Isobutanol

CAS 78-83-1

Listed as a flavouring agent by the US.

Listed as flavouring agents and adjuvants (US)
Chemical structure of Isobutanol, from PubChem compound 6560
Structure from PubChem CID 6560 (National Library of Medicine, public domain). A depiction of one compound: where a listing covers a family, or a substance has no single structure, this page shows none.

Isobutanol, or 2-methylpropan-1-ol, is used as an extraction solvent and as a flavouring agent.

Where it is and isn’t permitted

Status of Isobutanol by jurisdiction. Every jurisdiction this site covers is listed, including those where the substance does not appear.
JurisdictionStatusScope and limitsCitation
Australia and New ZealandFood Standards Australia New ZealandNo listed food uses foundThis site has not matched this substance to any food use on this jurisdiction’s list of authorised food additives. A food additive may be used only in foods that list names. Flavourings, enzymes, processing aids and added nutrients are regulated separately and do not appear on it.
CanadaHealth CanadaNo listing matchedHealth Canada’s lists name additives without E or INS numbers, so this site matches them by exact name. A substance listed there under a name this site does not recognise has no row here.
European UnionEuropean Commission / EFSANo listed food uses foundThis site has not matched this substance to any food use on this jurisdiction’s list of authorised food additives. A food additive may be used only in foods that list names. Flavourings, enzymes, processing aids and added nutrients are regulated separately and do not appear on it.
Great BritainFood Standards Agency / Food Standards ScotlandNo listed food uses foundThis site has not matched this substance to any food use on this jurisdiction’s list of authorised food additives. A food additive may be used only in foods that list names. Flavourings, enzymes, processing aids and added nutrients are regulated separately and do not appear on it.
JapanConsumer Affairs AgencyPermitted, with conditions
Designated additive: Appended Table 1, item 57, イソブタノール (“Isobutanol” in the unofficial English translation). …

Designated additive: Appended Table 1, item 57, イソブタノール (“Isobutanol” in the unofficial English translation). Standards for use — Specifications and Standards for Foods, Food Additives, etc. (MHW Notification No. 370 of 1959), Part II (Food Additives), F (Standards for use), entry イソブタノール: (1) [may be used only for the purpose of flavouring] “イソブタノールは、着香の目的以外に使用してはならない。” The Japanese is the standard as published. There is no official English translation of the Notification; the English in square brackets is this site’s description of what each sentence does, not a translation of the foods or the levels. Compositional specifications for this additive, in the same Notification, are not imported and are not shown here; nor are the general rules in F 添加物一般, which apply to every additive.

Regulations for Enforcement of the Food Sanitation Act (MHW Ordinance No. 23 of 1948), Appended Table 1retrieved 2026-10-18
South KoreaMinistry of Food and Drug SafetyNo listing matchedThis site imports Part III of South Korea’s Standards and Specifications for Food Additives, matched by CAS number, then INS number, then exact name. Mixed preparations and sanitisers are not imported, and an entry whose identifiers disagreed with a page’s is held for review, so an empty row does not show that South Korea does not permit the substance.
United StatesFood and Drug AdministrationPermitted, with conditions

Named in the list of synthetic flavoring substances and adjuvants in 21 CFR 172.515(b), which may be safely used in food in the minimum quantity required to produce their intended effect. The section is held on this site as the page synthetic-flavoring-substances-and-adjuvants; read it for the conditions.

21 CFR 172.515retrieved 2026-10-18
Codex AlimentariusCodex Alimentarius Commission / JECFANot listedDoes not appear on this jurisdiction’s permitted list. That is not the same as being prohibited.

How much is permitted

A listing usually limits the quantity as well as the food. Only one of the forms that takes is a figure: quantum satis and good manufacturing practice permit the amount the technological effect requires and no more, which is a limit rather than the absence of one. Figures below are the range across every food category this page is listed in, and categories differ between regulators — see how much is permitted.

