Piperazine

Athanor · official

C₄H₁₀N₂ · 86.14 g/mol

Also called diethylenediamine, hexahydropyrazine

Rings

Open in Athanor

Drawn from its SMILES with RDKit

DangerCauses severe skin burns and eye damage · May cause an allergic skin reaction · May cause allergy or asthma symptoms or breathing difficulties if inhaled · Suspected of damaging fertility; Suspected of damaging the unborn child

Names and identifiers

IUPAC name: piperazine
Synonyms: diethylenediamine, hexahydropyrazine, Diethylenediamine
+ 37 more
1,4-Diazacyclohexane, Hexahydropyrazine, Piperazin, Antiren, Piperazidine, Diethyleneimine, Dispermine, Lumbrical, Pipersol, Eraverm, 1,4-Piperazine, Wurmirazin, Uvilon, Piperazine, anhydrous, Worm-A-Ton, 1,4-Diethylenediamine, Pyrazine hexahydride, Hexahydro-1,4-diazine, Pyrazine, hexahydro-, Piperazine (USP), DTXSID1021164, NSC-474, 1RTM4PAL0V, Piperazine [USP], FEMA NO. 4250, CHEBI:28568, P02CB01, DTXCID701164, 1,4 Diazacyclohexane, Vermizine, Ascalix, Ectodyne, Expelix, Wormex, Ins umuline rapide, 1,4 Piperazine, RefChem:6143
Molecular formula: C₄H₁₀N₂
Empirical formula: C₂H₅N
Molecular weight: 86.14 g/mol
Exact mass: 86.08440
CAS number: 110-85-0
PubChem CID: 4837
Canonical SMILES: C1CNCCN1
Isomeric SMILES: C1CNCCN1
InChI: InChI=1S/C4H10N2/c1-2-6-4-3-5-1/h5-6H,1-4H2
InChIKey: GLUUGHFHXGJENI-UHFFFAOYSA-N
Molfile

Names, InChI and the identifiers from PubChem, retrieved 2026-10-14.

