Allied Corporation

Arthur S Chu

George R Cook

Edward F Bart

Emil J Walerko

David M Horbachewski

Frank Scarcello

A novel coal tar based, low solids content, pitch is produced by oxidizing a selected coal tar distillation fraction with air to oxygen at elevated temperatures. This pitch is applicable to end use in which low solids content is desirable. Specifically it may be advantageously applied to the impregnation of carbon electrodes. The oxidized selected coal tar based low solids material described is characterized by high carbon yield and higher product density and has a higher in situ coking value and lower sulfur content which make it particularly beneficial when it is used as an impregnating pitch as compared to the currently commercially used petroleum based pitch.

Low solids content, coal tar based impregnating pitch

A driveway sealer less affected by temperature extremes can be made from an oxidized coal tar distillation cut. The sealer incorporates a middle cut crude distillate which is oxidized to produce a product of desired viscosity. The sealer incorporating this oxidized middle cut is less affected by extremes in weather as compared to regular sealer tar. It has more consistent physical properties. A significant distinguishing characteristic derived from the use of this tar in a driveway sealer is the reduced odor of the resulting sealer. The oxidation (condensation) step is carried out at elevated temperature by sparging copious quantities of air rapidly into the tar at elevated temperatures of the order of about 300.degree. F. to 800.degree. F. (200.degree. C.-430.degree. C.).

Tar fraction for driveway sealers using oxidized coal tar distillate

Mixtures including ethyl tetrahydrofurfuryl ether (ETFE), tetrahydrofurfuryl alcohol (THFA), ethanol and water, and usually also an ethyl halide, are extracted with an aqueous solution of an alkali metal or alkaline earth metal chloride salt until THFA/ETFE ratios below 0.01 or 0.001 are achieved. Thereby THFA and ethanol, each of which are difficult to separate from ETFE by distillation, are removed.

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E. Amherst, NY, United States of America

Arthur S Chu