Magnesium alkyl compounds

Atid aie pioduced by passing carbon dioxide into tlie ether bolution of the magnesium alkyl compound. 

When the magnesium alkyl compound does not form readily, i. e. in using aryl halides, a crystal of iodine is often added to start the reaction. Other solvents than ether have been used, i. e. anisole, phenyl amyl ether, and dimethyl-aniline. The solvent apparently combines with the compound MgRX forming intermediate products R20.MgRX and R3N.MgRX, and acts as a catalyst, since it has been found that the reactions proceed in benzene or xylene provided a small amount of ether or dimethyl-aniline be added. 

Standard Nd-based catalysts comprise binary and ternary systems. Binary systems consist of Nd chloride and an aluminum alkyl or a magnesium alkyl compound. In ternary catalyst systems a halide free Nd-precursor such as a Nd-carboxylate is combined with an Al- or Mg-alkyl plus a halide donor. By the addition of halide donors to halide-free catalyst systems catalyst activities and cis- 1,4-contents are significantly increased. In quaternary catalyst systems a solubilizing agent for either the Nd-salt or for the halide donor is used in addition to the components used in ternary systems. There are even more complex catalyst systems which are described in the patent literature. These systems comprise up to eight different catalyst components. 

Grignard Reaction.— The magnesium alkyl compounds had been known but not used in synthetic reactions until 1899 when Barbier and in 1900 Grignard used them in this way. Since then the applications of the general reaction have been very numerous. It is known as the Grignard Reaction and may be illustrated as follows ... 

Magnesium haUde and alkyl magnesium haUde precipitate and the alkyl magnesium compound remains in solution. Filtration (qv) followed by drying the filtrate yields soHd magnesium alkyl (11). Another preparation method is that of metal exchange using mercury alkyl in ether. 

Uses. Magnesium alkyls are used as polymerization catalysts for alpha-alkenes and dienes, such as the polymerization of ethylene (qv), and in combination with aluminum alkyls and the transition-metal haUdes (16—18). Magnesium alkyls have been used in conjunction with other compounds in the polymerization of alkene oxides, alkene sulfides, acrylonitrile (qv), and polar vinyl monomers (19—22). Magnesium alkyls can be used as a Hquid detergents (23). Also, magnesium alkyls have been used as fuel additives and for the suppression of soot in combustion of residual furnace oil (24). 

From a synthetic point of view, direct alkylation of lithium and magnesium organometallic compounds has largely been supplanted by transition-metal-catalyzed processes. We will discuss these reactions in Chapter 8 of Part B. 

In addition to magnesium, there is an extensive chemistry of organoberyllium compounds. The alkyl compounds are obtained most conveniently by the reaction of beryllium chloride with a Grignard reagent. 

Markl, Lieb and Merz have described the carbanionic addition of lithium or magnesium organometallic compounds to the P atom of 2.4.6-triphenyl-X -phos-phorins, which form deep red s ts 143. These can be alkylated either at the P atom to form X -phosphorins 144 or at C—2 to yield 1,2-dihydro-X -phosphorins 145. Acylation with benzoylchloride affords the 1,4-dihydro-X -phosphorin derivatives 146. Addition of acids or water leads to the synthetically important intermediates 147 which can be reconverted to the X -phosphorin-salts 143 by 2 N NaOH. 

Fuel additives - [AMNES-CYCLOALIPHATIC AMINES] (Vol 2) - [SULFONIC ACIDS] (Vol 23) -arsenic compds as [ARSENIC COMPOUNDS] (Vol 3) -boron compds as [BORON COMPOUNDS - BORIC ACID ESTERS] (Vol 4) -coordination compounds as [COORDINATION COMPOUNDS] (Vol 7) -ethers m [ETHERS] (Vol 9) -magnesium alkyls as [MAGNESIUM COMPOUNDS] (Vol 15) -polyamines as [DIAMINES AND HIGHER AMINES ALIPHATIC] (Vol 8) -htanates as [TITANIUM COMPOUNDS - ORGANIC] (Vol 24) -use of copper compounds [COPPER COMPOUNDS] (Vol 7)... 

Reaction IX. (b) Action of Heat on the Compound formed by treating Magnesium Alkyl or Aryl Halide with a Ketone in absolute Ethereal Solution (Grignard). (B., 35, 2647.)—When the Grignard reagent is treated with a ketone, the following reaction occurs —... 

Reaction IX. (c) Action of Dimethyl Sulphate on Magnesium Alkyl or Aryl Halide (Grignard).—When a Grignard compound is treated with dimethyl sulphate, methylation of the alkyl or aryl group takes place, the metal-halogen residue being split off. (B., 36,2116. See also O.S., XI., 66.)... 

Reaction XLIII. (c) Condensation of a-Halogen Fatty Acid Esters with Aldehydes and Ketones by means of Zinc or Magnesium (Reformatsky-Grignard). (C., (1901), I., 1196 II., 30 (1902), I., 856.)—This is an extension of the Grignard and zinc alkyl reactions which enables a-halogen esters to be condensed with carbonyl compounds as if they were simple alkyl halogen compounds. The zinc or magnesium alkyl derivative is neither prepared beforehand nor isolated in the reaction, but there is little doubt that some such compound is transitorily formed. Zinc is the metal... 

J. Houben obtained methane, etc., by the action of magnesium alkyl haloids on the hydrazines the action of zinc ethyl and magnesium alkyl haloids on hydrazine has been studied by R. L. Krause the action of mono- and di- chloroacetic acids, by Jit. Busch and E. Meussdorffer ethyl chloroacetate, by A. Reissert and W. Kayser, and M. Busch and eo-workers phenylglyoxalic acid, by A. Elbers dinitrophenylhydrazine, by T. Curtius and M. Mayer ethyl dinitrobenzoate, by T. Curtius and A. Riedel dinitrobenzoic add, by T. Curtius and H. E. Bollenbach nitro- and amido-phthalhydrazides, by T. Curtius and A. Hoesch formaldehyde, by E. Riegler, and E. Rimini carbonyl compounds, by... 

Many organo-metallic compounds can be preparod by digesting an ethereal solution of the magnesium alkyl or aryl halide with the metallic halogen coin- -pound. 

Calcium has received some application in organic synthesis similar to that of magnesium alkyl and aryl compounds, CaRa, have been prepared, and it seems likely that many of the magnesium syntheses, already mentioned, could be accomplished by the use of calcium. 

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