共查询到20条相似文献,搜索用时 15 毫秒
1.
A. T. Erciyes L. Dandik O. S. Kabasakal 《Journal of the American Oil Chemists' Society》1991,68(9):639-641
In this study, esterification of castor oil with oleic acid was investigated in view of the reaction kinetics under various
conditions. Potassium hydroxide,p-toluenesulfonic acid and tin chloride (SnCl22H2O) were used as catalysts. Reaction was carried out at 200°C, 225°C and 250° C by using equivalent proportions of the reactants.
For tin chloride, experimental data fitted the second-order rate equation, while for the other catalysts the obtained data
fitted the third-order rate equation. 相似文献
2.
Terry A. Isbell Steven C. Cermak 《Journal of the American Oil Chemists' Society》2002,79(12):1227-1233
Triglyceride (TG) estolides were synthesized from the hydroxy moieties of lesquerella and castor oils with oleic acid. Complete
esterification of the hydroxy oils was possible when a slight excess of oleic acid was employed (1 to 1.5 mole equivalents).
The estolides could be formed in the absence of catalyst at 175 to 250°C under vacuum or a nitrogen atmosphere. The optimal
reaction conditions were found to be under vacuum at 200°C for 12 h for lesquerella and 24 h for castor oil. The lesquerella
esterification reaction was completed in half the time of the for castor and with lower equivalents of oleic acid due to the
difunctional hydroxy nature of lesquerella TG compared to the trifunctional nature of castor TG. Interesterification or dehydration
of the resulting estolides to conjugated FA was not a significant side reaction, with only a slight amount of dehydration
occurring at the highest temperature studied, 250°C. Use of a mineral-or Lewis-acid catalyst increased the rate of TG-estolide
formation at 75°C but resulted in the formation of a dark oil, and the reaction did not go to completion in 24 h. Estolide
numbers (i.e., degree of estolide formation) for the reaction and characterization of the products were made by 1H NMR and 13C NMR. The decrease in the hydroxy methine signal at 3.55 ppm was used to quantify the degree of esterification by comparing
this integral to the integral of the alpha methylene protons on the glycerine at 4.28 and 4.13 ppm. 相似文献
3.
Ignacio VieitezMaría J. Pardo Camila da Silva Cristiane BertoldiFernanda de Castilhos J. Vladimir OliveiraMaria A. Grompone Iván Jachmanián 《The Journal of Supercritical Fluids》2011,56(3):271-276
The transesterification of castor oil under supercritical ethanol using a catalyst-free continuous process was investigated. The effect of water concentration on the reaction medium, reaction temperature, pressure, and substrates flow rate were studied. A maximum ester content of 74.2% was achieved when the reactor was operated at 573 K, 20 MPa, substrates flow rate of 0.8 ml min−1, and 5 wt% water concentration in the alcohol. The ester content of the product increased with the operation temperature, but after certain temperature level the converse effect was observed. This adverse effect was attributed to oil degradation, which increased to 88.7% at 648 K (at the flow rate of 0.8 ml min−1). A favorable effect on ester content was observed when the water concentration was increased, unlike the effect of water on the conventional alkali-catalyzed process. 相似文献
4.
A. T. Erciyes L. Dandik F. S. Erkal 《Journal of the American Oil Chemists' Society》1991,68(9):642-645
In this study, thermal splitting of secondary fatty acid esters of castor oil was investigated to determine the reaction kinetics
under various conditions. Zinc oxide,p toluenesulfonic acid and sulfuric acid were used as catalysts. Reactions were carried out at 260, 270, and 280°C. Experimental
data fitted the first-order rate equation for the catalyzed and noncatalyzed reactions. In addition to the kinetic investigation,
the splitting (pyrolysis) mixture was evaluated in the preparation of a synthetic drying oil. For this purpose, the mixed
fatty acids of linseed, sunflower andEcballium elaterium seed oils were used in the esterification stage of the process. Pyrolysis mixtures were converted to drying oils by combining
the liberated acids with equivalent amounts of glycerol. The oils thus obtained show good drying oil properties. 相似文献
5.
