动物油在不同催化剂上的转化

在固定床微反装置内,对动物油在USY,HZSM-5,ANA,Al2O3和SiO2催化剂上的反应行为进行了研究.结果表明,脂肪酸酯分子一般先发生脱羧和脱羰反应(主要是C-O键的断裂),初始裂化反应产生的大分子烃类及其含氧衍生物会在催化剂的酸性位上发生二次裂化和脱氧等反应.USY和HZSM-5分子筛的酸性强,有利于二次裂化,生成较多的液化气和汽油;在具有弱酸位、大孔的Al2O3催化剂上,发生温和的二次裂化反应,转化率略低;而在非酸性的大孔SiO2催化剂及无孔的ANA分子筛上,二次裂化反应被显著抑制,转化率更低,产物中存在大量的含氧衍生物.热裂化反应会产生较多的CO2,而催化裂化反应会产生相对较多的CO.     

基于纤维素的固体酸催化剂的制备及其催化高酸值废油脂生产生物柴油

以廉价的纤维素为原料,经不完全炭化和磺化制得含高密度(1.69 mmol/g) SO3H基团的固体酸催化剂Cellulose-SO3H.结果表明,该催化剂适宜的制备条件为:在400℃炭化15h,再在150℃磺化15h.所得催化剂在油酸与甲醇的酯化反应中表现出明显高于其它几种典型固体酸催化剂(铌酸,Amberlyst- ...     

Hierarchical Zeolites as Catalysts for Biodiesel Production from Waste Frying Oils to Overcome Mass Transfer Limitations

Hierarchical crystals with short diffusion path, conventional microcrystals and nanocrystals of ZSM-5 zeolites were used for biodiesel production from waste frying oils and were assessed for their catalytic activity in regard to their pore structure and acidic properties. Produced zeolites were characterized using XRD, nitrogen adsorption–desorption, SEM, TEM, X-ray fluorescence, and FTIR. Pore size effect on molecular diffusion limitation was assessed by Thiele modulus calculations and turnover frequencies (TOF) were used to discuss the correlation between acidic character and catalytic performance of the zeolites. Owing to the enhanced accessibility and mass transfer of triglycerides and free fatty acids to the elemental active zeolitic structure, the catalytic performance of nanosponge and nanosheet hierarchical zeolites was the highest. A maximum yield of 48.29% was reached for the transesterification of waste frying oils (WFOs) using HZSM-5 nanosheets at 12:1 methanol to WFOs molar ratio, 180 °C, 10 wt % catalyst loading, and 4 h reaction time. Although HZSM-5 nanosponges achieved high conversions, these more hydrophilic zeolites did not function according to their entire acidic strength in comparison to HZSM-5 nanosheets. NSh-HZSM5 catalytic performance was still high after 4 consecutive cycles as a result of the zeolite regeneration.     

废动植物油脂制备烷醇酰胺的研究

以废动植物油脂为原料,在自制DYD催化剂作用下制得脂肪酸甲酯,再以氢氧化钾为催化剂,与二乙醇胺合成烷醇酰胺。考察了反应温度、反应时间、催化剂用量、真空度等因素对反应的影响,通过单因素实验和析因实验确定最佳工艺条件为:甲酯/二乙醇胺物质的量比1∶1.55,反应温度110℃,反应时间2.5 h,真空度0.08 MPa,催化剂用量0.65%(相对于脂肪酸甲酯的质量),烷醇酰胺的收率达96.3%。通过红外光谱对产物结构进行了表征,并对界面张力进行了测定。结果表明,产物具有较好的界面活性。     

The Obtaining Biodiesel from Used Vegetable Oil and Animal Waste Oil by Two Stages Transesterification Reaction

