Synthesis reactions maleic anhydride

The oxidation of butane (or butylene or mixtures thereof) to maleic anhydride is a successful example of the replacement of a feedstock (in this case benzene) by a more economical one (Table 1, entry 5). Process conditions are similar to the conventional process starting from aromatics or butylene. Catalysts are based on vanadium and phosphorus oxides [11]. The reaction can be performed in multitubular fixed bed or in fluidized bed reactors. To achieve high selectivity the conversion is limited to <20 % in the fixed bed reactor and the concentration of C4 is limited to values below the explosion limit of approx. 2 mol% in the feed of fixed bed reactors. The fluidized-bed reactor can be operated above the explosion limits but the selectivity is lower than for a fixed bed process. The synthesis of maleic anhydride is also an example of the intensive process development that has occurred in recent decades. In the 1990s DuPont developed and introduced a so called cataloreactant concept on a technical scale. In this process hydrocarbons are oxidized by a catalyst in a high oxidation state and the catalyst is reduced in this first reaction step. In a second reaction step the catalyst is reoxidized separately. DuPont s circulating reactor-regenerator principle thus limits total oxidation of feed and products by the absence of gas phase oxygen in the reaction step of hydrocarbon oxidation [12]. 

In the present paper Werther s two-phase model for fluidized bed reactors is applied to the synthesis of maleic anhydride as an example of a complex reaction system. Based on experimental data found in the literature two process routes differing in the feedstocks used were investigated. In both cases the model is able to describe the behaviour of the fluid bed reactors including the scale-up effects. 

Among the many mathematical models of fluidized bed reactors found in the literature the model of Werther (J ) has the advantage that the scale-dependent influence of the bed hydrodynamics on the reaction behaviour is taken into account. This model has been tested with industrial type gas distributors by means of RTD-measurements (3)and conversion measurements (4), respectively. In the latter investigation (4) a simple heterogeneous catalytic reaction i.e. the catalytic decomposition of ozone has been used. In the present paper the same modelling approach is applied to complex reaction systems. The reaction system chosen as an example of a complex fluid bed reaction is the synthesis of maleic anhydride (Figure 1). 

Several reaction kinetics which differ in the degree of complexity may be found in the literature for the synthesis of maleic anhydride on the basis of benzene (10,11,21). As no major byproducts are reported by C.havarie and coworkers the relatively simple reaction scheme proposed by Ramirez and Calderbank (11) is adopted in the following model calculations ... 

Other catalytic reactions carried out in fluidized-bed reactors are the oxidation of naphthalene to phthalic anhydride [2, 6, 80] the ammoxidation of isobutane to mcthacrylonitrilc [2] the synthesis of maleic anhydride from the naphtha cracker C4 fraction (Mitsubishi process [81, 82]) or from n-butane (ALMA process [83], [84]) the reaction of acetylene with acetic acid to vinyl acetate [2] the oxychlorination of ethylene to 1,2-di-chloroethane [2, 6, 85, 86] the chlorination of methane [2], the reaction of phenol with methanol to cresol and 2,6-xylenol [2, 87] the reaction of methanol to gasoline... 

Another example is the production of maleic anhydride by Mitubishi Chemical Industries, Ltd. in 1970, which is oxidaticm of BB-fraction. Synthesis of maleic anhydride from butylene is a typical consecutive reaction, and it was considered difficult to get high yield by the use of fluid beds. However, it is highly exothermic and application of fluid beds is preferable. 

As cited in Chapter 1, the first example of commercial process using an alkane as feedstock, in substitution of the older process starting from benzene, was the synthesis of maleic anhydride from n-butane. Figure 2.66 briefly recalls the reaction scheme on the model surface of the catalyst (vanadyl pyrophosphate) to evidence the... 

Other less reactive monomers were incorporated into chain ends of oligomers, including divinyl benzene for MMA [138] and maleic anhydride for styrene [139] (Scheme 21) and methacrylates [140]. The method for the synthesis of maleic anhydride terminated PS is based on the fact that maleic anhydride cannot be homopolymerized under normal conditions [141]. These maleic anhydride terminated PSs were used for the compatibilization of the nylon 6-PS binary system in the melt by reaction with NH2-terminated polyamide. 

