Measurements and Correlations of Density, Viscosity, and Vapor

Article pubs.acs.org/jced

Measurements and Correlations of Density, Viscosity, and Vapor Pressure for Methyl Ricinoleate Ying Duan, Yong Nie,* Ruchao Gong, Shangzhi Yu, Dongshun Deng, Meizhen Lu, Ping Chen, and Jianbing Ji Zhejiang Province Key Lab of Biofuel, Zhejiang University of Technology, Hangzhou, Zhejiang 310014, China ABSTRACT: The density and viscosity of methyl ricinoleate were measured in the temperature range from (293.16 to 383.23) K and (298.23 to 358.15) K, respectively. The vapor pressure of methyl ricinoleate was determined using a static method in the temperature range of (451.58 to 476.80) K at the pressure between (232 and 868) Pa, and methyl palmitate was employed to examine the reliability of the experimental apparatus. The experimental data were compared with the open data for methyl ricinoleate and other fatty acid methyl esters with similar molecular weight. Temperature-dependence correlation equations for the density, viscosity, and vapor pressure were proposed.

1. INTRODUCTION

vapor pressure of methyl ricinoleate at different temperatures has rarely been reported. In this work, the density and viscosity of methyl ricinoleate were measured at temperatures ranging from (293.16 to 383.23) K and (298.23 to 358.15) K, respectively. The saturated vapor pressures of methyl ricinoleate were measured in the temperature range of (451.58 to 476.80) K. The relationships of density, viscosity, and vapor pressure with temperature were correlated. Moreover, the experimental data were compared with the open data of other fatty acid methyl esters with similar molecular weight.

Owing to the environment friendly source and consumption, biodiesel is an ideal substitute for conventional diesel.1 Castor oil is one of the world’s 10 major oils and four nonedible oils. Castor oil-based biodiesel has very important economic and social value, especially in China2 which is rich in castor oil and the second largest castor oil production country in the world. At present, biodiesel is used by being blended with petrodiesel in some countries.3 Therefore, many studies have been devoted to the measurement and prediction of the density, viscosity, and vapor pressures of biodiesel fuel as a function of temperature.4,5 The density and viscosity of the fatty acid methyl esters (FAME) from castor oil have been reported by Ustra et al.6 Ndiaye et al.7 measured the vapor pressure of the fatty acid ethyl esters (FAEE) in a temperature range of (290 to 355) K. However, the properties data of the pure compounds of biodiesel are more important, especially for several models which were proposed to estimate biodiesel fuel density and viscosity.8,9 Methyl ricinoleate produced by transesterification of castor oil with methanol is the main component of the castor oil-based biodiesel.10 The measurement of density, viscosity, and vapor pressure of methyl ricinoleate is necessary to predict biodiesel properties. In addition, castor oil is the only vegetable oil containing hydroxy in nature, methyl ricinoleate is also an important chemical intermediate for the bioproduction of perfumes, drugs, polymers, and other fine chemicals.11−14 Therefore, the preparation, purification, storage, and transportation of chemical raw materials also need the properties of methyl ricinoleate. Knothe et al.15−17 have measured the viscosity of pure methyl ricinoleate at low temperatures from (−10 to 40) °C. However, the viscosity of methyl ricinoleate at higher than 40 °C temperatures together with the density and © 2016 American Chemical Society

2. EXPERIMENTAL SECTION 2.1. Materials. Commercial castor oil (C.P.) and palm oil (C.P.) were supplied by Haishuo Biological Co.Ltd. (Wuxi, Jiangsu, China). Methanol (A.R.) and potassium hydroxide (A.R.) were from Juhua Company (Quzhou, Zhejiang, China). Ethylene glycol (A.R.) and methyl undecanoate (A.R.) were purchased from Aladdin Biochemical Technology Co. Ltd. (Shanghai, China). Table 2 shows information on these compounds. 2.2. The Synthesis and Purification of Methyl Ricinoleate and Methyl Palmitate. The methanol solution of potassium hydroxide (3.5 g of KOH:150 g of CH3OH) was added to castor (500 g) or palm (460 g) oil which was preheated to 60 °C, with the reaction kept at 60 °C for 1 h. After the glycerol phase was separated, the oil phase was washed with water to pH = 7 and the product was obtained after residual methanol and water were removed. Methyl ricinoleate or methyl palmitate was then Received: July 2, 2015 Accepted: January 15, 2016 Published: February 2, 2016 766

