Hydrazine N2H4, a colorless liquid having an ammoniacal odor, is the simplest diamine and unique in its class because of the NÀN bond. It was ?rst prepared in 1887 by Curtius as the sulfate salt from diazoacetic ester. Hydrazine and its simple methyl and dimethyl derivatives have endothermic heats of formation and high heats of combustion. Hence, these compounds are used as rocket fuels. Other derivatives are used as gas generators and explosives Hydrazine, a base slightly weaker than ammonia, forms a series of useful salts. As a strong reducing agent, hydrazine is used for corrosion control in boilers and hot-water heating systems; also for metal plating, reduction of noble-metal catalysts, and hydrogenation of unsaturated bonds in organic compounds. Hydrazine is also an oxidizing agent under suitable conditions. Having two active nucleophilic nitrogens and four replaceable hydrogens, hydrazine is the starting material for many derivatives, among them foaming agents for plastics, antioxidants, polymers, polymer cross-linkers and chain-extenders, as well as fungicides, and pharmaceuticals. Hydrazine is also a good ligand; numerous complexes have been studied. Many heterocyclics are based on hydrazine, where the rings contain from one to four nitrogen atoms as well as other heteroatoms. The many advantageous properties of hydrazine ensure continued commercial utility. Hydrazine is produced commercially primarily as aqueous solutions, typically 35, 51.2, 54.4, and 64 wt% N2H4 (54.7, 80, 85, and 100% hydrazine hydrate). Anhydrous hydrazine is produced for rocket propellant and limited commercial applications. 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. Hydrazine hydrate is an organic chemical raw material with extensive applications. The world's capacity to produce hydrazine hydrate has reached more than 200 thousand t/a today (based on 100% hydrazine content). The capacity is divided nearly equally between Europe, Asia and America (35%, 34% and 30%, respectively), with only 1% in other regions. Major producers include Olin of the United States, Bayer of Germany, Ato of France and Mitsubishi Gas Chemical of Japan. The worldwide market demand for hydrazine hydrate is 80 to 90 thousand tons a year. Consumption is roughly 32% for pesticides, 33% for foaming agents, 20% for water treatment agents and 15% for others. Demand will grow steadily in future, with demand in advanced countries declining while demand in developing countries, Asian countries in particular, growing rapidly. There is a very good scope and market potential in this field and new entrepreneurs should venture into this sector.