Cyclic Lactam Depolymerization Using Ammonium Phosphate Salts
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Solution Overview
Problem
Existing methods using phosphoric acids for depolymerizing polyamide resins result in low yields of cyclic lactams.
Innovation Solution
A depolymerization reaction of polyamide resin using an ammonium phosphate salt, specifically represented by formula (b), is employed, which acts as a catalyst and solvent, allowing for efficient production of cyclic lactams through reactive distillation without the use of low-boiling-point solvents like water or alcohols.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If phosphoric acid is used as a catalyst in the depolymerization of polyamide resins, then the depolymerization reaction can proceed, but the yield of cyclic lactam is low
Solution Approach 1:
The invention changes the chemical parameter of the catalyst from phosphoric acid to ammonium phosphate salt, which fundamentally alters the reaction mechanism and improves cyclic lactam yield. This parameter change transforms the catalytic system to one that promotes depolymerization more effectively while minimizing side reactions.
Solution Approach 2:
The invention uses ammonium phosphate salt as a catalyst that replicates and enhances the functionality of phosphoric acid while avoiding its limitations. The ammonium phosphate salt serves as a superior catalyst copy that maintains the necessary acidic properties for depolymerization while improving product yield through its unique chemical characteristics.
2Ease of manufacture
If conventional depolymerization methods are used, then polyamide resin can be converted to cyclic lactam, but the process requires complex purification steps and high energy input
Solution Approach 1:
The invention extracts and removes the need for complex purification steps by using ammonium phosphate salt catalyst that produces cleaner reaction products. The catalytic system is designed to minimize impurity formation, allowing direct isolation of cyclic lactam without extensive purification operations.
Solution Approach 2:
The invention employs a catalyst system that eliminates the need for expensive and energy-intensive purification equipment and processes. The ammonium phosphate salt enables a simpler, more economical production pathway that reduces both capital investment and operational energy costs.
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 method achieves a higher yield of cyclic lactams with simplified purification processes, reducing energy costs and material requirements.
Implementation Method 1
a depolymerization reaction of a polyamide resin using an ammonium phosphate salt
Implementation Method 2
the depolymerization reaction is carried out while performing reactive distillation
Data Source
Figure 1
AI summary
Provided is a method for producing a cyclic lactam that can produce a cyclic lactam with good yield, as well as an apparatus for producing a cyclic lactam. A method for producing a cyclic lactam, wherein a polyamide resin comprising a repeating unit represented by formula (a) is subjected to a depolymerization reaction using a compound represented by formula (b). In formula (a), n1 is an integer of 3 to 22. The value of n1 may vary for each repeating unit. In formula (b), R1 to R3 are each independently a hydrogen atom or an aliphatic group having 1 to 22 carbon atoms; at least one of R1 to R3 is an aliphatic group having 5 to 22 carbon atoms; and the aliphatic group may each independently comprise at least one of the groups represented by formulae (b×1) to (b×4).