II.-On the Synthesis of Butydene. By ERNEST CHAPMAN. THEOPHRON IT is now some time since Kurtz succeeded iu synthetically forming amylene by the action of zinc-ethyl upon iodide of allyi. It is obvious that iodide of allyl C,H,I would be isomeric with mono-iodpropylene and this latter compound is homologous with monobromethylene. I therefore thought it worth while to treat this latter substance with zinc-ethyl with the idea of forming butylene. The ziuc-ethyl was contained in a tubulated retort surrounded by ice and salt. Monobromethylene was introduced into the CHAPMAN ON THE SYNTHESIS OF BUTYLESE. retort in the state of vapour. It was at once condensed. Care was taken not to add excess of it. The retort was then removed from the freezing mixture and gently warmed.The liberated vapours were conducted through a U-tube surrounded by ice and salt. In this manner about three c. c. of a colourless liquid were obtained. It mas introduced into a small distilling apparatus and the boiling point carefully taken. It was found to lie between 12 and 14'. The sp. gr. of the liquid was -739 at 0"C. A small portion of it was carefully tested for bromine by passing it over red-hot caustic lime. No bromine was detected. The remainder of the liquid was treated with bromine. The two bodies combined with con- siderable evolution of heat. The operation was conducted in a long test-tube immersed in ice-cold water. The resulting product was dried and distilled. It was found to boil between 158' and 160°C.thoilgh a small portion of it had a higher boiling point. It was distilled three times to remove this trace of liquid of higher boiling point By this time the total amount of liquid had been reduced to little more than 1c.c. It weighed 1.526 grammes. It mas then digested with solution of canstic potash in alcohol free from chlorine. TIie amount of bromine which it yielded to this agent corresponded with the amount required on the assumption that we were dealing with bibromide of butylene. This substance would of course give only up one equivalent cf bromine. There-fore on distilling off tlie alcohol and gently igniting the residue we should obtain a mixture of bromide of potassium and caustic potash. It was in this mixture that the bromine was determined as bromide of silver.1.526 of substance yielded 1.326 AgBr therefore 36-97 per cent. Br. Theoretical per centage 37.037. The alcohol distilled cjff was diluted with ice-cold water a few drops of an oily liquid rose to the surface. This liquid on treat- ment with bi-chromate of potash and concentrated sulphuric acid yielded bromine. The reaction to which the butylene owes its existence is as follows :-Zn(C,H,) + 2C,H,Br = ZnBr + 2C,H,. It appears to me that this reaction will enahle us to obtain the whole of the olefines normal as well as abnormal for it is almost certain that dibromethylene would act upon two equivalents of CHAPAMAX AND THOIZI’ ON THE RELATION zinc-ethyl prodnciug hesylene-a secondary hexylene no doubt ; aid iri a similar nianner any other required olefine could be obtaiued.