Croton aldehyde

Cyclic g-haloacetals and -ketals have been prepared by variations on two basic methods. The most frequently used method involves the combination of an a,B-unsaturated carbonyl compound (acrolein, methyl vinyl ketone, croton-aldehyde, etc.) a diol, and the anhydrous hydrogen halide. All possible sequences of combining these three have been used. In most cases the... 

Similar kinetics are obtained with a-methylacraldehyde , but with croton-aldehyde the reaction is essentially first order in Mn(III), tending to zero-order only at relatively high [Mn(Ill)]. The oxidation of acraldehyde is viewed as a rapid reaction preceded by a slow acid-catalysed hydration, viz. 

Best yields were obtained from Eastman s best-grade croton-aldehyde which had been distilled immediately before use. 

Ru(II)-TPPTS to the corresponding unsaturated alcohols in biphasic mode. If one compares the reaction times until full conversion, it becomes clear that the reaction rate correlates with the solubility of the substrate in the aqueous phase, as expected. The latter decreases with increasing chain length or branching of the chain at the C3-atom. In contrast to heterogeneously catalysed hydrogenations of o , d-unsaturated aldehydes, the steric hindrance of substituents at the C3-atom only plays a minor role in the coordination mode of the substrate at the metal centre, since selectivity differences from croton-aldehyde to citral are marginal. 

Synonyms AI3-18303 2-Butenal CCRIS 909 Crotenaldehyde Crotonal Crotonic aldehyde EINECS 224-030-0 1,2-Ethanediol dipropanoate Ethylene glycol dipropionate Ethylene dipropionate Ethylene propionate p-Methylacrolein NC1-C56279 NSC 56354 Propylene aldehyde RCRA waste number U053 Topanel UN 1143. 

CP 1309, see Pentachlorophenol CPD-244, see 2-Nittopropane CPD-926, see Dibenzofuran 4-CPPE, see 4-Chlorophenyl phenyl ether p-CPPE, see 4-Chlorophenyl phenyl ether Crag sevin, see Carbaryl Crawhaspol, see Trichloroethylene 2-Cresol, see 2-Methylphenol 4-Cresol, see 4-Methylphenol oCresol, see 2-Methylphenol p-Cresol, see 4-Methylphenol Crestoxo, see Toxaphene Crestoxo 90, see Toxaphene oCresylic acid, see 2-Methylphenol p-Cresylic acid, see 4-Methylphenol oCresyl phosphate, see Tri-ocresyl phosphate Crisalin, see Trifluralin Crisalina, see Trifluralin Crisfuran, see Carbofuran Crisulfan, see a-Endosulfan, p-Endosulfan Crisuron, see Diuron Crolean, see Acrolein Crop rider, see 2,4-D Crotenaldehyde, see Crotonaldehyde Crotilin, see 2,4-D Crotonal, see Crotonaldehyde Crotonic aldehyde, see Crotonaldehyde CRS, see Phenol Crunch, see Carbaryl Cryptogil OL, see Pentachlorophenol CS, see oChlorobenzylidenemalononitrile, Methyl mercaptan... 

This reaction appears to be of general application croton-aldehyde diethyl acetal is formed in 68% yield b.p. 145-147° ... 

In a high-pressure autoclave, arranged for agitation by shaking or rocking, are placed 286 g. (336 ml., 4.08 moles) of croton-aldehyde, 294 g. (5.06 moles) of methyl vinyl ether, and 1.1 g. of hydroquinone (Notes 1 and 2). The autoclave is heated to 200° (Note 3) and held there for 12 hours. The autoclave is cooled and vented, and the black product is distilled through a 1 by 60 cm. helix-packed column. The yield of 3,4-dihydro-2-methoxy-... 

Cresyl Glycidyl Ether Cresylic Acid Cresylic Acids Croplas Eh Crotenaldehyde Crotonaldehyde Crotonic Aldehyde Crotonoel... 

CROTONALDEHY DE beta-Methylacrolein, Crotenaldehyde, Crotonic Aldehyde, trans-2-Butenal Flammable Liquid, II 3 3 2... 

