Density and Viscosity for a Binary Mixture of cis-3-Hexenyl Formate, Butyl Acetate, trans-2-Hexenyl Acetate, and cis-3-Hexenyl Acetate with Ethanol at Several Temperatures Hiannie Djojoputro and Suryadi Ismadji* Department of Chemical Engineering, Widya Mandala Surabaya Catholic University, Kalijudan 37, Surabaya 60114, Indonesia The density and viscosity of binary mixtures cis-3-hexenyl formate (1) + ethanol (2), butyl acetate (1) + ethanol (2), trans-2-hexenyl acetate (1) + ethanol (2), and cis-3-hexenyl acetate (1) + ethanol (2) over the whole range of composition have been measured at three different temperatures (293.15 K, 303.15 K, and 313.15 K). The excess molar volume and viscosity deviation of these systems were also calculated, and the results were fitted to a well-known Redlich-Kister-type polynomial equation. Introduction In the flavor and fragrance industries, aliphatic and acrylic esters are important materials in manufacturing processes. 1 Most of the esters used here are acetates, whereas ethanol is the most common alcohol component. In addition to straight-chain saturated compounds, branched-chain compounds and unsaturated esters are also important within these industries. Studies of the thermodynamic behavior and physical properties of several esters in their binary mixtures have been performed, including ethyl valerate and hexyl acetate with 1-pentanol and 1-hexanol; 1 benzyl acetate, 2-ethyl- hexyl acetate, benzaldehyde, and pentyl acetate with 1-butanol and 1-pentanol; 2 methyl propanoate, methyl butanoate, ethyl propanoate, and ethyl butanoate with several hydrocarbon solvents; 3 ethyl acetate with several alcohols; 4 methyl butanoate with n-heptane, cyclooctane, n-octane, and 1-octanol; 5-7 ethyl acetate with aromatic hydrocarbons, alcohols, and water; 8-11 isopropyl acetate with an aromatic hydrocarbon; 12 acrylic esters with alco- hols; 13,14 butyl acetate and ethyl propionate with methanol and water. 15 However, investigations of the physical prop- erties of cis-3-hexenyl formate, butyl acetate, trans-2- hexenyl acetate, and cis-3-hexenyl acetate in a binary mixture with alcohol, especially ethanol, over a wide range of temperatures and compositions are still scarce and not available in the literature. Therefore, this study was undertaken to obtain reliable density and viscosity data for binary mixtures of these esters at 293.15 K, 303.15 K, and 313.15 K. Experimental Section Materials. High-purity and AR-grade samples of etha- nol, cis-3-hexenyl formate, butyl acetate, trans-2-hexenyl acetate, and cis-3-hexenyl acetate were purchased from Sigma-Aldrich Singapore. The purity of these chemicals was analyzed by gas chromatography (Shimadzu, GC-17A) using a flame ionization detector with a DB-5 column. Helium (high purity) was used as the carrier gas. The purity of these esters is 97.4% for cis-3-hexenyl formate, 99.7% for butyl acetate, and 98.9% for trans-2-hexenyl acetate and cis-3-hexenyl acetate. These esters were used without any further purification. The binary mixture samples were prepared by mass in airtight-stoppered glass bottles using a Mettler Toledo AE 240 balance with an uncertainty of (10 -5 g. The uncer- tainty of the mole fraction for each binary mixture is less than 0.0001. Density Measurements. Measurements of the densities of the pure components and the binary mixtures were carried out using a Mettler Toledo density meter type DE50 with an uncertainty of about 10 -5 g‚cm -3 . Prior to mea- surement, the instrument was calibrated with double- distilled water at 293.15 K, 303.15 K, and 313.15 K. The temperature of the measuring cell was maintained at 293.15 K, 303.15 K, and 313.15 K using a Julabo refriger- ated and heating circulator (model F12-MD with an uncertainty of 0.1 K). Viscosity Measurements. For the viscosity measure- ment, an Anton Paar type AMV n automatic microvisco- simeter equipped with an automatic timer ((0.01 s), was used. This instrument uses the rolling ball principle * Corresponding author. E-mail: suryadi@mail.wima.ac.id. Tel: 62 31 3891264. Fax: 62 31 3891267. Table 1. Comparison of the Experimental Density and Viscosity of Pure Compounds with Literature Values at 293.15 K, 303.15 K, and 313.15 K FL/g‚cm -3 ηL/mPa‚s compound T/K exptl lit exptl lit cis-3-hexenyl formate 293.15 0.90915 0.599 303.15 0.90660 0.527 313.15 0.90317 0.469 butyl acetate 293.15 0.88104 0.732 303.15 0.87130 0.87120 15 0.628 0.631 15 313.15 0.86184 0.546 trans-2-hexenyl acetate 293.15 0.89784 0.89800 16 0.901 303.15 0.89178 0.770 313.15 0.88435 0.666 cis-3-hexenyl acetate 293.15 0.90082 0.893 303.15 0.89314 0.763 313.15 0.88619 0.660 ethanol 293.15 0.78824 1.160 303.15 0.78073 0.78080 17 0.78068 18 0.968 0.995 17 0.987 18 313.15 0.77198 0.77213 18 0.810 0.814 18 1009 J. Chem. Eng. Data 2005, 50, 1009-1013 10.1021/je0500025 CCC: $30.25 © 2005 American Chemical Society Published on Web 04/16/2005