Synthesis and characterization of copper-manganese, oxide octahedral molecular sieves, [3X3], [2x2] OMS, and rubidium-oms, with a [2x4] tunnel

Date of Publication

1998

Document Type

Dissertation

Degree Name

Doctor of Philosophy in Chemistry

Subject Categories

Chemistry

College

College of Science

Department/Unit

Chemistry

Thesis Adviser

Wyona C. Patalinghug

Defense Panel Chair

Jaime Raul O. Janairo

Defense Panel Member

Clovia Isabel Zayas Holdsworth
Gerardo C. Janairo
Anamy Ma. C. Paano
Consolacion Y. Ragasa

Abstract/Summary

A series of [3x3] manganese oxide octahedral molecular sieves (OMS-1) with copper incorporated in their structures were prepared by hydrothermal synthesis at 160 degrees Centigrade for 8 h. Another series of IMS with [2x2] tunnel structure containing copper was prepared by reflux method. The effects of Cu uptake on the structure, thermal stability, conductivity, electrochemical properties and catalytic activity were investigated. XRD, XPS studies, average oxidation state determination, ICP analyses, EPR, TGA and DSC measurements suggest that Cu2+ substitution in the framework of OMS-1 is possible at high concentration of the cation species in the interlayer sites of OL-1 in the course of its transformation to the tunnel material under hydrothermal conditions. Cyclic voltammetric studies of Cu-OMS-modified indium tin oxide electrodes suggest that the Cu2+ ions in the tunnels are mobile and electroactive. Catalytic evaluation of Cu-containing OMS materials shows a 16 percent and 50 percent conversion for the oxidative dehydrogenation of ethylbenzene to styrene at 300 degrees Centigrade, 1 atm using Cu-OMS-1 C with 13.67 percent Cu.Bulk synthesis of a [2x4] tunnel material using KMnO4,Mn2+, and RbOH by hydrothermal synthesis at 210 degrees Centigrade yielded a thermally stable material at 850 degrees Centigrade in oxygeb stream. Scanning electron micrographs of the rubidium manganese oxide revealed needle-like structures typical of a tunnel material.

Abstract Format

html

Language

English

Format

Print

Accession Number

TG02790

Shelf Location

Archives, The Learning Commons, 12F Henry Sy Sr. Hall

Physical Description

137 leaves

Keywords

Copper; Manganese oxides; Rubidium; Thermal analysis; Analytical chemistry

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