Butane catalytic oxidation

Manufactured by the liquid-phase oxidation of ethanal at 60 C by oxygen or air under pressure in the presence of manganese(ii) ethanoate, the latter preventing the formation of perelhanoic acid. Another important route is the liquid-phase oxidation of butane by air at 50 atm. and 150-250 C in the presence of a metal ethanoate. Some ethanoic acid is produced by the catalytic oxidation of ethanol. Fermentation processes are used only for the production of vinegar. 

Technically, acetaldehyde is mainly made by the oxidation of ethylene using a CuCl2/PdCl2 catalyst system.. Although some acetic acid is still prepared by the catalytic oxidation of acetaldehyde, the main process is the catalytic oxidation of paraffins, usually -butane. 

Commercial production of acetic acid has been revolutionized in the decade 1978—1988. Butane—naphtha Hquid-phase catalytic oxidation has declined precipitously as methanol [67-56-1] or methyl acetate [79-20-9] carbonylation has become the technology of choice in the world market. By-product acetic acid recovery in other hydrocarbon oxidations, eg, in xylene oxidation to terephthaUc acid and propylene conversion to acryflc acid, has also grown. Production from synthesis gas is increasing and the development of alternative raw materials is under serious consideration following widespread dislocations in the cost of raw material (see Chemurgy). 

Liquid-Phase Oxidation. Liquid-phase catalytic oxidation of / -butane is a minor production route for acetic acid manufacture. Formic acid (qv) also is produced commercially by Hquid-phase oxidation of / -butane (18) (see HYDROCARBON OXIDATION). 

Prior to 1975, benzene was catalytically oxidized to produce maleic anhydride, an intermediate in synthesis of polyester resins, lubricant additives, and agricultural chemicals. By 1986 all commercial maleic anhydride was derived from oxidation of / -butane. It is expected that / -butane will remain the feedstock of choice for both economic and environmental reasons. 

On the other hand, the catalytic oxidation of a n-butane, using either cobalt or manganese acetate, produces acetic acid at 75-80% yield. Byproducts of commercial value are obtained in variable amounts. In the Celanese process, the oxidation reaction is performed at a temperature range of 150-225°C and a pressure of approximately 55 atmospheres. ... 

Catalytic oxidation of n-butane at 490° over a cerium chloride, Co-Mo oxide catalyst produces maleic anyhydride ... 

Light naphtha containing hydrocarbons in the C5-C7 range is the preferred feedstock in Europe for producing acetic acid by oxidation. Similar to the catalytic oxidation of n-butane, the oxidation of light naphtha is performed at approximately the same temperature and pressure ranges (170-200°C and =50 atmospheres) in the presence of manganese acetate catalyst. The yield of acetic acid is approximately 40 wt%. 

Two possible interesting acetals are diethoxy ethane or butane. They can be synthesized by the catalyzed reaction of acetaldehyde (obtained by ethanol catalytic oxidation) with two molecules of ethanol, or by the catalyzed reaction of butanal (obtained by catalytic conversion of two molecules of acetaldehyde) with two molecules of ethanol. To achieve a one-pot synthesis, a key aspect for a possible commercial development, it is necessary to develop suitable multifunctional catalysts. Research on these aspects is in progress [63]. 

The third route, catalytic oxidation of butane, producing by-product MEK, accounts for only a modest portion of the total supply, less than 15%. Plants designed to produce acetic acid from the direct oxidation of butane... 

Catalytic Reactions. Catalytic oxidation of butane was carried out in a flow reactor at 713 K after the catalysts were pretreated in an N2 flow at 773 K for 2 h. The feed gas consisted of 1.5% butane, 17% O2, and N2 (balance) (7). The products were analyzed with an on-line gas chromatograph. W/F (W = catalyst weight/g, F = flow rate of butane/ mol-h l) was changed in the range of 1.1 x 10 - 11 x 10 mol g-h by controlling the total flow rate. 

Catalytic Oxidation of Butane. The dependences of the conversion of butane on W/F for (VO)2P207 and Si02/(V0)2P207 are given in Figure 5, where W is the catalyst weight and F is the flow rate of butane. The conversion increased with the increase in W/F. The catalytic activity and the selectivity of oxidation of butane are summarized in Table 2. 

Noncatalytic oxidation to produce acetic acid can be carried out in the gas phase (350-400°C, 5-10 atm) or in the liquid phase (150-200°C). Liquid-phase catalytic oxidations are operated under similar mild conditions. Conditions for the oxidation of naphtha are usually more severe than those for n-butane, and the process gives more complex product mixtures.865-869 Cobalt and other transition-metal salts (Mn, Ni, Cr) are used as catalysts, although cobalt acetate is preferred. In the oxidation carried out in acetic acid solution at almost total conversion, carbon oxides, carboxylic acids and esters, and carbonyl compounds are the major byproducts. Acetic acid is produced in moderate yields (40-60%) and the economy of the process depends largely on the sale of the byproducts (propionic acid, 2-butanone). 

