Coal, distillation INDEX

Free-swelling tests are commonly used to measure a coal s caking characteristics. A sample of coal is packed in a cmcible or tube, without compaction, and heated at a fixed rate to about 800°C. Infusible coals distill without changing appearance or state of agglomeration. The fusible coals soften, fuse, and usually sweU. The profile of the resultant coke is compared to a series of reference profiles so that a swelling index can be assigned. The profiles represent indexes between 0 and 9. The best cokes come from coals having indexes between 4 and 9. 

Indene n. C9H8. Colorless liquid with a Sp gr of 1.006 (20/4°C), mp of 3.5°C, bp of 182°C, refractive index of 1.5726, and a flp of 78.3°C. Insoluble in water, soluble in most organic solvents, rapidly absorbs oxygen from the air, forms polymers by exposure to air and sunlight. Derivation Contained in the fraction of crude coal tar distillates, which boils from 176 to 182°C. Uses Preparation of synthetic resins. 

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