Patent GB-765518-A (GB)
Title: A process for desulphurising phenols which are contaminated by organic sulphur compounds
IPC: C07C37/86
Filed: 1955-02-02
Abstract: Phenols which are contaminated by organic sulphur compounds are desulphurized by subjecting them to distillation in the presence of free sulphur and an alkaline material, said free sulphur being present in an amount sufficient to maintain an oxidizing atmosphere in the distillation zone.  The phenols, including alkyl phenols, are preferably those boiling below 240 DEG  C. and they may be obtained from thermally and catalytically cracked petroleum distillates boiling between 100 DEG  and 250 DEG  C. by extracting them with aqueous alkali and then acidifying by carbon dioxide, subsequently the phenols are obtained either by settling, and water washing, or by extraction with diethyl ether.  The free sulphur which may be in the form of alkali metal polysulphides which liberate sulphur in the distillation process or in the form of shavings from a cast stick may be used in an amount of 0.05 to 5.0 per cent by weight based on the phenolic material.  The alkaline material is preferably sodium hydroxide and may be present in an amount between 0.005 and 1.0 per cent based on the alkyl phenols, it may be present as an impurity in the material providing the sulphur such as sodium sulphide.  A preferred sulphur-sodium hydroxide solution is made by heating 16 parts of sodium sulphide nonahydrate, 6 parts of elemental sulphur, 0.1 part of sodium hydroxide and 3 parts of water slowly to the temperature at which a homogeneous solution is obtained.  The distillation is preferably carried out at a pressure less than 50 mms. of Hg.ALSO:Phenols which are contaminated by organic sulphur compounds are desulphurized by subjecting them to distillation in the presence of free sulphur and an alkaline material, said free sulphur being present in an amount sufficient to maintain an oxidizing atmosphere in the distillation zone.  The phenols, including alkyl phenols, are preferably those boiling below 240 DEG C. and they may be obtained from thermally and catalytically cracked petroleum distillates boiling between 100 DEG  and 250 DEG C. by extracting them with aqueous alkali and then acidifying by carbon dioxide, subsequently the phenols are obtained either by settling, and water washing, or by extraction with diethyl ether. The free sulphur which may be in the form of alkali metal polysulphides which liberate sulphur in the distillation process, or in the form of shavings from a cast stick may be used in an amount of 0.05 to 5.0 per cent by weight based on the phenolic material.  The alkaline material is preferably sodium hydroxide and may be present in an amount between 0.005 and 1.0 per cent based on the alkyl phenols, it may be present as an impurity in the material providing the sulphur such as sodium sulphide.  A preferred sulphur-sodium hydroxide solution is made by heating 16 parts of sodium sulphide nonahydrate, 6 parts of elemental sulphur, 0.1 part of sodium hydroxide and 3 parts of water slowly to the temperature at which a homogenous solution is obtained. The distillation is preferably carried out at a pressure less than 50 mins. of Hg.