1,5,9-Cyclododecatriene selective hydrogenation

A m-RuCl2(CO)2(PPh3)2 complex, which catalyzes hydrogenation of dienes and monoenes, becomes useful in the presence of added phosphine for selective hydrogenation of 1,5,9-cyclododecatriene to cyclododecene the catalyst is a HRuCl(CO)2(PPh3)2 hydride that operates via steps analogous to those of reactions (9)-(11) (144, 145). 

The very unusual selective hydrogenation of ,/3-unsaturated aldehydes to the unsaturated alcohols, Eq. (30), has been accomplished using [RhCl(CO)2]2 in the presence of tertiary amines under oxo conditions (162). RhCl(PPh3)3 systems under similar conditions reduce the olefinic bond (162), as do Co2(CO)8 systems in the presence of amines or phosphites (163). Further details on the versatile Rh(BH4)(amide)py2Cl2 systems (/, p. 280) have appeared (164, 165) ketones are also slowly hydrogenated (166), and 1,5,9-cyclododecatriene has been selectively reduced to cyclododecene (167). 

Use of molten salts as solvent allows easy separation of organic products by distillation (376), and in this way PtCl2 with tetraalkylammonium salts of SnCl3 and GeCl3 has been used to selectively hydrogenate 1,5,9-cyclododecatriene to cyclododecene the salts in this case act as both solvent and ligand (377). A molten salt medium has been used in a homogeneously catalyzed Fischer-Tropsch synthesis (see Section VI,B). 

Fig. 21.6 The effect of tin in the selective hydrogenation of 1,5,9-cyclododecatriene (CDT) using anchored monometallic and bimetallic cluster catalysts. The reaction conditions were CDTsSO g catalysts25 mg H pressure=30 bar, T=373 K, and ts8 h...

CDE, which is of pivotal importance in many industrial processes, is normally prepared by the selective hydrogenation of 1,5,9-cyclododecatriene (CDT), with metallic Pd being the catalyst of choice. Pd suffers from its lack of selectivity, and a considerable quantity of cyclododecane (CDA) appears as a coproduct of the reaction. 

Adams RD, Boswell EM, Captain B, Hungiia AB, Midgley PA, Raja R, Thomas JM (2007) Bimetallic Ru-Sn nanoparticle catalysts for the solvent-free selective hydrogenation of 1, 5, 9-cyclododecatriene to cyclododecene. Angew Chem Int Ed Engl 46 8182... 

Selective hydrogenation of 1,5,9-cyclodndecatriene to cyclododecene. A mixture of tram,trans,lrans-1,5,9-cyclododecatriene (1) and trans,trans,eis-1,5,9-cyclodode-catriene (2) in a 3 2 ratio can be homogeneously hydrogenated to cyclododecene... 

Selective hydrogenation of polyenes to monoenes is possible with homogeneous catalysts. Dichlorodicarbonylbis(triphenylphosphine)ruthenium(II) catalyzed the selective reduction of 1,5,9-cyclododecatriene to cyclododecene, as well as dichloro-tris(triphenylphosphine)ruthenium(II) ... 

Selective hydrogenations. This is a satisfactory catalyst for selective hydrogenation of 1,5,9-cyclododecatriene, 1,5-cyclooctadiene, and several 1,6-dienes to monoenes. 

The selective hydrogenation of mixtures of cyclododecatriene (CDT) isomers, easily available through cyclotrinmizatitm of butadiaie, represents a convenient route to cis- and trans-cyclododecene (CDE). These lattm- conqxMinds are of great practical importance because can be employed to prepare compounds such as 1,12-dodecandioic acid, 1,12-diaminododecane, 12-amminododecanoic acid lactam, which are monomers for polyamide manufacture, and cyclododecanecarboxilic acid, a pesticide, and its esters used as plasticizm. 

The hydrogenation of 1,5,9-cyclododecatriene (1,5,9-CDT) to cyclododecadienes (CDD) and cyclododecene (CDE) proceeds much less selectively than in the case of 1,5-COD. This may be due to the fact that the three double bonds in 1,5,9-CDT cannot assist each other on adsorption to catalyst, as may be deduced from the inspection of its molecular model. Thus, it is expected that the difference in strength of adsorption or reactivity between 1,5,9-CDT and CDD or CDE would be considerably smaller than that between 1,5-COD and COE. Hanika et al. studied the hydrogenation of 1,5,9-... 

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