HazMat Tool — substance information

Isobutyl formate

HMT May 2026

UN / ID: UN 2393
Hazard class: 3
Packing group: II
ERG guide: ERG 129
Special provisions: SP IB2, SP T4, SP TP1
Source: 49 CFR §172 (2026/05)

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Isobutyl formate

Isobutyl formate (2-methylpropyl methanoate) is an organic ester with the chemical formula C5H10O2. It is formed by the Fischer esterification of isobutanol with formic acid, with the aid of an acid catalyst. It is used as a flavor and fragrance ingredient because of its odor which is sweet, ethereal, and slightly fruity. Wikipedia

Emergency Response Guide No. 129

Hazardous Materials Table

Source: 49 CFR §172 (2026/05)

(3) Hazard Class

3
Flammable liquids

(4) Identification number

UN 2393

(5) Packing Group

(6) Labels

(7) Special Provisions (§172.102)

×Note:
Special provisions may be very complex. The extracts are taken from 49 CFR §172.102. Please be careful with the information, as necessary, additional conditions may be applied that are not written here. Please check the original source and report bugs.

IB2

Authorized IBCs: Metal (31A, 31B and 31N); Rigid plastics (31H1 and 31H2); Composite (31HZ1).
Additional Requirement: Only liquids with a vapor pressure less than or equal to 110 kPa at 50 °C (1.1 bar at 122 °F), or 130 kPa at 55 °C (1.3 bar at 131 °F) are authorized.

Browse special provision IB2

Minimum test pressure (bar)	2.65
Minimum shell thickness	§ 178.274(d)(2)
Pressure-relief requirements	Normal
Bottom opening requirements	§ 178.275(d)(3)

Browse special provision T4

TP1

The maximum degree of filling must not exceed the degree of filling determined by the following:
TP1

Where:
t_r is the maximum mean bulk temperature during transport, and t_f is the temperature in degrees celsius of the liquid during filling.

Browse special provision 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	B Stowage category “B” means (i) The material may be stowed “on deck” or “under deck” on a cargo vessel and on a passenger vessel carrying a number of passengers limited to not more than the larger of 25 passengers, or one passenger per each 3 m of overall vessel length; and (ii) “On deck only” on passenger vessels in which the number of passengers specified in paragraph (k)(2)(i) of this section is exceeded. Source: 49 CFR §172.101(k)
(10B) Other	n/a

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
1.1/1.2
1.3
1.4
1.5
1.6
2.1
2.2
2.3A
2.3B
3
4.1
4.2
4.3
5.1
5.2
6.1
7
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
	Methyl isobutyl ketone peroxide, in solution with more than 9 percent by mass active oxygen	Forbidden
UN 2050	Diisobutylene, isomeric compounds	3
UN 1212	Isobutanol or Isobutyl alcohol	3
UN 2045	Isobutyraldehyde or Isobutyl aldehyde	3
UN 1304	Vinyl isobutyl ether, stabilized	3
UN 1157	Diisobutyl ketone	3
UN 2527	Isobutyl acrylate, stabilized	3
UN 2283	Isobutyl methacrylate, stabilized	3
UN 2053	Methyl isobutyl carbinol	3
UN 1245	Methyl isobutyl ketone	3
UN 2361	Diisobutylamine	3
UN 1213	Isobutyl acetate	3
UN 2528	Isobutyl isobutyrate	3
UN 2486	Isobutyl isocyanate	6.1
UN 2394	Isobutyl propionate	3