Acrylonitrile, 2- addition reactions

Another type of polyol often used in the manufacture of flexible polyurethane foams contains a dispersed soHd phase of organic chemical particles (234—236). The continuous phase is one of the polyols described above for either slab or molded foam as required. The dispersed phase reacts in the polyol using an addition reaction with styrene and acrylonitrile monomers in one type or a coupling reaction with an amine such as hydrazine and isocyanate in another. The soHds content ranges from about 21% with either system to nearly 40% in the styrene—acrylonitrile system. The dispersed soHds confer increased load bearing and in the case of flexible molded foams also act as a ceU opener. 

Also, Michael addition reactions occur between Ai-acylaminomalonic acid esters and unsaturated compounds, ie, acrolein [107-02-8] acrylonitrile [107-13-1y, acryhc acid esters, and amino acids result from hydrolysis of the addition products. 

The ratio of the two diastereomeric products 190 and 191 was found to depend on the reaction temperature and reaction time. The addition of acrolein or methyl vinyl ketone proceeded smoothly, but in the case of methylacrylate or acrylonitrile the reaction did not proceed under the same conditions (EtsN THF 30°C). An accompanying AMI calculation of these Q ,/3-unsaturated compounds [LUMOs for acrolein, -0.13877 for methyl vinyl ketone, -0.06805 (s-trans) for methyl acrylate, -0.01413 (s-tmns) for acrylonitrile, 0.04971] suggested the low reactivity of methyl acrylate and acrylonitrile toward the Michael reaction (99H1321). 

Enamines react with acceptor-substituted alkenes (Michael acceptors) in a conjugate addition reaction for example with o ,/3-unsaturated carbonyl compounds or nitriles such as acrylonitrile 8. With respect to the acceptor-substituted alkene the reaction is similar to a Michael addition ... 

Absolute rate constants for addition reactions of cyanoalkyl radicals are significantly lower than for unsubstituted alkyl radicals falling in the range 103-104 M V1.341 The relative reactivity data demonstrate that they possess some electrophilic character. The more electron-rich VAc is very much less reactive than the electron-deficient AN or MA. The relative reactivity of styrene and acrylonitrile towards cyanoisopropyl radicals would seem to show a remarkable temperature dependence that must, from the data shown (Table 3.6), be attributed to a variation in the reactivity of acrylonitrile with temperature and/or other conditions. 

Waters61 have measured relative rates of p-toluenesulfonyl radical addition to substituted styrenes, deducing from the value of p + = — 0.50 in the Hammett plot that the sulfonyl radical has an electrophilic character (equation 21). Further indications that sulfonyl radicals are strongly electrophilic have been obtained by Takahara and coworkers62, who measured relative reactivities for the addition reactions of benzenesulfonyl radicals to various vinyl monomers and plotted rate constants versus Hammett s Alfrey-Price s e values these relative rates are spread over a wide range, for example, acrylonitrile (0.006), methyl methacrylate (0.08), styrene (1.00) and a-methylstyrene (3.21). The relative rates for the addition reaction of p-methylstyrene to styrene towards methane- and p-substituted benzenesulfonyl radicals are almost the same in accord with their type structure discussed earlier in this chapter. 

There is a possibiUty that (hydroxymethyl)phosphines might be catalyzing hydration of activated olefinic moieties in lignin. The Michael addition reaction shown in eq. (6a) is catalyzed by 5% THP in water at ambient conditions, with 70% conversion of the acrylonitrile no such reaction is seen with aciyhc acid or the methyl ester, but analogous hydromethoxylation of these compounds is seen in MeOH (42) (eq. (6b), R = H or Me). There is a report on similar catalytic use of tiialkylphosphines, which, like THP, are strong nucleophiles (43). 

Malacria has reported the use of epoxysilanes for intermolecular addition reactions to acrylates, acrylonitrile and vinylsulfones [56]. 

The dependence of relative rates in radical addition reactions on the nucleophilicity of the attacking radical has also been demonstrated by Minisci and coworkers (Table 7)17. The evaluation of relative rate constants was in this case based on the product analysis in reactions, in which substituted alkyl radicals were first generated by oxidative decomposition of diacyl peroxides, then added to a mixture of two alkenes, one of them the diene. The final products were obtained by oxidation of the intermediate allyl radicals to cations which were trapped with methanol. The data for the acrylonitrile-butadiene... 

A Michael-type addition reaction of phosphine generated from red phosphorus in concentrated aqueous KOH solution has been noted to provide moderate isolable yields of pure organophosphorus products.27 For example, tris-(2-cyanoethyl)phosphine is produced in 45% isolable yield from acrylonitrile, and tris-(2-[y-pyridyl]ethyl) phosphine oxide is isolated in 40% yield from 4-vinylpyridine under these conditions. Excellent yields of the tertiary phosphine oxide, tris-(2-cyanoethyl)phosphine oxide, have been reported using white phosphorus in absolute ethanol with KOH at ice/salt-bath temperatures.28 A variety of solvent systems were examined for this reaction involving a Michael-type addition to acrylonitrile. Similarly, tris-(Z-styryl)phosphine is produced from phenylacetylene under these conditions in 55% isolated yield. It is noteworthy that this last cited reaction involves stereospecific syn- addition of the phosphine to the alkyne. 

