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oily liquid which solidified after some time to a crystalline mass,
and to this new organic base they gave the name toluidine. The
aqueous distillate obtained in the preparation contained some
ammonia and a not inconsiderable amount of base in solution ;
the whole distillate was therefore treated with an excess of
ammonium oxalate, evaporated to dryness on the water-bath
and the residue extracted with boiling absolute alcohol,
ammonium oxalate being in this way left undissolved. On
cooling, toluidine oxalate separated out in white crystals, which
were washed, dissolved in hot water, and decomposed with
concentrated caustic potash solution. The oil which separated
out solidified on cooling to a radiating crystalline mass of
pure toluidine, the properties of which were then accurately-
investigated.

After the discovery of the aniline dyes, aniline and toluidine,
1 Hofmann, Bcr. Deutsch. Chem. Ges. xii. 1371.



TOLUIDINES. 55



or rather a mixture of the two called aniline oil, was manu-
factured on the large scale; and Rosenstiehl found in this
mixture a liquid base, isomeric with the ordinary toluidine, to
which he gave the name of pseudotoluidine. We have already
pointed out that the three nitrotoluenes are formed in varying
quantities by the nitration of toluene. If concentrated acid
be employed without cooling, paranitrotoluene is chiefly formed,
and this yields on reduction the solid paratoluidine obtained by
Hofmann and Muspratt. If, however, a weaker acid be employed,
and the temperature be kept low, more of the ortho-compound is
formed, and it is from this that the pseudotoluidine is derived ;
a small quantity of metanitrotoluene being, however, invariably
produced.

The toluidines are manufactured on a large scale ; the para-
compound is that which is most readily obtained in the
pure state, as the purification of paranitrotoluene offers no
difficulties, whilst it is very difficult, working on the large
scale, to obtain an orthonitrotoluene free from paranitrotoluene,
so that ordinary commercial orthotoluidine always contains some
of the para-compound together with metatoluidine and generally
a little aniline.

The amount of paratoluidine in such a mixture can readily be
determined by means of the different solubilities of the oxalates
in ether; at 15

Acid paratoluidine oxalate requires 6660 parts of ether,
Acid orthotoluidine oxalate 200

for solution. A small quantity, about 0'2 grms., of the mixture
is dissolved in 80 grms. of ether and titrated with a solution of
T062 grms. of oxalic acid in 250 c.c. of ether until no further
precipitate is formed. Each cubic centimetre of the solution
employed corresponds to 0'005 grms. of paratoluidine. 1 The
end of the reaction can easily be recognised by the acid
reaction of the solution towards litmus- paper as soon as the
orthotoluidine oxalate commences to be formed. The deter-
mination is rendered still more accurate by adding an excess of
oxalic acid solution to the solution of the bases, filtering from
the precipitate, evaporating the ether, dissolving the residue in
a little water and determining the excess of oxalic acid by
decinormal caustic soda solution. 2

! ( Rosmstichl, Ann. Chim. Phys. (18/2). xxvi. 2-19.
2 Loronz. ,hi,i. C/ir,n. PJiarm. clxxii. 190.



AROMATIC COMPOUNDS.



In order to separate larger quantities of the base, an amount
of oxalic or sulphuric acid equivalent to the paratoluidine
present is added, and the whole distilled with steam; ortho-
toluidine alone passes over, and the para-compound as the
stronger base remains behind in combination with the acid
(Rosenstiehl).

Ihle dissolves the bases in ether, precipitates with an ethereal
solution of oxalic acid and from time to time treats a small
portion of the solution with acetyl chloride. The product is
re-crystallized from hot water and its melting-point observed.
Since acetparatoluide melts at 145, and acetorthotoluide at
107, the point at which all the paratoluidine is removed can
readily be recognised. 1

Binschedler gives the following process for the treatment of a
mixture of 30 per cent, of paratoluidine and 70 per cent, of ortho-
toluidine which comes into the market under the name of
"aniline lourde spdciale" : 10 kilos, of the mixture of bases are
gradually added to a solution of 2'5 kilos, of oxalic acid in
25 litres of boiling water to which 6 litres of hydrochloric acid
of specific gravity 1'15 have been added, the mixture being
then heated to the boiling point, and constantly stirred until
it has cooled down again to 60. The crystalline precipitate
which consists of pure paratoluidine oxalate, is rapidly filtered
off, pressed, and washed with a little water ; 2 kilos, of oxalic
acid are now added to the filtrate, a mixture of the oxalates
being thus precipitated. When oxalic acid produces no further
precipitate in the mother-liquor, it is distilled with caustic
soda, orthotoluidine being obtained which contains a very small
quantity of paratoluidine and only traces of aniline. 2

Another method of separation, which has been patented by
Leo Levy, depends upon the behaviour of the hydrochlorides of
the bases towards sodium phosphate. Aniline hydrochloride
gives the following reaction :

Na. 2 HP0 4 + 2C 6 H 5 NH 3 C1 = 2NaCl + (C 6 H 5 .NH 3 ) 2 HPO 4 .

