改进对应态基团贡献法用于纯物质偏心因子估算

将对应态基团贡献法(CSGC)提出的拟临界性质应用于Lee-Kesler方程,提出新的纯物质偏心因子ω估算方程(CSGC-LK方程),对包括烷烃、烯烃、炔烃、卤代烷烃、环烷烃、环烯烃、二烯烃、醇、醚、酮、酸与酸酐、醛、酯、含硫化合物、含氮化合物、含氧多基化合物、芳烃、卤代苯和酚等20类376种物质偏心因子数据采用非线性最小二乘法进行关联,得到CSGC-LK方程的8个常数值和69种基团贡献参数值,ω总平均相对误差为5.47%。为进一步考察CSGC-LK方程的预测精度和适用范围,对7种未参加回归物质的偏心因子进行了预测,ω总平均误差为3.46%,预测精度良好。     

用对应状态基团贡献法估算纯物质的饱和蒸汽压

提出一种估算纯物质饱和蒸汽压的新对应状态基团贡献法———CSGC -PC方程 ,用 2 6 1种物质 1177个数据回归出了方程的参数 ,并得到了 94个基团对临界温度和临界压力的贡献值。回归的平均相对误差为 1.81%。该方程仅需物质的正常沸点Tb,对缺乏实验临界数据的热敏性物质和大分子物质尤其适用。     

神华煤液化油窄馏分假临界性质的研究(Ⅰ) 假临界温度

对神华煤进行煤炭直接液化实验,将300℃之前的液化生成油切割成8个窄馏分,利用基团贡献法计算得到窄馏分的假临界温度随蒸馏温度升高而升高,且符合线性方程Tc=435.4+1.298t.采用6种不同关联式计算得到的煤液化油窄馏分的假临界温度与基团贡献法的估算值有较好的一致性,相对误差在5%之内,其中采用Watanasiri关联式和日本NEDO法的相对误差在2%之内.     

用基团贡献法估算烃类的沸点和熔点

本文提出了烃类沸点和熔点的基团贡献法估算公式,探讨了烃类基团的划分和烯烃顺反式结构的校正,拟合得出37个烃类基团的贡献值.沸点和熔点估算的平均百分相对偏差分别为1.11和10.55,明显优于目前文献推荐的loback 法.     

基团贡献法分子设计研究的进展

利用基团贡献法可预测化合物的性质,还能用于化合物的计算机辅助分子设计(CAMD).本文论述了基于基团贡献法CAMD的基本原理,以及在溶剂和聚合物等领域分子设计的应用,对分子设计的计算方法也作了简单的介绍.随着绿色溶剂和新型聚合物材料需求的增加,基团贡献法CAMD将大有应用前景.     

预测复杂高沸点重质油馏分平均沸点的基团贡献法

采用超临界流体萃取分馏技术,在较低温度下(<250℃)将重质油分离成多个窄馏分,结合物性及¹H-NMR、¹³C-NMR分析确定其化学结构,构建重质油馏分的等价分子模型,并采用高温模拟蒸馏测定馏分的平均沸点至950K.以Rarey提出的预测纯化合物的基团贡献沸点新方法为基础,依据重质油馏分结构参数确定了12种基团类型,原模型基团贡献值保持不变.用原模型预测俄罗斯渣油馏分沸点,与C₅₀以下的馏分沸点实验值有较好的一致性,但对更重馏分误差大.对原模型沸点与总原子数的变化关系进行了修正,修正模型对两种不同基属原油的常压渣油和减压渣油馏分的沸点预测与实验值的平均误差为1.4%,同时能较准确估算高沸点正构烷烃的沸点,进一步验证了重质油馏分结构模型的合理性.结合改进的基团贡献法和超临界流体萃取分馏技术,可将重质油沸点预测延伸到1050K,碳原子数范围扩展到100个碳原子,为重质油馏分沸点估算提供了一种新的方法.     

