Patent ID: 6514473
Filing Date: 2003-02-04
Classification: A61K,A61Q,B01J,C01B,C01F,C01G,C01P,C08K

Abstract:
A process for producing high purity hydrotalcites which are stratiform, anionic mixed metal hydroxides of the general formulaM2x2+M23+(OH)4Ã—+4Â·A2/nnâˆ’Â·zH2O wherein M2x2+, M23+ are divalent and trivalent metal(s) respectively, ranges from 0.5 to 10 in intervals of 0.5, A is an inorganic interstitial anion, n is the charge of said interstitial anion, and z is an integer of 1to 6, comprising(A) mixing at least one divalent metal alcoholate with at least one trivalent metal alcoholate, both metal alcoholates being metal alcoholates of mono-, di-, or trihydric C1 to C40 alcoholates, where said mono-, di- and trihydric metal alcoholates are used in a molar ratio about corresponding to the stoichiometry of the general formula referred to hereinabove, and where the production of said metal alcoholates is selected from the group consisting of (i) placing metals jointly into a reaction vessel and then adding an alcohol, (ii) producing the metal alcoholates from metals and at least one alcohol in separate preparations and then combining the alcoholates, where the alcoholates have the same or different alcoholate residues, and (iii) consecutively, by placing a first metal into a reaction vessel, adding an alcohol, followed by addition of a second metal (B) separating any insoluble component prior to hydrolysis, where the insoluble component is insoluble in a material selected from the group consisting of C5- to C20-alcohols and metal alcoholates of C5- to C20-alcohols, and (C) hydrolyzing the resultant alcoholate mixture from (B) with a stoichiometric excess of water for hydrolysis, relative to the reactive valences of the metals, and where the source of the interstitial anions for A is selected from the group consisting of water-soulble anions contained in the water for hydrolysis. 2.The process according to claim 1 wherein the divalent metals are selected from the group consisting of Mg, Zn, Cu, Ni, Co, Mn, Ca and Fe and the trivalent metals are selected from the group consisting of Al, Fe, Co, Mn, La, Ce and Cr.