Paratoluidine hydrochloride behaves in a similar manner,
while the orthotoluidine salt yields 80 per cent, of the free base
and 20 per cent, of the acid phosphate :

1 ) C 7 H 7 .N H 2 HC1 + Na 2 HP0 4 = C 7 H 7 .NH 2 + NaH 2 PO 4 + NaCl.

2) C 7 H 7 .NH 2 HCl + NaH 2 P0 4 = (C 7 H 7 .NH 3 )H 2 P0 4 +NaCl.

1 Jwrn. Prakt. Chem. [2] xiv. 449. 2 Bffft 2)^^ Chem . Gcs. vi. 448.



ORTHOTOLUIDINE. 57



The mixed hydrochlorides are therefore treated with a
solution of sodium phosphate ; the crystalline mass which is
formed is then dissolved by warming, and the orthotoluidine
removed from the surface. On cooling, the phosphates of aniline
and paratoluidine separate out completely, while the phosphate of
orthotoluidine remains in solution. The sodium phosphate can
be recovered after separation of the bases ; sodium arsenate may
also be employed. 1

Another process for the separation of orthotoluidine from
aniline oil by means of the nitrate has been described by
L. Schad.2

2047 Orthotoluidine, discovered by Rosenstiehl, 3 is formed by
the reduction of orthonitrotoluene and by the distillation of
paramidotoluic acid with lime. 4 It is a colourless liquid re-
sembling aniline very closely ; it soon becomes brown in the air
or on exposure to light, boils at 198'5, has a specific gravity of
1'003 at 20'2, and does not solidify at - 20. A solution of this
base in monohydrated sulphuric acid gives a blue colouration with
a solution of chromium trioxide in sulphuric acid of the same
strength ; the colour changes to a stable reddish violet on
dilution. Nitric acid added to the sulphuric acid solution gives
an orange to brown colouration, passing into yellow on the addi-
tion of water. If the base be dissolved in ether and an equal
volume of water added, the lower layer of the solution gives
a yellow to brown colouration with dilute sulphuric acid. If the
ethereal layer be now removed and shaken with dilute sulphuric
acid, it becomes coloured a stable reddish violet (Lorenz).

Orthotoluidine further differs from its isomerides in giving a
green colouration with ferric chloride and a little paradiamido-
benzene. This reaction is so delicate that a solution containing
1 in 10,000 gives a tolerably deep colouration, and a solution only
one-tenth as strong as this assumes a distinct shade of green. 5 All
commercial aniline gives this reaction, as also does that obtained
by the distillation of indigo with caustic potash, which was con-
sidered to be chemically pure until Bosenstiehl proved that it
contained orthotoluidine.

The salts of orthotoluidine have been investigated by Beilstein
and Kuhlberg.

1 Ber. Deutsch. Chem. Ge*. xvi. 980. 2 Hid. vi. 1361.



3 Zcitschr. Chem. [2] iv. 557.

4 Beilstein and Kuhlberg, Ann. Chem. Pharm. clvi. 75.

5 Monnet, Reverdin and Nolting, Ber. Deutsch. Chem.



olting, Ber. Deutsch. Chem. Ges. xi. 2278. See
also Reinhardt and Stadel, ibid. xv. 29.



58 AROMATIC COMPOUNDS.

Orthotoluidine hydrochloride, C 7 H 9 NC1H + H 2 O, forms white
crystalline crusts, 37'4 parts of which dissolve in 100 parts of
water at lo'o ; it is still more readily soluble in alcohol.

OrtJwtoluidine hydrobromide, C 7 H 9 N.BrH, crystallizes very
easily in large rhombic prisms ; the hydriodide resembles it, but
is partially decomposed by water. 1

Orthotoluidine sulphate, (C 7 H 9 N) 2 H 2 SO 4 , forms small crystals
which become coloured violet to green in the air; 100 parts of
water at 22 dissolve 7'5 parts. It is only slightly soluble in
alcohol.

