JOURNAL OF THERMAL ANALYSIS AND CALORIMETRY
·
2014
·Vol. 119
·期 1
·205-212
·
IF 2.206
Yang Ting,Chen Liping,Chen Wanghua,Zhou Yishan,Gao Haisu,Zhong Tingting
2-Ethylhexyl nitrate (EHN) is an important material, which is produced by concentrated HNO 3 –H 2 SO 4 nitration process. But EHN is not a stable material, especially mixed with acids. To analyze the stability of EHN with concentrated acid under serious condition, four samples (pure EHN, concentrated sulfuric acid with EHN, concentrated nitric acid with EHN, and mixed acid with EHN) and three acids (sulfuric acid, nitric acid, and mixed acid) were measured by differential scanning calorimeter (DSC) and accelerating rate calorimeter (ARC) in this paper. The results indicated that concentrated sulfuric acid, concentrated nitric acid, and mixed acid all could decrease the onset decomposition temperature of EHN, especially concentrated sulfuric acid. DSC results also showed that the heat of EHN decomposition with nitric acid is larger than other samples. Based on ARC data, the kinetic parameters and T
D24 (temperature at which TMR
ad is 24 h) were calculated. The activation energy and T
D24 of the EHN with acids, especially with concentrate sulfuric acid, were much lower than the pure EHN. It can be concluded that acids could decrease the stability of EHN and that is an important reason for frequent accidents.
研究领域:
物理化学
·
安全工程
·
材料化学
·
热分析
·
危险品管理
✓ 已验证
DOI
高影响因子
CELLULOSE
·
2021
·Vol. 28
·期 5
·3249-3264
·
IF 5.044
Sun Ling,Xie Yutong,Wu Jiamin,Wang Huixin,Wang Shihao,Li Wennan,Zhang Jiaojiao,Zhang Zheng,Zhu Ping,Lu Zhou,Dong Chaohong
A novel flame retardant containing phosphorus and nitrogen elements, ammonium salt of N,N-dimethylene p-benzenesulfonic phosphonic acid (ADBSPA), was prepared by one-step continuous chemical method. The chemical structure of the ADBSPA was determined by nuclear magnetic resonance spectrum (NMR) and Fourier transform infrared (FTIR), and ADBSPA was processed onto cotton materials by immersion method. The flame retardancy of coated cotton materials was analyzed by limiting oxygen index (LOI) and Vertical burning test. The LOI value of cotton coated with 350 g/L ADBSPA increased from the original 18.2 ± 0.2% to 31.7 ± 0.2%, and the damaged length of this sample reduced to 6.6 ± 0.1 cm, which proved that ADBSPA enhanced the anti-burning ability of cotton materials. Cone calorimetry was used to evaluate the combustion behavior of cotton materials before and after coating. Compared with original sample, ADBSPA changed the combustion path of cotton materials, and the intuitive performance was that the ADBSPA-cotton-4 reserved 25.1 ± 0.5% of char residue at 250 s, and its peak heat release rate (PHRR) greatly reduced to 17 ± 1 kW/m 2 . The surface morphology of uncoated and coated cotton materials was characterized by scanning electron microscopy (SEM). It was observed that the coated sample still maintained a complete fiber skeleton after burning. In addition, thermogravimetric (TG) analysis confirmed that the coated cotton materials had good thermo-oxidative and thermal stability. All results pointed out that the phosphorus and nitrogen elements contained in ADBSPA as well as cotton cellulose constituted the three basic conditions of intumescent flame-retardant system. The polyphosphoric acid compounds formed by phosphorus element at high temperature promoted the dehydration of cotton fibers into char layer. The non-flammable gases produced by the nitrogen element in the combustion process covered the surface of fabrics, thereby playing the role of shielding heat and diluting combustible gases. Graphic abstract A novel phosphorus-nitrogen flame retardant was prepared by one-step continuous chemical method and applied to improve the thermal stability and anti-flammability of cotton materials.
