One methyl group makes a major difference: shape-selective catalysis by zeolite nanoreactors in liquid-phase condensation reactions

2017 ◽  
Vol 5 (33) ◽  
pp. 17464-17469 ◽  
Author(s):  
Chang Liu ◽  
Changyan Cao ◽  
Jian Liu ◽  
Xiaoshi Wang ◽  
Yanan Zhu ◽  
...  
Keyword(s):  
Liquid Phase ◽  
Active Sites ◽  
Knoevenagel Condensation ◽  
Shape Selectivity ◽  
Methyl Group ◽  
Condensation Reactions ◽  
Shape Selective ◽  
Selective Catalysis ◽  
Zeolite Crystals

Shape-selectivity with one-methyl-group-precision can be realized in Knoevenagel condensation reactions on zeolite crystals encapsulating basic active sites.

scholarly journals Maximizing sinusoidal channels of HZSM-5 for high shape-selectivity to p-xylene

2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Chuanfu Wang ◽  
Lei Zhang ◽  
Xin Huang ◽  
Yufei Zhu ◽  
Gang (Kevin) Li ◽  
...  
Keyword(s):  
High Activity ◽  
Chemical Industry ◽  
Chemical Separation ◽  
Shape Selectivity ◽  
Toluene Alkylation ◽  
Shape Selective ◽  
Toluene Methylation ◽  
Selective Catalysis ◽  
The Cost ◽  
Very High

Abstract The shape-selective catalysis enabled by zeolite micropore’s molecular-sized sieving is an efficient way to reduce the cost of chemical separation in the chemical industry. Although well studied since its discovery, HZSM-5′s shape-selective capability has never been fully exploited due to the co-existence of its different-sized straight channels and sinusoidal channels, which makes the shape-selective p-xylene production from toluene alkylation with the least m-xylene and o-xylene continue to be one of the few industrial challenges in the chemical industry. Rather than modifications which promote zeolite shape-selectivity at the cost of stability and reactivity loss, here inverse Al zoned HZSM-5 with sinusoidal channels predominantly opened to their external surfaces is constructed to maximize the shape-selectivity of HZSM-5 sinusoidal channels and reach > 99 % p-xylene selectivity, while keeping a very high activity and good stability ( > 220 h) in toluene methylation reactions. The strategy shows good prospects for shape-selective control of molecules with tiny differences in size.

Liquid phase aldol condensation reactions with MgO–ZrO2 and shape-selective nitrogen-substituted NaY

2011 ◽  
Vol 392 (1-2) ◽  
pp. 57-68 ◽  
Author(s):  
Wenqin Shen ◽  
Geoffrey A. Tompsett ◽  
Karl D. Hammond ◽  
Rong Xing ◽  
Fulya Dogan ◽  
...  
Keyword(s):  
Liquid Phase ◽  
Aldol Condensation ◽  
Condensation Reactions ◽  
Shape Selective ◽  
Aldol Condensation Reactions

scholarly journals A Ru-Complex Tethered to a N-Rich Covalent Triazine Framework for Tandem Aerobic Oxidation-Knoevenagel Condensation Reactions

Molecules ◽  
2021 ◽  
Vol 26 (4) ◽  
pp. 838
Author(s):  
Geert Watson ◽  
Parviz Gohari Derakhshandeh ◽  
Sara Abednatanzi ◽  
Johannes Schmidt ◽  
Karen Leus ◽  
...  
Keyword(s):  
Active Sites ◽  
Noble Metals ◽  
Heterogeneous Catalysts ◽  
Knoevenagel Condensation ◽  
Condensation Reaction ◽  
Aerobic Oxidation ◽  
Catalyst Support ◽  
Catalytic Performance ◽  
Condensation Reactions ◽  
Covalent Triazine Framework

Herein, a highly N-rich covalent triazine framework (CTF) is applied as support for a RuIII complex. The bipyridine sites within the CTF provide excellent anchoring points for the [Ru(acac)2(CH3CN)2]PF6 complex. The obtained robust RuIII@bipy-CTF material was applied for the selective tandem aerobic oxidation-Knoevenagel condensation reaction. The presented system shows a high catalytic performance (>80% conversion of alcohols to α, β-unsaturated nitriles) without the use of expensive noble metals. The bipy-CTF not only acts as the catalyst support but also provides the active sites for both aerobic oxidation and Knoevenagel condensation reactions. This work highlights a new perspective for the development of highly efficient and robust heterogeneous catalysts applying CTFs for cascade catalysis.

Knoevenagel Condensation Reactions of Cyano Malononitrile-Derivatives Under Microwave Radiation

2018 ◽  
Vol 22 (6) ◽  
pp. 519-532 ◽  
Author(s):  
Lucas Lima Zanin ◽  
David Esteban Quintero Jimenez ◽  
Luis Pina Fonseca ◽  
Andre Luiz Meleiro Porto
Keyword(s):  
Microwave Radiation ◽  
Knoevenagel Condensation ◽  
Condensation Reactions
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