1115-01-1Relevant academic research and scientific papers
Metal oxide-triazole hybrids as heterogeneous or reaction-induced self-separating catalysts
Amarante, Tatiana R.,Neves, Patrícia,Valente, Anabela A.,Paz, Filipe A. Almeida,Pillinger, Martyn,Gon?alves, Isabel S.
, p. 354 - 367 (2016)
The hybrid metal oxide-triazole materials [MoO3(trz)0.5] (1) and [W2O6(trz)] (2) (trz?=?1,2,4-triazole) have been hydrothermally synthesized and characterized by different techniques (TGA, SEM, 1H and 13C MAS NMR, FT-IR spectroscopy, and structure determination by Rietveld analysis of high resolution synchrotron powder XRD data). Materials 1 and 2 display distinct behaviors when applied as catalysts for oxidation reactions with alcohol, aldehyde, olefin and sulfide substrates, and are more effective with hydrogen peroxide as the oxidant than with tert-butylhydroperoxide. The MoVI hybrid 1 transforms into soluble active species during cis-cyclooctene epoxidation with H2O2. When consumption of H2O2 reaches completion, spontaneous reassembly of the 2-dimensional molybdenum oxide network of 1 takes place and the hybrid precipitates as a microcrystalline solid that can be easily separated and recycled. Reaction-induced self-separation behavior occurs with 1, H2O2 and other substrates such as methyl oleate and methylphenylsulfide. The WVI hybrid 2 behaves differently, preserving its structural features throughout the heterogeneous catalytic process.
Plasticizer and surfactant formation from food-waste- and algal biomass-derived lipids
Pleissner, Daniel,Lau, Kin Yan,Zhang, Chengwu,Lin, Carol Sze Ki
, p. 1686 - 1691 (2015)
The potential of lipids derived from food-waste and algal biomass (produced from food-waste hydrolysate) for the formation of plasticizers and surfactants is investigated herein. Plasticizers were formed by epoxidation of double bonds of methylated unsaturated fatty acids with in situ generated peroxoformic acid. Assuming that all unsaturated fatty acids are convertible, 0.35 and 0.40 g of plasticizer can be obtained from 1 g of crude algae- or food-waste-derived lipids, respectively. Surfactants were formed by transesterification of saturated and epoxidized fatty acid methyl esters (FAMEs) with polyglycerol. The addition of polyglycerol would result in a complete conversion of saturated and epoxidized FAMEs to fatty acid polyglycerol esters. This study successfully demonstrates the conversion of food-waste into value-added chemicals using simple and conventional chemical reactions.
Biobased Aldehydes from Fatty Epoxides through Thermal Cleavage of β-Hydroxy Hydroperoxides**
De Dios Miguel, Thomas,Duc Vu, Nam,Lemaire, Marc,Duguet, Nicolas
, p. 379 - 386 (2021)
The ring-opening of epoxidized methyl oleate by aqueous H2O2 has been studied using tungsten and molybdenum catalysts to form the corresponding fatty β-hydroxy hydroperoxides. It was found that tungstic acid and phosphotungstic acid gave the highest selectivities (92–93 %) towards the formation of the desired products, thus limiting the formation of the corresponding fatty 1,2-diols. The optimized conditions were applied to a range of fatty epoxides to give the corresponding fatty β-hydroxy hydroperoxides with 30–80 % isolated yields (8 examples). These species were fully characterized by 1H and 13C NMR spectroscopy and HPLC-HRMS, and their stability was studied by differential scanning calorimetry. The thermal cleavage of the β-hydroxy hydroperoxide derived from methyl oleate was studied both in batch and flow conditions. It was found that the thermal cleavage in flow conditions gave the highest selectivity towards the formation of aldehydes with limited amounts of byproducts. The aldehydes were both formed with 68 % GC yield, and nonanal and methyl 9-oxononanoate were isolated with 57 and 55 % yield, respectively. Advantageously, the overall process does not require large excess of H2O2 and only generates water as a byproduct.
