Metal alkyl halide

NITROCARBOL (75-52-5) Forms explosive mixture with air (flash point 95°F/35°C). Thermally unstable. Shock, friction, pressure, or elevated temperature above 599°F/315°C can cause explosive decomposition, especially if confined. Violent reaction with strong oxidizers, alkyl metal halides, diethylaluminum bromide, formic acid, methylzinc iodide. Contact with acids, bases, acetone, aluminum powder, amines, bis(2-aminoethyl)amine, haolforms make this material more sensitive to explosion. Reacts, possibly violently, with ammonium hydroxide, calcium hydroxide, calcium hypochlorite, 1,2-diaminomethane, formaldehyde, hexamethylbenzene, hydrocarbons, hydroxides, lithium perchlorite, m-methyl aniline, nickel peroxide, nitric acid, metal oxides, potassium hydride, potassium hydroxide, sodium hydride. Mixtures with ammonia, aniline, diethylenetriamine, metal oxides, methyl amine, morpholine, phosphoric acid, silver nitrate form shock-sensitive compounds. Forms high-explosive compound with urea perchlorate. Mixtures with hydrocarbons and other combustible materials can cause fire and explosions. Attacks some plastics, rubber, and coatings. 

The metals that are more frequently found as components of Ziegler-Natta catalysts are some light elements of groups I-III of the periodic table (e.g., Li, Be, Mg, Al), present as organometaUic compounds and halides, or other derivatives of transition metals of groups IV-Vm (e.g., Ti, V, Cr, Mo, Rh, Rn, Co, and Ni). A typical example is the product(s) of the reaction between triethylaluminum and titanium tetrachloride. The composition of the product is not well defined but is believed to be either an alkylated metal halide (monometallic I) or a bimetallic complex involving a bridge between the two metals (II). 

Certain metal alkyls, MR , react with metal halides, MX , forming alkyl metal halides, e.g.,... 

The next major commodity plastic worth discussing is polypropylene. Polypropylene is a thermoplastic, crystalline resin. Its production technology is based on Ziegler s discovery in 1953 of metal alkyl-transition metal halide olefin polymerization catalysts. These are heterogeneous coordination systems that produce resin by stereo specific polymerization of propylene. Stereoregular polymers characteristically have monomeric units arranged in orderly periodic steric configuration. 

The importance of metal catalysis is suggested by the fact that exclusive 4-substitution of pyridine with alkyllithiums or alkyl-magnesium halides occurs when free metal is present exclusive 2-substitution otherwise occurs. 

The most spectacular case of products arising from a catalyst invention is that of the stereospecific hydrocarbon polymers made possible by the Ziegler-Natta work on aluminum alkyl/transition metal halide combinations around 1950. Until these catalysts existed, polypropylene, polyiso-prene, and cis-polybutadiene could not be made, and linear polyethylene could not be made cheaply. For each of these products, very large investments were needed in big plants and in market development before they were competitive with the established, big thermoplastics and rubbers. Entrance fees ran into tens of millions of dollars. 

Prior equilibrium. Consider the net reaction between certain metal halide and alkyl cobalt complexes, RCo + MX = Co+ + RM + X". There is a rapid equilibrium ... 

Primary alkyl amines RNHi can be convertedto alkyl halides by (1) conversion to RNTs2 (p. 447) and treatment of this with I or Br in DMF, or to N(Ts)—NH2 derivatives followed by treatment with NBS under photolysis conditions, (2) diazotization with terr-butyl nitrite and a metal halide such as TiCU in DMF, or (3) the Katritzky pyrylium-pyridinium method (pp. 447,489). Alkyl groups can be cleaved from secondary and tertiary aromatic amines by concentrated HBr in a reaction similar to 10-71, for example,... 

As shown in Table IV, the highest catalytic activity of metal halides used as Lewis acid for the alkylation reaction of ferrocene with 2 was observed in methylene chloride solvent. Among Lewis acids such as aluminum chloride, aluminum bromide, and Group 4 transition metal chlorides (TiCl4, ZrCU, HfCU), catalytic efficiency for the alkylation decrea.ses in the following order hafnium chloride > zirconium chloride > aluminum chloride > aluminum bromide. Titanium chloride... 

Group 14 metal halides also undergo metathesis reactions. For instance, organotin compounds are prepared on an industrial scale using organoaluminum reagents. These reactions take place because tin is a softer Lewis acid than aluminum, and carbon (in an alkyl group, represented by R) is a softer Lewis base than chlorine ... 

See alkyl nitrates Lewis acids See Other NON-METAL HALIDES... 

Dialkylamino derivatives of elements located in the periodic table to the left or below those listed above cannot be prepared by the above method due to either the ionic character of some of the inorganic halides or the formation of stable metal halide-amine addition products. Therefore, other methods must be applied. Dialkylamino derivatives of tin7 and antimony8 are conveniently obtained by reaction of the corresponding halides with lithium dialkylamides. Others, such as the dialkylamino derivatives of aluminum,9 are made by the interaction of the hydride with dialkylamines. Dialkylamino derivatives of beryllium10 or lithium11 result from the reaction of the respective alkyl derivative with a dialkylamine. 

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