Biphasic Solvent Catalytic Process for Light Naphtha Production
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Solution Overview
Problem
Current methods for converting cellulose into light naphtha are inefficient, requiring multistep processes, high energy inputs, and complex metal catalysts, with low yields and poor selectivity for C5+ alkanes, particularly n-hexane, due to challenges in breaking C-O bonds without forming unwanted byproducts like sorbitol.
Innovation Solution
A biphasic reactor system using an acid catalyst in the aqueous phase and a redox catalyst, such as Ru on carbon modified with HPA, in the organic phase, under hydrogen pressure, to selectively convert cellulose into light naphtha through hydrolysis, dehydration, and hydrogenation, avoiding sorbitol formation and achieving high carbon yields of C5 to C6 alkanes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If multistep processes are used to convert cellulose into light naphtha, then the conversion can be achieved, but the process complexity and energy consumption increase significantly
Solution Approach 1:
The patent combines multiple reaction steps (hydrolysis, dehydration, and hydrogenation) into a single integrated biphasic reactor system. The aqueous phase contains acid catalyst for hydrolysis and dehydration, while the organic phase contains redox catalyst for hydrogenation, allowing all transformations to occur simultaneously in one reactor rather than through separate sequential steps.
Solution Approach 2:
The reaction system is segmented into two distinct phases with specific functions: the aqueous phase handles hydrolysis and dehydration reactions to produce 5-HMF, while the organic phase handles hydrogenation reactions to convert 5-HMF into light naphtha. This segmentation allows each phase to be optimized for its specific function while working together in the same reactor.
2Manufacturing precision
If complex metal catalysts are used to achieve high selectivity, then the yield of C5+ alkanes improves, but the cost and complexity of the catalytic system increases
Solution Approach 1:
Different catalysts are placed in different phases with specific local functions: the acid catalyst in the aqueous phase provides hydrolysis and dehydration activity, while the redox catalyst in the organic phase provides hydrogenation activity. Each catalyst is optimized for its specific local function, achieving high overall selectivity without requiring a single complex multi-functional catalyst.
Solution Approach 2:
The biphasic system acts as an intermediary mechanism that separates catalysts into different phases, allowing each catalyst to operate under optimal conditions without interfering with the other. The phase boundary and mass transfer between phases mediate the overall reaction process, enabling simple catalysts to achieve complex transformation goals.
3Productivity
If high conversion of cellulose is achieved, then the productivity increases, but unwanted byproducts like sorbitol are formed
Solution Approach 1:
The biphasic system uses the organic phase as an intermediary to selectively extract 5-HMF from the aqueous phase and immediately hydrogenate it. This intermediary mechanism prevents 5-HMF from undergoing unwanted side reactions that would lead to sorbitol formation, while maintaining high conversion of cellulose to desired C5+ alkanes.
Solution Approach 2:
The organic phase extracts 5-HMF from the aqueous phase as it forms, removing it from the environment where it could undergo unwanted reduction to sorbitol. This extraction and immediate hydrogenation in the organic phase prevents byproduct formation while maintaining high productivity.
4Productivity
If high loadings of carbohydrate feedstock are used, then the productivity improves, but the separation of products becomes more difficult
Solution Approach 1:
The biphasic system segments products into different phases based on their solubility characteristics: light naphtha products partition into the organic phase while water-soluble byproducts remain in the aqueous phase. This automatic segmentation based on phase affinity simplifies separation even at high feedstock loadings, as the product distribution is driven by thermodynamic partitioning rather than requiring complex separation operations.
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 process achieves high selectivity and yield of light naphtha, primarily composed of n-hexane, n-pentane, and cyclohexane, with over 80% carbon yield, while minimizing energy consumption and avoiding complex metal catalysts, thus providing an efficient and selective route for producing bio-based fuels and chemicals.
Implementation Method 1
the carbohydrate containing feedstock or polymer is hydrolysed and the resulting monosaccharides dehydrated to 5-HMF
Implementation Method 2
the resulting monosaccharides dehydrated to 5-HMF
Implementation Method 3
converting 5-HMF towards the alkanes through several cycles of dehydration/hydrogenation and/or formal hydrodeoxygenation
Implementation Method 4
the organic phase (preferably an alkane) contains a special redox catalyst
Implementation Method 5
converting carbohydrates or carbohydrate containing feedstock, and more preferably cellulose, under hydrogen pressure
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
The patent describes a one-step liquid biphasic catalytic process for converting a carbohydrate-containing feedstock, preferably lignocellulose, to light naphtha (e.g., hexane, pentane, methyl cyclopentane, cyclohexane, etc.) in presence of an acidic reactive aqueous phase and a redox catalyst in the organic extracting/reaction phase. The process provides a cost-effective route for producing light-naphtha components, in presence or not of deoxygenates. The light naphtha components are useful as feedstock for steam and catalytic cracking to produce value-added platform molecules like ethylene and propylene, as precursor for the synthesis of bioaromatics like benzene and as gasoline fuel feedstock, and as fuel additives, (e.g., the concomitantly formed oxygenates) to improve the biological origin of carbon in the fuel.