scholarly journals Pd–Ce/ZIF-8 Nanocomposite for Catalytic Extraction of Sinomenine from Sinomenium acutum

Catalysts ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 174
Author(s):  
Yinghuai Zhu ◽  
Zhiyu Bai
Keyword(s):  
Heterogeneous Catalysts ◽  
Supported Catalysts ◽  
Catalyst Recycling ◽  
Particle Size Range ◽  
Zeolitic Imidazolate Framework ◽  
Sinomenium Acutum ◽  
Naturally Occurring ◽  
Loading Amount ◽  
Optimized Conditions ◽  
Catalytic Extraction

Sinomenine is a naturally occurring alkaloid and commonly used as one of the bioactive drug components in rheumatoid arthritis (RA) treatment in the clinic. Varying supported palladium-based catalysts have been synthesized and examined as heterogeneous catalysts for catalytic extraction of sinomenine from Sinomenium acutum. Among various examined supported catalysts, Pd–Ce/ZIF-8 (zeolitic imidazolate framework-8) demonstrates promising catalytic activity in the extraction reaction with an improved yield of 2.15% under optimized conditions. The catalyst composite can be recovered by centrifuging, and reused. A total of three catalyst recycling processes were performed with constant activity. The catalyst Pd–Ce/ZIF-8 has a particle size range of 2–12 nm and a total Pd–Ce loading amount of 5.1 wt% (ZIF-8).

An Overview of Metal-organic Frameworks-based Acid/Base Catalysts for Biofuel Synthesis

2020 ◽  
Vol 24 (16) ◽  
pp. 1876-1891
Author(s):  
Qiuyun Zhang ◽  
Yutao Zhang ◽  
Jingsong Cheng ◽  
Hu Li ◽  
Peihua Ma
Keyword(s):  
Alternative Fuels ◽  
Heterogeneous Catalysts ◽  
Supported Catalysts ◽  
Metal Organic Framework ◽  
Metal Organic Frameworks ◽  
Flexible Structures ◽  
Biodiesel Production ◽  
Biodiesel Synthesis ◽  
Metal Organic ◽  
Organic Framework

Biofuel synthesis is of great significance for producing alternative fuels. Among the developed catalytic materials, the metal-organic framework-based hybrids used as acidic, basic, or supported catalysts play major roles in the biodiesel production. This paper presents a timely and comprehensive review of recent developments on the design and preparation of metal-organic frameworks-based catalysts used for biodiesel synthesis from various oil feedstocks, including MILs-based catalysts, ZIFs-based catalysts, UiO-based catalysts, Cu-BTC-based catalysts, and MOFs-derived porous catalysts. Due to their unique and flexible structures, excellent thermal and hydrothermal stability, and tunable host-guest interactions, as compared with other heterogeneous catalysts, metal-organic framework-based catalysts have good opportunities for application in the production of biodiesel at industrial scale.

scholarly journals Recyclable Catalysts for Alkyne Functionalization

Molecules ◽  
2021 ◽  
Vol 26 (12) ◽  
pp. 3525
Author(s):  
Leslie Trigoura ◽  
Yalan Xing ◽  
Bhanu P. S. Chauhan
Keyword(s):  
Supported Catalysts ◽  
Metal Organic Framework ◽  
Metal Nanoparticle ◽  
Homogeneous Catalyst ◽  
Catalyst Recycling ◽  
Catalytic Systems ◽  
Recyclable Catalysts ◽  
Metal Organic ◽  
Porous Organic Framework ◽  
Organic Framework

In this review, we present an assessment of recent advances in alkyne functionalization reactions, classified according to different classes of recyclable catalysts. In this work, we have incorporated and reviewed the activity and selectivity of recyclable catalytic systems such as polysiloxane-encapsulated novel metal nanoparticle-based catalysts, silica–copper-supported nanocatalysts, graphitic carbon-supported nanocatalysts, metal organic framework (MOF) catalysts, porous organic framework (POP) catalysts, bio-material-supported catalysts, and metal/solvent free recyclable catalysts. In addition, several alkyne functionalization reactions have been elucidated to demonstrate the success and efficiency of recyclable catalysts. In addition, this review also provides the fundamental knowledge required for utilization of green catalysts, which can combine the advantageous features of both homogeneous (catalyst modulation) and heterogeneous (catalyst recycling) catalysis.

