METHOD OF PRODUCING SALT SOLUTION OF DIBASIC ACIDS AND DIAMINES Russian patent published in 2013 - IPC C08G69/28 C07C51/41 C07C209/68 C07C55/02 C08L77/06 C08G69/26 

FIELD: chemistry.

SUBSTANCE: invention relates to an improved method of producing a salt solution of dibasic acids and at least one diamine for producing a polyamide. The method of producing an aqueous solution (A) of salts of dibasic acids and at least one diamine is realised by mixing at least two dibasic acids and at least one diamine, with mass concentration of the salt in the range of 40-70%, wherein the method includes the following steps of: obtaining, in a reactor, an aqueous solution (A') of at least one diamine and at least dibasic acid, wherein molar ratio dibasic acid/diamine is less than 1 and preferably less than or equal to 0.9; feeding into said reactor, in which there is a liquid containing water and diamine at temperature ranging from 55 to 95°C (inclusively) and preferably ranging from 60 to 90°C (inclusively), a stream (B') which contains a dibasic acid, optionally a stream which contains diamine and optionally a stream which contains water; wherein the flow rate of one or more of the fed streams is controlled in order constantly keep temperature of the solution in the reactor below boiling point at the given operating pressure therein; wherein the amount of water and diamine in the liquid component, as well as the flow rate of the fed streams is controlled in order to constantly keep molar ratio of the dibasic acids/diamines less than 1; wherein the dibasic acid in stream (B') is an aliphatic or cycloaliphatic dibasic acid in which the number of carbon atoms is greater than 10, or an aromatic dibasic acid; and the aqueous solution (A'), coming from the fist step, is mixed with stream (B"), which contains at least one dibasic acid, wherein the dibasic acid is an aliphatic or cycloaliphatic dibasic acid in which the number of carbon atoms is less than or equal to 10, and optionally an additional amount of water and/or diamine to obtain an aqueous solution (formed by a mixture of (A') and (B")), in which the molar ratio dibasic acids/diamines ranges from 0.9 to 1.1 and preferably from 0.98 to 1.02 (inclusively); wherein said solution is heated to temperature not higher than the boiling point of the solution at operating pressure at least through release of heat of reaction between at least one diamine and dibasic acids; wherein said operations are carried out to obtain a solution (A) of dibasic acids and at least one diamine with the required concentration and composition.

EFFECT: method enables to obtain homogeneous solutions which can be used directly in a polymerisation apparatus or taken for storage.

8 cl, 5 ex, 2 dwg