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1.
Luis Vázquez Leslie Kleiner Casimir C. Akoh 《Journal of the American Oil Chemists' Society》2012,89(9):1655-1662
The concentration of stearidonic acid (SDA, 18:4 n-3) in free fatty acids (FFA) formed by selective esterification with dodecanol (lauryl alcohol) was studied. For this purpose, modified soybean oil (initial SDA content, ~23 %) was converted into its corresponding FFA by chemical hydrolysis. In a second step, the resulting FFA were esterified with dodecanol. Process variables such as the type of biocatalyst (lipase), substrate molar ratio and amount of lipase were evaluated. The best SDA concentration (58 %) and recovery (94 %) were attained by performing the esterification reaction for 4 h, with 1:1 molar ratio (dodecanol:FFA), and 5 % (w/w) Candida rugosa lipase as biocatalyst. It was observed that SDA was concentrated in the unesterified fraction. 相似文献
2.
Kyu-Wan Lee Cheng Hailan Jin Yinhua Young-Wun Kim Keun-Woo Chung 《Korean Journal of Chemical Engineering》2008,25(3):474-482
Vegetable oils are a major source of many base chemicals. Unfortunately, most vegetable oils exhibit lower thermal and oxidation
stability because of double bonds and even worse low-temperature behaviors. These physical and chemical properties can be
improved by various chemical modifications. The catalytic hydrogenation of soybean oil (SBO) over 25% Ni/SiO2 and 5% Pt/C is one of them, and the epoxidation of soybean oil and reduced soybean oil (RSBO) was carried out by using 30%
of hydrogen peroxide and acetic acid in the presence of conc. sulfuric acid, and/or acidic Amberlyst 15 resin catalyst. Various
alcohols and amines were added to the epoxidized soybean oil (ESBO) in the hope of improving lubricant properties. The reaction
products were carefully analyzed by means of 1H-NMR, FT-IR spectroscopies and GC-MS spectrometry. This paper covers the epoxidation of virgin and RSBOs, alcoholysis and
amidation of ESBO and SBO. Finally, the structures of cross linked products synthesized from ESBO and SBO with 1,6-hexamethylendiamine
were proposed. 相似文献
3.
Yomi Watanabe Toshihiro Nagao Yutaka Nishida Yoshiaki Takagi Yuji Shimada 《Journal of the American Oil Chemists' Society》2007,84(11):1015-1021
Acid oil, a by-product of vegetable oil refining, was enzymatically converted to fatty acid methyl esters (FAME). Acid oil
contained free fatty acids (FFA), acylglycerols, and lipophilic compounds. First, acylglycerols (11 wt%) were hydrolyzed at
30 °C by 20 units Candida rugosa lipase/g-mixture with 40 wt% water. The resulting oil layer containing 92 wt% FFA was used for the next reaction, methyl
esterification of FFA to FAME by immobilized Candida antarctica lipase. A mixture of 66 wt% oil layer and 34 wt% methanol (5 mol for FFA) were shaken at 30 °C with 1.0 wt% lipase. The degree
of esterification reached 96% after 24 h. The resulting reaction mixture was then dehydrated and subjected to the second esterification
that was conducted with 2.2 wt% methanol (5 mol for residual FFA) and 1.0 wt% immobilized lipase. The degree of esterification
of residual FFA reached 44%. The degree increased successfully to 72% (total degree of esterification 99%) by conducting the
reaction in the presence of 10 wt% glycerol, because water in the oil layer was attracted to the glycerol layer. Over 98%
of total esterification was maintained, even though the first and the second esterification reactions were repeated every
24 h for 40 days. The enzymatic process comprising hydrolysis and methyl esterification produced an oil containing 91 wt%
FAME, 1 wt% FFA, 1 wt% acylglycerols, and 7 wt% lipophilic compounds. 相似文献
4.
