Aromatic Hydrocarbon Oligomerization for Narrow Molecular Weight Control

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Solution Overview

Problem

Existing methods for preparing mesophase pitch using pure aromatic hydrocarbon compounds lack control over molecular weight and molecular weight distribution, resulting in poor homogeneity and viscosity fluctuations during spinning, which hinders the production of high-quality carbon fiber products.

Innovation Solution

A preparation method involving an oligomerization reaction of aromatic hydrocarbon compounds using chloroaluminate ionic liquid as a catalyst in a chlorinated hydrocarbon solvent system, which inhibits side reactions and ensures a narrow molecular weight distribution and simple composition of the aromatic hydrocarbon oligomers.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If conventional catalysts (anhydrous aluminum trioxide, solid super acid) are used for oligomerization, then the reaction can proceed at relatively low temperatures, but the molecular weight distribution of the aromatic hydrocarbon oligomers becomes broad and composition becomes complex

Engineering Contradiction:

Improveoligomerization reaction temperatureVSAvoidmolecular weight distribution control

Core Design Contradiction:

TemperatureVSManufacturing precision

Solution Approach 1:

The patent changes the chemical parameters of the catalyst system by using chloroaluminate ionic liquid with specific composition ratios (AlCl3/HR ratio of 1.5-2.5) and adding specific additives (carboxylic acid or phenolic compound) to precisely control the oligomerization reaction, achieving narrow molecular weight distribution while maintaining moderate reaction temperature

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent introduces specific additives (carboxylic acid or phenolic compound) as intermediaries that mediate between the chloroaluminate ionic liquid catalyst and the aromatic hydrocarbon compound, controlling the reaction pathway to produce oligomers with concentrated molecular weight distribution and simple composition

Inventive Principle:

Principle #24Intermediary (Mediator)

2Ease of manufacture

If existing preparation methods are used, then the process is simple and straightforward, but the homogeneity of the mesophase pitch is poor and viscosity fluctuation is large during spinning

Engineering Contradiction:

Improvepreparation process simplicityVSAvoidmesophase pitch homogeneity

Core Design Contradiction:

Ease of manufactureVSStability of the object's composition

Solution Approach 1:

The patent modifies the catalyst system parameters by using chloroaluminate ionic liquid with controlled AlCl3/HR ratio and adding specific additives, which fundamentally changes the oligomerization pathway to produce more uniform oligomers, thereby improving mesophase pitch homogeneity while maintaining process simplicity

Inventive Principle:

Principle #35Parameter changes

3Temperature

If existing preparation methods are used, then the reaction conditions are relatively mild, but the molecular weight distribution is broad leading to spinning instability

Engineering Contradiction:

Improvereaction temperatureVSAvoidspinning process stability

Core Design Contradiction:

TemperatureVSReliability

Solution Approach 1:

The patent optimizes multiple parameters including catalyst composition (AlCl3/HR ratio of 1.5-2.5), additive types (carboxylic acid or phenolic compound), and their ratios to achieve concentrated molecular weight distribution of oligomers, which ensures spinning process stability while maintaining moderate reaction temperature

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

The method produces aromatic hydrocarbon oligomers with narrow molecular weight distribution and simple composition, leading to high-quality mesophase pitch with improved homogeneity and stability for continuous spinning, thereby enhancing the quality of carbon fiber production.

Implementation Method 1

subjecting an aromatic hydrocarbon compound to an oligomerization reaction under catalysis of a chloroaluminate ionic liquid to obtain the aromatic hydrocarbon oligomer

Methodology Applied

Scientific EffectCatalysis: Catalysis

Data Source

PatentUS20260070861A1Preparation method of aromatic hydrocarbon oligomer

Publication Date: 2026.03.12 CHINA UNIV OF PETROLEUM (BEIJING)

AI summary

The present application provides a preparation method of an aromatic hydrocarbon oligomer, the preparation method including: subjecting an aromatic hydrocarbon compound to an oligomerization reaction under the catalysis of a chloroaluminate ionic liquid to obtain the aromatic hydrocarbon oligomer, where the oligomerization reaction is carried out in a solvent system, and the solvent is selected from chlorinated hydrocarbon solvents, and the aromatic hydrocarbon compound is selected from fused-ring aromatic hydrocarbons with 2 to 4 rings. The preparation method of the present application can efficiently prepare aromatic hydrocarbon oligomers with simple composition and narrow molecular weight distribution under mild conditions, thereby providing a high-quality precursor for the preparation of high-quality mesophase pitch.