GB496955A - Process for the separation of wax from wax-containing hydrocarbon mixtures - Google Patents

Abstract

Hydrocarbon oils are freed from wax by using as de-waxing solvent pyridine or its homologues in anhydrous form. Preferably dehydrated commercial pyridine of final boiling point 145 DEG C. is used. Pyridine may be mixed with selective solvents such as nitrobenzene, aniline, or chloraniline. After dewaxing, the oil containing pyridine may be treated with aqueous alkali as described in Specification 496,956, to obtain extract and raffinate fractions. In an example, a wax-containing oil is dissolved at elevated temperature in 2 1/2 times its volume of anhydrous pyridine. The solution is then chilled and the precipitated wax is removed by centrifuging, electrodeposition or preferably, filtration. The wax is washed with cold pyridine and the washings added to the filtrate. This is then treated with aqueous alkali to form raffinate, extract, and aqueous layers, which are then separated. The pyridine is recovered from each layer by distillation whereby there is a first obtained a small amount of a distillate of pyridine and water as a constant boiling mixture, then the anhydrous pyridine fraction, leaving a residue of raffinate or extract. The process may be applied to the removal of oil from wax cakes.