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CAS No.: 497-18-7
EC Number: 207-837-2
Carbohydrazide = 1,3-Diaminourea
Carbohydrazide is the chemical compound with the formula OC(N2H3).
Carbohydrazide is a white, water-soluble solid.
Carbohydrazide decomposes upon melting.
A number of carbazides are known where one or more N-H groups are replaced by other substituents.
They occur widely in the drugs, herbicides, plant growth regulators, and dyestuffs.
Industrially the compound is produced by treatment of urea with hydrazine:
OC(NH2)2 + 2 N2H4 → OC(N2H3)2 + 2 NH3
Carbohydrazide can also be prepared by reactions of other C1-precursors with hydrazine, such as carbonate esters.
Carbohydrazide can be prepared from phosgene, but this route cogenerates the hydrazinium salt [N2H5]Cl and results in some diformylation.
Carbazic acid is also a suitable precursor:
N2NH3CO2H + N2H4 → OC(N2H3)2 + H2O
The molecule is nonplanar.
All nitrogen centers are at least somewhat pyramidal, indicative of weaker C-N pi-bonding.
The C-N and C-O distances are about 1.36 and 1.25 Å, respectively.
Oxygen scrubber: carbohydrazide is used to remove oxygen in boiler systems. Oxygen scrubbers prevent corrosion.
Precursor to polymers: carbohydrazide can be used as a curing agent for epoxide-type resins.
Photography: carbohyrazide is used in the silver halide diffusion process as one of the toners.
Carbohydrazide is used to stabilize color developers that produce images of the azo-methine and azine classes.
Carbohydrazide has been used to develop ammunition propellants, stabilize soaps,and used a reagent in organic synthesis.
Heating carbohydrazide may result in an explosion.
Carbohydrazide is harmful if swallowed, irritating to eyes, respiratory system, and skin.
Carbohydrazide is toxic to aquatic organisms.
CAS Number : 497-18-7
ChEBI : CHEBI:61308
ChemSpider : 66578
ECHA InfoCard: 100.007.126
PubChem CID : 73948
UNII : W8V7FYY4WH
CompTox Dashboard (EPA) : DTXSID5038757
Carbohydrazide is a derivative of hydrazine, has strong reducibility, can be used as an intermediate in the manufacture of energetic materials, and can also be directly used as a component of rocket explosives and propellants.
Carbohydrazide is used as the oxygen scavenger for boiler water.
Carbohydrazide is the most advanced material used in boiler water deoxidation in the world.
Carbohydrazide has low toxicity, high melting point and deoxidation efficiency far greater than the materials currently used.
Carbohydrazide is an ideal product for safety and environmental protection.
Carbohydrazide has a wide range of uses in industry:
1. Carbohydrazide can be used as an oxygen scavenger for boiler water in the field of water treatment.
Carbohydrazide is the most advanced material used in boiler water deoxidation in the world.
Carbohydrazide has low toxicity, high melting pointanddeoxidation efficiency far greater than the materials currently used.
Carbohydrazide is an ideal safety and environmental protection product.
As a boiler oxygen scavenger, the carbohydrazide can be placed in water, or an aqueous solution thereof can also be used.
The amount of carbohydrazide in 1 mol of O 2 is 0.5 mol, and an appropriate excess is used.
The applicable temperature range is 87.8-176.7 °C.
The timing of using carbohydrazide after thermal deaeration.
The reaction of carbohydrazide with oxygen is as follows: CON4H6 2O2 = 2N2 3H2O CO2
2. Carbohydrazide can also be used as a component of rocket propellants.
3. Also, the hydrogen atom attached to the nitrogen atom is easily substituted by other groups.
4. In the textile industry, it can also be used as a crosslinking agent for elastic fibers, a scavenger for formaldehyde, and an antioxidant for pigments such as carotene.
5. In addition, the addition of an appropriate amount of carbohydrazide to the phenolic bactericide-containing soap can prevent discoloration and rancidity.
6. As a chemical raw material and chemical intermediate, it is widely used in medicine, herbicides, plant growth regulators, dyes and other industries.
Color developing and soap quality stabilizers, rubber antioxidants, metal passivators, etc.
Chemical Name: Carbohydrazide
Synonyms: 1,3-Diaminomocovina;1,3-diamino-ure;4-amino-semicarbazid;Cabazide;Carbazic acid, hydrazide;carbazicacid,hydrazide;Carbodihydrazide;Carbonic acid, dihydrazide
CAS No.: 497-18-7
Molecular Formula: CH6N4O
Molecular weight:90.08
Appearance:White crystal
Assay: 99.9%
CAS Number: 497-18-7
Molecular Weight: 90.08
Beilstein/REAXYS Number:1747069
EC Number: 207-837-2
MDL number: MFCD00007591
PubChem Substance ID: 24892343
REACH No. : A registration number is not available for this substance as the substance or its uses are exempted from registration, the annual tonnage does not require a registration or the registration is envisaged for a later registration deadline.