Laser electrodispersion as a new chlorine-free method for the production of highly effective metal-containing supported catalysts

2012 ◽  
Vol 84 (3) ◽  
pp. 495-508 ◽  
Author(s):  
Ekaterina S. Lokteva ◽  
Anton A. Peristyy ◽  
Natalia E. Kavalerskaya ◽  
Elena V. Golubina ◽  
Lada V. Yashina ◽  
...  
Keyword(s):  
Gas Phase ◽  
High Stability ◽  
Heterogeneous Catalysts ◽  
Supported Catalysts ◽  
Promising Technique ◽  
Wet Impregnation ◽  
Oxide Supports ◽  
Highly Active ◽  
Specific Catalytic Activity ◽  
Free Metal

Laser electrodispersion (LED) of metals is a promising technique for the preparation of heterogeneous catalysts as an alternative to wet impregnation of supports with the corresponding salt solutions. The LED technique can be used to deposit highly active chloride- and nitrate-free metal nanoparticles onto carbon or oxide supports. We report preparation and properties of new Ni-, Pd-, and Au-containing alumina-supported catalysts with low metal loadings (10–3–10–4 % mass) and their comparison with the previously studied carbon (Sibunit) supported systems. The catalysts demonstrate high stability and extremely high specific catalytic activity (by 2–3 orders of magnitude higher than for traditional catalysts) in the gas-phase hydrodechlorination (HDC) of chlorobenzene (CB).

Synthesis of fatty 1,2,4-trioxanes by peracetalisation of β-hydroxy hydroperoxides

Synthesis ◽  
2021 ◽  
Author(s):  
Thomas De Dios Miguel ◽  
Dan Louvel ◽  
Killian Onida ◽  
Adeline Lavoignat ◽  
Stephane Picot ◽  
...  
Keyword(s):  
Sulfonic Acid ◽  
Heterogeneous Catalysts ◽  
Antimalarial Activity ◽  
Acid Catalyst ◽  
Methyl Tert Butyl Ether ◽  
Significant Activity ◽  
Butyl Ether ◽  
Aliphatic Aldehydes ◽  
Toluene Sulfonic Acid ◽  
Optimized Conditions

The peracetalisation of a β-hydroxy hydroperoxide derived from methyl oleate was studied using benzaldehyde as a model substrate to give the corresponding fatty 1,2,4-trioxane. The desired product was obtained as a mixture of regioisomers but only one diastereoisomer of each was formed. The nature of the acid catalyst was studied and both para-toluene sulfonic acid (PTSA) and Amberlyst A35 (A35) were found to be efficient homogeneous and heterogeneous catalysts, respectively. The nature of the solvent was also investigated and ethereal solvents such as 2-methyltetrahydrofuran (2-MeTHF), methyl tert-butyl ether (MTBE) and cyclopentyl methyl ether (CPME) gave the best NMR yield (85%) for the preparation of the fatty trioxane. The optimized conditions were applied to a range of aromatic and aliphatic aldehydes and the corresponding 1,2,4-trioxanes were isolated with 30-91% yields (21 examples). The antimalarial activity of 3 trioxanes was studied against Plasmodium falciparum, however, no significant activity was detected (IC50 > 1600 nM).

scholarly journals Depolymerization of Poly(ethylene terephthalate) Wastes through Glycolysis using Lewis Acidic Bentonite Catalysts

2019 ◽  
Vol 32 (1) ◽  
pp. 187-191
Author(s):  
Gopal Jeya ◽  
Murugan Anbarasu ◽  
Ravikumar Dhanalakshmi ◽  
Viswanathan Vinitha ◽  
Vajiravelu Sivamurugan
Keyword(s):  
Metal Ion ◽  
Heterogeneous Catalysts ◽  
Ethylene Terephthalate ◽  
Nitrogen Adsorption ◽  
Impregnation Method ◽  
Wet Impregnation ◽  
Poly Ethylene Terephthalate ◽  
Acidic Nature ◽  
Poly Ethylene ◽  
Optimized Conditions