Formaldehyde, acetaldehyde, acetone, and carbon monoxide were common combustion products of the four hexanes. Propionaldehyde, n-butyraldehyde, acrylic aldehyde, crotonic aldehyde, and methyl ethyl ketone were all found as intermediates in the combustion of n-hcxane. Acetaldehyde and acetone were prominent and propionaldehyde and acrylic aldehyde were present among the intermediates from 2-methylpentane. Acetaldehyde and methyl ethyl ketone were peculiarly characteristic of 3-methyl-pentane and acetaldehyde, acetone, and pivalic aldehyde were characteristic of 2,2-dimethylbutane. In other words, the intermediate monocarbonyl combustion products... 

The palladium [Pd(Ph3)4]-catalysed 3 + 3-cycloaddition of trimethylenemethane with azomethineimines produced hexahydropyridazine derivatives under mild conditions (40 °C).171 The Lewis acid-catalysed formal oxa-[3 + 3]-cycloaddition of a,f+ unsaturated aldehydes with 6-methyl-4-hydroxy-2-pyrone, 1,3-diketones, and viny-logous silyl esters yielded a variety of pyrones at room temperature.172 Croton-aldehyde has been converted to 6-hydroxy-4-methylcyclohex-l-enecarboxaldehyde by an enantioselective 3 + 3-cycloaddition catalysed by proline. This methodology was used in the synthesis of (—)-isopulegol hydrate, (—)-cubebaol, and (—)-6-hydroxy-4-methylcyclohex-l-ene-1-methanol acetate, an intermediate in the total synthesis of the alkaloid magellanine.173... 

The new synthesis is superior to the present process based on ketene and croton-aldehyde in terms of the variable costs (butadiene and acetic acid are inexpensive starting materials). However, high conductive salt concentrations coupled with low concentrations (2-4 %) of the desired product in the electrolyte together with considerable corrosion problems make the working up procedure much more expensive. Therefore, the new process so far has not been used industrially. 

The methoxy-substituted acetal C is isolated and is subjected to another two reactions (1) the acetal function is hydrolyzed under acidic conditions to provide the methoxylated aldehyde E. (2) With a catalytic amount of sodium methoxide, the methoxylated aldehyde E reacts via an Elcb elimination, which leads to the formation of the poly-unsaturated aldehyde D. The substrates A and B of the three-step reaction sequence in Figure 12.23 derive from crotonic aldehyde (E13C-CE[=CE[-CH=0) the respective methods of preparation are outlined in the figure. The final product, which is the highly unsaturated aldehyde D, displays the structure of an aldol condensation product, namely of the crotonic aldehyde mentioned above. 

Table 10.1 presents typical specifications for a polymerization-grade product, as well as some physical properties. Prohibited impurities refer to inhibitors (croton-aldehyde, vinyl acetylene), chain-transfer agents (acetic acid, acetaldehyde, acetone) and polymerizable species (vinyl crotonate), while methyl and ethyl acetate impurities are tolerated. 

Crotonic aldehyde +1, 3 butadiene. = 1.5X109 e l9t700IRT. cc. mole"1... 

Norrish has suggested that the low quantum yield is probably due to the complexity of the molecule. Decomposition cannot occur if there is a wide distribution of energy among the various parts of a complex molecule for then there is not a sufficient quantity left at the one particular bond where chemical disruption must occur. The probability that a fraction of the whole amount sufficient for chemical decomposition will reach the proper bond at the proper instant depends largely on the complexity of the molecule and the amount of energy introduced. With acetone this probability appears to be about 0.2 with crotonic aldehyde the probability is zero, for Blacet and Roof35 have shown that this substance does... 

Oxybutyric Acid (CH3-CH(OH)-CH2-COOH).—From this acid were obtained in the positive electrolyte crotonic aldehyde and a little formic acid, also resinous substances. Considerable quantities of carbonic acid, also a little carbon monoxide and unsaturated hydrocarbons, are formed. The small quantities... 

These findings seemed to point to catalyst degradation induced by the reagents, and indeed further NMR analysis showed extensive catalyst degradation in the presence of acrolein, less degradation with croton-aldehyde, and essentially no degradation with cinnamaldehyde (nitrone did not exert any effect on the catalyst stability). In agreement with the results of these experiments, we observed also that the non-supported catalyst showed a marked instability and decrease in chemical efficiency when recycled. 

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