13481-97-5Relevant articles and documents
Integrated extraction and catalytic upgrading of microalgae lipids in supercritical carbon dioxide
Zimmerer, Julia,Pingen, Dennis,Hess, Sandra K.,Koengeter, Tobias,Mecking, Stefan
, p. 2428 - 2435 (2019)
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.
Re2O7/SiO2*Al2O3-SnR4 or -PbR4, a Highly Active Catalyst for the Metathesis of Functionalized Alkenes
Xiaoding, Xu,Mol, J. C.
, p. 631 - 633 (1985)
Low-rhenium-loading Re2O7/SiO2*Al2O3-SnR4 or -PbR4 (R = alkyl) catalysts show high activity for the metathesis of functionalized alkenes at 293 +/- 2 K, which is attributed to their high Broensted acidity.
Fast-initiating, ruthenium-based catalysts for improved activity in highly E-selective cross metathesis
Ahmed, Tonia S.,Grubbs, Robert H.
, p. 1532 - 1537 (2017)
Ruthenium-based olefin metathesis catalysts bearing dithiolate ligands have been recently employed to generate olefins with high E-selectivity (>99% E) but have been limited by low to moderate yields. In this report, 1H NMR studies reveal that a major contributing factor to this low activity is the extremely low initiation rates of these catalysts with trans olefins. Introducing a 2-isopropoxy-3-phenylbenzylidene ligand in place of the conventional 2-isopropoxybenzylidene ligand resulted in catalysts that initiate rapidly under reaction conditions. As a result, reactions were completed in significantly less time and delivered higher yields than those in previous reports while maintaining high stereoselectivity (>99% E).
A Synthesis of (Z)-Octadec-9-enedioic Acid
Brunow, Goesta,Stick, Robert V.,Syrjaenen, Kaisa,Tilbrook, D. Matthew G.,Williams, Spencer J.
, p. 1893 - 1898 (1995)
The monomethyl ester of azelaic acid was transformed into two fragments, namely triphenylphosphonium bromide and methyl 9-oxononanoate.A Wittig reaction between these two fragments produced dimethyl (Z)-octadec-9-enedioate and subsequent hydrolysis gave the title diacid.Interestingly, the same acid was available directly from oleic acid in a published procedure which utilized a mutant strain of Candida tropicalis.
Remarkably Efficient Microwave-Assisted Cross-Metathesis of Lipids under Solvent-Free Conditions
Ullah, Aman,Arshad, Muhammad
, p. 2167 - 2174 (2017)
Catalytic transformation of renewable feedstocks into fine chemicals is in high demands and olefin metathesis is a sophisticated tool for biomass conversion. Nevertheless, the large-scale viability of such processes depends on the conversion efficiency, energy efficiency, catalytic activity, selective conversion into desired products, and environmental footprint of the process. Therefore, conversions of renewables by using simple, swift, and efficient methods are desirable. A microwave-assisted ethenolysis and alkenolysis (using 1,5-hexadiene) of canola oil and methyl esters derived from canola oil (COME) and waste/recycled cooking oil (WOME) was carried out by using ruthenium-based catalytic systems. A systematic study using 1st and 2nd generation Grubbs and Hoveyda–Grubbs catalysts was carried out. Among all ruthenium catalysts, 2nd generation Hoveyda–Grubbs catalyst was found to be highly active in the range of 0.002–0.1 mol % loading. The conversions proved to be rapid providing unprecedented turnover frequencies (TOFs). High TOFs were achieved for ethenolysis of COME (21 450 min?1), direct ethenolysis of canola oil (19 110 min?1), for WOME (15 840 min?1) and for cross-metathesis of 1,5-hexadiene with COME (10 920 min?1). The ethenolysis of commercial methyl oleate was also performed with a TOF of 8000 min?1 under microwave conditions.
Synthesis and Activity of Six-Membered Cyclic Alkyl Amino Carbene-Ruthenium Olefin Metathesis Catalysts
Grubbs, Robert H.,Samkian, Adrian E.,Virgil, Scott C.,Xu, Yan,Yoon, Ki-Young
, (2020)
Ru-cyclic alkyl amino carbene (Ru-CAAC) olefin metathesis catalysts perform extraordinarily in metathesis macrocyclization and ethenolysis, but previous studies have been limited to the use of five-membered CAAC (CAAC-5) ligands. In this work, we synthesized a different group of ruthenium catalysts with more σ-donating and π-accepting six-membered CAAC (CAAC-6) ligands, and their metathesis activity was probed through initiation studies, ring-closing metathesis (RCM), cross-metathesis, and ethenolysis. These catalysts display higher initiation rates than analogous Ru-CAAC-5 complexes but demonstrate lower activity in RCM and ethenolysis.