研究领域:
材料科学
·
纺织工程
·
化学工程
✓ 已验证
DOI
高影响因子
CELLULOSE
·
2025
·
IF 4.8
Fan Zuwei,Xue Yihai,Liu Hao,Yu Yuanyuan,Liu Rangtong
To improve the flame-retardant performance of cotton fabric, multiple crosslinked layers were constructed on cotton fiber surfaces through polymerization of m -phenylenediamine (MPD)/tetrakis hydroxymethyl phosphonium chloride (THPC) and trimesoyl chloride (TMC). The resulting morphology, general properties, flame retardancy, and durability were characterized and analyzed. Cotton fabric alternately finished with MPD-TMC and THPC-TMC displayed greater changes in surface morphology than that finished with single crosslinked products. The former material had the highest weight gain percentage and so possessed significantly higher limiting oxygen index (LOI) value and weaker heat release, accompanied by formation of a more robust carbonaceous layer during micro combustion calorimetry. After alternating finishing with MPD-TMC and THPC-TMC, the cotton fabric exhibited increased flexural rigidity and decreased air permeability, with the change influenced by the number of finishing cycles. Increased finishing cycles also resulted in an increased LOI, up to 33.5% after five cycles. According to micro combustion calorimetry results, heat release was suppressed more effectively as long as the number of finishing cycles reached three, such that finishing with 3 cycles was optimal in this study. Moreover, a fabric with 3 cycles of alternating finishing almost kept its LOI value after washing in disturbed water for 24 h, exhibiting good durability for flame retardancy, which would be beneficial in real applications. Graphical abstract
研究领域:
材料科学
·
纺织工程
✓ 已验证
产品关联
DOI
高影响因子
CHINESE JOURNAL OF CHEMICAL ENGINEERING
·
2016
·
IF 1.207
Changshuai Shen,Wenli Li,Cairong Zhou
The molar heat capacities ( C p ) of guaiacol (CAS 90-50-1) and acetyl guaiacol ester (AGE, CAS 613-70-7) were determinated from 290 K to 350 K by differential scanning calorimetry (DSC), and expressed as a function of temperature. Two kinds of group contribution models were used to estimate the molar heat capacities of both guaiacol and AGE, the average relative deviation is less than 10%. The standard molar enthalpies of combustion of guaiacol and AGE were − 3590.0 kJ·mol − 1 and − 4522.1 kJ·mol − 1 by a precise thermal isolation Oxygen Bomb Calorimeter. The standard molar enthalpies of formation of guaiacol and AGE in a liquid state at 298.15 K were calculated to be − 307.95 kJ·mol − 1 and − 448.72 kJ·mol − 1 , respectively, based on the standard molar enthalpies of combustion. The thermodynamic properties are useful for exploiting the new synthesis method, engineering design and industry production of AGE using guaiacol as a raw material.
研究领域:
物理化学
·
热力学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF THERMAL ANALYSIS AND CALORIMETRY
·
2019
·Vol. 141
·期 2
·783-796
·
IF 2.471
Ding Jiong,Yu Liming,Wang Xiaona,Xu Qiyue,Yang Suijun,Ye Shuliang,Jiang Juncheng
The accelerating rate calorimetry is a powerful tool for thermal hazard evaluation. However, the existing kinetics approaches ignore the fact that the thermal inertia is varying during the pseudo-adiabatic reaction because of the changing of the sample’s heat capacity and heat loss. To overcome this shortcoming, the expression of the thermal inertia is amended based on the heat balance and transfer in this article. The arithmetic product of the sample’s heat capacity and the amended thermal inertia is obtained by merging the kinetic results of the DSC and ARC data. Then, the data from the ARC are corrected and the more reasonable values of the kinetic parameters are computed based on the varying thermal inertia consideration. With the typical n -order and autocatalytic decomposition experiments under the different sample masses, the validity of the proposed kinetic approach is verified. Meanwhile, the hypotheses of the proposed approach are analyzed and discussed in the end of the article.
研究领域:
化学工程
·
安全科学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF CHEMICAL AND ENGINEERING DATA
·
2020
·
IF 2.369
Jinghao He,Dejun Dong,Fan Yang,Lihui Sun,Xing Yu,Zhanping Yang,Xuedong Zhu,Yinchun Liang
In the present study, the solid–liquid phase diagrams of four systems acetic acid + acetic anhydride, propionic acid + acetic anhydride, butyric acid + acetic anhydride, and pentanoic acid + acetic anhydride were determined by differential scanning calorimetry at atmospheric pressure. The experimental results illustrated that these systems showed a eutectic behavior. The experimental data were compared with predicted data acquired by solving the phase equilibrium equations using an algorithm. The liquid-phase activity coefficients were calculated by the Wilson and nonrandom two-liquid activity coefficient models. The results show that the approaches used for the calculated system equilibrium was capable to accurately describe the eutectic solid–liquid phase diagrams of the above-mentioned systems.
研究领域:
物理化学
·
热力学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF CHEMICAL AND ENGINEERING DATA
·
2022
·
IF 3.119
Shaohua Lv,Yun Hao,Bohao Yang,Linghong Tang
In this article, a calorimeter was established on the basis of steady-flow calorimetry. The present calorimeter was utilized to measure the isobaric heat capacity (cp) of target fluids. First, water was measured to verify the reliability of the experimental system. Then the measurements of cp for methyl hexanoate and ethyl hexanoate were carried out at temperatures from 313 K to 433 K and pressures of up to 10 MPa. To implement easier industrial application, a correlation was proposed on the basis of the experimental data to calculate the cp values of methyl hexanoate and ethyl hexanoate, with maximum absolute relative deviations of 0.77% and 0.65%, respectively. The newly reported data will be helpful for use with methyl hexanoate and ethyl hexanoate.
