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Herein, the phase behaviors of both bulk and confined deep eutectic solvents in controlled pore glasses were first investigated. Glass transition, cold crystallization and melting behaviors alter significantly in the nanopores due to the size effect and interfacial interactions. Kinetic analysis of the crystallization reveals increased effective activation energies and pre-exponential factors under nanoconfinement.

For the first time, we report the calorimetric effect and thermokinetics in the formation process of a model deep eutectic solvent (DES), ChCl:urea. Mixing of a 1-to-2 molar ratio of choline chloride and urea shows a rapid endothermic process under stirring. The rate constants and reaction orders are determined by analyzing the thermokinetic curves at several constant temperatures. Low activation energy and activation parameters demonstrate that the formation of this DES is a rapid process. Other thermodynamic parameters are also estimated.

The effect of nano-confinement on the phase transitions of heneicosane (n-C21H44, C21) were investigated using differential scanning calorimetry (DSC) and variable temperature powder X-ray diffraction (XRD). When C21 is confined within the pores of controlled pore glasses (CPGs), SBA-15 or other mesoporous materials, the solid-solid (Ts) and solid-liquid (Tm) transition temperatures are depressed. The depression of the phase transition temperatures (ΔTs, ΔTm) for C21 in CPGs and SBA-15, the degree of supercooling and enthalpy change (ΔHs, ΔHm) for C21 in CPGs, exhibited a linear dependence on the inverse pore size. The ΔTm values were insensitive to the polarity pore wall but varied with the pore geometry. XRD analysis revealed that the lamellar ordering characteristic for the solid C21 was disturbed in the nanopores, with the extent increasing as the pore size decreased. A new rotator phase RII is found for C21 confined in CPG (12 nm) and SBA-15 (14.4 nm).

To extend the use of phase change materials (PCMs) of those with good performance, tris(hydroxymethyl)aminomethane (THAM) is embedded in silica gels (SG) (pore diameter, d = 15–100 nm) and in controlled porous glasses (CPG) (nominal d = 12–100 nm). The THAM/SG and THAM/CPG composites are characterized by SEM and XRD. Latent heat storage performance of THAM/SG and THAM/CPG is investigated using differential scanning calorimetry, showing size dependence of phase transition temperature, enthalpy change and supercooling. THAM in the nanopores displays stable transition temperature and heat storage capacity in a short-term thermal cycling. The bulk and the nanosized THAM own the same diffraction patterns. The encapsulation of phase change material in nanoporous media is a promising way of tuning the thermal energy properties of those ideal PCMs for use in a wider range of temperature.

Latent heat storage performance of a layered perovskite-type compound, 1-C14H29NH3)2ZnCl4 (C14Zn), embedded in a series of silica gel (SG) with pore sizes of d = 15–200 nm is investigated using differential scanning calorimetry (DSC), and powder X-ray diffractions (XRD). C14Zn in the nanopores of silica gel shows size-dependent phase transition temperature, enthalpy change and supercooling. They have a stable transition temperature and heat capacity at each size in a short-term thermal cycling. Similar X-ray diffraction patterns are observed for the nano-sized and the bulk C14Zn. The encapsulation of a phase change material in nanopores is a new way of tuning its thermal energy storage properties for a wider range of temperature regulation.

Inspired by the interest in the confinement effect on polymorphism of alkane mixtures, phase behaviors of a hexadecane–heptadecane (n-C16H34–C17H36, C16–C17) binary system in the bulk and in nanopores of controlled porous glasses (CPGs) are investigated using differential scanning calorimetry (DSC) and temperature-dependent powder X-ray diffraction (XRD). As reported, bulk C16–C17 mixtures form two intermediate phases with monoclinic (Mdci) and orthorhombic (Op) structures in a low temperature range and rotator phase RI in high temperature range. In the pores of CPG (300 nm), these solid phases appear in the temperatures slightly below the bulk system. The RI one-phase region extends a bit in temperature range in the mixtures of high C17 components. In CPG (8.1 nm), the solid phases come up in much lower temperatures than the bulk. The rotator RI is found in a larger range of the temperature and composition than the bulk and in CPG (300 nm). A new phase, the rotator RII, is observed in a narrow temperature range of high C17 composition just before melting. XRD analysis shows diffractions from the alkane layered ordering in CPG (300 nm) with a more roughened layer surface than the bulk. Lamellar stacking of the solids in CPG (8.1 nm) is heavily perturbed. The variation in the polymorphism of C16–C17 mixtures in the nanopores is associated with the reduced ordering of the molecule arrangements. These results can help to understand the influence of confinement effect on binary mixtures of alkanes, the chain molecules.

