Composite Solid Acid Catalyst for Alkylation
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Solution Overview
Problem
Existing solid acid catalysts have a significantly lower acid sites density compared to liquid acids, limiting their effectiveness in hydrocarbon conversion reactions such as alkylation due to structural restrictions, and they primarily consist of Brönsted acid sites with less homogeneous acid strength distribution.
Innovation Solution
A composite solid acid catalyst is developed by loading an inorganic acid onto a porous inorganic support with a heteropoly compound, creating a higher density of Brönsted acid sites through the absorption of inorganic acids into the accumulation space formed by heteropoly compound anions, achieving an acid sites density of not less than 1.4×10−3 mol H+/g with homogeneous acid strength distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If solid acid catalysts are used instead of liquid acids, then structural restrictions are imposed on the catalyst form, but the acid sites density decreases significantly
Solution Approach 1:
The invention uses a composite structure combining heteropoly compounds (providing acid sites) with porous inorganic supports (providing surface area and porosity). This composite approach allows the catalyst to maintain solid form while achieving high acid sites density through the synergistic combination of materials with complementary properties
Solution Approach 2:
The invention employs porous inorganic supports with controlled pore structures to load heteropoly compounds. The porous structure provides large internal surface area and accumulation spaces that enable high loading of acid-containing compounds, thereby increasing acid sites density while maintaining the solid catalyst form
2Quantity of substance
If conventional solid acid catalysts are used, then Brönsted acid sites are provided, but the acid strength distribution is not homogeneous
Solution Approach 1:
The invention creates different functional zones within the catalyst structure: heteropoly compounds provide strong Brönsted acid sites in specific regions, while the porous support matrix provides a distributed framework. This local differentiation allows optimization of acid strength distribution and type in different parts of the catalyst
Solution Approach 2:
The invention modifies the acid strength parameters by selecting specific heteropoly compounds with controlled acidities and adjusting their loading amounts on the support. This parameter optimization enables achievement of both high acid sites density and homogeneous acid strength distribution
3Quantity of substance
If heteropoly compounds are loaded onto porous supports, then acid sites density can be increased, but the complexity of catalyst preparation increases
Solution Approach 1:
The invention performs preliminary treatment of the porous support by controlling its porosity and surface properties before loading heteropoly compounds. This preliminary preparation optimizes the support structure in advance, simplifying the subsequent loading process and improving the final catalyst performance
Solution Approach 2:
The porous inorganic support acts as an intermediary carrier that facilitates the loading and distribution of heteropoly compounds. The support's porous structure serves as a mediator to achieve uniform distribution and high loading capacity while simplifying the overall preparation process
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 composite catalyst exhibits a higher acid sites density and homogeneous acid strength distribution, enhancing catalytic activity and selectivity in alkylation reactions, surpassing the performance of conventional solid acid catalysts by an order of magnitude.
Implementation Method 1
the inorganic acids dissolved in the inert hydrocarbons and having a small molecular size can be absorbed into the accumulation space formed by the heteropoly compound anions
Data Source
AI summary
The present invention provides a composite solid acid catalyst consisting of from 50%-80% by weight of a porous inorganic support, from 15% to 48% by weight of a heteropoly compound loaded thereon, and from 2% to 6% by weight of an inorganic acid. The present invention further provides a process for preparing said composite solid acid catalyst and a process for conducting an alkylation reaction by using such catalyst. The composite solid acid catalyst of the present invention has the acid sites type of Brönsted acid and has an acid sites density of not less than 1.4×10−3 mol H+/g. Moreover, said composite solid acid catalyst has the homogeneous acid strength distribution, and is a solid acid catalyst having excellent performances.