Thermochemical properties and thermokinetic behavior of energetic triazole ionic salts

The properties of dissolution in different solvents,the specific heat capacity and thermal decomposition process under the non-isothermal conditions for energetic triazole ionic salts 1,2,4-triazolium nitrate(1a),1,2,3-triazolium nitrate(1b),3,4,5triamino-1,2,4-triazolium nitrate(2a),3,4,5-triamino-1,2,4-triazolium dinitramide(2b)were precisely measured using a Calvet Microcalorimeter.The thermochemical equation,differential enthalpies of dissolution(△difH m ),standard molar enthalpies of dissolution(△difH m ),apparent activation energy(E),pre-exponential constant(A),kinetic equation,linear relationship of specific heat capacity with temperature over the temperature range from 283 to 353 K,standard molar heat capacity(C p,m)and enthalpy,entropy and Gibbs free energy at 283–353 K,taking 298.15 K as the benchmark for 1a,1b,2a and 2b were obtained with treating experimental data and theoretical calculation method.The kinetic and thermodynamic parameters of thermal decomposition reaction,critical temperature of thermal explosion(Tb),self-accelerating decomposition temperature(TSADT)and adiabatic time-to-explosion(t)of 1a,1b,2a and 2b were calculated.Their heat-resistance abilities were evaluated.Information was obtained on the relation between molecular structures and properties of 1a,1b,2a and 2b.

Regularity of Thermochemical Properties of Ternary Complexes RE[（pdtc）3（phen）]

Treatment of hydrate rare-earth （RE=La, Pr, Nd, Sm-Lu） chloride with ammonium pyrrolidinyldithiocarboxylate （apdtc） and 1,10-phenanthroline （phen） gave rise to thirteen complexes with an empirical formula RE[（pdtc）3（phen）]. The enthalpies of solution of hydrate rare-earth （RE= Sm-Ho, Tm-Lu） chloride, apdtc and phen in ethanol were measured by an RD-496 Ш microcalorimeter at 298.15 K, along with the mixing enthalpy of ethanol solution of APDC and that of phen and the enthalpies of reaction of formation of the title complexes in ethanol. The enthalpies of reaction of formation of the title complexes in solid were available through a rationally thermochemical cycle. Using an RD-496 Ш microcalorimeter, a model was developed for calculating the specific heat capacity and the responding specific heat capacity of the complexes were determined. The thermochemical properties, including the enthalpies of solution of hydrate rare earth chloride in ethanol, the enthalpies of reaction of formation of the title complexes in ethanol, the enthalpies of reaction of formation of the title complexes in solid, the special heat capacities at room temperature, the standard molar enthalpies of combustion and the standard molar enthalpies of formation for this series of complexes versus the atomic numbers of rare earth, presented triplet effect, which is representative of certain covalent bond between RE and the ligands and the result of 4f electron not shielded fully by 5sSp.

Heat Capacity and Bond Dissociation Energy Calculations of Some Fluorinated Ethanol’s and its Radicals: CH_3-xCH₂F_xOH, CH₃CH_2-xF_xOH

Structures and thermochemical properties of these species were determined by the gaussian M-062x/6-31 + g (d, p) calculation enthalpies of formation for 19 fluorinated ethanol and some radicals were calculated with a popular Ab initio and density functional theory methods: The gaussian M-062x/6-31 + g (d, p) via several series of isodesmic reactions. Entropies (S298°K in Cal·Mol-1 K-1) were estimated using the M-062x/6-31 + g (d, p) computed frequencies and geometries. Contributions of entropy, S298°K, and heat capacities, Cp(T) due to vibration, translation, and external rotation of the molecules were calculated based on the vibration frequencies and structures obtained from the M-062x/6-31 + g (d, p) Density Functional Method. Potential barriers are calculated using M-062x/6-31 + g (d, p) density functional method and are used to calculate rotor contributions to entropy and heat capacity using integration over energy levels of rotational potential. Rotational barriers were determined and hindered internal rotational contributions for S298° - 1500°K, and Cp (T) were calculated using the rigid rotor harmonic oscillator approximation, with direct integration over energy levels of the intramolecular rotation potential energy curves. Thermochemical properties of fluorinated alcohols are needed for understanding their stability and reactions in the environment and in thermal process

Properties and applications of biochars derived from different biomass feedstock sources

In China,substantial agricultural and garden wastes are burned yearly.This practice not only wastes resources but also pollutes air.Corn straw and poplar leaves are typical agricultural and garden waste in China.In this study,corn straw and poplar leaves were used to prepare biochars with different pyrolysis temperatures(250℃,350℃,450℃,550℃and 650℃)and were labeled as CC(corn straw)and LC(poplar leaves),respectively.The biochars were characterized through elemental analysis,Brunauer-Emmett-Teller surface area analysis,scanning electron microscopy and Fourier transform infrared spectroscopy.Yield,ash content and biochar pH were also measured.Results showed that the two biochars possessed some similar characteristics with increasing pyrolysis temperature.These attributes included increased carbon content,biochar hydrophobicity,alkaline pH;decreased hydrogen and oxygen contents and polar functional group content;and enlarged surface area.The biochars also displayed some different characteristics,such as the obviously larger surface area of CC than that of LC at high pyrolysis temperatures and the regular holes of CC and irregular and disordered holes of LC.When biochars CC-650 and LC-650 were used as soil conditioners,the soil pH increased by 0.3 and 0.4 units,respectively,and the soil cation exchange capacity increased by 12.7%and 21.5%,respectively,with respect to those of the blank controls.