瞬时法测定不稳定化合物的临界温度和临界压力

设计、安装了一套测定不稳定化合物的临界温度 (Tc)和临界压力 (pc)的毛细管瞬时法装置 ,以正戊烷 (n -C5H1 2 )、正己烷 (n -C6H1 4 )和 1 -庚烯 (1 -C7H1 4 )为标准试剂对装置的可靠性进行了校验 ,并测定了亚硝酸异戊酯、二烯丙基醚、二甲硫醚和烯丙基胺等 4种物质在不同停留时间 (τ)下的表观临界温度 (Tc,a)和表观临界压力 (pc,a) .停留时间最长为 2 0s,有效地控制了被测流体的热聚合和热分解 .采用线性外推方法得到了这些物质的Tc 和 pc.所有的数据除二甲硫醚外均为首次测定 .     

估算橡胶助剂溶解度参数用基团贡献值的研究

应用化合物的摩尔基团可加性原理，研究了估算橡胶助剂溶解度参数用的摩尔体积、摩尔内聚能、摩尔折射度和摩尔引力常数的基团贡献值。在现有文献的基础上，还扩充了２４种基团的１１０个贡献值。扩充后的基团贡献值，可分别用Ｆｅｄｏｒｓ，Ｌａｗｓｏｎ和Ｈａｎｓｅｎ法估算出迄今为止的大部分橡胶助剂的溶解度参数。     

估算有机物正常沸点的基团贡献法的研究进展

有机物的正常沸点是重要的物性数据之一。尽管文献中有很多化合物正常沸点的实验值,但一些物质的正常沸点不能由实验获得,可以通过建立数学模型来估算缺少的有机物正常沸点,其中基团贡献法是人们获得正常沸点的最重要研究方法。本文对估算有机物正常沸点的基团贡献法进行了综述。主要介绍了Joback法、C—G法、许文法、定位分布贡献法、元素和化学键法等方法的原理、优缺点及应用范围;并对这些方法进行简单的比较;最后指出了有机物正常沸点的基团贡献法的发展趋势。     

对应态基团贡献法(CSGC)估算有机物蒸汽压

通过引入拟临界性质的概念，将对应态原理与基团贡献方法相结合，提出一种新的物性估算方法－－对应态基团贡献法（Corresponding State Group Contribution,简称CSGC）。将其与Riedel方程相结合，提出新的蒸汽压估算方程（CSGC－RE方程），用于纯物质饱和蒸汽压的估算。经过对包括各类烃、含氧化合物、含氮化合物、含卤素化合物等20类349种物质5254个数据点的回归计算得到的87种基团的贡献参数值，总误差1．35％。为说明该方程的准确性，还给出了Riedel式、Lee-Kesler式以及Riedel-Plank-Miller式计算结果的比较。新模型既有对应态法简单的形式，又具有基团贡献法广泛的预测能力，仅需要物质极易获得的正常沸点数据，便可准确估算物质的蒸汽压，是一种十分有效的有机物物性估算方法。     

NEW GROUP-CONTRIBUTION CORRELATIONS FOR ESTIMATION OF CRITICAL PROPERTIES

New correlations based on group-contribution method for estimating critical properties have been proposed with con-tribution values of 67 groups.The new correlations have been examined by extensive comparison of the values calculatedwith the experimental data of 275 substanees.The average percent deviations of estimation of T_c,P_c and V_c are respective-ly 0.76,2.73 and 2.50 which are lower than those estimated by the Lydersen method and the Ambrose method chosenfor eomparision.     

A group-contribution correlation for predicting the acentric factors of organic compounds

A group-contribution correlation has been developed for the estimation of the acentric factors of organic compounds. The novelty of the proposed method is that it involves the use of only the structural information of the compounds. For the 219 substances considered in this study, the calculated results deviate from the literature values by an average error of 4.2%.     

纯物质临界参数估算方法的研究进展

纯物质的临界参数在描述流动相行为、预测物质性质、发展状态方程等方面都是非常重要的。临界参数的准确与否直接影响其它物性参数的估算结果。通过建立数学模型为缺少的临界参数进行预测估算,是人们获得临界参数的重要研究途径。本文对纯物质临界参数的估算方法进行了综述。主要介绍了其与其它物性相关联的估算方法、基团贡献法、基于液体状态方程的估算方法、定量结构性质关系法（QSPR法）等几类具有代表性的临界参数估算方法;并重点阐述了这些方法的原理、应用范围、优缺点及最近几年的进展情况;最后指出随着科学和计算机的快速发展,估算临界参数的方法也将不断完善和提高,具有更好的通用性和精确度,进而为化工流程模拟、工程设计计算、科研生产及应用研究提供更加可靠的数据。     

