AUTHOR=Alsawalha Murad 

TITLE=Catalytic Activity and Kinetic Modeling of Various Modules HZMS-5 and Treated MCM-41 Catalysts, for the Liquid-Phase Ketalization of Glycerol With Acetone

JOURNAL=Frontiers in Chemistry

VOLUME=Volume 7 - 2019

YEAR=2019

URL=https://www.frontiersin.org/journals/chemistry/articles/10.3389/fchem.2019.00799

DOI=10.3389/fchem.2019.00799

ISSN=2296-2646

ABSTRACT=Studies of the Ketalization reaction using trivalent alcohol glycerol in combination with acetone and their kinetics modeling are still limited. The focus of this current study is an investigation into HZSM-5 with various silica to alumina molar ratios (M= 35, 90 and 160) for the reaction between glycerol and acetone. In addition, the influence of reaction temperatures (25 °C, 50 °C and 60 °C) on the rate of the reaction have also been considered. Additionally, this investigation established the rate law for all HZMS-5 models (M = 35, 90 and 160) which showed ‘’n’’ order equals half while the activation energy was found to be 164.34 kJ mol-1 with a constant reaction rate of k0=5.2678*1028 (Concentration½. min-1). Furthermore, MCM-41 pure mesoporous materials were separately treated using various methods. The first involved treatment using Dichlorodimethylsilane MCM 41(TD) and later treatment of a pure sample with sulfuric acid MCM-41. The sulfated MCM-41 sample (MCM41-SU) showed that reaction order equals n=-1 and a rate constant of (k) =3.9x 102 (Concentration-2. min-1). Additionally, this current kinetic study showed that water production has no effect on the conversion activity within ten minutes from the start of reaction. Besides, further kinetics investigations were performed to ascertain the estimated time for water production based on the conditions applied during the reaction system. It resulted in an average time of three minutes for equilibrium to be reached in the reaction system. It was found that the estimated reaction equilibrium time (teq) is within the range from zero to ten minutes in agreement with the proposed kinetic model in this work. At a reaction temperature of 60 °C (333.15 K) and at one atmosphere, the acetone was shown to exert a vapour pressure of about 113.737 mm Hg. Hence, the overall order of the reaction was determined by the method of initial rates. Similarly, in order to ascertain the dispersion of aluminum,  a mathematical approach is proposed in this study for its calculation.