Research Information System
Thesis Type: Postgraduate
Institution Of The Thesis: Gazi Üniversitesi, Fen Bilimleri Enstitüsü, Turkey
Approval Date: 2016
Student: FERİDE KURU
Supervisor: NURAY OKTAR
Abstract:In this study, the etherification reaction of glycerol (G) with tert-butyl alcohol (TBA) has been carried out. The aim of this study is to obtain ethers (mono-, di- and tri-ethers) of glycerol which are fuel/fuel additives with high octone/cetane numbers. Purolite CT 175, Amberlite IR 120, Dowex DR Monosphere 2030, Monosphere Dowex M 31, Relite EXC8D and Lewatit K 2629, which are commercial and acidic ion exchange resin catalysts' activities, have been determined in the etherification reaction of glycerol (G) with tert-butyl alcohol (TBA). The experimental works have been carried out in liquid phase, in a batch reactor at autogenous pressure and 90-120 °C temperature range with different molar ratio (TBA/G= 3/1, 5/1, 8/1). The effects of temperatures, different reactant molar ratios and types of catalyst on glycerol conversion and the product distribution have been investigated. Glycerol conversion, selectivities of di-ether and tri-ether increased with an increase in the temperature and TBA/G molar ratio. Although tri-ether had a tendency to increase, it occured in trace amounts in the reactions. Also, the selectivity of mono-ether decreased with an increase in the temperature and TBA/G molar ratio. In the batch reactor, at 120 °C and TBA/G= 8/1 molar ratio, activities of the catalysts were compared. The order of the catalytic activities was found as Relite EXC8D=Lewatit K 2629=Dowex Monosphere DR 2030>Purolite CT 175>Amberlite IR 120>Dowex Monosphere M 31. Complete conversion of glycerol (100%) was observed in the presence of Dowex Monosphere DR 2030, Relite EXC8D and Lewatit K 2629. According to the experimental results, the highest selectivity of di-ether (0.44) was observed in the presence of Dowex Monosphere DR 2030 at 120 °C and TBA/G= 3/1 molar ratio. Dowex Monosphere DR 2030, Relite EXC8D and Lewatit K 2629 have higher surface area and ion exchange capacity than other resins. Moreover, in this study, the etherification reaction of glycerol (G) with different alcohol (isopropanol, n-propanol) has been carried out in batch reactor, in the presence of Amberlite IR 120, Purolite CT 175 and Amberlite 15, and glycerol conversions were not observed. Finally, the etherification of glycerol with TBA was investigated in a continuous flow reactor using Amberlite IR 120, Purolite CT 175, Dowex Monosphere DR 2030 ve Dowex Monosphere M 31 at 120 °C and TBA/G=8/1 molar ratio. Quite high glycerol conversion and selectivity of di-ether values were obtained in very short residence times (18 g s cm-3) at the flow reactor. In the continuous flow system, the highest glycerol conversion (39%) was obtained with Dowex Monosphere DR 2030 and also the highest di-ether selectivity (0.22) was obtained with Amberlite IR 120 and Dowex Monosphere M 31. The experiment results have showed that the continuous flow system has more advantages than the batch system.