Propylene Oxide Production via Mixed Solvent Phase Partitioning
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Solution Overview
Problem
Existing propylene oxide production processes using titanium silicalite-1 (TS-1) catalysts face issues with catalyst deactivation and high methanol usage, leading to energy-intensive separation processes and byproduct formation due to excessive methanol and single-phase reaction conditions.
Innovation Solution
A process utilizing a mixed solvent system with a combination of alcohols and non-reactive co-solvents, where propylene oxide partitions into the organic phase, reducing contact with water and extending catalyst lifetime, and allowing for simpler phase separation and recovery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If large amounts of methanol are used as solvent, then high catalyst activity is achieved, but byproduct formation increases and energy consumption for purification increases
Solution Approach 1:
The patent changes the solvent composition parameters by using a mixed solvent system with specific ratios of methanol (5-50 wt%), water (30-60 wt%), and organic solvent (20-60 wt%). This parameter optimization maintains sufficient catalyst activity while reducing methanol byproduct formation compared to using pure or high-concentration methanol
Solution Approach 2:
The patent employs a composite solvent system combining methanol, water, and organic solvent (such as dichloromethane, chloroform, or toluene). This composite approach leverages the benefits of each component: methanol for catalyst activation, water for safety and cost, and organic solvent for selectivity enhancement and byproduct reduction
2Reliability
If large amounts of methanol are used as solvent, then high catalyst activity is achieved, but energy consumption for separation and purification increases
Solution Approach 1:
The patent optimizes solvent composition parameters to use moderate methanol concentrations (5-50 wt%) combined with water and organic solvents. This reduces the total amount of methanol requiring separation and purification, thereby lowering energy consumption while maintaining adequate catalyst activity
Solution Approach 2:
The patent extracts propylene oxide into the organic solvent phase during the reaction. This phase extraction removes the product from the aqueous-methanol phase where catalyst deactivation and byproduct formation occur, reducing the burden on purification systems and lowering energy consumption
3Stability of the object's composition
If single phase reaction conditions are used, then homogeneous mixture is achieved, but catalyst lifetime decreases
Solution Approach 1:
The patent uses a composite solvent system creating a heterogeneous multiphase reaction medium. The organic solvent forms a separate phase that extracts propylene oxide, preventing catalyst pore clogging and maintaining catalyst lifetime, while the aqueous-methanol phase provides homogeneous distribution of reactants and catalyst
4Reliability
If excessive methanol is used, then high catalyst activity is maintained, but the size of purification towers increases
Solution Approach 1:
The patent changes the solvent composition parameters to use moderate methanol concentrations (5-50 wt%) rather than excessive amounts. This reduces the volume of methanol-containing streams requiring purification, thereby reducing the size of purification towers while maintaining sufficient catalyst activity
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 increases reaction selectivity, extends catalyst life, and reduces energy consumption by minimizing methanol usage and byproduct formation, facilitating efficient separation and recycling of propylene oxide.
Implementation Method 1
propylene oxide partitions into the organic phase, reducing contact with water
Implementation Method 2
reacting propylene and a peroxide compound, in the presence of a catalyst such as a titanium silicalite-1 (TS-1) catalyst
Data Source
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AI summary
A multiple liquid phase composition and process for preparing propylene oxide including a reaction mixture of: (a) propylene, (b) at least one peroxide compound, (c) at least one catalyst, such as a titanium silicalite-1 (TS-I) catalyst, and (d) and a predetermined amount of a solvent mixture; wherein the solvent mixture comprises at least (i) at least one alcohol, such as methanol, and (ii) at least one non-reactive co-solvent; wherein the solvents are mixed at a predetermined concentration; wherein the non-reactive co-solvent has a different boiling point than propylene oxide; and wherein the resulting propylene oxide product partitions into a high affinity solvent during the reaction. The process of the present invention advantageously produces a waste stream with little or no significant amount of sodium chloride (NaCl).