hydrazine係咪讀High J 仙?

hydrazine 讀 High Jar 仙

Hydrazine is the chemical compound with formula N2H4. It is widely used in chemical synthesis and is a component in some rocket fuels. With an ammonia-like odor, hydrazine has a liquid range and density similar to water. It has basic properties comparable to ammonia but 15-times weaker. It can be diprotonated only with difficulty.

Synthesis
Theodor Curtius synthesized free hydrazine for the first time in 1889 via a circuitous route.

Hydrazine is produced in the Olin Raschig process from sodium hypochlorite and ammonia, a process announced in 1907. This method relies on the reaction of chloramine with ammonia.

In the Atofina-PCUK_cycle, hydrazine is produced in several steps from acetone, ammonia, and hydrogen peroxide. Acetone and ammonia first react to give the imine followed by oxidation with hydrogen peroxide to the oxaziridine, a three-membered ring containing carbon, oxygen, and nitrogen, followed by ammonolysis to the hydrazone, a process that couples two nitrogen atoms. This hydrazone reacts with one more equivalent of acetone, and the resulting azine is hydrolyzed to give hydrazine, regenerating acetone. Unlike the Raschig process, this process does not produce salt.

Hydrazine can also be produced via the so-called ketazine and peroxide processes.

Uses in chemistry
Hydrazines are part of many organic syntheses, often those of practical significance in pharmaceuticals, such as antituberculants, as well as in textile dyes and in photography.

1. Hydrazone formation
2. Wolff-Kishner reduction
3. Heterocyclic chemistry
4. Sulfonation
5. Deprotection of phthalimides
6. Reducing agent
7. Hydrazinium salts
8. Rocket fuel
9. Other industrial uses
Hydrazine is used in many processes including: production of spandex fibers, as a polymerization catalyst, a blowing agent, in fuel cells, solder, fluxes, and photographic developers, as a chain extender in urethane polymerizations, and heat stabilizers. In addition, a semiconductor deposition technique using hydrazine has recently been demonstrated, with possible application to the manufacture of thin-film transistors used in liquid crystal displays. Hydrazine in a 70% hydrazine, 30% water solution is used to power the EPU (emergency power unit) on the F-16 fighter plane. The explosive Astrolite is made by combining hydrazine with ammonium nitrate.

Safety
Hydrazine is highly toxic and dangerously unstable, especially in the anhydrous form. Symptoms of acute (short-term) exposure to high levels of hydrazine may include irritation of the eyes, nose, and throat, dizziness, headache, nausea, pulmonary edema, seizures, and coma in humans. Acute exposure can also damage the liver, kidneys, and central nervous system in humans. The liquid is corrosive and may produce dermatitis from skin contact in humans and animals. Effects to the lungs, liver, spleen, and thyroid have been reported in animals chronically (long-term) exposed to hydrazine via inhalation. Increased incidences of lung, nasal cavity, and liver tumors have been observed in rodents exposed to hydrazine.

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