Sulfides hydrogen

Hydrogen Sulfide, Sodium Sulfide, and Other Inorganic Salts 

At lower temperatures oxygenated compounds may be isolated thus the treatment of diethyl acetylsuccinate (2) with hydrogen sulfide yields the thiophene derivative (3).6 

A more complex example of sulfur insertion is the formation of a bithiopyran (4) from an acyclic precursor (5) when treated with a mixture of hydrogen sulfide and hydrogen chloride.7 

Sometimes, hydrogen sulfide converts an oxygen-containing heterocycle into a sulfur-containing one, and as furans and polycyclic furans are very common in nature such reactions may be the origin of the polycyclic thiophenes mentioned above. A typical example is the formation of the isothiazolin-3-thione (6) from the isoxazolin-3-thione (7) on treatment with hydrogen sulfide and hydrogen bromide.8 

Hydrogen sulfide is typically found in well water that is devoid of oxygen. This compound easily oxidizes and releases elemental sulfur, which is very sticky and results in irreversible fouling of RO membranes. Metal sulfides can also form, which can precipitate. Deposits can be sooty-black or a pasty-gray.8 Fouling with elemental sulfur or metallic sulfides will cause a decrease if flux and an increase in salt passage. 

The following equations show the dependence of the amount of hydrogen sulfide in solution on the pH of the system  

Others recommend treatment to remove the compound. Hydrogen sulfide can be removed or reduced from RO feed water using some iron filters (such as manganese greensand and Filox, see Chapter 8.1.5) or a complicated combination of oxidation, coagulation and filtration, sulfite addition, and rechlorination.9 

Because hydrogen sulfide is a gas, it is not rejected by an RO membrane. For systems that do not remove the compound prior to the RO membranes, hydrogen sulfide will be present in the permeate. Exposure to air on the permeate side of the membrane, such 

Hydrogen sulfide is a weak, diprotic acid (i.e., it undergoes two acid reactions). The ionization reactions are as follows  

The subscript (aq) indicates that the reaction takes place in the aqueous (water-rich) phase. 

It is the H+ ion that makes the solution acidic. Hydrogen sulfide is diprotic because it has two reactions that both form the hydrogen ion. Furthermore, when hydrogen sulfide is dissolved in water it exists as three species - the molecular form (H2S) and the two ionic forms the bisulfide ion (HS ) and the sulfide ion (S2 ). 

The measure of how far these reactions proceed is the equilibrium ratios. For our purposes, these ratios are as follows  

Hydrogen sulfide is present in large quantities in crude oil and especially in natural gas (it is proces.sed to elemental sulfur see Section 1.6.1.2.2). In addition small quantities are dissolved in mineral springs and it is formed as a byproduct in a large number of chemical reactions. 

Industrially hydrogen sulfide is mainly manufactured from pure sulfur and pure hydrogen at ca. 350°C in the presence of catalysts, such as cobalt molybdenum oxide on Y-AI2O3. 

Hydrogen sulfide is a gas typically found in well water that is devoid of oxygen. It is the result of sulfate-reducing bacteria oxidizing organic matter, which releases hydrogen sulfide gas. Hydrogen sulfide is a weak acid whose speciation depends on pH as follows  

The chemistry of sulfur dioxide is not fully rmderstood, but does involve several intermediates the mechanisms are not as clean as the equations imply. For example, hydrogen sulfide is chemically oxidized by dissolved oxygen  

this reaction passes through several intermediates of different oxidation states, including sulfite (SO ), which can further react with hydrogen sulfide ion (HS ) to yield thiosulfate. The thiosulfate can be oxidized to yield sulfate via production of tetrathionate, In the presence of 

Elemental sulfur can react with sulfite and sulfide to yield thiosulfate and polysulfides (which are unstable in oxic conditions and decomposes to elemental sulfur and thiosulfate), respectively  

Hydrogen sulfide can also react with metal salts, such as iron and manganese which are also present in most well water sources. 

