Maleic anhydride treatment

Reaction of acetic anhydride with (typical wood fiber) OH groups forms an ester bond and acetic acid is formed as a by-product. Reaction without catalyst was conducted at 70°C [33]. It is known that the rate of reaction is promoted by wood-swelling agents such as pyridine that can be used only at laboratory scale. The improved dimensional stability of wood as a result of anhydride modification has been found to be a function of weight percentage gain (WPG) only, regardless of the anhydride used for modification. 

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Roussel, C., Marchetti, V., Lemor, A., Wozniak, E., Loubinoux, B. and Gerardin, P. (2001). Chemical modification of wood by polyglycerol/maleic anhydride treatment. Holzforschung, 55(1), 57-62. 

Sulfonation was next examined as an alternate method of introducing ionic substituents. In both maleic anhydride treatment and sulfonation, the acidic substituents were neutralized with basic oxides such as calcium or magnesium. This step was usually necessary to prevent the loss of adhesion to the aggregate in the presence of water, except when the aggregate itself insolubilized the acidic components (for example, limestone ). 

The starting material is made by a photochemical [2 + 2] cycloaddition of acetylene and maleic anhydride. Treatment with butanol and base gives the monoester because, after butanol has attacked once, the product is the anion of a carboxyhc acid and cannot be attacked again by the nucleophile. 

Gaylord evaluated various clays in polyethylene using peroxide/maleic anhydride treatments [18]. He found very variable results, largely influenced by the nature of the clay surface, and concluded that some filler surfaces could actually inhibit the free radical grafting processes. 

Maleic anhydride treatment This is one of the most commonly used coupling agents to strengthen the composites with natural fibers and nonpolar polymers. The economic manufacturing and application of these coupling agents are described in detail in literature [29]. Mechanical properties of the composites increase as the... 

In another smdy with wood flour-polyethylene composite, maleic anhydride treatment of the filler resulted in 50% increase in tensile strength and 40% increase in flexural strength compared to their controls [33]. 

Auxiliary agents silane maleic anhydride treatment of saw dust" ... 

Acid Chloride Formation. Monoacid chlorides of maleic and fumaric acid are not known. Treatment of maleic anhydride or maleic acid with various reagents such as phosgene [75-44-5] (qv), phthaloyl chloride [88-95-9] phosphoms pentachloride [10026-13-8] or thionyl chloride [7719-09-7] gives 5,5-dichloro-2(5JT)furanone [133565-92-1] (4) (26). Similar conditions convert fumaric acid to fumaryl chloride [627-63-4] (5) (26,27). NoncycHc maleyl chloride [22542-53-6] (6) forms in 11% yield at 220°C in the reaction of one mole of maleic anhydride with six moles of carbon tetrachloride [56-23-5] over an activated carbon [7440-44-4] catalyst (28). 

Maleic anhydride is decomposed in the Hquid phase by various nitrogen bases. Treatment of maleic anhydride in refluxing acetic acid with 2-anainopyridine [504-29-0] gives, after work-up in 4 at 100°C, the decarboxylative dimeri2ation product, 2,3-dimethylmaleic anhydride [766-39-2]... 

Esterification. Both mono- and dialkyl maleates and fumarates are obtained on treatment of maleic anhydride or its isomeric acids with alcohols or alkoxides (25). An extensive review is available (59). Alkyl fumarates (18) often are made from isomeri2ation of the corresponding maleate (19) (60). 

Isomerization. Maleic acid is isomerized to fumaric acid by thermal treatment and a variety of catalytic species. Isomerization occurs above the 130 to 140°C melting point range for maleic acid but below 230°C, at which point fumaric acid is dehydrated to maleic anhydride. Derivatives of maleic acid can also be isomerized. Kinetic data are available for both the uncatalyzed (73) and thiourea catalyzed (74) isomerizations of the cis to trans diacids. These data suggest that neither carbonium ion nor succinate intermediates are involved in the isomerization. Rather, conjugate addition imparts sufficient single bond character to afford rotation about the central C—C bond of the diacid (75). 

The other two methods used by industry to examine the purity of maleic anhydride are the crystallization point (168) and color deterrnination of the sample (169). These tests determine the temperature at the point of solidification of the molten sample and the initial color properties of the melt. Furthermore, the color test also determines the color of the sample after a two-hour heat treatment at 140°C. The purpose of these tests is to determine the deviation in properties of the sample from those of pure maleic anhydride. This deviation is taken as an indication of the amount of contaminants in the maleic anhydride sample. 

Styrene—maleic anhydride copolymer [9011-13-6] engineering thermoplastics, paper treatment chemicals, floor poHshes, emulsifiers, protective coUoids, antisoil agents, dispersants... 

