Methyl cyanide toxicity

Note Highly polar solvent sweet, ethereal odor soluble in water flammable, burns with a luminous flame highly toxic by ingestion, inhalation and skin absorption miscible with water, methanol, methyl acetate, ethyl acetate, acetone, ethers, acetamide solutions, chloroform, carbon tetrachloride, ethylene chloride, and many unsaturated hydrocarbons immiscible with many saturated hydrocarbons (petroleum fractions) dissolves some inorganic salts such as silver nitrate, lithium nitrate, magnesium bromide incompatible with strong oxidants hydrolyzes in the presence of aqueous bases and strong aqueous acids. Synonyms methyl cyanide, acetic acid nitrile, cyanomethane, ethylnitrile. 

Acetonitrile (PerSeptive Biosystems, Framingham, MA), also known by the synonyms methyl cyanide, cyanomethane, ethanenitrile, and ethyl nitrile, is rather toxic and precautions should be taken. 

Despite the fact that one of its less commonly used names is methyl cyanide, ACN is not particularly toxic although its smell is not an adequate indication of its presence at its TLV of 40 ppm. It is particularly harmful to the eyes and great care should be taken in wearing goggles when handling ACN. 

Hydrogen cyanide (prussic acid) is a liquid with a boiling point of 26°C. Its vapour is flammable and extremely toxic. The effects of acute exposure are given in Table 5.34. This material is a basic building block for the manufacture of a range of chemical products such as sodium, iron or potassium cyanide, methyl methacrylate, adiponitrile, triazines, chelates. 

Yu, XZ, Gu J-D (2006) Uptake, metabolism, and toxicity of methyl ter/-butyl ether (MTBE) in weeping willows. J Hardz Mat B137 1417-1423 Yu, XZ, Gu J-D (2007a) Differences in Michaelis-Menten kinetics for different cultivars of maize during cyanide removal. Ecotoxicol Environ Saf 67 254-259... 

A more efficient and convergent industrial-scale synthesis that avoids toxic methyl iodide and sodium cyanide was developed (Scheme 15.2). Condensation of N,N-dimethyl-2,2-dimethoxyacetamide with imidazopyridine 7 under acidic conditions afforded hydroxy derivative 12. Conversion of the hydroxyl group to a chloride with thionyl chloride followed by reductive removal of the chloride with sodium borohydride provided zolpidem. 

The reaction has been shown to be of very broad scope with a multitude of nucleophiles Nu such as imides.23,24,29,32,33,36,37,42 amines,10,32 cyanide,25,32 hydroxide,10,32 alkox-ide,10,26,32 electron-rich isocyclic or heterocyclic aromatic compounds,28 carboxamides,31 lactams,31 ureas,31 sulfonamides,31 cyanate,31 formate (to give products with Nu = H),34 C-H acidic compounds,35 hydrazines and hydrazides,38 and sulfinates.38 The amino group NR R2 of cyclopropane-1,1-diamines and the nucleophile Nu in bicycles 8, 9 or 12, respectively, can be easily replaced with other nucleophiles Nu, such as water,10,32,33 alkoxide,10,32-34,42 Grignard compounds,27,42 amines,29,30,36,37,42,43 cyanide,29,33,42,44 hydride,34,42,44 and C-H acidic compounds39-41,43,44 (see Section 5.2.1.). Therefore, it is currently the most important method for the preparation of substituted bicyclic cyclopropylamines. The toxic and costly reagent methyl fluorosulfate can be avoided in a modified synthetic route, which instead of the fluorosulfate 5 proceeds via the corresponding tetraphenylborate, hexafluorophosphate, or (most conveniently) via the tosylate.23 The different steps of the method can often be combined in a one-pot procedure. Results are summarized in Table 3. 

Butane has been isomerized to isobutane in 95% yield (at 24.5% conversion) with platinum/Cs2 5H0.5PW12O40 at 200-300X. under hydrogen at 0.05 atm.294 The hydrogen reduced deactivation of the catalyst. The oxidation of isobutane to isobutylene is needed for the synthesis of tert-butyl methyl ether to put into gasoline. Isobutylene, in turn, can be oxidized to methacrylic acid for conversion to methyl methacrylate, an important monomer (6.56). Making methyl methacrylate this way avoids the use of toxic hydrogen cyanide in the present commercial process. 

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