Hydroformylation carbonylation

Table 1.4 Examples of functionalization and defunctionalization with metal NPs in ILs carbonylation, hydroformylation, borylation, hydrosilylation, bond cleavage, hydrogenolysis, aminolysis, and dehalogenation. 

For the phosphine-substituted cobalt carbonyl hydroformylations, it is probable that the mechanism follows the pathway of Heck and Breslow (77, 18), although the possibility of an associative mechanism has been raised (7). The increased stability of the HCo(CO)3PR3 complexes toward loss of CO was cited as being suggestive of a nondissociative pathway. 

The solubility of gases, e.g. H2, CO and O2, is generally good which makes them attractive solvents for catalytic hydrogenations, carbonylations, hydroformylations, and aerobic oxidations. 

The spacer units in 3.60 are assembled from polyphosphazenes that bear p-bromophc-noxy side groups via a lithiation reaction, and treatment with a diorganochlorophosphine to give 3.62. The chemistry is summarized in reaction sequence (45).107 Polymer 3.62 coordinates to a variety of metallo species,108 including osmium cluster compounds and cobalt carbonyl hydroformylation catalysts. When used as a polymeric hydroformylation catalyst, this latter species proved how stable the polyphosphazene backbone is under the drastic conditions often needed for these types of reactions. The weakest bonds in the molecule proved to be those between the phosphine phosphorus atoms and the aromatic spacer groups. 

The solubility of reactive gases such as H2, CO and 02 is also very important in many catalysed reactions such as hydrogenation, carbonylation, hydroformylation and oxidation. The general trend for the solubility of... 

In homogeneous catalysis often a reaction takes place between a gaseous reactant and a liquid reactant in the presence of a catalyst that is dissolved in the liquid phase. Examples are carbonylations, hydroformylations, hydrogenations, hydrocyanation, oxidations, and polymerizations. Typically, reactants such as oxygen, hydrogen, and/or carbon monoxide have to be transferred from the gas phase to the liquid phase, where reaction occurs. The choice of reactor mainly depends on the relative flow rates of gas and liquid, and on the rate of the reaction in comparison to the mass and heat transfer characteristics (see Fig. 8.2). 

Rhone-Poulenc developed ketoprofen [66]. A few synthetic routes have been reported that involving multi-step syntheses [67, 68]. Ketoprofen is produced by similar reaction sequences that were described for naproxen [69]. Transition metal-catalyzed reactions including carbonylations, hydroformylations, and hydrogenations have been applied to the synthesis of ketoprofen. 3-Vinylbenzophenone (4) was obtained from 3-bromo-benzophenone (3) by a Heck reaction. Palladium-catalyzed carbonylation of 4 provided the isopropyl-a-(3-benzoylphenyl)propionate in 95% yield. Ketoprofen was then obtained in 90% yield by hydrolysis of the isopropyl ester [69]. 

DSM, working initially with DuPont and then later with Shell, have developed a process using butadiene and carbon monoxide feedstocks to make caprolactam without ammonium sulfate production in the mid-1990s. Called Altam, the process employs four steps - carbonylation, hydroformylation, reductive amination and cyclization. DSM claims cost reductions of 25-30%, simplified plant operations and lower energy consumption, but the process never reached commercial scale. 

In general, homogeneous catalysts based on HPANs consist of complex equilibrium mixtures of polyanions of different compositions with products of the deg-radative dissociation of the heteropolyanion. All these species can function as the active form or as ligands of a transition metal complex [16]. The HPAN + Pd(II) and HPAN + Rh(I) systems are also used in carbonylation, hydroformylation, and hydrogenation reactions [17]. Other redox systems based on HPANs are also known. Their second component is Tl(III)/Tl(I) [18], Pt(IV)/Pt(II) [19], Ru(IV)/ Ru(II), or Ir(IV)/Ir(III) [20]. 

Carbonylation, hydroformylation (CO-Hj) of olefins catalyzed by metal (Pd or Rh) complexes. 

Metal-catalyzed hydrogenations, carbonylations, hydroformylations, etc. involve transition metals in low oxidation states coordinated to soft ligands, e.g., phosphines, as the catalytically active species and organometallic compounds as reactive... 

Based on the activation and elementary steps outlined, a variety of catalytic reactions can be better understood and catalytic cycles defined. We consider a few major classes of reactions isomerization, hydrogenation, carbonylation, hydroformylation, oxidation, and metathesis. 

For instance substitution chlorination of organic compounds produces hydrogen chloride which must simultaneously desorb back in the gas phase to prevent supersaturation of the liquid phase. Another industrially important process involves "supported liquid phase catalyst", where the reactants have to be transferred from a bulk gas to a liquid reaction phase while the products are released back into the gas phase. Here the catalyst is in the form of a melt on a solid support and it finds applications in alkylation, carbonylation, hydroformylation and oxidation of inorganic and organic compounds. The subject matter was recently reviewed delicately by Villadsen and Liv-berg (11,12). Other examples of these interesting systems are shown in Table 6. 

Cs6k Z, Szalontai G, Czira G, Kollar L. Carbonylation (hydroformylation and hydrocarbalk-oxylation) reactions in the presence of transition metal p-tert-butyl-calix[4]arene-based phosphine and phosphinite systems. J Organomet Chem 1998 570(l) 23-9. 

The reactions of organorhodium compounds or the catalytic reaction of a rhodium complex are insertions, formation reactions of carbene, hydrogenations, hydrometalations, decarbonylations, carbonylations, hydroformylations, cycliza-tions and cyclometalations, etc. 

In comparison to water photolysis [1,2] very little research has been directed at the photoreduction of carbon dioxide and at the photooxidation of carbon monoxide. There are several reasons why chemists should be interested in these two processes. CO2 is a natural and abundant raw material it is a major atmospheric pollutant, involved in the greenhouse effect which may ultimately affect the climate and the temperature of our planet [3]. CO is used in many important industrial processes e.g. carbonylation, hydroformylation, Fisher-Tropsch reactions, and it is one of the major contaminants of industrial gases produced during catalytic processes (e.g., Haber-Bosch synthesis of NH3[4]). There are also fundamental reasons for studying CO2 and CO activation. The former is an inert molecule with carbon in its highest oxidation state and therefore its activation is difficult to achieve. Carbon dioxide could either be reduced to... 

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