Hydrazine Hydrate, Hydrazine Monohydrate​​​​​​​, Hydrazinium Hydroxide, Hydrazine Hydroxide, 10217-52-4, 7803-57-8

Hydrazine Hydrate, Hydrazine Monohydrate, Hydrazinium Hydroxide, Hydrazine Hydroxide, 10217-52-4, 7803-57-8

Hydrazine Hydrate

Molecular Formula: H₆N₂O or N₂H₄ • H₂O
Molecular Weight: 50.06 g/mol
Chemical Name: Hydrazine Hydrate
CAS Numbers: 7803-57-8 and 10217-52-4

General Information and Description

Hydrazine Hydrate is a colorless, clear, hygroscopic liquid with strong reducing properties. Chemically, it is the hydrated form of a hydrazine molecule (N₂H₄) combined with one water molecule (H₂O). It is an important industrial chemical intermediate used across various sectors. Commercially, it is typically available in concentrations of 24-35%, 40-55%, 60-85%, and 100% (anhydrous, for special applications); the most common commercial forms are 40-55% and 60-85% solutions.

Other Names (Synonyms)

• Hydrazine Monohydrate

• Hydrazinium Hydroxide

• Diamine Hydrate

• Hydrazine Hydroxide

• 7803-57-8, 10217-52-4

Production Method

Several industrial methods are used to produce Hydrazine Hydrate. The most common processes today are the Ketazine process and the Hydrogen Peroxide (PCUK) process.

1. Ketazine Process (Improved):
This method involves the reaction of a ketone (usually Methyl Ethyl Ketone - MEK), ammonia, and an oxidizing agent (such as sodium hypochlorite, though hydrogen peroxide is more common now) to form a ketazine intermediate. The resulting ketazine is separated in a phase separator and then hydrolyzed to yield hydrazine hydrate and recover the original ketone. Recent patents describe processes using recyclable solid acetamide and ammonium acetate activators for ketazine formation, coupled with catalyst-free hydrolysis to achieve energy efficiency.

2. Hydrogen Peroxide (PCUK) Process:
In this method, hydrogen peroxide (H₂O₂) is used as the oxidizing agent in the presence of an amide (such as acetamide).

• Reaction Medium: Methyl Ethyl Ketone (MEK) serves as the reaction medium.

• Catalyst: Catalysts containing rare earth elements, silica gel, and phosphate compounds are used to increase yield.

• Intermediate and Hydrolysis: The reaction synthesizes a water-insoluble methyl ethyl ketazine intermediate. After separating this intermediate with a phase separator, it is hydrolyzed to obtain Hydrazine Hydrate. This method has the advantages of producing no chlorinated by-products and having lower energy consumption.

Physical and Chemical Properties

• Physical Appearance: Clear, colorless liquid.

• Odor: Slight, characteristic odor reminiscent of ammonia.

• Melting Point: Between -51.7 °C and -57 °C.

• Boiling Point: Between 117.2 °C and 120-121 °C (depending on concentration).

• Density: Approximately 1.03 g/cm³ at 25 °C.

• Solubility: Miscible with water and alcohol in all proportions.

• Vapor Pressure: 5 mmHg at 25 °C.

• Vapor Density: Heavier than air (>1).

• Refractive Index: n20/D ~ 1.428 - 1.431.

• Flash Point: 96 °C (closed cup).

Applications and Uses

Due to its strong reducing properties and chemical reactivity, Hydrazine Hydrate is used across a very wide range of industries.

1. Water Treatment (Corrosion Inhibitor):

• Oxygen Scavenger: It prevents corrosion in steam boilers and high-pressure heating systems by reacting with dissolved oxygen. It also reacts with iron oxide layers to form a protective magnetic layer (magnetite).

2. Chemical Industry (Intermediate and Reducing Agent):

• Polymerization and Blowing Agents: Used in the production of blowing agents like azodicarbonamide (ADC). It is essential for creating porous structures in products such as plastics, rubber, and sports shoe soles.

• Chemical Synthesis: Acts as a strong reducing agent in the synthesis of various organic and inorganic compounds.

3. Agriculture (Agrochemicals):

• Herbicide and Fungicide Production: It is a key intermediate in the synthesis of many agrochemicals, such as triazole fungicides and plant growth regulators.

4. Pharmaceutical Industry:

• API Synthesis: Used in the synthesis of certain active pharmaceutical ingredients (APIs) used in the treatment of diseases like cancer and tuberculosis.

5. Aerospace and Defense Industry:

• Rocket Fuel: Used as a monopropellant in spacecraft and missiles, or as a component in high-energy fuel blends.

Reactivity and Reactions

• Strong Reducing Agent: It can reduce many metal ions (e.g., silver, mercury) to their metallic forms.

• Acid-Base Reactions: Reacts with acids to form hydrazinium salts (N₂H₅⁺).

• Oxidation: Reacts violently with oxidizing agents; upon oxidation, it releases nitrogen gas (N₂) and water.

Commercial Concentrations and Purity

Hydrazine Hydrate is available on the market in different concentrations:

• 24-35% Solutions

• 40-55% Solutions (The most common industrial form)

• 60-85% Solutions (Common commercial form)

• 100% Hydrazine (Anhydrous): Usually produced for specialized applications (e.g., rocket fuel) and is less commonly traded directly.

• Purity: Commercial grades typically have a purity of 98.0% or higher.

Safety and Handling

• Classification: Dangerous, Toxic, Carcinogenic, Corrosive.

• GHS Pictograms:

  • GHS06 (Skull and Crossbones - Acute Toxicity)

  • GHS05 (Corrosion)

  • GHS08 (Health Hazard - Carcinogenicity)

  • GHS09 (Environmental Hazard)

• GHS Signal Word: Danger.

• GHS Hazard Statements (H-Statements - Key ones):

  • H301 + H311: Toxic if swallowed or in contact with skin.

  • H314: Causes severe skin burns and eye damage.

  • H317: May cause an allergic skin reaction.

  • H331: Toxic if inhaled.

  • H350: May cause cancer.

  • H410: Very toxic to aquatic life with long-lasting effects.

• Risk and Safety Precautions:

  • UN Number: 2030 (Hydrazine aqueous solution).

  • Packaging Group: I or II (depending on concentration).

  • Wear protective gloves, goggles, face shield, and appropriate respiratory protective equipment during handling.

  • Store in well-ventilated areas, away from heat, sparks, and oxidizing agents.

  • Prevent any release into water sources and the environment.

Alternatives

Alternatives to Hydrazine Hydrate vary depending on the application:

• As an Oxygen Scavenger: Sodium sulfite, carbohydrazide, diethylhydroxylamine (DEHA).

• As a Reducing Agent: Sodium borohydride, sodium dithionite.