And ammonia synthesis

Further stages are required to assure conversion and to remove carbon dioxide or carbon monoxide from the gas mixture. A mixture of ammonia and synthesis gas (CO + H2) results from the reaction with nitrogen so the two must be separated and the synthesis gas recycled. 

F.J. Brykowski (ed.) Ammonia and Synthesis Gas, Noyes Data Corp., Park Ridge, N.J., 1981,... 

Noyes R (1964) Ammonia and synthesis gas 1964. Noyes Development Coporation, New York... 

Brykowski FJ (ed) (1981) Ammonia and synthesis gas recent and energy-saving processes, Noyes Data Corporation, Park Ridge, p 1... 

Noyes R (1967) Ammonia and synthesis gas 1967. Noyes Development Corporation, Park Ridge p 94... 

Hantzsch synthesis The formation of pyridine derivatives by the condensation of ethyl acetoacetate with ammonia and an aldehyde. Also applied to similar syntheses of pyrroles. 

Alkanolamines with at least one NCH2CHOHCH,i grouping. Important materials include monoisopropanolamine NHX H CHOHCH, b.p. 159 C di-iso-propanolamine NH(CH CHOHCH b.p. 248 C triisopropanolamine NtCH -CHOHCHi). , b.p. 300 C. Manufactured from ammonia and propylene oxide. U ed, is weedkillers, as stabilizers for plastics, in detergents, alkanolaniine soaps for sweetening natural gas and in synthesis. 

Oxygen enrichment of steel blast furnaces accounts for the greatest use of the gas. Large quantities are also used in making synthesis gas for ammonia and methanol, ethylene oxide, and for oxy-acetylene welding. 

A similar reaction in which ammonia and carbon dioxide are heated under pres sure IS the basis of the industrial synthesis of urea Here the reactants first combine yielding a salt called ammonium carbamate... 

Aldehydes by reaction with ammonia and cyanide ion (the Strecker synthesis)... 

Strecker synthesis (Section 27 4) Method for prepanng amino acids in which the first step is reaction of an aldehyde with ammonia and hydrogen cyanide to give an amino nitnle which IS then hydrolyzed... 

The technology of urea production is highly advanced. The raw materials requited ate ammonia and carbon dioxide. Invariably, urea plants ate located adjacent to ammonia production faciUties which conveniently furnish not only the ammonia but also the carbon dioxide, because carbon dioxide is a by-product of synthesis gas production and purification. The ammonia and carbon dioxide ate fed to a high pressure (up to 30 MPa (300 atm)) reactor at temperatures of about 200°C where ammonium carbamate [111-78-0] CH N202, urea, and water ate formed. 

The Texaco process was first utilized for the production of ammonia synthesis gas from natural gas and oxygen. It was later (1957) appHed to the partial oxidation of heavy fuel oils. This appHcation has had the widest use because it has made possible the production of ammonia and methanol synthesis gases, as well as pure hydrogen, at locations where the lighter hydrocarbons have been unavailable or expensive such as in Maine, Puerto Rico, Brazil, Norway, and Japan. 

Commercial Manufacture of Pyridine. There are two vapor-phase processes used in the industry for the synthesis of pyridines. The first process (eq. 21) uti1i2es formaldehyde and acetaldehyde as a co-feed with ammonia, and the principal products are pyridine (1) and 3-picoline (3). The second process produces only alkylated pyridines as products. 

By-Products. Almost all commercial manufacture of pyridine compounds involves the concomitant manufacture of various side products. Liquid- and vapor-phase synthesis of pyridines from ammonia and aldehydes or ketones produces pyridine or an alkylated pyridine as a primary product, as well as isomeric aLkylpyridines and higher substituted aLkylpyridines, along with their isomers. Furthermore, self-condensation of aldehydes and ketones can produce substituted ben2enes. Condensation of ammonia with the aldehydes can produce certain alkyl or unsaturated nitrile side products. Lasdy, self-condensation of the aldehydes and ketones, perhaps with reduction, can lead to alkanes and alkenes. 

The synthesis which forms the basis of production at Hoffmaim-La Roche (Fig. 5) proceeds via the pyrimidinenitrile [698-29-3] (26) made from malononittile, trimethylorthoformate, ammonia, and acetonitrile (42,43). High pressure catalytic reduction of the nitrile furnishes diamine (16). The overall sequence is short, highly efficient, and generates almost no waste. However, malononittile is a relatively expensive and ha2ardous three-carbon source. 

A synthesis using Hquid ammonia and NaBH has also been described (7). Both methylamine borane [1722-33-4] (CH3)H2N BH, and ethylamine borane... 

The breadth of reactions catalyzed by cobalt compounds is large. Some types of reactions are hydrotreating petroleum (qv), hydrogenation, dehydrogenation, hydrodenitrification, hydrodesulfurization, selective oxidations, ammonoxidations, complete oxidations, hydroformylations, polymerizations, selective decompositions, ammonia (qv) synthesis, and fluorocarbon synthesis (see Fluorine compounds, organic). 

In early times hydrogen cyanide was manufactured from beet sugar residues and recovered from coke oven gas. These methods were replaced by the Castner process in which coke and ammonia were combined with Hquid sodium to form sodium cyanide. If hydrogen cyanide was desired, the sodium cyanide was contacted with an acid, usually sulfuric acid, to Hberate hydrogen cyanide gas, which was condensed for use. This process has since been supplanted by large-scale plants, using catalytic synthesis from ammonia and hydrocarbons. 

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). 

Hydroxyl Group. The OH group of cyanohydrins is subject to displacement with other electronegative groups. Cyanohydrins react with ammonia to yield amino nitriles. This is a step in the Strecker synthesis of amino acids. A one-step synthesis of a-amino acids involves treatment of cyanohydrins with ammonia and ammonium carbonate under pressure. Thus acetone cyanohydrin, when heated at 160°C with ammonia and ammonium carbonate for 6 h, gives a-aminoisobutyric acid [62-57-7] in 86% yield (7). Primary and secondary amines can also be used to displace the hydroxyl group to obtain A/-substituted and Ai,A/-disubstituted a-amino nitriles. The Strecker synthesis can also be appHed to aromatic ketones. Similarly, hydrazine reacts with two molecules of cyanohydrin to give the disubstituted hydrazine. 

In 1959 a new non-protein L-a-amino acid was isolated from the seeds of Acacia willardiana and later from other species of Acacia-, it proved to be l-/3-amino-/3-carboxyethyluracil (977) (59ZPC(316)164). The structure was confirmed by at least four syntheses in the next few years. The most important involves a Shaw synthesis (Section 2.13.3.1.2e) of the acetal (975) and hydrolysis to the aldyhyde (976) followed by a Strecker reaction (potassium cyanide, ammonia and ammonium chloride) to give DL-willardiine (977) after resolution, the L-isomer was identical with natural material (62JCS583). Although not unambiguous, a Principal Synthesis from the ureido acid (978) and ethyl formylacetate is the most direct route (64ZOB407). 

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