1,672,253
June 5, 1928.
l. V. GILES
METHOD OF MAKING AROMATIC NITRILES
Filed Aug. 25, 1926
I
l?AAc V.. G was.
INVENTOR
BY
ATTORNEY
1,672,253
' Patented June 5, 1928',
UNITED STATES PATENT
‘OFFICE.
ISAAC V. ‘GILES. OF ELIZABETH, 'NEW JERSEY, ASSIGJOR TO AMERICAN CYANAMID ~
COMPANY, OF NEW YORK, N. Y., A CORPORATION OF MAINE.
,
METHOD OF MAKING AROMATIC NI'I‘BILES'.
Application ?led August 25, 1926. Serial N'o. 181,404.
This invention relates to the production of hours and in many cases the reaction is com
in one and one-half to two hours.
nitriles, more particularly to the manufac plete
The single ? ure of the accompanying
ture of aromatic nitriles and derivatives
drawing is an e evational view of a simple
5 A method has been proposed for the pro form of apparatus which I have used to
duction of aromatic nitriles in which a chlor carry out my new method.
The reaction vessel '1 is usually of tubular
derivative of an aromatic hydrocarbon was
shape
and may be constructed of extra heavy
caused to react with a heavy metal cyanide at.
thereof.
‘
55
A
elevated temperatures and pressures. For iron pipe of suitable diameter, preferably
10 instance, in the manufacture of benzonitrile, lined with a copper sheath, andit may be in r
a mixture of chlorbenzol and a cyanide, such a horizontal or slightly inclined position. 65
as copper cyanide, zinc cyanide, calcium One end thereof is permanently closed by ‘a
ferrocyanide, potassium ferrocyanide or cop
cap 2 which is welded into place and a stub .
er ferrocyanide was made and the mixture shaft 3 secured thereto rotates in bearing 4.
15 either with or without an organic solvent The opposite end of reaction vessel 1 is
was heated to a relatively high temperature closed by a cap 5 threaded into place and
a pressure gauge 6 ?tting into the
for a predetermined. period of time, gener having
same by means of hollow shaft or tube '2"
ally from. 8 to 20 hours.
70
In most cases the
reaction was incomplete except where copper which operates in bearing 8. The reaction
2° cyanide was used and in some of the cases vessel is heated by a series of burners 9
in proximity thereto and a shield 10
the amount of conversion into benzonitrile placed
surrounding
the reaction vessel and burners 75
was almost negligible. Furthermore the
retainsthe
heat
and so aids in obtaining the
‘ cyanides used for the reaction are compara
desired
uniform
temperature in the reaction
tively expensive and for these reasons the
vessel.
A
thermometer
11 assing throu h
2-5 process was not hitherto commercial.
the
shield
10
is
used
for
etermining t e
The present invention is intended to obvi
80
ate the di?iculties encountered in the pro temperature of the space within the shield
which
closely
approximates
the
temperature
duction of organic nitriles from a chlor
compound and a cyanide, it being among the within the reaction vessel itself. A pulley
30 objects thereof to devise a method whereby 12 ?xed on shaft 7 is connected by means of
the reaction may be caused to take place a belt 13 to a motor 14 which is adapted to
cheaply and readily and wherein the reaction slowly. rotate the reaction vessel to mix the
goes substantially to completion.
ingredients therein.
85
,
In practicing the invention I may make
In pincticing my invention I utilize sim
a
mixture
containing, speci?cally, e ual mo
35 ple, soluble cyanides such as of the alkali
or alkali earth metals, which class of com lecular parts of sodium cyanide an copper
which is charged into the reaction
pounds I term alkali-forming metal cyanides. ‘cyanide,
I mix with the alkali-forming metal cyanide vessel-31 through the opening obtained by
an amount of copper cyanide which is gen removing cap 5 and a suitable amount of
“ erally less than the alkali-forming metal chlorbenzol is placed therein, the cap 5 is
into place and the apparatus
cyanide, add the mixture to a chlor deriva threaded
caused
to
rotate
by actuation of the motor
tive of a suitable compound, such as chlor
14 and pulley 12. The burners 9 are lighted
benzol, and heat the same in a closed vessel vand
in a short time the reaction vessel
under pressure for a suitable length of time,
45 generally less than six hours, at a tempera reaches the proper temperature for the re
ture of approximately 250° C. to 350° (1., action, which is allowed to take place for a
and a pressure of 15 to 30 atmospheres.’ predetermined period of time. I may utilize
The reaction goes substantially to comple '50 parts by weight of a mixture cone-Lining
tion, the length of time necessary for a com equal ‘molecular parts of sodium cyanide
and copper cyanide and add thereto 175
50 plete reaction varying with the type of mix parts
weight of chlorbenzol, seal the same
ture used and the temperature and pressure in thebyreaction
vessel and rotate the vessel
in the reaction vessel, but in all cases I find .
