SSZ-13 Synthesis Using Choline Cation Template

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Solution Overview

Problem

The high cost and toxicity of structure-directing agents like N,N,N-trimethyl-1-amantadine and benzyl trimethyl quaternary ammonium ion limit the commercial production and application of molecular sieve SSZ-13, which has a CHA topological structure.

Innovation Solution

A method for synthesizing crystalline molecular sieve SSZ-13 using choline cations and/or SSZ-13 seed crystals as structure-directing agents, eliminating the need for expensive and toxic agents, and involving a reaction mixture of tetravalent silicon, trivalent aluminum, alkali metal compounds, and hydroxide ions under controlled crystallization conditions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If N,N,N-trimethyl-1-amantadine (TMAA+) is used as a structure-directing agent, then the molecular sieve SSZ-13 can be synthesized with proper crystal structure, but the synthesis cost becomes rather high

Engineering Contradiction:

Improvecrystal structure qualityVSAvoidsynthesis cost

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent replaces the expensive TMAA+ structure-directing agent with choline cation, which is a low-cost alternative. The choline cation effectively directs the formation of SSZ-13 crystal structure while being significantly cheaper, thus resolving the contradiction between crystal structure quality and synthesis cost.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The patent changes the chemical parameter of the structure-directing agent from TMAA+ to choline cation. This parameter change maintains the ability to direct crystal formation while dramatically reducing the cost, as choline is a much more economical reagent.

Inventive Principle:

Principle #35Parameter changes

2Ease of manufacture

If benzyl trimethyl quaternary ammonium ion (BzTMA+) is used as a structure-directing agent, then the synthesis cost is reduced, but it has irritation and harmful effect on humans

Engineering Contradiction:

Improvesynthesis costVSAvoidtoxicity and irritation

Core Design Contradiction:

Ease of manufactureVSObject-affected harmful factors

Solution Approach 1:

The patent selects choline cation as the structure-directing agent, which is not only low-cost but also non-toxic and safe for human handling. Choline is a biocompatible substance commonly found in nature, thus eliminating the harmful effects associated with BzTMA+ while maintaining cost-effectiveness.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The patent transforms the selection criteria by choosing a substance (choline) that is inherently safe and beneficial, rather than merely selecting the cheapest option. Choline's biocompatibility and safety profile turn what could be a harmful substitution into a beneficial one, resolving the contradiction between cost reduction and safety.

Inventive Principle:

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

3Ease of manufacture

If benzyl quaternary ammonium ions are added to reduce TMAA+ dose, then the cost is reduced, but the expensive TMAA+ cation is still used

Engineering Contradiction:

Improvesynthesis costVSAvoiddependence on expensive TMAA+

Core Design Contradiction:

Ease of manufactureVSQuantity of substance

Solution Approach 1:

The patent extracts TMAA+ completely from the synthesis system and replaces it entirely with choline cation. This complete substitution eliminates any dependence on the expensive TMAA+ cation, achieving full cost reduction without requiring any amount of the expensive reagent.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The choline cation serves as a universal structure-directing agent that can fully replace TMAA+ in directing SSZ-13 crystal formation. This multi-functional choline cation performs the same structure-directing role as TMAA+ but at a fraction of the cost, eliminating the need for any TMAA+ in the synthesis.

Inventive Principle:

Principle #6Universality (Multi-functionality)

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 method produces high-quality SSZ-13 with reduced production costs and toxicity, enabling broader industrial applications and improved hydrothermal stability due to the use of a low-cost and non-toxic structure-directing agent, choline cation.

Implementation Method 1

bringing the following raw materials into contact in water under a crystallization condition: (1) at least one tetravalent silicon source; (2) at least one trivalent aluminium source; (3) at least one alkali metal compound; (4) choline cations and/or SSZ-13 seed crystals; and (5) hydroxide ions

Methodology Applied

Scientific EffectCrystallisation: Crystallisation

Data Source

PatentUS9962688B2Method for synthesizing molecular sieve SSZ-13

Publication Date: 2018.05.08 BEIJING UNIV OF CHEM TECH

AI summary

A method for synthesizing a crystalline molecular sieve SSZ-13, characterized in that the method comprises bringing the following raw materials into contact in water under a crystallization condition: at least one tetravalent silicon source, at least one trivalent aluminum source, at least one alkali metal compound, choline cations and/or SSZ-13 seed crystals, and hydroxide ions. The method avoids using benzyl trimethyl quaternary ammonium ions (BzTMA+) or N,N,N-trimethyl-1-amantadine cations as structure-directing agents, and obtains high-quality crystal molecular sieve SSZ-13. Due to the use of a low-cost nontoxic structure-directing agent, the method has low production price by employing a low-cost nontoxic template, and can be popularized for application.