GB645613A - Method for the separation of wax from crude wax and bitumen - Google Patents

Abstract

Saponifiable waxes and resins are separated from crude waxes or bitumens containing saponifiable waxes and resins by heating the crude wax or bitumen dissolved in a saturated aliphatic alcohol or a compound thereof having a boiling point below 100 DEG C. with an alkali metal hydroxide, and cooling the mixture to cause insoluble wax acid soaps, wax alcohols and any wax hydrocarbons present to separate out from the alcohol while the resin soaps remain in solution. The insoluble waxy substances are then removed from the solution and mixed with an excess of a dilute aqueous solution of a water-soluble acid having a greater affinity than the wax acids for the soap metal, thereby liberating the free wax acids, which together with the free wax alcohols and any wax hydrocarbons are removed from the aqueous solution and treated further in a known manner. The resin soaps and other resinous substances and any higher alcohols and hydrocarbons which are soluble in cold alcohol are recovered from the alcoholic solution and extracted either with water or with an organic solvent such as benzene. For the purpose of obtaining wax products resembling natural waxes, the separated wax acids may be esterified with higher alcohols from the process and/or of some other origin. It is stated that any asphaltic matter settling out from the alcoholic solution after saponification and cooling does so in the form of a solid cake which can readily be separated from the precipitate of wax-like products. In an example, bitumen obtained from an extraction process is dissolved in ethyl alcohol and saponified under pressure with potassium hydroxide. The mixture is then cooled, the precipitate of potassium salts of wax acids, &c. which forms, is filtered off, washed with ethyl alcohol, mixed with water, an excess of sulphuric acid added, and the precipitate of free wax acids thereby formed separated from the aqueous solution. The resinous substances which have remained in solution in the original cold alkaline alcohol solution are recovered by distilling off the alcohol and extracted with benzol. The unsaponifiable portion dissolves in the benzol while the potassium salts of the resin acids remain as a residue. After the separation of the benzol solution of the unsaponifiable portion, the resin acids are liberated from their potassium salts with sulphuric acid. The unsaponifiable portion is recovered from the benzol solution by distilling off the solvent. In the other example the resinous substances are recovered from the alkaline alcohol solution (after saponification and separation of the wax-like substances) by distilling off the alcohol and extracting the residue with cold water which dissolves the salts of the resin acids. The resin acids are then liberated from the aqueous extract with sulphuric acid. The residue insoluble in cold water constitutes the unsaponifiable portion of the resinous substances. Specifications 5999/00, [Class 91], and 402,751 are referred to.