Oxidation of 2-butenal

The kinetics of the photochemical oxidation of 2-butenal in a pure state or in n -decane solution have been studied by Niclause and coworkers [34], Oxidation taking place between 0 and 16° C under UV irradiation and a partial oxygen pressure of 18—700 torr produces kinetics similar to those of the photochemical oxidation of saturated aldehydes, viz. 

By assuming a reaction mechanism similar to that for the oxidation of n-decanal, the oxidability , ft3 fee1 2, at 1.5°C has an approximate value of 8 X 10-3l1 2 mole-1 2 s-1 2, and ft5 (fc4fc6)-1 2 a value of about 0.5. 

Maaraui et al. [72] have investigated the thermal oxidation in rc-decane. The chain length was high, 1000—2000. They used inhibitors to investigate the mechanism of initiation and proposed the reaction 

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Finally, Ven yaminov et al. [338] compare a Sn/Sb = 4/1 catalyst with bismuth molybdate (2/3) at 450°C and note that the Sn—Sb catalyst is less hampered by a drop in selectivity at high degrees of conversion. On the other hand, lower yields are found in the oxidation of 2-butene (compared with 1-butene). The superiority of the bismuth molybdate catalyst in this respect is probably connected with its greater isomerizing capacity. 

The oxidation of 2-butene with selenium dioxide in acetic acid solution produces l-acetoxy-2-butene as the oxidation product of the olefin and bis(l-methyl-2-acetoxypropyl)-selenide (I) as the final reduced state of the oxidant instead of elemental selenium. Further, (I) may act as a catalyst for the oxidation of 2-butene with peracetic acid or oxygen to 3-acetoxy-1-butene. A mechanism is proposed to explain the formation of selenides in the oxidation of olefins with selenium dioxide and their catalytic activity in the oxidation of olefins with other oxidants. 

Purification of the Organoselenium Compounds. After the oxidation of 2-butene with selenium dioxide was completed, the acetic acid solvent and the volatile reaction products were distilled at reduced pressure (10 mm. HgA). The residue, a yellow oil, was purified by adsorption chromatography in a column packed with silica gel. n-Hexane and ethyl ether were used as eluents. The same procedure was applied to the fractionation and purification of the organoselenium compounds obtained from the oxidation of bis(l-methyl-2-acetoxypropyl) selenide with peracetic acid. 

Oxidation of 2-Butene with Oxygen, Catalyzed by Bis (1-methyl-2-acetoxypropyl)selenide. This reaction was conducted at 120°C. and total pressures from 80 to 400 p.s.i.g. and oxygen partial pressures from 5 to 40 p.s.i.g. 

Oxidation of 2-Butene with Selenium Dioxide. The oxidation was conducted in glacial acetic acid at atmospheric pressure and temperatures from 56° to 80°C. Approximately 3 moles of olefin were absorbed per mole of selenium dioxide consumed. The reaction produced 0.85 mole of l-acetoxy-2-butene, 0.03 mole of 3-acetoxy-l-butene, and 0.85... 

The product of the oxidation of 2-butene with oxygen in the presence of bis (l-methyl-2-acetoxypropyl) selenide was 3-acetoxy-l-butene in acetic acid as solvent and 3-hydroxy-l-butene(a-methylallyl alcohol) in aqueous dioxane. The reaction rate depends on the selenide concentration. 

Peracetic Acid Oxidation of 2-Butene Catalyzed by Bis (1-methyl-2-acetoxypropyl) selenide. Based upon the identification of an alkyl-selenenyl acetate among the products of the oxidation of bis(l-methyl-2-... 

For the HO-substituted alkoxy radicals formed from the higher alkenes, Atkinson et al. [112], Akimoto et al. [111], and this group [109] have shown that unimoiecular dissociation, analogous to reaction (34), is dominant over reaction with 02, leading to the formation of aldehydes and HOO. For instance, the reaction sequence for the HO-initiated oxidation of 2-butene in the presence of NO is shown below. 

In a study of the conversion of w-butane to maleic anhydride, Bissot and Benson 157) noted that cis-2-butene reacted faster and more selectively than n-butane, in agreement with data of Table XIV. Using a cobalt molybdate catalyst at 450-475°, they obtained 92 % conversion of cis-2-C4Hg and 36 % selectivity to maleic anhydride, for a C X Sj 100 (or yield) value of 32%. From n-butane the best yield was 15%, but this could be raised to 25% by a two-stage operation. Rather similar results for oxidation of 2-butenes were reported by Skinner and Tieszen 158), who used a Mo/V/P = 9/3/1 catalyst at about 350° and obtained a yield of 28.3 %. Other products were acetaldehyde, formaldehyde, acrolein, crotonaldehyde, formic acid, and acetic acid. A water spray to quench products leaving the catalyst bed was used for best results. 

Stereospecific reaction A reaction in which the stereochemistry of the product is dependent on the stereochemistry of the starting material. For example, oxidation of 2-butene by osmium tetroxide is stereospecific oxidation of a s-2-butene gives meso-2,3-butanediol, whereas oxidation of frans-2-butene gives a racemic mixture of the enantiomers of 2,3-butanediol. (The term"regiospecific"is used analogously.)... 

The benzoquinone simply oxidizes the Pd(0) back to Pd(II) to maintain a constant concentration of Pd(ll). Note the effect of changing concentrations on the observed rate and write a rate expression for the oxidation of 2-buten-l-ol in terms of all involved concentrations (except benzoquinone, which does not affect the rate). Round off all orders to the nearest whole number. Select a run from the table and calculate an actual rate constant for the reaction and give the units for it. 

