Hydroformylation, of olefins

The hydroformylation (or 0x0 ) reaction was discovered in 1938 by Roelen who was working on the formation of oxygenates as by-products of the Fischer-Tropsch reaction over cobalt catalysts. It soon became clear that the aldehydes and alcohols found were the products of secondary reactions undergone by the 1-alkenes (which are the primary products of the Fischer-Tropsch reaction, Section 4.7.2) with syngas. Further work showed that Roelen had discovered a new reaction, in which the elements of H and CHO were added to an olefin (hence hydroformylation), and which was catalyzed by cobalt. It was later found that the true precatalyst was not cobalt metal but derivatives of dicobalt octacarbonyl, such as the hydride, CoH(CO)4. 

The process was rapidly commercialized by BASF and has been developed around the world especially to make C4 oxygenates (butyraldehde and butanol) from propylene. The process is very important and many catalyst variations are known. 

The largest volume hydroformylation reaction converts propylene into n-butyraldehyde, from which is made 1-butanol for solvents, or 2-ethylhexanol (the phthalate ester of which has been widely used as a plasticizer for PVC) via an aldol condensation. Estimated world production of butanol is approaching 2 Mt/a. 

Hydroformylation of olefins is a chief industrial process for the manufacture of aldehydes and alcohols by reaction with CO and in presence of a 

A number of catalysts were tried for the hydroformylation of olefins. Main among these are  

Finally a variety of 1-alkenes were hydroformylated with a highly water-soluble tris-sulphonated ligand, P(m-PhS03Na). Some more effective catalysts involving the use of other sulphonated phosphine ligands have also been developed.  

The aqueous biphasic hydroformylation of propene, namely the Ruhrchemie/ Rhone Poulenc (RCH/RP) process, has been widely used to produce n-butanal and many attempts have been proposed to improve this catalytic system, such as a thermoregulated phase transfer (TRPT) Rh(I) complex catalyst [74]. Moreover, Bonnemann et al. [75] have proved the in situ formation of Rh colloids when such a catalyst was applied to the aqueous biphasic hydroformylation of 1-octene. 

Recently, Dupont et al. [76] have reported the hydroformylation of olefins in neat conditions using unmodified or Xantphos-modified Rh(0) nanoparticles, prepared by simple hydrogenation reduction of the chloride salts in imidazolium ionic liquids. They have shown that the particle size has a strong influence on the selectivity of the hydroformylation (Table 11.13). 

When using 5.0 run Rh(0) nanoparticles, the olefins are converted into aldehydes (Table 11.13, entries 1 and 4) and the addition ofXantphos leads to linear/branched selectivities up to 25 (Table 11.13, entry 2). With smaller colloids (2.7nm), the 

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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). 

Olefin Hydroformylation (The Oxo Process). One of the most important iadustrial applications of transition-metal complex catalysis is the hydroformylation of olefins (23), ihusttated for propjdene ... 

Concern for the conservation of energy and materials maintains high interest in catalytic and electrochemistry. Oxygen in the presence of metal catalysts is used in CUPROUS ION-CATALYZED OXIDATIVE CLEAVAGE OF AROMATIC o-DIAMINES BY OXYGEN (E,Z)-2,4-HEXADIENEDINITRILE and OXIDATION WITH BIS(SALI-CYLIDENE)ETHYLENEDIIMINOCOBALT(II) (SALCOMINE) 2,6-DI-important industrial method, is accomplished in a convenient lab-scale process in ALDEHYDES FROM OLEFINS CYCLOHEXANE-CARBOXALDEHYDE. An effective and useful electrochemical synthesis is illustrated in the procedure 3,3,6,6-TETRAMETHOXY-1,4-CYCLOHEX ADIENE. ... 

Cationic phosphine ligands containing guanidiniumphenyl moieties were originally developed in order to make use of their pronounced solubility in water [72, 73]. They were shown to form active catalytic systems in Pd-mediated C-C coupling reactions between aryl iodides and alkynes (Castro-Stephens-Sonogashira reaction) [72, 74] and Rh-catalyzed hydroformylation of olefins in aqueous two-phase systems [75]. 

The catalytic hydroformylation of olefins is discussed in Chapter 5. The reaction of propylene with CO and H2 produces n-butyraldehyde as the main product. Isobutyraldehyde is a by-product °... 

The hydroformylation of olefins into aldehydes (oxosynthesis), discovered 1938 by O. Roelen,... 

A typical example of this is the dicobalt octacarbonyl catalyzed hydroformylation of olefins to yield aldehydes. According to the classical mechanism proposed by Heck and Breslow /29/ (Equations 28-31), the cobalt carbonyl reacts with hydrogen to form hydrido cobalt tetracarbonyl, which is in equilibrium with the coordinatively unsaturated HCo(C0)2. The tricarbonyl coordinates the olefin, and rearranges to form the alkyl cobalt carbonyl. 

Lindner et al. also prepared catalysts for the hydroformylation of olefins using a sol-gel-procedure to obtain rhodium complexes 5a-c (Figure 3.9). The bifunctional cocondensation agent (MeO)3Si(CH2)6Si(OMe)3 and a carbonylhydrido-... 

Fig. 4. Dissociative mechanism for the rhodium-triphenylphosphine-catalyzed hydroformylation of olefins (24-27).

Fig. 10. Proposed mechanism for the ruthenium-triphenylphosphine-catalyzed hydroformylation of olefins (36).

