Variables affecting the yields of methyl esters derived from <i>in situ</i> esterification of rice bran oil

Yücel, Sevil; Türkay, Selma

doi:10.1007/s11746-002-0531-5

Cited by 70 publications

(29 citation statements)

References 5 publications

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“…Generally, reaction time is an important factor that affects alkali-catalyzed in situ transesterification, and triglyceride conversion increases at longer reaction time [23,25,29,30,47]. Nevertheless, within the 3-5 h reaction time investigated in this study, increasing this parameter did not systematically increase the biodiesel yield, as previously reported by Ozgul-Yucel and Turkay [51]. Instead, biodiesel yield remained relatively constant as the reaction time increased from 3 to 5 h, meaning that the equilibrium composition had already been achieved by the system after only 3 h. Normally, biodiesel yield reaches a maximum as reaction time increases (e.g.…”

Section: Resultssupporting

confidence: 75%

Biodiesel production from jatropha seeds: Solvent extraction and in situ transesterification in a single step

Kartika¹,

Yani²,

Ariono

et al. 2013

Fuel

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production from jatropha seeds: Solvent extraction and in situ transesterification in a single step. Fuel, Elsevier, 2013, vol. 106, pp. 111-117. <10.1016/j.fuel.2013 This is an author-deposited version published in: http://oatao.univ-toulouse.fr/ Eprints ID: 8587 " We investigate the biodiesel production directly from jatropha seeds. " We examine influences of reaction conditions on biodiesel yield and its quality. " Increasing methanol to seed ratio and alkali concentration will increase yield and quality. " Increasing reaction temperature will increase yield. " Temperature, time and stirring speed effects on biodiesel quality were less important. a r t i c l e i n f o b s t r a c tThe objective of this study was to investigate solvent extraction and in situ transesterification in a single step to allow direct production of biodiesel from jatropha seeds. Experiments were conducted using milled jatropha seeds, and n-hexane as extracting solvent. The influence of methanol to seed ratio (2:1-6:1), amount of alkali (KOH) catalyst (0.05-0.1 mol/L in methanol), stirring speed (700-900 rpm), temperature (40-60°C) and reaction time (3-5 h) was examined to define optimum biodiesel yield and biodiesel quality after water washing and drying. When stirring speed, temperature and reaction time were fixed at 700 rpm, 60°C and 4 h respectively, highest biodiesel yield (80% with a fatty acid methyl ester purity of 99.9%) and optimum biodiesel quality were obtained with a methanol to seed ratio of 6:1 and 0.075 mol/L KOH in methanol. Subsequently, the influence of stirring speed, temperature and reaction time on biodiesel yield and biodiesel quality was studied, by applying the randomized factorial experimental design with ANOVA (F-test at p = 0.05), and using the optimum values previously found for methanol to seed ratio and KOH catalyst level. Most experimental runs conducted at 50°C resulted to high biodiesel yields, while stirring speed and reaction time did not give significantly effect. The highest biodiesel yield (87% with a fatty acid methyl ester purity of 99.7%) was obtained with a methanol to seed ratio of 6:1, KOH catalyst of 0.075 mol/L in methanol, a stirring speed of 800 rpm, a temperature of 50°C, and a reaction time of 5 h. The effects of stirring speed, temperature and reaction time on biodiesel quality were not significant. Most of the biodiesel quality obtained in this study conformed to the Indonesian Biodiesel Standard.

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Section: Resultssupporting

confidence: 75%

Biodiesel production from jatropha seeds: Solvent extraction and in situ transesterification in a single step

Kartika¹,

Yani²,

Ariono

et al. 2013

Fuel

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“…Although we have investigated only soy flakes as a substrate here, general principles and prior reports using in situ acid catalysis (5)(6)(7)(8)(9) suggest that the technique will be applicable to other oilseeds as well. In addition, this process should lend itself to continuous operation, a desirable format that also may increase ester yields.…”

Section: Resultsmentioning

confidence: 99%

In situ alkaline transesterification: An effective method for the production of fatty acid esters from vegetable oils

