Butadiene from Butenes

The production of butadiene from butene involves at least three surface intermediates adsorbed butene, 7t-allyl, and butadiene. One or more of these may be particularly vulnerable to attack by gas-phase oxygen on a-Fe203. From the temperature programmed desorption experiments, it was found that the products of isomerization, selective oxidation, and combustion... 

In 1959, Idol (2), and in 1962, Callahan et al. (2) reported that bismuth/molybdenum catalysts produced acrolein from propylene in higher yields than that obtained in the cuprous oxide system. The authors also found that the bismuth/molybdenum catalysts produced butadiene from butene and, probably more importantly, observed that a mixture of propylene, ammonia, and air yielded acrylonitrile. The bismuth/molybdenum catalysts now more commonly known as bismuth molybdate catalysts were brought to commercial realization by the Standard Oil of Ohio Company (SOHIO), and the vapor-phase oxidation and ammoxidation processes which they developed are now utilized worldwide. 

Cheng, D. A Study on the Fluidized Bed Reactor for Manufacture of Butadiene from Butene (in Chinese), The Proceeding of 5th National Conference on Fluidization, pp. 353-356 (1990). 

Favored at high temperature and low pressure, it is closely related to the manufacture of butadiene from butenes or the primary dehydrogenation observed in the steam cracking of hydrocarbon feedstocks. 

Butadiene from butene Reduced reaction temperature, eliminadon of the butene recovery 4,375 3.09 0.014... 

HX to form an allyl-substituted olefin (e.g. acetoxylation), or it can dimerize to form 1,5-hexadiene. If an olefin containing 3 hydrogens is used, loss of H from the allylic intermediate occurs faster than lattice oxygen insertion, to form a diene with the same number of carbons, e.g. butadiene from butene (oxydehydrogenation). In all of these processes a common allylic intermediate is formed. 

The pattern of commercial production of 1,3-butadiene parallels the overall development of the petrochemical industry. Since its discovery via pyrolysis of various organic materials, butadiene has been manufactured from acetylene as weU as ethanol, both via butanediols (1,3- and 1,4-) as intermediates (see Acetylene-DERIVED chemicals). On a global basis, the importance of these processes has decreased substantially because of the increasing production of butadiene from petroleum sources. China and India stiU convert ethanol to butadiene using the two-step process while Poland and the former USSR use a one-step process (229,230). In the past butadiene also was produced by the dehydrogenation of / -butane and oxydehydrogenation of / -butenes. However, butadiene is now primarily produced as a by-product in the steam cracking of hydrocarbon streams to produce ethylene. Except under market dislocation situations, butadiene is almost exclusively manufactured by this process in the United States, Western Europe, and Japan. 

Polymerization-grade chloroprene is typically at least 99.5% pure, excluding inert solvents that may be present. It must be substantially free of peroxides, polymer [9010-98-4], and inhibitors. A low, controlled concentration of inhibitor is sometimes specified. It must also be free of impurities that are acidic or that will generate additional acidity during emulsion polymerization. Typical impurities are 1-chlorobutadiene [627-22-5] and traces of chlorobutenes (from dehydrochlorination of dichlorobutanes produced from butenes in butadiene [106-99-0]), 3,4-dichlorobutene [760-23-6], and dimers of both chloroprene and butadiene. Gas chromatography is used for analysis of volatile impurities. Dissolved polymer can be detected by turbidity after precipitation with alcohol or determined gravimetrically. Inhibitors and dimers can interfere with quantitative determination of polymer either by precipitation or evaporation if significant amounts are present. 

Acetonitrile serves to greatly enlarge the spread of relative volatilities so that reasonably sized distillation equipment can be used to separate butadiene from the other components in the C4 fraction. The polar ACN acts as a very heavy component and is separated from the product without much difficulty.The feed stream is carefully hydrogenated to reduce the acetylene level rerun, and then fed to the single stage extractive distillation unit. Feed enters near the middle of the extractive distillation tower, while (lean) aqueous ACN is added near but not at the top. Butenes and butanes go overhead as distillate, with some being refluxed to the tower and the rest water washed for removal of entrained ACN. 

The catalysts that allow the production of maleic anhydride from n-butane with high selectivity, like (V0)2P207, are characterized by a strong acidity, that, like a strong basicity, favors the decomposition of alkoxides to give the olefin and the diene. The catalysts that allow the production of maleic anhydride, either from n-butane or from butenes and butadiene, necessarily have particular sites that allow the insertion of oxygen atoms in the 1,4-position of butadiene. These sites are definitely absent on combustion catalysts. 

Extension of the Kunii-Levenspiel bubbling-bed model for first-order reactions to complex systems is of practical significance, since most of the processes conducted in fluidized-bed reactors involve such systems. Thus, the yield or selectivity to a desired product is a primary design issue which should be considered. As described in Chapter 5, reactions may occur in series or parallel, or a combination of both. Specific examples include the production of acrylonitrile from propylene, in which other nitriles may be formed, oxidation of butadiene and butene to produce maleic anhydride and other oxidation products, and the production of phthalic anhydride from naphthalene, in which phthalic anhydride may undergo further oxidation. 

The applications of butene-1 usually require very low levels of isobutylene and butadiene. Sometimes an extra reactor in the MTBE plant is added to get the isobutylene content down from the typical 2.0% to a 0.2% level. Small amounts of butadiene are removed by hydrotreating the stream over a catalyst, which converts the butadiene to butene-2 and maybe some butane. 

Extractive distillation is used to remove butadiene from a C4 stream fractionation can be used to separate out butene-1 adsorption is also sometimes used to separate out butene-1 polymerization is sometimes used to pull out the isobutylene dehydrogenation can be used to convert some of the butylenes and normal butane to butadiene and alkylation is used to convert the butylenes to alkylate. 

Results of a variation of this experiment yield the same conclusion (5). A catalyst is first adsorbed with butadiene, and the unreacted butadiene is desorbed by heating to 210°C. Then a pulse of cis-2-butene is passed over the catalyst at this temperature. The production of butadiene from this pulse is the same as that from an untreated catalyst. Thus, the preadsorbed precursors of combustion products do not affect the selective oxidation reaction. 

Effect of Gaseous Oxygen on the Production of Butadiene from cis -2-Butene... 

We have tested the above hypothesis by investigating the activation of the C-H bonds of /z-butane and iso-butane and the C=C bonds of 1,3-butadiene, 1-butene and iso-butene on clean V(110) and on VC/V(110) surfaces by using HREELS and TDS.5 Figure 24.6 shows the TDS results following the reaction of/j-butane from clean and carbide-modified V(110) surfaces. For each set of TDS experiments, the clean and carbon-modified V(110) surfaces were exposed to identical exposures of /z-butane at 80 K. Desorption peaks from both parent molecules and the decomposition product (hydrogen) are compared. As shown in Figure 24.6, the adsorption of /z-butane on clean V(110) is completely reversible, as indicated by the absence of any H2 desorption peak. On the carbide-modified surfaces, the peak area of molecularly desorbed /z-butane decreases, which is accompanied by an increase in the peak area of H2 at approximately 500 K. Both observations indicate that the fraction of n-butane undergoing decomposition is increased on the carbide-modified surfaces. 

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