QD197 : Preparation and characterization of Molybdenum complex supported on nano-boehmit Functionalized with tri-methoxy silyl propyl chloride and Investigation of its catalytic application
Thesis > Central Library of Shahrood University > Chemistry > MSc > 2013
Authors:
Abdollah Feyzi [Author], Bahram Bahramian[Supervisor], Mahdi Mirzaee[Supervisor]
Abstarct: Supported mextal complexes as heterogeneous catalyst have been used extensively for a wide variety of applications. In these systems, the most important phenomenon is the catalyst elucidation from the support which will be overcome by use of covalent bonding of mextal complexes to the functionalized support. In this research, nano-boehmite with high surface area (326m2/g) and high degree of surface hydroxyl groups, was prepared via hydrothermal assisted sol-gel processing of aluminum 2-butoxide. Then it was covalently functionalized with 3-(tri-methoxysilyl)propyl chloride (CFNB). The terminal chloride group of CFNB then was replaced by imidazole (IFNB)). Then molybdenum-oxo-acetylacetonate supported on IFNB. ICP analysis showed that molybdenum loaded on IFNB was 0.32 mmol/g. XRD experiment confirmed the retention of the nano-boehmite structure after functionalizing and mextal supporting procedures. These supported catalysts were used in epoxidation of cis-cyclooctene and yields of products were investigated by GC. The catalytic procedure for both catalyst were optimized for different parameters such as amount of catalyst, solvent, oxidant, temperature and time. It was found that the optimized conditions with over 95% yield for epoxidation of cis-cyclooctene with these heterogeneous nano-catalysts were 15mg of catalyst, 1ml CCl4 as solvent, and 1.12 mmol t-butyl-hydro-peroxide as oxidant at 85ºC. The differences between these nano-catalysts were arisen on total time of catalytic process. The maximum yields were obtained after 60min, for Mo-IFNB. In addition, recycling experiments revealed that these nano-catalysts could be repeatedly applied for nearly complete epoxidation of alkenes for at least five successive cycles. On the other hand, among these catalysts, Mo-IFNB can be chosen as the best because it was yielded the maximum efficiency in shorter period of time which is a crucial factor in scaling up the process to pilot plant.
Keywords:
#Heterogeneous catalyst #nano-boehmite #sol-gel #epoxidation #cyclooctene Link
Keeping place: Central Library of Shahrood University
Visitor: