Aqueous-phase catalytic hydrogenation of methyl esters of Cynara cardunculus alternative low-cost non-edible oil: A useful concept to resolve the food, fuel and environment issue of sustainable biodiesel

Cynara cardunculus a perennial thistle grown wild on marginal lands abandoned from agricultural use without competition with food plants is recently recognized as a low-cost multipurpose energy crop with a high potential for industrial applications inter alia biodiesel production. The selective hydrogenation of polyunsaturated methyl esters of C. cardunculus alternative non-edible oil to their monounsaturated counterparts catalyzed by industrially applied water-soluble Ru/TPPTS complexes [TPPTS=trisulfonated triphenylphosphine, P(C6H4-m-SO3Na)3] in green aqueous media to obtain biodiesel with superior oxidative stability energy and environmental performance at a low pour point could represent an elegant and useful approach to resolve the food, fuel and environment trilemma of sustainable biodiesel production. © 2013 Elsevier B.V

Production of hydrogenated methyl esters of palm kernel and sunflower oils by employing rhodium and ruthenium catalytic complexes of hydrolysis stable monodentate sulfonated triphenylphosphite ligands

This study deals with the hydrogenation of renewable polyunsaturated methyl esters of palm kernel and sunflower oils to the saturated (C18:0) methyl stearate (MS) catalyzed by rhodium and ruthenium complexes modified with hydrolysis stable monodentate sulfonated triphenylphosphite (STPP) ligands under mild reaction conditions in the absence or presence of organic solvents. Superior selectivities up to 95.8. mol% of MS were achieved by Rh/STPP catalysts compared with the much lower selectivities (28.0-43.2. mol%) of MS obtained by rhodium catalysts modified with conventional triphenylphosphite or triphenylphosphine ligands. The bulkiness of transition metal STPP catalytic system which is in the form of a triisooctylammonium salt offers the possibility of the easy separation of the catalyst from the reaction mixture by means of a membrane. The hydrogenation reaction of the polyunsaturated C18 esters part of palm kernel oil and sunflower oil methyl esters toward the desired saturated product MS is an interesting catalytic reaction because it could acts as a model reaction for studying the hydrogenation of edible vegetable oil triglycerides to hardfats. Hardfats can be further subjected to interesterification reactions with liquid edible vegetable oils to yield foodstuffs with zero amounts of trans-fats. Very recent investigations have questioned whether there really are direct associations between hardfat consumption and a higher cardiovascular disease risk. Furthermore, MS could be used as a starting material of selective heterogeneous catalytic hydrogenolysis reaction of the C18:0 fatty ester to the corresponding saturated C18:0 stearyl alcohol which is an important industrial fatty alcohol. © 2014 Elsevier B.V

Catalytic conversions in aqueous media: Part 3. Biphasic hydrogenation of polybutadiene catalyzed by Rh/TPPTS complexes in micellar systems

Water-soluble Rh/TPPTS complexes [TPPTS = P(C6H4-m-SO3Na)3] are active catalysts (TOF > 1200 h-1) for the biphasic hydrogenation of the completely water-insoluble heavy polybutadiene (PB) in single micelles formed by the cationic surfactant dodecyltrimethylammonium chloride (DTAC), or mixed micelles created by DTAC with either non-ionic or anionic surfactants. The reaction proceeds under mild conditions (T = 100 °C, PH2 = 20 bar) at a molar ratio of P/Rh = 3 and C{double bond, long}C units/Rh = 1000 within 20 min and at a rhodium concentration of only 10 ppm in water. The pH of the aqueous catalyst solution markedly influenced the activity. High catalytic activities were achieved under neutral conditions whereas at acidic or basic conditions the catalytic activity dramatically decreased. The hydrogenation rate depends critically on the microstructure of PB and the nature of micellar catalysis. The 1,4-units content of PB plays a major role for performing the catalytic hydrogenation reaction in single or mixed micellar systems for obtaining maximum reactivity. When the PB possesses a high 1,4-units content (98.0 wt% of 1,4-units and 2.0 wt% of 1,2-units) higher reaction rates were achieved in mixed micellar systems created by DTAC/Brij-35 surfactants compared to the rates observed in single DTAC micelles. In contrast, with PB starting material consisting of 61.0 wt% of 1,2-units and 39.0 wt% of 1,4-units higher reaction rates were obtained in single DTAC micelles compared to those rates achieved in mixed micellar systems. © 2009 Elsevier B.V. All rights reserved

Beitraege zur Rhodium-katalysierten Hydroformylierung mittel- und hoehermolekularer #alpha#-Olefine im Ein- und Zweiphasen-System

