Zinc Dithiolate Preparation Without Ethylenediamine Residues
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Solution Overview
Problem
Existing methods for producing zinc dithiolate compounds face challenges such as slow filtration, difficulty in isolation, use of hazardous solvents, poor solubility, and the presence of toxic ethylenediamine, which complicates catalyst production on a production scale and affects catalyst properties.
Innovation Solution
A method involving the reaction of zinc carboxylates with dithiols in organic solvents at controlled temperatures, allowing for the in situ formation of zinc-dithiolato complexes without ethylenediamine, simplifying the process and improving solubility and purity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If zinc dithiolate compounds are prepared using conventional methods with ethylenediamine, then the catalyst shows stereo-retentive activity, but the product contains toxic ethylenediamine residues that detrimentally affect catalyst properties and require complex isolation procedures
Solution Approach 1:
The invention removes the harmful ethylenediamine component from the reaction system by using alternative bases such as triethylamine or diisopropylethylamine. This extraction of the harmful substance eliminates toxic residues in the final catalyst product while maintaining the necessary basic conditions for zinc dithiolate formation, thereby preserving catalyst activity without the detrimental effects of ethylenediamine
Solution Approach 2:
The invention employs volatile amine bases like triethylamine that can be easily removed from the reaction mixture. These bases serve their function during the reaction and then can be completely eliminated through simple evaporation or filtration, leaving no harmful residues in the final catalyst product, thus solving both the activity and purity requirements
2Manufacturing precision
If zinc dithiolate compounds are isolated using hot chloroform filtration, then impurities are removed, but the filtration process is slow, difficult, and poses safety hazards
Solution Approach 1:
The invention changes the physical state parameters of the reaction system by conducting the reaction in solvents where the zinc dithiolate product has low solubility at reaction temperature but high solubility in the filtrate. This parameter change allows the product to precipitate in a filterable form while impurities remain dissolved, enabling fast and safe filtration without requiring hot chloroform and achieving both high purity and high productivity
3Quantity of substance
If zinc dithiolate compounds are prepared with conventional reagents, then the reaction proceeds, but the product exhibits bad solubility in organic solvents making characterization and analysis difficult
Solution Approach 1:
The invention introduces an intermediary step where the zinc dithiolate is prepared as a soluble complex or salt that can be easily characterized and analyzed in organic solvents. This intermediary form maintains the core zinc-dithiolate structure and catalytic activity while possessing improved solubility properties that facilitate NMR, IR, and other spectroscopic analyses, and the compound can subsequently be converted to the active catalytic form
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 method enables high-yield, high-purity production of zinc dithiolate compounds with low nitrogen content, facilitating the production of stereo-retentive catalysts suitable for industrial applications.
Implementation Method 1
The invention relates to a method for making a zinc dithiolate compound by reacting a compound of formula 2 or formula 2a with a zinc carboxylate in an organic solvent
Data Source
Figure 1
AI summary
The Invention relates to a method for the preparation of zinc dithiolate compounds by reacting aromatic 1,2-dithiols with zinc carboxylates in an organic solvents.