Hydrogen cyanide acetonitrile

Commercial development of a range of cycloalkene-cobalt homogeneous catalysts has prompted their application in the synthesis of pyridine and 2-substituted pyridines. Thus, bis(cyclopentadienyl)cobalt catalyzes the reaction of acetylene with hydrogen cyanide, acetonitrile or acrylonitrile to yield pyridine, 2-methylpyridine and 2-vinylpyridine respectively (Scheme 4 R = H, Me or CH=CH2) (76S26, 78AG(E)505, 75BEP846350). The high cost of the catalyst has so far limited full commercial realization of this route. Acrylonitrile... 

This transformation is also characterized by the importance assumed by degradation side reactions of propylene and of its oxygen and nitrogen derivatives, which lead simultaneously to the formation of hydrogen cyanide, acetonitrile, nitrogen, carbon monoxide and carbon dioxide ... 

Woolley and Fardell conducted comprehensive investigations of flexible and rigid polyurethane foams, including laboratory and full-scale experiments. It was established that a characteristic yellow smoke evolved from the polyurethanes at 200 to 300 °C, especially from the toluylene diisocyanate-based flexible foams. The yellow smoke comprised the total nitrogen content of the original polyurethane and amounted to about 25 per cent m/m of the foam. It was supposed that the thermally released isocyanate polymerized immediately in some way to form a particulate material (the solid part of the yellow smoke). Its apparent decomposition temperature was about 800 C. Mass spectrometry of its decomposition products detected hydrogen cyanide, acetonitrile, pyridine, and benzonitrile. The proportion of HCN increased with temperature. 

The features of the original proeess as reported by Kunii and Levenspiel (1991a) and some recent developments follow. Reaetor operating eonditions are 400 to 500°C at about 1.7 atmosphere, with a reactor contact time of 5 to 20 seconds. In addition to acrylonitrile, carbon monoxide, carbon dioxide and water, small quantities of hydrogen cyanide, acetonitrile, and acrolein are also produced. The original plants were designed to operate at around 52 cm/s superficial velocity. Modern plants are now operating with fines... 

Methyl-2-thiabutane 3-Thiapentane 3,4-Dithiahexane Thiacyclopentane Thiacyclohexane Thiophene 3-Methylthiophene 2-Methylthiophene Benzenethiol Cyanogen Hydrogen Cyanide Acetonitrile Acrylonitrile Pyridine... 

Amm oxida tion, a vapor-phase reaction of hydrocarbon with ammonia and oxygen (air) (eq. 2), can be used to produce hydrogen cyanide (HCN), acrylonitrile, acetonitrile (as a by-product of acrylonitrile manufacture), methacrylonitrile, hen onitrile, and toluinitnles from methane, propylene, butylene, toluene, and xylenes, respectively (4). 

Yields based on propylene are 50—75%, and the main by-products are acetonitrile and hydrogen cyanide (96). 

Carbon monoxide, propylene, propane, hydrogen cyanide, acrylonitrile, acetonitrile NOj from by-product incinerator... 

Cyanogens Cyanogens Hydrogen cyanide Cyanogen chloride Cyanogen bromide Cyanogen iodide Acetonitrile Acrylic nitrile... 

Acetonitrile and hydrogen cyanide are hy-products that may he recovered for sale. Acetonitrile (CH3CN) is a high polarity aprotic solvent used in DNA synthesizers, high performance liquid chromatography (HPLC), and electrochemistry. It is an important solvent for extracting butadiene from C4 streams. Table 8-1 shows the specifications of acrylonitrile, HCN, and acetonitrile. ... 

Hydrogen cyanide, wt-ppm Acetonitrile, wt-ppm Acetaldehyde, wt-ppm Acrolein, wt-ppm Acetone, wt-ppm Peroxides (as H2O2), wt-ppm Water, wt %... 

Made by the reaction of propylene with ammonia and air (the Sohio process). This is the basis for the production of all of the acrylonitrile made in the world. Recoverable and salable by-products include hydrogen cyanide (HCN) and acetonitrile (CH3CN). 

The upper layer which contains, in addition to acrylonitrile, hydrogen cyanide, acrolein, acetonitrile, and small quantities of other impurities, passes to a second reactor (E) where, at a suitable pH, all the acrolein is converted to its cyanohydrin. (Cyanohydrins are sometimes known as cyanhydrins.) The product from the reactor (E) is fed to a cyanohydrin separation column (F), operating at reduced temperature and pressure, in which acrolein cyanohydrin is separated as the bottom product and returned to the ammox-idation reactor (A) where it is quantitatively converted to acrylonitrile and hydrogen cyanide. 

Acrylonitrile Acetonitrile Carbon dioxide Hydrogen cyanide Acrolein... 

Most protic solvents have both protogenic and protophilic character, i.e. they can split off as well as bind protons. They are called, therefore, amphiprotic. These include water, alcohols, acids (especially carboxylic), ammonia, dimethylsulphoxide and acetonitrile. Solvents that are protogenic and have weak or practically negligible protophilic character include acid solvents, such as sulphuric acid, hydrogen fluoride, hydrogen cyanide, and formic acid. 

