ACTION OF CALCIUM AND LITHIUM ON ORGANIC HALIDES. 385XLIIL-Tlie Action of Calcium and Lithium on OrganicHalides.By JAMES FREDERICK SPENCER and GWYNNEDD MARY PRICE.IN a previous paper (Spencer and Wallace, Trans., 1908, 93, 1827)mention was made of a preliminary experiment in which lithiumreacted with a-bromonaphthalene with the formation of naph-thalene. The present communication describes a series of experi-ments in which the action of calcium and lithium on organichalogen derivatives has been studied. Lithium reacts with a largenumber of organic halogen derivatives when the two substancesare heated together. I n many cases this reaction takes place atthe boiling point of the organic compound, but with some sub-stances, notably methyl iodide and bromobenzene, higher tem-peratures are required, which necessitate the use of sealed tubes.With isopropyl iodide and methyl y-bromobenzoate, no reactiontook place.The reaction may be regarded as proceeding in the two directionsindicated by the equations :1.RX + 2Li =RLi + LiX.2. 2RX + 2Li = R-R t 2LiX.The products obtained in some cases showed that the reactionhad proceeded according t o equation 1, for example, those obtaine386 SPENCER AND PRICE: THE AC!I’ION OFfrom p-bromotoluene, pchlorophenol, pchloroaniline, and p-bromo-acetanilide, whilst in other cases the products indicated that thereaction had taken place in both directions. None of the reactionsinvestigated proceeded along the direction indicated by the secondequation alone.I n all cases white, deliquescent compounds wereformed, which reacted with water with the evolution of heat andthe formation of the parent substance of the halogen derivativeemployed. The reaction with water can be represented by theequation :LiR + H,O = LiOH + RH.The white, deliquescent compounds obtained, on the basis of theabove equations, consist of mixtures of lithium halide and thelithium derivative of the hydrocarbon. It has been found prac-tically impossible to separate these two substances owing to theease with which the lithio-hydrocarbon is decomposed by solventsand the atmospheric moisture, but an analysis was made of thewhole solid product in the case of the reaction between propyliodide and lithium, and the results point to the presence of lithio-propane.The yield of the product in these reactions varies considerably,from about 80 per cent.of the theoretical in the case of mchloro-aniline to about‘ 8 per cent. in the case of octyl iodide, but generallythey are good.The reaction products, in all experiments where anilinederivatives were employed, had a strong odour of carbylamine,but this substance was not present in quantity large enough to beisolated. The reaction products in the case of pbromoacetanilidecontained much aniline, which is attributed to the hydrolysis of theoriginal product, acetanilide, by the lithium hydroxide during thesteam distillation.The reaction between iodobenzene and lithium was also tried inabsolute ether solution under the usual Grignard conditions. Nocompound other than diphenyl and lithium iodide could be isolatedfrom the reaction products, so that it may be taken that lithiumand halogen derivatives in ether solution react according to theWurtz reaction and not according to the Grignard reaction.Calcium did not react very readily with organic halides, and inthose cases where reaction did occur, the products rarely exceeded40 per cent.of the theoretical amount. The reaction may beregarded as taking place along two lines, analogous to those of thecorresponding reactions with lithium and magnesium (Trans., 1908,93, 69):1. Ca + RX = R*CaX.2. Ca + 2RX = CaX, + R*RCAT,Cl'IJhf AND LI'THlUM ON ORGANIC HALIDES, 387I n many cases, although indication of a reaction wits given onheating the two substances at the boiling point of the organichalide, it was necessary to employ higher temperatures and pressureto cause the action to proceed to any large extent, and in all suchcases a considerable quantity of gas was evolved on opening thesealed tubes.The gases evolved consisted of hydrogen and bothsaturated and unsaturated open-chain hydrocarbons. The solidproducts were generally white, crystalline, deliquescent substancesof the formula RCaX, which were coloured brown by the productsof the pyrogenic decomposition of the organic halide.The products from the reactions with aniline derivatives alwayshad a strong odour of carbylamine, but this substance was notpresent in sufficient quantity to be isolated.The intermediatecompounds of the formula RCaX were extremely difficult to isolate,but in the case of p-chlorophenol it wits found possible to isolateand analyse the derivative, which agreed well with the formulaOH*C,H,*CaCl.E. Beckmann (Ber., 1905, 38, 905) states that ethyl iodide andcalcium react very readily in ethereal solution, with the formationof the compound C,H,*CaI-O(C,H,),, the whole reaction beingcomplete in a few minutes. We have repeated this reaction andalso the reaction with iodobenzene under similar conditions, andhave obtained in both cases products of the type It*CaI*O(C2€15)2,but the reaction took place very slowly, requiring about twentyhours for completion. The addition of a trace of iodine acceleratedit somewhat, but even then it was much slower than indicated byB ec kmann .Metallic calcium, even in inorgznic reactions, is difficult tomanipulate owing t o the insolubility of its derivatives, whichgenerally coat the