Physical properties

TemperaturePressureDensity

Appearance: Colorless, transparent, needle-like crystals[4]
5 values
From Hazardous Substances Data Bank (HSDB), the most authoritative source here.
Value As written Source
– Needle-like white or colorless crystals. Shipped as a solid or suspended in a liquid medium. Very corrosive to skin, eyes and mucous membranes. Solid turns dark when exposed to light. Flash point 190 °F. Used as a corrosion inhibitor and as an insecticide. [1] CAMEO Chemicals
– Large Crystals; CBI; Liquid [2] EPA Chemical Data Reporting (CDR)
– HYGROSCOPIC COLOURLESS CRYSTALS OR WHITE FLAKES WITH PUNGENT ODOUR. [3] ILO-WHO International Chemical Safety Cards (ICSCs)
– WHITE TO SLIGHTLY OFF-WHITE LUMPS OR FLAKES [4] Hazardous Substances Data Bank (HSDB)cites Osol, A. and J.E. Hoover, et al. (eds.). Remington's Pharmaceutical Sciences. 15th ed. Easton, Pennsylvania: Mack Publishing Co., 1975., p. 1175
–shown Colorless, transparent, needle-like crystals [4] Hazardous Substances Data Bank (HSDB)cites Lewis, R.J. Sr.; Hawley's Condensed Chemical Dictionary 14th Edition. John Wiley & Sons, Inc. New York, NY 2001., p. 881
Odor: Typical amine odor[4]
2 values
From Hazardous Substances Data Bank (HSDB), the most authoritative source here.
Value As written Source
–shown Typical amine odor [4] Hazardous Substances Data Bank (HSDB)cites Eller K, Henkes E; Ullmann's Encyclopedia of Industrial Chemistry. 7th ed. (2005). NY, NY: John Wiley & Sons; Amines, Aliphatic. Online Posting Date: June 15, 2000.
– AMMONIACAL ODOR [4] Hazardous Substances Data Bank (HSDB)cites Osol, A. and J.E. Hoover, et al. (eds.). Remington's Pharmaceutical Sciences. 15th ed. Easton, Pennsylvania: Mack Publishing Co., 1975., p. 1075
Melting point: 106 °C[3]
3 values
3 of 3 sources agree on it (most common value).
Value As written Source
106 °C 223 °F (NTP, 1992) [1] CAMEO Chemicalscites National Toxicology Program, Institute of Environmental Health Sciences, National Institutes of Health (NTP). 1992. National Toxicology Program Chemical Repository Database. Research Triangle Park, North Carolina.
106 °Cshown 106 °C [3] ILO-WHO International Chemical Safety Cards (ICSCs)
106 °C 106 °C [5] PAC Chemical Database, U.S. Department of Energy
Boiling point: 146 °C[3]
3 values
3 of 3 sources agree on it (most common value).
Value As written Source
146 °C 295 °F at 760 mmHg (NTP, 1992) [1] CAMEO Chemicalscites National Toxicology Program, Institute of Environmental Health Sciences, National Institutes of Health (NTP). 1992. National Toxicology Program Chemical Repository Database. Research Triangle Park, North Carolina.
146 °Cshown 146 °C [3] ILO-WHO International Chemical Safety Cards (ICSCs)
146 °C 146 °C @760 [mm Hg] [5] PAC Chemical Database, U.S. Department of Energy
Density: 1.1 g/cu cm[4]
4 values
Only one source reports it.
Value As written Source
– 1.1 at 68 °F (NTP, 1992) - Denser than water [1] CAMEO Chemicalscites National Toxicology Program, Institute of Environmental Health Sciences, National Institutes of Health (NTP). 1992. National Toxicology Program Chemical Repository Database. Research Triangle Park, North Carolina.
1.1 g/mLshown 1.1 g/cu cm [4] Hazardous Substances Data Bank (HSDB)cites Lewis, R.J. Sax's Dangerous Properties of Industrial Materials. 10th ed. Volumes 1-3 New York, NY: John Wiley & Sons Inc., 1999., p. 2972
– 1.1 g/cm³ [3] ILO-WHO International Chemical Safety Cards (ICSCs)
– 1.45 @ 113°C [5] PAC Chemical Database, U.S. Department of Energy
1 more value was reported but failed the checks (unreadable or out of range), so it is not shown.
Solubility in water: Solubility in water, g/100ml at 20 °C: 15[3]
3 values
From ILO-WHO International Chemical Safety Cards (ICSCs), the most authoritative source here.
Value As written Source
– Very soluble (NTP, 1992) [1] CAMEO Chemicalscites National Toxicology Program, Institute of Environmental Health Sciences, National Institutes of Health (NTP). 1992. National Toxicology Program Chemical Repository Database. Research Triangle Park, North Carolina.
– Readily soluble in methanol, but only slightly soluble in benzene and heptane. [4] Hazardous Substances Data Bank (HSDB)cites Eller K, Henkes E; Ullmann's Encyclopedia of Industrial Chemistry. 7th ed. (2005). NY, NY: John Wiley & Sons; Amines, Aliphatic. Online Posting Date: June 15, 2000.
–shown Solubility in water, g/100ml at 20 °C: 15 [3] ILO-WHO International Chemical Safety Cards (ICSCs)
log P: -1.17[3]
2 values
Sources disagree; from ILO-WHO International Chemical Safety Cards (ICSCs), the most authoritative.
Value As written Source
– log Kow = -1.50 [4] Hazardous Substances Data Bank (HSDB)cites Hansch, C., Leo, A., D. Hoekman. Exploring QSAR - Hydrophobic, Electronic, and Steric Constants. Washington, DC: American Chemical Society., 1995., p. 10
–shown -1.17 [3] ILO-WHO International Chemical Safety Cards (ICSCs)
pKa: pKa1 = 9.73 (first nitrogen)[4]
2 values
Only one source reports it.
Value As written Source
–shown pKa1 = 9.73 (first nitrogen) [4] Hazardous Substances Data Bank (HSDB)cites Perrin DD; Dissociation Constants of Organic Bases in Aqueous Solution. IUPAC Chemical Data Series: Supplement. Buttersworth, London (1972)
– pKa2 = 5.33 (second nitrogen) (conjugate acid) [4] Hazardous Substances Data Bank (HSDB)cites Perrin DD; Dissociation Constants of Organic Bases in Aqueous Solution. IUPAC Chemical Data Series: Supplement. Buttersworth, London (1972)
Vapor pressure: Vapor pressure, Pa at 20 °C: 21[3]
3 values
3 of 3 sources agree on it (most common value).
Value As written Source
0.16 mmHg 0.16 mm Hg at 20 °C [4] Hazardous Substances Data Bank (HSDB)cites Kirk-Othmer Encyclopedia of Chemical Technology. 3rd ed., Volumes 1-26. New York, NY: John Wiley and Sons, 1978-1984., p. V2: 296 (1978)
0.16 mmHgshown Vapor pressure, Pa at 20 °C: 21 [3] ILO-WHO International Chemical Safety Cards (ICSCs)
0.16 mmHg 0.16 [mm Hg] @20 °C [5] PAC Chemical Database, U.S. Department of Energy
1 more value was reported but failed the checks (unreadable or out of range), so it is not shown.
Flash point: 107 °C (Cleveland Open Cup)[4]
3 values
Sources disagree; from Hazardous Substances Data Bank (HSDB), the most authoritative.
Value As written Source
88 °C 190 °F (NTP, 1992) [1] CAMEO Chemicalscites National Toxicology Program, Institute of Environmental Health Sciences, National Institutes of Health (NTP). 1992. National Toxicology Program Chemical Repository Database. Research Triangle Park, North Carolina.
107 °Cshown 107 °C (Cleveland Open Cup) [4] Hazardous Substances Data Bank (HSDB)cites Kirk-Othmer Encyclopedia of Chemical Technology. 3rd ed., Volumes 1-26. New York, NY: John Wiley and Sons, 1978-1984., p. V2 296
65 °C 65 °C [3] ILO-WHO International Chemical Safety Cards (ICSCs)
Autoignition temperature: 320 °C[3]

