Chemical Thermodynamics and Thermal Analysis最新文献_第10页

Thermodynamic studies for molecular interactions of tetraalkylammonium bromide salts in aqueous solutions: A volumetric approach 水溶液中四烷基溴化铵盐分子相互作用的热力学研究：体积法

Chemical Thermodynamics and Thermal Analysis

Pub Date : 2025-03-22 DOI: 10.1016/j.ctta.2025.100187

Vasim R. Shaikh , Sana R. Shaikh , Gaurav R. Gupta , Vijay M. Tangde , Kapil S. Ganorkar

Densities for aqueous solutions of tetraalkylammonium bromide (R₄NBr) salts, namely, tetramethylammonium bromide (Me₄NBr), tetraethylammonium bromide (Et₄NBr), tetra-n-propylammonium bromide (n-Pr₄NBr) and tetra-n-butylammonium bromide (n-Bu₄NBr) have been measured at 293.15, 298.15 and 303.15 K. Further, the experimental density data were used for the calculations of apparent molar volumes of solute at finite concentration (

V_{ϕ}

) and apparent molar volumes of solute at infinite dilution (

V_{ϕ}^{0}

) at studied temperatures. The

V_{ϕ}^{0}

values increase as the chain length increases and follow the order Me₄N⁺ < Et₄N⁺ < n-Pr₄N⁺ < n-Bu₄N⁺. The deviation parameter (B_V) found to be negative for studied salts in water, indicates that the tetraalkylammonium ions acts as water-structure making ions. The coefficient of thermal expansion (α) of solutions, apparent molar expansibility of solute at finite concentration (

E_{ϕ}

) and apparent molar expansibility of solute at infinite dilution (

E_{ϕ}^{0}

) were also calculated at 298.15 K. The

E_{ϕ}^{0}

values are found to be positive for the studied R₄NBr salts in water at 298.15 K and increases as the chain length increases. The result and analysis lead to the elaboration of hydrophobic interaction effects and concept like cation-cation (pair wise) and cation-anion-cation (triplet) interaction.

测定了四烷基溴化铵（R4NBr）盐的水溶液密度，即四甲基溴化铵（Me4NBr）、四乙基溴化铵（Et4NBr）、四正丙基溴化铵（n-Pr4NBr）和四正丁基溴化铵（n-Bu4NBr）在293.15、298.15和303.15 K时的密度。此外，实验密度数据用于计算在研究温度下有限浓度下溶质的表观摩尔体积（vφ）和无限稀释下溶质的表观摩尔体积（Vϕ）。Vϕ0值随着链长度的增加而增加，并遵循顺序为Me4N+ <；Et4N + & lt;n-Pr4N + & lt;n-Bu4N +。研究盐在水中的偏差参数（BV）为负，说明四烷基铵离子起着造水离子的作用。在298.15 K下，计算了溶液的热膨胀系数（α）、有限浓度下溶质的表观摩尔膨胀系数（Eϕ）和无限稀释时溶质的表观摩尔膨胀系数（Eϕ）。在298.15 K时，所研究的R4NBr盐在水中的Eϕ0值呈阳性，且随着链长的增加而增加。结果和分析导致了疏水相互作用效应和概念的阐述，如阳离子-阳离子（成对）和阳离子-阴离子-阳离子（三重态）相互作用。

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引用次数: 0

Dynamic viscosity and refractive index of aliphatic n-heptane with substituted aromatic hydrocarbons at T = (303.15 to 323.15) K and atmospheric pressure T = (303.15 ~ 323.15) K和大气压下脂肪族正庚烷与取代芳烃的动态粘度和折射率

