有机类物质蒸气压数学模型的研究

通过对有机类化合物蒸气压估算方法的研究,通过一些手册或软件中的数据库,来查找有机类化合物蒸气压的物性数据。运用一定的数学分析方法和Origin及Matlab软件对已有的物性数据进行回归,得到有一定精度的关联式。从而减少使用者查找数据的工作量,提高估算数据的准确度,得到较精确的数据,为生产、设计提供依据。     

低饱和蒸气压的静态法实验研究及误差修正

针对物质低饱和蒸气压数据大量缺乏给化工生产、设计带来不便的现状,基于直接静态法研究了一种实验测量方法,实现了0~100℃温度范围内物质0~133 Pa低蒸气压数据的自动测量。以三甘醇、1-十二烯2种试样为对象进行实验,并针对实验本体从设计上不可避免存在的空气残余及泄漏两项误差设计空样实验以获取其误差修正量,通过在实验结果中剔除误差修正量的方法进行误差补偿,将补偿前、后的实验结果与文献标准值进行比较以确定补偿方法的有效性。实验结果表明:补偿前平均绝对误差为6.98 Pa,最大绝对误差为13.34 Pa,相对于现有静态法实验研究绝对误差显著减小,但相对误差较大;补偿后平均相对误差为7.3%,最大相对误差为10.1%,提高了静态法在低压范围的测量精度,同时为理论研究和工程应用提供了准确的低蒸气压数据。     

MMT饱和蒸气压测定与关联

采用活塞膨胀法测定甲基环戊二烯三羰基锰(MMT)在278.15-392.15K之间的饱和蒸气压数据。采用非线性回归的方法得到Antoine常数A,B,C的值分别为4.3164,1222.294,-1.2142,饱和蒸气压的计算与实验值之间的相对误差不超过3.0%;通过Clausius-Clapeyron方程计算得到甲基环戊二烯三羰基锰在278.15-392.15K之间的平均摩尔蒸发热为23555.22J/mol,常压沸点为529.10K。     

Origin 8.0软件在物理化学实验中的应用

以纯液体饱和蒸气压的测定和硝酸钾溶解热的测定两个物理化学实验的数据分析为例,介绍Origin 8.0软件在物理化学实验教学中的应用。Origin 8.0软件在液体饱和蒸气压的测定数据后处理过程中体现出简便的数据计算、线性拟合和图像处理功能;而在硝酸钾溶解热实验的数据处理过程则很好地体现了丰富的曲线拟合功能,得到了两个合适的拟合方程——Exp Dec2和Log3P1,方便了数据的进一步演算。     

263~373K温度区间2-氯-3,3,3-三氟丙烯饱和蒸气压的实验研究

采用静态法,测定了2-氯-3,3,3-三氟丙烯(HCFO-1233xf)的饱和蒸气压97个数据点,温度263.15~372.90 K,温度不确定度小于±2 mK,压力不确定度小于±1.2 kPa,并用Antoine方程lnP=A-B/(T+C)进行关联,确定了蒸气压方程的三个参数A、B、C的值分别为15.119、3070.575和7.198。Antoine方程计算得到的饱和蒸气压与实验数据吻合较好,相对误差均在±1%以内。通过Clausius—Clapeyron方程计算得到HCFO-1233xf在263.15~372.90 K的平均摩尔蒸发热为24363.31 J?mol-1,通过Antoine方程计算得到的常压沸点为285.22 K。     

松节油体系组分饱和蒸气压研究进展

本文综述了松节油体系组分的饱和蒸气压研究现状,根据松节油由双环单萜和倍半萜组成的特性,提出了适用于松节油体系组分饱和蒸气压的测定原理、测量方法、数据关联及估算方法。松节油体系组分是沸点相近的萜类同分异构体,难以分离得到纯度很高的松节油组分,利用稀溶液溶剂符合Raoult定律的原理,间接测定蒎烷、顺式蒎烷、对孟烷和长叶烯的饱和蒸气压。Antoine方程的三参数形式适用于松节油组分饱和蒸气压与温度的关联;对应态基团贡献法可应用于松节油组分饱和蒸气压数据的估算。     