Maleic Anhydride. Gas-phase catalytic oxidation of benzene or n-butane is the principal process for the industrial production of maleic anhydride.973 996-999 Until the 1970s commercial production was based predominantly on benzene. Because of its more favorable economics, a switch to butane as an alternative feedstock has taken place since then.966,999-1002 At present almost all new facilities use n-butane as the starting material. Smaller quantities of maleic anhydride may be recovered as a byproduct of phthalic anhydride manufacture (about 5-6%).1003,1004... 

Maleic anhydride is widely used in polyester resins, agricultural chemicals and lube additives. The growth rate of its production is currently 7-9 percent per year world-wide. In the U.S. the expected consumption by 1983 is 223,000 tons per year ( 5). Conventionally, the production of maleic anhydride via heterogeneous catalytic oxidation of benzene is performed in fixed bed reactors. Rapid increase in benzene prizes and tight benzene-emission control standards caused intense investigations in alternative feedstocks like n-butenes (6), butane ( 5) and the C,-fraction of naphtha crackers (7). As for these alternative feedstocks... 

Raw materials. Maleic acid is a petrochemical prepared by catalytic oxidation of either benzene or, preferably, butane. It is a commodity product (approx 900 000 Te global production) used in many chemical syntheses and polymers. 

In industry many selective oxidations are carried out in a homogeneously catalyzed process. Heterogeneous catalysts are also applied in a number of processes, e.g. total combustion for emission control, oxidative coupling of methane, the synthesis of maleic acid from butanes, the epoxidation of ethylene. Here we focus upon heterogeneous catalysis and of the many examples we have selected one. We will illustrate the characteristics of catalytic oxidation on the basis of the epoxidation of ethylene. It has been chosen because it illustrates well the underlying chemistry in many selective oxidation processes. 

BP Chemicals, Inc. Maleic anhydride n-Butane Fluid-bed catalytic oxidation process with an aqueous-based recovery and purification 3 1994... 

Contractor, R. M. Improved Vapor Phase Catalytic Oxidation of Butane to Maleic Anhydrige, U.S.P., 4,668,802. 

In the first commercial process, introduced in 1933, maleic anhydride was produced by the catalytic oxidation of benzene with air. Although its appeal declined after the 1970s the benzene process is still operated, particularly where -butane is not available. The catalyst is a mixed oxide (70% V2O5 30% M0O3) deposited on a low surface area carrier to limit side reactions. Atom efficiency is inherently low, as implied by the stoichiometry of the oxidation in which two carbon atoms out of six are lost as CO2 (Equation B4). Molar yields however can be relatively high ca. 73%) and are generally higher than those in the -butane processes. 

Oxidation of an n-butane molecule is extensive and involves the transfer of 14 electrons, the cleavage of eight C—H bonds, and the insertion of three oxygen atoms (Figure 1). That this transformation occurs selectively is remarkable in view of other typical selective catalytic oxidation reactions, which involve the transfer of a maximum of only four electrons. 

I 6 Photoelectron Spectroscopy of Catalytic Oxide Materials 63.2.2 Oxidative Dehydrogenation of n-Butane... 

The abundance and low cost of light alkanes have generated in recent years considerable interest in their oxidative catalytic conversion to olefins, oxygenates and nitriles in the petroleum and petrochemical industries [1-4]. Rough estimates place the annual worth of products that have undergone a catalytic oxidation step at 20-40 billion worldwide [4]. Among these, the 14-electron selective oxidation of -butane to maleic anhydride (2,5-furandione) on vanadium-phosphorus-oxide (VPO) catalysts is one of the most fascinating and unique catalytic processes [4,5] ... 

Early higher pressure reaction smdies over Pt-Sn model catalysts by Paffett [62,63] and Somorjai [64, 65] and their coworkers revealed new insights into hydrocarbon catalysis in such systems. Szanyi et al. [62] showed that n-butane hydrogenolysis under moderate pressures (1-200 Torr H3/butane=20) and temperatures (up to 650 K) could be carried out without disruption of the ordered Sn/Pt(lll) surface alloys. This established that such catalytic reactions could be studied while maintaining the composition and geometric structure of these alloys under reducing reaction conditions (but not catalytic oxidation due to the aggressive interaction of O3 with Sn). These ordered Sn/Pt surfaces are qualitatively different from those in many studies of promoters and poisons, or disordered alloys, e.g., Au-Pt, in which the quantitative information on ensemble sizes available for reactions is difficult to determine. 

This paper is an attempt to summarize the situation with respect to the selective catalytic oxidation of light alkanes using heterogeneous catalysts. Methane oxidation reactions and the oxidation of butane to maleic anhydride will only be alluded to occasionally, because they have been reviewed in detail in a large number of papers. 

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