Isobutyrate, formation

M-Butyl formate. Ethyl iso-butyrate IsO -butyl acetate Ethyl butyrate -Propyl propionate Iso-amyl formate, -But> l acetate Iso-propyl butyrate Iso-butyl propionate n-Propyl -butyrate -Butyl propionate Iso-butyl isobutyrate Ethyl lactate Iso-butyl butyrate Cycloheicyl formate -Butyl -butyrate Iso-propyl lactate. Cyclohexyl acetate Diethyl oxalate Di-iao-propyl oxalate... 

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. 

Although not commercialized, both Elf Atochem and Rn hm GmbH have pubUshed on development of hydrogen fluoride-catalyzed processes. Norsolor, since acquired by Elf Aquitaine, had been granted an exclusive European Hcense for the propylene-hydrogen fluoride technology of Ashland Oil (99). Rn hm has patented a process for the production of isobutyric acid in 98% yield via the isomerization of isopropyl formate in the presence of carbon monoxide and hydrofluoric acid (100). 

CitroneUol is easUy esterified with acid anhydrides or carboxylic acids, catalyzed by mineral acids. The price of citroneUyl acetate [150-84-5] in 1995 was 10.45/kg (45). Other esters such as the formate and isobutyrate ate also used. 

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). 

Formate Ester 3. Acetate Ester 6. Trichloroacetate Ester 10. Phenoxyacetate Ester 19. Isobutyrate Ester... 

Although Ce(IV) oxidation of carboxylic acids is slow and incomplete under similar reaction conditions , the rate is greatly enhanced on addition of perchloric acid. No kinetics were obtained but product analysis of the oxidations of -butyric, isobutyric, pivalic and acetic acids indicates an identical oxidative decarboxylation to take place. Photochemical decomposition of Ce(IV) carbo-xylates is highly efficient unity) and Cu(ll) diverts the course of reaction in the same way as in the thermal oxidation by Co(IIl). Direct spectroscopic evidence for the intermediate formation of alkyl radicals was obtained by Greatorex and Kemp ° who photoirradiated several Ce(IV) carboxylates in a degassed perchloric acid glass at 77 °K in the cavity of an electron spin resonance spectro-... 

Since formation of citraconic anhydride from pyruvic acid is one of "acid to acid type" transformations, such as reactions from isobutyric acid to methacrylic acid and from lactic acid to pyruvic acid, the required catalysts must be acidic [11). If the catalysts are basic, it may be impossible to obtained acidic products, because basic catalysts activate selectively acidic molecules and, as a result, they show a very high activity for the decomposition of acidic products [11]. 

N-VALERIC ACID ISOBUTYL FORMATE N-PROPYL ACETATE ETHYL PROPIONATE METHYL BUTYRATE METHYL ISOBUTYRATE PIPERIDINE N-PENTANE 2-METHYL BUTANE 2 2-DIMETHYL PROPANE... 

Actually one observes (Fig. 4) the formation of acetone and isopropanol, with only traces of isobutyric acid (reaction (9), both products being formed in amounts exceeding 80 % of the amount of DiPK decomposed as indicated by the initial rate of formation). 

In the presence of nitroxide I, diisopropyl ketone photooxidation takes a course differing considerably from that without this additive (Fig. 5). In this case high yields of isobutyric acid and acetone were obtained, presumably as products arising from the postulated peroxy radicals c and d. On the other hand, the formation of isopropanol is almost completely suppressed. 

If one takes into account not only the initial slope of the curves but also the part played by the formation of isobutyrate it can be seen that the amount of reaction products formed is almost equivalent to the loss of DiPK. In this case the formation of isobutyric acid represents the most important difference compared with irradiation without additive. It shows that in the presence of nitroxide the acyl radical may not only be captured by oxygen but can also react further as acyl-peroxy radical, without losing its carbonyl group in the process. 

The change in the product mixture in the presence of nitroxide I, i.e., formation of isobutyric acid instead of isopropanol, and... 