Description of first aid measures
General advice: Consult a physician. Show this safety data sheet to the doctor in attendance.
If inhaled: If breathed in, move person into fresh air.
If not breathing, give artificial respiration.
Consult a physician.
In case of skin contact: Wash off with soap and plenty of water.
Consult a physician.
In case of eye contact: Flush eyes with water as a precaution.
If swallowed: Never give anything by mouth to an unconscious person.
Rinse mouth with water.
Consult a physician.
Most important symptoms and effects, both acute and delayed: The most important known symptoms and effects are described in the labelling and/or in section 11
Indication of any immediate medical attention and special treatment needed: No data available
Extinguishing media
Suitable extinguishing media: Use water spray, alcohol-resistant foam, dry chemical or carbon dioxide.
Special hazards arising from the substance or mixture: Carbon oxides, Nitrogen oxides (NOx)
Advice for firefighters: Wear self-contained breathing apparatus for firefighting if necessary.
Personal precautions, protective equipment and emergency procedures: Use personal protective equipment.
Avoid dust formation. Avoid breathing vapours, mist or gas.
Ensure adequate ventilation. Avoid breathing dust.
For personal protection see section 8.
Environmental precautions:Prevent further leakage or spillage if safe to do so.
Do not let product enter drains.
Discharge into the environment must be avoided.
Methods and materials for containment and cleaning up: Pick up and arrange disposal without creating dust.
Sweep up and shovel.
Keep in suitable, closed containers for disposal.
Exposure controls
Appropriate engineering controls: Handle in accordance with good industrial hygiene and safety practice.
Wash hands before breaks and at the end of workday.
Personal protective equipment
Eye/face protectio: Face shield and safety glasses Use equipment for eye protection tested and approved under appropriate government standards such as NIOSH (US) or EN 166(EU).
Skin protection: Handle with gloves.
Gloves must be inspected prior to use.
Use proper glove removal technique (without touching glove's outer surface) to avoid skin contact with this product.
Dispose of contaminated gloves after use in accordance with applicable laws and good laboratory practices.
Wash and dry hands.
The selected protective gloves have to satisfy the specifications of Regulation (EU) 2016/425 and the standard EN 374 derived from it.
Body Protection: Complete suit protecting against chemicals, The type of protective equipment must be selected according to the concentration and amount of the dangerous substance at the specific workplace.
Respiratory protection: For nuisance exposures use type P95 (US) or type P1 (EU EN 143) particle respirator.
For higher level protection use type OV/AG/P99 (US) or type ABEK-P2 (EU EN 143) respirator cartridges.
Use respirators and components tested and approved under appropriate government standards such as NIOSH (US) or CEN (EU).
Control of environmental exposure Prevent further leakage or spillage if safe to do so.
Do not let product enter drains.
Discharge into the environment must be avoided.
Carbonyl dihydrazine is a carbohydrazide obtained by formal condensation between hydrazinecarboxylic acid and hydrazine.
Carbohydrazide is a carbohydrazide and a one-carbon compound.
Carbohydrazide derives from a hydrazine and a carbazic acid.
Carbohydrazide, also called Carbodihydrazide, is a high performance oxygen scavenger which can be used in all types of boilers.
Carbohydrazide is a white, water-soluble solid that decomposes upon melting point around 153°C.
Carbohydrazide can be used as oxygen scrubber as direct replacement for Hydrazine in any boiler without the associated safety hazards and handling precautions.
The product is based on volatile chemistry and so leaves no dissolved solids and minimal ammonia to the boiler system.
Carbohydrazide does provide outstanding protection from oxygen corrosion together with excellent feed water and boiler system passivation.Carbohydrazide reacts directly with oxygen.
Carbohydrazide helps prevent oxygen damage and continues to passivate metal surfaces during wet lay-up.
Carbohydrazide can also be used as a curing agent for epoxide-type resins.
Product Features:
Carbohydrazide is a white crystalline thin and short columnar crystal or white powder at room temperature.
Carbohydrazide is insoluble in alcohol, easily soluble in water with dissolution absorbing heat.
Carbohydrazide is insoluble in alcohol, ether, and benzene.
Owing to that, it is a kind of derivative of hydrazine and thus having strong reduction ability.
Carbohydrazide is non-toxic, and can replace hydrazine and oximes. It has a broad range of application in industry.
