scholarly journals Integrating membrane separation with gold‐catalyzed carboxylative cyclization of propargylamine and catalyst recovery via organic solvent nanofiltration

2021 ◽  
Author(s):  
Tahani ACA Bayrakdar ◽  
Fady Nahra ◽  
Dominic Ormerod ◽  
Steven P Nolan
Keyword(s):  
Organic Solvent ◽  
Membrane Separation ◽  
Catalyst Recovery ◽  
Organic Solvent Nanofiltration

scholarly journals Synthesis of C3-Symmetric Cinchona-Based Organocatalysts and Their Application in Asymmetric Michael and Friedel–Crafts Reactions

2021 ◽  
Author(s):  
Péter Kisszékelyi ◽  
Zsuzsanna Fehér ◽  
Sándor Nagy ◽  
Péter Bagi ◽  
Petra Kozma ◽  
...  
Keyword(s):  
Organic Solvent ◽  
Asymmetric Catalysis ◽  
Michael Reaction ◽  
Supported Catalyst ◽  
Catalyst Recovery ◽  
Catalytic Activities ◽  
Symmetric Structure ◽  
Organic Solvent Nanofiltration ◽  
Positive Effect

In this work, anchoring of cinchona derivatives to trifunctional cores (hub approach) was demonstrated to obtain size-enlarged organocatalysts. By modifying the cinchona skeleton in different positions, we prepared four C3-symmetric size-enlarged cinchona derivatives (hub-cinchonas), which were tested as organocatalysts and their catalytic activities were compared with the parent cinchona (hydroquinine) catalyst. We showed that in the hydroxyalkylation reaction of indole, hydroquinine provides good enantioselectivities (up to 73% ee), while the four new size-enlarged derivatives gave significantly lower values (up to 29% ee) in this reaction. Anchoring cinchonas to trifunctional cores was found to facilitate nanofiltration-supported catalyst recovery using PolarClean alternative solvent. The C3-symmetric size-enlarged organocatalysts were completely rejected by all the applied membranes, whereas the separation of hydroquinine was found to be insufficient using organic solvent nanofiltration. Furthermore, the asymmetric catalysis was successfully demonstrated in the case of Michael reaction of 1,3-diketones and trans-β-nitrostyrene using Hub3-cinchona (up to 96% ee) as a result of the positive effect of the C3-symmetric structure using a bulkier substrate. This means an increased selectivity of the catalyst in comparison to hydroquinine in the latter Michael reaction.

scholarly journals Synthesis of C3-Symmetric Cinchona-Based Organocatalysts and Their Applications in Asymmetric Michael and Friedel–Crafts Reactions

Symmetry ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 521
Author(s):  
Péter Kisszékelyi ◽  
Zsuzsanna Fehér ◽  
Sándor Nagy ◽  
Péter Bagi ◽  
Petra Kozma ◽  
...  
Keyword(s):  
Organic Solvent ◽  
Asymmetric Catalysis ◽  
Michael Reaction ◽  
Supported Catalyst ◽  
Catalyst Recovery ◽  
Catalytic Activities ◽  
Symmetric Structure ◽  
Organic Solvent Nanofiltration ◽  
Positive Effect ◽  
The Michael Reaction

In this work, anchoring of cinchona derivatives to trifunctional cores (hub approach) was demonstrated to obtain size-enlarged organocatalysts. By modifying the cinchona skeleton in different positions, we prepared four C3-symmetric size-enlarged cinchona derivatives (hub-cinchonas), which were tested as organocatalysts and their catalytic activities were compared with the parent cinchona (hydroquinine) catalyst. We showed that in the hydroxyalkylation reaction of indole, hydroquinine provides good enantioselectivities (up to 73% ee), while the four new size-enlarged derivatives resulted in significantly lower values (up to 29% ee) in this reaction. Anchoring cinchonas to trifunctional cores was found to facilitate nanofiltration-supported catalyst recovery using the PolarClean alternative solvent. The C3-symmetric size-enlarged organocatalysts were completely rejected by all the applied membranes, whereas the separation of hydroquinine was found to be insufficient when using organic solvent nanofiltration. Furthermore, the asymmetric catalysis was successfully demonstrated in the case of the Michael reaction of 1,3-diketones and trans-β-nitrostyrene using Hub3-cinchona (up to 96% ee) as a result of the positive effect of the C3-symmetric structure using a bulkier substrate. This equates to an increased selectivity of the catalyst in comparison to hydroquinine in the latter Michael reaction.

Organic Solvent Nanofiltration

2021 ◽  
pp. 889-932
Author(s):  
Torsten Brinkmann ◽  
Volkan Filiz
Keyword(s):  
Organic Solvent ◽  
Organic Solvent Nanofiltration

Fungal Cell Wall‐Graphene Oxide Microcomposite Membrane for Organic Solvent Nanofiltration

2021 ◽  
pp. 2100110
Author(s):  
Liyuan Zhang ◽  
Mengchen Zhang ◽  
Gongping Liu ◽  
Wanqin Jin ◽  
Xiaoyan Li
Keyword(s):  
Cell Wall ◽  
Graphene Oxide ◽  
Organic Solvent ◽  
Fungal Cell Wall ◽  
Fungal Cell ◽  
Organic Solvent Nanofiltration

Recent advances in nanomaterial-incorporated nanocomposite membranes for organic solvent nanofiltration

2021 ◽  
pp. 118657
Author(s):  
Chen Wang ◽  
Myoung Jun Park ◽  
Dong Han Seo ◽  
Enrico Drioli ◽  
Hideto Matsuyama ◽  
...  
Keyword(s):  
Organic Solvent ◽  
Nanocomposite Membranes ◽  
Recent Advances ◽  
Organic Solvent Nanofiltration
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