Carbon Disulfide Insoluble Constituents

Determination of the composition of resids and asphalt has always presented a challenge because of the complexity and high molecular weights of the molecular constituents. The principle behind composition studies is to evaluate resids and asphalt in terms of composition and performance. 

In the methods, a sample is digested at 95°C (203°F) for 25 minntes and then extracted with hot toluene in an alnndnm thimble. The extraction time is 18 hours (ASTM D4072) or 3 hours (ASTM D4312). The insoluble matter is dried and 

In procedure A, a sample is mixed with pentane and centrifuged, after which the resid or asphalt solution is decanted and the precipitate is washed twice with pentane, dried, and weighed. For toluene-insoluble constituents, a separate sample of the resid or asphalt is mixed with pentane and centrifuged. The precipitate is washed twice with pentane, once with toluene-alcohol solution, and once with toluene. The insoluble material is then dried and weighed. In procedure B, procedure A is followed except that instead of pentane, a pentane-coagulant solution is used. 

Many investigations of relationships between composition and properties take into account only the concentration of the asphaltene constituents, independent of quality criterion. However, a distinction should be made between the asphaltene constituents that occur in straight-run resids and those that occur in blown asphalts. Remembering that asphaltene constituents are a solubility class rather than a distinct chemical class means that vast differences occur in the makeup of this fraction when it is produced by different processes. 

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Properties Pungent taste and odor usually nearly colorless when fresh but becoming darker and thick on exposure to the air. Optically active, d 0.850-1.100. Soluble in alcohol, carbon disulfide, carbon tetrachloride, chloroform, petroleum ether, and fatty oils insoluble in water except for individual constituents of some oils which may be partially water-soluble, resulting in a loss of these constituents during steam distillation. 

Carbenes n. Constituents of bituminous type products, which are insoluble in the chlorinated hydrocarbons, carbon tetrachloride and chloroform, but soluble in carbon disulfide. 

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