For example, it can be used as the oxygen scavenging agent of boiler water in the field of water treatment and is regarded as most advanced materials for oxygen scavenging of boiler water.
Carbohydrazide has a low toxicity and high melting point with its deoxidizing efficiency being far greater than the current materials used and is a idea product for both safety and environmental protection; it can also be used as a rocket propellant components; moreover, owing to that its hydrogen atoms attached to the nitrogen atom is easily substituted by other groups, it can be used as the cross-linking agents of elastic fibers in the textile field, the formaldehyde scavenger, as well as the antioxidant of carotene pigment.
In addition, adding an appropriate amount of carbohydrazide to the phenol fungicides containing can play a role on preventing discoloration and rancidity.
As a chemical raw material and chemical industry intermediates, it is widely used in medicine, herbicides, plant growth regulators, dyes and other industries.
Oxygen scavenger of the boiler water
When acting as the oxygen scavenger of boiler water, carbohydrazide may be directly added into the water while its aqueous solution can also be used.
The usage amount of carbohydrazide for scavenging 1mol O2 is 0.5mol, and should be appropriately in excess.
The proper temperature range is 87.8-176.7 ℃. The optimal time for applying carbohydrazide is after the thermal scavenging of oxygen.
The reaction of oxygen and carbohydrazide is as follows: CON4H6 + 2O2 = 2N2 + 3H2O + CO2
Reference quality standards
Item Index
Appearance: fine white crystals or white short columnar crystals
Purity% ≥98.0%
Free hydrazine ≤250.0mg/L
Loss of weight by drying ≤0.2%
PH (12% aqueous solution) 8.45 ± 1.25
Uses:
Carbohydrazide is widely used in the production of pharmaceuticals, herbicides, plant growth regulators, dyes, etc.
carbohydrazide is a derivative of hydrazine with a strong reduction.
Carbohydrazide can be not only used as the intermediates for producing energy-containing materials, but also can be used directly as the components of explosives and propellants.
Carbohydrazide can be used as the preservative of refinery equipment and can also be used as the oxygen scavenger of boiler water treatment agent It can be used as the cross-linking agent of the elastic fiber in the field of chemical fiber industry it can be used as the chemical raw materials and chemical industrial intermediates and is widely used in medicine, herbicides, plant growth regulators, dyes and other industries.
Carbohydrazide can be used as the component of the rocket propellant, the stabilizer of color development and soap quality, the antioxidants of rubber, the oxygen scavenger of boiler water, and the passivation agent of metal.
Carbohydrazide is a derivative of hydrazine with a strong reduction.
Carbohydrazide can be used as the intermediate of producing energy-containing materials and also be used directly for the components of explosives and rocket propellant.
Carbohydrazide can also be used as the oxygen scavenger of boiler water and is the most advanced materials for scavenging oxygen of boiler water in the world today.
Carbohydrazide has low toxicity, high melting point and a deoxidation efficiency being far greater than the materials currently used.
Carbohydrazide is an ideal product for both safety and environmental protection. In addition, it can be used as the cross-linking agent of the elastic fiber in the field of chemical fiber industry.
Carbohydrazide can also be used as the chemical raw materials and chemical industrial intermediates and is widely used in medicine, herbicides, plant growth regulators, dyes and other industries.
The above information is edited by the chemicalbook of Dai Xiongfeng.
Category: toxic substances
Toxicity grading : poisoning
Explosive and hazardous characteristics: it is explosive upon heating; it can generate explosive diazide compound upon reaction with nitrous acid.
Flammability and hazard characteristics: thermal decomposition into toxic nitric oxide gas.
Storage characteristics: Treasury: ventilation, low-temperature and drying; it should be stored separately from strong acids and strong oxidants.
Extinguishing agent: Water, carbon dioxide, dry powder, foam.
Chemical Properties: white powder
Uses: Organic intermediate and photographic chemical.
Definition: ChEBI: A carbohydrazide obtained by formal condensation between hydrazinecarboxylic acid and hydrazine.
Safety Profile: Poison by intravenous and intraperitoneal routes.
Reacts with nitrous acid to form the explosive carbonic dazide.
When heated to decomposition it emits toxic fumes of NOx.
Carbohydrazide, which is marketed under different trade names, was believed to be a good alternative to hydrazinethat provides all of the additional benefits desired of an alternative oxygen scavenger of being safe to handle but without the deleterious impact on the cycle chemistry.
Trial tests with carbohydrazide on one of Al-Jubail Power Plant's boilers provided evidence that it is a good alternativeto hydrazine.
