The density and viscosity correlation for several common fragrance and flavour esters

J. Chem. Eng. Data 2005, 50, 727-731 727 Density and Viscosity Correlation for Several Common Fragrance and Flavor Esters Hiannie Djojoputro and Suryadi Ismadji* Department of Chemical Engineering, Widya Mandala Surabaya Catholic University, Kalijudan 37, Surabaya 60114, Indonesia The density and viscosity of several fragrance and flavor esters were measured over a temperature range of (293.15 to 343.15) K. The esters studied were ethyl formate, cis-3-hexenyl formate, ethyl acetate, butyl acetate, isoamyl acetate, hexyl acetate, trans-2-hexenyl acetate, cis-3-hexenyl acetate, ethyl propionate, ethyl butyrate, butyl butyrate, isoamyl butyrate, hexyl butyrate, cis-3-hexenyl isobutyrate, ethyl isovalerate, ethyl 2-methylbutyrate, and ethyl hexanoate. The experimental data were correlated by temperature-dependence equations. Introduction In the flavor and fragrance industries, aliphatic and acrylic esters are important materials in manufacturing processes.1 Most of the esters used in the flavor and fragrance industries are acetates, and ethanol is the most common alcohol component. In addition to straight-chain saturated compounds, branched-chain compounds and unsaturated compound esters are also important. Several studies of the thermodynamic behavior and physical properties of several ester compounds in binary mixtures have been performed.1-4 However, detailed investigations of the physical properties of pure esters, especially their densities and viscosities over a wide range of temperature, are scarce in the literature. Therefore, this study was undertaken to obtain reliable density and viscosity data for a number of important flavor esters over a wide temperature range. The fragrance and flavor ester compounds chosen in this study with their physical characteristics are given in Table 1. Experimental Section Materials. High-purity and AR-grade samples of fragrance and flavor esters were purchased from SigmaAldrich 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 purities of these esters are given in Table 1. Density Measurements. Measurements of the densities of the pure components were carried out using a Mettler Toledo density meter type DE50 with an uncertainty of about 10-5 g‚cm-3. Prior to measurement, the instrument was calibrated with double-distilled water. The temperature of the measuring cell was maintained at various temperatures using a Julabo Thermostat model F12-MD with an uncertainty of 0.1 K. Viscosity Measurements. For viscosity measurements, an automatic microviscosimeter (Anton Paar type AMVn) equipped with an automatic timer ((0.01 s) was used. This instrument uses the rolling-ball principle according to DIN * To whom correspondence should be addressed. E-mail: suryadi@ mail.wima.ac.id. Tel: 62 31 3891264. Fax: 62 31 3891267. 