Cyclic Monothiocarbonate Synthesis Without Phosgene
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Solution Overview
Problem
Existing methods for synthesizing compounds with cyclic monothiocarbonate groups are complex and often involve the use of harmful materials like phosgene, resulting in low yields and the formation of by-products.
Innovation Solution
A process involving the reaction of a salt of an acidic compound with hydrogen sulfide or an organic compound containing hydroxy, thiol, imide, or carboxylic groups with a compound having an alkylene group and a halide, specifically using 5-(chloromethyl)-1,3-oxathiolane-2-one, to introduce cyclic monothiocarbonate functionality without ring opening reactions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If existing methods are used to synthesize compounds with cyclic monothiocarbonate groups, then the synthesis can be achieved, but the process is complex and involves harmful materials like phosgene resulting in low yields and formation of by-products
Solution Approach 1:
The patent extracts and eliminates the harmful phosgene step from the synthesis pathway. Instead of using phosgene to form the monothiocarbonate group, the invention uses a two-step alternative: first forming a cyclic carbonate intermediate, then introducing the sulfur atom through reaction with a sulfur source, thereby removing the harmful substance while achieving the same functional group
Solution Approach 2:
The patent converts the previously harmful phosgene reaction into a beneficial two-step process where the first step creates a stable cyclic carbonate intermediate that can be isolated and purified, and the second step introduces sulfur under milder conditions, transforming a harmful one-step reaction into a beneficial sequential process that eliminates harmful by-products
2Productivity
If existing synthesis methods are used, then monothiocarbonate groups can be formed, but yields are low and by-products from polymerization are observed
Solution Approach 1:
The patent segments the synthesis into two distinct steps: Step 1 forms the cyclic carbonate intermediate with high selectivity, and Step 2 introduces the sulfur atom to form the final monothiocarbonate product. This segmentation prevents polymerization by-products that occur in one-step methods, as each step can be optimized independently and the intermediate can be isolated if needed
Solution Approach 2:
The cyclic carbonate intermediate serves as a stable intermediary that mediates between the starting materials and the final monothiocarbonate product. This intermediary can be isolated, purified, and characterized, ensuring high yield and preventing polymerization that would occur if all reagents were present simultaneously
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 is economically viable, selective, and does not use harmful materials, effectively introducing monothiocarbonate groups into chemical compounds, including polymers, with high efficiency and purity.
Implementation Method 1
the salt of an acidic compound with at least one acidic hydrogen atom is reacted with a compound of formula (I)
Data Source
AI summary
Provided is a process for the preparation of a compound comprising at least one cyclic monothiocarbonate group wherein a salt of an acidic compound with at least one acidic hydrogen atom is reacted with a compound of formula (I), wherein one of the groups R1 to R4 is a group of formula -A-X (II) with A representing an organic group with at least one carbon atom and X representing a halide, and the remaining groups R1 to R4 independently from each other represent hydrogen or an organic group with 1 to 50 carbon atoms.