Rhenium sulfides

Rhenium oxides have been studied as catalyst materials in oxidation reactions of sulfur dioxide to sulfur trioxide, sulfite to sulfate, and nitrite to nitrate. There has been no commercial development in this area. These compounds have also been used as catalysts for reductions, but appear not to have exceptional properties. Rhenium sulfide catalysts have been used for hydrogenations of organic compounds, including benzene and styrene, and for dehydrogenation of alcohols to give aldehydes (qv) and ketones (qv). The significant property of these catalyst systems is that they are not poisoned by sulfur compounds. 

Treatment of the rhenium sulfide chlorides with an excess of chlorine at temperatures above 450°C results in formation of ReCls 140). Reduction between 350 and 500°C gives binary rhenium chalcogenides 139,262). Action of water vapor on rhenium sulfide chlorides at 350-500°C produces oxysulfides 139). 

Rhenium halides, 21 699-700 Rhenium hydrides, 21 700 Rhenium imports, U.S., 21 688t Rhenium oxides, 21 699 Rhenium powder, 21 688, 689, 690, 693 specifications for, 21 694t Rhenium sulfides, 21 699... 

Triple bonds in side chains of aromatics can be reduced to double bonds or completely saturated. The outcome of such reductions depends on the structure of the acetylene and on the method of reduction. If the triple bond is not conjugated with the benzene ring it can be handled in the same way as in aliphatic acetylenes. In addition, electrochemical reduction in a solution of lithium chloride in methylamine has been used for partial reduction to alkenes trans isomers, where applicable) in 40-51% yields (with 2,5-dihydroaromatic alkenes as by-products) [379]. Aromatic acetylenes with triple bonds conjugated with benzene rings can be hydrogenated over Raney nickel to cis olefins [356], or to alkyl aromatics over rhenium sulfide catalyst [54]. Electroreduction in methylamine containing lithium chloride gives 80% yields of alkyl aromatics [379]. 

A similar relationship can be observed with promoted M0S2. Each family of catalysts has its own linear correlation, which cannot be compared to each other directly because of the corrosivity problem. More recently, low-temperature oxygen chemisorption has been claimed to be more reliable, but it also lacks a well-determined stoichiometry (52). Oxygen chemisorption has also been applied to tungsten and rhenium sulfides, as well as promoted molybdenum and tungsten sulfides. In the isotropic class, it has been applied only to ruthenium sulfide, in which case it gives approximately the same result as a BET measurement due to the isotropic nature of this sulfide (41). 

Rhenium pentachloride, 180 Rhenium sulfide, 177 Rhenium trichloride, 182 Rubidium, metallic, 79... 

According to Platonov et al. (309), nickel can be poisoned by H2S, S02, H2SO4, As203, and P206, after which it will direct the decomposition of formic acid preferentially in one of three possible ways above a critical amount of the poison the latter ceased to act selectively and the catalyst was deactivated. In another study (310) Platonov and co-workers demonstrated that over rhenium catalysts, partly poisoned with H2S or AS2O3, methanol was converted to formaldehyde in preference to the complete decomposition which occurred over the unpoisoned catalyst. However, rhenium sulfide itself was later shown to be a good catalyst for the reaction reported and consequently the poisoning phenomenon may not be applicable to this case (308). 

Rhenium Sulfides and Selenides.208 209 These catalysts are characterized by their outstanding resistance to poisoning and minimal tendency to cause the hydrogenolysis of carbon-sulfur bonds than the base metal sulfides. Rhenium heptasulfide is easily prepared from boiling 6M hydrochloric acid solutions of perrhenate with hydrogen sulfide. It has been noted that occasional exposure of the dried, powdered catalyst to the atmosphere is not deleterious. 

Rhenium sulfide was the most active and hydrogenated excess ketone to the corresponding alcohols. The platinum metal sulfides were found to be more active than the base metal sulfides and highly selective for the formation of (V-alkylarylamines. They usually produce a pure product with little or no side reactions, require no excess above the stoichiometric amount of ketone, and are active at relatively low pressures of hydrogen. An example with (V-phenyl-p-phcnylencdiaminc is shown in eq. 6.15.37 Platinum metal sulfides may also be used for the reductive alkylation of aliphatic amines and their nitroalkane precursors with aliphatic ketones. 

Chemical name Technetium " Tc colloidal rhenium sulfide injection Ph. Eur.) Technetium Tc 99m sulfur colloid injection USP) " Tc-(Re)-sulfide colloid " Tc-sulfur colloid Listed trade names HepatoCis (TCK-1) (1) Sulfotec Sorin (2) ... 

Chemical name Rhenium sulfide nanocolloid Tin(ll)-sulfide nanocolloid "Tc-(Re)-sulfide nanocolloid 99mTc-(Sn)-sulfide nanocolloid Listed trade names NanoCis (TCK-17) (A-l-B) CIS Bio Lymphoscint (Solco) GE Healthcare... 

Kit components A Rhenium sulfide 0.48 mg Ascorbic acid 7.0 mg Gelatin 9.6 mg Water for injection 1.0 ml Hydrochloric acid (cone.) 37.4 pi Kit components B Sodium pyrophosphate-10H2O 3.0 mg Stannous chloride-2 H2O 0.5 mg... 

Tc-(Re)-sulfide colloid is formed by reduction with tin pyrophosphate in the boiling water bath. Rhenium sulfide is used as a carrier (Larson and Nelp 1966 Patton et al. 1966). The added Tc eluate should not exceed 2 ml, the Tc activity should not be less than 370 MBq (10 mCi). Gelatin is used as a stabilizer. The size distribution of Tc-(Re)-sulfide colloid is between 40 and 80 mn, comparable with the previously available Tc-(Sb)-sulfide colloid (5-15 nm). 

Rhenium sulfides are effective catalysts for hydrogenation of organic substances and they have the advantage over heterogeneous platinum metal catalysts in that they are not poisoned by sulfur compounds.811 An inorganic reduction that they catalyze is that of NO to N20 at 100°.8b... 

The crystal structures of every known ternary alkali-metal rhenium sulfide and se-lenide all contain [ReeXg] structural units in which X = S or Se. These structural... 

Alternate method Rhenium sulfides, oxides or rhenium metal are dissolved in HNO3. The solution is evaporated and diluted with ammonia. Recrystallization is required May be used to prepare pure rhenium (see p. 1476). 

This approach has been fashioned in the pursuit of molecular rhenium chalcogenide clusters whose structures have not been accessible by conventional self-assembly techniques. The method, which has been termed cluster excision, involves the addition of a suitable ligand to the nonmolecular solid, such that the vacant sites on the metal centers will be occupied upon cleavage of the bridging interactions. Ligands that have been utilized in this approach include Cl and CN , affording molecular rhenium sulfide and selenide clusters (Equation (21)). This method also allows access to previously known structures under milder synthetic conditions ... 

The following metal compounds are used for the preparation of the catalysts oxides, metal carbonyls, halides, alkyl and allyl complexes, as well as molybdenum, tungsten, and rhenium sulfides. Oxides of iridium, osmium, ruthenium, rhodium, niobium, tantalum, lanthanum, tellurium, and tin are effective promoters, although their catalytic activity is considerably lower. Oxides of aluminum, silicon, titanium, manganese, zirconium as well as silicates and phosphates of these elements are utilized as supports. Also, mixtures of oxides are used. The best supports are those of alumina oxide and silica. 

Enyashin, A.N., Popov, I. Seifert, G. (2009) Stability and electronic properties of rhenium sulfide nanotubes. Physica Status Solidi B-Basic Solid State Physics, 246,114-118. 

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