Chromium Ester Catalyst Preparation via Reactive Distillation
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Solution Overview
Problem
Existing methods for producing chromium-based deperoxidation catalysts for alkyl hydroperoxides are not productive and generate chromium-containing effluents harmful to the environment, lacking control and stability in industrial-scale implementation.
Innovation Solution
A process involving the dissolution of chromic anhydride in water with a tertiary alcohol and a hydrocarbon solvent, followed by reactive distillation under reduced pressure to produce a stable ester of chromic acid catalyst, such as di-tert-butyl chromate, which is free of water and chromium precipitates, allowing for controlled and efficient deperoxidation of cyclohexyl hydroperoxide to cyclohexanol and cyclohexanone.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If chromic anhydride is directly applied to an organic solution comprising a tertiary alcohol and a hydrocarbon solvent, then the catalyst can be produced, but the process is not well controllable on an industrial scale and presents the risk of generating an unstable mixture
Solution Approach 1:
The patent applies preliminary action by first dissolving chromic anhydride in water to create a stable aqueous solution before introducing it to the organic phase. This pre-preparation step ensures controlled reaction conditions and prevents direct contact between chromic anhydride and the organic solvent, eliminating the risk of unstable mixture formation while maintaining industrial-scale productivity
Solution Approach 2:
The patent uses water as an intermediary medium to dissolve chromic anhydride before the chromic acid reacts with the tertiary alcohol in the organic phase. This intermediary step provides better control over the reaction process, allowing industrial-scale production while maintaining stability and preventing runaway reactions
2Stability of the object's composition
If water is not removed from the reaction medium, then the chromic ester solution may form solid deposits during storage, but removing water requires additional processing steps
Solution Approach 1:
The patent employs phase transition by distilling off water from the reaction medium under reduced pressure at temperatures between 20-40°C. This controlled evaporation removes water to prevent solid deposit formation during storage, while the reduced pressure conditions allow water removal at low temperatures to avoid decomposing the chromic ester catalyst
Solution Approach 2:
The patent changes physical parameters by conducting the water removal process under reduced pressure at controlled temperatures (20-40°C). These parameter changes enable efficient water elimination to prevent instability, while the温和 conditions protect the catalyst integrity, balancing solution stability with process simplicity
3Ease of manufacture
If existing methods are used to produce the catalyst, then the catalyst can be synthesized, but chromium-containing effluents harmful to the environment are generated
Solution Approach 1:
The patent converts the potentially harmful chromium waste into a beneficial concentrated catalyst product. By using reactive distillation to simultaneously synthesize the chromic ester and remove water, the process concentrates the chromium into the desired catalyst form rather than producing waste effluents, thus converting what would be pollution into the final useful product
Solution Approach 2:
The patent recovers chromium from what would otherwise be waste effluents by concentrating it into the chromic ester catalyst through reactive distillation. The process discards only water and minor byproducts while recovering and concentrating the valuable chromium component into the final catalyst product, eliminating harmful chromium-containing effluents
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 stable, productive, and efficient chromium ester solution with high yield, preventing chromium precipitation and producing distilled water free of chromium, enabling effective deperoxidation with over 90% conversion of cyclohexyl hydroperoxide without environmental harm.
Implementation Method 1
React the alcohol and chromic anhydride to obtain an alkyl chromate
Implementation Method 2
by placing the reaction medium under reduced pressure at a temperature between 20 and 40 °C and distilling off the water contained in the reaction medium
Implementation Method 3
the water is removed from the reaction medium by distillation in the form of an azeotrope formed in particular with the hydrocarbon solvent
Implementation Method 4
the cyclohexyl hydroperoxide is decomposed by deperoxidation into cyclohexanone and cyclohexanol, in the presence of a catalyst comprising as main catalytic element chromium
Data Source
AI summary
The invention relates to a method for preparing a deperoxidation catalyst including chromium as the main catalytic element thereof. The invention relates specifically to a method for preparing an organic solution of a chromium acid ester, said solution being used as a catalyst in the step of deperoxidation of an alkyl peroxide in the method for manufacturing cyclohexanol / cyclohexanone by means of oxidising cyclohexane.