Dicyandiamide, DCD, DCDA, Cyanoguanidine, 461-58-5

Dicyandiamide, DCD, DCDA, Cyanoguanidine, 461-58-5

CAS: 461-58-5

Molecular Formula: C2H4N4

Names and Identifiers

Physico-chemical Properties

Risk and Safety

Upstream Downstream Industry

Nature

White rhomboid crystalline powder, non-flammable. The relative density was 1. 400. The melting point was 207-209 °c. Slightly soluble in water and ethanol, insoluble in ether and benzene. The dried dicyandiamide is stable in nature.

Preparation Method

lime nitrogen is used as raw material to hydrolyze with water, and the hydrolyzed liquid in suspension obtained from the reaction is filtered under reduced pressure to remove Ca (OH)2 filter residue, the filtrate was introduced into carbon dioxide for decalcification to produce cyanamide solution, which was then polymerized under alkaline conditions and at a temperature of 74 ℃.
After filtration, cooling crystallization, separation and drying, the finished dicyandiamide is obtained.

Introduction

The solubility in water is 2.26% at 13 ℃, and the solubility in hot water is relatively large. When the aqueous solution is gradually decomposed at 80 ℃ to produce ammonia, the solubility in anhydrous ethanol is 1.2% at 13 ℃, which is soluble in liquid ammonia and insoluble in benzene and chloroform. Low toxicity, half lethal dose (mice, oral)>4000mg/kg.

Use

This product is the raw material of melamine plastic, and it is also the intermediate of synthesizing medicine, pesticide and dye. In medicine for the preparation of guanidine nitrate, sulfonamide drugs. It can also be used to prepare thiourea, nitrocellulose stabilizer, rubber vulcanization accelerator, steel surface hardening agent, printing and dyeing fixing agent, adhesive, synthetic detergent, compound fertilizer and so on.

Safety

• This product may damage the skin, should pay attention to prevent the occurrence of rash.
• This product is packed in a woven bag lined with plastic bag or in a paper bag made of five layers of kraft paper. The mouth of the bag shall be sealed tightly and shall not leak. The net weight of each bag is 25±0, and the average net weight of each bag is up to 25kg. Should be stored in a cool, dry, ventilated place, not with the oxidant storage. In the transport of loading and unloading should be moisture-proof, light and light.

Operational disposition and storage

[precautions for operation]
Closed operation, partial ventilation. Operators must be specially trained and strictly follow the operating procedures. It is recommended that operators wear self-priming filter type dust masks, chemical safety glasses, anti-virus penetration work clothes and rubber gloves. Stay away from fire and heat source. No smoking is allowed in the workplace. The use of explosion-proof ventilation systems and equipment. Dust should be avoided. Avoid contact with oxidants, acids and alkalis. Handling should be light and light unloading, to prevent packaging and container damage. Fire fighting equipment and emergency treatment equipment for leakage shall be provided with corresponding varieties and quantities. Harmful substances may remain in the empty container.

[precautions for storage]
Store in a cool, ventilated warehouse. Keep away from fire and heat source. It should be stored separately from oxidants, acids and alkalis, and mixed storage should be avoided. With the corresponding varieties and quantity of fire fighting equipment. The storage area shall be provided with suitable materials for containment of the leakage.
Exposure control/personal protection

[engineering control]
Closed operation, partial ventilation.

[respiratory system protection]
When the dust concentration in the air exceeds the standard, the self-suction filter dust mask must be worn. Air respirators should be worn during emergency rescue or evacuation.

[eye protection]
Wear chemical safety glasses.

[body protection]
Wear anti-virus infiltration work clothes.

[hand protection]
Wear rubber gloves.

[other protection]
After completion of work, shower and dressing. Clothing contaminated with toxicants should be stored separately and used after washing. Pay attention to personal hygiene.

Stability and reactivity

[prohibited objects]

strong oxidant, strong acid, strong alkali.

Introduction

dicyandiamine, commonly known as dicyandiamide, is a latent curing agent that has long been used, and is widely used in coatings, single packaging adhesives, film adhesives, etc. Dicyandiamine is white crystal, melting point 207~209 ℃, toxicity is small, but difficult to dissolve in epoxy resin. It is reported that dicyandiamide can be dissolved in epoxy resin with a solvent, but dicyandiamide is still mixed with epoxy resin after being pulverized, heated and mixed on a triple roll, or processed by an extruder. Usually no accelerator mixture, the applicable period of more than half a year.

The curing mechanism of dicyandiamide is more complex, in addition to four active hydrogen in the reaction, cyano also has reactivity. In addition, dicyandiamide also has the role of catalytic curing agent. For E-51 epoxy resin, the theoretical dosage of dicyandiamide is 11g per g resin, while the actual dosage is 4~10G, especially for Solid epoxy resin.

Regulatory Information

This product is not controlled

trait

white crystalline powder. The solubility in water is 2.26% at 13 C, and the solubility in hot water is larger. Ammonia gas is produced when the aqueous solution is gradually decomposed at 80 °c. The solubility of anhydrous ethanol and ether in 13 degrees C, respectively, 1.26% and 0.01%. Soluble in liquid ammonia, insoluble in benzene and chloroform. Relative density (d254)1.40. Melting point 209.5 °c. Low toxicity, median lethal dose (mice, by mouth)>4000mg/kg.

storage

sealed dry storage.