Value	As written	Source
–	Needle-like white or colorless crystals. Shipped as a solid or suspended in a liquid medium. Very corrosive to skin, eyes and mucous membranes. Solid turns dark when exposed to light. Flash point 190 °F. Used as a corrosion inhibitor and as an insecticide.	[1] CAMEO Chemicals
–	Large Crystals; CBI; Liquid	[2] EPA Chemical Data Reporting (CDR)
–	HYGROSCOPIC COLOURLESS CRYSTALS OR WHITE FLAKES WITH PUNGENT ODOUR.	[3] ILO-WHO International Chemical Safety Cards (ICSCs)
–	WHITE TO SLIGHTLY OFF-WHITE LUMPS OR FLAKES	[4] Hazardous Substances Data Bank (HSDB)cites Osol, A. and J.E. Hoover, et al. (eds.). Remington's Pharmaceutical Sciences. 15th ed. Easton, Pennsylvania: Mack Publishing Co., 1975., p. 1175
–shown	Colorless, transparent, needle-like crystals	[4] Hazardous Substances Data Bank (HSDB)cites Lewis, R.J. Sr.; Hawley's Condensed Chemical Dictionary 14th Edition. John Wiley & Sons, Inc. New York, NY 2001., p. 881

Value	As written	Source
–shown	Typical amine odor	[4] Hazardous Substances Data Bank (HSDB)cites Eller K, Henkes E; Ullmann's Encyclopedia of Industrial Chemistry. 7th ed. (2005). NY, NY: John Wiley & Sons; Amines, Aliphatic. Online Posting Date: June 15, 2000.
–	AMMONIACAL ODOR	[4] Hazardous Substances Data Bank (HSDB)cites Osol, A. and J.E. Hoover, et al. (eds.). Remington's Pharmaceutical Sciences. 15th ed. Easton, Pennsylvania: Mack Publishing Co., 1975., p. 1075

Value	As written	Source
106 °C	223 °F (NTP, 1992)	[1] CAMEO Chemicalscites National Toxicology Program, Institute of Environmental Health Sciences, National Institutes of Health (NTP). 1992. National Toxicology Program Chemical Repository Database. Research Triangle Park, North Carolina.
106 °Cshown	106 °C	[3] ILO-WHO International Chemical Safety Cards (ICSCs)
106 °C	106 °C	[5] PAC Chemical Database, U.S. Department of Energy

