Catalytic vapor-phase

The catalytic vapor-phase oxidation of propylene is generally carried out in a fixed-bed multitube reactor at near atmospheric pressures and elevated temperatures (ca 350°C) molten salt is used for temperature control. Air is commonly used as the oxygen source and steam is added to suppress the formation of flammable gas mixtures. Operation can be single pass or a recycle stream may be employed. Recent interest has focused on improving process efficiency and minimizing process wastes by defining process improvements that use recycle of process gas streams and/or use of new reaction diluents (20-24). 

Acrylonitrile Route. This process, based on the hydrolysis of acrylonitrile (79), is also a propylene route since acrylonitrile (qv) is produced by the catalytic vapor-phase ammoxidation of propylene. 

The first of the benzene polycarboxyUc acids to become a commercial product was phthabc acid, mosdy in the form of the anhydride. The anhydride is obtained by the catalytic vapor-phase air oxidation of o-xylene or naphthalene. The lUPAC name of phthabc anhydride is 1,3-isobenzofurandione... 

Cyanopyridines are usually manufactured from the corresponding picoline by catalytic, vapor-phase ammoxidation (eq. 7) in a fixed- or fluid-bed reactor (28). 3-Cyanopyridine (25) is the most important nitrile, as it undergoes partial or complete hydrolysis under basic conditions to give niacinamide... 

There are two main processes for the synthesis of ethyl alcohol from ethylene. The eadiest to be developed (in 1930 by Union Carbide Corp.) was the indirect hydration process, variously called the strong sulfuric acid—ethylene process, the ethyl sulfate process, the esterification—hydrolysis process, or the sulfation—hydrolysis process. This process is stiU in use in Russia. The other synthesis process, designed to eliminate the use of sulfuric acid and which, since the early 1970s, has completely supplanted the old sulfuric acid process in the United States, is the direct hydration process. This process, the catalytic vapor-phase hydration of ethylene, is now practiced by only three U.S. companies Union Carbide Corp. (UCC), Quantum Chemical Corp., and Eastman Chemical Co. (a Division of Eastman Kodak Co.). UCC imports cmde industrial ethanol, CIE, from SADAF (the joint venture of SABIC and Pecten [Shell]) in Saudi Arabia, and refines it to industrial grade. 

Johnson, P.C., R.C. Lemon and J.M. Berty, Selective Non-Catalytic, Vapor-Phase Oxiation of Saturated Aliphatic Hydrocarbons to Olefin Oxides, 1964, US Patent 3,132,156. 

Isopropyl acetate is produced by the catalytic vapor-phase addition of acetic acid to propylene. A high yield of the ester can be realized (about 99%) ... 

For the manufacturing of sulfosuccinic acid esters, which belong to a special class of surfactants, maleic acid anhydride is needed. Maleic acid anhydride is an important intermediate chemical of the chemical industry. Its worldwide output amounts to about 800,000 tons (1990) [64]. Maleic acid is produced by catalytic vapor phase oxidation process of benzene or n-C4 hydrocarbons in fixed bed or fluidized bed reactors according the following reaction equations. The heat of reaction of the exothermic oxidation processes is very high. 

Oldenberg and Rase (13) have studied the catalytic vapor phase hydrogenation of pro-pionaldehyde over a commercially supported nickel catalyst. Their data indicate that the mathematical form of the reaction rate at very low conversions and 150 °C can be expressed quite well in the following manner. 

Oldenburg and Rase AIChE J., 3 (462), 1957] studied the catalytic vapor phase hydrogenation of propionaldehyde by making low conversion runs on a commercial supported... 

Aniline is an aromatic amine used in the manufacture of dyes, dye intermediates, rubber accelerators, and antioxidants. It has also been used as a solvent, in printing inks, and as an intermediate in the manufacture of pharmaceuticals, photographic developers, plastics, isocyanates, hydroquinones, herbicides, fungicides, and ion-exchange resins. It is produced commercially by catalytic vapor phase hydrogenation of nitrobenzene (Benya and Cornish 1994 HSDB 1996). Production of aniline oil was listed at approximately 1 billion pounds in 1993 (U.S. ITC 1994). Chemical and physical properties are listed in Table 1-2. 

