Courses
Courses for Kids
Free study material
Offline Centres
More
Store Icon
Store

Hydrazine

ffImage
Last updated date: 29th Mar 2024
Total views: 390k
Views today: 7.90k
hightlight icon
highlight icon
highlight icon
share icon
copy icon

What is Hydrazine?

Hydrazine is an inorganic compound that is also a simple pnictogen hydride with a chemical formula N2H4 that has ammonia like order and is a colourless flammable liquid. Unless it is handled in a solution like that of the NH2NH2· xH2O, it is highly toxic in nature. The hydrazine hydrate market in the world accounted for $350 million in the year 2015. Hydrazine is primarily used as a foaming agent for the preparation of polymer foam. But it is also used as a precursor to polymerisation catalysts, pharmaceuticals, and agrochemicals, along with long-term propellant that could be stored is primarily applicable for the in-space spacecraft propulsion.

Each subunit of H2N-N is pyramidal in molecular structure. As the molecule adopts a gauche conformation, the bond distance of the N-N single bond is calculated which is equal to .45 Å (145 pm). The rotational barrier is observed to be twice that of ethane. These structural properties resemble the gaseous hydrogen peroxide as it is seen to be adopting anticlinal conformation that is skewed in nature and therefore is bound to experience a strong rotational barrier. 

In 2015, the foam blowing agent used up about two million tons of hydrazine hydrate. It is also used for the preparation of gas precursors that are used in airbags and is primarily used in rocket fuel of various kinds. For both nuclear and conventional electric power plants, hydrogen is used as an oxygen scavenger that controls the concentration of dissolved oxygen for reducing corrosion. Hydrogen thus refers to a group of organic substances that are derived when one or more hydrogen atoms are replaced in hydrogen by some organic groups.


(Image will be Uploaded soon)


Properties of Hydrazine

Physical Properties

Properties

Values

N2H4 chemical name

Hydrazine

Hydrazine formula

N2H4

The molecular weight 

32.0452 g/mol

Appearance 

Colourless, fuming, oily liquid

Odour 

ammonia-like

Density

1.021 g/cm3

Melting Point

2 °C; 35 °F; 275 K

Boiling point

114 °C; 237 °F; 387 K114 °C; 237 °F; 387 K

Solubility in water

Miscible

N2H4 structure


(Image will be Uploaded soon)


logP

0.67

Vapour pressure

1 kPa (at 30.7 °C)

Acidity

8.10 (N2H5+)

Basicity

5.90

Conjugate acid

Hydrazinium

Refractive index

1.46044 (at 22 °C)

Viscosity 

0.876 cP

Structural properties

Molecular shape

Triangular pyramidal at N

Dipole moment

1.85 D

Thermochemistry

Specific Heat Capacity

25.23 g-cal/mol-deg

Standard Molar entropy

121.52 J/K mol

Standard enthalpy of formation

50.63 kJ/mol


Synthesis of Hydrazine

The key route of the diverse route that has been developed for the synthesis of hydrazine is the creation of an N-N single bond. Out of the many routes that have been developed over a period of time, they are categorised broadly into two major parts. One that uses chlorine oxidants and results in the generation of salts and one that does not. 


Oxidation of Ammonia via Oxaziridines from Peroxide

Hydrogen is developed by the reaction of ammonia with hydrogen peroxide in the presence of a ketone catalyst. It is a procedure known as the peroxide process. It is also sometimes referred to as the Pechiney y-Ugine-Kuhlmann process, the Atofina–PCUK cycle, or ketazine process.  The net reaction is as follows:-

2 NH3 + H2O2 →  N2H4 + 2 H2O

By this route, the imine is first produced by the condensation of ketone and ammonia, which is then oxidised by hydrogen peroxide in order to produce oxaziridine. It is a three-member drink that contains carbon, Oxygen and nitrogen. By the treatment of ammonia, hydrogen is produced from oxaziridine. This process results in the formation of a single nitrogen bond. Therefore the hydrazone condenses with one or more equivalent of the ketone.


(Image will be Uploaded soon)


The Azeem that is formed undergoes hydrolysis to give hydrogen name and the regeneration of the ketone, the methyl ethyl ketone.

