For hydroformylation

The 0x0 process is employed to produce higher alcohols from linear and branched higher olefins. Using a catalyst that is highly selective for hydroformylation of linear olefins at the terminal carbon atom. Shell converts olefins from the Shell higher olefin process (SHOP) to alcohols. This results in a product that is up to 75—85% linear when a linear feedstock is employed. Other 0x0 processes, such as those employed by ICI, Exxon, and BASE (all in Europe), produce oxo-alcohols from a-olefin feedstocks such alcohols have a linearity of about 60%. Enichem, on the other hand, produces... 

Butylene isomers also can be expected to show significant differences in reaction rates for metaHation reactions such as hydroboration and hydroformylation (addition of HCo(CO). For example, the rate of addition of di(j -isoamyl)borane to cis-2-huX.en.e is about six times that for addition to trans-2-huX.en.e (15). For hydroformylation of typical 1-olefins, 2-olefins, and 2-methyl-l-olefins, specific rate constants are in the ratio 100 31 1, respectively. 

A new homogeneous process for hydroformylation of olefins using a water-soluble catalyst has been developed (40). The catalyst is based on a rhodium complex and utilizes a water-soluble phosphine such as tri(M-sulfophenyl)phosphine. The use of an aqueous phase simplifies the separation of the catalyst and products (see Oxo process). 

Sodium pyrazolate and 3,5-dimethylpyrazolate, [( " -cod)Rh(/A-Cl)]2, carbon monoxide, 3-(diphenylphosphino)benzoic acid, or (2-formylphenyl)diphenyl-phosphine give rise to complexes 120 (R = H, Me) and 121 (R = H, Me) [94JOM(469)213]. However, 2-(diphenylphosphino)benzoic acid (the carboxyl group in the ortho position) leads to formation of the mononuclear complexes 122. The products appear to be catalysts for hydroformylation reactions [93MI2]. 

The carbonyl [CpFe(CO)2]2 has been successfully employed as a catalyst for hydroformylation of propylene (229) and for the reaction in Eq. (55) (221). Insertion of CO into Fe—C bonds is thought to occur therein. 

Ziegler-Natta catalyst for polymerization of alkenes. Considerable attention has been directed to double-bonded Fischer carbenes of Cr and W, the Schrock carbenes of Ta and Ti, and cyclic polyene ligands of Fe, Co, Cr, and U. Carbonyls of transition metals from groups 6 to 10 of the periodic table include both the monomeric compounds such as Cr(CO)g, Fe(CO)5, Ni(CO)4 and those with two metal groups such as Mn2(CO)io and Co2(CO)s, which is used industrially for hydroformylation. Although their source has not been identified, it has been shown that volatile compounds from landfills contain carbonyls of Mo and W (Feldmann and Cullen 1997). 

Thermomorphic solvent mixtures have been tested for hydroformylation of 1-octene and 1-dodecene to determine the ease of product recovery and catalyst recycling. Using both batch and continuous reactors, we demonstrated the efficacy of a biphasic, thermomorphic, system that had the following advantages ... 

Batch Experiments with Thermomorphic Systems. As a reference, we tested the hydroformylation of 1-octene in a completely homogeneous system using the same rhodium triphenylphosphine catalyst that is used for hydroformylation of lower aldehydes. This is sample R39 in Table 28.1, and gives us a baseline to compare the performance of our systems in terms of conversion and selectivity. To maintain consistency, we performed all the reactions at 100°C using the same amounts of reactants, catalysts and solvents. Under these conditions we only detected aldehyde products no alcohol or alkene isomers were formed. 

Since it is well known that the higher the olefin, the more difficult it is to hydroformylate, we tried our approach on 1-dodecene. We found that when we used 50 50 ethanol/water (R24) and CTAB only (R33) systems they showed no activity for hydroformylation of 1-dodecene whereas, the addition of surfactant to the 50 50 ethanol/water mixture (R27) dramatically increased the reaction rate, as well as the selectivity. 

The catalysts used in hydroformylation are typically organometallic complexes. Cobalt-based catalysts dominated hydroformylation until 1970s thereafter rhodium-based catalysts were commerciahzed. Synthesized aldehydes are typical intermediates for chemical industry [5]. A typical hydroformylation catalyst is modified with a ligand, e.g., tiiphenylphoshine. In recent years, a lot of effort has been put on the ligand chemistry in order to find new ligands for tailored processes [7-9]. In the present study, phosphine-based rhodium catalysts were used for hydroformylation of 1-butene. Despite intensive research on hydroformylation in the last 50 years, both the reaction mechanisms and kinetics are not in the most cases clear. Both associative and dissociative mechanisms have been proposed [5-6]. The discrepancies in mechanistic speculations have also led to a variety of rate equations for hydroformylation processes. 

Recently, a new class of phosphabarrelene/rhodium catalysts has been developed, which for the first time allows for hydroformylation of internal alkenes with very high activity and which proceeds essentially free of alkene isomerization [36-38]. Two examples, results of hydroformylation of an acyclic and a cyclic internal alkene substrate, are depicted in Scheme 2. 

Cobalt carbonyls are the oldest catalysts for hydroformylation and they have been used in industry for many years. They are used either as unmodified carbonyls, or modified with alkylphosphines (Shell process). For propene hydroformylation, they have been replaced by rhodium (Union Carbide, Mitsubishi, Ruhrchemie-Rhone Poulenc). For higher alkenes, cobalt is still the catalyst of choice. Internal alkenes can be used as the substrate as cobalt has a propensity for causing isomerization under a pressure of CO and high preference for the formation of linear aldehydes. Recently a new process was introduced for the hydroformylation of ethene oxide using a cobalt catalyst modified with a diphosphine. In the following we will focus on relevant complexes that have been identified and recently reported reactions of interest. 

The best known rhodium catalyst precursor for hydroformylation is undoubtedly RhH(PPh3)3CO, first reported by Vaska in 1963,167 but its activity for hydroformylation was discovered by Wilkinson and co-workers a few years later.168-171 The chemistry reported in the late 1960s and early 1970s is still... 

Aldehyde dimers and trimers are common byproducts produced during the hydro formylation of propene. Union Carbide addressed the problem in a creative way when it was discovered that the dimers and trimers could be used as the principal reaction solvent for hydroformylation.[32] Elimination of an extraneous solvent simplified the process. The Ester-diol Trimers may equilibrate, as shown in Equation 2.9 to give a mixture of diol, a dimer, and the diester of the diol, which is a tetramer of butanal. 

A variety of techniques have been disclosed for both extending catalyst solution life and for catalyst activity recovery. For hydroformylation, the catalyst consists of rhodium and an organophosphorus ligand. In some circumstances, the value of the or-ganophosphorus ligand in the catalyst solution may approach the value of the rhodium. 

Such compounds may be contacted with partially deactivated hydroformylation catalyst under non-hydroformylation conditions to effect disruption of the phosphido bridges of a rhodium cluster (Equation 2.12). After the treatment period, the catalyst solution is again suitable for hydroformylation. 

Figure 3.12. Silica grafted catalysts for hydroformylation and hydrogenation, the immobilisation is based on hydrogen bonding between the surface and the sulfonate group (supported hydrogen-bonded (SHB)...

TABLE 3.8. Process and reactor specifications for hydroformylation of 1-octene... 

Figure 8.6. Process flow sheet for hydroformylation of 1-octene to 1-nonanal using the CESS approach...

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