Value	As written	Source
146 °C	295 °F at 760 mmHg (NTP, 1992)	[1] CAMEO Chemicalscites National Toxicology Program, Institute of Environmental Health Sciences, National Institutes of Health (NTP). 1992. National Toxicology Program Chemical Repository Database. Research Triangle Park, North Carolina.
146 °Cshown	146 °C	[3] ILO-WHO International Chemical Safety Cards (ICSCs)
146 °C	146 °C @760 [mm Hg]	[5] PAC Chemical Database, U.S. Department of Energy

Value	As written	Source
–	1.1 at 68 °F (NTP, 1992) - Denser than water	[1] CAMEO Chemicalscites National Toxicology Program, Institute of Environmental Health Sciences, National Institutes of Health (NTP). 1992. National Toxicology Program Chemical Repository Database. Research Triangle Park, North Carolina.
1.1 g/mLshown	1.1 g/cu cm	[4] Hazardous Substances Data Bank (HSDB)cites Lewis, R.J. Sax's Dangerous Properties of Industrial Materials. 10th ed. Volumes 1-3 New York, NY: John Wiley & Sons Inc., 1999., p. 2972
–	1.1 g/cm³	[3] ILO-WHO International Chemical Safety Cards (ICSCs)
–	1.45 @ 113°C	[5] PAC Chemical Database, U.S. Department of Energy

Value	As written	Source
–	Very soluble (NTP, 1992)	[1] CAMEO Chemicalscites National Toxicology Program, Institute of Environmental Health Sciences, National Institutes of Health (NTP). 1992. National Toxicology Program Chemical Repository Database. Research Triangle Park, North Carolina.
–	Readily soluble in methanol, but only slightly soluble in benzene and heptane.	[4] Hazardous Substances Data Bank (HSDB)cites Eller K, Henkes E; Ullmann's Encyclopedia of Industrial Chemistry. 7th ed. (2005). NY, NY: John Wiley & Sons; Amines, Aliphatic. Online Posting Date: June 15, 2000.
–shown	Solubility in water, g/100ml at 20 °C: 15	[3] ILO-WHO International Chemical Safety Cards (ICSCs)

Value	As written	Source
–	log Kow = -1.50	[4] Hazardous Substances Data Bank (HSDB)cites Hansch, C., Leo, A., D. Hoekman. Exploring QSAR - Hydrophobic, Electronic, and Steric Constants. Washington, DC: American Chemical Society., 1995., p. 10
–shown	-1.17	[3] ILO-WHO International Chemical Safety Cards (ICSCs)

Value	As written	Source
–shown	pKa1 = 9.73 (first nitrogen)	[4] Hazardous Substances Data Bank (HSDB)cites Perrin DD; Dissociation Constants of Organic Bases in Aqueous Solution. IUPAC Chemical Data Series: Supplement. Buttersworth, London (1972)
–	pKa2 = 5.33 (second nitrogen) (conjugate acid)	[4] Hazardous Substances Data Bank (HSDB)cites Perrin DD; Dissociation Constants of Organic Bases in Aqueous Solution. IUPAC Chemical Data Series: Supplement. Buttersworth, London (1972)

Value	As written	Source
0.16 mmHg	0.16 mm Hg at 20 °C	[4] Hazardous Substances Data Bank (HSDB)cites Kirk-Othmer Encyclopedia of Chemical Technology. 3rd ed., Volumes 1-26. New York, NY: John Wiley and Sons, 1978-1984., p. V2: 296 (1978)
0.16 mmHgshown	Vapor pressure, Pa at 20 °C: 21	[3] ILO-WHO International Chemical Safety Cards (ICSCs)
0.16 mmHg	0.16 [mm Hg] @20 °C	[5] PAC Chemical Database, U.S. Department of Energy

