Ene hydrogenation

In attempts to cany out cyclisation from butadiene 1,3 in the gaseous phase and under photochemical conditions R Srinivasan (J.Amer.Chem.Soc. 88, 3765 (1966) showed that irradiation yields a complex mixture of ethylene, acetylene, but-1 ene, hydrogen and polymers. The quantum yields of acetylene and ethylene formation increase with pressure. 

With palladium—alumina, the products of the reaction of but-l-yne with deuterium [189] were but-l-ene, 99.1% frans-but-2-ene, 0.2% cis-but-2-ene, 0.2% n-butane, 0.5%, until at least 75% of the but-l-yne had reacted. But-l-ene hydrogenation and hydroisomerisation were observed to occur when all the but-l-yne had reacted. The formation of but-2-ene as an initial product was postulated as being the result of a slow isomerisation of but-l-yne to absorbed buta-1 2-diene... 

Figure 3. A comparrison of the hex-l-ene hydrogenation behaviour of the two nanoparticle catalysts Ag4Rul2 and Cu4Rul2. Note how the silver containing catalyst is significantly superior in terms of TOF in the early stages of the reaction (i.e. no induction time).

Similarly, reactions between Ag+ ions and [Ru5C(CO)14]2 have given [Ag3Ruio(C)2( r-Cl)(CO)2g]2 (403), which retains the square pyramidal Ru5C core.581 The Cl atom is presumably derived from the [ppn]Cl or [AsPh4]Cl used to provide counter-cations for this large anion. When anchored inside mesoporous silica (MCM-41), the intact cluster core acts a catalyst for hex-l-ene hydrogenation. 

Tetrahydroquinoxalines (e.g., 24) are also formed by the reaction of N,N -dimethyl-o-phenylenediamine with l,4-dihalogenobut-2-enes. Hydrogenation of compound 24 gives the 2-ethyl derivative. 1,2,3,4-Tetra-... 

The methodology was first reported by Boutonnet et al.. They obtained a supported metal catalyst by depositing ultra-fine particles synthesized in a w/o microemulsion on pumice. The activity of this catalyst was tested in the but-1-ene hydrogenation reaction and compared with the activity of similar catalysts prepared by the traditional impregnation method both from aqueous and alcoholic solutions. The particle size was found to be in the 20-30 A range for the particles prepared from microemulsions and above 200 A for the classical impregnation counterparts. The behaviour of the Pt-based catalyst was found to depend on the preparation method. However, such a correlation between the activity and the preparation method could not be established in the case of Rh and Pd-based catalysts. 

Synonyms Hydrogenated polydec-1-ene Hydrogenated poly-a-olefin... 

For but-l-ene hydrogenation there was no significant isomerisatitni to but-2-ene isomers for the alumina-supported pol3mier, but only for the inqnegnated catalyst (as seen previously [22]). Others have found that the ci trans ratio in isomerisation products accompanying alkene hydrogenation was very variable [23]. 

Kinetics of 1-butyl acrylate hydrogention by catalysts derived from rhodacarboranes [closo-3,3-( PPh<) ) 7-3-H-3,1,2-RhC BqH] and [closo-2,2-(PPho) -2-H-2,l,12-RhC BaHj 1 show slow equilibration in initial hydrido metallation reactions which accounts for the lengthy induction period s. Similar studies of 3-methyl-3-phenyl-but-1- ene hydrogenation and isomerisation are reported . Reductions of nitroarenes, alkenes and benzaldehyde catalysed by trans-[Pd Cl Az9] and trans-[PdCl (AzH) ] AzH=azobenzene) give anilines or hydroxylamines, alkanes and 2-alkenes and benzyl alcohol respectively . 

Atactic poly(methallyl)alcohol reacts with PClPha to give a polyphosphite Pn, and on treatment with [Rh2(Cl)2(CO)4] or [RhaCCOaCnorbornadienela] polymer-bound catalysts are obtained which are active in the hydrogenation of a variety of olefins. The species derived from the norbornadiene complex catalyses oct-l-ene hydrogenation at a rate dependent on catalyst concentration with solutions 0.125 mol 1 in olefin and at a rate oc [olefin] / up to a concentration of 0.3 mol 1. No attempt is made to rationalize these results in mechanistic terms. 

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