Chemical Thermodynamics and Thermal Analysis

Pub Date : 2025-03-22 DOI: 10.1016/j.ctta.2025.100188

M. Abdur Rahaman , M. Kamrul Hossain , Shamim Akhtar , Hossain M. Shahadat

Dynamic viscosity and refractive index of aliphatic n-heptane with substituted aromatic hydrocarbons, such as toluene, o-xylene, and mesitylene were measured at T = (303.15 to 323.15) K and atmospheric pressure. The measurements were carried out over the whole range of composition using A-type Ostwald viscometer and Abbe Utility (Abbe 60/E) refractometer. From dynamic viscosity data, viscosity deviation and excess Gibbs free energy of activation were calculated, while the excess molar refraction was obtained from refractive index data. The values of dynamic viscosity and refractive index were fitted with concentration dependent 4th order polynomial equation and their excess values to the Redlich–Kister type polynomial equation. The viscosity deviation and excess free energy of activation with respect to mole fraction of aromatic hydrocarbons formed negative lobe with minima at x₂ = 0.55, whereas deviation of refractive index formed negative lobe for n-heptane + toluene system and positive lobe for n-heptane + o-xylene and n-heptane + mesitylene systems. Dispersive force is dominated in n-heptane + toluene system, whereas favorable geometric fitting is responsible for other two systems.

在T = (303.15 ~ 323.15) K和常压条件下，测定了脂肪族正庚烷与甲苯、邻二甲苯、三甲苯等取代芳烃的动态粘度和折射率。使用a型Ostwald粘度计和Abbe Utility （Abbe 60/E）折光计对整个组成范围进行了测量。根据动态黏度数据计算了黏度偏差和活化的过量吉布斯自由能，并根据折射率数据计算了过量摩尔折射率。用浓度相关的四阶多项式方程拟合了动态粘度和折射率的值，并将其超值拟合为Redlich-Kister型多项式方程。芳烃摩尔分数的黏度偏差和多余自由活化能在x2 = 0.55处呈最小负瓣，而折射率偏差在正庚烷+甲苯体系中呈负瓣，在正庚烷+邻二甲苯和正庚烷+三甲苯体系中呈正瓣。正庚烷+甲苯体系以色散力为主，而其他两种体系则以良好的几何拟合为主。

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引用次数: 0

Probing the molecular interactions in some promising biofuel blends (prenol, 1-hexanol, 1-octanol, and 1-decanol): volumetric, acoustic, and transport approach 探测一些有前途的生物燃料混合物（prenol， 1-己醇，1-辛醇和1-癸醇）中的分子相互作用：体积，声学和运输方法

Chemical Thermodynamics and Thermal Analysis

Pub Date : 2025-03-20 DOI: 10.1016/j.ctta.2025.100185

Ankush Bakshi, Chandani Sharma, Amit Kumar Sharma, Meena Sharma

The reported work involves measuring various thermo-physical properties such as density (

ρ

), speed of sound (

u

), viscosity (

η

), and refractive index (

n_{D}

) of some pure potential/promising biofuels (prenol, 1-hexanol, 1-octanol, and 1-decanol) and blends of prenol with these over the entire range of mole fraction from temperature T = (298.15 to 323.15) K and at 0.1MPa pressure making use of an Anton Paar vibrating U-tube density and sound velocity meter (DSA 5000 M) and Abbemat refractometer respectively. The collected thermo-physical data has been employed to compute various deviational and excess properties such as isentropic compressibility (

κ_{s}

), deviation in isentropic compressibility (

Δ κ_{s}

), deviation in refractive index (

Δ n_{D}

), deviation in viscosity (

Δ η

), excess molar volume (

V_{m}^{E}

), and excess Gibb's free energy of activation of viscous flow

(Δ G^{* E})

. Correlation of all the excess and deviational properties with composition has been made with the help of the Redlich-Kister type polynomial equation and standard deviation has been ascertained. Moreover, the temperature and composition dependence of these properties has also been analysed. The present work has been taken up for analysing the nature of interactions and structural effects prevalent between these blends and the collected thermo-physical data can be employed in the fields of designing and developing bio-based diesel fuels.

