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Register a new userDetermination of The Enthalpy of Formation of Three- and Eight- Membered Heterocyclic Ethers in Ideal Gas by Diffe-rent Theoretical Methods via Atomization Energy and Bond Separation Schemes
تحديد انتالبيات تشكل المركبات الإيتيرية الحلقية الثلاثية حتى الثمانية غير المتجانسة في الحالة الغازية بالطرائق النظرية المختلفة من خلال طاقات التذري و مخططات فصل الروابط
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تم تحديد انتالبيات تشكل المركبات الإيتيرية الحلقية الثلاثية حتى الثمانية (15مركباً) في الحالة الغازية بالطرائق النظرية المختلفة: السويتين النظريتين B3LYP/6-31g(d) وMP2/6-31g(d)، و الطرائق الكيميائية المركبة Gn) و (CBS من خلال طاقات التذري (AE) و مخططات فصل الروابط (BS). حدد الانحراف الوسطي المطلق (MAD) و الانحراف القياسي (SD) للمعطيات النظرية عن القيم التجريبية لكل طريقة نظرية مستخدمة. تقدم طريقة فصل الروابط أصغر قيمة للانحراف الوسطي المطلق لمعظم الطرائق النظرية مقارنة بتقريب طاقة التذري. لا تبدي المجموعة الأساسية 6-31g(d,p) تأثيراً واضحاً في النتائج النظرية.
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.
References used
COBOS C.J. Heats of formation for AlH, AlOH, OAlH and OAlOH and their monocations. THEOCHEM, V. 581, 2002, P. 17–29
BERRY R.J.; EHLERS C.J.; BURGESS D.R. JR.; ZACHARIAH M.R., NYDEN M.R.; SCHWARTZ M. Halon thermochemistry: Ab initio calculations of the enthalpies of formation of fluoroethanes. THEOCHEM, V. 422, 1998, P. 89–98
SUDLOW K.P.; WOOLF; A.A., Heats of formation of carbonyl, formyl and trifluoroacetyl fluorides. J FLUORINE, 96(2), 1999, P.141–145
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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.
The Diels - Alder reactions of furan and some derivatives with maleic anhydride
have been studied using methods of density functional theory (DFT): B3LYP, B3PW91,
MPW1PW91 and MPW1BPE with 6-31g(d) bases set and proceeding energy cor-relation
at M
P4 level of theory with same bases set. The results of this study showed that, for the
Diels - Alder reaction of Furan and 2-methyl furan with maleic anhydride, the reaction of
formation of exo-adduct proceeds under thermodynamical control, and the reaction of
formation of endo-adduct proceeds under kinatic control, but for the 2-furylmethanol, 2-
furylmethyl acetate and 2-furylmethyl benzoate, the reactions of formation of exo-adduct
proceed under thermodynamical and kinetic controls. The MPW1BPE/6-31g(d) level of
theory was advanced susceptible results by comparison with the reference experimental
data; exactly for furan-maleic anhydride Diels - Alder reaction.
Gas condensate consists essentionaly of two kinds of compounds:
hydrocarbon compounds and nonhydrocarbon compounds such as
(CO2, H2S, N2, H2O……..). Nonhydrocarbon compounds form a
very small rate in gas condensate ,but it effect on many properties
of
gas condensate. This research studies the effect of these componentson the pseudocritical pressure and pseudocritical temperature of gas condensate which are very important to study the phase behavioure of gas condensate and to determine the region of retrograde phenomenas which happen in gas condensate reservoirs.The study was done by presenting some methods to calculate these properties and the correcting of these values if there are nonhydrocarbon components in the condensate . the calculations were made by Stewartt methode and we put a computed program to calculate the correcting pseudocritical properties and noncorrecting ones, then we compear the tow values by drawing many diagrams between the mole fraction of the component and the calculated pseudocritical temperature and pressure.
This paper includes was clarified the objectives of this study and
the problems caused by gas hydrate formation problem in the
studied gas transportation lines, and submit of the studied fields,
contains all the required data in this research.
The 1,3-dipolar cycloaddition of the aryl azide and some its of derivatives with cinnamic
acid was studied theoretically using different methods of Density Functional Theory
(DFT): B3LYP, B3PW91, MPW1PBE, MPW1PW91 and M062X with the basic set 6-
3
1g(d). Most of the used levels of theories provide closed results qualitatively, and the
results of the level of theory M062X / 6-31g (d) show that these reactions in the gas state
carried out spontaneously to form several stable energy products; the products P1 and P2
are most stable, but all the reactions are very slow and one of the products P1 is more
spontaneous than P2 , but the formation reaction of P2 is faster.
On the other hand, when these reactions were studied with different solvents, it is found
that solvents to have no actual effects on the rates of these reactions.
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