The nanoconfinement effect on the phase behaviors of octacosane (n-C28H58, C28) was studied using differential scanning calorimetry (DSC) and X-ray diffraction (XRD). In the nanopores of controlled pore glasses (CPGs), silica gels (SGs), SBA-15, and KIT-6, C28 showed depressed phase transition temperatures. The depression of phase transition temperatures, degree of supercooling and enthalpies of phase transitions for C28 confined in the CPGs, SGs and SBA-15 exhibited a linear dependence on reverse pore diameter. The phase transition temperatures also varied with the changing pore geometry, and the depression of melting points of C28 in SBA-15 is about 2 times larger than that in the CPGs and SGs. The interfacial interactions of the pore walls to alkane seem to have a negligible influence on the phase behaviors. The phase transition sequences of the pore-confined C28 changed largely with the appearance of new RI and RII rotator phases.

As an important and interesting question, the delicate influence of confinement effect on properties of fluids in nanopores still needs deeper understanding. To this regard, phase behaviors of normal hexadecane (n-C16H34, C16) absorbed in porous materials are investigated. Phase transitions of C16 in SBA-15 (7.8 and 17.2 nm), CPG (8.1 and 300 nm), C-SBA-15 (15.6 nm) (carbon coated), and KIT-6 (8.6 nm) were scanned using differential scanning calorimetry (DSC) and temperature-dependent powder X-ray diffraction (XRD) in cooling and heating processes. The bulk C16 is known to form a transient rotator phase RI on cooling. In this work, freezing and melting points of C16 in the nanopores are found to be depressed. C16 in the large pores of CPG (300 nm) only shows a triclinic phase. In the pores of diameters d = 7.8–17.2 nm, C16 exhibits stable or metastable rotator phase RI or RII. The stabilization of the rotators by nanoconfinement is more obvious in smaller pores or with stronger pore surface interactions d...

Solid–liquid phase behaviors of the hexadecane–octadecane (n-C16H34–C18H38, C16–C18) system in the bulk, and confined in controlled porous glass (CPG) are investigated using differential scanning calorimetry and temperature-dependent powder X-ray diffraction. Bulk C16–C18 mixtures show the special rotator phase RI, and two intermediate phases with monoclinic (Mdcp) and orthorhombic (Op) structures. Inside CPG (8.1 and 300 nm), the RI and Op phases could be found in wider compositions of the solid mixtures than the bulk, however the Mdcp form was not observed. Unexpectedly, under the confinement of CPG (8.1 nm) not only the rotator RI appeared in the two pure components, C16 and C18, but a rotator phase RII occurred in the pure C18 and most of the mixtures upon heating. These new phase behaviors of the confined alkanes could be attributed to the size effect and the interface interactions. According to XRD analysis, in the small pores of CPG (8.1 nm) the alkane molecules effectively take the 2D arrangements...

Phase behaviors of dodecane–hexadecane (n-C12H26–C16H34, C12–C16) binary mixtures in bulk and confined in SBA-15 (pore diameters 3.8, 9.5, and 17.2 nm) are investigated using differential scanning calorimetry. According to the thermal analysis, the bulk mixtures belong to a system of partial miscibility with two solid solutions and a eutectoid in the range of mole fraction \( x_{{{\text{C}}_{ 1 6} }} \) = 0.1–0.8. Under confinement, phase behavior of C12–C16 mixtures is distinct from the bulk. Inside pores of SBA-15 (3.8 nm), the solid mixtures has only a melting boundary. In the pores larger than 9.5 nm, phase behaviors of the mixtures show some resemblance to the bulk system. The growth of the phase diagram with the pore diameter clearly shows the size effect on the phase behavior of the confined mixtures. In comparison with those of chain length difference of pure components of two carbon atoms or less, C12–C16 mixtures exhibit different phase behaviors not only in the bulk but also in the confined state.

