Development of olefin epoxidation heterogeneous catalysts by the sol–gel and grafting methods

Replacing fossil fuels with biodiesel enables the emission of greenhouse gases to be decreased and reduces dependence on fossil fuels in countries with poor natural resources. Biodiesel can be produced by an esterification reaction between free fatty acids (FFAs) and methanol or by transesterification of triglycerides from oils. Both reactions require homogeneous or heterogeneous catalysis. Production of biodiesel catalyzed by heterogeneous catalysts seems to be the preferred route, enabling easy product separation. As we have previously shown, the Lewis acids AlCl3 and BF3 can serve as highly efficient catalysts under ultrasonic activation. The present study focused on the development of oleic acid (OA) esterification with methanol by the same catalysts immobilized in silica matrices using the sol–gel synthesis route. During the course of immobilization, AlCl3 converts to AlCl3 × 6H2O (aluminite) and BF3 is hydrolyzed with the production of B2O3. The immobilized catalysts can be reused or involved in a continuous process. The possibility of biodiesel production using immobilized catalysts under ultrasonic activation is shown for the conversion of FFAs into biodiesel in batch and continuous mode.

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Fabrication of Core-Shell Structural SiO2@H3[PM12O40] Material and Its Catalytic Activity

Journal of Nanomaterials ◽

10.1155/2014/835931 ◽

2014 ◽

Vol 2014 ◽

pp. 1-8

Author(s):

Xin Yang ◽

Junhai Wang ◽

Qi Zhang ◽

Xu Wang ◽

Linlin Xu ◽

...

Keyword(s):

Catalytic Activity ◽

Heterogeneous Catalysts ◽

Sol Gel ◽

Operating Conditions ◽

Core Shell ◽

Catalytic Wet Air Oxidation ◽

Air Oxidation ◽

Wet Air Oxidation ◽

Heterogeneous Catalytic ◽

Room Condition

Through a natural tree grain template and sol-gel technology, the heterogeneous catalytic materials based on polyoxometalate compounds H3[PM12O40] encapsulating SiO2: SiO2@H3[PM12O40] (SiO2@PM12, M = W, Mo) with core-shell structure had been prepared. The structure and morphology of the core-shell microspheres were characterized by the XRD, IR spectroscopy, UV-Vis absorbance, and SEM. These microsphere materials can be used as heterogeneous catalysts with high activity and stability for catalytic wet air oxidation of pollutant dyes safranine T (ST) at room condition. The results show that the catalysts have excellent catalytic activity in treatment of wastewater containing 10 mg/L ST, and 94% of color can be removed within 60 min. Under different cycling runs, it is shown that the catalysts are stable under such operating conditions and the leaching tests show negligible leaching effect owing to the lesser dissolution.

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Manganese- and Cobalt-Based Coordination Networks as Promising Heterogeneous Catalysts for Olefin Epoxidation Reactions

Inorganic Chemistry ◽

10.1021/ic502772k ◽

2015 ◽

Vol 54 (6) ◽

pp. 2603-2615 ◽

Cited By ~ 23

Author(s):

Girijesh Kumar ◽

Gulshan Kumar ◽

Rajeev Gupta

Keyword(s):

Heterogeneous Catalysts ◽

Olefin Epoxidation ◽

Coordination Networks

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Sol–gel synthesis of heterogeneous catalysts from aqueous solutions

Catalysis Today ◽

10.1016/s0920-5861(98)00034-0 ◽

1998 ◽

Vol 41 (1-3) ◽

pp. 3-19 ◽

Cited By ~ 98

Author(s):

J Livage

Keyword(s):

Aqueous Solutions ◽

Heterogeneous Catalysts ◽

Sol Gel ◽

Sol Gel Synthesis

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Catalytic Materials by Design from Hybrid Organic-Inorganics

MRS Proceedings ◽

10.1557/proc-519-41 ◽

1998 ◽

Vol 519 ◽

Cited By ~ 3

Author(s):

Joël ◽

J.E. Moreau ◽

Michel Wong Chi Man

Keyword(s):

Heterogeneous Catalysts ◽

Sol Gel ◽

Inorganic Materials ◽

Hybrid Network ◽

Intrinsic Properties ◽

Reaction Conditions ◽

Molecular Precursors ◽

Catalytic Materials ◽

Materials By Design ◽

Gel Processing

AbstractThe sol-gel processing of appropriated molecular precursors easily leads to a variety of hybrid organic-inorganic materials with intrinsic properties. This approach is increasingly becoming an interesting way to prepare heterogeneous catalysts. The paper will focus on the use of hybrids for the preparation of selective catalytic materials. Two examples of the use of hybrid polysilsesquioxanes polymers will be given. i) The tailoring of the pore structure of silicas, under mild reaction conditions, based on the temporary introduction of different organic substructures in the hybrid network of polysilsesquioxane gels will be discussed. ii) Also the preparation of new chiral hybrid supports for enantioselective catalysis will be presented.

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Metal Organic Frameworks as Heterogeneous Catalysts in Olefin Epoxidation and Carbon Dioxide Cycloaddition

Inorganics ◽

10.3390/inorganics9110081 ◽

2021 ◽

Vol 9 (11) ◽

pp. 81

Author(s):

Alessia Tombesi ◽

Claudio Pettinari

Keyword(s):

Carbon Dioxide ◽

Coordination Polymers ◽

Heterogeneous Catalysts ◽

Metal Organic Frameworks ◽

Metal Species ◽

Olefin Epoxidation ◽

Crystalline Materials ◽

Recent Developments ◽

Metal Organic ◽

New Research

Metal–organic frameworks (MOFs) are a family of porous crystalline materials that serve in some cases as versatile platforms for catalysis. In this review, we overview the recent developments about the use of these species as heterogeneous catalysts in olefin epoxidation and carbon dioxide cycloaddition. We report the most important results obtained in this field relating them to the presence of specific organic linkers, metal nodes or clusters and mixed-metal species. Recent advances obtained with MOF nanocomposites were also described. Finally we compare the results and summarize the major insights in specific Tables, outlining the major challenges for this emerging field. This work could promote new research aimed at producing coordination polymers and MOFs able to catalyse a broader range of CO2 consuming reactions.

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