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In each case the whole of the sulphur is precipitated, whilst 2
equivalents of hydrogen enter into the combination instead of the 4
equivalents of oxygen which are removed. The object of adding
ammonia in the first instance is merely to retain the sulphuretted
hydrogen in solution, so that the reaction may have time to take
place. A large number of new bases have already been formed
by this process, and numerous others will, no doubt, shortly be
discovered. Bechamp has shown that by treating nitrobenzole,
and other nitrous derivatives of the hydrocarbons, with protacetate
of iron, they are reduced ; the protoxide of iron becomes converted
into sesquioxide, and is most of it precipitated in the form of a
basic sesquiacetate of iron, whilst an organic base is formed ; and
this method is even preferable to Zinin's :

Nitrobenzole. Protacet. of Iron. Aniline. Basic Peracet. of Iron.

C 12 H 5 NO 4 + 12 (FeO, Ac) + 2 HO = C 12 H 7 N + 6 Fe 2 O 3 , 12 Ac.

All the bases thus procured are destitute of oxygen : they
resemble ammonia in their mode of combination with oxyacids, an
equivalent of water being essential to the formation of these salts ;
sulphate of toluidine, for example, consists of HO, C 14 H 9 N, SO 3 .

Liebig and Wohler have also formed two bases, termed thialdine
(C 12 H 13 NS 4 ), and selenaldine (C 12 H 13 NSe 4 ), in which sulphur and
selenium are constituent elements. They are procured by the
reducing agency of sulphuretted hydrogen and seleniuretted hydro-
gen respectively, upon an aqueous solution of 3 equivalents of
aldehyd-ammonia : thus in the case of thialdine :

Aldehyd Ammonia. Thialdine.

3(5,11,02, H 3 N) + 6HS = (5^H 13 NS 4 + 2 (H 4 NS) + 6 HO.

(1063) The following order will be observed in the description
of such of the organic bases as, from their important applications,
their bearing upon other groups, or from the mode of their forma-
tion, seem most worthy of notice :


A. Artificial Bases.

1 . Bases which do not contain oxygen ;

a. Aniline series (C B H n-7 )H 2 N ;

b. Pyridine series (C M H re _ 5 )'"N;

c. Quinoline series (C w H w _ n )'"N.

2. Bases obtained by the action of ammonia upon certain
essential oils.

3. Bases obtained by the substitution of electro-negative radicles
for hydrogen in ammonia.

B. Natural Bases.

1 . Volatile oily bases destitute of oxygen :

Conia ; Nicotia ; Sparteia ;

2. Oxidized bases ;

a. Bases of the cinchonas ;

b. Opium bases;

c. Alkalies from pepper;

d. Alkaloids from the strychnos tribe ;

e. Other less known bases ;
/. Caffeine and Theobromine.


i. Volatile bases which do not contain oxygen.
. Aniline series (C^H^^B^N.

(1064) ANILINE, Kyanol, Phenylamide, Phenylia, Crystalline ,
or Benzidam (C 12 H 7 N = C 12 H 5 , H 2 , N). Sp. gr. of liquid 1*020,
of vapour y 210. This remarkable base may be prepared from,
several sources, and by a variety of reactions.

1 . It is contained in small quantity among the products of the
destructive distillation of coal in the process of gas-making.

2. Nitrobenzole is converted by hydrosulphate of ammonia
into aniline and water, whilst sulphur is deposited,

C 12 H 5 N0 4 + 6 HS = C 12 H 5 , H 2 N + 4 HO + 6 S.

A similar reduction takes place under the influence of protacetate
of iron, or of a mixture of zinc and hydrochloric acid.

3. It is also furnished by the distillation, with lime, of nitro-
toluole, or of its metamerides, salicylamide and anthranilic acid,
all of which substances furnish aniline and carbonic acid ; thus :

Nitrotoluole. Aniline.


The product from salicylamide is always accompanied by carbolic
acid (HO, C 12 H 5 O).

