Cerium(III) chloride: Difference between revisions

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Simple rapid heating of the hydrate alone may cause small amounts of [[hydrolysis]].<ref name="EdelmannPoremba1997">{{cite book |title=Synthetic Methods of Organometallic and Inorganic Chemistry |volume=VI |last=Edelmann |first=F. T. |author2=Poremba, P. |editor=Herrmann, W. A. |year=1997 |publisher=Georg Thieme Verlag |location=Stuttgart |isbn=3-13-103021-6 }}</ref>
Simple rapid heating of the hydrate alone may cause small amounts of [[hydrolysis]].<ref name="EdelmannPoremba1997">{{cite book |title=Synthetic Methods of Organometallic and Inorganic Chemistry |volume=VI |last=Edelmann |first=F. T. |author2=Poremba, P. |editor=Herrmann, W. A. |year=1997 |publisher=Georg Thieme Verlag |location=Stuttgart |isbn=3-13-103021-6 }}</ref>


A useful form of [[anhydrous]] CeCl<sub>3</sub> can be prepared if care is taken to heat the heptahydrate gradually to {{convert|140|°C|°F|abbr=on}} over many hours under vacuum.<ref name="Paquette1999" /><ref name="JohnsonTait1987">{{cite journal |last=Johnson |first=C. R. |author2=Tait, B. D. |year=1987 |title=A cerium(III) modification of the Peterson reaction: methylenation of readily enolizable carbonyl compounds |journal=Journal of Organic Chemistry |volume=52 |issue=2 |pages=281–283 |issn=0022-3263 |doi=10.1021/jo00378a024 }}</ref><ref name="Dimitrov1996">{{cite journal |last=Dimitrov |first=Vladimir |author2=Kostova, Kalina |author3=Genov, Miroslav  |year=1996 |title=Anhydrous cerium(III) chloride — Effect of the drying process on activity and efficiency |journal=Tetrahedron Letters |volume=37 |issue=37 |pages=6787–6790 |doi=10.1016/S0040-4039(96)01479-7 }}</ref> This may or may not contain a little CeOCl from [[hydrolysis]], but it is suitable for use with [[organolithium reagent|organolithium]] and [[Grignard reagent]]s. Pure anhydrous CeCl<sub>3</sub> can be made by dehydration of the hydrate either by slowly heating to {{convert|400|°C|°F|abbr=on}} with 4–6 equivalents of [[ammonium chloride]] under high vacuum,<ref name="EdelmannPoremba1997" /><ref name="Taylor1962">{{cite journal |last=Taylor |first=M. D. |author2=Carter, P. C. |year=1962 |title=Preparation of anhydrous lanthanide halides, especially iodides |journal=Journal of Inorganic and Nuclear Chemistry |volume=24 |issue=4 |pages=387–391 |doi=10.1016/0022-1902(62)80034-7  }}</ref><ref name="KutscherSchneider1971">{{cite journal |last=Kutscher |first=J. |author2=Schneider, A. |year=1971 |title= Notiz zur Präparation von wasserfreien Lanthaniden-Haloge-niden, Insbesondere von Jodiden|journal=Inorg. Nucl. Chem. Lett. |volume=7 |issue= 9|pages=815 |doi= 10.1016/0020-1650(71)80253-2}}</ref><ref name="Greenwood1984">{{cite book |title=Chemistry of the Elements |last=Greenwood |first=N. N. |author2=Earnshaw, A. |year=1984 |publisher=Pergamon Press |location=New York |isbn=0-08-022056-8 }}</ref> or by heating with an excess of [[thionyl chloride]] for three hours.<ref name="EdelmannPoremba1997" /><ref name="Freeman1958">{{cite journal |last=Freeman |first=J. H. |author2=Smith, M. L. |year=1958 |title=The preparation of anhydrous inorganic chlorides by dehydration with thionyl chloride |journal=Journal of Inorganic and Nuclear Chemistry |volume=7 |issue=3 |pages=224–227 |doi=10.1016/0022-1902(58)80073-1 }}</ref> The anhydrous [[halide]] may alternatively be prepared from [[cerium]] metal and [[hydrogen chloride]].<ref name="Druding1961">{{cite journal |last=Druding |first=L. F. |author2=Corbett, J. D. |year=1961 |title=Lower Oxidation States of the Lanthanides. Neodymium(II) Chloride and Iodide |journal=Journal of the American Chemical Society |volume=83 |issue= 11|pages=2462–2467 |issn=0002-7863 |doi=10.1021/ja01472a010}}</ref><ref name="Corbett1973">{{cite journal |last=Corbett |first=J. D. |year=1973 |title=Reduced Halides of the Rare Earth Elements |journal=Rev. Chim. Minérale |volume=10 |pages=239 }}</ref> It is usually purified by high temperature sublimation under high vacuum. Soxhlet extraction of {{chem2|CeCl3}} with thf gives {{chem2|CeCl3(thf)1.04}}.<ref>{{cite journal |doi=10.1021/acs.organomet.2c00029 |title=Cerium Fluorenyl Complexes Including CC Coupling Reactions |date=2022 |last1=Hirneise |first1=Lars |last2=Buschmann |first2=Dennis A. |last3=Maichle-Mössmer |first3=Cäcilia |last4=Anwander |first4=Reiner |journal=Organometallics |volume=41 |issue=8 |pages=962–976 |s2cid=248065310 }}</ref>
