Page:Encyclopædia Britannica, Ninth Edition, v. 5.djvu/585

Rh ORGANO-METALLIC BODIES.] CHEMISTRY 573 (Rubia tinctoria) is alizarin (C 14 H S O 4 ), which exists in the root as a glucoside (rubianic acid) (C 26 H 28 O 14 ). When heatsd with zinc dust alizarin yields anthracene (C 14 H 10 ), and conversely, anthracene can be converted into alizarin by first oxidizing it to anthraquinone (C 14 H 8 O 2 &quot;), then by treatment with Br or H 2 S0 4 transforming the quinone into dibromanthraquinone or anthraquinone-disulphonic acid, and finally fusing either of these products with caustic alkalies : C 14 H 6 Br 2 O 2 &quot; + 2KHO - C 14 H 8 O 4 + 2KBr. Large quantities of artificial alizarin are thus manufactured. Vanillin (C 8 H 8 O 3 ), the odorous principle of vanilla, has also been obtained artificially from conifer in (C 16 H 22 O 8 ), a glucoside obtained from the cambium of Coniferous trees. This glucoside when heated with water and emulsin is resolved into glucose and a crystalline substance (C 10 H 12 O 3 ) which on oxidation is converted into vanillin. By the action of sodium on ethyl acetate there is pro duced among other compounds the sodium salt of an acid, C 6 H 10 O 3, which is of extreme interest on account of .its enabling the ascent of the series of ketones and fatty acids to be effected. Thus : Ascent ( of Ketones H 2 (C n H 2n+1 ) + 1 1 6 C 2 H 5 ?Hb+~K 2 C0 3 . The ascent of the fatty acids is more simply explained by considering the first products of the action of Na on ethyl acetate to result from the replacement of the methyl hydrogen by Na. Thus: / CH 2 Na ^ p T _ / CH,(C n H OB+1 ) ^ &quot; 2 &quot; +1 }CO(OC 2 H 5 ) Ethyl monosodacetate. New ethereal salt. CHXa 2 ( CH(C n H 2n+1 ) 2 /wu 2+i 1 ~ CO(OC 2 H 5 ) Ethyl disodacetate. New ethereal salt. The liberation of the acid from the ethereal salt is effected by the action of KHO, as previously explained. XII. OKGAXO-METALLIC BODIES. The constitution of these compounds has been already considered (p. 553) ; they have to be distinguished from organic compounds containing metals, such as metallic salts of organic acids. In organo-metallic bodies the metal is directly combined with the hydrocarbon radicle, while in organic compounds containing metals the metallic atom is connected with the radicle through the medium of some other element: H 2 H 2 O O H 3 C C Zn CH 3 Zinc ethide. H 3 C C O Zn C CH 3 Zinc acetate. Organo-zinc compounds are prepared by the action of zinc upon the iodides of C n H 0n+1 radicles : 2Zn + 2C n H 2rt+1 I = Zn(C n H 2n+1 ) 2 + ZnI 2. The operation is most rapidly conducted by digesting the iodide with zinc foil coated with copper by previous immersion in a weak solution of cupric sulphate (Glad stone and Tribe). Zinc ethide, the first of these compounds obtained by Frankland, is a limpid, mobile liquid boiling at 118 C., and spontaneously inflammable. Organo-compounds of tin, lead, mercury, bismuth, arsenic, and antimony have been prepared by the action of the iodides and bromides of the corresponding radicles on the potassium or sodium alloys of the metals : HgXa, + C 2 H 5 I = Hg(C 2 H 5 ) 2 + Nal Sodium amalgam. Ethyl iodide. Mercuric ethide. HgNa 2 + 2C 6 H 5 Br = Hg(C a H 5 ) 2 + 2NaBr. Sodium amalgam. Phenyl bromide. Mercuric phenide. 