Laurolactam Synthesis with Catalyst Removal and Recrystallization
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Solution Overview
Problem
Existing methods for synthesizing laurolactam, such as Bechmann rearrangement, are complex and produce large amounts of by-products, require costly equipment for by-product treatment, and result in low-purity laurolactam due to residual catalysts, limiting anionic polymerization efficiency.
Innovation Solution
A simplified process involving Bechmann rearrangement of cyclododecanone oxime using a catalyst system of cyanuric chloride and zinc chloride, followed by solvent treatment with a good and poor solvent to remove catalysts, and recrystallization to achieve high-purity laurolactam, which is then polymerized anionically to produce polylaurolactam.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If conventional Bechmann rearrangement using concentrated sulfuric acid and oleum is used, then laurolactam can be synthesized, but a large amount of ammonium sulfate by-product is produced requiring complex treatment equipment
Solution Approach 1:
The patent changes the chemical parameters of the catalyst system from concentrated sulfuric acid and oleum to cyanuric chloride and zinc chloride, which fundamentally alters the reaction pathway and by-product profile. This parameter change eliminates the formation of large amounts of ammonium sulfate by-product while maintaining high laurolactam production efficiency
Solution Approach 2:
The patent employs a catalyst system that does not require complex treatment equipment and can be easily removed through simple filtration and washing processes. The cyanuric chloride-zinc chloride catalyst system is designed to be easily separable, eliminating the need for expensive and complex by-product treatment infrastructure
2Manufacturing precision
If conventional purification methods including distillation and heavy removal are used, then solvent is removed, but a small amount of catalyst remains in the final product decreasing polymerization activity
Solution Approach 1:
The patent employs a multi-stage purification process that extracts and removes the catalyst system from the laurolactam product. The process includes filtration to remove solid catalyst particles, washing with water to remove soluble catalyst components, and recrystallization to achieve high purity laurolactam free from catalyst contamination that would otherwise poison the anionic polymerization
Solution Approach 2:
The patent performs preliminary purification steps immediately after the Bechmann rearrangement reaction, including filtration and washing, to remove the catalyst system before the laurolactam is used for anionic polymerization. This preliminary action prevents catalyst contamination from affecting the subsequent polymerization reaction
3Productivity
If conventional catalyst systems are used, then Bechmann rearrangement can proceed, but the process is significantly complicated and requires high acid content
Solution Approach 1:
The patent changes the fundamental parameters of the catalyst system from strong mineral acids (sulfuric acid, oleum) to organic acid derivatives (cyanuric chloride) combined with metal halides (zinc chloride). This parameter change simplifies the overall process by eliminating the need for specialized acid-resistant equipment and complex safety protocols while maintaining high reaction efficiency
Solution Approach 2:
The patent introduces cyanuric chloride as an intermediary catalyst that facilitates the Bechmann rearrangement through a different mechanism than traditional strong acids. The cyanuric chloride-zinc chloride system acts as a milder alternative that achieves the same transformation with simpler process requirements and fewer equipment constraints
4Reliability
If solvents that do not react with concentrated sulfuric acid and oleum are selected, then the reaction can proceed, but the selection of solvent is limited
Solution Approach 1:
The patent changes the chemical environment parameters by replacing the strongly acidic catalyst system with a milder cyanuric chloride-zinc chloride system. This parameter change expands the solvent selection flexibility to include common organic solvents like dichloromethane, chloroform, and carbon tetrachloride that would be incompatible with concentrated sulfuric acid and oleum, while still maintaining reaction stability
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 process effectively removes catalysts and solvents, producing high-purity laurolactam with a conversion rate of 98-99.9% and selectivity of 97-99.5%, enabling efficient anionic polymerization to high-molecular-weight polylaurolactam.
Implementation Method 1
synthesizing laurolactam by Bechmann rearrangement of cyclododecanone oxime under a catalyst system
Implementation Method 2
mixing the laurolactam synthesized in step a) with a good solvent and removing the catalyst system
Implementation Method 3
mixing the laurolactam from which the catalyst system has been removed in step b) with a poor solvent and performing recrystallization
Implementation Method 4
Step a) may further include removing the solvent by distilling the synthesized laurolactam
Implementation Method 5
a method of preparing polylaurolactam with a high conversion rate, using an anionic polymerization reaction of the synthesized laurolactam
Data Source
AI summary
Provided are a method of preparing laurolactam including: a) synthesizing laurolactam by Bechmann rearrangement of cyclododecanone oxime under a catalyst system, b) mixing the laurolactam synthesized in a) with a good solvent and removing the catalyst system, and c) mixing the laurolactam from which the catalyst system has been removed in b) with a poor solvent and performing recrystallization, a synthesis device thereof, a laurolactam composition prepared therefrom, and a method of preparing polylaurolactam using the laurolactam composition.