3- -3-hydroxypropionic

Hydroxypropionic acid is an uncrystallizable and hygroscopic sirup. The 20-25 Pcr cent °f impurity remaining in the final product is largely water. 

Figure 15.3 3-Hydroxypropionate (3HP) synthesis via glycerol-dependent, malonyl-CoA-dependent, and p-alanine-dependent pathways. Gene symbols are ppc, phosphoenolpyruvate carboxylase aspC, aspartate...

P-Hydroxy acids lose water, especially in the presence of an acid catalyst, to give a,P-unsaturated acids, and frequendy P,y-unsaturated acids. P-Hydroxy acids do not form lactones readily because of the difficulty of four-membered ring formation. The simplest P-lactone, P-propiolactone, can be made from ketene and formaldehyde in the presence of methyl borate but not from P-hydroxypropionic acid. P-Propiolactone [57-57-8] is a usehil intermediate for organic synthesis but caution should be exercised when handling this lactone because it is a known carcinogen. 

Contaminants and by-products which are usually present in 2- and 4-aminophenol made by catalytic reduction can be reduced or even removed completely by a variety of procedures. These include treatment with 2-propanol (74), with aUphatic, cycloaUphatic, or aromatic ketones (75), with aromatic amines (76), with toluene or low mass alkyl acetates (77), or with phosphoric acid, hydroxyacetic acid, hydroxypropionic acid, or citric acid (78). In addition, purity may be enhanced by extraction with methylene chloride, chloroform (79), or nitrobenzene (80). 

Potassium permanganate oxidizes succinic acid to a mixture of malic and tartaric acid [133-37-9]. 3-Hydroxypropionic acid [503-66-2] is obtained with sodium perchlorate. Cerium(IV) sulfate in sulfuric acid medium oxidizes succinic acid to oxaloacetic acid (71). 

Chemical Designations - Synonyms 2-Hydroxypropanoic acid alpha-Hydroxypropionic acid Milk acid Racemic acid Chemical Formula CHjCHOHCOOH-HjO. 

Chemical Reactivity - Reactivity with Water A slow, non-hazardous reaction occurs forming beta-hydroxypropionic acid Reactivity with Common Materials No reactions Stability During Transport Stable Neutralizing Agents for Acids and Caustics Not pertinent Polymerization Can polymerize and rupture containers especially at elevated temperatures. At 22 °C, approximately 0.04 % polymerizes per day Inhibitor of Polymerization None reported in the literature. 

The catalyst is a cobalt carbonyl that is prepared in situ from cobaltous hydroxide, and nonylpyridine is the promotor. Oxidation of the aldehyde produces 3-hydroxypropionic acid. 1,3-Propanediol and 3-hydroxypropi-onic acid could also be produced from acrolein (Chaper 8). ... 

CoSANSE = [bis(salicylidene-N-(methyl-3>hydroxypropionate))] Co Punniyamurthy, T. Iqbal. J. Tetrahedron Lett., 1994, 35, 4007... 

There are two pathways for the degradation of nitriles (a) direct formation of carboxylic acids by the activity of a nitrilase, for example, in Bacillus sp. strain OxB-1 and P. syringae B728a (b) hydration to amides followed by hydrolysis, for example, in P. chlororaphis (Oinuma et al. 2003). The monomer acrylonitrile occurs in wastewater from the production of polyacrylonitrile (PAN), and is hydrolyzed by bacteria to acrylate by the combined activity of a nitrilase (hydratase) and an amidase. Acrylate is then degraded by hydration to either lactate or P-hydroxypropionate. The nitrilase or amidase is also capable of hydrolyzing the nitrile group in a number of other nitriles (Robertson et al. 2004) including PAN (Tauber et al. 2000). 

Ansede JH, PJ Pellechia, DC Yoch (1999) Metabolism of acrylate to 3-hydroxypropionate and its role in dimethylsulfoniopropionate lyase indnction by a salt march sediment bacterium, Alcaligenes faecalis M3 A. Appl Environ Microbiol 65 5075-5081. 

With 3-hydroxypropionic or 4-hydroxybutyric acid very little or no phosphor diester bond formation occurred. 1753... 

Besides 3HB, several other HASCL are incorporated into PHAs. This includes 3-hydroxypropionate (3HP),3-hydroxyvalerate (3HV), 4-hydroxybutyrate (4HB), 4-hydroxyvalerate (4HV), and 5-hydroxyvalerate (5HV). With only few exceptions these constituents are only incorporated into PHAs if precursor substrates are provided, and most of these polyesters cannot be synthesized from simple, structurally unrelated carbon sources. 

Ethyl a-bromoisobutyrate, 21, 53 Ethyl /3-bromopropionate, 20, 6S Ethyl caprylate, 20, 69 Ethyl carbonate, 23, 95, 97 Ethyl chlorocarbonate, 21, 81 2-Ethylchromone, 21, 42 Ethyl diacetylacetate, 21, 46 copper derivative, 21, 46 Ethyl a,a-DIMETHYL-/3-PHENYL-/3-hydroxypropionate, 21, S3 Ethylene chloride, 20, 28 22, 76 ETHYLENEDIAMINE, IV IV-DIBUTYL-, 23, 23... 

Ethyl hexyl ketone, nlOO Ethyl hydrogen adipate, el77 /V-Ethyl-/V-(2-hydroxyethyl)-3-toluidine, e267 Ethyl 2-hydroxy-2-methylpropanoate, el82 Ethyl 2-hydroxypropionate, el94 Ethylidene bromide, d96... 

Tao J, McGee K (2002) Development of a continuous enzymatic process for the preparation of (R)-3-(4-fluorophenyl)-2-hydroxypropionic acid. Org Process Res Dev 4 520-524... 

Ethyl l-iodopropionate,/from ethyl 1-hydroxypropionate, methyl iodide, and triphenyl phosphite, Al, 47 Ethyl 4-methyl-E-4,8-non-... 

Microorganisms have also been developed to produce alternative products, such as lactic acid [65], propane-1,3-diol [67], 3-hydroxypropionic acid [68], butane-2,3-diol [69] and numerous other intermediates. For instance, bacteria such as the Clostridium acetobutylicum ferment free sugars to C4 oxygenates such as butyric acid or butanol. They form the C4 oxygenates by Aldol condensation of the acetaldehyde intermediates. The Weizmann process exploits this property to ferment starch feedstock anaerobically at 37 °C to produce a mixture of w-butanol, acetone and ethanol in a volume ratio of 70 25 5 [3],... 

Hydroxypropionic acid obtained by fermentation from glucose could also be a good candidate to produce various chemicals by catalytic routes [25]. 

This procedure describes an efficient method for the synthesis of >99% enantiomerically pure ethyl glycidate from L-serine. Although preparation of potassium glycidate via cyclization of 3-bromo-2-hydroxypropionic acid,2 and from 3-chloro-2-hydroxypropionic acid (obtained by microbial reduction of chloropyruvic acid)3 was previously reported, the corresponding ethyl ester was never described. An enantioselective synthesis of the 2,3-epoxy acid by oxidation of 2,3-epoxypropanol has also been reported.4... 

---