Catalyst system development

Currently, almost all cumene is produced commercially by two processes ( /) a fixed-bed, kieselguhr-supported phosphoric acid catalyst system developed by UOP and (2) a homogeneous AlCl and hydrogen chloride catalyst system developed by Monsanto. 

The most widely used homogeneous palladium catalyst is palladium carboxylate. Table 6 lists the palladium-based catalyst systems developed for NBR hydrogenation [75-87]. They are regarded as homogeneous cata-... 

The most active palladium catalyst system developed for the asymmetric hydrosilylation of cyclopentadiene (Scheme 23) involves the use of the (/ )-MOP-phen ligand (38), which shows significant enhancement of enantioselectivity compared to (R)-MeO-MOP (80% ee from (38), 39% ee from (36a)).114 Other phosphine ligands that afford active palladium catalysts for the same transformation include the /3-7V-sulfonylaminoalkylphosphine (39) and phosphetane ligand (40) (Equation (13)).115-117 A comparison of the enantioselectivities of these ligands for the palladium-catalyzed hydrosilylation of cyclopentadiene is given in Table 8. 

Most of the terephthalic acid is produced with a catalyst system developed by Scientific Design. It was purchased by Amoco and Mitsui and is referred to as the Amoco Oxidation. The solvent is acetic acid. Compressed air is used as the source for oxygen. The catalyst dissolved in acetic acid and the two reactants are continuously fed into the reactor. The temperature is around 200 °C and the pressure is approximately 25 bar. The reaction is very exothermic (1280 klrnoT1, calculation from data in Stull et al [16] often a much higher, erroneous value is cited). This heat of reaction is removed by evaporation/condensation of acetic acid and can be used in the solvent distillation/purification part of the plant. A scrubber washes the vent gases... 

One important variant of Rh/PPhs catalysis is the two-phase catalyst system developed by Kuntz at Rhone-Poulenc in 1981, using a sulfonated tri-phenylphosphine ligand, P(C6H4-m-S03Na)3 (TPPTS) to generate the water soluble catalyst RhH(C0) P(C6H4-m-S03Na)3]3. 

Whereas the cobalt catalyst systems developed by BASF in particular guarantee a methanol ooce-through conversion of 70 per cent and molar yields in relation to alcohol and carbon monoxide better than 5 and 60 per cent, those developed by Monsanto, based on rhodium, offer better performance. Methanol once-through conversion may exceed 90 per cent and molar yields in relation to alcohol and carbon monoxide are between 98 and 99 per cent and 90 per cent respectively. 

The catalyst system developed at the Koninklijke/Shell Laboratorium in Amsterdam, The Netherlands, for the RIM polymerization of DCPD is WCV 2,6-diisopropylphenol (1/2) with R3SnH as cocatalyst. Both components are soluble in DCPD and have a long shelf-life. This catalyst system has the advantage of being able to polymerize DCPD of technical quality (van Deursen 1989). 

The high-pressure process relied on large and complex plants that required careful process control. Therefore, the discovery in 1953 of the appropriate catalysts that allowed the process to be carried under low pressure ( 500 psi) was welcomed by the industry [7]. Three types of catalysts were developed about that time the Ziegler-type catalysts typically obtained by reacting alkyl aluminum compounds with titanium chloride metal oxide catalyst systems, developed by Phillips Petroleum in the United States, typically made of chromium oxide supported on a silicaceous carrier [8]) and a different type of oxide catalyst developed by Standard Oil Company. The first plants based on the Ziegler catalyst went on line in Germany by 1955 and a plant based on the Phillips catalyst in Texas opened in 1957. The third catalyst system developed much slower and was picked up by the Japanese plastics industry in a plant opened in 1961. 

A base polymer particularly interesting for studying the effect of the aforementioned mechanisms on rubber failure is polybutadiene. In fact, polybutadiene microstructure can be changed in an extremely wide range, by making use of the host of catalyst systems. developed by the ingenuity of chemists, just starting with the same monomer. 

Finally, I would like to thank Dr. Max P. McDaniel of Chevron Phillips Chemical Company in Bartlesville, Oklahoma, for many helpful discussions on the development of the Phillips loop process and catalyst systems developed by Phillips Petroleum Company, and later by Chevron Phillips Chemical Company for the slurry process. 

QUACORR is the trademark for furfuryl alcohol based resin/catalyst systems developed by the Quaker Oats Company for the manufacture of fiberglass reinforced plastic (FRP) equipment. QUACORR laminates exhibit abroad range of solvent and chemical resistance combined with excellent physical, flame spread, and smoke development properties. 

In catalyst systems developed for polypropylene like the single site metallocene catalysts, highly isotactic polypropylene structures with configurational defects are obtained by a chain-end mechanism of stereocontrol. For catalytic polymerizations where the tacticity is high, configurational defects can be recognized. 

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