Maleic acid CAS

Maleic anhydride CAS. 108-3I-6. til, maleic acid [CAS 110-16-7]. (2), and I umarie acid [CAS 110-17-81. i3) are multifunctional chemical intermediates that lind applications in nearly every Held id industrial chemistry. Each molecule contains two acid carbonyl groups and a double bond in the u. position. Maleic anhydride and maleic acid are important raw materials used in the manufacture of phthalic-type alkyd and polyester resins, surface coatings, lubricant additives, plasticizers. copolymers, and agricultural chemicals [see Alkyd Resins Polymers, and Lubricant). Both chemicals derive their common names from naturally occurring malic acid. 

Although pH is a convenient measure of acidity in paper, it is not the same as the concentration of acid in the paper. In a heterogenous material such as paper, the molar concentration of hydrogen ions is not an easily defined quantity (12). Nevertheless, since the buffer system [maleic acid/Ca(OH)2] in the paper is the primary factor controlling the acid content of the paper, one might expect the cold extraction pH to reflect an effective acid concentration. This effective acid concentration can be expressed as shown in Equation 5. Values of [H+] were calculated from... 

The H NMR spectra of formic acid (HCO2H), maleic acid (cA-H02CCH=CHC02H), and malonic acid (HO2CCH2CO2H) are similar in that each is characterized by two... 

Competitive inhibitors bind to specific groups in the enzyme active site to form an enzyme-inhibitor complex. The inhibitor and substrate compete for the same site, so that the substrate is prevented from binding. This is usually because the substrate and inhibitor share considerable stmctural similarity. Catalysis is diminished because a lower proportion of molecules have a bound substrate. Inhibition can be relieved by increasing the concentration of substrate. Some simple examples are shown below. Thus, sulfanilamide is an inhibitor of the enzyme that incorporates j9-aminobenzoic acid into folic acid, and has antibacterial properties by restricting folic acid biosynthesis in the bacterium (see Box 11.13). Some phenylethylamine derivatives, e.g. phenelzine, provide useful antidepressant drags by inhibiting the enzyme monoamine oxidase. The cA-isomer maleic acid is a powerful inhibitor of the enzyme that utilizes the trans-isomer fumaric acid in the Krebs cycle. 

N 8.80% crysts (from ale), mp 78.5—79° sol in benz, toluene, dioxane acetone insol in w benzin. Its prepn was patented by C.J. Mighton [USP 2365717(1944) CA 39, 4627(1945)] thru heating of maleic acid anhydride 2-nitro-2-methyl-l-propanol in the presence of p-toluenesulfonic acid (Ref 2) It was found to be a suitable plasticizer of NC when It was desired to obtain flexihle solvendess rolled sheet propellants (Ref 3) Refs . 1) Beil 2, 19251 [Di( methylpropyl) maleate] 2) Beil 2, ]l925i [Di( 2-nitro-2-methylpropyl)-maleate] 3) Anon, Summary-TechRept of Div 8, NDRC, Vol -1(1946), pi 19... 

BA BuE-PA BE-HET BE-HHPA BE-MA BE-PA BE-SA CA CHX DMA DMBA DY 062 GA HEB HHPA HMTA MA MTHPA NMA benzoic acid monobutylester of phthalic acid monobenzylester of hexachloroendomethylenetetrahydrophthalic acid monobenzylester of hexahydrophthalic acid monobenzylester of maleic acid monobenzylester of phthalic acid monobenzylester of succinic acid citraconic anhydride cyclohexanol N,N-dimethylaniline dimethylbenzylamine high boiling tertiary amine (Ciba Geigy AG) gjptaric anhydride 2-hydroxy-4-(2,3-epoxypropoxy)benzophenone hexahydrophthalic anhydride hexamethylenetetramine maleic anhydride methyltetrahydrophthalic anhydride nadic methyl anhydride (methylbicyclo[2.2.1]heptene-2,3-dicarboxylic anhydride isomers)... 

Prior to high-performance liquid chromatography (HPFC), samples were filtered through a 0.2-gm pore size mixed cellulose ester filter (Schleicher Schuell, Dassel, Germany). Buffer components such as acetic acid, citric acid, maleic acid, and succinic acid were separated on an Aminex HPX-87H (Bio-Rad, Hercules, CA) organic acid column at 65°C using a... 

The ethyl acetate solution containing aminosulfonamide (ca. 27.9 g, 86 mmol 95 5 trans/cis) from step 5 was concentrated by distillation (1 atm) to a volume of 70 mL. Acetone (250 mL) was added and the concentration repeated to a volume of 70 mL. The operation was repeated, this time concentrating to a volume of 160 mL. Maleic acid (9.98 g, 86 mmol) was added. The mixture was stirred until the salt crystallized, and was then stirred for 12-18 h at 20°-22°C. The mixture was filtered, and the product cake washed with acetone (1 bed volume). The product was air-dried, then dried in vacuo (100 mBar, nitrogen sweep, 75°C) to constant weight. Yield 33.0 g (92%) of the maleate salt as a white crystalline solid. HPLC 99 1 trans/cis (above method). 

Hsiou, Y., Wang, Y. and Liu, L.-K. (1989). Structures of tetracarbonyl (2-3-r -maleic acid)iron, cA-[Fe(C4H404)(C0)4], and tetracarbonyl (2-3-r -fumaric acid)iron, trara-[Fe(C4H404)(C0)4]. Acta Crystallogr. C45,... 

Control of Acidity. The acidities of the paper samples were controlled with buffers containing various formal ratios of maleic acid to calcium hydroxide. A series of aqueous solutions of 1.3 X 10"2F Ca(OH)2 was prepared. Maleic acid was added to each solution to achieve formal ratios ranging from zero to five. Paper samples, demineralized in dilute... 

H ion binding to the linear polyion. A similar pattern of protonation has recently been reported for spedlied polyions with carboxylate groups, i.e., polymers of maleic acid and fomaric acid, whose distance between the adjacent carboxylate groups is as short as ca. 2 A [76]. 

CAS 15535-69-0. [(C4H9)2Sn(OOCCH)2]3. Properties White, amorphous powder. Mp 110C, flash p 400F (204C). Insoluble in water soluble in benzene and organic esters. Combustible. Derivation Reaction of maleic acid with di-butyltin oxide. 

The rate constants do not vary significantly from pH 3.5 to 7.0, but no reaction occurs at pH 2 or 13. The sulfonation rates increase with ionic strength. With fumaric and maleic acids, there may also be an additional catalytic effect of Mg" " or Ca"1-1". 

RuC12(TPPMS)2]2 is an active catalyst for the hydrogenation of water-soluble al-kenes, such as maleic, fumaric, and crotonic acids, in aqueous solutions [26]. A thorough kinetic study of crotonic acid (CA) hydrogenation was undertaken. The rate law derived is given by Eq. (16) ... 

In stationary solution, the dissolution of calcite in aqueous maleic acid occurs via the formation of characteristically shaped etch pits. Plates 3 and 4 show etch pits obtained by employing 3mM aqueous maleic acid which, unbuffered, gives rise to a 1 1 solution in H+ and the monoanion, HA (pA j ca. 1.52). Etching times were 15 and 120 min, respectively. 

---