Ola PD et al./Journal of Applied Chemical Science 2013, VoL. 2 Issue 2: 267-272 Available online at www.jacsonline.org

ISSN: 2089-6328 Research Article

The Optimum Condition for Synthesis of Biodiesel from Castor (Ricinus communis) Oil through Transesterification Reaction Pius Dore Ola, Ria A. Karim, and Maria F. Suherdin Department of Chemistry Faculty of Science and Engineering, Nusa Cendana University

ABSTRACT The optimum conditions of transesterification reaction to provide biodiesel from castor (Ricinus communis) oil had been conducted and the biodiesel viscosity, density, free fatty acid content and acid number were compared with Bureau of Indian Standard (BIS). The total oil of castor seed was extracted using petroleum eter, and followed by neutralization using Na2CO3 35 % (b/v) and the transesterification reaction is by variations in amount of methanol (10, 15, 20 and 25 g), NaOH (0.5; 1.0 and 1.5 g), the time of reaction (30, 60, 90 and 120 minute) and the temperature of reaction (30, 45 dan 60 OC). The result showed that extraction process produce oil of castor in amount of 70 - 80 % in rendement, while neutralization proces produced 74.66 % of rendement with decreasing in content of free fatty acid from 1.7 to 0.1. The optimum conditions of reaction for 100 g of castor oil are 20 g of methanol, 1.5 g of NaOH, 60 minute in reaction time and 30 OC in temperature reaction. The purity of biodiesel yielded is between 93.46 – 96.26 % and all of them agree with the BIS and except for viscosity. Keywords: Ricinnus communis, transesterification, biodiesel, BIS

Introduction Diminishing of fuel fosill stock, high cost of raw materials, harmful of fossil fuel emitions and high demand of fuel are problem for each country in the world. Energy sources from renewable resources is a better alternative because it is easy to obtained and also environmentally friendlier. One of energy sources from renewable resources is biodiesel. Biodiesel is a methyl or ethyl ester of fatty acid made from renewable biological resources such as vegetable oils (both edible and nonedible), recycled waste vegetable oil and animal fats (Demirbas, 2000; Kinney and Clemente, 2005; Wilson et al., 2005). It is derived from the transesterification reaction. This process consisted of combining an oil (typically vegetable oil) with a light alcohol. The glycerol byproduct from the reaction is obtained that can be used by various industries including cosmetics industry (Marin and Garcia, 2012). Previous report shown that there has been reviewed a range of vegetable resources, including sunflower, cotton seed, rape seed, soybean, palm and peanut oils and their usefulness, for biodiesel production (Shahid and Jamal 2008). They concluded that using a mixture of petroleum diesel and biodiesel, at an 80:20 ratio (B20), was the most successful. However, vegetable oils cannot often be used directly as an energy source in an engine due to the higher level of viscosity, the lower volatility and the reactivity of the

unsaturated hydrocarbon chains within oils (Demirbas, 2009 and Usta et. al. 2005). Many technologies and methods have been employed to try and reduce the viscosity of the oil; these include microemulsion, pyrolysis (thermal cracking), catalytic cracking and transesterification (Bajpai and Tyagi, 2006, Ma and Hanna, 1999, Sharma, et.al., 2008). Amongst those four techniques, the transesterification is the most promising solution. The transesterification of oil with alcohol in the presence of a catalyst produced biodiesel and glycerol. The reaction is normally a sequence of three consecutive reversible reactions Marchetti et.al., 2007). In this process triglyceride is converted stepwisely into diglyceride, monoglyceride, and, finally, glycerol in which 1 mol of alkyl esters is formed in each step (Helwani et.al., 2009). The transesterification reaction were reported in Figure 1. (Muniyappa et.al., 1996). Castor (Ricinus communis) seed with content of oil reach 54 % (Silvio, 2002) is a potential renewable resources for energy sources. Nowdays, oil of Ricinus communis is not used as biodiesel but as lubricant only because it has high level viscosity. Therefore, research to reduce the viscosity of the oil, in order that-could be used as biodiesel-is an interesting topic. However, the current study was performanced to provide optimum conditions of transesterification to yield the synthetic biodiesel from castor oil.The yield of biodiesel in the process of transesterification is affected by several parameters which

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Ola PD et al./Journal of Applied Chemical Science 2013, VoL. 2 Issue 2: 267-272 include: presence of moisture and free fatty acids (FFA), reaction time, reaction temperature, catalyst and molar ratio of alcohol and oil (Parawira, 2010). Amongst of those factors, four of them were studied which was involved to find the optimum condition of number of methanol, number of NaOH (as catalyst), time and temperature of reaction. Main natures of biodiesel were evaluated and compared with Bureau of Indian Standard (BIS).