After two weeks of optimization, it was found that maintaining residual hydrazine in the range of30–40 µg · kg–1 in feedwater (economizer inlet) was an appropriate method of controlling the dose rate of carbo -hydrazide and hence provided the optimum conditions for passivating the boiler.
Accordingly, a dosing rate of0.7 mg · kg–1 of carbohydrazide was found satisfactory for running the boiler smoothly.
This paper is a summary of the initial trials performed 12 years ago and serves as an introduction to a second articlewhich will be published later this year in this journal.
During the past 12 years, SWCC has been using carbohydrazidein all of its 8 plants.
SWCC has done some studies with different brands and with 6–12 % carbohydrazide used in thesteam cycle as well as during lay-up – this experience will be presented in the next paper.
Usage:
Carbohydrazide can be used as an oxygen scavenger to prevent corrosion especially in a boiler feed system, rocket propellant components, color images and the quality of soap stabilizers, antioxidants rubber, boiler water deoxidants, and metal passivation agents.
Carbohydrazide is also used as an intermediate for organic synthesis.
Package and Storage:
Packed in 25kg or 50kg in woven bag or in fiber drum.
Store in a cool, dry, well-ventilated area away from incompatible substances.
Keep container closed when not in use.
CAS Number: 497-18-7Appearance:
White Crystalline PowderAssay: 98.0% minOdour:
Odourless.Water : 0.5% maxSpecific
Gravity: 1.0200g/cm3.Melting point: 153 C min
Water : 0.5% maxMolecular weight: 90.09
Moisture: 0.2 MaxUse:It can be used as an oxygen scavenger to prevent corrosion especially in boiler feed system, a rocket propellant components, color images and the quality of soap stabilizers, antioxidants rubber, boiler water deoxidants and metal passivation agents, it also used as an intermediate for orgnic synthesis.
What is Carbohydrazide?
Carbohydrazide is used primarily as an oxygen scrubber in water treatment systems.
Carbohydrazide is added also to control corrosion.
Carbohydrazide is also used as a curing agent for epoxide-type resins, to stabilize soaps, as a reagent in organic synthesis, and to develop ammunition propellants.
Carbohydrazide is a safer alternative to hydrazine.
Carbohydrazide reacts with oxygen at low temperatures and pressures, and the products of the reaction are volatile.
Heating carbohydrazide may result in an explosion. Carbohydrazide, like hydrazine, will also passivate metal surfaces.
Carbohydrazide Exposure and Health Risks
Carbohydrazide is an irritant capable of causing reactions to the skin, eyes, and respiratory tract.
Carbohydrazide can cause an allergic reaction when contacting skin.
Carbohydrazide is toxic if swallowed.
Carbohydrazide is also very toxic to aquatic organisms.
Regulations
There are no listed regulations or restrictions for carbohydrazide levels in water.
Measuring Carbohydrazide
Dissolved carbohydrazide concentration in water can be measured in units of parts per million (ppm).
We carry a kit from CHEMetrics that determines carbohydrazide levels in water from 0-0.50 ppm.
Carbohydrazide is well known that hydrazine possesses excellent reducing action and oxygen scavenging property.
Hydrazine as an oxygen scavenger has been widely used for the feedwater treatment of PWR secondary side and fossil power plants in the world.
Recently, PWRS have operated with All Volatile Treatment (AVT) employing high hydrazine content water chemistry.
Carbohydrazide is reported that the use of hydrazine as a scavenger of trace quantities of dissolved oxygen reduce the corrosion of balance-of-plant materials in the recommended pH range in PWRs.
High hydrazine water chemistry is expected to yield a reduction in the corrosion product transport to the steam generators.
However, there is some concern over health and safety issues related to use of hydrazine.
Carbohydrazide is listed up as one of safety substitute of hydrazine.
Carbohydrazide has replaced hydmzine in 20% of the United States electric utility industry.
Moreover, it is reported that the reducing action and oxygen scavenging property of carbohydrazide is comparable with that of hydrazine, and that in particular, at low temperature, its oxygen scavenging property is superior to that of hydrazine.
In USA, some good results concerning the corrosion restriction effect of carbohydrazide has been reported.
On the other hand, the result of electrochemical measurements at Kewanuee Nuclear Power Plant shows carbohydrazide has no deleterious effect.
However, the fundamental property of carbohydrazide, such as thermal decomposition rate, reducing action and oxygen scavenging property, has not been adequately clarified.
A hydrazide consisting of hydrazine carrying one or more carboacyl groups.
BESCHREIBUNG
This water miscible (aqueous) embedding medium prevents the loss of lipids caused by organic solvents and also the clouding of tissue observed during specific reactions involving the use of metal-lic fixatives (e.g., OsO4 and Potassium Permanganate).
