QSPR modeling of internal combustion for methylic and ethylic biodiesel

J. Morón-Villarreyes1, E. Miyasaki 1, Â. Carlos1, P. de Oliveira 1, P. de Abreu 1, R. Clementin1 and M. D´Oca1

1Universidade Federal do Rio Grande, Brazil

Keywords: QSPR, biodiesel from microalgae, molecular modeling, diesel engines
property: viscosity
material: methyl and ethyl esters

In this work a method for predicting the performance of fuels in by-compression ignition engines is presented. Using QSPR techniques, five correlations were obtained for the indicative parameters A, B, C, D, E which evaluate the fluid dynamics of a liquid as distribution of droplet diameter, flow, uniformity and disintegration time of jets of methyl and ethyl biodiesel. Flores-Luque et al.2 based on the model of Schweitzer1 define the parameters as A=μ/ρ , B=σ/μ, C=σ/ρ , D=σ2/μ ρ , E=μ2/ρ σ . In those dimensional groups ρ ,μ ,σ are the density, dynamic viscosity and surface tension. At 313K the indicative parameters should be inside these ranges: (2.64-4.39) (8.25-10.8) (28.7-32.5), (2:30 to 3:43) and (0.05-0.65) respectively2. Besides, to evaluate the performance of biodiesel in by-compression ignition engines they also allow determine the proper proportion diesel/biodiesel3. Correlations for μ , ρ and σ were obtained by Group Contribution and fitted by regression analysis in simple equations for each indicative parameters:


where the molecular descriptors are oleochemical characteristics as saponification (SV) and iodine (IV) values of the oil used in the synthesis of biodiesel. As an example, for methylic biodiesel: A[c1=-4.16, c2=1733.62, c3=-1.06]; B[c1=26.34, c2=-3927.91, c3=2.71]; C[c1=24.46, c2=1435.98, c3=0.74]; D[c1=7.82, c2=-1142.11, c3=0.94]; E[c1=-1.23, c2=369.93, c3=-0.25]. Also another set of constants for ethylic biodiesel was found. The equations satisfactorily determined the diesel/biodiesel proportion with adequate performance for the oil of 280 algae from AlgaE-Energy database4.

  1. P.H. Schweitzer, J. Appl Phys, 8:513–21 (1937).

  2. V. Flores-Luque, H. Galán Soldevilla, C.G. Herrera, Oléagineaux, 42(12):475–481 (1987)

  3. J.A. Morón-Villarreyes, C. Soldi, A. M. Amorim, M.G. Pizzolatti, A.P. Mendonca, M.G.M. D’Oca, Fuel, 86, 1977–1982 (2007)

  4. E.K. Miyasaki, V.F. Granjão, R.M. Clementin, M.G.M. D’oca, J.A. Morón-Villarreyes, J.A. Anais do VIº Congresso Brasileiro de Plantas Oleaginosas, Óleos, Gorduras e Biodiesel, (2009).

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