Nitriles from acrylonitrile

An important nitrile is acrylonitrile H2C=CHCN It is prepared industrially from propene ammonia and oxygen m the presence of a special catalyst Polymers of acryl omtrile have many applications the most prominent being their use m the preparation of acrylic fibers... 

In the late stage of work up of a sample prepared from acrylonitrile and hydrazine hydrate and stripped of water by a procedure involving dichloromethane, the distillation flask pressurised and burst, shattering the front of the fume cupboard. Previously, slight pressurisation had once been observed. Involving both a nitrile and a hydrazino moiety, this molecule cannot be thermodynamically stable but it has not given previous problems. 

EvenPd(OAc)2 is not effective in catalyzing the cyclopropanation of a,P-unsaturated nitriles by ethyl diazoacetate. Instead, vinyloxazoles 92 are formed from acrylonitrile or methacrylonitrile by carbenoid addition to the CsN bond 143 Diethyl maleate and diethyl fumarate as well as polyketocarbenes are by-products in these reactions the 2-pyrazoline which would result from initial [3 + 2] cycloaddition at the C=C bond and which is the sole product of the uncatalyzed reaction at room temperature, can be avoided completely by very slow addition of the diazoester... 

In the direct ammoxidation of propane over Fe-zeolite catalysts the product mixture consisted of propene, acrylonitrile (AN), acetonitrile (AcN), and carbon oxides. Traces of methane, ethane, ethene and HCN were also detected with selectivity not exceeding 3%. The catalytic performances of the investigated catalysts are summarized in the Table 1. It must be noted that catalytic activity of MTW and silicalite matrix without iron (Fe concentration is lower than 50 ppm) was negligible. The propane conversion was below 1.5 % and no nitriles were detected. It is clearly seen from the Table 1 that the activity and selectivity of catalysts are influenced not only by the content of iron, but also by the zeolite framework structure. Typically, the Fe-MTW zeolites exhibit higher selectivity to propene (even at higher propane conversion than in the case of Fe-silicalite) and substantially lower selectivity to nitriles (both acrylonitrile and acetonitrile). The Fe-silicalite catalyst exhibits acrylonitrile selectivity 31.5 %, whereas the Fe-MTW catalysts with Fe concentration 1400 and 18900 ppm exhibit, at similar propane conversion, the AN selectivity 19.2 and 15.2 %, respectively. On the other hand, Fe-MTW zeolites exhibit higher AN/AcN ratio in comparison with Fe-silicalite catalyst (see Table 1). Fe-MTW-11500 catalyst reveals rather rare behavior. The concentration of Fe ions in the sample is comparable to Fe-sil-12900 catalyst, as well as... 

In basic chemicals, nitrile hydratase and nitrilases have been most successful. Acrylamide from acrylonitrile is now a 30 000 tpy process. In a product tree starting from the addition of HCN to butadiene, nicotinamide (from 3-cyanopyridine, for animal feed), 5-cyanovaleramide (from adiponitrile, for herbicide precursor), and 4-cyanopentanoic acid (from 2-methylglutaronitrile, for l,5-dimethyl-2-piperidone solvent) have been developed. Both the enantioselective addition of HCN to aldehydes with oxynitrilase and the dihydroxylation of substituted benzenes with toluene (or naphthalene) dioxygenase, which are far superior to chemical routes, open up pathways to amino and hydroxy acids, amino alcohols, and diamines in the first case and alkaloids, prostaglandins, and carbohydrate derivatives in the second case. 

Nitrile Hydratase Acrylamide from Acrylonitrile, Nicotinamide from 3-Cyanopyridine, and 5-Cyanovaleramide from Adiponitrile... 

Acrylamide from Acrylonitrile with Nitrile Hydratase... 

Significantly endothermic AHf (1) 147 kJ/mole 2.8 kJ/g. The monomer is sensitive to light, and even when inhibited (with aqueous ammonia) it will polymerise exother-mally at above 200°C [1]. It must never be stored uninhibited, or adjacent to acids or bases [2]. Polymerisation of the monomer in a sealed tube in an oil bath at 110°C led to a violent explosion. It was calculated that the critical condition for runaway thermal explosion was exceeded by a factor of 15 [3]. Runaway polymerisation in a distillation column led to an explosion and fire [4]. Another loss of containment and fire resulted from acrylonitrile polymerisation in a waste solvent tank also containing toluene and peroxides (peroxides are polymerisation initiators) [5]. Use of the nitrile as a reagent in synthesis can lead to condensation of its vapour in unseen parts of the equipment, such as vent-pipes and valves, which may then be obstructed or blocked by polymer [6]. 

Supposing there is no oxygen-based functionality at all, as in the diamine 23 It is not necessary to have a carbonyl group for conjugate addition, in fact a nitrile is much better. So we do FGI on the primary amine and disconnect the secondary amine Et2NH from acrylonitrile 25. The synthesis is to mix those two and reduce 24 catalytically or with LiAlH4-... 