Fig. 1. Transesterification reaction of triglyceride

Materials and Methods 1. Chemicals Sample of Ricinus communis seed was obtained from Timor island-Indonesia. Sodium hydroxide (NaOH) pellets, methanol, petroleum eter (PE), sodium sulphate (Na2SO4) anhidrat and sodium carbonate (Na2CO3) were supplied by Merck. All chemicals were in the grade of pro anlysis (p.a). Aquabides was used for preparing the chemical solutions. 2. Ricinus comunnis oil extraction Weigh 100 g seed of Ricinus communis and refined it with blender. Refined seed was wraped with filtration paper. Lower and upper of it were closed with free fat of cotton. Encasement was put into soxhlet. Added PE amount 60 % of flask volume and extraction was done for 2.5 hours. Na2SO4 anhidrous was added to the product of extraction and then evaporated. The oil produced was identified its colour and odor and determined its density and acid number. 3. Oil Neutralization Amount 100 g of oil was disolved in 100 mL of PE and put into separation funnel. Added 100 mL of Na2CO3 35 % (b/v) solution while shake slowly. Yellow gelatine that formed under part of layer was separated. Amount 100 mL Na2CO3 35 % (b/v) was added again to upper part of layer then washed with aquabides until neutral (pH = 7). The yelow liquid produced from this process was Page | 268

then dried with Na2SO4 anhidrated and evaporated. Acid number of the oil was determined. Neutralization process was repeated until the acid number of oil was almost zero. 4. Transesterification Transesterfication was done by adding a variety amount both NaOH and methanol to the three neck flask that was equipped with condensor and thermometer and stirred until all of NaOH was disolved. Amount 100 g of oil was added and mixture was stirred at variety of time and temperature. The mixture was put into separated flask and left it for 12 hours. Methyl ester that produced from this process was washed with water until neutral (pH =7). Product obtained from each optimum conditions was analysis with GCMS. 5. Biodiesel Nature Evaluation Viscosity of methyl ester was tested with ASTM 445-72 method. Its density was determined with IS: 1448-1972 method, and chemical nature as free fatty acid and acid number were evaluated with American Oil Chemical Society Ca 50-40 method.

Results and Discussion 1. Extraction Extraction of 100 g of Ricinus communis seed with 300 mL of PE produced 78 to 80 g of oil. Physically and Chemically character of oil is shown in Table 1. Table 1. Physically and Chemically character of oil Physically and Chemically character Result Colour yellow Odor odorless Density (g/mL) 0.83 Acid number 1.024 Refraction index 1.479 (24.6°C)

2. Neutralization The aimed of neutralization is to remove both free fatty acid and another polluter as sterol, gelatine etc that could disturb transesterification process. Neutralization is done by adding of Na2CO3 35 % into the separation funnel that contain 50 g of oil. The two layers resulted in the mixture indicated the oil (upper) and polluter (below) layers. Na2CO3 solution is weak base so it could neutralize free fatty acid only but could not hydrolis the triglyseride. Reaction of neutralization is written as in Fig. 2. Rendement yielded from this process was 74.66 % and the free fatty acid content decrease from 1.7 to 0.1.

