ISBN: 9781156212721

Purchase includes free access to book updates online and a free trial membership in the publisher's book club where you can select from more than a million books without charge. Excerpt: … Altro …

Purchase includes free access to book updates online and a free trial membership in the publisher's book club where you can select from more than a million books without charge. Excerpt: 817 °C (anhydrous)90 °C (heptahydrate, decomp) Cerium(III) chloride (CeCl3), also known as cerous chloride or cerium trichloride, is a compound of cerium and chlorine. It is a white hygroscopic solid; It rapidly absorbs water on exposure to moist air to form a hydrate which appears to be of Purchase includes free access to book updates online and a free trial membership in the publisher's book club where you can select from more than a million books without charge. Excerpt: 817 °C (anhydrous)90 °C (heptahydrate, decomp) Cerium(III) chloride (CeCl3), also known as cerous chloride or cerium trichloride, is a compound of cerium and chlorine. It is a white hygroscopic solid; It rapidly absorbs water on exposure to moist air to form a hydrate which appears to be of variable composition, though the heptahydrate CeCl3.7 H2O is known. It is highly soluble in water, and (when anhydrous) it is soluble in ethanol and acetone. Simple rapid heating of the hydrate alone may cause small amounts of hydrolysis. A useful form of anhydrous CeCl3 can be prepared if care is taken to heat the heptahydrate gradually to 140 °C (284 °F) over many hours under vacuum. 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 400 °C (752 °F) with 4-6 equivalents of ammonium chloride under high vacuum, or by heating with an excess of thionyl chloride for three hours. The anhydrous halide may alternatively be prepared from cerium metal and hydrogen chloride. It is usually purified by high temperature sublimation under high vacuum. 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, used for Friedel-Crafts acylations. It is also used itself as a Lewis acid, for example as a catalyst in Friedel-Crafts alkylation reactions. Luche reduction 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 alc. Books, , Cerium-Compounds~~Books-LLC, , , , , , , , , , General Books LLC<