Young, Kay (1989) Mixed metal alkoxides as ascatalyst precursors. Doctoral thesis, Durham University.
This thesis describes research carried out to explore the use of mixed metal alkoxides as precursors of materials with catalytic activity in synthesis-gas chemistry. The alkoxide derived catalyst materials are compared against catalysts prepared by traditional co-precipitation methods. A discussion of the project objectives introduces the work and Chapter 1 includes a chronological survey of the literature up to the present day. A brief discussion of the commercial uses of alkoxides is given. Chapter 2 describes the general methods of synthesis and the properties of simple and bimetallic alkoxides; M(OR)(_x) and M[M'(OR)(_n)](_x) respectively. A more detailed treatment of the alkoxides of the first row transition elements is given, with emphasis on the properties and characteristics responsible for their possible potential as catalyst precursors. Chapter 3 deals with the catalytic aspects of ammonia and methanol synthesis. The preparation of industrial, heterogeneous catalysts has traditionally been carried out by co-precipitation of, for example, basic carbonates. The catalytic materials obtained may display catalytic activities which vary markedly (and not always controllably) with the precipitation, ageing, calcinations and/or reduction conditions employed. A discussion of the reaction mechanisms involved in ammonia and methanol syntheses is included. Several mixed metal alkoxides have been prepared from metals known to have catalytic activity in synthesis-gas chemistry (i.e. Mn, Fe, Co, Cu, Zn and Al). These metal alkoxides (e.g. Cu[Al(OPr(^1) (_4)](_2) ) have been characterised and found to compare well with literature data. Analyses, Infra-red and Mass-spectra are reported. After conversion to catalytic materials the alkoxide derived compounds were examined for surface properties ( oxide phases present, copper surface area, crystallite size, pore size distributions and pore volumes). The alkoxide materials compared quite well with the precipitated analogues and there was a difference in the properties of materials derived from different alkoxy groups. These studies were limited to the copper-aluminium alkoxides. The formation of a nickel (II) chloride, HMPA adduct is reported.
|Item Type:||Thesis (Doctoral)|
|Award:||Doctor of Philosophy|
|Copyright:||Copyright of this thesis is held by the author|
|Deposited On:||08 Feb 2013 13:39|