Cyclohexanol Purification via Distillation to Remove High-Boiling Impurities
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Solution Overview
Problem
The production of cyclohexanol through hydration of cyclohexene results in by-products that cause coloration and impurities in adipic acid, leading to lower quality and yield issues due to the inability to separate high-boiling point components effectively, which affects the purification process and industrial applicability.
Innovation Solution
A method is developed to purify cyclohexanol by controlling the concentrations of methylcyclopentanol and cyclohexylcyclohexene isomers within specific ranges (10-1000 ppm and 15-500 ppm, respectively) through a hydration reaction, separation, and distillation steps, ensuring the removal of impurities and achieving high-quality adipic acid production.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If cyclohexanol is purified by distillation to remove by-products, then the purity of cyclohexanol is improved, but the high-boiling point components cannot be separated and remain in the purified product causing coloration
Solution Approach 1:
The invention extracts and removes high-boiling point components (such as dicyclohexyl ether and cyclohexylcyclohexene) from cyclohexanol through a specific distillation process. By controlling the distillation conditions and using a fractionating column, these harmful by-products are separated and removed from the cyclohexanol before oxidation, preventing the coloration problem in the final adipic acid product while maintaining high purity.
2Ease of manufacture
If cyclohexanol is produced by hydration of cyclohexene, then the production cost is reduced, but by-products are generated that cause coloration and impurities in adipic acid
Solution Approach 1:
The invention performs preliminary removal of high-boiling point by-products from cyclohexanol before the oxidation step. By conducting a pre-distillation process to eliminate dicyclohexyl ether and cyclohexylcyclohexene before oxidation, the harmful effects of these by-products on adipic acid quality are prevented, allowing the use of the cost-effective cyclohexene hydration route without compromising product quality.
3Productivity
If high-boiling point components are present in cyclohexanol, then the yield of cyclohexanol is maintained, but the purification process becomes problematic and industrial applicability is reduced
Solution Approach 1:
The invention changes the operational parameters of the distillation process to effectively separate high-boiling point components. By optimizing the distillation temperature, pressure, and column configuration, the process achieves efficient separation of dicyclohexyl ether and cyclohexylcyclohexene from cyclohexanol. This parameter optimization maintains high cyclohexanol yield while making the purification process industrially viable and operationally simple.
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 suppresses the production of by-products, resulting in high-quality adipic acid with improved melting color number and yield, addressing the issues of coloration and impurities, and enhancing the industrial viability of cyclohexanol as a raw material.
Implementation Method 1
a method for bringing a crystalline metallosilicate used as a solid catalyst into contact with cyclohexene in a liquid phase has been known as the method for producing cyclohexanol by hydration of cyclohexene
Implementation Method 2
separated the resultant into a high-boiling point fraction and a low-boiling point fraction by distillation to obtain a purified cyclohexanol
Implementation Method 3
A method in which cyclohexanone and/or cyclohexanol is oxidized by nitric acid to synthesize adipic acid
Data Source
AI summary
A purified cyclohexanol of the present invention has a methylcyclopentanol concentration of 10 to 1000 ppm by weight and a cyclohexylcyclohexene isomer concentration of 15 to 500 ppm by weight. A method for producing cyclohexanol of the present invention comprises: Step 1 of producing a solution (I) containing cyclohexanol, methylcyclopentanol, and water by a hydration reaction of cyclohexene; Step 2 of separating the solution (I) into a water phase and an oil phase; Step 3 of obtaining a partially purified cyclohexanol containing methylcyclopentanol from the oil phase; and Step 4 of separating and removing methylcyclopentanol in the partially purified cyclohexanol so as to obtain a purified cyclohexanol having a methylcyclopentanol concentration of 10 to 1000 ppm by weight and a cyclohexylcyclohexene isomer concentration of 15 to 500 ppm by weight.