报告的工作涉及测量一些纯潜在/有前途的生物燃料(prenol， 1-己醇，1-辛醇，在温度T = (298.15 ~ 323.15) K和压力为0.1MPa的整个摩尔分数范围内，分别使用安东帕振动u型管密度声速计（DSA 5000 M）和阿贝马特折射仪对戊醇和癸醇的共混物进行了测定。利用收集到的热物理数据计算了各种偏离和超额性质，如等熵压缩率（κs）、等熵压缩率偏差（Δκs）、折射率偏差（ΔnD）、粘度偏差（Δη）、过量摩尔体积（VmE）和粘性流动激活的过量吉布自由能（ΔG*E）。利用Redlich-Kister型多项式方程，确定了所有多余和偏离性质与组分的关系，并确定了标准偏差。此外，还分析了这些性质对温度和成分的依赖关系。目前的工作是分析这些混合物之间普遍存在的相互作用和结构效应的性质，所收集的热物理数据可用于设计和开发生物基柴油燃料领域。

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引用次数: 0

Mechanism analysis and chemical equilibrium modelling for liquid phase glycerol hydrogenolysis 液相甘油氢解的机理分析及化学平衡模型

Chemical Thermodynamics and Thermal Analysis

Pub Date : 2025-03-18 DOI: 10.1016/j.ctta.2025.100186

Martín N. Gatti , Federico M. Perez , Gerardo F. Santori , Francisco Pompeo

In this work, the chemical equilibrium of the glycerol (GLY) hydrogenolysis in the liquid phase was studied from the mechanism of the CO and CC bond cleavage and hydrogenation reactions using the commercial simulator UniSim Design ® in the range T = 423–533 K, P = 4–10 MPa and molar ratios H₂/reactant = 0.4–2. The equilibrium constants were calculated from the Gibbs free energy, enthalpy and entropy of the reactions involved, employing the group contribution method to estimate the formation properties of the compounds. The results showed that the formation of EG through GLY and the hydrogenation reactions of acetol (AcOH) and 3-hydroxypropionaldehyde (3-HPA) to produce 1,2-propylene glycol (1,2-PG) and 1,3-propylene glycol (1,3-PG) respectively, are limited by thermodynamic equilibrium. For glycols, the formation of 1,2-PG is favored over that of 1,3-PG, and for propanols, the formation of 2-propanol (2-POH) is favored over that of 1-propanol (1-POH). In addition, the formation of EG from 1,2-PG is more feasible, and the formation of ethanol (EtOH) and methanol (MeOH) depend on alternative routes involving EG and 1,3-PG as intermediates, respectively. These results not only show good agreement with previously reported experimental data, but also provide relevant information for the design of bifunctional catalysts that are active and selective towards specific products in the liquid phase glycerol hydrogenolysis.

在T = 423-533 K, P = 4-10 MPa， H2/反应物摩尔比= 0.4-2的条件下，利用UniSim Design®商业模拟装置，从CO和CC键裂解和加氢反应机理出发，研究了甘油（GLY）在液相中的化学平衡。根据反应的吉布斯自由能、焓和熵计算平衡常数，采用基团贡献法估计化合物的生成性质。结果表明，通过GLY生成EG以及丙酮（AcOH）和3-羟基丙醛（3-HPA）加氢反应分别生成1,2-丙二醇（1,2- pg）和1,3-丙二醇（1,3- pg）受到热力学平衡的限制。对于乙二醇，1,2- pg的生成比1,3- pg的生成更有利；对于丙醇，2-丙醇（2-POH）的生成比1-丙醇（1- poh）的生成更有利。此外，1,2- pg生成EG更为可行，乙醇（EtOH）和甲醇（MeOH）的生成依赖于分别以EG和1,3- pg为中间体的替代途径。这些结果不仅与以往报道的实验数据吻合良好，而且为设计对液相甘油氢解中特定产物具有活性和选择性的双功能催化剂提供了相关信息。

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引用次数: 0

Thermodynamic study of the Cd3As2 and CdAs2 compounds by the electromotive force measurements 用电动势测量Cd3As2和CdAs2化合物的热力学研究

