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.
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).
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.
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.
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.
Novel ruthenium(II)2 carboxylates as catalysts for alkene metathesis
Buchowicz, Wlodzimierz,Ingold, Florent,Mol, Johannes C.,Lutz, Martin,Spek, Anthony L.
, p. 2842 - 2847 (2001)
The reactions of [Ru(=CHR)Cl2(PCy3)2] (1: R = Ph; 1a: R = -CH=CPh2) with silver salts of carboxylic acids afforded new dimeric complexes of the general formula [Ru2(=CHR)2(R′CO2)2 (μ-R′CO2)2(PCy3)2 (-H2O)] (2: R = Ph, R′ = CF3; 3: R = Ph, R′ = C2F5; 4: R = -CH=CPh2, R′ = CF3; 5: R = Ph, R′ = C6F5; 6: R = -CH=CPh2, R′ = C6F5; 7: R = -CH=CPh2, R′ = CCl3) in good yields. With R′ = CF3, C2F5 or CCl3 these complexes are active catalysts for metathesis of acyclic alkenes, including unsaturated fatty acid esters, as well as for ring closing metathesis. The reactivity of these complexes with bases and weak donor solvents has been studied and their half-life times in several media were determined.
Mixed-oxide Catalysts for the Metathesis of Functionalized Alkenes
Xiaoding, Xu,Imhoff, Pieter,Aardweg, Godefridus C. N. van den,Mol, J. C.
, p. 273 - 275 (1985)
Low-rhenium-loading Re2O7/Al2O3-MR4 (M = Sn or Pb; R = Me, Et, or Bu) catalysts show good activity at room temperature (293 +/- 2 K) for the metathesis of functionalized alkenes, such as unsaturated esters, when they are modified with MoO3, V2O5, or WO3.
Bis(Cyclic Alkyl Amino Carbene) Ruthenium Complexes: A Versatile, Highly Efficient Tool for Olefin Metathesis
Gawin, Rafa?,Kozakiewicz, Anna,Guńka, Piotr A.,D?browski, Pawe?,Skowerski, Krzysztof
, p. 981 - 986 (2017)
The state-of-the-art in olefin metathesis is application of N-heterocyclic carbene (NHC)-containing ruthenium alkylidenes for the formation of internal C=C bonds and of cyclic alkyl amino carbene (CAAC)-containing ruthenium benzylidenes in the production of terminal olefins. A straightforward synthesis of bis(CAAC)Ru indenylidene complexes, which are highly effective in the formation of both terminal and internal C=C bonds at loadings as low as 1 ppm, is now reported.
Rossi
, p. 817,832 (1977)
Supported Ru olefin metathesis catalysts: Via a thiolate tether
Renom-Carrasco, Marc,Mania, Philipp,Sayah, Reine,Veyre, Laurent,Occhipinti, Giovanni,Gajan, David,Lesage, Anne,Jensen, Vidar R.,Thieuleux, Chloé
, p. 2886 - 2890 (2019)
Thiolate-coordinated ruthenium alkylidene complexes can give high Z-selectivity and stereoretentivity in olefin metathesis. To investigate their applicability as heterogeneous catalysts, we have successfully developed a methodology to easily immobilize prototype ruthenium alkylidenes onto hybrid mesostructured silica via a thiolate tether. In contrast, the preparation of the corresponding molecular complexes appeared very challenging in solution. These prototype supported complexes contain small thiolates but still, they are slightly more Z-selective than their molecular analogues. These results open the door to more active and selective heterogeneous catalysts by supporting more advanced thiolate Ru-complexes.
In Situ Generation of Ru-Based Metathesis Catalyst. A Systematic Study
Müller, Daniel S.,Raoul, Yann,Le N?tre, Jér?me,Baslé, Olivier,Mauduit, Marc
, p. 3511 - 3518 (2019)
A systematic study for the in situ generation of Ru-based metathesis catalysts was described. Assembly of commercially available and inexpensive reagents [Ru(p-cymene)Cl2]2, SIPr·HCl, and n-BuLi led to the formation of 18 electron arene-ruthenium complexes that, in the presence of additives such as alkynes, cyclopropenes, and diazoesters, generated highly selective and efficient catalytic systems applicable to a variety of olefin metathesis transformations. Notably, we were able to achieve a productive TON of 4500 for the self-metathesis of methyl oleate, a reaction which could be easily upscaled to 2 kg.
Low pressure ethenolysis of renewable methyl oleate in a microchemical system
Park, Chan Pil,Van Wingerden, Matthew M.,Han, So-Yeop,Kim, Dong-Pyo,Grubbs, Robert H.