Japan—1 no quantity stated
United States—1 no quantity stated

No regulator sets a figure for Isobutanol. That is not an absence of control: where the listing says quantum satis or good manufacturing practice, the quantity is limited to what the effect requires.

What it is made from

Made industrially from propylene, and also formed during alcoholic fermentation as a fusel alcohol.

  • Vegan
  • Vegetarian

Compare other additives on the dietary indexes.

CAS registry number
78-83-1
InChIKey
ZXEKIIBDNHEJCQ-UHFFFAOYSA-N
PubChem
CID 6560

How JECFA defines it

The international specification for identity and purity, prepared by the Joint FAO/WHO Expert Committee on Food Additives and published by FAO. It is a different document from any above, written by a different body and revised on its own cycle; it is advisory, and a country adopts it or does not.

Isobutanol

Synonyms: Isobutyl alcohol, IBA, isopropyl carbinol IBA; Isobutyl alcohol; Isopropyl carbinol

Assay, identification and purity criteria

Description and assay

Specification history
Prepared at the 51st JECFA (1998), published in FNP 52 Add 6 (1998) superseding earlier specifications prepared by the 28th JECFA (1984), published in FNP 31/2 (1984) and republished in FNP 52 (1992). Metals and arsenic specifications revised at the 63rd JECFA (2004) No ADI allocated at the 23rd JECFA in 1979.
Chemical names
2-Methyl-1-propanol, 2-methylpropan-1-ol
C.A.S. number
78-83-1
Chemical formula
C 4 H 10 O
Structural formula
(CH 3 ) 2 CHCH 2 OH
Formula weight
74.12
Assay
Not less than 99% of C 4 H 10 O
DESCRIPTION
Clear, colourless, flammable liquid with a characteristic odour
FUNCTIONAL USES
Extraction solvent, flavouring agent (see "Flavouring agents" monograph JECFA no. 251)
METHOD OF ASSAY
Determine by gas-liquid chromatography (see Volume 4), using the following conditions: Column - length: 2.4 m - diameter: 6 mm - material: copper - packing: 23% Carbowax 1500 - support: Chromosorb W (60/80 mesh) Carrier gas: Helium Flow rate: 150 ml/min Detector type: FID Temperatures - injection port: 150 o - column: 70 o - detector: 150 o Inject 1 to 5 μl of sample, obtain chromatogram and determine content of each constituent by the method of area normalization.

Identification

Solubility (Vol. 4)
Soluble in water; miscible with ethanol and ether
Specific gravity (Vol. 4)
d 20 : 0.802 - 0.804 d 25 : 0.779 - 0.801
Infrared absorption
The infrared spectrum of the sample corresponds with the reference infrared spectrum below

Purity criteria

Water (Vol. 4)
Not more than 0.2% (Karl Fischer Method)
Distillation range (Vol. 4)
106 - 109 o
Colour (Vol. 4)
Not more than Colour Standard No. 10
Non-volatile residue (Vol. 4)
Not more than 1 mg/100 ml
Acidity
Not more than 0.003% (as acetic acid) To 60 g of the sample add a few drops of phenolphthalein TS and titrate with 0.1 N ethanolic potassium hydroxide to a pink end-point which persists for at least 15 sec. Not more than 0.3 ml is required.
Aldehydes and ketones
Not more than 0.2% (as butanal) Proceed as directed under method Aldehyde and Ketone Determination , using 10 g of the sample and 36.06 as the equivalent factor (e) in the calculation.
Lead (Vol. 4)
Not more than 2 mg/kg Determine using an atomic absorption technique appropriate to the specified level. The selection of sample size and method of sample preparation may be based on the principles of the method described in Volume 4, “Instrumental Methods.”
Infrared spectrum
Isobutanol (Reprinted from Merck FT-IR Atlas through courtesy of Dr K.G.R. Pachler, Mr F. Matlock, and Dr H-U. Gremlich and VCH Verlagsgesellschaft, Weinheim, Germany.)

