New aspects of relationship between the enthalpies of fusion of aromatic compounds at the melting temperature and the enthalpies of solution in benzene at 298.15 K. Part II

2018 ◽  
Vol 120 ◽  
pp. 21-26 ◽  
Author(s):  
Mikhail I. Yagofarov ◽  
Ruslan N. Nagrimanov ◽  
Marat A. Ziganshin ◽  
Boris N. Solomonov
Keyword(s):  
Melting Temperature ◽  
Aromatic Compounds ◽  
Enthalpies Of Solution

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.

Compliance with Amended General Chapter USPMelting Range or Temperature

2019 ◽  
Author(s):  
Samuele Giani ◽  
Naomi M. Towers
Keyword(s):  
Melting Temperature ◽  
Reference Standards ◽  
Melting Range ◽  
Primary Reference ◽  
General Chapter ◽  
Regulation Compliance

Laboratories measuring melting temperature according to USP<741> Melting Range or Temperature, must comply with the amended calibration and adjustment requirements described in this regulation. Compliance is ensured by adjusting the instrument with secondary reference standards, traceable to USP, followed by verification of accuracy using USP primary reference standards.

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