Aliphatic Polyester Polyols from Cyclohexane Oxidation Byproducts
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The challenge lies in effectively utilizing and valorizing byproduct streams from cyclohexane oxidation processes in adipic acid and caprolactam manufacturing, which are complex mixtures containing various functional groups, often treated as waste due to the complexity and cost of purification.
Innovation Solution
A process that directly converts cyclohexane oxidation byproducts into aliphatic polyester polyols, which can be used to produce polyurethanes and polyisocyanurates without the need for costly separation of individual monomers, by heating the byproduct mixtures to remove monofunctional components and adding polyhydroxy compounds, followed by distillation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If byproduct streams from cyclohexane oxidation are directly utilized without purification, then production cost is reduced and material valorization is improved, but the complexity of the mixture and presence of interfering components worsens processing difficulty
Solution Approach 1:
The patent extracts and removes interfering byproduct components (such as cyclohexyl hydroperoxide, cyclohexanone, and other oxidation products) from the complex byproduct stream through selective extraction processes. This allows the desired adipic acid and caprolactam to be isolated while eliminating substances that would interfere with subsequent polymerization reactions, thus resolving the contradiction between direct utilization and processing difficulty
Solution Approach 2:
The patent employs parameter changes in the form of controlled oxidation conditions, temperature, and catalyst selection to optimize the conversion of cyclohexane byproducts into valuable polyols and subsequently into polyurethanes and polyisocyanurates. By adjusting oxidation parameters and processing conditions, the patent transforms the complex mixture into usable products while managing the complexity through controlled chemical transformations
2Device complexity
If byproduct streams are treated as waste and burned for fuel value, then processing complexity is minimized, but the functional value and economic potential of the byproducts are lost
Solution Approach 1:
The patent converts the previously harmful or worthless byproduct streams into valuable chemical feedstocks for producing polyols, polyurethanes, and polyisocyanurates. By recognizing the functional groups (alcohol, alkene, carboxylic acid, lactone, ester, and ketone) in the byproducts as resources rather than waste, the patent transforms what would have been discarded material into economically valuable products, thereby converting the 'harm' of complex byproduct formation into the 'benefit' of additional product streams
Solution Approach 2:
The patent demonstrates multi-functionality by showing that the same cyclohexane oxidation byproduct stream can be directed toward multiple valuable outcomes: production of adipic acid for nylon-66, caprolactam for nylon-6, or polyols for polyurethane and polyisocyanurate polymers. This universal utilization approach maximizes the value extraction from a single process stream, preventing functional value loss while maintaining reasonable processing complexity
3Productivity
If cyclohexane oxidation proceeds to high conversion, then yield of desired products is improved, but the formation of interfering byproducts increases and complicates subsequent processing
Solution Approach 1:
The patent applies preliminary action by conducting a water wash extraction step before the main oxidation and processing stages. This preliminary removal of water-soluble byproducts (including cyclohexyl hydroperoxide and other oxidation intermediates) prevents these interfering substances from accumulating during subsequent high-conversion oxidation steps, thereby enabling high productivity while minimizing byproduct interference in the final product streams
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 approach enables the creation of valuable polyurethane and polyisocyanurate polymers from previously underutilized byproduct streams, offering a cost-effective and efficient method to enhance the value of these materials, suitable for various applications such as coatings, sealants, and controlled release fertilizers.
Implementation Method 1
heating the byproduct mixture to remove monofunctional components and water
Implementation Method 2
adding polyhydroxy compounds, followed by distillation
Data Source
Figure 1
AI summary
The invention provides polyester polyol compositions, useful as components of polyurethane and polyisocyanurate polymers, prduced from cyclohexane oxidation reaction byproducts, such as water extracts and non-volatile distillation residues from the reaction. Such byproducts of industrial processes for preparation of adipic acid and caprolactam, important intermediates in the production of various types of nylon, have hitherto largely been used only as fuels. The present invention provides value-added products, methods for making, and methods for using the byproduct-derived polyester polyol compositions. For example, the invention provides polyurethane (PU) and/or polyisocyanurate (PIR) polymers made using the polyol compositions and polyfunctional isocyanates. The PU and PIR polymers can be used as adhesives, binders (e.g., for wood fibers), coatings (e.g., for controlled release fertilizers), and foams.