Thermodynamics acrylonitrile production

Examine transition states leading to para and meta adducts 2-methoxybutadiene+acrylonitrile para and meta) as well as the adducts themselves (l-methoxy-4-cyanocyclohexene and l-methoxy-5-cyanocyclohexene). What should the kinetic product be Is this in line with your expectations based on orbital interactions Is this also the thermodynamic product ... 

In the case of vinyl monomers (styrene, acrylonitrile, acrlylamide, isobutylene, etc.) copolymerization is generally spontaneous however, the reaction products are determined by the kinetic constants - a case of interplay between thermodynamic and kinetic factors. 

Thus, in ammonia synthesis, mixed oxide base catalysts allowed new progress towards operating conditions (lower pressure) approaching optimal thermodynamic conditions. Catalytic systems of the same type, with high weight productivity, achieved a decrease of up to 35 per cent in the size of the reactor for the synthesis of acrylonitrile by ammoxidation. Also worth mentioning is the vast development enjoyed as catalysis by artificial zeolites (molecular sieves). Their use as a precious metal support, or as a substitute for conventional silico-aluminaies. led to catalytic systems with much higher activity and selectivity in aromatic hydrocarbon conversion processes (xylene isomerization, toluene dismutation), in benzene alkylation, and even in the oxychlorination of ethane to vinyl chloride. 

An examination of reported reactivity ratios (Table 6) shows that the behaviour rj > 1, r2 1 or vice versa is a common feature of anionic copolymerization. Only in copolymerizations involving the monomers 1,1-diphenylethylene and stilbene, which cannot homopolymerize, do we find <1, r2 <1 [212—215], and hence the alternating tendency so characteristic of many free radical initiated copolymerizations. Normally one monomer is much more reactive to either type of active centre in the order acrylonitrile > methylmethacrylate > styrene > butadiene > isoprene. This is the order of electron affinities of the monomers as measured polarographically in polar solvents [216, 217]. In other words, the reactivity correlates well with the overall thermodynamic stability of the product. Variations of reactivity ratio occur with different solvents and counter-ions but the gross order is predictable. 

Lithiation of 3-(l-pyrrolidinyl)acrylonitrile with LiN(Pr-i)2, provides the kinetic product below — 105°C at higher T, isomerization to the thermodynamic product oc-... 

Stull, Westrum, and Sinke devote a chapter to the discussion of the applications of thermodynamics to industrial problems. Subjects covered include the petroleum industry, chemicals from methane, styrene manufacture, acrylonitrile and vinyl chloride syntheses, methanol synthesis, formaldehyde production from methanol, acetic acid manufacture, the Gatterman-Koch reaction, and catalyst selection. 

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