Hyperbranched polyesters by polycondensation of fatty acid-based AB: N-type monomers
Testud, Blandine,Pintori, Didier,Grau, Etienne,Taton, Daniel,Cramail, Henri
, p. 259 - 269 (2017)
Widely available vegetable oils were readily derivatized into chemically pure ABn-type monomers (n = 2 or 3). Their polymerization led to unprecedented hyperbranched polyesters. Four different AB2/AB3-type monomers bearing one A-type methyl ester and two or three B-type alcohol functions were purposely synthesized via two elementary steps, i.e. epoxidation of the internal double bond of the vegetable oil precursors followed by ring-opening of the epoxy groups under acidic conditions. The polycondensation of these bio-sourced monomers was performed in bulk, in the presence of an appropriate catalyst, giving access to modular hyperbranched polyesters with tunable properties. Among the catalysts tested, zinc acetate, 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD) and sodium methoxide proved the most effective, allowing the achievement of molar masses in the range 3000-10000 g mol-1 and dispersities varying from 2 to 15, depending on the initial conditions. The degree of branching, DB, as determined by 1H NMR spectroscopy, was found to be between 0.07 and 0.45. The as-devised hyperbranched polyesters displayed either amorphous or semi-crystalline properties, as a function of the selected AB2/AB3-type initial monomers, with a glass transition temperature, Tg, ranging from -33 to 9 °C and a decomposition temperature at 5 wt% of the sample, Td5%, varying from 204 to 340 °C.
Mild catalytic oxidations of unsaturated fatty acid methyl esters (FAMEs) by oxovanadium complexes
Cecchini, Martina Maya,De Angelis, Francesco,Iacobucci, Claudio,Reale, Samantha,Crucianelli, Marcello
, p. 120 - 128 (2016)
A selection of unsaturated fatty acid methyl esters, namely methyl oleate (C18:1), methyl linoleate (C18:2) and methyl linolenate (C18:3) has been oxidized under mild homogeneous catalytic conditions, using a series of oxovanadium(IV) complexes containing 4-acyl-5-pyrazolone donor ligands with different substituents on acyl residue. The main goal was to evaluate the catalytic role exerted by oxovanadium(IV) metal center, as precursor complex, in the selective oxyfunctionalization of carbon-carbon double bonds of these bio-renewable resources, as a greener alternative to more drastic processes currently used at the industrial level. The three substrates, oxidized using tert-butylhydroperoxide as main oxidant, with or without solvents, showed high conversions of starting materials and high selectivities in the formation of corresponding mono- di- and tri-epoxides, especially under solvent-less conditions. Investigations on a probable catalytic cycle mechanism operative in the tert-butylhydroperoxide oxidation of a simple FAME model substrate, have been performed by means of ESI-MS.
Fe(6-Me-PyTACN)-catalyzed, one-pot oxidative cleavage of methyl oleate and oleic acid into carboxylic acids with H2O2 and NaIO 4
Spannring, Peter,Prat, Irene,Costas, Miquel,Lutz, Martin,Bruijnincx, Pieter C. A.,Weckhuysen, Bert. M.,Klein Gebbink, Robertus J. M.
, p. 708 - 716 (2014)
The first Fe-based catalytic system for the oxidative cleavage of unsaturated fatty acids and esters to carboxylic acids is reported. The system comprises [Fe(OTf)2(6-Me-PyTACN)] (2) (6-Me-PyTACN = 1-[(6-methyl-2-pyridyl)methyl]-4,7-dimethyl-1,4,7-triazacyclononane, OTf = trifluoromethane sulfonate anion) as the catalyst (3 mol%) either with a combination of hydrogen peroxide and NaIO4 or exclusively with NaIO4 as the oxidant, and operates at 0 °C or ambient temperature. Under these standard conditions (method A), methyl oleate is converted in a one-pot procedure into 50-55% of both nonanoic and azelaic acid, together with some epoxide and aldehyde intermediates as byproducts. These yields can be further improved by addition of sulfuric acid (method B) to hydrolyze the epoxide byproducts, by including a pH neutralization step and addition of more catalyst (1 mol%). Under the optimized conditions, both methyl oleate and oleic acid are converted into high yields of the corresponding carboxylic acids (80-85%). Overall, this catalytic system provides an alternative to the industrial ozonolysis of oleic acid and to catalytic Ru- and Os-based systems for the oxidative cleavage of unsaturated fatty acids and esters.
