Ceric ammonium nitrate
Monoclinic
P21 / n
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
- Cerium (IV ) ammonium nitrate
- CAN
Orange solid
Solid fuel
2.490 g · cm -3
108 ° C.
- Soluble in water (1410 g · l-1 at 20 ° C)
- Insoluble in chloroform
Risk
300-2000 mg · kg -1 ( LD50, rat, oral)
Template: Infobox chemical / molecular formula search available
Cerium ( IV ) ammonium nitrate (hereinafter abbreviated CAN) is an inorganic compound with the molecular formula (NH4) 2Ce (NO3 ) 6 CAN 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 the quantitative analysis ( Oxidimetrie ).
Representation
The anion [ Ce ( NO3 ) 6] 2 - is obtained by the reaction of cerium (III ) oxide ( Ce.sub.2O.sub.3 ) by oxidation with boiling nitric acid. In the presence of ammonium nitrate CAN is obtained. The ammonium cation is not involved in the oxidation processes of the CAN.
Application in Organic Chemistry
Ce4 is a strong oxidizing reagent ( E ° ~ 1.61 V versus the standard hydrogen electrode) and is even stronger than elemental chlorine (E ° ~ 1.36 V). During the redox reaction of Ce ( IV) is reduced by one-electron transfer to the Ce ( III), and the color of the aqueous solution changes from orange to a pale yellow color ( provided, of course, that the reaction partners do not have any intrinsic color ).
CAN is a frequently used oxidizing agent for the oxidation of a variety of functional groups. These include alcohols, phenols and ethers. Also C -H bonds can be oxidized in Benzylstellungen eg. The oxidation of catechols and hydroquinones give the corresponding quinones.
Protecting group chemistry
In the protection group chemistry CAN finds application in the columns of p-methoxy- and 3,4- dimethoxybenzyl - ethers. Here, the aromatic compound is cleaved by a Chinomethin intermediate from the protected alcohol.
The reaction mechanism is probably the same as in the deprotection with DDQ as an oxidant. The oxidizing agent (CAN or DDQ) is determined by the recording of a total of two electrons ( with the CAN, two molecules involved CAN ) is reduced and the benzyl ether reacts with oxidation and hydration to the corresponding aldehyde.
Etching of chromium
In the structuring of thin films CAN is used for selective etching of chromium. Here, the chromium is oxidized by the CE and thereby dissolved. A solution of approximately 10% CAN in an acid ( nitric acid, perchloric acid or acetic acid ) has an etch rate of about 50-150 nm / min.