Lanthanide Carboxylate Purification via pH Control and Molecular Sieves
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Solution Overview
Problem
The presence of variable and non-reproducible amounts of carboxylic acid and water in lanthanide carboxylate solutions complicates the activation phase before polymerization, leading to increased costs due to higher aluminum consumption and altered polymerization kinetics and molecular weight distribution.
Innovation Solution
A method involving treating hydrocarbon solutions of lanthanide carboxylates with an aqueous base to achieve a specific pH range and/or using molecular sieves to remove excess carboxylic acid and water, resulting in solutions with minimal protogenic substances, thereby optimizing aluminum consumption and maintaining consistent polybutadiene characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional synthesis methods are used to produce lanthanide carboxylate solutions, then the polymerization process can proceed, but the presence of variable amounts of carboxylic acid and water leads to increased aluminum consumption and altered polymerization kinetics
Solution Approach 1:
The patent applies preliminary action by performing purification of the lanthanide carboxylate solution before the polymerization process. The method removes carboxylic acid and water impurities through treatment with base and/or molecular sieves, ensuring the solution is purified in advance. This preliminary purification prevents the harmful effects of impurities during polymerization, including excessive aluminum consumption and altered kinetics, without requiring complex modifications to the polymerization process itself.
2Ease of manufacture
If conventional synthesis methods are used, then lanthanide carboxylate solutions can be obtained, but the amounts of carboxylic acid and water are variable and non-reproducible
Solution Approach 1:
The patent applies parameter changes by systematically controlling the pH of the aqueous phase during purification (maintaining pH between 9.0 and 12.2) and by controlling the contact time with molecular sieves (at least 1 hour). These parameter controls transform the variable and non-reproducible purification process into a consistent manufacturing method that reliably produces solutions with carboxylic acid content below detection limits and water content below 0.005% by weight, while maintaining ease of manufacture through simple sequential steps.
3Manufacturing precision
If high vacuum solvent evaporation is used to remove impurities, then purity can be increased, but the process becomes more complex and time-consuming
Solution Approach 1:
The patent applies this principle by using disposable molecular sieves (3Å, 4Å, 5Å, or 13X) that are added directly to the solution, perform their purification function, and are then removed as solid waste. This disposable approach eliminates the need for complex high vacuum solvent evaporation equipment while achieving superior purity results. The molecular sieves act as single-use purification agents that simplify the overall process by converting a complex equipment-intensive purification into a simple addition-removal operation.
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 effectively purifies lanthanide carboxylate solutions to achieve high purity, ensuring stability and consistency in polybutadiene production without the need for high vacuum solvent evaporation, and allows for non-destructive analytical measurement of residual impurities using IR spectroscopy.
Implementation Method 1
treating the hydrocarbon solution containing lanthanide carboxylate with a solid selected from Na2SO4, MgSO4, Mg(ClO4)2, molecular sieves 3 Å, molecular sieves 4 Å, molecular sieves 5 Å and molecular sieves 13 X
Implementation Method 2
treating the hydrocarbon solution deriving from the synthesis of lanthanide carboxylate, containing said carboxylate and impurities of the corresponding carboxylic acid and/or water, with an aqueous solution of a base in order to obtain a suitable pH of the aqueous phase
Implementation Method 3
analytical methods are also described, which allow the purity of the lanthanide carboxylates to be non-destructively measured
Data Source
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AI summary
A process is described for the purification of lanthanide carboxylates which comprises a step in which the hydrocarbon solution deriving from the synthesis of lanthanide carboxylate, containing said carboxylate and impurities of the corresponding carboxylic acid and/or water, is treated with an aqueous solution of a base in order to obtain a pH of the aqueous phase ranging from 9.0 to 12.2 and/or a step in which the hydrocarbon solution containing lanthanide carboxylate is treated with a solid selected from Na2SO4, MgSO4, Mg(ClO4)2, molecular sieves 3 Å, molecular sieves 4 Å, molecular sieves 5 Å and molecular sieves 13 X. Analytical methods are also described, which allow the purity of the lanthanide carboxylates to be non-destructively measured.