SIGLEAvailable from TIB Hannover: DW 827 / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekDEGerman

Catalytic conversions in aqueous media. Part 2. A novel and highly efficient biphasic hydrogenation of renewable methyl esters of linseed and sunflower oils to high quality biodiesel employing Rh/TPPTS complexes

An unusual high catalytic activity (TOF = 117,000 h-1) and high catalyst productivity (TON = 9,700) have been achieved in the first example of partial hydrogenation of renewable polyunsaturated crude methyl esters of linseed and sunflower oils catalyzed by water soluble Rh/TPPTS complexes [TPPTS = P(C6H4-m-SO3Na)3] in aqueous/organic two-phase systems to afford monounsaturated fatty esters which is biodiesel first generation of improved oxidative stability, energy and environmental performance at a low pour point. This exceptionally high catalytic activity contrast with the general perception that industrially applied water soluble Rh/TPPTS catalysts normally exhibit very low rates in the conversions of higher molecular weight starting materials in aqueous/organic two-phase systems. © 2007 Springer Science+Business Media, LLC

Catalytic conversions in green aqueous media. Part 8: Partial and full hydrogenation of renewable methyl esters of vegetable oils

This article reviews the partial hydrogenation of renewable polyunsaturated methyl esters of linseed, sunflower, Cynara cardunculus and soybean oils into their monounsaturated counterparts which is upgraded biodiesel fuel employing highly active and selective water-soluble rhodium, ruthenium and palladium TPPTS complexes and by water-dispersible palladium(0) nanoparticles stabilized by water-soluble nitrogen-containing ligands which possess even higher activities than those exhibited by Pd/TPPTS benchmark catalysts in aqueous/organic two-phase systems. Furthermore, this article presents a novel study on the full hydrogenation of polyunsaturated methyl esters of sunflower and palm kernel oils to obtain up to 99.0 mol% methyl stearate (MS) using water-soluble Rh-and Ru-TPPTS catalytic complexes under mild reaction conditions in aqueous/organic two-phase systems. The full hydrogenation reaction of polyunsaturated FAMEs into MS is an interesting catalytic reaction because MS is an industrial feedstock for the manufacture of specialties such as surfactants, emulsifiers, etc., and could also act as a model reaction for studying the full hydrogenation of edible oils to saturated fats to be further subjected to interesterification reactions with liquid edible vegetable oils to yield foodstuffs with zero amounts of trans-fats especially after publication of results of very recent investigations which have questioned whether there really are direct associations between saturated fat consumption and a higher cardiovascular disease risk. © 2014 Elsevier B.V. All rights reserved

Superior aqueous-phase catalytic hydrogenation activity of palladium modified with nitrogen-containing ligands compared with the TPPTS benchmark modifier in micellar nanoreactors

Exceptionally high catalytic activities (TOF=110,000h-1) have been achieved by water-dispersible palladium(0) nanoparticle catalysts stabilized by water-soluble nitrogen-containing ligands in the hydrogenation of renewable polyunsaturated methyl esters of soybean oil (MESBO) to their monounsaturated counterparts in aqueous/organic micellar systems. Palladium(II) chloride catalyst precursors exhibited a superior aqueous-phase catalytic activity with various nitrogen-containing ligands inter alia bathophenanthrolinedisulfonic acid disodium salt [(BPhDS) (TOF=71,000h-1)], diethylenetriaminepentakis (methylphosphonic acid) (TOF=68,000h-1), ethylenediaminetetraacetic acid tetrasodium salt (TOF=50,000h-1) compared with the TPPTS benchmark ligand modifier (TOF=34,000h-1) in this environmentally friendly biphasic catalytic hydrogenation reaction. Mercury poisoning experiments of preformed Pd/BPhDS catalysts proved the heterogeneous nature of this catalytic hydrogenation system. Dynamic light scattering experiments evidenced the presence of micellar nanoreactors with in situ prepared [Pd(OAc)2]3/BPhDS catalyst possessing an average hydrodynamic radius of 36nm and with preformed and recycled PdCl2/BPhDS catalyst with an average hydrodynamic radius of 57nm. The apparent activation energy of preformed palladium(0) nanoparticle hydrogenation catalysts stabilized by BPhDS in micellar systems was calculated to 23.7kJ/mol which is of the same order of magnitude as reported earlier for palladium(0) nanoparticles stabilized by dendritic core-multishell architectures. A recycling experiment at 120°C showed that the activity of palladium(0) nanoparticle catalyst stabilized by BPhDS in micellar systems in aqueous media remained high in a consecutive run indicating a stable palladium(0) catalytic nanoparticle system which is remarkable when one considers that transition metal(0) catalytic nanoparticles are usually applied at much lower temperatures due to their lower stabilities. © 2013 Elsevier B.V

