Hydrogen cyanide Sohio acrylonitrile

Addition of Hydrogen Cyanide. At one time the predominant commercial route to acrylonitrile was the addition of hydrogen cyanide to acetylene. The reaction can be conducted in the Hquid (CuCl catalyst) or gas phase (basic catalyst at 400 to 600°C). This route has been completely replaced by the ammoxidation of propylene (SOHIO process) (see Acrylonitrile). 

Two synthesis processes account for most of the hydrogen cyanide produced. The dominant commercial process for direct production of hydrogen cyanide is based on classic technology (23—32) involving the reaction of ammonia, methane (natural gas), and air over a platinum catalyst it is called the Andmssow process. The second process involves the reaction of ammonia and methane and is called the BlausAure-Methan-Ammoniak (BMA) process (30,33—35) it was developed by Degussa in Germany. Hydrogen cyanide is also obtained as a by-product in the manufacture of acrylonitrile (qv) by the ammoxidation of propjiene (Sohio process). 

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 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,... 

The process was developed by Monsanto to use the hydrogen cyanide byproduct of acrylonitrile from the Sohio process [64], However, synthetic lactic acid is not as competitive as that from the fermentation of starch or sugar [65]. 

The latest developments in catalysts for manufacturing acrylonitrile are those of the Japanese-firm Nitto Chemical, which commercialized a system in 1974 based on doped antimony and iron, called NS 733A or catalyst 13, offering higher productivity in comparison with Sohio catalyst 41. as well as lower production of acetonitrile and hydrogen cyanide by-products. 

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 is an essential chemical for the production of methacryhc esters, adipodinitrUe, and some technical important amino acids, such as L-methio-nine. Alongside the two mentioned synthetic routes from methane, considerable amounts of HCN are also formed as a side product of acrylonitrile synthesis using the Sohio process (Section 5.3.3.8). 

Sohio Acrylonitrile Process. This process, developed in the late 1950s by Standard Oil Company of Ohio, produces hydrogen cyanide and acetonitrile as by-products of acrylonitrile production. Ironically, the manufacture of acrylonitrile used to be the largest consumer of HCN until the Sohio process became the principal source of acrylonitrile in the 1960s. The by-product from the Sohio process was estimated to have supplied 20 percent of the HCN demand in 1990. The chemistry involves ... 

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