Thus far, we have discussed the transition metal complex-catalyzed hydrogenation of C=C, C=0, and C N bonds. In this section, another type of transition metal complex-mediated reaction, namely, the hydroformylation of olefins, is presented. 

P. G. Jessop, T. Ikariya, R. Noyori, Selectivity for Hydrogenation or Hydroformylation of Olefins by Hydrido-pentacarbonylmanganese(I) in Supercritical Carbon Dioxide , Organometallics 1995,14,1510-1513. 

I. T. Horvath, J. R abai, Facile Catalyst Separation without Water Fluorous Biphase Hydroformylation of Olefins , Science 1994, 266, 72. 

Abstract This chapter presents the latest achievements reported in the asymmetric hydroformylation of olefins. It focuses on rhodium systems containing diphosphites and phosphine-phosphite ligands, because of their significance in the subject. Particular attention is paid to the mechanistic aspects and the characterization of intermediates in the hydroformylation of vinyl arenes because these are the most important breakthroughs in the area. The chapter also presents the application of this catalytic reaction to vinyl acetate, dihydrofurans and unsaturated nitriles because of its industrial relevance. 

Secondary and tertiary amines can be obtained if the hydroformylation of olefins is conducted in the presence of primary and secondary amines under elevated hydrogen partial pressures. Here the rhodium catalyst is involved in both steps, the hydroformylation of an olefin as well as the hydrogenation of the imine or enamine resulting from a condensation of the oxo-aldehyde with the amine (Scheme 14). This combination of hydroformylation and reductive amination is also known as hydroaminomethylation and has been applied to the synthesis of various substrates of pharmaceutical interest [55-57] as well as to the synthesis of macrocycles [60-63] and dendrimers [64,65]. 

If the hydroformylation of olefins is conducted in the presence of aromatic hydrazines and Bronsted or Lewis acids indoles can be obtained directly in one pot [91-93,95]. Hydroformylation of the olefin gives an intermediate aldehyde, which is trapped immediately by the present aromatic hydrazine as an aromatic hydrazones similar to the formation of imines under hydroformylation conditions. Under acid mediation these aromatic hydrazones undergo a Fischer indolization, consisting of a [3,3]-sigmatropic rearrangement followed by a cyclization and elimination of ammonia (Scheme 38). 

Hydroformylation of hetero olefins such as carbonyl compounds is not known to proceed with significant levels of efficiency, whereas the hydroformylation of olefins has been developed to a sophisticated stage. Generally, aldehydes resultant from the latter process exhibit a low propensity to undergo further hydroformylation, with the exception of some activated aldehydes. The rhodium-catalyzed hydroformylation of formaldehyde is the key step in the synthesis of ethyleneglycol from synthesis gas. Chan et al. found... 

Although Eq. (3) indicates that CO absorption is required for aldehyde formation, it has been shown by Karapinka and Orchin 18) that at 25° and with a moderate excess of olefin the rate of reaction and the yield of aldehyde are similar when either 1 atm of CO or 1 atm of Nj is present. Obviously CO is not essential for the reaction and a CO-deficient intermediate, probably an acylcobalt tricarbonyl, can be formed under these conditions. The relative rates of HCo(CO)4 cleavage of tricarbonyl and tetracarbonyl are not known, and thus the stage at which CO is absorbed in the stoichiometric hydroformylation of olefins under CO is not known with certainty. Heck (19) has shown conclusively that acylcobalt tetracarbonyls are in equilibrium with the acylcobalt tricarbonyl ... 

Essentially the same sequence of reactions was proposed (22a) to explain the isomerization of olefins which accompanies the stoichiometric hydroformylation of olefins. In particular, it has been suggested that the active catalyst is cobalt hydrotricarbonyl, which first adds by Markownikoff addition and is then eliminated in the opposite direction ... 

The hydroformylation of olefins discovered by Otto Roelen [ 151 ] is one of the most important industrial homogeneously catalyzed reactions [152,153] for the synthesis of aldehydes with an estimated production of more than 9.2 million t in 1998 [ 153]. Hydroformylation is the addition of hydrogen and carbon monoxide to a C,C double bond. Industrial processes are based on cobalt or rhodiiun catalysts according to Eq. 1. The desired products are linear (n-) and branched (i-) aldehydes, in which the hnear products are generally favored for subsequent processing. 

Rhodium-catalyzed biphasic hydroformylation of olefins. The Ruhrchemie-Rhone Poulenc process for manufacturing... 

Rhodium(I) complexes with l,3-dimethylimidazolin-2-ylidene ligands were used in the hydroformylation of olefins. However, the activity and selectivity toward formation of branched versus linear aldehyde cannot compete with rhodium-phosphine systems. " Similar catalyst systems with the sterically more demanding l,3-dimesitylimidazolin-2-ylidene give higher branched/linear ratios for vinyl arenes (95 5), but the turnover frequency is still low compared to established systems [Eq. (52)]. ... 

Rh, are the base of active catalysts for CO hydrogenation and the hydroformylation of olefins. The presence of several promoters modifies their catalytic behavior and synergic effects on the base-metal have been observed Table 8.5 illustrates several examples in which homonuclear or heteronuclear carbonyl compounds have been used in the preparation of Co- or Co-Rh-based catalysts for the CO hydrogenation and/or hydroformylation reactions. 

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