Polyaspartic Acid Precondensation for Stirring and Catalyst Recovery
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Solution Overview
Problem
The production of polyaspartic acid through acid-catalyzed thermal polycondensation of aspartic acid faces challenges with viscous and hard condensation phases that are difficult to stir, leading to caking issues and requiring interruption of the process for mechanical comminution, which complicates the purification and recovery of the catalyst.
Innovation Solution
A process involving precondensation of aspartic acid to a degree of conversion of at least 2% before adding an acidic catalyst, allowing for complete polycondensation and subsequent hydrolysis to produce polyaspartic acid, which avoids the formation of viscous condensation phases and facilitates continuous processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of substance
If small amounts of acidic catalyst (1 to 25 mol%) are used in polycondensation, then cost is reduced and catalyst recovery is simplified, but highly viscous to very hard condensation phases occur that cannot be stirred or kneaded
Solution Approach 1:
The invention applies preliminary action by conducting a precondensation step before the main polycondensation. During this precondensation, aspartic acid is heated to form a precondensate with at least 2% conversion to polyaspartimide. This preformed polyaspartimide then acts as a processing aid in the subsequent catalyzed polycondensation, preventing the formation of viscous, hard condensation phases that would otherwise be difficult to stir or knead. The preliminary formation of polyaspartimide modifies the reaction mass properties before the catalyst is added, enabling continuous processing with small catalyst amounts.
2Ease of operation
If the polycondensation process is interrupted to break up and comminute clumped solid polycondensate, then mixing is restored, but productivity is reduced and process complexity increases
Solution Approach 1:
The precondensation step creates a reaction mass that is pre-adapted for subsequent catalyzed polycondensation. The polyaspartimide formed during precondensation serves as a processing aid that prevents clumping and maintains stirrability throughout the main reaction, eliminating the need for interruptions to break up solid aggregates.
Solution Approach 2:
The invention enables continuous polycondensation by preventing the formation of hard, clumped phases that would require process interruption. The precondensate, when combined with the acidic catalyst, maintains a workable consistency throughout the entire polycondensation period, allowing continuous stirring and uninterrupted reaction progression to high molecular weights.
3Manufacturing precision
If phosphoric acid is used as both catalyst and solvent in well-controlled polycondensation, then product quality is improved, but complex purification and recovery processes are required
Solution Approach 1:
The invention changes the catalyst quantity parameter from the conventional large amounts (where phosphoric acid serves as solvent) to small amounts (1 to 25 mol%). This parameter change, combined with the precondensation step, achieves well-controlled polycondensation and high product quality without requiring the catalyst to serve as solvent, thereby simplifying purification and recovery processes.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach prevents the formation of hard, stirrable condensation phases, enabling continuous polycondensation and simplifying the recovery of the acidic catalyst, resulting in a more efficient and controlled production of polyaspartic acid.
Implementation Method 1
Precondensation of aspartic acid at a temperature of 100 to 250 °C to a degree of conversion of at least 2%
Implementation Method 2
addition of 1 to 25 mol% of an acidic catalyst; polycondensation of the reaction mass according to (c) at 170 to 250 °C
Implementation Method 3
hydrolysis of the polycondensates according to (d) with the addition of a base
Data Source
AI summary
The invention relates to a method for producing a polyaspartic acid by means of an aspartic acid precondensate and a polyaspartic imide precondensate, to compositions containing the thus obtained polyasparatic acid and to the use of said type of precondensate for producing polyaspartic acid.