Process for the preparation of tris(hydroxymethyl)-aminomethan-lactate-dihydroxyaluminate

A process for the production of tris(hydroxymethyl)-aminomethan-lactate-dihydroxyaluminate by the reaction of equimolar quantities of lactic acid, tris aminomethane and aluminum isopropylate.

The present invention relates to a method for producing 
tris(hydroxymethyl)-aminomethan-lactate dihydroxyaluminate, having an 
empirical formula of C.sub.7 H.sub.18 NO.sub.8 Al, a molecular weight of 
271.21, and having the following structural formula: 
##STR1## 
The compound obtained according to the process of the present invention has 
a very high activity as an antacid, particularly due to its high 
neutralizing capacity on a weight by weight basis. 
The process according to the present invention begins with the 
solubilization in water of lactic acid and with the subsequent addition of 
tris-hydroxymethyl aminomethane (THAM) and of aluminum isopropylate, said 
additions being capable of being effected indifferently in any sequence.

The present invention will be better understood by the following operative 
examples of the invention given purely by way of illustration and not of 
limitation. 
EXAMPLE 1 
In a 1 liter round-bottom flask, equipped with stirrer, reflux condenser 
and thermometer, there is dissolved 51 g of lactic acid (88%) (0.5 mol) in 
300 ml of water. 
To this solution there is added portion wise 102 g of aluminum isopropylate 
(0.5 mol). 
There results a fair ex-othermic reaction which raises the interior 
temperature of the flask to about 50.degree. C. 
The suspension is then heated, with stirring to 60.degree. C. for two 
hours. It is then cooled to 25.degree. C. 
There is thus obtained an opalescent solution to which there is added 60.5 
g of THAM (0.5 mol). The mixture is stirred at room temperature for one 
hour. 
The insoluble residue is then removed by filtration and the filtrate is 
concentrated under reduced pressure to a dry residue, keeping the bath 
temperature below 50.degree. C. 
The solid residue is then dried under reduced pressure to constant weight, 
at a temperature of 40.degree. C. 
There are obtained 133 g of the product of formula (I) that is, 
tris(hydroxymethyl)-aminomethan-lactate dihydroxyaluminate. 
EXAMPLE 2 
In a 3 liter round bottom flask, equipped with stirrer, reflux condenser 
and thermometer, there is dissolved 102 g of lactic acid (88%) (1 mol) in 
600 ml of water. 
To the flask there is then added 121 g of THAM (1 mol). After a solution is 
obtained, there is added 204 g of aluminum isopropylate (1 mol) dissolved 
in 1 liter of isopropyl alcohol. 
The mixture is then stirred for 2 hours at room temperature. 
The insoluble residue is filtered and the filtrate is concentrated under 
reduced pressure until a dry residue is obtained. 
Said residue is then removed from the flask and dried under reduced 
pressure in the presence of silica gel to constant weight. 
There are obtained 268 g of the product of formula (I) that is, 
tris(hydroxymethyl)-aminomethan-lactate dihydroxyaluminate. 
EXAMPLE 3 
In a 10 liter round bottom flask, equipped with stirrer, reflux condenser 
and thermometer, there is dissolved 510 g of lactic acid (88%) (5 mol) in 
3 liters of water. 
To the solution there is added 605 g of THAM (5 mol) and the resulting 
mixture is stirred for 30 minutes at room temperature. 
There is then added in small portions 1020 g (5 mol) of aluminum 
isopropylate. 
There is as a result a slight exothermic reaction (to about 35.degree. C.). 
The mixture is then heated for a period of 2 hours at 65.degree. C. until 
an opalescent solution is obtained. 
The product is isolated by removing the water by means of a spray-drying 
apparatus. 
There is obtained 1340 g of the product of formula (I), that is 
tris(hydroxymethyl)-aminomethan-lactate dihydroxyaluminate. 
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ANALYTICAL COMATIVE TABLE 
ANTACID 
ELEMENTAL ANALYSIS 
Example 
% H.sub.2 O 
Compl. 
PH ACTIVITY 
C H N 
No. (KF) 
Titer 
(5% sol.) 
ml HCl 0.1N 
Calc. 
Found 
Calc. 
Found 
Calc. 
Found 
__________________________________________________________________________ 
1 4.65 
99.6 
7.88 151 31.00 
30.64 
6.68 
6.96 
5.16 
4.99 
2 2.66 
98.2 
8.02 149 31.00 
31.21 
6.68 
6.59 
5.16 
5.07 
3 2.05 
99.1 
7.91 152 31.00 
30.75 
6.68 
6.44 
5.16 
4.98 
__________________________________________________________________________ 
For a better understanding of the invention there follows a description 
which illustrates how the antacid activity was determined. 
To a water glass having a capacity of 400 ml and maintained into a constant 
temperature bath of 37.degree. C., there is added 200 ml of 0.015 N HCl. 
When the liquid in the glass has reached the bath temperature of 37.degree. 
C., there is added thereto a quantity of the test sample equivalent to 2.3 
g of product, stirring with a glass rod to facilitate the solubilization 
of the powder. At 30 minutes after the addition of the powder, the pH of 
the solution is measured, verifying that said pH is between 5.0 and 6.5. 
There is then added, by means of a 50 ml burette, 0.1 N HCl at the rate of 
1 ml per minute, with slight agitation. The determination is considered 
finished when the pH of the solution has reached 3.0. 
While there have been given only few examples of the actuation of the 
process of the present invention, it is obvious to one skilled in the art 
that various modifications thereof can be effected without departing from 
the scope of the present invention and remaining in the ambit thereof.