not be dried free from moisture without driving ott some of thevolatile hydrocarbons; (2) the ether extract can not be freed entirely from either without some lossof the volatile oil. If a weighed quantity of wood shavings is exhausted with either, the residue dried at 100° weighed, the total loss thus found will represent: The moisture = H. The rosin = R. The volatile hydrocarbons = T. It is suSicient to determine two of these factors; the third could then be determined bydifference. But as has been mentioned before, the ether extract can not be obtained in any degree. rg^ Fig. S5.—Method uf lOiemiral analysis of Inrpentine. of purity without loss of turpentine. The evaporation of ether in a stream of dry air, as proposedby Dragendorf, for the estimation of essential oils in general, does not give satisfactory resultswith turpentine oil, as Dragendorf himself observed. A weighed quantity of a mixture of rosin and oil, made up in about the same proportions asthey exist in crude turpentine, was dissolved in a suitable amount of ether. The latter was thenevaporated in a current of dry air till the odor of ether was hardly noticeable. The mixture wasfound to have gained considerably in weight by retaining ether in the thick sirupy oleorosin. Itwas only by heating at 100° 0. for some time that all of the solvent could be driven off, and thenthe mixture was found to have lost in weight. Repeated trials proved that this method could notbe used safely. An attempt was t
Size: 2822px × 886px
Photo credit: © The Reading Room / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1800, bookdecade1890, booksubjectforestsandforestry
