Microwave-assisted solvent extraction of castor oil from castor seeds

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.     

Ceramer coatings from castor oil or epoxidized castor oil and tetraethoxysilane

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.     

Physical-chemical properties of waste cooking oil biodiesel and castor oil biodiesel blends

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.     

A rapid method for evaluation of the oxidation stability of castor oil FAME: influence of antioxidant type and concentration

The oxidation stability of castor oil fatty methyl ester (FAME), doped with four different phenolic antioxidants, was evaluated using a rapid method of thermal and air-contact degradation. The methodology is based on the induction times observed when the samples are contacted with pure oxygen at elevated pressures and temperatures. The results indicate different performances of the antioxidants as well as synergisms between antioxidants and biodiesel. In general, the addition of antioxidants increased from 6-15 times the stability of castor oil FAME., with BHA (butylated hydroxyanisol) showing the best results for improving antioxidation in castor oil biodiesel.     

A process for solid fat from castor oil by simultaneous hydrogénation and dehydration

A single step process has been developed on a pilot plant scale (15 kg/batch) for simultaneous hydrogenation and dehydration of castor oil using nickel catalyst and attapulgite to yield solid fats having a hydroxyl value of 7–33 and an iodine value of 41–56. The polymer and keto fatty acid contents in the products were up to 2% and 3.2%, respectively. The product can be used in the manufacture of soap as the hard fat component and in textile sizing.     

Preparation and properties of urethane alkyd based on a castor oil/jatropha oil mixture

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.     

Reaction rates of simultaneous dehydration and hydrogenation of castor oil

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.     

Transesterification of castor oil assisted by microwave irradiation

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.     

One-pot synthesis of (E)-2-nonenal from castor oil

A one-step procedure for the preparation of (E)-2-nonenal from commercial castor oil by ozonolysis in acetic acid, followed by exposure of the resulting intermediate product top-toluene sulfonic acid, is described. The manufactured aldehyde is of high purity and the method, by virtue of being simple and using inexpensive raw material, has advantages over those reported in the literature.     

The kinetics of the esterification reaction between castor oil and oleic acid

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.     

Production of conjugated linoleic acid isomers by dehydration and isomerization of castor bean oil

The possibility of combining dehydration and isomerization of castor bean oil as a means to obtain CLA as TAG forms was studied. First, dehydration was carried out using various catalysts and reaction parameters. Best results were obtained using phosphoric acid (0.1% w/w) at 280°C for 5 h. Under such conditions, satisfactory proportions of CLA were obtained (54% of total FA) with a majority of 9-cis, 11-trans isomer (61% of total CLA). Other catalysts such as bisulfate-bisulfite, sulfuric acid, tungstic and phosphotungstic acids, or resins and zeolites were also tested. With the exception of resins and zeolites, these catalysts also led to CLA production but in limited amounts in comparison with phosphoric acid. In a second step, an isomerization reaction was carried out to transform the residual nonconjugated linoleic acid also produced during dehydration into CLA. Using Wilkinson catalyst [RhCl(PPh₃)₃] in ethanol solvent, dehydrated castor bean oil was isomerized in high yields (>98%), allowing a complete disappearance of nonconjugated linoleic acids. The resulting dehydrated/isomerized oil contained more than 87% CLA with the 9-cis, 11-trans isomer being predominant (40% of CLA fraction). Finally, urea fractionation was also applied on dehydrated/isomerized castor bean oil FA to obtain FFA products containing about 93% CLA.     

Transesterification of castor oil: Effect of the acid value and neutralization of the oil with glycerol

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.     

