Mono Vinyl Thioether Synthesis via Low Pressure Acetylene Addition
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Solution Overview
Problem
Existing methods for synthesizing vinyl compounds with a thioether group and a free hydroxy group result in mixtures of various vinyl compounds, making them unsuitable for specific technical applications, and there is a need for an efficient process to produce pure compounds with high yield and selectivity.
Innovation Solution
A process involving the reaction of acetylene with a thiol-hydroxy compound at pressures below 2 bars in the presence of an alkali salt catalyst, preferably prepared from a metal hydroxide, at elevated temperatures, to produce mono vinyl thioethers with high selectivity and low divinyl by-product formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the reaction is performed at high pressure (20 bars) according to the Reppe process, then the reaction proceeds efficiently, but a mixture of various vinyl compounds is obtained including thiol vinyl ether, hydroxy vinyl thioether and divinyl compounds
Solution Approach 1:
The patent changes the pressure parameter from conventional high pressure (20 bars) to low pressure (below 2 bars), and modifies the catalyst system by using alkali metal salts (NaOH, KOH, CsOH) instead of conventional bases. This parameter change selectively suppresses the formation of unwanted by-products while maintaining reasonable reaction efficiency, achieving high product purity with minimal separation work required.
2Productivity
If conventional bases are used as catalysts in the Reppe process, then the reaction can proceed, but the selectivity towards the desired mono vinyl thioether is poor
Solution Approach 1:
The patent changes the catalyst type from conventional organic bases to inorganic alkali metal salts (NaOH, KOH, CsOH) with specific attention to their solubility and strength characteristics. This catalyst parameter change provides superior selectivity for forming the desired mono vinyl thioether while maintaining acceptable reaction rates, effectively resolving the selectivity issue.
3Productivity
If the reaction is performed to obtain high yield of vinyl compounds, then production efficiency increases, but the mixture contains high amounts of divinyl by-products that are difficult to separate
Solution Approach 1:
The patent changes the reaction conditions by operating at low pressure (below 2 bars) and using alkali metal salt catalysts, which fundamentally alters the reaction pathway to suppress divinyl by-product formation. This results in high yield of the desired mono vinyl thioether with minimal separation work required, as the by-products are formed in trace amounts rather than requiring complex separation processes.
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 process achieves high yields of pure mono vinyl thioethers with minimal divinyl by-products, ensuring high selectivity and ease of separation, suitable for technical applications such as polymerization processes.
Implementation Method 1
The reaction is preferably performed in presence of a catalyst. The catalyst is preferably an alkali salt of the thiol-hydroxy compound.
Implementation Method 2
reacting the metal hydroxide with the thiol-hydroxy compound at elevated temperatures, for example at 50 to 150° C.
Data Source
AI summary
A process to produce a mono vinyl thioether by reacting acetylene with a compound comprising one thiol group and one hydroxy group, hereinafter referred to as thiol-hydroxy compound, wherein the reaction is performed at a pressure below 2 bars.