Butyraldehyde oxidation

When the alcohol (1) Is contaminated with small amounts of butyraldehyde, oxidation proceeds vfith a much lower yield of product. 

In the literature, it is conunonly admitted that alkoxy radicals RO are involved in three types of reactions, oxidation, isomerization, decomposition, which occur according to parallel pathways. It is the reason for which, the products generated by the reactions of the n-butoxy radical have been analysed and separated in three different groups corresponding to each pathway (1-butanol apart, because it is likely produced by RO + RH ROH + R) butyraldehyde (oxidation), other compounds in C4 resulting from the isomerization, and species in C3 formed by the... 

Direct fluorination of aliphatics and non-C moieties Direct fluorination of benzenoid aromatics Direct fluorination of heterocyclic aromatics Oxidations of alcohols, diols and ketones with fluorine Photo-oxidation of a-terpinene and cyclopentadiene Oxidation of benzyl alcohol to benzaldehyde Homogeneously catalyzed oxidation of butyraldehyde Oxidation of sulfite to sulfate Photochlorination of aromatic isocyanates... 

Another attractive commercial route to MEK is via direct oxidation of / -butenes (34—39) in a reaction analogous to the Wacker-Hoechst process for acetaldehyde production via ethylene oxidation. In the Wacker-Hoechst process the oxidation of olefins is conducted in an aqueous solution containing palladium and copper chlorides. However, unlike acetaldehyde production, / -butene oxidation has not proved commercially successflil because chlorinated butanones and butyraldehyde by-products form which both reduce yields and compHcate product purification, and also because titanium-lined equipment is required to withstand chloride corrosion. 

Propylene-Based Routes. The strong acid-catalyzed carbonylation of propylene [115-07-1] to isobutyric acid (Koch reaction) followed by oxidative dehydration to methacrylic acid has been extensively studied since the 1960s. The principal side reaction in the Koch reaction is the formation of oligomers of propylene. Increasing yields of methacrylic acid in the oxydehydration step is the current focus of research. Isobutyric acid may also be obtained via the oxidation of isobutyraldehyde, which is available from the hydroformylation of propylene. The -butyraldehyde isomer that is formed in the hydroformylation must be separated. 

Oxidation of butyraldehyde to butyric acid [107-92-6]is most commonly carried out employing air or oxygen as the oxidant. Alternatively, organic oxidants, eg, cumene hydroperoxide, can also be employed effectively to give high yields of butyric acid, (4). 

Several species of bacteria under suitable conditions cause / -butyraldehyde to undergo the Canni22aro reaction (simultaneous oxidation and reduction to butyric acid and butanol, respectively) this reaction can also be cataly2ed by Raney nickel (7). The direct formation of butyl butyrate [109-21 -7] or isobutyl isobutyrate [97-85-8](Vish.ch.erik.o reaction) from the corresponding aldehyde takes place rapidly with aluminum ethylate or aluminum butyrate as catalyst (8). An essentially quantitative yield of butyl butyrate, CgH2 02, from butyraldehyde has been reported usiag a mthenium catalyst, RuH,[P(C,H,)3], (9). 

Butyric acid, the simple oxidation product of -butyraldehyde, is used chiedy in the production of cellulose acetate butyrate [9004-36-8]. Sheets of cellulose acetate butyrate are used for thermoformed sign faces, bUster packaging, goggles, and face shields. 

Butyric acid is made by air-oxidation of butyraldehyde, which is obtained by appHcation of the oxo synthesis to propylene. Isobutyric acid is made from isobutyraldehyde, a significant product in the synthesis of butyraldehyde (see Butyraldehydes). Butyraldehyde is also used to make 2-ethylhexanoic acid. 

Neo acids are prepared from selected olefins using carbon monoxide and acid catalyst (4) (see Carboxylic Acids, trialkylacetic acids). 2-EthyIhexanoic acid is manufactured by an aldol condensation of butyraldehyde followed by an oxidation of the resulting aldehyde (5). Isopalmitic acid [4669-02-7] is probably made by an aldol reaction of octanal. 

In 1909, Patemo and Chieffi noted that mixtures of tri- or tetra-substituted olefins and aldehydes formed trimethylene oxides when exposed to sunlight. Biichi later repeated Patemo s experiments by irradiating 2-methyI-2-butene in the presence of benzaldehyde, butyraldehyde, or aeetophenone and rigorously purifying and identifying the resulting products. The reaction thus bears the name of its two primary pioneers and has come to represent any photo-catalyzed [2 + 2] electrocyclization of a carbonyl and an alkene. 

The acidity dependences are not simple. V(V) is thought to form a complex with the enol which undergoes slow oxidative breakdown. Propionaldehyde and n-butyraldehyde are, however, oxidised by Mn(III) pyrophosphate with a zero-order dependence on oxidant concentration but first-order dependences on substrate and HjO " concentrations. Here oxidation immediately follows enol formation. Ce(IV) sulphate oxidises acetaldehyde at a rate much faster than enolisation . 

The homogeneously catalyzed oxidation of butyraldehyde to butyric acid is a well-characterized gas/Hquid reaction for which kinetic data are available. It thus serves as a model reaction to evaluate mass transfer and reactor performance in general for new gas/liquid micro reactors to be tested. This reaction was particularly used to validate a reactor model for a micro reactor [9, 10]. 

The homogeneously catalyzed oxidation of butyraldehyde to butyric acid was used to analyse reactor performance for different flow patterns (or for different Weber numbers) [9,10]. Hence it relates to the possibility of setting various flow patterns in gas/Hquid micro devices and hence controlling mass transfer. 

