Buffered Hydrogen Peroxide Oxidation of Alcohols to Pure Ketones
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Solution Overview
Problem
Existing methods for preparing ketones by oxidizing alcohols with hydrogen peroxide suffer from low pH issues, making them unsuitable for acid-labile starting compounds and leading to low yield and purity, along with significant secondary component formation.
Innovation Solution
The reaction is conducted in the presence of a solvent, catalyst, and buffer, with controlled pH using a base during hydrogen peroxide addition, allowing acid-labile compounds to react effectively, enhancing yield and purity while minimizing secondary components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the known oxidation method using hydrogen peroxide, sodium tungstate dihydrate and hydrogen sulfate-based phase-transfer catalyst is employed, then ketones can be prepared, but the low pH causes acid-labile starting compounds to be unsuitable and reduces yield and purity
Solution Approach 1:
The patent changes the pH parameter from acidic (known method) to neutral or slightly basic (invention method) by using different buffer systems. This parameter change makes the reaction suitable for acid-labile starting compounds while improving product purity and yield. The use of carbonate buffers, phosphate buffers, or borate buffers instead of acidic conditions directly addresses both the adaptability and purity concerns.
Solution Approach 2:
The patent introduces buffer systems (carbonate buffers, phosphate buffers, borate buffers) as intermediaries to control the reaction pH. These buffers act as mediators between the oxidizing agents and the acid-labile starting compounds, preventing direct acidic conditions while maintaining effective oxidation. This intermediary approach resolves the contradiction by protecting sensitive compounds while enabling the oxidation reaction to proceed with high purity.
2Productivity
If the known oxidation method is used, then ketones are produced, but secondary components are significantly formed reducing overall purity
Solution Approach 1:
The patent changes multiple parameters simultaneously: pH (from acidic to neutral/basic), temperature (controlled at 20-40°C), and oxidizing agent selection (sodium hypochlorite, calcium hypochlorite, or hydrogen peroxide with buffer). These parameter changes work together to minimize secondary component formation while maintaining high ketone yield and purity.
Solution Approach 2:
The patent converts potentially harmful strong oxidizing conditions into beneficial controlled oxidation by using buffer systems. The buffers tame the harshness of oxidizing agents like sodium hypochlorite or hydrogen peroxide, transforming what would be damaging conditions into selective, high-yield oxidation that minimizes unwanted side reactions and secondary components.
3Adaptability or versatility
If acid-labile starting compounds are used in known methods, then reaction cannot proceed effectively, but in the invention method these compounds react outstandingly well
Solution Approach 1:
The patent fundamentally changes the pH parameter from acidic to neutral or slightly basic, which directly enables acid-labile starting compounds to participate in the oxidation reaction. This parameter change expands the scope of suitable starting materials while maintaining high reaction efficiency, as the mild conditions prevent decomposition of sensitive compounds.
Solution Approach 2:
The buffer systems serve as protective intermediaries that create a safe chemical environment for acid-labile compounds. These buffers mediate between the oxidizing agents and sensitive starting materials, allowing the reaction to proceed efficiently without exposing the acid-labile compounds to damaging acidic conditions.
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 higher yield and purity of ketones, enabling their direct use in further reactions without purification, particularly for producing hydantoins, and is suitable for acid-labile starting materials.
Implementation Method 1
The preparation of ketones by oxidation of alcohols can be accomplished by various methods that have long been known. In Chem. Com. 2003, 16, 1977, JACS, 1997, 119, 12386 and Bull. Chem. Soc. Japan, 72(10), 1999, 2287-2306, ketones are prepared by reacting alcohols with hydrogen peroxide as oxidant
Implementation Method 2
ketones are prepared by reacting alcohols with hydrogen peroxide as oxidant, sodium tungstate dihydrate as catalyst
Data Source
AI summary
The present invention relates to a novel method for preparing compounds of the formula (II) by reacting compounds of the formula (I) with hydrogen peroxide in the presence of a solvent, in the presence of a catalyst, in the presence of a buffer and optionally in the presence of a base.