Synthesis of an Odorant Substance for Liquid Petroleum Gas (LPG) as a Substitute for Thiophene (Tetrahydrothiophene)

Abstract

Tetrahydrothiophene (C₄H₈S) is used as an odorant for liquid gas (LPG).the Tetrahydrothiophene acts as an alarm when a leak occurs in liquid petroleum gas (LPG) bottles at a gas filling and distribution company. where it is added at a concentration of (20PPM) to the liquefied gas.

This research includes the preparation of an alternative substance to (tetrahydrothiophene C₄H₈S). ethanethiol (C₂H₅SH), that is used as an odorant for gas leaks. It was prepared in the laboratory at the Petroleum Research and Development Center through the reaction of hydrogen sulfide gas (H₂S) with ethanol alcohol (C2H₅OH) in the presence of a catalyst (Gama alumina) .at a temperature of (350-400 °C) using the reactor or the system that was manufactured Inside the petroleum research and development center.

The prepared substance was identified using various techniques including the (FT-IR) technique to identify the functional groups. In FTIR the thiol group (SH) clearly appeared at a frequency of (2500 cm-1) with the disappearance of the hydroxyl stretching band, which usually appears at a frequency of (3300Cm-1).

The density test for the prepared substance was also conducted using a digital density measuring device inside the laboratories of the petroleum Research and Development Center. The result was 0.8452 g/cm3 at the standard temperature (15.6 ^○C).

The (GC-Mass) assay technique was also used, which is considered one of the most important identification tests and works to give the synthetic formula of the substance. A chart with the highest signal intensity was obtained, which is (62) that represents the molecular weight of the prepared substance ethanethiol (C₂H₅SH) according to what was extracted from the electronic library of the examination device.