A useful form of [[anhydrous]] CeCl<sub>3</sub> can be prepared if care is taken to heat the heptahydrate gradually to {{convert|140|°C|°F|abbr=on}} over many hours under vacuum.<ref name="Paquette1999" /><ref name="JohnsonTait1987">{{cite journal |last=Johnson |first=C. R. |author2=Tait, B. D. |year=1987 |title=A cerium(III) modification of the Peterson reaction: methylenation of readily enolizable carbonyl compounds |journal=Journal of Organic Chemistry |volume=52 |issue=2 |pages=281–283 |issn=0022-3263 |doi=10.1021/jo00378a024 }}</ref><ref name="Dimitrov1996">{{cite journal |last=Dimitrov |first=Vladimir |author2=Kostova, Kalina |author3=Genov, Miroslav  |year=1996 |title=Anhydrous cerium(III) chloride — Effect of the drying process on activity and efficiency |journal=Tetrahedron Letters |volume=37 |issue=37 |pages=6787–6790 |doi=10.1016/S0040-4039(96)01479-7 }}</ref> This may or may not contain a little CeOCl from [[hydrolysis]], but it is suitable for use with [[organolithium reagent|organolithium]] and [[Grignard reagent]]s. Pure anhydrous CeCl<sub>3</sub> can be made by dehydration of the hydrate either by slowly heating to {{convert|400|°C|°F|abbr=on}} with 4–6 equivalents of [[ammonium chloride]] under high vacuum,<ref name="EdelmannPoremba1997" /><ref name="Taylor1962">{{cite journal |last=Taylor |first=M. D. |author2=Carter, P. C. |year=1962 |title=Preparation of anhydrous lanthanide halides, especially iodides |journal=Journal of Inorganic and Nuclear Chemistry |volume=24 |issue=4 |pages=387–391 |doi=10.1016/0022-1902(62)80034-7  }}</ref><ref name="KutscherSchneider1971">{{cite journal |last=Kutscher |first=J. |author2=Schneider, A. |year=1971 |title= Notiz zur Präparation von wasserfreien Lanthaniden-Haloge-niden, Insbesondere von Jodiden|journal=Inorg. Nucl. Chem. Lett. |volume=7 |issue= 9|pages=815 |doi= 10.1016/0020-1650(71)80253-2}}</ref><ref name="Greenwood1984">{{cite book |title=Chemistry of the Elements |last=Greenwood |first=N. N. |author2=Earnshaw, A. |year=1984 |publisher=Pergamon Press |location=New York |isbn=0-08-022056-8 }}</ref> or by heating with an excess of [[thionyl chloride]] for three hours.<ref name="EdelmannPoremba1997" /><ref name="Freeman1958">{{cite journal |last=Freeman |first=J. H. |author2=Smith, M. L. |year=1958 |title=The preparation of anhydrous inorganic chlorides by dehydration with thionyl chloride |journal=Journal of Inorganic and Nuclear Chemistry |volume=7 |issue=3 |pages=224–227 |doi=10.1016/0022-1902(58)80073-1 }}</ref> The anhydrous [[halide]] may alternatively be prepared from [[cerium]] metal and [[hydrogen chloride]].<ref name="Druding1961">{{cite journal |last=Druding |first=L. F. |author2=Corbett, J. D. |year=1961 |title=Lower Oxidation States of the Lanthanides. Neodymium(II) Chloride and Iodide |journal=Journal of the American Chemical Society |volume=83 |issue= 11|pages=2462–2467 |issn=0002-7863 |doi=10.1021/ja01472a010|bibcode=1961JAChS..83.2462D }}</ref><ref name="Corbett1973">{{cite journal |last=Corbett |first=J. D. |year=1973 |title=Reduced Halides of the Rare Earth Elements |journal=Rev. Chim. Minérale |volume=10 |pages=239 }}</ref> It is usually purified by high temperature sublimation under high vacuum. Soxhlet extraction of {{chem2|CeCl3}} with thf gives {{chem2|CeCl3(thf)1.04}}.<ref>{{cite journal |doi=10.1021/acs.organomet.2c00029 |title=Cerium Fluorenyl Complexes Including CC Coupling Reactions |date=2022 |last1=Hirneise |first1=Lars |last2=Buschmann |first2=Dennis A. |last3=Maichle-Mössmer |first3=Cäcilia |last4=Anwander |first4=Reiner |journal=Organometallics |volume=41 |issue=8 |pages=962–976 |s2cid=248065310 }}</ref>


