GB792614A - Process for removing higher acetylenes from hydrocarbon mixtures - Google Patents

Abstract

Mixtures of hydrocarbons containing at least three carbon atoms are freed from higher acetylenes which are defined as acetylenes containing more than two carbon atoms by treating the condensed hydrocarbons with an aqueous solution of a cuprous salt under pressure and the cuprous salt solution is led in a closed cycle, without relief of pressure, in which cycle the higher acetylenes are converted into liquid and solid polymers. The hydrocarbon mixtures may be for example a cracked mineral oil from which it is desired to extract butadiene. In a preferred process the condensed hydrocarbon mixture obtained from a cracking process is treated with 0.5 to 5 times its volume of a cuprous salt solution at room temperature and 5 to 10 atmospheres pressure with stirring. The cuprous salt solution enriched with higher acetylenes is continuously removed and heated to 80-100 DEG C. for about an hour. The solid polymers formed are filtered off after cooling and the solution is returned to the extraction stage where liquid polymers formed are given up to the hydrocarbon mixture which can then be fractionated. In an example, 1 part by volume of a hydrocarbon mixture containing 1.1 per cent by weight of higher acetylenes is washed with 2 parts by volume of an aqueous cuprous salt solution at 20 DEG C. and 7 atmospheres pressure. The cuprous salt solution contained per litre 3 mols. of cuprous ions, 0.2 mols of cupric ions, 4 mols. of acetic acid and 11 mols. of ammonia. The resultant hydrocarbon contained no higher acetylenes and 0.7 per cent by weight of liquid polymers. The cuprous salt solution was heated to 90 DEG C. for one hour and 0.3-0.4 per cent by weight of the original hydrocarbon feed removed as solid polymers.