Oxidative dehydrogenation butadiene production

Production of styrene from butadiene has also been extensively investigated. Recentiy, Dow announced licensing a process involving cyclodimerization of 1,3-butadiene to 4-vinylcyclohexene, followed by oxidative dehydrogenation of the vinylcyclohexene to styrene (65,66). The cyclodimerization step takes place in... 

Butadiene monomer can be produced by a number of different processes. The dominant method of production is as a by-product from the steam cracking of naphtha to produce ethylene. The BD is recovered from the C4 fractions by extractive distillation. Butadiene is generally produced by dehydrogenation or oxidative dehydrogenation of C4 hydrocarbons. " ... 

A somewhat different application of perovskites is the oxidative dehydrogenation of olefins. Kehl et al. (202) reported that Lao.8Cro.65Feo.55Ch can be used for butene dehydrogenation to butadiene and also for the conversion of other monoolefins containing at least four C atoms, such as the production of isoprene from isoamylenes. 

Catalytic (nonoxidative and oxidative) dehydrogenation is an important industrial method of hydrocarbon processing (for example, butene and butadiene production from butane [17a] and transformation of ethylbenzene to styrene [17b-f]), in view of which a great number of papers have been devoted to catalytic dehydrogenation (see, e.g., reviews and monographs [18], recent original publications [19] and patents [20]). 

At present there are a few industrial alkane oxidation processes, for example, the synthesis of maleic anhydride by oxidation of butane [32], and the synthesis of butenes and 1,3-butadiene by oxidative dehydrogenation of butane [33]. The most difficult problem with alkanes is to stop the oxidation at the stage of a necessary product, since oxidation of gaseous hydrocarbon on a solid... 

Batch Di (3-pentyl) Malate Process Acetaldehyde from Acetic Acid Ethylene by Oxidative Dehydrogenation of Ethane Butadiene to n-Butyraldehyde and n-Butanol Methacrylic Acid to Methylmethacrylate Coproduction of Ethylene and Acetic Acid from Ethane Methylmethacrylate from Propyne Mixed-C4 Byproduct Upgrade Hydrogen Peroxide Manufacture Di-tem fljy-butyl-peroxide Manufacture Vinyl Acetate Process PM Acetate Manufacture Propoxylated Ethylenediamine Petroleum Products Fuel Additives for Cleaner Emissions Gas Manufacture... 

By far the largest outlet for benzene (approx. 60%) is styrene (phenyl-ethene), produced by the reaction of benzene with ethylene a variety of liquid and gas phase processes, with mineral or Lewis acid catalysts, are used. The ethylbenzene is then dehydrogenated to styrene at 600-650°C over iron or other metal oxide catalysts in over 90% selectivity. Co-production with propylene oxide (section 12.8.2) also requires ethylbenzene, but a route involving the cyclodimerization of 1,3-butadiene to 4-vinyl-(ethenyl-) cyclohexene, for (oxidative) dehydrogenation to styrene, is being developed by both DSM (in Holland) and Dow. 60-70% of all styrene is used for homopolymers, the remainder for co-polymer resins. Other major uses of benzene are cumene (20%, see phenol), cyclohexane (13%) and nitrobenzene (5%). Major outlets for toluene (over 2 5 Mt per annum) are for solvent use and conversion to dinitrotoluene. 

The best olefin yields were observed over Pt-coated monoliths. In the case of ethane/02 mixtures, selectivities to ethylene up to 65% at 70% ethane conversion and complete O2 conversion were reported." The oxidative dehydrogenation of propane and -butane produced total olefin select vies of about 60% (mixtures of ethylene and propylene) with high paraffin conversions." " Mixtures of ethylene, propylene and 1-butene were observed by the partial oxidation of -pentane and n-hexane ethylene, cyclohexene, butadiene and propylene were the most abundant products of the partial oxidation of cyclohexane." ... 

The oxidative dehydrogenation of n-butane to butane and butadiene is accompanied by side-reactions of deep oxidation of products and reactant to CO and CO2. The reaction network is shown in Figure 9.5. 

Styrene is manufactured by alkylating benzene with ethene followed by dehydrogenation, or from petroleum reformate coproduction with propylene oxide. Styrene is used almost exclusively for the manufacture of polymers, of which the most important are polystyrene, ABS plastics and styrene-butadiene rubber. U.S. production 1980 3 megatonnes. 

When the Diels-Alder reaction between butadiene and itself is carried out in the presence of alkah metal hydroxide or carbonate (such as KOH, Na2C02, and K CO on alumina or magnesia supports) dehydrogenation of the product, vinylcyclohexene, to ethylben2ene can occur at the same time (134). The same reaction can take place on simple metal oxides like Zr02, MgO, CaO, SrO, and BaO (135). 

During World War II, production of butadiene (qv) from ethanol was of great importance. About 60% of the butadiene produced in the United States during that time was obtained by a two-step process utilizing a 3 1 mixture of ethanol and acetaldehyde at atmospheric pressure and a catalyst of tantalum oxide and siHca gel at 325—350°C (393—397). Extensive catalytic studies were reported (398—401) including a fluidized process (402). However, because of later developments in the manufacture of butadiene by the dehydrogenation of butane and butenes, and by naphtha cracking, the use of ethanol as a raw material for this purpose has all but disappeared. 

For the 8.2 V/nm sample, the products observed for the pulse reaction at 400°C consisted of only dehydrogenation products (butenes and butadiene) and carbon oxides. No oxygenates were observed, and the carbon balance for each pulse was satisfied within experimental error. The selectivity for dehydrogenation is shown in Fig. 3a as a function of 0. It shows that the selectivity was very low when the catalyst was in a nearly fully oxidized state, but increased rapidly when the catalyst was reduced beyond 0 = 0.15. It should be noted that the dependence of selectivity for dehydrogenation on 0 shown in the figure was not... 

The oxidation of butane on these orthovanadates were tested at 500°C in a flow reactor using a butane oxygen helium ratio of 4 8 88. The observed products were isomers of butene, butadiene, CO, and CO2. The carbon balance in these experiments were within experimental errors, thus the amount of any undetected product if present should be small. The selectivity for dehydrogenation (butenes and butadiene) was found to depend on the butane conversion and be quite different for different orthovanadates. Fig. 4 shows the selectivity for dehydrogenation at 12.5% conversion of butane [15,18,19]. Its value ranged from a high of over 60% for Mg3(V04)2 to a low of less than 5% for... 

Thus dehydrogenation is the primary reaction in the oxidation of alkane, and most of the degradation products are formed from secondary reactions. This has been demonstrated experimentally (8). For example, butenes and butadiene are formed with high selectivities at low conversions in the oxidation of butane. 

Binary and ternary oxide compounds with a spinel structure have been studied by several authors. Butadiene can be produced with very high selectivities over these compounds. Rennard et al. [263,264] have studied a variety of oxidation reactions over this type of catalyst, particularly MgCrFe04 and ZnCrFe04, and conclude that only the dehydrogenation to a conjugated product is selectively catalyzed. In the absence of such a possibility, only combustion takes place. The latter is also the conclusion of Zanderighi et al. [358] from a study of the propene oxidation over spinels. 

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