GB226188A - An improved method of purifying commercial benzene - Google Patents

Abstract

Commercial benzene is purified and render stable to light and air by heating to 100-250 DEG C. under a pressure below 100 atmospheres of air or other gas or at 250-500 DEG C. without pressure. The process polymerizes the unsaturated constituents and destroys carbon disulphide and hydrocyanic acid, but leaves the thiophenes. Catalysts such as water, acids, alkalies, metals, or metallic oxides or other compounds may be used to vary the nature of the polymerization residues, a part of which may be obtained in the liquid form by distillation, leaving neutral pitch as a final residue. Lighter coloured residues are obtained by lining the apparatus with lead, tin, or copper, or by adding these metals or their oxides to the oil. In an example crude benzene with a washing loss of 4.65 per cent is heated for 2 hours to 150 DEG C. under a pressure of 20 atmospheres, and the product distilled up to 120 DEG C. The 97.5 per cent passing over has a washing loss of 2.2 per cent. The residue is mostly thiophene. The Specification as open to inspection under Sect. 91 (3) (a) comprises the treatment of crude benzenes by heating for a short time to a high temperature, e.g. 150-400 DEG C., with or without pressure, e.g. 25-75 atmospheres, and with or without a catalyst to vary the nature of the polymerization residues. This subject-matter does not appear in the Specification as accepted. Reference has been directed by the Comptroller to Specifications 123,806 and 223,066.ALSO:Commercial benzene is purified and rendered stable to light and air by heating to 100-250 DEG C. under a pressure below 100 atmospheres of air or other gas, or at 250-500 DEG C. without pressure. The process polymerizes the unsaturated constituents and destroys carbon disulphide and hydrocyanic acid, but leaves the thiophenes. Catalysts such as water, acids, alkalies, metals, or metallic oxides or other compounds may be used to vary the nature of the polymerization residues, a part of which may be obtained in the liquid form by distillation, leaving neutral pitch as a final residue. Lighter coloured residues are obtained by lining the apparatus with lead, tin, or copper, or by adding these metals or their oxides to the oil. In an example, crude benzene with a washing loss of 4.65 per cent is heated for 2 hours to 150 DEG C. under a pressure of 20 atmospheres, and the product distilled up to 120 DEG C. The 97.5 per cent passing over has a washing loss of 2.2 per cent. The residue is mostly thiophene. The Specification as open to inspection under Sect. 91 (3) (a) comprises the treatment of crude oils such as petroleum products, benzenes, and tars from coal or lignite, by heating for a short time to a high temperature, e.g. 150-400 DEG C. with or without pressure, e.g. 25-75 atmospheres, and with or without a catalyst to vary the nature of the polymerization residues. This subject-matter does not appear in the Specification as accepted. Reference has been directed by the Comptroller to Specifications 123,806 and 223,066.