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- Author or Editor: W. Liu x
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Abstract
The extraction of cobalt by Winsor II microemulsion system was studied. In the bis (2-ethylhexyl) sulfosuccinate sodium salt (AOT)/n-pentanol/n-heptane/NaCl system, AOT was used as a anionic surfactant to form microemulsion in n-heptane, n-pentanol was injected in the microemulsion as a cosurfactant. Co(II) was found to be extracted into the microemulsion phase due to ion pair formation such as Co2+(R–SO3 −)Cl. The influence of different parameters such as the volume ratio of aqueous phase to microemulsion, surfactant concentration, pH of the feed solutions, cosurfactant concentration as well as temperature on the extraction yield (E%) were investigated. The results showed that it was possible to extract 95% of cobalt by the AOT Winsor II microemulsion.
Abstract
Dodecylamine hydrochloride C12H25NH3·Cl(s) and bis-dodecylammonium tetrachlorozincate (C12H25NH3)2ZnCl4(s) were synthesized by the method of liquid phase reaction. The constant-volume energy of combustion of dodecylamine hydrochloride was measured by means of a RBC-II precision rotating-bomb combustion calorimeter at T = (298.15 ± 0.001) K. The standard molar enthalpy of formation of C12H25NH3·Cl(s) was calculated to be 
(C12H25NH3·Cl, s) = −(706.79 ± 3.97) kJ mol−1 from the constant-volume energy of combustion. In accordance with Hess’ law, a reasonable thermochemical cycle was designed and the enthalpy change of the synthesis reaction of the complex (C12H25NH3)2ZnCl4(s) was determined by use of an isoperibol solution-reaction calorimeter. The standard molar enthalpy of formation of (C12H25NH3)2ZnCl4(s) was calculated as 
[(C12H25NH3)2ZnCl4, s] = −(1862.14 ± 7.95) kJ mol−1 from the standard molar enthalpy of formation of C12H25NH3·Cl(s) and other auxiliary thermodynamic data.
Abstract
Zinc formate dihydrate has been synthesized and characterized by powder X-ray diffraction, elemental analysis, FTIR spectra and thermal analysis. The molar heat capacity of the coordination compound was measured by a temperature modulated differential scanning calorimetry (TMDSC) over the temperature range from 200 to 330 K for the first time. The thermodynamic parameters such as entropy and enthalpy vs. 298.15 K based on the above molar heat capacity were calculated. The thermal decomposition characteristics of this compound were investigated by thermogravimetric analysis (TG) and differential scanning calorimetry (DSC). TG curve showed that the thermal decomposition occurred in two stages. The first step was the dehydration process of the coordination compound, and the second step corresponded to the decomposition of the anhydrous zinc formate. The apparent activation energy of the dehydration step of the compound was calculated by the Kissinger method using experimental data of TG analysis. There are three sharply endothermic peaks in the temperature range from 300 to 650 K in DSC curve.
Abstract
Phase behavior of dodecane–tetradecane (n-C12H26–C14H30, n-C12–C14) binary system in bulk and confined in SBA-15 (pore diameters 8 nm; 15.9 nm) has been investigated by differential scanning calorimetry and transmission electron microscopy. The bulk system possesses some special phases relating to the rotator phase in normal alkanes. Dodecane–tetradecane mixtures confined in SBA-15 (8 nm) are a system miscible both in solid and liquid states with a phase diagram of a smooth curve. Dodecane–tetradecane system confined in SBA-15 (15.9 nm) exhibits not only solid–liquid (s–l) in all compositions but solid–solid transition in mole fractions of tetradecane 0.1–0.6, which forms a phase diagram of “loop line” shape. Melting temperatures of n-C12–C14/SBA-15 (8 nm) are lower than those of n-C12–C14/SBA-15 (15.9 nm) in all mole fractions. The evolution of the phase diagram of n-C12–C14 confined in 8 nm, 15.9 nm pore sizes of SBA-15 and in bulk, respectively, shows a dramatic effect of confinement on phase behavior of normal alkane mixtures. The s–l phase boundary lines of n-C12–C14/SBA-15 (8, 15.9 nm) are fitted as 
being [
], where D is a polynomial ∑ a
i
x
i
, i = 1, 2,···, n (A = C14, B = C12).