The biodiesel was obtained from used vegetable oil (UVO) and animal waste oil (AWO) by the two stages transesterification reaction. Also chemical and technical properties of feed and products were determined. Conditions of transesterification reaction for each of the oil samples were determined as a result of several sets of experiments. The suitable conditions of transesterification reaction were the following. Hereto a molar ratio of oil: methanol: catalyst was 1: 6: 1/40, for 30 min, at temperature of 600°C. To obtain biodiesel directly by the one stage transesterification, in case of using UVO sample, when the acidity number of feed oil had to less than 3 mg KOH/g. The biodiesel from UVO and AWO was prepared by mixing 5, 10, 20% of volume in the summer and winter diesel fuel. However, the product from mixture of UVO and winter diesel fuel met the technique requirements both of winter and summer diesel fuel, but the product from mixture of AWO and summer diesel fuel did not satisfy technical requirements of diesel fuel.     

氧化钙和氟化钾负载高岭土固体碱催化制备新型生物柴油

以高岭土为载体,利用浸渍法制备了氧化钙和氟化钾负载高岭土固体碱(GCK);利用X射线粉末衍射(XRD)、扫描电子显微镜(SEM)、红外光谱(FT-IR)和哈密特指示剂法等技术手段对催化剂进行表征;考察了KF负载量和反应条件对月桂酸甲酯(ML)与乙二醇单甲醚(EGME)酯交换反应制备新型生物柴油产率的影响。 结果表明,GCK碱强度(H_)在7.2~18.4之间,KCaF₃为主要活性组分,当氟化钾负载量为25%、EGME与ML摩尔比3.0、催化剂用量相对于ML的质量分数为4.5 %、120 ℃下反应2 h,新型生物柴油的收率高达97.1%。 最后对催化剂的重复利用性能进行了考察。     

Application of Flying Jet Plasma for Production of Biodiesel Fuel from Wasted Vegetable Oil

Biodiesel, a good partial or total substitute for petrodiesel, is a renewable clean burning fuel which can be produced from transesterification of vegetable oils and animal fats with an alcohol in presence of a catalyst. Since the feedstock costs in this process constitutes more than 70 % of the overall cost, use of wasted vegetable oil (i.e. consumed cooking oil) for biodiesel production is a big challenge in terms of cost reduction and environmental impacts. Nonetheless, the content of residues in the wasted vegetable oil, formed during frying, is a major drawback could be faced in this direction. In this research, we applied an unconventional design of flying jet dielectric barrier discharge plasma torch to treat several specimens of wasted cooking oil collected from different resources before transesterification. In other experiments, the jet plasma itself was used to catalyze the reaction process. The examined plasma torch was found more feasible than conventional DBD reactor design in terms of gas and power consumptions. Upon inducting plasma treatment, the transesterification process resulted in higher biodiesel yield, lower reaction time and easier product separation than the conventional path. Upon catalyzing the reaction by the sole jet plasma effect, the biodiesel content of saturated methyl esters was higher than conventional tranesterification. Also, the yield and properties were found within commercial standards.     

The Novel Porous Tissue-Like Carbon-Based Solid Acid for Biodiesel Synthesis from Waste Oil

Kinetics and Catalysis - The novel porous tissue-like carbon based solid acid has been synthesized by the molten salt-induced carbonization and sulfonation. The novel solid acid owned the special...     

固体酸催化剂对二甲醚水蒸气重整制氢过程的影响

将 HZSM-5 (n(SiO2)/n(Al2O3) = 25, 38, 50 和 93.5), HM, Hβ, HY 和γ-Al2O3 等多种固体酸催化剂用于二甲醚(DME)水解, 并将其分别同自制的 CuO/ZnO/Al2O3 催化剂进行机械混合, 制备双功能催化剂并用于 DME 水蒸气重整制氢反应. 结合 NH3 程序升温脱附表征手段, 考察了固体酸催化剂酸性位的强度、酸量及种类对 DME 水解和重整反应的影响;结合热重-差热扫描量热分析表征手段, 研究了 HZSM-5(93.5)和γ-Al2O3 在 DME 水解过程中的稳定性. 在此基础上, 进一步研究了固体酸催化剂对 DME 重整制氢反应中 DME 转化率、H2 摩尔产率以及含碳气体产物选择性的影响. 结果表明, 固体酸催化剂的酸性位的强度和酸量对 DME 重整制氢过程具有显著的影响, 强酸度和高酸量无益于 DME 水蒸气重整制氢;以 HZSM-5 为固体酸的双功能催化剂具有较好的低温活性, 而以γ-Al2O3 为固体酸的双功能催化剂在高温下具有较高的 H2 产率.     

