Epichlorohydroxy Process Using Two-Phase Hydrodynamics
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Solution Overview
Problem
The existing processes for manufacturing 1,2-epoxy-3-chloropropane (epichlorohydrin) using allyl chloride and hydrogen peroxide are complex and costly due to the need for large quantities of methanol as a solvent, which complicates solvent separation and recycling, and the use of mechanically stirred reactors, leading to high operational costs and mechanical constraints.
Innovation Solution
A process involving a solid catalyst in a two-liquid phase reaction medium with controlled hydrodynamic conditions, including a total liquid linear velocity of 0.01-1 m/s and pressure drop of ≤25 kPa/m, allowing for easy catalyst separation and regeneration, reduced solvent usage, and the use of fixed or fluid-bed reactors, thereby simplifying the process and reducing costs without compromising reaction rate or selectivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If large quantities of methanol are used as solvent to ensure good catalyst activity and selectivity, then the epoxidation reaction efficiency is improved, but the process complexity and cost increase due to solvent separation and recycling requirements
Solution Approach 1:
The invention changes the physical state parameter of the reaction system from homogeneous (single liquid phase) to heterogeneous (two liquid phases), allowing the catalyst to be in a separate phase from the bulk reaction mixture. This phase separation enables easy catalyst recovery without complex solvent recycling systems, while maintaining high catalyst activity through optimal dispersion in the aqueous phase.
Solution Approach 2:
The invention extracts the catalyst from the organic solvent phase and places it in the aqueous phase, separating the catalytic function from the organic solvent environment. This allows the use of minimal or no organic solvent while maintaining catalyst activity, thereby eliminating the need for complex solvent separation and recycling infrastructure.
2Productivity
If mechanically stirred reactors are used to ensure good mixing and reaction control, then the reaction efficiency is improved, but the operational cost and mechanical constraints on catalyst and reactor parts increase
Solution Approach 1:
The invention replaces the mechanical stirring system with a hydrodynamic mixing approach. The two-liquid-phase system naturally creates circulation and mixing through density differences and flow patterns, eliminating the need for mechanical stirrers. This substitution removes mechanical constraints on catalyst particles and reactor components while maintaining efficient mass transfer and reaction control.
Solution Approach 2:
The reaction system utilizes the inherent properties of the two-liquid-phase mixture to achieve self-mixing and self-circulation. The density difference between phases and the flow dynamics create automatic mixing without external mechanical intervention, reducing operational complexity and mechanical wear on reactor components.
3Productivity
If powder catalyst is used to ensure high surface area and activity, then the catalytic performance is improved, but the catalyst separation and reactor complexity increase due to the need for slurry reactors
Solution Approach 1:
The invention segments the reaction system into two distinct liquid phases, with the catalyst-containing aqueous phase separated from the organic phase. This segmentation allows the use of fine powder catalyst in the aqueous phase while enabling easy separation through phase decantation, avoiding the need for complex filtration or centrifugation systems required for slurry reactors.
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 approach significantly reduces the complexity and cost of the process, enhances epichlorohydrin purity, minimizes byproduct contamination, and allows for continuous operation with minimal impact on reaction rate and selectivity, achieving high epichlorohydrin productivity with reduced solvent recycling and reactor complexity.
Implementation Method 1
reaction between allyl chloride and hydrogen peroxide in the presence of a solid catalyst
Implementation Method 2
total liquid linear velocity higher than or equal to 0.01 m/s and lower than or equal to 1 m/s
Implementation Method 3
pressure drop across the reaction zone is lower than or equal to 25 kPa/m
Data Source
AI summary
Process for the manufacture of 1,2-epoxy-3-chloropropane by reaction between allyl chloride and hydrogen peroxide in the presence of a solid catalyst and in the possible presence of at least one solvent in an epoxidation medium comprising at least two liquid phases under the conditions of reaction, comprising feeding continuously a reaction zone comprising the catalyst with at least allyl chloride, hydrogen peroxide and possibly at least one solvent at a total liquid linear velocity higher than or equal to 0.01 m/s and lower than or equal to 1 m/s, wherein the pressure drop across the reaction zone is lower than or equal to 25 kPa/m.