- Integrated extraction and catalytic upgrading of microalgae lipids in supercritical carbon dioxide
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Fatty acids from microalgae are attractive compounds for catalytic upgrading to chemicals, but their extraction often requires multi-step procedures and the use of various organic solvents. To relieve this bottleneck, we propose a straightforward approach of combined extraction and catalytic functionalization via olefin cross-metathesis (ethenolysis and butenolysis) in supercritical CO2 (scCO2). This is demonstrated for Phaeodactylum tricornutum microalgae biomass. ScCO2 at optimum conditions (90 °C, 620 atm, ρ(CO2) = 0.90 g mL-1) extracted the lipids selectively and quantitatively from previously disrupted cells, while organic solvent extraction for comparison additionally extracted polar diacylglycerides and chlorophylls. In a one-pot approach, olefin cross-metathesis of the unsaturated fatty acids (FA16:1, FA18:1 and FA20:5) by alkenolysis yielded the desirable mid-chain olefin and unsaturated ester products. The product spectrum compares to alkenolysis of individual model compounds in scCO2 as well as of separately scCO2 extracted microalgae oil. Both these ethenolysis and butenolysis proceed with conversions of more than 81% and high selectivities to the desired products. This biorefinery approach was further illustrated by the simultaneous extraction and catalytic isomerizing alkoxycarbonylation in scCO2.
- Zimmerer, Julia,Pingen, Dennis,Hess, Sandra K.,Koengeter, Tobias,Mecking, Stefan
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supporting information
p. 2428 - 2435
(2019/05/21)
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- Fishing for the right catalyst for the cross-metathesis reaction of methyl oleate with 2-methyl-2-butene
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The activity of various Ru-alkylidene olefin metathesis catalyst types on the outcome of cross-metathesis of methyl oleate with 2-methyl-2-butene was studied.
- Sytniczuk,Kajetanowicz,Grela
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p. 1284 - 1296
(2017/05/05)
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- Using N-nitrosodichloroacetamides to conveniently convert linear primary amines into alcohols
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The reported rearrangement of N-nitrosodichloroacetamides provides a practicalmethod for converting primary amines into primary alcohols. The reaction sequence is operationally simple, requires only a single purification, and is compatible with a number of common functional groups. Mechanistic studies of the nitrosylation and rearrangement reactions illustrate the increased utility of dichloroacetamides compared to various other amides for this transformation.
- Macarthur, Nicholas S.,Wang, Linshu,Mccarthy, Blaine G.,Jakobsche, Charles E.
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supporting information
p. 2014 - 2021
(2015/08/18)
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- Rhodium versus iridium catalysts in the controlled tandem hydroformylation-isomerization of functionalized unsaturated fatty substrates
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The hydroformylation of 10-undecenitrile (1) and related unsaturated fatty substrates (H2C=CH(CH2)7CH2R; R=CO2Me, CH2Br, CHO) has been studied with rhodium, iridium, ruthenium, and palladium biphephos catalysts. The reactions proceeded effectively with all four systems, with high selectivities for the linear aldehyde (ratio of linear/branched aldehydes=99:1). The biphephos-bis[chloro(cyclooctadiene)iridium] system showed a non-optimized hydroformylation turnover frequency (TOFHF) of 770h-1 that was only approximately 5times lower than that of the rhodium-based system (TOFHF=3320h-1); the palladium and ruthenium biphephos systems were less active (TOFHF=210 and 310h-1, respectively). Upon recycling, remarkable productivities were achieved in both cases (TON≈58-000mol(1/1-int)-mol(Ir)-1 and 250-000mol(1/1-int)-mol(Rh)-1, in which int=internal olefin). Competitive isomerization of terminal to internal olefins occurred with these catalysts. Iridium biphephos systems allowed slightly better control of the distribution of the internal isomers than the rhodium biphephos catalyst, with higher ratios of 9-/8-undecenitrile (1-int). Place your bets now: Iridium-biphephos catalysts are highly effective in the controlled tandem isomerization-hydroformylation of 10-undecenitrile and related functionalized unsaturated fatty substrates.
- Ternel, Jrmy,Couturier, Jean-Luc,Dubois, Jean-Luc,Carpentier, Jean-Franois
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p. 513 - 520
(2015/03/04)
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- Chelating Ruthenium Phenolate Complexes: Synthesis, General Catalytic Activity, and Applications in Olefin Metathesis Polymerization
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Cyclic Ru-phenolates were synthesized, and these compounds were used as olefin metathesis catalysts. Investigation of their catalytic activity pointed out that, after activation with chemical agents, these catalysts promote ring-closing metathesis (RCM), enyne and cross-metathesis (CM) reactions, including butenolysis, with good results. Importantly, these latent catalysts are soluble in neat dicyclopentadiene (DCPD) and show good applicability in ring-opening metathesis polymeriyation (ROMP) of this monomer. Olefin metathesis catalysis: Investigation of the catalytic activity of Ru phenolate catalysts pointed out that, after activation with chemical agents, these catalysts promote ring-closing metathesis (RCM), enyne, and cross-metathesis (CM) reactions, including butenolysis, with good results (see scheme, Mes=2,4,6-trimethylphenyl, Cy=cyclohexyl). The phenolanate catalysts, well soluble in dicyclopentadiene (DCPD), also show good applicability in ring-opening metathesis polymerization (ROMP) of this monomer.
- Koz?owska, Anna,Dranka, Maciej,Zachara, Janusz,Pump, Eva,Slugovc, Christian,Skowerski, Krzysztof,Grela, Karol
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p. 14120 - 14125
(2016/02/18)
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- SYNTHESIS OF TERMINAL ALKENES FROM INTERNAL ALKENES VIA OLEFIN METATHESIS
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This disclosure relates generally to olefin metathesis, and more particularly relates to the synthesis of terminal alkenes from internal alkenes using a cross-metathesis reaction catalyzed by an olefin metathesis catalyst. According to one aspect, for example, a method is provided for synthesizing a terminal olefin, the method comprising contacting, in the presence of a ruthenium alkylidene metathesis catalyst, an olefinic substrate comprised of at least one internal olefin with a cross metathesis partner comprised of an alpha olefinic reactant, under reaction conditions effective to allow cross-metathesis to occur, wherein the reaction conditions include a reaction temperature of at least 35 °C. The methods, compositions, reactions and reaction systems herein disclosed have utility in the fields of catalysis, organic synthesis, and industrial chemistry.
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Page/Page column 41-42; 45-46
(2008/06/13)
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- METHODS OF MAKING MONOUNSATURATED FUNCTIONALIZED ALKENE COMPOUNDS BY METATHESIS
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Described is a method of chemically modifying a starting composition comprising polyunsaturated alkene compounds in order to convert at least a portion of the polyunsaturated alkene compounds into functionalized monounsaturated alkene compounds. The separated monounsaturated alkene compounds may be useful, for example, as a starting material in the synthesis of organic chemicals such as diacids, diesters, and the like.
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Page/Page column 33-34
(2008/12/05)
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