Synonyms Sulfuretted hydrogen, hydrogen sulphide, hydrosulfuric acid 

Critical temperature Critical pressure Specific heat of the liquid at 60°F (15.5°C) 

Hydrogen sulfide is a colorless, flammable, poisonous gas or liquid, with an offensive odor and irritant properties. Hydrogen sulfide is slightly heavier than air, and the liquid phase is somewhat less dense than water. Combustion of hydrogen sulfide in air forms sulfur dioxide and water. 

Hydrogen sulfide can act as a reducing agent. It reacts readily with all metals in the electromotive series down to and including silver. However, in some cases the resultant sulfide coating prevents further reaction. Hydrogen sulfide is somewhat soluble in water, alcohol, petroleum solvents, and crude petroleum. 

In commerce, hydrogen sulfide is transported as a flammable liquefied compressed gas. It is transported and stored under its own vapor pressure in authorized cylinders, tank cars, and cargo tanks (tank trucks). It is used in research, in metals refining, and in the production of a number of basic and specialty chemicals. 

Banerjee BD, Dwivedi S, Singh S Acute hydrogen selenide gas poisoning admissions in one of the hospitals in Delhi, India case report. Hum Exp Toxicol 16 276-8, 1997 

Levy LS, Shackleton S, Smillie MV Criteria Document for Hydrogen Selenide Occupational Exposure Limits, pp 1-58, 1992 

Sources. By-product of many industrial processes around oil wells and in areas where petroleum products are processed, stored, or used decay of organic matter occurs naturally in coal, natural gas, oil, volcanic gases, and sulfur springs. 

Toxicology. Hydrogen sulfide is an irritant of the eyes and respiratory tract at low concentrations at higher levels, it causes respiratory paralysis with consequent asphyxia and is rapidly fatal. 

The sequelae of acute poisoning appear to be quite variable and depend on duration of exposure as well as level of exposure. Patients who have been unconscious in high levels of hydrogen sulfide atmosphere for longer than 5 min may have persistent neurological and neuropsychological impairment years after exposure as a result of hydrogen sulfide-induced hypoxia.  

CHEMICAL NAME = hydrogen sulfide CAS NUMBER = 7783-06-4 MOLECULAR FORMULA = H2S MOLAR MASS = 34.1 g/mol COMPOSITION = H(5.9°/o) S(94.1°/o) 

Hydrogen sulfide was known to exist in water in the 15th century and was called sulfur water or sulfur vapors. Alchemists referred to H2S as aer hepaticus (hepatic air). Early chemists called it sulfuretted hydrogen, a term still used today. Carl Wilhelm Scheele (1742-1786) was the first chemist to prepare and describe hydrogen sulfide he considered it a combination of sulfur, phlogiston, and heat. Claude Louis Berthollet (1748-1822) determined the composition of H2S in 1789 and noted its acidic nature. 

Hydrogen sulfide is produced during anaerobic respiration (fermentation). Anaerobic respiration enables organisms, primarily bacteria and other microbes, to meet their energy needs using sulfate, elemental sulfur, and sulfur compounds as electron acceptors instead of oxygen. 

A simplified reaction representing anaerobic respiration is S042 + 2(CH20)(s) — H2S 

2HC032. The hydrogen sulfide produced in this reaction can be oxidized back to sulfate or 

LABORATORY CHEMICAL SAFETY SUMMARY HYDROGEN SULFIDE  

Substance Hydrogen sulfide (Hydrosulfuric acid, sulfur hydride) CAS 7783-06-4 

Odor Strong rotten egg odor detectable at 0.001 to 0.1 ppm (mean = 0.0094 ppm) olfactory fatigue occurs quickly at high concentrations 

Major Hazards Moderately toxic gas inhalation of large concentrations can cause unconsciousness, respiratory paralysis, and death highly flammable. 

