The Raschig process for the production of

hydroxylamine Hydroxylamine is an inorganic compound with the formula . The material is a white crystalline, hygroscopic compound.Greenwood and Earnshaw. ''Chemistry of the Elements.'' 2nd Edition. Reed Educational and Professional Publishing Ltd. pp. 431–43 ...

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 some ...

es developed by German chemist

Friedrich Raschig Friedrich August Raschig (also called Fritz Raschig) (8 June 1863 – 4 February 1928) was a German chemist and politician. He was born in Brandenburg an der Havel. After he received his PhD in 1884 from the University of Berlin for his work with ...

. 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 The bisulfite ion (IUPAC-recommended nomenclature: hydrogensulfite) is the ion . Salts containing the ion are also known as "sulfite lyes". Sodium bisulfite is used interchangeably with sodium metabisulfite (Na2S2O5). Sodium metabisulfite disso ...

towards hydroxylamine di

sulfonate In organosulfur chemistry, a sulfonate is a salt or ester of a sulfonic acid. It contains the functional group , where R is an organic group. Sulfonates are the conjugate bases of sulfonic acids. Sulfonates are generally stable in water, non-ox ...

, which is hydrolysed to

hydroxylammonium sulfate Hydroxylammonium sulfate (NH3OH)2SO4, is the sulfuric acid Salt (chemistry), salt of hydroxylamine. It is primarily used as an easily handled form of hydroxylamine, which is explosive when pure. Synthesis Hydroxylammonium sulfate can be obtained ...

. Most of the hydroxylamine produced is used in the manufacture of

caprolactam Caprolactam (CPL) is an organic compound with the formula (CH2)5C(O)NH. This colourless solid is a lactam (a cyclic amide) of caproic acid. Global demand for this compound is approximately five million tons per year, and the vast majority is used ...

, the precursor to the polymer

Nylon 6 Nylon 6 or polycaprolactam is a polymer, in particular semicrystalline polyamide. Unlike most other nylons, nylon 6 is not a condensation polymer, but instead is formed by ring-opening polymerization; this makes it a special case in the comparis ...

. The commercially used Raschig process consists of the following steps: *

ammonium carbonate Ammonium carbonate is a salt with the chemical formula (NH4)2CO3. Since it readily degrades to gaseous ammonia and carbon dioxide upon heating, it is used as a leavening agent and also as smelling salt. It is also known as baker's ammonia and is ...

solution is prepared by reacting ammonia, carbon dioxide and water *an alkaline solution of

ammonium nitrite Ammonium nitrite, , is the ammonium salt of nitrous acid. It is not used in pure isolated form since it is highly unstable and decomposes into water and nitrogen, even at room temperature. Preparation Ammonium nitrite forms naturally in the air an ...

is formed by reacting ammonium carbonate solution with

nitrogen oxides Nitrogen oxide may refer to a binary compound of oxygen and nitrogen, or a mixture of such compounds: Charge-neutral *Nitric oxide (NO), nitrogen(II) oxide, or nitrogen monoxide *Nitrogen dioxide (), nitrogen(IV) oxide *Nitrogen trioxide (), or ni ...

*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 toxic gas responsible for the odor of burnt matches. It is released naturally by volcanic activ ...

*hydroxylamine disulfonate is hydrolysed to

References

Chemical processes {{Reaction-stub