Co-Dehydration Polyol Synthesis for Rigid Foam
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Solution Overview
Problem
Current methods for producing polyols through the co-dehydration of sugar alcohols and polyols often result in products with high isosorbide content that crystallize, making them difficult to handle and use in applications like rigid polyurethane foams, due to limited control over isosorbide levels and viscosity.
Innovation Solution
A process involving the acid-catalyzed co-dehydration of sugar alcohols with specific polyols, such as sorbitol and glycerol, to produce a reaction product with controlled isosorbide content (25-65% by weight) and oligomer levels, maintaining a liquid state at room temperature, and adjusting the viscosity through diluent addition and alkoxylation to create a polyol suitable for rigid polyurethane foam production.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the co-dehydration of sugar alcohol is performed to produce high isosorbide content product, then the purity of isosorbide is improved, but the product crystallizes and becomes difficult to handle
Solution Approach 1:
The patent applies parameter changes by controlling the isosorbide content within a specific range (25-65 weight percent) rather than maximizing it to high purity. This parameter optimization prevents crystallization while maintaining sufficient isosorbide content for polymer applications, resolving the contradiction between purity and handling ease
Solution Approach 2:
The patent creates a composite reaction product containing isosorbide, unreacted sugar alcohol, and oligomers in controlled proportions. This composite composition prevents crystallization while maintaining the desired isosorbide content for polymer synthesis, effectively resolving the handling difficulty associated with high-purity crystalline isosorbide
2Strength
If the isosorbide content is increased to improve polymer performance, then the polymer properties are improved, but the viscosity of the polyol increases
Solution Approach 1:
The patent optimizes the isosorbide content parameter to a balanced range (25-65 weight percent) that provides sufficient polymer performance while preventing excessive viscosity increase. This parameter control ensures the polyol remains processable while delivering improved polymer properties
Solution Approach 2:
The patent utilizes the natural composition of the co-dehydration reaction product, which inherently contains a mixture of isosorbide, unreacted sugar alcohol, and oligomers. This natural composition distribution provides an optimal balance between polymer performance and viscosity without requiring additional processing steps
3Productivity
If the co-dehydration reaction is performed to maximize isosorbide yield, then the productivity is improved, but the control over isosorbide levels and product composition is lost
Solution Approach 1:
The patent implements feedback control by monitoring and adjusting reaction conditions (catalyst amount, temperature, reaction time, reactant ratio) to achieve the desired isosorbide content range. This feedback mechanism ensures both high productivity and precise control over isosorbide levels and product composition
Solution Approach 2:
The patent employs dynamic control of reaction parameters during the co-dehydration process. By adjusting catalyst concentration, temperature, and reaction time based on desired product specifications, the system dynamically optimizes both yield and composition control, resolving 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 process effectively controls isosorbide content and viscosity, preventing crystallization and enabling the production of a liquid polyol suitable for rigid polyurethane foams with improved handling and performance characteristics.
Implementation Method 1
a process involving the acid-catalyzed co-dehydration of sugar alcohols with specific polyols
Implementation Method 2
the co-dehydration of a sugar alcohol and a reactant polyol having an number average functionality (Fn) of from two to three
Data Source
AI summary
A reaction product of the co-dehydration of a sugar alcohol and a reactant polyol having a number average hydroxyl functionality less than 4.0 is disclosed. In some aspects the sugar alcohol comprises mannitol, sorbitol, xylitol, erythritol, or mixtures thereof. In some preferred aspects the sugar alcohol comprises sorbitol. In some aspects the reactant polyol has an average molecular weight of from 40 to 500 Daltons. In some aspects, the reaction product may be suitable for the manufacture of polyisocyanurate foam. In some aspects the reaction product may be mixed with diluent polyols, such as diols, glycols, ethylene glycol, diethylene glycol, dipropylene glycol, propylene glycol, polyethylene glycol, polypropylene glycol and mixtures thereof.