Hydroformylations hydrogenation

With the excephon of methanol and ethanol, most alcohols are produced from olefins, either through hydration [10] or via a hydroformylation-hydrogenation sequence (Scheme 4-1) [11]. 

The existence of two different rhodium species co-existing on the silica support can be used as an advantage by controlling their relative amount. Under standard hydroformylation conditions, the cationic species and the neutral hydride complex are both present in significant amounts. Hence hydroformylation and hydrogenation will both proceed under a CO/H2 atmosphere. Indeed a clean one-pot reaction of 1-octene to 1-nonanol was performed, using the supported catalyst for a hydroformylation-hydrogenation cascade reaction. 98 % of the 1-octene was converted in the... 

TABLE 3.4. Results from switching between hydrogenation, hydroformylation and hydroformylation-hydrogenation sequence reactions using sol-gel immobilised [Rh(2)CO]+ a... 

Table 44 Hydroformylation, hydrogenation, and isomerization turnover rates152...

The rhodium complex with bis(diphenylphosphino)phenoxazine was immobilized on silica using the sol-gel technique or by a direct grafting to commercially available silica [127]. Under standard hydroformylation conditions (CO/H2 atmosphere), a neutral hydridic complex (57) and cationic species (58) (Scheme 4.35) coexist on the support and act as a hydroformylation/hydrogenation sequence catalyst, giving selectively 1-nonanol from 1-octene 98% of 1-octene were converted to mainly linear nonanal which was subsequently hydrogenated to 1-nonanol. The... 

Data in Table III reflect this decreasing ratio of hydroformylation/ hydrogenation rates for this series of olefins. As expected in A — B — C reaction, maximum aldehyde(B) is observed where the initial hydroformylation rate is greatest, i.e., with 1-hexene. Note that the rate constants for 1-hexene relate to the linear aldehyde only. 

Sandee AJ, Reek JNH, Kamer PCJ et al (2001) A silica-supported, switchable, and recyclable hydroformylation-hydrogenation catalyst. J Am Chem Soc 123(35) 8468-8476... 

In the presence of synthesis gas and a noble metal catalyst, other undesired reactions besides hydroformylation are possible and compete with hydroformylation. Hydrogenation and isomerization of the C=C-double bond, as well as... 

Some of the organic reactions performed in ILs are hydroformylation, hydrogenation, isomerization, oligomerization, polymerization, C—C bonding, and acid-catalyzed Friedel-Crafts reactions. 

These results agree with previous studies that show a decrease in olefin isomerization, hydroformylation, hydrogenation, and oligomerization reaction rates with increasing reactant pressure (110,117-120). Our results also provide a simple explanation for the marked increase in product molecular weight that occurs at reactant pressures above atmospheric, a result that sparked the initial interest in Co catalysts for the industrial practice of FT synthesis (1,2). 

These phosphines are typically used as ligands for catalytic reactions such as hydroformylation, hydrogenation, dimerization, and other metal-catalyzed reactions. Other uses for the phosphorus derivatives are Wittig chemistry (vitamin A and E), phase-transfer catalysis, epoxy curing, extractants, and agricultural and pharmaceutical intermediates. 

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). 

Table 1. Formylated Cyclopropanes 7 and Cyclopropanes 8 by Cobalt and Manganese Carbonyl Hydride Mediated Hydroformylation/Hydrogenation of Cyclopropenes ...

SAPC can perform a broad spectrum of reactions such as hydroformylation, hydrogenation and oxidation, for the synthesis of bulk and fine chemicals, pharmaceuticals and their intermediates. Rhodium complexes are the most extensively used, but complexes of ruthenium, platinum, palladium, cobalt, molybdenum and copper have also been employed [63-65]. Owing to interfacial reactions, one of the main advantages of SAPC upon biphasic catalysis is that the solubility of the reactant in the catalytic aqueous-phase does not limit the performance of the supported aqueous phase catalysts. 

It has also been proposed (DavyjGeneral Electric) to cause isobutene to react with allyl alcohol. The allyl r-butyl ether obtained is hydroformylated, hydrogenated and decomposed to butanediol and recyclable isobute ne ... 

USE Catalyst for hydroformylation, hydrogenation, hy-drosilation, isomerization, carboxylation, carbonylation and polymerization reactions. 

Surprisingly, 2,5-dimethoxy-2,5-dihydrofuran did not form the expected aldehydes under CO/H2 pressure (3 MPa) in the presence of the Rh/TPPTS system. Instead of hydroformylation, hydrogenation was the main reaction path in water, where 2,5-dimethoxytetrahydrofuran and its hydrolysis product were obtained. However, hydroformylation occurred when the surface-active phosphine Ph2P(CH2)ioP03Na2 was used [15]. 

The loss of catalyst components with the product stream was determined as 1.2% for rhodium and 2.4% for phosphorus in total over the nine reaction steps. Perhaps even more significant was the demonstration that different reactions could be carried out using the same batch of catalyst without significant cross-contamination. In this case, styrene was subjected to hydroboration, hydroformylation, hydrogenation, and finally hydroboration once more, all using the same rhodium catalyst system (Scheme 2). 

Water-soluble macromolecular metal complexes based on terminally functionalized ethylene oxides and ethylene oxide-propylene oxide block copolymers have been used as catalysts for hydroformylation, hydrogenation, Wacker oxidation of imsaturated compounds, hydroxylation of aromatic compounds, oxidation of saturated and alkylaromatic hydrocarbons, metathesis, Heck reaction, and some asymmetric reactions. 

Modern biobased lubricants are mainly based on rapeseed oil, sunflower oil, soybean oil, and animal fats. These oils easily undergo oxidation due to their content of polyunsaturated fatty acids such as linoleic acid and linolenic acid. Efforts have been made to modify the oils to provide a more stable material and a product more competitive in performance to mineral oil-based lubricants. This modification can involve partial hydrogenation of oil and a shifting of its fatty acids to high oleic acid content [21]. Other reported changes that address the problem of unsaturation include alkylation, acylation, hydroformylation, hydrogenation, oligomerization (polymerization), and epoxidation [20, 22]. 

When a fluid is compressed and heated above the critical conditions (or to supercritical conditions, sc), the differences between gas and liquid disappear. For carbon dioxide, this occurs for temperatures above 31 °C and pressures above 7.3 MPa. For reactions (such as alkylations, aminations, hydroformylations, hydrogenations and Fischer Tropsch synthesis) occurring in supercritical fluids, the reaction rate is often increased dramatically because of improved desorption of heavy molecules minimizing the oxygen and hydrogen solubility limitations, improved heat transfer, and improved selectivity by a catalyst by minimizing pore diffusion limitations. 

ExxonMobil Biphasic carbonylation catalysis using conventional rhodium catalysts in Lewis-acidic ionic liquids, the electrochemical oxidation of sulfur compounds in naphtha, the use of supported ionic liquids, catalytic hydroformylation, hydrogenations, aldol condensations, and even ionic liquid synthesis... 

Heterogenized clusters are used as catalysts for many reactions, for instance, the Fischer-Tropsch synthesis, the water-gas shift reaction, hydroformylation, hydrogenation, polymerization, oligomerization, isomerization, etc. In the case of the Fischer-Tropsch synthesis, catalysts that are prepared from clusters often show considerably higher selectivity than other catalysts. 

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