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Schweizer's reagent is the metal ammine complex with the formula u(NH3)4(H2O)2OH)2. This deep-blue compound is used in purifying cellulose.
It is prepared by precipitating 
It forms an azure solution. Evaporation of these solutions leaves light blue residue of copper hydroxide, reflecting the lability of the copper-ammonia bonding. If conducted under a stream of ammonia, then deep blue needle-like crystals of the tetrammine form. In presence of oxygen, concentrated solutions give rise to nitrites Cu(NO2)2(NH3)''n''. The nitrite results from oxidation of the ammonia.
''Uebergiesst man gereinigte ''Baumwolle'' mit der blauen Flüssigkeit, so nimmt erstere bald eine gallertartige schlüpfrige Beschaffenheit an, die Fasern gehen auseinander und verschwinden und nach einigem Durcharbeiten mit einem Glasstabe hat sich das Ganze in eine schleimige Flüssigkeit verwandelt. Dabei findet nicht die geringste Wärmeentwicklung statt. Hat man nicht eine hinreichende Menge der Flüssigkeit angewendet, so bleibt ein Theil der Fasern noch sichtbar; setzt man dann aber einen Ueberschuss der Lösung hinzu und schüttelt um, so erhält man eine beinahe ''klare blaue Lösung'', die sich, nachdem sie mit Wasser verdünnt worden ist, filtriren lässt."''
(It possesses, namely, to an outstanding degree the capacity ''to dissolve plant fibers at ordinary temperatures.''
If one pours the blue liquid over cleaned ''cotton'', then the former soon assumes a gelatinous, slippery texture, the fibers separate and vanish, and after some kneading with a glass rod, the whole transformed into a slimy liquid. During this, not the least evolution of heat occurred. If one did not use a sufficient quantity of liquid, then a portion of the fibers still remained visible; however, if one then adds an excess of the solution and shakes it, then one obtains a nearly ''clear blue solution'', which, after it has been diluted with water, can be filtered.) after whom the reagent is named.
copper(II) hydroxide
Copper(II) hydroxide is the hydroxide of copper with the chemical formula of Cu(OH)2. It is a pale greenish blue or bluish green solid. Some forms of copper(II) hydroxide are sold as "stabilized" copper(II) hydroxide, although they likely consist ...
from an aqueous
An aqueous solution is a solution in which the solvent is water. It is mostly shown in chemical equations by appending (aq) to the relevant chemical formula. For example, a solution of table salt, or sodium chloride (NaCl), in water would be re ...
solution of copper sulfate Copper sulfate may refer to:
* Copper(II) sulfate, CuSO4, a common compound used as a fungicide and herbicide
* Copper(I) sulfate
Copper(I) sulfate, also known as cuprous sulfate, is an inorganic compound with the chemical formula Cu2 SO4. It ...
using sodium hydroxide
Sodium hydroxide, also known as lye and caustic soda, is an inorganic compound with the formula NaOH. It is a white solid ionic compound consisting of sodium cations and hydroxide anions .
Sodium hydroxide is a highly caustic base and al ...
or ammonia, then dissolving the precipitate in a solution of ammonia
Ammonia is an inorganic compound of nitrogen and hydrogen with the formula . A stable binary hydride, and the simplest pnictogen hydride, ammonia is a colourless gas with a distinct pungent smell. Biologically, it is a common nitrogenous ...
.
It forms an azure solution. Evaporation of these solutions leaves light blue residue of copper hydroxide, reflecting the lability of the copper-ammonia bonding. If conducted under a stream of ammonia, then deep blue needle-like crystals of the tetrammine form. In presence of oxygen, concentrated solutions give rise to nitrites Cu(NO2)2(NH3)''n''. The nitrite results from oxidation of the ammonia.
Reactions with cellulose
Schweizer's reagent was once used in production ofcellulose
Cellulose is an organic compound with the formula , a polysaccharide consisting of a linear chain of several hundred to many thousands of β(1→4) linked D-glucose units. Cellulose is an important structural component of the primary cell wa ...
products such as rayon
Rayon is a semi-synthetic fiber, made from natural sources of regenerated cellulose, such as wood and related agricultural products. It has the same molecular structure as cellulose. It is also called viscose. Many types and grades of viscose ...
and cellophane (see cupro). Cellulose, which is quite insoluble in water (hence its utility as clothing), dissolves in the presence of Schweizer's reagent. Using the reagent, cellulose can be extracted from wood pulp, cotton fiber, and other natural cellulose sources. Cellulose precipitates when the solution is acidified. It functions by binding to vicinal diol
A diol is a chemical compound containing two hydroxyl groups ( groups). An aliphatic diol is also called a glycol. This pairing of functional groups is pervasive, and many subcategories have been identified.
The most common industrial diol is e ...
s.
Presently, the reagent is used in the analysis of the molecular weight
A molecule is a group of two or more atoms held together by attractive forces known as chemical bonds; depending on context, the term may or may not include ions which satisfy this criterion. In quantum physics, organic chemistry, and bio ...
of cellulose samples.
History
These properties of Schweizer's reagent were discovered by the Swiss chemistMatthias Eduard Schweizer
Matthias Eduard Schweizer (8 August 1818 – 23 October 1860) was a Swiss chemist
who in 1857 invented Schweizer's reagent, in which cellulose can be dissolved to produce artificial silk or rayon.
He was one of the pioneers of the synthetic tex ...
(1818–1860),(Schweizer, 1857), p. 110: ''"Dieselbe besitzt nämlich in ausgezeichnetem Grade das Vermögen, ''bei gewöhnlicher Temperatur Pflanzenfaser aufzulösen.''''Uebergiesst man gereinigte ''Baumwolle'' mit der blauen Flüssigkeit, so nimmt erstere bald eine gallertartige schlüpfrige Beschaffenheit an, die Fasern gehen auseinander und verschwinden und nach einigem Durcharbeiten mit einem Glasstabe hat sich das Ganze in eine schleimige Flüssigkeit verwandelt. Dabei findet nicht die geringste Wärmeentwicklung statt. Hat man nicht eine hinreichende Menge der Flüssigkeit angewendet, so bleibt ein Theil der Fasern noch sichtbar; setzt man dann aber einen Ueberschuss der Lösung hinzu und schüttelt um, so erhält man eine beinahe ''klare blaue Lösung'', die sich, nachdem sie mit Wasser verdünnt worden ist, filtriren lässt."''
(It possesses, namely, to an outstanding degree the capacity ''to dissolve plant fibers at ordinary temperatures.''
If one pours the blue liquid over cleaned ''cotton'', then the former soon assumes a gelatinous, slippery texture, the fibers separate and vanish, and after some kneading with a glass rod, the whole transformed into a slimy liquid. During this, not the least evolution of heat occurred. If one did not use a sufficient quantity of liquid, then a portion of the fibers still remained visible; however, if one then adds an excess of the solution and shakes it, then one obtains a nearly ''clear blue solution'', which, after it has been diluted with water, can be filtered.) after whom the reagent is named.
See also
* Tetraamminecopper(II) sulfateFootnotes
References
* * *{{cite journal , author =George B Kauffman , title = Eduard Schweizer (1818-1860): The Unknown Chemist and His Well-Known Reagent , journal = J. Chem. Educ. , year = 1984 , volume = 61 , issue = 12 , pages = 1095–1097 , doi = 10.1021/ed061p1095, bibcode = 1984JChEd..61.1095K Copper complexes Hydroxides Ammine complexes