4. One of the methods by which aniline is most abundantly
and easily procured consists in mixing finely-powdered indigo with
a concentrated solution of hydrate of potash, and submitting it to
distillation : the mass swells up greatly, and water, holding
ammonia in solution, passes over, accompanied by aniline in the
form of a brownish oil. This oil, when re-distilled, furnishes
pure aniline, amounting to nearly one-fifth of the weight of the

This base is a colourless, limpid liquid, of an agreeable
vinous odour and burning taste. It is very acrid and poisonous.
Aniline remains fluid at 4 F. When dropped upon paper it pro-
duces a greasy stain, which, owing to the volatility of the base,
speedily disappears ; it boils at 360 F. Aniline is a non-con-
ductor of electricity ; it refracts light powerfully. When exposed
to the air it rapidly absorbs oxygen, and becomes converted into
a brown, resinous mass ; it is, therefore, necessary to distil it in a
current of hydrogen, or of carbonic acid. It is heavier than
water, in which it is soluble to a considerable extent ; but on satu-
rating the liquid with sulphate of magnesia, the aniline is sepa-
rated. Aniline has little or no action on test papers ; it dissolves
in unlimited quantity in alcohol, ether, and wood spirit.

Most of the salts of aniline crystallize readily. They are
colourless, but if exposed to the air while moist, they become rose-
coloured. If a slip of deal be plunged into a solution of any of
these salts, it gradually acquires an intense yellow colour. If an
aqueous solution of a salt of aniline be mixed with a solution of
chloride of lime, a deep blue colour is produced, which gradually
passes into a dirty red. With chromic acid these salts strike a
green, a blue, or a black colour, according to the degree of con-
centration of the solutions. Aniline produces a white precipitate
in a solution of corrosive sublimate, and a green crystalline pre-
cipitate in one of chloride of copper. Both precipitates contain
aniline in combination with the metallic chlorides.

When a solution of hydrochlorate of aniline is mixed with
one of nitrite of silver, nitrogen escapes in abundance, whilst car-
bolic acid is separated in oily drops; owing to the reaction of
nitrous acid on aniline :

Aniline. Carbolic Acid.

Qjujk + NO 3 = HO, C 12 HJO + 2 N + HO.


Aniline acts powerfully upon the hydriodic ethers of the
different alcohols, in the manner already explained (1027), and
yields derived bases, such as ethylaniline [(C 4 H 6 , C 12 H 5 , H)N.]
When mixed with the oxychlorides, or with the anhydrides, of the
organic acids, aniline yields compounds which correspond with
the amides. With acetic oxychloride, for instance, it produces
acetanilide, and hydrochlorate of aniline :

Acetic Oxychloride. Aniline. Acetanilide. Hydrochlorate of Aniline.

3(C 12 H 7 N) = C 12 H. N + C 12 H 7 N,HC1

Aniline forms anilidated acids, anilides, dianilides, and aniles. The
aiiiles correspond to the imides of the ammonia group ; they con-
tain the elements of i equivalent of a dibasic acid and i equivalent
of aniline, minus 4 equivalents of water. The anilidated acids,
which correspond to the amidated acids, are formed from i equi-
valent of a dibasic acid and one of aniline, with the separation of
2 equivalents of water. The compounds enumerated in the follow-
ing list afford examples of each of these classes of substances :


Formanilide ...... C 12 H 5 , HN, C 2 H O 2

Benzanilide ...... C 12 H 5 , HN, C 14 H 5 O 2

Cinnamanilide ..... C 12 H 5 , HN, C 18 H 7 O 2

Oxanilide ...... 2(C 12 H 5 ), H 2 N 2 , C 4 O 4

Succinanilide ..... 2(C 12 H 5 ), H 2 N 2 , C 8 H 4 O 4

Suberanilide ..... 2(C 12 H 5 ), H 2 N 2 , C 16 H 12 O 4

Anilidated Acids.

