Crystallization of 4-hydroxyacetophenone Using Ethanol and Ethyl Acetate
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Solution Overview
Problem
Current methods for purifying crude 4-hydroxyacetophenone, such as recrystallization from water and column chromatography, are inefficient and costly, leading to low production rates and high residual phenol content, making them unsuitable for industrial-scale production.
Innovation Solution
A method involving the use of a combination of ethanol and ethyl acetate to purify crude 4-hydroxyacetophenone, which includes steps such as mixing with the solvents, optional heating and cooling to induce crystallization, and filtration to collect the crystallized product.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If recrystallization from water is used to purify crude 4-hydroxyacetophenone, then the product purity can be improved, but the solvent consumption increases and production efficiency decreases
Solution Approach 1:
The patent changes the solvent parameter from water to a mixture of ethanol and ethyl acetate. This parameter change enables better solubility of 4-hydroxyacetophenone at elevated temperatures, allowing for more efficient crystallization with lower solvent-to-material ratios and higher production efficiency while maintaining high product purity
Solution Approach 2:
The patent uses a composite solvent system consisting of ethanol and ethyl acetate instead of a single solvent. This composite approach provides optimal solubility characteristics for 4-hydroxyacetophenone, enabling efficient purification and crystallization processes that improve both productivity and product quality
2Manufacturing precision
If recrystallization from water is used, then purification can be achieved, but the product form changes from crystalline to powder with poor flowability
Solution Approach 1:
The patent changes the crystallization parameters by using ethanol/ethyl acetate as the solvent system and controlling cooling rates. This results in the formation of well-defined crystalline structures with improved flowability and physical properties, rather than amorphous powder, while maintaining high purity
3Manufacturing precision
If column chromatography is used to purify crude 4-hydroxyacetophenone, then high purity can be achieved, but the process complexity and cost increase
Solution Approach 1:
The patent extracts and removes impurities through simple filtration during the crystallization process. By forming pure crystals that can be separated from impurities through filtration, the method avoids the need for complex column chromatography equipment and procedures, significantly reducing process complexity and cost while achieving high purity
Solution Approach 2:
The patent uses simple, inexpensive filtration equipment and common laboratory glassware instead of expensive column chromatography systems. This approach employs readily available materials and simple operations to achieve the same purification effect, making the process more economical and suitable for industrial scale
4Manufacturing precision
If water is used for recrystallization, then purification can be performed, but the solvent volume required becomes very large
Solution Approach 1:
The patent changes the solvent parameters by using ethanol and ethyl acetate, which have superior solubility characteristics for 4-hydroxyacetophenone. This allows for much lower solvent-to-material ratios compared to water, significantly reducing the quantity of solvent required while maintaining effective purification and high product purity
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 high purity (up to 99.99%) of crystalline 4-hydroxyacetophenone with improved solubility and flowability, reducing residual phenol content and solvent consumption, making it suitable for industrial-scale production.
Implementation Method 1
mixing the crude 4-hydroxyacetophenone of step (a) with ethanol and ethyl acetate
Implementation Method 2
optionally, heating the mixture obtained in step (b) to (fully) dissolve the 4-hydroxyacetophenone
Implementation Method 3
cooling of the mixture obtained in step (b) or step (c), if present, or further cooling of the mixture obtained in step (e), if step (d) is not present, or step (f), if present, to a temperature below the crystallization temperature of 4-hydroxyacetophenone to induce crystallization of 4-hydroxyacetophenone
Implementation Method 4
collecting the crystallized 4-hydroxyacetophenone obtained in step (g)
Data Source
AI summary
The present invention primarily relates to a method of purifying crude 4-hydroxyacetophenone with a combination of ethanol and ethyl acetate as described herein. The present invention furthermore relates to a product comprising or consisting of crystallized 4-hydroxyacetophenone and ethanol and ethyl acetate, the product being obtained or obtainable by a method as defined herein. Finally, the present invention relates to the use of a combination of ethanol and ethyl acetate to (re) crystallize 4-hydroxyacetophenone.