scholarly journals Heterogenization of polyoxometalates as solid catalysts in aerobic oxidation of glycerol

2020 ◽  
Vol 10 (11) ◽  
pp. 3771-3781 ◽  
Author(s):  
Meilin Tao ◽  
Yue Li ◽  
Yiming Li ◽  
Xueyan Zhang ◽  
Yurii V. Geletii ◽  
...  
Keyword(s):  
Heterogeneous Catalysts ◽  
Aerobic Oxidation ◽  
Solid Catalysts ◽  
Calcination Treatment

A series of heterogeneous catalysts LnPMo12O40 (L = Al3+, Fe3+, Cr3+, Ti4+, Zr4+, Zn2+) and HxPMo11LO39 (L = Zn2+, Cr3+, Fe3+, Al3+, Ti4+) were prepared using a simple calcination treatment and were evaluated in aerobic oxidation of glycerol.

scholarly journals Cobalt-Based Metal Organic Frameworks as Solids Catalysts for Oxidation Reactions

Catalysts ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 95
Author(s):  
Amarajothi Dhakshinamoorthy ◽  
Eva Montero Lanzuela ◽  
Sergio Navalon ◽  
Hermenegildo Garcia
Keyword(s):  
Aerobic Oxidation ◽  
High Surface ◽  
Metal Organic Frameworks ◽  
High Surface Area ◽  
Acid Sites ◽  
Crystalline Lattice ◽  
Oxidation Reactions ◽  
Solid Catalysts ◽  
Long Term Stability ◽  
Metal Organic

Metal organic frameworks (MOFs) are porous crystalline solids whose frameworks are constituted by metal ions/nodes with rigid organic linkers leading to the formation of materials having high surface area and pore volume. One of the unique features of MOFs is the presence of coordinatively unsaturated metal sites in their crystalline lattice that can act as Lewis acid sites promoting organic transformations, including aerobic oxidation reactions of various substrates such as hydrocarbons, alcohols, and sulfides. This review article summarizes the existing Co-based MOFs for oxidation reactions organized according to the nature of substrates like hydrocarbon, alcohol, olefin, and water. Both aerobic conditions and peroxide oxidants are discussed. Emphasis is placed on comparing the advantages of using MOFs as solid catalysts with respect to homogeneous salts in terms of product selectivity and long-term stability. The final section provides our view on future developments in this field.

scholarly journals Application of Heterogeneous Catalysts for Biodiesel Production from Microalgal Oil—A Review

Catalysts ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 1025
Author(s):  
Mohammed O. Faruque ◽  
Shaikh A. Razzak ◽  
Mohammad M. Hossain
Keyword(s):  
Heterogeneous Catalysts ◽  
Reaction Rate ◽  
Fossil Fuel ◽  
Solid Phase ◽  
Low Cost ◽  
Biodiesel Production ◽  
Terrestrial Plants ◽  
Homogeneous Catalysts ◽  
Microalgal Oil ◽  
Solid Catalysts

The depletion of fossil fuel reserves and increased environmental concerns related to fossil fuel production and combustion has forced the global communities to search for renewable fuels. In this regard, microalgae-based biodiesel has been considered as one of the interesting alternatives. Biodiesel production from the cultivation of microalgae is eco-friendly and sustainable. Moreover, microalgae have several advantages over other bioenergy sources, including their good photosynthetic capacity and faster growth rates. The productivity of microalgae per unit land area is also significantly higher than that of terrestrial plants. The produced microalgae biomass is rich with high quality lipids, which can be converted into biodiesel by transesterification reactions. Generally, the transesterification reactions are carried out in the presence of a homogeneous or heterogeneous catalyst. The homogeneous catalysts have many disadvantages, including their single use, slow reaction rate and saponification issues due to the presence of fatty acids in the feedstock. The acidic nature of the homogeneous catalysts also causes equipment corrosion. On the other hand, the heterogeneous catalysts offer several advantages, including their reusability, higher reaction rate and selectivity, easy product/catalyst separation and low cost. Due to these facts, the development of solid phase transesterification catalysts have been receiving growing interest. The present review is focused on the use of heterogeneous catalysts for biodiesel production from microalgal oil as a reliable feedstock with a comparison to other available feedstocks. It also highlights optimal reaction conditions for maximum biodiesel yields, reusability of the solid catalysts, cost, and environmental impact. The superior lipid content of microalgae and the efficient concurrent esterification and transesterification of the solid acid−base catalysts can offer new advancements in biodiesel production.