DOI: 10.1021/acs.jced.5b00545 J. Chem. Eng. Data 2016, 61, 766−771

Journal of Chemical & Engineering Data

Article

The densities of pure water and ethylene glycol were both obtained from the literature.19 Viscosity Measurements. Kinematic viscosities (ν) were measured by a capillary viscometer calibrated with pure water in the corresponding experimental temperature range at atmospheric pressure.18 The capillary was 0.80 mm in diameter and the same viscometer was used for all measurements. The viscometer soaked vertically in a thermostat bath and the temperature measuring device was mercury thermometer. The viscosities of methyl ricinoleate were calculated from the eq 2.

purified using a packed tower distillation unit under a reduced pressure ( 0.98 > 0.99 0.97 0.99 > 0.99 > 0.99



Article

Table 3. Experimental Density ρexp for Methyl Ricinoleate Compared with ρcal Calculated by eq 3 at the Temperature Range from (293.16 to 383.23) Ka under 101 100 Pa (Standard Uncertainty of Pressure Was 1.03 kPa)

a b

T

ρexp

ρcal

T

ρexp

ρcal

K

g·cm−3

g·cm−3

δρb

K

g·cm−3

g·cm−3

δρb

293.16 303.17 313.33 323.05 333.25

0.9285 0.9212 0.9167 0.9103 0.9040

0.9275 0.9219 0.9156 0.9090 0.9014

0.1097 −0.0752 0.1168 0.1414 0.2883

343.32 353.06 363.38 373.26 383.23

0.8958 0.8833 0.8750 0.8658 0.8575

0.8933 0.8849 0.8753 0.8655 0.8551

0.2755 −0.1847 −0.0320 0.0297 0.2884

Standard uncertainty u is u(T) = 0.04 K, and the combined expanded uncertainty Uc is Uc(ρ) = 0.007 g·cm−3 with 0.95 level of confidence (k ≈ 2). δρ = 102(ρexp − ρcal)/ρexp.

Table 4. Experimental Viscosities (νexp, mm2·s−1) for Methyl Ricinoleate Compared with νcal Calculated by eq 4 at Temperature from (298.23 to 358.15) Ka under 101 130 Pa (Standard Uncertainty of Pressure Was 1.04 kPa)

a

T

νexp

νcal

T

νexp

νcal

K

mm2·s−1

mm2·s−1

δνb

K

mm2·s−1

mm2·s−1

δνb

298.23 303.13 308.25 313.15 318.38 323.08 328.12

29.50 23.49 18.05 14.87 12.05 10.13 8.52

29.67 23.19 18.29 14.82 12.05 10.13 8.52

−0.58 1.30 −1.33 0.31 0.00 −0.01 −0.02

333.15 338.05 343.10 348.06 353.11 358.15

7.25 6.26 5.43 4.76 4.20 3.73

7.25 6.26 5.43 4.76 4.20 3.73

−0.02 −0.03 −0.03 −0.04 −0.04 −0.05

Standard uncertainty u is u(T) = 0.04 K, and the expanded combined relative uncertainty Uc,r(ν) = 3.17%. bδν = 102(νexp − νcal)/ νexp.

Figure 1. Scheme of the apparatus: 1, superthermostat; 2, balance tube; 3, condenser; 4, manometer; 5, pumping valve; 6, balancing valve; 7, freeze-dryer; 8, vacuum; 9, mercury thermometer.

Figure 2. Comparison between the density experimental data of methyl ricinoleate from this work and those of methyl stearate, methyl arachidate, and methyl gadoleate in previous studies.8,9 The density data of FAME from castor oil was obtained by literature.6

3. RESULTS AND DISCUSSION 3.1. Density. Density versus temperature was correlated to a second-order polynomial (eq 3), and the correlation coefficient R for density Rρ is 0.9955. The experimental data and calculated values of density at temperatures ranging from (293.16 to 383.23) K and the relative deviations of density between the measured data and those calculated by eq 3 are present in Table 3, and the maximum deviation is 0.0024 g·cm−3. Therefore, eq 3 can predict the experimental data of density very well.

methyl gadoleate in previous studies.8,9 Seen from Figure 2, the density of methyl ricinoleate decreased gradually with the increase of temperature, which was similar to that of the other three methyl esters. The density of methyl ricinoleate is higher than that of methyl stearate, methyl arachidate, and methyl gadoleate at the same temperature. Methyl ricinoleate and methyl stearate have the same alkyl chain length, while the density of methyl ricinoleate is higher than that of methyl stearate. This maybe due to the unsaturated bond and hydroxyl radical of methyl ricinoleate. Surprisingly methyl ricinoleate presents a higher value for density than the corresponding methyl arachidate and methyl gadoleate with the larger alkyl chain length. This suggests that the existence of hydroxyl radical greatly influenced the density of methyl ricinoleate. 3.2. Viscosity. Viscosity versus temperature was fitted to the Walther equation20 shown in eq 4. Equation 4 suggests that a graph of log log(viscosity + 0.8) versus log(temperature) shown

