Maleic anhydride Specifications

The general sales specification under which maleic anhydride is sold ia the United States specifies a white fused mass or briquettes of 99.5% minimum assay and 52.5°C minimum crystallisation poiat. The melt color specification is 20 APHA maximum with a maximum APHA color of 40 after two hours of heating at 140°C. Four grams of maleic anhydride ia 10 milliliters of water are to be completely soluble. The resulting solution is to be colodess. The acidity resulting from maleic acid is allowed to be a maximum of 0.2%. 

The test methods used by industry to determine if a sample of maleic anhydride is within specifications (165) ate ASTM methods D2930, D1493, and D3366. These methods describe procedures for the determination of maleic acid content, the crystallization point, and the color properties of the maleic anhydride sample, respectively. By quantitative deterrnination of these properties, a calculation of the overall purity of the maleic anhydride sample can be made. 

Fumaric acid and malic acid [6915-15-7] are produced from maleic anhydride. The primary use for fumaric acid is in the manufacture of paper siting products (see Papermaking additives). Fumaric acid is also used to acidify food as is malic acid. Malic acid is a particularly desirable acidulant in certain beverage selections, specifically those sweetened with the artificial sweetener aspartame [22839-47-0]. 

D3504-91, Standard Specifications for Maleic Anhydride," 1992MnnualBook ofMSTM Standards, Sec. 6, Vol. 06.03, ASTM, Philadelphia, Pa., 1992, p. 676. 

After separation of the catalyst by filtration, raw succinic anhydride is purified by distillation under reduced pressure, ie, 4—13 kPa (30—98 mm Hg), and flaked. The material of constmction of the plant is stainless steel. Typical specific consumptions for the production of one metric ton of succinic anhydride are maleic anhydride at 1050 kg hydrogen, 300 m steam, 4500 kg cooling water, 100 m electricity, 350 kW nitrogen, 100 m and methane,... 

The diene addition is stereochemically specific (22). Although two stereoisomers are possible, the endo and the exo forms, in the addition of maleic anhydride to CPD the endo adduct is the exclusive product (23). 

Common chemistries include tannins and lignins but also more modem polyacrylates and derivatives, which often act as carriers for specific functional groups and provide novel chemistry molecules. The polyacrylates may also be copolymerized, perhaps with maleates [maleic anhydride, cis-butenedioic anhydride (OCOCHrCHCO) is the usual starting point material], styrene (vinylbenzene, phenylethylene,... 

A pilot-scale rsactor that can produce 50 kg of GBL per one batch was designed. The reactor size was calculated on the basis of maleic anhydride conversion of 100% and GBL yield of 50%. By assuming the saturate liquid densily of reactant and product at the reaction conditions of 250 C and 70 atm undo- the condition of no solvent, the daisity and specific... 

A corrosion inhibitor with excellent film-forming and film-persistency characteristics is produced by first reacting Cig unsaturated fatty acids with maleic anhydride or fumaiic acid to produce the fatty acid Diels-Alder adduct or the fatty acid-ene reaction product [31]. This reaction product is further reacted in a condensation or hydrolyzation reaction with a polyalcohol to form an acid-anhydride ester corrosion inhibitor. The ester may be reacted with amines, metal hydroxides, metal oxides, ammonia, and combinations thereof to neutralize the ester. Surfactants may be added to tailor the inhibitor formulation to meet the specific needs of the user, that is, the corrosion inhibitor may be formulated to produce an oil-soluble, highly water-dispersible corrosion inhibitor or an oil-dispersible, water-soluble corrosion inhibitor. Suitable carrier solvents may be used as needed to disperse the corrosion inhibitor formulation. 

The reactivity of vanadyl pyrophosphate (VO)2P207, catalyst for n-butane oxidation to maleic anhydride, was investigated under steady and unsteady conditions, in order to obtain iirformation on the status of the active surface in reaction conditions. Specific treatments of hydrolysis and oxidation were applied in order to modify the characteristics of the surface layer of the catalyst, and then the unsteady catalytic performance was followed along with the reaction time, until the steady original behavior was restored. It was found that the transformations occurring on the vanadyl pyrophosphate surface depend on the catalyst characteristics (i.e., on the PfV atomic ratio) and on the reaction conditions. 

The industrial catalyst for n-butane oxidation to maleic anhydride (MA) is a vanadium/phosphoras mixed oxide, in which bulk vanadyl pyrophosphate (VPP) (VO)2P207 is the main component. The nature of the active surface in VPP has been studied by several authors, often with the use of in situ techniques (1-3). While in all cases bulk VPP is assumed to constitute the core of the active phase, the different hypotheses concern the nature of the first atomic layers that are in direct contact with the gas phase. Either the development of surface amorphous layers, which play a direct role in the reaction, is invoked (4), or the participation of specific planes contributing to the reaction pattern is assumed (2,5), the redox process occurring reversibly between VPP and VOPO4. 

Extension of the Kunii-Levenspiel bubbling-bed model for first-order reactions to complex systems is of practical significance, since most of the processes conducted in fluidized-bed reactors involve such systems. Thus, the yield or selectivity to a desired product is a primary design issue which should be considered. As described in Chapter 5, reactions may occur in series or parallel, or a combination of both. Specific examples include the production of acrylonitrile from propylene, in which other nitriles may be formed, oxidation of butadiene and butene to produce maleic anhydride and other oxidation products, and the production of phthalic anhydride from naphthalene, in which phthalic anhydride may undergo further oxidation. 

