Volatile alkyl sulfides

Abalos, M., Prieto, X., and Bayona, J. M., Determination of volatile alkyl sulfides in wastewater by headspace solid-phase microextraction followed by gas chromatography-mass spectrometry,... 

OPEOS (octylphenol ethoxysulphonate) VASs (volatile alkyl sulfides)... 

Factors that affect the process are fiber material, extraction time, and temperature. Thus, selecting the appropriate SPME fiber is one of the most important factors to consider. For example, the best fiber for volatile compounds or analytes present at low concentrations is PDMS fiber. Volatile alkyl sulfides in wastewater were determined by HS-SPME [20]. In this experiment the effect of the temperature was evaluated. 

Dimethylsulfide is an alkyl sulfide or thioether. It is a volatile liquid (bp, 38°C) that is moderately toxic by ingestion. Thiophene is the most common cyclic sulfide. It is a heat-stable liquid (bp, 84°C) with a solvent action much like that of benzene. It is used in the manufacture of pharmaceuticals and dyes, as well as resins that also contain phenol or formaldehyde. Its saturated analog is tetrahydrothiophene, or thiophane. 

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. 

Alkyl sulfides or thioethers contain the C—S—C functional group. The lightest of these compounds is dimethyl sulfide, a volatile liquid (bp 38°C) that is mod tely toxic by ingestion. It is now known to be a major source of gaseous sulfur entering... 

The alkyl chain distribution of the base alcohol in alcohol sulfates is easily determined by gas chromatography. However, alcohol sulfates and alcohol ether sulfates are not volatile and require a previous hydrolysis to yield the free alcohol. The extracted free alcohol can be injected directly [306] or converted to its trimethylsilyl derivative before injection [307]. Alternatively, the alcohol sulfate can be decomposed by hydroiodic acid to yield the alkyl iodides of the starting alcohols [308]. A preferred method forms the alkyl iodides after hydrolysis of the alcohol sulfate which are analyzed after further extraction of the free alcohol, thus avoiding the formation of hydrogen sulfide. This latter method is commonly used to determine the alkyl chain distribution of alcohol ether sulfates. 

A number of volatile aliphatic compounds that contain nitrogen or sulfur atoms are important aroma constituents. Alkyl thiols, dialkyl sulfides and disulfides, and alkyl thiocyanates belong to this group. They occur widely in foods and spices and determine the odor of, for example, onions, garlic, and mustard. Because of their potent smell, they are used in high dilution and are often produced only in small quantities. The same is true for the following ... 

The feed and recycled iso-butane pass to reactor 1 (Fig. 6.18). The product from the reactor passes to separator 2, where this is separated to acid and the product. The product is then distilled into an alkylate (desired product) fraction and the volatile product containing the hydrofluoric acid vapor and the rest of the isobutane. This volatile product passes to the next separation tower 4 where this is separated into propane with the hydrogen sulfide from the product and the bottom product directed to reactor 1. The propane with the hydrogen sulfide passes to the separation tower 5, the bottom product of which is pure propane. 

Atmosphere. From any soluble or insoluble mercury compound a measurable amount of mercury evaporates. The volatility of the compounds is strongly influenced by their solubility in water, adsorption on surfaces, and the relative humidity of the air. For example, 50 times more mercury is volatilized from the sulfide at 24°C at a relative humidity of air of 100% than at 0% (24). The relative amounts volatilized from other compounds are given in Tables I and II. The alkyl and aryl mercurials are by far the most volatile. 

Various volatile compounds such as skatole, indole, sulfides, and long chain alcohols have been identified in the headspace of saliva samples. These materials increase in both a quantitative and qualitative fashion with varying degrees of periodontitis. Specifically, alkyl pyridines appear to be present in the saliva only in individuals with periodontal disease. The monitoring of these compounds may allow the detection of the early stages of this disease process which effects 60-70% of the population. 

Nitrogen-containing volatiles such as methyl anthranilate (30), methyl N-methyl anthranilate (31), indole (32), 3-methyl indole (= skatole) (33), 2-methoxy-3-iso-butylpyrazine (34), alkyl pyrazines (35), quinoline (36), methyl quinoline (37), pyridines (38), and so on sulfur-containing volatiles such as sulfides and thiophenes (e.g., dimethyl sulfide (39), dimethyl disulfide (40), diallyl disulfide (42), 3,2-dimethylthiophene (43), 4-mercapto-4-methyl pentanone (44), 8-mercapto-/ -men-than-3-one (45), l-/ -menthene-8-thiol (46), 3-mercaptohexanol (47), 5-prenylth-ioesters, thiazols, sulfides of mono- and sesquiterpenes, mint sulfide (48), isomint sulfide (49), etc.) (1, 2, 13, 14). 

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