FAO JECFA Monograph 1 (2006)

Every name it appears under

61 recorded names. A label may use any of them.

CAS registry number

  • 78-83-1

Other names

  • 1-Hydroxymethylpropane
  • 1-Propanol, 2-methyl-
  • 2-?Methyl-?1-?propanol(Isobutyl Alcohol)
  • 2-Methyl propanol
  • 2-Methyl-1-propanol
  • 2-Methyl-1-propanol, 99%
  • 2-Methyl-1-propanol, 99.5%
  • 2-Methyl-1-propanol, AR, 99%
  • 2-methyl-1-propanyl alcohol
  • 2-methyl-l-propanol
  • 2-methyl-n-propanol
  • 2-methyl-propan-1-ol
  • 2-methyl-propanol
  • 2-Methylpropan-1-ol
  • 2-methylpropanoI
  • 2-Methylpropanol
  • 2-Methylpropanol-1
  • 2-Methylpropyl alcohol
  • 4-01-00-01588 (Beilstein Handbook Reference)
  • 56F9Z98TEM
  • 78-83-1(Ethanol)
  • Alcool isobutylique
  • BRN 1730878
  • Butanol-iso
  • CCRIS 2300
  • FEMA No. 2179
  • FEMA Number 2179
  • Fermentation butyl alcohol
  • HSDB 49
  • i-BuOH
  • i-Butanol
  • i-Butyl alcohol
  • IBA
  • iBuOH
  • iso butanol
  • iso-BuOH
  • iso-butanol
  • Iso-butyl alcohol
  • iso-C4H9OH
  • Isobutanol
  • Isobutanol (IBA)
  • Isobutanol ACS grade
  • Isobutanol in Ethanol
  • Isobutanol or isobutyl alcohol
  • Isobutanol, HPLC Grade
  • Isobutanol, Spectrophotometric Grade
  • isobutonol
  • Isobutyl alcohol
  • ISOBUTYL ALCOHOL (ISOBUTANOL)
  • Isobutyl alcohol (natural)
  • isobutylalcohol
  • Isobutylalkohol
  • Isopropyl carbinol
  • Isopropyl carbitol
  • Isopropylcarbinol
  • Methyl-2 propanol-1
  • Propanol, 2-methyl-
  • RCRA waste no. U140
  • RCRA waste number U140
  • WLN: Q1Y1&1

Hazard reference values

No reference value for this substance in the sources we hold.

Evidence and how bodies read it

Studies, and the differing conclusions regulators drew from them, are curated rather than machine-read, and none has been written for this substance yet.

Common questions

Assembled from what is above, in the words the questions are usually asked in. Each answer is the same statement the relevant section makes, with the same citations behind it.

What is Isobutanol?
Isobutanol, or 2-methylpropan-1-ol, is used as an extraction solvent and as a flavouring agent.
What is Isobutanol used for in food?
It is listed as a flavouring agent — the role the US assigns it. This page shows every function each regulator records, with the citation for each.
Is Isobutanol banned in Europe?
No. Isobutanol is not on the EU's list of authorised food additives, but it would not be expected to be: every role regulators give it — flavouring agent — the EU regulates under separate law. Its absence from the additives list says nothing about whether it is permitted in Europe.
Where is Isobutanol permitted?
Of the seven regulators this site reads, Japan and the US permit it. Each permission is for named foods at named levels, not a blanket one; the table on this page gives them with citations.
Is Isobutanol vegan?
Yes. Isobutanol is not derived from animals, and is suitable for vegetarians. This page says what it is made from and how.

Sources for this page

  • jp retrieved 2026-10-18
  • us-listings retrieved 2026-10-18
  • jecfaspecs retrieved 2026-09-23

Full licence terms and publisher details on Sources. How this page is built and updated: Method.

Machine-readable: a JSON record of this additive is given on request —how to ask for access.

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