کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
672972 1459480 2015 7 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Thermodynamic properties and low-temperature X-ray diffraction of vitamin B3
موضوعات مرتبط
مهندسی و علوم پایه مهندسی شیمی جریان سیال و فرایندهای انتقال
پیش نمایش صفحه اول مقاله
Thermodynamic properties and low-temperature X-ray diffraction of vitamin B3
چکیده انگلیسی


• Тemperature dependence of heat capacity of vitamin B3 has been measured by precision adiabatic vacuum calorimetry.
• The thermodynamic functions of the vitamin B3 have been determined for the range from T → 0 to 346 K.
• The thermodynamic analysis of reactions involving nicotinic acid was made.
• The low-temperature X-ray diffraction was used for the determination of coefficients of thermal expansion.

In the present work temperature dependence of heat capacity of vitamin B3 (nicotinic acid) has been measured for the first time in the range from 5 to 346 K by precision adiabatic vacuum calorimetry. Based on the experimental data, the thermodynamic functions of the vitamin B3, namely, the heat capacity, enthalpy H°(T) – H°(0), entropy S°(T) – S°(0) and Gibbs function G°(T) – H°(0) have been determined for the range from T → 0 to 343 K. The value of the fractal dimension D in the function of multifractal generalization of Debye’s theory of the heat capacity of solids was estimated and the character of heterodynamics of structure was detected. The thermodynamic parameters ΔfS°, ΔfG° at T = 298.15 K and p = 0.1 MPa have been calculated. The thermodynamic analysis of reactions involving nicotinic acid was made. The low-temperature X-ray diffraction was used for the determination of coefficients of thermal expansion.

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ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Thermochimica Acta - Volume 604, 20 March 2015, Pages 115–121
نویسندگان
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