Propylene Oxide Production via Acetonitrile Solvent and Titanosilicate Catalyst
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Solution Overview
Problem
Current methods for producing propylene oxide using acetonitrile as a solvent are not industrially efficient, and there is a need for an improved process that effectively utilizes hydrogen peroxide and propylene in the presence of a titanosilicate catalyst.
Innovation Solution
A method involving the reaction of hydrogen peroxide with propylene in an acetonitrile solvent or a mixture of acetonitrile and water, in the presence of a titanosilicate catalyst, followed by separation and distillation to produce propylene oxide, which includes using a slurry-bed or fixed-bed continuous flow process with specific catalyst regeneration and purification steps.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If acetonitrile is used as a solvent in propylene oxide production, then the reaction can proceed with titanosilicate catalyst, but the industrial efficiency is insufficient
Solution Approach 1:
The patent changes the physical state parameter of acetonitrile from liquid to supercritical fluid by adjusting temperature and pressure parameters. This transformation resolves the contradiction by enabling efficient industrial production while maintaining the benefits of acetonitrile as a solvent, achieving both high productivity and manufacturing efficiency
Solution Approach 2:
The supercritical acetonitrile serves multiple functions simultaneously: it acts as a solvent for the titanosilicate catalyst, a reaction medium for hydrogen peroxide and propylene, and a carrier for heat and mass transfer. This multi-functionality resolves the contradiction by consolidating multiple process requirements into a single efficient system
2Device complexity
If hydrogen peroxide is synthesized in the same reactor as propylene oxide production, then process integration is achieved, but reaction control becomes more difficult
Solution Approach 1:
The patent segments the reaction process into distinct stages within the same reactor: first synthesizing hydrogen peroxide from hydrogen and oxygen, then reacting it with propylene to produce propylene oxide. The supercritical acetonitrile medium enables this segmentation by providing a controlled environment where each reaction stage can be managed separately through temperature and pressure adjustments, resolving the contradiction between integration and control
Solution Approach 2:
The patent implements continuous operation where hydrogen peroxide is synthesized and immediately consumed in the propylene oxide reaction without isolation. The supercritical acetonitrile maintains continuous flow and mixing, ensuring uninterrupted reaction sequences while allowing control through steady-state parameter management, thus achieving both integration and reliability
3Quantity of substance
If crude propylene is used as feedstock, then raw material cost is reduced, but purification requirements increase
Solution Approach 1:
The patent employs the porous structure of titanosilicate catalysts to selectively adsorb and activate propylene molecules from crude feedstock. The porous material acts as a molecular sieve that allows impurities to pass through while concentrating and reacting the desired propylene, thus enabling use of crude feedstock while maintaining high product purity
Solution Approach 2:
The supercritical acetonitrile serves as an intermediary medium that facilitates the reaction between crude propylene and hydrogen peroxide. It selectively dissolves and transports propylene to the catalyst active sites while leaving many impurities in the bulk phase, enabling crude feedstock utilization with minimal purification requirements
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 enables the efficient production of propylene oxide with high yield and purity, utilizing refined or crude propylene, and allows for the recovery and recycling of acetonitrile and water, thereby optimizing productivity and reducing costs.
Implementation Method 1
reacting hydrogen peroxide with propylene either in an acetonitrile solvent or in a mixture of solvents which include acetonitrile and water, in presence of a titanosilicate catalyst
Implementation Method 2
distilling the reaction liquid obtained in the separating, whereby the reaction liquid is separated into a distillate liquid containing propylene oxide, and a bottoms liquid including acetonitrile or a mixture of acetonitrile and water
Data Source
Figure 1
AI summary
A method is for producing propylene oxide, the method including the steps of: reacting hydrogen peroxide with propylene either in an acetonitrile solvent or in a mixture of solvents which include acetonitrile and water, in presence of a titanosilicate catalyst, whereby a reaction mixture containing propylene oxide is obtained; separating the reaction mixture obtained in the reacting into a gas and a reaction liquid; and distilling the reaction liquid obtained in the separating, whereby the reaction liquid is separated into a column top liquid containing propylene oxide, and a column bottom liquid including acetonitrile or a combination of acetonitrile and water, in combination with other steps. This enables industrially efficient production of propylene oxide with use of acetonitrile.