A. Ramírez Fajardo L. Esteban Cerdán A. Robles Medina M. M. Muñío Martínez E. Hita Peña E. Molina Grima 《Journal of the American Oil Chemists' Society》2006,83(3):215-221
The aim of this work was to increase the content of EPA in FFA extracts from a commercial oil (43.1% EPA) and from Phaeodactylum tricornutum oil, a single-cell oil, by selective enzymatic esterification. Initially, the FFA extract was esterified with lauryl alcohol
using nine lipases. All the lipases concentrated EPA in the unesterified FFA fraction. The criterion used to choose the best
lipase was maximization of the dimensionless effectiveness factor (FAE). This factor grouped the concentration factor (ratio between the EPA concentrations in the FFA fractions before and after
esterification) with EPA recovery in the final FFA fraction. Experiments were carried out to correlate FAE and the degree of esterification (ED, percentage of initial FA converted to lauryl esters). Lipase AK from Pseudomonas fluorescens was the most effective for concentrating EPA. Studies, of the optimal temperature, substrate molar ratio, solvent/substrate
ratio, and treatment intensity (product of the lipase mass and the reaction time) were also carried out using the lipase.
The maximum FAE was obtained when the ED was 60%: EPA concentration was 72%, and recovery was 73%. Finally, this lipase was used to concentrate
EPA from a FFA extract from P. tricornutum (23% EPA). The content of EPA in the unesterified FFA fraction increased to 71% at 78% ED (recovery of EPA, 75.5%). Comparison
of the results of obtained with the two FFA extracts seemed to indicate that the selectivity of Lipase AK for EPA depended
on the content of EPA, with higher contents of EPA in the initial FFA mixture reducing the selectivity for EPA. 相似文献
5.
The purification of tocopherols and phytosterols (referred to as sterols) from soybean oil deodorizer distillate (SODD) was
attempted. Tocopherols and sterols in the SODD were first recovered by short-path distillation, which was named sODD tocopherol/sterol
concentrate (SODDTSC). The SODD-TSC contained MAG, DAG, FFA, and unidentified hydrocarbons in addition to the two substances
of interest. It was then treated with Candida rugosa lipase to convert sterols to FA steryl esters, acylglycerols to FFA, and FFA to FAME. Methanol (MeOH), however, inhibited
esterification of the sterols. Hence, a two-step in situ reaction was conducted: SODDTSC was stirred with 20 wt% water and 200 U/g mixture of C. rugosa lipase at 30°C, and 2 moles of MeOH per mole of FFA was added to the reaction mixture after 16h. The lipase treatment for
40 h in total achieved 80% conversion of the initial sterols to FA steryl esters, complete hydrolysis of the acylglycerols,
and a 78% decrease in the initial FFA content by methyl esterification. Tocopherols did not change throughout the process.
To enhance the degree of steryl and methyl esterification, the reaction products, FA steryl esters and FAME, were removed
by short-path distillation, and the resulting fraction containing tocopherols, sterols, and FFA was treated with the lipase
again. Distillation of the reaction mixture purified tocopherols to 76.4% (recovery, 89.6%) and sterols to 97.2% as FA steryl
esters (recovery, 86.3%). 相似文献
6.
Methanolysis of rapeseed and soybean oil was studied using organic basic catalysts at boiling with reflux. The molar ratio methanol/free fatty acids (FFA) amounted to approx 2.8 : 1. The catalyst (guanidine carbonate) is used at concentrations between 0.5 and 1.3 wt‐% with respect to the oil. During boiling at reflux, guanidine carbonate disintegrates into guanidine and gaseous carbon dioxide. This is a very special reaction; other alcohols such as ethanol, propanol, etc. do not react in this way with guanidine carbonate. Under these conditions, the reaction mixture consists of two phases. The catalyst is mainly dissolved in the methanol phase. The rate of the phase transfer reaction is increased by stirring. With guanidine carbonate as a catalyst, neutralized rapeseed oil yielded, within 45 min and in one step, a product that meets the European Norm for biodiesel. Degummed and dried crude rapeseed oil contains ca. 1 wt‐% FFA, whereas crude degummed and dried soybean oil contains 0.3–0.7 wt‐% FFA. During catalysis with guanidine carbonate, the FFA are transformed into their methyl esters to about 60–70% at low concentrations in the crude oil (approximately up to 1–1.5%). Neutralization of the degummed and dried crude oil proved to be unnecessary in such cases. 相似文献
7.
8.
Acid oil is a by-product in the neutralization step of vegetable oil refining and is an alternative source of biodiesel fuel.
