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Synthesis of High-Stability Acidic β/Al-MCM-41 and the Catalytic Performance for the Esterification of Oleic Acid  [PDF]
Zhiping Wang, Shitao Yu
Advances in Chemical Engineering and Science (ACES) , 2016, DOI: 10.4236/aces.2016.64031
Abstract: β/Al-MCM-41 molecular sieve was synthesized and used to catalyze the esterification of oleic acid with short chain alcohols such as methanol, ethanol, isopropanol and isobutanol to obtain biodiesel. The results indicated that β/Al-MCM-41 exhibited the excellent catalytic activity and stability, which was obviously superior to traditional Al-MCM-41. The relationship between acidity and catalytic activity was in detail examined by NH3-TPD and Py-FTIR. Moreover, the kinetics of esterification of oleic acid with methanol showed that the average reaction order n was 1.97 and that activation energy was 50.01 kJ/mol.
Catalytic Esterification of Oleic Acid Over SO42-/MCM-41 Nanostructured Materials  [PDF]
Alexsandra Rodrigues do Nascimento, Gicélia Rodrigues, Joselaine Carvalho Santana, Anne Michelle Garrido Pedrosa, Marcelo José Barros de Souza
Materials Sciences and Applications (MSA) , 2011, DOI: 10.4236/msa.2011.26097
Abstract: This paper deals a study concerning the synthesis and catalytic application of a series of SO42-/MCM-41 catalysts with different SO42-/Si ratios, in the catalytic esterification of oleic acid, aiming biofuels production. The catalysts were characterized by XRD and FT-IR. The catalytic tests were carried out in a batch reactor and the obtained results showed good catalytic activity with high degrees of conversions of oleic acid.
Continuous Catalyst-Free Esterification of Oleic Acid in Compressed Ethanol  [PDF]
Ana Carolina de Araujo Abdala,Vitor Augusto dos Santos Garcia,Caroline Portilho Trentini,Lúcio Cardozo Filho,Edson Antonio da Silva,Camila da Silva
International Journal of Chemical Engineering , 2014, DOI: 10.1155/2014/803783
Abstract: The esterification of oleic acid in a continuous catalyst-free process using compressed ethanol was investigated in the present study. Experiments were performed in a tubular reactor and variables investigated were temperature, pressure, and oleic acid to ethanol molar ratio for different residence time. Results demonstrated that temperature, in the range of 473?K to 573?K, and pressure had a positive effect on fatty acid ethyl esters (FAEE) production. In the experimental range investigated, high conversions can be obtained at low ethanol concentrations in the reaction medium and it was observed that oleic acid to ethanol molar ratios greater than 1?:?6 show no significant increase in conversion. Nonnegligible reaction conversions (>90%) were achieved at 573?K, 20?MPa, oleic acid to ethanol molar ratio of 1?:?6, and 20 minutes of residence time. 1. Introduction Fatty acid, methyl or ethyl, esters can be usually obtained from free fatty acid (FFA) esterification reaction, through vegetable oils hydrolysis followed by the fatty acid esterification or from direct vegetable oils transesterification [1]. The importance of examining the esterification reaction in a more detailed manner is justified by the huge amount and variety of vegetable oils worldwide available for biodiesel production which may have a high percentage of FFA making the conventional alkali-catalyzed transesterification impracticable, since for this process the percentage of FFA needs to be less than 0.5% [2]. Recent studies propose to obtain esters in two reaction steps of substrates with high acidity, consisting of two approaches: (a) esterification of FFA and subsequent transesterification of triglycerides [3–5] or (b) hydrolysis of triglycerides, followed by esterification of fatty acids obtained [6–8]. In these approaches are commonly used chemical catalysts (homogeneous or heterogeneous) or enzymatic catalysts. More recently, the noncatalytic process where is proposed the hydrolysis occurs primarily in subcritical water and subsequent esterification using a solvent in sub- or supercritical [9, 10]. According to the current literature, catalyst-free reactions at high temperature and pressure conditions provide improved phase solubility and decreased mass-transfer limitations; the reaction rate increases significantly in the supercritical state and, thus, the reaction is complete in shorter periods and simpler separation and purification steps [11, 12]. Some studies available in the literature reported the biodiesel production from free fatty acids (FFA) by noncatalytic method at sub-
The oleic acid esterification of policosanol increases its bioavailability and hypocholesterolemic action in rats  [cached]
Haim, D.,Valenzuela, A.,Bra?es, M. C.,Fuenzalida, M.
