Hydrogen cyanide industrial production

Racemic DL-lactic acid can be synthesized by fermentation using appropriate bacteria Lactobacillus helvetics in Table 1.1), but it is more easily synthesized by following the chemical process shown in Scheme 1.3. Here, the DL-lactic acid is produced by hydrolysis of lactonitrile that is generally formed by the addition reaction of acetaldehyde and hydrogen cyanide. Industrially, the lactonitrile is obtained as a by-product of acrylonitrile production (Sohio process).The lactic acid thus prepared is purified by distillation of its ester as described above. 

Hydrogen Cyanide Process. This process, one of two used for the industrial production of malonates, is based on hydrogen cyanide [74-90-8] and chloroacetic acid [79-11-8]. The intermediate cyanoacetic acid [372-09-8] is esterified in the presence of a large excess of mineral acid and alcohol. 

Ammonia is consumed in the manufacture of ammonium phosphates and ammonium sulfate by reaction with phosphoric acid and sulfuric acid, respectively. The phosphates may contain ortho- and polyphosphate values. Ammonium sulfate is also a by-product from other ammonia-using industries such as caprolactam (qv) and hydrogen cyanide (see Cyanides). 

Used in agriculture as a fertilizer and defoliant in the manufacture of nitric acid, hydrazine, hydrogen cyanide, urethanes, acrylonitrile, nitrocellulose, nitroparaffins, melamine, ethylene diamine, and sodium carbonate as an intermediate in producing explosives, synthetic fibers and dyes and used industrially as a refrigerant gas, neutralizing agent in the petroleum industry, latex preservative, and the production of fuel cells. 

Knapsack A process for making acrylonitrile from lactonitrile, itself made from acetaldehyde and hydrogen cyanide. Operated in Germany from 1958. Not industrially significant today for the production of acrylonitrile, although part of the process is still used for making lactic acid in Japan. 

Hydrogen cyanide (HCN) is a colorless, rapidly acting, highly poisonous gas or liquid that has an odor of bitter almonds. Most HCN is used as an intermediate at the site of production. Major uses include the manufacture of nylons, plastics, and fumigants. Exposures to HCN may occur in industrial situations as well as from cigarette smoke, combustion products, and naturally occurring cyanide compounds in foods. Sodium nitroprusside (Na2[Fe(CN)5 N0]-2H20), which has been used as an antihypertensive in humans, breaks down into nonionized HCN. 

The Toxics Release Inventory (TRI), which contains this information for 1992, became available in May of 1994. This database will be updated yearly and should provide a list of industrial production facilities and emissions. Information in the TRI93 (1995) data base pertains only to U.S. industrial facilities that manufacture or process hydrogen cyanide. There is a need for similar information on releases and off-site transfer from facilities that manufacture or process other cyanide compounds covered in this profile. 

Hydrogen cyanide undergoes many important organic reactions forming a variety of industrial products. Probably the most important reaction is the addition of the carbonyl ( =C=0) group. It adds to the carbonyl groups of aldehydes and most ketones forming cyanohydrins ... 

Hydrogen cyanide is an important building block chemical for the synthesis of a variety of industrially important chemicals, such as 2 hydroxy-4 methylthiobutyric acid, adiponitrile, nitrilotriacetic acid, lactic acid, and methyl methacrylate. The primary commercial routes to hydrogen cyanide are the reaction of methane and ammonia under aerobic (Andrussow Process) or anaerobic conditions (Degussa Process), or the separation of hydrogen cyanide as a by-product of the ammoxidation of propylene < ) The ammoxidation of methanol could represent an attractive alternate route to HCN for a number of reasons. First, on a molar basis, the price of methanol has become close to that of methane as world methanol capacity has increased. However, an accurate long term pricing picture for these two raw... 

Poisoning with cyanide may occur in a variety of ways accidental or intentional poisoning with cyanide salts, which are used in industry or in laboratories as a result of exposure to hydrogen cyanide in fires when polyurethane foam burns from sodium nitroprusside, which is used therapeutically as a muscle relaxant and produces cyanide as an intermediate product and from the natural product amygdalin, which is found in apricot stones, for example. 

There are several laboratory-size methods for synthesizing amino acids, but few of these have been scaled up for industrial production. Glycine and m.-alanine are made by the Stnecker synthesis, commencing with formaldehyde and acetaldehyde, respectively. In tile Strecker synthesis, aldehydes react with hydrogen cyanide and excess ammonia to give amino niiriles which, in turn, are converted into a -amino adds upon hydrolysis. 

Addition of hydrogen cyanide to a terminal alkene is catalyzed principally by nickel and palladium complexes. The reaction may give either linear or branched products (equation 161). The reaction is of considerable industrial interest. A review on the earlier work is available.599... 

Hydrogen cyanide (HCN) is a widely used high-volume raw and intermediate material in the world chemical industry. For the last several decades it has been increasingly supplied as a by-product of propylene ammoxidation—by... 

Acrylonitrile is a commodity monomer raw material for many fibers, plastics, rubbers, and chemical intermediates. Economically recoverable quantities of by-product hydrogen cyanide may be produced which are purchased by industrial consumers or, as necessary, disposed of by incineration. 

The initial drive for acrylonitrile (AN) production (6.2 Mt/a in 2004 worldwide) was the discovery, in the late 1930s, of the synthetic rubber Buna N. Today nitrile rubbers represent only a minor outlet for AN which is utilized primarily for polymerization to give textile fibres (50%) and ABS resins (24%), and for dimerization to adiponitrile (10%). Early industrial processes depended on the addition of hydrogen cyanide to acetylene or to ethylene oxide, followed by the dehydration of intermediate ethylene cyanohydrin. Both processes are obsolete and are now supplanted by the ammoxidation of propylene (Equation 34) introduced in 1960 by Standard Oil of Indiana (Sohio). The reason for the success stems from the effectiveness of the catalyst and because propylene,... 

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