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Feedstock Preparation
Published in James G. Speight, Handbook of Petrochemical Processes, 2019
However, a strong caustic solution is used to remove mercaptans from gas and liquid streams. In the Merox Process, for example, a caustic solvent containing a catalyst such as cobalt, which is capable of converting mercaptans (RSH) to caustic insoluble disulfides (RSSR), is used for streams rich in mercaptans after removal of H2S. Air is used to oxidize the mercaptans to disulfides. The caustic solution is then recycled for regeneration. The Merox process is mainly used for treatment of refinery gas streams
Liquids Processing
Published in Arthur J. Kidnay, William R. Parrish, Daniel G. McCartney, Fundamentals of Natural Gas Processing, 2019
Arthur J. Kidnay, William R. Parrish, Daniel G. McCartney
If complete sulfur removal is not required, Merox™ can also be used in a fixed-bed catalytic conversion process to convert mercaptans to disulfides. The disulfides remain with the liquid stream. However, the disulfide will pass the Doctor test (GPA Standard 3132-84, 2004), which detects the more reactive sulfur compounds H2S and mercaptans.
Practical and efficient recyclable oxidative system for the preparation of symmetrical disulfides under aerobic conditions
Published in Journal of Sulfur Chemistry, 2021
Chiu Ling Ong, Thorsten Heidelberg, Joon Ching Juan, Nader Ghaffari Khaligh
Organosulfur compounds have been attracted much attention in different fields, such as biology, chemical protection, sulfenylation of enolates, and the preparation of bioactive organosulfur compounds [1–4]. The S–S bond formation is an essential step in the vulcanization, peptide stabilization, and DNA-cleavage [5]. The ‘Merox process’ is employed in the petroleum refinery industry for the thiol removal through the oxidative coupling of thiols to disulfides using NaOH or ammonia [6]. Organic disulfides or disulfanes (R–S–S–R) conventionally prepared by oxidative coupling of thiols or sulfur-containing compounds [5,7], which occasionally leads to the formation of side products such as trimers and polymers [8]. The thiosulfinates, thiosulfonates, and sulfonic acids often may be formed during the oxidation of thiols due to the over-oxidization of products [9]. Thus, the oxidative homocoupling of thiols to disulfides under mild and eco-friendly conditions without over-oxidation is a significant process in organic chemistry and biochemistry [5,10].