Reusable Solid Catalyst Research Articles

Cascade Utilization of Biomass: Strategy for Conversion of Cellulose, Hemicellulose, and Lignin into Useful Chemicals

Efficient utilization of all three components of lignocellulose—cellulose, hemicellulose, and lignin—impels efficient utilization of carbon dioxide fixed by photosynthesis. Conversion of all three of these polymeric components of lignocellulosic biomass into the corresponding monomeric chemicals was investigated using reusable solid catalysts in water without organic solvents, acids, or bases. Cellulose and hemicellulose were first converted into sugar alcohols such as sorbitol and xylitol using a carbon-supported platinum catalyst (Pt/C), H2, and bagasse as a reactant at 463 K for 16 h. The sugar alcohol yield was 64%. The solid residue from this process, which was mainly lignin and Pt/C, was recovered by simple filtration. Lignin in the solid residue was then converted into aromatic products at 673 K for 1 h. The yield of monomeric aromatics was 40%. After this process, only Pt/C catalyst was recovered as a solid residue, and it retained its activity for the conversion of all three components of lignoce...

5-Na/ZnO doped mesoporous silica as reusable solid catalyst for biodiesel production via transesterification of virgin cottonseed oil

Abstract 5-Na/ZnO loaded SBA-15 has been prepared by one-pot method in atmospheric conditions (without employing hydrothermal treatment) and following wet impregnation method. The prepared catalyst was characterised by using several techniques viz., BET method for determination of surface area, FE-SEM for morphology of catalyst, XPS study to determine the oxidation state of constituent elements. The catalyst was utilised for transesterification from virgin cotton seed oil and the catalyst activity was dependant on its basic strength. Under optimal reaction conditions of catalyst amount 12 wt%, methanol to oil molar ratio of 24:1 at reaction temperature of 65 °C, the prepared catalyst yielded > 98% fatty acid methyl ester in 4 h of reaction duration. The catalyst was able to yield conversion level as good as ∼74% even in 5th cycle after regeneration. Leaching of

Solid Catalyst Nanoparticles derived from Oil-Palm Empty Fruit Bunches (OP-EFB) as a Renewable Catalyst for Biodiesel Production

Solid nanocatalyst derived from oil-palm empty fruit bunches (OP-EFB) fiber was successfully synthesized and its application for biodiesel production was investigated. The OPEFB was treated by burning, milling and heating methods to generate ashes in a nanoparticle size. The nanoparticle palm-bunch ash was characterized by scanning electron microscopy (SEM) and x-ray diffraction (XRD). The effects of the calcination temperature and catalyst amounts for transesterification reactions were investigated. XRD analysis of palm bunch ash exhibited that the highest composition of peaks characteristic were potassium oxide (K2O). SEM analysis showed that the nano palm bunch ash have a particle size ranging of 150-400 nm. The highest conversion of palm-oil to biodiesel reach to 97.90% was observed by using of palm bunch ash nanocatalyst which heated at 600°C, 3 h reaction time and 1% catalyst amount. Reusability of palm bunch ash catalysts was also examined. It was found that of its high active sites, reusable solid catalyst was obtained by just heating of palm bunch ash. It has a capability to reduce not only the amount of catalyst consumption but also reduce the reaction time of transesterification process.

Supported Porous Nanomaterials as Efficient Heterogeneous Catalysts for CO2 Fixation Reactions.

CO2 is a major greenhouse gas responsible for global warming and can act as an abundant and inexpensive C1 source for enhancing the chain length/functionalization of a wide range of reactive organic molecules. It is moderately reactive, nontoxic and renewable. Thus, CO2 fixation reactions are important to meet the global challenges, that is, to mitigate the concentration of CO2 in the atmosphere through its fruitful utilization, which is of great interest from economic and environmental perspectives. Various metallic nanoparticles as well as metal oxides can be supported over high surface area porous materials and the resulting nanomaterial can act as heterogeneous and reusable solid catalyst for CO2 fixation reactions for the synthesis of a large number of fuels, natural products agrochemicals, and pharmaceutical compounds. Here we present an overview of the recent progress as well as promising future of metal/metal oxide nanoparticles supported over porous nanomaterials as heterogeneous catalysts for a wide spectrum of these CO2 fixation reactions.

