Mercaptans odor caused

Properties Cryst. or pellets, si, mercaptan odor insol. in water m.w. 261.34 dens. 1.3 mg/m m.p. 90-95 C flash pt. (PMOC) 165 C Toxicology LD50 (oral, rat) 2600 mg/kg, (skin, rabbit) > 5010 mg/kg mod. toxic by ing. irritating to skin and eyes may cause allergic skin reaction questionable carcinogen experimental reproductive effects Precaution Fire produces toxic fumes avoid contact with acids... 

Term used for natural gas or a gasoline contaminated with odor-causing sulfur compounds. In natural gas, the contaminant is usually hydrogen sulfide (HjS) and can be fatal in high concentrations in gasoline, mercaptans are usually the source. 

The so-called boeckser is caused by the smell of hydrogen sulfide. The very unpleasant, rotten and yeasty boeckser (= mercaptan) odor is most objectionable and fingers for a long time. It is due to ethylthiol, which can be removed by activated charcoal. The volatile sulfur com-... 

The generation of odor-eausing materials sueh as aldehyde, mercaptan, amine, ammonia, and ethylene is unavoidable when fruits and vegetables or fish are to be transported. Thus for freshness preservation, removal of these odors is also important. Various sheets in which a deodorant based on adsorption such as activated charcoal, zeolite or cristobalite have been mixed and tested [6, 7]. Additionally, deodorants, such as Fe-phthalocya-nine complex, based on decomposition of odor-causing compounds, are also available [6, 7]. 

Sights, odors, or sounds that could cause pubbc concern or inquiries, such as smoke and odors below hazardous levels—for example, mercaptans or amines... 

Water and sulfur compounds are the principal non-hydrocarbon impurities present in light ends which frequently require removal. The sulfur compounds of concern are concerned with here are hydrogen sulfide and mercaptans, both of which have to be removed almost quantitatively from any light ends cut which is going to be marketed. There are two reasons for this First, they have an objectionable odor, even in minute concentrations. Second, they may cause corrosion either by themselves or through their combustion products. 

The use of high-sulfur-content fuels could enhance undesirable carbon-forming tendencies in the engine combustion chamber as well as result in higher amounts of corrosive sulfur oxides in the combustion gases. Mercaptans (a type of sulfur compound) cause odor problems and can attack some fuel system elastomers. Both the concentration of total sulfur compounds as well as the concentration of mercaptan sulfur compounds arc controlled in... 

List any sights, odors or sounds that might come from your facility and cause public concern or inquiries (e.g., smoke, large relief valves, odors below hazardous levels such as mercaptans or amines, etc.)... 

A drop in media pH may result in odor problems caused by the system s inability to treat organic sulfides and mercaptan compounds. 

The odor of the mercaptan is extremely disagreeable, and the substance in high concentration causes headache. An effective hood is absolutely essential. 

Volatile methanethiol from biogenic sources is released to the atmosphere in coastal and ocean upwelling areas.1 Methanethiol and volatile liquid ethanethiol (bp, 35°C) are intermediates in pesticide synthesis and odorants placed in lines and tanks containing natural gas, propane, and butane to warn of leaks. Information about their toxicities to humans is lacking, although these compounds and 1-propanethiol should be considered dangerously toxic, especially by inhalation. Also known as amyl mercaptan, 1-pentanethiol (bp, 124°C) is an allergen and weak sensitizer that causes contact dermatitis. 

The simplest of the aryl thiols is benzenethiol, phenyl mercaptan (bp, 168°C). It has a severely repulsive odor. Inhalation causes headache and dizziness, and skin exposure results in severe contact dermatitis. 

