2,2,6,6-Tetramethylpiperidinooxy
[CAS# 2564-83-2]

Identification

• Classification: Organic raw materials >> Heterocyclic compound
• Name: 2,2,6,6-Tetramethylpiperidinooxy
• Synonyms: 2,2,6,6-Tetramethylpiperidine 1-oxyl; TEMPO
• Molecular Formula: C₉H₁₈NO
• Molecular Weight: 156.25
• CAS Registry Number: 2564-83-2
• EC Number: 219-888-8
• SMILES: CC1(CCCC(N1[O])(C)C)C

Properties

• Melting point: 36-40 °C
• Boiling point: 193 °C
• Flash point: 67 °C

Safety Data

• Hazard Symbols: GHS05;GHS07 Danger
• Risk Statements: H314-H318-H335-H412
• Safety Statements: P260-P261-P264-P264+P265-P271-P273-P280-P301+P330+P331-P302+P361+P354-P304+P340-P305+P354+P338-P316-P317-P319-P321-P363-P403+P233-P405-P501

Hazard Classification

Hazard	Class	Category Code	Hazard Statement
Skin corrosion	Skin Corr.	1C	H314
Skin corrosion	Skin Corr.	1B	H314
Serious eye damage	Eye Dam.	1	H318
Chronic hazardous to the aquatic environment	Aquatic Chronic	3	H412
Skin irritation	Skin Irrit.	2	H315
Eye irritation	Eye Irrit.	2	H319
Specific target organ toxicity - single exposure	STOT SE	3	H335
Acute toxicity	Acute Tox.	4	H332
Chronic hazardous to the aquatic environment	Aquatic Chronic	2	H411
Acute toxicity	Acute Tox.	1	H310

• Transport Information: UN 3263

Discovery and Applications

2,2,6,6-Tetramethylpiperidinooxy, abbreviated as TEMPO, was discovered in the late 1960s by German chemists. Initially, it was synthesized as a stable free radical for use in studying reaction mechanisms. However, its unique properties soon garnered attention beyond academia.

TEMPO acts as a highly efficient catalyst in oxidation reactions, particularly in the conversion of alcohols to carbonyl compounds. Its ability to selectively oxidize primary alcohols to aldehydes and secondary alcohols to ketones makes it invaluable in organic synthesis.

TEMPO is extensively used in polymer chemistry for the synthesis of functional polymers with controlled structures and properties. By mediating radical polymerization reactions, it enables the production of polymers with tailored molecular weights and architectures, essential for applications in materials science and drug delivery.

In the paper industry, TEMPO is employed as a bleaching agent to improve the brightness and strength of pulp fibers. Its mild oxidation properties allow for selective removal of lignin and other impurities from wood pulp without damaging cellulose fibers, leading to the production of high-quality paper products.

TEMPO exhibits antioxidant properties, making it useful in biomedical applications for scavenging free radicals and protecting cells from oxidative stress. Research suggests its potential in mitigating oxidative damage associated with neurodegenerative diseases and age-related disorders.

TEMPO-modified electrodes are utilized in electrochemical sensors for detecting various analytes, including biomolecules, pollutants, and pharmaceuticals. Its stable redox behavior and high sensitivity enable precise and selective detection.

TEMPO-based compounds are employed as food additives for preserving freshness and extending shelf life. By inhibiting lipid oxidation, they prevent rancidity and maintain the quality of packaged foods, such as oils, fats, and processed meats.

References

2022. Electrocatalytic oxidative upgrading of biomass platform chemicals: from the aspect of reaction mechanism. Chemical communications (Cambridge, England), 58(8).
DOI: 10.1039/d1cc06254a

2020. TEMPO-oxidized bacterial cellulose nanofiber membranes as high-performance separators for lithium-ion batteries. Carbohydrate Polymers, 229.
DOI: 10.1016/j.carbpol.2019.115570

2009. Mechanistic insight into TEMPO-inhibited polymerisation: simultaneous determination of oxygen and inhibitor concentrations by EPR. Organic & Biomolecular Chemistry, 7(13).
DOI: 10.1039/b905893a