Hydrogen technology, catalysts

AlCl and Hydrogen Chloride Catalyst. Historically, AIQ processes have been used more extensively for the production of ethylbenzene than for the production of cumene. In 1976, Monsanto developed an improved cumene process that uses an AIQ. catalyst, and by the mid-1980s, the technology had been successfully commercialized. The overall yields of cumene for this process can be as high as 99 wt % based on benzene and 98 wt % based on propylene (60). 

When the catalyst was recycled for use in the second batch, the deactivation was found to be rather severe. This, however, was expected - mainly due to the very small amount of catalyst applied into the hydrogenation batch. Nevertheless, the results indicated that ultrasound enhanced the reaction rate. The maximal yields were 0.60/0.08 at 220 min, compared with those obtained by conventional hydrogenation technology, 0.42/0.06 at 345 min. It is probable that the yield of OL would eventually revert in the absence of acoustic irradiation, as well. 

Several hydrogenations of olefins and aromatics are performed at relatively low temperature using supported metal catalysts, mostly alumina-supported nickel, cobalt, palladium, or platinum. For example, Pt/Al203 catalysts are applied in various vapor-phase benzene hydrogenation technologies, to produce cyclohexane or to reduce benzene content in gasoline. The benzene hydrogenation reaction is carried out at temperatures of... 

A system for application in a cell phone also based on MEMS technology was designed by Samsung [40] (Figure 23.4). Aspects such as the start-up time for the reaction temperature and the hydrogen flow, catalyst durability and volume of the total system were considered. The catalyst was introduced as small particles (50-100 tm) and a uniform packing was obtained. Maximum power output was 2.4 W, sufficient for a cell phone. 

In urethane technology, catalysts are widely used in foam manufacture where two or more catalysts are required to give the desired balance of reaction rates between compounds of differing active hydrogen activity. 

Bronsted Acids. Sulfuric acid (H2SO4) is an inexpensive, easy to handle protic acid used widely as catalyst in hydrolysis, hydration and dehydration, elimination, substitution, and rearrangements. It also catalyzes aromatic electrophilic substitutions mostly Friedel-Crafts acylations and alkylations (22). A very important application of sulfuric acid is its use in commercial isoalkane-alkene alkylation technologies. These commercial processes are still based on the use of sulfuric acid (and hydrogen fluoride) catalysts (23). 

Razavi A (2004) Synthesis of hydrogenated metallocene catalyst for olefin polymerization and polyolefins prepared thereby. Patent WO 2004/078,798 A2 2004/0,916, Fina Technology... 

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