Johnson hydroformylation

Rhodium Ca.ta.lysts. Rhodium carbonyl catalysts for olefin hydroformylation are more active than cobalt carbonyls and can be appHed at lower temperatures and pressures (14). Rhodium hydrocarbonyl [75506-18-2] HRh(CO)4, results in lower -butyraldehyde [123-72-8] to isobutyraldehyde [78-84-2] ratios from propylene [115-07-17, C H, than does cobalt hydrocarbonyl, ie, 50/50 vs 80/20. Ligand-modified rhodium catalysts, HRh(CO)2L2 or HRh(CO)L2, afford /iso-ratios as high as 92/8 the ligand is generally a tertiary phosphine. The rhodium catalyst process was developed joindy by Union Carbide Chemicals, Johnson-Matthey, and Davy Powergas and has been Hcensed to several companies. It is particulady suited to propylene conversion to -butyraldehyde for 2-ethylhexanol production in that by-product isobutyraldehyde is minimized. 

Triphenylphosphine -rhodium complex hydroformylation catalyst systems discovered by Wilkinson and developed by Union Carbide, Davy Powergas, and Johnson Matthey... 

This conclusion was challenged by Johnson (72), who followed the formation of isomeric aldehydes and isomeric olefins during the hydroformylation of 4-methyl-1-pentene. He found that 2-olefin was formed very rapidly under Oxo conditions and suggested that this did not affect the preferential formation of terminal aldehyde significantly, due to the fact that 2-olefin was so much less reactive to hydroformylation. These results have now been checked by Piacenti et al. (115), who found that 2-olefin was only rapidly formed if the rate of the reaction was sufficiently high that the solution was no longer saturated with carbon monoxide. By using a lower catalyst concentration in benzene solvent they were able to avoid this deficiency and found very little olefin isomerization. 

Johnson-Matthey Co. has reported that oleic acid methyl ester or linoleic acid methyl ester can be hydroformylated in micellar media using a water-soluble rhodium complex of monocarboxylated triphenylphosphine 45 as catalyst. As a further example, polyunsaturated linolenic acid methyl ester can be hydroformylated to the triformyl derivative with a selectivity of 55% with a Rh/TPPTS catalytic system in the presence of CTAB (Scheme 1.23). ... 

The idea of using monosulfonated or monocarboxylated triphenylphosphines in a biphasic reaction medium in the presence of amphiphilic reagents has already been patented, in 1981, by the Johnson-Matthey Corporation. However, the recycling of the catalyst complex published in this patent was not complete so that no technical process could be established in those early days of two-phase hydroformylation [47]. 

Phosphine modified cobalt catalysts permit the hydroformylation reaction to operate at lower pressure and produce a higher proportion of the normal isomer. Pressure is typically about 35 bars (500 psig) and the nor-mal/iso ratio is between 6 and 7. In the 1970s, Union Carbide in conjunction with Johnson Matthey and Davy McKee developed and improved oxo process based on a rhodium catalyst, modified with a triphenylphosphine (TPP) lipnd. 

Johnson Matthey have shown very recently that amphiphilic reagents such as dodecyltrimethylammonium bromide can have a significant effect on activity. Rh/4-diphenylphosphinobenzoic acid catalysts in water were active for the hydroformylation of a range of alk-l-enes at 80°C and 0.56 MPa. Selectivities of 100 and efficiencies of > 90% were obtained for the hydroformylation of hex-l-ene with low Rh losses. This system gave similar rates to those given by the Rhone Poulenc catalyst under lower H2/CO pressures (0.56 vs. 4 MPa). 

It is only relatively recently that data have started appearing on comprehensive studies of the use of intensified unit operations in industrially relevant reactions -particularly for bulk production. One such study involved a comparison between the stirred batch reactor process and a heat exchanger reactor (HEX-reactor). This was reported by a consortium involving Cardiff University, Givaudan, Johnson Matthey and Chart Energy and Chemicals (who supplied the HEX-reactor), and is presented in Enache et al. (2007). The hydroformylation reactions examined are used for the production of detergents, soap and surfactants - totalling millions of tonnes per annum. 

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