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Enthalpies of formation for three- and eight- membered heterocyclic ethers (15 compounds) in gas state have been determined by different theoretical methods: levels of theory B3LYP/6-31g(d), MP2/6-31g(d) and chemical composite methods (Gn and CBS) via two approach’s: atomization energy (AE) and bond separations (BS). Median absolute deviations (MAD) and standard deviations (SD) of calculated values from experimental data have been determined for every using method’s. The bond separation method has the smallest MAD at most of theoretical methods in comparison to the atomization energy approach. The 6-31g(d,p) basis set doesn’t seen clear effect in the theoretical results.
Enthalpy of formation for three- and seven- membered heterocyclic theoethers (11 compound) in gas state have been determined by different theoretical methods: compo-site methods (Gn, CBS) and two levels of theory B3LYP/6-31g(d) and MP2/6-31g(d) via two approaches: atomization energy (AE) and bond separation (BS). Median abs-lute deviations (MAD) and standard deviations (SD) of calculation values from experi-ment data have been determined for every used theoretical method. It has been observed that the bond separation approach produce lower value of MAD in most of the theoretical methods in comparison to the atomization energy approach; where the G3MP2 method produce lower value of MAD, while the deviations corresponding to the two levels of theory MP2/6-31g(d)//B3LYP/6-31g(d) and MP2/6-31g(d)//B3LYP /6-31g(d) is close to the deviations of the composite methods. The 6-31g(d,p) basic set doesn't show substantial effect in the theoretical results.
In this paper, we studied flow and boiling regimes of two-phase forced flow in vertical tubes to determine the dominated flow and boiling regime at any region of tube. Studied Ranges of main parameters were: Pressure. Because of absence an accurat e method of flow and boiling regimes prediction, some of experimental equations of two phase flow (liquid-steam) had been used to determine the dominated flow and boiling regime in vertical tubes and build algorithm written by Matlab environment describes these regimes. An analytical study was provided of the resulted diagrams and suggestions were given for next studies .
Kinetic studies were carried out on the reaction between ′4,4-Methylenebis (2-methylcyclohexylamine) and dimeric fatty acid C36 in molten state by using a catalyst of sulpheric acid compared with the same kinetic of reaction without catalyst. The reaction was performed at 150, and 160 ˚C and followed by determining the acid value of the product.The polyamidation reaction was found to be of overall a second order until equilibrium state. Moreover, the catalyst increases speed of the reaction. Polyamidation reaction was automatic whereas the value of free energy was negative and the reaction was endothermic, and this is shown in change of positive enthalpy values.
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