ρ /g·cm−3 = 0.817 + 1.28 × 10−3(T /K) − 3.081·10−6(T /K)2

(3)

In the family of fatty acid methyl esters, the molecular weight of methyl stearate, methyl arachidate, or methyl gadoleate is similar to the molecular weight of methyl ricinoleate. Figure 2 compared the density experimental data of methyl ricinoleate in this work with those of methyl stearate, methyl arachidate, and 768



Article

Table 6. Experimental Vapor Pressures of Methyl Ricinoleatea T/K

Pexp/Pa

T/K

Pexp/Pa

T/K

Pexp/Pa

451.58 454.70 457.23 459.50 461.85

232 276 319 361 410

463.55 465.20 466.83 469.55 470.40

449 490 533 610 637

471.25 472.30 473.15 474.90 476.80

665 700 730 794 868

a

Standard uncertainties are u(T) = 0.04 K and the expanded combined relative uncertainty Uc,r(P) = 11.6%.

Table 7. Parameters of Equations for Methyl Ricinoleate parameters A B C

Figure 3. Correlation line from eq 4 and the comparison of experimental value between this work and relevant references.

D1 D2 D3 D4

value Equation 5 18.308 −2828.559 −231.725 Equation 6 −197.509 408.448 −463.728 504.617

RMSDa

R

0.53

0.9999

0.11

0.9999

1/2 1 n Calculated as RMSD = ⎡⎣ n ∑1 (expi − cali)2 ⎤⎦ where expi is the experiment value of number i; cali represents the value calculated from the correlation equation; n is the number of experimental points. a

Figure 4. Comparison between the dynamic viscosity experimental data of methyl ricinoleate from this work and those of methyl stearate, methyl arachidate, and methyl gadoleate in previous studies,8,9 respectively. The viscosity data of FAME from castor oil was obtained by literature6

in Figure 3 is a straight line, and the correlation coefficient Rν is 0.9999. The relative deviations for viscosity data calculated from eq 4 listed in Table 3 were determined to be consistent within 1.33%, whereas the maximum deviation was 0.24 mm2·s−1. The results reveal that eq 4 can represent the experimental viscosity data very well. Seen from Figure 3, experimental value of methyl ricinoleate viscosity from refs 15 and 16 were compared with that of this work, and the value of references are all on the correlation line from eq 4. The viscosity relative deviation of methyl

Figure 5. Relative deviations of pressures between experimental Pexp and calculated Pcal by the Antoine eq (eq 5) and by the Wagner eq (eq 6).

ricinoleate between this work and references were less than 2.85%.

Table 5. Experimental Vapor Pressures of Methyl Palmitate Compared with Pref Calculated by the Antoine Constantsa from Literature21

a

T/K

Pexp/Pa

Pref/Pa

δPb

T/K

Pexp/Pa

Pref/Pa

δPb

407.12 414.26 418.18 422.34 424.68 427.54 429.32 432.32

130 210 240 270 305 365 415 420

135 195 237 290 324 371 403 463

−4.23 7.20 1.38 −7.31 −6.25 −1.64 2.85 −10.29

434.18 437.30 438.44 439.60 441.00 445.36 447.06

515 545 560 650 660 840 850

504 581 611 644 685 828 891

2.07 −6.55 −9.13 1.00 −3.74 1.38 −4.87

Standard uncertainties u are u(T) = 0.04 K, the expanded combined relative uncertainty Uc,r(P) = 11.2%. bδP = 102(Pexp − Pref)/Pexp. 769



Article

or the Wagner eq (eq 6) were consistent within ±0.50%. Therefore, it is proven that eq 5 and eq 6 basically satisfy the requirements for application in the chemical engineering. Figure 6 presents the comparison between the experimental data of vapor pressures versus temperature for methyl ricinoleate in this work and those of methyl stearate and methyl arachidate in previous studies.21,23 Under the same vapor pressure, the boiling point of methyl ricinoleate is between that of methyl stearate and methyl arachidate. The boiling point is generally related to the action of molecules. It is expected that methyl arachidate shows a higher boiling point result from its higher molecular weight. Although methyl ricinoleate and methyl stearate have the same alkyl chain length, because of the hydroxyl radical of methyl ricinoleate, the boiling point of methyl ricinoleate is higher than that of methyl stearate.