A Diels-Alder diene synthesis, using maleic anhydride and anthracene, was carried out using DTA by Hartnelin et al. (26). This technique permits the determination of the temperature at which reaction occurs, the melting point of the adduct formed, and the decomposition of the adduct. 

Derivatives of polyisobutylene (6. in Figure 9.1) offer the advantage of control over the molecular weight of the polyisobutylene obtained by cationic polymerization of isobutylene. Condensation on maleic anhydride can be done directly either by thermal activation ( ene-synthesis reaction) (2.1), or by chlorinated polyisobutylene intermediates (2.2). The condensation of the PIBSA on polyethylene polyamines leads to succinimides. Note that one can obtain mono- or disuccinimides. The mono-succinimides are used as... 

The mechanism of the diene synthesis appears to involve an electron transfer from the diene to the dienophile, .e., it is initiated by an ionic reaction. The following scheme may represent the addition of 2 3-dimethylbutadiene to maleic anhydride ... 

Frcc-Radical Reactions. Eree-radical reactions of maleic anhydride are important in polymeri2ations and monomer synthesis. Nucleophilic radicals such as the one from cyclohexane [110-82-7] serve as hydrogen donors that add to maleic anhydride at the double bond to form cyclohexylsuccinic anhydride [5962-96-9] (20) (63). 

A domino reaction,in this case consisting of an inter- and an intramolecular Diels-Alder reaction, is a key step in the synthesis of the hydrocarbon pago-dane 30, reported by Prinzbach et al When the bis-diQnQ 27 is treated with maleic anhydride 4, an initial intermolecular reaction leads to the intermediate product 28, which cannot be isolated, but rather reacts intramolecularly to give the pagodane precursor 29 ... 

Since anhydrides are much more reactive than carboxylic acids, reaction kinetics is controlled by the second step. The scope and apphcations of this reaction are the same as direct polyesterification but are practically limited to the synthesis of unsaturated polyesters and alkyd resins from phtliahc and maleic anhydrides (see Sections 2.4.2.1 and 2.4.23). 

Alkyd resin synthesis. This synthesis consists of two steps. In the first step, a triglyceride oil is reacted at ca. 250°C with polyols, such as glycerol or pentaery-thritol, in tire presence of a basic catalyst to form a monoglyceride. In the second step, phthalic anhydride, with or without another dibasic acid such as maleic anhydride, is added to the reaction medium and reacted at high temperature. The resulting product is a branched polyester (Scheme 2.56). 

Whereas maleic anhydride can react with furan (139a) at ambient pressure, citraconic anhydride (140) reacts only at high pressures due to the strong deactivating effect of the methyl group (Schemes 5.21 and 5.22). The two-step synthesis [53] of the palasonin (141), in an overall yield of 96 %, is a good example of the acceleration of the Diels-Alder by high pressure (Scheme 5.21). Previous synthesis [54] based on the thermal Diels-Alder reaction of furan with methoxy carbonyl maleic anhydride required 12 steps. 

Alkenes can add to double bonds in a reaction different from those discussed in 15-19, which, however, is still formally the addition of RH to a double bond. This is called the ene reaction or the ene synthesis For the reaction to proceed without a catalyst, one of the components must be a reactive dienophile (see 15-58 for a definition of this word) such as maleic anhydride, but the other (which supplies the hydrogen) may be a simple alkene such as propene. Cyclopropene has also been used. ° The reaction is compatible with a variety of functional groups that can be appended to the ene and dienophile. N,N-Diallyl amides give an ene cyclization. 

Although benzobarrelene has been used in a number of recent studies, the best available published synthesis" starts with the Diels-Alder reaction of j8-naphthol and maleic anhydride, affording benzobarrelene in ca. 1% yield after five further steps. Minor improvements allow small quantities of benzobarrelene to be prepared in an overall yield of ca. 10%. The reaction of benzyne with benzene is relatively inefficient, giving benzobarrelene in ca. 2% yield. When benzyne is generated by decomposition of benzenediazonium-2-carboxylate at high dilution in benzene, the yield of benzobarrelene is raised to 14%. The reactions of benzyne with other aromatic substrates are equally inefficient. 

