Measurement and correlation of density and viscosity of n-hexadecane with three fatty acid ethyl esters

https://doi.org/10.1016/j.jct.2016.01.021Get rights and content

Highlights

  • Density and viscosity of mixtures for n-hexadecane with three fatty acid ethyl esters were reported.

  • Excess molar volumes and viscosity deviations were obtained.

  • The viscosities of the binary mixtures were correlated using a rough hard-sphere model.

Abstract

This work reports the density and viscosity of binary mixtures for n-hexadecane with three fatty acid ethyl esters (ethyl caprylate, ethyl caprate, and ethyl laurate) in the overall composition range at temperatures from 298.15 to 323.15 K and at atmospheric pressure (0.1 MPa). Excess molar volumes and viscosity deviations have been obtained. In addition, the viscosities of the binary mixtures were correlated using a rough hard-sphere model. The average absolute relative deviations between the experimental data and the calculated values were 0.26% for n-hexadecane/ethyl caprylate, 0.30% for n-hexadecane/ethyl caprate, and 0.24% for n-hexadecane/ethyl laurate with optimized adjustable parameters. It indicates that the rough hard-sphere model is able to reproduce the viscosity behavior of the studied binary mixtures very well.

Introduction

Biodiesels consist of mixtures of alkyl esters of fatty acid (typically methyl or ethyl) obtained by a transesterification reaction where a vegetable oil or an animal fat is combined with a short chain alcohol such as methanol or ethanol [1]. Biodiesel has a high cetane number, wherefrom reduced solid particle and hydrocarbons emissions. It is, therefore, considered as a renewable and environmental friendly alternative diesel fuel for diesel engine. In the last few years, researchers have made effort to establish novel approaches to improve the production or purification of biodiesels [2], [3], [4]. In addition, to study the thermophysical properties of fatty esters or biodiesels have attracted more and more attention [5], [6], [7], [8].

Due to the complete miscibility of biodiesel with diesel oil, the blending of both fuels in any proportion may improve fuel qualities and engine performance [9]. The knowledge of the thermodynamics and transport properties of the mixtures of biodiesel + diesel oil is essential to optimize the diesel engine. Density and viscosity are the most important properties of a fuel, influencing especially the injection system, atomization quality and combustion quality. Several investigations on the density and viscosity of biodiesel + diesel oil mixtures have been reported in the literature [10], [11], [12], [13]. As biodiesels and diesel oils are all multi-component mixtures, changes in compounds profile affect their densities and viscosities. The knowledge of the properties of the pure compounds or its mixtures enables the prediction of the properties of biodiesel + diesel oil mixtures. To the best of our knowledge, the density and viscosity of n-hexadecane (a reference molecule for modeling diesel oil thermodynamics properties) with pure fatty acid ethyl esters (for example, ethyl caprylate, ethyl caprate, or ethyl laurate) have not been reported in the literature. In this work, the density and viscosity of binary mixtures of n-hexadecane with ethyl caprylate, ethyl caprate, and ethyl laurate at temperatures from 298.15 to 323.15 K over the entire composition range were reported, and the excess molar volumes and viscosity deviations were obtained.

Section snippets

Samples

n-Hexadecane (CH3(CH2)14CH3), ethyl caprylate (CH3(CH2)6COOCH2CH3), ethyl caprate (CH3(CH2)8COOCH2CH3), and ethyl laurate (CH3(CH2)10COOCH2CH3) were supplied by Aladdin Chemistry and the mass purity was better than 99%. All samples were used without further purification. Table 1 shows the sample descriptions used in the present work. The densities and viscosities of the pure components were measured and compared to the literatures [14], [15], [16], [17], [18], [19], [20], [21], [22], [23], [24]

Results and discussion

The experimental density and viscosity results of the binary mixtures n-hexadecane with ethyl caprylate, ethyl caprate, and ethyl laurate over the temperature range from 298.15 to 323.15 K at atmospheric pressure are listed in TABLE 3, TABLE 4, respectively.

The excess molar volume VE can be obtained from experimental density data according to the following equation:VE=i=12xiMi1ρ-1ρiwhere xi, Mi, and ρi are the mole fraction, molar mass, and density of the pure component i, respectively. ρ is

Viscosity correlation

In this work, the rough hard-sphere theory, proposed by Chandler [31], was used to correlate the viscosity of the studied binary mixtures. The rough hard sphere expressions for the reduced viscosity (η) as functions of the reduced molar volume Vr=V/V0 are as follows [32], [33], [34]:log(η/Rη)=1.0945-9.2632Vr-1+71.0385Vr-2-301.9012Vr-3+797.69Vr-4-1221.977Vr-5+987.5574Vr-6-319.4636Vr-7

The reduced viscosity is defined asη=6.035×1081MRT1/2ηV2/3where M is the molar mass, R is the gas constant, T

Conclusion

New experimental data for densities and viscosities of binary mixtures of n-hexadecane with ethyl caprylate, ethyl caprate, and ethyl laurate were reported at temperatures ranging from 298.15 to 323.15 K at atmospheric pressure. Results show that, for the studied systems, the excess molar volumes are positive for all the compositions at different temperatures. However, the deviations in viscosity are negative and show larger negative values with decreased temperature in every case. In addition,

Acknowledgment

The authors are grateful to acknowledge financial support for the work by National Natural Science Foundation of China (Grant No. 51476129).

References (37)

  • G. Knothe

    Prog. Energy Combust. Sci.

    (2010)
  • A. Demirbas

    Energy Convers. Manage.

    (2009)
  • X. Liu et al.

    Fuel

    (2015)
  • S.V.D. Freitas et al.

    Fuel

    (2013)
  • M. Dzida et al.

    Fuel

    (2013)
  • S. Outcalt et al.

    J. Chem. Thermodyn.

    (2010)
  • J.N. Wu et al.

    Fluid Phase Equilib.

    (1998)
  • X. Wang et al.

    J. Chem. Thermodyn.

    (2013)
  • F.A. Vanessa et al.

    Fuel Process. Technol.

    (2015)
  • F. Obie et al.

    Appl. Energy

    (2015)
  • M.J. Pratas et al.

    J. Chem. Eng. Data

    (2011)
  • H. Mattieu et al.

    J. Chem. Eng. Data

    (2015)
  • G. Sibel et al.

    Fuel

    (2015)
  • G. Knothe et al.

    Energy Fuels

    (2006)
  • S. Kumar et al.

    J. Chem. Eng. Data

    (2011)
  • S. Baroutian et al.

    J. Chem. Eng. Data

    (2010)
  • R.C. Parente et al.

    J. Chem. Eng. Data

    (2011)
  • C.A. Nogueira et al.

    J. Chem. Eng. Data

    (2012)
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