The GACH embedding medium is prepared by adding Carbohydrazide to 50% Glutaraldehyde in a final concentration of 150 mg/ml, (e.g., 1.5g of Carbohydrazide to 10ml of 50% Glutaraldehyde).
The mixture is carried out in a pre-cooled beaker kept in an ice bath, using a magnetic stirrer.
The Carbohydrazide is added in three portions, and stirred rapidly for 15 minutes after each of the additions.
Carbohydrazide can be employed at neutral pH and cured at 37°C. The stock solution can be stored for several months at -20°C without deterioration.
Tissue Preparation:
Fixation: Tissues are fixed in the conventional way with concentrations of 2 to 5% Glutaraldehyde and rinsedwith the buffers.
Dehydration: Dehydrate according to the following schedule with aqueous dilutions of GACH.
20% GACH + 80% H20 3 hours or overnight
50% GACH + 50% H20 2 - 4 hours
80% GACH + 20% H20 2 - 4 hours
100% GACH 1 - 2 hours
This procedure is carried out in a cold room or in vials immersed in ice (1°C).Particular specimens, (e.g., erythrocites) can be embedded in the undiluted medium, suspended directly in 100% GACH, [Dodge, et al]).
Embedding is carried out by removing the tissue from the last 100% GACH and placing it on a small droplet of fresh GACH on a dental wax plate at room temperature.
Polymerization is obtained by placing the plate in an incubator at 37°C for 8 - 14 hours.
Sectioning: The droplets of polymerized GACH can be cemented on blank epoxy blocks, trimmed and then sectioned on the ultramicrotome using diamond or glass knives.
Polymerized GACH is no longer soluble in water; therefore, the sections can float on the surface of the water in the boat of the knife.
The thickness of the sections can be judged by interference color similar to epoxy sections.
To increase contrast on the cellular components, sections can be stained with aqueous Uranyl Acetate and Lead Citrate.
Carbohydrazide is added to boiler system water as an oxygen scavenger to control corrosion.
Carbohydrazide is a safer alternative to hydrazine, which is toxic. Carbohydrazide reacts with oxygen at low temperatures and pressures.
The products of the reaction are volatile and do not contribute dissolved solids to the boiler water.
Like hydrazine, carbohydrazide will also passivate metal surfaces.
The test kits employ the PDTS chemistry.
Carbohydrazide reduces ferric iron to the ferrous state, and the ferrous iron reacts with PDTS (3-(2-pyridyl)-5,6-bis(4-phenylsulfonic acid)-1,2,4-triazine disodium salt) to form a peach-pink colored complex in direct proportion to the carbohydrazide concentration.
Test results are expressed as ppm (mg/L) carbohydrazide.
Kit comes in a plastic case and contains everything needed to perform 30 tests: Refill, Comparator, Activator Solution, 25 mL sample cup, and instructions
Carbohydrazide (CH6N4O) is a potential substitute to hydrazine in fuel cell applications.
This paper presents a theoretical study on the adsorption of carbohydrazide on Au(111) and Au3Ni(111) surfaces using first principles calculations based on density functional theory.
Results show that without van der Waals correction in the calculations, carbohydrazide weakly physisorbs on Au(111), corroborating the experimentally observed high overpotential requirement for carbohydrazide oxidation on Au catalyst.
An enhanced reactivity is observed by alloying Au with Ni due to the emergence of a localized d-band near the Fermi level that interacts strongly with the HOMO of carbohydrazide.
On Au3Ni(111), a N–Ni bond between carbohydrazide and the surface is formed, characterized by the hybridization of N–pz and Ni–dzz states.
These results pose insights into the use of 3d transition metals as alloying components in enhancing the reactivity of Au catalyst for carbohydrazide oxidation.
Carbohydrazide is prepared by reacting dimethyl carbonate with hydrazine hydrate.
Carbohydrazide single crystal has been cultured with slow evaporation method.
Carbohydrazide molecular structure and crystal structure have been determined by X-ray single crystal diffraction technique.
The obtained results shows that the crystal belongs to Crystal system of Monoclinic, space group P2(1)/n with crystal parameters of
a = 3.725(1),
b = 8.834(2),
c = 11.96(3),
β = 91.97(1)°,
V = 392.23(2) 3,
Z = 4,
D c = 1.522 g/cm3,
μ = 0.128 mm−1,
F0 0 0) = 192.
Based on the crystal data, we have also carried quantum chemistry calculations on the title compound using the B3LYP and MP2 method with cc-pVTZ basis set.
The calculation results further demonstrate the molecular structure of title compound and its coordination properties.
Carbohydrazide kinetics of the Pu(VI) reduction with carbohydrazide in nitric acid solutions was studied by spectrophotometry.
