Analytical utilization of UV spectra of aromatic compounds with oxygen electron donating and electron accepting groups

1974 ◽  
Vol 39 (9) ◽  
pp. 2449-2462 ◽  
Author(s):  
D. Walterová ◽  
L. Hruban ◽  
F. Šantavý
Keyword(s):  
Aromatic Compounds ◽  
Uv Spectra

scholarly journals COD, TOC determination using UV spectrophotometry and its application to monitor the potassium hydrogen phthalate degradation by H2O2-HCO3– oxidation system

2021 ◽  
Vol 63 (11) ◽  
pp. 14-18
Author(s):  
Thi Bich Viet Nguyen ◽  
◽  
Bich Ngan Nguyen ◽  
Thi Theu Tran ◽  
Thi Diu Vu ◽  
...  
Keyword(s):  
Aromatic Compounds ◽  
Degradation Products ◽  
Uv Spectra ◽  
Uv Spectrophotometry ◽  
Potassium Hydrogen Phthalate ◽  
Hydrogen Phthalate ◽  
Toc Removal ◽  
Factors Influencing ◽  
Potassium Hydrogen ◽  
Oxidation System

In this study, the COD and TOC in H2O2-HCO3– oxidation system containing potassium hydrogen phthalate were determined by UV spectrophotometry (260-310 nm). The pH and H2O2 concentrations were investigated as factors influencing the absorbance measurements. The obtained standard curves were Abs = (3.10±0.04)x103xCOD - (0.015±0.003) (R2=0.9996) with LOD of 5.1 mg O2/l and LOQ of 13.6 mg O2/l, and Abs = (0.008±0.0001)xTOC - (0.015±0.003) (R2=0.9996) with LOD of 1.6 mg/l and LOQ of 5.4 mg/l. The method was applied to monitor the degradation of potassium hydrogen phthalate by the H2O2-HCO3– oxidation system. The results revealed that the COD and TOC removal efficiencies reached ~85% after 90 minutes of UVC irradiation. The UV spectra and HPLC chromatographs showed that no aromatic compounds were obtained in the degradation products.

1679 Fatty acid profile, sensory traits, and aromatic compounds of chops from lambs fed ground woody plants as roughage in feedlot finishing diets

2016 ◽  
Vol 94 (suppl_5) ◽  
pp. 818-818
Author(s):  
K. R. Wall ◽  
C. R. Kerth ◽  
T. R. Whitney ◽  
S. B. Smith ◽  
J. L. Glasscock ◽  
...  
Keyword(s):  
Fatty Acid ◽  
Fatty Acid Profile ◽  
Aromatic Compounds ◽  
Woody Plants ◽  
Finishing Diets

Tandem Mass Spectrometric Evaluation of Core Structures of Aromatic Compounds after Catalytic Deoxygenation

2017 ◽  
Author(s):  
Xueming Dong
Keyword(s):  
Aromatic Compounds ◽  
Supported Catalyst ◽  
Mass Spectrometric ◽  
Spectrometric Method ◽  
Mass Spectrometric Method ◽  
Aromatic Rings ◽  
Tandem Mass Spectrometric ◽  
Catalytic Deoxygenation ◽  
Oxygen Atoms

Catalytic deoxygenation of coal enhances the stability and combustion performance of coal-derived liquids. However, determination of the selectivity of removal of oxygen atoms incorporated in or residing outside of aromatic rings is challenging. This limits the ability to evaluate the success of catalytic deoxygenation processes. A mass spectrometric method, in-source collision-activated dissociation (ISCAD), combined with high resolution product ion detection, is demonstrated to allow the determination of whether the oxygen atoms in aromatic compounds reside outside of aromatic rings or are part of the aromatic system, because alkyl chains can be removed from aromatic cores via ISCAD. Application of this method for the analysis of a subbituminous coal treated using a supported catalyst revealed that the catalytic treatment reduced the number of oxygen-containing heteroaromatic rings but not the number of oxygen atoms residing outside the aromatic rings.<br>

