United States Patent Office Patented Nov
3,539,306 United States Patent Office Patented Nov. 10, 1970 2 properties of quick activity, durable effect and storage 3,539,306 PROCESS FOR THE PREPARATION Stability, and that, therefore, the same can provide an ex OF HYDROTALCITE cellent, ideal antacid. Teruhiko Kumura and Norio Imataki, Takamatsu-shi, Hydrotalcite is known as a mineral having a chemical Katuyuki Hasui, Kagawa-ken, and Takeo Inoue and 5 Structure of the formula Kimiaki Yasutomi, Nagao-machi, Kagawa-ken, Japan, assignors to Kyowa Chemical Industry Co., Ltd., Tokyo, MgAl(OH) 16CO3 4HO O Al2O3 6MgO CO2: 12H2O Japan, a corporation of Japan No Drawing. Filed July 21, 1967, Ser. No. 654,977 which has been naturally produced in only very limited Claims priority, application Japan, July 25, 1966, areas as Norway and Ural. Also a process for the syn 41/48,349; July 17, 1967, 42/45,658 O thesis of hydrotalcite was disclosed, which comprises add Int. C. COf 5/00, 7/00, A61k 27/06 ing Dry Ice or ammonium carbonate to a mixture of U.S. C. 23-315 4 Claims magnesium oxide and y-alumina or the thermal decom position product from of magnesium nitrate and aluminum nitrate, and thereafter maintaining the system at tempera ABSTRACT OF THE DISCLOSURE, tures below 325 C. and under elevated pressures of total A process for the preparation of hydrotalcite which 2,000-20,000 p.s.i. (Roy et al.: American Journal of comprises mixing an alumium component such as alumi Science 251, 350-353 (1953)). However this process is num Salt With a magnesium component such as magnesium obviously unpractical for industrial scale production of Salt in an aqueous medium in the presence of carbonate hydrotalcite, because the reaction system must be main ion at a pH of at least 8 and thereafter recovering the 20 tained under considerably high pressures.
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