Grasas y Aceites , 2012, DOI: 10.3989/gya.010612
Abstract: Policosanol comprises a mixture of long-chain aliphatic alcohols from sugarcane wax. More than 50 studies indicate that policosanol decreases serum cholesterol, while others failed to reproduce this effect. The objective of this investigation was to assess the bioavailability of esterified policosanol and non-esterified policosanol (NEP), in relation to their hypocholesterolemic effects. Sprague Dawley rats were given a daily oral dose of 100 mg/kg of NEP, 117 mg kg–1 of butyric acid esterified policosanol (BAEP), or 164 mg kg–1 of oleic acid esterified policosanol (OAEP). Policosanol absorption was evaluated in plasma between 0 and 3 hours after ingestion. To assess changes in total cholesterol, LDL-cholesterol, HDLcholesterol and triacylglycerols in plasma and liver 3-hydroxy- 3-methylglutaryl coenzyme A reductase (HMG- CoA red) phosphorylation, the rats were supplemented with nonesterified or esterified policosanol for 5 weeks. The results indicate that policosanol absorption was significantly greater in OAEP-treated rats than in those subjected to NEP or BAEP administration. OAEP significantly reduced plasma total and LDL-cholesterol in rats, in addition to a 5.6-fold increase (P < 0.05) in the hepatic content of phosphorylated HMG-CoA red over the control values. In conclusion, esterification of policosanol with oleic acid enhances policosanol bioavailability, and significantly improves the serum lipid profile in normocholesterolemic rats in association with the inactivation of HMG-CoA red controlling cholesterogenesis. Los Policosanoles están formados por una mezcla de alcoholes alifáticos de cadena larga y se obtienen de las ceras de la ca a de azúcar. Más de cincuenta estudios indican que los policosanoles reducen el colesterol sérico, mientras que otros no logran reproducir este efecto. El objetivo de esta investigación fue evaluar la biodisponibilidad de policosanoles esterificados y no esterificados (NEP), en relación con sus efectos hipocolesterolémicos. Para ello, a ratas Sprague Dawley se les administró una dosis oral diaria de 100 mg kg–1 de NEP, 117 mg kg–1 de policosanoles esterificados con ácido butírico (BAEP), ó 164 mg kg–1 de policosanoles esterificados con ácido oleico (OAEP). La absorción de los policosanoles se evaluó en el plasma entre 0 y 3 horas después de la ingestión. Para evaluar los cambios en el colesterol total, colesterol-LDL, colesterol-HDL y triglicéridos en el plasma y en la fosforilación de la hígado 3-hidroxi-3-metilglutaril coenzima A reductasa (HMG-CoA red), la ingesta de las ratas fue suplementada con policosano
Esterification of Oleic Acid for Biodiesel Production Catalyzed by SnCl2: A Kinetic Investigation  [PDF]
Abiney L. Cardoso,Soraia Cristina Gonzaga Neves,Marcio J. Da Silva
Energies , 2008, DOI: 10.3390/en1020079
Abstract: The production of biodiesel from low-cost raw materials which generally contain high amounts of free fatty acids (FFAs) is a valuable alternative that would make their production costs more competitive than petroleum-derived fuel. Currently, the production of biodiesel from this kind of raw materials comprises a two-stage process, which requires an initial acid-catalyzed esterification of the FFA, followed by a basecatalyzed transesterification of the triglycerides. Commonly, the acid H 2SO 4 is the catalyst on the first step of this process. It must be said, however, that major drawbacks such as substantial reactor corrosion and the great generation of wastes, including the salts formed due to neutralization of the mineral acid, are negative and virtually unsurmountable aspects of this protocol. In this paper, tin(II) chloride dihydrate (SnCl 2·2H 2O), an inexpensive Lewis acid, was evaluated as catalyst on the ethanolysis of oleic acid, which is the major component of several fat and vegetable oils feedstocks. Tin chloride efficiently promoted the conversion of oleic acid into ethyl oleate in ethanol solution and in soybean oil samples, under mild reaction conditions. The SnCl 2 catalyst was shown to be as active as the mineral acid H 2SO 4. Its use has relevant advantages in comparison to mineral acids catalysts, such as less corrosion of the reactors and as well as avoiding the unnecessary neutralization of products. Herein, the effect of the principal parameters of reaction on the yield and rate of ethyl oleate production has been investigated. Kinetic measurements revealed that the esterification of oleic acid catalyzed by SnCl 2·2H 2O is first-order in relation to both FFAs and catalyst concentration. Experimentally, it was verified that the energy of activation of the esterification reaction of oleic acid catalyzed by SnCl 2 was very close those reported for H 2SO 4.