ESTIMATION OF HEAT OF VAPORIZATION OF PURE LIQUID AT ITS NORMAL BOILING TEMPERATURE

A new method is proposed to estimate the heat of vaporization of pure liquid at its normal boiling temperature. The properties required include the boiling temperature, critical temperature and critical pressure. For monohydric alcohol and monohydric organic acid, an adjusting-boiling-temperature strategy is proposed to reduce the calculation errors. The method is tested for 160 substances including many groups of compounds. The results show that the proposed method is better than the literature methods, especially for monohydric alcohol and monohydric acid.     

ESTIMATION OF HEAT OF VAPORIZATION OF PURE LIQUID AT ITS NORMAL BOILING TEMPERATURE

A new method is proposed to estimate the heat of vaporization of pure liquid at its normal boiling temperature. The properties required include the boiling temperature, critical temperature and critical pressure. For monohydric alcohol and monohydric organic acid, an adjusting-boiling-temperature strategy is proposed to reduce the calculation errors. The method is tested for 160 substances including many groups of compounds. The results show that the proposed method is better than the literature methods, especially for monohydric alcohol and monohydric acid.     

ESTIMATION OF VAPOR PRESSURES OF ORGANIC NITROGEN AND SULFUR COMPOUNDS BY A GROUP-CONTRIBUTION METHOD

The group-contribution method for vapor pressures of hydrocarbons and organic compounds containing nitrogen or sulfur, based on the kinetic theory of fluids, is revised and extended to include new groups containing nitrogen or sulfur. Good representation is obtained for vapor pressure data in the region 1.30-270 kPa. The method may be used to estimate vapor pressures and enthalpies of vaporization for those organic fluids containing nitrogen or sulfur, where no experimental data are available.     

Artificial neural network for the prediction of physical properties of organic compounds based on the group contribution method

In the development and optimization of chemical processes involving the selection of organic fluids, knowledge of the physical properties of compounds is vital. In many cases, it is complex to find experimental measurements for all substances, so it becomes necessary to have a tool to predict properties based on the characteristics of the molecule. One of the most extensively used methods in the literature is the estimation by contribution of functional groups, where properties are calculated using the constituent elements of the molecule. There are several models published in the literature, but they fail to represent a wide variety of compounds with high accuracy and simultaneously maintain a low computational complexity. The aim of this work is to develop a prediction model for eight thermodynamic properties (melting temperature, boiling temperature, critical pressure, critical temperature, critical volume, enthalpy of vaporization, enthalpy of fusion, and enthalpy of gas formation) based on the group contribution methodology by implementing a multilayer perceptron. Here, 2736 substances were used to train the neural network, whose prediction capacity was compared with other reference models available in the literature. The proposed model presents errors ranging from 1% to 5% for the different properties (except for the melting point), which improves the reference models with errors in the range of 3%–30%. Nevertheless, a difficulty in the prediction of the melting point is detected, which could represent an inherent hindrance to this methodology.     

A GROUP-CONTRIBUTION METHOD INVOLVING SPECIFIC GRAVITY AS A PARAMETER FOR ESTIMATING CRITICAL TEMPERATURES

A new group-contribution method involving specific gravity as a parameter is proposed for predicting criticaltemperature.Being appliable to all kinds of organic compounds,it gives an average percent deviation of 0.88%for 93 compounds and is particularly useful to those substances for which the normal boiling points are stillunknown.     

A New Group Contribution Method based on Equation of State Parameters to Evaluate the Critical Properties of Simple and Complex Molecules

A new group contribution method to evaluate the critical properties (temperature, pressure and volume) is presented and applied to estimate the critical properties of biomolecules. Similar to other group contribution methods, the one proposed here divides the molecule into conveniently defined groups and evaluates the properties as the sum of the different contributions according to a specified model equation for each of the properties. The proposed method consists of a one‐step calculation that uses simple model equations and does not require additional data besides the knowledge of the structure of the molecule, except for isomers. For these substances the normal boiling temperature, the molecular mass and the number of atoms in the molecule are used to distinguish among isomers. The method is applicable to high molecular weight compounds, as most biomolecules and large molecules present in natural products.