Biodiesel Production Using Mixed Solid Catalysts

2013 ◽  
Vol 824 ◽  
pp. 451-458
Author(s):  
A.K. Temu
Keyword(s):  
Active Sites ◽  
Heterogeneous Catalysts ◽  
Biodiesel Production ◽  
Environmentally Benign ◽  
Catalyst Loading ◽  
Yield Data ◽  
Continuous Processes ◽  
Solid Catalysts ◽  
Base Catalysts ◽  
Astm D6751

One of the disadvantages of homogeneous base catalysts in biodiesel production is that they cannot be reused or regenerated because they are consumed in the reaction. Besides, homogeneous catalysed process is not environmentally friendly because a lot of waste water is produced in the separation step. Unlike homogeneous, heterogeneous catalysts are environmentally benign, can be reused and regenerated, and could be operated in continuous processes, thus providing a promising option for biodiesel production. This paper presents catalytic activity of single and mixed solid catalysts in production of biodiesel from palm oil using methanol as well as ethanol at atmospheric pressure. The catalysts used are CaO, K2CO3, Al2O3, and CaO/K2CO3, CaO/Al2O3, K2CO3/Al2O3 mixtures. Results show that methanol is a better reactant with biodiesel yield ranging from 48 to 96.5% while ethanol gives yields ranging from 20 to 95.2%. The yield data for single catalysts range from 20 to 89.2% while that for mixed catalysts range from 52 to 96.5% indicating improvement in the activity by mixing the catalysts. The study also shows that biodiesel yield increases with catalyst loading which emphasizes the need for sufficient number of active sites. The properties of biodiesel produced compares well with ASTM D6751 and EN 14124 biodiesel standards.

scholarly journals Concluding remarks: progress toward the design of solid catalysts

2016 ◽  
Vol 188 ◽  
pp. 591-602 ◽  
Author(s):  
Bruce C. Gates
Keyword(s):  
Heterogeneous Catalysts ◽  
Performance Testing ◽  
Catalyst Design ◽  
Rapid Progress ◽  
Catalyst Structure ◽  
Solid Catalysts ◽  
Catalytic Materials ◽  
Fundamental Understanding ◽  
Scientists And Engineers ◽  
And Performance

The 2016 Faraday Discussion on the topic “Designing New Heterogeneous Catalysts” brought together a group of scientists and engineers to address forefront topics in catalysis and the challenge of catalyst design—which is daunting because of the intrinsic non-uniformity of the surfaces of catalytic materials. “Catalyst design” has taken on a pragmatic meaning which implies the discovery of new and better catalysts on the basis of fundamental understanding of the catalyst structure and performance. The presentations and discussion at the meeting illustrate the rapid progress in this understanding linked with improvements in spectroscopy, microscopy, theory, and catalyst performance testing. The following text includes a statement of recurrent themes in the discussion and examples of forefront science that evidences progress toward catalyst design.

