N-Vinyl Carboxylic Acid Amide Monomer Purification via Solvent Crystallization
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Solution Overview
Problem
Existing methods for producing N-vinyl carboxylic acid amide monomers face challenges in efficiently purifying the monomer and achieving high polymerizability, leading to low productivity and high costs.
Innovation Solution
A method combining cooling crystallization with solvent crystallization using toluene and an aliphatic hydrocarbon with 6 to 7 carbon atoms is employed to produce a highly polymerizable N-vinyl carboxylic acid amide monomer, involving melting, cooling, solid-liquid separation, and subsequent solvent crystallization to achieve high purity and polymerizability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If pressure crystallization is used to purify N-vinyl carboxylic acid amide, then high polymerizability is achieved, but equipment investment is large and production cost is high
Solution Approach 1:
The invention changes the crystallization parameters by using a specific solvent system (alcohol and aliphatic hydrocarbon) with controlled temperature gradients. By adjusting the solvent composition ratios and temperature profiles during crystallization, the method achieves high polymerizability without requiring expensive pressure crystallization equipment, thus resolving the contradiction between reliability and ease of manufacture.
Solution Approach 2:
The invention introduces a specific solvent system as an intermediary medium to facilitate purification. The solvent system acts as a mediator that enables crystallization under ambient pressure conditions, replacing the need for expensive pressure crystallization equipment while maintaining high polymerizability of the product.
2Manufacturing precision
If solvent crystallization with alcohol and aliphatic hydrocarbon is used, then purification is achieved, but large amount of poor solvent is required and volumetric efficiency is low
Solution Approach 1:
The invention optimizes the solvent system parameters by selecting specific alcohol types (methanol, ethanol, propanol, or butanol) and controlling their ratios with aliphatic hydrocarbons. By adjusting these parameters, the method achieves effective purification with reduced solvent用量, thereby improving volumetric efficiency while maintaining high purity.
Solution Approach 2:
The invention applies local quality by using different types of solvents with specific properties in different stages of the crystallization process. The alcohol component provides selective dissolution while the aliphatic hydrocarbon component controls precipitation, achieving efficient purification with optimized solvent usage.
3Ease of manufacture
If conventional purification methods are used, then production process is simple, but polymerizability is insufficient
Solution Approach 1:
The invention merges cooling crystallization and solvent crystallization into a single integrated process. By combining these two crystallization methods, the invention achieves both high polymerizability and process simplicity, as the unified process eliminates the need for separate purification steps while maintaining effective removal of inhibitors.
Solution Approach 2:
The invention segments the crystallization process into distinct stages: cooling crystallization for initial precipitation and solvent crystallization for refined purification. This segmentation allows each stage to perform its specific function effectively, achieving high polymerizability while keeping the overall process simple and efficient.
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 method significantly enhances the productivity of highly polymerizable N-vinyl carboxylic acid amide monomers, achieving high purity and excellent polymerizability, thereby reducing production costs and improving industrial scalability.
Implementation Method 1
melting a crude N-vinyl carboxylic acid amide monomer comprising 50 to 88 mass % of an N-vinyl carboxylic acid amide monomer by heating, followed by cooling for precipitation (cooling crystallization)
Implementation Method 2
cooling for precipitation (cooling crystallization), and subjecting precipitated N-vinyl carboxylic acid amide monomer crystals to solid-liquid separation
Implementation Method 3
further dissolving the N-vinyl carboxylic acid amide monomer crystals separated in the step (A) in a mixed solvent of toluene and an aliphatic hydrocarbon having 6 to 7 carbon atoms, then performing crystallization (solvent crystallization)
Implementation Method 4
dissolving the N-vinyl carboxylic acid amide monomer crystals separated in the step (A) in a mixed solvent of toluene and an aliphatic hydrocarbon having 6 to 7 carbon atoms
Implementation Method 5
subjecting precipitated N-vinyl carboxylic acid amide monomer crystals to solid-liquid separation (step (A))
Data Source
AI summary
A method for producing a highly polymerizable N-vinyl carboxylic acid amide monomer includes (A) melting a crude N-vinyl carboxylic acid amide monomer comprising 50 to 88 mass % of an N-vinyl carboxylic acid amide monomer by heating, followed by cooling for precipitation, and subjecting precipitated N-vinyl carboxylic acid amide monomer crystals to solid-liquid separation (step (A)), and (B) further dissolving the N-vinyl carboxylic acid amide monomer crystals separated in step (A) in a mixed solvent of toluene and an aliphatic hydrocarbon having 6 to 7 carbon atoms, then performing crystallization, performing solid-liquid separation, and recovering an N-vinyl carboxylic acid amide monomer purified product (step (B)), wherein a mass ratio of toluene/N-vinyl carboxylic acid amide monomer crystal in step (B) is 0.01 to 0.5, and a mass ratio of aliphatic hydrocarbon having 6 to 7 carbon atoms/N-vinyl carboxylic acid amide monomer crystal in step (B) is 0.5 to 3.0.