The modification of silica gel with diethanolamine (DEA) resulted in a stable alkaline filter, capable to collect H2S, COS, CS2, S02, C02 and H20 from contaminated air.56 The presence of odorous mercaptanes and organic sulphides may be selectively determined, as these compounds do not react with the DEA and therefore are not collected on the filter. By means of this scrubber an automatic survey system has been developed allowing the detection and determination of the nature of odour nuisance, caused by industrial emissions of volatile organic sulphur compounds, up to the ppb-level. The system consists of two continuous, highly sensitive and fast responding sulphur analyzers. One of the detectors is equipped with an SO, scrubber and measures the total amount of non-S02 sulphur compounds. The other detects the organic S-compounds, using the amine-silica filter. 

Odor is a sensation associated with smell, which can be hard to quantify. The same quantities of different materials cause different odor intensities. The unit of odor intensity (W) is based on the odor of tertiary butyl mercaptan or TBM (W = 1.0). Using that reference, H2S, for example, has an odor intensity of W = 0.08, or 8% of TBM. Most odorant substances contain sulfur. Table 3.31 lists a number of odorant substances and their relative odor intensities (W). 

The primary disadvantages of polymercaptans over other fast-reacting curing systems are (1) skin irritation caused by aromatic mercaptans (aliphatic mercaptans are less der-matitic than common polyamides) and (2) an objectionable sulfur odor, especially when the vapor pressure of the mercaptan is relatively high. 

PROP Compounds containing the -SH group bound to carbon. Also called thiols. SAFETY PROFILE Generally they have a very offensive odor that may cause nausea and headache. High concentrations of vapor can produce unconsciousness with cyanosis, cold extremities, and rapid pulse. A common air contaminant. Dangerous when heated to decomposition they almost always emit highly toxic fumes of SO. They may react with water, steam, or acids to produce toxic and flammable vapors. Aliphatic mercaptans are flammable. They can react violently with powerful oxidizers such as Ca(OCl)2. 

Air pollution problems center around control of the formation and discharge of reduced sulfur compounds, which cause severe odor problems (Table 15.11), and the loss of particulates. Hydrogen sulfide and methyl mercaptan are more readily lost from aqueous solution because of their low-boiling points and high Henry s law constants. Hydrogen sulfide, however, is relatively easily dispersed in air, because of its more similar density, whereas the others tend to hug the ground and settle in depressions. 

Sweetening is an efficient catalytic process for the removal of sulfur present as mercaptans in light oils. Even when present in very small quantities, mercaptans cause foul odor, deterioration of additives in finished products and are corrosive. They are oxidized to innocuous disulfides by air under caustic condition and in the presence of cobalt phtalocyanine catalyst [1]. In industrial process, the use of caustic soda solution leads nevertheless to environmental problems in the refinery. 

Refining treatment includes among its objects the removal of such undesirable products as hydrogen sulfide, mercaptan sulfur, and free or corrosive sulfur. Hydrogen sulfide and mercaptans cause objectionable odors, and both are corrosive. The presence of such compounds can be determined by the Doctor test (ASTM D-484, ASTM D-4952, IP 30). The Doctor test (which is pertinent for petroleum product specifications ASTM D-235) ensures that the concentration of these compounds is insufficient to cause such problems in normal use. In the test, the sample is shaken with sodium plumbite solution, a small quantity of sulfur is added, and the mixture is shaken again. The presence of mercaptans, hydrogen sulfide, or both is indicated by discoloration of the sulfur floating at the oil-water interface or by discoloration of either of the phases. 

Why does eating asparagus produce bad-smelling urine Asparagus contains the amino acid methionine, which is metabolized in the body to produce methyl mercaptan. The peculiar odor of urine produced after consuming asparagus is caused by the methyl mercaptan excreted from the body in urine. 

Thioglycolic acid (mercaptoacetic acid [CAS 68-11-1]) Skin or eye contact with concentrated acid causes severe bums. Vapors irritating to eyes and respiratory tract. 1 ppm, S Coloriess liquid. Unpleasant mercaptan-llke odor. Vapor pressure is 10 mm Hg at 18°C (64°F). Found In some coldwave and depllatoiy formulations. 

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