酸化油固定床酶法合成生物柴油研究

酸化油是油脂工作中以皂脚、油脚经酸化处理得到的产品.它的主要成份是游离脂肪酸及中性油,是生产脂肪酸的重要原料,但生产过程中有水解废水的产生,若将其直接排放,既污染了环境又浪费了资源.     

Study of immobilized candida rugosa lipase for biodiesel fuel production from palm oil by flow microcalorimetry

Enzymatic transesterification of palm oil with methanol and ethanol was studied. Of the four lipases that were tested in the initial screening, lipase Candida Rugosa (CR) resulted in the highest yield of mono alkyl esters. Lipase CR was further investigated in immobilized form within an activated carbon as support. The activated carbon was prepared by activation physical. Using the immobilized lipase CR, the effects of water and alcohol concentration, enzyme loading and enzyme thermal stability in the transesterification reaction were investigated. The optimal conditions for processing 50 g of palm oil were: 37 °C, 1:14.5 oil/methanol molar ratio, 1.0 g water and 500 mg lipase for the reactions with methanol, 35 °C, 1:15.0 oil/ethanol molar ratio, 1.0 g water, 500 mg lipase for the reactions with ethanol, and 35 °C, 1:10.0 oil/n-butanol molar ratio, 1.0 g water, 500 mg lipase for the reactions with ethanol. Subject to the optimal conditions, methyl and ethyl esters formation of 70 and 85 mol% in 1 h of reaction were obtained for the immobilized enzyme reactions. The flow microcalorimetry is an important and novel techniques is used in evaluation of biodiesel production.     

Biodiesel production and comparison using commercial lipase and chemical catalyst from Cassia auriculata oil

In this present investigation, Cassia auriculata was explored as a feedstock for production of biodiesel. Transesterification reaction was performed by both enzyme (lipase) and chemical (potassium hydroxide) catalyst with diverse acyl acceptors such as methanol, ethanol, propanol, n-propanol, butanol, n- butanol, and finally their biodiesel yield were also recorded. Process optimization was performed by both one factor at a time method and response surface method. The maximal biodiesel yield of 92% (weight/weight) was obtained at the following optimal conditions: Oil:Methanol molar ratio of 1:6 (moles/moles), the lipase concentration of 2% (weight/weight), at 35 ?°C and 120 ?min. The highest biodiesel yield from Cassia auriculata oil was occurred with excess methanol that aids the equilibrium shift in the forward direction. The kinetics of the transesterification reaction was investigated under optimal conditions and the activation energy was found to be 14.91 ?kJ/mol. Simultaneously Gas Chromatography – Mass Spectroscopy was also carried out for the biodiesel produced from Cassia auriculata and the same has been reported. The GC analysis declares the existence of fatty acid esters like hexadecanoic acid methyl ester, methyl stearate and the peak with retention time 12.8 ?min signifies the evidence of hexadecanoic acid methyl ester with 28% of yield content. This investigation also evaluated the biodiesel quality produced from lipase-transesterified Cassia auriculata oil based on fuel properties. Biodiesel properties Flash Point (FC), Pour Point (PP) and kinematic viscosity were compared with American (ASTM 6751) and European (EN 14214) Standards. Cassia auriculata oil had PP 6.7 ?°C and Kinematic viscosity (813 ?kg/m³) that agreed with both the standards. Thus this study showed that Cassia auriculata oil could be a better fuel alternative with further improvement of fuel properties.     