Cinnamoyl esters of lesquerella and castor oil: Novel sunscreen active ingredients

Lesquerella and castor oils were esterified with cinnamic acid (CA) and 4-methoxycinnamic acid (MCA). Esterification of the hydroxy oils reached 85% completion with CA and 50% conversion with MCA. The hydroxy oils were esterified at 200°C under a nitrogen atmosphere within a sealed system. Unreacted CA and MCA were removed from the reaction mixtures by sublimation at 100°C under vacuum. The resultant methoxycinnamic oils possessed a broader, more blue-shifted UV absorbance, 250 to 345 nm with a λ_max of 305 nm, compared with the cinnamic oils, which absorbed from 260 to 315 nm, λ_max of 270 nm. The methoxycinnamic oils provide better UV-B absorption and thus are better candidates to be used as sunscreen active ingredients. Esterifications of the hydroxy oils with MCA at 200°C resulted in conversion of 40% of the MCA to undesirable by-products. Esterifications with MCA performed at 175°C in the presence of a tin catalyst resulted in similar percent conversions to product without degradation of MCA. Esterifications of lesquerella oil with MCA at 175°C resulted in higher conversions, 43%, than analogous esterifications with castor oil, 29%. The hydroxyl groups of the lesquerella and castor oils provide their excellent emolliency, lubricity, and noncomedogenicity in skin and personal-care products. Therefore, reactions that convert only 50% of the available hydroxyl groups of the lesquerella oil to cinnamoyl-esters are preferred.     

The decomposition of secondary esters of castor oil with fatty acids

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.     

Continuous synthesis of castor oil ethyl esters under supercritical ethanol

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.     

PDMS改性蓖麻油基水性聚氨酯的制备及防污性能

本研究以低成本的二甲基二甲氧基硅烷为主要原料，通过水解缩合反应制备合成了聚二甲基硅氧烷（PDMS），进而将其引入蓖麻油基水性聚氨酯（CWPU-SOP）中制备了具有防污性能的蓖麻油基水性聚氨酯(PDMS/CWPU-SOP)。结果表明，当PDMS引入量为8%时，与CWPU-SOP薄膜相比，PDMS/CWPU-SOP薄膜接触角提高了25?，达110?，PDMS/CWPU-SOP薄膜的吸水率下降了7%，为15%；PDMS提高了薄膜疏水性和耐水性。PDMS/CWPU-SOP薄膜在不同酸碱性的液滴在其表面可自由滚落且不留痕迹，具有一定的防污性能。     

Comparison of soybean oil and castor oil methanolysis in the presence of tin(IV) complexes

In this paper we present and discuss the results obtained from the methanolysis of two vegetable oils with very distinct triglyceride composition, castor oil and soybean oil, using Lewis acid Sn(IV)-based compounds as catalysts. For all transesterification reactions, two different types of reactors were employed; an open glass (OG) reactor equipped with a reflux condenser, and a closed steel (CS) reactor. The results indicated that in all reactions assayed, regardless of the Sn(IV)-based catalyst employed, the yields obtained with the methanolysis of castor oil are generally lower than those carried out with soybean oil. Furthermore, independently of the oil used, the reaction yields tend to be higher when the CS reactor was employed.     

Further study on the one-pot synthesis of (E)-2-nonenal from castor oil

A one-step procedure is described for the synthesis of (E)-2-nonenal from commercial castor oil by ozonolysis in methanol, followed by reduction of the ozonide products with dimethyl sulfide and exposure of the resulting intermediate product to dilute sulfuric acid. The developed process allows the production of the aldehyde with a yield of 80% at a purity of 95%. The method has advantages over all those reported earlier, because of inexpensive raw material and reducing agent, recycling of the solvent and its unusual simplicity.     

A rapid quantitative method for determination of astaxanthin pigment concentration in oil extracts

Power models were developed to demonstrate relationships between absorption maxima (λmax) and specific extinction coefficients (E _1cm ^1% ) for the carotenoid astaxanthin and astacene in different oils and organic solvents. An accurate and rapid determination of concentration of astaxanthin-enriched oil can be achieved by using the predicted E _1cm ^1% value based on absorption maxima in the visible light spectrum. Several vegetable or fish oils have been shown to be comparatively efficient in extracting astaxanthin pigment from crustacean waste in a pilot plant.