Molybdenum chloride, anhydrous

The electrosynthesis is rapid at room temperature and gram quantities of anhydrous chromium bromide may be obtained within a few hours. The chemical yield is 93%. Additionally, molybdenum chloride, M0CI2, has been prepared electrosynthetically,35 Eq. 7.8 ... 

Fused Salt Electrolysis. Only light RE metals (La to Nd) can be produced by molten salt electrolysis because these have a relatively low melting point compared to those of medium and heavy RE metals. Deposition of an alloy with another metal, Zn for example, is an alternative. The feed is a mixture of anhydrous RE chlorides and fluorides. The materials from which the electrolysis cell is constmcted are of great importance because of the high reactivity of the rare-earth metals. Molybdenum, tungsten, tantalum, or alternatively iron with ceramic or graphite linings are used as cmcible materials. Carbon is frequently used as an anode material. 

Undoubtedly, the best method for the production of pure anhydrous lanthanide trihalides involves direct reaction of the elements. However, suitable reaction vessels, of molybdenum, tungsten, or tantalum, have to be employed silica containers result in oxohalides (27). Trichlorides have been produced by reacting metal with chlorine (28), methyl chloride (28), or hydrogen chloride (28-31). Of the tribromides, only that of scandium has been prepared by direct reaction with bromine (32). The triiodides have been prepared by reacting the metal with iodine (27, 29, 31, 33-41) or with ammonium iodide (42). 

The molybdenum trioxide in the anhydrous material is volatilized in a stream of dry hydrogen chloride. The residue is weighed as impure silica. The silica is then determined by the loss in weight when volatilized with hydrofluoric and sulfuric acids. The molybdenum trioxide is calculated by difference. 

An intimate mixture of 50 g. of molybdenum(V) chloride with 150 g. of molybdenum powder (mesh size 100) prepared under anhydrous conditions is distributed uniformly along the length of the tube. Two glass-wool plugs (A and B in the figure) are placed about 15 cm. from the joints at the ends of the tube to... 

Molybdenum(III) chloride has been prepared in limited quantities by the reduction of molybdenum(V) chloride with hydrogen or molybdenum metal powder.1 2 The procedures give low yields and require several steps. The new procedure described here for the preparation of molybdenum (III) chloride gives a high yield and involves reduction of pure molybdenum(V) chloride, using anhydrous tin(II) chloride as a reducing agent. 

Excess molybdenum(V) chloride (13.66 g., 0.049 mole) and anhydrous tin(II) chloride (9.03 g., 0.047 mole) are ground to a fine powder with a mortar and pestle and then placed in the reaction vessel with the Teflon impeller. 

Infrared Data. The presence of moisture and/or oxygen bonds is easily detected by infrared analysis, and the spectra serve partly to indicate the type of contamination that might be present in anhydrous or oxygen-free compounds. Tin(II) chloride was studied as a hexachlorobutadiene mull, and molybdenum(V) chloride and molybdenum (III) chloride were studied as Nujol mulls. All starting materials and the final product were free of moisture, OH stretching, and molyb-denum-to-oxygen bonding, as indicated by the absence of absorptions at 3500, 1800, and 900-1020 cm 1, respectively. 

Formally, pentavalent neutral metallocorroles have been prepared by Murakami and coworkers.The first of these was the oxomolybdenum(V) corrole derivative 2.179. ° This complex was prepared by heating free-base corrole 2.82 with molybdenum pentachloride in oxygen-free decalin (Scheme 2.1.56). Alternatively, molybdenum hexacarbonyl (Mo(CO)e) could be used as the metal source. In both cases, oxidation to the oxomolybdenum complex 2.179 was believed to occur during workup (involving chromatography on neutral alumina followed by recrystallization). In this way, complex 2.179 was isolated in c. 40% yield. Similar yields of the oxochromium(V) complex 2.180 could be achieved via the reaction of 2.82 with anhydrous chromium(II) chloride in DMF. Here too, spontaneous oxidation during workup was used to afford the formally pentavalent oxo-complex 2.180. 

An ethereal solution of a Grignard reagent reacts readily with CO in the presence of anhydrous chromium(III) chloride (Job, 1927). One of the products is the ether-soluble Cr(CO)g. If the CrClg is replaced by MoClg orWClg the hexacarbonyl of molybdenum or tungsten is formed. 

Chromium forms a cyclopentadienyl compound similar to ferrocene (p. 499). Cyclopentadienyl sodium reacts with anhydrous chromium (I I) chloride in tetrahydrofuran to give red (C5H5)2Cr. By oxidising this, compounds containing the (C5H5)2Cr+ ion are easily obtained (Cotton and Wilkinson, 1954). When cyclopentadiene mixed with molybdenum or tungsten carbonyl is passed through a tube heated to 300 the dicyclopentadienyl hexacarbonyl is formed (Wilkinson, 1954) ... 

In a 500 mL round-bottomed flask are placed molybdenum pentachloride (65 g, 238 mmol), anhydrous aluminum chloride (140 g, 1.05 mol), and aluminum powder (8.5 g, 315 mmol), and the mixture is mixed well. To the mixture, benzene (250 mL) is added slowly over a period of ca 15 min. If the temperature of the contents increases too much on addition of benzene, the flask should be cooled by an ice bath. After the reaction mixture has cooled to room temperature, the flask is shaken well to mix the contents and a reflux condenser is attached. A Teflon sleeve should be put on the flask joint to prevent it from freezing and the condenser should be tightly wired to the neck of the flask. The nitrogen pressure is adjusted as 15-17 psi using mercury bubbler. The flask is immersed in the oil bath and the temperature of the bath is raised gradually to 120 °C. After refluxing for 12 h, the mixture is cooled to room temperature and the flask is shaken to mix the contents well. Then the flask is heated again under reflux for 12 h. After the flask has cooled to room temperature, the benzene layer is removed by... 

BTF is prepared industrially from toluene in two synthetic steps 1) free radical perchlorination of the methyl group, followed by 2) fluorine/chlorine exchange of the three chlorine atoms with anhydrous hydrogen fluoride (Scheme 1). The chlorination step may be catalyzed by light of suitable wavelength (UV) and is conveniently carried out in the liquid phase. The fluoride/chloride exchange can be catalyzed by the presence of metal halide compounds, such as pentahalide (Cl, F) salts of antimony and molybdenum, and is effected under a variety of... 

Disulfides. The reaction of sulfonyl chlorides (alkyl or aryl) with molybdenum hexacarbonyl in anhydrous tetramethylurea at 70° (N2) provides a convenient synthesis of disulfides. The metal carbonyl does not function as a catalyst ... 

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