Value	As written	Source
88 °C	190 °F (NTP, 1992)	[1] CAMEO Chemicalscites National Toxicology Program, Institute of Environmental Health Sciences, National Institutes of Health (NTP). 1992. National Toxicology Program Chemical Repository Database. Research Triangle Park, North Carolina.
107 °Cshown	107 °C (Cleveland Open Cup)	[4] Hazardous Substances Data Bank (HSDB)cites Kirk-Othmer Encyclopedia of Chemical Technology. 3rd ed., Volumes 1-26. New York, NY: John Wiley and Sons, 1978-1984., p. V2 296
65 °C	65 °C	[3] ILO-WHO International Chemical Safety Cards (ICSCs)

Each value as its source reports it, with the source's number after it (listed under References). Where several sources report a property, the row shows the value most of them agree on, the rule the app uses; open the values to see every one.

Calculated

Heavy atoms: 6
Rings: 1
Aromatic rings: 0
Fraction sp³ carbons (Fsp3): 1
H-bond donors: 2
H-bond acceptors: 2
Rotatable bonds: 0
TPSA (Å²): 24.1
Formal charge: 0
XLogP3: -1.5 PubChem
Complexity: 26 PubChem
Stereocenters: None
Double-bond geometry: None specified
Point group: Cs of one 3D conformer with its hydrogens, by Athanor’s engine (as in the app)

Elemental analysis

C55.78%
H11.70%
N32.52%

Isotope pattern

Each peak is a nominal mass with its abundance-weighted exact mass, as a percentage of the tallest, from IUPAC natural isotope abundances.

Computed from the structure with RDKit 2026.09 when this page was built, beside PubChem's own computed values from its record; where the two differ, both are shown.

Predicted

log P: -0.82 Crippen (Wildman and Crippen 1999)
log S (water solubility): 0.14 ESOL (Delaney 2004), log mol/L
Synthetic accessibility: 2.7 SA score, 1 easy to 10 hard (Ertl and Schuffenhauer 2009)

Drug-likeness: Lipinski’s rule of five

Molecular weight ≤ 500: 86.14
log P ≤ 5 (Crippen): -0.82
H-bond donors ≤ 5: 2
H-bond acceptors ≤ 10: 2

Passes all four rules.

¹³C NMR shifts, predicted

Predictions, not measurements; each names its method. A measured log P, where a source reports one, is under Physical properties.

Safety

Danger

Harmonized EU classification (CLP Annex VI). Source [6].

Corrosive
Health hazard

NFPA 704[4]

H314Causes severe skin burns and eye damage
H317May cause an allergic skin reaction
H334May cause allergy or asthma symptoms or breathing difficulties if inhaled
H361fdSuspected of damaging fertility; Suspected of damaging the unborn child

Precautionary statements: P203, P233, P260, P261, P264, P271, P272, P280, P284, P301+P330+P331, P302+P352, P302+P361+P354, P304+P340, P305+P354+P338, P316, P318, P321, P333+P317, P342+P316, P362+P364, P363, P403, P405, P501

View all classifications (4)

[6] Regulation (EC) No 1272/2008 of the European Parliament and of the Council · DangerH314, H317, H334, H361fd
[6] Regulation (EC) No 1272/2008 of the European Parliament and of the Council · DangerH314, H317, H334, H361fd
[7] European Chemicals Agency (ECHA)This chemical does not meet GHS hazard criteria for 0.1% (1 of 768) of reports.
[7] European Chemicals Agency (ECHA) · 768 reports · DangerH228, H314, H317, H318, H334, H361, H361fd

Exposure limits

TLV: 0.03 ppm as TWA; (SEN); A4 (not classifiable as a human carcinogen).[3]
EU-OEL: 0.1 mg/m[3]
MAK (Maximale Arbeitsplatz Konzentration): Sensitization of respiratory tract and skin (SAH).[3]

