( 328 ) 



1iA(lr(),i;(Mi lliioritlo. Tlio'^e clieiiiisls are oven (»f opinion lliat benzene 

 tlnoi'ide ina\ llms l»e readilv prepared l>v llic kilo. As re^anls tlie 

 conrse ot" llie i'caclion onr experiences are (piilc in liarnionv willi 

 those of Waij,A(I1 and IIkisi.kk, hnl we dilFci- in llic appi'eeialion of 

 lln' eonxenienee of llie nielliod. A|)ai't from llie facl llial in onr 

 nnmerons expei'inieiits we Inue ncxer succeeded in ol)lainin,u llie 

 vlek! of 50"/,, (on an avera.U'e we onlv izol «^0" „ from llie aniline 

 cniplo\ed) w liicli lliev claim lo olMaiii. llie reco\erv of llic pipcridiii(> 

 proved to lie N'crv tedious. Xolw illislandin.ü,' its pi-icc is consideralilv 

 loNvei' lliaii il used to l»c. as il is now prepaied l»v elecirolvlic 

 reduction of p\ ridiiic il is slill sncli llial lliis i-ccoxcrv could nol he 

 a\()i<led. Tlie base must bc auaiii indalcd in a slate of |»erlecl piirit v, 

 because llie \ icld of dia/.opipcrididc bcconio \'crv small il' llie smallest 

 iin|»uril\ should bc piescnl. The niclIiod is also \erv Icdioiis as 

 111)1 more than 10 uranis of dia/.opiperidide al a lime should Ix^ 

 treated willi Indrolliioric acid. otherwise llie reaclion becomiiiLi' too 

 \i()lenl. Afier lia\ inu pi'epare<l aboiil 150 orams of benzene fluoride in 

 this \\a\ wc. iherefore. decided lo abandon this method and lo endea- 

 \()ur lo obtain ben/ene lluoride bv the direcl dia/olalioii of aniline. 



For this |»urpo.-e \ \i,i:ntim:k aiul Scuwakt/ liax'e laken onl a 

 patent (( 'eiitralblall 1<S<I8 I, 1224) consislinu- in healiiiLi- a solulioii of 

 benzenedia/onium chloride with livdroiieii lluoride. We niav sunrise 

 that llie product will be a IxMizene lluoride conlaminaletl willi benzene 

 chloride: (M1 follow inu' their directions this pro\c'<l lo be llie case lo 

 su(di an extent thai aller repealed frjiclionalion of llie product 100 

 Urams of aniline \ ielded onlv Iwo i:rams of fairlv pure benzene 

 llu<»ride. This showed that in the dia/olalioii of aniline, intended for 

 the pre[)aralioii of benzene lluoride hydrochloric acid should be a\ (»ided. 



1 do nol wish lo eiiler inio paiiiciilars as lo the xarioiis ways 

 ill which we liaxc tried lo prep;ii-e benzene lluoride directly 

 from aniline. 1 )i'. Ukkkman has >laled soiiKMliinu- aboiil this in his 

 (lisserlalion. ll will be suflicieiil lo menlion here ihal the yield 

 of the desired product increased with the amouiil of liydrolbioric 

 acid emploxcil. This is ilie niellio<l which wc liiially adopte ' : 113 

 uraiiis of aniline are dissohed in sulphuric acid and diazotaled in 

 the usual niaimei, care bein.u' taken that the xoliime of liipiid does 

 not exceed 1.25 litre. The ice-cold solution is then poured slowly 

 with \iii()rous slirrinu' into a copper \ essel conlaiiiiiiü- 500 cc. of 557„ 

 hydrotluoric acid healeil nearly to llie boilinii' poiiil and kept at that 

 teni[)eratu!-e. The benzene lluoride distills oxer and is condensed in a 

 leaden \\orin-coiidenser surrounded by ice and sail. The distillate 

 consists of a colorless li([uid, which is b'eed fnuii traces of phenol 



