Hydrocarbons sulfides, oxidation

In general, peroxomonosulfates have fewer uses in organic chemistry than peroxodisulfates. However, the triple salt is used for oxidizing ketones (qv) to dioxiranes (7) (71,72), which in turn are useful oxidants in organic chemistry. Acetone in water is oxidized by triple salt to dimethyldioxirane, which in turn oxidizes alkenes to epoxides, polycycHc aromatic hydrocarbons to oxides and diones, amines to nitro compounds, sulfides to sulfoxides, phosphines to phosphine oxides, and alkanes to alcohols or carbonyl compounds. 

In the biotechnological arena, a process for removing H2S and mercaptans from a hydrocarbon stream, such as a LPG, was disclosed [171]. Sulfide oxidizing microorganisms, such as those from the genera Thiobacillus and Thiomicrospira, are employed to convert H2S to sulfur and mercaptans to disulfides. First a weakly basic stream, (e.g., a sodium bicarbonate solution) is used to extract the sulfur molecules from the hydrocarbon stream using an ordinary extraction column. The extracted sulfur molecules are then... 

During the chain oxidation of hydrocarbons, sulfides and disulfides terminate chains by reacting with peroxyl radicals [40,42,44], which, as opposed to phenols, are weak inhibitors (see Table 17.6). The mechanism and stoichiometry of the termination reaction by sulfides remain yet unclear. Since sulfenic acid is an efficient scavenger of free radicals, the oxidation of tetralin in the presence of dialkylsulfoxide occurs only if the initiation rate v > vimin is proportional to the concentration of sulfoxide [5], so that the rate of oxidation is... 

Nitrites Nitrobenzene Nitroethane Nitrogen trichloride Organic nitrites in contact with ammonium salts, cyanides Nitric acid, nitrous oxide, silver perchlorate Hydroxides, hydrocarbons, metal oxides Ammonia, As, hydrogen sulfide, nitrogen dioxide, organic matter, ozone, phosphine, phosphorus, KCN, KOH, Se, dibutyl ether... 

Aryl and alkyl hydroxylations, epoxide formation, oxidative dealkylation of heteroatoms, reduction, dehalogenation, desulfuration, deamination, aryl N-oxygenation, oxidation of sulfur Oxidation of nucleophilic nitrogen and sulfur, oxidative desulfurization Oxidation of aromatic hydrocarbons, phenols, amines, and sulfides oxidative dealkylation, reduction of N-oxides Alcohol oxidation reduction of ketones Oxidative deamination... 

Thiazolyl sulfamic acids, rearrangement of sulfonic acid, 70 rearrangement to sulfonic acid, 75 by sulfonation, 75 2-Thiazolyl sulfenyl chloride, transformation to, thiazolyl disulfides. 412 2-Thiazolyl sulfide, in hydrocarbon synthesis, 406 oxidation of, with m-chloroperbenzoic acid, 415 with CrOj, 415 with Hj02,405,415 with KMn04,415 physical properties, infrared, 405 NMR, 404 pKa, 404 ultraviolet, 404 preparation of, from 2-halothiazoles and 5-Thiazolyl sulfides, bis-5-thiazolyl sulfide, oxidation of, 415 general, 418 5-(2-hydroxythiazolyl)phenyl sulfide case, 418 physical properties, 418 preparation of, 417-418 table of compounds, 493-496 uses of. 442 2-Thiazolyl sulfinic acid, decomposition of, 413 preparation of, from 2-acetamidothiazole sulfonyl chloride, 413 from A-4-thiazoline-2-thione and H, 0, 393,413 table of compounds, 472-473 5-Thiazolyl sulfinic add, preparation of,... 

Cziczo DJ, Thomson DS, Murphy DM (2001) Ablation, flux, and atmospheric implications of meteors inferred from stratospheric aerosol. Science 291 1772-1775 Dachs J, Eisemeich SJ (2000) Adsorption onto aerosol soot carbon dominates gas-particle partitioning of polycyclic aromatic hydrocarbons. Environ Sci Technol 34 3690-3697 Dalleska NF, Colussi AJ, Hyldahl AM, Hoffmaim MR (2000) Rates and mechanism of carbonyl sulfide oxidation by peroxides in concentrated sulfuric acid. J Phys Chem A 104 10794-10796 D Almeida GA, Schitz L (1983) Number, mass, and volume distributions of mineral aerosol and soils of the Sahara. J Clim Appl Meteorol 22 233-243... 

Thermogravimetric and Differential Thermal Analysis has been performed on Cat D. The TG and DTA profiles in Fig 2 show three different steps. The first one is the evaporation of hydrocarbons up to 200 °C with a moderate endotherm. The second step is the oxidation reaction of metal sulfides to oxides (most of the Mo sulfide, and part of the Co sulfide), starting around 200-250 °C. The third step around 350-450 °C is strongly exothermic, due to carbon burn-off as well as the remaining of sulfides oxidation. The carbon bum-off reaction finishes around 500 °C in this experiment performed on a dynamic mode at the heating-up rate of 5 °C/min. 

Several hundred sets of data for hydrocarbons on Nuxit-al charcoal obtained by Szepesy and Hies (Valenzuela and Myers, 1989) can be described well by this equation. Because of its simplicity in form and its correct behaviour at low and high pressures, the Toth equation is recommended as the first choice of isotherm equation for fitting data of many adsorbates such as hydrocarbons, carbon oxides, hydrogen sulfide, alcohols on activated carbon as well as zeolites. Sips equation presented in the last section is also recommended but when the behaviour in the Henry law region is needed, the Toth equation is the better choice. 