, p. 2398 - 2401 (2011)
Chemical equations presented. A microchemical system for ethenolysis of renewable methyl oleate was developed, in which the dual-phase, microfluidic design enabled efficient diffusion of ethylene gas into liquid methyl oleate through an increased contact area. The increased mass transfer of ethylene favored the formation of desired commodity chemicals with significantly suppressed homometathesis when compared to the bulk system. In addition to higher selectivity and conversion, this system also provides the typical advantages of a microchemical system, including the possibility of convenient scale-up.
One-pot direct synthesis route to self-assembled highly ordered Zn-decorated mesoporous aluminium oxide toward efficient and sustainable metathesis heterogeneous catalyst design
Abidli, Abdelnasser
, p. 92743 - 92756 (2015)
Hexagonally well-organized ZnCl2-OMA materials have been successfully synthesized by a one-pot approach using a sol-gel method at ambient temperature and pressure. These materials were prepared through simultaneous self-assembly process with F127 as directing agent combined with in situ impregnation of ZnCl2. The new approach was found to be compatible with various common aluminium precursors and carboxylic acids used as self-assembly interfacial protectors. The obtained ZnCl2-OMA materials were fully characterized using XRD, N2 adsorption-desorption, TEM, SEM, EDX, XPS and 1H and 27Al MAS-NMR techniques. These materials were compared with the zinc chloride-doped organized mesoporous alumina (ZnCl2-OMA) supports prepared through a conventional two steps process that includes OMA synthesis and then post-synthesis incorporation of ZnCl2. Thus, the one-pot synthesized materials were found to exhibit improved properties compared to the conventional ones, particularly larger BET surface area. The synthesized ZnCl2-OMA materials were then used as catalytic supports for methyltrioxorhenium (MTO), showing enhanced catalytic performance for methyl oleate self-metathesis, demonstrating better activity and selectivity towards desired metathesis products. These features are highly beneficial for large-scale materials synthesis through fast, simple, easy and low-cost introduction of functionalities on mesoporous materials surface without multi-step procedures.
ACYCLIC CARBENE LIGAND FOR RUTHENIUM COMPLEX FORMATION, RUTHENIUM COMPLEX CATALYST, AND USE THEREOF
-
Paragraph 0124-0130, (2021/05/14)
Provided are a novel acyclic carbene ligand for ruthenium complex formation; a ruthenium complex catalyst using the ligand; a method of using the complex as a catalyst in an ethylene-metathesis ethenolysis reaction; a method of preparing the ruthenium complex catalyst; and a method of preparing a linear alpha-olefin, the method including the step of reacting a linear or cyclic alkene compound in the presence of the ruthenium complex catalyst. The acyclic carbene ligand of the present invention and the ruthenium complex catalyst using the same have high selectivity and turnover number for terminal olefin formation in an ethylene-metathesis ethenolysis reaction, and thus linear α-olefins may be prepared with a high yield.
Preparation method of octadecanedioic acid (by machine translation)
-
Paragraph 0030-0035; 0043-0048; 0056-0061, (2020/07/12)
The method has the advantages that raw materials are cheap and easily available, and 9 - McMMMMMurry Coupling forms a coupling intermediate; and then, the method is cheap and easily available in raw materials, simple in post-treatment steps, and capable of greatly reducing production cost and selling price of octadecanedioic acid. (by machine translation)
Cysteine-Targeted Insecticides against A. gambiae Acetylcholinesterase Are Neither Selective nor Reversible Inhibitors
Gorecki, Lukas,Andrys, Rudolf,Schmidt, Monika,Kucera, Tomas,Psotka, Miroslav,Svobodova, Barbora,Hrabcova, Veronika,Hepnarova, Vendula,Bzonek, Petr,Jun, Daniel,Kuca, Kamil,Korabecny, Jan,Musilek, Kamil
, p. 65 - 71 (2019/12/25)
Acetylcholinesterase cysteine-targeted insecticides against malaria vector Anopheles gambia and other mosquitos have already been introduced. We have applied the olefin metathesis for the preparation of cysteine-targeted insecticides in high yields. The prepared compounds with either a succinimide or maleimide moiety were evaluated on Anopheles gambiae and human acetylcholinesterase with relatively high irreversible inhibition of both enzymes but poor selectivity. The concept of cysteine binding was not proved by several methods, and poor stability was observed of the chosen most potent/selective compounds in a water/buffer environment. Thus, our findings do not support the proposed concept of cysteine-targeted selective insecticides for the prepared series of succinimide or maleimide compounds.
