Fabric Softener Active Composition with Low Methanol Content
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Solution Overview
Problem
Existing fabric softener compositions containing tris-(2-hydroxyethyl)-methylammonium methylsulfate fatty acid esters have high methanol content, which is toxic and poses a workplace hazard, necessitating the development of compositions with low methanol levels and a simple method for their production.
Innovation Solution
Fabric softener active compositions comprising 65-98% tris-(2-hydroxyethyl)-methylammonium methylsulfate fatty acid esters with a total amine number of 7-20 mg KOH/g, achieved by reacting fatty acid esters of triethanolamine with dimethylsulfate at specific conditions to minimize methanol formation, resulting in a composition with 1-1500 ppm methanol.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If quaternization is carried out to achieve complete conversion of dimethylsulfate and high conversion of amine, then fabric softener active composition is produced, but high amounts of methanol are formed which is toxic and presents workplace hazard
Solution Approach 1:
The invention changes the reaction parameters by controlling the total amine number to be at least 5 mg KOH/g (preferably 7-20 mg KOH/g) and using a molar ratio of dimethylsulfate to amine nitrogen of 0.84 to 0.96. These parameter changes optimize the quaternization process to achieve complete dimethylsulfate conversion while minimizing methanol formation, resolving the contradiction between reliability and harmful factors.
Solution Approach 2:
The invention uses the total amine number as a feedback parameter to control the quaternization process. By monitoring and adjusting the total amine number during the reaction, the process ensures complete conversion of dimethylsulfate while maintaining low methanol content, as the total amine number directly correlates with the extent of reaction and methanol formation.
2Object-affected harmful factors
If higher total amine value is achieved at complete dimethylsulfate conversion, then low methanol content is obtained, but specific reaction conditions must be controlled
Solution Approach 1:
The invention defines specific parameter ranges for reaction control: total amine number of at least 5 mg KOH/g (preferably 7-20 mg KOH/g) and molar ratio of dimethylsulfate to amine nitrogen of 0.84 to 0.96. These parameter specifications provide clear guidance for achieving low methanol content while managing the complexity of reaction condition control through standardized ranges.
3Object-affected harmful factors
If fabric softener active composition with low methanol content is produced, then workplace safety is enhanced and labeling is simplified, but production method must be optimized
Solution Approach 1:
The invention optimizes the production method by specifying particular reaction parameters: total amine number of at least 5 mg KOH/g (preferably 7-20 mg KOH/g) and molar ratio of dimethylsulfate to amine nitrogen of 0.84 to 0.96. These parameter changes enable production of low methanol content compositions (at least 10 times lower than prior art) while maintaining ease of manufacture through well-defined process conditions.
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 solution reduces methanol content, enhancing workplace safety, simplifying product labeling and classification, and increasing the flash point of the composition while maintaining high fabric softening efficiency and processability.
Implementation Method 1
Quaternary ammonium salts carrying two hydrophobic long chain hydrocarbon moieties have found broad use as fabric softener actives
Data Source
AI summary
Reacting at least one tris-(2-hydroxyethyl)-amine fatty acid ester with dimethylsulfate at a molar ratio of dimethylsulfate to amine nitrogen of from 0.79 to 0.94 until the reaction mixture has a total amine number of from 7 to 20 mg KOH/g provides novel fabric softener active compositions with a low content of methanol, comprising from 65 to 98% by weight of tris-(2-hydroxyethyl)-methylammonium methylsulfate fatty acid esters and from 1 to 1500 ppm methanol.