Phosphorus Oxychloride Production From Phosphates Without Carbon Tetrachloride
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Solution Overview
Problem
Existing methods for producing phosphorus oxychloride are energy-intensive, involve hazardous materials, generate large waste, and require complex filtration steps, while direct conversion from phosphates to phosphorus-chlorine compounds is hindered by the use of ozone-damaging carbon tetrachloride.
Innovation Solution
A process that converts phosphorus-oxygen compounds, such as calcium phosphates, into phosphoryl chloride by reacting them with tetrachloroethene or chloroform at high temperatures (500 to 1000°C) in the presence of an inert gas, allowing the phosphoryl chloride to be collected in an exhaust gas stream.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the conventional process of extracting elemental phosphorus from phosphate rock via electric arc furnace is used, then phosphorus-chlorine compounds can be produced, but very high electricity consumption and high temperatures are required
Solution Approach 1:
The invention extracts and utilizes phosphorus directly from phosphate rock in the form of phosphorus oxychloride vapor during the roasting process, eliminating the need for the energy-intensive electric arc furnace step that converts phosphate to elemental phosphorus. The phosphorus is taken out in a useful form (POCl3) directly from the waste material.
Solution Approach 2:
The invention introduces carbon tetrachloride as an intermediary substance that facilitates the conversion of phosphorus from phosphate rock to phosphorus oxychloride at lower temperatures. This intermediary enables the reaction to proceed without requiring the extreme conditions of the electric arc furnace.
2Productivity
If phosphate rock is processed with sulfuric acid to obtain water-soluble phosphoric acid, then phosphorus can be utilized technically, but very large quantities of acid are required and large quantities of waste are generated
Solution Approach 1:
The invention converts the previously useless waste material (phosphate rock slurry from fertilizer production) into a valuable product (phosphorus oxychloride). What was previously discarded as waste is now the feedstock for producing technical phosphorus compounds, turning a harmful environmental burden into an economic asset.
Solution Approach 2:
The invention changes the chemical parameters of the processing system by using carbon tetrachloride and chlorine gas in a high-temperature roasting process instead of sulfuric acid dissolution. This parameter change transforms the reaction pathway from acid dissolution to thermal decomposition and chlorination, eliminating waste stream generation.
3Ease of manufacture
If carbon tetrachloride is used for direct recovery of phosphorus-chlorine compounds from phosphates, then the process can be simplified, but the compound damages the ozone layer making the reaction technically impossible
Solution Approach 1:
The invention replaces the ozone-damaging carbon tetrachloride with tetrachloroethene, which serves the same chemical function as a chlorinating agent but without the harmful ozone-depleting properties. This substitution maintains the simplicity of the direct conversion process while eliminating environmental harm.
Solution Approach 2:
The invention changes the chemical identity of the chlorinating agent from carbon tetrachloride to tetrachloroethene, altering the molecular structure to remove the harmful ozone-depleting characteristics while preserving the functional ability to convert phosphates to phosphorus oxychloride.
4Productivity
If phosphorus oxychloride is produced from PCl3 via oxidation, then POCl3 can be obtained, but an additional production step is required increasing process complexity
Solution Approach 1:
The invention merges the chlorination and oxidation steps into a single integrated roasting process. Phosphate rock is directly converted to phosphorus oxychloride in one operation rather than requiring separate steps to first produce PCl3 and then oxidize it to POCl3. This consolidation eliminates intermediate processing equipment and simplifies the overall process flow.
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 phosphoryl chloride efficiently with reduced energy consumption, minimal waste, and avoids the use of ozone-depleting substances, offering a more environmentally friendly and cost-effective production process.
Implementation Method 1
reacts a phosphorus-oxygen compound-containing material from the group of calcium phosphates in the presence of tetrachloroethene at a temperature of 500 to 1000°C
Implementation Method 2
converts phosphorus-oxygen compounds, such as calcium phosphates, into phosphoryl chloride by reacting them with tetrachloroethene or chloroform at high temperatures
Implementation Method 3
discharges and isolates the phosphorus oxychloride formed in the exhaust gas stream
Data Source
AI summary
The invention relates to a process for the production of phosphorus-chlorine compounds characterized in that i. a phosphorus-oxygen compound-containing material is reacted in the presence of tetrachloroethene at a temperature of 500 to 1000°C and ii. the phosphorus-chlorine compounds formed, in particular phosphorus oxychloride, are removed and isolated from the exhaust gas stream.