In the present investigation, the authors explored the depolymerization of waste poly(ethylene terephthalate) (PET) beverage bottles using glycolysis (transesterification) catalyzed by Al3+, Fe3+ and Zn2+ impregnated bentonite catalysts. Heterogeneous catalysts such as clay, zeolite, alumina etc. preferred over homogeneous catalysts, thus we focused on the development of solid acid catalysts based on economically viable clay catalysts. The desired Lewis acidic nature was introduced by wet impregnation method at variable metal ion to clay ratio such as 0.5, 1.0, 2.0, 3.0, 4.0 and 5.0 wt. %. The effect of metal-ion loading on the surface area, pore volume and crystalline nature of the bentonite has been evaluated by nitrogen adsorption and desorption studies and XRD. The PET wastes collected from post-consumer beverage bottles were depolymerized using ethylene glycol as a glycolyting agent afforded bis(2-hydroxy ethyl)terephthalate (BHET) in 85-90 % yield under optimized conditions. The yield of BHET was observed to be increasing with increase in Lewis acidic metal ions loading from 0.5 to 4.0 wt. % as well as increase in catalysts to PET ratio. Among the catalysts, Al3+ and Zn2+-bentonite catalysts showed higher yield of BHET up to 90 % at 4 and 5 wt. % loading of metal-ion.

In situ PXRD studies of heterogeneous catalysts and pre-catalysts

2014 ◽  
Vol 70 (a1) ◽  
pp. C1178-C1178
Author(s):  
David Billing
Keyword(s):  
Heterogeneous Catalysts ◽  
Supported Catalysts ◽  
Phase Evolution ◽  
Multiwalled Carbon ◽  
Complex Phase ◽  
Catalytic Systems ◽  
Heterogeneous Processes ◽  
Carbon Nano Tubes ◽  
Diffraction Patterns

During the course of the last couple of years, my collaborators and I have studied a number of catalytic systems using a lab based PXRD facility at our disposal. Of particular interest to us has been the supported catalysts used in Fischer Tropsch catalysis as well as those used in the synthesis of multiwalled carbon nano tubes. These studies have all proven invaluable to the understanding of the often complex phase evolution that is an intricate and inherent part of the heterogeneous processes of interest to us. Selected results will be presented to illustrate the usefulness and value of these studies. For example below is the intensity profile of the diffraction patterns collected during the heat-treatment of the pre-catalyst: A – anatase, R – rutile, S – silicon, H – hematite and P – pseudobrookite

Recent Developments on the Synthesis of Biologically Significant bis/tris(indolyl)methanes under Various Reaction Conditions: A Review

2020 ◽  
Vol 24 (6) ◽  
pp. 583-621
Author(s):  
Arvind Singh ◽  
Gurpreet Kaur ◽  
Bubun Banerjee
Keyword(s):  
Ionic Liquids ◽  
Bioactive Compounds ◽  
Building Block ◽  
Heterogeneous Catalysts ◽  
Metal Catalysts ◽  
Reaction Conditions ◽  
Naturally Occurring ◽  
Wide Range ◽  
Anti Cancer ◽  
Recent Developments

Bis(indolyl)methane skeleton is the main building block of many naturally occurring bioactive compounds. Bis(indolyl)methanes are found to possess a wide range of pharmaceuitical efficacies. These important scaffolds are being used as anti-cancer, antioxidant, anti-bacterial, anti-inflammatory, and anti-proliferative agents. In this review, we summarized the latest developments on the synthesis of various bis/tris(indolyl)methane derivatives from the reactions of two equivalents of indoles and one equivalent of aldehydes or indole-3-carbaldehydes under various reaction conditions. More than hundred different catalysts were employed for these transformations which include various metal catalysts, ionic liquids, organocatalysts, surfactants, homogeneous, heterogeneous catalysts etc.

scholarly journals Styrene Oxidation by Copper(II) Complexes Salen-Type Encapsulated into Nay Zeolite

