Ammonium cerium (IV) nitrate

from Wikipedia, the free encyclopedia
Structural formula
2 · Ammonium ion   Structural formula of the hexanitratocerate anion
Crystal system

monoclinic

Space group

P 2 1 / n (No. 14, position 2)Template: room group / 14.2

Lattice parameters

a = 1306.1 ± 0.7 pm,
b = 684.2 ± 0.4 pm,
c = 818.3 ± 0.4 pm,
β = 91.34 ± 0.02 °,
Z = 2

General
Surname Ammonium cerium (IV) nitrate
other names
  • Cerium (IV) ammonium nitrate
  • CAN
  • Cerium (IV) ammonium nitrate
  • Ammonium hexanitratocerate (IV)
  • Diammonium hexanitratocerate (IV)
Molecular formula (NH 4 ) 2 [Ce (NO 3 ) 6 ]
Brief description

orange solid

External identifiers / databases
CAS number 16774-21-3
EC number 240-827-6
ECHA InfoCard 100.037.100
PubChem 16211559
Wikidata Q417928
properties
Molar mass 548.26 g mol −1
Physical state

Solid

density

2.490 g cm −3

Melting point

108 ° C

solubility
  • easily in water (1410 g l −1 at 20 ° C)
  • insoluble in chloroform
safety instructions
GHS labeling of hazardous substances
03 - Oxidising 05 - Corrosive 07 - Warning

danger

H and P phrases H: 272-302-314
P: 221-280-301 + 330 + 331-305 + 351 + 338-308 + 310
Toxicological data

300–2000 mg kg −1 ( LD 50 ,  rat ,  oral )

As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions .

Ammonium cer (IV) nitrate (also cerium (IV) ammonium nitrate , abbreviated CAN ) is an inorganic compound with the formula (NH 4 ) 2 [Ce (NO 3 ) 6 ]. It is an orange-red crystalline solid and is readily soluble in water. The compound is used as an oxidizing agent in organic synthesis and in quantitative analysis ( oxidimetry ).

presentation

powdery sample

The anionic complex [Ce (NO 3 ) 6 ] 2− is produced by the conversion of Ce 3+ ions e.g. B. obtained by oxidation with boiling nitric acid . In the presence of ammonium nitrate , ammonium cerium (IV) nitrate is formed. The ammonium cation is not involved in the oxidation processes of ammonium cerium (IV) nitrate.

properties

Ce 4+ is a strong oxidizing reagent (E ° ~ 1.61 V against the normal hydrogen electrode ) and is even stronger than elemental chlorine (E ° ~ 1.36 V). During the redox reaction, Ce (IV) is reduced to Ce (III) by a one-electron transfer and the color of the aqueous solution changes from orange to a pale yellow color (provided, of course, that the reactants have no inherent color).

use

Oxidizing agent

Ammonium cerium (IV) nitrate is a frequently used oxidizing agent for the oxidation of various functional groups. These include alcohols , phenols and ethers . C – H bonds can also e.g. B. be oxidized in benzyl positions . The oxidation of catechols and hydroquinones yield the corresponding quinones .

Protecting chemistry

In protecting group chemistry, ammonium cerium (IV) nitrate is used for the cleavage of p- methoxy and 3,4-dimethoxybenzyl ethers. The aromatic is split off from the protected alcohol via a quinomethine intermediate.

Deprotection of p-methoxybenzyl ether and 3,4-dimethoxybenzyl ether

The reaction mechanism is believed to be the same as that for deprotection with DDQ as the oxidant. The oxidizing agent (CAN or DDQ) is reduced by absorbing a total of two electrons (two CAN molecules are involved in CAN) and the benzyl ether reacts to form the corresponding aldehyde with oxidation and water attachment.

Deprotection of p-methoxybenzyl ether (mechanism)

Etching of chrome

When structuring thin films , ammonium cerium (IV) nitrate is used for the selective etching of chromium . The chromium is oxidized by the cerium and thus brought into solution. A solution of approx. 10% ammonium cerium (IV) nitrate in an acid ( nitric , perchloric or acetic acid ) has an etching rate of approx. 50–150 nm / min.

Individual evidence

  1. ^ A b c d Thomas A. Beinke, J. Delgaudio: Crystal structure of ceric ammonium nitrate . In: Inorganic Chemistry . tape 7 , no. 4 , 1968, p. 715-721 , doi : 10.1021 / ic50062a020 .
  2. ↑ Preetam Singh, MS Hegde: Controlled synthesis of nanocrystalline CeO 2 and Ce 1 - x M x O 2 −δ (M = Zr, Y, Ti, Pr and Fe) solid solutions by the hydrothermal method: Structure and oxygen storage capacity . In: Journal of Solid State Chemistry . tape 181 , no. 12 , 2008, p. 3248-3256 , doi : 10.1016 / j.jssc.2008.08.018 .
  3. ↑ a b c data sheet ammonium cerium (IV) nitrate (PDF) from Merck , accessed on January 3, 2012.
  4. ↑ Veli T. Kasumov, Ali ©. Öztürk, Fevzi Köksal: Synthesis, characterization and redox behavior of bis (N-1-adamantanyl- and N-2-adamantanyl-3,5-tBu2-salicylaldiminato) copper (II) complexes . In: Polyhedron . tape 26 , no. 13 , 2007, p. 3129-3135 , doi : 10.1016 / j.poly.2007.02.012 .
  5. ↑ a b Entry on diammonium hexanitratocerate in the GESTIS substance database of the IFA , accessed on January 10, 2017(JavaScript required) .
  6. ↑ G. Brauer: Handbook of Preparative Inorganic Chemistry , Vol. 2, Academic, New York 1965.
  7. ↑ Vijay Nair, Lakshmi Balagopal, Roshini Rajan, Jessy Mathew, "Recent Advances in Synthetic Transformations Mediated by Cerium (IV) Ammonium Nitrate", in: Acc. Chem. Res. , (2004), 37, pp. 21-30 ( doi : 10.1021 / ar030002z ).
  8. ↑ Vijay Nair, Sreeletha B. Panicker, Latha G. Nair, Tesmol G. George, Anu Augustine: "Carbon-Heteroatom Bond-Forming Reactions Mediated by Cerium (IV) Ammonium Nitrate: An Overview", in: Synlett , (2003) , Pp. 156-165 ( doi : 10.1055 / s-2003-36775 ).
  9. ↑ Phillip J. Kocienski: Protecting Groups , 1st edition, Georg Thieme Verlag, Stuttgart 1994, ISBN 3-13-135601-4 .
  10. ↑ Microchemicals: Etching of Chromium ( PDF ).

Web links