Ammonium Tetrathiomolybdate Crystallization via Ammonium Sulfide
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Solution Overview
Problem
The commercial production of ammonium tetrathiomolybdate (ATTM) is limited by impurities, batch size, and the use of toxic hydrogen sulfide gas, which poses health, safety, and environmental concerns, and affects the quality and scalability of bis-choline tetrathiomolybdate (BC-TTM) production.
Innovation Solution
A process involving the reaction of a molybdenum compound with water and ammonia, followed by the addition of ammonium sulfide at a controlled temperature and pH, to produce crystalline ATTM with high purity, minimizing hydrogen sulfide use and incorporating a crystallization step to achieve pharmaceutical-grade purity, and subsequently using this ATTM to manufacture BC-TTM with low impurity levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If commercially available ATTM is used, then production can proceed, but the product contains relatively large amounts of impurities and shows batch-to-batch variability
Solution Approach 1:
The patent changes the chemical reaction parameters by using ammonium sulfide instead of hydrogen sulfide, controlling the S:Mo molar ratio between 4.5:1 and 6.5:1, and maintaining reaction temperature between 35°C and 55°C. These parameter changes result in ATTM with ≥96% purity and consistent batch-to-batch quality
Solution Approach 2:
The patent introduces an intermediary crystallization step where the reaction mixture is cooled to 10°C-30°C to precipitate crystalline ATTM. This intermediary separation step removes impurities from the solution phase, achieving pharmaceutical-grade purity and consistent batch quality
2Productivity
If small batch sizes are used, then lab-scale safety is maintained, but production scalability and supply ability are limited
Solution Approach 1:
The patent changes the reaction parameters to use ammonium sulfide with S:Mo ratio of 4.5:1 to 6.5:1 and temperature control at 35°C-55°C, which enables safe large-scale production. The process has been successfully scaled to multi-kilogram batches while maintaining consistent purity ≥96% and reducing the need for multiple batches
3Ease of manufacture
If hydrogen sulfide is used, then the reaction can proceed, but toxic gas handling requirements limit production scale and create safety concerns
Solution Approach 1:
The patent converts the harmful hydrogen sulfide gas route into a beneficial liquid-phase reaction using ammonium sulfide. This substitution eliminates toxic gas generation while maintaining reaction effectiveness, enabling safe large-scale production without specialized gas handling equipment
Solution Approach 2:
The patent uses ammonium sulfide as an intermediary reagent that delivers sulfur to the reaction without generating toxic hydrogen sulfide gas. The ammonium sulfide solution provides controlled sulfur delivery at S:Mo ratios of 4.5:1 to 6.5:1, eliminating the need for hazardous gas handling while achieving the same chemical transformation
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 achieves ATTM with yields of at least 75% and purities of 96% or higher, significantly reducing impurities and the use of toxic hydrogen sulfide, enabling large-scale, safe, and compliant production of ATTM and BC-TTM with improved regulatory and safety standards.
Implementation Method 1
providing ammonium sulfide to the molybdenum compound solution in an amount corresponding to a S:Mo molar ratio in a range of 4.5:1 to 6.5:1 over a period of time sufficient to obtain a reaction mixture
Implementation Method 2
removing liquid from the slurry to obtain crystalline ATTM
Data Source
AI summary
This disclosure relates to crystalline ammonium tetrathiomolybdate having pharmaceutical grade purity and processes for manufacturing crystalline ammonium tetrathiomolybdate. This disclosure also relates to processes for manufacturing bis-choline tetrathiomolybdate having pharmaceutical grade purity.