Molecular Sieve Synthesis via Morphology Modifiers
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Solution Overview
Problem
There is a need for improved molecular sieves with enhanced catalytic activity and selectivity, particularly in hydrocarbon conversion reactions, where existing molecular sieves have limitations in crystal size, external surface area, and acidity, which affect their performance.
Innovation Solution
A process for preparing molecular sieve crystals with specific framework codes, involving the use of a morphology modifier to influence crystal growth, resulting in smaller crystal sizes and increased external surface area and acidity, thereby enhancing catalytic activity and selectivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If conventional molecular sieve synthesis is used, then crystal formation is achieved, but crystal size is large with limited external surface area and catalytic activity
Solution Approach 1:
The patent applies parameter changes by modifying the synthesis conditions through pH adjustment and addition of specific cations (Na+, K+, Cs+) to control crystal growth. By changing the pH to alkaline conditions and introducing different cations, the crystal size is reduced while increasing external surface area, thereby resolving the contradiction between crystal size and surface area
Solution Approach 2:
The patent applies local quality by creating non-uniform distribution of cations and pH conditions within the synthesis mixture. Different regions of the crystallization process have different local conditions that promote formation of smaller crystals with higher external surface area, rather than uniform large crystals
2Productivity
If conventional molecular sieve synthesis is used, then crystal formation is achieved, but catalytic activity and selectivity are limited
Solution Approach 1:
The patent changes synthesis parameters including pH adjustment to alkaline conditions and addition of specific cations to enhance catalytic activity. These parameter modifications improve catalytic performance while maintaining relatively simple synthesis procedures, resolving the contradiction between catalytic activity and ease of manufacture
Solution Approach 2:
The patent uses cations (Na+, K+, Cs+) as intermediaries that mediate the synthesis process. These cations facilitate crystal formation under modified conditions that enhance catalytic activity, acting as mediators between the synthesis process and the desired catalytic properties
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 process produces molecular sieves with increased external surface area and acidity, leading to improved catalytic activity and selectivity in hydrocarbon conversion reactions, such as dewaxing and alkylation processes.
Implementation Method 1
A process of preparing crystals of a molecular sieve... combining at least a source of a tetravalent element X, a morphology modifier L, and water to form a synthesis mixture; heating said synthesis mixture under crystallization conditions
Implementation Method 2
heating said synthesis mixture under crystallization conditions for a time of about 1 hour to 100 days to form the crystals of the molecular sieve
Data Source
AI summary
Processes are provided for preparing molecular sieves of framework structure MEI, TON, MRE, MWW, MFS, MOR, FAU, EMT, or MSE. The process involves preparing a synthesis mixture for the molecular sieve wherein the synthesis mixture includes a morphology modifier L selected from the group consisting of cationic surfactants having a quaternary ammonium group comprising at least one hydrocarbyl group having at least 12 carbon atoms, nonionic surfactants, anionic surfactants, sugars and combinations thereof.