Pyrazine Chemical Properties

Melting point:

50-56 °C (lit.)

Boiling point:

115-116 °C (lit.)

Density 

1.031 g/mL at 25 °C (lit.)

refractive index 

1.5235

FEMA 

4015 | PYRAZINE

Flash point:

132 °F

storage temp. 

Store below +30°C.

solubility 

SOLUBLE

pka

0.65(at 27℃)

form 

Crystals

color 

White

Specific Gravity

1.031

Odor

at 0.10 % in propylene glycol. pungent sweet corn like roasted hazelnut barly

Odor Type

nutty

Water Solubility 

SOLUBLE

Sensitive 

Hygroscopic

Merck 

14,7957

JECFA Number

951

BRN 

103905

Dielectric constant

2.7999999999999998

Stability:

Stable. Highly flammable. Incompatible with acids, oxidizing agents.

LogP

-0.26

CAS DataBase Reference

290-37-9(CAS DataBase Reference)

NIST Chemistry Reference

Pyrazine(290-37-9)

EPA Substance Registry System

Pyrazine (290-37-9)

Safety Information

Hazard Codes 

Xi,F

Risk Statements 

36/37/38-11

Safety Statements 

26-36-16

RIDADR 

UN 1325 4.1/PG 2

WGK Germany 

3

RTECS 

UQ2015000

TSCA 

T

HazardClass 

4.1

PackingGroup 

III

HS Code 

29339990

MSDS

• Language:English Provider:1,4-Diazine
• Language:English Provider:SigmaAldrich
• Language:English Provider:ACROS
• Language:English Provider:ALFA

Pyrazine Usage And Synthesis

Description

Pyrazine is a heterocyclic aromatic organic compound and can be reacted to obtain diverse pyrazine derivatives. Pyrazines are important contributors to the flavor of various roasted, toasted, or similarly heated foods. Pyrazine derivatives exhibit a wide variety of aromas in food, e.g. 2-methoxy-3-isopropylpyrazine produces a green pea odor. Pyrazines and pyrazine derivatives are typically used as flavor agent. Pyrazines and Pyrazine derivatives are also used as fragrances.

References

[1] T.B. Adamsa, J. Doullb, V.J. Feronc, J.I. Goodmand, L.J. Marnette, I.C. Munrof, P.M. Newberneg, P.S. Portogheseh, R.L. Smithi, W.J. Waddellj and B.M. Wagnerk, The FEMA GRAS assessment of pyrazine derivatives used as flavor ingredients, Food and Chemical Toxicology, 2002, vol. 40, 429-451

Chemical Properties

white crystals or powder

Chemical Properties

Pyrazine has a strong pyridine-like odor. Some reports compare the taste of pyrazine to cooked spinach or rancid peanuts

Occurrence

Pyrazine has been detected in several food products including papayas, asparagus, peanuts, popcorn, soybeans, corn, French fries, bread, cheese, milk, eggs (boiled), chicken (fried), beef (cooked), shrimp, clams, beer, sherry, malt, coffee and tea (green).

Uses

Pyrazine is used as a flavoring agent. It serves as a component of some herbs in traditional Chinese medicine. It is employed as pharmaceutical intermediates, perfume intermediates and involved in the preparation of other chemicals. In addition to this, it is used in the production of pyrazine 1-oxide.

Definition

ChEBI: A diazine that is benzene in which the carbon atoms at positions 1 and 4 have been replaced by nitrogen atoms.

Definition

A heterocyclic aromatic compound with a six-membered ring containing four carbon atoms and two nitrogen atoms.

Definition

pyrazine: An unsaturated heterocycliccompound having two nitrogenatoms in a six-membered ring,C₄H₄N₂; r.d. 1.03; m.p. 52°C; b.p.115°C. Pyrazine is a symmetric diazine.

Preparation

Prepared by cyclization of α-amino ketones, which were produced by the reduction of isonitroso ketones to yield the dihydropyrazines, which are dehydrogenated with mercury(I) oxide or copper(II) sulfate or sometimes with atmospheric oxygen.

Aroma threshold values

300 ppm (odor threshold in water)

General Description

Pyrazine is a 1,4-diazine and an electron-deficient N-heteroarene found in several natural products, APIs, agrochemicals, and functional materials.

Purification Methods

Distil pyrazine in steam and crystallise it from water. Purify also by zone melting. [Beilstein 23 H 91, 23 II 80, 23 III/IV 899, 23/5 V 351.]

Pyrazine(290-37-9)Related Product Information

• DBU
• Sulfanilic acid
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• p-Toluic acid
• p-Phenylenediamine
• Glipizide
• 4-Aminobenzoic acid
• 4-Nitrobenzoic acid
• 4-Hydroxybenzoic acid
• 4-Hydroxybenzaldehyde
• 2-cyclohexyl-carbonyl-1,3,4,6,7,11b-hexahydro-2h-pyrazine(2,1-a)isoquinoline-4-one
• Pyrazole
• Phenazine
• 2,3-Pyrazinedicarboxylic acid
• 2-Pyrazinecarboxylic acid
• ALLOXAZINE
• 2-Chloropyrazine
• LUMICHROME