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Ola PD et al./Journal of Applied Chemical Science 2013, VoL. 2 Issue 2: 267-272

Fig. 2. Neutralization reaction of free fatty acid

3. Transesterification Transesterification is done by mixing 100 g of oil with methanol in variation of mass and 1 g of NaOH. Temperature and time of reaction are set at 60 OC for 120 minutes. The optimum mass of methanol obtained from this experiment would be used in the experiment to find the optimum number of NaOH. Both methanol and NaOH optimum mass would be used to investigate the optimum of reaction time. Then, the optimum of reaction temperature was evaluated by using of optimum number of methanol, NaOH and time that previously obtained. The result is shown in Fig. 3. The result showed that, the optimum number of methyl ester in each experiment was obtained at 20 g of methanol (84,72 g), 1.5 g of NaOH (95.38 g), 60 minute (87.97 g) of reaction time and 30 oC (95.12 g) of reaction temperature. Purity of methyl ester was determined with chromatography-mass spectroscopy (GCMS). Chromatograms of each component are shown in Figure 4. These chromatograms showed

that product of transesterfocation consisted of five, eight, six and five compounds in variation of methanol mass, NaOH mass, time and temperature respectively. The highest content in each experiment has retention time 27.143, 27.318, 29.035 and 29.235 minutes with purity level in rangings of 93.46 to 96.26 %. Based on the spectra of mass spectroscopy these compounds are estimated as methyl ester of ricinoleic acid. Difference in retention time is because of diffrence in condition of reaction. One of the spectra of mass spectroscopy is shown in Figure 4. In this spectra similarity index of the sampel to the standard reach 92 %. Although, mass spectra does not display the peak of ion molecular (m/z = 132), however, another peaks of it are evidence that, this cmpound is methyl ricinoleic acid. These peaks are appeared from fragmentation of methyl ricinoleic acid as shown in figure 5. Base peak (m/z = 55) is from rearrangement of Mc.Lafferty and is followed by α splitting.

Fig. 3. The number of methyl ester produced in variation of methanol (a), NaOH (b), time (c), and temperature (d)

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Ola PD et al./Journal of Applied Chemical Science 2013, VoL. 2 Issue 2: 267-272

Fig. 4. Chromatogram of transesterification product at optimum condition: mass of methanol (a), mass of NaOH (b), time of reaction (c) and temperature of reaction(d)

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Ola PD et al./Journal of Applied Chemical Science 2013, VoL. 2 Issue 2: 267-272 Fig. 4. Mass spectra of compound with 27.143 minute of retention time

Fig. 5. Fragmentation pattern of methyl ricinoleic acid

Table 2. Compounds in the product of transesterification by variation in mass of methanol tR (minutes) Compounds Content (%) 20.05 Methyl ester of 14-methyl pentadecanoic acid 0.8 20.38 Methyl ester of linoleic acid 2.63 6.677 Methyl ester of elaidic acid 2.20 6.842 Methyl ester of stearic acid 0.9 27.143 Metyl ester of ricinoleic acid 93.46 . Table 3. The characteristic of biodiesel produced in each optimum condition At optimum Number of Number of Time condition methanol NaOH 9.26 10.24 12.46 Viscosity (40 oC) cSt 0.896 0.881 0.898 Density % Free Fatty acid 0.357 idem idem 0.684 idem idem Acid number

Based on the mass spectra, five compounds in the product of transesterification has succesfully identified and its result is listed in Table 2. The characteristics of methyl ester produced in each optimum condition are listed in Table 3 4. Nature test of Biodiesel The characteristic of methyl ester produced in each optimum condition is evaluated as biodiesel and is compared to the BIS (Bereau Indian Standard). The result of comparison are listed in Table 4. The data reported in Table 4 shows that

Temperature 7.1 0.911 idem idem

biodiesel produced in transesterification of ricinus communis oil in each optimum condition agree with BIS except viscosity. Conclusions: The optimum condition of the transesterification reaction in production of biodiesel from 100 g of Ricinus communis oil were 20 g of methanol, 1.5 g of NaOH, reaction is occured at 30°C for 60 minute. Biodiesel produced and purities of ricinoleic metyl ester are in ranges of 84.72 to 95.38 g and 93.46 to 96.26 %, respectively. The biodiesel produced agree with the BIS standard but except for the viscosity.

Table 4. The characteristics of the biodiesel resulted versus BIS Type of biodiesel Viscosity (40°C) cSt Density Synthetic biodiesel (castor oil) 7.10 – 12.46 0.88 – 0.91 BIS 3.5 – 5.0 0.87-0.9

% Free Fatty acid 0.357 < 0.5

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Acid number 0.684