Polyether Polyol Production via Slurry Alkoxylation
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Solution Overview
Problem
The existing 'water process' for producing high functionality polyether polyols from solid polyhydroxyl compounds like sucrose requires a dewatering step, which consumes time and energy, and results in reduced batch size due to excess water and formation of difunctional glycols.
Innovation Solution
A batch process that maintains a slurry of polyhydroxyl compounds, water, and alkali metal hydroxide at elevated temperatures without sufficient water to dissolve the compounds, allowing for the direct addition of alkylene oxide to produce polyether polyols without a dewatering step, thereby reducing energy consumption and glycol formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If sufficient water is used to dissolve sucrose completely, then the sucrose becomes reactive and can undergo alkoxylation, but the batch size is reduced and difunctional glycols are formed
Solution Approach 1:
The patent changes the physical state parameter of sucrose from dissolved liquid phase to suspended solid phase. By maintaining sucrose as undissolved solid particles in the water slurry, the system achieves reactivity through solid-liquid interface reactions while preventing the formation of difunctional glycols that occur when sucrose is fully dissolved. This parameter change resolves the contradiction between ensuring reactivity and maintaining large batch size.
2Quantity of substance
If a dewatering step is employed to remove excess water, then glycol formation is reduced and batch size can be increased, but significant time and energy are consumed
Solution Approach 1:
The patent extracts or removes the harmful dewatering step from the process. By designing the reaction to proceed directly in the water slurry without requiring intermediate water removal, the process eliminates the energy-intensive distillation operation while still achieving reduced glycol formation through the solid suspension mechanism.
Solution Approach 2:
The patent enables continuous alkoxylation reaction without interrupting the process for dewatering. The reaction proceeds continuously in the water slurry medium, maintaining productive action throughout without the stops and energy losses associated with traditional dewatering-interrupted batch processes.
3Quantity of substance
If a dewatering step is employed to remove excess water, then glycol formation is reduced and batch size can be increased, but significant time is consumed
Solution Approach 1:
The patent extracts or removes the harmful dewatering step from the process. By designing the reaction to proceed directly in the water slurry medium, the process eliminates the time-consuming distillation operation while still achieving reduced glycol formation through the solid suspension mechanism.
Solution Approach 2:
The patent enables continuous alkoxylation reaction without interrupting the process for dewatering. The reaction proceeds continuously in the water slurry medium, maintaining productive action throughout without the stops and time losses associated with traditional dewatering-interrupted batch processes.
4Reliability
If excess water is present during alkoxylation, then sucrose can dissolve and react, but the reactor volume is wasted and batch size is reduced
Solution Approach 1:
The patent changes the physical state parameter of sucrose from dissolved liquid phase to suspended solid phase. This allows the system to maintain high sucrose concentration in the reactor volume without requiring excessive water for dissolution, thereby improving reactor volume utilization while preserving reactivity through the solid-liquid interface.
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 enables the production of polyether polyols with desired functionalities and viscosities without the need for additional materials, reducing energy consumption and increasing batch size, while eliminating the dewatering step and associated inefficiencies.
Implementation Method 1
providing a slurry that: (i) has a temperature of from 80°C to 150°C
Implementation Method 2
water present in an amount of at least 0.09 grams of water per gram of the polyhydroxyl compound and less than the amount necessary to solubilize all of the polyhydroxyl compound
Implementation Method 3
an alkali metal hydroxide
Data Source
Figure 1
Figure 2
AI summary
Batch "water processes" for producing high functionality polyether polyols from polyhydroxyl compounds that are solid at ambient conditions, such as is the case with sucrose, are disclosed. The disclosed processes avoid use of an intermediate dewatering step. The polyether polyols produced by the process can be especially useful for producing rigid polyurethane foams.