Alkyl Ether Sulfate Composition for Low-Dioxane Sulfation
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Solution Overview
Problem
Existing alkyl ethoxy sulfate (AES) surfactants generate dioxane during sulfation and processing, making it difficult to comply with regulatory limits of 10 ppm or less, and traditional stripping methods are costly and ineffective over time.
Innovation Solution
Forming alcohol ethoxylates with 95 mol% having a single ethylene-oxide unit and 5 mol% or less with 2 or greater units, using a metallosilicate catalyst to produce surfactants that resist dioxane formation up to 280°C.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If traditional stripping techniques are used to remove dioxane from sulfated surfactants, then dioxane concentrations can be reduced below regulatory thresholds, but the process becomes expensive and time-consuming
Solution Approach 1:
The patent applies preliminary action by controlling the ethylene oxide distribution during the alcohol ethoxylate production stage to prevent dioxane formation in the first place. By ensuring 95 mol% or greater has n=1 and 5 mol% or less has n≥2, the surfactant is pre-configured to resist dioxane formation during subsequent sulfation and processing, eliminating the need for costly stripping operations later
Solution Approach 2:
The patent changes the critical parameter of ethylene oxide unit distribution in alcohol ethoxylates. By specifying that 95 mol% or greater must have a single ethylene oxide unit (n=1) and 5 mol% or less can have two or more units (n≥2), the chemical structure is optimized to prevent dioxane formation while maintaining surfactant performance
2Reliability
If alcohol ethoxylates with higher ethylene oxide content are used to improve surfactant performance, then surfactant effectiveness increases, but dioxane formation increases during sulfation and processing
Solution Approach 1:
The patent applies local quality by creating a specific distribution profile of ethylene oxide units rather than uniform composition. The majority (95 mol% or greater) has n=1 which provides good surfactant performance, while a small controlled portion (5 mol% or less) has n≥2. This localized differentiation optimizes both performance and dioxane resistance
Solution Approach 2:
The patent precisely controls the parameter of ethylene oxide unit number (n) distribution. By setting specific thresholds (95 mol% or greater with n=1, 5 mol% or less with n≥2), it optimizes the balance between surfactant performance and dioxane formation resistance during sulfation and high-temperature processing
3Productivity
If conventional alcohol ethoxylate distribution is used during sulfation, then production efficiency is maintained, but dioxane concentrations exceed regulatory limits
Solution Approach 1:
The patent implements preliminary action by pre-establishing the optimal ethylene oxide distribution (95 mol% or greater with n=1, 5 mol% or less with n≥2) before sulfation. This preliminary configuration ensures that during high-temperature sulfation and subsequent processing, dioxane formation is inherently limited, allowing efficient production while meeting regulatory requirements
Solution Approach 2:
The patent changes the parameter of ethylene oxide unit distribution to specific thresholds that simultaneously enable efficient production and limit dioxane formation. By requiring 95 mol% or greater to have n=1 and 5 mol% or less to have n≥2, the process achieves both productivity and compliance
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 surfactants maintain dioxane levels below 9 ppm during sulfation and exposure to elevated temperatures, ensuring compliance with regulatory standards without the need for costly stripping processes.
Implementation Method 1
contacting an olefin, an alcohol and a metallosilicate catalyst to form oligomers of an alcohol ethoxylate
Implementation Method 2
sulfating the oligomers of Structure (I) to form oligomers of Structure (II)
Data Source
AI summary
A process includes the steps of contacting an olefin, an alcohol and a metallosilicate catalyst to form oligomers of an alcohol ethoxylate having structure (I), wherein R1 is an alkyl, R2 is an alkyl, and n has a value of 1 to 3; and sulfating the oligomers of Structure (I) to form oligomers of Structure (II), wherein R1 is an alkyl, R2 is selected from the group consisting of an alkyl group, M is selected from the group consisting of a proton, an ammonium cation, a metal cation, a nitrogen cation, a boron cation, a phosphorus cation, triethylamine, triethanolamine, monoethanolamine and combinations thereof, and n has a value of 1 to 3, and wherein 95 mol % or greater of the oligomers of Structure (II) have an n of 1 and 5 mol % or less of the oligomers of Structure (II) have an n of 2 or greater.