Tandem Mass Spectrometric Evaluation of Core Structures of Aromatic Compounds after Catalytic Deoxygenation

2017 ◽  
Author(s):  
Xueming Dong
Keyword(s):  
Aromatic Compounds ◽  
Supported Catalyst ◽  
Mass Spectrometric ◽  
Spectrometric Method ◽  
Mass Spectrometric Method ◽  
Aromatic Rings ◽  
Tandem Mass Spectrometric ◽  
Catalytic Deoxygenation ◽  
Oxygen Atoms

Catalytic deoxygenation of coal enhances the stability and combustion performance of coal-derived liquids. However, determination of the selectivity of removal of oxygen atoms incorporated in or residing outside of aromatic rings is challenging. This limits the ability to evaluate the success of catalytic deoxygenation processes. A mass spectrometric method, in-source collision-activated dissociation (ISCAD), combined with high resolution product ion detection, is demonstrated to allow the determination of whether the oxygen atoms in aromatic compounds reside outside of aromatic rings or are part of the aromatic system, because alkyl chains can be removed from aromatic cores via ISCAD. Application of this method for the analysis of a subbituminous coal treated using a supported catalyst revealed that the catalytic treatment reduced the number of oxygen-containing heteroaromatic rings but not the number of oxygen atoms residing outside the aromatic rings.<br>

Photocatalytic Alkylation of Pyrroles and Indoles with α-Diazo Esters

2019 ◽  
Author(s):  
Łukasz Ciszewski ◽  
Jakub Durka ◽  
Dorota Gryko
Keyword(s):  
Aromatic Compounds ◽  
Reaction Pathway ◽  
Alkylating Agents ◽  
Catalytic Amount ◽  
Radical Formation ◽  
Reaction Selectivity ◽  
Diazo Esters ◽  
Electron Withdrawing Substituents

This article describes direct photoalkylation of electron-rich aromatic compounds with diazo compoiunds. C-2 alkylated indoles and pyrroles are obtained with good yields even though the photocatalyst (Ru(bpy)3Cl2) loading is as low as 0.075 mol %. For substrates bearing electron-withdrawing substituents the addition of a catalytic amount of N,N-dimethyl-4-methoxyaniline is required. Both EWG-EWG and EWG-EDG substituted diazo esters are suitable as alkylating agents. The reaction selectivity and mechanistic experiments suggest that carbenes/carbenoid intermediates are not involved in the reaction pathway, instead radical formation is proposed.

A Simplified Protocol for the ortho-Deuteration of Acidic Aromatic Compounds in D2O

2019 ◽  
Author(s):  
Alyssa Garreau ◽  
Hanyang Zhou ◽  
Michael Young
Keyword(s):  
Carboxylic Acid ◽  
Aromatic Compounds ◽  
Large Scale ◽  
Simplified Approach ◽  
Directing Group ◽  
Large Scale Synthesis

<div>Methods to catalytically introduce deuterium in synthetically useful yields ortho to a carboxylic acid directing group on arenes typically requires D2 or CD3CO2D, which makes using these approaches cost prohibitive for large scale synthesis (equipment and reagent costs respectively). Herein we present a simplified approach using catalytic RhIII and D2O as deuterium source, and show its application to H/D exchange on various acidic substrates.</div>

A Simplified Protocol for the ortho-Deuteration of Acidic Aromatic Compounds in D2O

2019 ◽  
Author(s):  
Alyssa Garreau ◽  
Hanyang Zhou ◽  
Michael Young
Keyword(s):  
Carboxylic Acid ◽  
Aromatic Compounds ◽  
Large Scale ◽  
Simplified Approach ◽  
Directing Group ◽  
Large Scale Synthesis

<div>Methods to catalytically introduce deuterium in synthetically useful yields ortho to a carboxylic acid directing group on arenes typically requires D2 or CD3CO2D, which makes using these approaches cost prohibitive for large scale synthesis (equipment and reagent costs respectively). Herein we present a simplified approach using catalytic RhIII and D2O as deuterium source, and show its application to H/D exchange on various acidic substrates.</div>

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