PATENTS

3085.----- [RUHRCHEMIE, A. G.]  [Process for Refining the Distillation Residues From the Oxidation of Paraffin.]  German Patent Appl. --, R 652, filed Dec. 30, 1942.  TOM Reel 36, bag 3,454, item 36, 4 pp.; Meyer Transl. PC-S-IV, Wax Oxidation, vol. 1, ch. 16, 1948, p. 41.

In working up the distillation residues from the oxidation of paraffin, the so-called oxide pitch, they are treated repeatedly at increased temperatures with H₂SO₄-alkali bichromate solutions.  This oxide pitch, before treatment with the alkali bichromate-H₂SO₄ mixture, is saponified with an excess of alkali and again acidified with dilute mineral acid.  Example:  100 gm. of a residue from paraffin oxidation are heated to 70° with active stirring with a solution of 125 gm. Na buchromate and 1,250 gm of 40% H₂SO₄.  After the 1^st violent reaction, the temperature is raised to 110° and within an hour the reaction is complete pitch is decanted from the chrome sulfate solution and the treatment repeated with fresh alkali bechromate-H₂SO₄ solution.  After a triple oxidation, a product of greenish color, which can be bleached by a H₂O₂ treatment, is obtained. The product is yellowish brown with a neutralization number of 159, a saponification number of 195, and a hardening point of 78°. The yield of refined oxide pitch amounts to 78%.