Cyclohexanone Purification via Hydrogenation of Enone Impurities
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Solution Overview
Problem
The existing processes for producing cyclohexanone from cyclohexylbenzene oxidation and hydroperoxide cleavage face challenges due to the presence of 2-cyclohexenone and 3-cyclohexenone impurities, which cause issues in downstream applications such as caprolactam production, and are inefficient in maintaining catalyst activity and selectivity.
Innovation Solution
A process involving hydrogenation of a feed mixture containing cyclohexanone and 3-cyclohexenone, using a hydrogenation catalyst, to convert 2-cyclohexenone and 3-cyclohexenone into cyclohexanone, thereby reducing their concentrations to low levels, is implemented, including steps of distillation and hydrogenation reactor configurations to achieve high conversion rates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If cyclohexylbenzene oxidation and hydroperoxide cleavage are used to produce cyclohexanone, then cyclohexanone can be produced efficiently, but 2-cyclohexenone and 3-cyclohexenone impurities are generated that cause issues in downstream applications
Solution Approach 1:
The patent converts the harmful enone impurities (2-cyclohexenone and 3-cyclohexenone) into beneficial cyclohexanone product by applying hydrogenation treatment. The hydrogenation catalyst transforms these unwanted byproducts into the desired product, thereby eliminating their harmful effects while maintaining the efficiency of the original oxidation-cleavage process.
Solution Approach 2:
The patent changes the chemical parameters of the reaction system by introducing hydrogenation conditions (hydrogen gas, catalyst, temperature, pressure) to modify the composition of the process stream. This parameter change selectively reduces the concentration of enone impurities while preserving or enhancing cyclohexanone production.
2Quantity of substance
If phenol hydrogenation is used to convert phenol to cyclohexanone, then more cyclohexanone can be produced, but catalyst activity and selectivity are reduced due to poison components and side reactions
Solution Approach 1:
The patent performs preliminary hydrogenation of the enone impurities before the main phenol hydrogenation step. This preliminary action removes catalyst poisons and reduces side reactions that would otherwise occur during phenol hydrogenation, thereby protecting catalyst activity and selectivity while still achieving high cyclohexanone production.
Solution Approach 2:
The patent introduces an intermediary hydrogenation step that acts as a buffer between the oxidation-cleavage process and the phenol hydrogenation process. This intermediary treatment modifies the feed composition to be more suitable for the hydrogenation catalyst, improving overall process reliability.
3Device complexity
If 2-cyclohexenone and 3-cyclohexenone are present in the cyclohexanone product, then the production process is simpler, but downstream applications such as caprolactam production are adversely affected
Solution Approach 1:
The patent converts the harmful enone impurities into beneficial cyclohexanone through hydrogenation, thereby simplifying the overall process by eliminating the need for complex separation units while simultaneously removing the harmful effects on downstream applications.
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 approach effectively abates 2-cyclohexenone and 3-cyclohexenone concentrations, resulting in a cyclohexanone product that is substantially free of these impurities, improving catalyst activity and selectivity, and enhancing the efficiency of cyclohexanone production.
Implementation Method 1
hydrogenation of a feed mixture containing cyclohexanone and 3-cyclohexenone, using a hydrogenation catalyst, to convert 2-cyclohexenone and 3-cyclohexenone into cyclohexanone
Data Source
AI summary
Disclosed are processes for abating 3-cyclohexenone from a feed mixture comprising cyclohexylbenzene, cyclohexanone, phenol, and 3-cyclohexenone and cyclohexanone, comprising feeding the feed mixture to a first distillation column and a hydrogenating a fraction from in the presence of a hydrogenation catalyst under hydrogenation conditions. Hydrogenation can be carried out in a hydrogenation reactor separate from the first distillation column or in a hydrogenation zone disposed inside the first distillation column.