Maleic production figures

A number of special purpose resins are available which employ somewhat unusual acids and diluents. A resin of improved heat resistance is obtained by using Nadic anhydride, the Diels-Alder reaction product of cyclopentadiene and maleic anhydride Figure 25.5). 

Concerning the molecular products of butenedial photolysis (Figure 3), the yield of 2(5H)-furanone is well predicted by the simulation, glyoxal and maleic anhydride are overpredicted while the CO yield in the simulation is much lower than observed experimentally. In MCMv3.1 glyoxal and CO are formed as co-products (Figure 4), but this is not consistent with the different yields of these products observed experimentally. Thuener et al. (2003) include a different source of CO in their proposed mechanism, i.e. direct formation fi om photolysis with a yield of 20%. A possible co-product for direct CO production is acrolein formed by an H-shift and C-C cleavage. The acrolein concentration was below the detection limit of the measurement technique, and its maximum yield was estimated to be 10%. No other direct photolysis products were observed and it was not possible to positively determine the mechanism and co-products for CO formation. 

The process requires flow meters for the gas phase—air, butane, recycled gas, nitrogen, oxygen, steam—the liquid phase—condensed water, maleic acid—and the solids—catalyst recirculation from one reactor to the other. In total, there are 248 flow meters and, as shown in Table 6.6, most of these flow meters are dedicated to nitrogen and water. Only four flow meters monitor the product of interest—maleic acid. Figure 6.13 shows some of the major flow... 

Table 5.10 summarizes production figures for the major maleic anhydride producer countries. The largest capacities are operated by Alusuisse Italia (Italy), Nihon lyoryu Kogyo (Japan), CdF-Chimie (France) and Monsanto (USA). 

The bulk of the effluent is run through a cooler (heat exchanger) and a condenser to remove the light ends that include traces of carbon monoxide and carbon dioxide and by-product water. The bottom stream is maleic acid, which is easily dehydrated, as in Figure 20—4, by vacuum distillation or azeotropic distillation with ortho-xylene. See Chapter 3 if youVe forgotten totally everything about azeotropic distillation.) The dehydrated maleic acid is maleic anhydride. Further purification is done by distillation.,... 

The Diels-Alder reaction is a concerted syn addition (meaning the addition is on one side) with the stereochemistry of the dienophile preserved in the stereochemistry of the product. If the dienophile is cis then the product is also cis, and if the dienophile is trans, the product is also trans. See Figure 4-18 for the attack by a cis dienophile. The reaction in Figure 4-18 is the reaction of isoprene with maleic anhydride (c/sj. 

The enzyme acts stereoselectively to produce only the required L-isomer (Figure 4.10). Originally a fermentation process for the production of L-aspartic acid was established. This was modified into an immobilised enzyme process, but since the extracted enzyme is not very stable, an efficient continuous process was not possible. Therefore an immobilised cell system was developed with a very long operational lifetime. Another raw material for L-aspartic acid is maleic anhydride, which is first converted... 

Reaction of butenedial with OH was also shown to give maleic anhydride as a major product (along with glyoxal). Figure 6.15 shows possible mechanisms for... 

Figure 7b shows that the selectivity for dehydrogenation (based on detected products) was very low at low values of on this catalyst, but increased rapidly as the catalyst was reduced. On this catalyst, small amounts of crotonaldehyde and maleic anhydride were also detected. These amounts decreased slowly with increasing . 

The formation of block copolymers from styrene-maleic anhydride and acrylic monomers was also indicated by pyrolytic gas chromatography and infrared spectroscopy. A comparison of the pyrograms of the block copolymers in Figure 7 shows peaks comparable with those obtained when mixtures of the acrylate polymers and poly(styrene-co-maleic anhydride) were pyrolyzed. A characteristic infrared spectrum was observed for the product obtained when macroradicals were added to a solution of methyl methacrylate in benzene. The characteristic bands for methyl methacrylate (MM) are noted on this spectogram in Figure 8. 

Figure 1. Various feedstocks used for the production of maleic anhydride. Right, feedstock and left, product.

Chemistry and general properties. Sulphosuccinates are made in a two-stage synthesis. Firstly an ester is made by reacting maleic anhydride with an alcohol or an ethoxylated alcohol (Figure 4.12). If the molar ratio of alcohol to maleic anhydride is 1 1, the product is called the half-ester, but where 2 mol of alcohol is used per mole of anhydride, the product is a diester. 

Figure 2 Selectivity at 30% conversion for the reactions indicated as a function ofD°H C-H(reactant) - D°HC-h or c-c (product). 1 ethylbenzene to styrene 2. 1-butene to 1, 3-butadiene 3. toluene to benzoic acid 4. acrolein to acrylic acid 5. ethane to enthylene 6. n-butane to maleic anhydride 7. benzene to phenol 8. toluene to benzaldehyde 9. propene to acrolein 10. 1-butene to 2-butanone 11. isobutene to isobutene 12. methanol to formaldehyde 13. methacrolein to methacyclin acid 14. propane to propene 15. ethanol to acetaldehyde 16. isobutene to methacrolein 17. n-butane to butene 18. benzene to maleic anhydride 19. propane to acrolein 20. methane to ethane 21. ethane to acetaldehyde, 22. isobutane to methacrylic acid 23. methane to formaldehyde 24. isobutane to methacrolein.

The structure has been determined by XRD and consists of edge-sharing VO5 units linked by pyrophosphate tetrahedra (Figure 12.2). This is viewed as the active surface for most of the proposed mechanisms. Here we will discuss several of the mechanisms thought to account for the production of maleic anhydride, which have been debated in the literature. 

The oxidation of a branched C4 alkane, isobutane, was carried out to probe the mechanism of the C-H bond activation of alkanes on the VPO catalysts [103]. Maleic anhydride was among the products of oxidation of this branched alkane. In the case of isobutane 29 (Figure 15), the surface-bound peroxo radical would show discrimination in activating first the weaker tertiary C-H bond. The... 

Figure 102. Plant for the Production of Maleic Acid from Furfural.

When the proportion of one type of monomeric unit in a copolymer is small, the detection of the presence in the pyrolysis products of that component is sometimes more difficult. As an example, a sample of poly(ethylene-graft-maleic anhydride), CAS 106343-08-2, with 3% wt. maleic anhydride was pyrolyzed at 600° C in He with separation of a Carbowax column. The results are shown in the upper trace in Figure 6.1.14. 

Figure 5.4. Comparison of energy use among alternatives for the production of maleic anhydride from n-butane. (Source BRIDGES, 2001.)...

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