A second mechanism involving as intermediate step a stable hydroxylamine ether (isopropyl I-ether) is also a possibility (reaction (15)). In a second step the ether would undergo cleavage by the acylperoxy radical with formation of isobutyric acid and acetone and liberation of the nitroxide (reaction (16)) ... 

The observed formation of isobutyrate (Figs. 5 and 6) would appear to be one of the possible reasons for the slow decrease in the nitroxide concentration. The formation of isobutyrate can be seen as a reaction competing with the capture of the acyl radicals by oxygen. The absence of isopropyl ether in the reaction mixture is explained by its immediate cleavage - following its formation analogous to isobutyrate - to nitroxide by oxygen-centered radicals (mainly acyl peroxy radicals). 

Irradiation of diisopropyl ketone under oxygen in the presence of the hindered piperidine II likewise results in formation of isobutyric acid, acetone and small amounts of isopropanol. At the same time the amine is quantitatively oxidized to the corresponding nitroxide I (Fig. 7, reaction (17)) ... 

The formation of isobutyric acid in the presence of the additives studied, and the results of additional studies (di-tert.-butyl peroxyoxalate/isobutyroal-dehyde/amine), point to the intermediate formation of acyl peroxy radicals. 

At 300 K and below, when hydroperoxides are stable, the decay of PMP peroxyl radicals gives rise to low-molecular-weight products, namely, water, acetone, and isobutyric aldehyde. The formation of these products can be explained by the breakdown of various peroxyl radicals with production of hydroxyl ion and cleavage of the C—C bond. 

The VFAs, primarily formate, acetate, propionate, n-butyrate and isobutyrate, can be determined analytically on an ion chromatograph (Standard Methods for the Examination of Water and Wastewater, 1998). Determination of fermentable, readily biodegradable substrate, SF, and fermentation products, SA, in units of COD requires that the VFA components be converted to this unit. The following example using formate demonstrates this ... 

Radiolysis of isobutyric acid at 195 K results in the formation of only one radical intermediate, the hydrogen abstraction radical III. The decarboxylation radical and the anion radical are both unstable at this temperature and react forming the abstraction radical and other products. The hydrogen which is abstracted is generally that which is attached to the carbon atom a to the carboxyl group. 

METHYL ISOBUTYL KETONE n-PENTYL FORMATE n-BUTYL ACETATE sec-BUTYL ACETATE tert-BUTYL ACETATE ETHYL n-BUTYRATE ETHYL ISOBUTYRATE ISOBUTYL ACETATE n-PROPYL PROPIONATE CYCLOHEXYL PEROXIDE DIACETONE ALCOHOL 2-ETHYL BUTYRIC ACID n-HEXANOIC ACID 2-ETHOXYETHYL ACETATE HYDROXYCAPROIC ACID PARALDEHYDE... 

As with inorganic solid catalysts, the most extensively studied system was acetic acid—ethanol [428,432,434,444—448]. Other alcohols used in kinetic studies were methanol [430,449,450], 2-propanol [438], 1-bu-tanol [429,431,433,451—458], allyl alcohol [459], 1-pentanol [434] and ethyleneglycol [460] besides acetic acid, the reactions of formic [450], propionic [443,461], salicylic [430,449], benzoic [453—457] and oleic acids [430,451—453] and of phthalic anhydride [462] have been reported. Investigation of a greater variety of reactants is reported in only one paper [463] six alcohols (C4, Cs and C8) and five acids (mainly dicarboxylic were studied. Transesterification kinetic studies were performed with ethyl formate [437,439,441], isobutyrate [437,439—441] acetate [402, 435—437,439—442], methoxyacetate [441] and acrylate [403,404,464, 465] the alcohols used were methanol [402,435,437,439—442,450],... 

Isobutyramide has been prepared by the action of concentrated aqueous ammonia on isobutyryl chloride 3 or methyl isobutyrate 4 by distillation of ammonium isobutyrate 5 or a mixture of isobutyric acid and potassium thiocyanate.6 Hydrolysis of isobutyronitrile also results in the formation of isobutyramide. 7... 

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