guanidine Property

Melting point:

~50°

Boiling point:

82.3°C (rough estimate)

Density 

1.6000 (rough estimate)

refractive index 

1.5950 (estimate)

storage temp. 

-20°C Freezer

solubility 

DMSO (Slightly), Methanol (Slightly)

form 

Solid

pka

pKa ~12.5(at 25℃)

color 

White

EPA Substance Registry System

Guanidine (113-00-8)

Safety

RIDADR 

1759

HazardClass 

8

PackingGroup 

II

Hazardous Substances Data

113-00-8(Hazardous Substances Data)

Toxicity

LD50 i.p. in mice: 350 mg/kg (Podlesnaya)

Hazard and Precautionary Statements (GHS)

Symbol(GHS)

Signal word

Warning

Hazard statements

H319Causes serious eye irritation

H410Very toxic to aquatic life with long lasting effects

Precautionary statements

P264Wash hands thoroughly after handling.

P264Wash skin thouroughly after handling.

P273Avoid release to the environment.

P280Wear protective gloves/protective clothing/eye protection/face protection.

P337+P313IF eye irritation persists: Get medical advice/attention.

P391Collect spillage. Hazardous to the aquatic environment

P501Dispose of contents/container to..…

guanidine Chemical Properties,Usage,Production

Chemical Properties

Colorless crystals. Soluble inwater and alcohol. Combustible. Guanidine is a strong monobasic Bronsted base, which absorbs water and carbon dioxide from the air and forms strongly alkaline solutions with water and alcohols; the pH of a 20 wt % aqueous solution is ca. 13.5 (25 ℃). In aqueous solution at elevated temperature guanidine is hydrolyzed to urea; airtight alcohol solutions are stable. Guanidine is infinitely soluble in water, ethanol, methanol, and dimethylformamide.

Uses

Guanidine is an intermediate in synthesizing N-Formylguanidine (F700505), which is used in the preparation of Amiloride (A578700), a sodium channel blocker used as a diuretic drug.

Uses

Organic synthesis

Production Methods

Guanidine is formed (1) by heating ammonium thiocyanate to 180 °C, (2) by ammonolysis of orthocarbonates, C(OC2H5)4 + 3NH3 → (NH2)2C=NH + 4C2H5OH, (3) by ammonolysis of chloropicrin, Cl3CNO2 + 7NH3 → NH2)2 C=NH + 3NH4Cl + N2 + 3H2O, (4) by ammonolysis of cyanogen chloride, ClCN + NH3 → ClC(NH2)=NH → HN=C=NH → (NH2)2 C=NH.
Guanidine forms salts with acids, e.g., guanidine nitrate, HNC(NH2)2 · HNO3. By heating at 120 °C for several hours, a mixture of ammonium thiocyanate and dicyanodiamide, guanidine thiocyanate solution is obtained by extracting with water. Treating guanidine with a mixture of nitric and sulfuric acids forms nitroguanidine which is reduced by zinc and acetic acid to aminoguanidine.
By treating aminoguanidine (1) with dilute acid or alkali, there is obtained, first, semicarbazide, finally hydrazine; (2) with nitrous acid, diazoguanidine which is decomposed by alkali into alkali azide (e.g., NaN3) plus cyanamide (H2N·CN) plus water.

Definition

ChEBI: Guanidine is an aminocarboxamidine, the parent compound of the guanidines. It is a one-carbon compound, a member of guanidines and a carboxamidine. It is a conjugate base of a guanidinium.

Agricultural Uses

Carbamidine is another name for guanidine. It is a crystalline basic compound related to urea. It forms a number of salts which are used as fertilizers. Guanidine phosphate is an example.

Purification Methods

Crystallise it from water/EtOH under nitrogen. It is very deliquescent and absorbs CO2 from the air readily. [Jones Trans Faraday Soc 55 524 1959, Beilstein 3 H 82, 3 I 39, 3 II 69, 3 III 154, 3 IV 148.]