Figure 6. Comparison between the experimental data of vapor pressures versus temperature for methyl ricinoleate from this work and those of methyl stearate and methyl arachidate in previous studies,21,23 respectively.

4. CONCLUSIONS The density data for methyl ricinoleate in the temperature range of (293.16 to 383.23) K were fitted to the second-order polynomial. The viscosity versus temperature in the range of (298.23 to 358.15) K was fitted to the Walther equation. The vapor pressure in the temperature range of (451.58 to 476.80) K at the pressure between (232 and 868) Pa were fitted to the Antoine and Wagner equations. In addition, the experimental data were compared with the open data of other fatty acid methyl esters with similar molecular weight.

log log(ν/mm 2·s−1 + 0.8) = 11.198 − 4.456 log(T /K) (4)

Dynamic viscosities (η) of methyl ricinoleate calculated from η = υ/ρ were obtained and compared with the dynamic viscosity experimental data of methyl stearate, methyl arachidate, and methyl gadoleate from the open literature,8,9 as shown in Figure 4. As expected, the viscosity of methyl ricinoleate was larger than that of methyl stearate, methyl arachidate, and methyl gadoleate at the same temperature. The hydroxyl radical of methyl ricinoleate also shows the larger impact on the viscosity. The viscosity data of FAME from castor oil was obtained by literature.6 The content of methyl ricinoleate in FAME from castor oil was about 89 wt %, which made the viscosity values lower than that of the pure methyl ricinoleate (>99 wt %). The same result also occurred for the density shown in Figure 2. 3.3. Vapor Pressures. To examine the reliability of the experimental apparatus, the vapor pressure of methyl palmitate was measured from (407.12 to 447.06) K, and the results were compared with the literature values21 listed in Table 5. The vapor pressures relative average deviation of methyl palmitate between the experimental results and the literature values21 was 4.66%, whereas the absolute deviations were less than 43 Pa. It indicated that the apparatus met the requirements for the measurement of vapor pressure of methyl ricinoleate. Vapor pressure versus temperature shown in Table 6 for methyl ricinoleate was fitted to the Antoine eq (eq 5) and Wagner eq (eq 6). ln(P /Pa) = A +

B C + T /K

⎛ P ⎞ (D τ + D2τ1.5 + D3τ 3 + D4 τ 6)Tc ln⎜ ⎟ = 1 T ⎝ Pc ⎠

■

AUTHOR INFORMATION

Corresponding Author

*Fax: +86-571-88320053. Tel:+86-571-88320646. E-mail: ny_ [email protected]. Funding

Financial support provided by the National High-tech Research and Development Program of China (863 Program; No.2014AA022103) is greatly acknowledged. Notes

The authors declare no competing financial interest.

■

REFERENCES

(1) Ma, F. R.; Hanna, M. A. Biodiesel production: a review. Bioresour. Technol. 1999, 70, 1−15. (2) Mutlu, H.; Meier, M. A. R. Castor oil as a renewable resource for the chemical industry. Eur. J. Lipid Sci. Technol. 2010, 112, 10−30. (3) Parajuli, R. J. Economics of biodiesel production in the context of fulfilling 20% blending with petro-diesel in Nepal. International Journal of Sustainable Energy. 2014, 33, 435−447. (4) Nogueira, C. A.; Feitosa, F. X.; Fernandes, F. A. N.; Santiago, R. S.; de Sant’Ana, H. B. Densities and Viscosities of Binary Mixtures of Babassu Biodiesel + Cotton Seed or Soybean Biodiesel at Different Temperatures. J. Chem. Eng. Data 2010, 55, 5305−5310. (5) Ceriani, R.; Goncalves, C. B.; Rabelo, J.; Caruso, M.; Cunha, A. C. C.; Cavaleri, F. W.; Batista, E. A. C.; Meirelles, A. J. A. Group Contribution Model for Predicting Viscosity of Fatty Compounds. J. Chem. Eng. Data 2007, 52, 965−972. (6) Ustra, M. K.; Silva, J. R. F.; Ansolin, M.; Balen, M.; Cantelli, K.; Alkimim, I. P.; Mazutti, M. A.; Voll, F. A. P.; Cabral, V. F.; Filho, L. C.; Corazza, M. L. Effect of temperature and composition on density, viscosity and thermal conductivity of fatty acid methyl esters from soybean, castor and Jatropha curcas oils. J. Chem. Thermodyn. 2013, 58, 460−466. (7) Ndiaye, P. M.; Tavares, F. W.; Dalmolin, I.; Dariva, C.; Oliveira, D.; Oliveira, J. V. Vapor Pressure Data of Soybean Oil, Castor Oil, and Their Fatty Acid Ethyl Ester Derivatives. J. Chem. Eng. Data 2005, 50, 330− 333.

