HMCM-22 Catalyst Heteroatom Modification for Alkylbenzene Stability

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Solution Overview

Problem

The production of long-chain alkylbenzenes using solid acid catalysts faces issues such as rapid deactivation, difficult regeneration, and insufficient yield and selectivity due to the insufficient stability of the catalysts, particularly during the alkylation process of long-chain olefins and aromatic hydrocarbons.

Innovation Solution

A method involving a HMCM-22 type molecular sieve solid acid catalyst modified with heteroatoms like boron, gallium, or phosphorus, used in conjunction with a coke-burning regeneration process using a gas mixture with controlled oxygen and nitrogen levels, to enhance catalyst stability and performance for producing long-chain alkylbenzenes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If solid acid catalysts are used for alkylation of long-chain olefins and aromatic hydrocarbons, then environmental friendliness and equipment safety are improved, but catalyst stability and continuous running time deteriorate

Engineering Contradiction:

Improveenvironmental pollution and equipment corrosionVSAvoidcatalyst continuous running time

Core Design Contradiction:

Object-affected harmful factorsVSDuration of action of stationary object

Solution Approach 1:

The patent modifies the molecular sieve structure by controlling the Si/Al ratio and introducing heteroatom modifications to change the catalyst's acid site distribution and strength. This parameter optimization enhances catalyst stability and extends continuous running time while maintaining environmental benefits of solid acid catalysts

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent uses composite molecular sieve structures combining different framework compositions and heteroatom modifications to create a catalyst with improved stability. The composite structure integrates multiple functional components that work synergistically to prevent deactivation and extend operational duration

Inventive Principle:

Principle #40Composite materials

2Productivity

If conventional solid acid catalysts are used, then catalyst activity is improved, but regeneration difficulty increases

Engineering Contradiction:

Improvecatalyst activityVSAvoidcatalyst regeneration ease

Core Design Contradiction:

ProductivityVSEase of repair

Solution Approach 1:

The patent converts the harmful coke deposits that cause deactivation into a beneficial regeneration mechanism. By designing the catalyst with controlled pore structure and acid site distribution, the coke formation and subsequent combustion become a manageable process that restores catalyst activity without damaging the structure, making regeneration easier and more effective

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

3Reliability

If solid acid catalysts replace liquid acids, then safety and environmental performance are improved, but catalyst selectivity and product yield deteriorate

Engineering Contradiction:

Improvesafety and environmental performanceVSAvoidproduct selectivity and yield

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

The patent creates catalysts with localized acid sites of different strengths by controlling aluminum distribution and heteroatom placement within the molecular sieve framework. This local quality variation allows specific reactions to occur at specific sites, improving selectivity for desired alkylbenzene products while maintaining the safety advantages of solid acid catalysts

Inventive Principle:

Principle #3Local quality

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 allows for stable and high-yield production of long-chain alkylbenzenes with improved selectivity and extended continuous running time, with the regenerated catalyst maintaining performance equivalent to fresh catalysts.

Implementation Method 1

reacting an aromatic hydrocarbon and a long-chain olefin in the presence of a solid acid catalyst

Methodology Applied

Scientific EffectCatalysis: Catalysis

Implementation Method 2

the catalyst is in-situ coke-burning regenerated by using a regeneration gas comprising 1-20 wt % of oxygen

Methodology Applied

Scientific EffectOxidation: Oxidation

Data Source

PatentUS11370722B2Method for producing long-chain alkylbenzene

Publication Date: 2022.06.28 NANJING CHEM CHEM TECH CO LTD

AI summary

The present invention relates to a method for producing long-chain alkylbenzene by reacting an aromatic hydrocarbon and a long-chain olefin, wherein the reaction is carried out in the presence of a solid acid catalyst, the aromatic hydrocarbon is selected from the group consisting of benzene, toluene and xylene, the long-chain olefin is selected from the group consisting of C8-C26 alkenes, the catalyst is a HMCM-22 type molecular sieve solid acid catalyst modified with heteroatom(s), the heteroatom(s) is/are selected from the group consisting of boron, gallium, indium, chromium, molybdenum, tungsten, manganese and phosphorus, and the molar ratio of silicon atoms to heteroatoms in the solid acid catalyst is in the range of 1:0.01-0.03. The invention also relates to a method for regenerating the solid acid catalyst used in the reaction.