Dicyandiamide

Chemical properties

white powder

The Uses of Dicyandiamide

Dicyandiamide is a guanidine derivative used in the synthesis of barbiturates,it is also used in the plastics industry (manufacture of melamine).

The Uses of Dicyandiamide

In the plastics industry (manufacture of melamine). In the pharmaceutical industry (barbiturates, guanidine derivatives).

The Uses of Dicyandiamide

Dicyandiamide is used in the synthesis of barbiturates. It is used as a stabilizer of ammonium dinitramide melt. It is used as hardener.

Production Methods

Dicyanodiamide is manufactured by dimerization of cyanamide in aqueous solution. The 25% cyanamide solution produced is adjusted to pH 8–9 and held at approximately 80C for 2 h to give complete conversion. The hot liquor is filtered and transferred to a vacuum crystallizer, where it is cooled. The crystals or dicyanodiamide are separated in continuous centrifuges and passed to rotary driers. In 1990, the total worldwide production of dicyanodiamide was about 30,000 tons.

What are the applications of Application

Dicyanodiammonia, abbreviated as dicy or DCD. It is an organic substance with the chemical formula of c2h4n4. It is a dimer of cyanamide and a cyano derivative of guanidine. Chemical formula c2h4n4. White crystalline powder. Soluble in water, alcohol, ethylene glycol and dimethylformamide, almost insoluble in ether and benzene. Stable when dry. It is a guanidine in which one of the amino hydrogens of guanidine itself is substituted by a cyano group. It is used in the manufacture of fertilizers, pharmaceuticals, explosives, oil well drilling muds, and dyestuffs. It has a role as a curing agent, a flame retardant, a fertilizer, an explosive and a nitrification inhibitor. It is a member of guanidines and a nitrile. The application of nitrification inhibitors has been used as a strategy to promote N utilization efficacy and reduce N2O emissions in paddy Dicyandiamide (DCD) as a widely used nitrification inhibitor inhibits the activity of ammonium-oxidizing bacteria which results in longer ammonium retention and reduces the production of NO2?in soils. DCD efficacy was found to be related to DCD concentration, temperature, moisture, pH, and organic matter content. Studies have shown that leaching DCD from agricultural soils into aquatic ecosystems can strongly change the community composition of benthic stream bacteria and algae and influence stream nutrient cycling stoichiometry. Literature on the mechanisms and benefits of nitrification inhibitors is extensive but there are very few studies focused on the influence of DCD application on other microbes in paddy system.

Definition

ChEBI: Cyanoguanidine is a guanidine in which one of the amino hydrogens of guanidine itself is substituted by a cyano group. It is used in the manufacture of fertilizers, pharmaceuticals, explosives, oil well drilling muds, and dyestuffs. It has a role as a curing agent, a flame retardant, a fertilizer, an explosive and a nitrification inhibitor. It is a member of guanidines and a nitrile.

General Description

Dicyandiamide is commonly used for the curing of epoxy resins. It is a nitrification inhibitor that is said to be capable of reducing nitrate (NO^3-) leaching and nitrous oxide (N₂O) emissions from grazed pasture soils.

Flammability and Explosibility

Non flammable

Synthesis

The calcium hydrogen cyanide suspension obtained from the hydrolysis of calcium cyanamide is filtered under reduced pressure to remove the calcium hydroxide filter residue, and then carbon dioxide is introduced into the filtrate to precipitate the calcium in the form of calcium carbonate to obtain the cyanamide solution. It is polymerized under alkaline conditions, then filtered, cooled, crystallized, separated and dried to obtain dimer cyanamide. The temperature at the maximum rate of dicyandiamide formation is related to pH: pH is 9.7 at 50 ℃; PH 9.1 at 80 ℃; The pH is 8.8 at 100 ℃. After controlled polymerization under these conditions, the finished dicyandiamide is obtained by cooling, crystallization, separation and drying. The content of dicyandiamide in industrial products is 99%, and 4239kg of lime nitrogen (more than 21% nitrogen) is consumed per ton of products.

Purification Methods

Recrystallise cyanoguanidine from water or EtOH. [Beilstein 3 IV 160.]