at
a
temperature
of 320° C. to 325° C. for
that the reaction requires no more than six
90
95
100
2
1,072,253
about six hours. The pressure within the results obtained. When a porous material is
vessel is maintained at 25 to 28 atmospheres. used, a speedier and more complete reaction
At the end of this time the vessel is cooled probably takes place, whereby I am enabled
and the benzonitrile formed in the reaction to use a very high proportion of sodium
is ‘separated from the other constituents. cyanide in the mixture.
All of the cyanide in the vessel has disap
I have also found that a crude cyanide
peared and the .yield' of benzonitrile is containing about 50 per cent calcium cyanide,
70
found to be 88 per cent of the theoretical. together with various impurities, such as
The remainder" represents loss by- leakage alkali or alkali earth metal salts, lime, car~
10
and iii-manipulation and the formation of a bon and others is also well adapted for use
small amount of tar.
-
'
75
. in the present method, the great advantage in '
I have found that the above described re the utilization thereof being the extreme
action may be promoted‘by the addition to cheapness of the raw ‘material. For ex
the reaction mixture of a portion of the ample, I have made a mixture of 3 molecu
15
residue obtained froma previous run. This lar parts of impure calcium cyanide in the
residue contains principally cuprous chlo form of ?akes with 1 molecular part of cop
ride which is formed as fol ows: _
80
per cyanide and a suitable amount of chlor
benzol which was heated to 330° C. at 24 to
27 atmospheres for six hours. Substantially
20
By the addition of a small amount of such all of the contained cyanide was converted
a material the reaction may be caused to and the yield of benzonitrile was about 87.5
take place at a lower temperature and pres per cent of the theoretical. Even higher
sure or in a shorter time. For instance, I
85
proportions of impure calcium cyanide may
have made a mixture of equal molecular be used in the method with equally good re
25
parts of sodium cyanide and copper cyanide sults, it being desirable, however, that the
with a suitable amount of chlorbenzol and
added an amount of cuprous chloride resi
due equal to from 10 to 20 per cent of the
cyanide present and heated the same to a
temperature of 260° C. to 280° C. at'a pres
'30
calcium cyanide be in the form of ?akes or
granules rather than in the form of dust.
It would appear that a better or more com
plete reaction is obtained in this case when
the particles are of relatively large size.
sure of 20 to 23 atmospheres for about 51/2 ' The benzonitrile formed in this reaction
hours. The yield ‘of benzonitrile was in this may be redistilled from the other products
case about 86 per cent of the theoretical.
thereof and puri?ed in any suitable mail
I have been enabled to increase the pro ner and sold as such. However, I prefer to
portion of sodium cyanide in both mixtures convert the same either into benzoic acid or a
35
05
l 00
to a still greater proportion with excellent benzoate such as sodium. benzoate, which
results and have successfully used a mixture may be accomplished in a very simple and
containing 10 molecular parts of sodium ‘satisfactory manner. Benzonitrile may be
cyanide to one molecular part of copper readily hydrolyzed with sulphuric acid and
cyanide with a complete conversion and a the resulting benzoic acid’ may be sepa
. high yield of benzonitrile. However, I have rated from the' solution containing excess
found that the higher the proportion of sulphuric acid and ammonium sulphate. :
alkali-forming metal cyanide, the higher However, a simpler method consists in con
should be the temperature of the reaction ducting the hydrolysis with a caustic soda
vessel but this temperature should not ordi solution of 20 to 35 per cent or even less at 110
narily exceed 350° C.
