JOURNAL OF CHEMICAL THERMODYNAMICS
·
2023
·
IF 2.6
Juan Wang,Zenghui Li,Xianyang Meng,Jiangtao Wu
In this work, liquid densities of n -octane, ethylcyclohexane and their binary mixtures {( x ) n -octane) + (1 − x ) ethylcyclohexane} with mole fraction x = (0.200, 0.400, 0.600, 0.800) are reported. The density measurements were performed with a high-pressure vibrating-tube densimeter at temperatures from (283 to 363) K and pressures up to 60 MPa. The combined expanded uncertainties (0.95 level of confidence, k = 2) are estimated to be 16 mK for temperature, 0.062 MPa for pressure, and up to 0.6 kg/m 3 for density. The experimental densities were correlated using the modified Tait equation. The average absolute percentage deviations of measurement results from the modified Tait equation correlations of n -octane, ethylcyclohexane and their binary mixtures {( x ) n -octane) + (1 − x ) ethylcyclohexane} are all lower than 0.1%. The isothermal compressibility and isobaric expansivity have also been derived from the experimental densities.
研究领域:
化学工程
·
物理化学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF CHEMICAL AND ENGINEERING DATA
·
2017
·
IF 2.323
Ying Zhang,Yutian Chen,Yu Zheng,Xinxin He,Maogang He
The speed of sound in n-octane and isooctane (2,2,4-trimethylpentane) was measured by the Brillouin light scattering (BLS) method. The examined regions for n-octane are T = (297–580) K along five isobaric lines at p = 0.1, 4.0, 7.0, 10.0, and 12.0 MPa for liquid and T = (573–673) K along ten isobaric lines with p = (3.0–10.0) MPa for supercritical fluid. The examined regions for isooctane are T = (294–525) K along five isobaric lines at p = 0.1, 3.0, 6.0, 10.0, and 12.0 MPa for liquid and T = (543–630) K along six isobaric lines with p = (3.0–10.0) MPa for supercritical fluid. The relative expanded uncertainty of the speed of sound is estimated less than 1.3%. Polynomial representations for the speed of sound in liquid n-octane and isooctane were fitted to the experimental results, respectively. The AADs are 0.27% for n-octane and 0.19% for isooctane. The influence of temperature and pressure on the speed of sound was also analyzed. Moreover, the data were also used to assess the predicted ability of three equations of state for n-octane.
研究领域:
物理化学
·
热力学
✓ 已验证
产品关联
DOI
高影响因子
FLUID PHASE EQUILIBRIA
·
2021
·
IF 2.775
Xiong Zheng,Dan Qu,Fa Zhang,Yu Liu,Guangzhao Qin
Hydrocarbons play an important role in lots of industrial processes. Thermal conductivity is an important thermophysical property of fluids in energy conversion process, such as the design of the heat transfer system and the evaluation of thermodynamic cycle. Thus, it is of great significance to acquire solid experimental data and develop reliable models for achieving accurate thermal conductivity of hydrocarbons. In this work, thermal conductivity of two common fuels, n-octane and n-decane, were studied by combining experimental and theoretical methods. Using the transient hot wire method, the thermal conductivity is measured with temperature ranging from 303 to 523 K and pressures ranging from 0.1 to 15 MPa. Excellent agreement is achieved by comparing our experimental results with literatures. Furthermore, the mechanism for the influence of temperature and pressure on thermal conductivity of liquid n-octane and n-decane was explored preliminarily based on Bridgman's theory. In addition, we proposed a modified model considering the critical thermal conductivity enhancement, with which the average absolute deviations are 0.49% and 0.43% for n-octane and n-decane, respectively. It is shown that our proposed model has better predictive ability for representing thermal conductivity than the four traditional theoretical models (Assael model, Sun and Teja model, Huber and Perkins model, Liu model), especially at the vicinity of the critical point. The achievements in the present study are not only useful for relevant industrial application but also helpful for understanding the thermal conductivity critical enhancement when approaching the liquid-gas critical point for n-alkanes.
研究领域:
化学工程
·
热物理
✓ 已验证
产品关联
DOI
高影响因子
Journal of Spectroscopy
·
2020
·
IF 1.243
Liang Zhao,Chaoyu Jing,Yu Jin,Jiangping Chen,Ke Yin,Sujun Yang,Bingqing Liu,Xiao Han,Jianyu Tan
The optical constants of a liquid hydrocarbon such as liquid n-octane are basic material properties that may be used to evaluate their thermal radiation transfer capabilities. In this study, the ellipsometry method was used to measure the optical constants of liquid n-octane in the midinfrared wavelength range of 2.0–16.0 μm at temperatures of 20, 50, and 80°C. Experimental analyses indicate the significant effect of temperature on the refractive index, although it has little effect on the absorption index. With increasing temperature, the refractive index shows a linear decrease, and reduced density leads to weaker absorption intensities. The radiative properties of n-octane droplets, including the absorption and scattering efficiency factors of single droplets with droplet radii r = 10, 20, 50, and 100 μm and the absorption and scattering coefficients in a droplets-air system of droplet volume fractions fv = 2%, 3%, and 4%, were calculated using Mie theory. The numerical results indicate that, with increasing temperature, the absorption efficiency factor slightly decreases, and the variation trend of the scattering efficiency factor is more complicated. With increasing droplet radius, the absorption efficiency factor increases within the studied wavelength range, except for certain absorption peaks, but the scattering efficiency factor tends to decrease. While the absorption is greater, the scattering is weaker for a given droplet radius. With an increasing volume fraction of n-octane droplets, the absorption and scattering coefficients increase linearly within the studied wavelength range.
研究领域:
热物理学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF CATALYSIS
·
2013
·
IF 5.787
Lin Guo,Yu Fan,Xiaojun Bao,Gang Shi,Haiyan Liu
Silicoaluminophosphate (SAPO-11) samples with enhanced acidity were synthesized by two-stage crystallization in the presence of dodecyltrimethylammonium bromide (DoTAB), in which the Si source was added after the aluminophosphate framework was formed. The structure, elemental composition, acidity, Si environment, and n-octane di-branched isomerization of the as-synthesized SAPO-11 with small crystallites were investigated. The results showed that compared with the conventional one-stage crystallization, the two-stage crystallization produced more Si borders in the resulting SAPO-11. Among the SAPO-11 samples synthesized by two-stage crystallization, the SAPO-11 with the optimal DoTAB content (mol(DoTAB)/mol(SiO 2 ) = 0.015) had the most Si( n Al) (0 < n < 4) species with moderate and strong Brønsted acidity. The catalyst based on the small crystallite SAPO-11 containing a greater number of moderate and strong Brønsted acid sites exhibited superior performance for n-octane di-branched isomerization. This two-stage DoTAB-assisted crystallization opens a new route to enhancing the SAPO-11 acidity and can be extended to the other SAPO molecular sieves.
研究领域:
化学工程
·
催化科学
·
材料科学
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）