Corresponding-States Model for the Correlation and Prediction of the Surface Tension of Silanes

Abstract

A new corresponding-states model for the calculation of the surface tension of silanes is proposed. It requires, as input properties, the critical point temperature, the minimum temperature at which one data for the surface tension is available, and the corresponding maximum value of this property. It includes two adjustable coefficients, which are calculated by considering the data available at the DIPPR database for 5 silanes. Then the model is applied to predict the surface tension values for other 31 silanes. Averaged absolute deviations below 12% are found for the 36 silanes, being below 5% for 33 of them. Results obtained by using the other five corresponding-states models available in the literature, one of them specifically designed for silanes, are also obtained. That proposed here gives clearly the best overall results.

Surface Tension for Silanes, Refrigerants, and Carboxylic Acids: Simple Corresponding State Correlations versus DIPPR Data

“…According to the results obtained, one term is enough to reproduce most of the DIPPR data available for silanes, carboxylic acids, and refrigerants accurately. The correlation proposed by Cachadiña et al for refrigerants, eq , contains two terms and can also be applied to silanes and carboxylic acids, the mean AAD being 3%. The correlation proposed by Cachadiña et al for acids, eq , contains two terms, and it gives poor results for refrigerants. It could be applied with accuracy only for some silanes but not in all cases. The correlation proposed by Yang et al . for silanes, eq , contains just one term and can be applied with accuracy for the three kinds of fluids mentioned.…”

“…In all previous cases, the proposed correlations contain at least two terms. Nevertheless, very recently, Yang et al 30 have shown that it is possible to obtain good results, at least for the family of silane fluids, using just a straightforward term as where T min is the lowest temperature at which a value of surface tension is available (for some fluids, it can be the temperature at the triple point) and σ( T min ) is the corresponding value. AADs between predicted values and those in DIPPR database 33 are below 5% for 33 out of 36 silanes liquids and below 12% for all silanes liquids considered.…”

“…), eqs 1 – 6 use a value of the surface tension as input, instead of these other properties, and they give significantly better results. 30 As it is known, some of the drawbacks of CSP models are that the behavior of surface tension at a low temperature is not taken into account and/or that the input properties used are not clearly related to the behavior of the surface tension. The new kind of CSP models, described by eqs 1 – 6 , is a more accurate and straightforward alternative when at least a value of the surface tension is known.…”

“…First, this kind of model has the advantage of not depending on the properties that could be unknown for some fluids or whose relationship with the surface tension is unknown. Moreover, their analytical expressions can be simpler than those given in classical CSP models. − ,− …”

“…Compared to the commonly used CSP correlations that contain other properties as inputs (acentric factor, boiling temperature, critical pressure, etc. ), eqs – use a value of the surface tension as input, instead of these other properties, and they give significantly better results . As it is known, some of the drawbacks of CSP models are that the behavior of surface tension at a low temperature is not taken into account and/or that the input properties used are not clearly related to the behavior of the surface tension.…”