ME(Et)CNNC(Et)ME + 2H2O → 2ME(Et)CO  +  N2H4


Chlorine Based Oxidations

Sodium hypochlorite which is an active ingredient in many beeches along with ammonia without the use of any ketone catalyst is the main product that results in the formation of hydrazine. The process is known as the Olin Raschig process, which was first introduced in the year 1907. This method depends on the reaction of mono chloro amine with ammonia that creates the nitrogen-Nitrogen single bond with HCl as a byproduct. The reaction is as follows:-

NH2Cl + NH3 → H2NNH2 + HCl 

In the above process, urea can also be oxidised in place of ammonia. In the case of urea as well, sodium hypochlorite serves as an antioxidant. The following reaction is as follows.

(H2N)2CO + NaOCl + 2NaOH →  H2NNH2 + NaCl + H2O + Na2CO3.

This process is mainly practised in Asia as it produces a significant amount of by-products. The predecessor of the peroxide process is the Bayer kitazin process. This process incorporates sodium hypochlorite in place of hydrogen peroxide as an oxidant. For each equivalent of hydrogen and equivalent of salt is produced by this method like all the hypochlorite based routes.


Hydrazine Uses

The hydrogen uses are as follows:-

  1. For several pharmaceuticals and pesticides, hydrogen acts as a precursor. These applications often involve the conversion of hydrazine into heterocyclic rings such as pyridazine and pyrazoles. Some examples of the bioactive hydrogen derivatives that have been commercialized include hydrazine sulphate,  diimide, triadimefon,  cefazolin, rizatriptan, anastrozole fluconazole, metazachlor, metamitron, metribuzin, paclobutrazol, diclobutrazole, propiconazole and dibenzoylhydrazine. 

  2. Hydrazine is majorly used as a blowing agent. Specific compounds are known as azodicarbonamide and azobisisobutyronitrile produces 100–200 mL of gas per gram of precursor. When hydrazine reacts with the sodium nitrite it results in the formation of gas that is a reagent in air-bags. 

  3. It was used as a component of the rocket fuel in world war II. it is also used as a precursor to polymerisation catalysts, pharmaceuticals, and agrochemicals, along with long-term propellant that could be stored is primarily applicable for the in-space spacecraft propulsion.

FAQs on Hydrazine

1. What is Hydrazine utilized for?

Ans. Since the results are generally nitrogen gas and water, hydrazine is a helpful reductor. In this way it is utilized in water boilers and warming frameworks as a cell reinforcement, an oxygen forager and an erosion inhibitor.

2. What is Hydrazine made of?

Ans. Hydrazine, N2H4, is an exceptionally receptive, combustible, dreary fluid with a smell near that of alkali. It's essentially utilized in malignancy research as rocket powers, evaporator water cures, concoction reactants, drugs, and. Hydrazine is a concoction compound consisting of nitrogen and hydrogen particles, which acts like water.

3. Is Hydrazine a base?

Ans. Hydrazine is an Arrhenius base is a more vulnerable base than smelling salts since the more electronegative gathering NH2 has the-I impact on the neighboring nitrogen's solitary pair of electrons, rendering it less significant for protonation.

4. Why is Hydrazine utilized as a rocket fuel?

Ans. Hydrazine is utilized as a rocket fuel, as it responds with oxygen to shape nitrogen gas and water fume exothermically. The warmth discharged and the expansion in the quantity of gas moles give a push. Hydrazine being combusted is an exothermic response.

5. For what reason is Hydrazine unsteady?

Ans. Hydrazine is a profoundly harmful and conceivably unsteady substance that looks similar to smelling salts potentially in light of the fact that it is produced using two alkali atoms (with H2 misfortune) that are bound together. The recipe is N2H4, and its piece to some degree takes after the twisted hydrogen peroxide synthesis.

6. What is the oxidation state of nitrogen in hydrazine?

The oxidation state of nitrogen in hydrazine is -2, and that of hydrogen is +1. We can simply calculate the oxidation state of nitrogen in hydrazine using its chemical formula N2H4. Hydrogen can have a +1 oxidation state, and there are four hydrogen atoms. So, by assuming the oxidation state of nitrogen is equal to x.

2x + 4 = 0

2x = -4

x = -2

So oxidation state of nitrogen is -2 in hydrazine.

7. What is the formula of phenylhydrazone ?


The formula of phenylhydrazine is C6H8N2. It is a chemical compound, which is a product of phenol and hydrazine addition reaction. 

C6H5OH + N2H4C6H5HN2H2+H2O