| dc.description.abstract | The work embodied in this thesis has been broadly classified into four chapters.
Chapter I contains a short introduction to the natural resins and resin oils, briefly summarizing their history and romantic establishment in the paint industry by the discovery of thinners; their general classification with special reference to the Indian resins, their economic utility and the scope of plentiful work in the line. The importance of heat treatment of resins to make them oil soluble has been described. It has been pointed out that the study of resin oil and their mode of formation has thrown considerable light on the process of heat-treatment.
Chapter II deals with the resin Black Damar (Canarium Strictum Roxb) belonging to the damars of Burseraceae family. It occurs widely in the forests of Western Ghats. Though it finds many local uses, it has not been well investigated. The destructive distillation of the resin to obtain the resin oil, the subsequent fractionation of the resin oil and the isolation of a pure sesquiterpene also form the subject matter of this chapter.
On the basis of the work described in Chapter III, the above sesquiterpene has been assigned the following structure. From its molecular refractivity it appeared to be a bicyclic sesquiterpene with two double bonds. On dehydrogenation with sulphur it gave cadalene. The perbenzoic acid kinetics pointed to one exo- and the other endo-cyclic double bonds. On ozonolysis it gave an ?, unsaturated ketone with one methyl keto group. This diketone on Clemmensen’s reduction and subsequent dehydrogenation gave a blue azulene. The monoxide of the sesquiterpene on similar treatment gave a substituted naphthalene.
Chapter IV has been divided into two parts. The first part deals with the isolation of a crystalline compound from the acetone extract of the resin black damar (yield 4.5%). The compound could not be purified by crystallization, sublimation, or adsorption chromatography over alumina and calcium sulphate. During attempts to crystallize the compound a new method for the separation of organic compounds has been developed. This has been discussed in part II, and its application to some known mixtures has been shown.
Using this method a pure sample of the crystalline compound (m.p. 179°C) has been obtained. It is, however, not possible to say anything about the nature of this compound on the face of existing data. Further work in this direction is being done.
In the new method of separation filter paper is used to facilitate fractional crystallization. The general procedure consists of the following two steps:
i) The deposition of the mixture on the filter paper.
ii) Irrigation of the filter paper with a pure solvent, or a mixture of solvents, to obtain separate zones of the components constituting the mixture to be separated. | |
