Patent GB-821998-A (GB)
Title: Solvent extraction process
Inventor: BLOCH HERMAN SAMUEL
IPC: C10G21/16
Filed: 1958-05-07
Abstract: Mixtures of organic compounds containing hydrocarbons are separated into relatively more and less polar constituents by a solvent extraction process employing as solvent a mixed ether glycol of the general formula HO(C2H4O)x(C3H6O)yH, where x is 1-6 and y is 1-5; the solvent may be employed in conjunction with a secondary solvent.  The process may be applied to the separation from hydrocarbons of organic compounds containing polar groups such as phenols, thiophenols, mercaptans, sulphides, carboxylic acids, nitrocompounds, amines or alcohols, all of which are selectively dissolved in the solvent. Hydrocarbons may be separated from other hydrocarbons, lower molecular weight compounds being more soluble than higher and those of similar molecular weight being decreasingly soluble in the order aromatic, cyclodiolefinic, diolefinic, cyclo-olefinic, olefinic, naphthenic, paraffinic; more unsaturated compounds are more soluble than less unsaturated, e.g. vinyl aromatic hydrocarbons are more soluble than the corresponding alkyl aromatic compounds.  The ratio of x to y in the formula is preferably between 1 and 3 to 1 and the sum of x and y between 2 and 5.  The solvent extraction may be carried out counter-currently at 30-200 DEG  C. under sufficient pressure to keep the mixture and solvent liquid, e.g. 0.5-25 atmospheres gauge with a solvent to mixture liquid volume ratio of 1-30 : 1. Suitable secondary solvents include furfural, furan, furfuryl alcohol, methyl acetate, ethyl acetate, methyl lactate, acetonitrile, nitromethane, nitroethane, nitrobutane and nitrodichloropropane.  Preferred, however, is water in amounts up to 40% by weight of the total solvent.  In stripping dissolved material from the solvent, steam produced by vaporization of the water present may then be the stripping agent.ALSO:Mixtures of organic compounds containing hydrocarbons are separated into relatively more and less polar constituents by a solvent extraction process employing as solvent a mixed ether glycol of the general formula HO(C2H4O)x(C3H6O)yH, where x is 1-6 and y is 1-5; the solvent may be employed in conjunction with a secondary solvent.  The process may be applied to the separation from hydrocarbons of organic compounds containing polar groups such as phenols, thiophenols, mercaptans, sulphides, carboxylic acids, nitro-compounds, amines or alcohols, all of which are selectively dissolved in the solvent.  Hydrocarbons may be separated from other hydrocarbons, lower molecular weight compounds being more soluble than higher and those of similar molecular weight being decreasingly soluble in the order aromatic, cyclodiolefinic, diolefinic, cyclo - olefinic, olefinic, naphthenic, paraffinic; more unsaturated compounds are more soluble than less unsaturated, e.g. vinyl aromatic hydrocarbons are more soluble than the corresponding alkyl aromatic compounds.  The ratio of x to y in the formula is preferably between 1 and 3 to 1 and the sum of x and y between 2 and 5.  The solvent extraction may be carried out counter-currently at 30-200 DEG  C. under sufficient pressure to keep the mixture and solvent liquid, e.g. 0.5-25 atmospheres gauge with a solvent to mixture liquid volume ratio of 1-30 : 1. Suitable secondary solvents include furfural, furan, furfuryl alcohol, methyl acetate, ethyl acetate, methyl lactate, acetonitrile, nitromethane, nitroethane, nitrobutane and nitrodichloropropane.  Preferred, however, is water in amounts up to 40 per cent by weight of the total solvent.  In stripping dissolved material from the solvent, steam produced by vaporization of the water present may then be the stripping agent.