Calcined Mg–Al hydrotalcites as solid base catalysts for methanolysis of soybean oil

Abstract Methyl ester of fatty acids, derived from vegetable oils or animal fats and known as biodiesel, is a promising alternative diesel fuel regarding the limited resources of fossil fuel and the environmental concerns. In this work, an environmentally benign process for the methanolysis of soybean oil to methyl esters using calcined Mg–Al hydrotalcites as solid base catalysts in a heterogeneous manner was developed. When the reaction was carried out at reflux of methanol, with a molar ratio of soybean oil to methanol of 15:1, a reaction time 9 h and a catalyst amount 7.5%, the oil conversion was 67%. The calcined hydrotalcite with an Mg/Al ratio of 3.0 derived from calcination at 773 K was found to be the optimum catalyst that can give the highest basicity and the best catalytic activity for this reaction. The catalysts were characterized with SEM, XRD, IR, DTA-TG and Hammett titration method. The activity of the catalysts for the methanolysis reaction was correlated closely with their basicity as determined by the Hammett method.

[1]  B. Gates,et al.  Sulfated zirconia and iron- and manganese-promoted sulfated zirconia: do they protonate alkanes? , 1998 .

[2]  Hak Joo Kim,et al.  TRANSESTERIFICATION OF VEGETABLE OIL TO BIODIESEL USING HETEROGENEOUS BASE CATALYST , 2004 .

[3]  F. Figueras,et al.  Activation of Mg-Al hydrotalcite catalysts for aldol condensation reactions , 1998 .

[4]  A. Corma,et al.  Hydrotalcites as Base Catalysts: Influence of the Chemical Composition and Synthesis Conditions on the Dehydrogenation of Isopropanol , 1994 .

[5]  K. P. Jong,et al.  On the Structure of Activated Hydrotalcites as Solid Base Catalysts for Liquid-Phase Aldol Condensation , 2001 .

[6]  G Antolín,et al.  Optimisation of biodiesel production by sunflower oil transesterification. , 2002, Bioresource technology.

[7]  Sanjib Kumar Karmee,et al.  Preparation of biodiesel from crude oil of Pongamia pinnata. , 2005, Bioresource technology.

[8]  J. M. Rojo,et al.  Thermal decomposition of hydrotalcites. An infrared and nuclear magnetic resonance spectroscopic study , 1992 .

[9]  P. Kuśtrowski,et al.  Acidity and basicity of hydrotalcite derived mixed Mg–Al oxides studied by test reaction of MBOH conversion and temperature programmed desorption of NH3 and CO2 , 2004 .

[10]  S. Kohjiya,et al.  The Polymerization of β-Propiolactone by Calcined Synthetic Hydrotalcite , 1979 .

[11]  U. Schuchardt,et al.  1H nuclear magnetic resonance determination of the yield of the transesterification of rapeseed oil with methanol , 1995 .

[12]  A. Hautfenne.  Standard methods for the analysis of oils, fats and derivatives, 6th Edition. 1st Supplement: Part 5 (1982) Section III, Glycerines. Section IV, Alkaline soaps , 1982 .

[13]  W. Hoelderich,et al.  Preparation of superbases and their use as catalysts for double-bond isomerization , 1999 .

[14]  E. Iglesia,et al.  Structure and Surface and Catalytic Properties of Mg-Al Basic Oxides , 1998 .

[15]  D. Tichit,et al.  The aldol condensation of acetaldehyde and heptanal on hydrotalcite-type catalysts , 2003 .

[16]  M. Kantam,et al.  Henry reactions catalysed by modified Mg–Al hydrotalcite:. an efficient reusable solid base for selective synthesis of β-nitroalkanols† , 1999 .

[17]  P. Kumbhar.  Modified Mg–Al hydrotalcite: a highly active heterogeneous base catalyst for cyanoethylation of alcohols , 1998 .

[18]  Eric J. Doskocil,et al.  Transesterification of soybean oil with zeolite and metal catalysts , 2004 .

[19]  C. A. Henriques,et al.  Hydrotalcites as precursors for Mg,Al-mixed oxides used as catalysts on the aldol condensation of citral with acetone , 2004 .

[20]  J. V. van Bokhoven,et al.  The thermal decomposition of Mg-Al hydrotalcites: effects of interlayer anions and characteristics of the final structure. , 2002, Chemistry.

[21]  S. Kang,et al.  The nature of the thermal decomposition of a catalytically active anionic clay mineral , 1986 .

[22]  Fabrizio Cavani,et al.  Hydrotalcite-type anionic clays: Preparation, properties and applications. , 1991 .

[23]  G. Suppes,et al.  Calcium carbonate catalyzed alcoholysis of fats and oils , 2001 .

[24]  B. Sherriff,et al.  27 Al and 25Mg solid-state magic-angle spinning nuclear magnetic resonance study of hydrotalcite and its thermal decomposition sequence , 1993 .

[25]  Claude Moreau,et al.  Transesterification of rapeseed oil in the presence of basic zeolites and related solid catalysts , 2001 .

[26]  Robert J. Davis,et al.  Characterization of magnesium-aluminum mixed oxides by temperature-programmed reaction of 2-propanol , 1994 .

[27]  M. P. Dorado,et al.  KINETIC PARAMETERS AFFECTING THE ALKALI-CATALYZED TRANSESTERIFICATION PROCESS OF USED OLIVE OIL , 2004 .

[28]  A. S. Ramadhas,et al.  Biodiesel production from high FFA rubber seed oil , 2005 .

[29]  J. Zhu,et al.  Attempts to create new shape-selective solid strong base catalysts , 1999 .

[30]  Jianyi Shen,et al.  Structural and Surface Acid/Base Properties of Hydrotalcite-Derived MgAlO Oxides Calcined at Varying Temperatures , 1998 .

[31]  T. Pinnavaia,et al.  Synthesis and properties of anionic clays pillared by [XM12O40]n− Keggin ions , 1992 .

[32]  E. Garrone,et al.  Textural Properties and Catalytic Activity of Hydrotalcites , 1995 .

[33]  L. Forni.  Comparison of the Methods for the Determination of Surface Acidity of Solid Catalysts , 1974 .

[34]  J. Nagy,et al.  Layered double hydroxides and their pillared derivatives – materials for solid base catalysis; synthesis and characterization , 1999 .