Amide Vinylation Residence Time Control
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Solution Overview
Problem
Existing processes for preparing N-vinyl compounds like N-vinylpyrrolidone through vinylation of pyrrolidone with acetylene in the presence of alkali metal hydroxide result in significant formation of by-products, such as aminobutyric acid, reducing yield and catalyst activity.
Innovation Solution
Reacting the compound with alkali metal hydroxide for a short average residence time of less than 6 minutes in a column, forming an alkali metal salt that catalyzes subsequent vinylation with acetylene, while maintaining high catalyst activity and minimizing by-product formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the compound is reacted with alkali metal hydroxide for a long time to ensure complete reaction, then the conversion of compound to alkali metal salt is improved, but the formation of by-products such as aminobutyric acid increases significantly
Solution Approach 1:
The patent applies the principle of rushing through the reaction by reducing the residence time of the compound with alkali metal hydroxide to less than 6 minutes. This rapid passage through the reaction zone allows sufficient conversion to form the alkali metal salt catalyst while minimizing the time available for side reactions that produce harmful by-products like aminobutyric acid, thus resolving the contradiction between conversion efficiency and by-product formation
2Object-generated harmful factors
If the residence time is reduced to minimize by-products, then by-product formation is reduced, but the catalyst activity may be adversely affected
Solution Approach 1:
The patent optimizes the residence time parameter to a specific range (less than 6 minutes, preferably 1-5 minutes) to achieve the desired balance. By precisely controlling this temporal parameter, the process ensures sufficient catalyst formation while preventing excessive by-product formation, thus maintaining both high catalyst activity and low by-product levels simultaneously
3Quantity of substance
If the reaction is carried out with traditional residence times, then complete reaction is achieved, but the space-time yield decreases due to by-product formation
Solution Approach 1:
By rushing through the reaction zone with a residence time of less than 6 minutes, the process achieves high conversion to the desired alkali metal salt catalyst without allowing significant by-product formation. This increases the proportion of useful product and improves the space-time yield, as more of the reacted material contributes to the desired outcome rather than waste products
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 process achieves high yield and purity of N-vinylamides like N-vinylpyrrolidone with reduced by-products, maintaining good space-time yield and catalyst activity, with N-vinylpyrrolidone obtainable in over 99% purity.
Implementation Method 1
When pyrrolidone reacts with an alkali metal hydroxide, a pyrrolidate is formed, which catalyzes the subsequent vinylation with acetylene
Data Source
AI summary
Process for the production of N-vinyl compound, comprises vinylation of a compound having at least one nitrogen with acetylene, where: the compound is reacted with an alkali hydroxide in a reaction zone before the vinylation; and an average dwell time of the alkali hydroxide and compound in the reaction zone is less than 6 minutes.