74-93-1Relevant articles and documents
New method of dimethyl sulfi de synthesis
Mashkina
, p. 678 - 681 (2011)
The synthesis of dimethyl sulfide consists in the reaction of dimethyl disulfide with methanol in the presence of solid catalyst, aluminum γ-oxide. The yield of dimethyl sulfide grows with growing temperature, contact time, and content of methanol in the reaction mixture. At 350-400°C, molar ratio methanol-dimethyldisulfide 2.0-2.5, and total conversion of the reagents the yield of dimethyl sulfide reached 95 mol%. Pleiades Publishing, Ltd., 2011.
Pre-steady-state kinetic and structural analysis of interaction of methionine γ-lyase from Citrobacter freundii with inhibitors
Kuznetsov, Nikita A.,Faleev, Nicolai G.,Kuznetsova, Alexandra A.,Morozova, Elena A.,Revtovich, Svetlana V.,Anufrieva, Natalya V.,Nikulin, Alexei D.,Fedorova, Olga S.,Demidkina, Tatyana V.
, p. 671 - 681 (2015)
Methionine γ-lyase (MGL) catalyzes the γ-elimination of L-methionine and its derivatives as well as the β-elimination of L-cysteine and its analogs. These reactions yield α-keto acids and thiols. The mechanism of chemical conversion of amino acids includes numerous reaction intermediates.The detailed analysis of MGL interaction with glycine, L-alanine, L-norvaline, and L-cycloserine was performed by pre-steady-state stopped-flow kinetics. The structure of side chains of the amino acids is important both for their binding with enzyme and for the stability of the external aldimine and ketimine intermediates. X-ray structure of the MGL·L-cycloserine complex has been solved at 1.6 A? resolution. The structure models the ketimine intermediate of physiological reaction. The results elucidate the mechanisms of the intermediate interconversion at the stages of external aldimine and ketimine formation.
Crawley, B.,Griffith, H.
, (1938)
Catalytic synthesis of methanethiol from CO/H2/H2S mixtures using α-Al2O3
Zhang, Baojian,Taylor, Stuart H.,Hutchings, Graham J.
, p. 471 - 476 (2004)
Sustained synthesis of methanethiol from the reaction of CO/H 2/H2S mixtures is reported and discussed. Surprisingly, unmodified α-Al2O3 gives the best results for this reaction and methanethiol selectivities of > 98% at CO conversions of ca. 6% can be readily obtained (CO:H2:H2S = 4:5:1, 340°C, total pressure = 20 bar, 200 h-1). Reaction of CO+ H2 (CO:H2 = 1:1) in the absence of H2S using α-Al 2O3 under comparable conditions gives a lower CO conversion (ca. 1.3%) with significant selectivities to methane (20%), methanol (28.5%) and ethanol (21.1%). When H2S is added to the synthesis gas feedstock, the product selectivity switches to sulfur-containing products, almost exclusively methanethiol, but some by-product thiophene is also observed. A range of other catalysts were also investigated (e.g., γ-Al 2O3, Cr2O3, Cr2O 3/Al2O3, Cu/Cr2O3) but all give inferior catalytic performance when compared with α-Al 2O3. The mechanism of the synthesis of methanethiol is discussed, based on a modification of chain propagation in the Fischer-Tropsch synthesis reaction.
Coope,Bryce
, p. 768 (1954)
Metal Oxides as Catalysts for the Reaction between Methanol and Hydrogen Sulfide
Ziolek, M.,Kujawa, J.,Saur, O.,LaValley, J. C.
, p. 9761 - 9766 (1993)
The reaction between methanol and hydrogen sulfide leading to the formation of methanethiol and dimethyl sulfide has been studied using different H2S:CH3OH molar ratios (0.5:1, 1:1, 2:1) at 623 K on various metal oxides presenting different acidity and basicity.The correlations between activity and selectivity of catalysts and their average oxygen and cation charges as well as the strength of their acidic and basic sites, determined by adsorption of probe molecules followed by IR spectroscopy, are as follows: (i) the highest strenth of basic sites and the highest negative charge on oxygen (MgO) lead to the lowest activity and the highest selectivity toward CH3SH; (ii) the lowest strength of basic sites (medium oxygen charge) and the highest cation charge (γ-Al2O3) cause the highest activity and the highest selectivity toward (CH3)2S.The dimethyl sulfide selectivity is in the reverse order of the number of basic sites.IR measurements show that the reaction occurs between chemisorbed methanol (methoxy species) and SH(1-) species or/and H2S molecules.Too strongly held methoxy species as on MgO and PO4(3-)/SiO2 do not react with H2S.The difference in activity and selectivity of both titania samples (anatase and rutile) is discussed.
BORON CONTAINING COMPOUNDS AND THEIR USES
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Paragraph 0254; 0255, (2020/03/29)
The present disclosure contemplates novel boron-containing compounds and their uses as active agents that exhibit pesticidal activity such as antimicrobial, insecticidal, arachnicidal, and/or anti parasitic activity. An agrochemical composition containing such a compound and its use in, animal health, agriculture, or horticulture is also contemplated. A method for promoting plant performance and/or controlling, reducing, preventing, ameliorating, or inhibiting microbes, insects, arachnids, and/or parasites on or in an animal, a plant, a plant part, plant propagation material, and/or harvested fruits or vegetables is also contemplated.
The role of weak Lewis acid sites for methanol thiolation
Weber-Stockbauer, Manuel,Gutiérrez, Oliver Y.,Bermejo-Deval, Ricardo,Lercher, Johannes A.
, p. 509 - 516 (2019/01/28)
Weak Lewis acid sites combined with strong base sites of Cs+ supported on WS2 and γ-Al2O3 act as active sites in the thiolation of methanol. The acid-base pairs dissociate methanol upon adsorption. The formed surface alcoholate and the corresponding sulfuryl groups enable the substitution of oxygen for sulfur in a Langmuir-Hinshelwood mechanism. Stronger Lewis acid sites catalyze dimethyl ether formation via the Eley-Rideal mechanism in which methoxy groups react with gas phase methanol. The results demonstrate the importance of adjusting the acid-base strength in oxides to selectively catalyze substitution reactions.