Trimethylsilyl azide is also a specific for conversion of maleic anhydrides to the biologically active oxazinedione ring systems. 

As a specific example of the vinylallenes, 294 demonstrates that not only can common dienophiles such as maleic anhydride (MA) be added (to furnish adduct 295 with a rich functionality) [122], but also carbonyl compounds such as propanal to afford 296 when the reaction is carried out in the presence of a Lewis acid catalyst [27]. 

In the present paper, we report on the compatibilization of clay with polyolefins, specifically low and high density poly-ethylenes (LDPE, HDPE), through the radical-induced polymerization of maleic anhydride (MAH) in the presence of the polymer and clay, so that the MAH is grafted on the PE and the anhydride groups concurrently react with the filler surface (l, 2). 

Vanadium phosphorus oxides (VPO) are commercially used as catalysts for the s5mthesis of maleic anhydride from the partial oxidation of n-butane. The phase constitution and the morphology of the catalyst are found to be dependent on the preparation routes and the applied solvent [78]. Recently, a method to prepare VPO catalysts in aqueous solution at elevated temperature was reported [79]. In addition to the linear relationship between specific activity and surface area, a small group of catalysts exhibit enhanced activity, which could be due to the combination of a higher proportion of V phases in the bulk of vanadyl pyrophosphate (V0)2P207 catalyst [79, 80]. With high relevance to the catalytic properties, the microstructure characterisation of VPO therefore is of great importance. 

An appropriate formalism for Mark-Houwink-Sakurada (M-H-S) equations for copolymers and higher multispecies polymers has been developed, with specific equations for copolymers and terpolymers created by addition across single double bonds in the respective monomers. These relate intrinsic viscosity to both polymer MW and composition. Experimentally determined intrinsic viscosities were obtained for poly(styrene-acrylonitrile) in three solvents, DMF, THF, and MEK, and for poly(styrene-maleic anhydride-methyl methacrylate) in MEK as a function of MW and composition, where SEC/LALLS was used for MW characterization. Results demonstrate both the validity of the generalized equations for these systems and the limitations of the specific (numerical) expressions in particular solvents. 

The Diels-Alder reaction is stereo specific. The stereochemistry of the dienophile is retained in the product i.e., cis and trans dienophiles produce different diastereoisomers in the product. For example, freshly distilled cyclopentadiene, having s-cis configuration, reacts with maleic anhydride to give c/ -norbornene-Sjh-endo-dicarboxylic anhydride. 

Molten maleic anhydride is shipped in tank rail cars, tank trucks and isotanks (for overseas shipments). Solid form maleic anhydride is produced from molten maleic anhydride as briquettes or pastille weighing 0.5 to 20 g. Fumaric acid is shipped in solid form, the particles size varying based upon the specification. 

For the copolymerization of epoxides with cyclic anhydrides and curing of epoxy resins, Lewis bases such as tertiary amines are most frequently used as initiators. In this case, terminal epoxides react with cyclic anhydrides at equimolar ratios. The time dependence of the consumption of epoxide and anhydride is almost the same for curing 35-36> and for model copolymerizations 39,40,45). The reaction is specific 39,40) to at least 99 %. In contrast, the copolymerization with non-terminal epoxides does not exhibit this high specificity, probably because of steric hindrances. The copolymerization of vinylcyclohexene oxide or cyclohexene oxide is specific only to 75-80 % and internal epoxides such as alkylepoxy stearates react with anhydrides only to 60-65 %. On the other hand, in the reaction of epoxy resins with maleic anhydride the consumption of anhydride is faster 65the products are discoloured and the gel is formed at a low anhydride conversion 39). Fischer 39) assumes that the other resonance form of maleic anhydride is involved in the reaction according to Eq. (33). 

Brault, L., Denance, M., Banaszak, E., Maadidi, S.E., Battaglia, E., Bagrel, D., and Samadi, M. (2007) Synthesis and biological evaluation of dialkylsubstituted maleic anhydrides as novel inhibitors of Cdc25 dual specificity phosphatases. European Journal of Medicinal Chemistry, 42, 243-247. 

The cytotoxic neocarzinostatin (NCS) is a small protein (Mw 12 kD) associated with a low molecular weight chromophore. NCS is rapidly cleared by the kidney and its cytotoxicity is non-cell specific. To modify its disposition, two poly(styrene-co-maleic acid anhydride) copolymers (Mw 1,500) have been coupled to one molecule of NCS, to give styrene-maleic-anhydride-neocarcinostatin (SMANCS) systems. 

This section shows, for four examples of increasing complexity, how precipitates are formed and how the properties of the precipitates are controlled to produce a material suitable for catalytic applications. The first two examples comprise silica, which is primarily used as support material and is usually formed as an amorphous solid, and alumina, which is also used as a catalytically active material, and which can be formed in various modifications with widely varying properties as pure precipitated compounds. The other examples are the results of coprecipitation processes, namely Ni/ AI2O3 which can be prepared by several pathways and for which the precipitation of a certain phase determines the reduction behavior and the later catalytic properties, and the precipitation of (VOjHPCU 0.5 H2O which is the precursor of the V/P/O catalyst for butane oxidation to maleic anhydride, where even the formation of a specific crystallographic face with high catalytic activity has to be controlled. 

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