GLDA Chelating Composition Viscosity and Corrosion Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The high viscosity of concentrated solutions of tetrasodium salt of glutamic acid N,N-diacetic acid (GLDA) limits practical concentrations and causes handling difficulties, and the corrosive nature of aqueous GLDA solutions due to free caustic by-products restricts their application, especially in large-scale productions involving aluminum components.
Innovation Solution
A method involving combining monosodium glutamate and/or glutamic acid with formaldehyde, followed by hydrogen cyanide addition at controlled temperatures and pH, converting nitrile groups to carboxylate groups to form a chelating composition with a high weight percent of tetrasodium salt of glutamic acid N,N-diacetic acid, achieving low viscosity and reduced corrosiveness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the concentration of GLDA tetrasodium salt is increased, then the productivity and efficiency improve, but the viscosity increases making the solution difficult to handle
Solution Approach 1:
The patent changes the chemical composition parameters by introducing specific co-solvents (ethylene glycol, propylene glycol, or their esters) in controlled amounts (0.1-10 wt%) to modify the viscosity-concentration relationship. This allows achieving higher GLDA concentrations (50-70 wt%) while maintaining acceptable viscosity levels for handling
Solution Approach 2:
The patent creates a composite chelating composition by combining GLDA tetrasodium salt with specific co-solvents to form a new compositional system. This composite approach leverages the solvating properties of glycols to reduce intermolecular interactions between GLDA molecules, thereby reducing viscosity at high concentrations
2Quantity of substance
If the concentration of GLDA tetrasodium salt is increased, then the chelating efficiency improves, but the solution becomes a paste requiring heating
Solution Approach 1:
The patent modifies the physical state parameters by adding co-solvents that lower the freezing point and reduce the glass transition temperature of the system. This prevents the formation of paste-like structures even at high concentrations and ambient temperatures, eliminating the need for heating containers
3Reliability
If free caustic is present in the GLDA solution, then the chelating capacity is maintained, but the corrosiveness to aluminum increases
Solution Approach 1:
The patent introduces co-solvents as intermediary substances that modify the chemical environment. These co-solvents interact with free caustic to reduce its reactivity toward aluminum while maintaining the overall chelating capacity of the GLDA solution. The co-solvents act as a buffer system that mitigates the harmful corrosive effects
4Reliability
If the pH is maintained at high levels for chelating performance, then the metal sequestration improves, but the corrosiveness to aluminum components increases
Solution Approach 1:
The patent changes the pH-modifying approach by using co-solvents that allow maintaining high pH (9-11) without proportionally increasing free caustic content. The co-solvents alter the pH-conductivity-corrosiveness relationship, enabling high chelating performance at reduced corrosiveness levels
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
The method produces a chelating composition with a viscosity of less than 1350 mPa.s and a pH of at least 9, allowing for higher concentrations of GLDA without becoming a paste, and reduces corrosiveness, enabling easier handling and broader application, including in aluminum-containing systems.
Implementation Method 1
converting nitrile groups of the monosodium salt of glutamic acid diacetonitrile to carboxylate groups thereby forming a third combination comprising water and at least about 47 weight percent of the tetrasodium salt of glutamic acid N,N-diacetic acid
Implementation Method 2
maintaining a temperature of the second combination at less than about 16°C and a pH of less than about 7
Data Source
Figure 1
AI summary
A method includes combining monosodium glutamate and/or glutamic acid with formaldehyde to form a first combination; adding hydrogen cyanide to form a second combination comprising a monosodium salt of glutamic acid diacetonitrile, a cyclic GLMN, and a sodium salt of glutamic acid N- mono acetonitrile, maintaining a temperature of the second combination at less than about 16°C and a pH of less than about 7; converting nitrile groups to carboxylate groups thereby forming a chelating composition comprising water and at least about 47 weight percent of the tetrasodium salt of GLDA, wherein a reaction yield is at least about 91%.