scholarly journals Prediction of physico-chemical properties for polycyclic aromatic hydrocarbons based on electronic characteristics of molecules

2019 ◽  
Vol 59 (7) ◽  
pp. 116-121
Author(s):  
Mikhail Yu. Dolomatov ◽  
◽  
Natalia H. Paymurzina ◽  
Ella A. Kovaleva ◽  
◽  
...  

QSPR models have been developed to predict of polycyclic aromatic hydrocarbons (PAHs) based on quantum chemical and integral spectroscopic descriptors. The first ionization potentials calculated from the energies of the highest occupied molecular orbital (HOMO), relative autocorrelation empirical parameters and the total number of electrons of non-ionized molecules were used as quantum chemical descriptors. Ionization potentials, electron affinities, boiling points, molecular masses, saturation vapor pressure of PAHs were studied as physical-chemical properties. Ionization potentials and electron affinities (IPs and EAs) are calculated by the use of density functional theory (DFT). Relative empirical autocorrelation parameters µ were calculated from the spectra of PAH molecules experimentally obtained and taken from the databases. The predictive power of resulting model is demonstrated by testing it on unseen data that were not used during model generation. Coefficients of determination for all dependencies considered in this paper are not less than 0.95. To assess the reliability for coefficients of determination, their mean errors were calculated. In this paper, we compared theoretical (experimental) and model-calculated values. Relative errors were estimated: for the electron donating ability of PAHs is 1.11% (for IP) and 0.86% (for EA); at about 3.1% for boiling points; not more than 0.51% for molar mass, for saturated vapor pressure, the error is more significant, which is apparently due to the difficulties of determining this value. The obtained models make it possible to estimate physical and chemical properties with sufficient accuracy for practical applications. The research results can be practically used in petrochemistry, carbon chemistry, organic chemistry, for prediction of physical and chemical properties PAH molecules.

1989 ◽  
Vol 135 ◽  
pp. 155-171
Author(s):  
S. Leach

A review is presented of some physical and chemical properties of polycyclic aromatic hydrocarbons (PAHs) that are relevant for interpreting various aspects of observations and speculations on PAHs in the interstellar medium. The subjects discussed are: the stability and reactivity of neutral and ionic PAHs; the spectroscopy and photophysics of neutral and monocationic PAHs; the photostabilities of PAH monocations and dications and their astrophysical implications.


1977 ◽  
Vol 1977 (1) ◽  
pp. 617-620 ◽  
Author(s):  
Shinichi Nagata ◽  
Goro Kondo

ABSTRACT Changes with elapsed time are presented for five kinds of oils that were studied through the analyses of GLC method, where particularly we made an attempt to examine the relationship among specific gravity, viscosity, and the amount of water in oils. Furthermore, we tried to evaluate a few processes of various kinds of changes on the physical and chemical properties of oils such as evaporation, biodegradation, and photo-decomposition. The evaporation process was found to affect mainly paraffins with smaller boiling points, below the number of C12-C13, for 21 days, while due to the action of marine bacteria, normal paraffins were effectively degraded (ca. 50%) after 15 days except for branched ones. Moreover, it was also found that the aromatic hydrocarbons with anthracene ring and heteroaromatic ones, which were not easily decomposed by the processes mentioned above, were fairly decomposed by photo-irradiation for 10 hours.


1987 ◽  
Vol 120 ◽  
pp. 545-546 ◽  
Author(s):  
Alain Omont

There is substantial evidence of the presence of polycyclic aromatic molecules, mainly hydrocarbons (PAH's) in the interstellar medium (Léger and Puget, 1984, Allamandola et al. 1985, Léger and d'Hendecourt in these proceedings). They should contain typically NC = 20–100 carbon atoms, and they can contain perhaps 1–10% of the total interstellar carbon. I have recently discussed in detail their physical and chemical properties (Omont, 1986), which should be intermediate between that of conventional interstellar molecules and grains.


1966 ◽  
Vol 24 ◽  
pp. 101-110
Author(s):  
W. Iwanowska

In connection with the spectrophotometric study of population-type characteristics of various kinds of stars, a statistical analysis of kinematical and distribution parameters of the same stars is performed at the Toruń Observatory. This has a twofold purpose: first, to provide a practical guide in selecting stars for observing programmes, second, to contribute to the understanding of relations existing between the physical and chemical properties of stars and their kinematics and distribution in the Galaxy.


2017 ◽  
pp. 31-43
Author(s):  
Berta Ratilla ◽  
Loreme Cagande ◽  
Othello Capuno

Organic farming is one of the management strategies that improve productivity of marginal uplands. The study aimed to: (1) evaluate effects of various organic-based fertilizers on the growth and yield of corn; (2) determine the appropriate combination for optimum yield; and (3) assess changes on the soil physical and chemical properties. Experiment was laid out in Randomized Complete Block Design, with 3 replications and 7 treatments, namely; T0=(0-0-0); T1=1t ha-1 Evans + 45-30-30kg N, P2O5, K2O ha-1; T2=t ha-1 Wellgrow + 45-30-30kg N, P2O5, K2O ha-1; T3=15t ha-1 chicken dung; T4=10t ha-1 chicken dung + 45-30-30kg N, P2O5, K2O ha-1; T5=15t ha-1 Vermicast; and T6=10t ha-1 Vermicast + 45-30-30kg N, P2O5, K2O ha-1. Application of organic-based fertilizers with or without inorganic fertilizers promoted growth of corn than the control. But due to high infestation of corn silk beetle(Monolepta bifasciata Horns), its grain yield was greatly affected. In the second cropping, except for Evans, any of these fertilizers applied alone or combined with 45-30-30kg N, P2O5, K2O ha-1 appeared appropriate in increasing corn earyield. Soil physical and chemical properties changed with addition of organic fertilizers. While bulk density decreased irrespective of treatments, pH, total N, available P and exchangeable K generally increased more with chicken dung application.


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