The Olin Raschig process is a

chemical process In a scientific sense, a chemical process is a method or means of somehow changing one or more chemicals or chemical compounds. Such a chemical process can occur by itself or be caused by an outside force, and involves a chemical reaction of som ...

for the production of

hydrazine Hydrazine is an inorganic compound with the chemical formula . It is a simple pnictogen hydride, and is a colourless flammable liquid with an ammonia-like odour. Hydrazine is highly hazardous unless handled in solution as, for example, hydraz ...

. The main steps in this process, patented by German chemist Friedrich Raschig in 1906 and one of three reactions named after him, are the formation of monochloramine from

ammonia Ammonia is an inorganic chemical compound of nitrogen and hydrogen with the chemical formula, formula . A Binary compounds of hydrogen, stable binary hydride and the simplest pnictogen hydride, ammonia is a colourless gas with a distinctive pu ...

and

hypochlorite In chemistry, hypochlorite, or chloroxide is an oxyanion with the chemical formula ClO−. It combines with a number of cations to form hypochlorite salts. Common examples include sodium hypochlorite (household bleach) and calcium hypochlorite ...

, and the subsequent reaction of monochloramine with ammonia towards hydrazine. The process was further optimised and used by the

Olin Corporation Olin Corporation is an American manufacturer of ammunition, chlorine, and sodium hydroxide. The company traces its roots to two companies, both founded in 1892: Franklin W. Olin's Equitable Powder Company and the Mathieson Alkali Works. Acciden ...

for the production of

anhydrous A substance is anhydrous if it contains no water. Many processes in chemistry can be impeded by the presence of water; therefore, it is important that water-free reagents and techniques are used. In practice, however, it is very difficult to achie ...

hydrazine for aerospace applications.

Process

The commercially used Olin Raschig process consists of the following steps: First,

sodium hypochlorite Sodium hypochlorite is an alkaline inorganic chemical compound with the formula (also written as NaClO). It is commonly known in a dilute aqueous solution as bleach or chlorine bleach. It is the sodium salt of hypochlorous acid, consisting of ...

solution is mixed with a threefold excess of ammonia at 5 °C to give monochloramine. The primary reaction proceeds according to the idealised equation : The monochloramine solution is then added to a 30-fold excess of ammonia at 130 °C and elevated pressure, causing a second reaction : The hydrochloric acid and sodium hydroxide byproducts undergo a secondary reaction to release the byproducts of

water Water is an inorganic compound with the chemical formula . It is a transparent, tasteless, odorless, and Color of water, nearly colorless chemical substance. It is the main constituent of Earth's hydrosphere and the fluids of all known liv ...

and

sodium chloride Sodium chloride , commonly known as Salt#Edible salt, edible salt, is an ionic compound with the chemical formula NaCl, representing a 1:1 ratio of sodium and chloride ions. It is transparent or translucent, brittle, hygroscopic, and occurs a ...

. The overall reaction is thus : Excess ammonia and sodium chloride are removed by distillation, followed by

azeotropic distillation In chemistry, azeotropic distillation is any of a range of techniques used to break an azeotrope in distillation. In chemical engineering, ''azeotropic distillation'' usually refers to the specific technique of adding another component to genera ...

with

aniline Aniline (From , meaning ' indigo shrub', and ''-ine'' indicating a derived substance) is an organic compound with the formula . Consisting of a phenyl group () attached to an amino group (), aniline is the simplest aromatic amine. It is an in ...

to remove water.

References

Chemical processes {{chem-process-stub