To compare a continuous hydrogenation system with batch hydrogenation, soybean oil was treated with Pd and Ni catalysts in a fixed-bed system under conditions that gave trickle flow. The influence of processing variables such as space velocity, pressure, temperature and hydrogen flow on the selectivity, specific isomerization and the activity was investigated. Both the Pd and Ni catalysts gave significantly lower specific isomerization(trans isomer per drop in Iodine Value) when compared to reported values for batch hydrogenation with similar type catalysts. The linolenate and linoleate selectivities were also significantly lower. Heterogenized homogeneous Pd-on-polystyrene catalyst gave lower specific isomerization formation and higher selectivity than carbon-supported Pd catalyst at same conditions. This work indicates that Pd-on-styrene, Pd-on-carbon and extruded Ni catalysts, in fixed-bed continuous hydrogenation can produce soybean oil of desirable composition after further optimization.

Fixed-Bed Continuous Hydrogenation of Soybean Oil With Palladium-Polymer Supported Catalysts

Mesoporous silica (SBA-15) synthesized by using Pluronic123 as the structure-directing template was functionalized by imidazolium-based ionic liquid precursors. Silver salts were then immobilized onto the supported ionic liquids using the incipient wetness impregnation technique. The separation of unsaturated species was achieved through the reversible and specific interaction between silver ions and carbon–carbon double bonds. This adsorbent was examined for the selective separation of polyunsaturated triacylglycerols (PUTAG) using High Pressure Liquid Chromatography (HPLC) with Evaporative Light Scattering Detection (ELSD) as the quantification methodology. AgBF4/SBA15·HPSiOEtIM·PF6 showed an adsorption capacity for linolenin of about 217 mg adsorbed/gram of sorbent. This adsorbent had good selectivity and a high capacity for the most highly unsaturated triacylglycerol when applied to a mixture of triacylglycerols with varying degrees of unsaturation. Consequently, a stepwise methodology was also developed to increase the recovery of the adsorbed components. This adsorbent retained its selectivity and capacity when recycled up to five times. © 2009 American Institute of Chemical Engineers Biotechnol. Prog., 2009

Selective extraction of polyunsaturated triacylglycerols using a novel ionic liquid precursor immobilized on a mesoporous complexing adsorbent.

Cationic rhodium (I) complexes of the type [(NBD)RhL2]+ ClO4
 − (NBD, norbornadiene; L, triphenyl phosphine or diphenyl phosphino ethane) have been studied as catalysts for the isomerization of methyl linoleate and safflower oil. The catalysts gave very good yields of conjugated products with both oil and methyl linoleate. Isomerization could be carried out under very mild conditions (55–65 C, 1 atm N2). Although the catalyst undergoes transformation in the course of the reaction, it maintains its catalytic activity. In fact, the catalysts isolated from the reaction with safflower oil were recycled with practically no loss of activity.

Catalytic isomerization of safflower oil with rhodium complexes

Zahlreiche Prozesse der industriellen Fettchemie werden mit Hilfe Ubergangsmetall-haltiger Katalysatoren durchgefuhrt, wobei meist heterogene Katalysatoren eingesetzt werden. Der vorliegende Ubersichtsartikel widmet sich den Anwendungsmoglichkeiten der homogenen Ubergangsmetallkatalyse in der Fettchemie. Die Vorteile der homogenen Ubergangsmetallkatalyse, z. B. die oftmals hohe Selektivitat sowie die zumeist milden Reaktionsbedingungen, werden in der Petrochemie schon in zahlreichen Prozessen genutzt, wahrend in der Oleochemie bisher keine analogen industriellen Prozesse existieren. Forschungsergebnisse der letzten beiden Jahrzehnte zeigen, das die Vorteile der homogenen Ubergangsmetallkatalyse auch in der Fettchemie angewendet werden konnen: Bekannte Reaktionen konnten verbessert und neuartige Reaktionen entwickelt werden. In dem vorliegenden Review wird uber einige wichtige Beispiele detaillierter berichtet, so z. B. uber die Selektivhydrierung mehrfach ungesattigter Fettstoffe und uber die Moglichkeiten zur selektiven Isomerisierung von Doppelbindungen. Ebenfalls erlautert werden Oxidationsreaktionen, Umsetzungen mit Kohlenmonoxid, metathetische Umwandlungen, CC-Verknupfungen, Telomerisationen und Additionen an die Doppelbindung ungesattigter Fettstoffe.



Homogeneous Transition Metal Catalysis in Oleochemistry



Numerous processes in industrial oleochemistry are carried out using transition metal catalysts. However, in most cases the catalysts applied are heterogeneous. The present review considers the huge number of possible applications of homogeneous transition metal catalysis in oleochemistry. The advantages of homogeneous transition metal catalysis are the high selectivity and the mild reaction conditions. These advantages are often used in petrochemistry, but in industrial oleochemistry exist no similar developments. The results of the laboratory research in the last two decades prove that the special properties of homogeneous transition metal catalysts can be applied in oleochemistry too. Well known chemical reactions could be improved and new reactions could be developed. The present review refers some of the most interesting reaction types, e. g. the selective hydrogenation of manifold unsaturated fatty acids or the possibilities to isomerize the double bonds selectively. Oxidation reactions, reactions with carbon monoxide, metathesis, CC-linkage reactions, telomerizations and additions to the double bonds of unsaturated fatty compounds will also be presented.

Anwendungsmöglichkeiten der homogenen Übergangsmetallkatalyse in der Fettchemie

Transition metals in organic synthesis: hydroformylation, reduction and oxidation: Annual survey covering the year 1986☆

Different Rh complex catalysts were compared for the hydrogenation of methyl sorbate and linoleate in the absence of solvents. At 100 C and 1 atm H2 the following complexes, RhCl(Ph3 P)3 (Ph= phenyl), [RhClNBD]2 (NBD=norbornadiene) and RhH(CO)(Ph3P)3, produced mainly methyltrans-2-hexenoate (34 to 56%). Their diene selectivity was not particularly high as they produced 14 to 41% methyl hexanoate. With RhCl(Ph3 P)3 constant ratios between rates of methyl sorbate disappearance and formation of methyltrans-2- andtrans-3-hexenoate indicate approximately the same activation energy for 1,2-addition of H2 on the Δ4 double bond of methyl sorbate and for 1,4-addition to this substrate. In the hydrogenation of methyl linoleate with RhCl(Ph3 P)3, the kinetic curves were simulated by a scheme in which 1,2-reduction was more than twice as important as 1,4-addition of H2 via conjugated diene intermediates. Although the complexes RhCl(CO)(Ph3 P)3 and [Rh(NBD)(diphos)]+PF6 (diphos=diphosphine) were inactive in the hydrogenation of methyl sorbate, they catalyzed the hydrogenation of methyl linoleate at 100 C and 1 atm. Catalyst inhibition apparently was caused by stronger complex formation with methyl sorbate than with the conjugated dienes formed from methyl linoleate.

J. A. Heldal

Papers

Homogeneous hydrogenation of dienes with rhodium complexes