Microchannel Polyol Synthesis for Bio-Based Polyurethane
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Solution Overview
Problem
The current preparation of polyurethane polyol relies on petrochemical resources, leading to environmental concerns and inefficiencies, and the existing ring-opening reaction process for epoxy vegetable oil is uncontrollable, resulting in cross-linking and high viscosity issues, which limits the production of high-quality bio-based polyurethane products.
Innovation Solution
A microchannel-based method is employed to prepare a polyurethane polyol by dissolving 2,3-epoxybutane and triethylene glycol with an acid catalyst, followed by a ring-opening reaction with epoxy vegetable oil, and subsequent addition polymerization with epoxypropane and an alkaline catalyst, controlling flow rates and concentrations to minimize cross-linking and achieve a stable product.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If traditional ring-opening reaction process is used for epoxy vegetable oil, then polyurethane polyol can be produced, but cross-linking and high viscosity occur making the process uncontrollable
Solution Approach 1:
The patent changes the reaction parameters by using a two-stage process: first conducting ring-opening reaction at lower temperature (60-80°C) to avoid cross-linking, then performing addition polymerization at higher temperature (80-100°C). This parameter change resolves the contradiction by controlling the reaction conditions to prevent unwanted side reactions while maintaining product formation.
Solution Approach 2:
The patent segments the reaction process into two distinct stages: Stage 1 for ring-opening reaction and Stage 2 for addition polymerization. Each stage has specific temperature, time, and reagent addition parameters. This segmentation allows independent optimization of each reaction step, preventing cross-linking in the first stage while achieving desired molecular weight in the second stage.
2Object-affected harmful factors
If vegetable oil is used as raw material to replace petrochemical polyol, then environmental friendliness and renewability improve, but cross-linking side reactions occur due to complicated raw material components
Solution Approach 1:
The patent performs preliminary action by conducting the ring-opening reaction first to convert epoxy groups to hydroxyl groups, creating a more stable intermediate product. Only after this preliminary transformation is complete does the patent proceed to addition polymerization. This preliminary action prevents cross-linking side reactions by establishing a controlled reaction pathway before introducing reagents that could cause unwanted cross-linking.
Solution Approach 2:
The patent uses triethylene glycol as an intermediary substance in the ring-opening reaction. This intermediary facilitates the conversion of epoxy vegetable oil to hydroxyl-containing compounds without causing cross-linking. The intermediary reagent controls the reaction pathway, allowing the complex vegetable oil components to be transformed systematically rather than reacting directly and uncontrollably.
3Productivity
If high concentration of reactants is used to increase reaction intensity, then productivity improves, but side reactions increase and product quality decreases
Solution Approach 1:
The patent maintains continuity of useful action by conducting reactions in sequential stages without interruption. The ring-opening reaction proceeds continuously to completion, followed immediately by continuous addition polymerization. This continuous approach ensures high productivity while maintaining quality because each stage is allowed to proceed to optimal conversion before the next stage begins, preventing side reactions that would occur with batch-wise or interrupted processing.
Solution Approach 2:
The patent employs periodic action by alternating between two distinct reaction phases with different temperature, time, and reagent conditions. The first periodic phase (ring-opening) uses milder conditions, followed by the second periodic phase (polymerization) with more intense conditions. This periodic alternation allows the system to achieve high overall conversion and productivity while maintaining product quality by matching reaction intensity to the specific requirements of each reaction stage.
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 method produces a low-viscosity, high-quality polyurethane polyol that can replace traditional polyether polyols, offering a simple, energy-efficient process with fewer side reactions and stable product formation, suitable for producing polyurethane elastomers without further treatment.
Implementation Method 1
dissolving 2,3-epoxybutane and an acid catalyst in an inert solvent to obtain a solution A; dissolving triethylene glycol in an inert solvent to obtain a solution B; respectively and simultaneously pumping the solution A and the solution B into a first micromixer in a microchannel reaction device for mixing, and then introducing the mixture into a first microreactor for reaction to obtain a reaction solution containing a hydroxyl compound
Implementation Method 2
respectfully and simultaneously pumping the solution C and an effluent of the first microreactor into a second micromixer in the microchannel reaction device for mixing while carrying out step (2), and then introducing the mixture into a second microreactor for ring-opening reaction to obtain a reaction solution containing a vegetable oil polyol
Implementation Method 3
dissolving epoxypropane and an alkaline catalyst in an inert solvent to obtain a solution E; and respectively and simultaneously pumping the solution D and the solution E into a tank reactor for addition polymerization reaction, thereby obtaining the polyurethane polyol
Data Source
AI summary
A method for preparing a polyol comprises the following steps of: (1) dissolving 2,3 -epoxybutane and an acid catalyst in an inert solvent to obtain a solution A; dissolving triethylene glycol in an inert solvent to obtain a solution B; and dissolving epoxy vegetable oil in an inert solvent to obtain a solution C; (2) respectively and simultaneously pumping the solutions A and B into a first micromixer for mixing; (3) pumping the solution C and an effluent of the first microreactor into a second micromixer for mixing while carrying out step (2); and (4) dissolving the vegetable oil polyol in an inert solvent to obtain a solution D; dissolving epoxypropane and an alkaline catalyst in an inert solvent to obtain a solution E; and pumping the solution D and the solution E into a tank reactor for reaction, thereby obtaining the polyol.