研究领域:
化学工程
·
热力学
✓ 已验证
产品关联
DOI
高影响因子
THERMOCHIMICA ACTA
·
2024
·
IF 3.1
Huimin Yan,Fan Yang,Nan Yin,Yan Kou,Quan Shi
Adiabatic calorimetry is a reliable method for determining the purity of organic compounds, offering significant advantages over chromatography by eliminating the need for impurity separation. Despite its longstanding application, research in this area has been limited. This study comprehensively assessed the purity of tetradecanoic acid, n-heptadecane, and phenol using adiabatic calorimetry, comparing the results with those obtained through chromatography. The results demonstrated that tetradecanoic acid purity can be accurately measured, while n-heptadecane exhibited satisfactory repeatability in purity determination without sample separation in polycrystalline forms. Furthermore, the purity of phenol was effectively assessed using adiabatic calorimetry, where chromatography faced challenges. Overall, this study validates adiabatic calorimetry as a robust technique for organic compound purity determination and suggests avenues for further research in this domain.
研究领域:
化学
·
分析化学
✓ 已验证
产品关联
DOI
高影响因子
Arabian Journal of Chemistry
·
2018
·
IF 2.969
Dashuang Fan,Zhiguo Hao,Peizhu Zheng,Jihua Zhao,Weiguo Shen
The influence of water-soluble polyethylene glycols PEG200 on the properties of sodium bis(2-ethylhexyl)-sulfosuccinate (AOT) water-in-isooctane microemulsions has been investigated by conductivity measurement and isothermal titration microcalorimetry (ITC). The percolation temperatures ( T p ), the thermodynamic properties of droplet aggregation and the interaction enthalpy (−Δ H φ ) between droplets for AOT/water/PEG200/isooctane with different PEG concentrations and a fixed molar ratio of water to surfactant ω = 22.2 were determined. Based on a two-stage thermodynamic approach of the percolation, we obtained the fusion enthalpy (Δ H f 0 ) of the close contact droplets by a combination of the droplet aggregation enthalpy (Δ H ag 0 ) and −Δ H φ . It was found that both (−Δ H φ ) and (Δ H f 0 ) varied with the concentration of PEG200 ( c PEG ) and had the extreme value at c PEG = 25 g L −1 . This phenomenon was interpreted by the variation of interface rigidity due to the varied distributions of added PEG200 between the water pool and the surfactant interface.
研究领域:
胶体化学
·
物理化学
✓ 已验证
产品关联
DOI
高影响因子
FLUID PHASE EQUILIBRIA
·
2013
·
IF 2.379
Chun-Mei Qi,Li-Sheng Wang,Jun-Chao Du,Guo-Min Yu,Gui-Qin Sun
1,2-Bis (2-oxo-5,5-dimethyl-1,3,2-dioxyphosphacyclohexyl-2-imino) ethane (BPEA) was prepared, and characterized by elemental analysis (EA), mass spectra (MS), infrared spectroscopy (IR) and nuclear magnetic resonance (NMR). The melting point and the enthalpy of fusion of BPEA were performed on differential scanning calorimetry (DSC), and the thermal stability of BPEA was tested by thermogravimetric analysis (TGA). The solubility of BPEA in selected solvents was measured by a static analytical method. The experimental data were correlated with different thermodynamic models, such as the empirical equation and non-random two liquid (NRTL), Wilson, Scatchard–Hildebrand, and universal quasi chemical (UNIQUAC) equations. The calculated results showed good agreement with the experimental data in the temperature range studied.
研究领域:
化学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
CHINESE CHEMICAL LETTERS
·
2011
·Vol. 22
·期 12
·1497-1500
·
IF 0.775
Xiao Zheng Lan,Hai Rong Pei,Chuan Xian Cheng
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.
研究领域:
物理化学
·
材料科学
·
纳米科技
·
热力学
✓ 已验证
DOI
高影响因子
THERMOCHIMICA ACTA
·
2025
·
IF 3.5
Yuxin Yang,Chunhua Lou,Huixiao Wang,Jingjing Yu
In this study, dicyandiamide (DCD) was modified with o-aminoacetophenone to synthesize a new curing agent for epoxy resin (EP), called o-acetylphenylguanidine (o-APG). The experimental results showed that the yield of o-APG could reach 85.79% under the optimal ratio. The structure of o-APG was characterized via Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, X-ray diffraction analysis, and nuclear magnetic resonance spectroscopy. The result deduced that the compatibility of o-APG with EP was significantly improved because reacted to form the group. The curing kinetics of the reaction of EP cured with o-APG was investigated via differential scanning calorimetry (DSC) by using the methods of Kissinger, Ozawa, Starink, and Friedman. The DSC analysis result showed that curing temperature was reduced by about 50 °C compared with the DCD-cured EP.
研究领域:
材料科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）