2-Ethyl-3-methylpyrazine Chemical Properties

Boiling point:

57 °C10 mm Hg(lit.)

Density 

0.987 g/mL at 25 °C

vapor pressure 

1.74hPa at 20℃

FEMA 

3155 | 2-ETHYL-3-METHYLPYRAZINE

refractive index 

n20/D 1.503(lit.)

Flash point:

138 °F

storage temp. 

Sealed in dry,Room Temperature

solubility 

sparingly soluble

pka

1.94±0.10(Predicted)

Specific Gravity

0.987

color 

Colorless to Light yellow

Odor

at 0.10 % in dipropylene glycol. nutty peanut musty corn raw earthy bread

Odor Type

nutty

biological source

synthetic

Water Solubility 

sparingly soluble

JECFA Number

768

BRN 

956775

LogP

1.42 at 25℃

CAS DataBase Reference

15707-23-0(CAS DataBase Reference)

NIST Chemistry Reference

Pyrazine, 2-ethyl-3-methyl-(15707-23-0)

EPA Substance Registry System

Pyrazine, 2-ethyl-3-methyl- (15707-23-0)

Safety Information

Hazard Codes 

Xn,Xi

Risk Statements 

22-36/37/38

Safety Statements 

26-24/25

RIDADR 

UN 1993 3/PG 3

WGK Germany 

3

RTECS 

UQ3335000

Hazard Note 

Irritant

TSCA 

Yes

HazardClass 

3

PackingGroup 

III

HS Code 

29339900

MSDS

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2-Ethyl-3-methylpyrazine Usage And Synthesis

Chemical Properties

clear colorless to slightly yellow liquid

Chemical Properties

2-Ethyl-3-methylpyrazine has a strong, raw-potato, roasted, earthy odor.

Occurrence

Reported found in bakery products, roasted barley, coffee, peanuts, filberts, potato products, soy products, roasted and fried chicken, beef, pork, beer, rum, cocoa, coffee, tea, malt, shrimp and crayfish.

Uses

2-Ethyl-3-methylpyrazine is used in preparation of Chinese chestnut pyrolyzate and their application to e-cigarette.

Uses

Food additive.

Definition

ChEBI: 2-Ethyl-3-methylpyrazine, 9CI is a member of pyrazines.

Preparation

By condensation of ethylenediamine with 2,3-pentanedione.

Aroma threshold values

Detection: 2 ppm (130 ppb in water)

Taste threshold values

Taste characteristics at 10 ppm: nutty, peanut, musty corn-like with raw and oily nuances.

Hazard

Moderately toxic by ingestion.

Flammability and Explosibility

Not classified

Safety Profile

Moderately toxic by ingestion. When heated to decomposition it emits acrid smoke and irritating fumes.

Synthesis

2,3-Pentanedione, ethylenediamine and anhydrous ethanol were mixed in a three-necked flask at -5 to 3°C in a mass ratio of 1:1.1:70 and the reaction was stirred for 7 hours. After completion of the reaction, the system was slowly warmed to room temperature and stirring was continued for 3 hours. Subsequently, the temperature was raised to 65-70°C and refluxed for 4 hours. After the reaction mixture was cooled to 30-40 °C, xylene and potassium hydroxide catalyst was added to a three-necked flask, where the mass ratio of 2,3-pentanedione, potassium hydroxide to xylene was 1:0.8:2.8. Heating was continued to 65-70 °C and refluxed for 5 h. The reaction mixture was then cooled to room temperature and stirred for 7 h. The reaction mixture was then cooled to room temperature and stirred for 4 h. After the reaction was completed, it was cooled to room temperature and subjected to filtration. The filtrate was distilled at atmospheric pressure and the resulting concentrate was extracted with saturated brine solution, the organic phases were combined and dried with anhydrous sodium sulfate. The dried organic phase was filtered and subjected to atmospheric pressure distillation to collect the 55-60 °C/1.33 kPa fraction to give 2-ethyl-3-methylpyrazine in more than 93.5% product yield.

References

[1] Patent: CN107556250, 2018, A. Location in patent: Paragraph 0024; 0029; 0035; 0041; 0049; 0053

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