Henry Constant of Water Adsorption on Functionalized Graphite: Importance of the Potential Models of Water and Functional Group

2018 ◽  
Vol 122 (42) ◽  
pp. 24171-24181 ◽  
Author(s):  
Yonghong Zeng ◽  
Hui Xu ◽  
Toshihide Horikawa ◽  
D. D. Do ◽  
D. Nicholson
Keyword(s):  
Water Adsorption ◽  
Functional Group ◽  
Henry Constant ◽  
Potential Models

scholarly journals Equilibrium Studies for Removal of Cadmium (II) Ions Removal from Water Using Activated Carbon Derived from Macadamia Intergrifolia Nutshell Waste Powder

2020 ◽  
pp. 185-197
Author(s):  
Amos Kamau ◽  
George Thiong’o ◽  
Beatrice Kakoi
Keyword(s):  
Aqueous Solution ◽  
Activated Carbon ◽  
Metal Ions ◽  
Water Adsorption ◽  
Functional Group ◽  
Low Cost ◽  
Langmuir Model ◽  
Equilibrium Studies ◽  
Freundlich Model ◽  
Favorable Reaction

Heavy metals have continued to be of great concern in research as major pollutants of water. Adsorption using low cost adsorbent is a low cost method of the removal heavy metal ions from aqueous solution. In this study activated carbon derived from macadamia intergrifolia nutshell powder was considered as an alternative low cost adsorbent for the removal of Cd(II) ions from aqueous solution. Various physicochemical parameters which included sorbent mass, and initial metal ions concentration isotherms using sorption models were determined. Results from the experiment indicated the optimum values for sorbent mass as 0.3 grams, and initial metal ions concentration as 8mg/l. Adsorption isotherms were found to fit well in Langmuir model (R2=0.9935), Javanovic model (R2 =0.9857) and Freundlich model (R2=0.9911). Additionally, for Langmuir model the value of separation factor (KL) was in the range of 0 to 1 indicating a favorable reaction. For Jovanovic model adsorption energy was found to be 1.00334 l/mg thus an indication of binding vibrations during Cd(II) ions adsorption.  FTIR spectrum revealed that the presence of O-H at νmax 3389 cm-1, COO- at νmax 2367 cm-1, C=0 at νmax 1593 cm-1,  C-O at νmax 1344 cm-1, P-O at νmax 1206 cm-1 and POO-H at νmax 1110cm-1 functional group in activated carbon enhanced Cd(II) ions removal.  The study revealed that activated carbon derived from macadamia intergrifolia nutshell can be used to remove Cd(II) ions from water. 

Semi-relativistic quark-antiquark potential models

1985 ◽  
Vol 10 (5) ◽  
pp. 475-522 ◽  
Author(s):  
J.L. Basdevant ◽  
S. Boukraa
Keyword(s):  
Potential Models

Metal-Free Photoinduced Hydroalkylation Cascade Enabled by an Electron-Donor-Acceptor Complex

2020 ◽  
Author(s):  
José Tiago Menezes Correia ◽  
Gustavo Piva da Silva ◽  
Camila Menezes Kisukuri ◽  
Elias André ◽  
Bruno Pires ◽  
...  
Keyword(s):  
Electron Donor ◽  
Functional Group ◽  
Photoexcited Electron ◽  
One Pot ◽  
Quaternary Centers ◽  
Metal Free ◽  
Acceptor Complex ◽  
Catalyst Free ◽  
Donor Acceptor ◽  
Radical Cascade

A metal- and catalyst-free photoinduced radical cascade hydroalkylation of 1,7-enynes has been disclosed. The process is triggered by a SET event involving a photoexcited electron-donor-aceptor complex between NHPI ester and Hantzsch ester, which decomposes to afford a tertiary radical that is readily trapped by the enyne. <a>The method provides an operationally simple, robust and step-economical approach to the construction of diversely functionalized dihydroquinolinones bearing quaternary-centers. A sequential one-pot hydroalkylation-isomerization approach is also allowed giving access to a family of quinolinones. A wide substrate scope and high functional group tolerance was observed in both approaches</a>.

