Patent GB-687841-A (GB)
Title: Removal of sulphur compounds from hydrocarbon oils
IPC: C10G19/08
Filed: 1947-06-11
Abstract: Mercaptides are oxidized by treating with a gas containing free oxygen, such as air, in the presence of an alkaline solution containing preferably 0.01-2 per cent of the tar fraction obtained by the destructive distillation of wood.  Hardwood tar boiling in the range 240-300 DEG  C. is specified, and tars from hickory, beech, maple and oak are mentioned.  The oxidation is preferably carried out at 60-130 DEG  F. and the disulphide layer may be separated from the alkali solution by using a petroleum distillate solvent such as naphtha.  Examples are given of the oxidation of isobutyl mercaptide in sodium hydroxide solution according to the invention; this is compared with the oxidation in the absence of a catalyst or using catechol, hydroquinone or p-aminophenol as catalyst.  Specification 410,115 is referred to.  The Specification as open to inspection under Sect. 91 refers also to hardwood tar obtained from aspen, and to the use of compounds containing 3 hydroxyl groups all attached to a single benzene ring in positions immediately adjacent to each other, and compounds which yield such hydroxy compounds by hydrolysis in alkaline solution.  Compounds specified are pyrogallol, butyl pyrogallol, normal butyro pyrogallol, anthragallol, tannic acid and gallic acid.  The alkaline solutions of the compounds may also contain solubility promotors such as sodium and potassium butyrate, sodium and potassium naphthenates, alkali metal cresylates and the alkali metal salts of the acid oil recovered from alkali solutions used in treating petroleum distillates containing acidic bodies of greater acidity than mercaptans.  This subject-matter does not appear in the Specification as accepted.ALSO:Sulphur compounds are removed from hydrocarbon oils by means of an alkaline solution which is regenerated by blowing with a gas containing free oxygen, such as air, in the presence of preferably 0.01-2 per cent of the tar fraction obtained by the restructive distillation of wood.  Hardwood tar boiling in the range 240 DEG -300 DEG C is specified, and tars from hickory, beech, maple and oak are mentioned.  The regeneration is preferably carried out at a temperature of 60 DEG -130 DEG F, and the disulphide layer can be separated from the regenerated reagent by using a petroleum distillate solvent such as naphtha.  Specification 410,115 is referred to.  The Specification as open to inspection under Sect. 91, refers also to hardwood tar obtained from aspen, and to the use of compounds containing 3 hydroxyl groups, all attached to a single benzene ring in position immediately adjacent to each other, and compounds which yield such hydroxy compounds by hydrolysis in alkaline solution.  Compounds specified are pyrogallol, butyl pyrogallol, normal butyropyrogallol, anthragallol, tannic acid and gallic acid.  The alkaline solutions of the compounds may also contain solubility promoters such as sodium and potassium isobutyrate, sodium and potassium naphthenates, alkali metal cresylates and the alkali metal salts of the acid oil recovered from alkali solutions used in treating petroleum distillates containing acidic bodies of greater acidity than mercaptans.  This subject-matter does not appear in the Specification as accepted.