Polythiol Synthesis via Controlled 2-Mercaptoethanol Water Content
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Solution Overview
Problem
Conventional methods for producing polythiol compounds face challenges in achieving high yield and reducing coloration, particularly due to moisture content in 2-mercaptoethanol used as a starting material.
Innovation Solution
A method involving the reaction of 2-mercaptoethanol with epihalohydrin, followed by reaction with an alkali metal compound, thiourea, and subsequent hydrolysis steps, is employed to produce polythiol compounds with reduced coloration and improved yield, utilizing 2-mercaptoethanol with a water content of 3000 ppm or less to minimize hydrolysis and enhance productivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional methods are used to produce polythiol compounds, then production can proceed with readily available materials, but yield constant is insufficient and coloration increases
Solution Approach 1:
The patent applies parameter changes by strictly controlling the water content of 2-mercaptoethanol to 3000 ppm or less, which is a specific parameter change in the starting material. This parameter control prevents hydrolysis of the thiol group and subsequent polymerization, thereby improving both yield constant and reducing coloration of the polythiol compound.
Solution Approach 2:
The patent implements preliminary anti-action by taking measures before the harmful effects occur. Specifically, the water content of 2-mercaptoethanol is controlled to 3000 ppm or less before the reaction begins, preventing hydrolysis and polymerization that would otherwise occur during the reaction process, thus improving yield and reducing coloration.
2Ease of manufacture
If 2-mercaptoethanol with higher water content is used, then ease of manufacture is improved, but hydrolysis occurs leading to reduced yield and increased coloration
Solution Approach 1:
The patent applies parameter changes by setting a specific water content threshold (3000 ppm or less) for 2-mercaptoethanol. This parameter specification balances ease of manufacture with manufacturing precision, ensuring high yield constant while maintaining practical manufacturability through a clearly defined material specification.
3Device complexity
If water content in 2-mercaptoethanol is not controlled, then process simplicity is maintained, but hydrolysis of thiol group occurs causing polymerization and reduced product quality
Solution Approach 1:
The patent implements preliminary anti-action by controlling the water content of 2-mercaptoethanol to 3000 ppm or less before the reaction begins. This preliminary measure prevents hydrolysis of the thiol group and subsequent polymerization, thereby maintaining product purity and compositional stability without requiring complex process controls during the reaction.
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 approach results in polythiol compounds with significantly reduced coloration and improved yield constants, suitable for use in synthesizing resins with desirable physical properties such as high refractive index and heat resistance.
Implementation Method 1
step 1 of reacting 2-mercaptoethanol having a water content of 3000 ppm or less on a mass basis, with epihalohydrin to obtain a halide represented by formula (1)
Implementation Method 2
step 2 of reacting the halide represented by formula (1) with an alkali metal compound selected from the group consisting of an alkali metal sulfide and an alkali metal hydroxide to obtain a polyol compound
Implementation Method 3
step 3 of reacting the polyol compound with thiourea in the presence of an acid to obtain an isothiuronium salt
Implementation Method 4
step 4 of hydrolyzing the isothiuronium salt in the presence of a base to obtain a polythiol salt
Implementation Method 5
step 5 of converting the polythiol salt into a polythiol by an acid to obtain at least one polythiol compound selected from the group consisting of a polythiol compound represented by formula (4), a polythiol compound represented by formula (5), a polythiol compound represented by formula (6), and a polythiol compound represented by formula (7)
Data Source
AI summary
Provided is a method for producing a polythiol compound, the method including: step 1 of reacting 2-mercaptoethanol having a water content of 3000 ppm or less on a mass basis, with epihalohydrin to obtain a halide represented by the formula (1), wherein X represents a halogen atom; step 2 of reacting the halide represented by the formula (1) with an alkali metal compound selected from the group consisting of an alkali metal sulfide and an alkali metal hydroxide to obtain a polyol compound selected from the group consisting of a polyol compound represented by the formula (2) and a polyol compound represented by the formula (3); step 3 of reacting the polyol compound with thiourea in the presence of an acid to obtain an isothiuronium salt; step 4 of hydrolyzing the isothiuronium salt in the presence of a base to obtain a polythiol salt; and step 5 of converting the polythiol salt into a polythiol by an acid to obtain at least one polythiol compound selected from the group consisting of a polythiol compound represented by the formula (4), a polythiol compound represented by the formula (5), a polythiol compound represented by the formula (6), and a polythiol compound represented by the formula (7).