HETEROGENEOUS METATHESIS OF UNSATURATED ESTERS USING A RHENIUM-BASED CATALYST
Bosma, R.H.A.,Aardweg, G.C.N. Van Den,Mol, J.C.
, p. 159 - 172 (1983)
The heterogeneous metathesis of unsaturated esters was carried out at room temperature, using the catalyst system Re2O7/Al2O3 with an organometallic compound as cocatalyst.The influence of several parameters on the activity of the catalyst was studied with methyl oleate (methyl-Z-9-octadecenoate) as substrate.The use of a nonpolar solvent and a cocatalyst of general formula SnR4, in which R is a linear alkyl group, provided optimal reaction conditions.The activity of a deactivated catalyst could be completely restored by recalcination in oxygen, followed by addition of a further amount of cocatalyst.The reactivities of various unsaturated esters as a function of their molecular structure was studied; these esters undergo metathesis when the double bond and the carboxylic group are separated by at least one methylene group.In general, α,β-unsaturated esters show a reasonable activity for cometathesis with simple alkenes, such as E-3-hexene.
Cis-Dichloro Sulfoxide Ligated Ruthenium Metathesis Precatalysts
Johns, Adam M.,Fiamengo, Bryan A.,Herron, Jessica R.,Bourg, Jean-Baptiste,Doppiu, Angelino,Karch, Ralf,Pederson, Richard L.
, p. 218 - 222 (2019)
Novel sulfoxide-ligated ruthenium complexes were prepared by reacting second-generation metathesis precatalysts with p-toluenesulfonyl chloride in the presence of a small excess of sulfoxide. (SIMes)Ru(S-DMSO)(Ind)Cl2 (M54) and (SIMes)Ru(S-DMSO)(CHPh)Cl2 (M54a) were characterized crystallographically and, in agreement with NMR spectroscopy, were found to adopt an unusual cis-dichloro configuration. Despite having traditionally latent geometry, the new complexes were found to be highly reactive precatalysts for routine metathesis transformations. Additionally, the robustness, scalability, and industrial utility of M54 as a ruthenium synthon are demonstrated.
A novel ruthenium carbene dimer that is active in the metathesis of internal alkenes; The crystal structure of Ru2(=CHPh)2(CF3CO2) 2(μ-CF3CO2)2(PCy 3)2(μ-H2O)
Buchowicz,Mol,Lutz,Spek
, p. 205 - 210 (1999)
The reaction of Ru(=CHPh)Cl2(PCy3)2 (1) with two equivalents of CF3CO2Ag gives Ru2(=CHPh)2(CF3CO2) 2(μ-CF3CO2)2(PCy 3)2(μ-H2O) (2) in high yield. The crystal structure of 2 reveals that the ruthenium atoms are bridged by two trifluoroacetate groups and one water molecule, and that the ruthenium coordination is distorted octahedral. Complex 2 is active in the metathesis of internal alkenes.
Self-metathesis of methyl oleate on silica-supported Hoveyda-Grubbs catalysts
Zelin, Juan,Trasarti, Andrés F.,Apesteguía, Carlos R.
, p. 84 - 88 (2013)
The self-metathesis of methyl oleate (MO) to yield 9-octadecene and 9-octadecene-1,18-dioate (9-OD) was studied in liquid-phase on silica-supported Hoveyda-Grubbs complex catalysts (HG/SiO2) containing 0.43-6.0 wt.% HG. The reaction was carried out in a batch reactor at 303-343 K and 101.3 kPa, using cyclohexane as solvent. HG/SiO2 catalysts were active and highly selective for the MO metathesis reaction; equilibrium values of MO conversion and 9-OD yield were reached in 80 min. No catalyst leaching took place in cyclohexane. Catalysts containing HG > 0.87 wt.% showed no significant deactivation after two consecutive catalytic tests.
