Direct Esterification of Terephthalic Acid to DBT
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Solution Overview
Problem
Current methods cannot directly produce di-n-butyl terephthalate (DBT) from terephthalic acid using titanate catalysts, and existing processes face issues with foaming and low reaction efficiency.
Innovation Solution
A process involving the use of excess strong acids like methane sulfonic acid and sulfuric acid in combination with a fractionating column at atmospheric pressure and temperatures of 110° to 220°C to catalyze the reaction of terephthalic acid with butanol, effectively producing DBT with high conversion rates and minimal foaming.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If titanate catalyst is used to catalyze the reaction of terephthalic acid with butanol, then the reaction can proceed, but di-n-butyl terephthalate cannot be produced directly
Solution Approach 1:
The patent changes the catalyst type from titanate to strong acids (methane sulfonic acid, sulfuric acid, methane disulfonic acid, butane sulfonic acid, or perfluorobutane sulfonic acid) and adjusts the reaction conditions (temperature: 110° to 220°C, atmospheric pressure, catalyst concentration: 3% to 10% by weight) to enable direct production of di-n-butyl terephthalate from terephthalic acid and butanol
Solution Approach 2:
The patent introduces a fractionating column as an intermediary device to remove water from the reaction system, which facilitates the esterification reaction and enables the direct production of di-n-butyl terephthalate without foaming problems
2Productivity
If strong acid catalyst is used to produce di-n-butyl terephthalate, then high conversion rates are achieved, but foaming problems occur
Solution Approach 1:
The patent introduces a fractionating column as an intermediary device to remove water from the reaction system. The fractionating column acts as a water removal mechanism that prevents water accumulation, thereby eliminating foaming problems while maintaining high conversion rates
Solution Approach 2:
The patent utilizes phase transition (evaporation and condensation) in the fractionating column to separate water from the reaction mixture. Water is removed through vaporization and condensed in the fractionating column, preventing foaming while maintaining high conversion rates
3Object-generated harmful factors
If fractionating column is added to remove water, then foaming is eliminated, but device complexity increases
Solution Approach 1:
The patent introduces a fractionating column as an intermediary device to remove water from the reaction system. The fractionating column acts as a water removal mechanism that prevents water accumulation, thereby eliminating foaming problems
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 process achieves efficient conversion of terephthalic acid to di-n-butyl terephthalate with high reaction rates and no observable foaming, resulting in a high-quality DBT product.
Implementation Method 1
contacting terephthalic acid with butanol in the presence of a catalyst
Implementation Method 2
the reactor is fitted with a fractionation column for removing water
Data Source
AI summary
Disclosed is a process for the preparation of di-n-butyl terephthalate by the esterification of terephthalic acid with n-butanol in the presence of a strong acid while employing a fractionating column.