Carbohydrazide reaction rate increases with increasing carbohydrazide concentration and temperature and decreases with increasing HNO3 concentration.
Carbohydrazide reaction order with respect to Pu, carbohydrazide, and HNO3 is 1, 2.3, and–3, respectively.
Carbohydrazide activation energy of the reaction is 111 kJ mol–1.
Carbohydrazide based oxygen scavenger contains corrosion owing to dissolved oxygen, without adding any inorganic solids to the boiler water.
This particular class of oxygen scavenger does not decompose into organic acid species and works by promoting the formation of passivating metal oxide films without interfering with the action of other treatment chemicals.
Carbohydrazide minimizes oxygen induced corrosion and pitting, iron oxide deposition and scaling of feed-water lines, de-aerators, and internal steam boiler with these advanced boiler oxygen scavengers.
This boiler water treatment is mainly available in two variants - powder and liquid. In solid form, it is white crystalline in appearance, completely soluble in water, decomposes around 153°C/ 307.4 F.
Carbohydrazide liquid variant is based on volatile chemistry which leaves no dissolved solids, and ammonia to the boiler system.
Carbohydrazide prevents corrosion by forming a protective passive film on metal and boosting pH in condensate line, thereby increasing the shelf-life of boilers.
Although Carbohydrazide may be added to the boiler system at any point, it is most efficient to treat the boiler feed water, preferably as it comes from the de-gasifiers.
Residence times prior to steam formation should be maximized to obtain maximum corrosion protection.
Carbohydrazide is an effective oxygen scavenger and metal passivator over the entire range of temperatures to which the boiler is generally subjected.
Key Features and Benefits of this Boiler Water Treatment:
Long time protection and control against corrosion
Non carcinogenic nature
Easy to dose
Promotes passivation on metal surfaces
Non residual
Chemtex Speciality Ltd is one of the largest manufacturers of Carbohydrazide in India, and supplies globally.
Carbohydrazide has been demonstrated to be an efficient formaldehyde-scavenging agent, particularly with dimethyloldihydroxyethylene urea (DMDHEU) resins.
With a given level of carbohydrazide, a lower level of free formaldehyde was achieved with the buffered DMDHEU resin than with the unbuffered.
The nature of the catalyst also had a significant effect on the formaldehyde-scavenging ability of the carbohy drazide.
Although the free formaldehyde is reduced on the fabric initially, it increases after washing.
A solution of the carbohydrazide in the methylated DMDHEU has long-term stability.
This property would permit a preformulated product by the resin manufacturer.
Hydrazine as an oxygen scavenger has been widely used for the feed water treatment of PWR secondary side and fossil power plants in the world.
However, there is some concern over health and safety issues related to use of hydrazine.
Carbohydrazide is listed up as one of alternative oxygen scavengers.
In this study, laboratory tests were performed to examine the thermal decomposition rate of carbohydmzide and its reducing effect on carbon steel corrosion in comparison with hydrazine.
Test results revealed that carbohydrazide was stable below 373K.
The thermal decomposition ratios of carbohydrazide were less than 50% after 20 minutes exposure in the range of 373K to 428K.
Carbohydrazide thermal decomposition rate constant was derived from experimental test data.
The measurement of dissolved oxygen concentration also showed thatcarbohydrazide possessed a fairly good oxygen scavenger property.
Judging from test results mentioned above, it was concluded that carbohydmzide is applicable as an alternative oxygen scavenger for feedwater treatment in PWR and fossil power plant.
Carbohydrazide is an oxygen scavenger often used as a boiler water additive to inhibit corrosion.
Carbohydrazide reacts with oxygen at low temperatures and pressures, thereby removing dissolved oxygen from solution.
The products of the reaction are water and the volatile gases nitrogen and carbon dioxide, which do not contribute dissolved solids to the boiler water.
Carbohydrazide also passivates metallic surfaces.
Carbohydrazide is a safer alternative to the use of the hazardous and carcinogenic compound hydrazine
Carbohydrazide reduces ferric iron to ferrous iron, which then reacts with the PDTS (3-(2-pyridyl)-5,6-bis(4-phenylsulphonic acid)-1,2,4-triazine disodium salt) to form a peach-pink coloured complex directly proportional to the carbohydrazide concentration.
Test results are expressed as ppm (mg/l) carbohydrazide.
Description
Carbohydrazide is used as an oxygen scavenger in water treatment for boilers.
Carbohydrazide is an alternative to the hazardous and potentially carcinogenic hydrazine.
Carbohydrazide reacts with oxygen to make water and nitrogen and urea.
