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Abstract  

The heat capacities of berberine sulphate [(C20H18NO4)2SO43H2O] were measured from 80 to 390 K by means of an automated adiabatic calorimeter. Smoothed heat capacities, H T-H 298.15 and S T-S 298.15 were calculated. The loss of crystalline water started at about 339.30.2 K, and its peak temperature was 365.80.6 K. The peak temperature of decomposition for berberine sulphate was at about 391.40.4 K by DSC curve. TG-DTG analysis of this material was carried out in temperature range from 310 to 970 K. TG and DSC curves show that there is no melting in the whole heating process.

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Abstract  

The heat capacities of trans-(R)-3-(2,2-dichloroethenyl)-2,2-dimethylcyclopropanecarboxylic acid in the temperature range from 78 to 389 K were measured with a precise automatic adiabatic calorimeter. The sample was prepared with the purity of 0.9874 mole fraction. A solid-liquid fusion phase transition was observed in the experimental temperature range. The melting point, T m, enthalpy and entropy of fusion, Δfus H m, Δfus S m, were determined to be 344.75±0.02 K, 13.75±0.07 kJ mol−1, 39.88±0.21 J K−1 mol−1, respectively. The thermodynamic functions of the sample, H (T)-H (298.15), S (T)-S (298.15) and G (T)-G (298.15), were reported with a temperature interval of 5 K. The thermal decomposition of the sample was studied by TG analysis, the thermal decomposition starts at ca. 421 K and terminates at ca. 535 K, the maximum decomposition rate was obtained at 525 K. The order of reaction, pre-exponential factor and activation energy, are n=0.14, A=1.15·108 min−1, E=66.27 kJ mol−1, respectively.

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Thermodynamic investigation of room temperature ionic liquid

Heat capacity and thermodynamic functions of BPBF4

Journal of Thermal Analysis and Calorimetry
Authors: Z. Zhang, L. Sun, Z. Tan, F. Xu, X. Lv, J. Zeng, and Y. Sawada

Abstract  

The molar heat capacities of the room temperature ionic liquid 1-butylpyridinium tetrafluoroborate (BPBF4) were measured by an adiabatic calorimeter in temperature range from 80 to 390 K. The dependence of the molar heat capacity on temperature is given as a function of the reduced temperature X by polynomial equations, C p,m [J K−1 mol−1]=181.43+51.297X −4.7816X 2−1.9734X 3+8.1048X 4+11.108X 5 [X=(T−135)/55] for the solid phase (80–190 K), C p,m [J K−1 mol−1]= 349.96+25.106X+9.1320X 2+19.368X 3+2.23X 4−8.8201X 5 [X=(T−225)/27] for the glass state (198–252 K), and C p,m[J K−1 mol−1]= 402.40+21.982X−3.0304X 2+3.6514X 3+3.4585X 4 [X=(T−338)/52] for the liquid phase (286–390 K), respectively. According to the polynomial equations and thermodynamic relationship, the values of thermodynamic function of the BPBF4 relative to 298.15 K were calculated in temperature range from 80 to 390 K with an interval of 5 K. The glass transition of BPBF4 was observed at 194.09 K, the enthalpy and entropy of the glass transition were determined to be ΔH g=2.157 kJ mol−1 and ΔS g=11.12 J K−1 mol−1, respectively. The result showed that the melting point of the BPBF4 is 279.79 K, the enthalpy and entropy of phase transition were calculated to be ΔH m = 8.453 kJ mol−1 and ΔS m=30.21 J K−1 mol−1. Using oxygen-bomb combustion calorimeter, the molar enthalpy of combustion of BPBF4 was determined to be Δc H m 0 = −5451±3 kJ mol−1. The standard molar enthalpy of formation of BPBF4 was evaluated to be Δf H m 0 = −1356.3±0.8 kJ mol−1 at T=298.150±0.001 K.

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Journal of Thermal Analysis and Calorimetry
Authors: X.-C. Lv, Z.-C. Tan, Z.-A. Li, Y.-S. Li, J. Xing, Q. Shi, and L.-X. Sun

Abstract  

The (R)-BINOL-menthyl dicarbonates, one of the most important compounds in catalytic asymmetric synthesis, was synthesized by a convenient method. The molar heat capacities C p,m of the compound were measured over the temperature range from 80 to 378 K with a small sample automated adiabatic calorimeter. Thermodynamic functions [H TH 298.15] and [S TS 298.15] were derived in the above temperature range with a temperature interval of 5 K. The thermal stability of the substance was investigated by differential scanning calorimeter (DSC) and a thermogravimetric (TG) technique.

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Abstract

To develop thermal stable flavor, two glycosidic bound flavor precursors, geranyl-tetraacetyl-β-D-glucopyranoside (GLY-A) and geranyl-β-D-glucopyranoside (GLY-B) were synthesized by the modified Koenigs–Knorr reaction. The thermal decomposition process and pyrolysis products of the two glycosides were extensively investigated by thermogravimetry (TG), differential scanning calorimeter (DSC) and on-line pyrolysis-gas chromatography mass spectroscopy (Py-GC-MS). TG showed the T p of GLY-A and GLY-B were 254.6 and 275.7°C. The T peak of GLY-A and GLY-B measured by DSC were 254.8 and 262.1°C respectively.