Phase behavior of dodecane–tridecane (n-C12H26–C13H28, C12–C13) mixtures in bulk and confined in SBA-15 have been investigated using differential scanning calorimetry. Bulk C12–C13 system has a complicated behavior due to special rotator phase. It has been found that phase diagram of C12–C13/SBA-15 (3.8 nm) system is a straight line, C12–C13/SBA-15 (7.8 nm) a curve, and C12–C13/SBA-15 (8.9, and 17.2 nm) a loop line. The growth of the phase diagram shows size effect on phase behavior of C12–C13 mixtures. Moreover, in the range of 3.8–17.2 nm melting temperatures of pure C12 and mixtures at mole fractions xC13 = 0.1–0.5 have linear relation with inverse pore diameter, while C13 and mixtures at xC13 = 0.6–0.9 present curved lines. The confined mixtures show a similar melting behavior with pure C12, C13.

Phase behavior of normal decane–dodecane (n-C10H22–C12H26, C10–C12) system confined in SBA-15 (Santa Barbara Amorphous, pore diameters 3.8, 7.8, and 17.2 nm) has been studied by using differential scanning calorimetry. It has been found solid–liquid phase diagram of the C10–C12/SBA-15 system is composed of a straight line (3.8 nm), a curve (7.8 nm) and a loop line (17.2 nm). The growth of the phase diagram clearly shows the size effect on phase behavior of binary alkanes. Phase behavior has been compared among the systems C10H22–C12H26/SBA-15, C12H26–C14H30/SBA-15 and C14H30–C16H34/SBA-15.

Phase behavior of binary system of bromobenzene–chlorobenzene (C 6 H 5 Br–C 6 H 5 Cl) confined in SBA-15 and MCM-41 (pore diameter 8 nm, 3.8 nm, respectively) has been investigated by means of differential scanning calorimetry (DSC). Phase diagram of C 6 H 5 Br–C 6 H 5 Cl system confined in SBA-15 is a type of the complete miscible both in liquid and solid state, the same phase behavior as the bulk system. However, the phase diagram comprises only one boundary line, which is shifted down 22–36 K with respect to the bulk system. C 6 H 5 Br, C 6 H 5 Cl or the mixture within nanopores of MCM-41 is nonfreezing. The different phase behavior of the system confined in SBA-15 and MCM-41 is thought mainly due to the relative size of pore to molecule.

Rare earth elements have been widely used in many areas. Rare earth complex bearing an amino acid was synthesized to study the influence and the long-term effect of rare earth elements on environment and human beings, because amino acid is the basic unit of the living things. Previous work on these kinds of complex is focused on synthesis and characterization of them. But their thermodynamic data have seldom been reported. Here we present the thermodynamic study of [ Ho (Thr) (H2O)(5)] Cl-3. The heat capacity of Holmium complex with threonine, [ Ho (Thr) ((HO)-O-2)(5)] Cl-3, was measured with an automatic adiabatic calorimeter in the temperature range from 79 K to 330 K and no thermal anomaly was found in this range. Thermodynamic functions relative to standard state 298.15 K were derived from the heat capacity data. Thermal decomposition behavior of the complex in nitrogen atmosphere in the range from 300 K to 900 K was studied by thermogravimetric (TG) technique and a possible decomposition mechanism was proposed according to the TG-DTG results.