53015 and ISO/DIS 12058, where a gold-covered steel ball rolls down inside an inclined, sample-filled glass capillary (diameter 0.16 cm). The uncertainty in time in the range of (0 to 250) s is less than 0.02 s with a resolution of (0.01 s. The temperature range of this viscosimeter is (283.15 to 343.15) K with an uncertainty of less than 0.05 K. The instrument was periodically calibrated with double-distilled water. The uncertainty in the viscosity measurement was estimated to be better than 0.004 mPa‚s. The measuring temperature was kept at the desired temperature by placing the sample-filled glass capillary in a block controlled with a Julabo refrigerating and heating circulator. All measurements described above were performed at least three times, and the results were averaged to give the final values. Experimental Results The experimental results of the density and viscosity measurements of several fragrance and flavor ester compounds are given in Table 2. The density and viscosity of ethyl formate were measured only at 323.15 K, whereas for trans-2-hexenyl acetate and cis-3-hexenyl acetate the density and viscosity were measured only at 333.15 K because of the low boiling points of these esters. From this Table, it can be seen that the experimental values of the density and viscosity are generally in agreement with those from the literature.1,4-10 However, for several viscosity data points, the deviation between experimental and literature data is as high as 0.04 mPa‚s. This deviation is likely due to impurities in the flavor esters that we used. The densities of pure esters were correlated using a temperature-dependence equation that has the following form: F(T)/g‚cm-3 ) a + b(T/K) + c(T/K)2 (1) Here, F(T) is the density of the ester at absolute temperature and a, b, and c are fitted parameters. The fitted density parameters of each ester and standard deviation (σ) between experimental and calculated data are summarized in Table 3. Figure 1 depicts the experimental density data and predicted value versus temperature for several flavor esters. From Table 3 and Figure 1, it can be seen that eq 1 can predict the experimental data very well. 10.1021/je050001c CCC: $30.25 © 2005 American Chemical Society Published on Web 02/19/2005 728 Journal of Chemical and Engineering Data, Vol. 50, No. 2, 2005 Table 1. Physical Characteristics of the Esters Used in This Study5 name of ester molecular molecular formula weight/g‚mol-1 characteristic purity/% clear liquid with a slightly pungent, fruity, ethereal odor 98.2 fruit flavors green-fruity odor, sweet 97.4 perfume and flavor to impart fruity-green notes fruity-smelling liquid with a brandy note 99.6 fruit and brandy flavors 116.16 liquid with a strong fruity odor 99.7 constituent of apple aroma 130.19 strongly fruity-smelling liquid 98.9 banana flavors C8H16O2 144.21 liquid with a sweet-fruity, pearlike odor 99.0 fruit aroma composition C8H14O2 142.20 fresh-fruity, slightly greensmelling liquid 98.9 fruit flavors ethyl formate C3H6O2 74.08 cis-3-hexenyl formate C7H12O2 128.17 ethyl acetate C4H8O2 88.11 butyl acetate C6H12O2 isoamyl acetate C7H14O2 hexyl acetate trans-2-hexenyl acetate used cis-3-hexenyl acetate C8H14O2 142.20 fruit aromas and green tea 99.5 fruit flavors ethyl propionate C5H10O2 102.13 liquid with fruity odor reminiscent of rum 99.4 creating both fruity and rum notes ethyl butyrate C6H12O2 116.16 clear liquid with a fruity odor reminiscent of pineapples 99.6 perfume and flavor compositions butyl butyrate C8H16O2 144.21 clear liquid with a sweet-fruity odor 99.3 fruit flavor composition isoamyl butyrate C9H18O2 158.23 clear liquid with a very strong fruity odor 98.5 fruit flavors hexyl butyrate C10H20O2 172.27 liquid with a very strong fruity odor 98.4 fruit flavor composition cis-3-hexenyl isobutyrate