33 ON NORMAL AND ISO-PROPYLPARATOLUIDINE. 111.-Note on Nornznl arid Iso-23l"opyl~aTatoluidine. By E. HORI and H. F. MOIZLEY. IK connection with an investigation which we undertook three o r four years ago, we thought it desirable to be able t o distinguish with certainty between normal and iso-propylparatoluidine. We had completed the examination of this point when the .investigation of which this was to form a part was brought to an abrupt termination by the departure of one of us from England. Nevertheless, we think that. t'he following observations, made in 1887, ought, perhaps, to be recorded. FOL. LIX. D33 HORI AND MORLEY ON NORNAL Isoprop ylparatoluidine. An almost theoretical yield of isopropyltoluidine may be obtained by heating isopropyl iodide with paratoluidine in equimolecular proportions f o r two days in sealed tubes at 130". The isopropyl iodide employed was obtained i n the usual way from glycerol, iodine, and amorphous phosphorus, and boiled at 89-91", The crude iso- propylparatoluidine was purified by conversion into its nitrosamine, the nitrosamine being then reconverted into the base by treatment with tin and hydrogen chloride. Iso~ropy123aratoZyZnitrosanzine, (CH,),CH*N(NO)*C,H4-CH3, sepa- rates frum alcohol in beautiful, slightly yellowish crystals, melting at 58-59' (uncorr.). It is easily soluble in ether, benzene, alcohol, and glacial acetic acid, but insoluble in water.It cannot be distilled with steam. 100 grams of alcohol (984 per cent.) dissolve 65 grams of the iiitrosamine at 22". On combustion, 0.2598 gram of the substance gave 35 C.C.of nitrogen at 18" C. and 754 mm. bar. pressure corre- sponding to 15.89 per cent. nitrogen, the calculated percentage being 15-73. I n the conversion of the nitrosiLmine into isopropylparatoluidine by warming with tin and hydrogen chloride solution, a yield of only 60 per cent. of the theoretical amount was obtained, but we failed to improve this yield by other methods of effecting the conversion. Isopropylparatoluidine may also be pile pared from diazotoluene- toluide, C7H7*N3,*NHG7H7, an alcoholic Rolution of sodium ethylate, and isopropyl iodide by heating the mixture for five hours on the water-bath, distilling off the alcohol, pouring the solution into cold water, and decomposing the precipitate with hydrogen chloride ; but the yield in this case is not very good.Iso~rop1JZparatoZz~idine is a colourless oil, which slowly becomcs coloured. Its deizsity is 0.9226 gram per C.C. a t 20", 0.9209 a t 23", 0.9129 at 35", 0.8988 at 51", and 0.8937 at 56". The density at its boiling point, determined by Ramsay's method, was found in three experiments to be 0.7469, 0.7452, and 0.7477, the mean being 0,7466. This gives a moleculay specific volume of 199.57, whilst Bruhl's formula for specific volumes would give 199.50 as the calculated number. The index of refraction was kindly determined by Dr. A. H. Pison, of University College, to be as follows :- It boils a t 219" to 221" (nncorr.). Line. Wave-length. Index of refraction. Ha.. .............. 6562 1.5277 D ................ 5892 1.5322 Hp................ 4861 1.5473AND ISO-PROPLYPARATOLUIDIXE. 35 Calculating the molecular refractive energy from the values for the lines Ha and Ha, we obkain 81.4 instead of the theoretical number 79.3. fVorma1 ~so~ropyl23arntoZ~~id~~ae Oxalnte, (CloH,jN)2,H,C,04.-The base forms both a normal and an acid oxalate, but the latter being exceedingly soluble both in water and alcohol is not easily crystal- lised, whilst the former is 0nl-j- slightly soluble in cold water, and can be easily crystallised from dcohol. The normal oxalate crystallises from h o t absolute alcohol in colourless crystals melting at 129-130" (u2corr.). Three deter- minations of oxalic acid gave 23.02, 23.26, and 23.18 per cent. respectively (calculated 23-19>. The Salk is almost insoluble in cold water, but on warming it dissolves with partial separation of the base.100 grams of alcohol (9Sa per cent.) dissolve 4.76 grams at 17" and 5.76 grams at 22". Isopropylpas.atoli~idine Hydrochloride, C1,Hl5N,HCl.