For heat energy storage application, polyurea. microcapsules containing phase change material, n-eicosane, were synthesized by using interfacial polymerization method with toluene- 2,4-diisocyanate (tdi) and diethylenetriamine (deta) as monomers in an emulsion system. poly(ethylene glycol)octyl-phenyl ether (op), a nonionic surfactant, was the emulsifier for the system. the experimental result indicates that tdi was reacted with deta in a mass ratio of 3 to 1. ft-ir spectra confirm the formation of wall material, polyurea, from the two monomers, tdi and deta. encapsulation efficiency of n-eicosane is about 75%. microcapsule of n-eicosane melts at a temperature close to that of n-eicosane, while its stored heat energy varies with core material n-eicosane when wall material fixed. thermo-gravimetric analysis shows that core material n-eicosane, micro-n-eicosane and wall material polyurea can withstand temperatures up to 130, 170 and 250 degreesc, respectively.

A novel gelling method was studied to stabilize phase change material Na2HPO4 · 12H2O with amylose grafted sodium acrylate. Gelled Na2HPO4 · 12H2O shows stable heat storage performance prepared at optimized conditions: 2.7mass/mass% sodium acrylate, 0.4 mass/mass% amylose, 0.05–0.09 mass/mass% N, N′-methylenebisacrylamide, 0.05–0.09 mass/mass% K2S2O8 and Na2SO3 (mass ratio 1:1), at 50 °C. Na2HPO4 · 12H2O was dispersed in gel network as tiny crystals less than 0.1 mm. Melting points were in the range 35.4 ± 2 °C. Short-term thermal cycling proves the effectiveness of the novel method for eliminating phase separation in the gelled salt. Adiabatic calorimetric measurement of heat capacities shows two phase transitions, which correspond to melting of Na2HPO4 · 12H2O and freezable bond water in gel, respectively. Heat of fusion of pure Na2HPO4 · 12H2O was determined as 260.9 J g−1. Distribution of extra water is: free water:freezable water:nonfreezing water = 0:0.85:0.15.

Radical-substituted radical cations are attractive spin building blocks of molecule-based magnets. The introduction of an additional spin as a counteranion provides a unique three-spin system wherein the magnetic interactions between the spins of the radical substituent and the radical cation (J(intra)) and those between the spins of the radical cation and the anion (J(inter)) play decisive roles in determining the magnetic properties of the system. We report the first demonstration of a ferrimagnet by utilizing a large-J(intra) system, nitronyl nitroxide-substituted dihydrophenazine radical cation (NNDPP(*+)) in combination with tetrabromoferrate (FeBr(4)(-)) as the counteranion. On the basis of measurements of dc and ac magnetic susceptibilities and heat capacity, the magnetic properties of NNDPP(*+) x FeBr(4)(-) are elucidated to be those of a three-dimensional long-range-ordered ferrimagnet with T(c) = 6.7 K.

In this paper, a novel SPME mode, PDMS-coated solid glass microspheres (SGMs), were prepared by sol–gel method. Using homemade thermal desorption unit coupled with CGC-FID, six PAHs as model analytes, the performance of the new mode was characterized. The new extractive phase exhibited high thermal stability and satisfactory extraction capability. The detection limits were 0.01–0.045 ng/mL, and the linearity was from 0.5 ng/mL to 96 ng/mL. The R.S.D.s of repeatability for retention time and peak area were all within 0.074% and 6.7%, respectively. The recoveries of the PAHs were 78–127% from the samples taken from river water.