'
It is not necessar
‘
ordinary pressure for a suitable time, gen-
to use a pure alkali
erally 2 to 3 hours, with the use of a‘ re?ux
forming metal cyanide in this process as I condenser. When the reaction is complete
have obtained equally as good results with the residue is solid sodium benzoate to
an impure cyanide as with a pure cyanide. which is added a su?icient amount ofv Water 115
For example, I have used a porous bri to dissolve the same, the solution being then
quetted sodium cyanide containing about 90 ?ltered to remove sediment and evaporated
per cent NaCN and derived from the residue to dryness, giving a very pure product.’ If
obtained in the manufacture 'of beet sugar a slight excess of caustic soda is used in the
55
and commonly known/as “beet cyanide”. hydrolysis it is desirable to add to the solu
A mixture containing" this material in the tion prior to the evaporation a sufficient
vmolecular proportion of ten parts to one amount of benzoic acid to combine with the
part of copper cyanide gave a complete con free caustic soda present, thus obtaining a
version and a yield of about 85 per cent of‘ product free from alkali.
the theoretical amount of benzonitrile. This
Although I have described my invention,
beet cyanide appeared to act more favorably setting forth several speci?c embodiments
120
125
than a purer cyanide which had been pro thereof and showing that sodium cyanide
duced in the fused state and I am inclined and calcium cyanide may be successfully
65
to believe that the physical condition of the used in the production of benzonitrile, my
cyanide used is an important factor in the invention is not limited to the speci?c com
130
1,672,253 '
metal cyanide, the latter beingh the
pounds mentioned. Other alkali and alkali forming
major
constituent
of the mixture, and _ eat
. earth metal cyanides may be substituted for
those mentioned, and in the claims I intend
ing the same.
~
50
4. A method of making aromatic nitriles
to include by theterm alkali-forming metal which
providing a halogenated
cyanides, the cyanides of the various alkali aromaticcomprises
hydrocarbon,
adding‘ thereto a
and alkali, earth metals. In lace of the
of copper cyanide and an alkali
erivatives of mixture
forming
metal cyanide, the relative pro
other aromatic hydrocarbons, of homologous portions thereof
one part copper cya
nature or containing other substituted nide to at least being
three parts alkali-formmg
groups. It is ‘not essential that copper metal cyanide, and
heating the same. '
chlorbenzol I may use chlor
10
cyanide be resent in the reaction mixture
5. A method of making aromatic nitriles
initially, an I have conducted my method which
providin a halogenated
by using a mixture of cuprous chloride’and aromaticcomprises
hydrocarbon, a ding thereto a
sodium cyanide ‘instead of a mixture of
c anides as set forth in the examples given
a ove, and by the term “00 per cyanide” as
used in the claims I inten to include not
60
mixture of, copper c anide and an alkali
forming metal cyani e, the latter being the
major constituent of the mixture and being
only copper cyanide but also mixtures which in particles of relatively large size, and heat
'
'
give rise to or have the same effect as cop-' ing the same.
6;
A
method
of
making
aromatic
nitriles
per cyanide. The proportions of the in which comprises providm a halogenated
gredients, the temperatures, pressures and aromatic
hydrocarbon, a ding thereto a
65
times of treatment are o'l'ven only for pur
and an alkali 70
poses of illustration and5 are not considered‘ mixture of copper c e,anide
the
latter
being the '
to he at all limiting as it is apparent that forming metal cyani
major
constituent
of
the
mixture
and
being
; these details may be varied within wide in the 'form of ?akes, and heating the same.
limits with excellent results. These and
7.- A method of making aromatic nitriles
other changes may be made in my invention, which
providin a' halogenated
the scope of which is de?ned in the claims aromaticcomprises
hydrocarbon, a ding thereto a
appended hereto.
30
What I claim is:
mixture of a cop er salt and an alkali-form
_
_
0 am e, and heating the same.
1. A method of making'aromatic nitriles ing-metal
\
8.
A
met
0d of making aromatic nitriles
which comprfses providin a halogenated
comprises providln a halogenated
aromatic hydrocarbon, adiding thereto a which
aromatic
hydrocarbon, a ding thereto a
mixture of copper cyanide and an alkali
36
of cuprous chloride and an alkali
forming metal‘ cyanide, and heating the mixture
forming metal cyanide, and heating the
same.
40
45
80
-
e.
2. A method of making aromatic nitriles‘ sam
9. A method of making aromatic nitriles
which comprises providing a halogenated which
comprises providin a. halogenated
aromatic hydrocarbon, adding thereto a mix
ture of copper cyanide and an alkali-form aromatic hydrocarbon, a ding thereto a
85
of copper cyanide, cuprous chloride
ing metal cyanide, the latter bein the major mixture
and
an'alkah-formmg
metal cyanide, and
eating
the
.
constituent of the mixture, and
heating the same.
'
I
same.
In
testimony
whereof,
I
have
hereunto
3. A method of making aromatic nitriles
which comprises providin a halogenated ' subscribed my name this 12th day of August, _
aromatic hydrocarbon, a ding thereto a 1926.
ISAAC V. GILES.
mixture of ‘copper cyanide and an alkali