Hierarchically porous AlPO-5-based microspheres as heterogeneous catalysts for the synthesis of 5-substituted 1H-tetrazoles via [3+2] cycloaddition

2014 ◽  
Vol 38 (7) ◽  
pp. 3078-3083 ◽  
Author(s):  
Dan Kong ◽  
Yanyan Liu ◽  
Juan Zhang ◽  
Hongbian Li ◽  
Xiangyu Wang ◽  
...  
Keyword(s):  
Heterogeneous Catalysts ◽  
Hierarchically Porous ◽  
Effective Catalyst ◽  
Substituted 1

W-containing AlPO-5 microspheres were effective catalyst for the synthesis of 5-substituted 1H-tetrazoles by [3+2] cycloaddition.

ChemInform Abstract: P2O5/SiO2: A Simple and Effective Catalyst for the Synthesis of N-Substituted 1-Alkyl and 1-Aryl 3-Aminoisoquinolines.

ChemInform ◽  
2013 ◽  
Vol 44 (42) ◽  
pp. no-no
Author(s):  
Leticia J. Mendez ◽  
Alicia S. Canepa ◽  
Ruben Rimada ◽  
Rodolfo D. Bravo
Keyword(s):  
Effective Catalyst ◽  
Substituted 1

scholarly journals Facile and innovative catalytic protocol for intramolecular Friedel–Crafts cyclization of Morita–Baylis–Hillman adducts: Synergistic combination of chiral (salen)chromium(III)/BF3·OEt2 catalysis

2021 ◽  
Vol 17 ◽  
pp. 2186-2193
Author(s):  
Karthikeyan Soundararajan ◽  
Helen Ratna Monica Jeyarajan ◽  
Raju Subimol Kamarajapurathu ◽  
Karthik Krishna Kumar Ayyanoth
Keyword(s):  
Reaction Conditions ◽  
Effective Catalyst ◽  
Practical Procedure ◽  
Synergistic Combination ◽  
Substituted 1

The chiral (salen)Cr(III)/BF3·OEt2 catalytic combination was found to be an effective catalyst for intramolecular Friedel–Crafts cyclization of electron-deficient Morita–Baylis–Hillman adducts. In presence of mild reaction conditions the chiral (salen)Cr(III)/BF3·OEt2 complex affords 2-substituted-1H-indenes from unique substrates of Morita–Baylis–Hillman adducts via an easy operating practical procedure.

ChemInform Abstract: Hierarchically Porous AlPO-5-Based Microspheres as Heterogeneous Catalysts for the Synthesis of 5-Substituted 1H-Tetrazoles via [3 + 2] Cycloaddition.

ChemInform ◽  
2014 ◽  
Vol 45 (50) ◽  
pp. no-no ◽  
Author(s):  
Dan Kong ◽  
Yanyan Liu ◽  
Juan Zhang ◽  
Hongbian Li ◽  
Xiangyu Wang ◽  
...  
Keyword(s):  
Heterogeneous Catalysts ◽  
Hierarchically Porous

Porous polymer catalysts with hierarchical structures

2015 ◽  
Vol 44 (17) ◽  
pp. 6018-6034 ◽  
Author(s):  
Qi Sun ◽  
Zhifeng Dai ◽  
Xiangju Meng ◽  
Feng-Shou Xiao
Keyword(s):  
Mass Transfer ◽  
Heterogeneous Catalysts ◽  
Hierarchical Structures ◽  
Porous Polymer ◽  
Hierarchically Porous ◽  
Highly Efficient

The hierarchically porous polymer catalysts with fast mass transfer provide great opportunities for designing highly efficient heterogeneous catalysts.

scholarly journals Retraction: Monodisperse Pt NPs@rGO as highly efficient and reusable heterogeneous catalysts for the synthesis of 5-substituted 1H-tetrazole derivatives

2021 ◽  
Author(s):  
İbrahim Esirden ◽  
Muharrem Kaya
Keyword(s):  
Heterogeneous Catalysts ◽  
Highly Efficient ◽  
Substituted 1 ◽  
Tetrazole Derivatives

Retraction of ‘Monodisperse Pt NPs@rGO as highly efficient and reusable heterogeneous catalysts for the synthesis of 5-substituted 1H-tetrazole derivatives’ by İbrahim Esirden et al., Catal. Sci. Technol., 2015, 5, 4452–4457, DOI: 10.1039/C5CY00864F.