Amphiphilic dipyridinium-phosphotungstate as an efficient and recyclable catalyst for triphasic fatty ester epoxidation and oxidative cleavage with hydrogen peroxide
De La Garza, Luis Carlos,De Oliveira Vigier, Karine,Chatel, Gregory,Moores, Audrey
, p. 2855 - 2862 (2017)
A novel amphiphilic dipyridinium peroxophosphotungstate ion pair was developed as a selective and recyclable catalyst for the triphasic epoxidation of fatty acids and esters with hydrogen peroxide. The synthesis of the catalyst was studied extensively by solid and liquid phase 31P nuclear magnetic resonance (NMR). The oxidation of vegetable oils is of prime importance for the production of lubricants, plasticizers, polymer stabilizers and other olefinic compounds. Based on the oxidizing activity of peroxophosphotungstates, we designed a lipophilic phase transfer agent that renders the active complex insoluble in the reaction media, without having to support it on a matrix. This affords a catalyst combining the activity of homogeneous catalysts and the recyclability of heterogeneous systems. We show that this catalyst is able to fully epoxidize methyl oleate with excellent selectivity, with a turnover frequency of 149 at 60 °C, and can be easily recycled, to reach a record turn over number of 1868. A larger scale experiment on 13 grams and a scope including linoleic and ricinoleic acids were also demonstrated. The catalyst also shows excellent activity and selectivity for the oxidative cleavage of methyl oleate and the oxidation of small olefins.
Valorization of Methyl Azelaaldehydate – A Vegetable Oil Based Platform Molecule for the Synthesis of Monomers through Stetter Reaction
Charvieux, Aubin,Duc Vu, Nam,Duguet, Nicolas,Lemaire, Marc
, p. 1251 - 1256 (2019)
The valorization of vegetable oil-derived methyl azelaaldehydate (methyl 9-oxo-nonanoate) to monomers was studied through NHC-catalysed Stetter reaction. Among the Michael acceptors tested, dimethyl fumarate gave the highest selectivity (97 %) for the corresponding Stetter adduct, thus limiting the competing benzoin condensation.
Selective dihydroxylation of methyl oleate to methyl-9,10-dihydroxystearate in the presence of a recyclable tungsten based catalyst and hydrogen peroxide
Araji, Nahla,Chatel, Gregory,Moores, Audrey,Jér?me, Fran?ois,De Oliveira Vigier, Karine
, p. 11507 - 11512 (2020)
The dihydroxylation of fatty methyl esters is of prime importance for the synthesis of surfactants and lubricants. The conversion of methyl oleate (MO) to 98percent yield of methyl-9,10-dihydroxystearate (MDHS) was performed in the presence of H2O2 and H3PW12O40 catalyst in the absence of a phase transfer agent. The study of the effect of hydrogen peroxide concentration revealed that significant catalytic activity was only achieved for an optimal amount of H2O2. A mechanism for this reaction was proposed where hydrogen peroxide reacts with H3PW12O40 to produce peroxo-phosphotungstate anions, which directly dihydroxylate MO. The recyclability of the catalyst was also studied. To this aim, a recyclable form of the heteropolyacid was synthesized using Cs cations (Cs2.3H0.7PW12O40). This catalyst was recycled up to three cycles without significant loss in catalytic performances. This journal is
Synthesis and biological properties of some novel heterocyclic homoprostanoids
Bender,Berkoff,Groves,Sofranko,Wellman,Liu,Begosh,Horodniak
, p. 1094 - 1098 (1975)
In the search for prostaglandin like structures capable of exerting specific and desirable biological properties, a variety of simple heterocyclic homoprostanoidal derivatives was synthesized from readily available stearic acid derivatives Compounds 5b and 5e were found to be more than 100 times as potent as PGE1 and PGE2 in a tracheal chain bioassay and, like 6, 9, and 12, inhibited PGE2 induced diarrhea. Derivatives 6 and 7a showed significant PG synthetase inhibitor activity.
