scholarly journals Correction to Computational Investigations for Undergraduate Organic Chemistry: Modeling a TLC Exercise to Investigate Molecular Structure and Intermolecular Forces

2001 ◽  
Vol 78 (9) ◽  
pp. 1183
Author(s):  
Rita K. Hessley
1951 ◽  
Vol 24 (2) ◽  
pp. 336-343
Author(s):  
B. A. Dogadkin ◽  
G. M. Bartenev ◽  
M. M. Reznikovskii˘

Abstract 1. The molecular mechanism of the relaxation of deformation of high-elastic polymers has been studied. 2. It is shown that the slow relaxation, which is typical of high-elastic polymers, may be best explained as a restoration process, which either partial or complete (depending on the degree of development of side chains in the molecular structure formed by the main valence chains) of the balanced configurations of the molecular chains. 3. It is shown that the rate of the relaxation process in this case is determined by the molecular activity of the particular polymer. 4. An approximate equation for the kinetics of high-elastic deformation which expresses qualitatively the mechanical properties of high-elastic polymers is proposed. 5. Hypotheses concerning the relation between the time of relaxation and the unbalanced stress are advanced. Equation (2) is derived as characteristic of this relation. 6. It is shown that the joint application of Equations (1) and (2) makes it possible to describe qualitatively the relaxation of stress at constant deformation.


1970 ◽  
Vol 24 (6) ◽  
pp. 591-595 ◽  
Author(s):  
D. W. Mayo ◽  
Stanley K. Freeman

The use of Raman spectroscopy in the determination of complex molecular structure is discussed. For 12 cedranes, five of the seven most intense bands observed between 900 and 500 cm−1 appear in a series of relatively narrow wavenumber ranges, and these are correctable with the cedrane skeleton. A band of variable intensity at ca. 320 cm−1, characterized by a ρ value of 0.2–0.4, may be included in the correlation pattern.


2019 ◽  
Author(s):  
Guy Lamoureux ◽  
J. F. Ogilvie

The importance of hybrid atomic orbitals, in both general and organic chemistry, is reviewed. Every contemporary textbook of organic chemistry introduces the sp3, sp2, sp model, but the suitability of these hybrid orbitals for use in the teaching of molecular structure has been increasingly questioned. Based on a critical survey of the literature, we submit seven practical criteria that deprecate the use of hybrid orbitals in a pedagogical context. We suggest how the teaching of organic chemistry without hybrid orbitals will provide students with an enhanced education.


2021 ◽  
Author(s):  
Vai Yee Hon ◽  
Ismail Mohd Saaid ◽  
Ching Hsia Ivy Chai ◽  
Noor 'Aliaa M. Fauzi ◽  
Estelle Deguillard ◽  
...  

Abstract Advances in digital technologies have the potential to enhance model predictive capability and redefine its boundaries at various scale. Digital oil with accurate representation of atomistic components is a powerful tool to analyze both macroscopic properties and microscopic phenomena of crude oil under any thermodynamic conditions. Digital oil model presented in this paper is the key input in molecular chemistry modeling for designing chemical enhanced oil recovery formulation. Hence, it is constructed based on a fit-for purpose strategy focusing in oil components that have large contribution to microemulsion stability. Complete crude oil composition could comprise over 100,000 components. Lengthy simulation time is required to simulate all crude oil components which is impratical, despite the challenges to identify all crude oil components experimentally. Therefore, we established a practical experimental strategy to identify key crude oil components and constructed the digital oil model based on surrogate components. The surrogate components are representative molecules of the volatiles, saturates, aromatics and resins. Two-dimensional digital oil model, with aromaticity on one axis, and the size of the molecules on the other axis was constructed. We developed algorithm to integrate nuclear magnetic resonance response with architecture of the molecular structure. A group contribution method was implemented to ensure reliable representation of the molecular structure. We constructed the digital oil models for a field in Malaysia Basin. We validated the physical properties of the digital oil model with properties measured from experiment, predicted from molecular dynamics simulation and calculated from quantitative property-property relationship method. Good agreement was obtained from the validation, with less than 5% and 13% variance in crude density and Equivalent Alkane Carbon Number respectively, indicating that the molecular characteristic of the digital oil model was captured correctly. We adopted the digital oil model in molecular chemistry modeling to gain insights into microemulsion formation in chemical enhanced oil recovery formulation design. Digital oil is a robust tool to make predictions when information cannot be extracted from experimental data alone. It can be extended for engineering applications involving processing, safety, hazard, and environmental considerations.


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