Chemical Thermodynamics and Thermal Analysis

Pub Date : 2025-03-17 DOI: 10.1016/j.ctta.2025.100184

D.M. Babanly , A.R. Aghayeva , E.N. Orujlu , E.J. Ahmadov , D.B. Tagiyev

Cadmium arsenides, particularly Cd₃As₂, have attracted considerable attention for their potential in advanced electronics, spintronics, and optoelectronics applications, owing to their exceptional charge transport properties and unique Dirac semimetal behavior. The combination of tunable bandgap and high carrier mobility makes them promising candidates for next-generation devices, including high-speed electronics and infrared photodetectors. Considering the inconsistent results in the available literature and the contemporary relevance of the research objects, a thermodynamic study of the α-Cd₃As₂ and CdAs₂ compounds in the 300–450 K temperatures range by low-temperature electromotive force method has been carried out in the present work. Measurements were performed using equilibrium samples taken from the CdAs₂ + As and α-Cd₃As₂ + CdAs₂ two-phase regions of the Cd-As system. The phase compositions of all samples were controlled using the powder X-ray diffraction method. The partial molar functions of cadmium in alloys, as well as the standard thermodynamic functions of the formation and standard entropies of the CdAs₂ and α-Cd₃As₂ compounds, were calculated. A comparative analysis of obtained results with literature has been carried out.

砷化镉，特别是Cd₃As₂，由于其特殊的电荷输运性质和独特的狄拉克半金属性质，在先进电子学、自旋电子学、光电子学等领域具有很大的应用潜力，受到了广泛的关注。可调带隙和高载流子迁移率的结合使它们成为下一代设备的有希望的候选者，包括高速电子设备和红外光电探测器。考虑到现有文献结果的不一致性和研究对象的当代相关性，本文采用低温电动势法对α-Cd3As2和CdAs2化合物在300-450 K温度范围内进行了热力学研究。利用Cd-As体系中CdAs2 + As和α-Cd3As2 + CdAs2两相区域的平衡样品进行测量。采用粉末x射线衍射法对样品的相组成进行了控制。计算了镉在合金中的偏摩尔函数，以及CdAs2和α-Cd3As2化合物形成的标准热力学函数和标准熵。将所得结果与文献进行了比较分析。

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引用次数: 0

Accelerating rate calorimetry: History, state of the art and perspectives 加速速率量热法：历史、现状和前景

Chemical Thermodynamics and Thermal Analysis

Pub Date : 2025-03-07 DOI: 10.1016/j.ctta.2025.100182

Jiong Ding , Kaixuan Liu , Chenyu Xu , Jiaming Li , Xu Yan , Jinchao Liang , Meng Feng , Arcady A. Kossoy , Jinxin Xu , Dongfang Hu

Accelerating Rate Calorimetry (ARC) is a crucial technique for studying chemical reaction kinetics assessing and thermal hazards. In this review article, the history of ARC development is introduced. The first section focuses on instrumentation. It elaborates This section expounds on the evolution of ARC, covering both classical methods and advanced techniques such as pressure tracking and power compensation. Recent advancements in ARC instrumentation are also highlighted, including improvements in varying thermal inertia, heat capacity measurement, heat dissipation correction, temperature range expansion, in-situ calibration, and performance evaluation. Given the growing application of ARC in lithium-ion batteries (LIBs), this section also discusses key features of ARC tailored for LIBs, such as versatile testing modes and the ability to accommodate larger sample sizes. The second section addresses kinetics. It reviews the progress of both model-fitting and model-free kinetic approaches, providing insights into their applications and advancements in the field. The third section explores applications. It introduces the use of ARC in studying thermal behaviors, chemical process safety, and lithium-ion batteries. These applications demonstrate the versatility and importance of ARC in various domains. Finally, the review concludes with future perspectives, emphasizing the need to consider temperature gradients, further advancements in kinetic approaches, and the extension of ARC applications to new areas.