H3PW12O40 (HPA), an efficient and reusable catalyst for biodiesel production related reactions: esterification of oleic acid and etherification of glycerol
Sepúlveda, Jorge H.;Vera, Carlos R.;Yori, Juan C.;Badano, Juan M.;Santarosa, Daniel;Mandelli, Dalmo;
Química Nova , 2011, DOI: 10.1590/S0100-40422011000400009
Abstract: in esterification of oleic acid with methanol at 25 °c hpa displayed the highest activity. moreover the hpa could be reused after being transformed into its cesium salt. in the reaction of etherification of glycerol hpa and amberlyst 35w showed similar initial activity levels. the results of acid properties demonstrate that hpa is a strong protonic acid and that both surface and bulk protons contribute to the acidity. because of its strong affinity for polar compounds, hpa is also seemingly dissolved in both oleic acid and methanol. the reaction in this case proceeds with the catalyst in the homogenous phase.
Synthesis of tributyl citrate using SO42-/Zr-MCM-41 as catalyst
Zheng Zhifeng, Xu Junming, Jiang Jianchun, Lu Yanju, Huang Yuanbo
Bulletin of the Chemical Society of Ethiopia , 2011,
Abstract: Zirconium-containing mesoporous molecular sieve SO42-/Zr-MCM-41 was synthesized for catalyst in synthesis of tributyl citrate. The structure was characterized by XRD, N2 Ad/De isotherms and FT-IR. The results indicated that the solid acids show good catalytic performance and are reusable. Under optimum conditions and using SO42-/Zr-MCM-41as catalyst, the conversion of citric acid was 95%. After easy separation of the products from the solid acid catalyst, it could be reused three times and gave a conversion of citric acid not less than 92%. The structure of tributyl citrate was characterized by FT-IR and 1H-NMR. KEY WORDS: Mesoporous molecular sieve, Tributyl citrate, Synthesis Bull. Chem. Soc. Ethiop. 2011, 25(1), 147-150.
Synthesis of tributyl citrate using SO42-/Zr-MCM-41 as catalyst
Zheng Zhifeng,Xu Junming,Jiang Jianchun,Lu Yanju
Bulletin of the Chemical Society of Ethiopia , 2011,
Abstract: Zirconium-containing mesoporous molecular sieve SO42-/Zr-MCM-41 was synthesized for catalyst in synthesis of tributyl citrate. The structure was characterized by XRD, N2 Ad/De isotherms and FT-IR. The results indicated that the solid acids show good catalytic performance and are reusable. Under optimum conditions and using SO42-/Zr-MCM-41 as catalyst, the conversion of citric acid was 95%. After easy separation of the products from the solid acid catalyst, it could be reused three times and gave a conversion of citric acid not less than 92%. The structure of tributyl citrate was characterized by FT-IR and 1H-NMR.
Preparation of ordered sulfonated mesoporous polymer (OMP-TsOH) from p-toluenesulfonic acid and application in esterification reaction of fatty acids
Shokrolahi, Arash;Zali, Abbas;Pouretedal, Hamid Reza;Mousaviazar, Ali;
Journal of the Brazilian Chemical Society , 2012, DOI: 10.1590/S0103-50532012000600025
Abstract: sulfonated ordered mesoporous polymer was simply prepared by co-mixing p-formaldehyde, p-toluenesulfonic acid (p-tsoh) and sulfuric acid. sba-15 and/or mcm-48 mesoporous silicas were used as templates. high specific surface area and acid density of the novel solid acids were obtained in the range 900-1400 m2 g-1 and of 4.9 mmol g-1, respectively. catalysts prepared with sba-15 template presented higher pore diameter, and the use of the mcm-48 template is due to higher specific surface area. the catalytic activities of the solid acids were studied in oleic acid esterification reaction. the initial rates of the solid acids with templates of sba-15 and mcm-48 were 80-93 and 62-80 μmol min-1, respectively. catalyst with higher pore diameter showed the higher initial rate of esterification reaction and higher conversion efficiency of oleic acid. consequently, the pore diameter played a crucial role in catalytic activity.
中孔分子筛SO42-/Zr-MCM-41催化裂解聚丙烯反应研究  [PDF]
刘福胜,雷火星,解从霞,于世涛,谢芳菲,葛晓萍
分子催化 , 2007,
Abstract: 采用水热合成法制备了不同硅锆比的中孔分子筛Zr-MCM-41,用强酸性基团SO42-对其进行修饰,制得SO42-/Zr-MCM-41中孔分子筛.采用XRD、FT-IR、NH3-TPD及氮气吸附脱附等技术对其结构和酸强度进行表征.通过改变硅锆比、负载不同的酸性基团对Zr-MCM-41的酸性进行调变,并将其用于催化聚丙烯(PP)的裂解反应,结果表明S i/Zr=40的SO42-/Zr-MCM-41具有较好的催化裂解活性.另外,与热裂解以及HZSM-5和Zr-MCM-41为催化剂时PP的裂解反应结果进行了比较,结果证明SO42-/Zr-MCM-41不仅具有较高的裂解转化率,而且具有较高的液体产物收率,适宜于空间位阻较大的PP的催化裂解反应.
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