The Formation and Reactions of Hydrogen Cyanide During Isobutane-SCR over Fe-MFI Catalysts

The extent to which HCN is produced as a significant product during isobutane-SCR over Fe-MFI catalysts has been investigated together with its origin and further conversion. Catalysts made by both vapor-phase sublimation and solid-state ion exchange can produce well over 100-ppm HCN, which is a major intermediate for N₂ production, but the peak concentration is less with the former material due to a higher oxidation activity. HCN production is confined to temperatures giving partial conversion of isobutane, when deposited material suppresses the very high intrinsic activity of Fe-MFI for the further conversion of HCN to N₂, largely via hydrolysis to ammonia and NH₃-SCR. Activity for the oxidation of NO to NO₂ is similarly suppressed. This oxidation step is likely to be the rate determining one in isobutane-SCR rather than the activation of the alkane since there is no deuterium kinetic isotope effect. Decomposition of isobutyronitrile, formed by dehydration of a primary nitroso species via its oxime tautomer, is a possible source of HCN. This decomposition gives propene as a coproduct, which reacts completely during isobutane-SCR and may also be a source of deposits through oligomerization. Secondary and tertiary nitroso intermediates cannot react in this way and, based on the reactions of nitroanalogues, are more likely to undergo elimination to form alkenes. The overall effect is to convert alkane-SCR to SCR with alkenes containing the same number or one less carbon atom.     

Application of a Chitosan-Immobilized Talaromyces thermophilus Lipase to a Batch Biodiesel Production from Waste Frying Oils

Waste frying oil, which not only harms people’s health but also causes environmental pollution, can be a good alternative to partially substitute petroleum diesel through transesterification reaction. This oil contained 8.8 % of free fatty acids, which cause a problem in a base-catalyzed process. In this study, synthesis of biodiesel was efficiently catalyzed by the covalently immobilized Talaromyces thermophilus lipase and allowed bioconversion yield up to 92 % after 24 h of reaction time. The optimal molar ratio was four to six parts of methanol to one part of oil with a biocatalyst loaded of 25 wt.% of oil. Further, experiments revealed that T. thermophilus lipase, immobilized by a multipoint covalent liaison onto activated chitosan via a short spacer (glutaraldehyde), was sufficiently tolerant to methanol. In fact, using the stepwise addition of methanol, no significant difference was observed from the one-step whole addition at the start of reaction. The batch biodiesel synthesis was performed in a fixed bed reactor with a lipase loaded of 10 g. The bioconversion yield of 98 % was attained after a 5-h reaction time. The bioreactor was operated successfully for almost 150 h without any changes in the initial conversion yield. Most of the chemical and physical properties of the produced biodiesel meet the European and USA standard specifications of biodiesel fuels.     

Synthesis and Characterization of Polymeric Materials from Vegetable Oils

Although the petrochemical polymers have revolutionized the technological development, the intensive use of these materials have contributed to the global pollution. In this context, researches involving ecofriendliness materials are growing up, as well as, a current interest in developing materials from inexpensive and renewable resources, such as vegetable oils. In this work, is described the synthesis of polymeric materials by thermal polymerization from linseed oil (Linum usitatissimum L.) and passion fruit oil (Passiflora edulis) and their characterization by gas chromatographic (GC), Fourier transform infrared (FTIR) spectroscopy, solubility in organic solvents, thermogravimetry (TG), differential scanning calorimetry (DSC) and Raman spectroscopy. The TG curve shows that those polymeric materials present two stages of decomposition. DSC plots of the vegetable oils showed some endothermic and exothermic transitions which are not present in the DSC curves corresponding to oil-based polymers. The Raman spectra of the polymers indicate declining of absorbance in the region of CC stretching (∼1600 cm⁻¹). This absorption was used to estimate the degree of polymerization (79% and 67.5% for linseed and passion fruit oils, respectively).     

