Hexafluorophosphate Route to High-Purity PF5 Without HF Feedstock
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Solution Overview
Problem
The existing methods for preparing hexafluorophosphate salts and phosphorus pentafluoride in lithium-ion batteries are hazardous due to the use of toxic and corrosive hydrogen fluoride, requiring expensive and difficult-to-handle raw materials, and result in low yields with significant impurities and equipment corrosion.
Innovation Solution
A method using phosphorus pentoxide and sulfur trioxide as raw materials to produce hexafluorophosphate salts, avoiding the need for phosphorus pentafluoride and hydrogen fluoride, which reduces safety risks and production costs, and involves a series of controlled reactions and purifications to achieve high-purity phosphorus pentafluoride.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If phosphorus pentafluoride and hydrogen fluoride are used as raw materials to prepare hexafluorophosphate salts, then the preparation method follows conventional processes, but the production safety deteriorates due to toxicity and corrosiveness
Solution Approach 1:
The patent extracts and removes the harmful substances (phosphorus pentafluoride and hydrogen fluoride) from the raw material system, replacing them with safe alternatives (phosphorus pentoxide and sulfur trioxide). This eliminates the toxicity and corrosiveness while maintaining the ability to produce hexafluorophosphate salts through a modified chemical pathway.
Solution Approach 2:
The patent employs readily available, inexpensive raw materials (phosphorus pentoxide and sulfur trioxide) that can be easily handled and disposed of, replacing the expensive and hazardous phosphorus pentafluoride and hydrogen fluoride. This substitution improves both safety and economic aspects of the preparation process.
2Ease of manufacture
If phosphorus pentafluoride is used as raw material, then hexafluorophosphate salts can be prepared, but the equipment complexity increases due to anti-corrosion requirements
Solution Approach 1:
The patent removes the corrosive phosphorus pentafluoride from the reaction system and replaces it with non-corrosive phosphorus pentoxide and sulfur trioxide. This elimination of corrosive substances simplifies equipment requirements, removing the need for complex anti-corrosion measures while maintaining product preparation capability.
3Productivity
If existing preparation methods are used, then hexafluorophosphate salts can be produced, but the manufacturing precision deteriorates due to impurities
Solution Approach 1:
The patent converts the previously harmful side reactions and impurity formations into beneficial outcomes. By using phosphorus pentoxide and sulfur trioxide as raw materials, the reaction pathway is optimized to minimize impurity generation, and any by-products formed are easier to separate and remove, thereby improving product purity while maintaining production output.
Solution Approach 2:
The patent changes the chemical parameters of the raw materials from phosphorus pentafluoride/hydrogen fluoride to phosphorus pentoxide/sulfur trioxide. This parameter change fundamentally alters the reaction characteristics, leading to fewer impurities and higher product purity while maintaining acceptable production rates.
4Ease of manufacture
If phosphorus pentafluoride and hydrogen fluoride are used, then conventional preparation can proceed, but the loss of substance increases due to decomposition and side reactions
Solution Approach 1:
The patent substitutes stable, non-volatile phosphorus pentoxide and sulfur trioxide for the volatile and decomposition-prone phosphorus pentafluoride and hydrogen fluoride. This substitution reduces material loss through decomposition and side reactions, improving overall material utilization efficiency while maintaining conventional preparation capabilities.
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 approach results in a safer, more cost-effective, and scalable production of high-purity hexafluorophosphate salts and phosphorus pentafluoride with reduced impurities and improved reaction conditions, facilitating industrial large-scale production.
Implementation Method 1
mixing a phosphoric acid solution of phosphorus pentoxide, sulfur trioxide and fluoride under an inert gas atmosphere, and performing reaction to obtain a hexafluorophosphate salt precursor
Implementation Method 2
subjecting the hexafluorophosphate salt precursor obtained in step (1) to evaporation and concentration
Implementation Method 3
evaporation and concentration, dissolution, filtration and drying
Implementation Method 4
subjecting the crude phosphorus pentafluoride gas obtained in step (a) to condensation, pressurizing liquefaction and adsorption impurity removal
Implementation Method 5
condensation, pressurizing liquefaction and adsorption impurity removal in sequence to obtain the phosphorus pentafluoride
Data Source
AI summary
Disclosed are a hexafluorophosphate, phosphorus pentafluoride, a preparation method therefor and an application thereof. The preparation method for the hexafluorophosphate comprises the following steps: mixing a phosphoric acid solution of phosphorus pentoxide, sulfur trioxide and a fluoride in an inert gas atmosphere, sequentially performing evaporation concentration, dissolution, filtration and drying after the reaction, and obtaining the hexafluorophosphate. The method for preparing phosphorus pentafluoride from the hexafluorophosphate obtained by the preparation method provided by the present application comprises the following steps: mixing the hexafluorophosphate and a catalyst solution, carrying out catalytic reaction, and sequentially performing condensation, pressurized liquefaction and adsorption-based impurity removal, and obtaining phosphorus pentafluoride. The present application does not use phosphorus pentafluoride as a raw material to prepare the hexafluorophosphate, and does not use hydrogen fluoride as a raw material to produce phosphorus pentafluoride, thereby reducing risk related to production safety. Meanwhile, widely available chemical reagents of phosphorus pentoxide and sulfur trioxide are used as raw materials, thereby reducing the raw material cost and facilitating large-scale industrial production.