Flammability and Explosibility Hydrogen sulfide is flammable in air in the range of 4.3 to 45.5% (NFPA rating = 4). Combustion products (sulfur oxides) are also toxic by inhalation. In the event of a hydrogen sulfide fire, stop the flow of gas if possible without risk of harmful exposure and let the fire burn itself out. 

The photochemical dynamics of H2S has been studied in its first absorption band between 180 and 260 nm (2) using LIF measurements to determine the quantum state distribution of the SH fragment (169-171), as well as TOF measurements of the velocity distribution of H atom fragment (172). In the former case, the vibrational and rotational distribution of the SH fragment was only measured in the v = 0 level because fewer radicals with v 0 are produced and the LIF technique does not efficiently detect these excited radicals. 

The TOF measurements of the H atom produced in the photodissociation of H2S indicate that a substantial number of HS radicals are produced vibrationally excited at each of the wavelengths studied. Their results are summarized in Table 9. 

The observed vibrational excitation is explained using a predissociation mechanism. It is postulated that the iBj state is excited by direct absorption, and is crossed at two different S-H internuclear distances rSH and r by a 2 repulsive state. 

TABLE 9. Energy Distributions of the HS Fragment Produced in the Photolysis of S3 

Recent calculations by Kulander (173), using model potentials that mimic those suggested by van Veen et al., confirm that the proposed model could be used to explain the observations. Without accurate upper potential surfaces one cannot, however, exactly reproduce the observed vibrational distributions.  

Colorless gas with an offensive odor characteristic of rotten eggs bp, -60.33 C.1 

Explosive limits, 4.3-46% ignition temperature, 260°C. Shut off the gas flow and extinguish fire with water, dry chemical, or carbon dioxide. If possible, cylinders should be removed quickly from an area in which a fire has developed.2 

One gram dissolves in 242 mL of water, 94.3 mL of absolute ethanol, and 48.5 mL of ether at 20°C also soluble in glycerol.1 Aqueous solutions are not stable absorbed oxygen causes formation of elemental sulfur.2 

4-Bromobenzenediazonium Chloride. Interaction with hydrogen sulfide produces a solid product that explodes under water at 0°C.3 

Copper and Oxygen. A 1 2 mixture of hydrogen sulfide and oxygen ignites in the presence of copper powder.4 

Many of these membranes are designed for sweetening of natural gas and therefore exhibit high permeabilities for H2S and CO2 with large selectivity relative to methane [34], A large number of membranes demonstrate selectivity towards H2S over CO2, attributed to the higher condensability of H2S (for critical temperature see Table 11.2) within the membrane, compared to CO2. Similar to SO2, H2S has been reported to plasticize or swell polymeric membranes [35]. 

However, nitrogen is not the only nutritional factor that influences H2S evolution in grape musts as evidenced by Sea et al. (1998) who reported poor correlations between H2S and must nitrogen concentrations. Metabolic depletion of OAS and OAH could be the result of a lack of pantothenic acid, a vitamin required for the synthesis of coenzyme A (GoA), which is necessary for formation of these precursors (Fig. 1.12). In agreement, pantothenic acid deficiency is known to increase H2S pro- 

Wang et al. (2003) reported that a complicated relationship exists between nitrogen and pantothenic acid that affects H2S production (Fig. 8.2). Here, HgS production decreased with an increase of nitrogen but only in the presence of 250pg/L pantothenic acid. If pantothenic acid was present at 50[Xg/L or less, the amount of H2S evolved actually increased with an increase in available nitrogen. This observation had not been reported previously and casts doubt on the belief that addition of nitrogen to grape musts will always reduce H2S problems (Tamayo et al., 1999). 