Orthotoluidine nitrate, C 7 H 9 N.HNO 3 , crystallizes in small
plates ; 100 parts of water at 19'2 dissolve lO'Ol parts.

Orthotoluidine oxalate crystallizes in small colourless plates ;
100 parts of water at 21 dissolve 2'38 parts.

Methylorihotoluidine, C 6 H 4 (CH 3 )N(CH 3 )H, is formed when
750 grms. of Orthotoluidine are heated for a day to 200 220
with 400 grms. of methyl alcohol and 700 grms. of hydrochloric
acid. The product is distilled in steam, and every 100 grms. of
distillate dissolved in 120 grms. of hydrochloric acid and 300
grms. of water, the solution being then treated with a con-
centrated solution of 40 grms. of sodium nitrite, the mixture
being cooled and well agitated. The methylorthotolylnitros-
amine, C 6 H 4 (CH 3 )N(CH 3 )NO, formed, which is very similar to
methymitroso-aniline, is extracted with ether, reduced with tin
and hydrochloric acid, decomposed with caustic soda, and distilled
with steam.

Methylorthotoluidine is a colourless liquid which rapidly
becomes coloured violet-brown in the air, and boils at
207 208 . 2

Dimdhylorthotoluidine, C 6 H 4 (CH 3 )N(CH 3 ) 2 . Thomsen ob-
tained this compound by the distillation of trimethyltolyl-
ammonium hydroxide; it is also formed, together with other
products, when trimethylphenylammonium iodide is heated to
220 230 . 3 It can readily be prepared pure by heating 750
grms. of Orthotoluidine for two days with 670 grms. of methyl
alcohol and 700 grms. of hydrochloric acid, the product being
repeatedly rectified (Monnet, Reverdin and Nolting). It is a
colourless liquid which has a characteristic aromatic odour and
boils at 183.

; ? T tftiiei v B t - Deutsch - ch * m - Gcs - xvi - 2s -

net, Keverdin and Nolting, Ber. Dcutsch. Chem. Ges. xi. 2278. See also
t and Stadel, ibid. xv. 29. > Hofmann, ibid. x. 1585.



DERIVATIVES OF ORTHOTOLUIDINE. 59

Trimethylorthotolylammonium iodide, C 6 H 4 (CH 3 )N(CH 3 ) 3 I, is
formed by the continued action of methyl iodide on ortho-
toluidine, 1 and crystallizes in large needles which assume a faint
purple tint in the air.

Boiling-point.

Ethylorthotoluidine, C 7 H 9 N(C 2 H 5 )H, liquid 213 214
Diethylorthotoluidine, 2 C 7 H 9 N(C 2 H 5 ) 2 208 209.

Phcnylorthotolylamine, C 6 H 5 .NH(C 7 H 7 ), is formed, together
with diphenylamine and di-orthotolylamine, when orthotoluidine
is heated with aniline hydrochloride to 280. 3 It is a crystalline
substance which melts at 41, boils at 297 299, and gives a
violet-blue colouration with nitric acid.

Di-orthotolylamine, (C 7 H 7 ) 2 NH, is a liquid boiling at 304
308.

Acctorthotoluide, C 7 H 7 .N(C 2 H 3 O)H, forms long needles, melts
at 107 and boils at 296; 100 parts of water at 19 dissolve
0-86 parts (Beilstein and Kuhlberg).

Orthotolyl carbamide, (C 7 H 7 )NH.CO.NH 2 , is formed by the
action of potassium cyanate on orthotoluidine hydrochloride ; it is
insoluble in cold water, moderately soluble in hot water, and
readily in alcohol, crystallizing in tablets which melt at 185 . 4

Di-orthotolyl carbamide, (C 7 H 7 ) 2 NCO.NH 2 , is formed by the
action of carbonyl chloride on orthotoluidine, by heating the
latter with urea, 5 or by heating its hydrochloride with cyanamide
to 100. It is insoluble in water, but slightly soluble in alcohol,
crystallizing in fine needles which melt at 243.

Orthotolyl carbamide, or Orthotolyl isocyanate, CON.C 6 H 4 .CH 3 .
When orthotoluidine is acted upon by chlorocarbonic ether,
orthotolyl urethane, NH(C 7 H 7 )CO.OC 2 H 5 , is formed in crystals
melting at 46, 7 and on heating with phosphorus pentoxide is
converted into the isocyanate, which is a liquid boiling at 186
and possessing a penetrating odour (Girard). Water decom-
poses it with formation of ditolyl carbamide.