加速量热法（ARC）是研究化学反应动力学、评价和热危害的一项重要技术。本文综述了ARC的发展历史。第一部分重点介绍工具。本节阐述了电弧的演变，涵盖了经典的方法和先进的技术，如压力跟踪和功率补偿。ARC仪器的最新进展也得到了强调，包括在变热惯性、热容测量、散热校正、温度范围扩展、原位校准和性能评估方面的改进。鉴于ARC在锂离子电池（lib）中的应用越来越多，本节还讨论了为锂离子电池量身定制的ARC的关键特性，例如通用测试模式和适应更大样本量的能力。第二部分讨论动力学。它回顾了模型拟合和无模型动力学方法的进展，提供了它们在该领域的应用和进展的见解。第三部分探讨应用程序。它介绍了ARC在研究热行为、化学过程安全性和锂离子电池中的应用。这些应用证明了ARC在各个领域的多功能性和重要性。最后，总结了未来的展望，强调需要考虑温度梯度、动力学方法的进一步进展以及ARC应用的新领域。

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引用次数: 0

Thermodynamic calculation studies on oil composition and water presence effect on the minimum miscibility pressure of the CO2/two-components oil system 热力学计算研究了油的组成和水的存在对CO2/双组分油体系最小混相压力的影响

Chemical Thermodynamics and Thermal Analysis

Pub Date : 2025-03-05 DOI: 10.1016/j.ctta.2025.100183

Hangyu Zang, Zeguang Dong, Zhongwen Zhang, Yingge Li, Dongxing Du

Minimum Miscibility Pressure (MMP) is a key parameter for guiding the CO₂ Enhanced Oil Recovery (EOR) as well as carbon geological storage applications. In this work, a thermodynamic calculation study is performed concerning the oil composition and the water presence effect on the MMP properties of the CO₂/multicomponent oil system under various temperatures. Two-components oils with different n-C₁₄H₃₀ and n-C₁₉H₄₀ ratios at 7:3, 6:4, 5:5, 4:6 and 3:7, are employed to reveal the oil composition effect on MMPs of CO₂/oil system. Via introducing saturated water into CO₂, the effect of water presence on MMPs of the CO₂/oil system is studied as well. Thermodynamic calculation results show the MMP of the CO₂/two-components oil systems increases from 8.5 MPa to 9.8 MPa, 10.1 MPa to 11.2 MPa, 11.6 MPa to 12.6 MPa, 12.9 MPa to 13.8 MPa, and 14.2 MPa to 15.0 MPa, together with the increasing portion of the heavier C₁₉ oil component from 30 % to 70 % at various temperatures of 40 °C, 50 °C, 60 °C, 70 °C and 80 °C, respectively. Calculation results also reveal the presence of the water component would reduce the MMPs of the CO₂/oil system by 0.2–0.8 MPa compared with the water absence case in the studied oil component and temperature conditions. In particular, the water presence effect on MMP reduction is more significant for the oils with higher portion of heavy components.

最小混相压力（MMP）是指导二氧化碳提高采收率（EOR）和碳地质封存应用的关键参数。在这项工作中，热力学计算研究了在不同温度下，油的组成和水的存在对CO2/多组分油体系的MMP性能的影响。采用不同n-C14H30和n-C19H40比为7:3、6:4、5:5、4:6和3:7的双组份油品，研究油品组成对CO2/油体系MMPs的影响。通过将饱和水引入到CO2中，研究了水的存在对CO2/油体系MMPs的影响。热力学计算结果表明，在40℃、50℃、60℃、70℃和80℃温度下，CO2/双组分油体系的MMP分别从8.5 MPa增加到9.8 MPa、10.1 MPa增加到11.2 MPa、11.6 MPa增加到12.6 MPa、12.9 MPa增加到13.8 MPa和14.2 MPa增加到15.0 MPa，较重C19油组分的比例分别从30%增加到70%。计算结果还表明，在研究的油组分和温度条件下，与无水情况相比，水组分的存在会使CO2/油体系的MMPs降低0.2 ~ 0.8 MPa。特别是对于重质组分含量较高的油，水存在对MMP还原的影响更为显著。

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引用次数: 0

Modeling the density of chlorinated brines with nonlinear multivariate regressions 用非线性多元回归模拟氯化盐水的浓度

Chemical Thermodynamics and Thermal Analysis

Pub Date : 2025-03-03 DOI: 10.1016/j.ctta.2025.100181

Mauricio Sepúlveda , Thierry Bertrand De Saint Pierre Sarrut , Andrés Soto-Bubert , Rashmi Bhardwaj , Roberto Acevedo

