Maleate fumaric acid

Oxidation. Maleic and fumaric acids are oxidized in aqueous solution by ozone [10028-15-6] (qv) (85). Products of the reaction include glyoxyhc acid [298-12-4], oxalic acid [144-62-7], and formic acid [64-18-6], Catalytic oxidation of aqueous maleic acid occurs with hydrogen peroxide [7722-84-1] in the presence of sodium tungstate(VI) [13472-45-2] (86) and sodium molybdate(VI) [7631-95-0] (87). Both catalyst systems avoid formation of tartaric acid [133-37-9] and produce i j -epoxysuccinic acid [16533-72-5] at pH values above 5. The reaction of maleic anhydride and hydrogen peroxide in an inert solvent (methylene chloride [75-09-2]) gives permaleic acid [4565-24-6], HOOC—CH=CH—CO H (88) which is useful in Baeyer-ViUiger reactions. Both maleate and fumarate [142-42-7] are hydroxylated to tartaric acid using an osmium tetroxide [20816-12-0]/io 2LX.e [15454-31 -6] catalyst system (89). 

The effect is very pronounced, but falls off sharply as soon as the carboxyl groups are separated by more than one saturated carbon atom. C/ s-butenedioic(maleic) acid (5, pKal = 1-92) is a much stronger acid than trans-butenedioic(fumaric) acid (6, pX,1 = 3-02), due to the intramolecular hydrogen bonding that can take place with the former, but not with the latter, leading to relative stabilisation of the cis (maleate, 7) mono-anion (cf. o-hydroxybenzoic acid above) ... 

Ethyl fumarate has been prepared from fumaric acid and ethyl alcohol, with or without sulfuric acid as catalyst,4 from silver fumarate and ethyl iodide,5 from silver maleate and ethyl iodide plus a trace of iodine,6 from ethyl maleate by the action of iodine,6 from ethyl maleate and phosphorus pentachloride,7 and by passing hydrogen chloride into a boiling absolute alcohol solution of malic acid.8... 

The cycloaddition of allenes to symmetrically disubstituted alkenes gives mixtures of cyclobutanes with stereochemical equilibration of the substituents. The reaction of 1,3-dimethylallenc with either diethyl fumarate or diethyl maleate produces a mixture of the /raw.v-bis(ethoxycar-bonyl)cyclobutanes.s The same nonstereoselectivity was observed for phenylallene and 1,1-dimelhylallene cycloadditions to maleic and fumaric acid diesters.9 10... 

Hydroformylation - [CARBON MONOXIDE] (Vol 5) - [OXO PROCESS] (Vol 17) -of allyl alcohol [ALLYL ALCOHOL AND MONOALLYL DERIVATIVES] (Vol 2) -catalysts for [CATALYSIS] (Vol 5) -C-19 dicarboxylic acids from [DICARBOXYLIC ACIDS] (Vol 8) -of ethylene [ETHYLENE] (Vol 9) -of ethylene [PROPYL ALCOHOLS - N-PROPYLALCOLHOL] (Vol 20) -of maleate and fumarate esters [MALEIC ANHYDRIDE, MALEIC ACID AND FUMARIC ACID] (Vol 15) -phosphine catalyst [PHOSPHORUS COMPOUNDS] (Vol 18) -platinum-group metal catalysts for [PLATINUM-GROUP METALS] (Vol 19) -rhodium catalysis [PLATINUM-GROUP METALS, COMPOUNDS] (Vol 19) -ruthenium cmpds or catalyst [PLATINUM-GROUP METALS, COMPOUNDS] (Vol 19) -use of coordination compounds [COORDINATION COMPOUNDS] (Vol 7)... 

The crude fumaric acid is from 74-78 per cent pure as found by titration with standard alkali. The only impurity present besides inorganic salts consists of small quantities of sodium hydrogen maleate which is decomposed by the hydrochloric acid during the purification process. 

Typical acyclic olefins of symmetrically substituted types are the esters of maleic and fumaric acids. Though maleimides and maleates are both symmetrical cis-olefins, these two exhibit quite different stereoselectivity in cycloadditions to azomethine ylides. There are relatively limited examples known for the stereoselective cycloadditions of azomethine ylides to symmetrical acyclic olefins. These stereoselective cycloadditions are listed in Table IX, and nonstereoselective reactions in Table X. 

Smaller organic anions Amino acids, alkane caiiwxylic acids (formate, acetate, propionate, butyrate), chloro carboxylic acids (chloroacetate, dichloroacetate), hydroxy acids (hydroxyacetate, lactate, tartrate, citrate), glycolate, gluconate, pyruvate, dicarboxylic acids (oxalate, malonate, succinate, glutarate, fumarate, maleate), alkanesulfonic acids (methanesulfonate, ethanesulfonate). 

Such perfect cases of equilibration are rare. Another important one concerns equilibration by Michael addition to conjugated alkenes. A classic case is the preparation of maleate 47 and fumarate 48 esters from (the necessarily Z-) maleic anhydride 46. Simple treatment with methanol in acidic solution gives the liquid maleate 47 as expected. It is unusual for cis and trans alkenes to be given different names maleic and fumaric acids were named before their relationship was understood. 

Since maleic acid is a cheaper starting material than fumaric acid, the process that is probably the most economical makes use of both a maleate isomerase (E. C. 5.2.1.1) and aspartase (E.C. 4.3.1.1), Scheme 12.6-1. Mitsubishi has succeeded in... 

The effects of dicarboxylate [R(COONa)2] ions on the PNO-catalyzed IPTC reactions of PhCOCl and sodium dicarboxylates in H2O/CH2CI2 medium were investigated on selected dicarboxylate ions including oxalate, malonate, maleate, fumarate, succinate, adipate, nonanedioate, phthalate, isophthalate, and terephthalate [190]. In general, the observed products included mono- and bis-(benzoyloxycarbonyl) compounds, benzoic anhydride, and benzoic acid, which depended on the molecular structure of the dicarboxylate ion. Four types of dicarboxylate ions were classified according to the distribution of products shown as follows ... 

The diallyl esters of maleic and fumaric acid have found application primarily in copolymer systems. Considering that the distance between the two allyl groups of the maleate ester is similar to those of the o-phthalate, and that of the fumarate is geometrically quite different, it is unfortunate that there seems to have been no study of the cyclopolymerization possibilities of these monomers. In addition there are the problems associated with the copolymerization of an allyl grouping with the double bond of the maleic or fumaric moieties within the same molecule. 

Butenedioic acid. See Fumaric acid cis-Butenedioic acid. See Maleic acid (E)-Butenedioic acid trans-Butenedioic acid. See Fumaric acid (Z)-Butenedioic acid. See Maleic acid 2-Butenedioic acid bis (2-ethylhexyO ester. See Dioctyl fumarate 2-Butenedioic acid (Z)-, bis (2-ethylhexyO ester. See Bis (2-elhylhexyl) maleate... 

It might be expected that it would be possible to determine the degree of cure by monitoring the concentration of residual maleic anhydride/fumaric acid, detected as dimethyl maleate in the THM procedure. 

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