Disodium hydrogen phosphate dodecahydrate (Na2HPO4 center dot 12H(2)O) is an attractive candidate for phase change materials. The main problem for its practical use comes from incongruent melting character during thermal cycling. Experimentally, heat of fusion of the pure salt decreased from 200 to 25 J center dot g (-1) in a four-run freeze-thaw cycling. Additives such as thickening agent or in-situ synthesized polyacrylate sodium in the molten salt can prevent its phase separation to some extent. In the test, sodium alginate 3.0% - 5.0% (w/w) thickened mixture containing Na2HPO4 center dot 12H(2)O and some water showed constant heat storage capacities. Polyacrylate sodium gelled salt was synthesized through polymerizing sodium acrylate in the melt of Na2HPO4 center dot 12H(2)O and some extra water at 50 degrees C. Optimum conditions composed of sodium acrylate 3.0%-5.0% (w/w), cross-linking agent N,N-methylenebis-acrylamide 0.10%-0.20% (w/w), K2S2O8 and Na2SO3 (mass ratio 1 : 1) 0.06%-0.12% (w/w). As opposed to normal large, crystals of pure Na2HPO4 center dot 12H(2)O in solid state, the gelled salt existed in a large number of tiny particles dispersed in the gel network at room temperature, commonly less than 2 mm. But only those sample particles with sizes less than 0.2 mm may have relatively stable thermal storage property. A problem encountered was the poor reproducibility of the synthesis method: heat storage capacity of the product was often very different even though the synthesis was carried out in the same conditions. An alternative gelling method by sodium alginate Grafted sodium acrylate was tried and it showed a fairly good effect. Heat capacities and heat of fusion of Na2HPO4 center dot 12H(2)O were measured by an adiabatic calorimeter.

The molar heat capacities of the two biphenyl liquid crystals, 3BmFF and 3BmFFXF3, with a purity of 99.7 mol% have been precisely measured by a fully automated precision adiabatic calorimeter in the temperature range between T = 80 and 350 K. Nematic phase-liquid phase transitions were found between T = 297 K and 300 K with a peak temperature of T-peak = (298.071 +/- 0.089) K for 3BmFF, and between T = 316 and 319 K with a peak temperature of T-peak = (315.543 +/- 0.043) K for 3BmFFXF3. The molar enthalpy (Delta(trs)H(m)) and entropy (Delta(trs)S(m)) corresponding to these phase transitions have been determined by means of the analysis of the heat capacity curves, which are (15.261 +/- 0.023) U mol(-1) and (51.202 +/- 0.076) J K-1 mol(-1) for 3BmFF, (31.624 +/- 0.066) kJ mol(-1) and (100.249 +/- 0.212) J K-1 mol(-1) for 3BmFFXF3, respectively. The real melting points (TI) and the ideal melting points (TO) with no impurities of the two compounds have been obtained from the fractional melting method to be (298.056 +/- 0.018) K and (298.165 +/- 0.038) K for 3BmFF, (315.585 +/- 0.043) K and (315.661 +/- 0.044) K for 3BmFFXF3, respectively. In addition, the transitions of these two biphenyl liquid crystals from nematic phase to liquid phase have further been investigated by differential scanning calorimeter (DSC) technique; the repeatability and reliability for these phase transitions were verified. (C) 2004 Elsevier B.V. All rights reserved.

The heat capacities of rare earth complex with amino acid histidine, [Er 2 (His·H + )(H 2 O) 8 ](ClO 4 ) 6 ·4H 2 O, were measured with an automatic adiabatic calorimeter from 79 to 320 K. It was found that there was a sudden increment in heat capacity within the temperature range 182–190 K. Thermal decomposition behavior of the complex in nitrogen atmosphere was studied by thermogravimetric (TG) analysis, and a possible decomposition mechanism was suggested according to TG–DTG results.

The constant volume energy of combustion of crystalline 3,5-di- tert -butylsalicylic acid ( t -BSA) in oxygen at 298.15 K was determined using combustion calorimeter to be −8292.57±2.51 kJ mol −1 . The standard molar enthalpies of combustion and formation of 3,5-di- tert -butylsalicylic acid were derived, at T =298.15 K, Δ c H m Θ =−8302.48±2.51 kJ mol −1 and Δ f H m Θ =−744.30±3.21 kJ mol −1 , respectively. The heat capacities of the compound were measured with an adiabatic calorimeter over the temperature range from 79 to 351 K. No indication of any phase transition or thermal anomaly was observed in this temperature range. The fusion and evaporation behavior of the compound were examined by thermogravimetry (TG), differential thermal analysis (DTA) and differential scanning calorimetry (DSC). The molar enthalpy and entropy of fusion, Δ fus H m Θ and Δ fus S m Θ , at T =437.5 K, were determined to be 22.92±0.55 kJ mol −1 and 139.4±3.3 J mol −1 K −1 , respectively; and the molar enthalpy and entropy of evaporation, Δ vap H m Θ and Δ vap S m Θ , at T =477.5 K, were obtained as 83.88±2.1 kJ mol −1 and 341.7±8.4 J mol −1 K −1 , respectively.

