Cyclohexanone Production via Phenol Hydrogenation and Distillation
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Solution Overview
Problem
The existing processes for producing cyclohexanone from a mixture containing phenol, cyclohexanone, and cyclohexylbenzene face challenges due to yield losses from the conversion of cyclohexylbenzene to bicyclohexane and the formation of cyclohexanol during hydrogenation, which reduces the efficiency of cyclohexanone production.
Innovation Solution
A process involving the hydrogenation of a mixture comprising phenol, cyclohexanone, and cyclohexylbenzene in the liquid phase with a hydrogenation catalyst, under specific temperature and pressure conditions, in a tubular heat exchanger reactor, where hydrogen and phenol are contacted in the presence of the catalyst, and a cooling medium is used to manage the reaction heat, optimizing the conversion of phenol to cyclohexanone while minimizing the formation of byproducts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If hydrogenation is performed on a mixture containing phenol, cyclohexanone, and cyclohexylbenzene, then phenol is converted to cyclohexanone, but cyclohexylbenzene is converted to bicyclohexane and cyclohexanol is formed, causing yield loss
Solution Approach 1:
The process is divided into two separate stages: first, cyclohexylbenzene is converted to phenol and cyclohexanone through oxidation and cleavage; second, only the phenol component is hydrogenated to cyclohexanone. This segmentation prevents the unwanted hydrogenation of cyclohexylbenzene to bicyclohexane and minimizes cyclohexanol formation, thereby resolving the contradiction between productivity and substance loss.
Solution Approach 2:
Before the hydrogenation step, the mixture undergoes preliminary oxidation and cleavage reactions that convert cyclohexylbenzene into phenol and cyclohexanone. This preliminary action ensures that when hydrogenation occurs, the primary reactant is phenol rather than cyclohexylbenzene, thus preventing the formation of bicyclohexane and reducing cyclohexanol byproducts.
2Quantity of substance
If phenol hydrogenation is performed to increase cyclohexanone production, then more cyclohexanone is produced, but side reactions increase and reduce overall process efficiency
Solution Approach 1:
The process utilizes parameter changes in the form of sequential chemical transformations. The oxidation and cleavage steps convert cyclohexylbenzene into phenol and cyclohexanone, changing the chemical composition before hydrogenation. This parameter change ensures that the hydrogenation step acts primarily on phenol rather than cyclohexylbenzene, increasing cyclohexanone yield while minimizing harmful side reactions.
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 enhances the selectivity and efficiency of cyclohexanone production, improving the yield by ensuring that at least 50% of cyclohexylbenzene remains in the liquid phase and 50% of phenol is in the liquid phase during hydrogenation, thereby reducing unwanted side reactions and increasing the production of cyclohexanone.
Implementation Method 1
hydrogenation of a mixture comprising phenol, cyclohexanone, and cyclohexylbenzene in the liquid phase with a hydrogenation catalyst
Implementation Method 2
contacting at least a portion of the phenol with at least a portion of the hydrogen in the hydrogenation reaction zone in the presence of a hydrogenation catalyst
Implementation Method 3
a cooling medium is used to manage the reaction heat
Implementation Method 4
passing a cooling medium through the shell, thereby cooling the reaction mixture inside the tubes
Data Source
Figure 1
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AI summary
Disclosed are processes and systems for making cyclohexanone from a mixture comprising phenol, cyclohexanone, and cyclohexylbenzene, comprising a step of or a device for subjecting at least a portion of the mixture to hydrogenation and a step of or a device for distilling a phenol/cyclohexanone/cyclohexylbenzene mixture to obtain an effluent rich in cyclohexanone.