Alkylguanidine-catalyzed heterogeneous transesterification of soybean oil (original) (raw)
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Transesterification of soybean oil on guanidine base-functionalized SBA-15 catalysts
Applied Catalysis B: Environmental, 2011
a b s t r a c t SBA-15 functionalization with the guanidine base 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD) was used to prepare TBD-grafted catalysts for the soybean oil transesterification reaction. The structural and textural features of both the support and the catalysts were investigated by X-ray diffraction, transmission electron microscopy, and nitrogen physisorption. CHN analysis and FTIR characterization were also carried out on the catalysts before and after reaction. Potentiometric titration was also used to confirm CHN analysis data for the fresh catalysts. Mild conditions (atmospheric pressure and 343 K) were chosen for catalytic testing in a batch reactor. The influence of the base content and the reaction time on the methyl esters yield was investigated. All the catalysts were found active for the soybean oil conversion. Comparison with the catalytic behaviour of a commercial TBD-grafted polymer showed a superior performance of the functionalized SBA-15 catalysts. The higher the functionalization extent, the higher the activity, just a few hours being required for a 100 mol% methyl esters yield. Over such a short reaction time leaching was observed to occur only to an extremely low extent, which makes possible to reuse the catalysts after a regeneration step consisting in a simple NaOH treatment of the recovered samples. During such treatment the catalyst base sites -poisoned (through protonation) by the free fatty acids -are freed, and their activity is restored.
Applied Catalysis A: General, 2008
Um catalisador baseado em sílica quimicamente modificada com tetrametilguanidina (TMG) foi sintetizado pela co-condensação de tetraetilortossilicato (TEOS) com um novo agente sililante, preparado pela reação entre a molécula TMG e (3-cloropropil)trimetoxisilano. O direcionador n-dodecilamina foi utilizado para organizar a polimerização do catalisador inorgânico-orgânico. A termogravimetria mostrou que o número de sítios ativos do catalisador foi de 1,35 mmol g-1 , com uma área superficial de 811 ± 75 m 2 g-1. A espectroscopia na região do infravermelho e de ressonância magnética nuclear no estado sólido para os núcleos 29 Si e 13 C confirmou a obtenção do produto desejado. Este material foi usado para catalisar a adição de nitrometano em ciclopentenona. 98% de conversão foi observada depois de 3 h de reação. O catalisador foi recuperado e reutilizado por mais catorze vezes, mantendo uma eficiência catalítica em torno de 98%. A catalyst based on silica chemically modified with tetramethylguanidine (TMG) was synthesized by the co-condensation of tetraethylorthosilicate (TEOS) with a new silylant agent derived from the reaction between the TMG molecule and (3-chloropropyl)trimethoxysilane. A neutral n-dodecylamine template was used to organize the polymerization of the inorganicorganic catalyst. Thermogravimetry showed that the number of active pendant groups in the catalyst was 1.35 mmol g-1 , with a surface area of 811 ± 75 m 2 g-1. Infrared spectroscopy and 13 C and 29 Si nuclear magnetic resonance data are in agreement with the proposed structure. This material has been used to catalyse the addition of nitromethane to cyclopentenone. The catalytic efficiency was followed and the nitromethylcyclopentanone conversion presented a yield of 98% at 3 h of reaction. The catalyst was recovered and reused 14 times, maintaining about 98% of its catalytic efficiency.
Tetramethylguanidine as an efficient catalyst for transesterification of waste frying oils
Applied Energy, 2011
New catalysts and environmentally benign processes may lead to methyl ester production with improved properties at competitive costs. In this study, transesterification of waste frying oil to biodiesel using tetramethylguanidine as a strong base catalyst was conducted. The influence of catalyst concentration and of certain physicochemical properties of waste frying oil was investigated. Experiments were also performed on a semi-refined cottonseed oil for comparison purposes. Experimental results showed that methyl ester conversion was dependent on the type of oil, catalyst concentration and reaction time.
Transesterification of vegetable oils: a review
Journal of The Brazilian Chemical Society, 1998
A transesterificação de óleos vegetais com metanol, bem como as principais aplicações de ésteres metílicos de ácidos graxos, são revisadas. São descritos os aspectos gerais desse processo e a aplicabilidade de diferentes tipos de catalisadores (ácidos, hidróxidos, alcóxidos e carbonatos de metais alcalinos, enzimas e bases não-iônicas, como aminas, amidinas, guanidinas e triamino(imino)fosforanos). Enfoque especial é dado às guanidinas, que podem ser facilmente heterogeneizadas em polímeros orgânicos. No entanto, as bases ancoradas lixiviam dos polímeros. Novas estratégias para a obtenção de guanidinas heterogeneizadas mais resistentes à lixiviação são propostas. Finalmente, são descritas várias aplicações para ésteres de ácidos graxos, obtidos por transesterificação de óleos vegetais.
Transesterification of soybean oil with methanol catalyzed by basic solids
Catalysis Today, 2008
The fatty acid methyl esters prepared by transesterification of vegetable oils with methanol are products of commercial interest due to their use as raw materials for chemical, pharmaceutical and food industries and also as biodiesel. Biodiesel is a non-polluting alternative fuel produced from renewable resources whose chemical and physical properties closely resemble those of the petroleum diesel fuel. This work studied the transesterification of soybean oil with methanol over basic solid catalysts such as: MgO, ZnO, Al 2 O 3 , and mixed oxides derived from hydrotalcitelike compounds (Mg/Al and Zn/Mg/Al). The influence of the catalyst basicity on their catalytic performance was also evaluated. The results indicated that both MgO and mixed oxides were efficient to catalyze the reaction under study with a fatty acid methyl esters yield higher than 60% at 130 8C. The influence of chemical composition on catalytic performance was closely related to the density of basic sites of the samples. The fatty acid methyl esters yield was favored by the increase on reaction temperature.
