Method for preparing hydrotalcite

Abstract

The invention discloses a method for preparing hydrotalcite, which comprises the following steps: adding a reaction material mixed alkali solution (containing OH<->and CO3<2->) into a reaction systemin a dispersive dropwise adding manner to react, thereby obtaining a hydrotalcite raw material with excellent acid production capacity, and keeping the pH value between 3 and 5 for a long time. When the prepared preparation product is used for treating hyperacidity, the excellent performance of generating a lasting anti-acid clinical curative effect is shown. And the preparation method is simple to operate, high in yield and suitable for industrial large-scale production.

Description

technical field [0001] The invention belongs to the fields of organic chemistry, inorganic chemistry and medicinal chemistry, and in particular relates to a method for preparing aluminum magnesium carbonate. Background technique [0002] Aluminum magnesium carbonate has the molecular formula Al 2 Mg 6 (OH) 16 CO 3 4H 2 O, molecular weight 604, white or off-white granular powder, almost insoluble in water, dissolved in dilute hydrochloric acid accompanied by bubbles. It is clinically used to treat duodenal ulcer, acute and chronic gastritis, bile reflux esophagitis, and gastric discomfort related to excessive gastric acid secretion. [0003] Aluminum magnesium carbonate is a kind of aluminum magnesium hydrotalcite, and the general structural formula of aluminum magnesium hydrotalcite is Al a Mg b (OH) c XCO 3 ·YH 2 O, its preparation principle is to contain Al 3+ Aluminum salts and Mg-containing 2+ The magnesium salt is obtained by co-precipitation in an alkalin...

AI Technical Summary

Problems solved by technology

[0014] However, the above-mentioned disclosed preparation methods all have their disadvantages, for example, the water-insoluble substance magnesium oxide is used as Mg in method one. 2+ The source of magnesium oxide is insoluble in water, so there will be incompletely reacted magnesium oxide existing in the target product in the form of impurities, and it will have a certain degree of influence on the acid-making ability

Whereas method 1 uses carbonate hydrolysis to provide OH - , but from the molecular formula Al of aluminum magnesium carbonate 2 Mg 6 (OH) 16 CO 3 4H 2 It can be seen that the number of hydroxide radicals of O is 16, relying only on the OH provided by the hydrolysis of carbonate - It is difficult to meet the needs of the reaction itself, which leads to the number of hydroxides in the aluminum-magnesium hydrotalcite structure prepared by method 1 being less than 16, 14, or even less, and the final result is the aluminum-magnesium hydrotalcite prepared by method 1. The anti-acid time of hydrotalcite products is too short (keep the pH between 3 and 5 for only 60 minutes or less)

And for method 2, it can be said that it is the most mature method to prepare aluminum magnesium carbonate with lasting acid-making power at present, but, in the existing published literature, all adopt mixed salt solution and mixed alkali solution to directly mix and react, the result is due to the reaction system The local alkalinity is too strong (pH reaches more than 14), and the obtained aluminum magnesium carbonate presents a colloidal state, which cannot be followed by washing (because of the excessive OH in the system must be removed by a large amount of water washing in the pharmaceutical aluminum magnesium carbonate post-treatment process). - , CO 3 2- ) and solid-liquid separation, even by prolonging the aging time (making the solid particles as large as possible) as mentioned in the literature, the actual experimental effect is still very limited

Therefore, although method 2 can obtain aluminum magnesium carbonate samples with lasting acid-making ability to a certain extent, it cannot realize industrial scale-up production

[0015] Problems in the prior art, the inventor has gone through a lot of research, such as, at first the inventor has also tried to adopt other conventional ways to solve the colloidal form that occurs in method 2, as first allowing a part of the mixed salt solution and a part Carbonate reaction, then add the remaining mixed salt solution and mixed alkali solution; another example is to increase the stirring rate of the reactor; another example is to further extend the aging time (24h or even longer), but there is no solution

Images