There is still no conclusive or definitive model for calculating brine density. The soft computing models that have been published are black boxes that do not allow us to observe the relationships of attributes or generalize results in new brine. Nevertheless, some techniques enable modeling "interpretable" regressions for multivariate and nonlinear data. These include Symbolic Regression, M5P trees, and the MARS method. In this paper, a generic regression is developed for each technique, using published density data for NaCl, KI, KCl, MgCl₂, SrCl₂, and CaCl₂ brines. The results show that all obtained models have a %AAD lower than 0.72 % in test data. Although this result is less accurate than published ones, it is offset by the automatic generation, the models' simplicity, and their ability to be used in new untrained brine, such as Na₂SO₄, NaHCO₃, and AlCl₃. The residual of the generated regressions is studied, concluding that the models still must incorporate new attributes. The regression models confirm a nonlinear relationship between the data attributes. An intercept is observed in them, which is similar between the models. A temperature variable shows a relationship with a significant tendency towards linearity and inverse with respect to density, which differs from that indicated in several publications. Similarly, pressure shows a linear and positive behavior with a small influence in magnitude. Finally, the salt molar weight attribute interacts strongly with the molality and temperature attributes, presenting the most complex expressions. A comparison with a physicochemical model (Laliberté) was made. Despite the latter showing better performance, advantages are observed in the new regressions. It is concluded that it is possible to generate nonlinear multivariate density regressions for single-component brines and to deduce the behavior of the variables from these models. This model could be illustrative and useful as a basis for future rigorous formulations of single-component brine.

目前仍没有计算盐水密度的结论性或确定性模型。已经发表的软计算模型是黑盒子，不能让我们观察属性之间的关系，也不能推广新盐水的结果。然而，一些技术可以对多变量和非线性数据进行“可解释”回归建模。这些方法包括符号回归、M5P树和MARS方法。在本文中，使用已发表的NaCl、KI、KCl、MgCl2、SrCl2和CaCl2盐水的密度数据，为每种技术开发了通用回归。结果表明，所得模型的AAD均低于0.72 %。虽然这一结果不如已发表的结果准确，但它被自动生成、模型的简单性以及它们在新的未经训练的盐水（如Na2SO4、NaHCO3和AlCl3）中使用的能力所抵消。研究了生成的回归的残差，得出模型仍然必须包含新属性的结论。回归模型证实了数据属性之间的非线性关系。在它们之间观察到一个截距，这在模型之间是相似的。温度变量与密度有显著的线性和反比趋势，这与若干出版物中所指出的情况不同。同样，压力表现为线性和正的行为，在量级上影响很小。最后，盐的摩尔质量属性与摩尔浓度和温度属性相互作用强烈，表现出最复杂的表达式。与物理化学模型（lalibert）进行了比较。尽管后者表现出更好的性能，但在新的回归中观察到优势。结果表明，单组分盐水可以产生非线性多元密度回归，并从这些模型中推导出变量的行为。该模型可以作为未来严格的单组分卤水配方的基础，具有说明性和实用性。

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引用次数: 0

Refractive indices of binary mixtures of diglycolamine - water at various temperatures 二乙醇胺-水二元混合物在不同温度下的折射率

Chemical Thermodynamics and Thermal Analysis

Pub Date : 2025-02-28 DOI: 10.1016/j.ctta.2025.100179

Eduardo I. Concepción

In this work, the refractive indices n_D, refractive index deviations Δ n_D, molar refractions R_m and excess molar refractions R^E_m were determined over the full range of compositions for the Diglycolamine-water binary mixture. Experimental measurements of these properties were carried out at atmospheric pressure and at temperatures ranging from 293.15 to 333.15 K. Excess molar refractions R^E_m and refractive index deviations Δ n_D have been fitted to the polynomial Redlich-Kister equation. The refractive indices have been compared with those predicted by the mixing rules proposed by: Lorentz-Lorenz (L-L), Gladstone- Dale (G-L), Eykman (E), Arago-Biot (A-B), Eyring-John (E-J), Bruggeman (B), and Oster (OS), in order to verify their validity for the Diglycolamine-water binary system. The experimental values of the refractive indices agree well with all the previous relationships, with the relationship of Oster (OS) and Gladstone-Dale (G-L) with which better results are obtained.