Catalytic conversions in aqueous media: A novel and efficient hydrogenation of polybutadiene-1,4-block-poly(ethylene oxide) catalyzed by Rh/TPPTS complexes in mixed micellar nanoreactors

Exceptionally high catalytic activities (TOF > 840 h-1) were achieved in the aqueous phase hydrogenation of polybutadiene-1,4-block- poly(ethylene oxide) (PB-b-PEO) catalyzed by water-soluble Rh/TPPTS complexes [TPPTS = P(C6H4-m-SO3Na)3] in mixed micellar nanoreactors formed by dodecyltrimethylammonium chloride along with PB-b-PEO especially when n-hexane was added to the reaction system. This is the first example of a catalytic hydrogenation of an unsaturated polymer using water-soluble transition metal TPPTS complexes in aqueous media. Using Rh/TPPTS catalysts high activities were observed in the hydrogenation of PB-b-PEO in mixed micelles whereas in single micelles the activities were lower. Dynamic light scattering experiments showed the presence of mixed nanomicelles with smaller hydrodynamic radii compared to the radii of single micelles. A model of a mixed micellar nanoreactor was proposed to rationalize the observed results. The hydrogenation reaction was shown to be homogeneously catalyzed by Rh/TPPTS complexes generated in situ from RhCl3·3H2O and TPPTS under the reaction conditions. A recycling experiment showed that the catalytic activity remained high in a consecutive run even at a rhodium concentration of only 1 ppm in water. © 2005 Elsevier B.V. All rights reserved

Low trans-isomers formation in the aqueous-phase Pt/TPPTS-catalyzed partial hydrogenation of methyl esters of linseed oil

Very low formation of both undesired products namely trans-C18:1 esters and the fully saturated methyl stearate (MS) with high catalytic activities (TOF = 6820 h−1) under mild reaction conditions have been achieved by water-dispersible platinum(0) nanoparticle catalysts stabilized by TPPTS ligands and the zwitterionic phospholipid surfactant lecithin in the partial hydrogenation of polyunsaturated methyl esters of linseed oil (MELO) into their monounsaturated counterparts in aqueous/organic micellar reactors. The reaction rate was independent of the stirring rate ensuring that mass transfer was not rate determining. The apparent activation energy of the Pt/TPPTS catalyst was calculated and amounts a low value of 17.8 kJ/mol. Employing Pt/TPPTS catalysts the starting material MELO possessing an iodine value (IV) of 202 was reduced to IV = 85 and contained only 2.4 mol% of trans-C18:1 esters. In contrast, in the traditional industrial partial hydrogenation process of soybean oil possessing an IV of 130 reduced over commercial Ni-based catalyst to IV = 80 the trans-fats content was ∼30 mol% whereas with a further reduction to IV = 70 to produce all-purpose shortenings the trans-fats level reached a higher value of ∼45 mol%. In the aqueous-phase catalysis, in the range of 55–70 IVs for the hydrogenated products of MELO the Pt/TPPTS catalysts gave the least amount of trans-C18:1 esters followed by Rh/TPPTS and then by Pd/TPPTS complexes. Interestingly, with Pt/TPPTS catalysts the formation of MS was very low compared with Pd/TPPTS and Rh/TPPTS systems. Over highly active heterogeneous Pt/Al2O3 (5 wt.%) catalysts the formation of trans-C18:1 esters was low whereas the content of MS was high (37.7 mol%) compared with the very low formation of MS (2.93 mol%) with Pt/TPPTS catalysts. Even at a reduction level of IV = 72 a sufficient amount of C18:3 esters (2.9 mol%) still remained over Pt/Al2O3 catalysts whereas with Pt/TPPTS at IV = 70 the conversion of C18:3 esters was quantitative. A recycling experiment at a higher temperature of 80 °C showed that the catalytic activity of water-dispersible platinum(0) nanoparticle catalysts stabilized by TPPTS remained high in a consecutive run and possess the potential to be recycled without any loss of catalytic activity. This partial hydrogenation reaction of MELO employing platinum(0) nanoparticle-TPPTS-lecithin-stabilized catalytic systems is an interesting model of a catalytic reaction for studying the selective partial hydrogenation of edible vegetable oils to foodstuffs with very low or zero amounts of both undesired products namely trans-fats and fully saturated fats employing environmentally attractive aqueous/organic two-phase systems. © 2017 Elsevier B.V