Synthesis reactions acrylonitrile

V-Sb-oxide based catalysts show interesting catal)dic properties in the direct synthesis of acrylonitrile from propane [1,2], a new alternative option to the commercial process starting from propylene. However, further improvement of the selectivity to acrylonitrile would strengthen interest in the process. Optimization of the behavior of Sb-V-oxide catalysts requires a thorough analysis of the relationship between structural/surface characteristics and catalytic properties. Various studies have been reported on the analysis of this relationship [3-8] and on the reaction kinetics [9,10], but little attention has been given to the study of the surface reactivity of V-Sb-oxide in the transformation of possible intermediates and on the identification of the sxirface mechanism of reaction. 

Co-adsorption experiments show a complex role of the nature and concentration of chemisorbed ammonia species. Ammonia is not only one of the reactants for the synthesis of acrylonitrile, but also reaction with Br()>nsted sites inhibits their reactivity. In particular, IR experiments show that two pathways of reaction are possible from chemisorbed propylene (i) to acetone via isopropoxylate intermediate or (ii) to acrolein via allyl alcoholate intermediate. The first reaction occurs preferentially at lower temperatures and in the presence of hydroxyl groups. When their reactivity is blocked by the faster reaction with ammonia, the second pathway of reaction becomes preferential. The first pathway of reaction is responsible for a degradative pathway, because acetone further transform to an acetate species with carbon chain breakage. Ammonia as NH4 reacts faster with acrylate species (formed by transformation of the acrolein intermediate) to give an acrylamide intermediate. At higher temperatures the amide may be transformed to acrylonitrile, but when Brreform ammonia and free, weakly bonded, acrylic acid. The latter easily decarboxylate forming carbon oxides. 

As an exercise, the reader may verify all the stated properties of these matrices. Let us consider the synthesis of acrylonitrile from propene, ammonia and oxygen. The overall reaction is ... 

Hur et al. (252,277,278) reported the use of alkali metal-doped MgO to catalyze the synthesis of acrylonitrile and propionitrile (278). Acrylonitrile is an important chemical, especially in the polymer industry it is generally synthesized by the ammoxidation of propene catalyzed by multicomponent bismuth molybdates (279). An alternative method of synthesis of acrylonitrile is the reaction between methanol and acetonitrile (Scheme 42). 

Similar synthesis with acrylonitrile has been described by the following reaction scheme ... 

This reaction was once regarded as an important industrial process, since it afforded a straightforward synthesis of acrylonitrile from acetylene ... 

Copper chloride complexes can be used as catalysts in a number of organic reactions. Examples include the Wacker process, which is the oxidization of ethylene to acetaldehyde by oxygen and aqueous Cu and Pd precatalysts (or, alternatively using iron catalysts) plus the synthesis of acrylonitrile from acetylene and hydrogen cyanide using CuCl. Cuprous chloride has also been used as a desulfiuizmg and... 

Whole-cell MBR have been utilized in a number of biochemical synthesis reactions. An example used industrially, is growth hormone biosynthesis by the bacteria E. coli (Le-goux et al [4.25]). Using the MBR allows the synthesis of this hormone free from pathogens, like those causing the Creutzfeld-Jacob disease, for example. Other industrial examples include the synthesis of homochiral cyanohydrins (Bauer et al. [4.26]), the production of L-aspartic acid [4.16, 4.27], and the biotransformation of acrylonitrile to acrylamide... 

These results clearly indicate that Sb -oxide, stabilized at the surface of vanadium-antimonate, is responsible for the selective synthesis of acrylonitrile from the intermediate propylene in agreement with previous suggestions [16], and that vanadium catalyzes the leoxidation of reduced antimony, as well as plays other roles in the mechanism of oxidative dehydrogmia-tion of propane to propylene and in the side reaction of NH3 oxidation to N2 (see above). 

The drawbacks of using a turbulent bed for partial oxidization reactions are backmixing and low throughput. A wide distribution in solid residence time also makes controlling the reaction difficult. With new developments in catalysts, synthesis of acrylonitrile can be completed in a few seconds and suggests that... 

Wei F, Lai ZP, Jin Y, Yu ZQ. A CFB reactor model for the synthesis of acrylonitrile. Proceedings of Asian-Pacific Conference on Chemical Reaction Engineering, Beijing, China, 1996, pp 625-630. 

Unsaturated nitriles are formed by the reaction of ethylene or propylene with Pd(CN)2[252]. The synthesis of unsaturated nitriles by a gas-phase reaction of alkenes. HCN, and oxygen was carried out by use of a Pd catalyst supported on active carbon. Acrylonitrile is formed from ethylene. Methacrylonitrile and crotononitrile are obtained from propylene[253]. Vinyl chloride is obtained in a high yield from ethylene and PdCl2 using highly polar solvents such as DMF. The reaction can be made catalytic by the use of chloranil[254]. 