Other factors are also known to impact H2S in wine. For instance, Karagiannis and Lanaridis (1999) studied addition of sulfite, must turbidity, yeast strain, fermentation temperature, and lees contact on H2S formation. Among other findings, the authors noted that more H2S was present if the wine was left on lees for 2 months. Although elemental sulfur used in the vineyard can also be a source of H2S (Acree et al., 1972 Eschenbruch, 1974), very high concentrations on the treated grapes may be required (Thomas et al., 1993). 

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ST HYDROGEN SULFIDE 190-298 2.1163E402 -6.799BE403 9.0769E-02 -3 6797E401 -3 8744E-05... 

HYDROGEN SULFIDE 2.2948E 01 7.7244E 02 I.8856E-02 S.2914E-01... 

Fixed-bed noncatalytic reactors. Fixed-bed reactors can be used to react a gas and a solid. For example, hydrogen sulfide can be removed from fuel gases by reaction with ferric oxide ... 

For example, hydrogen sulfide and carbon dioxide can be removed from natural gas by reaction with monoethanolamine in an absorber according to the following reactions ... 

These reactions can be reversed in a distillation column. This releases the hydrogen sulfide and carbon dioxide for further processing. The monoethanolamine can then be recycled. 

Sulfur might be present in inorganic forms elemental S, hydrogen sulfide H2S, carbonyl sulfide COS, or positioned within organic molecules as in the following ... 

Finally, there are some limits regarding LPG fuels butadiene content (0.5 wt. % maximum, ISO 7941), the absence of hydrogen sulfide (ISO 8819) and copper strip corrosion (class 1, ISO 6251) which are not usually problems for the refiner. 

Corrosion protection is indispensable, especially concerning certain vulnerable parts of the aircraft such as the combustion chamber and turbine. The potential hazards are linked to the presence of sulfur in various forms mercaptans, hydrogen sulfide, free sulfur, and sulfides. 

Sometimes analyses are required for particular compounds such as sulfur, chlorine and lead, or for specific components such as mercaptans, hydrogen sulfide, ethers and alcohols. 

Sulfur compounds No reaction at sodium plumbite test (NF M 41-006) Pass hydrogen sulfide test (ISO 8819, future NF EN 28819)... 

Crude oils appear as liquids of varying viscosities. Their color can range from green (crude from Moonie, Australia) to dark brown (crude from Ghawar, Saudi Arabia). They can have an odor of hydrogen sulfide, turpentine or simply hydrocarbon. 

Hydrogen chloride released dissolves in water during condensation in the crude oil distillation column overhead or in the condenser, which cause corrosion of materials at these locations. The action of hydrochloric acid is favored and accelerated by the presence of hydrogen sulfide which results in the decomposition of sulfur-containing hydrocarbons this forces the refiner to inject a basic material like ammonia at the point where water condenses in the atmospheric distillation column. 

Table 10.14 provides some essential information concerning the production of hydrogen by partial oxidation of a VR. By-products are carbon dioxide and hydrogen sulfide. 

The conversion products, other than gas and hydrogen sulfide (H2S), are essentially a gasoline fraction that, after pretreatment, will be converted by catalytic reforming an average quality distillate fraction to be sent to the gas oil pool and an atmospheric residue or vacuum distillate and vacuum residue whose properties and impurity levels (S, N, Conr. 

Acid gases are mainly hydrogen sulfide (H2S) originating essentially from hydrotreating units off-gas. Smaller quantities are also produced in thermal and catalytic cracking units. 

Hydrogen sulfide concentrates in refinery off gases. Before being used as fuel gas, the gas undergoes an amine (MEA, DEA, etc.) washing step in order to extract the H2S. 

The concentrated hydrogen sulfide gas is then sent to the sulfur production unit (Claus process). 

Purification of refinery gases by elimination of hydrogen sulfide as well as Claus units for sulfur recovery began to make their appearance. 

Organic compounds containing sulfur are very important. Calcium sulfur, ammonium sulfate, carbon disulfide, sulfur dioxide, and hydrogen sulfide are but a few of the many important compounds of sulfur. 

