Patent GB-582789-A (GB)
Title: Improvements relating to the production of unsaturated hydrocarbon products from petroleum refining residues
Filed: 1944-07-21
Abstract: Vulcanizable unsaturated hydrocarbons obtained from petroleum refining residues, such as acid sludges from sulphuric acid refining or residues from solvent extraction, are separated from paraffinic hydrocarbons by treating with a solvent miscible with the unsaturated hydrocarbons in substantially all proportions at room temperature and below but immiscible at the same temperatures with the paraffinic hydrocarbons, the resulting mixture being cooled, allowed to stratify and the unsaturated hydrocarbons recovered from the lower layer by distillation of the solvent. The solvent is advantageously miscible with the paraffinic hydrocarbons at elevated temperatures, but immiscible at lower temperatures.  Suitable solvents are furfural, phenol, furfuryl alcohol and aniline.  They may be used in admixture with light saturated hydrocarbons of boiling range below that of the unsaturated hydrocarbons, e.g. petroleum ether, gasoline, kerosene, naphtha, hexane or heptane.  The proportion of solvent to material extracted is generally at least 2 : 1 by volume.  With furfural, in batch operation 4 : 1, and in continuous operation 3 : 1 is advantageous.  The solvent desirably contains up to 6 per cent of water.  It may be preferable to mix it with the material at 50-100 DEG  C., and to cool to room temperature or below and settle.  The amount of diluent, if used, is 0.5-10 times the volume of paraffins. It separates as an upper layer containing the paraffins.  The vulcanizable unsaturated hydrocarbons are used in rubber compositions and synthetic resins.  In examples: (1) an extract from the refining of lubricating oil with aniline is treated with 2 parts of aniline, cooled to - 2 DEG  C., stratified, the lower layer distilled to remove aniline, and the residue fractionated.  By treatment at 100 DEG  C. and cooling to room temperature, a better separation is obtained; (2) a residue from the refining of lubricating oil with sulphur dioxide-benzol is similarly extracted with furfural at 100 DEG  C. followed by cooling to room temperature; (3) 50 parts of a similar residue are treated similarly with 100 parts of furfural and 6 parts kerosene; (4) an extract from the refining of lubricating oil with furfural is treated with furfural and solvent naphtha at 140 DEG F., using a proportion of furfural to extract of 2 : 1 and of diluent to paraffins of 0.5, 1, 2, 5 and 10 : 1; (5) vulcanizable unsaturated hydrocarbons from an acid sludge produced in the sulphuric acid refining of lubricating oil are diluted with 10 per cent of gasoline and then mixed with 4 parts by volume of furfural at 80 DEG  C., cooled and settled; (6) a residue from the refining of a lubricating oil with propane and cresylic acid is treated with furfural and kerosene at 100 DEG  C.; (7) a similar residue from a refining with furfural is extracted with 1 part of furfural at 100 DEG  C., cooled, settled and the bottom layer again treated with 2 parts of furfural. Alternatively, a continuous counter-current extraction is effected in the presence of gasoline.ALSO:Vulcanizable unsaturated hydrocarbons obtained from petroleum refining residues such as acid sludges from sulphuric acid refining or residues from solvent extraction, are separated from paraffinic hydrocarbons by solvent extraction and used in rubber compositions.