Heptenes hydroformylation

Scheme 4 shows a platinum catalyst 1 containing such a bis-SPO bidentate ligand anion, designed for the hydroformylation of ethylene and of 1-heptene, and various other, similarly built, platinum catalysts. Catalyst 1 has an activity comparable to that of the commercial cobalt catalysts that were used at the time and displays a higher selectivity for linear products than the cobalt-containing catalysts (66). Like the latter, the platinum complex exhibits hydrogenation activity to give, in part, alcohols in addition to aldehydes and also produces alkanes (an undesired reaction that implies a loss of feedstock). The catalysts are also active for isomerization, as are the cobalt complexes, and for internal heptene hydroformylation (Table 1), with formation of 60% linear products. 

Consider as a prototype the network 11.13 of n-heptene hydroformylation, keeping in mind that die arrows represent multistep pathways and that the reactions of higher straight-chain olefins involve still more parallel pathways of internal olefin isomers to aldehyde isomers and on to alcohol isomers. In such networks, all but one of the aldehyde-to-alcohol conversions involve the reaction of an aldehyde group on a secondary carbon atom, so that all these pathways can be assumed to involve essentially the same rate coefficients of their steps. Only the conversion of the straight-chain aldehyde (n-octanal to n-octanol in network 11.13) must be expected to occur with somewhat different rate coefficients. Likewise, all con-... 

Pla.tinum. Platinum catalysts that utilize both phosphine and tin(Il) haUde ligands give good rates and selectivities, in contrast to platinum alone, which has extremely low or nonexistent hydroformylation activity. High specificity to the linear aldehyde from 1-pentene or 1-heptene is obtained using HPtSnClgCO(1 1P) (26), active at 100°C and 20 MPa (290 psi) producing 95% -hexanal from 1-pentene. 

Heptenes. Heptenes, are used for the preparation of isooctyl alcohol [26952-21-6] by hydroformylation (see Oxo process). The heptenes... 

The formation of multinuclear clusters is much more favorable for rhodium than for cobalt. Additional evidence was obtained in comparative hydroformylation rate studies of 1-heptene and of cyclohexene at 75°C and 150 atm 1/1 H2/CO (19). For the acyclic olefin the kinetics followed the kinetic expression (except at low olefin) ... 

III,C, isomerization often accompanies hydroformylation. It has, however, been found that [(PhCN)2PdCl2] absorbed onto silica gel is 100 times more active for the isomerization of a-olefins, such as 1-heptene, than is the same complex alone (116). This implies some specific role for the silica gel. Attempts to use rhodium(III) chloride absorbed onto silica gel, alumina, activated charcoal, and diatomaceous earth as a-olefin isomerization catalysts showed that all these catalysts were unstable even at room temperature (100). 

J 0.2 Secondary Phosphines or Phosphites as Supramolecular Ligands 259 Table 10.1 Hydroformylation of 1-heptene with Pt(cod)2 as precursor and SPOs"... 

Heptenes. Heptenes, C7FL 7, are used for the preparation of isooctyl alcohol [26952-21-6] by hydroformylation (see Oxo process). The heptenes are prepared by very carefully controlled fractionation of polymer gasoline. Specifications generally call for >99.9% C content (including some paraffin that is also formed) to simplify processing. 

The hydroformylation of several olefins in the presence of Co2(CO)8 under high carbon monoxide pressure is reported. (S)-5-Methylheptanal (75%) and (S)-3-ethylhexanal (4.8%) were products from (- -)(S)-4-methyl-2-hexene with optical yields of 94 and 72%, respectively. The main products from ( -)(8)-2,2,5-trimethyl-3-heptene were (S)-3-ethyl-6,6-di-methylheptanal (56.6%) and (R)-4,7,7-trimethyloctanal (41.2%) obtained with optical yields of 74 and 62%, respectively. (R)(S)-3-Ethyl-6,6-dimethylheptanal (3.5% ) and (R)(S)-4,7,7-trimethyloctanal (93.5%) were formed from (R)(S)-3,6,6-trimethyl-l-heptene. (+/S)-l-Phenyl-3-methyl-1-pentene, under oxo conditions, was almost completely hydrogenated to (- -)(S)-l-phenyl-3-methylpentane with 100% optical yield. 3-(Methyl-d3)-l-butene-4-d3 gave 4-(methyl-d3)pentarwl-5-d3 (92%), 2-methyl-3-(methyl-d3)-butanal-4-d3 (3.7%), 3-(methyl-d3)pentanal-2-d2,3-d1 (4.3%) with practically 100% retention of deuterium. The reaction mechanism is discussed on the basis of these results. 

S)-4-Methyl-1 -hexene (12), (+) (S)-4-methyl-2-hexene, and ( + )(S)-5-methyl-l-heptene (12) were synthesized and subjected to hydroformylation under a relatively high carbon monoxide pressure. The main product in all instances was the result of formylation of the terminal carbon atom on or next to the double bond of the starting olefin. The optical yields of these products were about 94% (Table I). 

