Isobutyric Acid

Product Name:

Isobutyric acid

CAS:

79-31-2

MF:

C4H8O2

MW:

88.11

EINECS:

201-195-7

Mol File:

79-31-2.mol

Melting point 

-47 °C

Boiling point 

153-154 °C(lit.)

density 

0.95 g/mL at 25 °C(lit.)

vapor density 

3.04 (vs air)

vapor pressure 

1.5 mm Hg ( 20 °C)

refractive index 

n20/D 1.393(lit.)

FEMA 

2222 | ISOBUTYRIC ACID

Fp 

132 °F

storage temp. 

room temp

solubility 

618g/l

pka

4.84(at 20℃)

form 

Liquid

color 

Clear colorless

PH

2.3 (500g/l, H2O, 25℃)

Odor Threshold

0.0015ppm

explosive limit

1.6-7.3%(V)

Water Solubility 

210 g/L (20 ºC)

JECFA Number

253

Merck 

14,5155

BRN 

635770

InChIKey

KQNPFQTWMSNSAP-UHFFFAOYSA-N

CAS DataBase Reference

79-31-2(CAS DataBase Reference)

NIST Chemistry Reference

Propanoic acid, 2-methyl-(79-31-2)

EPA Substance Registry System

Isobutyric acid (79-31-2)

Hazard Codes 

Xn

Risk Statements 

21/22

Safety Statements 

23-36/37/39-24/25

RIDADR 

UN 2529 3/PG 3

WGK Germany 

1

RTECS 

NQ4375000

F 

13

Autoignition Temperature

824 °F

TSCA 

Yes

HazardClass 

3

PackingGroup 

III

HS Code 

29156000

Hazardous Substances Data

79-31-2(Hazardous Substances Data)

Toxicity

LD50 orally in Rabbit: 266 mg/kg LD50 dermal Rabbit 475 mg/kg

Chemical properties

Colorless oily liquid; strong irritating odor; miscible with water; soluble in alcohol, ether and so on.

Content analysis

Determined by the same content analysis method of "butyric acid (03454)".

Toxicity

GRAS (FEMA).
LD50 280 mg/kg (rat, oral).

Use limits

FEMA (mg/kg): soft drinks 4.1; cold drinks 12; candy 41; baked food 38; gummy candy 470; margarine 30.
Moderate use as limits (FDA § 172.515, 2000).

Production method

The preparation of isobutyric acid is similar with butyric acid, which is performed by the direct oxidation of isobutyl alcohol and isobutyraldehyde. Isobutyric acid can be directly generated from the oxidation of isobutyraldehyde in air or oxygen. Other manufacturing methods have isobutyronitrile hydrolysis and methacrylic acid hydrogenation. The oxidation of 2-methyl-1-nitropropane to prepare isobutyric acid can also obtain a higher yield. The purification of Isobutyric acid can be realized by azeotropic distillation with water, and anhydrous isobutyric acid can be obtained by the extractive distillation from carbon tetrachloride. Propylene and formic acid ester can react at 50 °C with the catalysis of hydrofluoric acid to generate methyl isobutyrate and propyl isobutyrate.
Application: Isobutyric acid is not more important than butyric acid, but has the similar uses with n-butyric acid. Isobutyric acid is mainly used to produce the corresponding esters, such as methyl isobutyrate with apricot incense, propyl isobutyrate with pineapple flavor, isobutyl isobutyrate with banana flavor, octyl isobutyrate with grapes taste, benzyl isobutyrate with jasmine smell, etc. It can be used for preparing flavors and solvents and also used in the manufacture of varnishes and plasticizers. Isobutyric acid has some important derivatives that, in the industry, is actually used for the production of isobutyronitrile intermediates, and then converted to isobutylamidine hydrochloride that is the raw materials of pesticide diazinon.

Hazards & Safety Information

Production method :Isobutyric acid can be derived from the oxidation of isobutanol.
Category : Flammable liquids
Toxicity classification : high toxicity
Acute Toxicity : Oral-Rat LD50: 280 mg/kg
Flammability hazard characteristics :Combust when meeting fire, high temperature and strong oxidant; Release irritating smoke when combusting.
Storage and transport characteristics  :Complete packaging; light loading and unloading; warehouse ventilation; away from the fire and high temperature; stored separately with oxidants and alkali. 
Fire extinguishing agent : foam, dry powder, carbon dioxide, sand

Description

Isobutyric acid has an odor and flavor similar to n-butyric acid. Prepared via oxidation of isobutyl alcohol.