Dual Nickel/Palladium-Catalyzed Reductive Cross-Coupling Reactions Between Two Phenol Derivatives

2020 ◽  
Author(s):  
Baojian Xiong ◽  
Yue Li ◽  
Yin Wei ◽  
Søren Kramer ◽  
Zhong Lian
Keyword(s):  
Functional Group ◽  
Low Cost ◽  
Cross Coupling ◽  
Coupling Reactions ◽  
Phenol Derivatives ◽  
Cross Coupling Reactions ◽  
Palladium Catalyzed ◽  
One Step ◽  
Aryl Tosylates ◽  
Low Sensitivity

Cross-coupling between substrates that can be easily derived from phenols is highly attractive due to the abundance and low cost of phenols. Here, we report a dual nickel/palladium-catalyzed reductive cross-coupling between aryl tosylates and aryl triflates; both substrates can be accessed in just one step from readily available phenols. The reaction has a broad functional group tolerance and substrate scope (>60 examples). Furthermore, it displays low sensitivity to steric effects demonstrated by the synthesis of a 2,2’disubstituted biaryl and a fully substituted aryl product. The widespread presence of phenols in natural products and pharmaceuticals allow for straightforward late-stage functionalization, illustrated with examples such as Ezetimibe and tyrosine. NMR spectroscopy and DFT calculations indicate that the nickel catalyst is responsible for activating the aryl triflate, while the palladium catalyst preferentially reacts with the aryl tosylate.

Effects of Wet Chemical Oxidation on Surface Functionalization and Morphology of Highly Oriented Pyrolytic Graphite

2020 ◽  
Author(s):  
Mikhail Trought ◽  
Isobel Wentworth ◽  
Timothy Leftwich ◽  
Kathryn Perrine
Keyword(s):  
Surface Functionalization ◽  
Functional Group ◽  
Pyrolytic Graphite ◽  
Surface Oxidation ◽  
Chemical Oxidation ◽  
Synthesis Methods ◽  
Acid Solutions ◽  
Highly Oriented Pyrolytic Graphite ◽  
Wet Chemical ◽  
Surface Morphologies

The knowledge of chemical functionalization for area selective deposition (ASD) is crucial for designing the next generation heterogeneous catalysis. Surface functionalization by oxidation was studied on the surface of highly oriented pyrolytic graphite (HOPG). The HOPG surface was exposed to with various concentrations of two different acids (HCl and HNO3). We show that exposure of the HOPG surface to the acid solutions produce primarily the same -OH functional group and also significant differences the surface topography. Mechanisms are suggested to explain these strikingly different surface morphologies after surface oxidation. This knowledge can be used to for ASD synthesis methods for future graphene-based technologies.

Catalytic Synthesis of Cyclic Guanidines via Hydrogen Atom Transfer and Radical-Polar Crossover

2020 ◽  
Author(s):  
Shunya Ohuchi ◽  
Hiroki Koyama ◽  
Hiroki Shigehisa
Keyword(s):  
Hydrogen Atom ◽  
Functional Group ◽  
Hydrogen Atom Transfer ◽  
Catalytic Synthesis ◽  
Membered Ring ◽  
Biologically Active ◽  
Atom Transfer ◽  
Powerful Method ◽  
Protective Groups ◽  
The Common

A catalytic synthesis of cyclic guanidines, which are found in many biologically active compounds and natu-ral products, was developed, wherein transition-metal hydrogen atom transfer and radical-polar crossover were employed. This mild and functional-group tolerant process enabled the cyclization of alkenyl guanidines bearing common protective groups, such as Cbz and Boc. This powerful method not only provided the common 5- and 6-membered rings but also an unusual 7-membered ring. The derivatization of the products afforded various heterocycles. We also investigated the se-lective cyclization of mono-protected or hetero-protected (TFA and Boc) alkenyl guanidines and their further derivatiza-tions.

Design, 22-step synthesis, and evaluation of highly potent D-ring modified and linker-equipped analogs of spongistatin 1

2018 ◽  
Author(s):  
James Leighton ◽  
Linda M. Suen ◽  
Makeda A. Tekle-Smith ◽  
Kevin S. Williamson ◽  
Joshua R. Infantine ◽  
...  
Keyword(s):  
Targeted Delivery ◽  
Functional Group ◽  
Human Cancer ◽  
Natural Sources ◽  
Spongistatin 1 ◽  
Human Cancer Cell Lines ◽  
Drug Conjugates ◽  
Attractive Candidate ◽  
Complex Fragment ◽  
Antibody Drug

With an average GI50 value against the NCI panel of 60 human cancer cell lines of 0.12 nM, spongistatin 1 is among the most potent anti-proliferative agents ever discovered rendering it an attractive candidate for development as a payload for antibody-drug conjugates and other targeted delivery approaches. It is unavailable from natural sources and its size and complex stereostructure render chemical synthesis highly time- and resource-intensive, however, and its development requires more efficient and step-economical synthetic access. Using novel and uniquely enabling direct complex fragment coupling alkallyl- and crotylsilylation reactions, we have developed a 22-step synthesis of a rationally designed D-ring modified analog of spongistatin 1 that is equipotent with the natural product, and have used that synthesis to establish that the C(15) acetate may be replaced with a linker functional group-bearing ester with only minimal reductions in potency.<br><div><br></div>

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