Terpinolene Epoxide Isomerization Using Carboxylic Acid Esters
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Solution Overview
Problem
Existing processes for producing terpene alcohols like limonene-4-ol and terpinene-4-ol from terpinolene epoxide using copper catalysts suffer from low yields and high formation of undesired by-products, particularly when using certain solvents like ethanol.
Innovation Solution
A process involving isomerization and/or hydrogenation of terpinolene epoxide in the presence of a copper catalyst and carboxylic acid esters as solvents, such as ethyl acetate, to selectively produce limonene-4-ol and terpinene-4-ol with improved yields and reduced by-product formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional solvents like ethanol are used in the copper catalyst process, then the reaction proceeds, but undesired by-products are formed in high amounts and yields are low
Solution Approach 1:
The patent changes the solvent parameter from conventional solvents (ethanol, cyclohexane, 1,4-butanediol) to carboxylic acid esters (ethyl acetate, n-propyl acetate, isopropyl acetate, n-butyl acetate, isobutyl acetate, sec-butyl acetate, tert-butyl acetate). This parameter change fundamentally alters the reaction environment, leading to suppressed side reactions and improved selectivity towards the desired terpene alcohols while maintaining acceptable reaction rates.
2Ease of manufacture
If the reaction is performed in a single step with copper catalyst, then the process is simple, but the yield is insufficient and by-products are high
Solution Approach 1:
The patent maintains the single-step copper catalyst process simplicity while improving yield through solvent parameter change. The carboxylic acid ester solvent system enables the single-step process to achieve yields of limonene-4-ol and/or terpinene-4-ol of at least 79%, thereby resolving the contradiction between process simplicity and productivity.
3Productivity
If conventional solvents are used, then the reaction proceeds, but selectivity towards desired terpene alcohols is low
Solution Approach 1:
The patent achieves high selectivity (at least 79%) towards limonene-4-ol and/or terpinene-4-ol by changing the solvent parameter to carboxylic acid esters. This solvent change suppresses side reactions such as dehydration and decomposition of terpinolene-4,8-epoxide, thereby minimizing by-product formation and maximizing desired product selectivity.
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 high yields and selectivity for limonene-4-ol and terpinene-4-ol in a single step, minimizing side reactions and allowing for potential use of the reaction product in subsequent steps without extensive purification, thus being industrially simple and environmentally friendly.
Implementation Method 1
via an isomerization and/or hydrogenation reaction in the presence of a copper catalyst
Implementation Method 2
via an isomerization and/or hydrogenation reaction in the presence of a copper catalyst
Implementation Method 3
in the presence of at least one copper catalyst
Data Source
AI summary
The present invention relates to a process for preparing a mixture of terpene alcohols comprising limonene-4-ol and terpinene-4-ol from terpinolene epoxide via an isomerization and/or hydrogenation reaction in the presence of a copper catalyst.