Haas

Scott

Marmer

et al. 2004

J Americ Oil Chem Soc

182

115

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The production of simple alkyl FA esters by direct alkali-catalyzed in situ transesterification of the acylglycerols (AG) in soybeans was examined. Initial experiments demonstrated that the lipid in commercially produced soy flakes was readily transesterified during agitation at 60°C in sealed containers of alcoholic NaOH. Methyl, ethyl, and isopropyl alcohols readily participated in the reaction, suggesting that the phenomenon is a general one. Statistical experimental design methods and response surface regression analysis were used to optimize reaction conditions, using methanol as alcohol. At 60°C, the highest yields of methyl ester with minimal contamination by FFA and AG were predicted at a molar ratio of methanol/AG/NaOH of 226:1:1.6 with an approximately 8-h incubation. An increase in the amount of methanol, coupled with a reduced alkali concentration, also gave high ester yields with low FFA and AG contamination. The reaction also proceeded well at 23°C (room temperature), giving higher predicted ester yields than at 60°C. At room temperature, maximal esterification was predicted at a molar ratio of 543:1:2.0 for methanol/AG/NaOH, again in 8 h. Of the lipid in soy flakes, 95% was removed under such conditions. The amount of FAME recovered after in situ transesterification corresponded to 84% of this solubilized lipid. Given the 95% removal of lipid from the soy flakes and an 84% efficiency of conversion of this solubilized lipid to FAME, one calculates an overall transesterification efficiency of 80%. The FAME fraction contained only 0.72% (mass basis) FFA and no AG. Of the glycerol released by transesterification, 93% was located in the alcoholic ester phase and 7% was on the post-transesterification flakes.Paper no. J10571 in JAOCS 81, 83-89 (January 2004).KEY WORDS: Biodiesel, fats and oils utilization, fatty acid ester, in situ transesterification, transesterification.The simple alkyl esters of FA have numerous established uses in the food, textile, cosmetic, rubber and metal processing, and synthetic lubricant industries. FAME are the predominant esters consumed, with a year 2000 global consumption of 1 million metric tons (MMT) (1). In addition, FAME are the favored starting material for the production of fatty amides, more complex esters, ester sulfonates, and fatty alcohols. Fatty alcohols alone were consumed at a world rate of 6.2 MMT in 2000 (1). Production and consumption of the methyl esters of FA are rapidly increasing due to their growing use as biodiesel, a renewable replacement for petroleum-based diesel engine fuel.Contemporary industrial technology for the synthesis of fatty acyl esters of vegetable oils involves isolation of oilseed acylglycerides by extrusion or solvent extraction, degumming and refining of the oil, and its alkali-catalyzed transesterification. Hexane extraction is the main technology for oil recovery in the United States. Extraction plants achieve high levels of solvent recovery, with a typical soybean processing plant losing less than 1.25 L of solvent per metric to...

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“…Stabilization of the bran is vital in maintaining the quality of the extracted oil for food use. Alternatively, a high-FFA oil level may be desirable for biodiesel production by the manufacture of FAME from rice oil (1). The in situ methanolic esterification of high-FFA rice bran oil to produce methyl esters for biodiesel produces greater yields than using low-FFA rice bran (1).…”

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confidence: 99%

Rice bran FFA determination by diffuse reflectance IR spectroscopy

Yücel

Proctor

2004

J Americ Oil Chem Soc

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Rice bran with FFA levels above 0.1% cannot be used as a food ingredient due to oxidative off-flavor formation. However, extracting high FFA oil from bran by in situ methanolic esterification of rice bran oil to produce methyl ester biodiesel produces greater yields relative to low-FFA rice bran oil. Therefore, high-FFA bran could be exploited for biodiesel production. This study describes an FTIR spectroscopic method to measure rice bran FFA rapidly. Commercial rice bran was incubated at 37°C and 70% humidity for a 13-d incubation period. Diffuse reflectance IR Fourier transform spectra of the bran were obtained and the percentage of FFA was determined by extraction and acid/base titration throughout this period. Partial least squares (PLS) regression and a calibration/validation analysis were done using the IR spectral regions 4000-400 cm −1 and 1731-1631 cm −1 . The diffuse reflectance IR Fourier transform spectra indicated an increasing FFA carbonyl response at the expense of the ester peak during incubation, and the regression coefficients obtained by PLS analysis also demonstrated that these functional groups and the carboxyl ion were important in predicting FFA levels. FFA rice bran changes also could be observed qualitatively by visual examination of the spectra. Calibration models obtained using the spectral regions 4000-400 cm −1 and 1731-1631 cm −1 produced correlation coefficients R and root mean square error (RMSE) of cross-validation of R = 0.99, RMSE = 1.78, and R = 0.92, RMSE = 4.67, respectively. Validation model statistics using the 4000-400 cm −1 and 1731-1631 cm −1 ranges were R = 0.96, RMSE = 3.64, and R = 0.88, RMSE = 5.80, respectively.

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Variables affecting the yields of methyl esters derived from in situ esterification of rice bran oil

Cited by 70 publications

References 5 publications

Biodiesel production from jatropha seeds: Solvent extraction and in situ transesterification in a single step

Biodiesel production from jatropha seeds: Solvent extraction and in situ transesterification in a single step

In situ alkaline transesterification: An effective method for the production of fatty acid esters from vegetable oils

Rice bran FFA determination by diffuse reflectance IR spectroscopy

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