-This salt, which separates as colourless crystals, on passing hydrogen chloride into a, solution of the base in ether, crystallises from alcohol in large crystals of wax-like colour melting at 170-171". It is very easily soluble both in water and alcohol, slightly in cold benzene, and easily in boiling benzene, from which it separates in needles [Cl = lS.69 and 18.63 ; calc. 19-13]. The ferroc yanide, (C,, H15N)2,H4-E'eCyS, obtained by precipitation, is a white powder [Fe = 11.55 and 11.12; calc. 10.891. Xomzai P~o~~~aal.atolzt.idine.Normal propylparatoluidine was prepared by heating equimolecular weights of normal propyl iodide and paratohidine for two days in sealed tubes at 160"; the yield being 90 per cent. of the theoretical. The normal propyl iodide used was prepared fieom propyl alcohol, amorphous phosphorus, and iodine, and boiled at 101-103" (uncorr.). The normal propylparatolnidine was purified, like its isorneride, by conversion into its nitrosamine. NornzaZ Pro~yZpal.afolyZnits.osa?ni~c, CH,-CH,-CH,*N(NO)*C,H,*CH,, is an oil, not solidifying at -20'. On heating, it begins to decom- pose below 10CIc, giving off nitrous fumes. In converting it into normal propylparatoluidine, the yield is only 50 per cent., and the boiling point of the resulting base is not so sharp as that of its isomeride, so that some fractional distillation is necessary.Normal Propylparatolicidine is a colourless oil, boiling at 230-233", and does not become much coloured even on standing for a long time. Its solubility is 0.9243 gram per C.C. at 20", 0.9296 a t 23", 0.9172 at 35") and 0.9053 at 51". The density at the boiling point D 23 6 ON NORNAL AND ISO-PROPTLPARATOLUIDINE. was found in four determinations to be 0.7554, 0.7546, 0.7533, and 0.7539, the mean being 0.7543. This gives a molecular specific volume 197.53 (theory 199.50). The index of refraction was kindly determined by Dr. Fison to be as follows :- Ha.. ................ 1.5306 D ................... 1-5367 H g .................. 1.5495 The molecular refractive energy ( 'L- ')A$ calculated from the values for Ha and H p is 82.5.Oxnlates qf Normal P~o~y7pa~atoZzcidine.-Normal propylparatolui- dine forms both normal and acid oxalates ; but the normal oxalate, when in solution, easily decomposes into the acid oxalate and the base, and it is, therefore, difficult to obtain i t in a, crystalline state. The acid oxalate, ( C,oH,,N),C2H,0i, crystallises from alcohol, and melts at 172-173" with decomposition. The percentage of oxalic acid was found t o be 37.86 and 37.644 (calculated 37.65). The acid oxalate is only slightly solu'ule in cold water and alcohol, but easily dissolves on warming. 100 grams of alcohol (98$ per cent.) dissolve 1.4 grams at 21'. On mixing equimolecular proportions of the base and oxalic acid, both in alcoholic solution, a precipitate of the acid oxalate is obtained, but the filtrate, when left to evaporate spontaneously, deposits white powdery crystals of the normal salt (C~oH~~N)2,C,H204 [Percentage of oxalic acid found: 23.25 and 23.08; calc. 23.191.The normal oxalat'e can also be obtained by adding a large excess of the base to a cold alcoholic solution of the acid oxalate, when crystals of the normal salt often separate a t once, and further quantities may be obtained by spontaneous evaporation. The normal oxalate of normal propylparatoluidine melts at 116-117", and is more soluble both in water and in alcohol than the acid salt. Its aqueous solution when warmed becomes milky, from separation of the base, but becomes clear again on cooling. If the solution is heated to boiling, i t deposits, on cooling, the acid oxalate only.Normal and iso-propylparatoluidines may be separated through the difference in the solubility and stability of their oxalates. If a mixture of the two bases be gradually added to an aqueous solution of oxalic acid, sufficient t o form acid oxalates, a crystalline precipitate of the acid oxalate of normal propylparatoluidine is formed. On evapo- rating the filtrate, and allowing it to cool, more of this salt separates, but after repeating this process several times distinct crystals of t h eYOUNG : THE SPECIFIC VOLUMES OF LIQUIDS, ETC. 37 osalate of ieopropylparatoluidine begin t,o appear. On adding potash t o the mother liquor at this point, almost pure isopropylparatoluidine is liberated. The hydrochlovide of normal propylparatoluidine, CIoHl5N,HC1, crptallises from boiling benzene in needles melting at 150-151" [Cl = 18.95 per cent. ; calc. 19.13 pcr sent.]. It is very soluble in -\?;nter and alcohol, slightly soluble in cold benzene, easily soluble in boiling benzene. The f ewocyanide of normal propylparatoluidine, ( CIOH,,N),,H6FeCy6, is a white solid, turning blue on exposwe to light [Fe = 11.09 per cent. ; calc. 10.891.