This study concerns the preparation and evaluation of nonionic surfactants prepared from polyethylene glycol (PEG) esters of castor oil fatty acid, a source of hydroxy fatty acid. A lipase-catalyzed esterification reaction has been employed to prepare PEG esters of hydroxy acid to overcome problems associated with chemical processes. Castor oil fatty acid (85% ricinoleic acid) was mixed with PEG of different molecular weight. Rhizomucor miehei lipase was added as catalyst (10% level) and the reaction was continued at 60°C under 2 mm Hg pressure for 360 min. Conversion of PEG to esters was in the range of 86–94%, depending on the molecular size of PEG. The products were isolated and examined for surface activity by surface tension measurement. Surface tension values measured at 25°C were about 36–37 dynes/cm. 相似文献
6.
A. Erdem-Şenatalar E. Erencek A. T. Erciyes 《Journal of the American Oil Chemists' Society》1995,72(8):891-894
The apparent orders of the Lewis acid-catalyzed esterification reactions between castor oil and oleic acid are known to change
with the catalyst used and with the reaction temperature. A mechanism is proposed in this study to explain the variations
(with temperature) in the apparent orders of the cobalt chloride-catalyzed esterification reaction between castor oil and
oleic acid. According to the proposed mechanism, an acid-catalyst intermediate forms in an initial, fast quasi-equilibrium
step, and this intermediate then reacts with the oil to yield the products and to regenerate the catalyst in the rate-determining
second step. A general rate expression, with an acid concentration term and a temperature-dependent constant in the denominator,
is derived from the proposed mechanism and is verified with data obtained at different temperatures. 相似文献
7.
A. Erdem-Şenatalar E. Erencek M. Tüter A. T. Erciyes 《Journal of the American Oil Chemists' Society》1994,71(9):1035-1037
The effects of two Lewis acid catalysts, tin chloride and cobalt chloride, on the kinetics of the esterification reaction
between castor oil and oleic acid have been investigated. Uncatalyzed and catalyzed reactions were carried out both in the
presence of excess oil and with equivalent amounts of reactants at various temperatures. The reaction, with respect to castor
oil concentration, is first-order in all cases, whereas with acid concentration the reaction was observed to change from second-order
for the uncatalyzed reaction to first-order for tin chloride-catalyzed and to zero-order for cobalt chloride-catalyzed reactions.
The order (with respect to acid) also changed with temperature for the cobalt chloride-catalyzed reaction. 相似文献
8.
Effrat L. Fayer Emily Rosen Diana M. Cermak Steven C. Cermak 《Journal of the American Oil Chemists' Society》2023,100(10):803-813
Hydroxy fatty acids (HFAs) have long been a staple component of feedstock oils with uses ranging from motor oils to food to pharmaceuticals. Castor oil, which contains the HFA ricinoleic acid as its principal component, is the most widely used source of HFA in the world. In addition, bisphosphonates are a functional moiety that has been shown to display a variety of industrial applications, ranging from use in water softeners to osteoporosis drugs, primarily due to their affinity for the calcium ion. We have long been interested in the modification of ricinoleic acid from castor oil to phosphorus derivatives, including α-hydroxy phosphonates and phosphonic acids, and have now accomplished the synthesis of a family of ricinoleic-derived bisphosphonates: one that retains the cis alkene found in ricinoleic acid and one where the alkene has undergone hydrogenation. These compounds have been produced in high yields and high purity and the synthesis of these compounds is reported. 相似文献
9.
This study was aimed at evaluating the physicochemical properties and oxidation stability of castor oil using microwave-assisted solvent extraction (MAE). MAE was performed using 5% ethanol in hexane as solvent at different extraction times, power intensities and solvent-to-feed (S/F, ml of solvent to gram of feed) ratios. The process parameters were optimized by statistical approach using historical data design of response surface method (RSM). The oils were characterized for yield, physicochemical properties, dielectric properties and oxidation stability, and comparison was also made with oil extracted using Soxhlet method. Results show that the maximum oil yield of 37% was obtained at 20 min with microwave power intensity of 330 W and S/F ratio of 20. The main fatty acid composition of castor oil is ricinoleic acid. The density, refractive index, dielectric properties and oxidation stability of oils are not affected by the extraction methods and extraction parameters of MAE. However, the MAE-extracted oil is more viscous compared to that by Soxhlet method. With extra caution on oil oxidation, MAE could be a promising solvent extraction method with an 86% less in processing time and a higher yield. 相似文献
10.
