Cadmium, dialkyl

For most purposes the use of 1.0 mol of an alkyl or aryl bromide (for the preparation of the cadmium dialkyl or diaryl through the Grignard reagent) to 0.8 mol of the acid halide is recommended. This results in nearly equivalent molar ratios of the cadmium dialkyl and the acid halide, since the overall yield of the former is usually about 80 per cent. The entire preparation can be carried out in one flask without the isolation of intermediates. Experimental details are given for the preparation of l-chlorohexan-2-one (Expt 5.94). 

TABLE III,—ATOMIC REFRACTION AND DISPERSION OF CADMIUM DIALKYLS. 

The chlorides of zinc and cadmium, on the other hand, react with only one alkyl group of the trialkyl alane and form zinc and cadmium dialkyls ZnCl2 + 2A1Rj -> ZnR2 + 2R2A1C1... 

Pure cadmium dialkyls are rather unstable and prone to thermal decomposition. 

Organometallics, such as dialkyl zinc or cadmium-alkyl or aryl lithium Alkali acetylides Diels-Alder Arndt-Eistert... 

The reaction of quinolinium and isoquinolinium salts with dialkyl cadmium has been observed to be slow and occurs in relatively poor yield. The structures of the products are the same as those obtained from reactior with Grignard reagents and the yields ranged from 0-20% (40). Leadini references to other observed reactions of quinolinium and isoquinoliniuir salts with Grignard reagents can be found in the above cited review (31). 

In terms of their chemical behavior, dialkylzinc compounds generally react to transfer alkyl groups to other metals. Dialkyls of cadmium are usually prepared by the reaction of a Grignard reagent with a cadmium halide. 

Physical Form, brown to black oily liquid new mineral-based crankcase oil contains petrochemicals (straight-chain hydrocarbons, aromatic hydrocarbons, and polyaromatic hydrocarbons or PAH) plus stabilizers and detergents including zinc dithiophosphate, zinc diaryl or dialkyl dithiophosphates (ZTDP), calcium alkyl phenates, magnesium, sodium, and calcium sulfonates, tricresyl phosphates, molybdenum disulfide, heavy metal soaps, cadmium, and zinc. ... 

Many dialkyl and diaryl cadmium compounds have found use as polymerization catalysts. For example, the diethyl compound catalyzes polymerization of vinyl chloride, vinyl acetate, and methyl methacrylate (45), and when mixed with TiCl can be used to produce polyethylene and crystalline polypropylene for filaments, textiles, glues, and coatings (45). With >50% TiCl diethyl cadmium polymerizes dienes. Diethyl cadmium maybe used as an intermediate ethylating agent in the production of tetraethyllead. The diaryl compounds such as diphenylcadmium [2674-04-6]> (C H Cd, (mp 174°C) are also polymerization catalysts. These compounds are also prepared using Grignard or arylUthium reagents in tetrahydrofiiran (THF) solvent but may be prepared by direct metal substitution reactions such as ... 

Pyrrole- and indole-carboxylic acid chlorides react with dialkyl- and diaryl-cadmium to yield the ketones and it is noteworthy that the reaction of the anhydride of indole-2,3-dicarboxylic acid with diphenylcadmium produces 3-benzoylindole-2-carboxylic acid and not its isomer (53JCS1889). The ability of l-methylindole-2-carboxylic acid to react with nucleophiles is enhanced by conversion into the mixed anhydride with methanesulfonic acid. The mixed anhydride reacts with carbanions derived from diethyl malonate and from methyl acetate to yield the indolyl (3- keto esters (80TL1957). 

Te tram eric alkyl beryllium, zinc and cadmium alkoxides are formed by controlled alcoholysis of the metal dialkyls,16U62 while cubanoid thallium alkoxides are obtained by reaction of the metal with refluxing ethanol, and alcohol metathesis.163 Reaction (4) affords a tin phosphide cubane in low yield 164... 

Lead, cadmium, mercury, cobalt, uranium, antimony, barium, beryllium, cesium, molybdenum, platinum, thallium, tungsten, organochlorine pesticides, organophospho-rus insecticides (dialkyl phosphate metabolites), (specific metabolites), pyrethroid pesticides, other pesticides (2-isopropoyxyphenol, carbofuranphenol), herbicides, phthalates, phytoestrogens, polycyclic aromatic hydrocarbons, polychlorinated dibenzo-p-dioxins and dibenzofurans, polychlorinated biphenyls, tobacco smoke... 

One of the best known reactions of dialkyl cadmium compounds is that with acyl halides which results in the formation of ketones. The reactions of (CF3)2Cd glyme with CH, COBr and C6HhCOC1 were the third class of reactions of the trifluoromethylating reagent examined. However, the mixed trifluoromethylalkyl or -aryl ketones were not observed. The organic products obtained were the acyl fluorides (95% yield) along with difluorocarbene. The latter could be stereospecifically trapped at temperatures as low as -78°C. The addition of either lithium or magnesium halides to the reaction mixture did not affect the outcome (106). 

Dimethylcadmium, (CH3)2Cd, is an oily liquid at room temperature and has a very unpleasant odor. The compound melts at -4.5"C and boils at 106°C. It decomposes in contact with water. Diethyl-cadmium is likewise an oil it melts at -21°C, boils at 64°C, and reacts explosively with oxygen in air. Dipropylcadmium, (C3H7)2Cd, is an oil that melts at -83°C, boils at 84°C, and reacts with water. The dialkyl cadmium compounds are distillable, but decompose above about 150°C, evolving toxic cadmium fume. 

Dialkyl cadmium was employed to convert ort/io-substituted phenyl tellurium halides to unsymmetrical diorgano tellurium products. These conversions were accomplished without affecting the carbonyl groups present in the molecules. 

The dialkyls and diaryls are colorless liquids or low-melting solids. They react less readily than their zinc and cadmium analogues with air and water, but they are thermally and photochemically unstable, with homolytic Hg—C bond cleavage being the key in their decomposition. They may be kept for several months in the dark at room temperature. All are toxic. 

Polymers of benzoquinone, some tin-containing polymers, like poly(dialkyl tin maleate), zinc or cadmium containing polycondensates of 8-hydroxyquinoline with formaldehyde, polymers containing phosphorus, Ar,Ar -diphenylguanidine, 4-ami-no-1,2,3-triazole, benzothiazole, benzimidazole, benzothiazolone or dithiocarba-mate moieties were reported as thermostabilizers for PVC [67, 325-327]. 

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