Mixed-Phase Alumina HCl Oxidation Catalyst Against Pulverization

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Solution Overview

Problem

Existing hydrogen chloride oxidation catalysts suffer from pulverization after long-term use, which leads to clogging and reduced chlorine production efficiency.

Innovation Solution

A hydrogen chloride oxidation catalyst comprising alumina as a carrier with supported copper, alkali metal, and rare-earth elements, characterized by specific X-ray diffraction peak ratios, surface area, pore diameter, and particle size, which enhances catalytic activity and stability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Duration of action of stationary object

If a hydrogen chloride oxidation catalyst is used for a long period, then chlorine production continues, but the catalyst shape collapses and pulverizes

Engineering Contradiction:
Improvecatalyst service lifeVSAvoidcatalyst shape stability
Core Design Contradiction:
Duration of action of stationary objectVSStability of the object's composition

Solution Approach 1:

The patent applies parameter changes by precisely controlling the calcination temperature (550-980°C) and time to transform γ-alumina into a mixed-phase structure containing both γ-alumina and α-alumina. This phase transformation changes the physical and chemical parameters of the carrier, resulting in enhanced mechanical strength and resistance to pulverization while maintaining catalytic activity over extended periods

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite material structure by forming a mixed-phase alumina carrier containing both γ-alumina and α-alumina phases. The γ-alumina provides high surface area and catalytic activity, while the α-alumina provides structural stability and resistance to collapse. This composite phase structure resolves the contradiction between maintaining catalyst shape and extending service life

Inventive Principle:
Principle #40Composite materials

2Productivity

If the catalyst activity is increased to improve chlorine yield, then production efficiency improves, but the catalyst may become more prone to pulverization

Engineering Contradiction:
Improvechlorine yieldVSAvoidcatalyst stability
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent applies local quality by creating distinct functional zones within the catalyst structure: the γ-alumina phases provide high surface area and catalytic activity for chlorine production, while the α-alumina phases provide structural support and mechanical stability. The supported metal components (copper, alkali metal, rare-earth element) are localized on the carrier surface where they can maximize catalytic effect without compromising overall structural integrity

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent uses composite materials by combining multiple metal components (copper, alkali metal, and rare-earth element) on the mixed-phase alumina carrier. This composite formulation enhances catalytic activity for hydrogen chloride oxidation while the stable α-alumina phase in the carrier prevents pulverization, thus achieving both high productivity and reliability

Inventive Principle:
Principle #40Composite materials

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 catalyst effectively suppresses pulverization and maintains high catalytic activity over extended periods, improving chlorine yield and production efficiency.

Implementation Method 1

a hydrogen chloride oxidation catalyst for oxidizing hydrogen chloride, the hydrogen chloride oxidation catalyst including: a carrier containing alumina as a main component; and copper, an alkali metal, and a rare-earth element, all of which are supported on the carrier

Methodology Applied
Scientific EffectCatalysis: Catalysis

Implementation Method 2

in an X-ray diffraction pattern measured with an X-ray diffractometer using CuKα rays

Methodology Applied
Scientific EffectX-ray diffraction: X-Ray

Data Source

PatentEP4678286A1Hydrogen chloride oxidation catalyst and method for manufacturing hydrogen chloride oxidation catalyst
Publication Date: 2026.01.14 MITSUI CHEMICALS INC
  • EP4678286A1 patent drawingFigure 1~2
  • EP4678286A1 patent drawingFigure 3
  • EP4678286A1 patent drawingFigure 4

AI summary

A hydrogen chloride oxidation catalyst is a catalyst for oxidizing hydrogen chloride. The hydrogen chloride oxidation catalyst includes a carrier, and also copper, an alkali metal, and a rare-earth element. The carrier contains alumina as a main component. The copper, the alkali metal, and the rare-earth element are supported on the carrier. In an X-ray diffraction pattern measured with an X-ray diffractometer using CuKα rays, the ratio of a peak at 2θ = 65.2° in the X-ray diffraction pattern with respect to a peak intensity of a (440) plane of alumina crystal is 0.0015 or more and 0.500 or less.