Natural L-menthol Crystallization via Step-wise Cooling
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Solution Overview
Problem
Existing methods for producing I-menthol are time-consuming, require significant manual labor, and struggle with adapting to Good Manufacturing Practice (GMP) regulations due to the handling of mentha oil and I-menthol crystals, leading to impurities that affect the quality and flavor of the final product.
Innovation Solution
A method involving gradual cooling of crude mentha oil in a closed system to crystallize and purify I-menthol, removing residual oil and impurities without human contact, using a crystallizer with automated temperature control and a stripping system to achieve high purity I-menthol in a single crystallization step, reducing production time and facilitating GMP compliance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If traditional crystallization methods are used to produce I-menthol, then high purity (at least 98%) can be achieved, but production time exceeds two weeks to a month
Solution Approach 1:
The traditional multi-step process (initial crystallization, filtration, recrystallization) is segmented and reorganized into a single integrated crystallization step where I-menthol crystals are directly formed in high purity from crude mentha oil, eliminating intermediate purification steps
Solution Approach 2:
The patent applies preliminary action by conducting the crystallization step under optimized conditions (controlled cooling rate, specific temperature range, and anti-solvent addition) that pre-determine the high purity of crystals, eliminating the need for subsequent recrystallization
2Ease of manufacture
If manual handling of mentha oil and I-menthol crystals is performed, then traditional production methods can be executed, but adaptation to GMP regulation becomes difficult
Solution Approach 1:
Manual mechanical handling operations (filtration, transfer, washing) are replaced with automated systems including percolation for solvent removal, centrifugal separation for crystal isolation, and automated drying, enabling GMP-compliant production
Solution Approach 2:
An anti-solvent (isopropanol or ethyl acetate) is introduced as an intermediary substance to facilitate the crystallization process, enabling direct formation of high-purity crystals from crude oil without extensive manual purification steps
3Productivity
If residual liquid mentha oil adheres to I-menthol crystals, then crystallization efficiency is maintained, but sensory profile and quality of I-menthol are adversely affected
Solution Approach 1:
Residual mentha oil and impurities are extracted from the crystal surface through percolation with appropriate solvents and centrifugal separation, removing the harmful adhering liquid while preserving the crystal structure
Solution Approach 2:
The patent changes physical parameters (temperature, solvent composition, flow rate during percolation) to optimize the removal of residual oil from crystals, achieving high purity while maintaining crystallization efficiency
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
The method produces highly pure I-menthol (at least 98% purity) in a shorter timeframe (less than two weeks) with reduced manual handling, enhancing product quality and ease of adaptation to pharmaceutical GMP standards.
Implementation Method 1
crystallizing I-menthol from crude mentha oil by gradual cooling in a container
Implementation Method 2
temperature in the crystallizer is gradually reduced to between about -30°C to about 30°C
Implementation Method 3
passing a fluid over the I-menthol crystals to remove residual oil and impurities
Implementation Method 4
passing a fluid over the I-menthol crystals to remove residual oil and impurities
Implementation Method 5
melting the purified I-menthol crystals to remove I-menthol from the crystallizer as a melt
Implementation Method 6
cooling the melt into a dried, solid I-menthol product
Data Source
AI summary
Embodiments are provided that provide for efficient production of highly pure natural I-menthol. In some embodiments, a method for preparing natural I-menthol involves providing crude mentha oil in a crystallizer and gradually reducing the temperature of the crystallizer in a step-wise manner, thereby producing highly pure crystals in less than two weeks. The methods disclosed herein are suitable for pharmaceutical GMP.