Diester Preparation with Staged Pressure and Temperature Control

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Solution Overview

Problem

Existing methods for preparing diester-based materials face challenges in improving productivity while minimizing energy consumption and achieving desired conversion rates, particularly in continuous processes involving multiple reactors.

Innovation Solution

A continuous preparation process is employed, where n reaction units are connected in series, with controlled operating pressures and temperatures, starting at high pressure and temperature in the first reactor and gradually reducing pressure and increasing temperature towards the rear end, to optimize reaction rates and minimize energy use.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If multiple esterification reactors are connected in series with increasing temperature in each reactor, then conversion rate is improved, but energy consumption increases

Engineering Contradiction:
Improveconversion rateVSAvoidenergy consumption
Core Design Contradiction:
Manufacturing precisionVSUse of energy by moving object

Solution Approach 1:

The patent applies parameter changes by controlling the operating pressure of the first reactor at 0.4 kg/cm², which is higher than conventional processes. This pressure parameter change allows the reaction to proceed efficiently without requiring progressively higher temperatures in subsequent reactors, thereby reducing overall energy consumption while maintaining high conversion rates.

Inventive Principle:
Principle #35Parameter changes

2Productivity

If operating pressure is reduced from second reactor to nth reactor in series, then productivity is improved, but reaction rate control becomes more difficult

Engineering Contradiction:
ImproveproductivityVSAvoidreaction rate control
Core Design Contradiction:
ProductivityVSEase of operation

Solution Approach 1:

The patent divides the esterification process into multiple reaction units connected in series, with each unit having specific pressure control. The first reactor operates at 0.4 kg/cm², and subsequent reactors have progressively reduced pressure. This segmentation allows productivity improvement through continuous flow while maintaining reaction rate control through staged pressure management.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent implements a staged pressure reduction strategy where the first reactor operates at elevated pressure (0.4 kg/cm²) and subsequent reactors operate at progressively lower pressures. This parameter change approach enables both high productivity through continuous processing and effective reaction rate control through differentiated pressure zones across the reaction units.

Inventive Principle:
Principle #35Parameter changes

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 enhances productivity and reduces energy consumption by effectively managing reaction rates and removing by-products, resulting in a more efficient and cost-effective production of diester-based materials like dioctyl terephthalate.

Implementation Method 1

a reaction unit including a reactor which esterifies dicarboxylic acid and alcohol

Methodology Applied
Scientific EffectEsterification: Chemical Bonding

Implementation Method 2

an operating temperature of the reactor is increased toward the reaction unit at a rear end, thereby controlling a reaction rate

Methodology Applied
Scientific EffectTemperature control: Heating

Implementation Method 3

an operating pressure of the reactor of the first reaction unit is 0.4 kg/cm²

Methodology Applied
Scientific EffectPressure control: Pressure Increase

Data Source

PatentEP4023628B1Method for preparing diester-based material
Publication Date: 2025.12.24 LG CHEM LTD
  • EP4023628B1 patent drawingFigure 1~2

AI summary

Provided is a method of preparing a diester-based material, and more particularly, a method of preparing a diester-based material, which is carried out by a continuous preparation process of a diester-based material including a reaction part in which a total of n reaction units from a first reaction unit to an nth reaction unit are connected in series, the reaction unit including a reactor which esterifies dicarboxylic acid and alcohol, includes: esterifying dicarboxylic acid and alcohol in a reactor of the first reaction unit to produce a reaction product, and supplying a lower discharge stream including the reaction product to a reaction unit at a rear end, wherein an operating pressure of the reactor of the first reaction unit is 0.4 kg/cm2G to 5.5 kg/cm2G, an operating pressure is reduced from a reactor of any one reaction unit of reaction units from a second reaction unit to the nth reaction unit to a reactor of the nth reaction unit, and an operating temperature is increased from the reactor of the first reaction unit to the reactor of the nth reaction unit.