Propene palladium catalysts

In the presence of copper and palladium catalysts, terminal alkynes 1222 react with trimethylsilyl azide and allyl methyl carbonate to provide 2,4-disubstituted 1,2,3-triazoles 1223 in moderate to good yield. Isomerization of the allyl substituent in the presence of a ruthenium catalyst gives 4-substituted 2-(l-propen-l-yl)-2//-l,2,3-triazoles 1224. 

In Chapter 8 we will discuss the hydroformylation of propene using rhodium catalysts. Rhodium is most suited for the hydroformylation of terminal alkenes, as we shall discuss later. In older plants cobalt is still used for the hydroformylation of propene, but the most economic route for propene hydroformylation is the Ruhrchemie/Rhone-Poulenc process using two-phase catalysis with rhodium catalysts. For higher alkenes, cobalt is still the preferred catalyst, although recently major improvements on rhodium (see Chapter 8) and palladium catalysts have been reported [3],... 

Practical hydroxycarbonylation of olefins is usually carried out with palladium catalysts and requires rather elevated temperatures. Pd/TPPTS [36-39], Pd/TPPMS [40] and Pd/sulfonated XANTHPHOS (51) were all applied for this purpose. In general, TOF-s of several hundred h can be observed under the conditions of Scheme 5.11, and with propene the concentration ratio of linear and branched acids is around l/b=1.3-1.4 [36,38]. At elevated temperatures and at low phosphine/palladium ratios precipitation of palladium black can be observed. It is known, that the highly reactive [Pd(TPPTS)3] forms easily under CO from a Pd(II) catalyst precursor and TPPTS [37], and that in the presence of acids it is in a fast equilibrium with [PdH(TPPTS)3] [39] ... 

Acetoxylation of propene to allyl acetate can be performed in the liquid phase with high selectivity (98%) in acetic acid in the presence of catalytic amounts of palladium trifluoroacetate. The stability and activity of this catalyst can be considerably increased by adding copper (II) trifluoroacetate and sodium acetate as cocatalysts (100 °C, 15 bar, reaction time = 4 h, conversion = 70%, selectivity = 97%). Gas-phase procedures for the manufacture of allyl acetate are described in several patents and use conventional palladium catalysts deposited on alumina or silica, together with cocatalysts (Au, Fe, Bi, etc.) and sodium acetate. The activity and selectivity reported for these catalysts are very high (100-1000 g l-1 h-1, selectivity = 90-95% ).427 A similar procedure has been used for the synthesis of methallyl acetate from 2-methylpropene.428... 

The metal hydride mechanism has been written particularly for hydrocarboxylation reactions with a palladium catalyst.67,68 In the reactions of propene in the presence of (PhaP dCk, the acyl complex (18) was isolated from the reaction mixture, and also shown to be a catalyst for the reaction. 

The reaction of allylic alcohols and aryl halides in the presence of a palladium catalyst has been used in the past to prepare various 0-arylal-dehydes. The procedure described here is essentially that of Heck and Melpolder.3 A similar reaction has been carried out with bromobenzene and 2-methyl-2-propen-l-ol in hexamethylphosphoric triamide (HMPT) as solvent with sodium bicarbonate as base. A variety of other bases have also been used.4 2-Methyl-3-phenylpropanal has been prepared by reacting palladium acetate and phenylmercuric acetate with 2-methyl-2-propen-l-ol.5... 

Alkylation of sodium 1-(alkoxycarbonyl)methyIphosphonates proceeds equally with acetates in THF from low to room temperature or in DME at reflux. The asymmetric allylic alkylation of the sodium diethyl l-(ethoxycarbonyl)methylphosphonate with 3-acetoxy-l,3-diphenyl-l-propene and cyclic allylic acetates in the presence of a chiral palladium catalyst, prepared from chiral phosphine and palladium acetate, in THF at room temperature proceeds in good yields (44-88%) and high ec s. ... 

In a more specialized approach, IL phases have been immobilized in membrane materials. Although the primary driver of this work was the use of these materials as electrochemical devices, they have also been investigated for catalytic applications [20]. Membrane materials composed of air-stable, room-temperature ILs and poly(vinylidene fluoride)-hexafluoropropene copolymers were prepared with the incorporation of the active catalyst species in the form of palladium on activated carbon. Optical imaging revealed that the prepared membranes contained a high dispersion of the palladium catalyst particles. Studies on the materials included evaluating their gas permeability and their catalytic activity for the hydrogenation reaction of propene. 

Co-addition and Co-oligomerisation.—Nickel and palladium catalysts are again much in evidence. The same 7r-tetramethylcyclobutadienenickel dichloride plus alkylaluminium halide mixed catalysts which have been investigated in relation to alkene oligomerisation (see above) catalyse coaddition of ethylene and propene. Kinetic results for this reaction are reported. Product analysis and distribution permit postulation of mechanisms of addition of butadiene and but-2-yne to give 4,5-dimethyl-1-... 

The ignition curves for propene, MEK and toluene total oxidation over gold and palladium catalysts are shown in Figs. 2 (A, B, C). For propene oxidation the observed products are only carbon dioxide and water, indicating complete combustion occttrring during the reaction. However it is found that toluene and MEK oxidations to CO2 are... 

The discovery of palladium trimethylenemethane (TMM) cycloadditions by Trost and Chan over two decades ago constitutes one of the significant advancements in ring-construction methodology [1]. In their seminal work it was shown that in the presence of a palladium(O) catalyst, 2-[(trimethylsilyl)methyl]-2-propen-l-yl acetate (1) generates a TMM-Pd intermediate (2) that serves as the all-carbon 1,3-di-pole. It was further demonstrated that (2) could be efficiently trapped by an electron-deficient olefin to give a methylenecyclopentane via a [3-1-2] cycloaddition (Eq. 1). 

Ionic liquids have already been demonstrated to be effective membrane materials for gas separation when supported within a porous polymer support. However, supported ionic liquid membranes offer another versatile approach by which to perform two-phase catalysis. This technology combines some of the advantages of the ionic liquid as a catalyst solvent with the ruggedness of the ionic liquid-polymer gels. Transition metal complexes based on palladium or rhodium have been incorporated into gas-permeable polymer gels composed of [BMIM][PFg] and poly(vinyli-dene fluoride)-hexafluoropropylene copolymer and have been used to investigate the hydrogenation of propene [21]. 

A synthetically useful example uses 2-[(trimethylsilyl)methyl]-2-propen-1-yl acetate (95), which is commercially available, and a palladium or other transition metal catalyst to generate 96 or 97, which adds to double bonds, to give, in... 

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