<i>In situ</i> esterification of rice bran oil with methanol and ethanol

Ozgul, S. Esra; Türkay, Selma

doi:10.1007/bf02542617

Cited by 51 publications

(19 citation statements)

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“…The data indicated that high-FFA bran is most suitable for in situ esterification. Methyl ester synthesis increased with increase in initial FFA content, confirming our earlier report (8). Furthermore, the purity of methyl esters was greater in oil with higher FFA content.…”

Section: Resultssupporting

confidence: 90%

“…The total bran oil was determined in duplicate by Soxhlet extraction of the bran prior to in situ esterification. Samples were esterified in situ in duplicate according to the method of Özgül and Türkay (8). Rice bran (50 g) was mixed with 200 mL methanol and 5 mL of concentrated sufuric acid and refluxed for 1 h. The mixture was vaccum-filtered, and the retained material was washed with 100 mL methanol and dried overnight at room temperature.…”

Section: Methodsmentioning

confidence: 99%

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

Yücel

Türkay

2002

J Americ Oil Chem Soc

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The influence of specific factors on in situ methanolic esterification of rice bran oil (RBO) using sulfuric acid catalyst was investigated. Using high-FFA rice bran was found to be the most effective means to increase methyl ester yields. The ester content of the extract increased about 67% when the FFA content of oil was increased from 16.6 to 84.5%. Increasing the reaction time beyond 30 min did not affect yields. Increasing the temperature from 20 to 65°C elevated the FAME yield by about 30%, but increasing the amount of acid catalyst above 5 mL did not enhance yield, and increasing the methanol dose from 200 to 250 mL had a negligible effect.Paper no. J10128 in JAOCS 79, 611-614 (June 2002). KEY WORDS:Esterification, fatty acid, fatty acid methyl esters, in situ esterification, rice bran, rice bran oil. FAME are used, rather than FA, to produce a number of FA derivatives such as fatty alcohols, alkanolamides, α-sulfonated methyl esters, and sucrose esters because FAME are more stable, less corrosive, and more easily fractionated (1). Methyl esters have recently been used as a diesel additive and clean energy source in Europe (2) but are currently not competitive with diesel fuel prices. However, relatively inexpensive raw materials such as soapstock, agricultural wastes, tallow, and high-FFA-containing greases are being used, which may reduce production costs (3-5). In this study, factors affecting FAME production from rice bran oil (RBO), an inexpensive rice co-product, were investigated. Production costs may be further reduced by in situ esterification, i.e., simultaneous oil extraction and methyl esterification. In situ esterification was first performed by transesterification of sunflower seed oil with acidified methanol, and it resulted in a significant methyl ester yield (6,7). High-acidity oils, such as rice bran oil (RBO), can readily form FAME during extraction (8), and methanol acts as both an extraction solvent and reagent to produce FAME. In our first paper (8), we described in situ esterification of high acidity RBO with methanol and ethanol using an acid catalyst, and ester yields depended on the RBO FFA content. Esterification with ethanol did not produce pure esters, as did methanol esterification. This was probably due to the higher solubility of oil components in ethanol than methanol and thus the greater amounts of nonreacted substrate. In a second study (9) we investigated in situ alcoholysis and extraction of soybean oil with methanol, ethanol, n-propanol, and butanol. Ethyl, propyl, and butyl esters of soybean FA could be obtained in high yields from in situ alcoholysis of soybean oil with these

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Section: Resultssupporting

confidence: 90%

Section: Methodsmentioning

confidence: 99%

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

Yücel

Türkay

2002

J Americ Oil Chem Soc

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“…Crude methyl esters were prepared by in situ esterification according to the method of Özgül and Türkay (3,5). Rice bran containing approximately 70% FFA was refluxed for 1 h with methanol and 5 mL of concentrated sulfuric acid as a catalyst.…”

Section: Methodsmentioning

confidence: 99%

“…If energy costs could be reduced by alternative technology, the importance of FAME would increase. For this reason we reported an in situ esterification method of rice bran oil that was more cost effective than the alternative methods (3)(4)(5).…”