metal, and thereby stop or greatly impede thereaction.This probably, in addition to a possible superficial coatingof oxide on the metal employed, may be the reason for the difficultyexperienced in these experiments, and may also explain the pooryields obtained.EXP ERI MENTAL.I n the experiments with lithium, the metal was cut into smallpieces under ether, then quickly dried with filter paper, and addedto the organic halide. Equimolecular quantities of the metal andhalide were used in all cases. The reactions with all the substancestried, except bromobenzene and methyl iodide, took place whenheated in a quartz flask, fitted with a condenser, a t the boilingpoint of the halide for periods varying from three to twenty hours.The reaction products were in all cases white, crystalline,deliquescent solids, which decomposed on the addition of waterVOL.XCVII. D 388 ACTION OF CALCIUM AND LITHIUM ON ORGANIC HALIDES.with the evolution of heat. The products, after treatment withwater, were distilled in a current of steam, and the distillate andthe residue in the distilling flask investigated. The results, togetherwith the yields of the products, are given in the table below. Thereaction between lithium and iodobenzene was also carried out inethereal solution, and the sole product formed was diphenyl in smallquantity.The reactions between lithium and bromobenzene and methyliodide only took place when heated in sealed tubes for about sixhours a t 250O.The tubes were then cooled in liquid air andopened, and the gases evolved on warming collected and analysed.The residue was then treated with water, and in the case of methyliodide further quantities of gas were evolved with the evolutionof heat.this was distilled over in steam:In the case of bromobenzene,Reacting substance. Experimental conditions.Iodobenzene . . . . . , . . . . . . . . .Bromobenzene . . , . . . . . . . . .p - Bromo toluene . . . , . . . . .p- Chlorotoluene . . . . . . . . .m- Chloroaniliue . . . . . . . . .p-Chloroaniline . . . . . . . ..p-Bromoacetanilide.. . , . .p - Chlorophenol . . . . . . . . .a-Chloronaphthalene .. .Methyl iodide ... .. . .. . . , ,?t-Propyl iodide . . . , . . . . ,sec. -0ctpl iodide . . . ... . . .Heated 1 hour a t 188"Heated in sealed tubea t 150" for 8% hoursHeated 14 hours a tHeated 49 hours a tHeated + hour a t 230"184"3 50"Heated 1& hours a tHeated 2 hours a t 210"230"Heated Yeveralniinutesat 217"Heated 173 hours a t263"Heated in a sealed tubefor 4& hours a t 200"Heated 1& hours at46'5"Heated 20 hours a t220"benzene was formed, andProducts.70 per cent. benzene & diphenylBenzene and diphenyl24 per cent. toluene7 per cent. toluene ; p-ditolyl80 per cent. aniline; rn-dianiino-diphenpl, traces of carbyl-aniinc68 per cent.aniline, traces ofcarby lam ine40 per cent. aniline, 12 percent, acetanilide14 per cent. phenolNaphthalene ; a-dinaphthyl27 per cent. ethane, 33 per cent.iiiathane mixed with 10 percent. hydrogenn-hesctne ; n-propane9 per cent. octane ; 17 percent. httxadecane, m. p. 20"The calcium used in these experiments was the rasped varietysupplied by Kahlbaum; it was quite bright and metallic-looking inappearance, but occasionally had a slightly bluish tinge, whichmay have been due to a superficial coating of oxide. The reaction8were first tried at the boiling point of the organic substance used,and as in no case did the reaction proceed t o a marked extent, theywere then carried out in sealed tubes a t temperatures varyingfrom 160° to 250O.The substances were mixed in equimolecularquantities. After cooling, the tubes were immersed in liquid airand opened. No gas was evolved on opening, but on warming tUSHER : RADIUM EMANATION. 389the at.mospheric temperature, gas was evolved, which consistedmainly of hydrogen with small quantities of methane, acetylene,and carbon dioxide. This indicates that calcium, like magnesium(Trans., 1908, 93, 1823), has the property of absorbing largequantities of hydrogen a t low temperatures. The solid productswere then cautiously treated with water, and any gas evolved wascollected and analysed. The aqueous mass was then distilled in acurrent of steam, and the products, indicated in the table below,collected. The crystalline product of the reaction between pchloro-phenol was pressed on a porous plate and then washed with smallquantities of absolute ether to remove any unchanged chloro-phenol, dried, and analysed :Found, Ca = 23.1.OH*C,H,*CaCl requires Ca= 23-7 per cent.The lower alkyl halides reacted with calcium when heated at250° in a sealed tube, but the products could not be obtained, owingto the bursting of the tubes.No matter what precautions weretaken, the tubes always burst after they had been heated for aboutone hour, indicating that a violent reaction had suddenly takenplace.The following table gives a brief summary of the reactions carriedout and their products:Reacting substance. Experimental conditions. Products.Iodobenzene .. . . . . . . , . . . , , . Heated in a sealed tubeat 200" for 16 hoursp-Chloroaniline.. . . . , . . , . . , Heated in a sealed tubea t 155" for 14 hoursp-Chlorophenol.. . . . , . , . . . , Heated in a sealed tubea t 160" for 124 hoursp-Bromoacetanilide . . . . . . Heated in a sealed tubeat 200" for 15 hours40 per cent. benzene ; 2 pcrcent. diphenyl31 -5 per cent. aniline36 per cent. phenolSmall quantities of aniline andacetanilide, with a trace ofcarbylamineCHEMICAL LABORATORY,BEDFORD COLLEGE, W