Print ISSN: 1812-125X

Online ISSN: 2664-2530

Main Subjects : Physical chemistry


Ab-initio and Statistical Calculations to predict the Rate Constant of Several Ethers Reactions with Chloramine-T

Ahmed M. Sadoon; Ayman Mohamed Taib

Journal of Education and Science, 2021, Volume 30, Issue 5, Pages 178-186
DOI: 10.33899/edusj.2021.126884.1196

Abstract.
The prediction of rate constant of Ethers reaction with Chloramine-T has been studied theoretically in this work using ab-initio and statistical calculations. The first order reaction between Ethers and Chloramine-T shows that the rate constant depends on the Ethers concentration. Therefore, ab initio calculations were used using DFT/ b3lyp with 6-311++G** as a basis set to extract the most stable geometry of the chosen ethers. Also, several physical parameters have been gained form these calculations such as mulliken charge at the active atoms, dipole moment, Homo and Lomo energy levels, Hardness, Electronic Chemical Potential and Global Electrophilicity Index. The relationship between these physical variables plays an effective role in the reaction rate. Therefore, statistical calculations were used to investigate the possible relationship between these physical parameters. These relationships can be predicted from the value of the correlation coefficient (R2) and the Standard error (SE). Simple regression analysis and multiple regression analysis were performed between these physical variables as independent variables and rate constant as a dependent variable using SPSS software. The results show high value of R2 (0.993) of the regression analysis which reflects the high relationship between these variables that affects the reaction rate concentration. The out data illustrates negligible differences (about 0.008) between the experimental and calculated rate constant value.

Calculation Values of potential Stickiness (S*) and Apparent Activation Energy (AAE) from Adsorption of Some Aromatic Carboxylic Acids on the Surface of a New Adsorbent Substance

Khaleel Ibrahim Alniemi

Journal of Education and Science, 2020, Volume 29, Issue 4, Pages 76-89
DOI: 10.33899/edusj.2020.126168.1021

Abstract:
This study includes calculation of the potential stickiness (S*) and apparent activation energy (AAE) by the adsorption process of some aromatic carboxylic acids using sand (clay) as a new adsorbent material. This clay was collected from dust storms coming to the city of Mosul. The obtained results showed that physical adsorption which is achieved by applying the modified Arrhenius equation through the values of (S *) and (AAE) which have low values and bear a negative charge is preferable Adsorption process occurs in two-step mechanism. The effect of the concentration of the acidic solution, temperature and the substituted groups SO3, NO2, OH, NH2 on the aromatic ring) was studied to clarify the nature of the association between organic carboxylic acid anions and inorganic metal oxides to form a complex surface model. The study concluded that the values of (S *) for all acids were less than one and they were more than the value of zero. Also, the values of (AAE) gave an indication that the adsorption process is exothermic and spontaneous. The presence of water molecules and (H+) ions in solution is very important to change the nature of the clay surface.

Preparation of Some Benzothiazole Polymers and Study Their Electrical Conductivity Properties

Asaad Faisal Khattab; Haitham Ahmed Ayoob; Laith Mohammed Altaan

Journal of Education and Science, 2020, Volume 29, Issue 4, Pages 140-153
DOI: 10.33899/edusj.2020.126945.1066

As the conjugated polymers are doped with some electron donor or acceptor dopants, their electrical conductivity increased thoroughly to about 10-6 Ω-1.cm-1. The doping of the polymers may give an n or p semiconductor characteristic according to the types of the dopants that are used. Within the frame of this work, four types of conjugated polymers with benzothiazole as a major moiety in their backbone have been prepared. The prepared monomers and polymers have been characterized by FTIR spectroscopy. Elemental analysis of the polymers (CHN) demonstrates their chemical structure while the DSC thermal analysis illustrates its Tg. The polymers were doped with two types of dopants, iodine and sodium iodide. The electrical conductivity of the doped polymers was measured with three probe cell. The results show increasing in the electrical conductivity with dopant concentration to some levels. The activation energy of the electrical conductivity process was also studied by measuring the electrical conductivity in different temperature. According to the magnitude of the activation energy, we can conclude that the chain flexibility is the dominate factor that influenced on electrical conductivity. Hall Effect and hot probe measurements reveal that the polymer can be considered as n or p type according to the type of the doping. It was concluded that the doping with iodine produced an n-type while the doping with sodium iodide produced the p- type.

Thermodynamic and Kinetic Study of Adsorption of Azo Dyes Derived for 4-amino Anti pyrene by Activated Carbon

Salah Hekmat

Journal of Education and Science, 2020, Volume 29, Issue 2, Pages 63-81
DOI: 10.33899/edusj.2019.125920.1006

A commercial activated carbon was used for the study of adsorption of two di- azo dyes from aqueous solution employing batch method. These dyes were synthesized in our laboratory from the reaction of 4-amino-antipyrene 4-AAP and β-Naphthol with p-amino phenol and p-amino benzaldehyde via diazonium ions. The effect of pH, temperature, and contact time on dye removal was investigated. The apparent thermodynamic parameters were estimated and the obtained results concluded that, the dyes adsorbed onto activated carbon are driven by entropy effect, exothermic and spontaneous processes. The kinetic study of adsorption of the considered dyes was conducted by applying four models the pseudo-first order, pseudo-second order ,Elovich and intra particules diffusion kinetic models. The results showed that, the second order equation fit better the experimental data. The intra particule diffusion model indicates that, there are more than mechanism
controlling the adsorption process.the adsorption process occurs through more than one mechanical and that the intra particule diffusion model is not the only mechanical that controls the adsorption of systems Studied.