Ketomalonic acid

Acrylamide - N, N -methylenebisacrylamide N-vinyl pyrrolidone - N, N -methylenebisacrylamide Fumaric acid/polyethylene glycol - N-vinyl pyrrolidone Fumaric acid/diglycolic acid - N-vinyl pyrrolidone Fumaric acid/ketomalonic acid - N-vinyl pyrrolidone Fumaric acid/ketoglutaric acid - N- vinyl pyrrolidone... 

Also on a PtBiCe02/C catalyst, ketomalonic acid is formed in a consecutive way from glycerol, followed by its anionic polymerization into polyketomalonate (Scheme 11.10), a polyether polymer with a MW of about 9000 and a polydisper-sity index of 1.04 [79]. 

In presence of 3 equivalents of oxidant, TEMPO mediates then the rapid conversion into ketomalonic acid. The pH of the reaction medium is critical at pH 7 no reaction occurs, while at high alkalinity TEMPO+ undergoes basic dismuta-tion. At pH 10, even the immobilized catalyst is stable and can be used during several subsequent reactions [95]. 

The reaction of 02 with ketomalonic acid leads to oxalic peracid and C02 [Schuchmann et al. 1991 reactions (72)—(74)]. 

The solution frequently becomes warm,12 and its refractive index,1 viscosity,2 freezing point-composition curve,3 and ultraviolet absorption spectrum 36 are not those which would be expected if no reaction took place. Usually hydrates or hemiacetals of simple aldehydes are too unstable to be isolated, but a number of them are actually known and their physical properties have been determined.4 When the carbonyl group is attached to an electron-attracting group (making the carbonyl carbon atom abnormally positive), stable hydrates are frequently formed. Glyoxal, chloral, and ketomalonic acid are common examples. 

Mesoxalic acid (or ketomalonic acid) is a good chelating agent and potentially a valuable synthon for organic synthesis. It has been prepared by oxidation of sodium tartronate on PtBi/C catalyst at 60 °C without pH control the maximum yield was 65% at 80% conversion [67]. Operating at 80 °C, 50% mesoxalic acid was obtained at total conversion of tartronic acid. The solution was free from other oxidation products, which were totally oxidized to CO2. 

Calcium Mesoxalate, Mcsorslir acid caldum salt calcium ketomalonate calcium oxomalonate ketomalonic acid calcium salt oxomalonic acid calcium salt Mesoxan. CjCaOs mol wt 156.11. C 23,08%, Ca 25.677°, O 51.257°. Prepn Scheiber, Hopfer, Ber. 53, 908 (1920) Kobayashi, Japan, pat. 4157( 52), CA, 48, 5212a (1954) Yanagisawa, Japan, pat. 7463( 60), C.A. 55, 5880a (1961). 

Short-chain organic acids such as formic, acetic, oxalic, glyoxylic, pyruvic, and ketomalonic acid are formed as by-products in drinking water treatment plants employing ozone. Reasons for... 

Ciriminna, R. M. Pagliaro. One-pot homogeneous and heterogeneous oxidation of glycerol to ketomalonic acid mediated by tempo. Adv. Synth. Catal. 2003,345, 383-388. 

Sometimes the products of carbonyl compounds silylation are not TMS-enols, but bis-TMS derivatives of hydrated carbonyls, RR C = 0 RR C(OH)2 RR C(OTMS)2. More unpredictable products can be formed during silylation of a-ketocarboxylic acids. For example, ketomalonic acid (II) besides the normal bis-JMS ester gives an unusual TMS derivative of the enol-hydrate form (see Fig. 7). 

Fig. 7 Example of unusual silylation of ketomalonic acid with formation of tetrakis-TMS derivative instead of normal ester.

By a selective oxidation of glycerol, valuable products such as glyceric acid, tartronic acid, or ketomalonic acid can be formed. This reaction is commonly done by using Pd or Pt particles on a carbon support in the presence of dioxygen under basic conditions [215-220]. 

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