Dehydrogenation process

Future Developments. The most recent advance in detergent alkylation is the development of a soHd catalyst system. UOP and Compania Espanola de Petroleos SA (CEPSA) have disclosed the joint development of a fixed-bed heterogeneous aromatic alkylation catalyst system for the production of LAB. Petresa, a subsidiary of CEPSA, has announced plans for the constmction of a 75,000 t/yr LAB plant in Quebec, Canada, that will use the UOP / -paraffin dehydrogenation process and the new fixed-bed alkylation process (85). 

Dehydrogenation processes for acetone, methyl isobutyl ketone [108-10-1], and higher ketones (qv) utilizing, in one process, a copper-based catalyst have been disclosed (18,19). Dehydrogenation reaction is used to study the acid—base character of catalytic sites on a series of oxides (20,21). 

Ethyltoluene is manufactured by aluminum chloride-cataly2ed alkylation similar to that used for ethylbenzene production. All three isomers are formed. A typical analysis of the reactor effluent is shown in Table 9. After the unconverted toluene and light by-products are removed, the mixture of ethyltoluene isomers and polyethyltoluenes is fractionated to recover the meta and para isomers (bp 161.3 and 162.0°C, respectively) as the overhead product, which typically contains 0.2% or less ortho isomer (bp 165.1°C). This isomer separation is difficult but essential because (9-ethyltoluene undergoes ring closure to form indan and indene in the subsequent dehydrogenation process. These compounds are even more difficult to remove from vinyltoluene, and their presence in the monomer results in inferior polymers. The o-ethyltoluene and polyethyltoluenes are recovered and recycled to the reactor for isomerization and transalkylation to produce more ethyltoluenes. Fina uses a zeoHte-catalyzed vapor-phase alkylation process to produce ethyltoluenes. 

T. Laegreid, "ADH The Dehydrogenation Process, Status, and PossibiUties," paper presented at SPUNG Seminar, Norway, Sept. 24—25,1991. 

Dehydrogenation processes in particular have been studied, with conversions in most cases well beyond thermodynamic equihbrium Ethane to ethylene, propane to propylene, water-gas shirt reaction CO -I- H9O CO9 + H9, ethylbenzene to styrene, cyclohexane to benzene, and others. Some hydrogenations and oxidations also show improvement in yields in the presence of catalytic membranes, although it is not obvious why the yields should be better since no separation is involved hydrogenation of nitrobenzene to aniline, of cyclopentadiene to cyclopentene, of furfural to furfuryl alcohol, and so on oxidation of ethylene to acetaldehyde, of methanol to formaldehyde, and so on. 

Thermodynamics. Along with stated yields goes heat requirements for the reactor. The thermodynamics for this operation should be checked, as the author once did for a proposed ethyl-benzene dehydrogenation process. Ethylbenzene and steam w-ere fed to the reactor, and unreacted ethyl-benzene and steam exited the reactor together with the sought product, styrene, and eight side products. 

Figure 6-2. The Lummus Crest Catofin dehydrogenation process (1) reactor, (2) compressor, (3) liquid product recovery, (4) product purification.

The use of microbial 1-dehydrogenations is essential to the manufacture of corticosteroids, as chemical dehydrogenation processes are commercially non-competitive. 

Dehydrogenation process utilizing multimetallic catalytic composite Catalyst development catalyst contains Pt and Ge 82... 

Water injection in a dehydrogenation process Improvement of catalyst activity through water injection 84... 

Oxidative dehydrogenation processes Catalyst development Pt group Cu, Sn, and Cl 86... 

If both X and Y are alkyl groups, the reference compound is a singly branched hydrocarbon, and it is converted to a doubly branched structural unit in the hypothetical dehydrogenation process hence... 

In some catalytic processes, it is necessary to avoid carbon-carbon bond cleavage. For example, isobutane is mainly transformed into its lower alkane homologues (hydrogenolysis products) on metal surfaces, while it can be converted more and more selectively into isobutene when the Pt catalysts contain an increasing amount of Sn (selective dehydrogenation process) [131]. 

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