1 By the action of nascent hydrogen these compounds are converted into ethereal salts of secondary define acids of the lactic series (p. 570). Many organo-metallic bodies are derived from others by simple replacement or by double decomposition : SnCl 4 + 2Zn(C 2 H 5 ) 2 = Sn(C 2 H 6 ) 4 + 2ZnCl 2 Stannic chloride. Zinc ethide. Stannic ethide. 3Hg(C 2 H 5 ) 2 + A1 2 = A1 2 (C 2 H 5 ) 6 + 3Hg Mercuric ethide. Aluminic ethide. 3Zn(C 2 H 5 ) 2 + Na 2 = 2[Na(C 2 H 5 ), Zn(C 2 H 5 ) 2 ] + Zn. Zinc ethide. Sodic zinc ethide. In the case of organo-compounds of monad metals pre pared by the direct action of the metal on some other body, as in the last reaction, the original compound occurs inseparably in the resulting compound. The following is a list of the organo-metallic bodies : Potassic zinc methide .............. K(CH 3 ), Zn(CH 3 ) 2 Potassiczinc ethide ................ K(C 2 H 5 ), Zn(C 2 H 5 ) z Sodic zinc ethide .................... Na(C 2 H 5 ), Zn(C 2 H 5 ) 2 Lithic zinc ethide ................... Li(C 2 H 5 ), Zn(C 2 H 5 ) 2 Lithic mercuric ethide ............. Li(C 2 H 5 ), Hg(C a H 5 ) r. Magnesium ethide ................. Mg(C 2 H 5 ) 2 Zinc methide ........................ Zn(CH 3 ) 2 Zinc ethide ........................... Zn(C 2 H 5 ) 2 Zinc propide ......................... Zn(C 3 H 7 ) 2 Zinc amylide ........................ Zu(C 5 H u ) 2 Aluminium methide ............... A1.,(CH 3 ) 8 Aluminium ethide .................. A1 2 ( 2 H 5 ) 8 Aluminium propide ................. A1. 2 (C 3 H 7 ) 8 Glucinum propide ................ G(C 3 H 7 ) 2 Mercuric methide ................... Hg(CH 3 ) 2 Mercuric ethide ..................... Hg(C 2 H 5 )j Mercuric propide .................... Hg(C 3 H 7 ). 2 Mercuric amylide ................... Hgt C 5 H n ) 2 Mercuric phenide ................... Hg(C 6 H 5 ) 2 Mercuric tolylide ................... Hg(C 7 H 7 ) 2 Mercuric naphtliide ................ Hg(C 10 H 7 ) 2 Stannous ethide ..................... Sn. 2 (C 2 H 5 ) 2 Distannic hexethide ................ Sn 2 (C 2 H 5 ) 8 Stannic methide .................... Sn(CH 3 ) 4 Stannic ethide ....................... Sn(C 2 H 5 ) 4 Stannic diethodimethide ......... Sn(C 2 H 5 ). 2 (CH 3 ) Z Stannic phenyltriethide ........... Sn(C 6 H 8 )(GH 3 ) 3 Stannic iodotripropide ............ Sn (C 3 H 7 ) 3 I Plumbic ethide ...................... Pb(C 2 H 5 ) 4 Not many isomerides of the above compounds have as yet been obtained ; zinc pseudopropide and mercuric lenzy- lide (isomeric with the tolylide) are known. The extreme readiness with which the organo-metallic bodies exchange their hydrocarbon radicles for more nega tive elements or radicles obviously renders them of parti cular value in organic synthesis. The following are further important reactions : 1. Synthesis of fatty acids by the direct absorption of CO 2 by organo-sodium compounds : 2. Displacement of halogens, oxygen, (HO), (OC,,H 2n+1 ), &c., by CJ3 0n+1 radicles (see the preparation of Sn(C 2 H 5 ) 4 from SnCl 4 given above) : Ethyl oxalate. Zn Ethyl diethoxalate. + C 2 H 5 .HO. Zinc ethide. OH OH Zinc hydroxide. Alcohol. Also, formation of paraffins by action of water on organo- zinc bodies : Zn(C n H 2;i+1 ) 2 + 20H 2 = Zn(HO) 2 + 2C n H 2n+2. Compounds intermediate between organo-metallic bodies and haloid salts of tke metals have been obtained, e.g. Hg(CH 3 )I, Sn(CH 3 ) 2 I 2 , Sn 2 (C 2 H 6 ) 4 I 2 , Mercuric methiodide. Stannic dimetho-diiodide. Distannic tetretho-diiodide. Sn(C 6 H 5 )(C 2 H,)Cl 2. Stannic etho-phenyl-dichloride.