Acrylonitrile, polymerization, 120 Activity of phase-transfer catalysts Sjj2 reactions, 170-175 weak-nucleophile Sj.Ar reactions, 175-182 Acyltetracarbonyl cobalt compound, cleavage in the carboxyalkylation of alkyl halides, 150 Addition reactions, Michael, catalytic asymmetric, 69,70f... 

Neither of these methods is used today. Around 1970 the industry switched from C2 raw materials and classical organic chemical addition reactions to the ammoxidation of propylene. Now all acrylonitrile is made by this procedure, which involves reaction of propylene, ammonia, and oxygen at 400-450°C and 0.5-2 atm in a fluidized bed Bi203 nMo03 catalyst. The yield is approximately 70%. 

Acrylonitrile polymerization is similarly complicated by addition reactions of the initiator and/or propagating nucleophiles with the nitrile group [Berger and Adler, 1986 Tsvetanov, 1979 Vankerckhoven and Van Beylen, 1978]. 

Thieno[3,4-c]pyridines undergo an addition reaction with acrylonitrile followed by elimination of hydrogen sulfide to afford a mercaptoisoquinoline product (Equation 2) <2002CHE1342>. 

Methacrylonitrile (1) differs from 2 only in that it has a methyl (CH3) group on the a-carbon atom. It too is widely used in the preparation of homopolymers and copolymers, elastomers, and plastics and as a chemical intermediate in the preparation of acids, amides, amines, esters, and other nitriles. In a study conducted by the NTP in which 1 was administered orally to mice for 2 years, there was no evidence that it caused cancer, although other less serious toxic effects were noted [27]. Because 1 does not cause cancer, but undergoes many of the same nucleophilic addition reactions as 2 at the (3-carbon, it is sometimes used as a safer commercial replacement for 2, such as in the manufacture of an acrylonitrile-butadiene-styrene-like polymer that provides improved barrier properties to gases such as carbon dioxide in carbonated beverage containers. 

Other addition reactions Additions involving carbon Copper(I) chloride, 85 Lithium bis(dimethylphenyl-silyl)cuprate, 161 Manganese(III) acetate, 171 Mercury(II) chloride, 175 2-(Phenylseleno)acrylonitrile, 244 Threophos, 298 Additions involving nitrogen Benzeneselenenyl halides, 26 Additions involving oxygen Bis(Tj5-cyclooctadienyl)ruthe-nium(II), 35... 

Nucleophilic addition reactions of para-substituted benzylamines (XC6H4CH2NH2) to a-phenyl-/9-thiophenylacrylonitriles [Y(C4SH2)CH=C(CN)C6H4Y/] have been studied in acetonitrile at 25.0, 30.0, and 35.0 °C. The reactions apparently take place in a single step in which the C/ -N bond formation and proton transfer to C of a-phenyl-/3-thiophenyl acrylonitriles occur concurrently with a four-membered cyclic transition structure. These mechanistic conclusions were deduced from the following ... 

The polarisation produced by co-ordination to the metal may be transmitted through a conjugated system. Michael addition reactions of nucleophiles to TV-bonded acrylonitrile are known, and provide a convenient method for the preparation of derivatives. A wide range of nucleophiles may be used in these conjugate additions. For example, the anion of nitromethane (generated in situ) reacts with the ruthenium(m) complex [Ru(NH3)5N=CCH=CH2)]3+, 4.6, to yield a complex of 4-nitrobutyronitrile (Fig. 4-18). 

Unsaturated vinyl esters for use in polymerization reactions are made by the esterification of olefins. The most important ones are vinyl esters vinyl acetate, vinyl chloride, acrylonitrile, and vinyl fluoride. The addition reaction may be carried out in either the liquid, vapor, or mixed phases, depending on the properties of the acid. Care must be taken to reduce the polymerization of the vinyl ester produced. 

An acyl radical is also nucleophilic. For example, the rate constant of (CH3)3CC0 (te/T-butylcarbonyl radical, pivaloyl radical) with acrylonitrile is 4.8 X 105 M-1 s-1 (25 °C), and so its addition reaction proceeds effectively [72]. 

Tretyakov and Filimonov (219) describe a coordinative interaction between benzonitrile and aprotic sites on magnesium oxide, and Zecchina et al. (256) came to the same conclusion for the adsorption of propionitrile, benzonitrile, and acrylonitrile on a chromia-silica catalyst. Chapman and Hair (257) observed an additional chemical transformation of benzonitrile on alumina-containing surfaces, which they describe as an oxidation. Knozinger and Krietenbrink (255) have shown that acetonitrile is hydrolyzed on alumina by basic OH- ions, even at temperatures below 100°C. This reaction may be described as shown in Scheme 2. The surface acetamide (V) is subsequently transformed into a surface acetate at higher temperatures. Additional reactions on alumina are a dissociative adsorption and polymerizations (255) analogous to those observed for hydrogen cyanide by Low and Ramamurthy (258), and a dissociative adsorption. Thus, acetonitrile must certainly be refused as a probe molecule and specific poison. 

Base-catalyzed The parent phenol complex 85 undergoes a variety of base-catalyzed Michael addition reactions at room temperature to generate 4H-phenol complexes in yields in the range 79-99 % (Table 14) [29]. Michael additions with MVK, methyl acrylate, acrylonitrile, N-methylmaleimide, cydopentenone, and crotonaldehyde (entries 1-6, respectively) proceed with high regio- and stereocontrol. Demetalation and isolation of the dienone is typically accompanied by tautomerization to the aromatic substitution product. 

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