Optimization of biodiesel production via transesterification of soybean oil using α-MoO3 catalyst obtained by the combustion method

A catalyst based on MoO₃ was synthesized by a simple and fast pilot-scale combustion reaction method and applied to the conversion of soybean oil to biodiesel via transesterification. For that, the statistical analysis of the catalyst amount and temperature, factors that influence the process, was evaluated by means of central composite design 2². MoO₃ was characterized in terms of structure by X-ray diffraction (XRD), textural characterization Brunauer-Emmett-Teller (BET), density by helium pycnometry (DE), particle size analysis (DG) and acidity tests by temperature-programmed desorption of ammonia (NH₃-TPD), chemical analysis by X-ray fluorescence (EDX), morphology by scanning electron microscopy (SEM) and catalytic properties. The transesterification products were characterized by gas chromatography (GC), acidity index (AI) and kinematic viscosity (KV). The results indicate the catalyst formation with a surface area of 1.36 m²g^?1, and density of 4.5 g/cm³ which consists of a single crystalline phase of orthorhombic configuration, with total NH₃ acidity of 33.61 μ.mol/g. Morphological characterization revealed that the catalyst is formed by irregular plates of various sizes and shapes, with a wide sizes range of agglomerated particles. In the soybean oil transesterification reactions, the catalyst was active showing 96.9% conversion to ethyl esters. The experimental design was meaningful and predictive, with a reliability level of 95%. The statistical analysis identified temperature as a significant variable for the adopted planning. To conclude, a new single-phase catalyst (α-MoO₃) has been developed and successfully applied to the biodiesel Synthesis from soybean oil. These results have a positive and promising impact for biodiesel production by transesterification of soybean oil against ethanol.     

Optimization of alkaline transesterification of soybean oil and castor oil for biodiesel production

This article reports experimental data on the production of fatty acid ethyl esters from refined and degummed soybean oil and castor oil using NaOH as catalyst. The variables investigated were temperature (30–70°C), reaction time (1–3 h), catalyst concentration (0.5–1.5 w/wt%), and oil-to-ethanol molar ratio (1:3–1:9). The effects of process variables on the reaction conversion as well as the optimum experimental conditions are presented. The results show that conversions >95% were achieved for all systems investigated. In general, an increase in reaction temperature, reaction time, and in oil-to-ethanol molar ratio led to an enhancement in reaction conversion, whereas an opposite trend was verified with respect to catalyst concentration.     

Enantioselective transesterification catalysis by Candida antarctica lipase immobilized on superparamagnetic nanoparticles

Lipase B from Candida antarctica can be directly immobilized onto functionalized superparamagnetic nanoparticles, preserving its enzymatic activity in the enantioselective transesterification of secondary alcohols, with excellent results in terms of enantiomeric discrimination. The immobilized enzyme can be easily recovered with a magnet, allowing its reuse with negligible loss of activity.     

Production of biodiesel fuel by transesterification of rapeseed oil

Fatty acid methyl esters (FAMEs) show large potential applications as diesel substitutes, also known as biodiesel fuel. Biodiesel fuel as renewable energy is an alternative that can reduce energy dependence on petroleum as well as air pollution. Several processes for the production of biodiesel fuel have been developed. Transesterification processes under alkali catalysis with short-chain alcohols give high yields of methyl esters in short reaction times. We investigated transesterification of rapeseed oil to produce the FAMEs. Experimental reaction conditions were molar ratio of oil to alcohol, concentration of catalyst, type of catalyst, reaction time, and temperature. The conversion ratio of rapeseed oil was enhanced by the alcohol:oil mixing ratio and the reaction temperature.     

Esterification and transesterification with immobilized lipase in organic solvent

In this paper, we report the reactions of esterification and transesterification catalyzed by the following lipase adducts in organic solvents: (1) glass-adsorbed; (2) acetone precipitated on porous glass, kieselghur-adsorbed; (3) Al₂O₃-adsorbed; and (4) agar bead-adsorbed. The optimal water content varied for different forms of the enzymes. Under the most favorable conditions, kieselguhr-adsorbed and agar bead-adsorbed lipases, which have higher catalytic activities in organic solvents, are the best of all forms of lipases.     

