Acetylene acrylonitrile

BROM (German) (7726-95-6) A powerful oxidizer. Violent reaction with reducing agents. Can cause fire and explosions in contact with organic or other readily oxidizable materials. Contact with water or steam forms hydrobromic acid and oxygen. Contact with aqueous ammonia, acetaldehyde, acetylene, acrylonitrile, hydrogen may cause violent reactions. Anhydrous material reacts violently with aluminum, titanium, mercury, or potassium wet material reacts with other metals. Incompatible with many materials, including alcohols. 

Hazardous Decomp. Prods. Heated to decomp., emits toxic fumes of NOx Uses Plasticizer, emulsifier, and coalescent for acrylic latexes, styrene-acrylic floor polishes solvent for polymers, insecticides, veterinary medicine selective solvent (acetylene, acrylonitrile prod.) process solvent (pharmaceuticals) specialty inks monomer for nylon-4 pharmaceutical solubilizer, intermediate synthesis of piracetam treatment of cerebral distress... 

Acetone Acetylene Acrylonitrile Allyl alcohol Alum... 

Acetaldehyde Acetic acid 75%, 50°C Acetic anhydride Acetone Acetylene Acrylonitrile Adipic acid, aqueous Alum, aqueous Aluminum chloride Aluminum fluoride Aluminum sulfate Ammonia... 

Ethyne is the starting point for the manufacture of a wide range of chemicals, amongst which the most important are acrylonitrile, vinyl chloride, vinyl acetate, ethanal, ethanoic acid, tri- and perchloro-ethylene, neoprene and polyvinyl alcohol. Processes such as vinylation, ethinylation, carbonylation, oligomerization and Reppe processes offer the possibility of producing various organic chemicals cheaply. Used in oxy-acetylene welding. 

Donor substituents on the vinyl group further enhance reactivity towards electrophilic dienophiles. Equations 8.6 and 8.7 illustrate the use of such functionalized vinylpyrroles in indole synthesis[2,3]. In both of these examples, the use of acetyleneic dienophiles leads to fully aromatic products. Evidently this must occur as the result of oxidation by atmospheric oxygen. With vinylpyrrole 8.6A, adducts were also isolated from dienophiles such as methyl acrylate, dimethyl maleate, dimethyl fumarate, acrolein, acrylonitrile, maleic anhydride, W-methylmaleimide and naphthoquinone. These tetrahydroindole adducts could be aromatized with DDQ, although the overall yields were modest[3]. 

Addition of HCN to unsaturated compounds is often the easiest and most economical method of making organonitnles. An early synthesis of acrylonitrile involved the addition of HCN to acetylene. The addition of HCN to aldehydes and ketones is readily accompHshed with simple base catalysis, as is the addition of HCN to activated olefins (Michael addition). However, the addition of HCN to unactivated olefins and the regioselective addition to dienes is best accompHshed with a transition-metal catalyst, as illustrated by DuPont s adiponitrile process (6—9). 

Because of its relatively high, price, there have been continuing efforts to replace acetylene in its major appHcations with cheaper raw materials. Such efforts have been successful, particularly in the United States, where ethylene has displaced acetylene as raw material for acetaldehyde, acetic acid, vinyl acetate, and chlorinated solvents. Only a few percent of U.S. vinyl chloride production is still based on acetylene. Propjiene has replaced acetylene as feed for acrylates and acrylonitrile. Even some recent production of traditional Reppe acetylene chemicals, such as butanediol and butyrolactone, is based on new raw materials. 

Acrylic Acid, Acrylates, and Acrylonitrile. Acryhc acid [79-10-7], and acrylates were once prepared by reaction of acetylene and... 

In the presence of such catalysts as a solution of cuprous and ammonium chlorides, hydrogen cyanide adds to acetylene to give acrylonitrile... 

Calcium carbide has been used in steel production to lower sulfur emissions when coke with high sulfur content is used. The principal use of carbide remains hydrolysis for acetylene (C2H2) production. Acetylene is widely used as a welding gas, and is also a versatile intermediate for the synthesis of many organic chemicals. Approximately 450,000 t of acetylene were used aimuaHy in the early 1960s for the production of such chemicals as acrylonitrile, acrylates, chlorinated solvents, chloroprene, vinyl acetate, and vinyl chloride. Since then, petroleum-derived olefins have replaced acetylene in these uses. 

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). 

Hydrogen cyanide adds to an olefinic double bond most readily when an adjacent activating group is present in the molecule, eg, carbonyl or cyano groups. In these cases, a Michael addition proceeds readily under basic catalysis, as with acrylonitrile (qv) to yield succinonitnle [110-61-2], C4H4N2, iu high yield (13). Formation of acrylonitrile by addition across the acetylenic bond can be accompHshed under catalytic conditions (see Acetylene-DERIVED chemicals). 

The first U.S. plant for acrylonitrile manufacture used an ethylene cyanohydrin feedstock. This was the primary route for acrylonitrile manufacture until the acetylene-based process began to replace it in 1953 (40). Maximum use of ethylene cyanohydrin to produce acrylonitrile occurred in 1963. Acrylonitrile (qv) has not been produced by this route since 1970. 

