Ethylene Dichloride Production via Phase Separation From Monoethylene Glycol
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Solution Overview
Problem
Existing processes for producing ethylene dichloride from sustainable resources face challenges in achieving high selectivity and energy efficiency, limiting their commercial viability.
Innovation Solution
A process involving the reaction of monoethylene glycol with hydrogen chloride in the presence of water, followed by phase separation to recover ethylene dichloride, utilizing azeotropic conditions to enhance separation efficiency and recycle reactants, thereby achieving high conversion rates and purity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional catalyzed reaction of ethylene with chlorine or oxychlorination is used, then ethylene dichloride is produced, but the process cannot utilize sustainable resources and has limited commercial viability
Solution Approach 1:
The invention changes the chemical parameters of the reaction system by using monoethylene glycol and hydrogen chloride instead of traditional ethylene and chlorine feedstocks. This parameter change enables the use of sustainable resources (bio-based monoethylene glycol) while maintaining commercial viability through the specific reaction conditions and catalyst system employed.
Solution Approach 2:
The invention introduces an intermediary conversion step where monoethylene glycol is first converted to chloroethanol, which then reacts further to form ethylene dichloride. This intermediary pathway enables the use of sustainable feedstocks while achieving the desired product, bridging the gap between green chemistry and commercial viability.
2Adaptability or versatility
If alternative processes using renewable resources are used, then sustainable ethylene dichloride production is enabled, but high selectivity and energy efficiency are not achieved
Solution Approach 1:
The invention employs a feedback mechanism through the phase separation step where unreacted monoethylene glycol and byproducts are separated and can be recycled back to the reactor. This feedback loop improves overall selectivity and energy efficiency by minimizing waste and maximizing conversion of the renewable feedstock to the desired product.
Solution Approach 2:
The invention utilizes phase transitions in the separation process, where the reaction mixture is separated into organic and aqueous phases. This phase separation enables efficient recovery of ethylene dichloride while allowing recycling of unreacted renewable feedstock, thereby improving both selectivity and energy efficiency of the overall process.
3Manufacturing precision
If phase separation is used to recover ethylene dichloride, then high purity product is achieved, but the process complexity increases
Solution Approach 1:
The invention applies extraction through phase separation to isolate ethylene dichloride from the reaction mixture. By separating the organic phase containing ethylene dichloride from the aqueous phase containing unreacted monoethylene glycol and byproducts, high product purity is achieved. The simplicity of this extraction approach balances the added process step with the benefit of high purity product recovery.
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
The process achieves high selectivity and energy efficiency in producing ethylene dichloride, allowing for nearly complete conversion of monoethylene glycol to ethylene dichloride with high purity, suitable for commercial applications.
Implementation Method 1
The recovery is under conditions where two liquid phases are formed, an ethylene dichloride-rich liquid phase and an aqueous phase, and an ethylene dichloride product is recovered by phase separation
Implementation Method 2
utilizing azeotropic conditions to enhance separation efficiency
Data Source
AI summary
A process is disclosed for producing ethylene dichloride from monoethylene glycol and hydrogen chloride in the presence of water, thereby forming an ethylene dichloride-rich liquid phase that can be readily separated from a coexisting aqueous phase. The reaction is carried out under conditions that limit both 2-chloroethanol and ethylene dichloride in the vapor phase, facilitating high conversion efficiencies and minimizing ethylene dichloride losses. The process includes a reaction step in which monoethylene glycol is converted to 2-chloroethanol and subsequently to ethylene dichloride, generating water that aids in separating by-products from the ethylene dichloride-rich phase. A phase-separation system is employed to decant the heavier, ethylene dichloride phase from an aqueous phase containing residual reactants and by-products. Additional purification steps, such as washing with substantially anhydrous monoethylene glycol, further remove water, acids, and 2-chloroethanol, producing high-purity ethylene dichloride. Recycling unconverted monoethylene glycol and 2-chloroethanol to the reactor increases overall conversion and enhances process economics.