Methan thiol

SSIMS has also been used to study the adsorption of propene on ruthenium [3.29], the decomposition of ammonia on silicon [3.30], and the decomposition of methane thiol on nickel [3.31]. 

Ben2yloxyindolyl-3)-Q -acetvlamino-Q -methylthiopropionic acid methane-thiol ester Hydrogen Sulfuric acid... 

Figure 3 SC BO emission spectra obtained in the reaction of methane thiol with 03 at 620 mtorr in He (a) 9 mtorr 03, 3 mtorr CH3SH (b) 15 mtorr 03, 7 mtorr CH3SH (c) 20 mtorr 03, 7 mtorr CH3SH (d) 30 mtorr 03, 15 mtorr CH3SH. (Reprinted with permission from Ref. 27. Copyright 1981 American Chemical Society.)...

The chemiluminescent reaction with chlorine dioxide provides a highly sensitive and highly selective method for only two sulfur compounds, hydrogen sulfide and methane thiol [81]. As in the flame photometric detector (FPD), discussed below, atomic sulfur emission, S2(B3S -> ) is monitored in the wave-... 

Af-(Silylmethyl)thioimidates (34) also undergo water-induced desilylation leading to the N-protonated azomethine ylides (38). These ylides react with a range of electron-deficient alkenes and alkynes, aldehydes, and ketones followed by elimination of methane thiol to give formal nitrile ylide adducts (e.g., 40) (23,24). The reactivity of these species is rather dependent on the nature of R (e.g., good for R = Ph but less so for R=Et or i-Pr), which may be due to competition from tautomerization to give the A -methylthioimidate (39). 

Methionine Methional, methane-thiol, 2-propenal Vegetable-hke aromas... 

In the sample of parsley (Table 16.5), the analysis was started with a head-space volume of 5 mb, in which GCOH revealed 15 odorants. Then, the head-space drawn from the sample was reduced in a series of steps to find the most potent odorants. GCOH of volumes of 2.5 and 1.25 mb indicated only seven and five odorants, respectively (Table 16.5) after reduction to 0.6 mb, only methane-thiol, (Z)-3-hexenol and an unknown compound were the most potent, highly volatile odorants of parsley [31]. 

EH s that are often encountered in sediment pore waters. Cores from Mono ake (not shown) had extremely alkaline pH s of 9.8 to 10.1. This high a pH definitely has an effect on the bimane reaction. Pore water samples adjusted to pH 8 gave much higher results which were similar to those obtained from the methylene blue and DTNB method (data not shown). Thiosulfate and sulfite were present in micromolar quantities in cores from all habitats. Thiosulfate was highest in the salt pond cores where it occasionally was more abundant than sulfide. While methane thiol, glutathione, and other organic thiols can be detected by the bimane method, they were not abundant (< 10 mM) in the core samples we chose to analyze. 

Sprensen, J. (1988) Dimethylsulfide and methane thiol in sediment porewater of a Danish estuary. Biogeochemistry 6, 201-210. 

Fig. 4.14. The Chugaev reaction for the dehydration of alcohols. (The decomposition of dithiocarbonic acid methylester—here given in brackets—to form carbon oxy-sulfide and methane thiol is outlined in Section 8.1 near Figure 8.4.)...

Alkyl sulfides and thiols. Some alkyl thiols and sulfides, notably those from commonly ingested Allium sativum (garlic) and Allium cepa (onion) (Alliaceae), are variously bioactive as odorants and antimicrobials. Propanethial S-oxide (CH3-CH2-CH=S=0) is a lachrymatory irritant principle of onion. Allicin (S-oxodiallydisulfide CH2=CH—CH2-SO-S-CH2— CH=CH2), diallyldisulfide (CH2=CH-CH2-S-S-CH2-CH=CH2) and diallylsulfide (CH2=CH—CH2—S—CH2-CH=CH2) are major odorants of garlic that are reactive and irritant because of the allyl groups. Dimethyl disulfide (CH3—S—S-CH3), dipropyl disulfide (CH3-CH2-CH2-S-S-CH2-CH2-CH3), methyl allyl disulfide (CH3-S-S-CH2-CH=CH2) and propane-1-thiol (CH3-CH2—CH2—SH) are further Allium odorants. Methane thiol (methyl mercaptan CH3—SH) is a widespread plant volatile and notably derives from anaerobic bacterial degradation of cysteine as in human flatus and bad mouth odour. The aliphatic disulfides allicin and ajoene inhibit proinflammatory expression of iNOS. 

Methyl mercaptan (= Methane thiol) (alkyl thiol)... 

Methane thiol oxidizes at a convenient rate at 200—275 °C, the reaction being mildly autocatalytic and accompanied by a pressure decrease [107]. The rate is enhanced by increased oxygen concentration, but retarded by excess thiol. The main products include sulphur dioxide, carbon monoxide, formaldehyde, acetaldehyde and methane but no hydrogen sulphide, carbonyl sulphide or free sulphur. Unless excess oxygen is present, these products do not account for all the sulphur consumed, and Cullis and Roselaar [107] attributed this to formation of dimethyl disulphide although later work [108] has shown that this explanation was unlikely. 

Mixtures of dimethyl sulphide and oxygen explode with a blue flash at 210 °C [109]. Sulphur is deposited, and other products include sulphur dioxide, carbon monoxide, carbon dioxide, methane and methane thiol but methanol and dimethyl disulphide were not found. 

The combustion of dimethyl disulphide was studied at 240 °C. The reaction is autocatalytic, the principal products being sulphur dioxide, methanol and carbon monoxide with smaller amounts of formaldehyde, methane thiol and an acid [111]. 

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