Carbohydrazide also passivates metals and reduces metal oxides.
Carbohydrazide is widely used in the production of drugs, herbicides,rubber, plant growth regulators, and dyestuffs.
Carbohydrazide is white crystal powder. Carbohydrazide is very soluble in water and soluble in alcohol.
Carbohydrazidedecomposes on heating or exposure to uv to form ammonia, hydrogen, and nitrogen, which may be explosive with a blue flame when catalyzed by metal oxides and some metals such as platinum or raney nickel.
Carbohydrazide has dibasic and very reactive properties. Carbohydrazide is used as a component in jet fuels because it produce a large amount of heat when burned.
Carbohydrazide is used as rocket fuel.
Carbohydrazide is used as an oxygen scavenger for water boiler feed and heating systems to prevent corrosion damage.
Carbohydrazide is used as a reducing agent for the recovery of precious metals.
Carbohydrazide is used as a polymerization catalyst and a chain extender in urethane coatings.
Carbohydrazide is used as an auxiliary in photographic industry to prevent discolouration.
Carbohydrazide is used as an intermediate for pharmaceuticals, stabilizers and water treatment chemicals.
Carbohydrazide and its derivatives are versatile intermediates.
They have active applications in organic synthesis for agrochemicals, pharmaceuticals, photographic, heat stabilizers, polymerization catalysts, flame- retardants, blowing agents for plastics, explosives, and dyes.
Recently, hydrazine is applied to lcd (liquid crystal displays) as the fuel to make faster thin-film transistors.
When used as de-oxidant in boiler, put this product into water or use its water solution, the dosage of 0.5mol or above of carbohydrazide for 1mol O2 is preferred.
The suitable temperature range is 87.8-176.7℃.
The reaction for carbohydrazide with O2 is CON4H6+ 2O2= 2N2 + 3H2O + CO2
Hydrazine as an oxygen scavenger has been widely used for the feed water treatment of PWR secondary side and fossil power plants in the world.
However, there is some concern over health and safety issues related to the use of hydrazine.
Carbohydrazide is listed up as one of alternative oxygen scavengers.
In this study, laboratory tests were performed to examine the thermal decomposition rate of carbohydrazide and its reducing effect on carbon steel corrosion in comparison with hydrazine.
Test results revealed that carbohydrazide was stable below 373 K.
The thermal decomposition ratios of carbohydrazide were less than 50% after 20 minutes exposure in the range of 373 K to 428 K.
Its thermal decomposition rate constant was derived from experimental test data.
The measurement of dissolved oxygen concentration also showed that carbohydrazide possessed a fairly good oxygen scavenger property.
Judging from test results mentioned above, it was concluded that carbohydrazide is applicable as an alternative oxygen scavenger for feedwater treatment in PWR and fossil power plant.
Carbohydrazide is used as an oxygen scavenger in water treatment for boilers.
Carbohydrazide is an alternative to the hazardous and potentially carcinogenic hydrazine.
Carbohydrazide reacts with oxygen to make water, nitrogen and urea.
Carbohydrazide also passivates metals and reduces metal oxides converting ferric oxide to ferrous oxide and converting cupric oxide to cuprous oxide.
Carbohydrazide is widely used in the production of drugs, herbicides, plant growth regulators, and dyestuffs.
Carbohydrazide is a white crystalline solid with a melting point of 153-154 °C. It decomposes upon melting.
Carbohydrazide is very water soluble and largely insoluble in organic solvents.
USES:
Oxygen scrubber: carbohydrazide is used as an oxygen scrubber in boiler systems.
Oxygen scrubbers remove oxygen gas from the boiler system to prevent corrosion.
Polymers: carbohydrazide can react with many aromatic compounds to create polymers.
Carbohydrazide can be used as a curing agent for epoxide-type resins.
Photography: carbohyrazide is used in the silver halide diffusion process as one of the toners.
Carbohydrazide is used to stabilize color developers that produce images of the azo-methine and azine classes.
Carbohydrazide has been used to develop propellants stabilize soaps, and used a reagent in organic synthesis
In the secondary systems of pressurized water reactors (PWRs), all volatile treatment (AVT) is applied.
Hydrazine is added as an oxygen scavenger. The authors hypothesized that carbohydrazide would be a harmless alternative to hydrazine.
In the present study, the thermal decomposition and corrosion suppression effects on carbon steel of carbohydrazide were evaluated in comparison with those of hydrazine.
The rate constant of the thermal decomposition of carbohydrazide was evaluated.
The oxygen-scavenging efficiency of carbohydrazide is slightly lower than that of hydrazine.
However, it has been confirmed that corrosion of carbon steel is suppressed more in carbohydrazide solution than in hydrazine solution at 423 K.
