Highly active metal–acid bifunctional catalyst system for hydrogenolysis of glycerol under mild reaction conditions

Tetrabutylammonium hydroxide with methanol as an additive was found to be a highly active catalyst for the cleavage of 4-aryl-2-methyl-3-butyn-2-ols. The reaction was performed at 55–75 °C and gave terminal arylacetylenes in good to excellent yields within several minutes. Compared with the usual reaction conditions (normally >110 °C, several hours), this novel catalyst system can dramatically decrease the reaction time under much milder conditions.

Download Full-text

Urea-Catalyzed Functionalization of Unactivated C–H Bonds

10.26434/chemrxiv.11886789.v1 ◽

2020 ◽

Cited By ~ 2

Author(s):

Alex L. Bagdasarian ◽

Stasik Popov ◽

Benjamin Wigman ◽

Wenjing Wei ◽

woojin lee ◽

...

Keyword(s):

Hydrogen Bonding ◽

Organic Synthesis ◽

High Energy ◽

Acid Catalysts ◽

Potential Utility ◽

New Paradigm ◽

Lewis Acid Catalysts ◽

Reaction Conditions ◽

Highly Active ◽

Acidic Nature

Herein we report the 3,5bistrifluoromethylphenyl urea-catalyzed functionalization of unactivated C–H bonds. In this system, the urea catalyst mediates the formation of high-energy vinyl carbocations that undergo facile C–H insertion and Friedel–Crafts reactions. We introduce a new paradigm for these privileged scaffolds where the combination of hydrogen bonding motifs and strong bases affords highly active Lewis acid catalysts capable of ionizing strong C–O bonds. Despite the highly Lewis acidic nature of these catalysts that enables triflate abstraction from sp2 carbons, these newly found reaction conditions allow for the formation of heterocycles and tolerate highly Lewis basic heteroaromatic substrates. This strategy showcases the potential utility of dicoordinated vinyl carbocations in organic synthesis.

Download Full-text

Urea-Catalyzed Functionalization of Unactivated C–H Bonds

10.26434/chemrxiv.11886789 ◽

2020 ◽

Author(s):

Alex L. Bagdasarian ◽

Stasik Popov ◽

Benjamin Wigman ◽

Wenjing Wei ◽

woojin lee ◽

...

Keyword(s):

Hydrogen Bonding ◽

Organic Synthesis ◽

High Energy ◽

Acid Catalysts ◽

Potential Utility ◽

New Paradigm ◽

Lewis Acid Catalysts ◽

Reaction Conditions ◽

Highly Active ◽

Acidic Nature

Herein we report the 3,5bistrifluoromethylphenyl urea-catalyzed functionalization of unactivated C–H bonds. In this system, the urea catalyst mediates the formation of high-energy vinyl carbocations that undergo facile C–H insertion and Friedel–Crafts reactions. We introduce a new paradigm for these privileged scaffolds where the combination of hydrogen bonding motifs and strong bases affords highly active Lewis acid catalysts capable of ionizing strong C–O bonds. Despite the highly Lewis acidic nature of these catalysts that enables triflate abstraction from sp2 carbons, these newly found reaction conditions allow for the formation of heterocycles and tolerate highly Lewis basic heteroaromatic substrates. This strategy showcases the potential utility of dicoordinated vinyl carbocations in organic synthesis.

Download Full-text

Chemical reduction of chlorpyrifos driven by flavin mononucleotide functionalized titanium (IV) dioxide

Physical Sciences Reviews ◽

10.1515/psr-2020-0007 ◽

2020 ◽

Vol 5 (11) ◽

Author(s):

Stephanie Santos Díaz ◽

Hazim Al-Zubaidi ◽

Amir C. Ross-Obare ◽

Sherine O. Obare

Keyword(s):

Functional Groups ◽

Organic Contaminants ◽

Chemical Reduction ◽

Flavin Mononucleotide ◽

Reaction Conditions ◽

Organophosphate Compounds ◽

Biological Molecule ◽

Highly Active ◽

New Directions ◽

Detrimental Impact

AbstractFor many decades, organohalide and organophosphate compounds have shown significant detrimental impact on the environment. Consequently, strategies for their remediation continue to be an area of emerging need. The reduction of the chlorpyrifos pesticide, a molecule that bears both organohalide and organophosphate functional groups, is an important area of investigation due to it toxic nature. In this report, we demonstrate the effectiveness of the biological molecule, flavin mononucleotide (FMN) toward chemically reducing chlorpyrifos. The FMN was found to be highly active when anchored to nanocrystalline TiO2 surfaces. The results show new directions toward the remediation of organic contaminants under mild reaction conditions.

