Laboratory simulation of natural sulphurization: II. Reaction of multi-functionalized lipids with inorganic polysulphides at low temperatures

Abstract

A number of geochemically relevant model compounds (alkenes, ketones, aldehydes, acids, alcohols and esters) have been subjected to a reaction with sodium hydrogen polysulphide either in one solvent or mediated by a phase transfer reagent. This reaction, referred to as the hydrosulphurization reaction, is regarded as a simulation of a natural sulphurization reaction of functionalized lipids in early stages of diagenesis. Only alkenes, ketones and aldehydes reacted to form organic sulphur compounds. Generally with compounds possessing carboncarbon double bonds an addition reaction took place apparently following the Markovnikov rule. The oxo-group of ketones and aldehydes are substituted by sulphur and polysulphide-linked dimers are formed. Polymers or cyclic sulphides are derived from substrates with more than one functionality depending on the spacing between functionalities. Thermal treatment of a polymeric mixture resulted in the formation of thiophenes. These results can explain the formation of many organic sulphur compounds found in sediments and oils.