Thiomercurimetric determination of carbon disulphide, carbonyl sulphide, thiols and hydrogen sulphide by use of 1,3-diaminopropane and tributyltin chloride

Abstract

A new approach to the determination of carbon disulphide and carbonyl sulphide in the presence of each other is based on the reaction with 1,3-diaminopropane (DAP), and titration with o-hydroxymercurybenzoie acid (HMB) before and after the selective decomposition of the COS-derivative at pH 4. Determination of hydrogen sulphide, thiols, carbon disulphide and carbonyl sulphide in the presence of each other in hydrocarbon solvents involves four titrations with HMB, viz. of all compounds after conversion of CS 2 and COS with DAP, of thiols plus H 2S, of the thiols alone after removal of H 2S by extraction, and of CS 2 alone after removal of other compounds by shaking with aqueous alkali. For selective trapping of H 2S, HCN, RSH, CO 2 and CS 2 + COS, the sample gas is passed successively through a potassium antimonyl tartrate filter, a nickel carbonate filter, a tributyltin chloride filter, a bubbler containing 40% potassium hydroxide solution and a bubbler containing a benzene solution of DAP. The analysis is completed by titration with HMB with dithizone or dithiofluorescein as indicator.