Immobilized catalyst, petrochemical

Polymer-Supported Reagents. This field has grown enormously in the last few decades as chemists and engineers have harnessed the obvious merits associated with carrying out a reaction using a readily removable reagent. The concept is essentially an elaboration of the immobilized catalyst field that has been widely applied in industry, especially the petrochemicals industry, for over 50 years. 

An immobilized catalyst concept has been described in a recent patent application (25). The catalyst, used for the dehydrogenation of organic compounds, comprises an organometallic pincer complex bonded to a TUD-1 support. The pincer complex possesses catalytic activity for alkyl group dehydrogenation. This catalyst can be used for various refining and petrochemical processes, such as paraffin dehydrogenation. 

HPAs, however, is their solubility in polar solvents or reactants, such as water or ethanol, which severely limits their application as recyclable solid acid catalysts in the liquid phase. Nonetheless, they exhibit high thermal stability and have been applied in a variety of vapor phase processes for the production of petrochemicals, e.g. olefin hydration and reaction of acetic acid with ethylene [100, 101]. In order to overcome the problem of solubility in polar media, HPAs have been immobilized by occlusion in a silica matrix using the sol-gel technique [101]. For example, silica-occluded H3PW1204o was used as an insoluble solid acid catalyst in several liquid phase reactions such as ester hydrolysis, esterification, hydration and Friedel-Crafts alkylations [101]. HPAs have also been widely applied as catalysts in organic synthesis [102]. 

The field of (alkane) isomerization has been thoroughly exploited by the petrochemical industry, resulting in many publications. The use of immobilized chiral catalysts, however, is still not common nowadays and was only described by Firmenich [85, 86]. They presented the first example of the use of a chiral diphosphino ligand, neither C2-symmetric nor atropic, for the rhodium(I)-cat-alyzed preparation of citronellal 40 via isomerization of allylic amines or alcohols (Scheme 16). The catalyst systems used were polymer-anchored BINAP... 

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