Maleic anhydride agent

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

Alkenylsuccinic anhydrides made from several linear alpha olefins are used in paper sizing, detergents, and other uses. Sulfosuccinic acid esters serve as surface active agents. Alkyd resins (qv) are used as surface coatings. Chlorendric anhydride [115-27-5] is used as a flame resistant component (see Flame retardants). Tetrahydrophthalic acid [88-98-2] and hexahydrophthalic anhydride [85-42-7] have specialty resin appHcations. Gas barrier films made by grafting maleic anhydride to polypropylene [25085-53-4] film are used in food packaging (qv). Poly(maleic anhydride) [24937-72-2] is used as a scale preventer and corrosion inhibitor (see Corrosion and corrosion control). Maleic anhydride forms copolymers with ethylene glycol methyl vinyl ethers which are partially esterified for biomedical and pharmaceutical uses (189) (see Pharmaceuticals). 

Oxidation. Benzene can be oxidized to a number of different products. Strong oxidizing agents such as permanganate or dichromate oxidize benzene to carbon dioxide and water under rigorous conditions. Benzene can be selectively oxidized in the vapor phase to maleic anhydride. The reaction occurs in the presence of air with a promoted vanadium pentoxide catalyst (11). Prior to 1986, this process provided most of the world s maleic anhydride [108-31 -6] C4H2O2. Currendy maleic anhydride is manufactured from the air oxidation of / -butane also employing a vanadium pentoxide catalyst. 

The original compound, maleimide (2,5-dioxo-A -pyrroline), is synthesized by the cyclo-condensation of ammonia and maleic acid. Similarly, primary amine is added to maleic anhydride, followed by cyclocondensation, to form N-substituted maleimide (Fig. 2). This reaction is applied to the preparation of bis-maleimides (BMl) [1]. At first, BMI was used as a crosslinking agent for natural rubber (NR). An o-dichlorobenzene solution of NR was crosslinked by BMI at I08-150°C in the presence of peroxides. The radicals generated from peroxides react with the double bonds of both BMI and NR [ 1 ]. 

Epoxldation of (12) with a nucleophilic agent occurred only from the outside of the molecule and the necessary oxidation to (7) could be carried out with RuC and NalO. The remaining steps required new reactions based on selenium chemistry and gave methylenomycin in 12% overall yield from maleic anhydride. 

In order to extend the scope of the reaction, and with the aim of designing a greener approach to the above set of reactions, we preformed the acylation of the same substrates with different acylation agents, such as maleic anhydride, p-methoxybenzoic acid and acetic acid (Scheme 48.4). Table 48.3 shows the results for acylation of benzenesulfonamide. 

The crosslinking of ethylene-propylene copolymer rubber (EPR) in the presence of organic peroxides has been investigated by Natta and/or his coworkers (1-3) and others (4,5). Co-agents such as sulfur (3,4) and unsaturated monomers (6), including maleic anhydride (MAH)(3,7) have been utilized in an effort to increase the crosslinking efficiency in the EPR-peroxide system. 

Stabilizing agents are used to maintain drilling fluid rheological properties at highly elevated downhole temperatures. Chromium and chromium-free lignosulfonates, polyglycol ethers, sodium polystyrene sulfonate-co-maleic anhydride), and a melanin polymer have been used in this application. Additives such as sodium diethyldi-thiocarbamate have been used to stabilize aqueous polysaccharides such as xanthan gum (18). 

The most effective agents for diphosphate formation were NHj)HCOO, H2O2 and SCN-. The formation of the cyclic triphosphate was favoured by maleic anhydride or pantoyl lactone, with Ca2+ being added in both cases. 

The mash from the Streptomyces aureofaciens fermentation broth is acidified and filtered. The filtrate is adjusted to the desired pH, usually 7-8.5, and various flocculating or chelating agents may be added (e.g., vinyl acetate-maleic anhydride copolymer, sodium EDTA, ammonium oxalate, Arquad). The precipitate is (1) stirred with filter aid, filtered, stirred with HC1, refiltered, mixed with 2-ethoxyethanol, filtered, washed, and the filtrates are combined, acidified with HC1, NaCl is added, and the crystals are collected, washed with 2-ethoxyethanol, water, and ethanol, and dried (67), or (2) extracted into methyl isobutyl ketone, the extracts are combined, filtered, and acidified with HC1, and the crystals are collected and washed with water, 2-ethoxyethanol, and isopropanol, and vacuum-dried. If the crystals are greenish, they are treated with sodium hydrosulfite at pH 1.8, filtered, washed, and dried as in (1) above (68). 

Figure 7.15 Improvement of the efficiency of rosin as a sizing agent by Diels-Alder reaction with maleic anhydride.

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