Figure ll-D-7. 03-iiutiated oxidation of 2-buten-l-ol (Qrosjean and Grojean, 1995). 

Noda et al. (2000) investigated the N03-initiated oxidation of 2-buten-l-ol. Only 20% of the reacted alcohol was identified as gas-phase products. The main observed products were formaldehyde (10 3)%, acetaldehyde (12 2)%, and glycolaldehyde (7 2)%. The remaining 80% was attributed to the formation of nitrooxy and multifunctional compounds. 

R. H. Schwaar and S. Morimoto, Methyl Ethyl Ketone by Direct Oxidation of n-Butenes, Process Economics Program, Review No. 87-2-3, SRI International, Menlo Park, Calif., Oct. 1988. 

Hydroboration-oxidation of ( )-2-(p-anisyl)-2-butene yielded an alcohol A, mp 60°C, in 72% yield. When the same reaction was performed on the Z alkene, an isomeric liquid alcohol B was obtained in 77% yield. Suggest reasonable structures for A and B, and describe the relationship between them. 

Olefin metathesis is the transition-metal-catalyzed inter- or intramolecular exchange of alkylidene units of alkenes. The metathesis of propene is the most simple example in the presence of a suitable catalyst, an equilibrium mixture of ethene, 2-butene, and unreacted propene is obtained (Eq. 1). This example illustrates one of the most important features of olefin metathesis its reversibility. The metathesis of propene was the first technical process exploiting the olefin metathesis reaction. It is known as the Phillips triolefin process and was run from 1966 till 1972 for the production of 2-butene (feedstock propene) and from 1985 for the production of propene (feedstock ethene and 2-butene, which is nowadays obtained by dimerization of ethene). Typical catalysts are oxides of tungsten, molybdenum or rhenium supported on silica or alumina [ 1 ]. 

Reaction of iV-aminocarbonyl-2-phenylethylamines with mesityl oxide and 2-butenal afforded l,2,3,6,7,llb-hexahydro-477-pyrimido[6,l- ]isoquinoline-4-ones <2003MC278>. 9,10-Dimethoxy-l,2,3,6,7,llb-... 

Acidification of the mixture, after the oxidation is complete, produces 2 moles of acetic acid for each mole of 2-butene. 

Figure 13.6 Variation of both the conversion of 2-butene and the selectivity to trimethyl-pentanes (TMP), with the nature of the metal oxide support obtained during the isobutene/ 2-butene alkylation at 32°C over sulfated supported on different metal oxides. (After Ref. 35.)...

A thermal oxidation of 2,3-dimethyl-2-butene, 16, occurs in NaY when the temperature of the oxygen-loaded zeolite in raised above — 20°C [35], Similar thermally initiated oxidations were not observed for the less electron rich tram-or cix-2-butene. Remarkably, pinacolone was conclusively identified as one of the products of the reaction of 16, This ketone is not a product of the photochemical Frei oxidation (vide supra) and underscores the very different character of these two reactions and the complexity of the oxygen/16 potential energy surface, A rationale for the different behavior could lie in the different electronic states of the reactive oxygen-CT complex in the thermal and photochemical reactions. Irradiation could produce an excited triplet-state CT complex ( [16 O2] ) and/ or ion pair ( [16 02 ] ) with different accessible reaction channels than those available to a vibrationally excited ground-state triplet complex ( [16 "02]) and/... 

Isolation and Identification of Hydroperoxide. A solution produced by oxidizing trans-2-butene was concentrated at reduced pressure without heating from 0.085M to 1.5M. The hydroperoxide was isolated from the concentrate by preparative chromatography under the following conditions a 5-foot 3/8-inch column of aluminum containing 10% diisodecyl phthalate on Fluoropak 80 Autoprep 705 with flame ionization detector carrier, 200 ml. per minute helium split 8 to 1 between trap and detector ... 

Kemper, R.A. Elfarra, A.A. (1996) Oxidation of 3-butene-l,2-diol by alcohol dehydrogenase. Chem. Res. Toxicol., 9, 1127-1134... 

Oxidation of Bis (1-methyl-2-acetoxypropyl) selenide in the Presence of 2-Butene. The oxidation of the selenide was conducted at 5°C. in glacial acetic acid solution saturated with 2-butene. The initial reaction was discontinued after adding 0.3 mole of peracetic acid per mole of selenide. The temperature was raised to 45°C., and the reaction was allowed to proceed for 15 minutes under a 2-butene atmosphere. These steps were repeated several times until the addition of 7 moles of peracetic acid per mole of selenide was completed. 

Oxidation of Bis (l-methyl-2-acetoxypropyl) selenide in the Presence of 2-Methyl-2-butene. The analysis of the solution near the beginning of the reaction showed that 3-acetoxy-l-butene was the only initial product of the oxidation, but after adding 0.5 mole of peracetic acid per mole of selenide, increasing amounts of the oxidation products of 2-methyl-2-butene, such as 2-methyl-3-acetoxy-l-butene, and 3-methyl-3-acetoxy-l-butene were detected. After adding 4 moles of peracetic acid per mole of selenide, the allylic products from the oxidation of 2-methyl-... 

Oxidation of 2,4-dimethyl- 2 -pentane gave the desired epoxide in high yield- (Eq. 109), and no other products were isolated,7 7 The reaction was conducted at 0° in a mixture of acetic anhydride and carbon disulfide. Under these conditions 2-methyl-2-butene. in which a... 

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