Simultaneous oxidation and analysis of TOC-TN-TP in one pot reactor

Chemosphere ◽  
2021 ◽  
pp. 133336
Author(s):  
Donghun Shin ◽  
Jong-Gook Kim ◽  
Hye-Bin Kim ◽  
Kitae Baek
Keyword(s):  
One Pot ◽  
Simultaneous Oxidation

scholarly journals Arsenic removal from water using a one-pot synthesized low-cost mesoporous Fe-Mn-modified biosorbent

2019 ◽  
Vol 84 (3) ◽  
pp. 327-342 ◽  
Author(s):  
Jasmina Nikic ◽  
Malcolm Watson ◽  
Aleksandra Tubic ◽  
Marijana Kragulj-Isakovski ◽  
Snezana Maletic ◽  
...  
Keyword(s):  
Arsenic Removal ◽  
Low Cost ◽  
Drinking Water Treatment ◽  
Arsenic Species ◽  
Point Of Zero Charge ◽  
Adsorption Model ◽  
One Pot ◽  
Adsorption Sites ◽  
Simultaneous Oxidation ◽  
Intra Particle Diffusion

This paper investigates the removal of arsenic from water using an environmentally friendly modified biosorbent, chitosan coated with Fe?Mn binary oxide (Chit-FeMn), simply prepared with an one-pot low-cost procedure by simultaneous oxidation and coprecipitation. The sorbent was characterized by SEM, EDS, XRD, FTIR, BET specific surface area, and point of zero charge (pHpzc) measurements. The kinetic data fitted a pseudo-second order model for both As(III) and As(V), suggesting chemical adsorption on the sorbent surface and that intra-particle diffusion is not the only rate-limiting step during adsorption. The adsorption isotherms were best fit to the Freundlich model, and the non-monolayer adsorption model for arsenic on Chit-FeMn is therefore proposed. Below pH 9, the effect of pH on As(III) and As(V) removal by Chit-FeMn was insignificant, with As removals remaining above 85 %. Cl- and NO3 - had negligible influences on As(III) and As(V) removal, whereas PO4 3-, SiO3 2-, CO3 2- and SO4 2- were observed to compete with arsenic species for adsorption sites. The adsorbent was successfully applied to remove arsenic from real arsenic contaminated groundwater samples to below 10 ?g L-1 suggesting that Chit-FeMn is a promising candidate for the low cost removal of both As(V) and As(III) during drinking water treatment.

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>.

One-Pot Synthesis and Conformational Analysis of 6-Membered Cyclic Iodonium Salts

2020 ◽  
Author(s):  
Lucien Caspers ◽  
Julian Spils ◽  
Mattis Damrath ◽  
Enno Lork ◽  
Boris Nachtsheim
Keyword(s):  
Conformational Analysis ◽  
Bronsted Acids ◽  
One Pot ◽  
Benzyl Alcohols ◽  
Iodonium Salts ◽  
Efficient Approach ◽  
One Pot Synthesis ◽  
Diaryliodonium Salts

In this article we describe an efficient approach for the synthesis of cyclic diaryliodonium salts. The method is based on benzyl alcohols as starting materials and consists of an Friedel-Crafts-arylation/oxidation sequence. Besides a deep optimization, particluar focusing on the choice and ratios of the utilized Bronsted-acids and oxidants, we explore the substrate scope of this transformation. We also discuss an interesting isomerism of cyclic iodonium salts substituted with aliphatic substituents at the bridge head carbon. <br>

Metal-, and Organocatalyst-Free One-Pot Assembly of Chiral Aza-Tricyclic Molecules: Creating Six Contiguous Stereocenters from 2-D-Structures and an Amino Acid

2020 ◽  
Author(s):  
Dung Do
Keyword(s):  
Amino Acid ◽  
Chemical Space ◽  
Structural Diversity ◽  
Therapeutic Agents ◽  
Chiral Molecules ◽  
One Pot ◽  
Complex Molecules ◽  
Chiral Catalyst ◽  
Chiral Complex ◽  
Free Process

<p>Chiral molecules with their defined 3-D structures are of paramount importance for the study of chemical biology and drug discovery. Having rich structural diversity and unique stereoisomerism, chiral molecules offer a large chemical space that can be explored for the design of new therapeutic agents.<sup>1</sup> Practically, chiral architectures are usually prepared from organometallic and organocatalytic processes where a transition metal or an organocatalyst is tailor-made for desired reactions. As a result, developing a method that enables rapid assembly of chiral complex molecules under metal- and organocatalyst-free condition represents a daunting challenge. Here we developed a straightforward route to create a chiral 3-D structure from 2-D structures and an amino acid without any chiral catalyst. The center of this research is the design of a <a>special chiral spiroimidazolidinone cyclohexadienone intermediate</a>, a merger of a chiral reactive substrate with multiple nucleophillic/electrophillic sites and a transient organocatalyst. <a>This unique substrate-catalyst (“subcatalyst”) dual role of the intermediate enhances </a><a>the coordinational proximity of the chiral substrate and catalyst</a> in the key Aza-Michael/Michael cascade resulting in a substantial steric discrimination and an excellent overall diastereoselectivity. Whereas the “subcatalyst” (hidden catalyst) is not present in the reaction’s initial components, which renders a chiral catalyst-free process, it is strategically produced to promote sequential self-catalyzed reactions. The success of this methodology will pave the way for many efficient preparations of chiral complex molecules and aid for the quest to create next generation of therapeutic agents.</p>

Room Temperature Alkali Metal Reduction of Carbon Dioxide

2020 ◽  
Author(s):  
Lucas A. Freeman ◽  
Akachukwu D. Obi ◽  
Haleigh R. Machost ◽  
Andrew Molino ◽  
Asa W. Nichols ◽  
...  
Keyword(s):  
Alkali Metal ◽  
Alkali Metals ◽  
Room Temperature ◽  
Chemical Reduction ◽  
Bond Cleavage ◽  
Open Shell ◽  
Metal Reduction ◽  
One Pot ◽  
Earth Abundant ◽  
Electron Reduction

The reduction of the relatively inert carbon–oxygen bonds of CO<sub>2</sub> to access useful CO<sub>2</sub>-derived organic products is one of the most important fundamental challenges in synthetic chemistry. Facilitating this bond-cleavage using earth-abundant, non-toxic main group elements (MGEs) is especially arduous because of the difficulty in achieving strong inner-sphere interactions between CO<sub>2</sub> and the MGE. Herein we report the first successful chemical reduction of CO<sub>2</sub> at room temperature by alkali metals, promoted by a cyclic(alkyl)(amino) carbene (CAAC). One-electron reduction of CAAC-CO<sub>2</sub> adduct (<b>1</b>) with lithium, sodium or potassium metal yields stable monoanionic radicals clusters [M(CAAC–CO<sub>2</sub>)]<sub>n</sub>(M = Li, Na, K, <b> 2</b>-<b>4</b>) and two-electron alkali metal reduction affords open-shell, dianionic clusters of the general formula [M<sub>2</sub>(CAAC–CO<sub>2</sub>)]<sub>n </sub>(<b>5</b>-<b>8</b>). It is notable that these crystalline clusters of reduced CO<sub>2</sub> may also be isolated via the “one-pot” reaction of free CO<sub>2</sub> with free CAAC followed by the addition of alkali metals – a reductive process which does not occur in the absence of carbene. Each of the products <b>2</b>-<b>8</b> were investigated using a combination of experimental and theoretical methods.<br>

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