Choline derivatives immobilized on silica to catalyze transesterification reaction for production of glycerophosphocholine

Choline derivatives were covalently immobilized on the surface of γ -aminated silica. The obtained immobilized choline derivative was then successfully used for a transesterification reaction to produce glycerophosphocholine (GPC). Fourier transform infrared analysis and thermogravimetric analysis/differential thermal gravimetry indicated that the surface of the γ -aminated silica was covered by choline derivatives and the highest immobilization amount reached 1.1 mmol/g under optimal conditions. More importantly, the highest yield of GPC reached 97.9% during transesterification. With regard to GPC in food or medicine for human use, the immobilization technology can avoid catalyst contamination of the product and increase the safety of the product. The recyclability and stability of the immobilized choline derivative were excellent, as demonstrated by its use 20 times without any loss of productivity. A first-order kinetic model was employed and the relevant parameters were calculated to investigate kinetic characteristics of transesterification.     

Biodiesel fuel from vegetable oil by various supercritical alcohols

Biodiesel was prepared in various supercritical alcohol treatments with methanol, ethanol, 1-propanol, 1-butanol, or 1-octanol to study transesterification of rapeseed oil and alkyl esterification of fatty acid at temperatures of 300 and 350°C. The results showed that in transes terification, the reactivity was greatly correlated to the alcohol: the longer the alkyl chain of alcohol, the longer the reaction treatment. In alkyl esterification of fatty acids, the conversion did not depend on the alcohol type because they had a similar reactivity. Therefore, the selection of alcohol in biodiesel production should be based on consideration of its performance of properties and economics.     

Biodiesel from soybean oil,castor oil and their blends

Even not being described in the EN 14112 standard, PDSC has been used for the determination of the biodiesel oxidative stability, by OIT and OT measurements. In this study, biodiesel blends were obtained by mixing soybean (BES) and castor (BEM) ethyl esters and its induction periods were measured by Rancimat and PDSC. The blends (BSM _X ) showed intermediate values of OSI, OT, and OIT, compared with BES and BEM. Although, the molar fraction of the components varied linearly in BSM _X , OSI, OT, and OIT values increased exponentially in relation to the castor biodiesel amount in the blends. Introduction of castor oil biodiesel increased the blend stability, so the BSM₃₀ blend reached the OSI limit of 6 h. OSI, OIT, and OT showed a high-linear correlation, pointing out that PDSC can be used in the analysis of this kind of biodiesel, with a smaller sample and analysis time, as compared to Rancimat. The use of biodiesel blends was a good alternative in the correction of the oxidative stability of the final product without the need of antioxidant addition.     

Thermal characterization of hydrotalcite used in the transesterification of soybean oil

Hydrotalcite was synthesised by co-precipitation method, calcined and characterized by XRD, BET, IR and TG/DTA/DTG analyses and tested as solid base catalyst in the transesterification of soybean oil with methanol, achieving a methyl ester content of 99.5%. The thermal decomposition of hydrotalcite calcined occurred in four mass loss steps at 28, 105, 203 and 400 °C. The hydrotalcite was recovered and through a simple evaluation by TG/DTA/DTG techniques it was found that at 500 °C is the temperature, where the organic matter should be eliminated from the catalyst. This study shows the importance of thermal analysis in the evaluation of the recovery temperature of hydrotalcite.     

Diphenylammonium salt catalysts for microwave assisted triglyceride transesterification of corn and soybean oil for biodiesel production

Diphenylammonium salts as catalysts for triglyceride transesterification have been investigated. Catalysts studied, such as diphenylammonium mesylate, were able to catalyze the transesterification process. Open atmosphere reactions and microwave-assisted reactions are considered and compared. Additionally, the study helps substantiate the advantage of microwave-assisted technology in organic synthesis.     

HPLC method for rapidly following biodiesel fuel transesterification reaction progress using a core-shell column

There are a wide and growing variety of feedstocks for biodiesel fuel. Most commonly, these feedstocks contain triglycerides which are transesterified into the fatty acid alkyl esters (FAAEs) which comprise biodiesel fuel. While the tranesterification reaction itself is simple, monitoring the reaction progress and reaction products is not. Gas chromatography-mass spectrometry is useful for assessing the FAAE products, but does not directly address either the tri-, di-, or monoglycerides present from incomplete transesterification or the free fatty acids which may also be present. Analysis of the biodiesel reaction mixture is complicated by the solubility and physical property differences among the components of the tranesterification reaction mixture. In this contribution, we present a simple, rapid HPLC method which allows for monitoring all of the main components in a biodiesel fuel transesterification reaction, with specific emphasis on the ability to monitor the reaction as a function of time. The utilization of a relatively new, core-shell stationary phase for the HPLC column allows for efficient separation of peaks with short elution times, saving both time and solvent.     

