Polythiol Synthesis via H2S and Phosphite Catalyst
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Solution Overview
Problem
Current polythiol compositions lack increased mercaptan functionality, higher molecular weight, and reduced odor, while existing processes are cumbersome and generate waste, necessitating a more efficient method for producing polythiol compositions with improved properties.
Innovation Solution
The production of polythiol compositions involving the contact of H2S, a phosphite compound, and unsaturated compounds with specific carbon-carbon double bonds, forming polythiol molecules with sulfide groups, which enhance mercaptan functionality and molecular weight, and reduce odor, using a process with fewer steps and less waste.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional polythiol production methods are used, then the basic polythiol composition is obtained, but the mercaptan functionality is insufficient and the odor is objectionable
Solution Approach 1:
The patent changes the chemical parameters of the reaction system by using a thiol-to-double bond molar ratio greater than 1:1 (specifically 1.05:1 to 5:1), which increases mercaptan functionality. Additionally, the use of H2S gas instead of traditional sulfur sources and the specific reaction conditions (temperature, pressure, catalysts) modify the reaction parameters to produce polythiols with higher molecular weight and reduced odor, directly resolving the technical contradiction.
2Productivity
If existing polythiol production processes are used, then polythiol composition is produced, but the process is cumbersome and generates waste
Solution Approach 1:
The patent extracts and eliminates the cumbersome intermediate steps and waste-generating operations from traditional polythiol production processes. By using a direct one-pot reaction of H2S with unsaturated compounds in the presence of a phosphite compound, the method removes unnecessary purification steps, solvent removal operations, and waste treatment requirements, thereby improving productivity and reducing substance loss.
Solution Approach 2:
The reaction system is designed to be self-sufficient, where the phosphite compound acts as both a catalyst and a waste-scavenging agent. The phosphite compound captures sulfur byproducts in situ, eliminating the need for separate waste treatment steps. The process is inherently clean, requiring no additional solvents or purification operations, thus achieving self-service and reducing waste.
3Quantity of substance
If conventional mercaptanization methods are used, then unsaturated compounds are converted, but the molecular weight remains low and the process requires multiple steps
Solution Approach 1:
The patent merges multiple reaction steps into a single integrated process. The conventional multi-step process involving pre-formation of disulfides, then reaction with unsaturated compounds, is consolidated into a one-pot reaction where H2S directly reacts with unsaturated compounds in the presence of phosphite catalyst. This merging increases molecular weight through efficient polymerization while reducing process complexity to a single operation.
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 resulting polythiol compositions exhibit increased mercaptan functionality, higher average molecular weight, lower vapor pressure, and less objectionable odor, with a more streamlined and efficient production process compared to traditional methods.
Implementation Method 1
contacting H2S, a phosphite compound, and an unsaturated compound having two or three carbon-carbon double bonds; and forming the polythiol composition
Data Source
AI summary
The present invention discloses polythiol compositions containing polythiol molecules having both thiol groups and intermolecular sulfide groups. Processes for producing such polythiol compositions also are described.