24:
829:(NMP), a controlled free radical polymerization technique that allows better control over the final molecular weight distribution. The TEMPO free radical can be added to the end of a growing polymer chain, creating a "dormant" chain that stops polymerizing. However, the linkage between the polymer chain and TEMPO is weak, and can be broken upon heating, which then allows the polymerization to continue. Thus, the chemist can control the extent of polymerization and also synthesize narrowly distributed polymer chains.
297:
188:
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33:
773:
564:
668:
806:
The oxidation of TEMPO can be highly selective. It has been proven that secondary alcohols are more likely to be oxidized by TEMPO under an acidic environment. The reason is when in this condition, secondary alcohols are more easily able to provide an H ion.
837:
TEMPO is sufficiently inexpensive for use on a laboratory scale. There is also industrial-scale manufacturer which can provide TEMPO at a reasonable price in large quantity. Structurally related analogues do exist, which are largely based on
451:
423:
810:
In cases where secondary oxidizing agents cause side reactions, it is possible to stoichiometrically convert TEMPO to the oxoammonium salt in a separate step. For example, in the oxidation of
513:
990:
Yonekuta
Yasunori, Oyaizu Kenichi, Nishide Hiroyuki (2007). "Structural Implication of Oxoammonium Cations for Reversible Organic One-electron Redox Reaction to Nitroxide Radicals".
577:
505:
1242:
1181:
1134:
1017:
346:
635:, it has applications in chemistry and biochemistry. TEMPO is used as a radical marker, as a structural probe for biological systems in conjunction with
826:
509:
866:
713:
846:, making it much less expensive. Other alternatives include polymer-supported TEMPO catalysts, which are economic due to their recyclability.
1196:
1081:
1315:
1271:
311:
1158:"Oxidation of Primary Alcohols to Carboxylic Acids with Sodium Chlorite catalyzed by TEMPO and Bleach: 4-Methoxyphenylacetic Acid"
850:
729:
955:
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584:
479:
254:
105:
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901:
854:
717:
709:
Regardless of the reasons for the stability of the radical, the O–H bond in the hydrogenated derivative (the
636:
501:
1285:
Ciriminna, R.; Pagliaro, M. (2010). "Industrial
Oxidations with Organocatalyst TEMPO and Its Derivatives".
442:
183:
1330:
644:
938:
Montanari, F.; Quici, S.; Henry-Riyad, H.; Tidwell, T. T. (2005). "2,2,6,6-Tetramethylpiperidin-1-oxyl".
145:
1335:
1236:
1175:
1128:
1011:
676:
628:
465:
435:
23:
803:, being inert towards secondary alcohols, but the reagent will convert aldehydes to carboxylic acids.
1340:
877:
517:
45:
720:
of about 70 kcal/mol (290 kJ/mol), this bond is about 30% weaker than a typical O–H bond.
792:
758:
739:
683:
292:
71:
747:
485:
682:
The stability of this radical can be attributed to the delocalization of the radical to form a
1223:
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263:
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754:
655:
TEMPO was discovered by
Lebedev and Kazarnowskii in 1960. It is prepared by oxidation of
81:
525:
296:
187:
125:
699:
555:
471:
1324:
710:
408:
398:
176:
1057:
533:
227:
787:)-(+)-2-methylbutanal: 4-Methoxyphenethyl alcohol is oxidized to the corresponding
694:. Additional stability is attributed to the steric protection provided by the four
687:
489:
947:
1107:"A General Synthetic Method for the Oxidation of Primary Alcohols to Aldehydes: (
706:
center adjacent to the aminoxyl would be subject to abstraction by the aminoxyl.
493:
1214:
1157:
1106:
1037:-methoxyphenyl-4-phenyl-2-oxazolin-5-one and 2,2,6,6-Tetramethyl-1-piperidinyl-
772:
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156:
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703:
214:
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872:
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667:
554:
Except where otherwise noted, data are given for materials in their
1156:
Zhao, M. M.; Li, J.; Mano, E.; Song, Z. J.; Tschaen, D. M. (2005).
679:. The reactive radical is well shielded by the four methyl groups.
1091:
666:
238:
116:
104:
94:
529:
702:. These methyl groups serve as inert substituents, whereas any
280:
686:
N–O bond. The stability is reminiscent of the stability of
849:
Industrial-scale examples of TEMPO-like compounds include
842:(TEMPOL). This is produced from acetone and ammonia, via
1076:. Vol. 2. John Wiley & Sons. pp. 705–750.