2013 ◽  
Vol 58 (4) ◽  
pp. 1291-1294
Author(s):  
I. Kuźniarska-Biernacka ◽  
M.A. Carvalho ◽  
I. Correia Neves ◽  
A. M. Fonseca ◽  
A. Lisińska-Czekaj ◽  
...  
Keyword(s):  
Schiff Base ◽  
Heterogeneous Catalysts ◽  
Moderate Activity ◽  
Nay Zeolite ◽  
Styrene Oxidation ◽  
Preparation Methods ◽  
Flexible Ligand ◽  
Complex Preparation ◽  
Optimized Conditions

Abstract The copper(II) complex with a Schiff-base salen-type ligand has been encapsulated in the nanopores of a NaY zeolite by using two different methodologies, the flexible ligand and in situ complex preparation methods. The encapsulated and non-encapsulated copper(II) complexes were screened as catalysts for styrene oxidation by using TBHP as the oxygen source in acetonitrile solvent. Under the optimized conditions, the catalysts exhibited moderate activity with higher selectivity to benzaldehyde. Both heterogeneous catalysts were found to be reusable after the catalytic cycle, but with some loss of activity

scholarly journals Xylose fermentation to ethanol by newGalactomyces geotrichumandCandida akabanensisstrains

PeerJ ◽  
2018 ◽  
Vol 6 ◽  
pp. e4673 ◽  
Author(s):  
Raquel V. Valinhas ◽  
Lílian A. Pantoja ◽  
Ana Carolina F. Maia ◽  
Maria Gabriela C.P. Miguel ◽  
Ana Paula F.C. Vanzela ◽  
...  
Keyword(s):  
Carbon Source ◽  
Ribosomal Rna ◽  
Xylose Fermentation ◽  
Plant Biomass ◽  
The Other ◽  
Liquid Media ◽  
Second Generation Biofuels ◽  
Naturally Occurring ◽  
Yeast Strains ◽  
Optimized Conditions

The conversion of pentoses into ethanol remains a challenge and could increase the supply of second-generation biofuels. This study sought to isolate naturally occurring yeasts from plant biomass and determine their capabilities for transforming xylose into ethanol. Three yeast strains with the ability to ferment xylose were isolated from pepper, tomato and sugarcane bagasse. The strains selected were characterized by morphological and auxanographic assays, and they were identified by homology analysis of 5.8 S and 26 S ribosomal RNA gene sequences. The identities of two lineages of microrganism were associated withGalactomyces geotrichum, and the other was associated withCandida akabanensis. Fermentative processes were conducted with liquid media containing only xylose as the carbon source. YP/Svalues for the production of ethanol ranging between 0.29 and 0.35 g g−1were observed under non-optimized conditions.

scholarly journals Synthesis of activated carbon sand their application in the synthesis of monometallic and bimetallic supported catalysts

2020 ◽  
Vol 5 (4) ◽  
pp. 190-196
Author(s):  
DALILA BOUSBA ◽  
CHAFIA SOBHI ◽  
AMNA ZOUAOUI ◽  
SOUAD BOUASLA
Keyword(s):  
Heterogeneous Catalysis ◽  
Heterogeneous Catalysts ◽  
Bimetallic Catalyst ◽  
Activated Carbons ◽  
Supported Catalysts ◽  
Chemical Properties ◽  
Environmentally Benign ◽  
Organic Transformations ◽  
Long Time ◽  
Physical And Chemical

Biomass-derived porous carbons are attractive materials for the synthesis of carbon-supported catalysts, carbonaceous catalysts are environmentally benign and could provide an important competitive advantage as compared to existing heterogeneous catalysts, however the surface properties of carbon materials and excellent physical and chemical properties are compatible with diverse catalysis reactions including organic transformations. Currently, activated carbons are one of well known carbonaceous materials for their catalytic properties and for use as support in heterogeneous catalysis. The supported catalysts have been successfully used in the chemical industries for a long time, in which carbon supported catalysts have allowed to a new chemical catalytic process, on the other hand Heterogeneous catalysis plays a key role in the manufacture of essential products in different fields. In this paper, we present a comparative study, between two main different methods for activated carbons (ACs) preparation namely, physical and chemical activations. Latter was prepared from agro-industrial biomass and used as a support to prepare monometallic (dry impregnation and excess impregnation) and bimetallic catalyst (successive impregnation and co impregnation).

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