Catalyst within the

Sasol Fischer-Tropsch Process. 1-Propanol is one of the products from Sasol s Fischer-Tropsch process (7). Coal (qv) is gasified ia Lurgi reactors to produce synthesis gas (H2/CO). After separation from gas Hquids and purification, the synthesis gas is fed iato the Sasol Synthol plant where it is entrained with a powdered iron-based catalyst within the fluid-bed reactors. The exothermic Fischer-Tropsch reaction produces a mixture of hydrocarbons (qv) and oxygenates. The condensation products from the process consist of hydrocarbon Hquids and an aqueous stream that contains a mixture of ketones (qv) and alcohols. The ketones and alcohols are recovered and most of the alcohols are used for the blending of high octane gasoline. Some of the alcohol streams are further purified by distillation to yield pure 1-propanol and ethanol ia a multiunit plant, which has a total capacity of 25,000-30,000 t/yr (see Coal conversion processes, gasification). 

Characteristic features of catalysts used are given in Table 1. As emerges from chemisorption data all catalysts within the experimental error have similar mean particle size. This fact has also been proved by TEM for Pt/Si02 and Pt/MCM-41 catalysts. The channel size of MCM-41 was 2.4 nm. 

Initial studies with PHOX indicated a lack of an anion effect, replacement of PFg by SbFg, or BF4 as counter ion had no apparent effect on the overall reaction. However, nearly all reported catalysts within the last decade utilize BArp as a counterion, perhaps for the higher catalyst stability, easier handling, and general reactivity toward a broader range of substrates. 

The first requirement in developing the ACC was to control air-fuel mixtures, and in contemporary cars this is maintained at precisely the 19 1 stoichiometric ratio for aU engine loads, using an exhaust O2 sensor that controls the fuel injection system. The composition and location of the catalyst within the reactor are also crucial to proper design. 

In this case the amount of catalyst within the washcoat is irrelevant (as long as there is enough to make the process mass transfer limited), and the rate is controlled by the rate of... 

We define a membrane reactor as one in which two phases are separated by a wall through which only one species can permeate. It is also common to have catalyst within the... 

FIGURE 2.8 ACE unit coke yield versus conversion (<221°C). Catalysts within the ellipse region produced roughly twice as much coke as the LZM catalyst at the same conversion. (X) New materials—high to moderate acidity, (O) new materials—low acidity, (O) inert, ( ) LZM catalyst, (A) MAB. 

The cure reactions, the viscosity-time-temperature profile, the processing conditions, the resultant epoxy chemical and physical structure, and the mechanical response of a C-fiber/TGDDM-DDS cured epoxy composite are modified by the presence of a BF3-amine complex catalyst within the prepreg. These factors also will be modified... 

Cumene Cracking Activity. Portions of each of the first five separated fractions were regenerated and subjected to cumene cracking investigations in order to determine relative acidity and coke selectivity trends. The catalyst within the... 

The user considers the catalyst within the framework of its function of promoting a chemical reaction, and its properties. 

The valuable advantages of heterogenizing homogeneous catalysts within the zeolite porous structure was then envisioned. 

The key feature of the adequate transition element seems to be in this ability to stabilize both electrophiles and nucleophiles within the same complex. Extra ligands may or may not increase the reactivity of one of these two species and therefore makethe design of a transition metal zeolite based catalyst within the same ease or difficulty as their homogeneous analogues. 

Referring to a mechanistic classification of organocatalysts (Seayad and List 2005), currently the two most prominent classes are Brpnsted acid catalysts and Lewis base catalysts. Within the latter class chiral secondary amines (enamine, iminium, dienamine activation for a short review please refer to List 2006) play an important role and can be considered as—by now—already widely extended mimetics of type I aldolases, whereas acylation catalysts, for example, refer to hydrolases or peptidases (Spivey and McDaid 2007). Thiamine-dependent enzymes, a versatile class of C-C bond forming and destructing biocatalysts (Pohl et al. 2002) with their common catalytically active coenzyme thiamine (vitamin Bi), are understood to be the biomimetic roots ofcar-bene catalysis, a further class of nucleophilic, Lewis base catalysis with increasing importance in the last 5 years. 

Mass transfer kinetics are given by simple linear driving force models. The fraction of catalyst within the whole fixed bed is described by the factor Xcat- Assuming... 

It is generally considered that the major obstacle to the commercialization of reactions employing the fluorous biphasic concept is the cost of the fluorous solvent and the cost of the ligand, which must contain very large amounts of fluorine to retain the catalyst within the fluorous phase. Cost may be reduced by a proper selection... 

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