Iranian Journal of Chemical Engineering, Vol. 21, No. 1, 3-16, (2024) * Corresponding author: gabriela.lisa@academic.tuiasi.ro 3 Iranian Journal of Chemical Engineering pISSN: 1735-5397 eISSN: 2008-2355 Journal Homepage: www.ijche.com Experimental Studies of Surface Tensions for Binary and Ternary Systems of Benzyl Alcohol, N-Hexanol and Water. Modeling with Neural Networks Iuliana Bîrgăuanu 1 , Cătălin Lisa 1 , Alexandra Bargan 2 , Silvia Curteanu 1 , Gabriela Lisa *1 1 Gheorghe Asachi Technical University, Faculty of Chemical Engineering and Environmental Protection “Cristofor Simionescu”, 73 Prof.dr.doc. D. Mangeron Street, 700050 Iaşi, Romania 2 Petru Poni Institute of Macromolecular Chemistry of Iaşi, 41A Aleea Gr. Ghica Voda, 700487 Iasi, Romania ARTICLE INFO ABSTRACT Article type: Research article The design of installations in the chemical industry requires the knowledge of the thermodynamic properties of liquid mixtures. In the absence of experimental data, accurate predictive methods are needed. In this work, refractive index and surface tension, at different temperatures and atmospheric pressure, are experimentally determined for the binary and ternary systems of benzyl alcohol, n-hexanol and water, which are studied less in literatures.. Two models were developed to have excess surface tension corelate composition, normalized temperature and refractive index. The statistical processing of the experimental data with the multiple linear regression method allowed the development of a model of which, in the validation stage, the correlation coefficient was 0.9086 and the standard deviation was 4.36. With the best performing neural model, a correlation coefficient of 0.9727 and a standard deviation of 2.14 were obtained in the validation stage. DOI: 10.22034/ijche.2024.446235.1524 URL: https://www.ijche.com/article_194251.html Article history: Received: 2024-02-29 Revised: 2024-04-03 Accepted: 2024-04-17 Available online: 2024-04-17 Keywords: Excess thermodynamic properties, Benzyl alcohol, N-hexanol, Water, Surface tension, Refractive index 1. Introduction A good knowledge of the thermodynamic properties of liquid systems [1-14] is very important in engineering, as they lead to obtaining important experimental data for the design of distillation separation plants [15, 16]. The specialized literature reveal the fact that there is no data on the surface tension and refractive index of the binary systems of benzyl alcohol - n-hexanol, benzyl alcohol - water and the ternary system of benzyl alcohol - n-hexanol - water. Azizian and Bashavard [7] experimentally determined the surface tension for binary mixtures of benzyl alcohol - linear alcohols (1-propanol, 2-propanol, 1-butanol, 2- butanol, 1-pentanol, and 2-pentanol) at the