Densities and excess molar volumes of mixtures containing diesel,biodiesel and alkanols at temperatures from 288.15 to 313.15 K

Sunita Malik,Poonam Jangra Darolia,S.K.Garg,V.K.Sharma,*

1 Department of Chemistry,Maharshi Dayanand University,Rohtak,Haryana,India

2 J.C.Bose University of Science and Technology,YMCA,Faridabad,Haryana,India

Keywords: Jatropha curcas biodiesel Diesel Alcohols Blends Density Excess molar volumes

ABSTRACT The present work is focusing on the synthesization and physico-chemical properties of Jatropha curcas biodiesel with diesel and alcohols.The densities of binary diesel(2)+1-alkanols(C3 or C4)(3)and ternary Jatropha curcas biodiesel (1) + diesel (2) + 1-alkanols (C3 or C4) (3) blends have been reported over full range of composition at temperatures within range 288.15 to 313.15 K.Also densities of Jatropha curcas biodiesel (1) + diesel or 1-alkanols (C3 or C4) (2) blends have been measured at 313.15 K.Excess molar volumes, VE, of binary and ternary blends were calculated from the measured data and the derived properties were correlated to composition using Redlich–Kister equation.A reasonable agreement was found between the measured and estimated values.Further,densities and excess molar volumes data were reasoned to discuss molecular interactions taking into consideration effect of composition and temperature.

1.Introduction

Now a day’s energy security is one of the global leading issue.Rising global energy environment and shrinking fossil fuel have attracted the attention of the researchers to look for alternate resource of energy possessing low global warming and pollution[1–3].The annual global emission of CO2in the last decade has increased the temperature of the world by 2 °C [4].The reduction of the green house emission effect from fuels is the main purpose of Kyoto protocol and of Paris resolution [5].Also depletion of world petroleum reservoirs has forced the scientists to look for substitute energy sources so that fossil fuel be preserved for a longer period.Biodiesel is an auspicious diesel fuel for conservative fossil diesel,as its properties are similar to fossil fuel.The biodiesel has been used widely as alternative fuel in the last decade and estimated biodiesel production is estimated to be~34 billion L by 2020[6,7].The replacement of a diesel with biodiesel may affect the spray possessions and combustion process of a fuel as viscosity and density of biodiesel is greater than those from diesel[8].Such problems in industries may overcome by making blends of biodiesel with diesel or other liquids like alcohols having low viscosity.The blends of biodiesel,diesel and alkanols thus may be of great importance in petrochemical and automotive industries [9].Density data of liquid mixtures are important for various engineering processes and unit operations [10,11].Fuel efficacy is also governed by its density and thus considered to be one of the significant factor for the operation of diesel operation engine [12].The high density fuel can provide more mass to the fuel injection system of an engine and thus enhance efficiency of its operation[13].Thermodynamic properties of mixtures(blends)comprised of biodiesel or diesel or any additive material therefore,has been an area of researchers for the last decade [14–17].

Fig.1.The GC Graph of biodiesel.