First aid

Eyes: First check the victim for contact lenses and remove if present. Flush victim's eyes with water or normal saline solution for 20 to 30 minutes while simultaneously calling a hospital or poison control center. Do not put any ointments, oils, or medication in the victim's eyes without specific instructions from a physician. Immediately transport the victim after flushing eyes to a hospital even if no symptoms (such as redness or irritation) develop. Skin: Immediately flood affected skin with water while removing and isolating all contaminated clothing.[1]
General First Aid: · Call 911 or emergency medical service. · Ensure that medical personnel are aware of the material(s) involved, take precautions to protect themselves and avoid contamination. · Move victim to fresh air if it can be done safely. · Administer oxygen if breathing is difficult. · If victim is not breathing: -- DO NOT perform mouth-to-mouth resuscitation; the victim may have ingested or inhaled the substance. -- If equipped and pulse detected, wash face and mouth, then give artificial respiration using a proper respiratory medical device (bag-valve mask, pocket mask equipped…[8]
Fresh air, rest. Half-upright position. Artificial respiration may be needed. Refer for medical attention.[3]
Remove contaminated clothes. Rinse skin with plenty of water or shower for at least 15 minutes. Refer for medical attention .[3]

Storage

Separated from strong acids, strong oxidants, acid anhydrides, metals and food and feedstuffs. Dry. Well closed.[3]
Piperazine must be stored to avoid contact with oxidizers (such as perchlorates, peroxides, permanganates, chlorates, and nitrates) since violent reactions occur. . Sources of ignition such as smoking and open flames are prohibited where piperazine is used, handled, or stored in a manner that could create a potential fire or explosion hazard. Store in tightly closed containers in a cool, well vented area away form oxidizers. Where possible, automatically transfer material from drums or other storage containers to process containers.[4]
Store below 40 °C (104 °F), preferably between 15 and 30 °C (59 and 86 °F), in a well-closed container, unless otherwise specified by manufacturer. (piperazine adipate granules for oral solution)[4]
Store below 40 °C (104 °F), preferably between 15 and 30 °C (59 and 86 °F), in a well-closed container, unless otherwise specified by manufacturer. Protect from freezing. (piperazine adipate oral suspension)[4]

Incompatibilities

Violent reaction with strong oxidizers and dicyanofurazan. Incompatible with nitrogen compounds, carbon tetrachloride. Attacks aluminum, copper, nickel, magnesium, and zinc.[4]

Safety data sheets on the supplier’s page: Enamine, Angene Chemical, RR Scientific.

Always read the supplier’s safety data sheet before working with it.

Spectra

Experimental spectra held by these sources; each link opens the source's own record.

Literature

Reading PubChem, OpenAlex and GSRS…

Bioactivity

Reading ChEMBL…

References

[1]CAMEO Chemicals · Public domain (NOAA) · via PubChem · retrieved 2026-10-14
[2]EPA Chemical Data Reporting (CDR) · Public domain (US EPA) · via PubChem · retrieved 2026-10-14
[3]ILO-WHO International Chemical Safety Cards (ICSCs) · CC BY 4.0 · via PubChem · retrieved 2026-10-14
[4]Hazardous Substances Data Bank (HSDB) · Public domain (US NLM) · via PubChem · retrieved 2026-10-14
[5]PAC Chemical Database, U.S. Department of Energy · Public domain (US DOE) · via PubChem · retrieved 2026-10-14
[6]Regulation (EC) No 1272/2008 of the European Parliament and of the Council · EU reuse policy, CC BY 4.0 · via PubChem · retrieved 2026-10-14
[7]European Chemicals Agency (ECHA) · ECHA legal notice: reuse with acknowledgement · via PubChem · retrieved 2026-10-14
[8]Emergency Response Guidebook (ERG) · Public domain (US DOT) · via PubChem · retrieved 2026-10-14
[9]NMRShiftDB · Linked only · via PubChem · retrieved 2026-10-14
[10]SpectraBase · Linked only · via PubChem · retrieved 2026-10-14
[11]NIST Mass Spectrometry Data Center · Linked only · via PubChem · retrieved 2026-10-14
[12]Human Metabolome Database (HMDB) · Linked only · via PubChem · retrieved 2026-10-14
[13]MassBank Europe · Linked only · via PubChem · retrieved 2026-10-14
[14]MassBank of North America (MoNA) · CC BY 4.0 · via PubChem · retrieved 2026-10-14
·Calculated values: computed by Athanor with RDKit 2026.09 from the structure.
·Literature on PubChem

Data last updated 2026-10-14.