Nitriles are cyanogenic substances — substances that produce cyanide when metabolized. It is likely that nitriles are teratogens because of maternal production of cyanide in pregnant females. A study of the teratogenic effects on rats of saturated nitriles, including acetonitrile, propionitrile, and n-butyronitrile, and of unsaturated nitriles, including acrylonitrile, methacrylonitrile, allylnitrile, m-2-pcntenenitrile, and 2-chloroacrylonitrile, has shown a pattern of abnormal embryos similar to those observed from administration of inorganic cyanide.6... 

The hydration of nitriles to form amides is promoted by metallic catalysts such as nickel and copper,9 and the copper catalyzed hydration has been utilized in an industrial process for the production of acrylamide from acrylonitrile.10 The hydration of... 

Rhodococcus sp. N-774 and Pseudomonas chlororaphis B23 resting cells have been used at industrial scale (as first- and second-generation biocatalysts) for the biological production of acrylamide from acrylonitrile since the 1980s [21]. Currently Rhodococcus rhodochrous J1 is being adopted as a third-generation biocatalyst (Mitsubishi Rayon Co.). The industrial production of nicotinamide from 3-cyanopyridine is also operated with this strain (Lonza AG). However, despite the enormous potentiality of nitrile-hydrolyzing biocatalysts for industrial applications, only a few commercial processes have been realized [22]. 

Mononuclear Active Sites). This reaction has important commercial applications, and nitrile hydratase has been nsed indnstrially for enzymatic production of acrylamide from acrylonitrile. The enzyme contains a mononuclear Fe(II) (or Co(II)) active site, the metal ion being bound in a highly unusual coordination involving two deprotonated peptide amides together with three cysteine side chains (Figure 4). 

The polymer nitrile is a copolymer made from acrylonitrile and butadiene it is used to make automotive hoses and gaskets. Draw the structure of nitrile. (Hint See Table 22.7.)... 

Heat-resistant ABS resins can also be produced by polymerizing styrene with modified nitriles, such as fumaronitrile and maleonitrile. Fumaronitrile can be produced from acrylonitrile (Figure 15.7) in a two-step process involving the addition of hydrogen cyanide followed by oxydehydrogenation over metal oxide catalysts. The compatibility of styrene-co-acrylonitrile-co-fumaronitrile (SANF) terpolymers and SAN has been studied [75]. High-gloss, heat-resistant... 

Other Addition Reactions - The photochemical addition in the gas phase of ammonia to a,P-unsaturated nitriles has been studied. The reactions are carried under conditions where all, or most, of the light is absorbed by the ammonia and this results in N-H bond fission and the production of NH2 radicals. These radicals add to the a-position of the substrate to yield 2-amino-propionitrile from acrylonitrile and analogous products are formed from crotononitrile, methacrylonitrile and 1-cyclohexenecarbonitrile. Additions also occur to but-2-yne nitrile which yields the Z, -isomers of 3-amino-crotononitrile with the E -isomer being predominant. The SET-induced amina-tion (using 1,4-dicyanobenzene as the sensitiser) of alkenylnaphthalene derivatives affords products of addition to both the alkene and the naphthalene skeleton. Suau et al. have examined the irradiation of phthalimide in the presence of low concentrations of hydroxide ion and alkenes. ° The result of this treatment is addition of the phthalimide moiety to the alkene. A SET... 

The degradation of nitriles by nitrilases (EC 3.5.5.1) has been the subject of intense study, especially as it relates to the preparation of the commodity chemical acrylamide. Nitrilases catalyze the hydrolysis of nitriles to the corresponding acid plus ammonia (Figure 1 reaction 5), whereas nitrile hydratases (EC 4.2.1.84) add water to form the amide. Strains such as Rhodococcus rhodo-chrous Jl, Brevibacterium sp., and Pseudomonas chlororaphis have been used to prepare acrylamide from acrylonitrile, which contain the hydratase and not nitrilase activity [12]. A comparison of these strains has been discussed elsewhere [98]. Other uses of nitrilases, however, have primarily been directed at resolution processes to stereoselectively hydrolyze one enantiomer over another or regiose-lectively hydrolyze dinitriles [99-101]. 

There is considerably more information about nitriles from natural gas or petroleum this is to be expected since there are two distinct routes to these substances—from hydrogen cyanide and a hydrocarbon (CeHe + HCN - C H5CN -H H2) and from the pyrolysis of ammonia and hydrocarbons, particularly low-carbon number hydrocarbons, as in CHj + NH3 + CftHe - CeHfcCN 4- 4H2. The latter process is reviewed by Groggins (7), and is extended to imsaturated hydrocarbons. Both acetonitrile and acrylonitrile are so obtained industrially. 

Amides can be made by the enzymatic hydrolysis of nitriles. Nitto Chemical Industry of Japan uses Rhodococcus rhodocrous to prepare acrylamide from acrylonitrile... 

This ester, and also 2,3-dibromopropionitrile (obtained from acrylonitrile under similar conditions), exchange their 3-bromine atoms readily for alkoxyl groups, and the resulting a-bromo-/ -alkoxy esters or nitriles are intermediates in the synthesis of oc-amino- -hydroxy acids — in the above cases for serine.81... 

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