Mangesh G. Kulkarni Sudhirprakash B. Sawant 《European Journal of Lipid Science and Technology》2003,105(5):214-218
Esters of castor oil and hydrogenated castor oil were prepared with C6, C12, C16, C18 fatty acids, using tetra‐n‐butyl titanate as a catalyst and n‐butyl benzene as a water entrainer. Physical properties such as melting point, refractive index, viscosity, and specific gravity of these esters were measured. Slip melting points of the esters were very low in both cases. These esters did not crystallize even at low temperature. The highest slip melting point obtained was 21 °C with stearoyl hydrogenated castor oil ester and lowest slip melting point obtained was —6 °C with hexanoyl castor oil ester. 相似文献
11.
Maria Augusta de Luca Márcia Martinelli Marly Maldaner Jacobi Patrícia Luíza Becker Marco Flores Ferrão 《Journal of the American Oil Chemists' Society》2006,83(2):147-151
New inorganic-organic hybrids were synthesized through the reaction of castor oil (CO) or epoxidized castor oil (ECO) with
tetraethoxysilane (TEOS). The mass proportions of ECO/TEOS varied from 90∶10 to 60∶40, and films of the material were thermally
cured. An IR spectroscopy analysis was performed, and macro- and microscopic properties such as adhesion, hardness, swelling
in toluene, microstructure (scanning electron microscopy), and T
g
were investigated as a function of the proportion of their inorganic-organic precursor. Morphologic studies showed that the
hybrid films were homogeneous when lower proportions of the inorganic precursors were used. Hardness and tensile strength
increased with TEOS concentration, whereas swelling in toluene decreased with TEOS concentration. Good adhesion was observed
throughout the hybrid series. 相似文献
12.
13.
Osmano Souza Valente Vanya Márcia Duarte Pasa Carlos Rodrigues Pereira Belchior José Ricardo Sodré 《Fuel》2011,90(4):1700-1702
This work presents the physical-chemical properties of fuel blends of waste cooking oil biodiesel or castor oil biodiesel with diesel oil. The properties evaluated were fuel density, kinematic viscosity, cetane index, distillation temperatures, and sulfur content, measured according to standard test methods. The results were analyzed based on present specifications for biodiesel fuel in Brazil, Europe, and USA. Fuel density and viscosity were increased with increasing biodiesel concentration, while fuel sulfur content was reduced. Cetane index is decreased with high biodiesel content in diesel oil. The biodiesel blends distillation temperatures T10 and T50 are higher than those of diesel oil, while the distillation temperature T90 is lower. A brief discussion on the possible effects of fuel property variation with biodiesel concentration on engine performance and exhaust emissions is presented. The maximum biodiesel concentration in diesel oil that meets the required characteristics for internal combustion engine application is evaluated, based on the results obtained. 相似文献
14.
Douglas G. Hayes Kenneth D. Carlson Robert Kleiman 《Journal of the American Oil Chemists' Society》1996,73(9):1113-1119
The lipolysate from immobilizedRhizomucor miehei lipase (Lipozyme
tm
)-catalyzed hydrolysis of lesquerella oil contains typically 35% free fatty acid (FFA), 2% monoglyceride, 25% diglyceride
(DG), and 38% triglyceride (TG). Of the FFA, 75–80% are hydroxy acids (HFA). Various methods for isolating HFA from the lipolysate
were examined, and a novel saponification/extraction method was developed. Lipolysate was mixed with 4 vol equivalents each
of KOH/phosphate buffer and polar organic solvent. Hexane was then added to enhance phase separation. Three phases formed:
a lower aqueous phase containing nothing of interest, a polar organic solvent middle phase that contained mostly fatty acid
soaps, and a hexane-rich upper phase that contained mostly DG and TG, which can be recycled to a relipolysis step. The middle
phase, when treated with concentrated hydrochloric acid, NaCl-saturated water, and hexane, released the FFA into the hexane.
This fraction, referred to as the “Product” contained >99% of the FFA released in the lipolysis. “Product” consisted of 85–90%
FFA, of which 75–80% was HFA. The other 10–15% of the “Product” consisted of partial glycerides and TG. The most critical
parameters for the extraction are the pH of the aqueous solution and the polarity of the organic solvent (acetone was found
to be the best choice). Additional purification steps for the “Product” are discussed. 相似文献
15.