Scheme 4.8 Convergent synthesis plan fortriclosan. Reaction conditions (i) acetyl chloride, AICI3 catalyst (ei = 94.3%) (i) 2CI2 (ef = 81 %) (ii) I/2K2CO3, CuCI catalyst, xylenes (s2 = 48.3%) (iii) 62.5% H2O2, 1/2 maleic anhydride, CH2CI2 ( 3 = 91.3%) (iv) MeOH, 35% HCI catalyst ( 4 = 94.5%). Molecular weights in g/mol are given in parentheses.

The synthesis of Coumarin derivatives can be made cleaner using zeolite H-BEA and even cationic ion-exchange resin like Amberlyst-15 works. Reactions of resorcinol with acrylic/methacrylic acid, maleic anhydride and esters have been studied (Gunnewegh et al., 1996). 

We have previously (13) reported a rapid two step synthesis of 4-(pyrrolidino)pyridine copolymers via the reaction of commercially available maleic anhydride copolymers with 4-aminopyridine followed by reduction with LiAlH, yielding polymers with a high degree of functionalization. 

Figure 7.20 The synthesis of alkenyl succinic anhydride (ASA) via the ene reaction between maleic anhydride and catalytically isomerised alk-l-enes.

A range of reactions of 2-chlorocyclohexyl(dichloro)phosphine (60) with alcohols and epoxides has been described, largely with a view to the synthesis of polymer intermediates and flame-retardants.50 The copolymerization of dichloro(phenyl)-phosphine with styrene and vinyl butyl ether in the presence of maleic anhydride has been studied.61... 

Even more than [6 + 4] and [8 + 2] cycloaddition reactions, the [2 + 2 + 2] cycloaddition reactions require a very well preorganized orientation of the three multiple bonds with respect to each other. In most cases, this kind of cycloaddition reaction is catalyzed by transition metal complexes which preorientate and activate the reacting multiple bonds111,324. The rarity of thermal [2 + 2 + 2] cycloadditions, which are symmetry allowed and usually strongly exothermic, is due to unfavorable entropic factors. High temperatures are required to induce a reaction, as was demonstrated by Berthelot, who described the synthesis of benzene from acetylene in 1866325, and Ullman, who described the reaction between nor-bomadiene and maleic anhydride in 1958326. As a consequence of the limiting scope of this chapter, this section only describes those reactions in which two of the participating multiple bonds are within the same molecule. 

The solids analysis described above can be taken to yet another level by correlating the color measurement to chemical properties. An excellent model system is vanadium pyrophosphate (VPO), which is a well-known catalyst for butane oxidation to maleic anhydride. During the synthesis of the catalyst precursor, solid V2O5 particles are dispersed in a mixture of benzyl alcohol and i-butanol. In this slurry phase, the vanadium is partly reduced. Addition of phosphoric acid leads to a further reduction and the formation of the VPO structure. With a diffuse reflectance (DR) UV-vis probe by Fiberguide Ind., the surface of the suspended solid particles could be monitored during this slurry reaction. Four points can be noted from Figure 4.4 ... 

Anodic oxidation of fiirans in acetic acid leads to the 2,5-diacetoxy-2,5-dihydro-furan 58 [185, 186]which is readily converted to 2-acetoxyfiiran, This has proved a valuable intermediate for the synthesis of butenolides [187]. Reactions in moist acetonitrile yield the 2,5-dihydro-2,5-dihydroxyfurans which can be oxidised to the maleic anhydride 59 [188], Oxidation of furan-2-carboxylic acid in methanol and sulphuric acid is a route to the ester of a-ketoglutaric acid [189]. 

Diels-Alder, imino dienophiles, 65, 2 Diels-Alder, intramolecular, 32, 1 Diels-Alder, maleic anhydride, 4, 1 [4 -h 3], 51, 3 of enones, 44, 2 of ketenes, 45, 2 of nitrones and alkenes, 36, 1 Pauson-Khand, 40, 1 photochemical, 44, 2 retro-Diels-Alder reaction, 52, 1 53, 2 [6-h4], 49, 2 [3-h2], 61, 1 Cyclobutanes, synthesis ... 

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