Transesterification of triglycerides by ethanol in the presence of metal oxides

Abstract

The aim of the research was to determine a regularities of the transesterification process of sunflower oil triglycerides by ethanol in the presence of catalysts-oxides of zinc (ZnO), nickel (NiO), iron (FeO), copper (CuO) and cobalt (Co3O4 and Co2O3). The research was carried out at a temperature of 338 K and a molar ratio of triglycerides: ethanol 1 : (3.8-4.1). It is established that the kind of metal oxide affects both the initial reaction rate and the achieved triglycerides conversion. It is shown that the highest amount of triglycerides reacts during the first 30 minutes with conversion achieving from 39.5 % (in the presence of Co2O3) to 76.7 % (ZnO). In the next 120 minutes the smallest increase of the triglycerides conversion is 18.6 % in the presence of ZnO and the largest increase is 30.6% in the case of CuO catalysis. According to the research results a number of metal oxides activities in the transesterification reaction of triglycerides by ethanol were proposed. It was found that zinc and nickel oxides demonstrate the highest activity in the transesterification reaction of sunflower oil triglycerides by ethanol. In their presence the triglycerides conversion is achieved 95.3 and 94.2% for 150 minutes of the reaction, respectively. At the same time the lowest activity is detected by cobalt oxides. It is shown that the established regularities of the activity change of metal oxides correlate with the results obtained during the study of triglycerides transesterification by ethanol in the presence of cation exchange resin KU-2-8 with immobilized metal ions. Exception is cation exchange resin with immobilized ions of cobalt (II), which unlike cobalt oxides exhibits a sufficiently high catalytic activity. The effect of the reagents molar ratio on the raw materials conversion in the presence of the most active catalyst (zinc oxide) was investigated. It was found that an increase in the molar ratio of triglycerides: ethanol from 1 : 3.8 to 1 : 4.1 affects both the initial reaction rate and the maximum triglycerides conversion. It is shown that even a small increase of the molar ratio of triglycerides: ethanol can increase the triglycerides conversion on 2.5%. The performed research shows a possibility of zinc and nickel oxides using in the transesterification reaction of triglycerides by ethanol.

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Kinetic and technological aspects of butyloleate production in the presence of metal oxides

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