Sulphanilic acid .... HO, C 12 H 5 , HN, S 2 O 5
Oxanilic acid ..... HO, C 12 H 5 , HN, C 4 O 5
Succinanilic acid .... HO, C 12 H 5 , HN, C 8 H 4 O 5
Camphoranilic acid . . . HO, C 12 H 5 , HN, C 20 H 14 O 5

Succinanile ...... C I2 H 5 N, C 8 H 4 O 4

Camphoranile ..... C 12 H 5 N, C 20 H 14 O 4

Aniline combines directly with cyanogen, and forms a feeble
jase, termed cy aniline (C 14 H 7 N 2 ), which contains the elements of
i equivalent of aniline and i of cyanogen. It is very unstable.



Aniline is remarkable as yielding compounds possessed of
basic properties, when portions of the hydrogen are displaced by
chlorine or by bromine. These compounds are best obtained by
decomposing chlorisatin, dichlorisatin, and trichlorisatin, by means
of hydrate of potash (p. 41).

ChloranUine (C 12 H 4 C1, H 2 N) is a weaker base than aniline,
and is obtained in white, fusible, volatilizable, crystalline needles ;
its salts have a strong disposition to crystallize ; and, like those
of aniline, they impart a yellow colour to a slip of deal. Dichlora-
niline (C 12 H 5 C1 2 N) is still less basic in its characters than the
foregoing substance ; and trichlor aniline (C 12 H 4 C1 3 N) is a very
volatile crystalline compound, which is entirely devoid of basic
properties. The corresponding compounds with bromine, in gene-
ral properties closely resemble the chlorinated forms of aniline.

The action of chlorine in these cases is very interesting :
although the introduction of a single equivalent of this body into
the composition of aniline does not destroy the basic character,
yet the electro-negative power of chlorine is exhibited in the
diminution of the basic energy possessed by the new group, as com-
pared with that of aniline ; each successive addition of chlorine
weakening the basic property, until it disappears altogether in

Dr. Hofmann, by whom these bases were discovered, has also
succeeded, in conjunction with Dr. Muspratt, in preparing a com-
pound which is termed nitraniline , C 12 H 4 NO 4 , H 2 N ; this body also
forms salts with acids; it contains an equivalent of peroxide of
nitrogen in the place of an equivalent of hydrogen. Its basic
properties are, however, very feeble.

Hofmann represents aniline as phenylamine, or a derivative of
ammonia, in which T equivalent of hydrogen is displaced by a
hydrocarbon C 12 H 5 , termed phenyl. Neither phenyl nor its iodide
have as yet been isolated ; but aniline may be procured by heating
hydrated carbolic (phenic) acid in a sealed tube with ammonia :

Phenic Acid. Aniline.

O + H 3 N = 2 HO ^HN

(1065) Several other oily bases have been discovered, homolo-
gous with aniline ; forming part of a series, each member of which
differs from the succeeding one in containing one equivalent more
of the carbo-hydrogen (C 2 H 2 ). The bases of this class may be
obtained from a series of hydrocarbons, of the form (C W 1I W _ 6 ).
These hydrocarbons when treated with nitric acid yield substitution-



C 18 H 12

Nitro-substitute (C n H n _ 7 NO 4 )

Base (C M H M _ & N)

Nitroxylole .

c'^ 4

^14 "7 -Wv/4

C 16 H 9 N0 4
C 18 H U N0 4
C 20 H 13 N0 4

Xylidine .
Cumidine .
Cymidine .

C 12 H 7 N


C 20 H 15 N

compounds, in which one equivalent of hydrogen is displaced by
one of peroxide of nitrogen (NO 4 ) ; and from this nitro-compounci,
the corresponding base may be obtained by Zinin's process with
hydrosulphate of ammonia (1062) :

Hydrocarbon (C M H,,_ 6 )

1. Benzole .

2. Toluole .

3. Xylole .

4. Cumole .

5. Cymole .

These bases of the aniline series belong to Hofmann's class of
amidogen bases, one equivalent of hydrogen having been displaced
by the hydrocarbons, C 12 H 5 , C 14 H 7 , C 16 H 9 , &c. ; they still retain
two equivalents of hydrogen in a form susceptible of displacement
by an equal number of equivalents of the alcohol radicles.

(b) Pyridine Bases (CJl n _ 5 ) N.

