scholarly journals THE DETERMINATION OF CONSISTENT AND ACCURATE VALUES OF rHo(CaHbOd, a ≤ 16) OF ATOMIZATION OF THE AROMATIC COMPOUNDS BY THE SIMULTANEOUS USE OF THE EMPIRICALLY CORRECTED RESULTS AND UNCERTAINTIES OF SEVERAL QUANTUM MECHANICAL APPROACHES.

2021 ◽  
Author(s):  
Gregory Poskrebyshev
Keyword(s):  
Confidence Interval ◽  
Aromatic Compounds ◽  
Standard Errors ◽  
Quantum Mechanical ◽  
Linear Scaling ◽  
Simultaneous Use ◽  
Related Compounds

The empirical linear scaling dependencies between the literature (rHo(Xn,TAB)) and the calculated (rHo((Xn)i,CALC)) values of atomization of 31 reference aromatic and related compounds (T=298.15K), as well as their standard errors ((SE4)i(4)i, Stand.Dev.), are determined for the different quantum mechanical (QMi) approaches. These dependencies are compared and used for the determination of the values of rHo((Xn)i,CORRE)±3(SE4)i of atomization reactions of considered not reference aromatic compounds, as well as for the determination of their values of fHo((Xn)i,CORRE)±3(SE4)i. The values of fHo((Xn)i,CORRE)MEAN±3SEYE (≥99.4% confidence interval), determined using the intersections of the 3(SE4)i intervals, are consistent with all QMi approaches and their literature values. The M06-2X/6-311++G(d,p), M08HX/6-311++G(d,p) and wB97XD/6-311++G(d,p) approaches are recommended for the achievement of accuracy (SEYE)≤3.8 kJ/mol of the calculated values of fHo((Xn)i,CORRE)MEAN. The effects of the number of O-H groups, size and multiplicity of compounds on values of error, also studied in this work, demonstrate the limitations of using of several scaled dependencies.

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>

scholarly journals Accuracy of Doppler Determinations of Station Positions

1972 ◽  
Vol 48 ◽  
pp. 101-103
Author(s):  
R. J. Anderle
Keyword(s):  
Elevation Angle ◽  
High Elevation ◽  
Time Of Day ◽  
Satellite Observations ◽  
Standard Errors ◽  
Lower Elevation ◽  
Self Consistent

Locations of Doppler satellite observing stations have been revised to obtain a set which is more self-consistent and more consistent with the CIO pole. Residuals of satellite observations for 1970 have been analyzed using the new coordinates to determine mean and standard errors for five days of observations of latitude versus station, time of day, and elevation angle. The accuracy of the determination of latitude is about 4 meters at moderate and high elevation angles. But since more satellite passes occur at lower elevation angles, the accuracy of determination of a component of position based on five days of observation of one satellite is only about 2 meters.

Liquid Chromatographic Determination of Amiodarone Hydrochloride and Related Compounds in Raw Materials and Tablets

1994 ◽  
Vol 77 (6) ◽  
pp. 1447-1453 ◽  
Author(s):  
Pauline M Lacrok ◽  
Norman M Curran ◽  
Wing-Wah Sy ◽  
Dennis K J Goreck ◽  
Pierre Thibault ◽  
...  
Keyword(s):  
Raw Materials ◽  
Chromatographic Determination ◽  
Raw Material ◽  
Liquid Chromatographic Method ◽  
Limit Of Quantitation ◽  
Liquid Chromatographic Determination ◽  
Liquid Chromatographic ◽  
Amiodarone Hydrochloride ◽  
Related Compounds

Abstract A liquid chromatographic method for the determination of amiodarone hydrochloride and 10 related compounds in drug raw material and for assay of drug in tablets was developed. The method specifies a 3 jxm Hypersil nitrile column (150 × 4.6 mm), a mobile phase of 1 + 1 acetonitrile–ammonium acetate buffer (0.1 M adjusted to pH 6.0 with 0.1 M acetic acid), a flow rate of 1 mL/min, and detection at 240 nm. The lower limit of quantitation of the related compounds is 0.02% or less. Drug contents in 2 raw material samples were 100.1 and 99.9% and ranged from 98.2 to 99.4% in 3 tablet formulations. Impurity levels in 2 samples of raw material from different manufacturers were ca 0.4%. The presence of 3 of the known related compounds in these samples was confirmed by liquid chromatographymass spectrometry. The method applied to raw materials was evaluated by a second laboratory and found to be satisfactory.

scholarly journals A CHEMICAL METHOD FOR THE DETERMINATION OF PTEROYLGLUTAMIC ACID AND RELATED COMPOUNDS

1947 ◽  
Vol 168 (2) ◽  
pp. 705-710
Author(s):  
B.L. Hutchings ◽  
E.L.R. Stokstad ◽  
J.H. Boothe ◽  
J.H. Mowat ◽  
C.W. Waller ◽  
...  
Keyword(s):  
Chemical Method ◽  
Pteroylglutamic Acid ◽  
Related Compounds
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