Caprolactam (CPL) is an organic compound with the formula (CH2)5C(O)NH. This colourless solid is a lactam (a cyclic amide) of caproic acid. Global demand for this compound is approximately five million tons per year, and the vast majority is used to make Nylon 6 filament, fiber, and plastics.[2]
Caprolactam was first described in the late 1800s when it was prepared by the cyclization of ε-aminocaproic acid, the product of the hydrolysis of caprolactam. World demand for caprolactam was estimated to reach five million tons per year for 2015. 90% of caprolactam produced is used to make filament and fiber, 10% for plastics, and a small amount is used as a chemical intermediate.[2] Due to its commercial significance, many methods have been developed for the production of caprolactam. It was estimated that 90% of all caprolactam is synthesised from cyclohexanone (1), which is first converted to its oxime (2). Treatment of this oxime with acid induces the Beckmann rearrangement to give caprolactam (3):[2]
The immediate product of the acid-induced rearrangement is the bisulfate salt of caprolactam. This salt is neutralized with ammonia to release the free lactam and cogenerate ammonium sulfate. In optimizing the industrial practices, much attention is directed toward minimizing the production of ammonium salts.[2]
The other major industrial route involves formation of the oxime from cyclohexane using nitrosyl chloride, and this method accounts for 10% of world production.[2] The advantage of this method is that cyclohexane is less expensive than cyclohexanone.
Other paths to caprolactam include the depolymerization of waste Nylon 6, and the reaction of caprolactone with ammonia.[2] At bench scale, the reaction between cyclohexanone with hydrazoic acid to give caprolactam in the Schmidt reaction has been reported.[3]
In situ anionic polymerization is employed for cast nylon production where conversion from ε-caprolactam to Nylon 6 takes place inside a mold. In conjunction with endless fiber processing the term thermoplastic resin transfer molding (T-RTM) is often used.
Caprolactam is also used in the synthesis of several pharmaceutical drugs including pentylenetetrazol, meptazinol, and laurocapram.
Safetyedit
Caprolactam is an irritant and is mildly toxic, with an LD50 of 1.1 g/kg (rat, oral). In 1991, it was included on the list of hazardous air pollutants by the U.S. Clean Air Act of 1990. It was subsequently removed from the list in 1996 at the request of the manufacturers.[4] In water, caprolactam hydrolyzes to aminocaproic acid, which is used medicinally.
As of 2016 caprolactam had the unusual status of being the only chemical in the International Agency for Research on Cancer's lowest hazard category, Group 4: "probably not carcinogenic to humans".[5]
The production of caprolactam can produce nitrous oxide as a by-product, a highly potent greenhouse gas. Emissions differ significantly due to different production processes and inconsistent use of emission abatement technology. A study commissioned by the German Federal Ministry for Economic Affairs and Climate Action estimates emissions between 9 kg of nitrous oxide per ton of caprolactam and almost zero. [7]
Nitrous oxide emissions from caprolactam production are unregulated in most countries. Unlike other chemical production processes, nitrous oxide emissions from caprolactam production are not included in the European Union Emissions Trading System. [8]
^NIOSH Pocket Guide to Chemical Hazards, CDC, retrieved November 8, 2013
^"Mitigation potentials for emissions of nitrous oxide from chemical industry in industrialised countries world-wide" (PDF). Öko-Institut. March 2023. Retrieved 2023-10-17.
^Böck, Hanno (2023-09-28). "The avoidable Super-Greenhouse-Gas from Fertilizer, Nylon, and Vitamin B3 production". Industry Decarbonization Newsletter. Retrieved 2023-10-17.
April 14, 2024
caprolactam, organic, compound, with, formula, this, colourless, solid, lactam, cyclic, amide, caproic, acid, global, demand, this, compound, approximately, five, million, tons, year, vast, majority, used, make, nylon, filament, fiber, plastics, namespreferred. Caprolactam CPL is an organic compound with the formula CH2 5C O NH This colourless solid is a lactam a cyclic amide of caproic acid Global demand for this compound is approximately five million tons per year and the vast majority is used to make Nylon 6 filament fiber and plastics 2 Caprolactam NamesPreferred IUPAC name Azepan 2 oneOther names 1 Aza 2 cycloheptanone2 Azacycloheptanonee CaprolactamCapron PK4Cyclohexanone iso oximeExtrom 6NHexahydro 2 azepinoneHexahydro 2H azepin 2 one 9CI HexanolactamHexano 6 lactamAminocaproic lactamIdentifiersCAS Number 105 60 2 Y3D model JSmol Interactive imageBeilstein Reference 106934ChEBI CHEBI 28579 YChEMBL ChEMBL276218 YChemSpider 7480 YECHA InfoCard 100 003 013EC Number 203 313 2Gmelin Reference 101802KEGG C06593 YPubChem CID 7768UNII 6879X594Z8 YCompTox Dashboard EPA DTXSID4020240InChI InChI 1S C6H11NO c8 6 4 2 1 3 5 7 6 h1 5H2 H 7 8 YKey JBKVHLHDHHXQEQ UHFFFAOYSA N YInChI 1 C6H11NO c8 6 4 2 1 3 5 7 6 h1 5H2 H 7 8 Key JBKVHLHDHHXQEQ UHFFFAOYAFSMILES O C1NCCCCC1PropertiesChemical formula C 6H 11N OMolar mass 113 160 g mol 1Appearance White solidDensity 1 01 g cm3Melting point 69 2 C 156 6 F 342 3 K Boiling point 270 8 C 519 4 F 544 0 K at 1013 25 hPaSolubility in water 866 89 g l 22 C Vapor pressure 8 