在这项工作中，测定了折射率nD，折射率偏差Δ nD，摩尔折射率Rm和过量摩尔折射率REm在整个组成范围内的二乙醇胺-水二元混合物。这些性质的实验测量是在大气压力和293.15至333.15 K的温度范围内进行的。多余的摩尔折射REm和折射率偏差Δ nD已拟合到多项式Redlich-Kister方程。并与Lorentz-Lorenz （L-L）、Gladstone- Dale （G-L）、Eykman (E)、Arago-Biot （A-B）、Eyring-John （E- j）、Bruggeman (B)和Oster （OS）提出的混合规则预测的折射率进行了比较，以验证其对二甘醇-水二元体系的有效性。折射率的实验值与之前的所有关系都很吻合，其中Oster （OS）和Gladstone-Dale （G-L）关系得到了较好的结果。

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引用次数: 0

Behavior of polyimides based on bicyclo[2.2.2]oct-7-ene-2,3,5,6-tetracarboxylic dianhydride under thermal treatment 基于双环[2.2.2]辛-7-烯-2,3,5,6-四羧基二酐的聚酰亚胺的热处理行为

Chemical Thermodynamics and Thermal Analysis

Pub Date : 2025-02-28 DOI: 10.1016/j.ctta.2025.100180

Petr Sysel , Pavla Nekvapilová , Jakub Havlín

This study investigated the preparation and thermal behavior of the polyimide based on the nonaromatic bicyclo[2.2.2]oct‑7-ene-2,3,5,6-tetracarboxylic dianhydride and aromatic 4,4´-(1,4-phenylenediisopropylidene)bisaniline. A significantly greater mass loss was detected in the nitrogen atmosphere than in the air atmosphere by using an isothermal thermogravimetric analysis of this product at 375 °C. This loss in nitrogen was reduced when approximately 1 wt% of the radical inhibitor 2,6-di‑tert-4-methylphenol was added to the polymer, whereas in the case of using an atmosphere containing oxygen, which is one from the most effective radical inhibitors, the presence of 2,6-di‑tert-4-methylphenol had practically no effect. This finding supports the application of a retro Diels–Alder reaction during the decomposition of the structure coming from bicyclo[2.2.2]oct‑7-ene-2,3,5,6-tetracarboxylic dianhydride including radical formation as intermediate products at temperatures above 350 °C, whereby the present oxygen inhibits this process very effectively. The products formed during thermal attack were analyzed via a combination of dynamic thermogravimetry with infrared spectroscopy. Some aspects of fully aromatic polyimides based on 4,4´-oxydiphthalic anhydride and 4,4´-(1,4-phenyleneisopropylidene)bisaniline were compared.

研究了以非芳香族双环[2.2.2]oct - 7- 2,3,5,6-四羧基二酐和芳香族4,4′-（1,4-苯基二异丙基）双苯胺为原料的聚酰亚胺的制备及其热性能。在375°C的等温热重分析中，在氮气气氛中检测到的质量损失明显大于在空气气氛中。当在聚合物中加入约1wt %的自由基抑制剂2,6-二叔-4-甲基苯酚时，氮的损失减少，而在使用含氧的气氛的情况下，这是最有效的自由基抑制剂之一，2,6-二叔-4-甲基苯酚的存在几乎没有影响。这一发现支持了在温度高于350°C的情况下，在双环[2.2.2]oct - 7-烯-2,3,5,6-四羧酸二酐的结构分解过程中，包括自由基形成作为中间产物的反向diols - alder反应的应用，其中存在的氧气非常有效地抑制了这一过程。采用动态热重法和红外光谱相结合的方法对热攻产物进行了分析。比较了以4,4′-二邻苯二酸酐和4,4′-（1,4-苯异丙基）双苯胺为原料的全芳香族聚酰亚胺的某些性能。

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