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Патент USA US2387287

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Oct; 23, 1945.
2,387,287
D. B. PALL I
METHOD FOR PRODUCING SODIUM CYANIDE
Filed July 9, 1942
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INVENTOR
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041/10 .9.
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FALL
RNEY
Patented Oct. 23, 1945
' 2,381,287
UNITED STATES PATENT-caries
2,387,287
METHOD FOR PRODUCING SODIUM
CYANID E
'
David B. Pail, New York, N. Y., assignor to Inter
chemical Corporation, New‘ York, N; Y., a cor
poration of Ohio
Application July 9, 1942, Serial No. 450,257
2 Claims. (GI. 23-82)
This invention relates to gas reactions, and
necessary, a puri?cation system 2i is provided.
aims to provide a simple and economical method
and apparatus for the circulation of gaseous re
prior to the entrance of the gas into the reaction
chamber 22. After the reaction, the gas passes
actants, characterized by low operation cost, econ
into the exhaust tube 23, through an optional
omy in the use of gaseous reactants, and the
' stripping system 24, and into the aspirator
unique ability to handle highly corrosive gases
with a minimum of corrosion.
through the gas intake i'i.
, '
Obviously, the liquid i2 should not be such
'
In prior art methods involving gaseous react
ants, the gases emerging from the reaction chamf
her have either been vented, directly or after
stripping of solidi?able lique?able and adsorbable
components when the reactant is relatively cheap,
or have been elaborately puri?ed, and pumped
back into the system, whenever the gaseous re
actant was su?iciently expensive to pay for the 15
cost of recovery. Corrosive gases have been espe
a powerful solvent for the gas that it will not
release it; most preferably, in the case of cor
rosive gases, the liquid is one which will not pro
duce a. corrosive solution of the gas.
The treatment compartment it, the puri?ca
tion system 2!, and the stripping system 26 will
be changed or omitted, depending on the various
processes carried out in the system. In Fig. 2,
a speci?c utilization of the system for the Bucher
cyanide process (involving the reaction of iron,
cially hard to handle and diiilcult to control.
My invention is directed to a method and appa
carbon, soda ash and nitrogen) is disclosed.
In this application of the invention, the cir
such low cost that even relatively cheap gases 20 culating liquid I2 in the chamber ii is water,
can be economically recirculated; the problem of
and the gas circulated is nitrogen. The treatment
corrosion is also largely controlled. In my meth
compartment it is omitted, since it is unneces
ratus for‘recirculating gases, characterized by
od, a chamber is provided carrying a liquid which
sary. The circulation system is provided with a
may be a stripping liquid for the product of the
vacuum release iii and a pressure release H2
reaction chamber; the liquid is circulated from 25 to allow the discharge of exit gas which is in
the chamber through an aspirator and back into
excess of the fresh nitrogen requirements.
the chamber. The aspirator draws gas from the
In the reaction chamber 22, sodium carbonate‘,
exhaust end of the reaction chamber, into the
?nely dividediron, or iron oxide, and carbon,
liquid; the gas and liquid separate in the con
are reacted with pure nitrogen, to produce sodium
tainer, and the gas is forced into the reaction 30 cyanide and other solids, water vapor and car
chamber by the greater pressure in the container
bon monoxide, by heating the reactants to 940"
relative to that in the reaction chamber.
C. The mixture of excess nitrogen and carbon
My invention is also directed to the use of
monoxide produced, together with a small amount
the method and apparatus in the Bucher process
of sodium vapor and vaporized or suspended so—
for making sodium ferrocyanide.
85 dium carbonate, is passed through a. water trap
The invention can perhaps best be understood
2M before it is drawn back into the circulating
by referring to the accompanying drawing, in
system.
which—-
carbonate, dissolve in the circulating pump liq
.
'
Fig. 1 is a schematic layout of my new appa
ratus;
-
Fig. 2 is a schematic layout of the apparatus
speci?cally designed for the Bucher process.
Referring to Fig. 1, a chamber ii is provided
containing a liquid l2. It has a liquid discharge
Suspended solids, particularly sodium
uid, without clogging the pump.