Monodisperse Pt NPs@rGO as highly efficient and reusable heterogeneous catalysts for the synthesis of 5-substituted 1H-tetrazole derivatives

2015 ◽  
Vol 5 (9) ◽  
pp. 4452-4457 ◽  
Author(s):  
İbrahim Esirden ◽  
Esma Erken ◽  
Muharrem Kaya ◽  
Fatih Sen
Keyword(s):  
Reaction Time ◽  
Heterogeneous Catalysts ◽  
Highly Efficient ◽  
Excellent Yield ◽  
Substituted 1 ◽  
Tetrazole Derivatives

Monodisperse Pt NPs@rGO catalyst showed excellent yield and the shortest reaction time for the synthesis of 5-substituted 1H-tetrazoles.

What catalysis needs from the electron microscopist

1988 ◽  
Vol 46 ◽  
pp. 694-695
Author(s):  
Alexis T. Bell
Keyword(s):  
Active Sites ◽  
Heterogeneous Catalysts ◽  
Catalyst Deactivation ◽  
Surface Composition ◽  
Internal Surface ◽  
Active Phase ◽  
Atomic Scale ◽  
Metal Catalyst ◽  
Internal Surface Area ◽  
Porous Support

Heterogeneous catalysts, used in industry for the production of fuels and chemicals, are microporous solids characterized by a high internal surface area. The catalyticly active sites may occur at the surface of the bulk solid or of small crystallites deposited on a porous support. An example of the former case would be a zeolite, and of the latter, a supported metal catalyst. Since the activity and selectivity of a catalyst are known to be a function of surface composition and structure, it is highly desirable to characterize catalyst surfaces with atomic scale resolution. Where the active phase is dispersed on a support, it is also important to know the dispersion of the deposited phase, as well as its structural and compositional uniformity, the latter characteristics being particularly important in the case of multicomponent catalysts. Knowledge of the pore size and shape is also important, since these can influence the transport of reactants and products through a catalyst and the dynamics of catalyst deactivation.

Electron holography of catalysts

1995 ◽  
Vol 53 ◽  
pp. 416-417
Author(s):  
A. K. Datye ◽  
D. S. Kalakkad ◽  
L. F. Allard ◽  
E. Völkl
Keyword(s):  
Heterogeneous Catalysts ◽  
High Surface ◽  
High Surface Area ◽  
Atomic Scale ◽  
Nano Particles ◽  
Phase Image ◽  
Electron Holography ◽  
Specimen Thickness ◽  
Phase Information ◽  
Particle Structure

The active phase in heterogeneous catalysts consists of nanometer-sized metal or oxide particles dispersed within the tortuous pore structure of a high surface area matrix. Such catalysts are extensively used for controlling emissions from automobile exhausts or in industrial processes such as the refining of crude oil to produce gasoline. The morphology of these nano-particles is of great interest to catalytic chemists since it affects the activity and selectivity for a class of reactions known as structure-sensitive reactions. In this paper, we describe some of the challenges in the study of heterogeneous catalysts, and provide examples of how electron holography can help in extracting details of particle structure and morphology on an atomic scale.Conventional high-resolution TEM imaging methods permit the image intensity to be recorded, but the phase information in the complex image wave is lost. However, it is the phase information which is sensitive at the atomic scale to changes in specimen thickness and composition, and thus analysis of the phase image can yield important information on morphological details at the nanometer level.

Quantitative nano-characterization of heterogeneous catalysts

1995 ◽  
Vol 53 ◽  
pp. 398-399
Author(s):  
P.A. Crozier ◽  
M. Pan
Keyword(s):  
Heterogeneous Catalysts ◽  
Low Dose ◽  
Imaging Techniques ◽  
Structural Features ◽  
Catalyst Characterization ◽  
New Developments ◽  
Double Phase ◽  
Phase Systems ◽  
Dose Imaging

Heterogeneous catalysts can be of varying complexity ranging from single or double phase systems to complicated mixtures of metals and oxides with additives to help promote chemical reactions, extend the life of the catalysts, prevent poisoning etc. Although catalysis occurs on the surface of most systems, detailed descriptions of the microstructure and chemistry of catalysts can be helpful for developing an understanding of the mechanism by which a catalyst facilitates a reaction. Recent years have seen continued development and improvement of various TEM, STEM and AEM techniques for yielding information on the structure and chemistry of catalysts on the nanometer scale. Here we review some quantitative approaches to catalyst characterization that have resulted from new developments in instrumentation.HREM has been used to examine structural features of catalysts often by employing profile imaging techniques to study atomic details on the surface. Digital recording techniques employing slow-scan CCD cameras have facilitated the use of low-dose imaging in zeolite structure analysis and electron crystallography. Fig. la shows a low-dose image from SSZ-33 zeolite revealing the presence of a stacking fault.

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