Polythiol Synthesis via Phosphite Catalysis for Low Odor Adhesives
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Solution Overview
Problem
Current processes for producing polythiol compositions often result in products with offensive odors, limiting their use in certain applications, and there is a need for efficient methods to form polythiol compositions with specific sulfur-containing compounds for adhesive and curing agent applications.
Innovation Solution
A process involving the contact of a hydrocarbon compound with at least two olefinic double bonds, hydrogen sulfide (H2S), and a phosphite compound, with controlled molar ratios and conditions, to form polythiol compositions that include sulfur-containing compounds such as trimercaptocyclododecane and dimercaptocyclododecene, reducing odor and improving application suitability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If conventional processes are used to produce polythiol compositions, then polythiol compositions can be formed, but the products have offensive odors that limit their use in certain applications
Solution Approach 1:
The patent changes the chemical parameters of the reaction process by using specific molar ratios of H2S to olefinic double bonds (10:1 to 500:1) and employing phosphite compounds as catalysts. These parameter changes produce polythiol compositions with reduced offensive odors while maintaining the desired sulfur-containing compound content, thereby resolving the contradiction between odor reduction and application suitability.
2Quantity of substance
If the molar ratio of H2S to olefinic double bond is increased to improve sulfur content, then more sulfur-containing compounds are formed, but the odor may increase
Solution Approach 1:
The patent introduces phosphite compounds as intermediary catalysts in the reaction between H2S and olefinic hydrocarbons. These intermediaries facilitate the formation of sulfur-containing compounds at controlled rates, allowing high sulfur content to be achieved without proportionally increasing offensive odors, thus resolving the contradiction between quantity of sulfur and odor levels.
3Reliability
If specific sulfur-containing compounds are targeted for adhesive applications, then performance is improved, but the process complexity increases
Solution Approach 1:
The patent applies local quality by selecting specific phosphite compounds and controlling reaction conditions to favor the formation of particular sulfur-containing compounds (such as cyclic disulfides and polysulfides) that are optimal for adhesive applications. This targeted approach improves adhesive performance while managing process complexity through focused chemical selectivity rather than complex multi-step 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
The process effectively produces polythiol compositions with reduced odor and specific sulfur content, making them suitable for use as curing agents in adhesives and other applications, with improved performance and lower objectionable smell.
Implementation Method 1
contacting a) a hydrocarbon compound having at least two olefinic double bonds; b) H2S; and c) a phosphite compound; and forming the polythiol composition
Data Source
AI summary
The present invention discloses processes for forming polythiol compositions from olefinic hydrocarbons such as cyclooctadiene, cyclododecatriene, and trivinylcyclohexane. The polythiol compositions produced from these processes, including the sulfur-containing compounds of these compositions, also are described.