Tin Nitrate Catalyst Preparation Corrosion Control

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Solution Overview

Problem

The use of tin chloride in catalyst production leads to corrosion issues due to chloride residues, and tin nitrate solutions are metastable, causing premature precipitation and instability, which affects catalyst performance and selectivity in amine production processes.

Innovation Solution

A stable tin-containing catalyst is produced by using a solution with tin nitrate and a complexing agent, such as citric acid, which remains clear and stable at room temperature, ensuring tin is evenly distributed and bound to the catalyst support, preventing corrosion and enhancing selectivity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If tin chloride is used in catalyst production, then tin can be introduced into the catalyst, but chloride residues cause corrosion issues

Engineering Contradiction:
Improvetin contentVSAvoidcorrosion
Core Design Contradiction:
Quantity of substanceVSObject-affected harmful factors

Solution Approach 1:

The harmful chloride component is extracted and removed from the tin source compound. Instead of using tin chloride, the invention uses tin nitrate which decomposes to form tin oxide without leaving corrosive chloride residues, thereby eliminating the corrosion problem while maintaining tin introduction capability.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The chemical composition parameter of the tin source is changed from chloride to nitrate. This parameter change fundamentally alters the decomposition products: tin chloride produces corrosive HCl, while tin nitrate produces non-corrosive HNO3 and tin oxide, thus resolving the corrosion issue.

Inventive Principle:
Principle #35Parameter changes

2Device complexity

If tin nitrate solution is used without complexing agent, then the solution is simpler, but it is metastable and tin precipitates quickly

Engineering Contradiction:
Improvesolution compositionVSAvoidsolution stability
Core Design Contradiction:
Device complexityVSStability of the object's composition

Solution Approach 1:

A complexing agent acts as an intermediary substance that mediates between the tin nitrate and the solution environment. The complexing agent forms stable complexes with tin ions, preventing premature precipitation while maintaining solution stability at room temperature, thus enabling simple yet stable catalyst preparation.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Stability of the object's composition

If tin nitrate solution is cooled to very low temperatures, then solution stability increases, but the process becomes technically complex

Engineering Contradiction:
Improvesolution stabilityVSAvoidcooling system
Core Design Contradiction:
Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The complexing agent serves as a chemical intermediary that provides stability without requiring physical cooling. By forming stable complexes, the agent allows the solution to remain stable at convenient room temperatures, eliminating the need for complex cooling infrastructure and making the process industrially viable.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The chemical parameter of the solution is changed by adding complexing agents, which fundamentally alters the stability characteristics. This chemical modification replaces the need for low-temperature physical conditions, allowing stable operation at higher, more practical temperatures.

Inventive Principle:
Principle #35Parameter changes

4Duration of action of stationary object

If stable tin nitrate solution with complexing agent is used, then long-term storage at room temperature is possible, but the solution requires additional components

Engineering Contradiction:
Improvestorage timeVSAvoidsolution composition
Core Design Contradiction:
Duration of action of stationary objectVSDevice complexity

Solution Approach 1:

The complexing agent acts as a stabilizing intermediary that enables long-term storage. Common agents like citric acid or EDTA form very stable complexes with tin, extending shelf life from hours to months or years, and this additional component is a small price for achieving industrial-scale storage stability.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 stable tin nitrate solution allows for long-term storage and use at room temperature, reducing corrosion risks and improving catalyst selectivity, leading to cost advantages in large-scale processes by maintaining catalyst performance and preventing pitting corrosion.

Implementation Method 1

a solution (L) containing tin nitrate and at least one complexing agent is applied to the support, the solution (L) containing no solids or a solids content of a maximum of 0.5% by weight

Methodology Applied
Scientific EffectComplex formation: Chemical Bonding

Data Source

PatentEP2780109B1Process for producing sn-containing catalysts
Publication Date: 2016.04.13 BASF SE

AI summary

The present invention relates to a process for producing a supported tin-containing catalyst, characterized in that a solution (L) containing tin nitrate and at least one complexing agent is applied to the support, where the solution (L) does not contain any solid or has a solids content of not more than 0.5% by weight, based on the total amount of dissolved components.