Carbon disulfide, hydrogen sulfide, and sulfur dioxide should be handled carefully. Hydrogen sulfide in small concentrations can be metabolized, but in higher concentrations it quickly can cause death by respiratory paralysis. 

Pure silver has a brilliant white metallic luster. It is a little harder than gold and is very ductile and malleable, being exceeded only by gold and perhaps palladium. Pure silver has the highest electrical and thermal conductivity of all metals, and possesses the lowest contact resistance. It is stable in pure air and water, but tarnishes when exposed to ozone, hydrogen sulfide, or air containing sulfur. The alloys of silver are important. 

Similar to oxonium ions, our studies of sulfonium ions also showed protosolvolytic activation in superacids to give sulfur superelectrophiles. The parent sulfonium ion (HjS ), for example, gives H4S (diprotonated hydrogen sulfide) in superacids. 

The problem of the synthesis of highly substituted olefins from ketones according to this principle was solved by D.H.R. Barton. The ketones are first connected to azines by hydrazine and secondly treated with hydrogen sulfide to yield 1,3,4-thiadiazolidines. In this heterocycle the substituents of the prospective olefin are too far from each other to produce problems. Mild oxidation of the hydrazine nitrogens produces d -l,3,4-thiadiazolines. The decisive step of carbon-carbon bond formation is achieved in a thermal reaction a nitrogen molecule is cleaved off and the biradical formed recombines immediately since its two reactive centers are hold together by the sulfur atom. The thiirane (episulfide) can be finally desulfurized by phosphines or phosphites, and the desired olefin is formed. With very large substituents the 1,3,4-thiadiazolidines do not form with hydrazine. In such cases, however, direct thiadiazoline formation from thiones and diazo compounds is often possible, or a thermal reaction between alkylideneazinophosphoranes and thiones may be successful (D.H.R. Barton, 1972, 1974, 1975). 

Chrysean (10), prepared by bubbling hydrogen sulfide through a sodium cyanide solution, was among the first described thiazoles (53-57). Other 5-aminothiazoles are also most easily prepared bv hetero-cyclization (see Chapter 11. Section II.5.A). 

Electron-deficient alkenes add stereospecifically to 4-hydroxy-THISs with formation of endo-cycloadducts. Only with methylvinyl-ketone considerable amounts of the exo isomer are produced (Scheme 8) (16). The adducts (6) may extrude hydrogen sulfide on heating with methoxide producing 2-pyridones. The base is unnecessary with fumaronitrile adducts. The alternative elimination of isocyanate Or sulfur may be controlled using 7 as the dipolarenOphile. The cycloaddition produces two products, 8a (R = H, R = COOMe) and 8b (R = COOMe, R =H) (Scheme 9) (17). Pyrolysis of 8b leads to extrusion of furan and isocyanate to give a thiophene. The alternative S-elimi-nation can be effected by oxidation of the adduct and subsequent pyrolysis. 

Other sulfur compounds such as thiourea, ammonium dithiocarbamate, or hydrogen sulfide also lead to 2-mercaptothiazoles. Thus thiourea has been used in the syntheses of 4,5-dimethyl (369) and 4-aryl-2-mercapto-thiazoles (Table 11-30) (519). The reactions were carried out by condensing the ia -thiocyanatoketones with thiourea in alcohol and water acidified with hydrochloric acid. By this procedure, 4-aryl-2-mercaptothiazoles were obtained in yields of 40 to 80% with bis-(4-aryl-2-thiazolyl) sulfides as by-products (519). These latter products (194) have also been observed as a result of the action of thiourea on 2-chloro-4-arylthiazole under the same experimental conditions. They can be separated from 2-mercaptothiazoles because of their different degrees of solubility in sodium hydroxide solution at 5%. In this medium bis-(4-phenyl-2-thiazolyl)sulfide is... 

MSH (a metal hydrogen sulfide a source of the nucleophilic anion HS )... 

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