GB331542A - Improved method of treating tars - Google Patents

Abstract

331,542. Morgan, G. T., Sinnatt, F. S., and Pratt, D. D. Feb. 4, 1929. Pitch and tar.- Products consisting substantially of resins of phenolic, carboxylic acid, basic. and neutral characters are separated from pitch, which term includes the insoluble portion left by treating tars with light petroleum, by extracting the pitch with a solvent such as ether. benzene, or low temperature tar spirit, separating the solution from undissolved matter, and then precipitating the solution with petroleum, or evaporating the solvent from it. The solution may be separated into its four constituent resins by the following steps :-(1) Extraction with caustic soda solution or caustic soda and brine, followed by carbonation and acidification to obtain resinols and resinoic acids. (2) Extraction. with mineral acids followed by decomposition with alkali to obtain resinamines. (3) Evaporation of solvent to leave a residue of resinenes. The mixture of resins, or the individual fractions. obtained as above are treated with one of the above-named solvents, and the insoluble portions used in stains or lacquers, or in the preparation of moulded articles; the dissolved portion is reprecipitated with petroleum, whereby solid amorphous resins are obtained. In an example, low temperature tar is extracted with petroleum,. and the precipitated pitch is dissolved in ether. benzene, low temperature tar spirit, or the like; the solution is treated with aqueous caustic soda, or with caustic soda and brine to remove resinols. and resinoic acids, and subsequently with acid to remove resinamines. The residual solvent is then evaporated to yield resinenes. The crude fractions are purified by solution in organic solvents followed by precipitation with petroleum. In another example, the pitch remaining after a distillation of high or low temperature tar is treated in a like manner. A further example is given in which low temperature tar is extracted with petroleum; the precipitated pitch is extracted with ether, benzene, low-temperature tarspirit, or the like, and the solution separated from undissolved material, and treated with petroleum to obtain a mixture of the four types. of resinous products. Specifications 307,382 and 327,797 are referred to.