A model substrate of acid oil, which is composed of TAG and FFA, was used in experiments on the conversion to FAME by immobilized
Candida antarctica lipase. FFA in the mixture of TAG/FFA were efficiently esterified with methanol (MeOH), but the water generated by the esterification
significantly inhibited methanolysis of TAG. We thus attempted to convert a mixture of TAG/FFA to FAME by a two-step process
comprising methyl esterification of FFA and methanolysis of TAG by immobilized C. antarctica lipase. The first reaction was conducted at 30°C in a mixture of TAG/FFA (1∶1, wt/wt) and 10 wt% MeOH using 0.5 wt% immobilized
lipase, resulting in efficient esterification of FFA. The reaction mixture after 24 h was composed of 49.1 wt% TAG, 1.3 wt%
FFA, 49.1 wt% FAME, and negligible amounts of DAG and MAG (<0.5 wt%). The reaction mixture was then dehydrated and used as
a substrate for the second reaction, which was conducted at 30°C in a solution of the dehydrated mixture and 5.5 wt% MeOH
using 6 wt% immobilized lipase. The activity of the lipase increased gradually when the reaction was repeated by transferring
the enzyme to a fresh substrate mixture. The activity reached a maximum after 6 cycles, and the content of FAME achieved was
>98.5 wt% after a 24-h reaction. The immobilized lipase was very stable in the first-and second-step reactions and could be
used for >100 d without significant loss of activity. 相似文献
9.
10.
Facile purification of tocopherols from soybean oil deodorizer distillate in high yield using lipase 总被引:16,自引:0,他引:16
Yuji Shimada Seiichi Nakai Masaharu Suenaga Akio Sugihara Motohiro Kitano Yoshio Tominaga 《Journal of the American Oil Chemists' Society》2000,77(10):1009-1013
Tocopherols have been purified from deodorizer distillate produced in the final deodorization step of vegetable oil refining
by a process including molecular distillation. Deodorizer distillate contains mainly tocopherols, sterols, and free fatty
acids (FFA); the presence of sterols hinders tocopherol purification in good yield. We found that Candida rugosa lipase recognized sterols as substrates but not tocopherols, and that esterification of sterols with FFA could be effected
with negligible influence of water content. Enzymatic esterification of sterols with FFA was thus used as a step in tocopherol
purification. High boiling point substances including steryl esters were removed from soybean oil deodorizer distillate by
distillation, and the resulting distillate (soybean oil deodorizer distillate tocopherol concentrate; SODDTC) was used as
a starting material for tocopherol purification. Several factors affecting esterification of sterols were investigated, and
the reaction conditions were determined as follows: A mixture of SODDTC and water (4∶1, w/w) was stirred at 35°C for 24 h
with 200 U of Candida lipase per 1 g of the reaction mixture. Under these conditions, approximately 80% of sterols was esterified, but tocopherols
were not esterified. After the reaction, tocopherols and FFA were recovered as a distillate by molecular distillation of the
oil layer. To enhance further removal of the remaining sterols, the lipase-catalyzed reaction was repeated on the distillate
under the same reaction conditions. As a result, more than 95% of the sterols was esterified in total. The resulting reaction
mixture was fractionated to four distillates and one residue. The main distillate fraction contained 65 wt% tocopherols with
low contents of FFA and sterols. In addition, the residue fraction contained high-purity steryl esters. Because the process
presented in this study includes only organic solvent-free enzymatic reaction and molecular distillation, it is feasible as
a new industrial purification method of tocopherols.
This work was presented at the Biocatalysis symposium in April 2000, held at the 91st Annual Meeting and Expo of the American
Oil Chemists Society, San Diego, CA. 相似文献
11.
Cecilia Orellana‐Coca Samuel Camocho Dietlind Adlercreutz Bo Mattiasson Rajni Hatti‐Kaul 《European Journal of Lipid Science and Technology》2005,107(12):864-870
The effect of reaction parameters on lipase‐mediated chemo‐enzymatic epoxidation of linoleic acid was investigated. Hydrogen peroxide was found to have the most significant effect on the reaction rate and degree of epoxidation. Excess of hydrogen peroxide with respect to the amount of double bonds was necessary in order to yield total conversion within a short time period, as well as at temperatures above 50 °C to compensate for hydrogen peroxide decomposition. However, prolonged incubation with high excess of hydrogen peroxide leads to the accumulation of peracids in the final product. The reaction rate increased also with increasing hydrogen peroxide concentration (between 10 and 50 wt‐%); however, at the expense of enzyme inactivation. Linoleic acid was completely epoxidized when used at a concentration of 0.5–2 M in toluene at 30 °C, while in a solvent‐free medium, the reaction was not complete due to the formation of a solid or a highly viscous oily phase, creating mass transfer limitations. Increasing the temperature up to 60 °C also improved the rate of epoxide formation. 相似文献
12.