四氧化二氮胶体饱和蒸气压的测试及分析

为了测定胶体四氧化二氮的饱和蒸气压,找出其在不同温度条件下的变化规律,采用静态法测试原理,自行设计建立了四氧化二氮胶体饱和蒸气压的测试装置,测得了常压下液体和胶体四氧化二氮的饱和蒸气压数据,结果表明,四氧化二氮体系成胶后比成胶前的饱和蒸气压略有降低,且温度越高其差值越大.从理论上分析了两种胶凝剂对四氧化二氮体系饱和蒸气压的影响作用,从而推导出了四氧化二氮胶体饱和蒸气压的理论计算公式,计算误差小于5%,可依据该公式对四氧化二氮胶体在不同温度条件下的饱和蒸气压进行估算.     

基于蒸气压下降法测定物质摩尔质量的实验研究

摩尔质量是物质的一个重要基本参数。物理化学实验中常用凝固点降低法测定物质的摩尔质量，但在实验过程中其凝固点不易判断。本文利用稀溶液饱和蒸气压下降的原理，设计了测定物质摩尔质量的方法和装置，实验原理清晰、操作简单。我们分别对尿素、蔗糖的水溶液和萘的环已烷溶液进行了实验测定，实验测得的尿素、蔗糖和萘的摩尔质量分别为58.1,352.7和121.5 g/mol,与理论值的相对误差分别为3.33%、3.03%和4.50%。饱和蒸气压下降法为测量物质的摩尔质量提供了一种简单的候选方法。     

化工和制药专业动态法和静态法测量水的饱和蒸气压实验的比较

化学物质的饱和蒸气压是化工、制药、冶炼等行业的基础理化参数之一.实验测量纯物质的饱和蒸气压是高校物化实验教学中的一个经典实验.大多数高校采用静态实验法.基于动态法和静态法两种方法的比较少见报道.通过比较动态法和静态法测量纯水的温度-压力实验数据,通过软件作图我们得到了两种方法水的摩尔汽化热值和沸点值.动态法简单而又不失测量精度,加深了化工和制药等工科专业大学生对基础物化实验认识和理解,值得在地方高校应用型本科专业推广试验.     

五种酯类化合物极微蒸气压的扭转法测定

<正> 引言 物质的饱和蒸气压是最重要的物性数据之一.在化工设计、生产与科学研究中,如农药、化肥的储存,香料的挥发速度,橡胶、塑料中增塑剂的有效寿命等,对有机酯类化合物低蒸气压数据要求迫切.由于测定难度以及数据准确性等问题,目前极微蒸气压的数据非常缺乏.测定方法主要有Knudsen隙透法和同位素示踪法,后者由于实验条件苛刻而很少     

Extension of EOS non-iterative methods to density calculations: Correlation of saturated molar volumes and heats of vaporization

Soave's direct calculation procedures for the vapor pressure of pure compounds with cubic equations of state (EOSs), have been extended to the calculation of phase densities at saturation for Peng-Robinson (PR) type EOSs. These universal relations have been used to propose EOS-based correlation methods for the pure compound saturated liquid and vapor molar volumes, at temperatures higher than the normal boiling point. The methods yield satisfactory results independently of the molecular nature of the chemical under consideration. The results for phase densities are used to correct the heats of vaporization predicted by the ZVPR-EOS. Complete relative error information is provided for calculated heats of vaporization and correlated vapor and liquid phase molar volumes for more than one hundred compounds of industrial interest.     

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。     

A new vapor pressure equation for pure substances

A new simple equation for prediction of vapor pressure of pure substances is proposed. The equation which has the Clausius-Clapeyron (C-C) equation form consists of three parameters: critical temperature, critical pressure and normal boiling point. Experimental data for organic and inorganic substances have been used to calculate equation parameters in the boiling point ranges from 169.45 to 457.55 K and critical temperature ranges from 282.75 to 699.15 K. Comparison of proposed equation estimation results with experimental data shows that the new equation has minor average error. The new equation is also 68 percent more accurate than the C-C equation     

Rapid measurements of boiling point and vapor pressure of short-chain triglycerides by thermogravimetric analysis

Temperature dependence of vapor pressure and the boiling points for tricaproin (Tcap) and tricaprylin (Tcpy) were measured by a new rapid thermogravimetric analysis (TGA) method. Results were in agreement with data from other references. The Clausius/Clapeyron model fitted Tcap and Tcpy vapor pressure data with errors of 6% or less for pressures ranging from ambient down to 20 mmHg. This agreement with the model suggests that the vapor of these compounds has a large degree of ideal gas behavior and that their vaporization enthalpies are nearly constant from 25 to 400°C. Comparable accuracy and precision were obtained with TGA and differential scanning calorimetry methods for the compounds tested; however, TGA plots had significantly straighter baselines, which made vapor pressure determinations more convenient.     