Production of Oils from Acetic Acid by the Oleaginous Yeast Cryptococcus curvatus

The feasibility of the conversion of acetic acid, a metabolite commonly obtained during anaerobic fermentation processes, into oils using the yeast Cryptococcus curvatus was reported. This microorganism exhibited very slow growth rates on acetate as carbon source, which led to design a two-stage cultivation process. The first consisted of cell growth on glucose as carbon source until its complete exhaustion. The second step involved the use of acetate as carbon source under nitrogen limitation in order to induce lipid accumulation. A typical experiment performed in a bioreactor involved a preliminary yeast growth with a glucose initial concentration of 15?g/L glucose. Further additions of acetate and nitrogen source allowed a final lipid accumulation up to 50% (w/w). These promising results demonstrated the suitability of the technique proposed.     

Production of Biodiesel via Enzymatic Ethanolysis of the Sunflower and Soybean Oils: Modeling

Biodiesel has become attractive due to its environmental benefits compared with conventional diesel. Although the enzymatic synthesis of biodiesel requires low thermal energy, low conversions of enzymatic transesterification with ethanol (ethanolysis) of oils to produce biodiesel are reported as a result of deactivation of the enzyme depending on the reaction conditions. The synthesis of biodiesel via enzymatic ethanolysis of sunflower and soybean oils was investigated. Kinetic parameters for the overall reactions were fitted to experimental data available in the literature with the Ping Pong Bi-Bi mechanism including the inhibition effect of the ethanol on the activity of lipase Novozyme® 435. The model was applied to a batch reactor and the experimental conversions were successfully reproduced. The modeling of a semibatch reactor with continuous addition of ethanol was also performed and the results showed a reduction of roughly 3 h in the reaction time in comparison with the batch-wise operation.     

Sulfide Catalysts for Production of Motor Fuels from Fatty Acid Triglycerides

Patents dealing with the production of motor fuel components by hydrodeoxygenation of renewable raw materials based on fatty acid triglycerides are analyzed. Various methods of using sulfide catalysts in hydrodeoxygenation of fatty acid triglycerides and of their mixtures with petroleum fractions are described. The ways to overcome problems that arise in hydrodeoxygenation, based on using sulfide catalysts differing in the active component and support composition, are considered. For example, the use of supported MoS₂ catalysts free of Co and Ni ensures the conversion of fatty acid triglycerides along the “direct hydrodeoxygenation” pathway to avoid the formation of carbon oxides and related process problems. The use of sulfide catalysts on zeolite-containing supports allows synthesis of products with improved low-temperature properties due to isomerization (or mild hydrocracking) of С₁₅–С₁₈ alkanes formed by hydrodeoxygenation of fatty acid triglycerides.

     

Isolation of Novel Microalgae from Acid Mine Drainage and Its Potential Application for Biodiesel Production

Microalgae were selected and isolated from acid mine drainage in order to find microalgae species which could be cultivated in low pH condition. In the present investigation, 30 microalgae were isolated from ten locations of acid mine drainage in South Korea. Four microalgae were selected based on their growth rate, morphology, and identified as strains of KGE1, KGE3, KGE4, and KGE7. The dry biomass of microalgae species ranged between 1 and 2 g L^?1 after 21 days of cultivation. The growth kinetics of microalgae was well described by logistic growth model. Among these, KGE7 has the highest biomass production (2.05?±?0.35 g L^?1), lipid productivity (0.82?±?0.14 g L^?1), and C16–C18 fatty acid contents (97.6 %). These results suggest that Scenedesmus sp. KGE 7 can be utilized for biodiesel production based on its high biomass and lipid productivity.     

