Comparison of Different Heterogeneous Catalysts for the Estolides Synthesis from Oleic Acid

2011 ◽  
Vol 364 ◽  
pp. 288-292 ◽  
Author(s):  
Nor Asikin Mohamad Nordin ◽  
Nadia Farhana Adnan ◽  
Noraini Hamzah ◽  
Wan Nor Roslam Wan Isahak ◽  
Alifee Ayatillah ◽  
...  
Keyword(s):  
Oleic Acid ◽  
Silica Gel ◽  
Perchloric Acid ◽  
Heterogeneous Catalysts ◽  
Addition Reaction ◽  
Xps Analysis ◽  
Reaction Products ◽  
Final Conversion ◽  
Direct Addition ◽  
Chromatographic Peaks

Different catalysts, namely various loading of perchloric acid on various supports; HClO4/silica (SiO2), HClO4/silica gel (SG) and HClO4/alumina (Al2O3) were tested for the direct addition reaction of oleic acid (OA) to form estolide compounds. The reactions were carried out under vacuum (2 mBar) for 10 hours at 70 °C under solvent-less conditions. LC-MS ToF of reaction products results showed chromatographic peaks for the presence of two new estolide compounds, oleic-oleic monoestolide acid (m/z563.51, as [M-H]-), and oleic-oleic diestolide acid (m/z845.77 [M-H]-). The optimum loading of HClO4for every support are 15 wt.% HClO4/SiO2(SiO215), 10 wt.% HClO4/SG (SG10) and 35 wt.% HClO4/Al2O3(Al2O335). The SG10 turned out to be the best catalyst, achieving a final conversion of 97.5 % with 79.8 % selectivity to oleic-oleic monoestolide acid and 17.7 % selectivity to oleic-oleic diestolide acid. The activity and selectivity of the SG10 have been investigated and compared with homogeneous HClO4. The optimum catalysts for every support were characterized by XPS analysis, BET, TEM and TPD-NH3.

Synthesis, Characterisation and Catalytic Activity of Sol-Gel Derived Silica-Mineral Acids

2012 ◽  
Vol 620 ◽  
pp. 278-283
Author(s):  
Nor Asikin Mohamad Nordin ◽  
Noraini Hamzah ◽  
Nadia Farhana Adnan ◽  
Wan Nor Roslam Wan Isahak ◽  
Mohd Zahid M. Yusof ◽  
...  
Keyword(s):  
Addition Reaction ◽  
Sol Gel ◽  
Mineral Acid ◽  
Liquid Chromatography Mass Spectrometry ◽  
Reaction Products ◽  
Mineral Acids ◽  
Gel Technique ◽  
Chromatographic Peaks ◽  
Silica Mineral ◽  
Efficient Heterogeneous Catalyst

Sol-gel silica-supported mineral acids (namely sol-gel perchloric acid (slg HClO4), sulfuric acid (slg H2SO4) and phosphoric acid (slg H3PO4), prepared by incorporating mineral acids molecules into silica via sol-gel technique, were used as an efficient heterogeneous catalyst for the direct addition reaction of oleic acid (OA) to form estolides compound. The reactions were carried out under vacuum (2 mBar) for 10 hours at 70°C under solvent-less conditions. Liquid chromatography-mass spectrometry time of flight (LC-MS ToF) of reaction products results showed chromatographic peaks for the presence of two new estolide compounds, oleic-oleic monoestolide acid (m/z 563.51, as [M--), and oleic-oleic diestolide acid (m/z 845.77 [M--). The HClO sol-gel catalyst turned out to be the best catalyst, achieving a final conversion of 76.4% with 83.4% selectivity to oleic-oleic monoestolide acid (OOM) and 16.6% selectivity to oleic-oleic diestolide acid (OOD). The activity and selectivity of the mineral acid sol-gel catalysts have been investigated and compared with homogeneous HClO4. The samples were characterised by XRD, TPD-NH3 and XPS.

scholarly journals Premium biofuels from straw – production of advanced biofuels using the Sylvan process

Paliva ◽  
2020 ◽  
pp. 87-92
Author(s):  
Jaroslav Aubrecht ◽  
David Kubička
Keyword(s):  
Heterogeneous Catalysts ◽  
Cetane Number ◽  
Reaction Products ◽  
Advanced Biofuels ◽  
Transportation Fuels ◽  
Noble Metal Catalysts ◽  
Eu Directive ◽  
Increasing Demand ◽  
High Yields ◽  
Middle Distillates

The increasing demand for transportation fuels, especially middle distillates, stimulates the research of new strategies to obtain or synthesize biofuels. The processing of lignocellulosic biomass (for example straw) is a process of great interest, because after its hydrolysis and subsequent dehydration of the resulting sugar monomers, very valuable substances including furfural are obtained. Then, furfural is selectively hydrogenated to 2-methylfuran, sylvan, that is the basic “building block” in the Sylvan process. This manuscript summarizes the knowledge on Sylvan process as a promising way of biofuels synthesis. By sylvan condensing with aldehydes, ketones or even 2-methylfuran itself, it is possible to prepare C13-C16 oxygenates in high yields up to 100 % under mild reaction conditions (30 - 60 °C) over various heterogeneous catalysts. Based on the overview, the heterogeneous catalysts are preferred and the immobilized sulfonic acids are the most active catalysts, however, expensive. The reaction products then may be hydrodeoxygenated commonly over supported noble metal catalysts to provide premium quality C13-C16 hydrocarbons to produce diesel or kerosene. These fractions have great low-temperature properties such as CFPP (-50 °C) or cetane number (70-72). According to the proposed sustainability prediction, this process could be sustainable in the Czech Republic, where 30 % of produced wheat straw could be used for the production of 130 kt advanced biofuels by Sylvan process required by EU directive RED II. Finally, the future approaches have been suggested.