Partial transesterification of sunflower oil with ethanol by a silica fiber reinforced aerogel encapsulated lipase

A commercial lyophilized lipase of Burkholderia cepacia, from Amano, was encapsulated in silica aerogels reinforced with silica quartz fiber felt. This biocatalyst was applied in the direct transesterification of sunflower seed oil with ethanol, without any other solvent. When the molar ratio of ethanol to oil was two or three, the oil transformation kinetics was found to be very slow after the formation of 1 mole of fatty ethyl ester per mole of initial triglyceride. For a molar proportion of ethanol to oil ≈1, the recycling activity also decreased gradually in successive tests to reach an activity ≈7% of the initial activity, during the 5th test. Textural and structural analysis of the aerogels before and after catalytic tests showed that this deterioration was associated with a modification of the aerogel, by preferential adsorption of glycerol or possibly other transesterification products such as diglycerides. Besides, it is proposed that one of the cause for the aerogel loss of activity at an initial molar ratio of ethanol:oil of 3:1 was due to a progressive inhibition of the enzyme by excess adsorbed ethanol. The aerogel samples were also compared to a commercial product of lipase immobilized on polymer beads, from Fluka. The silica aerogels somewhat improved, to a limited extent, the activity during recycling.     

锂-铝类水滑石催化大豆油酯交换制备生物柴油

采用共沉淀法制备了不同锂-铝比[n(Li)/n(Al)]的Li-Al类水滑石,经不同温度下焙烧得到复合氧化物;将复合氧化物作为大豆油与甲醇反应制备生物柴油的催化剂,考察了其对大豆油酯交换反应的催化性能.结果表明,n(Li)/n(Al)=13的类水滑石在400℃下焙烧得到的复合氧化物对大豆油酯交换反应具有极高的催化活性....     

Process development for production of medium chain triglycerides using immobilized lipase in a solvent-free system

The synthesis of tricaprylin, tricaprin, trilaurin, and trimyristin in a solvent-free system was conducted by mixing a commercial immobilized lipase with the organic reagents (glycerol and fatty acid) in a 20-mL batch reactor with constant stirring. The effects of temperature, fatty acid/glycerol molar ratio, and enzyme concentration on the reaction conversion were determined. The reactions were carried out for 26 h and the nonpolar phase was analyzed by gas chromatography. Appreciable levels of medium chain triglycerides were achieved, except for tricaprylin. The higher selectivity values for the production of triglycerides were attained under the following conditions: a fatty acid/glycerol molar ratio of 5; enzyme concentration of 5 or 9% (w/w); and temperatures of 70°C (tricaprin), 80°C (trilaurin), and 90°C (trimyristin). After completion of the esterification reaction under these conditions, the recovery of the triglyceride and fatty acids, and the reusability of the enzyme were studied. The unreacted fatty acid and the produced triglyceride were satisfactorily recovered. The commercial immobilized lipase was used in 10 consecutive batch reactions at 80°C, with 100% selectivity in the trilaurin and trimyristin synthesis. The possibility of enzyme reuse and the recovery of residual fatty acid are relevant results that contribute to increasing the viability of the process.     

Biodiesel from rapeseed oil of turkish origin as an alternative fuel

The crude rapeseed oil was transesterified using methanol and using sodium hydroxide as a catalyst, and the varieties affecting the monoester yield were investigated. The methyl ester fuel called Biodiesel, produced under the determined optimum reaction conditions, was tested according to the standard methods for its fuel properties. Biodiesel fuel properties were found to be very close to those of Grade No. 2-D diesel fuel.