Insights into the Active Acid Sites for Isosorbide Synthesis from Renewable Sorbitol and Cellulose on Solid Acid Catalysts

Sustainable synthesis of isosorbide, an important renewable platform chemical, from sorbitol and cellulose, has attracted increasing attention, but still remains challenging. Here, we have studied the effects of the acidity on the dehydration of sorbitol in water on a variety of solid acids, including zeolites, sulfonic materials, montmorillonite and mixed SiO₂-Al₂O₃ oxide. These solid acids showed markedly different activities, which were found to be closely related to their strong Brønsted acid sites, while the weak Brønsted acid and Lewis acid sites were essentially inactive. Different from the other solid acids examined, H-ZSM-5 zeolites in a wide range of Si/Al molar ratios(25-300) exhibited superior selectivities to isosorbide in dehydration of sorbitol, consistent with the observed difference in their formation rates of the 1,4-sortbitan and 3,6-sorbitan intermediates. Kinetic studies on the sorbitol dehydration showed that 3,6-sorbitan, once it formed, dehydrated to isosorbide more readily than 1,4-sorbitan by a factor of 19, and the formation rate constant of 3,6-sorbitan on H-ZSM-5(Si/Al=25) was about three times higher than that of H-Beta(Si/Al=25). Such favorable formation of the reactive 3,6-sorbitan intermediate and the higher isosorbide selectivity on H-ZSM-5 appear to be induced by its confined pore structure composed of the paired 5-membered rings. H-ZSM-5 was also found to be efficient for the direct conversion of cellulose to isosorbide in coupling with Ru/C hydrogenation catalyst. This work provides fundamental insights into the acidity and pore structures that are helpful for the design of novel solid acids toward the efficient synthesis of isosorbide from the dehydration of sorbitol and even directly from the tandem reaction of cellulose.     

A Green Synthesis of 2-Ethylanthraquinone by Dehydration of 2-(4''''-ethylbenzoyl) benzoic Acid over Solid Acid Catalysts

2-EAQ is an important intermediate for the synthesis of hydrogen peroxide, pharmaceu- ticals, pesticides, and dyes. With the increasing demand for hydrogen peroxide, it needs to enhance the yields of 2-EAQ. However, in the conventional process, concentrated H2SO41-2 is employed as the catalyst in the dehydration of BE acid for the synthesis of 2-EAQ, which produces a series of environmental impacts and safety concerns. For these reasons, a substitute process, which has little or no hazard…     

Production and Characterization of Biodiesel from Tung Oil

The feasibility of biodiesel production from tung oil was investigated. The esterification reaction of the free fatty acids of tung oil was performed using Amberlyst-15. Optimal molar ratio of methanol to oil was determined to be 7.5:1, and Amberlyst-15 was 20.8wt% of oil by response surface methodology. Under these reaction conditions, the acid value of tung oil was reduced to 0.72mg KOH/g. In the range of the molar equivalents of methanol to oil under 5, the esterification was strongly affected by the amount of methanol but not the catalyst. When the molar ratio of methanol to oil was 4.1:1 and Amberlyst-15 was 29.8wt% of the oil, the acid value decreased to 0.85mg KOH/g. After the transesterification reaction of pretreated tung oil, the purity of tung biodiesel was 90.2wt%. The high viscosity of crude tung oil decreased to 9.8mm²/s at 40 °C. Because of the presence of eleostearic acid, which is a main component of tung oil, the oxidation stability as determined by the Rancimat method was very low, 0.5h, but the cold filter plugging point, −11 °C, was good. The distillation process did not improve the fatty acid methyl ester content and the viscosity.