Chemical Properties

Isobutyric acid has strong penetrating odor of rancid butter. The odor and flavor are similar to n-butyric acid.

Chemical Properties

clear colorless liquid

Uses

Isobutyric Acid is a flavoring agent that is a colorless liquid with a strong, penetrating odor, resembling butter. it is miscible in alcohol, propylene glycol, glycerin, mineral oil, and most fixed oils and sol- uble in water. it is obtained by chemical synthesis. it is also termed isopropylformic acid.

Uses

Manufacture of esters for solvents, flavors and perfume bases, disinfecting agent, varnish, deliming hides, tanning agent.

Definition

ChEBI: A branched fatty acid comprising propanoic acid carrying a methyl branch at C-2.

Preparation

By oxidation of isobutyl alcohol.

Aroma threshold values

Detection: 10 ppb to 9.5 ppm; aroma characteristics at 10 ppm: acidic pungent, dairy buttery and cheesy with fruity undertones.

Taste threshold values

Taste characteristics at 15 ppm: acidic, sour dairy, creamy, cheese, cultured dairy nuance.

General Description

A colorless liquid with a light odor of rancid butter. Flash point 132°F. Density 7.9 lb / gal. Corrosive to metals and tissue.

Air & Water Reactions

Flammable. Water soluble

Reactivity Profile

Isobutyric acid corrodes aluminum and other metals. Flammable hydrogen gas may accumulate in enclosed spaces in which this reaction has taken place [USCG, 1999].

Hazard

Toxic by ingestion, strong irritant to tissue.

Health Hazard

Inhalation causes irritation of nose and throat. Ingestion causes irritation of mouth and stomach. Contact with eyes or skin causes irritation.

Fire Hazard

Flammable/combustible material. May be ignited by heat, sparks or flames. Vapors may form explosive mixtures with air. Vapors may travel to source of ignition and flash back. Most vapors are heavier than air. They will spread along ground and collect in low or confined areas (sewers, basements, tanks). Vapor explosion hazard indoors, outdoors or in sewers. Runoff to sewer may create fire or explosion hazard. Containers may explode when heated. Many liquids are lighter than water.

Purification Methods

Distil the acid from KMnO4, then redistil it from P2O5. [Beilstein 2 H 288, 2 I 126, 2 II 257, 2 III 637, 2 IV 843.]

Preparation Products

Permethrin-->Gemfibrozil-->Captopril-->Isobutyryl chloride-->Isobutyric anhydride-->Ethofenprox-->ethyl 3,3-dimethylpent-4-en-1-oate-->4-(3-ISOPROPYL-1,2,4-OXADIAZOL-5-YL)PIPERIDINE-->Methyl isobutyrate-->tert-Butyl peroxypivalate-->ethyl 4,6,6-trichloro-3,3-dimethyl-hex-5-enoate-->Isobutyramide-->Benzyl isobutyrate-->Isobutyl formate-->2-(4-Ethoxyphenyl)-2-methylpropanol-->Ethyl isobutyrate-->CITRONELLYL ISOBUTYRATE-->2-Bromo-2-methylpropionyl bromide-->Ethyl 2-(2-aminothiazole-4-yl)-2-(1-tert-butoxycarbonyl-1-methylethoxyimino)acetate-->Phenoxyethyl isobutyrate-->Butyl isobutyrate-->P-TOLYL ISOBUTYRATE-->Phenethyl isobutyrate-->OCTYL ISOBUTYRATE-->HEPTYL ISOBUTYRATE-->CINNAMYL ISOBUTYRATE-->Ethyl 2-bromoisobutyrate-->Hexyl isobutyrate

Raw materials

Carbon tetrachloride-->Hydrazinium hydroxide-->Hydrofluoric acid-->2-Methyl-1-propanol-->(3R,4S)-1-Benzoyl-3-(1-methoxy-1-methylethoxy)-4-phenyl-2-azetidinone-->Methacrylic acid-->Isobutyraldehyde-->(-)-MENTHYL CHLOROFORMATE-->Isobutyronitrile-->Diazinon-->Propyl gallate-->1-Nitropropane-->BUTYRAMIDINE-->Methyl isobutyrate-->AROMA-->Isopentyl isobutyrate-->Benzyl isobutyrate-->OCTYL ISOBUTYRATE