(1066) A series of bases, however, exists, each member of
which is metameric with one of those belonging to the aniline
group : but in the alkaloids of this class, none of the hydrogen
admits of displacement by the alcohol radicles ; consequently they
must be regarded as belonging to Hofmann's subdivision of nitrile
bases. They boil at a lower temperature than the corresponding
bases of the aniline series. These compounds have been principally
investigated by Anderson, and by Greville Williams. They are
furnished by the destructive distillation of a bituminous shale from
Dorsetshire ; and many of them are also contained in the products
of the distillation of bones, and of pit- coal. The following table
exhibits the metameric pairs of the aniline and pyridine groups :

Aniline series.

Pyridine series.










C 10 H 5 N

c X N









S 88



C 16 H n N

C 18 H 13 N











The bases of the pyridine series correspond to ammonia in
which the three equivalents of hydrogen have been displaced by
i equivalent of a hydrocarbon, such as (C 10 H S ) or (C 12 H 7 ) ; each
of these hydrocarbons constitutes a triatomic group, corresponding

s 2


to three equivalents of hydrogen : none of the hydrogen in these
hydrocarbons admits of displacement by the alcohol radicles, but
Anderson has succeeded in obtaining from the pyridine series some
remarkable bases into the composition of which platinum enters.
These bases have the closest connexion with those obtained by the
action of ammonia on the chlorides of platinum (828). The two
platinum bases from pyridine are :

Platinopyridine = C 10 H 3 Pt N, or C 10 H 3 2 (JPt), N.
Platosopyridine = C 10 H 3 Pt 2 N.

In the first of these compounds two equivalents of hydrogen in
the hydrocarbon C 10 H 5 , have been displaced by one equivalent of
platinum, which here performs the function assigned by Gerhardt
to platinicum (pt., eq. 49, see note to 828) ; whilst in the
second compound the two equivalents of hydrogen are displaced
by two equivalents of platinum, the metal here discharging the
function assigned to it by Gerhardt as platinosum (Pt., eq. 98).
Picoline yields similar compounds with platinum.

When the alkaloids of the pyridine group are treated with
iodide of ethyl, compounds are formed belonging to the class of am-
monium bases. Anderson has thus obtained iodide of ethylopyri-
dium (C 10 H 5 , C 4 H 5 N, I), and iodide of ethylopicolium (C 12 H 7 ,
C 4 H 5 N, I). The hydrated oxides, procured by acting upon these
compounds with oxide of silver, are not volatile, and are strongly

Picoline (C 12 H 7 N) is the best known base of the series to
which it belongs. It is usually extracted from coal tar or from
Dippel's oil (a product of the destructive distillation of bones), by
treating it with hydrochloric acid, and distilling the hydrochloric
solution with lime. The volatile bases which pass over are sub-
mitted to fractionated distillation, collecting separately those parts
which come over at about 270. Picoline is also obtained Mhen
piperine (1082) is distilled with hydrate of potash. Picoline is a
colourless, very mobile, oily liquid, of a penetrating odour. It is
lighter than water (sp. gr. 0*955), and boils at 271. It is gra-
dually volatilized by exposure to the air, and it does not, like
aniline, become brown under these circumstances. By this fact,
as well as by its lower boiling point, and smaller density, picoline is
at once distinguished from aniline. Picoline is soluble in water
in all proportions. It is not coloured violet by chloride of lime,
and is not affected by the addition of chromic acid to its solutions.
The salts of picoliue crystallize with difficulty, and many of



them are deliquescent. The hydro-chlorate forms deliquescent

(c) Quinoline series of Bases, (C tt H tt _ n ) N.

(1067) I* 1 addition to the members of the aniline and pyridine
series, coal tar contains a third series of bases of which quinoline
is the most important member. Three bases of this class are
at present known, viz. :

Quinoline. . . C 18 H 7 N
Lepidine . . . C 20 H 9 N
Cryptidine . . C 22 H n ]N"



/ '


5 IO



They combine with the hydriodic ethers, and form compounds
corresponding to ammonium; quinoline, for instance, yields with
iodide of ethyl an iodide of ethyloquinolium (C 18 H 7 , C 4 H 5 ,N, I).
These compounds, therefore, like those of the pyridine group,
belong to the class ofnitrile bases.