A vapor pressure equation for heavy compounds

A vapor pressure calculation procedure based on a lattice equation is applied to several compounds. Originally, the method was used to predict low vapor pressures of heavy hydrocarbons. In this work, the method is used at low vapor pressure for nonhydrocarbons, and a modified version is employed at high vapor pressure for n-alkanes. As the procedures require the knowledge of one vapor pressure datum only, they work in a predictive mode. Prediction for hydrocarbons is good and for nonhydrocarbons is poor. Prediction of n-alkanes high vapor pressure is good with an overall average relative absolute deviation under 6 percent.     

甲基二苯基乙氧基硅烷饱和蒸汽压测定与关联

通过减压精馏的方法得到高纯度的甲基二苯基乙氧基硅烷,使用精馏法测定了甲基二苯基乙氧基硅烷在0.04—23.03 kPa范围内的饱和温度数据。采用非线性回归方法,利用EVIEWS 5.0软件得到甲基二苯基乙氧基硅烷的Antoine常数A,B,C的值分别为7.026 9,2 372.59和181.47,安托尼方程计算出的饱和蒸汽压与实验数据的误差在0—5.56%之间,与文献值的误差不超过7.41。通过Clausius-Clapeyron方程计算得到甲基二苯基乙氧基硅烷在373.20—512.23 K范围内平均摩尔蒸发热为72 942.96 J/mol,常压沸点为556.20 K。     

Estimation of solid vapor pressures from supercritical CO2 + biomolecule systems using a PSO algorithm

A method to estimate the solid vapor pressures of biomolecules using a biologically deriver algorithm is presented. The solid vapor pressure is usually small for most solid compounds and in many cases available experimental techniques cannot be used to obtain accurate values. Therefore, estimation methods must be used to obtain these data. Five binary gas-solid phase systems of supercritical CO₂ + biomolecule containing caffeine, artemisinin, capsaicin, cholesterol, and β-carotene are considered in this study. Particle swarm optimization is used for minimize the difference between calculated and experimental solubility. Then, the solid vapor pressures of biomolecules are calculated from solubility data. The Peng-Robinson equation of state with the Wong-Sandler mixing rules are used to evaluate the fugacity coefficient on the systems. The results show that the method presented is reliable enough and can be used with confidence to estimate the solid vapor pressure of any organic biomolecule.     

The effect of temperature and humidity on the long-term performance of poly(butylene terephthalate) compounds

A model was developed that closely fits new and previously published test data for the aging of poly(1,4-butylene terephthalate) (PBT) compounds under conditions of elevated temperature and high relative humidity. The model equation, stated in terms of absolute temperature and water vapor partial pressure, allows extrapolation of accelerated aging data to ambient conditions that prevail in realistic applications of the materials. For practical reasons, the water vapor partial pressure is preferred as a model variable over relative humidity, although it is shown that both variables are equivalent in a formal sense.     

热重分析法测定氟唑活化酯的饱和蒸气压

基于自由蒸发过程的Langmuir关系,利用梅特勒-托利多TGA/DSC1/1100LF型热重分析仪,建立采用热失重法快速测定化合物氟唑活化酯的低温饱和蒸气压的方法。采取阶梯升温方式,先在测定温度范围内较低的温度点恒温一定时间,获得满足测定精度所需要的质量损失,升温到下一温度进行测定,直至所需的最高温度。氟唑活化酯25℃时的饱和蒸气压为3.31×10^(-4)Pa。结果表明,利用热重法测定化合物的较低蒸气压,是传统蒸气压测定方法的很好补充,其结果与文献数据符合较好。测定方法系统误差低于1%。