==Uses==
==Uses==

Latest revision as of 11:00, 1 July 2025

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Cerium(III) chloride (CeCl3), also known as cerous chloride or cerium trichloride, is a compound of cerium and chlorine. It is a white hygroscopic salt; it rapidly absorbs water to form hydrates, which may be of variable composition.The hexa- and heptahydrate CeCl3·7H2O are known.[1] All forms are highly soluble in water, and the anhydrous derivative is soluble in ethanol and acetone.[2][3]

Preparation of anhydrous CeCl3

Simple rapid heating of the hydrate alone may cause small amounts of hydrolysis.[4]

A useful form of anhydrous CeCl3 can be prepared if care is taken to heat the heptahydrate gradually to Template:Convert over many hours under vacuum.[2][5][6] This may or may not contain a little CeOCl from hydrolysis, but it is suitable for use with organolithium and Grignard reagents. Pure anhydrous CeCl3 can be made by dehydration of the hydrate either by slowly heating to Template:Convert with 4–6 equivalents of ammonium chloride under high vacuum,[4][7][8][9] or by heating with an excess of thionyl chloride for three hours.[4][10] The anhydrous halide may alternatively be prepared from cerium metal and hydrogen chloride.[11][12] It is usually purified by high temperature sublimation under high vacuum. Soxhlet extraction of Template:Chem2 with thf gives Template:Chem2.[13]

Uses

Cerium(III) chloride can be used as a starting point for the preparation of other cerium salts, such as the Lewis acid cerium(III) trifluoromethanesulfonate.[14]

Organic synthesis

Cerium(III) chloride is a reagent in several procedures used in organic synthesis.[15] Luche reduction[16] of alpha, beta-unsaturated carbonyl compounds has become a popular method in organic synthesis, where CeCl3·7H2O is used in conjunction with sodium borohydride. For example, carvone gives only the allylic alcohol 1 and none of the saturated alcohol 2. Without CeCl3, a mixture of 1 and 2 is formed.

Luche reduction

It can also deprotect MEM group to alcohol in the presence of other acetal protecting groups (e.g. THP.)

Another important use in organic synthesis is for alkylation of ketones, which would otherwise form enolates if simple organolithium reagents 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: [5]

CeCl3 directed alkylation reaction

It is reported that organolithium reagents work more effectively in this reaction than do Grignard reagents.[5]

References

Template:Reflist

Further reading

  • CRC Handbook of Chemistry and Physics (58th edition), CRC Press, West Palm Beach, Florida, 1977.
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Template:Cerium compounds Template:Chlorides Template:Lanthanide halides

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