1074:
1031:
Zanocco, A. L.; Canetem, A. Y.; Melendez, M. X. (2000).
822:
is first oxidized to the oxoammonium tetrafluoroborate.
403:
36 to 38 °C (97 to 100 °F; 309 to 311 K)
320:
InChI=1S/C9H18NO/c1-8(2)6-5-7-9(3,4)10(8)11/h5-7H2,1-4H3
572:
330:
InChI=1/C9H18NO/c1-8(2)6-5-7-9(3,4)10(8)11/h5-7H2,1-4H3
671:
Structure of TEMPO. The N–O distance is 1.284 Å..
779:One typical reaction example is the oxidation of (
1105:Anelli, P. L.; Montanari, F.; Quici, S. (1990).
971:Lebedev, O. L.; Kazarnovskii, S. N. (1960). "".
631:is a red-orange, sublimable solid. As a stable
226:
80:
940:Encyclopedia of Reagents for Organic Synthesis
902:"2,2,6,6-Tetramethylpiperidine-1-oxyl (TEMPO)"
8:
1241:: CS1 maint: multiple names: authors list (
1180:: CS1 maint: multiple names: authors list (
1133:: CS1 maint: multiple names: authors list (
1016:: CS1 maint: multiple names: authors list (
1033:"A Kinetic Study of the Reaction between 2-
738:as a catalyst for the oxidation of primary
601:(2,2,6,6-tetramethylpiperidin-1-yl)oxidanyl
59:(2,2,6,6-Tetramethylpiperidin-1-yl)oxidanyl
1287:Organic Process Research & Development
295:
186:
164:
15:
1056:
1045:Boletín de la Sociedad Chilena de Química
922:
827:nitroxide-mediated radical polymerization
262:
1072:Galli, C. (2009). "Nitroxyl radicals".
892:
867:1-Hydroxy-2,2,6,6-tetramethylpiperidine
714:1-hydroxy-2,2,6,6-tetramethylpiperidine
597:(2,2,6,6-Tetramethylpiperidin-1-yl)oxyl
351:
316:
291:
50:(2,2,6,6-Tetramethylpiperidin-1-yl)oxyl
1234:
1197:"Detailed study about TEMPO oxidation"
1173:
1126:
1009:
177:
833:Industrial applications and analogues
323:Key: QYTDEUPAUMOIOP-UHFFFAOYSA-N
144:
124:
7:
675:The structure has been confirmed by
791:in a system of catalytic TEMPO and
333:Key: QYTDEUPAUMOIOP-UHFFFAOYAP
217:
1215:"2,6-Octadienal, 3,7-dimethyl-, (2
643:, and as a mediator in controlled
14:
869:, the reduced derivative of TEMPO
851:hindered amine light stabilizers
799:. TEMPO oxidations also exhibit
724:Application in organic synthesis
716:) TEMPO–H is weak. With an O–H
562:
441:
31:
22:
1272:"TEMPO-LISKON industrial-scale"
1058:10.4067/S0366-16442000000100016
795:and a stoichiometric amount of
761:as the stoichiometric oxidant,
730:Oxoammonium-catalyzed oxidation
558:(at 25 °C , 100 kPa).
825:TEMPO can also be employed in
769:-oxoammonium salt from TEMPO.
639:spectroscopy, as a reagent in
1:
948:10.1002/047084289X.rt069.pub2
783:)-(−)-2-methyl-1-butanol to (
746:. The actual oxidant is the
657:2,2,6,6-tetramethylpiperidine
979:(5): 1631–1635. CAN 55:7792.
1357:
1144:, vol. 8, p. 367
727:
393:156.25 g/mol
942:. John Wiley & Sons.
855:polymerisation inhibitors
684:two-center three-electron
552:
422:
417:
362:
342:
307:
64:
56:
44:
39:
30:
21:
718:bond dissociation energy
480:Precautionary statements
698:groups adjacent to the
637:electron spin resonance
1213:; Merbouh, N. (2005).
1111:)-(+)-2-Methylbutanal"
776:
672:
645:radical polymerization
413:sublimes under vacuum
775:
734:TEMPO is employed in
677:X-ray crystallography
670:
663:Structure and bonding
629:heterocyclic compound
924:10.1055/s-2001-12332
900:Barriga, S. (2001).