Nagao T Hirota Y Watanabe Y Kobayashi T Kishimoto N Fujita T Kitano M Shimada Y 《Lipids》2004,39(8):789-794
Tocopherols are purified industrially from soybean oil deodorizer distillate by a process comprising distillation and ethanol
fractionation. The waste material after ethanol fractionation (TC waste) contains 75% sterols, but a purification process
has not yet been developed. We thus attempted to purify sterols by a process including a lipase-catalyzed reaction. Candida rugosa lipase efficiently esterified sterols in TC waste with oleic acid (OA). After studying several factors affecting esterification,
the reaction conditions were determined as follows: ratio of TC waste/OA, 1∶2 (wt/wt); water content, 30%; amount of lipase,
120 U/g-reaction mixture; temperature, 40°C. Under these conditions, the degree of esterification reached 82.7% after 24 h.
FA steryl esters (steryl esters) in the oil layer were purified successfully by short-path distillation (purity, 94.9%; recovery,
73.1%). When sterols in TC waste were esterified with FFA originating from olive, soybean, rapeseed, safflower, sunflower,
and linseed oils, the FA compositions of the steryl esters differed somewhat from those of the original oils: The content
of saturated FA was lower and that of unsaturated FA was higher. The m.p. of the steryl esters synthesized (21.7–36.5°C) were
remarkably low compared with those of the steryl esters purified from high-b.p. soybean oil deodorizer distillate substances
(56.5°C; JAOCS 80, 341–346, 2003). The low-m.p. steryl esters were soluble in rapeseed oil even at a final concentration of 10%. 相似文献
13.
Separation of EPA and DHA in fish oil by lipase-catalyzed esterification with glycerol 总被引:4,自引:0,他引:4
The objective of this study was to investigate the use of lipases as catalysts for separating EPA and DHA in fish oil by kinetic
resolution based on their FA selectivity. Esterification of FFA from various types of fish oils with glycerol by immobilized
Rhizomucor miehei lipase under water-deficient, solvent-free conditions resulted in a highly efficient separation of EPA and DHA. Reactions
were conducted at 40°C with a 10% dosage of the lipase preparation under vacuum to remove the coproduced water, thus rapidly
shifting the reaction toward the products. The bulk of the FA, together with EPA, were converted into acylglycerols, whereas
DHA remained in the residual FFA. As an example, when FFA from tuna oil comprising 5% EPA and 25% DHA were esterified with
glycerol, 90% conversion into acylglycerols was obtained after 48 h. The residual FFA contained 78% DHA and only 3% EPA, in
79% DHA recovery. EPA recovery in the acylglycerol fraction was 91%. The type of fish oil and extent of conversion were highly
important parameters in controlling the degree of concentration. 相似文献
14.
Yuji Shimada Nobuhiro Fukushima Hiroyuki Fujita Yo Honda Akio Sugihara Yoshio Tominaga 《Journal of the American Oil Chemists' Society》1998,75(11):1581-1586
A 46% γ-linolenic acid (GLA)-containing oil was produced by selective hydrolysis of borage oil (GLA content, 22%) at 35°C
for 15 h in a mixture containing 50% water and 20 units (U)/g reaction mixture of Candida rugosa lipase. The GLA content was not raised over 46%, even though the hydrolysis extent was increased by extending the reaction
time and by using a larger amount of the lipase. However, 49% GLA-containing oil was produced by hydrolysis in a reaction
mixture with 90% water. This result suggested that free fatty acids (FFA) that accumulated in the mixture affected the apparent
fatty acid specificity of the lipase in the selective hydrolysis and interfered with the increase of the GLA content. To investigate
the kinetics of the selective hydrolysis in a mixture without FFA, glycerides containing 22, 35, and 46% GLA were hydrolyzed
with Candida lipase. The result showed that the hydrolysis rate decreased with increasing GLA content of glycerides, but that the release
rate of GLA did not change. Thus, it was found that the apparent fatty acid specificity of the lipase in the selective hydrolysis
was also affected by glyceride structure. When 46% GLA-containing oil was hydrolyzed at 35°C for 15 h in a mixture containing
50% water and 20 U/g of the lipase, GLA content in glycerides was raised to 54% at 20% hydrolysis. Furthermore, GLA content
in glycerides was raised to 59% when the hydrolysis extent reached 60% using 200 U/g of the lipase. These results showed that
repeated hydrolysis was effective to produce the higher concentration of GLA oil. Because film distillation was found to be
extremely effective for separating FFA and glycerides, large-scale hydrolysis of borage oil was attempted. As a result, 1.5
kg of 56% GLA-containing oil was obtained from 7 kg borage oil by repeated reaction. 相似文献
15.