Quinoline or Leukol (C 18 H 7 N), Sp. gr. of liquid 1*081, of vapour
4*519. This alkali is readily obtained by decomposing cinchonia
with hydrate of potash : the resinous mass which is separated
under the name of quinoidine, during the preparation of the salts
of quinia, also yields it by similar treatment. Fragments of the
hydrate of potash are placed in a tubulated retort, moistened with
a few drops of water, and powdered cinchonia is added in small
quantities at a time ; on applying heat., the new base passes over,
accompanied by free hydrogen; if the product be redistilled, an
aqueous solution of ammonia with portions of the base pass over
first, and the latter portions consist of nearly pure quinoline, which
may be rendered anhydrous by a second rectification, after it has
stood for some days upon chloride of calcium.

Quinoline is a colourless oil of high refracting power ; it has a
disagreeable penetrating odour, and a bitter acrid taste. It remains
liquid at 4. At 464 it boils, emitting a vapour which burns
with a smoky flame. When exposed to the air it slowly becomes
converted into a resinous mass. If dropped upon paper it leaves a
greasy stain, which quickly disappears. It is dissolved sparingly
by water, but it is soluble in all proportions in alcohol, ether,
wood spirit, and bisulphide of carbon, as well as in the fixed and
essential oils. The nitrate, the oxalate, and the bichromate of
quinoline, crystallize with facility ; many double salts of quinoline,


such as those which it forms with platinum, gold, palladium, and
cadmium, may be obtained in beautiful crystals. The platinum
salt is nearly insoluble in water.

A fourth series of bases, provisionally termed pyrrol bases by
Anderson, is contained in DippeFs oil : they have been but incom-
pletely examined, but are characterized by yielding a red resinous
matter when decomposed. Anderson regards them as bases of
the pyridine series, coupled with the body which occasions this
red colour.

2. Bases produced by the action of Ammonia on Essential Oils.

(1068) During the process of obtaining formic acid by dis-
tilling bran or oatmeal with peroxide of manganese and dilute
sulphuric acid, a small quantity of an essential oil distils over, which
may be purified by redistillation. To this body the name offur-
furole (C 10 H 4 O 4 ) has been given. When pure it is colourless, but it
quickly becomes brown by exposure to the air. It has a fragrant
odour, somewhat resembling that of bitter almonds. It has a sp.
gr. in the liquid form of i'i68, and in vapour of 3 '34. Furfurole
boils at 323; it is dissolved by cold sulphuric acid, forming a
beautiful purple liquid, from which on dilution with water the
oil is separated unchanged. If mixed with solution of ammonia
in the cold, furfurole is gradually converted into a solid yel-
lowish-white insoluble mass, 3 equivalents of furfurole reacting
upon 2 equivalents of ammonia, while 6 of water are separated ;
3(C 10 H 4 O 4 ) + 2H 3 N = 2(C 15 HA)+6HO. This new compound
belongs to the class of hydramides (1050), it has been termed
furfuramide. Acids immediately decompose it, a salt of ammonia
is formed, and the oil is set at liberty. When boiled with
potash, however, no ammonia is evolved ; the substance is com-
pletely dissolved, and the solution on cooling deposits long silky
needles of a powerfully alkaline base which is isomeric with

Furfuria or furf urine (C 30 H 12 N 2 O 6 ), as this base has been
named, is inodorous and sparingly soluble in water; alcohol and
ether dissolve it freely. It melts below 212 to an oily-looking
liquid. It is dissolved by dilute acids, and completely neutralizes
them ; on adding ammonia to these solutions, the alkaloid is
precipitated unchanged. Its salts have a bitter taste ; they have
been used medicinally, with success, as substitutes for those
of quinia (Gregory).


