Hydroformylation linoleic methyl ester

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). ... 

Epoxidation of oleic and linoleic acid was readily achieved by treatment with the acetonitrile complex of hypofluorous acid (55). Phase-transfer-catalyzed biphasic epoxidation of unsaturated triglycerides was accomplished with ethylmethyldioxirane in 2-butanone (56). The enantioselective formation of an a,P-epoxy alcohol by reaction of methyl 13()S)-hydroperoxy-18 2(9Z,llfi) with titanium isopropoxide has been reported (57). An immobilized form of Candida antartica on acrylic resin (Novozyme 435) was used to catalyze the perhydrolysis and the interesterification of esters. Unsaturated alcohols were converted with an ester in the presence of hydrogen peroxide to esters of epoxidized alcohols (e.g., epoxystearylbutyrate) directly (58). Homoallyl ethers were obtained from olefinic fatty esters by the ethylaluminium-in-duced reactions with dimethyl acetals of formaldehyde, acetaldehyde, isobutyralde-hyde, and pivaldehyde (59). Reaction of 18 2(9Z, 12Z) with 50% BF3-methanol gave monomethoxy and dimethoxy derivatives (60). A bulky phosphite-modified rhodium catalyst was developed for the hydroformylation of methyl 18 1 (9Z)and 18 1(9 ), which furnished mixtures of formylstearate and diformylstearate (61). 

By the effect of a Rh/C catalyst modified with PPhg at 140 bar syngas pressure and 110 °C on a complex substrate mixture of fatty acid methyl esters with one or more double bonds, besides the formation of monoformyl stearate, some diformy-lated products were found [34]. Moreover, unsaturated monoformyl esters were detected together with triformyl esters derived from methyl linolenate. The formation of 1,4-diformyl esters in the hydroformylation of methyl linoleate over the 1,3-diformyl isomers was explained by the thermodynamic stability of the transient Rh-acyl complex A over the chelate B with a smaller ring size. 

Up until now, mostly pure substrates such as methyl oleate and its -isomer, methyl elaidate, have been tested as model substrates for hydroformylation, but in a few cases, linoleates, linolenates, and esters of ricinoleic acid have also been investigated (Figure 6.10). Oleic acid can be derived from new sunflower, linoleic acid from soybean, linolenic acid from linseed, and ricinoleic acid from castor oil. The long-chain mono-unsaturated fatty acid erucic acid (C22) can be extracted from old rapeseed oil. 

---