The common feedstock’s of biodiesel production in the universe are additive oils,indigenous non-edible plants,animal plants,algae and lignocellulosic raw materialetc[18,19].Jatropha curcasis nonedible plant species and is considered to be the source of most alternative fuel [20].The oil extracted fromJatropha curcasis trans-esterified to methyl esters yielding biodiesel [21].Also biodiesel obtained fromJatropha curcasmeet the current biodiesel standards proposed by various agencies.Fuel industries require a large number of materials with low viscosities to be added to biodiesel or diesel to enhance fuel efficacy.The selected liquids for the present studies are 1-propanol and 1-butanol.1-butanol possesses ability to reduce carbon monoxide and also to work in the internal combustion of engine without modification [22].These alkanols also act as better blender (than ethanol) with biodiesel or diesel due to their properties like low density,flash point,ignition temperature,latent heat of vaporization[23].A survey of literature shows that densities of ternary mixture(blends)ofJatropha curcasbiodiesel(1)+diesel(2)+1-alkanols(C3or C4)(3)(ternary blends)have not been studied yet.These concerns incited us to measure the densities of aforesaid ternary mixtures (ternary blends) and their sub-binaries diesel + 1-alkanols (C3or C4) (binary blends) as a function of mole fraction atT=(288.15–313.15) K with interval of 5 K and atmospheric pressure.Densities,excess molar volumes data of binaryJatropha curcasbiodiesel(1)+diesel(2)or 1-alkanols(C3or C4) (3) blends reported and interpreted in our earlier publications [24–26]at temperatures from 288.15-308.15 K and also have been reported in the present study at 313.15 K.suchVEdata at 313.15 K were required to estimate binary coefficients for the aforesaid blends and the same were employed to calculate ternary coefficients by fittingVEanddata to Redlich-Kister equation.The investigated study is also a part of the research project sanctioned to us by CSIR (New Delhi,India).

2.Experimental

2.1.Materials

2.1.1.Biodiesel synthesization and characterization

Jatropha curcas(J.curcas)seeds were used to extract oil.J.curcasbiodiesel was synthesizedviatrans esterification of the extracted oil in a manner as described elsewhere [24].

The biodiesel composition was estimated using gas chromatography(GC)as discussed elsewhere[24].The GC Graph of biodiesel is shown in Fig.1.Biodiesel peaks was identified related to retention time between sample and standard biodiesel.The estimated composition of biodiesel are presented in Table S1.The results obtained are comparable with published data [27].Its average molecular weight was estimated 0.870 kg·mol-1.

Table 1Description of liquids in the Present Work

Table 2Measured ρ of liquids used in present work and also their comparison with literature values at the corresponding temperatures and p=0.1 MPa

Table 3Theρ123 and data for ternary mixtures at T=(288.15–313.15) K and p=0.1 MPa

Table 3Theρ123 and data for ternary mixtures at T=(288.15–313.15) K and p=0.1 MPa

Table 3 (continued)

Table 3 (continued)

2.1.2.Diesel fuel No 2

The automotive fuel No.2 containing components [24]having average molecular weight 0.233 kg·mol-1[28].1-propanol (mass fractionw: 0.995) and 1-butanol of (mass fractionw: 0.995) purchased from M/S Sigma Aldrich and purified by standard methods[29].The description of the chemicals used in current study has been given in Table 1.

2.2.Measurements

The densities,ρ of the present binary/ternary blends were measured from 288.15 K to 313.15 K with step of 5 K interval by using Anton Paar,DSA-5000 digital vibrating tube densimeter in a manner as described previously [30,31].The densities ofJ.curcasbiodiesel,diesel,1-propanol and 1-butanol tabulated in Table 2 are compared with their literature data.Such values were found to be in agreement with literature data [32–40].The studied blends were prepared by mass using electric balance (Mettler AX-205 Delta Range)with a precision of 10-8kg.The standard uncertainty of density value were estimated as discussed elsewhere [41–43]The standard uncertainties of ρ and mole fraction were found to be 0.05 kg·m-3and 1×10-4respectively.

3.Results and Discussion

The ρ,ρ123for diesel(2)+1-alkanols(C3or C4)(3)andJ.curcasbiodiesel (1) + diesel (2) + 1-alkanols (C3or C4) (3) blends respectively at 288.15,293.15,298.15,303.15,308.15 and 313.15 K gathered in Tables S2 and 3 are graphically shown in Figs.2–5 respectively.

Standard uncertainties,u,areu(T)=0.01 K;u(x1)=1×10-4;u(ρ)=0.05 kg·m-3.

Also ρ ofJ.curcasbiodiesel (1) + diesel (2) or 1-alkanols (C3or C4) (3) blends at 313.15 K have been listed in Table S2.The ρ and ρ123were utilized for the determination ofVE,for binary,ternary blends using relations:

Table 4Adjustable parameters, Vn (n=0–2) of Eq.(3) together with standard deviations,σ (VE) of VE at T=(288.15–313.15) K

Table 5Ternary adjustable parameters, (n=0–2) of Eq. (4) together with the standard deviations,σ（） at T=(293.15–308.15) K.

