Oxidation of crotonaldehyde

The commercial method consists in the oxidation of crotonaldehyde, which is itself prepared from acetaldehyde (see Section 111,141) ... 

Finally, let us recall that a similar mechanism may explain the slow thermal oxidation of crotonaldehyde at about 150-200°C. ... 

CH=CHCOOH. A white crystalline solid prepared by the oxidation of crotonaldehyde. It forms copolymers with vinyl acetate, used as hot-melt adhesives. Esters of crotonic acid are used as plasticizers for acrylic and cellulosic plastics (See image), o... 

Kinetics of the oxidation of crotonaldehyde by tetraethylammonium chlorochromate have been measured in 50/50 aqueous acetic acid, including derivation of activation parameters. ... 

The choice of raw material can be dictated by other reasons as well. Although there is no evidence of crotonaldehyde being used as a feed commercially, it has been reported that during World War II, I. G. Farbenindustrie made MA by the oxidation of crotonaldehyde 1. This conclusion was probably based on the patent activity by that company before the war, " although no evidence to this effect was found. " ... 

Mac Millan and coworkers used a multicatalytic system composed of the imi-dazolidinone 8 and d- or L-proline for the diamination and the amino oxidation of crotonaldehyde [16]. Similar to the aryl- and alkylamination, the syn or the anti diastereomers were obtained in a stereoselective manner by using the catalyst combination containing l- or D-proline (dr up to 1/17) (Scheme 12.15). The cascade catalysis provided enantioselective access to differentially protected 1,2-diaminated products 34 and 35 by the use of a silyloxycarbamate in conjunction with dibenzyla-zodicarboxylate (yield 84-87%, ee 99%). A similar amine nucleophile was employed in a cascade catalysis sequence with nitrosobenzene to afford the 3-amino-2-hydroxy alcohols (yield 71-74%, ee 99%). 

Normal butyl alcohol, propyl carbinol, n-butanol, 1-buianol, CH3CH2CH2CH2OH. B.p. 117 C. Manufactured by reduction of crotonaldehyde (2-buienal) with H2 and a metallic catalyst. Forms esters with acids and is oxidized first to butanal and then to butanoic acid. U.S. production 1978 300 000 tonnes. 

Union Carbide abandoned the ketene—crotonaldehyde route in 1953 in favor of the oxidation of 2,4-hexadienal made by acetaldehyde condensation. A silver compound used as the catalyst prevented peroxidation of the ethylenic bonds (39,40). Thein plant operated until 1970. 

Preparing sorbic acid by reaction of crotonaldehyde and acetone followed by oxidation of the crotonyUdenacetone is of interest in the former Soviet Union (41,42) ... 

It is often said that the property of acidity is manifest only in the presence of a base, and NMR studies of probe molecules became common following studies of amines by Ellis [4] and Maciel [5, 6] and phosphines by Lunsford [7] in the early to mid 80s. More recently, the maturation of variable temperature MAS NMR has permitted the study of reactive probe molecules which are revealing not only in themselves but also in the intermediates and products that they form on the solid acid. We carried out detailed studies of aldol reactions in zeolites beginning with the early 1993 report of the synthesis of crotonaldehyde from acetaldehyde in HZSM-5 [8] and continuing through investigations of acetone, cyclopentanone [9] and propanal [10], The formation of mesityl oxide 1, from dimerization and dehydration of... 

Sorbic acid has been prepared from crotonaldehyde 1 5 or aldol6 and malonic acid in pyridine solution by hydrogen peroxide oxidation of the condensation product of crotonaldehyde and pyruvic acid 7 and by the action of alkali on 3-hydroxy-4-hexenoic acid,8 9 /3,5-disulfo-w-caproic acid,10 and parasorbic acid.1112... 

Maleic anhydride (2,5-furandione) is obtained as a by-product in the production of phthalic anhydride and by the vapor phase oxidation of butylene or crotonaldehyde. It is also obtained by the dehydration of maleic acid and by the oxidation of benzene. Maleic anhydride is used for the production of unsaturated polyester resin. This reactant, like most reactants, is fairly toxic and should be treated as such. 

The oxidation of substituted /3-benzoylpropionic acids by PFC follows the Hammett relation with a negative reaction constant. A possible mechanism for the oxidation has been discussed.5 The oxidation of maleic, fumaric, crotonic, and cinnamic acids by PCC is of first order with respect to PCC and the acid. The oxidation rate in 19 organic solvents has been analysed by Kamlet s and Swain s multiparametric equations. A mechanism involving a three-centre transition state has been postulated.6 The relative reactivity of bishomoallylic tertiary alcohols toward PCC, to yield substituted THF products via the tethered chromate ester, is dependent only on the number of alkyl groups. This observation suggests a symmetrical transition state in this intramolecular Cr(VI)-alkene reaction.7 Mechanisms have been proposed for the oxidation of 2-nitrobenzaldehyde with PBC8 and of crotonaldehyde with tetraethylammonium chlorochromate.9... 

The gas phase photooxidation of crotonaldehyde has been studied by Blacet and Volman.21 The product is crotonic acid, which condenses out of the system as soon as it is formed. The quantum yield of oxidation was found to increase steadily over the 3660-2380 A. wavelength range. At constant aldehyde pressure, the quantum yield was independent of oxygen pressure at 3130 and 2804 A. At 2537 A., however, the quantum yield increased rapidly with the oxygen pressure and a chain mechanism is likely. Addition of nitrogen at 2537 A. caused a marked decrease in the quantum yield indicating that excited molecules are involved. 

Figure 22.7. The major DNA lesions of the lipid peroxidation products. (A) DNA lesions produced by malondialdehyde. Mi denotes the monomeric form of malondialdehyde. Malo-ndialdehyde can polymerize to form dimers and trimers that can also react with DNA. The resulting lesions are designated as M2 and M3, respectively (c.g., M2G). These lesions, however, may not be significant in cells as polymerization of malondialdehyde is relatively slow at neutral pH. (B) The l,7V2-propano-dG DNA adducts produced by acrolein, crotonaldehyde, and 4-hydroxy-2-nonenal (HNE). Stereochemistry is not shown. The l.A -acrolcin-dG consists of three isomers. The 1, AAcrotonaldchyde-dG consists of two isomers. The FAAlINF-dGconsistsof four isomers. (C)EthenoDNAadductsproduced by 2,3-epoxy-4-hydroxynonenal. Further oxidation of 4-hydroxynonenal produces 2,3-epoxy-4-hydroxynonenal, which reacts with DNA to form the exocyclic etheno adducts.

The other compound, called Zl, which was much more acid-labile, was hydrolyzed to equimolar amounts of pyruvate and shikimate, and was tentatively assigned the structure of shikimate 3- or 5-enolpyruvate ether. In a more recent study, it was found that the barium salt of Zl does not absorb in the carbonyl region of the infrared absorption spectrum (no ester structure), and that it has a strong band at 8.2iu characteristic of a vinyl ether. It is oxidized very rapidly by periodate, giving rise to an unstable compound with maximum absorption at 235 m i ( = 4000). A similar unstable chromophore, most likely having the structure XVII, was produced by periodate oxidation of shikimate 3-phosphate but not of shikimate 5-phosphate. (3-Methyl-crotonaldehyde shows Xm 235, t = 6700. ) These observations suggest that Zl is shikimate 3-enolpyruvate ether (XVIII). 

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