Terephthalic Acid Production Using Ionic Liquid Solvents
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Solution Overview
Problem
Current processes for producing terephthalic acid from para-xylene are costly and time-consuming, requiring multiple purification steps and often involve catalytic hydrogenation, while also producing terephthalic acid compositions with undesirable contaminant ratios.
Innovation Solution
A process involving the oxidation of para-xylene with a mixture of a carboxylic acid solvent, a dialkyl imidazolium ionic liquid, and a catalyst such as cobalt or manganese, which produces solid terephthalic acid compositions with controlled contaminant levels, including 4-carboxybenzaldehyde and para-toluic acid, without the need for catalytic hydrogenation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional oxidation processes are used to produce terephthalic acid, then high conversion is achieved, but multiple purification steps and catalytic hydrogenation are required, increasing cost and time
Solution Approach 1:
The invention changes the chemical parameters of the oxidation process by using ionic liquids as catalysts and adjusting the oxidation conditions (temperature, pressure, oxygen flow rate) to produce terephthalic acid with significantly reduced 4-CBA content, eliminating the need for subsequent hydrogenation steps and simplifying purification
Solution Approach 2:
The invention replaces expensive and time-consuming catalytic hydrogenation processes with a simpler purification method using activated carbon treatment and filtration, which is more cost-effective and faster while achieving the same purification goal
2Manufacturing precision
If conventional processes are used, then terephthalic acid is produced, but contaminant ratios (4-CBA, para-toluic acid) are undesirable, requiring additional purification
Solution Approach 1:
By changing the oxidation parameters (using ionic liquids, adjusting temperature and pressure), the invention directly produces terephthalic acid with low contaminant levels, simplifying the purification process to basic filtration and activated carbon treatment
Solution Approach 2:
The invention extracts and removes specific contaminants (4-CBA and para-toluic acid) through selective oxidation conditions and simple filtration processes, achieving high purity without complex multi-step purification
3Manufacturing precision
If catalytic hydrogenation is used to reduce contaminants, then product purity increases, but process cost and time increase
Solution Approach 1:
The invention replaces expensive catalytic hydrogenation with a simpler, more cost-effective method using activated carbon treatment and filtration, which achieves the same contaminant reduction without requiring hydrogen gas, catalysts, or complex equipment
Solution Approach 2:
The invention substitutes the mechanical/chemical complex process of catalytic hydrogenation with a simpler physical process of adsorption and filtration, reducing process complexity while maintaining effectiveness
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 process results in terephthalic acid compositions that are less costly and time-consuming to purify, with reduced contaminant levels, enabling the production of polymer-grade terephthalic acid without hydrogenation steps and simpler purification processes.
Implementation Method 1
oxidizing the para-xylene by contacting the mixture with an oxidizing agent at oxidizing conditions to produce a solid oxidation product comprising terephthalic acid
Implementation Method 2
a catalyst such as cobalt or manganese
Data Source
AI summary
A solid terephthalic acid composition and a process for producing terephthalic acid from para-xylene. The process comprises forming a mixture comprising the para-xylene, a solvent, a bromine source, and a catalyst; and oxidizing the para-xylene by contacting the mixture with an oxidizing agent at oxidizing conditions to produce a solid oxidation product comprising terephthalic acid, para-toluic acid, 4-carboxybenzaldehyde. The solvent comprises a carboxylic acid having from 1 to 7 carbon atoms and an dialkyl imidazolium ionic liquid; and the catalyst comprises at least one of cobalt, titanium, manganese, chromium, copper, nickel, vanadium, iron, molybdenum, tin, cerium, and zirconium. The solid terephthalic acid composition comprises, less than about 4,000 ppm-wt 4-carboxybenzaldehyde content, and more than about 2,000 ppm-wt a para-toluic acid.