Isoquinoline Chemical Properties

Melting point:

26-28 °C(lit.)

Boiling point:

242-243 °C(lit.)

Density 

1.099 g/mL at 25 °C(lit.)

FEMA 

2978 | ISOQUINOLINE

refractive index 

n20/D 1.623(lit.)

Flash point:

225 °F

storage temp. 

2-8°C

solubility 

5g/l

pka

5.42(at 20℃)

form 

Low Melting Solid

color 

Light brown

PH

7.5 (5g/l, H2O, 20℃)

Water Solubility 

practically insoluble

JECFA Number

1303

Merck 

14,5222

BRN 

107549

InChIKey

AWJUIBRHMBBTKR-UHFFFAOYSA-N

CAS DataBase Reference

119-65-3(CAS DataBase Reference)

NIST Chemistry Reference

Isoquinoline(119-65-3)

EPA Substance Registry System

Isoquinoline (119-65-3)

Safety Information

Hazard Codes 

T

Risk Statements 

22-24-38-52/53-36/38-21/22-45

Safety Statements 

36/37-45-36/37/39-61-53

RIDADR 

UN 2811 6.1/PG 3

WGK Germany 

2

RTECS 

NW6825000

TSCA 

Yes

HazardClass 

6.1

PackingGroup 

II

HS Code 

29334900

Toxicity

LD50 orally in rats: 360 mg/kg (Smyth)

MSDS

• Language:English Provider:SigmaAldrich
• Language:English Provider:ACROS
• Language:English Provider:ALFA

Isoquinoline Usage And Synthesis

Chemical Properties

Colorless flaky crystal or liquid, similar fragrance to bitter almonds and Chervil, sweet taste, melting point 23℃，boiling point 243℃, soluble in ethanol and non-volatile oil, diluted inorganic acid and most organic solvents, slightly soluble in water.

Usage

• A kind of Spice
• Mainly used for the preparation of vanilla spice.   
• Used in the production of pesticides, medicine, rubber accelerator, color film sensitizing agent, dyes, anion exchange resin and so on.
• Used as gas chromatographic stationary liquid and analytical reagent,
• Used in the pharmaceutical industry.
• Used for the production of drugs for prevention and treatment of schistosomiasis (praziquantel), antimalarial, chemical reagents, etc.
• Isoquinoline can be oxidized to produce Pyridine carboxylic acid And Its derivatives can be used for the production of color films and dyes.  It can be used as Iron preservative, soluble phenolic resin curing agent, etc. Its Addition compounds formed with metals can be used for the quantitative determination of nickel and cadmium and the qualitative determination of noble metal. Isoquinoline can also be used as a catalyst in the benzoylation reaction and polymerization of α-olefin.

Usage limitation

FEMA(mg/kg): Soft drinks 0.25,, cold drinks 0.25, sweets1.0； bakery products 0.004-1.0, moderate use (FDA§172．515，2000).

Preparation

Crude quinoline containing 83% quinoline, 15% isoquinoline and 2% methyl quinoline can be used as the raw material for the production of isoquinoline. However, the Distillation section from 237.5-239.5℃ and 243-246℃ is generally collected and used as the raw material for the extraction of isoquinoline. 13-28% of 2-methyl quinoline and 3.9% quinoline can be separated from this distillation section in the form of hydrochloride salt.
The isoquinoline fraction reacted with 98% sulfuric acid at 35℃ in alcohol solution to produce isoquinoline sulfonate. Isoquinoline sulfonate crystallizes faster than its homologues in the cooling process. After filtration, recrystallization was carried out with 85% ethanol, and then decomposed with 20% ammonia water. The generated oil layer was firstly washed with water, and then rectified to collect the fraction at242-243℃to obtain Isoquinoline with purity greater than 95%  It is separated by repeated freezing the coal tar with the boiling rangeat 238～250℃.

Content analysis

Determined by Gas chromatography and liquid chromatography and the chromatographic test conditions are the same as α-allyl ionone (03411).

Category

flammable liquid

Toxicity grade

middle toxic

Toxicity

GRAS(FEMA)

Acute toxicity

Oral – rat LD50: 360mg/kg

Stimulus data

Skin-rabbit  10 mg/24h mild;  eye-rabbit 250 μg severe.

Flammability hazard characteristics

Flammable in case of fire, high temperature and oxidants, Combustion produces toxic nitrogen oxide smog.

Storage

Completely packed, handle with care; Ventilated warehouse, away from open flame, high temperature, separated from strong acids.

Fire extinguishing agent

foam, carbon dioxide, dry powder, dry sand, water spray.

Description

Isoquinoline has an odor reminiscent of benzaldehyde and anise. Isoquinoline may be obtained from coal tar (238 - 250°C boiling fraction); it is isolated as the sulfate or as is by repeated freezing.

Chemical Properties

Isoquinoline has a heavy sweet balsamic, herbaceous odor.

Chemical Properties

LIGHT BROWN LOW MELTLING SOLID

Occurrence

Reported found in milk and dried bonito; also occurs in coal tar, where it is formed during the dry distillation of coal

Uses

Manufacture of pharmaceuticals (such as nicotinic acid), dyes, insecticides, rubber accelerators, and in organic synthesis.

Uses

It is used in the manufacture of dyes, pharmaceuticals,and insecticides, and as an antimalarialagent.

Preparation

Obtained from coal tar (238 to 250°C boiling fraction); it is isolated as the sulfate or as is by repeated freezing

Definition

ChEBI: An ortho-fused heteroarene that is a benzopyridine in which the N atom not directly attached to the benzene ring.

Synthesis Reference(s)

The Journal of Organic Chemistry, 29, p. 2240, 1964 DOI: 10.1021/jo01031a031
Synthesis, p. 288, 1974

Hazard

Toxic by ingestion.

Health Hazard

The toxic properties of this compound aresimilar to those of quinoline. It is moderatelytoxic in rats and rabbits by oral routeand skin absorption. The oral LD50 value inrats is 360 mg/kg. The irritation effects onskin and eyes in rabbits were moderate tosevere. Carcinogenicity due to isoquinolinein animals or humans is not known. The histidinereversion–Ames test for mutagenicitywas inconclusive.

Fire Hazard

Noncombustible liquid (solid).

Purification Methods

Dry isoquinoline with Linde type 5A molecular sieves or Na2SO4 and fractionally distil at reduced pressure. Alternatively, it can be refluxed with, and distilled from, BaO. It is also purified by fractional crystallisation from the melt and distilled from zinc dust. It forms a phosphate (m 135o) and a picrate (m 223o), which are purified by crystallisation, and the free base can be recovered and distilled. [Packer et al. J Am Chem Soc 80 905 1958.] The procedure for purification via the picrate comprises the addition of quinoline to picric acid dissolved in the minimum volume of 95% EtOH to yield yellow crystals which are washed with EtOH and air dried before recrystallising from acetonitrile. The crystals are dissolved in dimethyl sulfoxide (previously dried over 4A molecular sieves) and passed through a basic alumina column, on which picric acid is adsorbed. The free base in the effluent is extracted with n-pentane and distilled under vacuum. Traces of solvent from small quantities are removed by vapour phase chromatography. The hydrochloride crystallises from EtOH with m 193o. [Mooman & Anton J Phys Chem 80 2243 1976, Beilstein 20 II 236, 20 III/IV 3410, 20/7 V 333.]

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