Propylene Oxide Epoxidation via H2O2 Impurity Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current processes for preparing propylene oxide using hydrogen peroxide as an oxidizing agent are inefficient due to the negative impact of aliphatic oxygen-containing compounds with 8 to 10 carbon atoms on the catalytic performance of zeolitic catalysts, leading to reduced selectivity and increased temperatures required for high hydrogen peroxide conversion.
Innovation Solution
A process involving a reaction mixture of propylene, water, organic solvent, and hydrogen peroxide, where the concentration of aliphatic oxygen-containing compounds with 8 to 10 carbon atoms is limited to no more than 500 mg per kg, using a zeolitic catalyst with a framework structure comprising Si, O, and Ti, to enhance catalytic performance and maintain high selectivity and conversion efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If hydrogen peroxide is used as oxidizing agent in propylene oxide production, then the process becomes more environmentally friendly and cost-effective, but aliphatic oxygen-containing compounds with 8 to 10 carbon atoms accumulate and reduce catalytic performance
Solution Approach 1:
The patent extracts and removes aliphatic oxygen-containing compounds with 8 to 10 carbon atoms from the reaction mixture through a separation unit. This extraction eliminates the harmful impurities that accumulate during hydrogen peroxide-based epoxidation, thereby maintaining catalytic performance while preserving the simplicity and cost-effectiveness of using hydrogen peroxide as the oxidizing agent.
Solution Approach 2:
The patent introduces a separation unit as an intermediary component between the reactor and the product stream. This intermediary removes the harmful aliphatic oxygen-containing compounds without interfering with the main epoxidation reaction, allowing the process to maintain both simplicity and catalytic reliability simultaneously.
2Ease of operation
If the concentration of aliphatic oxygen-containing compounds is not controlled, then the process operation is simpler, but selectivity and conversion efficiency decrease
Solution Approach 1:
The patent implements a continuous separation process where aliphatic oxygen-containing compounds are continuously removed from the reaction mixture. This continuous action maintains high conversion and selectivity throughout operation without requiring intermittent process adjustments, thus preserving ease of operation while ensuring sustained productivity.
Solution Approach 2:
The patent changes the concentration parameter of aliphatic oxygen-containing compounds by introducing a separation unit that maintains their level below 500 mg per kg of hydrogen peroxide. This parameter control ensures high catalytic performance while the automated nature of the separation keeps operation simple.
3Device complexity
If aliphatic oxygen-containing compounds are present in high concentrations, then the reaction proceeds without additional purification steps, but higher temperatures are required to achieve high conversion
Solution Approach 1:
The patent extracts aliphatic oxygen-containing compounds from the reaction mixture before they can interfere with the epoxidation reaction. By removing these compounds, the process avoids the need for elevated temperatures to compensate for their inhibitory effects, thus reducing energy consumption while maintaining process simplicity.
Solution Approach 2:
The patent performs preliminary removal of harmful impurities through the separation unit before the reaction proceeds. This preliminary action prevents the accumulation of aliphatic oxygen-containing compounds that would otherwise require higher temperatures to overcome, thereby reducing the temperature requirement while avoiding additional purification complexity.
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 the catalyst's performance, achieving high hydrogen peroxide conversion (>98%) and selectivity (>85%) over a prolonged period, while maintaining efficient propylene oxide production by controlling the concentration of aliphatic oxygen-containing compounds, thus optimizing the epoxidation reaction conditions.
Implementation Method 1
contacting the reaction mixture provided in (i) in an epoxidation zone with an epoxidation catalyst comprising a zeolitic material having a framework structure comprising Si, O, and Ti, and subjecting the reaction mixture to epoxidation reaction conditions in the epoxidation zone
Implementation Method 2
making use of hydrogen peroxide (H2O2) as oxidizing agent
Data Source
AI summary
The invention relates in a first aspect to a process for the preparation of propylene oxide, comprising: (i) providing a reaction mixture comprising propylene, water, organic solvent, and hydrogen peroxide; (ii) contacting the reaction mixture provided in (i) in an epoxidation zone with an epoxidation catalyst comprising a zeolitic material having a framework structure comprising Si, O, and Ti, and subjecting the reaction mixture to epoxidation reaction conditions in the epoxidation zone, obtaining, in the epoxidation zone, a mixture comprising propylene oxide, water, and organic solvent; (iii) removing an effluent stream from the epoxidation zone, the effluent stream comprising propylene oxide, water, and organic solvent; wherein the reaction mixture provided in (i) and subjected to (ii) contains in an amount of at most 500 mg per kg hydrogen peroxide comprised in said reaction mixture at least one aliphatic oxygen containing compound having 8 to 10 carbon atoms. The invention further relates in a second aspect to a reaction mixture for preparing propylene oxide, comprising propylene, water, organic solvent, and hydrogen peroxide, wherein the reaction mixture comprises at least one aliphatic oxygen containing compound having 8 to 10 carbon atoms in an amount of at most 500 mg per kg hydrogen peroxide comprised in the reaction mixture. In a third aspect, the invention relates to a system comprising an epoxidation catalyst comprising a zeolitic material having a framework structure comprising Si, O, and Ti, and further comprising the reaction mixture comprising propylene, water, and organic solvent according to the second aspect. In a fourth aspect, the invention relates to the use of an aqueous hydrogen peroxide solution as epoxidation agent for preparing propylene oxide in the presence of an organic solvent and an epoxidation catalyst comprising a zeolitic material having a framework structure comprising Si, O, and Ti, wherein the aqueous hydrogen peroxide solution comprises at least one aliphatic oxygen containing compound having 8 to 10 carbon atoms in an amount of at most 500 mg per kg hydrogen peroxide comprised in the aqueous hydrogen peroxide solution.