Acetaminophen Flow Synthesis via Monolith Catalyst
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Solution Overview
Problem
Existing methods for producing acetaminophen face challenges with high reaction temperatures and pressures, leading to difficulties in control, equipment costs, and potential catalyst degradation, necessitating a safer, more productive, and cost-effective continuous production method.
Innovation Solution
A method involving a supported metal catalyst on a monolith porous body, where p-nitrophenol is reacted with an acetylating agent and hydrogen at low temperatures (0° C. to 60° C.) and pressures (0.1 MPa to 1 MPa), utilizing a flow synthesis system to efficiently produce acetaminophen with high selectivity and yield.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a batch reaction method with high temperature is used to produce acetaminophen, then the reaction proceeds rapidly, but control of the reaction becomes difficult due to intense heat generation
Solution Approach 1:
The patent applies continuous flow reaction instead of batch reaction. The reaction mixture continuously flows through the catalyst-packed column, maintaining steady-state conditions that prevent heat accumulation and enable better temperature control while sustaining high productivity.
Solution Approach 2:
The patent replaces the need for external heating/cooling control mechanisms by using the flow system's inherent heat dissipation. The continuous flow of reaction mixture through the catalyst column provides automatic thermal management, substituting complex thermal control systems with a simpler flow-based approach.
2Productivity
If continuous reaction method with high pressure and high temperature is used, then productivity is increased, but equipment cost increases and catalyst degradation occurs
Solution Approach 1:
The patent changes the reaction parameters from high temperature and high pressure to moderate temperature (20-100°C) and atmospheric or mild pressure conditions. This is achieved by optimizing the catalyst system and continuous flow conditions, allowing productivity to be maintained while dramatically reducing equipment requirements and costs.
Solution Approach 2:
The patent uses a stable, reusable catalyst in a continuous flow system that operates under mild conditions. The catalyst remains intact and active for extended periods without requiring expensive high-pressure equipment, effectively replacing the need for costly specialized equipment with a simpler, more economical system.
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 enables continuous production of acetaminophen safely and inexpensively with high selectivity and good yield under mild conditions, reducing equipment costs and minimizing catalyst degradation, while avoiding the need for high-pressure equipment.
Implementation Method 1
a method in which p-nitrophenol, acetic acid, and a metal catalyst are added to a reaction vessel, hydrogen is added thereto, and a reaction is caused to take place at a high temperature to produce acetaminophen
Implementation Method 2
p-nitrophenol is added to an acetic anhydride/acetic acid solution to form a solution, and the solution is passed through a column packed with a noble metal catalyst, specifically, a Pd/C catalyst, to cause the p-nitrophenol to undergo a reaction at a hydrogen pressure of 8 MPa to 10 MPa
Data Source
AI summary
A method for producing acetaminophen, the method comprising causing p-nitrophenol to undergo an acetamination reaction to produce the acetaminophen, by passing a solution containing the p-nitrophenol through a column packed with a catalyst while also passing an acetylating agent and hydrogen through the column. The catalyst is a supported metal catalyst in which a metal element is supported on a monolith porous body, and a reaction temperature of the acetamination reaction is 0° C. to 60° C., and a reaction pressure of the acetamination reaction is 0.1 MPa to 1 MPa.