Thermal Decomposition of Thiophene

Sulfur containing organic compounds contaminate petroleum based fuels as well as bio-fuels. Since the combustion of these organosulfur compounds produces sulfur oxides (SOx), which pollute ecosystems and negatively affect... [ view full abstract ]

Sulfur containing organic compounds contaminate petroleum based fuels as well as bio-fuels. Since the combustion of these organosulfur compounds produces sulfur oxides (SO_x), which pollute ecosystems and negatively affect human health, the EPA requires that the levels of sulfur dioxide, the most common SO_x, cannot exceed 75 parts per billion. As a result, there is great interest in developing and improving the methods for the removal of sulfur contain organic molecules from fuels. The most common of the currently used desulfurization processes, hydrodesulfurization (HDS), is both dangerous and expensive. Additionally, HDS is less efficient at removing aromatic compounds like thiophene and its derivatives. Out of this need for new or improved desulfurization methods, a need for the understanding of the thermal decomposition of various organosulfur compounds arises. We have employed a resistively heated SiC micro-tubular reactor to investigate the thermal decomposition mechanism of the simplest aromatic organosulfur compound, thiophene (C₄H₄S). The unimolecular decomposition products as well as reactive intermediates generated from the thermal cracking of thiophene were characterized via photoionization mass spectrometry (PIMS) and matrix isolation Fourier transform infrared spectroscopy (MI-FTIR).