Refined soybean oil transesterification enhanced by sonication

Biofuels are of great topical interest, especially in the light of recent European directives. Biodiesel is both already available and thoroughly regulated. A critical aspect of the transesterification process, used in biodiesel production, is maximization of the contact surface between reagents. This is currently achieved using discontinuous processes with mechanical agitation, which however afford poor mixing efficiency. Ultrasound appears to be an effective method to enhance mixing intensity. The aim of this work was to assess the advantages offered by this technique, especially in terms of process velocity. For this purpose a small scale experimental apparatus for biodiesel production integrated with a modular ultrasound system was set up. Plant dimension and energy inputs were chosen to enable eventual industrial implementation. Plant performances were assessed as the velocity of oil conversion to fatty acids methyl esters. The product was analyzed according to EN 14105. In general, the efficiency of ultrasound in increasing reaction velocity was markedly affected by residual triglyceride content. Conversion rates in line with EN 14214 and ASTM D6751 standard specifications, which allow a maximum residual triglycerides content of 0.20%, were obtained with reductions in reaction time of about 20%. In less stringent conversion conditions, e.g. 3% triglycerides, the reaction time was roughly halved. Below 1% of triglycerides residues sonication should be interrupted and the process continued with conventional agitation.     

Artificial Neural Network based prediction of performance and emission characteristics of a variable compression ratio CI engine using WCO as a biodiesel at different injection timings

Due to the increasing demand for fossil fuels and environmental threat due to pollution a number renewable sources of energy have been studied worldwide. In the present investigation influence of injection timing on the performance and emissions of a single cylinder, four stroke stationary, variable compression ratio, diesel engine was studied using waste cooking oil (WCO) as the biodiesel blended with diesel. The tests were performed at three different injection timings (24°, 27°, 30° CA BTDC) by changing the thickness of the advance shim. The experimental results showed that brake thermal efficiency for the advanced as well as the retarded injection timing was lesser than that for the normal injection timing (27° BTDC) for all sets of compression ratios. Smoke, un-burnt hydrocarbon (UBHC) emissions were reduced for advanced injection timings where as NO_x emissions increased. Artificial Neural Networks (ANN) was used to predict the engine performance and emission characteristics of the engine. Separate models were developed for performance parameters as well as emission characteristics. To train the network, compression ratio, injection timing, blend percentage, percentage load, were used as the input parameters where as engine performance parameters like brake thermal efficiency (BTE), brake specific energy consumption (BSEC), exhaust gas temperature (T_exh) were used as the output parameters for the performance model and engine exhaust emissions such as NO_x, smoke and (UBHC) values were used as the output parameters for the emission model. ANN results showed that there is a good correlation between the ANN predicted values and the experimental values for various engine performance parameters and exhaust emission characteristics and the relative mean error values (MRE) were within 8%, which is acceptable.     

Use of bioethanol for biodiesel production

Faced with the energy crisis and environmental degradation, due to the massive use of fossil energy sources, biodiesel is an attractive alternative to diesel fuel. With a view to developing local biodiesel production, using bioethanol as a sustainable reactant for biodiesel production, rather than methanol, is leading to increasing interest, notably in emerging countries. Indeed, bioethanol, which is less toxic than methanol, is produced from local and renewable agricultural resources, being more sustainable and providing access to greater energy independence. However, some issues are limiting the process like purification problems, or the presence of water in bioethanol leading to a drop in yield. Although several studies have already been published on ethyl ester production, most of them primarily focus on homogeneous alkaline catalysis, and report various data. Therefore, this paper aims at presenting a review of previous studies on the subject.     

磁性催化剂Na2O·SiO2/Fe3O4的制备及其催化酯交换反应

以Na2SiO3为活性物质,以纳米Fe3O4为磁核制备磁性固体碱催化剂Na2O·SiO2/Fe3O4,通过正交实验,得到催化剂的最佳制备条件为：硅与铁的摩尔比2.5,晶化时间2h,煅烧温度350℃,煅烧时间2.5h,并通过震动样品磁强计（VSM）对催化剂的磁性进行表征。结果表明,所制备的催化剂Na2O·SiO2/Fe3O4具有较好的磁性和顺磁性,抗水性能优于传统均相碱催化剂;将其应用于棉籽油酯交换反应制备脂肪酸甲酯的最优工艺参数为：醇油摩尔比7：1,催化剂加入量5%,反应温度65℃,反应时间1h,搅拌速度400r/min,在此条件下,催化棉籽油酯交换反应转化率为99.6%,连续使用11次后活性仍在90%以上。     

Application of factorial design in optimization of anion exchange resin based methylation of vegetable oil and fats

A simple, rapid and fairly selective method for the preparation of fatty acid methyl esters (FAMEs) based on anion exchange resin Amberlite IRA-904 catalyzed transesterification of vegetable oil/fat with iodomethane has been described. The vegetable oil and animal fats used were sunflower oil, palm oil, vanaspati (hydrogenated vegetable oil), olive oil, tallow and butter. A Plackett–Burman factorial experimental design was used as a multivariate strategy for the evaluation of the effects of varying several variables at once. The effects of five different variables amount of resin, strength of sodium hydroxide, volume of iodomethane, heating time and temperature of thermostatic water bath, on the yield of fatty acid methyl esters (FAMEs) have been investigated. From these studies, certain variable showed up as significant, and they were optimized by a using 2³ + star central composite design, which involved 16 experiments. The best conditions for transesterification reaction were as follows: amount of resin 2 g, strength of sodium hydroxide 0.25 N, volume of iodomethane 400 µl, heating time 2 min at 70 °C. A standard IUPAC method was used to prepare FAMEs from vegetable oil/fats for comparative purpose. Finally samples of oil/fat obtained from both methods were analysed by Gas liquid chromatography. Analytical results for the FAMEs by resin based proposed method, and conventional IUPAC method showed a good agreement, thus indicating the possibility of using Amberlite IRA-904 based transesterification instead of intensive treatments inherent with the conventional time-consuming methods.

