EFFECT OF PHYSICOCHEMICAL PROPERTIES OF d-METAL OXIDES ON SUNFLOWER OIL TRANSESTERIFICATION

The physicochemical indicators of d-metal oxides (NiO, CuO, MnO, FeO, PbO, ZnO) which are heterogeneous catalysts for the transesterification process of sunflower oil triglycerides by ethanol and butan-1-ol have been determined. The available specific surface area, surface acidity and basicity, as well as the hydrogen potential change of the catalyst suspension in water were determined for the oxides. The available specific surface area of the oxides was determined by titration of their aqueous suspension with a solution of methylene blue with a predetermined concentration. The surface acidity and basicity of the catalysts were determined by back titration of samples treated with an aqueous solution of ammonia and acetic acid, respectively. It was found that all investigated d-metal oxides have a low specific surface area. The value of specific surface area is in the range of 0.6-1.5 m2/g. The surface acidity and basicity of the catalysts is 0.13-0.27 mmol/g and 0.019-0.066 mmol/g, respectively. It is shown that the change in the aqueous suspension hydrogen potential of the investigated catalysts relative to the distilled water pH is maximum for NiO and ZnO and it is 0.6-0.65, while for CuO this change is the smallest and it is only 0.3. The character of the pH change curves and the pH values of the oxides suspension in equilibrium condition indicate the presence of weak acid sites in the studied catalysts. The indicated catalysts characteristics are compared with the results obtained in the transesterification process of sunflower oil triglycerides by ethanol and butan-1-ol. It was found that there is a correlation between the surface acidity of catalyst and the reaction initial rate of triglycerides transesterification by ethanol and butan-1-ol. At the same time, such a correlation is absent for the surface basicity of the catalysts. This is consistent with the data on the catalysis of the triglyceride transesterification reaction only by strong major active sites. It is concluded that the transesterification reaction of sunflower oil triglycerides by ethanol and butan-1-ol occurs predominantly on the weak acid centers of the d-metal oxides.

Controlling surface chemistry and mechanical properties of metal ionogels through Lewis acidity and basicity

Gels prepared from metal containing ionic liquids with cross-linked poly(ethylene glycol) have surface compositions and mechanical properties that can be controlled by Lewis basicity and acidity of the metal species.

Effect of surface acidity and basicity of supported Ni catalysts on the N-alkylation of isopropylamine with isopropanol

The N-alkylation of amines with alkylating reagents is widely used in the synthesis of aliphatic amines, which usually be catalyzed by homogeneous catalytic system. In this work, the heterogeneous catalysts...

Grids to Illustrate Induction and Resonance Effects: Aromatic Acidity and Basicity

The effect of substituents on the acidity of benzoic acids and anilines has been organized in grids to demonstrate the inductive and resonance effects. The relation between structure and pKa is emphasized by a new educational process: the Search-Organize-Predict (SOP) procedure.

Grids to Illustrate Induction and Resonance Effects: Aromatic Acidity and Basicity

The effect of substituents on the acidity of benzoic acids and anilines has been organized in grids to demonstrate the inductive and resonance effects. The relation between structure and pKa is emphasized by a new educational process: the Search-Organize-Predict (SOP) procedure.