Quaternization with Solid Acid Scavenger to Reduce Methanol
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Solution Overview
Problem
Tris-(2-hydroxyethyl)-methylammonium methylsulfate fatty acid ester fabric softener compositions contain unexpectedly high amounts of methanol, which is toxic and poses a workplace hazard, necessitating a method to produce compositions with low methanol content.
Innovation Solution
Quaternizing fatty acid esters of triethanolamine with dimethylsulfate in the presence of a solid acid scavenger, such as sodium carbonate, to minimize methanol production while achieving high conversion rates, resulting in a composition with reduced methanol content and low total amine number.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If quaternizing is carried out without acid scavenger to achieve complete conversion of dimethylsulfate, then high conversion of amine is achieved, but high amounts of methanol are formed
Solution Approach 1:
An acid scavenger is introduced as an intermediary substance to neutralize the acid byproduct formed during quaternization. The acid scavenger reacts with the acid to form a salt, preventing the acid-catalyzed formation of methanol while allowing the quaternization reaction to proceed to completion. This resolves the contradiction by adding a mediating component that eliminates the harmful effect without interfering with the main reaction.
2Object-generated harmful factors
If acid scavenger is added to reduce methanol formation, then methanol content is reduced, but reaction mixture complexity increases
Solution Approach 1:
The invention changes the chemical environment parameter by introducing an acid scavenger that modifies the pH and acid concentration in the reaction mixture. This parameter change suppresses the side reaction leading to methanol formation while maintaining the main quaternization reaction. The complexity increase is minimal as it only requires adding one chemical component and monitoring its consumption.
3Productivity
If quaternizing is carried out to achieve complete conversion, then fabric softener active composition is produced, but toxic methanol remains in the composition
Solution Approach 1:
The invention converts the harmful acid byproduct into a beneficial component by having it react with the acid scavenger to form a salt. This salt can remain in the final composition without harm, potentially providing additional functional benefits. The original harmful acid that would catalyze methanol formation is transformed into a harmless or even useful component, eliminating the workplace hazard while maintaining production efficiency.
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 effectively reduces methanol content in tris-(2-hydroxyethyl)-methylammonium methylsulfate fatty acid ester compositions, enhancing workplace safety, reducing labeling and classification requirements, and increasing the flash point, while maintaining high fabric softening efficiency.
Implementation Method 1
The term acid scavenger denotes a material which reacts with a Brönsted acid that is present in the quaternization reaction mixture or that is formed during quaternization
Data Source
AI summary
In a method for making a tris-(2-hydroxyethyl)-methylammonium methylsulfate fatty acid ester by quaternizing a tris-(2-hydroxyethyl)-amine fatty acid ester with dimethylsulfate the quaternizing is carried out in the presence of a solid acid scavenger. The method can provide a fabric softener active composition, comprising from 65 to 98 % by weight of at least one tris-(2-hydroxyethyl)-methylammonium methylsulfate fatty acid ester, the corresponding non-quaternized tris-(2-hydroxyethyl)-amine fatty acid esters in amounts providing a total amine number of the composition of from 2 to less than 7 mg KOH/g, and from 1 to 1500 ppm methanol.