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Патент USA US2410820

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Patented Nov. 12,1946
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UNi'i‘ED STATES PATENT OFFHQE
PRODUCTION or VINYL CYANIDE
Charles R. Harris, Lockport, N. Y., assignor to E. I.
du Pont de Nemours & Company, Wilmington,
Del., a corporation of Delaware
No Drawing. Application January 12, 194.4,
\
I
SerialNo. 518,013
'1 Claims.
1
This invention relates to the production of
.
(Gl. 260-464)
,
‘
2
. Example
vinyl cyanide and has as its object a novel meth
A vertical stainless steel tube provided with an
od for producing this chemical.
In accordance with my invention, I_ subject
\ inlet at the top and an outlet at the bottom was
succinonitrlle vapor to pyrolysis at a tempera- 5 arranged to be heated in an electric furnace.‘
A layer of small porcelain Raschig rings was
ture within the range of about 300-‘700° 0., whereplaced in the bottom of the tube to serve as a
by I have discovered that vinyl cyanide is formed
support for any desired layer of catalyst. Above
in good yield by the following reaction:
_ the catalyst was placed a three-inch layer (75,
cc.) of glass beads. When no catalyst was used,
_,
CNCECHQCN CBwHCN-I-HCN
The reactionis endothermic,
10- the glass beads rested on the Raschig rings. A
,
thermocouple was provided for measuring the
In a preferred mode of practicing my inven-
temperature in the catalyst layer.
tion, succinonitrile is heated to form vapor which
In operation the tube was heated to an inside
is passed through a heated reactor or passed over 15 temperature of 300 to 700° 0-, and a slow stream
any suitable heated surface. If desired, a catof molten succlnonitrile was introduced in the
I alytic surface may be used, for example, a, cartop of the tube onto the glass beads. The suc
bonaceous material such as coke, charcoal‘ or ‘ einonitrile was rapidly vaporized on contact with
activated carbon, or alumina, silica gel or the
the hot glass beads, and the vapors were immedi
like. I have also found that alkali metal cy- 2o ately Subjected to the pyrolyzing temperature.
anides act as catalysts‘ for the reaction. These
The suceinenitrile vapors were diluted with by
may be supported on granular, infusible solids
drogen which was introduced in the to!) 0f the
such as charcoal or the other solid materials
mentioned above. For this purposeI may use the
reaction tube, above the glass beads. In a series
-0f runs the following catalysts were used:
cyanides of sodium, potassium, lithium, cesium, 25
or rubidium, or mixtures thereof. Preferably,
Run
Catalyst
I use a mixture of sodium and potassium cyanide
containing not less than 10% of either one.
Also
I prefer to carry out the pyrolysis reaction at a
’
A ------ -- 300 cc. Melamine pellets.
B """ " 30210:gtgfgou?ilgggeugiggiliglrggggdegovggggcgggght
temperature between the melting point of the 30 G ______ __ 75 cc. of 4-8 mesh size wood charcoal impregnated with
about 15% by weight of a 50-50 mixture of sodium and
cyanide or cyanide mixture and about 700° C. I
potassium cyanides.
have obtained my best results by using glowed
wood charcoal which has been impregnated with
an alkali metal cyanide.
12.5 cc. of the catalyst ofrun 0.
it; cc. of wood charcoal, 4-8 mesh size.
_
one.
~
However, excellent yields may be obtained
without the use of any catalyst, especially “at
temperatures of 500-650° 0. Some formation of
\
Do.
'
150 cc. of the catalyst of run 0.
The following results were obtained:
-
‘vinyl cyanide will occur when the succinonitrile is
pyrolyzed at temperatures as low as 300° 0., but
;
below this temperature the yield becomes too low 40 Run
giffligglgt'
_
summon.
Kigali“ tegelfgaiggm
to be of commercial importance. I prefer not
to exceed a temperature of about 700° C. to avoid
excessive, undesired decomposition reactions.
I prefer to carry out the reaction in‘tlie presence of an inert diluent gas such as h drogen or
nitrogen. Such gas may be mixed with suc-
.
era/mm.
232
315
cinonitrile vapors and the vapor-gas mixture.
subjected to the pyrolyzing temperature, or the
gas may be separately introduced into the reac
tion space. The amount of‘ diluent gas may be 60
varied over a‘ Wide range- 9- g" from 10% to 90%
63%‘;
vinylcyanide'
315
Cumin.
° 0.
Percent
- i;%
gag
‘33;;
1:00)
6%
525
Mg
3%,
1,%
W58
23.2
None
550.590
72:9
16mm.
l. A process for the production of vinyl cy
by Wlume °f the vamr‘ga‘s mixture' ordmm'?yanlde which comprises subjecting succinonitrile
8' mixture of about 50% (1111161115 8&8 is Preferredvapor to pyrolysis at a temperature of about 300
The following example further illustrates my 55 to 700" c. in the presence of a catalyst compris
invention:
in: an alkali metal cyanide on a solid support.
2,410,820
3
2. A process for the production or vinyl cy
anide which comprises subjecting succinonitrile
vapor to pyrolysis at a temperature of about 300
to 700° C. in the presence of a catalyst compris
ing charcoal impregnated with at least one alkali
metal cyanide.
‘
4
5. A process for the production or vinyl cy
anide which comprises subjecting succinonitrile
vapor together with an inert gas to pyrolysis at
a temperature or about 300° C. to 700° C. in the
presence or a catalyst comprising an alkali metal
cyanide on a solid support.
6. A process for the production or vinyl cy
3. A process for the production of vinyl cy
anide which comprises subjecting succinonitrile
anide which comprises subjecting succinonitrile
vapor together with hydrogen to pyrolysis at 'a
vapor to pyrolysis in the presence of a catalyst
comprising a. carbonaceous support impregnated 10 temperature or about 300° C. to 700° C. in the
presence of a catalyst comprising an alkali metal
with at least one alkali metal cyanide at a tem
cyanide on a solid support.
perature within the range of about 300 to 700° C.
'7. A process for the production of vinyl cy-'
which is above the melting point of said cyanide.
anide which comprises subjecting succinonitrile
4. A process for the production of vinyl cy
anide which comprises subjecting succinonitrile 15 vapor together with hydrogen to pyrolysis at
a temperature 01' about 500° C. to 650° C. in the
vapor to pyrolysis in the presence or a catalyst
presence of a catalyst comprising an alkali metal
comprising charcoal impregnated with a mixture
cyanide on a solid support. _
of sodium and potassium cyanides at a tempera
ture within the range or 500 to 650° C. which is
CHARLES R. HARRIS.
above the melting point of said mixture.
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