Ring Synthesis From Nonheterocyclic Compounds. These methods may be further classified based on the number of bonds formed during the pyridine ring formation. Synthesis of a-picoline (2) from 5-oxohexanenitrile is a one-bond formation reaction (eq. 16) (49). The nitrile is obtained by reaction between acetone and acrylonitrile (50). If both reaction steps are considered together, the synthesis must be considered a two-bond forming one, ie, formation of (2) from acetone and acrylonitrile in a single step comes under the category of two-bond formation reaction. 

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). 

A major type of reaction in this class is the cyclization of 4-amino- or 4-halo-pyrimidines carrying 5-cyanoethyl or 5-ethoxycarbonylethyl groups, which cyclize to 7-amino or 7-oxo derivatives of 5,6-dihydropyrido[2,3- f]pyrimidine, e.g. (131)->(63). The intermediates may sometimes be prepared by reaction of 4(6)-aminopyrimidines with acrylonitrile, or even via a pyrimidine ring synthesis from an amidine and a cyanoacetic ester or malononitrile derivative, e.g. (132) -> (133) (7lJOC2 85, 72BCJ1127). 

Acrylic acid, -(3-benzo[f>]thienyl)-a -mercapto-reaction with iodine, 4, 764 Acrylic acid, o -cyano-y3-(2-thienyl)-ring opening, 4, 807 Acrylic acid, -formyl-in pyridazinone synthesis, 3, 46 Acrylic acid, furyl-rotamers, 4, 545 synthesis, 4, 658 Acrylic acid, 2-hydroxybenzoyl-chroman-4-one synthesis from, 3, 850 Acrylic acid, 5-(l-propynyl)-2-thienyl-methyl ester occurrence, 4, 909 Acrylonitrile... 

Imidazo[4,5-c]pyridine-2(3f7)-thione, 1-methyl-reactions with acrylonitrile, 5, 620 Imidazo[l,2-a]pyridine-2(3H)-thiones synthesis, 5, 632... 

Kondrat eva pyridine synthesis. This methodology to pyridine rings continues to be applied in total synthesis. An approach to the antitumor compound ellipticine 34 ° makes use of a Diels-Alder reaction of acrylonitrile and oxazole 32 to form pyridiyl derivative 33. Addition of methyllithium and hydrolysis transforms 33 into 34. 

The side-chain cyanoethylation of alkyl thienyl ketones with acrylonitrile has been studied " and used for the preparation of 8-oxonitriles and S-oxoacids. Aminomethylation (Mannich reaction) of 2-acetylthiophene followed by steam distillation yielded 50% of 2-thienyl vinyl ketone, and has also been used for the synthesis of compounds of biological interest. ... 

The ability of 1,2 (or l,6)-dihydropyridines to undergo a Diels-Alder reaction with dienophiles such as methyl vinyl ketone, methyl acrylate, and acrylonitrile has been utilized in the synthesis of polyfunctional isoquinuclidine as a key intermediate in the synthesis of aspidosperma- and iboga-type alkaloids (66JA3099). 

The imidazoline denvative cibeiuoline (64) is a class I antiarrhythmic agent which has undergone clinical trials in the United States with apparently satisfactory results It is synthesized by diphenylcyclopropananon of acrylonitrile by thermal carbene generation from diphenyldiazo methane (62) to give 1 cyano 2,2 diphenylc>clopropane (63) Reaction of this with ethylenedia mine tosylate completes the synthesis of ciben/oline (64) [221... 

When the polymer was prepared by the suspension polymerization technique, the product was crosslinked beads of unusually uniform size (see Fig. 16 for SEM picture of the beads) with hydrophobic surface characteristics. This shows that cardanyl acrylate/methacry-late can be used as comonomers-cum-cross-linking agents in vinyl polymerizations. This further gives rise to more opportunities to prepare polymer supports for synthesis particularly for experiments in solid-state peptide synthesis. Polymer supports based on activated acrylates have recently been reported to be useful in supported organic reactions, metal ion separation, etc. [198,199]. Copolymers are expected to give better performance and, hence, coplymers of CA and CM A with methyl methacrylate (MMA), styrene (St), and acrylonitrile (AN) were prepared and characterized [196,197]. 

Molybdenum, tris(phenylenedithio)-structure, 1,63 Molybdenum alkoxides physical properties, 2,346 synthesis, 2,339 Molybdenum blue liquid-liquid extraction, 1,548 Molybdenum cofactor, 6,657 Molybdenum complexes acrylonitrile, 2,263 alkoxides, 3,1307 alkoxy carbonyl reactions, 2,355 alkyl, 3,1307 alkyl alkoxy reactions, 2,358 alkyl peroxides oxidation catalyses, 6,342 allyl, 3,1306... 

---