化学-酶法催化烯烃环氧化是一种绿色环保的替代工艺,但是作为氧化剂的双氧水造成的脂肪酶失活和反应体系相间传质是亟待解决的难点问题。本文首先采用交联法成功合成了一种稳定的MOF固定化脂肪酶催化剂CALB@Uio-66-NH2,并用扫描电子显微镜(SEM)与X射线衍射仪(XRD)对其结构与晶型进行了表征。为了克服双氧水的相间传质障碍,考察了极性溶剂与酯类酰基供体对反应的影响,最终确定叔丁醇作为反应溶剂,乙酸乙酯作为酰基供体,构建了适用于柠檬烯化学-酶法环氧化的单相反应体系以取代传统的“有机-水”两相反应体系。通过对体系的催化剂添加量、过氧化氢与酰基供体浓度优化,获得了最佳的反应效率,在柠檬烯浓度为0.1mol/L时,催化剂最适添加量为20%、过氧化氢最适浓度为0.5mol/L、乙酸乙酯最适浓度为3mol/L,40℃下反应40min,柠檬烯-1,2-环氧化物收率可达到85.1%,而且在此条件下,CALB@Uio-66-NH2重用6次后仍能保持90.9%的相对活力。 相似文献
16.
Yuji Shimada Norihito Sakai Akio Sugihara Hiroyuki Fujita Yo Honda Yoshio Tominaga 《Journal of the American Oil Chemists' Society》1998,75(11):1539-1544
γ-Linolenic acid (GLA) is a physiologically valuable fatty acid, and is desired as a medicine, but a useful method available
for industrial purification has not been established. Thus, large-scale purification was attempted by a combination of enzymatic
reactions and distillation. An oil containing 45% GLA (GLA45 oil) produced by selective hydrolysis of borage oil was used
as a starting material. GLA45 oil was hydrolyzed at 35°C in a mixture containing 33% water and 250 U/g-reaction mixture of
Pseudomonas sp. lipase; 91.5% hydrolysis was attained after 24 h. Film distillation of the dehydrated reaction mixture separated free
fatty acids (FFA; acid value 199) with a recovery of 94.5%. The FFA were selectively esterified at 30°C for 16 h with two
molar equivalents of lauryl alcohol and 50 U/g of Rhizopus delemar lipase in a mixture containing 20% water. The esterification extent was 52%, and the GLA content in the FFA fraction was
raised to 89.5%. FFA and lauryl esters were not separated by film distillation, but the FFA-rich fraction contaminated with
18% lauryl esters was recovered by simple distillation. To further increase the GLA content, the FFA-rich fraction was selectively
esterified again under similar conditions. As a result, the GLA content in the FFA fraction was raised to 97.3% at 15.2% esterification.
After simple distillation of the reaction mixture, lauryl esters contaminating the FFA-rich fraction were completely eliminated
by urea adduct fractionation. When 10 kg of GLA45 oil was used as a starting material, 2.07 kg of FFA with 98.6% GLA was obtained
with a recovery of 49.4% of the initial content. 相似文献
17.