Reactive & Functional Polymers, 2010
Polycationic systems based on poly(hexamethylene biguanide) (PHMBG), branched polyethyleneimine (PEI) and poly(N-vinylguanidine) (PVG) have been evaluated as heterogeneous catalysts for the transesterification of sunflower oil by methanol. Insoluble networks are synthesized via cross-linking of PHMBG by either 4,4′-methylenebis(N,N-diglycidylaniline) or polyisocyanate prepolymer, PEI with sebacoyl chloride, and PVG with 1,4-butanediol diglycidyl ether. PHMBG and its cross-linked networks appeared to be remarkably efficient catalysts, enabling 80–100% triglyceride conversion within 0.5 h at 70 °C. PEI-based networks catalyzed triglyceride transesterification with rates 8- to 12-fold slower than their PHMBG-based counterparts. The PVG-based networks, which were devoid of hydrophobic moieties, appeared to be inefficient catalysts due to limited accessibility of the basic guanidine groups to reactants. The PHMBG networks were shown to be recyclable by a simple centrifugal filtration. After 15 cycles of recovery and reuse, only 10–15% decline in performance was observed.
Transesterification of Soybean Oil Using Heterogeneous Catalysts
Energy & Fuels, 2008
Biodiesel is a biodegradable, nontoxic, and clean-burning fuel that can be made from biorenewable fats and oils. At present, biodiesel is primarily produced in batch reactors, where the separation of catalysts, glycerol, and biodiesel from the reactor is onerous. Solid catalysts can be used to allay this separation problem. In the present study, seven different solid catalysts (metal oxides), MgO, CaO, PbO, PbO 2 , Pb 3 O 4 , Tl 2 O 3 , and ZnO, with different Brunauer-Emmett-Teller (BET) surface area, acidity/basicity, and the acid/base site strength were selected for the transesterification. Biodiesel (fatty acid methyl esters, FAMEs) yields were determined for these catalysts at three different temperatures (75, 150, and 225°C) and high pressure. It was observed that more than 89% yield of biodiesel was achieved with PbO and PbO 2 solid catalysts.
Transesterification of soybean oil with zeolite and metal catalysts
Applied Catalysis A: General, 2004
Transesterification of soybean oil with methanol was carried out at 60, 120, and 150 • C in the presence of a series NaX faujasite zeolite, ETS-10 zeolite, and metal catalysts. The stock zeolites were exchanged with potassium and cesium; NaX containing occluded sodium oxide (NaO x /NaX) and occluded sodium azide (NaO x /NaX * ). The catalysts were calcined at 500 • C prior to use in order to increase activity. The ETS-10 catalysts provided higher conversions than the Zeolite-X type catalysts. The increased conversions were attributed to the higher basicity of ETS-10 zeolites and larger pore structures that improved intra-particle diffusion. Methyl ester yield increased with an increase in temperature from 60 to 150 • C. The metal catalysts increased conversion by one to over two orders of magnitude over the homogeneous reaction with several of the zeolite catalysts performing better than the metal catalysts. The catalyst was reused without observed loss of activity. A preliminary design assessment shows that these catalysts are sufficiently active to be commercially viable contingent upon the costs of the catalysts achieving conversions in excess of 90% at temperatures below 125 • C.
Transesterification of Soybean Oil to Biodiesel by Using Heterogeneous Basic Catalysts
Industrial & Engineering Chemistry Research, 2006
This study uses waste silicone as a low-cost material to prepare the solid base catalyst using Li 2 CO 3 as an activating agent through a solid state reaction for the biodiesel production. A sample of waste silicone is converted into SiO 2 powder by being heated at 800 o C for 4 h. The results show that a highly active solid catalyst could be obtained by mixing and well grinding SiO 2 powder with Li 2 CO 3 calcined in air for 4 h. The prepared solid base catalysts are characterized by XRD, BET, SEM and FTIR for the physical and chemical properties. In the present study, the biodiesel is synthesized from soybean oil through a transesterification reaction catalyzed by the solid base catalyst. Under the optimal reaction conditions of methanol/oil molar ratio 12:1, 6% (wt/wt oil) catalyst amount, and a reaction temperature of 62 o C for 3 h, there is a 99.04 ± 0.9% conversion to the biodiesel from soybean oil. The waste silicone as the solid base catalyst demonstrates excellent catalytic activities and stable catalytic activities in transesterification reactions.
Chemical Industry and Chemical Engineering Quarterly
The manganese carbonate catalyst, prepared by precipitation method, was used in transesterification of soybean oil under subcritical condition of methanol. Catalyst samples were characterized by X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy, scanning electron microscopy (SEM) with energy dispersive spectroscopy (EDS). The triacylglycerol (TAG) conversion and fatty acid methyl esters (FAME) yield were determined using high performance liquid chromatography (HPLC). The transesterification was realized for 1 h using various working conditions: 0-3 wt.% of catalyst (based on the mass of oil), the mole ratio of methanol to oil from 13:1 to 27:1 and temperature ranging from 393 to 473 K. A maximum TAG conversion of 98.1% could be obtained at the optimal reaction conditions: 2 wt.% of catalyst, methanol/oil mole ratio of 21:1, for 1 h in a batch reactor at 453 K. Kinetic analysis showed that the model based on mass transfer and chemical reaction at the catalyst s...