Carbohydrazide is considered that carbohydrazide is less reducing at 423 K than hydrazine, and that carbohydrazide suppresses reductive dissolution of iron oxides.
Carbohydrazide can be concluded that carbohydrazide is a promising alternative to hydrazine in the secondary systems of PWRs.
Title: Carbohydrazide
CAS Registry Number: 497-18-7
CAS Name: Carbonic dihydrazide
Additional Names: 1,3-diaminourea
Molecular Formula: CH6N4O
Molecular Weight: 90.08
Percent Composition: C 13.33%, H 6.71%, N 62.20%, O 17.76%
Line Formula: NH2NHCONHNH2
Literature References: Prepd by refluxing diethyl carbonate with hydrazine hydrate: Mohr et al., Inorg. Synth. 4, 32 (1953).
Properties: Crystals from water + ethanol, dec 153-154°.
Freely sol in water.
pH of 1% aq soln ~7.4.
Practically insol in alcohol, ether, chloroform, benzene.
Forms salts with acids.
With nitrous acid it forms the highly explosive carbonyl azide CO(N3)2.
A one-pot, multi-component protocol for the synthesis of a new class of functionalized quinoline carbohydrazide derivatives via reaction of various anilines, dimedone, aromatic aldehydes, and cyanoacetohydrazide is described.
The reactions are completed in the presence of catalytic amount of piperidine, respectively, in melt conditions and then in ethanol/water (1:1) as green solvent at 80°C.
Mild conditions, green medium, short reaction times, simple workup and purification process with no chromatographic technique, and good yields are the main advantages of this method.
Carbohydrazide applications
Final efficiency and yield of equipment that work with steam and water like boilers depend on the chemicals that are used in order to control the corrosion and scaling of the water that is used in the system.
In boilers and other equipment that are made of steel, oxygen may cause Corrosion.
One factor that may increase the risk of corrosion in boilers at high temperatures.
Feedwater that is fed to boilers must contain chemicals that are corrosion inhibitors like hydrazine to control the oxygen scavenging.
But as a matter of fact, hydrazine is extremely toxic due to reports so it can bring about several health problems.
To reduce the risks that are caused by oxygen scavenger chemicals some chemicals are replaced with previous ones like Carbohydrazide.
Carbohydrazide minimized the oxygen content that causes corrosion and also reduces the scaling and iron oxide deposition.
This chemical does not add any inorganic materials to the system.
In order to maximize the corrosion inhibitor efficiency, the residence time should be increased.
Carbohydrazide is a very stable and efficient oxygen scavenger in a wide variety range of temperatures.
Advantageous of Carbohydrazide applied in steam equipment
Low toxicity in comparison with other chemicals;
Easy to manage dose and control it;
Awesome protection against corrosion;
Without any residual in the system.
Synthesis of Carbohydrazide
In Industrial-scale the chemical is synthesized by the reaction of urea with hydrazine:
OC (NH2)2 + 2 N2H4 → OC (N2H3)2 + 2 NH3
The other way of this compound synthesis is through the reaction of carbonate ester and hydrazine.
Other Oxygen Scavenger chemicals which are available on the Shanghai Chemex group website in this category are:
Cyclohexylamine
Morpholine
Hydrazine Hydrate
SYNONYMS
Carbohydrazide
497-18-7
Carbonic dihydrazide
1,3-Diaminourea
Carbonohydrazide
Carbazide
Carbodihydrazide
Hydrazine, carbonyldi-
Hydrazine, carbonylbis-
Carbazic acid, hydrazide
Urea, N,N'-diamino-
Semicarbazide, 4-amino-
Carbonic acid, dihydrazide
Cabazide
Karbazid
Hydrazinecarboxamide, N-amino-
Urea, 1,3-diamino-
carbonyl dihydrazine
Hydrazinecarboxylic acid, hydrazide
1,3-Diaminomocovina
Carbonohydrazid
UNII-W8V7FYY4WH
carbonodihydrazide
NSC 1934
N,N'-diaminourea
4-aminosemicarbazide
carbonylbis-hydrazine
hydrazinecarbohydrazide
N-aminohydrazinecarboxamide
W8V7FYY4WH
N-aminohydrazine carboxamide
hydrazide hydrazinecarboxylic acid
MFCD00007591
Carbohydrazide, 97%
Karbazid [Czech]
1,3-Diaminomocovina [Czech]
EINECS 207-837-2
CH6N4O
BRN 1747069
AI3-52397
carbonyldihydrazide
Urea,3-diamino-
Urea,N'-diamino-
Carbohydrazide, 98%
1,3-bis(azanyl)urea