Benzoline or amarine (C 42 H 18 N 2 ) . When a solution of ammonia
is allowed to remain for some days in contact with pure hydride of
benzoyl (essential oil of bitter almonds), a reaction occurs analogous
to the foregoing one with furfurole ; the mixture gradually becomes
converted into a crystalline mass of hydrobenzamide ; this sub-
stance is soluble in alcohol,, but insoluble in water. If boiled
with a solution of potash it assumes the appearance of a resin,
and becomes changed into benzoline, which is a base isomeric
with hydrobenzamide. The same change occurs if hydrobenzamide
be simply heated for some time to a temperature between 250
and 265. If the mass which is obtained by either of these
methods be treated with boiling alcohol, it is dissolved, and the
solution on cooling deposits the base in brilliant transparent four-
sided prisms, which are fusible below 212. Benzoline is nearly
insoluble in water, but it is readily dissolved by both alcohol and
ether. Its salts, with the exception of the acetate, are sparingly
soluble, and have an intensely bitter taste. When benzoline is
submitted to destructive distillation, a new base, pyrobenzoline,
or lophine (C 42 H 17 N 2 ), is formed, amongst other products.

3. Bases containing Electro-negative Radicles of the

(1069) It will be unnecessary to allude further to the fifth and
sixth methods (p. 255) of the formation of bases by the substitution
of the alcohol radicles for the hydrogen in ammonia and phos-
phuretted hydrogen, since this part of the subject has been already
fully examined (1027, et seq.) ; but it is an interesting circum-
stance, that bases may also be obtained which contain the electro-
negative hydrocarbons (C n H n _ 1 ) in the place of hydrogen. For
example, Natanson (Liebig's Annalen, xcii. 48, and xcviii. 291),
has succeeded in preparing a substance which he terms acetylamine,
(acetylia) ; this body is a derivative from ammonia, but it contains
an equivalent of Liebig^s electro-negative radicle acetyl (C 4 H 3 ),
in the place of one equivalent of hydrogen ; acetylia being
(C 4 H 3 , H 2 N = C 4 H 5 N) ; the same chemist has likewise isolated a
compound corresponding in composition to hydrated oxide of
ammonium; this new base may be termed hydrated oxide of
acetyliwn, C 4 H 3 , H 3 N, O.HO.

Acetylium.When Dutch liquid (C 4 H 3 C1, HC1) is heated for
some hours to a temperature of 300 in a sealed tube, with about 5
times its bulk of a concentrated solution of ammonia, it is com-
pletely decomposed ; a yellow liquid is formed, and crystals of chlo-


ride of ammonium are deposited in abundance : if these be separated
by nitration through muslin, and the mother liquor be treated with
oxide of silver, it yields a decidedly alkaline solution, which absorbs
carbonic acid from the air. The new base thus obtained is not
volatile, its salts have a feebly acid reaction, and do not crystallize.
If its chloride be mixed with a solution of bichloride of platinum
it yields a wax-like mass, which has the composition of the double
chloride of platinum and acetylium (C 4 H 3 , H 3 NC1, Pt C1 2 ) . Chlo-
ride of acetylium, if slightly acidulated with sulphuric acid and
mixed with nitrite of silver, furnishes aldehyd in abundance :

Chloride of Acetylium. Aldehyd.

C^THsNCl + AgO, NO 3 = C^O,~HO + 2 N + 2 HO + AgCl.

This reaction corresponds to that of nitrous acid on ethylia, by
which alcohol is reproduced whilst nitrogen and water are

The formation of this compound oxide of ammonium, in which
three out of the four equivalents of hydrogen in ammonium are
retained, is certainly a very remarkable circumstance, and it
affords one of the strongest arguments in favour of the ammonium
theory. It also strengthens the probability that olefiant gas is a
hydride of acetyl (C 4 H 3 , H) . It may be remarked that hydrated
oxide of acetylium is metameric with aldehyd-ammonia, although
so different from it in properties :

Hydrated Oxide of Acetylium. Aldehyd-ammonia.'

C^H^NO, HO = CJIA, NH 3 .

Online LibraryWilliam Allen MillerElements of chemistry: (Volume 3) → online text (page 28 of 93)