The molar heat capacities (c-p,c-m) of crystalline potassium dichromate (k2cr2o7 (cr)) and aqueous k2cr2o7 solution (0.1699 mol(.)kg(-1)) were measured in the temperature range from 100 to 390 k and from 80 to 370 k by an automatic adiabatic calorimeter equipped with a small cell of internal volume of 6 cm(3), respectively. no phase transition took place in the temperature range from 100 to 390 k for k2cr2o7 (cr). the relationships of c-p,c-m of k2cr2o7 (cr) with respect to t were established to be c-p,c-m = 177.53 + 161.92x - 138.14x(2) - 209.67x(3) + 160.35x(4) + 137.44x(5) - 41.291x(6) and c-p,c-m = 177.52 + 171.66x - 149.59x(2) - 246.17x(3) + 194.79x(4) + 167.30x(5) - 64.368x(6) (x = (t - 245.00)/145.00) for series i and series 2 experiments, respectively. no phase transition took place for the solution from 80 to 270 k. the function of c-p,c-m of the solution with respect to t was established to be c-p,c-m = 0.137t + 2.5068 [j(.)k(-1.)mol(-1)]. a fusion transition at t-fus = 272.19 k was found from the c-p,c-m-t curve of the solution. the molar enthalpy and entropy of the phase transition were calculated to be 6.115 kj(.)mol(-1) and 22.47 j(.)k(-1.)mol(-1), respectively. the molar heat capacities of the solution are about a constant in the temperature range from 275 k to 370 k, c-p,c-m =76.75 +/- 1.12 [j(.)k(-1.)mol(-1)]. the thermodynamic data of k2cr2o7 (cr) and the solution were derived from the heat capacity data and the relationship of thermodynamic functions. (c) 2003 editions scientifiques et medicales elsevier sas. all rights reserved.

The heat capacities of two kinds of rare-earth element solid complexes with isoleucine [Re 2 (Ile) 4 (H 2 O) 8 ](ClO 4 ) 6 (whereRe = Nd, Er, and Ile = isoleucine) have been measured by an automatic adiabatic calorimeter in the temperature rangefrom 80 to 370K. Two solid–solid phase transitions were found from the C p curve of Nd formed complex in the rangeof 165–175K with a peak temperature of 167.88K and in the range of 195–210K with a peak temperature of 202.13K.The corresponding molar enthalpies of these phase transitions were determined to be 404.61Jmol −1 and 2.955kJmol ,respectively. One solid–solid phase transition was found for the Er formed complex in the range of 190–205K with a peaktemperature of 193.42K. The corresponding molar enthalpy of this transition was 14.11kJmol −1 . Smooth heat capacities andthermodynamic functions relative to the standard state (298.15K), H T − H 298 . 15 , S T − S 298 . 15 and −[ G T − G 298 . 15 ], of thetwo compounds, were calculated on basis of experimental heat capacity data. Possible mechanisms of thermal decompositionsfor the pair of compounds were suggested according to the thermogravimetric (TG) analysis.© 2002 Elsevier Science B.V. All rights reserved.