Acetonitrile (C2H3N, g)) bums to form hydrogen cyanide (1 ICN(g)), carbon dioxide and water vapor. 

Copper-catalyzed monoaddition of hydrogen cyanide to conjugated alkenes proceeded very conveniently with 1,3-butadiene, but not with its methyl-substituted derivatives. The most efficient catalytic system consisted of cupric bromide associated to trichloroacetic acid, in acetonitrile at 79 °C. Under these conditions, 1,3-butadiene was converted mainly to (Z )-l-cyano-2-butene, in 68% yield. A few percents of (Z)-l-cyano-2-butene and 3-cyano-1-butene (3% and 4%, respectively) were also observed. Polymerization of the olefinic products was almost absent. The very high regioselectivity in favor of 1,4-addition of hydrogen cyanide contrasted markedly with the very low regioselectivity of acetic acid addition (vide supra). Methyl substituents on 1,3-butadiene decreased significantly the efficiency of the reaction. With isoprene and piperylene, the mononitrile yields were reduced... 

The gases (unreacted propylene, CO2, and air) are removed in an absorption column. The rest of the products go with the aqueous solution to be separated in a series of fractionating columns. The major by-products are water, CO2, acetonitrile, and hydrogen cyanide. 

Note Inhibited with 35-45 ppm hydroquinone monomethyl ether to prevent polymerization during storage and transport (Acros Organics, 2002). Commercial grades may contain the following impurities acetone and acetonitrile (300-500 ppm), acetaldehyde and propionaldehyde (300-500 ppm), acrolein, methanol, isopropanol and hydrogen cyanide (300-500 ppm) (NICNAS, 2000)... 

Chemical/Physical. Reacts with OH radicals possibly forming acetaldehyde or acetamide (Atkinson et al, 1978). When ethylamine over kaolin is heated to 600 °C, hydrogen and acetonitrile formed as the major products. Trace amounts of ethylene, ammonia, hydrogen cyanide, and methane were also produced. At 900 °C, however, acetonitrile was not produced (Hurd and Carnahan, 1930). 

By-products of this reaction are acetonitrile, CH3-C=N, and hydrogen cyanide. This is now a major source of these two materials. Interestingly, the C2 by-product acetonitrile has a bp of 81.6 °C, whereas acrylonitrile with three carbons has a lower bp of 77.3 °C, quite an unusual reversal of this physical property s dependence on molecular weight. The TWA of acrylonitrile is 2 ppm and it is on the list of Reasonably Anticipated to Be Human Carcinogens. ... 

The most frequently used method for the preparation of isoquinoline Reissert compounds is treatment of an isoquinoline with acyl chloride and potassium cyanide in water or in a dichloromethane-water solvent system. Though this method could be successfully applied in a great number of syntheses, it has also some disadvantages. First, the starting isoquinoline and the Reissert compound formed in the reaction are usually insoluble in water. Second, in the case of reactive acyl halides the hydrolysis of this reaction partner may became dominant. Third, the hydroxide ion present could compete with the cyanide ion as a nucleophile to produce a pseudobase instead of Reissert compound. To decrease the pseudobase formation phase-transfer catalysts have been used successfully in the case of the dichloromethane-water solvent system, resulting in considerably increased yields of the Reissert compound. To avoid the hydrolysis of reactive acid halides in some cases nonaqueous media have been applied, e.g., acetonitrile, acetone, dioxane, benzene, while utilizing hydrogen cyanide or trimethylsilyl cyanide as reactants instead of potassium cyanide. 

Acetone, Sulfuric acid. Chlorine gas. Methylene chloride. Calcium chloride Acetone, Sulfuric acid. Chlorine gas. Chloroform, Calcium chloride Dimethoxy ethane, Nitrate trihydrate. Liquid hydrogen cyanide 3-Pyridol, Ethylmethylamine, Formaldehyde, Pyridine, Dimethylcarbamoyl chloride, Sodium carbonate, Chloroform, Sodium sulfate, 1,10-Dibromodecane, Acetone, Acetonitrile, Charcoal, Ethyl acetate... 

Acrylonitrile of 99.5-99.7% purity is available commercially, with the following specifications (ppm by weight, maximum) acidity (as acetic acid), 10 acetone, 75 acetonitrile, 300 acrolein, 1 hydrogen cyanide, 5 total iron, 0.1 oxazole, 10 peroxides (as hydrogen peroxide), 0.2 water, 0.5% and nonvolatile matter, 100. Hydroquinone monomethyl ether (MEHQ) is added as an inhibitor at concentrations of 35-45 mg/kg (ppm) (Cytec Industries, 1994, 1997). Trade names for acrylonitrile include Acritet, Acrylon, Carbacryl, Fumigrain and Ventox. 

Fig. 14.10 Reaction path diagram [149] illustrating major steps in volatile-N conversion in flames for different nitrogen species hydrogen cyanide (HCN), ammonia (NH3), cya-nuric acid (HNCO), acetonitrile (CH3CN), and pyridine (C5H5N). The diagram is based on chemical kinetic modeling at moderate fuel-N concentrations. Solid lines denote elementary reaction pathways, while dashed arrows denote routes that involve intermediates and reactions not shown.

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