The basic flow sheet for the flotation-concentration of nonsulfide minerals is essentially the same as that for treating sulfides but the family of reagents used is different. The reagents utilized for nonsulfide mineral concentrations by flotation are usually fatty acids or their salts (RCOOH, RCOOM), sulfonates (RSO M), sulfates (RSO M), where M is usually Na or K, and R represents a linear, branched, or cycHc hydrocarbon chain and amines [R2N(R)3]A where R and R are hydrocarbon chains and A is an anion such as Cl or Br . Collectors for most nonsulfides can be selected on the basis of their isoelectric points. Thus at pH > pH p cationic surfactants are suitable collectors whereas at lower pH values anion-type collectors are selected as illustrated in Figure 10 (28). Figure 13 shows an iron ore flotation flow sheet as a representative of high volume oxide flotation practice. 

Isoprene [78-79-5] (2-methyl-1,3-butadiene) is a colorless, volatile Hquid that is soluble in most hydrocarbons but is practically insoluble in water. Isoprene forms binary azeotropes with water, methanol, methylamine, acetonitrile, methyl formate, bromoethane, ethyl alcohol, methyl sulfide, acetone, propylene oxide, ethyl formate, isopropyl nitrate, methyla1 (dimethoxymethane), ethyl ether, and / -pentane. Ternary azeotropes form with water—acetone, water—acetonitrile, and methyl formate—ethyl bromide (8). Typical properties of isoprene are Hsted in Table 1. 

Zinc oxide is effective in removing H2S, mercaptans, and, to some extent, chlorides. At temperatures above 350 °C, mercaptans decompose to hydrocarbons and H2S which then reacts with the 2inc oxide to form 2inc sulfide. 

Sulfur reacts with alkanes to either dehydrate (eq. 1), oxidize, forming carbon disulfide and hydrogen sulfide (eq. 2), or cyclize, forming thiophenes (eq. 3). The products of alkane sulfurization depend on the temperature, the time at the temperature, and the stmcture of the hydrocarbon (1). 

A derivative of the Claus process is the Recycle Selectox process, developed by Parsons and Unocal and Hcensed through UOP. Once-Thm Selectox is suitable for very lean acid gas streams (1—5 mol % hydrogen sulfide), which cannot be effectively processed in a Claus unit. As shown in Figure 9, the process is similar to a standard Claus plant, except that the thermal combustor and waste heat boiler have been replaced with a catalytic reactor. The Selectox catalyst promotes the selective oxidation of hydrogen sulfide to sulfur dioxide, ie, hydrocarbons in the feed are not oxidized. These plants typically employ two Claus catalytic stages downstream of the Selectox reactor, to achieve an overall sulfur recovery of 90—95%. 

Finally, selective separation and dewatering of one suspended substance in a slurry containing different minerals or precipitates is possible by selectively adsorbing a magnetic material (usually hydrophobic) onto a soHd that is also naturally or chemically conditioned to a hydrophobic state. This process (Murex) was used on both sulfide ores and some oxides (145). More recently, hydrocarbon-based ferrofluids were tested and shown to selectively adsorb on coal from slurries of coal and mineral matter, allowing magnetic recovery (147). Copper and zinc sulfides were similarly recoverable as a dewatered product from waste-rock slurries (148). 

Absorption of pollutant gases is accomplished by using a selective liquid in a wet scrubber, packed tower, or bubble tower. Pollutant gases commonly controlled by absorption include sulfur dioxide, hydrogen sulfide, hydrogen chloride, chlorine, ammonia, oxides of nitrogen, and low-boiling hydrocarbons. 

The gaseous component typically contains hydrocarbons, hydrogen sulfide, ammonia, mercaptans, solvents, and other constituents, and is either discharged directly to the atmosphere or is combusted in a flare. The major air emissions from blowdown systems are hydrocarbons in the case of direct discharge to the atmosphere and sulfur oxides when flared. 

Since aluminum is not attacked by hydrogen sulfide (HjS) solutions, it is used widely as a material in refineries for the handling of hydrocarbons made from sour crudes. In the strongly oxidizing conditions of manufacturing hydrogen peroxide, aluminum is one of the few materials that does not undergo decomposition. 

This process includes two main sections the burner section with a reaction chamber that does not have a catalyst, and a Claus reactor section. In the burner section, part of the feed containing hydrogen sulfide and some hydrocarbons is burned with a limited amount of air. The two main reactions that occur in this section are the complete oxidation of part of the hydrogen sulfide (feed) to sulfur dioxide and water and the partial oxidation of another part of the hydrogen sulfide to sulfur. The two reactions are exothermic ... 

Due to the presence of hydrocarbons in the gas feed to the burner section, some undesirable reactions occur, such as the formation of carbon disulfide (CS2) and carbonyl sulfide (COS). A good catalyst has a high activity toward H2S conversion to sulfur and a reconversion of COS and CS2 to sulfur and carbon oxides. Mercaptans in the acid gas feed results in an increase in the air demand. For example, approximately 5-13% increase in the air required is anticipated if about 2 mol% mercaptans are present. The increase in the air requirement is essentially a function of the type of mercaptans present. The oxidation of mercaptans could be represented as ... 

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