Fumaric acid salt

Palladium on carbon (10%, 0.10g) was added to a solution of the Step 4 product (2.0 mmol) in methyl alcohol and stirred 18 hours at room temperature under a hydrogen atmosphere. The mixture was filtered through a filter aid, concentrated, and the residue isolated in 96% yield. The residue was converted into the fumaric acid salt and crystallized from methyl alcohol/diethyl ether and the product isolated as a colorless solid, mp = 150-152°C. 

Additives acting on the pour point also modify the crystal size and, in addition, decrease the cohesive forces between crystals, allowing flow at lower temperatures. These additives are also copolymers containing vinyl esters, alkyl acrylates, or alkyl fumarates. In addition, formulations containing surfactants, such as the amides or fatty acid salts and long-chain dialkyl-amines, have an effect both on the cold filter plugging point and the pour point. 

Description of Method. Salt substitutes, which are used in place of table salt for individuals on a low-sodium diet, contain KCI. Depending on the brand, fumaric acid, calcium hydrogen phosphate, or potassium tartrate also may be present. Typically, the concentration of sodium in a salt substitute is about 100 ppm. The concentration of sodium is easily determined by flame atomic emission. Because it is difficult to match the matrix of the standards to that of the sample, the analysis is accomplished by the method of standard additions. 

Argininosuccinic acid [2387-71-5] M 290.3, [a]p +16.4 (H2O). Likely impurity is fumaric acid. In neutral or alkaline soln it readily undergoes ring closure to the anhydride . Crystd from water by adding 1.5 vols of EtOH. Barium salt is stable at 0-5 if dry. [Westfall Biochem J 77 135 I960.]... 

Examples of polyfunctional carboxylic acids esterified by this method are shown in Table I. Yields are uniformly high, with the exception of those cases (maleic and fumaric acids) where some of the product appears to be lost during work-up as a result of water solubility. Even with carboxylic acids containing a second functional group (e.g., amide, nitrile) which can readily react with the oxonium salt, the more nucleophilic carboxylate anion is preferentially alkylated. The examples described in detail above illustrate the esterification of an acid containing a labile acetoxy group, which would not survive other procedures such as the traditional Fischer esterification. 

The sodium salt of phosphoric acid, sodium phosphate (NaH2P04), is weakly acidic, and is used with sodium bicarbonate to make baking powders. Other acids used in baking powder are fumaric acid and tartaric acid. 

Buffers are necessary to adjust and maintain the pH. Buffering agents can be salts of a weak acid and a weak base. Examples are ammonium, potassium, sodium carbonates (caustic soda), bicarbonates, and hydrogen phosphates [1345]. Weak acids such as formic acid, fumaric acid, and sulfamic acid also are recommended. Common aqueous buffer ingredients are shown in Table 17-8. 

Anodic oxidation of 1,2-dicarboxylic acids as their alkali metal salts in concentrated aqueous solution gives the alkene with the loss of two molecules of carbon dioxide [125]. Succinic acid affords etltene and methylsuccinic acid ptopene [50]. Allene is obtained from itaconic acid and the isomeric methylmaleic and methyl-fumaric acids give propyne... 

Particularly rapid are the quantitative salt formations of gaseous ammonia with 2-furancarboxylic (24), 2-furylacrylic (25), and 3,4-furandicarboxylic acid (26), and maleic (27) or fumaric acid (28) (bis-ammonium salts) (Scheme 3). Applications in removal of ammonia from atmospheric gases appear promising [22,28]. 

Sodium metal was dissolved in ethylene glycol and a solution of 37 in toluene was added. The mixture was heated at 100 °C and a 98% yield of the free base 3 was obtained. The free base was treated with fumaric acid in ethanol and 3 was isolated as the crystalline fumarate salt in 85% yield. 

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. 

The main drawback in the use of fumaric acid is its slow solubility rate in compar ison with citric acid, and special methods need to be employed in its dissolution. It has been claimed that fumaric acid and its salts have a tendency to stabilise the suspended matter in both flash-pasteurised and frozen fruit concentrates (McColloch Gentile, 1958). 

L-Malic acid (HOOC CH2 CHOH COOH) for use in the pharmaceutical industry is manufactured by conversion of fumaric acid by the intracellular enzyme fumarase produced by various microorganisms. The excess fumaric acid is easily separated by crystallization after concentration of the mother solution. Further addition of lime allows malic acid to be separated as calcium malate within a bioreactor crystallizer system. By adding diluted sulfuric or oxalic acid, the salt is split into free malic acid and calcium sulfate or oxalate, the latter being removed by filtration (Mourgues et al., 1997). 

The products were combined, dissolved in methanol (20 ml) and the solution and treated with a solution of fumaric acid (2.73 g) in methanol (50 ml). Absolute ether was added to precipitate the salt which was collected by filtration and recrystallized from methanol-water (200 20) with isopropyl ether added to the point of incipient cloudiness. The recrystallized salt (5.38 g) melted at 223°-225°C. 

Complexes. The iodine complexes of 1,5-naphthyridine and other heterocycles have been used under anhydrous conditions to estimate the pK.t values for such heterocycles.885 The structures of 1 1 complexes of 1,5-naphthyridine with oxalic acid,1024 fumaric acid,1024 or meso- 1,2-diphenyl- 1,2-ethane-diol1021 have been studied. Complexes of 1,5-naphthyridine with Co(II), Ni(II), Cu(II), Zn(II), and Ag(I) salts have been prepared 705 the mono- and... 

Expansion by means of azodicarbonamide and associated metal salt activators was mentioned earlier many substances have been suggested for use as inhibitors for such systems, their mode of action typically being to raise the temperature of decomposition of the blowing system and hence reduce the volume and speed of evolution of gas. Some inhibitors act by neutralizing metal salt activators so that they no longer have the effect of reducing the temperature of decomposition. Examples of this type include fumaric acid, trimellitic anhydride, and benztriazole. Others react with the azodicarbonamide and transform it into a different compound substantially resistant to the activation thiourea is an example of this type. Inhibition in these different forms is exemplified in Figure 110. 

While these experiments stimulated other research, it is sad to relate that the proposed explanation is not correct. It required almost seventy years, however, before it was realized that the curare-like action of the onium salts was a result of their ionic character. Other examples of the role of spatial arrangement were discovered. For example, quoting Stewart Ishizuka (1897) found that maleic acid was a much stronger poison than its stereoisomer, fumaric acid 1.94 grammes for every kilogramme in a dog s weight was a fatal dose of the former acid, while the same dose of fumaric acid was harmless. Similarly these isomers were found to have differential effects on microorganisms. Stewart also rationalized the mydriatic action of tropine and the inactivity of pseudotropine in terms of three-dimensional formulae as shown below (1 and 2). In many ways, these structural representations are close to the present-day conformational structures (pseudotropine = 3, tropine = 4) ... 

Although (maleic acid)Fe(C0)4 has a symmetry plane perpendicular to the plane of the double bond, (fumaric acid)Fe(C0)4 is clearly asymmetric and should thus be capable of resolution into its enantiomers (457). Accordingly, addition of the complex to a solution of brucine in acetone and crystallization of the diastereoisomeric salts followed by decomposition with hydrochloric acid yielded the two enantiomers having optical activities [a]ff —593 (acetone C, 0.848) and [a] f - -587 (acetone C, 0.921). Analyses and infrared spectra of individual enantiomers were identical to those of the racemic mixture. 

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