Table 5Ternary adjustable parameters, (n=0–2) of Eq. (4) together with the standard deviations,σ（） at T=(293.15–308.15) K.

wherexi,Mi,ρi(i=1–3) denotes the compositions,molar weight and densities of parent components of blends,ρ ,ρ123depicts the densities of binary and ternary blends respectively.

Fig.2.ρ values for diesel (2) +1-propanol (3) at ( )288.15 K; () 293.15 K; ()298.15 K; () 303.15 K; () 308.15 K; () 313.15 K.

Fig.3.ρ values for diesel (2) + 1-butanol (3) at ( ) 288.15 K; () 293.15 K; ()298.15 K; () 303.15 K; () 308.15 K; () 313.15 K.

wherem,ndepicts number of data points and adjustable parameters of Eqs.(5) and (6) respectively are listed in Table 4 and 5 respectively.VEanddata calculated by Eqs.(5) and(6) are also plotted in Figs.6–9 respectively.

The densities,ρ data of binary diesel (2) + 1-propanol or 1-butanol (3) blend at the investigated temperatures (Table S2) are found to be increasing with increase in concentration of diesel and decreasing with rise in temperature or vice-versa.The ρ data of these blends suggest that while addition of 1-propanol reduce the density of the diesel.However,magnitude of density for diesel + 1-butanol is governed by the relative proportion of the constituents.It has been observed that density values of diesel(1)+propanol(2)mixtures at 288.15 K exhibit different trend than at 313.15 K(Fig.2).It may be due to the reason that with increase of temperature rupture of intermolecular hydrogen bonding in 1-propanol molecule takes place at higher rate.The ρ of diesel(2) + 1-propanol (3) blends are lesser than those for diesel(2)+1-butanol(3)blends.It may be due to the reason that addition of diesel(comprised of non-polarized alkanes,cycloalkanes,olefins and aromatic hydrocarbons) may rupture self-association of 1-propanol and thus results in increase in volume.1-butanol possesses large number of carbon atoms chain and thus has least self-association in comparison to 1-propanol.The higher density of diesel + 1-butanol in comparison to diesel + 1-propanol indicated that diesel + 1-butanol blend may act as a better fuel than diesel + 1-propanol in a fuel injection system of a diesel operated engines.Further,decreasing values of density with increasing temperature suggest that there is a rupture of self-association of 1-propanol or 1-butanol and also increase in mobility of molecules with increase in temperature.In view of these,binary blends would be occupying more space in comparison to their parent molecules.

Fig.4.ρ123 for Jatropha curcas biodiesel(1)+diesel(2)+1-propanol(3)at 298.15 K.

Fig.5.ρ123 for Jatropha curcas biodiesel(1)+diesel(2)+1-butanol(3)at 298.15 K.

Fig.6. VE for diesel (2) + 1-propanol (3) ( ) at 288.15 K; () at 293.15 K; () at 298.15 K; () 303.15 K; () 308.15 K; () 313.15 K.

Fig.7. VE for diesel (2) + 1-butanol (3) ( ) at 288.15 K; () 293.15 K; ()298.15 K; () 303.15 K; () 308.15 K; () 313.15 K.

The densities of ternaryJ.curcasbiodiesel (1) + diesel (2) + 1-alkanols(C3or C4)(3)blends are lower than those for binaryJ.curcasbiodiesel(1)+diesel(2)blend[24].The density data for aforesaid ternary blends indicated that these may act as better blends than those of binary blends comprised of biodiesel and diesel.Further,densities ofJ.curcasbiodiesel(1)+diesel(2)+1-propanol(3)blends are lesser than those fromJ.curcasbiodiesel (1) + diesel(2) + 1-butanol (3) blends suggesting that addition of diesel toJ.curcasbiodiesel + alkanols mixtures may results in the rupture of hydrogen bonding biodiesel and alkanols mixture[25,26].The densities of studied ternary blends vary inversely with temperature.