scholarly journals Hydrosilylation of Reactive Quantum Dots and Siloxanes for Stable Quantum Dot Films

Polymers ◽  
2019 ◽  
Vol 11 (5) ◽  
pp. 905
Author(s):  
Changmin Lee ◽  
Eunhee Nam ◽  
Woosuk Lee ◽  
Heeyeop Chae
Keyword(s):  
Quantum Dots ◽  
Oleic Acid ◽  
Nucleophilic Addition ◽  
Addition Reaction ◽  
Light Emitting Diode ◽  
Molecular Structures ◽  
One Pot ◽  
Nucleophilic Addition Reaction ◽  
The Stability ◽  
Photo Stability

The reactive acrylate-terminated CdZnSeS/ZnS quantum dots (QDs) were designed and prepared by the effective synthetic route to bond with a siloxane matrix via hydrosilylation. The conventional QD with oleic acid ligands does not have any reactivity, so the QDs were functionalized to assign reactivity for the QDs by the ligand modification of two step reactions. The oleic acid of the QDs was exchanged for hydroxyl-terminated ligands as an intermediate product by one-pot reaction. The hydroxyl-terminated QDs and acrylate-containing isocyanates were combined by nucleophilic addition reaction with forming urethane bonds and terminal acrylate groups. No degradation in quantum yield was observed after ligand exchange, nor following the nucleophilic addition reaction. The modification reactions of ligands were quantitatively controlled and their molecular structures were precisely confirmed by FT-IR and 1H-NMR. The QDs with acrylate ligands were then reacted with hydride-terminated polydimethylsiloxane (H-PDMS) to form a QD-siloxane matrix by thermal curing via hydro-silylation for the first time. The covalent bonding between the QDs and the siloxane matrix led to improvements in the stability against oxygen and moisture. Stability at 85 °C and 85% relative humidity (RH) were both improved by 22% for the QD-connected siloxane QD films compared with the corresponding values for conventional QD-embedded poly(methylmethacrylate) (PMMA) films. The photo-stability of the QD film after 26 h under a blue light-emitting diode (LED) was also improved by 45% in comparison with those of conventional QD-embedded PMMA films.

Indoxyl Acetate Spray Reagent for Fluorogenic Detection of Cholinesterase Inhibitors in Environmental Samples

1969 ◽  
Vol 52 (1) ◽  
pp. 151-156
Author(s):  
R L Schutzmann ◽  
W F Barthel
Keyword(s):  
Thin Layer ◽  
Thin Layer Chromatography ◽  
Silica Gel ◽  
Environmental Samples ◽  
Cholinesterase Inhibitors ◽  
Opposite Polarity ◽  
Cholinesterase Inhibition ◽  
Solvent Mixtures ◽  
Reaction Products ◽  
Layer Chromatography

Abstract A cholinesterase inhibition method to detect ihionophosphates (P=S compounds) and their oxygen analogs (P=O) by twodimensional thin layer chromatography is described. Environmental samples are cleaned up on Florex columns and spotted on silica gel thin layer plates. Plates are developed in solvent mixtures of opposite polarity, then sprayed with an enzyme solution and indoxyl acetate. Submicrogram sensitivity is achieved by fluorogenic and chromogenic reaction. Some compounds give characteristic colored reaction products.

Perchloric Acid Adsorbed on Silica Gel: An Efficient Heterogeneous Reusable Catalyst for Synthesis of 1,5-Benzodiazepines.

ChemInform ◽  
2006 ◽  
Vol 37 (6) ◽  
Author(s):  
Biswanath Das ◽  
Majjigapu Ravinder Reddy ◽  
Ravirala Ramu ◽  
Kongara Ravinder Reddy ◽  
Madamanchi Geethangili
Keyword(s):  
Silica Gel ◽  
Perchloric Acid ◽  
Reusable Catalyst

Ionic Liquid [Bmim]OH Grafted Catalyst for Cycloaddition of Carbon Dioxide

2014 ◽  
Vol 989-994 ◽  
pp. 676-679 ◽  
Author(s):  
Xue Lan Zhang ◽  
Deng Feng Wang
Keyword(s):  
Carbon Dioxide ◽  
Ionic Liquid ◽  
Ionic Liquids ◽  
Silica Gel ◽  
Propylene Carbonate ◽  
Propylene Oxide ◽  
Heterogeneous Catalysts ◽  
Element Analysis ◽  
Mild Conditions ◽  
Adsorption Desorption

An ionic liquid 1-butyl-3-methylimidazolium hydroxide ([Bmim]OH) was grafted on silica gel by post-grafting method. Such grafted ionic liquids (GILs) which were verified by means of FTIR, element analysis N2adsorption-desorption and TG could be used as highly effective heterogeneous catalysts toward propylene carbonate synthesis through cycloaddition of carbon dioxide with propylene oxide under solventless and mild conditions.

Supported Heteropolyacids as Heterogeneous Catalysts for Propene Metathesis

1995 ◽  
Vol 60 (3) ◽  
pp. 443-450 ◽  
Author(s):  
Pavol Hudec ◽  
Katarina Prandová
Keyword(s):  
Surface Properties ◽  
Silica Gel ◽  
Heterogeneous Catalysts ◽  
Keggin Type

Catalysts containing tungsten or molybdenum in the form of Keggin type heteropolyacids, like H3PW12O40, H4SiW12O40 and H3PMo12O40, supported on silica gel were prepared. The acid and surface properties of heteropolyacids and their supported forms are discussed. Keggin type heteropolyacids supported on silica gel have been found active for propene metathesis, the activity was compared with those of the classical catalyst WO3/SiO2. The highest activity and selectivity for studied reaction showed catalyst prepared on the base of H3PW12O40.

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