Orthotolyl thiocarbamide, (C 7 H 7 )HN(CS)NH 2 , is obtained by
the action of ammonia on orthotolyl mustard oil ; it melts at
155 and is readily soluble in boiling water. 8

Thomsen, Bcr. Dcutsch. Chem. Gen. x. 1586.

Stadel and Reinhardt, loc. cit. ; Norton, Am Chcm. Journ. vii. 118.

Oirard and Willm, Bull. Soc. Chim. xxv. 248.

Cosack, Ber. Deutsch. Chcm. Ges. xiii. 1089.

Girard, ibid. vi. 444. Berger, ibid. xii. 1859.

Lachmann, ibid. xii. 1349 ; Neville and Winther, ibid. xii. 2324.

Staats, ibid. xiii. 135.






G0 AROMATIC COMPOUNDS.

Di-orthotolyl thiocarbamide, (C 7 H 7 .NH) ;2 CS, is obtained by the
action of carbon disiilphide on an alcoholic solution of orthotolu-
idine. 1 It crystallizes from hot alcohol in needles melting at 158.

Orthotolyl thiocarbamide, or Orthotolyl mustard oil, CSN.C 6 H 4 .
CH 3 , is formed when the compound just described is boiled
with' fuming hydrochloric acid. It is a strongly refractive liquid,
boiling at 239 and possessing a pungent odour (Girard).

It combines with aniline forming pTienylorthotolyl thiocarbamide,
(C 6 H 5 )NH(CS)NH(C 7 H r ), which has also been prepared from
orthotoluidine and phenyl mustard oil (Staats) ; it forms long
needles melting at 139, and is decomposed by hydrochloric
aoid into aniline and tolyl mustard oil.

2048 Metatoluidine was obtained by Beilstein and Kuhlberg
by the reduction of metanitrotoluene, 2 which is best effected by
means of stannous chloride and hydrochloric acid (Cosack).
According to Widman, it is also formed when metanitrobenzyl-
ene chloride, C 6 H 4 (NO 2 )CHC1 2 , obtained by the action of phos-
phorus chloride on metanitrobenzaldehyde, is reduced with zinc
dust and hydrochloric acid. 3

It is a colourless oily liquid which has a specific gravity of 0'998
at 25, and becomes converted into a brown resinous mass when
exposed to the air (Lorenz) ; it boils at 197 and does not solidify
even at 13. If it be dissolved in monohydrated sulphuric
acid and treated with a sulphuric acid solution of chromium
trioxide, a yellowish brown liquid is obtained which becomes
brown on gentle heating, and is coloured greenish yellow by the ;
addition of a little water, a larger quantity rendering it colour-
less. Nitric acid added to the original solution produces a
reddish colouration which rapidly becomes a deep blood-red, and
then a dark dirty-red, and is converted into orange by the
addition of water. When a solution of the base in equal
volumes of ether and water is treated with bleaching powder j
solution, the aqueous layer is coloured brownish yellow and .
becomes turbid, while the ether exhibits a reddish fluorescence ;
if the ether be poured off and shaken up with water and a
drop of dilute sulphuric acid, the water becomes coloured a
faint violet.

The salts of metatoluidine have been investigated by Lorenz. 4

\ G } T&Td ' Ber - Deutsch. Chem. Ges. iv. 985 ; Berger, ibid. xii. 1854.
2 .47171. Chem. Pharm. clvi. 83.

Ber. Dcutsch. Chem. Gcs. xiii. 676 ; xiv. 2583. See also ibid. xiv. 1403.
4 Ann. Cfiem. Pharm. clxxii. 177.



METATOLUIDINE. 61



Metatolilidine hydrochloride, C 7 H 9 N.C1H, crystallizes from a
very concentrated aqueous solution in thin tablets, and from
alcohol in thin, pale red crusts.

Metatoluidine sulphate, (C 7 H 9 N) 2 S0 4 H 2 , crystallizes in long,
transparent, light red, radiating needles, which are insoluble in
ether, slightly soluble in alcohol, and more readily in water, 100
parts of which at 14 dissolve 6'25 parts.

^[ctatoluidine nitrate, C 7 H 9 N.NO 3 H, crystallizes in large, pale
red, rhombic plates, 16 '42 parts of whfch dissolve in 100 parts of
water at 155; it is still more soluble in alcohol, but only
slightly soluble in ether.

