The Raschig process for the production of
hydroxylamine
Hydroxylamine (also known as hydroxyammonia) is an inorganic compound with the chemical formula . The compound exists as hygroscopic colorless crystals.Greenwood and Earnshaw. ''Chemistry of the Elements.'' 2nd Edition. Reed Educational and Prof ...
is one of three
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 ...
es developed by German chemist
Friedrich Raschig. The main step in this process, patented by Raschig in 1887, is the reduction of
nitrite
The nitrite polyatomic ion, ion has the chemical formula . Nitrite (mostly sodium nitrite) is widely used throughout chemical and pharmaceutical industries. The nitrite anion is a pervasive intermediate in the nitrogen cycle in nature. The name ...
with
bisulfite towards hydroxylamine di
sulfonate
In organosulfur chemistry, a sulfonate is a salt, anion or ester of a sulfonic acid. Its formula is , containing the functional group , where R is typically an organyl group, amino group or a halogen atom. Sulfonates are the conjugate bases of ...
, which is hydrolysed to
hydroxylammonium sulfate.
Most of the hydroxylamine produced is used in the manufacture of
caprolactam, the precursor to the polymer
Nylon 6.
The commercially used Raschig process consists of the following steps:
[
* ammonium carbonate solution is prepared by reacting ammonia, carbon dioxide and water
*an alkaline solution of ]ammonium nitrite
Ammonium nitrite is a chemical compound with the chemical formula . It is the ammonium salt of nitrous acid. It is composed of ammonium cations and nitrite anions . It is not used in pure isolated form since it is highly unstable and decomposes i ...
is formed by reacting ammonium carbonate solution with nitrogen oxides
In atmospheric chemistry, is shorthand for nitric oxide () and nitrogen dioxide (), the nitrogen oxides that are most relevant for air pollution.
These gases contribute to the formation of smog and acid rain, as well as affecting tr ...
*ammonium nitrite is converted to hydroxylamine disulfonate with sulfur dioxide
Sulfur dioxide (IUPAC-recommended spelling) or sulphur dioxide (traditional Commonwealth English) is the chemical compound with the formula . It is a colorless gas with a pungent smell that is responsible for the odor of burnt matches. It is r ...
*hydroxylamine disulfonate is hydrolysed to hydroxylammonium sulfate
References
Chemical processes
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