Butyl nitrites
HMT 15 June 2026Butyl nitrites
In organic chemistry, butyl is a four-carbon alkyl radical or substituent group with general chemical formula −C4H9, derived from either of the two isomers (n-butane and isobutane) of butane. The isomer n-butane can connect in two ways, giving rise to two "-butyl" groups: If it connects at one of the two terminal carbon atoms, it is normal butyl or n-butyl: −CH2−CH2−CH2−CH3 (preferred IUPAC name: butyl) If it connects at one of the non-terminal (internal) carbon atoms, it is secondary butyl or sec-butyl: −CH(CH3)−CH2−CH3 (preferred IUPAC name: butan-2-yl) The second isomer of butane, isobutane, can also connect in two ways, giving rise to two additional groups: If it connects at one of the three terminal carbons, it is isobutyl: −CH2−CH(CH3)2 (preferred IUPAC name: 2-methylpropyl) If it connects at the central carbon, it is tertiary butyl, tert-butyl or t-butyl: −C(CH3)3 (preferred IUPAC name: tert-butyl) Wikipedia
| Emergency Response Guide No. 129 |
Hazardous Materials Table
Source: 49 CFR §172 (15 June 2026)(3) Hazard Class3Flammable liquids |
(4) Identification number |
(5) Packing Group |
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(6) Labels |
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(7) Special Provisions (§172.102)
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| T11 | |
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| TP1 | |
| TP8 | |
| TP27 |
(8) Packing Authorizations (§173.***) 
| (8A) Exceptions | 150 | see 49 CFR §173.150 |
|---|---|---|
| (8B) Non-bulk | 201 | see 49 CFR §173.201 |
| (8C) Bulk | 243 | see 49 CFR §173.243 |
(9) Quantity Limits 
| (9A) Passenger aircraft/rail | 1 L |
|---|---|
| (9B) Cargo aircraft only | 30 L |
(10) Vessel stowage 
| (10A) Location | |
|---|---|
| (10B) Other |
(3) Hazard Class3Flammable liquids |
(4) Identification number |
(5) Packing Group |
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(6) Labels |
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(7) Special Provisions (§172.102)
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| IB2 | |
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| T4 | |
| TP1 |
(8) Packing Authorizations (§173.***) 
| (8A) Exceptions | 150 | see 49 CFR §173.150 |
|---|---|---|
| (8B) Non-bulk | 202 | see 49 CFR §173.202 |
| (8C) Bulk | 242 | see 49 CFR §173.242 |
(9) Quantity Limits 
| (9A) Passenger aircraft/rail | 5 L |
|---|---|
| (9B) Cargo aircraft only | 60 L |
(10) Vessel stowage 
| (10A) Location | |
|---|---|
| (10B) Other |
(3) Hazard Class3Flammable liquids |
(4) Identification number |
(5) Packing Group |
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(6) Labels |
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(7) Special Provisions (§172.102)
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| B1 | |
|---|---|
| IB3 | |
| T2 | |
| TP1 |
(8) Packing Authorizations (§173.***) 
| (8A) Exceptions | 150 | see 49 CFR §173.150 |
|---|---|---|
| (8B) Non-bulk | 203 | see 49 CFR §173.203 |
| (8C) Bulk | 242 | see 49 CFR §173.242 |
(9) Quantity Limits 
| (9A) Passenger aircraft/rail | 60 L |
|---|---|
| (9B) Cargo aircraft only | 220 L |
(10) Vessel stowage 
| (10A) Location | |
|---|---|
| (10B) Other |
Packing group comparison
Multiple packing groups apply to this entry. See assignment criteria in 49 CFR §173 Subpart D. Details are in the tabs above; differences are highlighted.
Segregation chart for load, transport, and storage
This chart shows whether loading, transport, or storage with other hazard classes is permitted, prohibited, or restricted. Based on 49 CFR §177.848.
| Hazard class | 8![]() | 7![]() | 6.1![]() | 5.2![]() | 5.1![]() | 4.3![]() | 4.2![]() | 4.1![]() | 3![]() | 2.3B![]() | 2.3A![]() | 2.2![]() | 2.1![]() | 1.6![]() | 1.5![]() | 1.4![]() | 1.3![]() | 1.1/1.2![]() |
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8 ![]() |
| Must not be loaded, transported, or stored together in the same vehicle or facility. | |
| May be loaded, transported, or stored together. | |
| May be loaded, transported, or stored together only with restrictions. |
Similar substances
| UN / ID | Proper shipping name | Hazard class |
|---|---|---|
| UN 3219 | Nitrites, inorganic, aqueous solution, n.o.s | 5.1 |
| UN 2627 | Nitrites, inorganic, n.o.s. | 5.1 |
