Cerium(III) chloride (CeCl₃), also known as cerous chloride or cerium trichloride, is a compound of

cerium Cerium is a chemical element; it has Chemical symbol, symbol Ce and atomic number 58. It is a hardness, soft, ductile, and silvery-white metal that tarnishes when exposed to air. Cerium is the second element in the lanthanide series, and while it ...

and

chlorine Chlorine is a chemical element; it has Symbol (chemistry), symbol Cl and atomic number 17. The second-lightest of the halogens, it appears between fluorine and bromine in the periodic table and its properties are mostly intermediate between ...

. It is a white

hygroscopic Hygroscopy is the phenomenon of attracting and holding water molecules via either absorption (chemistry), absorption or adsorption from the surrounding Natural environment, environment, which is usually at normal or room temperature. If water mol ...

salt; it rapidly absorbs water to form

hydrate In chemistry, a hydrate is a substance that contains water or its constituent elements. The chemical state of the water varies widely between different classes of hydrates, some of which were so labeled before their chemical structure was understo ...

s, which may be of variable composition.The hexa- and heptahydrate CeCl₃·7H₂O are known. All forms are highly soluble in

water Water is an inorganic compound with the chemical formula . It is a transparent, tasteless, odorless, and Color of water, nearly colorless chemical substance. It is the main constituent of Earth's hydrosphere and the fluids of all known liv ...

, and the anhydrous derivative is soluble in

ethanol Ethanol (also called ethyl alcohol, grain alcohol, drinking alcohol, or simply alcohol) is an organic compound with the chemical formula . It is an Alcohol (chemistry), alcohol, with its formula also written as , or EtOH, where Et is the ps ...

and

acetone Acetone (2-propanone or dimethyl ketone) is an organic compound with the chemical formula, formula . It is the simplest and smallest ketone (). It is a colorless, highly Volatile organic compound, volatile, and flammable liquid with a charact ...

Preparation of anhydrous CeCl₃

Simple rapid heating of the hydrate alone may cause small amounts of

hydrolysis Hydrolysis (; ) is any chemical reaction in which a molecule of water breaks one or more chemical bonds. The term is used broadly for substitution reaction, substitution, elimination reaction, elimination, and solvation reactions in which water ...

. A useful form of

anhydrous A substance is anhydrous if it contains no water. Many processes in chemistry can be impeded by the presence of water; therefore, it is important that water-free reagents and techniques are used. In practice, however, it is very difficult to achie ...

CeCl₃ can be prepared if care is taken to heat the heptahydrate gradually to over many hours under vacuum. This may or may not contain a little CeOCl from

, but it is suitable for use with

organolithium In organometallic chemistry, organolithium reagents are chemical compounds that contain carbon–lithium (C–Li) bonds. These reagents are important in organic synthesis, and are frequently used to transfer the organic group or the lithium atom ...

and

Grignard reagent Grignard reagents or Grignard compounds are chemical compounds with the general formula , where X is a halogen and R is an organic group, normally an alkyl or aryl. Two typical examples are methylmagnesium chloride and phenylmagnesium bromi ...

s. Pure anhydrous CeCl₃ can be made by dehydration of the hydrate either by slowly heating to with 4–6 equivalents of

ammonium chloride Ammonium chloride is an inorganic chemical compound with the chemical formula , also written as . It is an ammonium salt of hydrogen chloride. It consists of ammonium cations and chloride anions . It is a white crystalline salt (chemistry), sal ...

under high vacuum, or by heating with an excess of

thionyl chloride Thionyl chloride is an inorganic compound with the chemical formula . It is a moderately Volatility (chemistry), volatile, colourless liquid with an unpleasant acrid odour. Thionyl chloride is primarily used as a Halogenation, chlorinating reagen ...

for three hours. The anhydrous

halide In chemistry, a halide (rarely halogenide) is a binary chemical compound, of which one part is a halogen atom and the other part is an element or radical that is less electronegative (or more electropositive) than the halogen, to make a fl ...

may alternatively be prepared from

metal and

hydrogen chloride The Chemical compound, compound hydrogen chloride has the chemical formula and as such is a hydrogen halide. At room temperature, it is a colorless gas, which forms white fumes of hydrochloric acid upon contact with atmospheric water vapor. Hyd ...