An enzymatic/acid-catalyzed hybrid process for biodiesel production from soybean oil 总被引:1,自引:0,他引:1
Wei-Jia Ting Chun-Ming Huang Nair Giridhar Wen-Teng Wu 《Journal of the Chinese Institute of Chemical Engineers》2008,39(3):203-210
The present study is aimed at developing an enzymatic/acid-catalyzed hybrid process for biodiesel production using soybean oil as feedstock. In the enzymatic hydrolysis, 88% of the oil taken initially was hydrolyzed by binary immobilized lipase after 5 h under optimal conditions. The hydrolysate was further used in acid-catalyzed esterification for biodiesel production and the effects of temperature, catalyst concentration, feedstock to methanol molar ratio, and reaction time on biodiesel conversion were investigated. By using a feedstock to methanol molar ratio of 1:15 and a sulfuric acid concentration of 2.5%, a biodiesel conversion of 99% was obtained after 12 h of reaction at 50 °C. The biodiesel produced by this process met the American Society for Testing and Materials (ASTM) standard. This hybrid process may open a way for biodiesel production using unrefined and used oil as feedstock. 相似文献
18.
以葵花籽油为原料,在冰醋酸和过氧化氢的共同作用下进行环氧化,制备葵花籽油基环氧化产物(SOEP);再以氢氧化锂为催化剂与二乙醇胺发生环氧开环反应,制备得到葵花籽油基多元醇(SOPOL)。探讨了反应温度和时间、冰醋酸/过氧化氢摩尔比对SOEP和SOPOL性能的影响,并采用核磁共振表征了SOEP和产物SOPOL的结构。结果表明,制备SOEP较为理想的反应温度为65℃,反应时间为10 h,葵花籽油(以双键计)、冰醋酸与过氧化氢的摩尔比为1∶2∶4;在135℃进行环氧基开环反应制备的SOPOL羟值可达到176 mgKOH/g,平均官能度为4.2。该SOPOL可替代传统石油基多元醇合成生物基聚氨酯树脂。 相似文献
19.
In this study a new value-added product was developed from soybean oil for use as a chemical feedstock. The investigation
and optimization of this work resulted in a fast and simple process to maleate soybean oil. An anhydride functionality was
introduced into soybean oil through a free radical-initiated maleation. Two initiators were evaluated, 2,5-bis(tert-butylperoxy)2,5-dimethylhexane peroxide and di-tert-butyl peroxide. The effects of reaction time, initiator concentration, maleic anhydride concentration, and reaction temperature
were investigated. The maleated soybean oil was characterized using acid value, iodine value, and FTIR spectroscopy. The acid
value was directly related to the initial concentration of maleic anhydride, whereas the concentration and type of initiator
had little effect on the acid value. The peroxide-initated functionalization of soybean oil with maleic anhydride in a closed
vessel at elevated pressure and temperature was found to proceed by a Diels-Alder mechanism. 相似文献
20.
Grigor B. Bantchev Bryan R. Moser Rex E. Murray Girma Biresaw Stephen R. Hughes 《Journal of the American Oil Chemists' Society》2016,93(12):1671-1682
Phosphonates were synthesized on a medium scale (~200 g) from three lipids—methyl linoleate (MeLin), high‐oleic sunflower oil (HOSO) and soybean oil (SBO), and three dialkyl phosphites—methyl, ethyl and n‐butyl, using a radical initiator. A staged addition of the lipid and the initiator was used to achieve good yields. Good results were observed with MeLin (94–99% conversions of the double bonds, as determined by NMR, and 83–99% isolated yields) and HOSO (99–100% NMR conversions, 87–96% isolated yields) using tert‐butyl perbenzoate as the initiator. With SBO, benzoyl peroxide was used as the initiator, due to its capability to generate radicals at a higher rate at slightly lower temperatures, and thus to shorten the reaction time. Conversions of 91–93% (by NMR) and isolated yields of 80–94% were achieved. The progress of the reaction was monitored with GC–MS. The products were characterized using 1H, 13C and 31P NMR, IR and gel permeation chromatography. A prolonged reaction led to some transesterification between the carboxylic and phosphite ester groups. Conditions favoring higher reaction rates led to the formation of more oligomers and benzoate fatty ester byproducts. The benzoate fatty ester byproducts were formed by the attack of a benzoate radical on a double bond. The more double bonds that were present per lipid molecule, the more oligomers were formed: MeLin 2–8%, HOSO 3–9% and SBO 8–29%. 相似文献