(5)

(6)

where P is the vapor pressure in Pa, Pc is the critical pressure, τ is the dimensionless temperature defined by τ = (Tc − T)/Tc, T is the temperature in K, the critical temperature Tc = 894.07 K and pressure Pc = 1.25 MPa were estimated using Marrero and Pardillo’s method.22 The regressed parameters in eq 5 and eq 6 and the root-mean-square deviations (RMSD) are given in Table 7. Seen from Figure 5, the relative deviations of pressure between experimental data and those calculated by the Antoine eq (eq 5) 770



Article

(8) Pratas, M. J.; Freitas, S.; Oliveira, M. B.; Monteiro, S. C.; Lima, A. S.; Coutinho, JA. P. Densities and Viscosities of Fatty Acid Methyl and Ethyl Esters. J. Chem. Eng. Data 2010, 55, 3983−3990. (9) Pratas, M. J.; Freitas, S.; Oliveira, M. B.; Monteiro, S. C.; Lima, A. S.; Coutinho, JA. P. Densities and Viscosities of Minority Fatty Acid Methyl and Ethyl Esters Present in Biodiesel. J. Chem. Eng. Data 2011, 56, 2175−2180. (10) Kılıç, M.; Uzun, B. B.; Başak, B. U.; Pütün, E.; Pütün, A. E. Optimization of biodiesel production from castor oil using factorial design. Fuel Process. Technol. 2013, 111, 105−110. (11) Naughton, F. C. Production, Chemistry, and Commercial Applications of Various Chemicals from Castor Oil. J. Am. Oil Chem. Soc. 1974, 51, 65−71. (12) Ogunniyi, D. S. Castor oil: A vital industrial raw material. Bioresour. Technol. 2006, 97, 1086−1091. (13) Van der Steen, M.; Stevens, C. V. Undecylenic Acid: A Renewable Building Block from Castor Oil. ChemSusChem 2009, 2, 692−713. (14) Nie, Y.; Duan, Y.; Gong, R. C.; Yu, S. Z.; Lu, M. Z.; Yu, F. W.; Ji, J. B. Microwave-assisted pyrolysis of methyl ricinoleate for continuous production of undecylenic acid methyl ester (UAME). Bioresour. Technol. 2015, 186, 334−337. (15) Knothe, G.; Steidley, K. R. Kinematic viscosity of biodiesel components (fatty acid alkyl esters) and related compounds at low temperatures. Fuel 2007, 86, 2560−2567. (16) Knothe, G.; Steidley, K. R. Kinematic viscosity of biodiesel fuel components and related compounds. Influence of compound structure and comparison to petrodiesel fuel components. Fuel 2005, 84, 1059− 1065. (17) Teeter, H. M.; Cowan, J. C. Viscometric Properties of Higher Fatty Acids and Their Derivatives. J. Am. Oil Chem. Soc. 1956, 33, 163− 169. (18) Shao, X. Z.; Wu, J. S.; Zhang, G. Q.; Wang, L. S. Density, Viscosity, and Vapor Pressure of Phenyl Dichlorophosphite. J. Chem. Eng. Data 2008, 53, 1012−1014. (19) Perry, R. H.; Green, D. W.; Malone, J. O. Perry’s Chemical Engineers Handbook, 6th ed.; McGraw-Hill: New York, 1984. (20) Aboul-Seoud, A. L.; Moharam, H. M. A Generalized Viscosity Correlation for Undefined Petroleum Fractions. Chem. Eng. J. 1999, 72, 253−256. (21) Scott, T. J.; Macmillan, D.; Melvin, E. H. Vapor Pressures and Distillation of Methyl Esters of Some Fatty Acids. Ind. Eng. Chem. 1952, 44, 172−175. (22) Poling, B. E.; Prausnitz, J. M.; O’Connell, J. P. The Properties of Gases and Liquids, 5th ed.; McGraw-Hill: New York, 2001. (23) Weast, R. C.; Grasselli, J. G. CRC Handbook of Data on Organic Compounds, 2nd ed.; Boca Raton, FL, 1989.

771


Measurements and Correlations of Density, Viscosity, and Vapor

Recommend Documents