Xyloflning [Xylol refining] A process for isomerizing a petrochemical feedstock containing ethylbenzene and xylenes. The xylenes are mostly converted to the equilibrium mixture of xylenes the ethylbenzene is dealkylated to benzene and ethylene. This is a catalytic, vapor-phase process, operated at approximately 360°C. The catalyst (Encilite-1) is a ZSM-5-type zeolite in which some of the aluminum has been replaced by iron. The catalyst was developed in India in 1981, jointly by the National Chemical Laboratory and Associated Cement Companies. The process was piloted by Indian Petrochemicals Corporation in 1985 and commercialized by that company at Baroda in 1991. 

Styrene is produced by the catalytic vapor phase dehydrogenation of ethylbenzene. Ethylbenzene is made by the Friedel-Crafts condensation of ethylene and benzene. Styrene is also produced by the palladium acetate-catalyzed condensation of ethylene and benzene and by the dehydration of methylphenylcarbinol obtained by the propylation of ethylbenzene. Because of the toxicity of styrene, its concentration in the atmosphere must be severely limited. 

Phthalic Anhydride. Phthalic anhydride is manufactured by the catalytic vapor-phase oxidation of o-xylene [Eq. (9.182)] or naphthalene [Eq. (9.183)] ... 

Reduction. Benzene can be reduced to cyclohexane [110-82-7], C5H12, or cycloolefins. At room temperature and ordinary pressure, benzene, either alone or in hydrocarbon solvents, is quantitatively reduced to cyclohexane with hydrogen and nickel or cobalt (14) catalysts. Catalytic vapor-phase hydrogenation of benzene is readily accomplished at about 200°C with nickel catalysts. Nickel or platinum catalysts are deactivated by the presence of sulfur-containing impurities in the benzene and these metals should only be used with thiophene-free benzene. Catalysts less active and less sensitive to sulfur, such as molybdenum oxide or sulfide, can be used when benzene is contaminated with sulfur-containing impurities. Benzene is reduced to 1,4-cydohexadiene [628-41-1], C6HS, with alkali metals in liquid ammonia solution in the presence of alcohols (15). 

Isobutyronitrile has been prepared by a number of catalytic vapor-phase reactions at elevated temperatures isobutylamine over copper 2 or nickel,3 isobutyramide over alumina,4 a mixture of ammonia and isobutyraldehyde over thorium dioxide,5 and a mixture of ammonia and isobutyl alcohol over copper. Isobutyronitrile also has been obtained by decarboxylation of 2-methyl-2-cyanopropanoic add 7 and from the reaction of iso-butyric acid with potassium thiocyanate.8 The above procedure is a modification of the method used by Walter and McElvain.9... 

Formaldehyde. Formaldehyde may be made from methanol either by catalytic vapor-phase oxidation ... 

Controlled catalytic vapor-phase oxidation converts, for example, 2-, 3-, and 4-picolines into 2-, 3-, and 4-pyridine carboxaldehydes. 

This is a fixed-bed catalytic vapor phase reaction with the reaction heat used to generate high-pressure steam (18+ barg). Using oxygen rather than air reduces vent gas quantity by 95%, and it also reduces energy and capital cost requirements. The oxy EDC is washed (10) and dried (11) before purification in the direct chlorination unit. 

Badarinarayana, M.C., Ibrahim, S.M., Kuloor, N.R., "Single Step Catalytic Vapor Phase Oxidation of Benzene", Ind. J. 

Hammar, C.G.B., "Reaction Kinetics of the Catalytic Vapor-Phase... 

Holsen, J.N., "An Investigation of the Catalytic Vapor Phase Oxidation of Benzene", Ph.D. thesis, Washington University,... 

Catalytic vapor-phase ammoxidation on mixed oxides is an important class of industrial processes. Propene ammoxidation to acrylonitrile is a well established process for the synthesis of this widely used monomer and intermediate. Over the 40 years since its commercial introduction, the yield to acrylonitrile has nearly doubled to over 80% with the fourth generation of catalysts. This is due to the intensive research effort and understanding of the several factors underpinning catalytic activity. Commercial catalysts contain over 20 elements, the presence of all of which is necessary to optimize the catalytic behavior. 

