Producing hexamethylenediamine from caprolactam via 6-aminocapronitrile: a green production technology of the monomer of nylon-66

Hexamethylenediamine (HMDA), a crucial precursor of nylon-66, can be synthesized from caprolactam (CPL) via a two-step route involving CPL ammoniation and 6-aminocapronitrile (ACN) hydrogenation. Based on theoretical calculations and experimental screening, mesoporous alumina was selected which serv...

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Published inGreen chemistry : an international journal and green chemistry resource : GC Vol. 26; no. 15; pp. 8777 - 8784
Main Authors Geng, Kaiyu, Li, Hui, Zhang, Dianzi, Yu, Baowei, Hu, Hongqin, Geng, Jiao, Wu, Youting, Hu, Xingbang
Format Journal Article
LanguageEnglish
Published Cambridge Royal Society of Chemistry 29.07.2024
Subjects
Aluminum oxide
Amides
Ammoniation
Caprolactam
Catalysts
Dehydration
Hydrogenation
Nylon
Ring opening
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Summary:Hexamethylenediamine (HMDA), a crucial precursor of nylon-66, can be synthesized from caprolactam (CPL) via a two-step route involving CPL ammoniation and 6-aminocapronitrile (ACN) hydrogenation. Based on theoretical calculations and experimental screening, mesoporous alumina was selected which served as a highly active and cost-efficient catalyst for CPL ammoniation, catalysing the ring-opening of amides by C–N bond breakage and subsequent amide dehydration to nitrile. A 57.9% CPL conversion and 98.3% ACN selectivity were achieved at 320 °C with stability over 480 hours. The subsequent hydrogenation of ACN using the commercial RANEY® Ni catalyst yielded 100% HMDA, requiring milder conditions and half the hydrogen compared to adiponitrile processes. Overall, this research highlights a green HMDA production pathway, employing CPL as a feedstock.
ISSN:1463-9262
1463-9270
DOI:10.1039/D4GC02268H