3-Chloro-2-Vinylphenol Synthesis Using Deep Eutectic Solvents
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Solution Overview
Problem
Current methods for synthesizing 3-chloro-2-vinylphenol face challenges such as the use of reproduction-toxic solvents, high energy requirements, low yields, and the need for purification due to acidic conditions, making them unsuitable for industrial applications.
Innovation Solution
A process involving the reaction of 1,5,5-trichloro-6-vinyl-7-oxabicyclo[4.1.0]heptane with a base and a dipolar aprotic additive, preferably N,N-dimethylacetamide, in the presence of a solvent like n-butyl acetate, at controlled temperatures to achieve high yields and purity of 3-chloro-2-vinylphenol.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If N,N-dimethylformamide (DMF) is used as solvent for the elimination reaction, then the reaction can proceed, but the solvent is reproduction-toxic and difficult to separate from product and aqueous wastes
Solution Approach 1:
The patent changes the solvent parameter from DMF to a eutectic mixture of choline chloride and water (deep eutectic solvent). This parameter change eliminates the toxicity and separation difficulties associated with DMF while maintaining the reaction's feasibility. The new solvent system allows for easier separation and is environmentally friendly.
Solution Approach 2:
The patent employs a water-based deep eutectic solvent system that can be easily disposed of or recycled without environmental harm. The choline chloride-water mixture is non-toxic and can be separated from the organic product through simple extraction, eliminating the need for expensive purification steps required with DMF.
2Productivity
If the reaction is carried out at 153° C. to eliminate hydrogen chloride, then the elimination reaction proceeds, but the energy consumption is high and hydrogen chloride contributes to solvent decomposition
Solution Approach 1:
The patent introduces a base (such as potassium carbonate, sodium hydroxide, or triethylamine) as an intermediary substance that facilitates the elimination of hydrogen chloride at lower temperatures. The base acts as a catalyst and hydrogen chloride acceptor, enabling the reaction to proceed at 80-120° C. instead of 153° C., thereby reducing energy consumption and preventing solvent decomposition.
3Use of energy by moving object
If the reaction temperature is reduced to save energy, then energy consumption decreases, but the reaction selectivity and product stability deteriorate under acidic conditions
Solution Approach 1:
The base intermediary not only enables lower temperature operation but also maintains reaction selectivity by neutralizing acidic conditions. The base prevents unwanted side reactions and product decomposition that would occur under acidic conditions, even at reduced temperatures. This dual function allows the patent to achieve both energy savings and high selectivity.
4Ease of manufacture
If inorganic catalysts such as calcium oxide or barium chloride are used for elimination, then the elimination reaction can occur, but the reaction requires temperatures of 300-500° C. which is energy-intensive
Solution Approach 1:
The patent changes the catalyst type from inorganic catalysts (calcium oxide, barium chloride) requiring 300-500° C. to organic bases (potassium carbonate, sodium hydroxide, triethylamine) that enable the reaction at 80-120° C. This parameter change in catalyst chemistry dramatically reduces the temperature requirement and energy consumption while maintaining reaction feasibility.
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 overcomes previous disadvantages by achieving high yields and purity of 3-chloro-2-vinylphenol, allowing for direct further reactions without prior purification and reducing environmental and economic concerns.
Implementation Method 1
1,5,5-Trichloro-6-vinyl-7-oxabicyclo[4.1.0]heptane is refluxed in N,N-dimethylformamide (DMF), forming 3-chloro-2-vinylphenol by elimination of two equivalents of hydrogen chloride
Implementation Method 2
A process involving the reaction of 1,5,5-trichloro-6-vinyl-7-oxabicyclo[4.1.0]heptane with a base and a dipolar aprotic additive, preferably N,N-dimethylacetamide
Data Source
AI summary
The present invention describes a novel process for preparing 3-chloro-2-vinylphenol which, owing to the chemoselectivity achieved, also allows direct conversion into (3-chloro-2-vinylphenyl)methane-sulphonate.