One‐pot, Multi‐Component Synthesis of Novel Bis‐Spiro Pyranopyrazole Derivatives in the Presence of DABCO as an Efficient and Reusable Solid Base Catalyst

AbstractA simple and elegant synthesis of some novel bis‐spiro pyranopyrazoles has been achieved via the condensation reaction between bis‐isatins, malononitrile, hydrazine hydrate and ß‐ketoester derivatives in the presence of a catalytic amount of 1, 4‐diazabicyclo [2.2.2] octane (DABCO) in ethanol at reflux conditions. The significant features of the present method are structure diversity, product complexity, procedure and work‐up simplicity, environmentally friendly, good to excellent yields and catalyst recyclability.

Tandem oxidative isocyanide-based cycloaddition reactions in the presence of MIL-101(Cr) as a reusable solid catalyst

The tandem oxidative three-component synthesis of two types of the heterocycles such as furans and imidazopyridines, via isocyanides [1+4] cycloaddition reactions in the presence of MIL-101(Cr) under aerobic conditions are reported. When the 4-toluenesulfonylmethyl isocyanide was used, an unexpected [3+2] cycloaddition reaction of isocyanides with aldehydes accomplished and dihydrophenyloxazoles and phenyloxazoles produced. These syntheses were successfully carried out using a wide scope of the substrates.

Spirooxindole-fused pyrazolo pyridine derivatives: NiO–SiO2 catalyzed one-pot synthesis and antimicrobial activities

ABSTRACTWe describe here a one-pot synthesis of 13 spirooxindole-fused pyrazolo pyridine derivatives using NiO–SiO2 catalyst via three-component reaction of isatin, 5-amino-3-methylpyrazole, and malononitrile. This multicomponent one-pot protocol also features shorter reaction time, good yield, and simple work-up using a recoverable and reusable solid acid heterogeneous catalyst. The NiO–SiO2 catalyst was characterized using different instrumental techniques such as X-ray diffraction study, surface area analysis, transmission electron microscopy, scanning electron microscopy, X-ray photoelectron spectroscopy, UV-DRS (diffuse reflectance spectroscopy), and energy dispersive X-ray analysis (EDX). The new compounds were tested for in-vitro anti-microbial activity.

Quantitative synthesis of 2,5-bis(hydroxymethyl)furan from biomass-derived 5-hydroxymethylfurfural and sugars over reusable solid catalysts at low temperatures

Quantitative production of 2,5-bis(hydroxymethyl)furan (BHMF) was achieved at room temperature (25 °C) via highly selective hydrogenation of biomass-derived 5-hydroxymethylfurfural (HMF) employing alkali salt KF as catalyst and polymethylhydrosiloxane (PMHS) as hydrogen source. A moderate turnover frequency (TOF: 4.2 h−1) was observed for this mild and sustainable reaction process. Moreover, a combination of Amberlyst-15 with KF could successfully catalyze the direct synthesis of BHMF from hexose sugars such as fructose and inulin via tandem dehydration and hydrogenation in a single pot. This catalytic system is more selective compared with H2-participated counterpart, giving a high BHMF yield and selectivity of up to 98% and >99% from HMF, respectively. Moreover, the catalytic performance of KF could remain for at least five consecutive cycles in the conversion of HMF to BHMF.

Thermal aromatic Claisen rearrangement and Strecker reaction of alkyl(allyl)-aryl ethers under green reaction conditions: Efficient and clean preparation of ortho-allyl phenols (naphthols) and alkyl(allyl)oxyarene-based γ-amino nitriles

Chemical transformations of 13 diverse allyl(alkyl)-aryl ethers, easily prepared using Williamson reaction of different hydroxyarenes and allyl bromide and alkyl (n-butyl, n-octyl) bromides, were studied. Thermal aromatic Claisen rearrangement of allyl-aryl ethers to obtain ortho-allyl phenols (naphthols) employing propylene carbonate as a nontoxic and biodegradable solvent was described for the first time. The use of this green solvent allowed to enhance notably product yields and reduce significantly the reaction time comparing with the use of 1,2-dichlorobenzene, toxic solvent, which is traditionally employed in this type of Claisen rearrangement. Three-component Strecker reaction of selected alkyl(allyl)-aryl ethers with formyl function on aryl fragment, piperidine and potassium cyanide in the presence of sulfuric acid supported on silica gel (SSA, SiO2-O-SO3H) under mild reaction conditions was used in the preparation of new γ-amino nitriles, analogues of alkaloid girgensohnine [2-(4-hydroxyphenyl)-2-(piperidin-1-yl)acetonitrile], a perspective biological model in the search for new insecticidal agrochemicals against Aedes aegypti. The use of SSA, an inexpensive and reusable solid catalyst, allowed to obtain new series of 2-[4-alkyl(allyl)oxyphenyl]-2-(piperidin-1-yl)acetonitriles in short time at room temperature with good yields.