The nitrogen and carbon- monoxide mixture
passes out of'the chamber it through the gas
exhaust i8, which is provided with a sampler ml
to permit of analysis of the exhaust gas. Com
pressed air, in amounts calculated as indicated
45 below, is .fed into the stream, at the intake 20;
ment compartment it (although this may be
a flow meter 2!“ is provided to measure the
eliminated) and a pump [5 through a ventum
amount introduced. The mixture of air, nitrogen
} port l3 which carries the liquid through a treat
aspirator tube i6 and back into the chamber.
and carbon monoxide is then passed through the
puri?cation system comprising ?rst a tube 2H,
system; it draws gas into the system at the gas 50 packed with a mixture of copper and cupric oxide
intake of the aspirator i1, and discharges it
catalyst, heated to about 500° C. Here the car
through the opening I8 in the chamber Ii, over
bon monoxide is oxidized to carbon dioxide, and
the liquid level.
the mixture is then passed through a device for
The gas from the chamber passes into a tube
removing CO2. This may be done by liquefaction
is, provided with an intake 20 for freshgas; if 53 or absorption in water under pressure in large
The liquid is continuously circulated through the
2
2,887,287
scale work; in the drawing, a laboratory technique
is used which comprises bubbling the gas through
NaOH solution in bottles ii! to absorb the (70:.
The nitrgoen is dried by dehydrating tubes or hot
tles 2H,.contalning sulfuric acid or other dehy
drating agents. A ?ow meter 2H1 measures the‘
?ow of puri?ed nitrogen into the reaction cham
ber 22.
The carbon monoxide is removed by the simple
oxidation of O0 to CO: with the calculated
amount of oxygen supplied from the air. This
amount can be calculated from the formula:
5X pure nitrogen ?ow rateX
onitrile is recovered by introducing a ?lter into
the treatment compartment H.
Obviously, my method oi’ circulating gases may
be widely applied to other chemical processes
with similar good results.
I claim:
1. In the method of producing sodium cyanide
by the reaction of carbon, sodium carbonate and
pure nitrogen, the steps which comprise pass- '
ing pure nitrogen into a reaction chamber con
taining carbon, sodium carbonate and an iron
bearing material heated to reaction temperature,
withdrawing the mixture oi.’ nitrogen and car- ‘
bon monoxide formed through an aspirator in
2 (CO concentration in exhaust+ l) 15 which water is the circulating ?uid, so that en
trained sodium carbonate is removed from the
The nitrogen added in the air more then re
gas, adding just sufficient air to oxidize the
places that absorbed in the reaction; the excess
carbon monoxide to carbon dioxide, passing the
is exhausted through the pressure or vacuum re
carbon monoxide/nitrogen/air mixture through
lease valves.
20 a copper oxide catalyst to heat it to about 500°
In this process, the system has the advantage
C‘. to convert the carbon monoxide and oxygen
of permitting the use of the necessary large ex
in the air to carbon dioxide, decarbonating and
cesses of nitrogen economically, without the ne
dehydrating the gas thus formed, and passing
cessity for recovering huge quantities of ni
the pure nitrogen resulting back into the reac
trogen from air.
a
25 tion.
The apparatus and method may be used for
2. In the method of producing sodium cyanide
other reactions. Thus, in the catalytic vapor
by the reaction of carbon, sodium carbonate and
phase reaction of phthalimide and ammonia to
pure nitrogen, the steps which comprise pass
produce .phthalonitrile, important economies can
be effected by my method. The circulating gas 30 ing pure nitrogen into a reaction chambericon
taining carbon, sodium carbonate and an iron
in this instance is ammonia; the circulating liq
bearing material heated to reaction temperature,
uid is saturated ammonia water. Phthalimide
withdrawing the mixture of nitrogen and carbon
and any fresh ammonia needed are introduced
monoxide formed, together with entrained im
into the apparatus at 20, to join the stream of
ammonia which goes directly into the reactor 35 purities, through a pumping system containing
a liquid which removes the entrained impurities
with the elimination of the puri?cation system
from the gas as it passes through the liquid,
2|. From the reactor, the gaseous reaction mix
adding just sufiicient air to oxidize the carbon
ture passes directly into the aspirator, with the
monoxide to carbon dioxide, passing the carbon
stripping system 24 being eliminated. The re
action mixture of phthalimide, ' phthalonitrile 40 monoxide/nitrogen/air mixture through a cop
per oxide catalyst to heat it to about 500° C. to
and ammonia is thoroughly mixed with the con
centrated ammonia water. The phthalimide dis
convert the carbon monoxide and oxygen in the
solves, the phthalonitrile precipitates, the am
air to carbon dioxide, decarbonating and dehy
monia passes off as a gas for recirculation. The
drating the gas thus formed, and passing the
phthalimide can be recovered from the ammonia 45 pure nitrogen resulting back into the reaction.
water by tapping a portion or it oil; the phthal
DAVID B. PALL.
Air iniiow=
CO concentration in exhaust
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