611:with the formula (CH
603:, commonly known as
46:Preferred IUPAC name
1004:10.1246/cl.2007.866
881:-Hydroxyphthalimide
793:sodium hypochlorite
759:sodium hypochlorite
18:
973:Zhur. Obshch. Khim
777:
673:
585:Infobox references
354:CC1(CCCC(N1)(C)C)C
16:
1299:10.1021/op900059x
1224:Organic Syntheses
1163:Organic Syntheses
1142:Collected Volumes
1116:Organic Syntheses
1083:978-0-470-51261-6
820:4-acetamido-TEMPO
763:hypochlorous acid
751:-oxoammonium salt
736:organic synthesis
641:organic synthesis
609:chemical compound
593:Chemical compound
591:
590:
541:Safety data sheet
466:Hazard statements
276:CompTox Dashboard
106:Interactive image
1348:
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1260:. Sigma-Aldrich.
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844:triacetone amine
801:chemoselectivity
692:nitrogen dioxide
633:aminoxyl radical
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370:Chemical formula
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840:4-hydroxy-TEMPO
835:
797:sodium chlorite
789:carboxylic acid
765:generates the
755:catalytic cycle
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1293:(1): 245–251.
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1211:Bobbitt, J. M.
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1199:. LISKON-CHEM.
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998:(7): 866–867.
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514:P305+P351+P338
506:P303+P361+P353
502:P301+P330+P331
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711:hydroxylamine
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547:External MSDS
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409:Boiling point
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1237:cite journal
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1176:cite journal
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1012:cite journal
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688:nitric oxide
681:
674:
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604:
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596:
595:
457:
424:
239:RTECS number
146:ChEMBL606971
65:Identifiers
57:Other names
1341:Piperidines
651:Preparation
452:Signal word
363:Properties
184:100.018.081
126:CHEBI:32849
1325:Categories
1092:2008046989
992:Chem. Lett
957:0471936235
917:(4): 563.
887:References
728:See also:
436:Pictograms
389:Molar mass
264:VQN7359ICQ
157:ChemSpider
93:3D model (
72:CAS Number
744:aldehydes
627:NO. This
510:P304+P340
427:labelling
383:NO
246:TN8991900
205:219-888-8
197:EC Number
82:2564-83-2
861:See also
816:geranial
812:geraniol
740:alcohols
418:Hazards
1258:"TEMPO"
1041:-oxide"
910:Synlett
753:. In a
607:, is a
578:what is
576: (
228:2724126
215:PubChem
166:2006285
1090:
1080:
954:
873:TEMPOL
696:methyl
573:verify
570:
543:(SDS)
458:Danger
347:SMILES
137:ChEMBL
40:Names
17:TEMPO
1316:TEMPO
1170:: 195
1123:: 212
905:(PDF)
757:with
605:TEMPO
312:InChI
117:ChEBI
95:JSmol
1243:link
1231:: 80
1182:link
1135:link
1088:LCCN
1078:ISBN
1018:link
952:ISBN
915:2001
853:and
690:and
619:(CMe
534:P501
530:P405
526:P363
522:P321
518:P310
498:P280
494:P273
490:P264
486:P260
472:H314
255:UNII
1295:doi
1219:)-"
1053:doi
1000:doi
944:doi
919:doi
818:,
814:to
742:to
599:or
425:GHS
281:EPA
218:CID
1327::
1291:14
1289:.
1239:}}
1235:{{
1229:82
1227:.
1221:.
1178:}}
1174:{{
1168:81
1166:.
1160:.
1139:;
1131:}}
1127:{{
1121:69
1119:.
1113:.
1086:.
1049:45
1047:.
1043:.
1014:}}
1010:{{
996:36
994:.
977:30
975:.
950:.
913:.
907:.
857:.
704:CH
659:.
647:.
532:,
528:,
524:,
520:,
516:,
512:,
508:,
504:,
500:,
496:,
492:,
488:,
429::
381:18
1301:.
1297::
1274:.
1247:.
1245:)
1217:E
1186:.
1184:)
1146:.
1137:)
1109:S
1094:.
1061:.
1055::
1039:N
1035:p
1020:)
1006:.
1002::
960:.
946::
927:.
921::
879:N
785:S
781:S
767:N
749:N
625:2
623:)
621:2
617:3
615:)
613:2
568:Y
379:H
377:9
375:C
283:)
279:(
97:)
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