The Continuous Acid-Catalyzed Dehydration of Alcohols in Supercritical Fluids:  A New Approach to the Cleaner Synthesis of Acetals, Ketals, and Ethers with High Selectivity

1999 ◽  
Vol 121 (46) ◽  
pp. 10711-10718 ◽  
Author(s):  
William K. Gray ◽  
Fiona R. Smail ◽  
Martin G. Hitzler ◽  
Stephen K. Ross ◽  
Martyn Poliakoff
Keyword(s):  
Supercritical Fluids ◽  
High Selectivity ◽  
New Approach ◽  
Acid Catalyzed

scholarly journals Recent Development in Chemical Depolymerization of Lignin: A Review

2013 ◽  
Vol 2013 ◽  
pp. 1-9 ◽  
Author(s):  
Hai Wang ◽  
Melvin Tucker ◽  
Yun Ji
Keyword(s):  
High Pressure ◽  
Ionic Liquids ◽  
Supercritical Fluids ◽  
High Selectivity ◽  
Severe Reaction ◽  
Great Contribution ◽  
Reaction Conditions ◽  
Commercial Scale ◽  
High Pressure High Temperature ◽  
Acid Catalyzed

This article reviewed recent development of chemical depolymerization of lignins. There were five types of treatment discussed, including base-catalyzed, acid-catalyzed, metallic catalyzed, ionic liquids-assisted, and supercritical fluids-assisted lignin depolymerizations. The methods employed in this research were described, and the important results were marked. Generally, base-catalyzed and acid-catalyzed methods were straightforward, but the selectivity was low. The severe reaction conditions (high pressure, high temperature, and extreme pH) resulted in requirement of specially designed reactors, which led to high costs of facility and handling. Ionic liquids, and supercritical fluids-assisted lignin depolymerizations had high selectivity, but the high costs of ionic liquids recycling and supercritical fluid facility limited their applications on commercial scale biomass treatment. Metallic catalyzed depolymerization had great advantages because of its high selectivity to certain monomeric compounds and much milder reaction condition than base-catalyzed or acid-catalyzed depolymerizations. It would be a great contribution to lignin conversion if appropriate catalysts were synthesized.

Acid-Catalyzed Thermolytic Depolymerization of Polycarbonates: A New Approach to Dry-Developing Resist Materials

1987 ◽  
pp. 138-148 ◽  
Author(s):  
J. M. J. Fréchet ◽  
E. Eichler ◽  
M. Stanciulescu ◽  
T. Iizawa ◽  
F. Bouchard ◽  
...  
Keyword(s):  
New Approach ◽  
Acid Catalyzed

scholarly journals Models for Understanding Divergent Reactivity in Lewis Acid-Catalyzed Transformations of Carbonyls and Olefins

2019 ◽  
Author(s):  
Marc R. Becker ◽  
Jolene P. Reid ◽  
Katie Rykaczewski ◽  
Corinna Schindler
Keyword(s):  
Lewis Acid ◽  
Olefin Metathesis ◽  
Lewis Acids ◽  
Potential Energy Surfaces ◽  
High Selectivity ◽  
Linear Regression Models ◽  
Lewis Acid Catalysts ◽  
Carbon Carbon Bond ◽  
Acid Catalyzed ◽  
Energy Surfaces

<div>Carbonyl-ene, Prins and carbonyl-olefin metathesis reactions represent powerful strategies for carbon-carbon bond formation relying on Lewis acid catalysts. Although common Lewis acids are able to provide efficient activation, the reactions often proceed with low regio-, or chemoselectivity while high selectivity frequently requires the use of well-designed metal-ligand complexes. Here we demonstrate that simple Lewis acids including Me<sub>2</sub>AlCl, FeCl<sub>3</sub>, and SnCl<sub>4</sub> can show remarkable selectivity in dif-ferentiating between distinct transformations of carbonyl and olefin functional groups resulting in either carbonyl-ene or carbonyl-olefin metathesis products. Specifically, we report the development of predictive multivariate linear regression models that rely on kinetic and thermodynamic information obtained in DFT calculations to gain important insights into the complex potential energy surfaces (PES) of these competing reaction paths. The presented results further our understanding of Lewis acid reactivity and suggest that even simple Lewis acids have the potential to function as highly selective catalysts.</div>

scholarly journals A molecular approach to rationally constructing specific fluorogenic substrates for the detection of acetylcholinesterase activity in live cells, mice brains and tissues

2020 ◽  
Vol 11 (41) ◽  
pp. 11285-11292 ◽  
Author(s):  
Xiaofeng Wu ◽  
Jong Min An ◽  
Jizhen Shang ◽  
Eugene Huh ◽  
Sujie Qi ◽  
...  
Keyword(s):  
Mouse Brain ◽  
Ache Activity ◽  
Normal Mouse ◽  
High Selectivity ◽  
Acetylcholinesterase Activity ◽  
Live Cells ◽  
Molecular Approach ◽  
Fluorogenic Substrates ◽  
New Approach ◽  
Normal Mouse Brain

In this work, a new approach was developed for designing the representative P10 with high selectivity and sensitivity for imaging AChE activity in the cells and normal mouse brain.

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