Chlorohydrin Production via Water Removal and Catalyst Separation
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Solution Overview
Problem
Current methods for preparing chlorohydrins from polyhydroxy aliphatic hydrocarbons, such as glycerol, face challenges including decreased reaction rate and selectivity due to water by-products, leading to increased reaction time and costs, especially when using propylene, which has unstable supply and generates significant waste.
Innovation Solution
A method involving a series of reaction steps including a first reaction step, water removal, and a second reaction step, with the use of a catalyst and chlorination agent, followed by contacting the chlorohydrins composition with an alkaline agent to remove the catalyst as an alkali metal salt, optimizing conditions for temperature, pressure, and catalyst selection to enhance selectivity and efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If polyhydroxy aliphatic hydrocarbon is reacted with a chlorination agent in the presence of a catalyst to prepare chlorohydrins, then manufacturing cost decreases and environmental friendliness improves, but water is generated as a by-product which inhibits the chlorination reaction, causing reaction rate to decrease and reaction time to increase
Solution Approach 1:
The patent extracts water, the harmful by-product, from the reaction system by introducing a water-soluble catalyst that allows water to be separated from the organic phase. This separation removes the inhibiting effect of water on the chlorination reaction, maintaining high reaction rates while still using the environmentally friendly polyhydroxy aliphatic hydrocarbon route.
Solution Approach 2:
The patent introduces a water-soluble catalyst as an intermediary substance that facilitates the separation of water from the reaction mixture. This catalyst acts as a mediator between the aqueous by-product and the organic reaction system, enabling efficient water removal while maintaining catalytic activity for the chlorination reaction.
2Ease of manufacture
If polyhydroxy aliphatic hydrocarbon is reacted with a chlorination agent in the presence of a catalyst to prepare chlorohydrins, then manufacturing cost decreases and environmental friendliness improves, but selectivity of chlorohydrins decreases due to water inhibition
Solution Approach 1:
The patent extracts water from the reaction system using a water-soluble catalyst, preventing water from interfering with the selectivity of the chlorination reaction. By removing water, the reaction maintains high selectivity for the desired chlorohydrin products while still benefiting from the low-cost, environmentally friendly polyhydroxy aliphatic hydrocarbon feedstock.
3Reliability
If the propylene method is used to prepare chlorohydrins, then established industrial process is available, but unstable supply of propylene due to price increase and generation of great quantities of waste water and waste matter occurs
Solution Approach 1:
The patent converts the harmful waste water by-product into a separable phase by using a water-soluble catalyst. The water, instead of being mixed with organic waste requiring complex treatment, forms a separate aqueous phase that can be easily removed. This transforms the waste problem into a simple separation task, significantly reducing waste treatment requirements.
4Ease of manufacture
If excess industrial water is used in the propylene chlorohydrin method, then chlorohydrins can be prepared, but great quantities of waste water are generated
Solution Approach 1:
The patent extracts and separates water from the reaction mixture using a water-soluble catalyst, preventing the accumulation of large amounts of waste water. By continuously removing water during the reaction, the process maintains feasibility without requiring excess water, thereby eliminating the source of the waste water problem inherent in conventional methods.
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 improves the selectivity and efficiency of chlorohydrins production, reducing waste and initial investment costs by using glycerol as a cheap raw material and minimizing water usage, while effectively converting glycerol into valuable chlorohydrins like epichlorohydrin.
Implementation Method 1
reacting polyhydroxy aliphatic hydrocarbon with a chlorination agent in the presence of a catalyst
Implementation Method 2
contacting the chlorohydrins composition with an alkaline agent, and removing the catalyst included in the chlorohydrins composition in the form of an alkali metal salt
Data Source
Figure 1
AI summary
Disclosed are a method for preparing chlorohydrins composition and a method for preparing epichlorohydrin using chlorohydrins prepared thereby. The disclosed method for preparing chlorohydrins composition reacts polyhydroxy aliphatic hydrocarbon with a chlorination agent in the presence of a catalyst, comprises at least one combination of a series of unit operations including a first reaction step, a water removal step, and a second reaction step in the respective order, and additionally comprises a step for reacting the chlorohydrins composition derived from a plurality of reaction mixtures discharged from the plurality of reaction steps with an alkaline chemical, and removing the catalyst included in the chlorohydrins composition in the form of an alkali metal salt. The disclosed method for preparing epichlorohydrin includes a step for contacting the chlorohydrins composition, which was prepared using the method for preparing chlorohydrins composition, with an alkaline chemical.