Acid mctatoluidine oxalate, C 7 H 9 N.C 2 O 4 H 2 , forms warty masses
consisting of fine silky needles, which are only slightly soluble
in ether, alcohol and water; 100 parts of the latter at 13
dissolve 2'65 parts. When its solution is warmed with meta-
toluidine, the salt, (C 7 H 9 N) 3 (C 2 4 H 2 ) 2 , separates out in a mass
of rhombic plates which are still less soluble than the mono-
acid salt. If an excess of metatoluidine be added in warm
alcoholic solution to oxalic acid, small rhombic plates separate
out on cooling in such quantity that the liquid solidifies to a
jelly. These crystals appear to be the hydrated normal salt;
after washing with alcohol and drying, they possess the appear-
ance of cholesterin; they are scarcely wetted by water and
when heated with it for a long time decompose into the acid
salt and the free base.

Methylmetatoluidinc, C 6 H 4 (CH 3 )N(CH 3 )H, is formed, together
with dimethylmetatoluidine, by the action of methyl iodide on
the primary base. The product is extracted with ether and
freed from unattacked metatoluidine by the addition of sulphuric
acid, an alkali is then added, the ether distilled off and the residual
oil dried and heated with acetic anhydride. On distillation,
acetic acid and acetic anhydride first come over, followed by
dimethyltoluidirie and finally by methylacetoluide, boiling above
250. This is purified by repeated distillation and decomposed
by heating with dilute sulphuric acid, pure methylmetatoluidine
being thus obtained ; it is a colourless liquid which boils at
206 207, and possesses a characteristic aromatic odour.

Dimethylmetatoluidine, C 6 H 4 (CH 3 )N(CH 3 ) 2 , boils at 215
(Wurster and Riedel), and has a characteristic odour differing
from that of its isomerides, but resembling that of dimethyl-
aniline. 1

1 Nolting, Ber. Dcutsch. Chcm. Gcs. xi. 2278.



AROMATIC COMPOUNDS.



Nitrosodimethylmctatoluidine, C C H 3 NO(CH 3 )N(CH 3 ) 2 , is formed
on the addition of sodium nitrite to a cooled solution of di-
methylmetatoluidine in hydrochloric acid. The hydrochloride
thus prepared crystallizes from a hot, acidified solution in light
yellow to greenish yellow needles which are only slightly soluble
in cold water. Sodium carbonate liberates the free base, which
crystallizes from ether in small, green plates or long needles,
melting at 92. It is precipitated by petroleum ether from a
solution in chloroform in moss-green needles, and separates from
benzene in large, dark green crystals containing benzene of
crystallization, which they lose in the air together with their
colour and lustre. All its solutions are coloured deep green. It
crystallizes from water in small, lustrous green plates.

Like nitrosodimethylaniline, it forms deep steel-blue coloured
compounds with aniline, orthotoluidine, &c., and does not give
Liebermann's reaction in the cold. Boiling dilute caustic soda
converts it into nitrosocresol ; potassium permanganate oxidizes
it to ntirodimettylmetatoluidine, C 6 H 3 NO 2 (CH 3 )N(CH 3 ) 2 , which
crystallizes in long yellow needles, melting at 84. It is re-
duced by tin and hydrochloric acid to dimethyldiamidotoluene
C 6 H 3 (CH 3 )(NH 2 )N(CH 3 ) 2 .

Since the two isomerides of dimethyltoluidine give no
nitroso-compounds, the presence of metatoluidine can readily
be detected in orthotoluidine, and its amount approximately
determined ; to effect this the hydrochlorides are prepared, the
greater part of the orthotoluidine salt removed by crystallization,
the mother-liquor evaporated to dryness, and the residue heated
with methyl alcohol ; the almost insoluble nitrosodimethylmeta-
toluidine is then prepared directly from the mixture of dimethyl-
toluidines thus obtained. The two bases can also be separated
by fractional distillation, since the ortho-compound boils at 183
and the meta-compound at 21 5 . 1

Metaditolylaminc, (C 6 H 4 .CH 3 ) 2 NH, is formed when meta-
toluidine is heated with its hydrochloride. It is a thick, oily,
light yellow liquid which becomes coloured brown in the air and
boils at 319 320. 2

Acetmetaioluide, C 6 H 4 (CH 3 )N(C 2 H 3 O)H, crystallizes on the
gradual evaporation of its aqueous solution in long needles
united to form bushy aggregates ; it melts at 65'5, and boils at

1 Wurster and Ri.-del, Ber. Deutsch. Chcm. Ges. xii. 1796.
'- Cosaek, ibid. xiii. 1083.



PARATOLUIDINE. 63



303. 100 parts of water at 13 dissolve 0'44 parts (Beilstein
and Kuhlberg).

