Supported catalytic carbonylation reaction

Another successful application of [BMIMJIPFe] ionic liquid supported catalytic microflow reactions for Pd-catalyzed carbonylative Sonogasnira coupling of aryl iodides and phenylacetylene was reported by Rahman et al. (2006). Ionic liquid containing Pd catalysts, CO and the substrates were mixed successively, in different micromixers (channel diameter = 1 and 0.40 mm), and then pumped as a multiphase (ionic liquid-substrate-CO) into heated capillary tube reactor acting as a residence time unit (V=14.1 mL). It was found that Pd-catalyzed production of solely the acetylenic ketones in ionic liquids, when conducted in conjunction with a microreactor, preceded efficiently with superior selectivity and higher yields compared to the conventional batch system, even at low CO pressures. Authors suggested that this improvement in selectivity and yield was the result of a large interfacial... 

Similarly, cyclizative tandem double-carbonylation reactions of 4-pentenyl iodide under irradiation conditions, is boosted by the addition of a catalytic amount of palladium complexes [72]. When performed in the presence of diethylamine, the carbonylation provided a triply carbonylated a,<5-diketo amide as the major product along with the doubly carbonylated y-keto amide (Scheme 6.48). Experimental evidence supports the interplay of two reactive species, radicals and organopalladium... 

The citral conversion and the selectivity to unsaturated alcohols increased with the Ge content, this effect being most obvious on alumina supported catalysts (Fig. 9.8). The selectivity enhancement on alumina in comparison with silica was explained by Ge deposited on the alumina support in the close vicinity of Rh nanoparticles during the catalytic redox reaction. These Ge species would be partially reduced during the reduction step of the catalyst preparation and would promote the activation of the carbonyl group for hydrogenation. Then, the catalytic properties of the bimetallic Rh-Ge/Al203 catalysts prepared by the redox reaction strongly depended on their reduction temperature, which must be... 

Because CO is a poison of many catalytic reactions, supported metal carbonyl clusters are usually treated to remove these ligands. The decarbonylation of supported metal carbonyl clusters sometimes occurs almost without changes in the metal... 

The troublesome process of product separation and catalyst recycling in carbonylation reactions using ionic liquids can be considerably simplified by using a solid ionic phase [68,69] or by introducing of an inert solid support [70]. The continuous liquid-phase carbonylation of methanol has been performed using the rhodium carbonyl iodide complex [Rh(CO)2l2] immobilized on a methylpyridinium cation resin [68,69]. The catalytic activity remains constant for the 2000-h operation with virtually no Rh leaching. IL-impregnated silica was used as a solid support for the Monsanto-type catalyst system [Rh(CO)2l2]-BMM [70]. 

In 2013, Bhanage designed and developed an IL-immobilized palladium catalyst 183 and successfully employed in carbonylation reactions, including alkoxycarbonylation, phenoxycarbonylation, and aminocarbonylation ( heme 24) [67]. Alkoxycarbonylation reaction between aryl iodide 184 and alcohol or phenol or amine was performed in an autoclave pressurized with 0.5 MPa of carbon monoxide. Current process would be useful for the utilization of carbon monoxide for synthesis of valuable chemicals from simple starting materials with the use of recyclable catalyst. Furthermore, this catalytic system avoids use of phosphine ligands. The IL-supported palladium catalyst was recycled up to four successive recycles. 

The silica gel-supported IL-phase catalyst could be applied in the continuous methanol carbonylation [99]. A rhodium carbonyl-functionalized IL was produced inside the silica gel-supported [BMIm]I and used as the catalytically active species for the carbonylation reaction. Scheme 2.24. At 150 °C, the conversion of methanol reached 99% if Mel was used as an additive. The major products were acetic acid (21.4%), methyl acetate (74.4%), and dimethyl ether (4.2%). 

The phenylacetic acid derivative 469 is produced by the carbonylation of the aromatic aldehyde 468 having electron-donating groups[jl26]. The reaction proceeds at 110 C under 50-100 atm of CO with the catalytic system Pd-Ph3P-HCl. The reaction is explained by the successive dicarbonylation of the benzylic chlorides 470 and 471 formed in situ by the addition of HCl to aldehyde to form the malonate 472, followed by decarboxylation. As supporting evidence, mandelic acid is converted into phenylacetic acid under the same reaction conditions[327]. 

Several aluminum- and titanium-based compounds have been supported on silica and alumina [53]. Although silica and alumina themselves catalyze cycloaddition reactions, their catalytic activity is greatly increased when they complex a Lewis acid. Some of these catalysts are among the most active described to date for heterogeneous catalysis of the Diels-Alder reactions of carbonyl-containing dienophiles. The Si02-Et2AlCl catalyst is the most efficient and can be... 

Is the paramagnetic adduct between CO and Cluster A a kinetically intermediate in acetyl-CoA synthesis Questions have been raised about whether this adduct is a catalytic intermediate in the pathway of acetyl-CoA synthesis 187, 188) (as shown in Fig. 13), or is formed in a side reaction that is not on the main catalytic pathway for acetyl-CoA synthesis 189). A variety of biochemical studies have provided strong support for the intermediacy of the [Ni-X-Fe4S4l-CO species as the precursor of the carbonyl group of acetyl-CoA during acetyl-CoA synthesis 133, 183, 185, 190). These studies have included rapid ffeeze-quench EPR, stopped flow, rapid chemical quench, and isotope exchange. 

In the following review we will focus on two classes of systems dispersed metal particles on oxide supports as used for a large variety of catalytic reactions and a model Ziegler-Natta catalyst for low pressure olefin polymerization. The discussion of the first system will focus on the characterization of the environment of deposited metal atoms. To this end, we will discuss the prospects of metal carbonyls, which may be formed during the reaction of metal deposits with a CO gas phase, as probes for mapping the environment of deposited metal atoms [15-19]. 

Metal clusters on supports are typically synthesized from organometallic precursors and often from metal carbonyls, as follows (1) The precursor metal cluster may be deposited onto a support surface from solution or (2) a mononuclear metal complex may react with the support to form an adsorbed metal complex that is treated to convert it into an adsorbed metal carbonyl cluster or (3) a mononuclear metal complex precursor may react with the support in a single reaction to form a metal carbonyl cluster bonded to the support. In a subsequent synthesis step, metal carbonyl clusters on a support may be treated to remove the carbonyl ligands, because these occupy bonding positions that limit the catalytic activity. 

It is worth mentioning that both the carboxylation of epoxides and anilines are acid-base reactions, which do not entail redox processes. Therefore a catalyst active in these reactions must provide acid-base functionality. In this perspective, positively charged gold could be the real player, although a co-catalytic or promotion effect of ze-rovalent gold could also be important. Therefore the catalysts for the oxidative carbonylation of aniline, supported on Merck Ion-exchanger IV, could be actually bifunctional. On one side, Au could catalyze the oxidation of CO with O2 to CO2, a reaction for which it is... 

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