Catalytic hydrogenation of dienes

This chapter provides a review of the progress in reaction art, reactor techniques and process technology with respect to homogeneous catalytic hydrogenation of diene-based polymers, in accordance with the homogeneous hydrogenation theme of this handbook. 

A number of steroidal dienes have been selectively hydrogenated at the sterically less-hindered position using various catalysts. Raney nickel and PtOa are the most commonly used heterogeneous catalysts for this purpose. Several examples of selectivity in heterogeneous catalytic hydrogenation of dienes are illustrated in Scheme 88. ... 

Butadiene, Using butadiene as the model substrate, it has been found that the catalytic hydrogenation of dienes occurs in three steps (1) reversible addition of hydrido complex to butadiene to form a butenylcobalt complex (Reaction 3) (2) cleavage of the butenylcobalt complex by hydrido complex to form butenes and pentacyanocobaltate(II) (Reaction 4) and (3) hydrogen absorption by pentacyanocobaltate(II) to reform hydrido complex (Reaction 1) 20, 21), The butenylcobalt complex has the same properties as the complex obtained via reaction of y-methyl-allyl bromide with pentacyanocobaltate(II) (21, 22). 

Selective catalytic hydrogenation of dienes and polyenes to monoenes over nickel sulphide supported on alumina or silica finds application in the partial hydrogenation of soybean oil and isoprene in the presence of methylbutenes. A sulphided C0-W/AI2O3 catalyst has been proposed for the selective hydrogenation of dienes in pyrolysis gasoline. 

Liu Y, WuJ, Pan Q, Rempel GL. Green and simple method for catalytic hydrogenation of diene-based polymers. Top Catal. 2012 55 637-643. 

Parks of Stanford University. Of the two samples of cyclopentane photographed, one was prepared for us by Dr. G. W. Whe-land by the catalytic hydrogenation of cyclopenta-diene and the other was provided by Mr. T. A. 

Toshima N, Yonezawa T, Harada M, Asakuara K, Iwasawa Y (1990) The polymer-protected Pd-Pt bimetallic clusters having catalytic activity for selective hydrogenation of diene. Preparation and EXAFS investigation on the structure. Chem Lett 19 815-818... 

Another subject of dispute was the mechanism of the photochemical, chromium carbonyl catalyzed hydrogenation of dienes /42/. The question here was whether the catalytic reaction is started by the dissociation of CO (Equation 42) or by the dissociation of the coordinated diene (Equation 43) /42, 43/. 

Ffirai and Toshima have published several reports on the synthesis of transition-metal nanoparticles by alcoholic reduction of metal salts in the presence of a polymer such as polyvinylalcohol (PVA) or polyvinylpyrrolidone (PVP). This simple and reproducible process can be applied for the preparation of monometallic [32, 33] or bimetallic [34—39] nanoparticles. In this series of articles, the nanoparticles are characterized by different techniques such as transmission electronic microscopy (TEM), UV-visible spectroscopy, electron diffraction (EDX), powder X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) or extended X-ray absorption fine structure (EXAFS, bimetallic systems). The great majority of the particles have a uniform size between 1 and 3 nm. These nanomaterials are efficient catalysts for olefin or diene hydrogenation under mild conditions (30°C, Ph2 = 1 bar)- In the case of bimetallic catalysts, the catalytic activity was seen to depend on their metal composition, and this may also have an influence on the selectivity of the partial hydrogenation of dienes. 

Wiseman and coworkers have succeeded in preparing tricyclo[5.3.0.0 ]decane (393), a CioHig hydrocarbon which unlike adamantane is chiral. Their elegantly simple approach entails Diels-Alder addition of cyclobutene to l,4-dihalocyclohexa-l,3-dienes, catalytic hydrogenation of the adduct, reaction with aluminium triiodide, and ultimately di- -butyltin dihydride reduction. 

Compensation trends are found in the kinetic data reported for the catalytic hydrogenation of several hydrocarbons on bimetallic systems, including the reactions of ethylene on Ni-Cu and on Ni-Au alloys (252), buta-1,3-diene on Ni- Cu alloys (183), benzene on Ni-Cu (but the behavior of benzene on Cu-Pd was less obviously compensatory) (253), and the liquid phase hydrogenation of nitrobenzene on Pd Ag alloys (56). The kinetic characteristics of but-2-yne on Pd-Au alloys (28) was different in that E underwent little variation, while the value of log A systematically diminished as the proportion of palladium in the alloys was reduced. It was concluded that palladium was the active constituent and gold was an inactive diluent. 

Scheme 45 Catalytic hydrogenation of a diene with complex 64d...

Catalytic conversions were experimentally studied in Russia toward the end of the nineteenth century, and especially in the twentieth century, and regularities were empirically established in a number of cases. The work of A. M. Butlerov (1878) on polymerization of olefins with sulfuric acid and boron trifluoride, hydration of acetylene to acetaldehyde over mercury salts by M. G. Kucherov (1881) and a number of catalytic reactions described by V. N. Ipatieff beginning with the turn of the century (139b) are widely known examples. S. V. Lebedev studied hydrogenation of olefins and polymerization of diolefins during the period 1908-13. Soon after World War I he developed a process for the conversion of ethanol to butadiene which is commercially used in Russia. This process has been cited as the first example of commercial application of a double catalyst. Lebedev also developed a method for the polymerization of butadiene to synthetic rubber over sodium as a catalyst. Other Russian chemists (I. A. Kondakov I. Ostromyslenskif) were previously or simultaneously active in rubber synthesis. Lebedev s students are now continuing research on catalytic formation of dienes. 

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