Menthol Hydrogenation Catalyst Composition
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current methods for producing menthol often result in mixtures of diastereomers, leading to complex purification processes and the formation of undesirable by-products like menthone and neoiso-menthol, with a need for more efficient and cost-effective industrial-scale production of essentially diastereomerically pure menthol.
Innovation Solution
A catalytic hydrogenation process using a catalyst composition of 30-70% nickel, 15-45% zirconium, 5-30% copper, and 0.1-10% molybdenum, applied to racemic or optically active isopulegol, which allows for the production of racemic or optically active menthol with high chemical yield and minimal diastereomer formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional hydrogenation catalysts (nickel, copper, zirconium) are used to hydrogenate isopulegol, then menthol can be produced, but a mixture of diastereomers is formed requiring complex purification processes
Solution Approach 1:
The patent modifies the catalyst composition by introducing molybdenum as a fourth component with specific weight ratios (Ni: 30-70%, Zr: 15-45%, Cu: 5-30%, Mo: 0.1-10%). This parameter change in catalyst composition enables selective hydrogenation that produces menthol with high diastereomeric purity (≥97%) while maintaining high productivity, resolving the contradiction between production efficiency and product purity.
Solution Approach 2:
The patent employs a composite catalyst system combining four metals (nickel, zirconium, copper, and molybdenum) with specific synergistic ratios. This composite catalyst material achieves both high conversion rates and high stereoselectivity, simultaneously improving productivity and manufacturing precision by preventing diastereomer formation through the coordinated action of multiple metal centers.
2Productivity
If hydrogenation is carried out to produce menthol, then chemical yield can be improved, but undesirable by-products like menthone and neoiso-menthol are formed
Solution Approach 1:
The patent optimizes the catalyst composition parameters by incorporating molybdenum at 0.1-10% weight ratio, which fundamentally changes the reaction selectivity. This parameter modification enables the catalyst to distinguish between desired hydrogenation pathways (forming menthol) and unwanted pathways (forming menthone and neoiso-menthol), achieving high chemical yield while suppressing by-product formation.
Solution Approach 2:
The patent converts the potential harm of non-selective hydrogenation (which would produce multiple by-products) into a benefit by using the molybdenum-containing catalyst to achieve high selectivity. The catalyst system transforms the reaction to produce only the desired menthol with minimal by-products, turning a potentially harmful non-selective process into a highly beneficial selective synthesis.
3Ease of manufacture
If existing catalyst systems are used for industrial-scale production, then cost-effectiveness can be maintained, but diastereomer separation processes become necessary increasing complexity
Solution Approach 1:
The patent extracts and eliminates the need for complex purification processes by using a highly selective catalyst that produces menthol with ≥97% diastereomeric purity directly during synthesis. By removing the requirement for subsequent separation operations, the process simplifies the overall manufacturing system while maintaining cost-effectiveness, as the selective catalyst prevents by-product formation rather than requiring removal of by-products.
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 process achieves high chemical and diastereomeric purity of menthol, with minimal formation of undesirable by-products, enabling efficient and cost-effective production of essentially diastereomerically pure menthol on an industrial scale.
Implementation Method 1
catalytic hydrogenation of racemic or optically active isopulegol in the presence of hydrogen and catalysts comprising nickel, copper, zirconium and molybdenum-containing compounds
Implementation Method 2
catalytic hydrogenation of isopulegol to menthol in the presence of a catalyst comprising 30 to 70% by weight of oxygen-containing compounds of nickel, calculated as NiO, 15 to 45% by weight of oxygen-containing compounds of zirconium, calculated as ZrO2, 5 to 30% by weight of oxygen-containing compounds of copper, calculated as CuO and 0.1 to 10% by weight of oxygen-containing compounds of molybdenum, calculated as MoO3
Data Source
AI summary
PF 60020 17 The present invention relates to a process for preparing racemic or optically active menthol by catalytic hydrogenation of racemic or optically active isopulegol in the presence of hydrogen and catalysts which include nickel-, copper-, zirconium- and molybdenum-containing compounds. The present invention 10 specifically relates to a corresponding process for the continuous catalytic hydrogenation of L-isopulegol to L-menthol.