Volume 1

Watts' dictionary of chemistry / revised and entirely rewritten by H. Forster Morley and M.M. Pattison Muir ; assisted by eminent contributors.

Date:: 1888-1894

Credit: Watts' dictionary of chemistry / revised and entirely rewritten by H. Forster Morley and M.M. Pattison Muir ; assisted by eminent contributors. Source: Wellcome Collection.

Provider: This material has been provided by the Royal College of Physicians of Edinburgh. The original may be consulted at the Royal College of Physicians of Edinburgh.

749/796 (page 723)

$little on cooling, but cerebrin mixed with eholes- terin separates from the subsequent extracts. The cholesterin is removed by solution in ether. So prepared, cerebrin is free from phosphorus but contains inorganic matter. 250 grms. were got from 90 brains. It is redissolved in alcohol at 60° which leaves a barium salt undissolved. The barium that goes into solution is removed by a current of CO.,. The cerebrin is purified by frequent recrystallisations from alcohol. The earlier mother-liquors deposit on standing a gelatinous pp. By recrystallisation from alcohol this pp. may be separated into cerebrin (spheri- cal crystals), homocerebrin (needles), and en- cephalin (E. Parous, J. pr. 132, 310). Properties.—Separates as a white crystalline powder composed of transparent globules from a boiling alcoholic solution. Soluble in acetone, chloroform, benzene, and glacial acetic acid. Insoluble in ether. Separates from acetone partly as globules, partly as matted threads. Cerebrin dissolves in cone. ELS04. On standing exposed to the air, the liquid becomes covered with a purple skin, which afterwards turns green. Cerebrin does not combine with acids, bases, or salts. It is not affected by boiling for a short time with baryta. It is but slightly decomposed by boiling alcoholic potash. Cerebrin swells up but slightly in boiling water. It is very slightly hygroscopic, absorbing 2 p.c. of water from the air. It is decomposed by boiling for a long time with baryta. Boiled for some hours with dilute HC1 it forms a solution that can reduce Fehling's solution. Homocerebrin C. 70'1 p.c.; H. 116; N. 2 2 ; O. 16-1. The yield is \ that of the cerebrin. Soluble in the same liquids as cerebrin ; soluble also in boiling ether. Swells up in hot water, but does not form a paste. Is not decomposed by boiling water. Treated with hot HC1, it forms a solution that reduces Fehling's solution. Boiled for a long time with baryta, it is decom- posed. It is not hygroscopic. Its solutions are neutral. It does not combine with acids, bases, or salts. It separates from alcoholic solutions in very fine needles. After separation from alcohol and drying, it is not a white powder (like cerebrin) but a waxy mass. It is more soluble in absolute alcohol than cerebrin. Encephalin. C. 68-4; H. 11-6; N. 3-1; 0.16-9. Resembles homocerebrin rather than cerebrin. It separates from solutions in flexible plates. From acetone it separates in granular masses. It - swells up with hot water forming a complete paste. Boiled with HC1, it forms a solution that can reduce Fehling's solution. CEKIC ACID. C. 64-2p.c; H.8-8 p.c.; O. 27 0 p.c. Obtained by the action of HN03 on cerin, or according to Kiigler on phellonic acid C22H4203 [96°]. Phellonic acid is obtained, together with glycerin and stearic acid, by the action of alco- holic KHO on cork that has previously been exhausted by chloroform and alcohol (Dopping, A. 45, 289). CERIN C,„H320(?). [250°]. A substance that may be extracted by chloroform from cork, the bark of Qucrcus Suber, in which it occurs to the extent of 2 p.c. (Kiigler, Ar. Ph. [3] 22,217; cf. Chevreul, A. Ch. 96, 170; Dopping, A. 45, 289). Needles, insol. water, sol. other solvents. According to Siewert (Z. 1868,383) an alcoholic extract of cork contains phellyl alcohol C^H.^O [100°], a neutral, crystalline substance, si. sol. alcohol. CERIUM. Ce. At. w. 139-9. Mol. w. un- known as element has not been gasified. S.G. (abt. 18°) 6-63 to 6-73 (Hillebrand a. Norton, P. 156, 471). M.P. considerably above that of Sb (450°) but below that of Ag (950°) (H. a. N.). S.H. (0°-100°) -04479 (H., P. 158, 7). S.V.S. 21-1. Chief lines in emission-spectrum ; 5352-2, 5273-2, 4628-2, 4572-6, 4562-1, 4296, 4289 (Tha- len). In 1803 Klaproth, and independently Berzelius and Hisinger, separated a new earth from a Swedish mineral and called it Ceria (from the then recently discovered planet Ceres); in 1839-41 Mosander (P. 11, 406) proved that ceria was a mixture of at least three metallic oxides, oxides viz. of Ce, La, and Di. The metal cerium was first obtained by Mosander in 1826, it was more fully examined by Wohler, Bunsen; and other chemists. Occurrence.—In many Swedish minerals, more especially in cerite a silicate of Ce (abt. 56 p.c. Ce20.i); occurs as silicate, phosphate, carbonate, fluoride, &c, also in many apatites ; generally accompanied by La, Di, Fe, Al, &c. It has been recently found that clay used for brickmaking at Hanistadt (near Seeligenstadt in the neighbourhood of Frankfurt) contains from 8 to 12 p.c. of Ce.,Oa (Strohecker, J. pr. [2] 33, 133 a. 260). Preparation.—Cerite is heated to redness, powdered, mixed with considerable excess of cone. H2S04, and the mixture is gradually heated to incipient redness in a Hessian crucible; after cooling, the mass is powdered and then added, little by little, to ice-cold water, whereby sul- phates of Ce, La, and Di are dissolved; the treatment with H2S04 &c. is repeated with the portion insoluble in cold water ; the aqueous solution is heated to boiling, whereby basic sul- phates are ppd.; solution in ice-cold water and ppn. by heating to boiling are repeated several times (Marignac; Bunsen ; Wohler). The solu- tion in cold water is ppd. by addition of oxalic acid solution; the oxalates are washed with water, dried, and heated in a Pt dish until com- pletely converted into oxides. The mixed oxides (of Ce, La, and Di) may now be treated in many different ways. The following method was used by Brauner (C. J. 47, 884) in order to prepare pure Ce23SO, for atomic weight determinations; it is based upon the formation of basic Ce nitrate insoluble in water. The mixed oxides were dissolved in moderately cone. HNOAq, excess of acid was removed by evaporation, and the syrup-like liquid was poured into much pure boiling water; the ppd. basic eerie nitrate was washed (on a funnel connected with a pump) with boiling water containing a little nitric acid. The nitrate was dissolved in HNO.,Aq, excess of acid was removed by evaporation, the liquid was poured into boiling water, &c, as already described. This treatment was repeated 10 or 11 times. From the pure basic eerie nitrate thus obtained other Ce compounds may be pre- pared. Brauner prepared Ce.^SO., by dissolving the basic nitrate in diluteH._,S01Aq,andH,SO:iAq, evaporating to dryness in a Pt dish, and heating with due precaution, dissolving in a little ice- cold water, ppg. by absolute alcohol, washing 3 a 2$