Reaction of coke with calcium oxide gives calcium carbide, which on treatment with water produces acetylene. This was for many years an important starting point for the production of acrylonitrile, vinyl chloride, vinyl acetate and other vinyl monomers. Furthermore, during World War II, Reppe developed routes for many other monomers although these were not viable under normal economic conditions. 

With each succeeding year in the 1950s and 1960s there was a swing away from coal and vegetable sources of raw materials towards petroleum. Today such products as terephthalic acid, styrene, benzene, formaldehyde, vinyl acetate and acrylonitrile are produced from petroleum sources. Large industrial concerns that had been built on acetylene chemistry became based on petrochemicals whilst coal tar is no longer an indispensable source of aromatics. 

Acrylonitrile can be manufactured by reacting acetylene with hydrogen cyanide ... 

Ethylene is produced in quantity using acetylene or propylene as feedstock to make a large number of products (Figure 7.2-3) such as acetaldehyde, acrylonitrile, acetic acid, and acetic anhydride. These are made generally from acetylene which is made from calcium carbide. 

Although hexafluoro-l,3-butadiene is better known for its [2+2] reactions, its Diels-Alder reactions, particularly with electron-deficient alkenes such as acrylonitrile and perfluoropropene, are not unknown [9] The first report of a Diels-Alder reaction is with an acetylenic dienophile Although the major product of Us reaction with phenylacetylene is its [2+2] adduct, a 3 5% yield of products of a Diels-Alder reaction is also observed [123] (equation 103)... 

For the ordinary Diels-Alder reaction the dienophile preferentially is of the electron-poor type electron-withdrawing substituents have a rate enhancing effect. Ethylene and simple alkenes are less reactive. Substituent Z in 2 can be e.g. CHO, COR, COOH, COOR, CN, Ar, NO2, halogen, C=C. Good dienophiles are for example maleic anhydride, acrolein, acrylonitrile, dehydrobenzene, tetracya-noethylene (TCNE), acetylene dicarboxylic esters. The diene preferentially is of the electron-rich type thus it should not bear an electron-withdrawing substituent. 

Acetylene, clathrate in hydroquinone, 7 hydrate thermodynamic data and lattice constants, 8 Acrylamides, polymerization of, 181 Acrylonitrile, 155 Activity coefficients, 125... 

Acrylonitrile Propanenitrile Pyrazines Pyrroles Acetylene Maleic acid Maleic anhydride Succinic anhydride... 

An example of the way in which process competition works in the manufacture of plastics is the story of acrylonitrile. The first process for the production of this plastic was based upon the reaction between hydrogen cyanide and acetylene, both hard to handle, poisonous, and explosive chemicals. The raw material costs were relatively low as compared to materials for other monomers, but the plant investment and manufacturing costs were too high. As a result, originally acrylonitrile monomer (1950s) sold for about 30 cents per pound and the future of the material looked dim as other plastics such as polyethylene became available at much lower prices due to their lower production costs. 

The second principle was the great defensive strength of an established, capital intensive procedure. In the overall process for making acrylonitrile via acetylene, very big plants were needed for making the acetylene either by partial oxidation of methane or from carbide furnaces. Manufacture of HCN from methane involved further expense ... 

A = Acrylonitrile B = Benzoquinone C = Naphthoquinone D = 5,8-Quinolinequinone E = Methyl vinyl ketone F = Dimethyl acetylene dicarboxylate G = Methyl acrylate ... 

Until the 1960s, acrylonitrile was, like vinyl acetate, made from acetylene (by reaction with hydrogen cyanide), but research on catalysts in the 1950s led to the much less costly route shown above. 

Because of its high chemical reactivity, acetylene has found wide use in synthesis of vinyl chloride, vinyl acetate, acrylonitrile, vinyl ethers, vinyl acetylene, trichloro- and tetrachloro-ethylene etc., in oxyacetylene cutting and welding, and as a fuel for atomic absorption instruments. 

Because of the relative instabihty of many trimethylsilyl nitronates 1036, 1037, they should be reacted in situ with olefins 1053 [103-105] or acetylenes [127] to generate the isooxazolidines 1054 [103-105, 107-117, 119-133] or isoxazoles [127] (Scheme 7.37) The isoxazolidines 1054 with R2=H readily ehminate trimethylsilanol 4 in the presence of acids such as TsOH to form the isoxazolines 1055 in high yields [104, 105] (Scheme 7.37 cf. also the cycloadditions with acrylonitrile in Scheme 7.42). 

ETHYLENE GLYCOL ETHYL MERCAPTAN DIMETHYL SULPHIDE ETHYL AMINE DIMETHYL AMIDE MONOETHANOLAMINE ETHYLENEDIAMINE ACRYLONITRILE PROPADIENE METHYL ACETYLENE ACROLEIN ACRYLIC ACID VINYL FORMATE ALLYL CHLORIDE 1 2 3-TRICHLOROPROPANE PROPIONITRILE CYCLOPROPANE PROPYLENE 1 2-DICHLOROPROPANE ACETONE ALLYL ALCOHOL PROPIONALDEHYDE PROPYLENE OXIDE VINYL METHYL ETHER PROPIONIC ACID ETHYL FORMATE METHYL ACETATE PROPYL CHLORIDE ISOPROPYL CHLORIDE PROPANE... 

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