Pure-component vapor pressures using UNIFAC group contribution

1981 ◽  
Vol 20 (3) ◽  
pp. 239-246 ◽  
Author(s):  
Torben Jensen ◽  
Aage Fredenslund ◽  
Peter Rasmussen
Keyword(s):  
Pure Component ◽  
Group Contribution ◽  
Vapor Pressures

Correlation of pure component Gibbs energy. Using UNIFAC group contribution

AIChE Journal ◽  
1979 ◽  
Vol 25 (1) ◽  
pp. 203-205 ◽  
Author(s):  
Aage Fredenslund ◽  
Peter Rasmussen
Keyword(s):  
Gibbs Energy ◽  
Pure Component ◽  
Group Contribution

A Group-Contribution Method for Predicting Pure Component Properties of Biochemical and Safety Interest

2004 ◽  
Vol 43 (19) ◽  
pp. 6253-6261 ◽  
Author(s):  
Emmanuel Stefanis ◽  
Leonidas Constantinou ◽  
Costas Panayiotou
Keyword(s):  
Pure Component ◽  
Group Contribution ◽  
Group Contribution Method

A new Corresponding-States Group-Contribution method (CSGC) for estimating vapor pressures of pure compounds

1994 ◽  
Vol 101 ◽  
pp. 101-119 ◽  
Author(s):  
Ping Li ◽  
Pei-Sheng Ma ◽  
Shou-Zhi Yi ◽  
Zhi-Gang Zhao ◽  
Lin-Zi Cong
Keyword(s):  
Corresponding States ◽  
Group Contribution ◽  
Vapor Pressures ◽  
Group Contribution Method ◽  
Pure Compounds

Group-contribution based estimation of pure component properties

2001 ◽  
Vol 183-184 ◽  
pp. 183-208 ◽  
Author(s):  
Jorge Marrero ◽  
Rafiqul Gani
Keyword(s):  
Pure Component ◽  
Group Contribution

Equilibrium Vapor Cell for Quantitative IR Absorbance Measurements

1996 ◽  
Vol 50 (10) ◽  
pp. 1307-1313 ◽  
Author(s):  
Paul E. Field ◽  
Roger J. Combs ◽  
Robert B. Knapp
Keyword(s):  
Aqueous Solutions ◽  
Gas Flow ◽  
Pure Component ◽  
Organic Solutes ◽  
Vapor Pressures ◽  
Water Solvent ◽  
Beer's Law ◽  
Solution Preparation ◽  
Beer’S Law

Infrared absorbance measurements through a gas flow cell are made with the closed-loop circulation of vapor/air mixtures equilibrated with the use of temperature-regulated aqueous solutions. Constant reproducible vapor pressures of organic solutes are established with the equilibrated aqueous solutions. The water solvent depresses the vapor pressure of the pure organic solutes of methanol, ethanol, isopropanol, acetone, and methyl ethyl ketone (MEK). Knowledge of the solution liquid mole fractions, the pure component vapor pressures, and the Wilson coefficients permits determination of the solute vapor pressures to within 2% accuracy. Reliable aqueous solution preparation requires only the correct weighings of pure constituent materials before mixing to achieve the targeted solute liquid mole fractions. Absorbances are measured for four of the five solutes over a range of seven concentrations and for MEK over four concentrations. These concentrations show the absorbance region of adherence to Beer's law with an experimental precision of approximately ±2% for the solutes studied. Absorptivities that are calculated from the Beer's law slope are compared to the available infrared absorbance data.

scholarly journals A predictive group-contribution model for the viscosity of aqueous organic aerosol

2019 ◽  
Author(s):  
Natalie R. Gervasi ◽  
David O. Topping ◽  
Andreas Zuend
Keyword(s):  
Citric Acid ◽  
Dicarboxylic Acids ◽  
Organic Aerosol ◽  
Thermodynamic Activity ◽  
Pure Component ◽  
Group Contribution ◽  
Organic Mixtures ◽  
Wide Range ◽  
Group Contribution Model ◽  
Mixture Viscosity

Abstract. The viscosity of primary and secondary organic aerosol (SOA) has important implications for the processing of aqueous organic aerosol phases in the atmosphere, their involvement in climate forcing, and transboundary pollution. Here we introduce a new thermodynamics-based group-contribution model, which is capable of accurately predicting the dynamic viscosity of a mixture over several orders of magnitude (~ 10−3 to > 1012 Pa s) as a function of temperature and mixture composition, accounting for the effect of relative humidity on aerosol water content. The mixture viscosity modelling framework builds on the thermodynamic activity coefficient model AIOMFAC (Aerosol Inorganic–Organic Mixtures Functional groups Activity Coefficients) for predictions of liquid mixture non-ideality, including liquid–liquid phase separation, and the calorimetric glass transition temperature model by DeRieux et al. (2018) for pure-component viscosity values of organic components. Comparing this new model with simplified modelling approaches reveals that the group-contribution method is the most accurate in predicting mixture viscosity, although accurate pure-component viscosity predictions (and associated experimental data) are key and one of the main sources of uncertainties in current models, including the model presented here. Nonetheless, we find excellent agreement between the viscosity predictions and measurements for systems in which mixture constituents have a molar mass below 350 g mol−1. As such, we demonstrate the validity of the model in quantifying mixture viscosity for aqueous binary mixtures (glycerol, citric acid, sucrose, and trehalose), aqueous multicomponent mixtures (citric acid + sucrose and a mixture of nine dicarboxylic acids), and aqueous SOA surrogate mixtures derived from the oxidation of α-pinene, toluene, or isoprene. We also use the model to assess the expected change in SOA particle viscosity during idealized adiabatic air parcel transport from the surface to higher altitudes within the troposphere. This work demonstrates the capability and flexibility of our model in predicting the viscosity for organic mixtures of varying degrees of complexity and its applicability for modelling SOA viscosity over a wide range of temperatures and relative humidities.

scholarly journals Vapor pressures of substituted polycarboxylic acids are much lower than previously reported

2013 ◽  
Vol 13 (13) ◽  
pp. 6647-6662 ◽  
Author(s):  
A. J. Huisman ◽  
U. K. Krieger ◽  
A. Zuend ◽  
C. Marcolli ◽  
T. Peter
Keyword(s):  
Vapor Pressure ◽  
Pure Component ◽  
Vapor Pressures ◽  
Estimation Model ◽  
Polycarboxylic Acids ◽  
Empirical Correction ◽  
Tartaric Acids ◽  
Tartronic Acid ◽  
High Vapor ◽  
Primary Focus

Abstract. The partitioning of compounds between the aerosol and gas phase is a primary focus in the study of the formation and fate of secondary organic aerosol. We present measurements of the vapor pressure of 2-methylmalonic (isosuccinic) acid, 2-hydroxymalonic (tartronic) acid, 2-methylglutaric acid, 3-hydroxy-3-carboxy-glutaric (citric) acid and DL-2,3-dihydroxysuccinic (DL-tartaric) acid, which were obtained from the evaporation rate of supersaturated liquid particles levitated in an electrodynamic balance. Our measurements indicate that the pure component liquid vapor pressures at 298.15 K for tartronic, citric and tartaric acids are much lower than the same quantity that was derived from solid state measurements in the only other room temperature measurement of these materials (made by Booth et al., 2010). This strongly suggests that empirical correction terms in a recent vapor pressure estimation model to account for the inexplicably high vapor pressures of these and similar compounds should be revisited, and that due caution should be used when the estimated vapor pressures of these and similar compounds are used as inputs for other studies.

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