Abstract
Bis(1-octylammonium) tetrachlorocuprate (1-C8H17NH3)2CuCl4(s) was synthesized by the method of liquid phase reaction. The crystal structure of the compound has been determined by X-ray crystallography. The lattice potential energy was obtained from the crystallographic data. Molar enthalpies of dissolution of (1-C8H17NH3)2CuCl4(s) at various molalities were measured at 298.15 K in the double-distilled water by means of an isoperibol solution-reaction calorimeter, respectively. In terms of Pitzer's electrolyte solution theory, the molar enthalpy of dissolution of (1-C8H17NH3)2CuCl4(s) at infinite dilution was determined to be 
and the sums of Pitzer's parameters 
and 
were obtained.
Abstract
Effects of retorting factors on combustion properties of shale char
Part 4. Combustion characteristics
Abstract
For obtaining high shale oil yield as well as treating shale char efficiently and in an environmentally friendly way in a new comprehensive utilization system of oil shale, a series of fundamental experiments have been conducted for exploring the effects of retorting factors on shale oil yield and shale char characteristics. Based on these previous studies, in this article, combustion experiments of shale chars obtained under various retorting conditions were performed with a Q5000IR thermogravimetric analyzer and a Leitz II-A heatable stage microscope and the effects of retorting factors were discussed on the combustion characteristics of shale char. Among four studied retorting parameters, retorting temperature and residence time exert very significant influence on the combustion characteristics of shale char. Either elevating the retorting temperature from 430 to 520 °C or lengthening the residence time at a low retorting temperature will largely decrease residual organic matters within shale char, resulting in decreasing mass loss in the low-temperature stage of combustion process of shale char, an elevation of ignition temperature and a shift of ignition mechanism from homogeneous to heterogeneous. One set of retorting condition was also recommended as a reference for designing the comprehensive utilization system of oil shale studied in this work: retort temperature of 460–490 °C, residence time of 20–40 min, particle size of <3 mm, and low heating rate of <10 °C/min.
Abstract
Thermogravimetry (TG) was employed to study the thermal degradation kinetics of poly(etherketone/sulfone)ethylimide (PEK-IE and PES-IE). The corresponding decomposition activation energies and reaction orders were obtained and the comparison was made with their parent polymerspoly(ether-ketone/sulfone) with Cardo group (PEK-C and PES-C). The results show that the degradation activation energies of PEK-IE and PES-IE were lower than that of PEK-C and PES-C; and two stages of the degradation process were found for all the four polymers. For PEK-IE and PES-IE, the activation energies in the first decomposition stage are much lower than that in the second stage and the two stages can be taken as slow induction and fast degradation, whereas for PEK-C and PES-C the activation energies in the first decomposition stage are larger than that in the second stage, and the two stages can both be taken as two fast degradation stages. The decomposition mechanism of the two stages was also speculated.
Summary Samples of electrolytic manganese dioxide (EMD) were chemically reduced using 2-propanol under reflux (82°C) for 1, 2, 3, 6 and 24 h intervals. XRD analysis showed that the ?-MnO2 structure was preserved although the lattice dimensions were observed to increase with increasing degree of reduction to accommodate the intercalation of protons. The exception was the 24 h reduced sample which contained two phases; ? -MnO2 and ? -MnOOH. Three regions of decomposition in the range of 50 to 1000°C were observed using thermogravimetric analysis coupled with mass spectrometry (TG-MS) and were accounted for as water removal below 390°C, reduction of MnO2 to Mn2O3 between 400 and 600°C, and Mn2O3 to Mn3O4 between 600 and 1000°C. Again the exception proved to be the 24 h reduced sample which was observed to decompose predominantly in one step between 400 and 600°C directly to Mn3O4.
Abstract
Pb(1,4-BDC)·(DMF)(H2O) (1,4-BDC=1,4-benzenedicarboxylate; DMF=dimethylformamide) has been synthesized and investigated by elemental analysis, FTIR spectroscopy, thermogravimetry (TG), derivative thermogravimetry (DTG). TG-DTG curves show that the thermal decomposition occurs in four stages and the corresponding apparent activation energies were calculated with the Ozawa-Flynn-Wall (OFW) and the Friedman methods. The most probable kinetic model function of the dehydration reaction of the compound has been estimated by the Coats-Redfern integral and the Achar-Bridly-Sharp differential methods in this study.