Two solid-state coordination compounds of rare earth metals with glycin, [Gd 4/3 Y 2/3 (Gly) 6 (H 2 O) 4 ](ClO 4 ) 6 ·5H 2 O and [ErY(Gly) 6 (H 2 O) 4 ](ClO 4 ) 6 ·5H 2 O were synthesized. The low-temperature heat capacities of the two coordination compounds were measured with an adiabatic calorimeter over the temperature range from 78 to 376 K. [Gd 4/3 Y 2/3 (Gly) 6 (H 2 O) 4 ](ClO 4 ) 6 ·5H 2 O melted at 342.90 K, while [ErY(Gly) 6 (H 2 O) 4 ](ClO 4 ) 6 ·5H 2 O melted at 328.79 K. The molar enthalpy and entropy of fusion for the two coordination compounds were determined to be 18.48 kJ mol −1 and 53.9 J K −1 mol −1 for [Gd 4/3 Y 2/3 (Gly) 6 (H 2 O) 4 ](ClO 4 ) 6 ·5H 2 O, 1.82 kJ mol −1 and 5.5 J K −1 mol −1 for [ErY(Gly) 6 (H 2 O) 4 ](ClO 4 ) 6 ·5H 2 O, respectively. Thermal decompositions of the two coordination compounds were studied through the thermogravimetry (TG). Possible mechanisms of the decompositions are discussed.

Heat capacities of two solid complexes of rare-earth elements with glycine [RE(Gly)3(H2O)2]Cl3·2H2O (RE=Pr, Nd, Gly=Glycine) have been measured with a high-precision automatic adiabatic calorimeter over the temperature range from 78 to 380 K. The melting point, molar enthalpy and entropy of fusion for the two complexes were determined on the basis of the heat capacity measurements. Thermal decompositions of the two complexes were studied by thermogravimetric (TG) techniques and a possible mechanism for the decompositions is suggested.

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.

A solid complex of rare-earth compounds with alanine, [ErY(Ala)4(H2O)8](ClO4)6 (Ala=alanine), was synthesized, and a calorimetric study and thermal analysis for it was performed through adiabatic calorimetry and thermogravimetry. The low-temperature heat capacity of [ErY(Ala)4(H2O)8](ClO4)6 was measured with an automated adiabatic precision calorimeter over the temperature range from 78 to 377 K. A solid-solid phase transition was found between 99 and 121 K with a peak temperature at 115.78 k. The enthalpy and entropy of the phase transition was determined to be 1.957 Kj mol-1, 16.90 j mol-1 k-1, respectively. Thermal decomposition of the complex was investigated in the temperature range of 40~550°C by use of the thermogravimetric and differential thermogravimetric (TG/DTG) analysis techniques. The TG/DTG curves showed that the decomposition started from 120 and ended at 430°C, completed in three steps. A possible mechanism of the thermal decomposition was elucidated.

To stabilize phase change material, disodium hydrogen phosphate dodecahydrates (na2hpo4 center dot 12h2o), a novel gelling method by polymerizing sodium alginate grafted sodium acrylate in its molten salt was investigated. the optimum synthesis conditions to obtain product with stable heat storage performance were 2.8% (w/w) sodium acrylate, 0.3-0.4% (w/w) sodium alginate, 0.1-0.19% (w/w) nap-methylenebisacrylamide and 0.06% (w/w) k2s2o8 and na2so3, at 50 degrees c. na2hpo4 center dot 12h(2)o was dispersed in the as-synthesized gel network as tiny crystals less than 0.1 mm. melting points were in the range 35.4 +/- 2 degrees c. short-term thermal cycling proves the effectiveness of the novel gelling method for eliminating phase separation in the gelled salt. (c) 2007 published by elsevier b.v.

The synthesis and the solid state magnetic properties of (nitronyl nitroxide)-substituted trioxytriphenylamine radical cation tetrachlorogallate, NNTOT(+)⋅GaCl(4)(-), are reported. In the temperature region between 300 and 3 K, the magnetic behavior is characterized by the strong intramolecular ferromagnetic interaction (J/k(B)=+400 K) between the radical (NN) and the radical cation (TOT(+)) and the weak intermolecular antiferromagnetic interaction (J/k(B)=-1.9 K) between NNTOT(+) ions. Below 3 K, a 3D-type long-range magnetic ordering into a weak ferromagnet was observed (T(N)=2.65 K). The magnetic entropy (S(mag)=8.97 J K(-1) mol(-1)) obtained by the heat capacity measurement is in good agreement with the theoretical value of R ln3=9.13 J K(-1) mol(-1) based on the S=1 state.