Lenthionine Synthesis via Phase-Transfer Catalysis

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Solution Overview

Problem

Current methods for synthesizing 1,2,3,5,6-pentathiepane (lenthionine) face challenges such as the need for industrially difficult purification due to the generation of insoluble polysulfide compounds, which complicates industrialization and purity attainment.

Innovation Solution

A method involving the reaction of trithiocarbonate, sulfur, and methane dihalide using a phase-transfer catalyst in a multi-layer system, followed by separation of layers and termination with an acid, to produce high purity lenthionine efficiently.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If conventional synthesis methods using dimethyl disulfide or sodium sulfide are used, then lenthionine can be synthesized, but column chromatography is required for purification which is industrially disadvantageous

Engineering Contradiction:
Improvepurity of lenthionineVSAvoidindustrialization difficulty
Core Design Contradiction:
Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The invention changes the chemical parameters of the synthesis method by using trithiocarbonate instead of conventional starting materials, and by controlling the reaction conditions (aqueous-organic two-phase system, phase-transfer catalyst, specific temperature range) to achieve both high purity and industrial feasibility without requiring column chromatography

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention introduces a phase-transfer catalyst as an intermediary substance that enables the reaction to proceed efficiently in the aqueous-organic two-phase system, facilitating mass transfer between phases and allowing the reaction to achieve high purity products that can be separated by simple filtration rather than complex chromatography

Inventive Principle:
Principle #24Intermediary (Mediator)

2Ease of manufacture

If dimethyl disulfide is used as a starting material, then lenthionine synthesis is possible, but dimethyl disulfide is industrially not easy to obtain as a raw material

Engineering Contradiction:
Improveavailability of raw materialVSAvoidpurity of lenthionine
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The invention changes the starting material from dimethyl disulfide (which is industrially difficult to obtain) to trithiocarbonate (which is easily available industrially), while maintaining or improving the purity of the final product through the controlled two-phase reaction system

Inventive Principle:
Principle #35Parameter changes

3Productivity

If disulfide bond or trisulfide bond is cleaved in lenthionine, then polymerization progresses and results in insoluble polysulfide compound, but this makes purification difficult and reduces yield

Engineering Contradiction:
Improveyield of lenthionineVSAvoidpurity of lenthionine
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The invention applies preliminary anti-action by using a phase-transfer catalyst in an aqueous-organic two-phase system that prevents the cleavage of disulfide and trisulfide bonds in lenthionine during synthesis. The organic phase acts as a protective environment that prevents polymerization, thereby avoiding the formation of insoluble polysulfide compounds and ensuring both high yield and high purity without requiring extensive purification

Inventive Principle:
Principle #9Preliminary anti-action

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 method allows for the convenient production of high purity lenthionine with improved yield and reduced polysulfide generation, facilitating its use in various applications like enhancing optical material performance.

Implementation Method 1

a step of carrying out reaction of trithiocarbonate, sulfur and methane dihalide using a phase-transfer catalyst in a multi-layer system having an aqueous layer and an organic layer

Methodology Applied
Scientific EffectPhase-transfer catalysis: Surfactant

Data Source

PatentUS11919877B2Production method for 1,2,3,5,6-pentathiepane
Publication Date: 2024.03.05 MITSUBISHI GAS CHEM CO INC

AI summary

The present invention enables provision of a production method for 1,2,3,5,6-pentathiepane, the method comprising, in the following order, step A for reacting a trithiocarbonate, sulfur, and a methane dihalide together using a phase-transfer catalyst in a multilayer system having a water layer and an organic layer, step B for separating the water layer from the organic layer, and step C for stopping the reaction using an acid.