To demonstrate that optically active aldehydes from formylation of the methyl groups of optically active olefins can be obtained as main reaction products with good optical yields, we have studied the hydroformylation of ( + )(S)-2,2,5-trimethyl-3-heptene. None of the methyl groups of the tertiary butyl group were carbonylated. Primarily the reaction product was from carbonylation of the other two methyl groups present in the molecule (Table 1). (S)-3-Ethyl-6,6-dimethylheptanal... 

S)-l-Phenyl-3-methyl-l-pentene, initially synthesized to extend the data obtained with (+)(S)-2,2,5-trimethyl-3-heptene, under usual oxo conditions is almost completely hydrogenated with an optical yield of practically 100% while the hydroformylation products are barely detectable. 

R) (S)-3,6,6-Trimethyl-1-heptene. (R)(S)-3,6,6-Trimethyl-l-hept-ene has been hydroformylated in exactly the same conditions adopted for the hydroformylation of its isomer 2,2,5-trimethyl-3-heptene. The separation and identification of the reaction products have been made using the technique previously described. The results are reported in Table I. 

Hydroformylation of 2,6-dimethyl-6-hepten-2-ol produces hydroxycitronellal (equation 12).22 Subjecting allyl alcohol to hydroformylation reaction conditions with HCo(CO>4 yields only propanal, isomerization taking place more rapidly than hydroformylation.2 Phosphine-modified rhodium catalysts will convert allyl alcohol to butane-1,4-diol under mild conditions in the presence of excess phosphine, however (equation 13).5 30 31 When isomerization is blocked, hydroformylation proceeds normally (equation 14). An elegant synthesis of the Prelog-Djerassi lactone has been accomplished starting with the hydroformylation of an allylic alcohol (equation IS).32... 

The results of the hydroformylation of internal olefins are reported in Table 9. In the case of (Z)- and (E)-2-butene, the same fare of the unsaturated carbon atom is formylated with either a rhodium- or platinum (—)-DIOP-containing catalytic system. With the rhodium catalyst, when an acyclic olefin is used as the substrate, the same fare is always attacked, and it is only the notation but not the geometric requirement that is different for (E)-l-phenyl-1-propene. The only exception is represented by bicyclo[2,2,l]heptene. However, using (—)-CHIRAPHOS instead of (—)-DIOP, also bieyelo[2,2,l]heptene behaves like internal butenes. No regularity is observed for the cobalt or ruthenium (—)-DIOP catalytic systems. With the same system, only in 3 cases out of 15 the face of the prochiral atom preferentially formylated has different geometric requirements. 

Example 11.2. Streamlined network for hydroformylation of n-heptene catalyzed by phosphine-substituted cobalt hydrocarbonyl. In hydroformylation of straight-chain olefins with a phosphine-substituted cobalt hydrocarbonyl catalyst, the model must account for three complications that are absent with cyclohexene isomerization by migration of the double bond along the hydrocarbon chain, formation of isomeric aldehydes and alcohols, and condensation of the straight-chain aldehyde to "heavy ends (chiefly an alcohol of twice the carbon number, such as 2-ethylhexanol from propene via n-butanal and a C8 aldol). A streamlined network for n-heptene is ... 

An interesting catalytic system was described by Pinke in a patent of 1975 13). This system combines a complex of a group 8 transition metal with an aluminum hydride. Such catalysts can perform the hydroformylation of mixtures of terminal and internal alkenes to the corresponding linear aldehyde and alcohol. One example is related to the [RuCl2(PBu3)3] + AlHEt2 system which transforms, at 120 bar (Hj/ CO = 1/2) and 150°C over 24 hours, heptene into octanal and octanol. Linear products were detected exclusively. 

CH3CH=CH(CH2)3CH3 (2-heptene) Comparison of cis- and Irans- hydrocarboxylation rates 14.6.4.3. Relative rate of hydroformylation (table) 14.6.3.2. 

For long-term stability, the SAPC must remain assembled. To test for this type of stability, it was investigated whether the components can self-assemble. The rhodium complex HRh(CO)(TPPTS)3, TPPTS and water were loaded into a reactor with cyclohexane and 1-heptene. The reactor was pressurized with approx. 70 bar H2 + CO (CO H2, 1 1) and heated with stirring to 100°C. A second experiment was carried out in a manner similar to the one previously described except that CPG-240 was added also. The components of the SAPC self-assemble to form an SAPC and carry out the hydroformylation reaction [13]. Upon termination of the reaction, the solid collected contained HRh(CO)(TPPTS)3 and TPPTS. This test indicates that, under the conditions of the experiment, the individual components of the SAPC are more stable assembled in an SAPC configuration than separated. Therefore, the reverse, i.e., the separation of the solution and complex from the support, is not likely to happen under reaction conditions. 

The water content of HRh(CO)(TPPTS)3-based SAPCs has a great influence on their performance. For example, when 1-heptene is hydroformylated, the TOF increases by two orders of magnitude when the water content of the catalyst increases from approx. 2.9 wt.% to approx. 9 wt.% (Table 2). 

Catalytic hydroformylation of bicyclo[2.2.1]heptene with [Pt(C2H4)[Pg.305]

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