Hexitol Dehydration via Mixed Acid Catalyst for Anhydrosugar Alcohol
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Solution Overview
Problem
Conventional methods for preparing anhydrosugar alcohol from hexitol face challenges such as low conversion rates and purification yields due to high costs of catalysts and production of polymer by-products, limiting industrial utilization.
Innovation Solution
A method involving the dehydration of hexitol using a mixed acid of sulfuric acid and a sulfur-containing acid salt, such as p-toluenesulfonic acid, methanesulfonic acid, or aluminum sulfate, under controlled temperature and vacuum conditions to achieve high conversion rates and purification yields.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If inorganic acid such as sulfuric acid or hydrochloric acid is used for dehydration of hexitol, then production cost is reduced and ease of manufacture is improved, but purification yield decreases due to production of large amounts of polymer by-products
Solution Approach 1:
The patent uses a composite catalyst system consisting of solid acid catalyst (such as ion exchange resin or zeolite) combined with inorganic acid (sulfuric acid or hydrochloric acid). This composite approach combines the advantages of both catalyst types: the solid acid provides high selectivity and reduces polymer by-product formation, while the inorganic acid ensures high conversion rate and works effectively with hexitol. The synergistic effect resolves the contradiction between ease of manufacture and purification yield.
2Manufacturing precision
If cation exchange resins or zeolites are used for dehydration of hexitol, then purification yield is improved, but production cost increases and conversion rate decreases
Solution Approach 1:
The patent merges the functions of solid acid catalyst and inorganic acid catalyst into a single reaction system. By combining cation exchange resin (or zeolite) with sulfuric acid (or hydrochloric acid), the system achieves both high purification yield (from the solid acid's selectivity) and high conversion rate (from the inorganic acid's reactivity), while the inorganic acid's cost-effectiveness offsets the higher cost of the solid acid catalyst.
3Productivity
If conventional single acid catalyst is used for dehydration of hexitol, then conversion rate may be achieved, but purification yield decreases due to polymer by-product formation
Solution Approach 1:
The patent employs a composite catalyst system where solid acid (ion exchange resin or zeolite) and inorganic acid (sulfuric acid or hydrochloric acid) work together. The solid acid component provides high selectivity that suppresses polymer by-product formation, thereby maintaining high purification yield, while the inorganic acid component ensures high conversion rate of hexitol. This composite approach resolves the contradiction between productivity and manufacturing precision.
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 achieves an anhydrosugar alcohol with a conversion rate of 80% or higher and a purification yield of 65% or more, reducing production costs and polymer by-product formation, thus enhancing industrial applicability.
Implementation Method 1
dehydration of hexitol with a mixed acid of first acid and second acid wherein the first acid is sulfuric acid, and the second acid is at least one sulfur-containing acid
Implementation Method 2
dehydration of hexitol with a mixed acid of first acid and second acid
Implementation Method 3
under controlled temperature and vacuum conditions
Data Source
AI summary
Disclosed is a method for the preparation of an anhydrosugar alcohol using a starch-derived hexitol such as sorbitol or mannitol. Anhydrosugar alcohol is in the form of a diol having two hydroxyl groups in the molecule thereof and has a very high utility value as a physical property modifier which can be used primarily in plastics. Representative examples of anhydrosugar alcohols include isosorbide and isomannide. These anhydrosugar alcohols are capable of increasing a glass transition temperature of and improving strength of PET, polyesters, polycarbonates, etc., and are therefore highly valuable as biodegradable environmentally-friendly bioplastics.