Solvent-Free Polyether Polyol Synthesis via Base Catalysis
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Solution Overview
Problem
Existing processes for producing polyether polyols from solid starter compounds at room temperature face challenges in achieving clear and homogeneous end products without using solvents or suspension aids, particularly when producing block-structured polyether polyols with high oxyethylene unit content.
Innovation Solution
A solvent-free process involving the base-catalyzed addition of ethylene oxide and propylene oxide to solid starter compounds, where the ethylene oxide block is metered under specific temperature and catalyst conditions to achieve blocks with at least 75% oxyethylene units, ensuring clear and homogeneous polyether polyols are produced.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If solvents or suspension aids are used to carry out alkylene oxide addition reactions with solid starter compounds, then the reaction can proceed smoothly, but the reactor volume is consumed by the solvent and the end products may show clouding or inhomogeneities
Solution Approach 1:
The invention extracts and eliminates the solvent or suspension aid from the reaction system. By carrying out the alkylene oxide addition reaction without solvents or suspension aids, the reactor volume is fully utilized for the reaction mixture, and the end products are obtained without clouding or inhomogeneities that would result from solvent removal or suspension aid separation.
2Ease of operation
If water is used as suspension/solvent for solid starter compounds, then the reaction can be interrupted and excess water separated by distillation, but end products with lower functionalities are created and additional time and energy are required for distillation
Solution Approach 1:
The invention removes water from the reaction system entirely, replacing it with no suspension aid or solvent. This eliminates the need for distillation steps to remove excess water, reducing both time and energy consumption while maintaining the ability to control the reaction through the specified temperature and catalyst conditions.
Solution Approach 2:
The invention changes the reaction parameters by specifying precise temperature ranges (70-180°C) and catalyst amounts (0.01-5 mol% relative to starter compound) to enable solvent-free reaction conditions. These parameter changes allow the reaction to proceed effectively without water, eliminating the need for subsequent distillation operations.
3Ease of manufacture
If solvents are used to carry out the reaction, then the reaction can proceed with solid starter compounds, but product hygiene and sustainability are compromised
Solution Approach 1:
The invention extracts and eliminates solvents from the reaction system, achieving solvent-free alkylene oxide addition reactions with solid starter compounds. This improves product hygiene by removing potential solvent residues and enhances sustainability by eliminating the need for solvent recovery and disposal operations.
4Stability of the object's composition
If solvents are used in the reaction, then the reaction mixture can be homogeneous, but valuable reactor volume is occupied by the solvent
Solution Approach 1:
The invention removes solvents from the reaction system, achieving solvent-free conditions where the reactor volume is fully utilized for the reaction mixture. The specified temperature and catalyst conditions ensure proper mixing and homogeneity without requiring solvent mediation.
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 eliminates the need for solvents and suspension aids, resulting in economically and environmentally friendly production of clear, homogeneous polyether polyols suitable for various polyurethane materials, with increased reactivity towards isocyanates due to high primary end groups.
Implementation Method 1
base-catalyzed addition of ethylene oxide and propylene oxide to solid starter compounds
Data Source
AI summary
The present invention relates to a process for the production of polyether polyols by base-catalyzed addition of alkylene oxides (epoxides) to starter compounds with Zerewitinoff-active hydrogen atoms that are solid at room temperature, which is particularly characterized by the fact that optically clear and/or homogeneous products are obtained even without solvents.