BNA Purification via Sodium Salt Precipitation
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Solution Overview
Problem
Current methods for producing 6-bromo-2-naphthalenecarboxylic acid (BNA) result in low purity and require high-pressure conditions, leading to increased costs and the need for advanced refining treatments.
Innovation Solution
Reacting crude BNA with sodium hydroxide to form a sodium salt, followed by recrystallization and subsequent acidification to produce high-purity BNA, utilizing the low solubility of the sodium salt in water to effectively remove impurities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If oxidation reaction is executed under high temperature and high pressure conditions, then productivity is improved, but purity of BNA product deteriorates
Solution Approach 1:
The invention changes the physical-chemical parameters of the system by converting BNA from its acid form to sodium salt form through reaction with sodium hydroxide. This parameter change exploits the differential solubility characteristics: the sodium salt exhibits low solubility in water at ordinary temperatures, enabling selective precipitation and separation from impurities that remain dissolved, thereby achieving high purity without requiring high-pressure oxidation conditions
Solution Approach 2:
The invention utilizes phase transition of the sodium salt of BNA from dissolved state to solid precipitate state by controlling temperature and solubility characteristics. By maintaining ordinary temperature conditions and exploiting the low solubility of sodium BNA in water, the product transitions to a solid crystalline phase that can be easily separated from the liquid phase containing impurities, achieving purification without high-pressure conditions
2Productivity
If oxidation reaction is executed under high pressure conditions, then productivity is improved, but device complexity and cost increase due to special pressure facilities
Solution Approach 1:
The invention fundamentally changes the pressure parameter from high-pressure conditions to ordinary temperature and pressure conditions by using sodium hydroxide treatment followed by selective precipitation. This parameter change eliminates the need for pressure-resistant equipment, special materials, and complex pressure control systems, thereby reducing device complexity and capital investment while maintaining productivity through efficient solid-liquid separation
Solution Approach 2:
The invention replaces expensive, complex high-pressure facilities with simple, inexpensive ordinary equipment suitable for atmospheric pressure operations. The use of common chemicals like sodium hydroxide and water, along with basic filtration and crystallization equipment, substitutes for costly pressure vessels and special material constructions, making the process economically viable
3Manufacturing precision
If advanced refining treatment is performed to improve purity, then purity of BNA product is improved, but loss of time and additional processing steps increase
Solution Approach 1:
The invention performs preliminary action by converting BNA to its sodium salt form before the purification step. This preliminary conversion creates a compound with specific solubility characteristics that enable direct precipitation and separation in a single operation. By preparing the substance in advance in the appropriate chemical form, the invention achieves high purity in one step rather than requiring multiple sequential refining operations
Solution Approach 2:
The invention extracts the BNA product from the reaction mixture in the form of sodium salt through selective precipitation. By adding sodium hydroxide, the BNA is converted to sodium BNA which precipitates out of solution, effectively extracting it from the liquid phase containing impurities. This single extraction step achieves high purity without requiring multiple refinement stages
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 achieves a refined BNA product with a purity of up to 99.9% and a high yield, reducing the need for costly high-pressure facilities and advanced refining processes.
Implementation Method 1
If, however, BNA is caused to react with sodium hydroxide in water, then the produced sodium salt of BNA (referred also as 'NaBNA ', hereinafter) has a low solubility in water as the solvent. Accordingly, NaBNA remains in a solid state in the reaction liquid
Implementation Method 2
performing recrystallization treatment for the obtained precipitate
Implementation Method 3
causing the obtained crystal to react with acid in water to precipitate 6-bromo-2-naphthalenecarboxylic acid (BNA)
Data Source
AI summary
The present invention provides a method, as a means for industrially producing a refined 6-bromo-2-naphthalenecarboxylic acid product from a crude 6-bromo-2-naphthalenecarboxylic acid product, comprising: causing the above crude product to react with sodium hydroxide in water to precipitate a sodium salt of 6-bromo-2-naphthalenecarboxylic acid; performing recrystallization treatment for the obtained precipitate; causing the obtained crystal to react with acid in water to precipitate 6-bromo-2-naphthalenecarboxylic acid; and recovering the obtained precipitate.