(ISO nternational Standard 5282 Aromatic hydrocarbons -- Determination of sulphur content --- Pitt-Ruprecht reduction and spectrophotometric method Hydrocarbures aromatiques - Dosage du soufre -- Methode par reduction et spectrophotometrie de Pitt-Ruprecht First edition - 1982-01-15 UDC 661.715.4/.7 : 543.42 : 546.22 Ref.No.ISO 5282-1982(E) Descriptors :aromatic hydrocarbon chemical analysis, determination of content, sulphur, reduction analysis, spectrophotometric analysis. Price based on 6 pages or Standardizatior No reproduction or networking permitted without license from IHS Not for Resale Foreword Iso (the International Organization for Standardization) is a worldwide federation of national standards institutes (Iso member bodies). The work of developing Inter- national Standards is carried out through Iso technical committees. Every member body interested in a subject for which a technical committee has been set up has the right to be represented on that committee. International organizations, governmental and non-governmental, in liaison with Iso, also take part in the work. Draft International Standards adopted by the technical committees are circulated to the member bodies for approval before their acceptance as International Standards by the ISO Council. International Standard ISO 5282 was developed by Technical Committee ISO/TC 78, Aromatic hydrocarbons, and was circulated to the member bodies in September 1979. Austria Italy Romania Czechoslovakia Korea, Rep. of South.Africa, Rep. of France LibyanArab Jamahiriya United Kingdom Germany, F. R. Netherlands USSR Hungary Philippines India Poland No member body expressed disapproval of the document. ? InternationalOrganizationforStandardization,1982 Printed inSwitzerland Copyright Intemational Organization for Standardization No reproduction or networking permited without license from IHS Not for Resale INTERNATIONALSTANDARD ISO 5282-1982 (E) Aromatic hydrocarbons - Determination of sulphur content - Pitt-Ruprecht reduction and spectrophotometric method 1 Scope and field of application 4.4 Zinc acetate [zinc ditacetate], 10 g/l solution This International Standard specifies a method for the determi- nation of the sulphur content of aromatic hydrocarbons boiling 4.5 Propan-2-ol, of such quality that the use of different quantities for the blank test (for example 25 and 50 ml) should below200°C. give no difference in absorbance. Otherwise, the blank test shall be carried out using sulphur-free toluene, instructions for The method is directly applicable to sulphur contents of o,1 to the preparation of which are given in the annex. 30mg/kg;highercontentsmaybedeterminedbysuitabledilu- tion of the sample. 4.6 Raney nickel. Alkylsulphones, arylsulphonic acids and arylsulphonates all give incomplete recovery of sulphur. Raney nickel consists of a mixture of 50 ± 5 % nickel and 50 ± 5 % aluminium. Reference The reducing power of the Raney nickel shall be checked 2 regularly, for example by means of a standard sample. Iso 1995, Aromatic hydrocarbons - Sampling. 4.7 Suiphur, standard solution. 3 Principle Weigh, to the nearest 1 mg, about 320 mg of thiophene (purity > 99 %), transfer quantitatively to a 500 ml one-mark Reduction of the sulphur compounds to nickel sulphide with volumetric flask containing 250 ml of the propan-2-ol (4.5), Raney nickel. dilute to the mark with the propan-2-ol and mix. Stripping of the hydrogen sulphide in hydrochloric acid Pipette 25,0 ml of this solution into a second dry 500 ml onie medium and absorption inan alkaline zinc acetate solution mark volumetric flask,dilutetothe mark withthepropan-2-ol Formation ofmethylene blue withN, N-dimethyl-p- and mix. phenylenediamine sulphate and iron() ammonium sulphate. 1 ml of this standard solution contains 3,81 × 10-5 m mg of Determination of the absorbance of the blue coloured solution S, where m is the actual mass, in milligrams, of thiophene atawavelengthof 667nm. taken. 4.8 Iron(lll) ammonium sulphate