Oxidation of Aldehydes to Carboxylic Acids Investigated in Micro Reactors Cas/liquid reaction 26 [CL 26) Homc eneously catalyzed oxidation of butyraldehyde to butyric acid... 

Butyraldehyde is oxidized to butyric acid in the presence of air using manganese acetate as catalyst [9, 10],... 

GL 26] [R 3] [P 28] Conversions from 2 to 42% were found for the oxidation of butyraldehyde [10], The highest conversions were obtained for large gas and liquid flows. On increasing the ratio of gas and liquid superficial velocities from 5 to 53, an increase in conversion from 10 to 41% resulted. 

Isobutyraldehyde, 4 459 14 584 animal toxicty, 4 466t effect of unsaturation on toxicity, 2 69t isobutyl alcohol manufacture from, 4 397 oxidative dehydrogenation of, 16 252 physical properties of, 4 459t quality specifications, 4 465t Isobutyraldol, butyraldehyde derivative, 4 461... 

Higher alcohols, however, cannot be used as neat liquids in electrolysis. For anodic oxidation those alcohols must be dissolved in appropriate solvents. Acetonitrile is the most frequently used solvent for that purpose. Electrochemical oxidation of n-butyl alcohol to n-butyraldehyde was achieved in moderately dilute acetonitrile solution in a current yield of 77% [9]. 

Condensation of butanol has been carried out on alkaline earth metal oxides at 273 K (13,121). This condensation reaction yields 2-ethyl-3-hydroxy-hexanal as a main product other products, such as 2-ethyl-2-hexenal (arising from the dehydration of 2-ethyl-3-hydroxy-hexanal), n-butyl-K-butyrate (arising from the Tishchenko reaction of butyraldehyde), and 2-ethyl-3-hydroxy- -hexyl butyrate (arising from the Tishchenko reaction of 2-ethyl-3-hydroxy-hexanal), are also formed (Scheme 12). 

By analogy between the oxo forms of vanadium(V) and iron(IV), the latter being the active species in oxidations by cytochrome P-450, the system constituted by vanadium oxide as the catalyst, and t-butylhydro-peroxide, as the oxidant, gives good results in the conversion of olefins to the corresponding epoxides. With the supported "clayniac" catalyst, in the presence of i-butyraldehyde as a sacrificial reducer, olefins are epoxidized in good yields by compressed air at room temperature, in a convenient procedure. 

Shu and co-workers (35) identified 2-isobutyl-3,5-diisopropylpyridine, 2-pentyl-3,5-dimethylpyridine, and its dihydro derivative obtained under similar conditions. Sultan (29) confirmed the presence of 3,5-diethyl-2-propylpyridine in a model system consisting of butyraldehyde and ammonium sulfide. Our proposed mechanism of their formation (20) consists of three steps 1) aldol condensation of the starting aldehydes to 2,4-alkadienals, 2) imine formation with ammonia, and 3) subsequent cyclization and oxidation to corresponding pyridines. An alternate mechanism, suggested by Shu and co-workers (33), takes into consideration the isolated dihydro derivatives. Hwang and co-workers described another dihydro derivative (19, R = Bu, R = R" = Pr, R= H) (37). 

Among the aldehydes and ketones tested acetone was least toxic, formaldehyde, butyraldehyde, and crotonaldehyde next, and mesityl oxide most toxic. In this group of compounds temperature was a major factor, both formaldehyde and mesityl oxide being much more toxic at 40 than at 25 C. None were outstanding as cholesterol solvents, but mesityl oxide was the best it penetrated nematodes the most easily and killed in the lowest concentrations. 

Under the same reaction conditions, acetaldehyde and butyraldehyde displayed near-complete conversion (greater than 95%). The photocatalytic oxidation of the alcohol 1-butanol displayed similarly high conversion levels, although conversion of methanol was somewhat lower. The oxygenated compounds methyl-t-butyl ether (MTBE), methyl acrylate, 1,4 dioxane, and vinyl acetate displayed conversion levels ranging from 92% to 100%. The lowest conversion levels of the oxygenated compounds studied were seen with the ketones used [acetone and 2-butanone (methylethylketone)], which displayed conversions of approximately 80%. The initial conversion levels seen with -hexane were similar... 

Ethyl alcohol has been made by the hydration of ethylene (9) since 1930. Like isopropyl alcohol, part of the output is used as a solvent, but most is converted to other oxygenated chemicals. Its most important raw material use is conversion to acetaldehyde by catalytic air oxidation. Acetaldehyde, in turn, is the raw material source of acetic acid, acetic anhydride, pentaerythritol, synthetic n-butyl alcohol (via aldol condensation), butyraldehyde, and other products. Butyraldehyde is the source of butyric acid, polyvinyl butyral resin, and 2-ethylhexanol (octyl alcohol). The last-named eight-carbon alcohol is based on the aldol condensation of butyraldehyde and is used to make the important plasticizer di-2-ethylhexyl phthalate. A few examples of the important reactions of acetaldehyde are as follows ... 

Cannizzaro reaction. Aromatic aldehydes (and other aldehydes in which a-hydrogen atoms arc absent, e.g., formaldehyde, trimcthylacetaldehyde, and a-hydroxy-tso-butyraldehyde) under the influence of strong aqueous or alcoholio alkali undergo simultaneous oxidation and reduction yielding the alcohol and corresponding acid. Thus —... 

---