There are numerous further appHcations for which maleic anhydride serves as a raw material. These appHcations prove the versatiHty of this molecule. The popular artificial sweetener aspartame [22839-47-0] is a dipeptide with one amino acid (l-aspartic acid [56-84-8]) which is produced from maleic anhydride as the starting material. Processes have been reported for production of poly(aspartic acid) [26063-13-8] (184—186) with appHcations for this biodegradable polymer aimed at detergent builders, water treatment, and poly(acryHc acid) [9003-01-4] replacement (184,187,188) (see Detergency). 

Biphenyl [92-52-4] M 154.2, m 70-71 , b 255 , d 0.992. Crystd from EtOH, MeOH, aq MeOH, pet ether (b 40-60 ) or glacial acetic acid. Freed from polar impurities by passage through an alumina column in benzene, followed by evapn. A in CCI4 has been purified by vac distn and by zone refining. Treatment with maleic anhydride removed anthracene-like impurities. Recrystd from EtOH followed by repeated vacuum sublimation and passage through a zone refiner. [Taliani and Breed Phys Chem 88 2351 1984.]... 

Initial materials of this super-tough type were blends of nylon 66 with an ionomer resin (see Chapter 11). More recent materials are understood to be blends of nylon 66 with a modified ethylene-propylene-diene terpolymer rubber (EPDM rubber—also see Chapter 11). One such modification involves treatment of the rubber with maleic anhydride, this reacting by a Diels—Alder or other... 

In the case of 1,3-diphenylisoindole (29), Diels-Alder addition with maleic anhydride is readily reversible, and the position of equilibrium is found to be markedly dependent on the solvent. In ether, for example, the expected adduet (117) is formed in 72% yield, whereas in aeetonitrile solution the adduet is almost completely dissociated to its components. Similarly, the addition product (118) of maleic anhydride and l,3-diphenyl-2-methjdi.soindole is found to be completely dissociated on warming in methanol. The Diels-Alder products (119 and 120) formed by the addition of dimethyl acetylene-dicarboxylate and benzyne respectively to 1,3-diphcnylisoindole, show no tendency to revert to starting materials. An attempt to extrude carbethoxynitrene by thermal and photochemical methods from (121), prepared from the adduct (120) by treatment with butyl-lithium followed by ethyl chloroform ate, was unsuccessful. 

For example, the treatment of cellulose fibers with hot polypropylene-maleic anhydride (MAH-PP) copolymers provides covalent bonds across the interface [40]. The mechanism of reaction can be divided in two steps ... 

As previously discussed, solvents that dissolve cellulose by derivatization may be employed for further functionahzation, e.g., esterification. Thus, cellulose has been dissolved in paraformaldehyde/DMSO and esterified, e.g., by acetic, butyric, and phthalic anhydride, as well as by unsaturated methacrylic and maleic anhydride, in the presence of pyridine, or an acetate catalyst. DS values from 0.2 to 2.0 were obtained, being higher, 2.5 for cellulose acetate. H and NMR spectroscopy have indicated that the hydroxyl group of the methy-lol chains are preferably esterified with the anhydrides. Treatment of celliflose with this solvent system, at 90 °C, with methylene diacetate or ethylene diacetate, in the presence of potassium acetate, led to cellulose acetate with a DS of 1.5. Interestingly, the reaction with acetyl chloride or activated acid is less convenient DMAc or DMF can be substituted for DMSO [215-219]. In another set of experiments, polymer with high o -celliflose content was esterified with trimethylacetic anhydride, 1,2,4-benzenetricarboylic anhydride, trimellitic anhydride, phthalic anhydride, and a pyridine catalyst. The esters were isolated after 8h of reaction at 80-100°C, or Ih at room temperature (trimellitic anhydride). These are versatile compounds with interesting elastomeric and thermoplastic properties, and can be cast as films and membranes [220]. 

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. 

Synthetic Polymers. Synthetic polymers are versatile and offer promise for both targeting and extracellular-intracellular drug delivery. Of the many soluble synthetic polymers known, the poly(amino acids) [poly(L-lysine), poly(L-aspartic acid), and poly(glutamic acid)], poly(hydroxypropylmethacrylamide) copolymers (polyHPMA), and maleic anhydride copolymers have been investigated extensively, particularly in the treatment of cancers. A brief discussion of these materials is presented. 

Itoh and coworkers [223] have shown that fullerene derivatives as 6/2-113, which to date have been prepared in a stepwise procedure, can be obtained in a three-component domino process by treatment of diynes 6/2-109, dimethylphenylsilane 6/2-110 and fullerene (C60) in the presence of a Rh-catalyst [223]. Interestingly, using maleic anhydride as dienophile failed to give the desired cycloadduct, whereas Cso -in spite of its strong tendency to form complexes with various transition metals [224] - never suppressed the catalytic silylative cyclization step to give the diene 6/2-112 (Scheme 6/2.24). 

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