4-Hydroxy-TEMPO (TEMPOL / H-TEMPO)
Chemical Name: 4-Hydroxy-2,2,6,6-tetramethylpiperidin-1-oxyl
Molecular Formula: C₉H₁₈NO₂
CAS Number: 2226-96-2
A key functionalized derivative of TEMPO featuring both a stable nitroxyl radical and reactive hydroxyl group. Serves as a versatile antioxidant, catalyst, spin label, and crucial intermediate for synthesizing specialty chemicals.

Technical Specifications
Discover the technical specifications of our 4-Hydroxy-TEMPO (TEMPOL / H-TEMPO) products.
Chemical Identity
| Chemical Name | 4-Hydroxy-2,2,6,6-tetramethylpiperidin-1-oxyl |
| Synonyms | H-TEMPO, TEMPOL, 4-Hydroxy-TEMPO, 4-Hydroxy-2,2,6,6-tetramethylpiperidinooxy |
| CAS Number | 2226-96-2 |
| EC Number | 218-760-9 |
| Molecular Formula | C₉H₁₈NO₂ |
| Molecular Weight | 172.24 g/mol |

VUP Specifications (Standard Grade)
| Property | Specification |
|---|---|
| Appearance | Orange or reddish-orange crystalline solid/powder |
| Purity | ≥98.0 % wt |
Note: Specifications that are provided above are typical values and should not be considered as guaranteed analysis.
Key Features & Benefits
Discover the unique advantages of VUP's 4-Hydroxy-TEMPO (TEMPOL / H-TEMPO) for your applications.
Functionalized Stable Radical
Combines unique properties of TEMPO nitroxyl radical with a hydroxyl group, allowing for further chemical modification and enhanced solubility.
Key Inhibitor Intermediate
Serves as direct precursor for VUP's VUPIN range of liquid polymerization inhibitors, demonstrating significant industrial relevance.
Versatile Research Tool
Widely used as water-soluble antioxidant, catalyst in oxidation reactions, and spin label probe in EPR spectroscopy applications.
Building Block Potential
Hydroxyl group provides reactive site for synthesizing other functionalized TEMPO derivatives or incorporating nitroxyl moiety into larger molecules.
Pilot Scale Production
Manufactured at VUP's dedicated pilot plant facility ensuring availability for larger scale R&D, inhibitor production, and industrial applications.
High Purity Quality
VUP's production capabilities deliver high purity suitable for demanding applications including research and specialty chemical synthesis.
Applications
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Polymerization Inhibitor Synthesis
Key raw material for producing formulated liquid polymerization inhibitors like the VUPIN range used in petrochemicals and monomer stabilization applications.
Catalysis & Oxidation
Used as catalyst or co-catalyst in selective oxidation reactions, offering different solubility and reactivity profiles compared to standard TEMPO.
EPR Spectroscopy
Utilized as a spin label probe to study molecular structure, dynamics, and environments in biophysical and chemical research applications.
Antioxidant Research
Employed as a water-soluble antioxidant standard or protective agent in biochemical and cell-based studies investigating oxidative stress mechanisms.
Product Information & Technical Documents
Essential information and documentation for 4-Hydroxy-TEMPO (TEMPOL / H-TEMPO)
Product Identification
Key product details and identifiers
Technical Documents
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Technical Data Sheet (TDS)
Complete technical specifications, physical properties, and application information for 4-Hydroxy-TEMPO (TEMPOL / H-TEMPO)
Safety Data Sheet (SDS)
Safety information, handling procedures, and regulatory details for 4-Hydroxy-TEMPO (TEMPOL / H-TEMPO)
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Frequently Asked Questions
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