Investigation of Phthalocyanine Catalysts for the Aerobic Synthesis of meso-Substituted Porphyrins

1997 ◽  
Vol 01 (04) ◽  
pp. 385-394 ◽  
Author(s):  
M. RAVIKANTH ◽  
CATALINA ACHIM ◽  
JOHN S. TYHONAS ◽  
ECKARD MÜNCK ◽  
JONATHAN S. LINDSEY
Keyword(s):  
Trifluoroacetic Acid ◽  
Room Temperature ◽  
Heterogeneous Catalysts ◽  
Mossbauer Spectroscopy ◽  
Oxidation Process ◽  
Aerobic Oxidation ◽  
Heterogeneous Reactions ◽  
High Concentration ◽  
Neutral Conditions ◽  
Homogeneous Reactions

The aerobic oxidation process for the synthesis of porphyrins, previously performed using 5 mol % p-chloranil (TCQ), 5 mol % iron(II) phthalocyanine ( FePc ) and stoichiometric amounts of O 2, has been refined using new phthalocyanine catalysts. Four phthalocyanine catalysts have been prepared, characterized by Mössbauer spectroscopy and examined for efficacy in the high concentration (0.1 M) synthesis of tetraphenylporphyrin at room temperature. Each phthalocyanine has been identified to be a μ-oxo dimer. Two catalysts are soluble (the μ-oxo dimers [(t-butyl)4 FePc ]2 O and [(n- C 6 H 13 O )4 FePc ]2 O ) and enable homogeneous reactions, while two are insoluble (the μ-oxo(1) and μ-oxo(2) dimers of FePc , ( FePc )2 O ) and give heterogeneous reactions. These four phthalocyanine compounds provide efficient catalysis at the 0.3–1 mol % level using only 1 mol % quinone or hydroquinone ( TCQ , DDQ , TCQH 2 or DDQH 2), affording ~25% yields of tetraphenylporphyrin in 60 min of oxidation. There are no discernible advantages of the homogeneous versus heterogeneous catalysts. The μ-oxo dimers are active, but FePc is inactive, at the 0.3 mol % level. The activity of the FePc sample at the 5 mol % level is attributed to residual μ-oxo dimer impurity. This aerobic oxidation process is superior to stoichiometric oxidation with TCQ or DDQ , and can be performed in the presence of BF 3· O ( Et )2, trifluoroacetic acid, or under neutral conditions.

Platinum nanoparticles supported on polymeric ionic liquid functionalized magnetic silica: effective and reusable heterogeneous catalysts for the selective oxidation of alcohols in water

RSC Advances ◽  
2016 ◽  
Vol 6 (108) ◽  
pp. 106769-106777 ◽  
Author(s):  
Esmail Vessally ◽  
Mostafa Ghasemisarabbadeih ◽  
Zeynab Ekhteyari ◽  
Rahim Hosseinzadeh-Khanmiri ◽  
Ebrahim Ghorbani-Kalhor ◽  
...  
Keyword(s):  
Ionic Liquid ◽  
Platinum Nanoparticles ◽  
Heterogeneous Catalysts ◽  
Aerobic Oxidation ◽  
Secondary Alcohols ◽  
Polymeric Ionic Liquid ◽  
Oxidation Of Alcohols ◽  
Recyclable Catalysts ◽  
Magnetic Silica ◽  
Magnetic Silica Nanoparticles

In this manuscript, we demonstrate that functionalized magnetic silica nanoparticles are efficient and recyclable catalysts for the selective, aerobic oxidation of various primary and secondary alcohols.

scholarly journals Designing effective solid catalysts for biomass conversion: aerobic oxidation of ethyl lactate to ethyl pyruvate

2018 ◽  
Vol 20 (8) ◽  
pp. 1866-1873 ◽  
Author(s):  
Wei Zhang ◽  
Bernd Ensing ◽  
Gadi Rothenberg ◽  
N. Raveendran Shiju
Keyword(s):  
Ethyl Pyruvate ◽  
Biomass Conversion ◽  
Aerobic Oxidation ◽  
Ethyl Lactate ◽  
Solid Catalyst ◽  
Solid Catalysts ◽  
Highly Efficient

A novel highly efficient solid catalyst in which vanadia is supported on pyridine-rich carbon is designed for the oxidation of ethyl lactate to ethyl pyruvate.

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