Thiourea-Substituted Chitosan for Optical Isomer Resolution
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Solution Overview
Problem
Existing separating agents for optical isomers, such as those using chitosan compounds with hydroxyl groups substituted with carbamate and urea groups, lack investigation into alternative substituents for improved optical resolution ability.
Innovation Solution
A chitosan compound where the amino group at the 2-position is substituted with a thiourea group, combined with a carrier, enhances the optical resolution ability for specific racemates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional chitosan compounds with carbamate and urea groups are used, then the separating agent has basic optical resolution ability, but the optical resolution ability is insufficient for specific racemates
Solution Approach 1:
The patent changes the chemical parameter of the substituent group at the 2-position of chitosan from traditional urea or carbamate groups to thiourea groups. This parameter change fundamentally alters the chemical properties of the separating agent, enabling it to achieve excellent optical resolution ability for specific racemates that traditional compounds cannot resolve effectively
Solution Approach 2:
The patent creates a composite chitosan compound by combining thiourea groups at the 2-position with carbamate groups at the 3- and 6-positions. This composite structure integrates the advantages of different functional groups, resulting in a separating agent with enhanced and specialized optical resolution ability for specific racemates
2Ease of manufacture
If chitosan compounds with substituted hydroxyl groups are used, then the separating agent can be constituted with carrier and macromolecule, but the separation ability for specific racemates remains uninvestigated and insufficient
Solution Approach 1:
The patent applies local quality by specifically substituting the amino group at the 2-position with thiourea groups while maintaining carbamate groups at the 3- and 6-positions. This localized substitution at specific positions of the chitosan structure creates distinct functional regions that provide excellent separation ability for specific racemates while maintaining the overall separable structure
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 novel chitosan compound with thiourea substitution demonstrates excellent separation ability for optical isomers, outperforming traditional chitosan compounds in resolving racemates.
Implementation Method 1
Methods of manufacturing an optical isomer requiring such high optical purity known in the art include a method involving separating one of the optical isomers from a mixture of optical isomers, such as a racemate, by using a column packed with a separating agent for optical isomers, the separating agent having optical resolution ability, in chromatography
Data Source
AI summary
Provided are a novel chitosan compound represented by Formula (I) and a separating agent for optical isomers. In Formula (I), each R is independently a group represented by Formula (II) or a group represented by Formula (III); Ra is an alkyl group having from 1 to 5 carbons or an alkyl group having from 3 to 5 carbons and having a branched chain; and n is an integer of 5 or greater; and in Formulas (II) and (III), each Rb is independently an unsubstituted phenyl group, a phenyl group having a substituent, an unsubstituted cyclohexyl group, or a cyclohexyl group having a substituent, and each of the substituent is independently an alkyl group having from 1 to 5 carbons, or a halogen.