C10H18O2 170.25 fruity-green odor 96.2 in perfume to create freshness in blossom compositions ethyl isovalerate C7H14O2 130.19 colorless liquid with a fruity odor reminiscent of blueberries 98.8 fruity aroma composition ethyl 2-methylbutyrate C7H14O2 130.19 liquid with a green-fruity odor reminiscent of apples 99.2 fruit flavor compositions ethyl hexanoate C8H16O2 144.21 colorless liquid with a strong fruity odor reminiscent of pineapples 98.7 flowery-fruity notes in perfume compositions and fruit flavors Figure 1. Experimental density data and correlated values for several flavor esters: b, ethyl formate; 9, cis-3-hexenyl formate; 2, trans-2-hexenyl acetate; [, cis-3-hexenyl isobutyrate. The viscosity of fragrance and flavor esters is a function of temperature and can be represented by the following equation log(η/mPa‚s) ) A + B + C(T/K) + D(T/K)2 T/K (2) where A, B, C, and D are fitted parameters and η is the viscosity of pure esters in mPa‚s. The fitted viscosity parameters of each ester and standard deviation (σ) between experimental and calculated data are summarized in Table 4. Figure 2 shows the experimental viscosity data Figure 2. Experimental viscosity data and predicted values for several flavor esters: b, ethyl acetate; 9, hexyl butyrate; 2, ethyl 2-methylbutyrate; [, isoamyl acetate. and predicted value versus temperature for several flavor esters. Table 4 and Figure 2 reveal that eq 2 can also represent the experimental viscosity data very well. Conclusions New experimental density and viscosity data for several important flavor ester compounds over a wide range of temperature were obtained. The results were then correlated using temperature-dependence equations. It was found that the models used in this study represent the experimental data very well. Journal of Chemical and Engineering Data, Vol. 50, No. 2, 2005 729 Table 2. Densities and Viscosity of Fragrance and Flavor Esters at Temperatures from (293.15 to 343.15) K FL/g‚cm-3 compounds ethyl formate T/K 293.15 exptl 0.91782 FL/g‚cm-3 η/mPa‚s lit 0.916805 exptl lit η/mPa‚s T/K exptl lit exptl 318.15 323.15 328.15 333.15 343.15 0.88741 0.88214 0.883906 0.314 0.300 323.15 328.15 333.15 338.15 343.15 0.89899 0.89672 0.89416 0.89154 0.88873 0.421 0.400 0.380 0.363 0.346 0.4244 0.4004 0.3854 323.15 328.15 333.15 338.15 343.15 0.87039 0.86713 0.86472 0.86141 0.85836 0.330 0.315 0.301 0.288 0.275 0.6318 323.15 328.15 333.15 338.15 343.15 0.85461 0.85078 0.84792 0.84439 0.84177 0.481 0.453 0.428 0.405 0.384 323.15 328.15 333.15 338.15 343.15 0.86431 0.86014 0.85798 0.85405 0.85107 0.601 0.567 0.536 0.507 0.481 0.402 0.920806 298.15 303.15 308.15 313.15 0.91206 0.90768 0.89954 0.89150 cis-3-hexenyl formate 293.15 298.15 303.15 308.15 313.15 318.15 0.90915 0.90813 0.90660 0.90495 0.90317 0.90119 ethyl acetate 293.15 298.15 303.15 308.15 313.15 318.15 0.90048 0.89481 0.88714 0.88221 0.87892 0.87451 293.15 298.15 303.15 308.15 313.15 318.15 0.88104 0.87645 0.87130 0.86625 0.86184 0.85732 isoamyl acetate 293.15 298.15 303.15 308.15 313.15 318.15 0.87824 0.87601 0.87594 0.87310 0.87015 0.86732 0.86800-0.878005 0.888 0.827 0.773 0.724 0.678 0.638 hexyl acetate 293.15 0.87290 1.118 1.0781 323.15 0.84421 0.733 298.15 303.15 0.86730 0.86260 0.873101 0.872609 0.868005 0.863201 0.863609 1.036 0.962 0.9821 328.15 333.15 0.83964 0.83515 0.689 0.649 308.15 