Industrial relevance

Fatty acids are the main components of edible oil and fats, therefore determination of fatty acid composition is so far one of the important parameters for quality evaluation and nutritional value determination of edible oil and fats. The analysis of fatty acid is usually carried out by Gas liquid chromatography (GLC) after conversion of volatile fatty acid methyl esters (FAME) although other ester may be prepared for specific purpose.The endeavor of present work was to improve the FAMEs preparation method, proposing the development of anion exchange resin Amberlite IRA-904 based transesterification of edible oil/fat with iodomethane as alkylating reagent. The present method besides being rapid and reproducible avoids the use of classical saponification, washing of esters and solvent extraction step.     

酶促酯交换椰子油制备富含MCT油脂工艺研究与优化

对脂肪酶Lipozyme RM IM催化癸酸与椰子油酯交换制备富含MCT油脂的工艺条件进行研究。结果表明:在反应温度46℃,底物摩尔比8:1,加酶量6%,加水量15%,反应时间8 h的优化工艺条件下进行多次平行试验,酯交换产物甘三酯中癸酸和MCT质量分数分别达42.31%和50.85%,与原料油相比分别增长37.57%和35.87%。产物甘三酯脂肪酸组成和甘三酯结构分析结果表明,酯交换产物甘三酯中共含有9种MCT成分,主要成分及其在产物甘三酯中的质量分数分别为DLa D(23.57%)、DLa La(16.88%)和DDD(4.83%)等。     

Functionalized oligoesters from poly(3-hydroxyalkanoate)s containing reactive end group for click chemistry: Application to novel copolymer synthesis with poly(2-methyl-2-oxazoline)

Well defined poly(3-hydroxyalkanoates) PHAs containing an alkyne end group were prepared in a one step reaction by direct alcoholysis from natural polyesters using propargyl alcohol. The reactions were allowed to proceed with dibutyltin dilaurate as catalyst at different concentrations from 0.5 up to 24% mol/mol of the alcohol. Oligoesters were obtained with molar masses ranging from 44,500 to 2700 g mol⁻¹. Analysis of the MALDI-TOF mass spectra of the obtained oligomers has revealed the presence of alkyne group on one side and hydroxyl end group on the other side when the reaction was conducted in dried chloroform. The reaction rate of oligomer formation was depending on the nature of the PHAs and decreased with the length of the side chains. The Huisgen 1,3-dipolar cycloaddition has been investigated between the alkyne group of PHAs and 2-azido-2-deoxy-d-glucose or azido-poly(2-methyl-2-oxazoline) (N₃-POXZ). The click reaction allowed the preparation of novel diblock copolymer PHA-b-POXZ soluble in water.     

超临界CO2中脂肪酶催化酯交换反应

建立了一套超临界ＣＯ２中酶催化反应装置，实现了脂肪酶催化苯甲醇与乙酸丁酯的酯交换反应，并分别探讨了压力、水含量、温度和脂肪酶用量对反应速度和转化率的影响以及酶的稳定性。     

Transesterification of tributyrin with methanol over calcium oxide catalysts prepared from various precursors

Calcium oxide catalysts were prepared by calcining various precursors such as calcium acetate, carbonate, hydroxide, nitrate and oxalate and their catalytic activities were examined in the transesterification of tributyrin with methanol. The prepared calcium oxide catalysts were characterized using thermogravimetry (TG), X-ray diffraction (XRD), scanning electron microscopy (SEM), N₂ adsorption and temperature programmed desorption (TPD) of CO₂. The calcium oxide catalyst obtained by calcining calcium hydroxide at 600–800 °C showed the highest tributyrin conversion and methyl butyrate yield. The large desorption peak of CO₂ TPD confirmed that its numerous basic sites were responsible for its high activity. The low-temperature decomposition of calcium hydroxide provided many nano-sized pores with strong basic sites. Although the activity of the calcium oxide catalyst prepared from calcium hydroxide was high, its activity was one order of magnitude less than that of sodium hydroxide catalyst. The dissolution of calcium oxide catalysts in products and their repeated uses were also investigated to discuss their advantages as heterogeneous catalysts in the production of biodiesel.     

关于控制PET／PEN共混物酯交换反应的研究

通过在聚对苯二甲酸乙二酯和聚二甲酸乙二酯的共混体系中加入不同种类,不同含量的热稳定剂或酯交换阻止剂,在300℃左右,经不同时间的熔融共混后取样,再经DSC、NMR测试观察,发现所使用的化学试剂不能阻酯交换反应的发生,酯交换反应程度与所加化学试剂的种类、含量基本夫关,而随熔融共混时间的缩短而受到抑制。