Py-GC-MS was used for the simply qualitative analysis of the pyrolysis products at 300 and 400°C. The results indicated that: 1) A large amount of geraniol and few by-products were produced at 300°C, the by-products were significantly increased at 400°C; 2) The characteristic pyrolysis product was geraniol; 3) The primary decomposition reaction was the cleavage of O-glycosidic bound of the two glycosides flavor precursors. The study on the thermal behavior and pyrolysis products of the two glycosides showed that this kind of flavor precursors could be used for providing the foodstuff with specific flavor during heating process.

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This study was to examine the effects of four fungal polysaccharides, namely exo-polysaccharide (EPS), water-extracted mycelia polysaccharide (WPS), sodium hydroxideextracted mycelia polysaccharide (SPS), and hydrochloric-extracted mycelia polysaccharide (APS) obtained from the endophytic fungus Bionectra pityrodes Fat6, on the sprout growth and flavonoids production of Fagopyrum tataricum. Without obvious changes in the appearance of the sprouts, the exogenous polysaccharide elicitors notably stimulated the sprout growth and functional metabolites accumulation, and the stimulation effect was mainly depended on the polysaccharide species along with its treatment dose. With application of 150 mg/l of EPS, 150 mg/l of WPS and 200 mg/l of SPS, the total rutin and quercetin yield of buckwheat sprouts was effectively increased to 49.18 mg/(100 sprouts), 50.54 mg/(100 sprouts), and 52.27 mg/(100 sprouts), respectively. That was about 1.57- to 1.66-fold in comparison with the control culture of 31.40 mg/(100 sprouts). Moreover, the present study revealed the accumulation of bioactive flavonoids resulted from the stimulation of the phenylpropanoid pathway by fungal polysaccharide treatments. It could be an efficient strategy for improving the nutritional and functional quality of tartary buckwheat sprouts applied with specific fungal elicitors.

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Abstract

In this paper, organic phase change materials (PCM)/Ag nanoparticles composite materials were prepared and characterized for the first time. The effect of Ag nanoparticles on the thermal conductivity of PCM was investigated. 1-tetradecanol (TD) was selected as a PCM. A series of nano-Ag-TD composite materials in aqueous solution were in-situ synthesized and characterized by means of thermal conductivity evaluation method, TG-DSC, IR, XRD and TEM. The results showed that the thermal conductivity of the composite material was enhanced as the loading of Ag nanoparticles increased. The composite materials still had relatively large phase change enthalpy. Their phase change enthalpy could be correlated linearly with the loading of TD, but their phase change temperature was a little bite lower than that of pure TD. The thermal stability of the composite materials was close to that of pure TD. It appeared that there was no strong interaction between the Ag nanoparticles and the TD. Furthermore, the experiment results indicated that the Ag nanoparticles dispersed uniformly in the materials, occurred in the forms of pure metal.

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Abstract  

The molar heat capacity, C p,m, of a complex of holmium chloride coordinated with L-aspartic acid, Ho(Asp)Cl2·6H2O, was measured from 80 to 397 K with an automated adiabatic calorimeter. The thermodynamic functions H T-H 298.15 and S T-S 298.15 were derived from 80 to 395 K with temperature interval of 5 K. The thermal stability of the complex was investigated by differential scanning calorimeter (DSC) and thermogravimetric (TG) technique, and the mechanism of thermal decomposing of the complex was determined based on the structure and the thermal analysis experiment.

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Abstract  

As one 3-D coordination polymer, lead formate was synthesized; calorimetric study and thermal analysis for this compound were performed. The low-temperature heat capacity of lead formate was measured by a precise automated adiabatic calorimeter over the temperature range from 80 to 380 K. No thermal anomaly or phase transition was observed in this temperature range. A four-step sequential thermal decomposition mechanism for the lead formate was found through the DSC and TG-DTG techniques at the temperature range from 500 to 635 K.

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Abstract  

Isoproturon [N'-(p-cumenyl)-N,N-dimethylurea] was synthesized, and the low-temperature heat capacities were measured with a small sample precise automatic adiabatic calorimeter over the temperature range from 78 to 342 K. No thermal anomaly or phase transition was observed in this temperature range. The melting and thermal decomposition behavior of isoproturon was investigated by thermogravimetric analysis (TG) and differential scanning calorimetry (DSC). The melting point and decomposition temperature of isoproturon were determined to be 152.4 and 239.0C. The molar melting enthalpy, and entropy of isoproturon, ΔH m and ΔS m, were determined to be 21.33 and 50.13 J K-1 mol-1, respectively. The fundamental thermodynamic functions of isoproturon relative to standard reference temperature, 298.15 K, were derived from the heat capacity data.

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