On the Mechanism ofn-Butyl Vinyl Sulfide Formation with [K(18-crown-6)SBu] as catalyst

Abstract

n‐Butyl mercaptane reacts with acetylene in the presence of [K(18‐cr‐6)SBu] as catalyst to give n‐butyl vinyl sulfide. In toluene the reaction is of zeroth order with respect to BuSH and first order with respect to [K(18‐cr‐6)SBu]. The reaction rate depends on the solvent in the following order: toluene > triglyme ≈ BuSH ≈ dioxane ≫ BuOH. In toluene, BuOH added in equimolar amounts accelerates the reaction indicating a complex formation [K(18‐cr‐6) (BuOH)SBu] with a higher catalytic activity. [K(18‐cr‐6)SBu] is monomeric in the solid state with d(K–S) = 3.051(2) Å. Potassium is displaced out of the mean plane defined by the six oxygen atoms of the crown ether by 0.626(3) Å. [K(18‐cr‐6)SBu] is a strong electrolyte in alcohols but practically no electrolytic dissociation takes place in solvents with low dielectric constants such as toluene and n‐butyl mercaptane. From the results a reaction mechanism is derived with the addition of non‐dissociated [K(18‐cr‐6)SBu] to acetylene as the rate‐determining step.

Catalytic Reactions of Acetylene: A Feedstock for the Chemical Industry Revisited

“…121 The vinylation of potassium thiolates in aromatic solvents in the presence of crown ethers at atmospheric pressure and 70 °C has also been reported. 122,123 A very interesting type of sulfur vinylation proceeds when acetylene is reacted under pressure at 100−110 °C with sodium sulfide, H 2 S, or elemental sulfur in DMSO in the presence of KOH and water, from which divinyl sulfide is obtained. The properties and reactions of this compound have been extensively reviewed.…”

C−N, C−S and S−S Bond Cleavage by Rhodium PCcarbeneP Pincer Complexes

“…The molecular structure of [ 2 ] 2 reveals that the η 2 ‐C−S motifs act as μ 2 bridging ligands through sulfur (i. e. μ 2 ‐S), and occupy the coordination positions previously occupied by the monodentate phosphines in 2‐PPh 3 and 2‐PPh 2 (C 6 F 5 ) (Figure ). The coordination of a second rhodium centre to the thiocarbonyl group further elongates the C−S bond distance to 1.797(3) Å, a value closer to C sp3 −S single bond distances …”

An expedient synthesis of methyl vinyl sulfide from dimethyl disulfide and acetylene

“…If the reaction is carried out without N 2 H 4 ·H 2 O, the yield of 2 is drastically decreased (table, entries 9, 10). The use of other reducing agents, such as Zn, Na 2 SO 3 , FeSO 4 and Na 2 S 2 O 3 , is of no benefit since the yield of 2 in all cases did not exceed 39% (table, entries [11][12][13][14]. The second step of the process, i.e.…”

“…Most known syntheses of alkyl vinyl sulfides are based on reactions of acetylene with thiols, which are usually carried out either as a classic version (100-160 • C; pressure of acetylene up to 35 atm; alkali metal hydroxides, alcoholates or thiolates as catalysts) [9,10], or in a non-hydroxylic polar solvent (HMPA; DMSO; 20-80 • C; atmospheric or elevated pressure) [11,12], or in hydrocarbons with KOR and crown ethers as phase-transfer catalysts [13,14]. At the same time, direct vinylation of methanethiol (which has a bad stench and is volatile and, hence, inconvenient to handle) with acetylene has not been described so far, although there was a single example of the preparation of methyl vinyl sulfide in high yield by heating (95-100 • C) methylisothiuronium bromide in the NaOH-water system under an acetylene pressure of 30 atm [15].…”