Mixed ruthenium-tin boride catalysts for selective hydrogenation of fatty acid esters to fatty alcohols

Abstract

A new catalyst system, ruthenium-tin boride, was developed for the selective hydrogenation of fatty acid esters to fatty alcohols at 270 °C and a pressure of 640 psi of H2. The yields of fatty alcohols from various long-chain fatty acid esters varied from 70% to 89%. The catalyst had an atomic ratio of ruthenium to tin of 1:1 and could be unsupported or supported on 7-Al203. The importance of the method of preparation using sodium borohydride as the reductant was also demonstrated. A tentative mechanism for the selective activation of the ester carbonyl by the new catalyst system was proposed, based on the surface characterization of the catalysts reported elsewhere.Hydrogenolysis of fatty acid esters to fatty alcohols is a high-pressure reaction. Fatty alcohols are important products that find extensive use for making surfactants of all kinds. Industrially, fatty alcohols are produced using copper chromite based catalysts. These catalysts operate at a high pressure of 4000 psi at temperatures of 250-300 °C. In the literature, only two other catalyst systems, palladium-rhenium and rhodium-tin, have been reported (Traverse et al., 1984;Snappe and Bourneville, 1982) as catalysts for the hydrogenolysis of esters in the pressure range 150-750 psi.

Selective hydrogenation of oleic acid to 9‐octadecen‐1‐ol: Catalyst preparation and optimum reaction conditions

“…There are a few catalyst systems reported in the literature (pertaining to the production of oleyl alcohol by catalytic hydrogenation of oleic acid or methyl oleate) that can pre~ serve the double bond of the oleic acid or methyl oleate dtm ing the process of hydrogenation, but all of these processes also are carried out under high pressure {>15.2 MPa) and high temperature (250°C) (4,5). Recently, Narasimhan et aL (6)(7)(8) showed that methyl oleate could be selectively hydr~ genated to oleyl alcohol by using a mixed ruthenium-tin boride catalyst system under relatively low pressure (4.5 MPa) and a temperature of 270°C. They claimed that boride is essential in their process, but they have yet to clarify its role Furthermor~ most catalysts which are used in such a hydrogenation often behave differently depending on whether the substrate is ester or acid.…”

“…ported catalyst system that can selectively reduce benzene to cyclohexene by the complexing agent-assisted sol-gel (chemical mixing) methoc[ Such catalysts show specific behavior different from the corresponding impregnation catalyst (9). Alsa tin has been reported to have the ability to preserve the double bond of methyl oleate during hydrogenation (6)(7)(8). Based on these findings we investigated the behavior of ruthenium-tin supported catalyst, prepared by the complexing agent~assisted sol-gel method, on the selective hydrogenation of oleic acid to ~octadecen-l~L Our objective was to overcome the drawbacks in the above mentioned processes and to develop a new and practical method of producing 9-octadecen-l-ol from oleic acid under mild conditions.…”

Selective hydrogenation of fatty acids and methyl esters of fatty acids to obtain fatty alcohols–a review

“…Catalysts of the type Ru–Sn–B, present a good selectivity for the conversion of fatty esters to the correspondent unsaturated fatty acids . The hydrogenation of methyl oleate over 2%Ru/TiO 2 , 4.7%Sn/TiO 2 and 2%Ru–4.7%Sn/TiO 2 catalysts was studied by Corradini et al These studies revealed that addition of ruthenium negatively affects the activity of the catalyst in the hydrogenation of methyl oleate.…”

Influence of Preparation Modes on Pt–Ni/CNTs Catalysts Used in the Selective Hydrogenation of Cinnamaldehyde to Hydrocinnamaldehyde

“…3. From catalyst, Ru-Sn-B, which was prepared by reducing metal salts with NaBH 4 [39]. It was reported that Ru-Sn-B/ Al 2 O 3 performed better in selective hydrogenation of fatty acid esters to fatty alcohols than Ru-Sn/Al 2 O 3 prepared by H 2 reduction.…”