Castor oil is the only major natural vegetable oil that contains a hydroxyl group and so it is widely used in many chemical industries, especially in the production of polyurethanes. In this work, castor oil was interesterified with jatropha oil and the product was subsequently reacted with toluene diisocyanate to obtain urethane alkyd. The prepared urethane alkyd was characterized and its properties were determined and compared with those of the conventional (glycerol/jatropha oil) and commercial urethane alkyds. The castor oil/jatropha oil-based urethane alkyd had a lower molecular weight and viscosity, a slightly lower hardness and greatly longer drying time than the conventional and commercial urethane alkyds, but otherwise the film properties were broadly similar, including being very flexible, with an excellent adhesion and high impact resistance. In addition, they also exhibited excellent resistance to water and acid. 相似文献
16.
B. Vishwanadham A. A. Khan M. Bhagvanth Rao 《Journal of the American Oil Chemists' Society》1995,72(9):1033-1036
The reaction rates of simultaneous dehydration and hydrogenation of castor oil to make tallow-like hard fat were calculated
through a simplified procedure which makes use of a new variable derived from the incremental change in hydrodxyl value and
iodine value. 相似文献
17.
Louise L. Sousa 《Fuel Processing Technology》2010,91(2):194-196
This paper evaluates the production of methyl esters from castor oil and methanol after neutralization of castor oil with glycerol. The reaction was carried out under atmospheric pressure and ambient temperature in a batch reactor, employing potassium hydroxide as catalyst. Results showed high yield of castor oil into methyl esters after neutralization of castor oil with glycerol. The highest yield observed was of 92.5% after 15 min of reaction. The best operating condition was obtained applying an alcohol to oil molar ratio of 6.0 and 0.5% w/w of catalyst. 相似文献
18.
S. Babu R. V. Sudershan R. K. Sharma Ramesh V. Bhat 《Journal of the American Oil Chemists' Society》1996,73(3):397-398
A simple and rapid polarimetric method is developed for quantitation of adulteration of castor oil in edible oils such as
cottonseed, coconut, mustard, olive, palm, peanut, rice bran, safflower, soybean, and sunflower. The method is based on the
optical activity of ricinoleic acid (12-hydroxy octadecenoic acid), a major constituent of castor oil. There is a good correlation
between optical rotation and castor oil content in admixtures above 5%. Highly colored and viscous oils interfere in the measurement
of optical activity. The method is highly specific and cost-effective. No solvents and chemicals are required for the analysis
because no sample processing is involved in the present method. 相似文献
19.
Microwave assisted transesterification of castor bean oil was carried out in the presence of methanol or ethanol, using a molar ratio alcohol/castor bean oil of 6:1, and 10% w/w of acidic silica gel or basic alumina (in relation to the oil mass) as catalyst. Under acid catalysis, the reaction occurred with satisfactory yields using H2SO4 immobilized in SiO2, methanol under conventional conditions (60 °C for 3 h) as well as using microwave irradiation for 30 min. The best results were obtained under basic conditions (Al2O3/50% KOH) using methanol and conventional (60 °C, stirring, 1 h) or microwave conditions (5 min). In comparison with conventional heating, the catalyzed alcoholysis assisted by microwaves is much faster and leads to higher yields of the desired fatty esters. 相似文献
20.
The aim of this work was the synthesis of polyester polyols from renewable sources as one of the important compounds of polymeric polyurethane (PU) adhesives. The polyester polyols were synthesized by condensation polymerization of different dicarboxylic acids with castor oil and the reaction conditions were in agreement with green chemistry principles. The preparation of PU wood adhesives was carried out by the reaction of each obtained polyester polyol with 4, 4′-diphenylmethane diisocyanate (MDI). The adhesive performance was improved by mixing the obtained polyester polyols with polypropylene glycol (PPG 400) and butanediol (BD). Different NCO/OH ratios were used to obtain adhesives with appropriate properties. The structures of the synthesized polyesters and adhesives were characterized by FTIR, thermogravimetric analysis (TGA) and lap shear strength values were also determined in various conditions such as cold water, hot water, acid and alkali solutions. 相似文献