Download Full-text

Rapid synthesis of a PtRu nano-sponge with different surface compositions and performance evaluation for methanol electrooxidation

Nanoscale ◽

10.1039/c5nr00639b ◽

2015 ◽

Vol 7 (21) ◽

pp. 9467-9471 ◽

Cited By ~ 56

Author(s):

Meiling Xiao ◽

Ligang Feng ◽

Jianbing Zhu ◽

Changpeng Liu ◽

Wei Xing

Keyword(s):

Performance Evaluation ◽

Electronic Effect ◽

Catalyst System ◽

Methanol Electrooxidation ◽

Co Poisoning ◽

Rapid Synthesis ◽

Highly Active ◽

Electro Oxidation ◽

Pt Utilization ◽

And Performance

A rapid strategy to synthesize a highly active PtRu alloy nano-sponge catalyst system for methanol electro-oxidation is presented. The greatly increased Pt utilization, anti-CO poisoning ability and electronic effect result from the porous nano-sponge structure.

Download Full-text

Soluble porous carbon cage-encapsulated highly active metal nanoparticle catalysts

Journal of Materials Chemistry A ◽

10.1039/d1ta01352a ◽

2021 ◽

Author(s):

Hangyu Liu ◽

Liyu Chen ◽

Chun-Chao Hou ◽

Yong-Sheng Wei ◽

Qiang Xu

Keyword(s):

Porous Carbon ◽

Metal Organic Framework ◽

Metal Nanoparticle ◽

Hydrogen Peroxide Decomposition ◽

Carbon Cage ◽

Nanoparticle Catalysts ◽

Highly Active ◽

Active Metal ◽

Peroxide Decomposition ◽

Metal Organic

Metal nanoparticles are encapsulated within soluble porous carbon cages by a silica-shelled metal–organic framework pyrolysis approach. The catalyst shows high catalytic activities for hydrogen peroxide decomposition and ammonia borane hydrolysis.

Download Full-text

A nanostructured bifunctional acid–base catalyst resin formed by lyotropic liquid crystal monomers

Canadian Journal of Chemistry ◽

10.1139/cjc-2019-0408 ◽

2020 ◽

Vol 98 (7) ◽

pp. 332-336

Author(s):

Gregory E. Dwulet ◽

Benjamin J. Coscia ◽

Michael R. Shirts ◽

Douglas L. Gin

Keyword(s):

Liquid Crystal ◽

Self Assembly ◽

Polymeric Materials ◽

Dimethyl Acetal ◽

Bifunctional Catalyst ◽

Lyotropic Liquid Crystal ◽

Solid Catalyst ◽

Test Reaction ◽

Highly Active ◽

Nitroaldol Reaction

An ordered, nanoporous polymer resin was prepared from the self-assembly of lyotropic liquid crystal monomers and employed as a heterogeneous, bifunctional catalyst. This material contains antagonistic acid and base sites in the periodic nanopores and efficiently catalyzes a model tandem reaction (i.e., the deacetalization–nitroaldol reaction between benzaldehyde dimethyl acetal and nitromethane to yield β-nitrostyrene) with excellent product selectivity. This lyotropic liquid crystal-based solid catalyst represents one of the few examples of polymeric tandem catalysts synthesized by a “bottom-up” strategy that imparts control over the stoichiometry of acidic and basic monomers and is the only reported example of a lyotropic liquid crystal-based polymer that contains mutually incompatible catalytic groups. Furthermore, this heterogeneous catalyst is highly active, exhibiting a turnover frequency for this tandem test reaction that exceeds other reported catalytic polymeric materials.

Download Full-text