Use

cobalt, nickel, copper and palladium were assayed. Organic Synthesis. Nitrocellulose stabilizer. Hardener. Detergent. Vulcanization accelerators. Resin synthesis. As a raw material of guanidine salt and cyanodiamine trimer. Various guanidine salts can be produced by reacting dicyandiamide with an acid. Dicyandiamide and phenyl nitrile reaction of benzenetricyandiamine is paint, laminate, molding powder intermediates

is the raw material of melamine, is also the intermediate of the synthesis of medicines, pesticides and dyes

used in organic synthesis and resin synthesis, also used as vulcanization accelerator and hardener

is a raw material for the production of melamine. It is also an intermediate for pharmaceuticals and dyes. In medicine for the preparation of guanidine nitrate, sulfonamide drugs. It can also be used to prepare thiourea, guanidine, nitrocellulose stabilizer, rubber vulcanization accelerator, steel surface hardening agent, printing and dyeing fixing agent, artificial leather filler and adhesive.

The main uses of dicyandiamide are:

1. as a raw material of guanidine salt and tricyanodiamine. Various guanidine salts can be produced by reacting dicyandiamide with an acid. The benzenetricyandiamine obtained by the reaction of dicyandiamide and phenylnitrile is an intermediate of coating, laminate and molding powder.
2. used as a dye fixing agent, dicyandiamide resin prepared by reaction of dicyandiamide and formaldehyde can be used as a dye fixing agent.
3. dicyandiamide fertilizer, dicyandiamide compound fertilizer can control the activity of nitrifying bacteria, so that the transformation rate of nitrogen fertilizer in soil is adjusted, the loss of nitrogen is reduced, and the use efficiency of fertilizer is improved.
4. as a fine chemical intermediate. In medicine for the preparation of guanidine nitrate, sulfonamides, etc.; Also used to prepare thiourea, nitrocellulose stabilizer, rubber vulcanization accelerator, steel surface hardening agent, artificial leather filler, adhesive, etc. The pharmaceutical intermediate 5-azacytosine can be obtained from the reaction of dicyandiamide with formic acid.

curing agent for epoxy powder coatings.

cobalt, nickel, copper and palladium were assayed. Organic Synthesis. Nitrocellulose stabilizer. Hardener. Detergent. Vulcanization accelerators. Resin synthesis

Quality Indicators

Toxicology

[acute toxicity]

LD50:>4000 mg/kg (mouse oral);>3000 mg/kg (rabbit oral)

Overview of risk

health hazard

harmful to the body after inhalation, ingestion or absorption through the skin. However, the risk of acute poisoning is minimal.

[risk of explosion]

This product is flammable and irritating.

First aid measures

[skin contact]
Remove contaminated clothing and rinse with running water.

[eye contact]
Lift the eyelid and rinse with running water or normal saline. The patient visited hospital.

[inhalation]
The patient was discharged from the site to a place with fresh air.

ingestion
Drink enough warm water to induce vomiting. The patient visited hospital.

Fire protection measures

[hazard characteristics]
In the case of ammonium nitrate, potassium chlorate and its salts can occur a strong reaction, causing an explosion. By high heat decomposition, produce cyanide and nitrogen oxides highly toxic smoke.

[harmful combustion products]
Nitric oxide, hydrogen cyanide.

[fire extinguishing method]
Fire-fighting personnel must wear filter-type gas masks (full face masks) or isolated respirators, and full-body fire-fighting and virus-proof clothing to put out fire in the upward wind direction. Fire extinguishing agents: water mist, foam, dry powder, carbon dioxide, sand.
Emergency treatment for leakage

[emergency treatment]
Isolation leakage of contaminated areas, restricted access. Cut off the fire source. Emergency personnel are advised to wear dust masks (full face mask) and anti-virus clothing. Wash with a large amount of water, wash water diluted into the wastewater system. If there is a large amount of leakage, it will be collected, recovered or transported to the waste disposal site for disposal.

Waste disposal

[method of disposal]

refer to relevant national and local regulations before disposal. Disposal by incineration is recommended. The nitrogen oxides discharged from the incinerator are removed by a scrubber.

[transport considerations]

The packaging should be complete and the loading should be safe. During transportation, it is necessary to ensure that the container does not leak, collapse, fall or damage. Mixing with oxidant, acids, alkalis and edible chemicals is strictly prohibited. During transport should be protected against exposure to sunlight, rain, and high temperature. Vehicles should be thoroughly cleaned after transportation.

Production method

production method 1

lime nitrogen (calcium cyanamide) was hydrolyzed with water to remove calcium hydroxide by filtering off the obtained suspension-form hydrolyzed liquid calcium cyanamide hydrogen hydroxide, and the filtrate was decalcified by passing carbon dioxide to obtain a cyanamide liquid. The cyanamide is then polymerized under weakly basic conditions. The temperature at the maximum rate of dicyandiamide formation is related to pH: pH 9.7 at 50 ℃; pH 9.1 at 80 ℃; pH 100 at 8.8 ℃. After polymerization under these conditions, the dicyandiamide is obtained by cooling, crystallization, separation and drying. Industrial dicyandiamide content of 99%, per ton of product consumption of lime nitrogen (nitrogen more than 21%) 4239kg.

production method 2

The lime nitrogen method is used to hydrolyze the lime nitrogen with water, and the suspended calcium hydrogen cyanide hydrolysate obtained by the reaction is filtered under reduced pressure to remove the calcium hydroxide filter residue, the carbon dioxide produced by the decomposition of limestone is subjected to decalcification reaction to generate cyanoammonia solution, which is polymerized under alkaline conditions, filtered, cooled, crystallized, separated and dried to obtain dicyandiamide.
2CaCN2+2H2O→Ca(HCN2)2+Ca(OH)2
Ca(HCN2)2+CO2+H2O→2NH2CN+CaCO3
2NH2CN→(NH2CN)2

Reference Information