Scandium Sorbent via Acylation-Phosphorylation
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Solution Overview
Problem
Existing methods for extracting scandium from acidic solutions suffer from low selectivity, especially in the presence of iron (III), leading to increased costs and a more expensive scandium end product, and involve hazardous and inefficient processes such as acylation with carbon disulfide and prolonged reaction times.
Innovation Solution
A method involving the acylation of a macroporous styrene-divinylbenzene copolymer with acetyl chloride at 52°C for 6 hours, followed by phosphorylation at room temperature for 24 hours with phosphorus trichloride, and subsequent treatment with glacial acetic acid, enhances the selectivity of the sorbent for scandium by forming sterically congested α-hydroxyphosphonic acid complexes, reducing the availability of sorption sites for larger complexes and increasing electron density on the phosphoryl oxygen.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If carbon disulfide is used as solvent for acylation, then the reaction can proceed, but fire and explosion hazard increases
Solution Approach 1:
The patent replaces the hazardous carbon disulfide solvent with dichloroethane, which has favorable boiling point and solvation properties without the fire and explosion risks. This substitution maintains reaction effectiveness while eliminating the harmful factors associated with the original solvent.
2Manufacturing precision
If acylation is carried out for prolonged duration, then reaction completeness improves, but production effectiveness decreases
Solution Approach 1:
The patent optimizes the acylation reaction parameters by conducting the reaction at 52°C (boiling point of dichloroethane) for 6 hours, which achieves complete reaction while significantly reducing the time compared to the prior art's 80 hours. The temperature and time parameters are carefully selected to balance reaction completeness with production efficiency.
3Ease of manufacture
If conventional acylation-phosphorylation method is used, then sorbent is produced, but selectivity for scandium is insufficient
Solution Approach 1:
The patent introduces a pre-swelling step where the copolymer is swollen in the acetyl chloride-dichloroethane mixture for 0.5 hours before acylation. This pre-swelling creates a specific porous structure and facilitates controlled reagent penetration, leading to more uniform functional group distribution and enhanced selectivity for scandium ions.
Solution Approach 2:
The patent uses a macroporous styrene-divinylbenzene copolymer as the base material, which provides a robust porous structure. This composite approach combines the mechanical strength of the copolymer matrix with the selective binding properties of the phosphoryl functional groups, achieving both ease of manufacture and high selectivity.
4Reliability
If oxidation with nitric acid is performed, then sorbent activation improves, but process complexity and cost increase
Solution Approach 1:
The patent eliminates the oxidation step with nitric acid from the process. The phosphorylation reaction alone is sufficient to create the active sorbent material, removing an unnecessary step that added complexity and cost without providing additional benefit to sorbent performance.
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 significantly increases the selectivity of the sorbent for scandium, demonstrated by higher distribution coefficients and selectivity ratios compared to iron (III), while simplifying the process by avoiding hazardous reagents and reducing reaction times, resulting in a more effective and efficient scandium extraction process.
Implementation Method 1
said styrene-divinylbenzene copolymer is pre-swelled in a mixture of said acetyl chloride and dichloroethane for 0.5 hours
Implementation Method 2
the step of phosphorylation of the acylation product with phosphorus trichloride
Implementation Method 3
forming sterically congested α-hydroxyphosphonic acid complexes
Implementation Method 4
increasing electron density on the phosphoryl oxygen
Data Source
AI summary
The invention relates to production of sorbents. The proposed method of production involves acylation of a macroporous styrene-divinylbenzene copolymer in the presence of the Friedel-Crafts catalyst - aluminum chloride. The acylation reaction is carried out using acetyl chloride in a dichloroethane solvent at boiling the solution. This is followed by phosphorylation of the obtained acylated copolymer with phosphorus trichloride at room temperature; the product is hydrolyzed with water, washed and dried. The technical result consists in production of a complexing adsorbent highly selective for scandium and simplification of the production process.