Degradation propionic acid

Other possible chemical synthesis routes for lactic acid include base-cataly2ed degradation of sugars oxidation of propylene glycol reaction of acetaldehyde, carbon monoxide, and water at elevated temperatures and pressures hydrolysis of chloropropionic acid (prepared by chlorination of propionic acid) nitric acid oxidation of propylene etc. None of these routes has led to a technically and economically viable process (6). 

Degradatiou. Heating of succinic acid or anhydride yields y-ketopimehc ddactone, cyclohexane-1,4-dione, and a mixture of decomposition products that include acetic acid, propionic acid, acryUc acid, acetaldeide, acrolein, oxaUc acid, cyclopentanone, and furane. In argon atmosphere, thermal degradation of succinic anhydride takes place at 340°C (123). Electrolysis of succinic acid produces ethylene and acetylene. 

JCS2689) and 5-bromomethylpyrimidine (458) and diethyl benzyloxycarbonyl-aminomalonate (459) give initially, diethyl a-benzyloxycarbonylamino-a-(pyrimidin-5-ylmethyOmalonate (460) which can be degraded to 2-amino-3-(pyrimidin-5 -yl)propionic acid (461) (65JHCl>. 

Only the R(+) enantiomer of the herbicide 2-(2-methyl-4-chlorophenoxy)propionic acid was degraded (Tett et al. 1994), although cell extracts of Sphingomonas herbicidovorans grown with the R(-) or S -) enantiomer, respectively, transformed selectively the R -) or S(-) substrates to 2-methyl-4-chlorophenol (Nickel et al. 1997). 

Zipper C, M Bunk, AJB Zehnder, H-PE Kohler (1998) Enantioselective uptake and degradation of the chiral herbicide dichloroprop [(R5)-2-(2,4-dichlorophenoxy)propionic acid] by Sphingomonas herbicidov-orans MH. J Bacteriol 180 3368-3374. 

Zipper C, K Nickel, W Angst, H-PE Kohler (1996) Complete microbial degradation of both enantiomers of the chiral herbicide Mecoprop [(R,S)-2-(4-chloro-2-methylphenoxy)]propionic acid in an enantioselective manner by Sphingomonas herbicidovorans sp. nov. Appl Environ Microbiol 62 4318-4322. 

Tocopheryl)propionic acid (50) is one of the rare examples that the o-QM 3 is involved in a direct synthesis rather than as a nonintentionally used intermediate or byproduct. ZnCl2-catalyzed, inverse hetero-Diels-Alder reaction between ortho-qui-none methide 3 and an excess of <2-methyl-C,<9-bis-(trimethylsilyl)ketene acetal provided the acid in fair yields (Fig. 6.37).67 The o-QM 3 was prepared in situ by thermal degradation of 5a-bromo-a-tocopherol (46). The primary cyclization product, an ortho-ester derivative, was not isolated, but immediately hydrolyzed to methyl 3-(5-tocopheryl)-2-trimethylsilyl-propionate, subsequently desilylated, and finally hydrolyzed into 50. 

Biological. Degradation by the microorganism Nocardia rhodochrous yielded ammonium ion and propionic acid, the latter being oxidized to carbon dioxide and water (DiGeronimo and Antoine, 1976). When 5 and 10 mg/L of acrylonitrile were statically incubated in the dark at 25 °C with yeast extract and settled domestic wastewater inoculum, complete degradation was observed after 7 d (Tabak et al., 1981). Heukelekian and Rand (1955) reported a 5-d BOD value of 1.09 g/g which is 60.0% of the ThOD value of 1.81 g/g. 

Soil. Propanil degrades in soil forming 3,4-dichloroaniline (Bartha, 1968, 1971 Bartha and Pramer, 1970 Chisaka and Kearney, 1970 Duke et al., 1991) which degrades via microbial peroxidases to 3,3, 4,4 -tetrachlorazobenzene (Bartha and Pramer, 1967 Bartha, 1968 Chisaka and Kearney, 1970), 3,3, 4,4 -tetrachloroazooxybenzene (Bartha and Pramer, 1970), 4 (3,4-dichloroanilo)-3,3, 4,4 -tetrachloroazobenzene (Linke and Bartha, 1970), and l,3-bis(3,4-dichloro-phenyl)triazine (Plimmer et al., 1970), propionic acid, carbon dioxide, and unidentified products (Chisaka and Kearney, 1970). Evidence suggests that 3,3, 4,4 -tetrachloroazobenzene reacted with... 

These short-chain fatty acids are acetic, butyric, lactic and propionic acids, also known as volatile fatty acids, VFA. They are produced from fermentation of carbohydrate by microorganisms in the colon and oxidised by colonocytes or hepatocytes (see above and Chapter 4). Butyric acid is activated to produce butyryl-CoA, which is then degraded to acetyl-CoA by P-oxidation acetic acid is converted to acetyl-CoA for complete oxidation. Propionic acid is activated to form propionyl-CoA, which is then converted to succinate (Chapter 8). The fate of the latter is either oxidation or, conversion to glucose, via glu-coneogenesis in the liver. 

After 15 days of degradation only low amounts of degradation products have evolved, the amount being lower than the detection limit of the GC system. After 17 weeks, however, 2-butanol, propionic acid, 1-pentanol, but3nic acid, valeric acid and caproic acid were detected in pH 6 water fraction. After another 20 weeks several alkanes could also be detected n-octane, n-nonane, n-decane, n-dodecane, n-tridecane and n-tetradecane (13). 

This pathway is also important for ruminant animals, which are dependent on symbiotic microorganisms to break down their food. The microorganisms produce large amounts of propionic acid as a degradation product, which the host can channel into the metabolism in the way described. 

The degradation of nicotinic acid by Clostridium barkeri involves the cleavage of the intermediate 2,3-dimethylmalate 132 from which propionic and pyruvic acids are formed by a specific lyase (EC 4.1.3.32). In the reverse direction, the enzyme must have the unusual capacity to deprotonate propionic acid at the a-carbon instead of the carboxylic acid function, or next to an anionic car-boxylate. Purified dimethylmalic acid aldolase has been used to catalyze the stereospecific addition of 133 to the oxoacid acceptor, yielding the (2R,3S) configurated dimethylmalic acid 132 at the multi-gram scale [381]. The substrate tolerance of this enzyme has not yet been determined. 

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