1,2-Propanediol Preparation with Palladium Formic Acid Decomposition
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Solution Overview
Problem
The existing methods for producing 1,2-propanediol result in the formation of formic acid as a by-product, which leads to corrosion issues in subsequent distillation steps for recovering valuable products like dipropylene glycol and tripropylene glycol.
Innovation Solution
A method involving the use of a palladium catalyst to decompose formic acid in the aqueous phase separated from the reaction mixture, reducing corrosion problems by contacting the aqueous phase with the catalyst without adding hydrogen.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If formic acid is formed as a by-product in the reaction of propene with hydrogen peroxide, then the production of 1,2-propanediol is achieved, but corrosion problems occur in subsequent distillation steps
Solution Approach 1:
The patent applies preliminary action by decomposing formic acid through catalytic decomposition before the distillation process. A catalyst (such as calcium oxide, magnesium oxide, or aluminum oxide) is introduced in step (c) to break down formic acid into carbon monoxide and hydrogen, eliminating the corrosive substance before it can cause damage in subsequent high-temperature distillation steps for recovering 1,2-propanediol and other valuable products.
2Productivity
If formic acid accumulates in the aqueous phase, then the reaction proceeds efficiently, but corrosion damage increases in subsequent processing steps
Solution Approach 1:
The patent converts the harmful effect of formic acid into a beneficial outcome by using its decomposition reaction. The formic acid that would otherwise cause corrosion is transformed through catalytic decomposition into less harmful substances (carbon monoxide and hydrogen), thereby eliminating the reliability issue while maintaining reaction efficiency. This transforms a harmful by-product into a manageable intermediate that can be safely processed.
3Productivity
If high temperature distillation is used to recover 1,2-propanediol, then product recovery is efficient, but corrosion from formic acid is exacerbated
Solution Approach 1:
The patent applies preliminary action by performing catalytic decomposition of formic acid before the high-temperature distillation process. By introducing a catalyst in step (c) to decompose formic acid into carbon monoxide and hydrogen, the harmful corrosive substance is eliminated before the distillation step, allowing efficient product recovery without the exacerbating effect of formic acid corrosion at high temperatures.
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 method effectively decomposes formic acid, mitigating corrosion issues and improving the recovery process for 1,2-propanediol and other valuable products.
Implementation Method 1
contacting at least a part of the aqueous phase (Pa) separated in step b) with a palladium catalyst to provide a treated aqueous phase
Data Source
AI summary
A method for preparing 1,2-propanediol involves reacting propene with hydrogen peroxide in the presence of a catalyst mixture, containing a phase transfer catalyst and a heteropolytungstate, in a liquid reaction mixture containing an aqueous phase with a maximum apparent pH of 6 and an organic phase. The method then involves separating the reaction mixture into an aqueous phase (Pa) containing 1,2-propanediol and formic acid and an organic phase (Po); recycling at least part of the separated organic phase (Po) to the reaction; contacting at least a part of the separated aqueous phase (Pa) with a palladium catalyst; and recovering 1,2 propanediol from the aqueous phase provided by the contacting. The contacting of at least a part of the separated aqueous phase (Pa) with the palladium catalyst reduces the content of formic acid.