Synthesis and Characterization of Hybrid Mg(OH)2 and CeCO3OH Composite with Improved Activity Towards Henry Reaction

AbstractA new approach was developed for carbon–carbon bond formation via Henry reaction using a mixture of Mg(OH)2 and CeCO3OH (MgCe‐HDC). The MgCe‐HDC was synthesized using a co‐precipitation method and was characterized by SEM, XRD, FTIR, TGA‐DTA, and AFM. The effects of temperature, solvent, and the amount of catalyst were investigated to find the optimum reaction conditions. The highest yield of nitroaldol product, 92 %, was achieved over the reusable solid base catalyst in solvent‐free conditions at 20 °C.

Electrochemical Evaluation of Catalytic Activity of Various Types of LDH/Mo10V2-Pd: Application of FeNi/Mo10V2-Pd as an Efficient and Reusable Nano Catalyst in the Heck Coupling Reactions

Palladium nano particles deposited on various forms of layered double hydroxide intercalated 10-molybdovanado phosphate (M(III)M(II)/Mo10V2-Pd) were synthesized. Their electrocatalytic behavior and collaboration of all components of synthesized catalysts were evaluated in Heck coupling reaction. According to the obtained results from electrochemical and catalytic investigations, FeNi/Mo10V2-Pd was chosen as the best in term of productivity. The structural features of FeNi/Mo10V2-Pd were characterized by SEM, EDX, TEM, FT-IR, XRD, ICP-AES, LSV, chronoamperometry and CV analyses. The presence of Mo10V2 improved the catalytic activity of FeNi-Pd in the Heck coupling reaction. Also collaboration of Pd and Mo10V2 with FeNi LDH as a support was studied. This reusable solid catalyst exhibited excellent activity and the methodology is applicable to diverse substrates providing good to excellent yields of desired products. This method has advantages of high yields, low reaction times, elimination of ligand and base, heterogeneous reusable catalysts and simple methodology.

Incorporation of palladium nanoparticles and 10-molybdovanado phosphoric acid in FeCo layered double hydroxide structure: electrochemical and catalytic investigation for Mizoroki–Heck coupling reactions

Palladium (Pd) has been immobilized on FeCo layered double hydroxide (LDH) intercalated 10-molybdovanado phosphate (FeCo/Mo10V2-Pd) for the first time. The structure was characterized using various characterization techniques. The electrocatalytic behavior of FeCo/Mo10V2-Pd was investigated using cyclic voltammetry and linear sweep voltammetry techniques. The presence of Mo10V2 enhanced the catalytic activity of FeCo-Pd in the Heck coupling reaction. Also, the collaboration of Pd and Mo10V2 with LDH as a mesoporous support was studied. These reusable solid catalysts exhibited excellent activity, and the methodology is applicable to diverse substrates providing good to excellent yields of the desired products. This method has advantages of high yields, low reaction times, elimination of ligand and base, heterogeneous catalysts and simple methodology. It is notable that FeCo/Mo10V2-Pd can easily separate from the reaction mixture using an external magnet and reused for at least four successive runs without any considerable decrease in its catalytic activity.

One-pot Reductive Amination of Carbonyl Compounds with NaBH 4 -B(OSO 3 H) 3 /SiO 2 in Acetonitrile and in Solvent-free Condition

An efficient one-pot procedure for the direct reductive amination of aldehyde and ketones was achieved in the presence of sodium borohydride by using B(OSO3H)3/SiO2(SBSA) as the reusable solid catalyst in acetonitrile and solvent-free conditions. Both aromatic and aliphatic aldehyde reacted well to give the corresponding amines in excellent yields. All the products are known and well-characterized. The catalyst is recoverable and could be easily recycled by filtration and reused several times without any significant loss of its activity. SBSA acts as a dual Brønsted/Lewis acid that is an air-stable and cost-effective solid acid.

