Patent GB-796175-A (GB)
Title: Improvements in or relating to catalysts and the production thereof
IPC: B01J23/88
Filed: 1955-09-21
Abstract: Metal chelates in which the chelating agent is an amino acid are formed by reacting in an aqueous medium an amino acid and a compound of the metal, e.g. the hydroxide, carbonate metal-halogen acid or sulphate.  The following amino acids are specified: ethylene diamine tetra-acetic acid, N-2-hydroxyethyl ethylene diamine triacetic acid, aspartic acid, glutamic acid, tryptophan, valine, phenylalamine, alpha-alamine, beta-alamine, and asparagine.  When a polycarboxylic amino acid is used, the chelate may have hydrogen atoms which are replaceable by a metal different from that already present.  Metals referred to are platinum, nickel, cobalt, iron, molybdenum, chromium, zinc, calcium, magnesium and barium.  Ammonium hydroxide may be added to the aqueous medium in which the reaction takes place, the ammonium radical being present in the chelate compound formed. Preparations of various metal chelates are described in examples, including the preparation of a platinum chelate containing chlorine atoms, and a process for removing the chlorine atoms. The metal chelates are used as solutions or dispersions for impregnation of porous supports in the preparation of catalyst (see Group III).ALSO:A catalyst is prepared by wetting a porous support, having a surface area of at least 25 square metres per gram, with a solution or dispersion of a chelate formed from a metal and an amino acid, and drying and calcining the wetted support to decompose the amino acid.  Metal chelates may be formed from the following amino acids: ethylenediamine tetra-acetic acid (EDTA), N-2-hydroxyethyl ethylenediamine triacetic acid, aspartic acid, glutamic acid, tryptophan, valine, phenylalanine, alphaalanine, beta-alanine, and asparagine.  When a polycarboxylic amino acid is used, the chelate may have replaceable hydrogen atoms; these hydrogen atoms may be replaced by a metal which may be different from that in the cation, the resulting salts being used to impregnate the support with two metals simultaneously, e.g. molybdenum and cobalt, cobalt and chromium, zinc and chromium, nickel and chromium.  The support may be dried before impregnation or may be in the form of a wet or freshly precipitated gel. After impregnation, drying removes the solvent and calcining decomposes the chelate to the metal or metal oxide which may be reduced or converted to a sulphide or halide.  The support may have cracking activity, examples being silica-alumina, silica-magnesia, silica-alumina-zirconia, and clay products.  In examples: (1) silica-alumina beads are impregnated with a solution of ammonium molybdate and a chelate compound formed from cobalt and EDTA; (2) alumina is impregnated with a solution of molybdenum trioxide in aqueous oxalic acid, dried, calcined and then impregnated with a solution of the cobalt-EDTA compound; (3) silica-alumina is impregnated twice with solutions containing cobalt and molybdenum as in (1); (4) silica-alumina is impregnated with a solution of the cobalt-EDTA compound and the resulting catalyst found to have a longer life in cracking gas oil than a catalyst prepared using an impregnating solution of cobalt nitrate; (5)-(7) silica-alumina is impregnated with a solution of a chelate compound of cobalt and aspartic acid, glutamic acid, or tryptophan; (8)-(10) silica-alumina is impregnated with a solution of a chelate compound of iron and EDTA, valine, or phenylalanine; (11)-(13) silica-alumina is impregnated with a solution of a chelate compound of nickel and EDTA, alphaalanine, or beta-alanine; (14) alumina is impregnated with an ammoniacal solution of a chelate compound of platinum and EDTA containing chlorine; (15) silica-alumina is impregnated with an ammoniacal solution of a chelate compound of platinum and EDTA free from chlorine; (16) silica-alumina containing cobalt and chromium is prepared by impregnating the support with a solution of cobalt-EDTA-chromate; (17) silica-alumina containing zinc and chromium is prepared by impregnating the support with a solution of zinc-EDTA-chromate; (18) silica-alumina is impregnated with a solution of a cobalt salt of an acid nickel chelate formed from nickel and EDTA; (19) silicon-alumina is impregnated with a solution of a nickel salt of an acid nickel chelate as in (18); (20) silica-alumina is impregnated with a solution of a chelate compound of nickel and asperagine; (21) silica-alumina is impregnated with a solution of a cobalt salt of an acid platinum chelate formed from platinum and EDTA; (22) silica-alumina is impregnated with a solution of a nickel salt of acid ferric chelate formed from iron and EDTA; (23) silica-alumina is impregnated with calcium, magnesium, or barium salts of acid chelates formed from EDTA and iron, platinum, cobalt, or chromium. The catalysts may be used in processes of hydrogenation, dehydrogenation, cracking and hydrocracking, isomerization, reforming, aromatization, cyclization, oxidation, desulphurization, denitrogenation, and disproportionation.