Metatolyl carbamide, (C 6 H 4 .CH 3 )HN.CO.NH 2 , lias been pre-
pared from metatoluidine and potassium cyanate ; it crystallizes
from water in small plates, and from alcohol in tablets or
needles, melting at 142.

Dimetatolyl carbamide, CO(NH.C 7 H 7 ) 2 . When metatoluidine
is acted upon by chlorocarbonic ether, metatolyl urethane,
(C 7 H 7 )HKCO.OC 2 H 5 , is formed; this is a liquid which on
distillation in the moist state yields alcohol, carbon dioxide, and
dimetatolyl carbamide. The latter crystallizes from hot alcohol
in long needles melting at 217 (Cosack). 1

Metatolyl thiocarbamide, (C 7 H 7 )HN.CS.NH 2 , is obtained by
the action of ammonia on metatolyl thiocarbimide. It is readily
soluble in alcohol, slightly in cold, and more freely in hot water,
and crystallizes in prisms which form star-shaped aggregates,
and melt at 103 . 2

Dimetatohjl thiocarbamide, CS(NH.C 7 H 7 ) 2 , is formed when an
alcoholic solution of metatoluidine is heated for a long time with
carbon disulphide. It crystallizes in concentrically arranged
needles, melting at 122, which are scarcely soluble in boiling
water but dissolve readily in alcohol.



is formed when the compound just described is heated with
concentrated hydrochloric acid. It is a colourless liquid which
boils at 244 and possesses the characteristic smell of the mustard
oils in the highest degree ( Weith and Landolt.)

2049 Paratoluidine is formed by the reduction of parauitro-
toluene and by heating methylaniline hydrochloride for a day to
350 ; methylaniline hydriodide, on the other hand, gives a liquid
toluidine, 3 which is probably the ortho-compound. It may also
be obtained by heating paracresol with the compound of zinc
chloride and ammonia to 300 . 4 It is slightly soluble in
water, readily in alcohol and ether, and crystallizes from
hot, dilute alcohol in large, colourless plates which melt
at 45 and have a peculiar aromatic odour resembling that of
aniline. According to Hofmann and Muspratt it boils at
1 98, while Stadeler found its boiling-point to be 204 206 . 5
When it is dissolved in monohydrated sulphuric acid and treated

1 Ber. Tteutsch. Ckem. Ges. ; see also xii. 1450.

" "VVeith and Landolt, ibid. viii. 713. 3 Hofmann, ibid. v. 720.

4 Buch, ibid. xiv. 2345 ; xvii. 2637. 5 Jahrcsber. 1865, 409.



64 AROMATIC COMPOUNDS.

with a solution of chromium trioxide in acid of the same strength,
it is only coloured yellow. A drop of nitric acid added to the
original solution produces a blue colouration, which soon passes
through violet and red to brown (Lorenz) ; in presence of aniline
or orthotoluidine no blue colouration is produced, but the liquid
becomes coloured blood-red. Bleaching powder solution gives
no colouration with solutions of pure paratoluidine ; in order
therefore to detect the presence of aniline in paratoluidine, the
mixture is dissolved in ether, and shaken up with an equal
volume of water, a solution of bleaching powder then being added
drop by drop. If aniline be present, the ether assumes a blue
colour when the solution is agitated (Rosenstiehl).

The salts of paratoluidine have been investigated by Hofmann
and Muspratt and by Beilstein and Kuhlberg. 1

Paratoluidine Jiydrochlorid.c, C 7 H 9 N,HC1, crystallizes in white
crusts, which become coloured in the air. 100 parts of water at
11 dissolve 22'9 parts, while 100 parts of 89 per cent, alcohol
dissolve 25 parts at 17.

Paratoluidine liydrobromide, C 7 H 9 N, HBr, crystallizes in white
plates ; the hydriodide is very similar (Reinhardt and Stadel).

Paratoluidine sulphate, (C 7 H 9 N) 2 H 2 SO 4 , forms lustrous, scaly
crystals, 5'06 parts of which dissolve in 1 00 parts of water at
22 ; they are stilt less soluble in alcohol.

Paratoluidine nitrate, C 7 H 9 N, HNO 3 , crystallizes, when its solu-
tion is rapidly cooled, in large rhombic tablets ; when allowed to



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