mentioning

confidence: 97%

Purification of FAME by rice hull ash adsorption

Yücel

Türkay

2003

J Americ Oil Chem Soc

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Rice hull ash (RHA) and silica gel were used for purification of FAME by adsorption of FFA at atmospheric conditions. Studies demonstrated that silica gel is a better adsorbent than RHA in purifying FAME. However, both adsorbents were effective in reducing FFA levels from FAME extracts. The FFA adsorption efficiency increased with high FAME concentration and high adsorbent dosage. But FAME adsorption also increased with larger doses of adsorbent. The adsorption isotherms of FFA were determined with both adsorbents. FFA adsorption displayed Freundlich-type isotherms.Paper no. J10342 in JAOCS 80, 373-376 (April 2003). KEY WORDS:Adsorption, adsorption isotherms, competitive adsorption, fatty acid methyl ester, rice hull ash. FAME derived from vegetable oils and animal fats (biodiesel) have attracted considerable attention during recent years as an alternative to petroleum-based diesel fuel. Biodiesel has environmental advantages, relative to conventional diesel, as a renewable, biodegradable, and nontoxic fuel that does not require engine modification. FAME are produced by methanolysis of fats and oils with alcohols in the presence of an alkaline catalyst. Methyl esters are purified by distillation under vacuum and at high temperatures. The purity level of the diesel has a significant effect on its properties. Contaminating glycerides and FFA can cause serious combustion problems. Therefore, European Union biodiesel standards demand 99% purity (1). Seventy-eight percent of FAME production cost comes from refining the raw material (2). Cheaper raw materials and processing costs would affect profitability positively. If energy costs could be reduced by alternative technology, the importance of FAME would increase. For this reason we reported an in situ esterification method of rice bran oil that was more cost effective than the alternative methods (3-5).Rice hull ash (RHA), obtained by commercial combustion of rice hulls, has been used as a silica-based adsorbent to remove minor lipid components from vegetable oils (6-9). RHA was used to remove lutein, FFA, and phospholipids from soybean oil-hexane miscella (6-9). Proctor et al. (9) also showed that the adsorption of oleic acid onto RHA occurred by surface hydrogen bonding of the carboxylic acid and by the process of FFA adsorption, which followed Freundlich isotherms. Saleh and Adam (10) reported that lauric, myristic, and stearic acids adsorbed on RHA according to a Langmuir isotherm (10). Ooi and Lean found that rice ash could selectively adsorb MG in the presence of DG (11).The objectives of this study were (i) to demonstrate the removal of FFA from FAME by adsorption on RHA at room temperature, (ii) to determine the isotherm behavior of FFA adsorption onto RHA from FAME, and (iii) to compare RHA adsorption with that of commercial silica gel. MATERIALS AND METHODS Preparation of crude methyl esters.Crude methyl esters were prepared by in situ esterification according to the method of Özgül and Türkay (3,5). Rice bran containing approximately 70% FFA was refluxed...

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“…In-situ transesterifications, where the simultaneous extraction of neutral lipids and bran is produced, have also been proposed for soybean oil (Kildrian et al, 1996) and rice bran oil (Özgül and Türkay, 1993;Lai et al, 2005).…”

Section: Acid Transesterificationmentioning

confidence: 99%

Production of biodiesel from vegetable oils

Cerveró¹,

Coca²,

Luque³

2008

Grasas y Aceites

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RESUMEN Producción de biodiésel a partir de aceites vegetalesEl biodiésel se produce mediante la transesterificación de triglicéridos, presentes en grasas animales o aceites vegetales, en un proceso en el que un alcohol de bajo peso molecular desplaza a la glicerina. La mezcla de esteres así resultante posee unas propiedades físico-químicas similares a las del diésel procedente de petróleo. En este artículo se revisan las vías de síntesis de biodiésel mediante la transesterificación catalítica de aceites vegetales. Aunque actualmente a escala industrial solo se producen ésteres metí-licos, también se ha considerado el uso de etanol, ya que éste se obtiene también de fuentes renovables, generando así un combustible más limpio y biocompatible. PALABRAS-CLAVE: Biodiésel -Ésteres de ácidos grasos -Transesterificación -Triglicéridos. SUMMARY Production of biodiesel from vegetable oilsBiodiesel is produced by transesterification of triglycerides present in animal fat or vegetable oils, by displacing glycerine with a low molar mass alcohol. This resulting ester mixture has physico-chemical properties similar to those of petroleum diesel. This paper reviews the synthetic paths that lead to biodiesel by means of the catalytic transesterification of vegetable oils. Although methyl esters are at present the only ones produced at industrial scale, the use of ethanol, which can also be obtained from renewable resources, has been considered, since it would generate a cleaner and more biocompatible fuel.

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In situ esterification of rice bran oil with methanol and ethanol

Cited by 51 publications

References 4 publications

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

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

Purification of FAME by rice hull ash adsorption

Production of biodiesel from vegetable oils

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