. It is usually purified by high temperature sublimation under high vacuum. Soxhlet extraction of with thf gives .

Uses

Cerium(III) chloride can be used as a starting point for the preparation of other

salt In common usage, salt is a mineral composed primarily of sodium chloride (NaCl). When used in food, especially in granulated form, it is more formally called table salt. In the form of a natural crystalline mineral, salt is also known as r ...

s, such as the

Lewis acid A Lewis acid (named for the American physical chemist Gilbert N. Lewis) is a chemical species that contains an empty orbital which is capable of accepting an electron pair from a Lewis base to form a Lewis adduct. A Lewis base, then, is any ...

cerium(III) trifluoromethanesulfonate Lanthanide triflates are triflate salts of the lanthanides. These salts have been investigated for application in organic synthesis as Lewis acid catalysts. These catalysts function similarly to aluminium chloride or ferric chloride, but they are ...

Organic synthesis

Cerium(III) chloride is a reagent in several procedures used in organic synthesis.

Luche reduction Luche reduction is the selective organic redox reaction, organic reduction of Alpha-beta Unsaturated carbonyl compounds, α,β-unsaturated ketones to allyl alcohol, allylic alcohols. The active reductant is described as "cerium borohydride", whic ...

of alpha, beta-unsaturated carbonyl compounds has become a popular method in

organic synthesis Organic synthesis is a branch of chemical synthesis concerned with the construction of organic compounds. Organic compounds are molecules consisting of combinations of covalently-linked hydrogen, carbon, oxygen, and nitrogen atoms. Within the gen ...

, where CeCl₃·7H₂O is used in conjunction with

sodium borohydride Sodium borohydride, also known as sodium tetrahydridoborate and sodium tetrahydroborate, is an inorganic compound with the formula (sometimes written as ). It is a white crystalline solid, usually encountered as an aqueous basic solution. Sodi ...

. For example,

carvone Carvone is a member of a family of chemicals called terpenoids. Carvone is found naturally in many essential oils, but is most abundant in the oils from seeds of caraway (''Carum carvi''), spearmint (''Mentha spicata''), and dill. Uses Food appli ...

gives only the allylic

alcohol Alcohol may refer to: Common uses * Alcohol (chemistry), a class of compounds * Ethanol, one of several alcohols, commonly known as alcohol in everyday life ** Alcohol (drug), intoxicant found in alcoholic beverages ** Alcoholic beverage, an alco ...

1 and none of the saturated

2. Without CeCl₃, a mixture of 1 and 2 is formed. It can also deprotect

MEM Mem (also spelled Meem, Meme, or Mim) is the thirteenth letter of the Semitic abjads, including Hebrew ''mēm'' , Aramaic ''mem'' 𐡌, Syriac ''mīm'' ܡ, Arabic ''mīm'' , and Phoenician ''mēm'' 𐤌. Its sound value is . It is also relate ...

group to alcohol in the presence of other acetal protecting groups (e.g. THP.) Another important use in

is for alkylation of

ketone In organic chemistry, a ketone is an organic compound with the structure , where R and R' can be a variety of carbon-containing substituents. Ketones contain a carbonyl group (a carbon-oxygen double bond C=O). The simplest ketone is acetone ( ...

s, which would otherwise form

enolate In organic chemistry, enolates are organic anions derived from the deprotonation of carbonyl () compounds. Rarely isolated, they are widely used as reagents in the Organic synthesis, synthesis of organic compounds. Bonding and structure Enolate ...

s if simple

organolithium reagent In organometallic chemistry, organolithium reagents are chemical compounds that contain carbon–lithium (C–Li) bonds. These reagents are important in organic synthesis, and are frequently used to transfer the organic group or the lithium atom ...

s were to be used. For example, compound 3 would be expected to simply form an enolate without CeCl₃ being present, but in the presence of CeCl₃ smooth alkylation occurs: Cerium alkylation

It is reported that organolithium reagents work more effectively in this reaction than do

Preparation of anhydrous CeCl₃

Uses

Organic synthesis

References

Further reading

Preparation of anhydrous CeCl3

Uses

Organic synthesis

References

Further reading

Preparation of anhydrous CeCl₃