3424.     ---------------.  [TRAMBOUZE, Y.]  [Relation of the Chemical Composition and Structure of Fischer Catalysts to Their Synthesis Activity.]  Thesis, Univ. Lyon, France, 1950, 87 pp.

        Previous discussions on the origin, structure, and reaction mechanism of the Fischer synthesis catalysts are reviewed.  The paper consists of 2 parts.  The 1^st discusses the chemical changes that occur in the development of Ni base catalysts.  The presence of the oxide and hydroxide of Ni, basic carbonates and hydroaluminate and -silicate of Ni was detected.  These were measured by a polarographic method.  The relative proportions of these various types of compounds can be changed markedly by changing the conditions of the thermal treatment preceding the reduction.  For example, reheating for 48 hr. at 220° in a stream of N₂ strongly diminishes the content of silicate and may even prevent its formation totally.  The 2d part discusses the effect of various chemical compositions on the catalytic activity of Fischer-Tropsch catalysts.  The specific role of each individual compound mentioned above, and particularly those of Ni hydrosilicate and Ni hydroaluminate, are discussed, the latter being found particularly important.