313.15 0.85833 0.85490 338.15 343.15 0.83140 0.82630 0.612 0.579 0.901 0.831 0.770 0.715 0.666 0.622 323.15 328.15 333.15 338.15 343.15 0.87614 0.87281 0.86749 0.582 0.547 0.514 0.893 0.823 0.763 0.708 0.660 0.616 323.15 328.15 333.15 338.15 343.15 0.87789 0.87521 0.87143 0.576 0.542 0.509 0.523 0.492 0.464 0.441 0.418 0.398 323.15 328.15 333.15 338.15 343.15 0.86433 0.86089 0.85814 0.85681 0.85348 0.378 0.360 0.344 0.329 0.315 butyl acetate 0.907606 0.893606 0.908005 0.900305 0.894507 0.882397 0.876307 0.871208 0.866207 0.853501 0.854609 0.381 0.362 0.345 0.329 0.599 0.561 0.527 0.496 0.469 0.443 0.443 0.421 0.399 0.381 0.363 0.346 0.732 0.677 0.628 0.585 0.546 0.512 0.895 0.836 318.15 0.84884 trans-2-hexenyl acetate 293.15 298.15 303.15 308.15 313.15 318.15 0.89784 0.89432 0.89178 0.88846 0.88435 0.88019 0.782 cis-3-hexenyl acetate 293.15 298.15 303.15 308.15 313.15 318.15 0.90082 0.89714 0.89314 0.89028 0.88619 0.88143 ethyl propionate 293.15 298.15 303.15 308.15 313.15 318.15 0.89162 0.88410 0.87931 0.87412 0.87061 0.86734 0.891705 ethyl butyrate 293.15 298.15 303.15 308.15 313.15 318.15 0.87691 0.87442 0.87013 0.86621 0.86431 0.86132 0.878505 0.8734710 0.662 0.620 0.583 0.549 0.519 0.491 323.15 328.15 333.15 338.15 343.15 0.85843 0.85444 0.85389 0.85132 0.85004 0.465 0.442 0.420 0.400 0.382 butyl butyrate 293.15 298.15 303.15 308.15 313.15 318.15 0.87245 0.86914 0.86610 0.86219 0.85894 0.85431 0.870905 0.948 0.876 0.812 0.755 0.705 0.659 323.15 328.15 333.15 338.15 343.15 0.85147 0.84801 0.84622 0.84403 0.84147 0.618 0.581 0.548 0.517 0.486 isoamyl butyrate 293.15 298.15 303.15 308.15 313.15 318.15 0.86613 0.86204 0.85914 0.85708 0.85342 0.85011 0.865105 1.044 0.967 0.897 0.836 0.781 0.731 323.15 328.15 333.15 338.15 343.15 0.84578 0.84231 0.84073 0.83545 0.83276 0.686 0.646 0.609 0.575 0.545 0.898005 0.878878 0.4948 lit 730 Journal of Chemical and Engineering Data, Vol. 50, No. 2, 2005 Table 2 (Continued) FL/g‚cm-3 compounds T/K lit exptl 0.865205 hexyl butyrate 293.15 298.15 303.15 308.15 313.15 318.15 0.86073 0.85100 0.84652 0.84151 0.83746 0.83465 cis-3-hexenyl isobutyrate 293.15 298.15 303.15 308.15 313.15 318.15 0.88508 0.87812 0.87361 0.87034 0.86522 0.86149 ethyl isovalerate 293.15 298.15 303.15 308.15 313.15 318.15 0.86623 0.86401 0.86012 0.85598 0.85179 0.84739 ethyl 2-methylbutyrate 293.15 298.15 303.15 308.15 313.15 318.15 0.86973 0.86500 0.86148 0.85788 0.85341 0.84932 ethyl hexanoate 293.15 298.15 303.15 308.15 313.15 318.15 0.87901 0.87253 0.86931 0.86674 0.86328 0.86019 FL/g‚cm-3 η/mPa‚s exptl 0.865605 0.868905 0.871005 lit η/mPa‚s T/K exptl lit exptl 1.351 1.234 1.131 1.014 0.961 0.889 323.15 328.15 333.15 338.15 343.15 0.83078 0.82819 0.82677 0.82381 0.82076 0.825 0.768 0.716 0.669 0.627 1.024 0.941 0.868 0.804 0.741 0.690 323.15 328.15 333.15 338.15 343.15 0.85738 0.85244 0.84844 0.84531 0.84009 0.650 0.606 0.560 0.535 0.503 0.805 0.752 0.703 0.659 0.620 0.581 323.15 328.15 333.15 338.15 343.15 0.84624 0.84235 0.84007 0.83631 0.83362 0.544 0.516 0.485 0.457 0.431 0.831 0.774 0.723 0.677 0.635 0.597 323.15 328.15 333.15 338.15 343.15 0.84674 0.84159 0.83841 0.83548 0.83146 0.563 0.532 0.503 0.476 0.452 0.816 0.757 0.704 0.656 0.614 0.576 323.15 328.15 333.15 338.15 343.15 0.85642 0.85193 0.84788 0.84532 0.84146 0.541 0.509 0.482 0.456 0.429 lit Table 3. Parameters for the Density