Synthesis of 2,5-dimethylhexene by isobutene dimerization with H2S co-feeding

• Published in: RSC advances Vol. 13; no. 21; pp. 14097 - 14101
• Main Authors: Watanabe, Ryo, Tanikawa, Riku, Kurosaki, Arisa, Oshima, Kazumasa, Kishida, Masahiro, Verma, Priyanka, Fukuhara, Choji
• Format: Journal Article
• Language: English
• Published: Cambridge Royal Society of Chemistry 10-05-2023; The Royal Society of Chemistry
• Subjects: Chemistry; Dimerization; Hydrogen sulfide; Optimization; Synthesis
• ISSN: 2046-2069; 2046-2069
• DOI: 10.1039/d3ra01324c

This study investigates the effect of hydrogen sulfide (H2S) co-feeding on the synthesis of 2,5-dimethyl-1-hexene, 2,5-dimethyl-2-hexene, and 2,5-dimethylhexane (2,5-DMHs), useful compounds, using the dimerization of isobutene under mild pressure conditions. The dimerization of isobutene did not proceed in the absence of H2S, whereas the desired products of 2,5-DMHs were produced under H2S co-feeding conditions. The effect of reactor size on the dimerization reaction was then examined, and the optimal reactor was discussed. To enhance the yield of 2,5-DMHs, we changed the reaction conditions of the temperature, molar ratio of isobutene to H2S (iso-C4=/H2S) in the feed gas, and the total feed pressure. The optimum reaction condition was at 375 °C and 2/1 of iso-C4=/H2S. The product of 2,5-DMHs monotonously increased by an increment of total pressure from 1.0 to 3.0 atm with a fixed iso-C4=/H2S ratio at 2/1.