In aromatic heterocycles, chlorine is replaced by hydrogen in catalytic vapor phase hydrogenation over palladium on charcoal at 280 °C. 3,5-Dichlorotrifluoropyridine affords 2,4,6-trifluoropyridine in 75% yield. ... 

J.M. Berty, S. Lee, K. Sivegnanam, and F, Szeifert, Diffusional kinetics of catalytic vapor-phase reversible reactions with decreasing total number of moles, Inst. Chem. Eng., Sympos. Ser. 87 455 (1984). 

In contrast to acetaldehyde, where a choice exists between several well-established manufacturing processes, vinyl acetate has been produced until recently by two principal methods—i.e., by the catalytic vapor-phase acylation of acetylene and by the acetalization of acetaldehyde. The new procedure for vinyl acetate manufacture consists of oxidizing ethylene in acetic acid—a process closely related to the Wacker acetaldehyde process. All three manufacturing approaches are outlined in Table XII. 

Historically, phenol was produced by the distillation of coal tar. Today, phenol is prepared by one of several synthetic methods, such as the fusion of sodium benzenesulfonate with sodium hydroxide followed by acidification the hydrolysis of chlorobenzene by dilute sodium hydroxide at high temperature and pressure to give sodium phenate, which on acidification liberates phenol (Dow process) or the catalytic vapor-phase reaction of steam and chlorobenzene at 500°C (Raschig process). 

With a yield in the order of 75 percent, maleic acid can be made from furfural by a catalytic vapor phase oxidation with air at 270 °C [107]. The overall reaction is... 

Derivation By (1) catalytic vapor-phase reduction of nitrobenzene with hydrogen (2) reduction of nitrobenzene with iron filings using hydrochloric acid as catalyst (3) catalytic reaction of chlorobenzene and aqueous ammonia (4) ammonolysis of phenol (Japan). 

Derivation (1) Reaction of adipic acid and ammonia (catalytic vapor phase) to yield adiponitrile, followed by liquid-phase catalytic hydrogenation. (2) Chlorination of butadiene followed by reaction with sodium cyanide (cuprous chloride catalyst) to 1,4-dicyanobutylene and hydrogenation. 

Chlorofluoroearbons function as chemical intermediates, provided they are consumed rather than released into the atmosphere. CFC-113 serves as the starting material for the production of CTFE monomer. Despite the many years of research into a catalytic vapor-phase process for this conversion, the preferred current method still involves zinc dechlorination in methanol [reaction... 

Exercise 3.7.7. Calculate the maximum conversion of ethylene to alcohol by catalytic vapor-phase hydration at 300°C and 30 atm using an initial steam-ethylene mole ratio of 10. Assume the vapors behave as ideal gases. The following thermodynamic data are available ... 

Catalytic Vapor-Phase Oxidation of Some Four-Carbon Hydrocarbons. 

The difficulties attending the catalytic vapor phase hydration of olefins, while not apparent from the claims made in the patents which have been obtained for such processes, are serious and numerous. Aside from those already mentioned, the difficulties of separating the alcohol from the dilute liquid condensate by distillation and of purifying the alcohols from hydrocarbon polymers by a process of chlorination or selective absorption must be overcome. In view of the success that has attended the hydration of olefins, particularly those higher than ethylene, by means of absorption in sulfuric acid followed by dilution and distillation, it is probable that direct hydration processes at the present stage of the art will be unable to compete as long as cheap sulfuric acid is available. 

Recently Senseman and Stubbs188 have studied the catalytic, vapor phase oxidation of p-cyniene. Previous work on the liquid phase oxidation of this substance had shown it to be readily acted upon by potassium permanganate, nitric acid, or chromic acid. The catalytic vapor phase oxidation led to the formation of water, carbon dioxide, formaldehyde, formic acid, p-toluic acid, and terephthalic acid. The product obtained in greatest yield was p-toluic acid, showing that the primary point of attack of the oxygen was the isopropyl substituent. Thus ... 

---