Fig.8. for Jatropha curcas biodiesel(1)+diesel(2)+1-propanol(3)at 298.15 K.

Fig.9. for Jatropha curcas biodiesel(1)+diesel(2)+1-butanol(3)at 298.15 K.

WhileVEof diesel (2) + 1-propanol(3) blends are positive over full composition range; sign and magnitude for diesel(2) + 2-butanol (3) are governed by relative proportion of diesel or 1-butanol.TheVEdata for the binary blends nearly at equi-mole fraction vary in the trend: 1-propanol > 1-butanol.VEis a collective effect of involvements namely,(i)rupture of coupled entities,of any of the constituent molecules; (ii) packing among the constituent molecules of the mixture and (iii) steric effects[43].While the processes (i) and (iii) contribute to positiveVE;factor (ii) yields negative values.The positiveVEvalues for diesel(2) + 1-propanol (3) blends suggest thatVEcontribution due to factors (i) and (iii) is dominating over factor (ii).It may be due to strong intermolecular hydrogen bonds in 1-propanol and thus require more energy to rupture intermolecular hydrogen bonding.However,VEdata for diesel(2)+1-butanol(3)blends suggest that addition of diesel to 1-butanol up tox2≤0.2984 dominates the contribution due to rupture of intermolecular hydrogen bonding in 1-butanol and afterx2≥0.2984 there is effective packing among the diesel and 1-butanol molecules.The (?VE/?T) of said binary blends are positive.

Thefor ternaryJ.curcasbiodiesel (1) + diesel (2) + 1-propanol (3) blends are positive as a function of composition at the investigated temperatures.However,data forJ.curcasbiodiesel (1) ＋diesel (2) + 1-butanol (3) blends are negative across entire composition of 1 and 2 components at 288.15,293.15,298.15 K and from 303.15 to 313.15 K the sign and magnitude ofchanges to relative proportion of composition ofx1andx2.Thedata for ternary blends indicate that diesel gives relative effective packing inJ.curcasbiodiesel:1-butanol as compared toJ.curcasbiodiesel:1-propanol molecular entity.Thevalues for the ternary blends are increasing with increase in temperature.

4.Conclusions

Consumption of non-renewable fuel sources has created the need to adopt alternative renewable energy sources,such as biodiesel.In the present studies,we measured densities of binary diesel (2) + 1-alkanols (C3or C4) (3) and ternaryJ.curcasbiodiesel(1)+diesel(2)+1-alkanols(C3or C4)(3)blends over full mole fraction range at temperature from 288.15-313.15 K and atmospheric pressure and determined their excess molar volumes,VE,utilizing measured data.The ρ of diesel(2)+1-alkanols(C3or C4)(3)blends increase with rise in concentration of diesel and decrease with rise in temperature or vice-versa.The lower densities values of binary diesel(2)+1-propanol(3)blends in comparison to diesel indicated that binary blend may act as better fuel than parent diesel.Further,the densities of ternaryJ.curcasbiodiesel (1) + diesel(2) + 1-alkanols (C3or C4) (3) blends are lower than those for binaryJ.curcasbiodiesel(1)+diesel(2)binary blends.Thedata of the ternary blends suggest that diesel gives more packed packing with biodiesel:1-propanol in comparison to biodiesel.

Declaration of Competing Interest

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

Acknowledgements

V.K.Sharma and Dr.Sunita are grateful to CSIR for the award of Emeritus Scientist and Research Associate (Reference No.21(1061/18/EMR-II).Ms.Poonam Jangra Darolia is also thankful to CSIR for JRF.

Supplementary Material

Supplementary data to this article can be found online at https://doi.org/10.1016/j.cjche.2020.09.065.