10 8 mmHg 20 C 1 HazardsGHS labelling PictogramsSignal word WarningHazard statements H302 H315 H319 H332 H335Precautionary statements P261 P264 P270 P271 P280 P301 P312 P302 P352 P304 P312 P304 P340 P305 P351 P338 P312 P321 P330 P332 P313 P337 P313 P362 P403 P233 P405 P501Flash point 125 C 257 F 398 K Explosive limits 1 4 8 0 1 NIOSH US health exposure limits PEL Permissible none 1 Except where otherwise noted data are given for materials in their standard state at 25 C 77 F 100 kPa Y verify what is Y N Infobox references Contents 1 Synthesis and production 2 Uses 3 Safety 4 Climate impact 5 ReferencesSynthesis and production editCaprolactam was first described in the late 1800s when it was prepared by the cyclization of e aminocaproic acid the product of the hydrolysis of caprolactam World demand for caprolactam was estimated to reach five million tons per year for 2015 90 of caprolactam produced is used to make filament and fiber 10 for plastics and a small amount is used as a chemical intermediate 2 Due to its commercial significance many methods have been developed for the production of caprolactam It was estimated that 90 of all caprolactam is synthesised from cyclohexanone 1 which is first converted to its oxime 2 Treatment of this oxime with acid induces the Beckmann rearrangement to give caprolactam 3 2 nbsp The immediate product of the acid induced rearrangement is the bisulfate salt of caprolactam This salt is neutralized with ammonia to release the free lactam and cogenerate ammonium sulfate In optimizing the industrial practices much attention is directed toward minimizing the production of ammonium salts 2 The other major industrial route involves formation of the oxime from cyclohexane using nitrosyl chloride and this method accounts for 10 of world production 2 The advantage of this method is that cyclohexane is less expensive than cyclohexanone Other paths to caprolactam include the depolymerization of waste Nylon 6 and the reaction of caprolactone with ammonia 2 At bench scale the reaction between cyclohexanone with hydrazoic acid to give caprolactam in the Schmidt reaction has been reported 3 nbsp Uses editAlmost all caprolactam produced goes into the manufacture of Nylon 6 The conversion entails a ring opening polymerization nbsp Nylon 6 is widely used in fibers and plastics In situ anionic polymerization is employed for cast nylon production where conversion from e caprolactam to Nylon 6 takes place inside a mold In conjunction with endless fiber processing the term thermoplastic resin transfer molding T RTM is often used Caprolactam is also used in the synthesis of several pharmaceutical drugs including pentylenetetrazol meptazinol and laurocapram Safety editCaprolactam is an irritant and is mildly toxic with an LD50 of 1 1 g kg rat oral In 1991 it was included on the list of hazardous air pollutants by the U S Clean Air Act of 1990 It was subsequently removed from the list in 1996 at the request of the manufacturers 4 In water caprolactam hydrolyzes to aminocaproic acid which is used medicinally As of 2016 caprolactam had the unusual status of being the only chemical in the International Agency for Research on Cancer s lowest hazard category Group 4 probably not carcinogenic to humans 5 Currently there is no official permissible exposure limit set for workers handling caprolactam in the United States The recommended exposure limit is set at 1 mg m3 over an eight hour work shift for caprolactam dusts and vapors The short term exposure limit is set at 3 mg m3 for caprolactam dusts and vapors 6 Climate impact editThe production of caprolactam can produce nitrous oxide as a by product a highly potent greenhouse gas Emissions differ significantly due to different production processes and inconsistent use of emission abatement technology A study commissioned by the German Federal Ministry for Economic Affairs and Climate Action estimates emissions between 9 kg of nitrous oxide per ton of caprolactam and almost zero 7 Nitrous oxide emissions from caprolactam production are unregulated in most countries Unlike other chemical production processes nitrous oxide emissions from caprolactam production are not included in the European Union Emissions Trading System 8 References edit a b c NIOSH Pocket Guide to Chemical Hazards 0097 National Institute for Occupational Safety and Health NIOSH a b c d e f Josef Ritz Hugo Fuchs Heinz Kieczka William C Moran Caprolactam Ullmann s Encyclopedia of Industrial Chemistry Weinheim Wiley VCH doi 10 1002 14356007 a05 031 pub2 ISBN 978 3527306732 Eric J Kantorowski Mark J Kurth 2000 Expansion to Seven Membered Rings Tetrahedron 56 26 4317 4353 doi 10 1016 S0040 4020 00 00218 0 EPA Modifications To The 112 b 1 Hazardous Air Pollutants Agents Classified by the IARC Monographs PDF International Agency for Research on Cancer February 22 2016 p 395 Retrieved 21 October 2016 NIOSH Pocket Guide to Chemical Hazards CDC retrieved November 8 2013 Mitigation potentials for emissions of nitrous oxide from chemical industry in industrialised countries world wide PDF Oko Institut March 2023 Retrieved 2023 10 17 Bock Hanno 2023 09 28 The avoidable Super Greenhouse Gas from Fertilizer Nylon and Vitamin B3 production Industry Decarbonization Newsletter Retrieved 2023 10 17 Retrieved from https en wikipedia org w index php title Caprolactam amp oldid 1180535951, wikipedia, wiki, book, books, library,
