Electrochemical 1,4-Halogenation of Conjugated 1,3-Dienes
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional halogenation methods for conjugated 1,3-diene compounds result in low selectivity and safety hazards due to the use of elemental chlorine or bromine, leading to the production of undesirable side products and environmental concerns with organic halogen sources like HCH and HBCD.
Innovation Solution
A process involving the electrolysis of a liquid reaction mixture containing a 1,3-diene compound, a halogen source (chlorine or bromine), a solvent, and a conducting salt in an undivided electrolysis cell to achieve selective 1,4-chlorination or 1,4-bromination, utilizing organic halogen sources and electricity as a safe oxidizing agent.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If elemental chlorine or bromine is used for halogenation of conjugated 1,3-diene compounds, then the halogenation reaction can proceed, but the selectivity is low and side reactions occur
Solution Approach 1:
The patent introduces an intermediary substance (a compound with a double bond capable of forming a cyclic intermediate) that mediates between the halogen source and the 1,3-diene compound. This intermediary forms a cyclic intermediate structure that directs the halogenation to occur selectively at the 1,4-position, preventing random side reactions and improving manufacturing precision.
2Productivity
If elemental chlorine or bromine is used for halogenation, then the reaction can proceed, but safety hazards and corrosion issues arise
Solution Approach 1:
The patent replaces toxic and corrosive elemental halogens with safer, more stable organic halogen sources (such as alkyl halides or halogenated hydrocarbons). These alternative sources are less hazardous, easier to handle, and can be disposed of or degraded more safely, eliminating the safety hazards associated with elemental chlorine and bromine while maintaining reaction functionality.
3Ease of manufacture
If organic halogen sources like HCH or HBCD are used, then halogenation can occur, but environmental degradation problems arise
Solution Approach 1:
The patent changes the chemical parameters of the halogen source by using specifically designed organic halogen compounds that can be readily degraded. These compounds are selected or modified to have structural features that enable fast environmental breakdown (e.g., through hydrolysis or microbial degradation), transforming them from persistent pollutants into environmentally benign substances that complete their function and disappear quickly from the environment.
4Manufacturing precision
If conventional halogenation methods are used, then 1,4-dichloro- or 1,4-dibromo-2-monoenes can be produced, but yields and selectivities are insufficient
Solution Approach 1:
The patent segments the halogenation process into distinct steps: first, the formation of a cyclic intermediate structure through reaction of the intermediary with the halogen source; second, the ring-opening and rearrangement to form the final 1,4-halogenated product. This segmentation allows each step to be optimized independently, improving both the selectivity (by controlling the cyclic intermediate formation) and the yield (by optimizing the ring-opening step).
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 achieves high selectivity and yield in producing 1,4-dichloro- or 1,4-dibromo-2-monoenes while avoiding reagent waste and safety hazards, using organic halogen sources and electricity as a cost-effective oxidizing agent.
Implementation Method 1
the electrolysis of a liquid reaction mixture containing a 1,3-diene compound, at least one halogen source containing chlorine or bromine, at least one solvent and at least one conducting salt in an undivided electrolysis cell
Data Source
AI summary
The present invention relates to a process for the 1,4-chlorination or 1,4-bromination of conjugated 1,3-diene compounds. Process comprising the electrolysis of a liquid reaction mixture containing a 1,3-diene compound, at least one halogen source containing chlorine or bromine, at least one solvent and at least one conducting salt in an undivided electrolysis cell.