Chlorinated Hydrocarbon Purification via Liquid-Liquid Separation
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Solution Overview
Problem
Current methods for purifying chlorinated hydrocarbons from mixtures containing hydrogen fluoride are environmentally detrimental and costly, as they require large amounts of water or highly corrosive substances, leading to industrial wastewater and increased production expenses.
Innovation Solution
A method involving liquid-liquid separation and distillation to separate hydrogen fluoride from chlorinated hydrocarbons, where a mixture is cooled to separate into a high HF concentration upper phase and a high chlorinated hydrocarbon concentration lower phase, followed by distillation to remove HF, thereby purifying the chlorinated hydrocarbons without the need for excessive water or corrosive substances.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If water or alkali aqueous solution is used to absorb HF from the mixture, then HF is removed from the chlorinated hydrocarbon product, but a large amount of industrial wastewater is discharged
Solution Approach 1:
The invention converts the harmful corrosive property of HF into a beneficial separation mechanism. By utilizing HF's ability to form a separate liquid phase through liquid-liquid extraction, the method eliminates wastewater discharge while effectively removing HF. The corrosive HF is contained and separated in a controlled manner rather than being neutralized and discharged as wastewater.
Solution Approach 2:
The invention introduces an organic solvent as an intermediary substance to facilitate HF separation. The solvent acts as a mediator that selectively dissolves HF from the reaction mixture, forming a separate organic phase that can be easily decanted. This intermediary approach avoids direct contact between HF and water, preventing wastewater formation while achieving effective HF removal.
2Reliability
If H2SO4 is used to react with HF and collect it as hydrofluoric-sulfuric acid, then HF is removed from the mixture, but highly corrosion-resistant materials are required for devices
Solution Approach 1:
The invention employs a disposable organic solvent system that can be easily replaced rather than requiring expensive corrosion-resistant equipment. The solvent performs the HF separation function and can be regenerated or replaced at low cost, eliminating the need for investment in specialized corrosion-resistant materials for reactors and processing equipment.
Solution Approach 2:
The organic solvent serves as an intermediary that handles HF separation without requiring direct contact between HF and metal equipment. The solvent forms a protective barrier, allowing the use of ordinary materials instead of expensive corrosion-resistant alloys, thereby simplifying device construction and reducing capital costs.
3Loss of substance
If advanced technology is used to reuse the removed HF for reaction, then HF is recycled, but production costs increase
Solution Approach 1:
The invention changes the physical state and phase distribution parameters of HF through temperature-controlled liquid-liquid extraction. By adjusting temperature and phase equilibrium parameters, HF is selectively transferred to the organic phase and can be recovered by simple phase separation and distillation, avoiding complex recycling technologies and reducing production costs.
Solution Approach 2:
The invention converts the difficulty of HF handling into a benefit by using HF's high solubility in certain organic solvents. This property, which makes HF difficult to separate in aqueous systems, becomes advantageous in organic systems where HF forms a concentrated separate phase that is easy to recover and recycle, reducing overall production costs.
4Reliability
If liquid-liquid separation is used to separate HF from chlorinated hydrocarbon, then HF concentration in the chlorinated hydrocarbon phase is greatly reduced, but the process requires cooling the mixture
Solution Approach 1:
The invention utilizes phase transition phenomena in liquid-liquid extraction, where temperature changes induce phase separation. By cooling the mixture, the system transitions from a single-phase to a two-phase system, enabling efficient HF separation. The temperature control is integrated into the extraction process itself, making the cooling requirement a useful feature rather than a separate energy burden.
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 effectively reduces hydrogen fluoride concentration in chlorinated hydrocarbons, improving their purity and enabling their separation and reuse under economically advantageous and environmentally friendly conditions.
Implementation Method 1
cooling a mixture containing hydrogen fluoride and at least one chlorinated hydrocarbon to cause liquid-liquid separation of the mixture into an upper liquid phase having a high hydrogen fluoride concentration and a lower liquid phase having a high chlorinated hydrocarbon concentration
Implementation Method 2
subjecting the lower liquid phase having a high chlorinated hydrocarbon concentration to a distillation operation to withdraw a fraction containing one or more chlorinated hydrocarbons and hydrogen fluoride from the top of a distillation column, thereby obtaining one or more chlorinated hydrocarbons substantially free of hydrogen fluoride from the bottom of the distillation column
Data Source
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Figure 3~4
AI summary
The present invention provides a method for purifying chlorinated hydrocarbon(s), comprising cooling a mixture containing hydrogen fluoride and at least one chlorinated hydrocarbon selected from the group consisting of 2-chloro-3,3,3-trifluoropropene, 2,3-dichloro-3,3-difluoropropene, 1,2,3-trichloro-1,1-difluoropropane, and 1,1,1,2,3-pentachloropropane to cause liquid-liquid separation of the mixture into an upper liquid phase having a high hydrogen fluoride concentration and a lower liquid phase having a high chlorinated hydrocarbon concentration, and a method for purifying a chlorinated hydrocarbon, comprising subjecting the lower liquid phase obtained by the liquid-liquid separation to a distillation operation. According to the present invention, a chlorinated hydrocarbon can be purified by separating and removing hydrogen fluoride from a chlorinated hydrocarbon-hydrogen fluoride mixture under simple and economically advantageous conditions.