Correlation for the Fragrance and Flavor Esters compounds a b c σ ethyl formate cis-3-hexenyl formate ethyl acetate butyl acetate isoamyl acetate hexyl acetate trans-2-hexenyl acetate cis-3-hexenyl acetate ethyl propionate ethyl butyrate butyl butyrate isoamyl butyrate hexyl butyrate cis-3-hexenyl isobutyrate ethyl isovalerate ethyl 2-methylbutyrate ethyl hexanoate 1.46554 0.67480 1.99860 1.69608 0.59007 1.20940 0.74015 1.19615 1.97642 1.47568 1.42365 0.95837 2.09934 1.33005 1.31271 1.23053 1.11638 -2.44133 × 10-3 1.83502 × 10-3 -6.24971 × 10-3 -4.48155 × 10-3 2.30538 × 10-3 -1.34331 × 10-3 1.66995 × 10-3 -1.23970 × 10-3 -6.25409 × 10-3 -3.31059 × 10-3 -2.93727 × 10-3 -1.78027 × 10-5 -7.22490 × 10-3 -2.08366 × 10-3 -2.24912 × 10-3 -1.63423 × 10-3 -8.93011 × 10-4 1.96192 × 10-6 -3.53118 × 10-6 8.53568 × 10-6 5.80616 × 10-6 -4.50699 × 10-6 6.6227 × 10-7 -3.86207 × 10-6 7.94135 × 10-7 8.69699 × 10-6 4.33167 × 10-6 3.61375 × 10-6 -1.01675 × 10-6 1.02082 × 10-5 1.91639 × 10-6 2.48654 × 10-6 1.37424 × 10-6 2.68015 × 10-7 0.0041 0.0006 0.0016 0.0006 0.0026 0.0011 0.0011 0.0016 0.0021 0.0026 0.0021 0.0026 0.0021 0.0016 0.0026 0.0011 0.0016 Table 4. Parameters for Viscosity Correlation for the Fragrance and Flavor Esters compounds ethyl formate cis-3-hexenyl formate ethyl acetate butyl acetate isoamyl acetate hexyl acetate trans-2-hexenyl acetate cis-3-hexenyl acetate ethyl propionate ethyl butyrate butyl butyrate isoamyl butyrate hexyl butyrate cis-3-hexenyl isobutyrate ethyl isovalerate ethyl 2-methylbutyrate ethyl hexanoate a -5.06064 -6.01904 -4.74308 -5.49829 -5.02068 -4.40456 -5.31784 -5.33417 -5.14522 -5.17455 -7.18299 -5.23957 -5.56517 -5.36123 -4.72611 -5.12216 -6.42963 b 737.37681 954.74783 659.9798 103 1000.90027 865.50152 856.32033 976.68866 976.77772 806.15186 852.90821 1161.06978 959.94502 1119.93544 1021.97306 759.09741 884.82001 1054.49049 c 0.01075 0.01202 0.01145 0.0086087 9.9597 × 10-3 7.3099 × 10-3 9.0022 × 10-3 9.0874 × 10-3 0.01028 0.01003 0.01531 9.2246 × 10-3 8.0075 × 10-3 8.5427 × 10-3 0.01110 9.8046 × 10-3 0.01315 d σ 10-5 -1.16726 × -1.14524 × 10-5 -1.41899 × 10-5 -6.69263 × 10-6 -1.05078 × 10-5 -7.10792 × 10-6 -8.12428 × 10-6 -8.27495 × 10-6 -1.04632 × 10-5 -9.94419 × 10-6 -1.49862 × 10-5 -8.38321 × 10-6 -5.49352 × 10-6 -7.19934 × 10-6 -1.41134 × 10-5 -9.89965 × 10-6 -1.29215 × 10-5 0.0011 0.0006 0.0006 0.0011 0.0006 0.0006 0.0016 0.0006 0.0011 0.0006 0.0006 0.0011 0.0011 0.0011 0.0006 0.0006 0.0011 Journal of Chemical and Engineering Data, Vol. 50, No. 2, 2005 731 Literature Cited (1) Indraswati, N.; Mudjijati; Wicaksana, F.; Hindarso, H.; Ismadji, S. 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Densities and Viscosities of the Ternary Mixtures Water + Butyl Acetate + Methanol and Water + Ethyl Propionate + Methanol at 303.15 K. J. Chem. Eng. Data 2000, 45, 926-931. (9) Riddick, J. A.; Bunger, W. B.; Sakano, T. K. Organic Solvents: Physical Properties and Methods of Purification, 4th ed.; John Wiley & Sons: New York, 1986. (10) Resa, J. M.; Gonzalez, C.; de Landaluce, S. O.; Lanz, J. Density, Refractive Index, and Speed of Sound at 298.15 K, and Vapor Liquid Equilibria at 101.3 kPa for Binary Mixtures of Methanol + Ethyl Butyrate and Vinyl Acetate + Ethyl Butyrate. J. Chem. Eng. Data 2002, 47, 1123-1127. Received for review January 1, 2005. Accepted January 20, 2005. JE050001C