An Efficient Eco-Friendly Synthesis of Pyran Annulated Heterocyclic Systems under Conventional Heating and Microwave Irradiation in Solvent-Free Conditions

ABSTRACT1,4-Diazabicyclo[2.2.2]octane (DABCO) has been used as an efficient and reusable solid base catalyst for the rapid and green synthesis of pyran annulated heterocyclic ring systems by the condensation reaction of various activated CH-acids and tetracyanoethylene under conventional heating and microwave irradiation in solvent-free conditions. Excellent yield, very short reaction time (2–5 min), operatinal simplity, easy work-up procedure, avoidance of hazardous or toxic catalysts, and organic solvents are the main advantages of this green methodology which makes it more economic than the other conventional methods.

Heteropoly acid/NaY zeolite as a reusable solid catalyst for highly efficient synthesis of gem-dihydroperoxides and 1,2,4,5-tetraoxanes

gem-Dihydroperoxides and 1,2,4,5-tetraoxanes were synthesised from aldehydes and ketones catalysed by heteropoly acid/NaY zeolite (HPA/NaY) as a new, effective and reusable solid catalyst using 30% aqueous hydrogen peroxide at room temperature. The reactions proceeded with high rates and excellent yields.

One-Pot, Sequential Four-Component Synthesis of Benzo[a]chromeno[2,3-c]phenazine Derivatives Using SiO2–SO3H as an Efficient and Recoverable Catalyst Under Conventional Heating and Microwave Irradiation

ABSTRACTSilica sulfuric acid (SiO2–SO3H) has been used as an effective and reusable solid catalyst for the one-pot, two-step, four-component microwave-assisted synthesis of benzo[a]chromeno[2,3-c]phenazine derivatives by the condensation reaction of 2-hydroxynaphthalene-1,4-dione, o-phenylenediamine, aldehydes, and cyclic 1,3-dicarbonyl compounds. This new procedure has a number of advantages such as: high yields, very short reaction time, operational simplicity, simple work-up procedures and avoidance of hazardous or toxic catalysts, and organic solvents and is devoid of inessential derivatization and generation of hazardous substances. Moreover, the catalyst shows high thermal stability and can be recovered and reused without loss of reactivity.

Theophylline as a new and green catalyst for the one-pot synthesis of spiro[benzo[a]pyrano[2,3-c]phenazine] and benzo[a]pyrano[2,3-c]phenazine derivatives under solvent-free conditions

A green, convenient, high yielding and one-pot procedure for the synthesis of novel spiro[benzo[a]pyrano[2,3-c]phenazine] derivatives by domino multi-component condensation reaction between 2-hydroxynaphthalene-1,4-dione, benzene-1,2-diamines, ninhydrine, and malononitrile in the presence of a catalytic amount of 1,3-dimethyl-7H-purine-2,6-dione (theophylline) as an expedient, eco-friendly and reusable solid base catalyst under thermal, microwave irradiation and solvent-free conditions. This procedure has also been applied successfully for the synthesis of benzo[a]pyrano[2,3-c]phenazines.

Chitosan as a reusable solid base catalyst for Knoevenagel condensation reaction

In the present work, the commercially available chitosan is reported as a heterogeneous solid base catalyst for Knoevenagel condensation reaction of carbonyl compounds with malononitrile under mild reaction conditions. Chitosan is characterized by powder XRD, IR and elemental analysis. The catalytic activity of chitosan is evaluated in Knoevenagel condensation reaction of benzaldehyde and malononitrile as model substrates and the optimized reaction conditions are further used to expand its activity with various substrates. In addition, the catalyst stability is also examined by performing reusability, leaching experiments and it is observed that the catalyst can be reused for four times with no significant drop in its activity.

Synthesis of N-methyl imines in the presence of poly(N-vinylpyridine) as a reusable solid base catalyst by a mechanochemical process

The synthesis of N-methyl imines was performed in the presence of catalytic amounts of poly(4-vinylpyridine) in high yields and rapidly at room temperature by a ball milling process. This new method has some advantages including good yields for relatively unreactive carbonyl compounds and short reaction times as well as being green in terms of avoiding the use of toxic reagents and solvents. The major advantage of this process is that the catalyst can be easily regenerated and reused several times without any significant loss of activity.

ChemInform Abstract: A New Protocol for One‐Pot Synthesis of Tetrasubstituted Pyrroles Using Tungstate Sulfuric Acid as a Reusable Solid Catalyst.

Abstract A variety of tetrasubstituted pyrroles were synthesized in good yields in a one-pot, three-component reaction of α-hydroxyketones, malononitrile, and ammonium acetate using tungstate sulfuric acid (TSA) under solvent-free conditions.