CATALYSEUR ET REDUCTION CATALYSEE DU MONOXYDE DE CARBONE

CATALYST AND PROCESS FOR REDUCING CARBON MONOXIDE

Abrégé anglais

ABSTRACT OF THE DISCLOSURE:
Reduction of carbon monoxide by means of hydrogen
with the resultant formation of a mixture of hydro-
carbons having substantially from 1 to 4 carbon atoms
in contact with a catalyst containing iron or a
mixture of iron and copper as its catalytically active
ingredient, the catalyst being made by contacting one
or more complex salts of the following general formula:
Mex [Fe(CN)6]y
in which Me stands for an iron and/or copper-ion, x
stands for a number of 1 to 4, and y stands for a
number of 1 to 3, with hydrogen or a hydrogen/carbon
monoxide-mixture at about 200 to 500°C, under 1 to
100 atmospheres absolute and over a period of about
2 to 20 hours and thereby reducing the complex salts
substantially to elementary iron or copper.

Revendications

The embodiments of the invention in which an exclusive
property or privilege is claimed are defined as follows:
THE CLAIMS:
1) Catalyst containing iron or a mixture of iron and
copper as its catalytically active ingredient for
reducing carbon monoxide by means of hydrogen with
the resultant formation of a mixture of hydrocarbons
having substantially from 1 to 4 carbon atoms, said
catalyst being made by contacting complex salts of
the following general formula:
Mex [Fe(CN)6] y
in which Me stands for an iron and/or copper-ion, x
stands for a number of 1 to 4, and y stands for a
number of 1 to 3, with hydrogen or a hydrogen/carbon
monoxide-mixture at temperatures of about 200 to
500°C, under pressures of 1 to 100 atmospheres
absolute and over a period of about 2 to 20 hours
and thereby reducing the complex salts substantially
to elementary iron or copper.
2) Catalyst as claimed in claim 1, wherein the parameter
x stands for 2 or 4 and the parameter y stands for
1 or 3.
3) Catalyst as claimed in claim 1, the catalyst having
been made by contacting the complex salts with at
least stoichiometric proportions of hydrogen or a
hydrogen/carbon monoxide-mixture at temperatures of
350 to 400°C, under pressures of 5 to 50 atmospheres
gauge and over a period of 3 to 10 hours.
4) Catalyst as claimed in claim 1, having been made by
contacting the complex salts with-a hydrogen/carbon
monoxide mixture in a molar ratio of 3:1 to 2:1.
- 16 -

5. Catalyst as claimed in claim 1, the catalyst being
in the form of granules or pellets or being deposited on a carrier.
6. Catalyst as claimed in claim 3, wherein the carrier is
alumina, silicic acid, kieselguhr, asbestos, glass fibers, clay
minerals, pumice or active carbon.
7. Catalyst as claimed in claim 5, wherein about 20 to 95
weight % of catalytically active ingredient is applied to the
carrier, the percentage being based on the total weight of catal-
ytically active ingredient and carrier.
8. Catalyst as claimed in claim 1, wherein the complex
salts of the general formula are made by precipitating them from
an aqueous alkali metal ferrocyanide solution by means of an
aqueous solution of an iron and/or copper salt, and separating
and drying the precipitated salt.
9. In a process for the catalytic reduction of carbon
monoxide by means of hydrogen with the resultant formation of a
mixture of hydrocarbons containing substantially from 1 to 4
carbon atoms by contacting a carbon monoxide/hydrogen-mixture
at elevated temperature, at atmospheric or higher pressure with
a catalyst containing iron or a mixture of iron and copper as
its catalytically active ingredient, the improvement which
comprises: contacting the gas mixture containing hydrogen and
carbon monoxide in a molar ratio of 0.5 - 3:1 at temperatures of
about 200 to 500°C and under pressures of 1 to 100 atmospheres
absolute, with a catalyst, the gas mixture being used at a rate
of about 100 to 10,000 normal liter (S.T.P.) per liter of cat-
alyst per hour, and separating hydrocarbons having from 1 to 4
carbon atoms from the issuing gas, said catalyst having been made
17

by contacting complex salts of the following general formula:
<IMG>
in which Me stands for an iron and/or copper-ion, x stands
for a number of 1 to 4, and y stands for a number of 1 to 3,
with hydrogen or a hydrogen/carbon monoxide mixture at temper-
atures of about 200 to 500°C, under pressures of 1 to 100
atmospheres absolute and over a period of about 2 to 20
hours and thereby reducing the complex salts to elementary
iron or copper.
10. Process as claimed in claim 9, wherein the gaseous
mixture of hydrogen and carbon monoxide contacted with the
catalyst is used in a molar ratio of 0.8 - 3:1.
11. Process as claimed in claim 9, wherein the catalyst
is contacted at temperatures of 250 to 450°C under pressures
of 5 to 50 atmospheres gauge with 200 to 5000 liter of gas
mixture, per liter of catalyst per hour.
12. Process as claimed in claim 9, wherein the parameter
x stands for 2 or 4 and the parameter y stands for 1 or 3.
18

13) Process as claimed in claim 9, wherein the complex
salts of the general formula are contacted with at
least stoichiometric proportions of hydrogen or a
hydrogen/carbon monoxide mixture at temperatures
of 350 to 400°C, under pressures of 5 to 50
atmospheres gauge and over periods of 3 to 10 hours.
14) Process as claimed in claim 9, wherein the complex
salts of the general formula are contacted with a
mixture of hydrogen and carbon monoxide in a molar
ratio of 3:1 to 1:2.
15) Process as claimed in claim 9, wherein the catalyst
is used in the form of granules or pellets or is
applied to a carrier.
16) Process as claimed in claim 15, wherein the catalyst
carrier is selected from alumina, silicic acid,
kieselguhr, asbestos, glass fibers, clay minerals,
pumice or active carbon.
17) Process as claimed in claim 15, wherein about 20
to 95 weight % of catalytically active ingredient
is applied to the carrier, the percentage being
based on the total weight of catalytically active
ingredient and carrier.
18) Process as claimed in claim 9, wherein the complex
salts of the general formula are made by
precipitating them from an aqueous alkali metal
ferrocyanide solution by means of an aqueous
solution of an iron and/or copper salt, and
separating and drying the precipitated salt.
- 19 -

Description

1~73436
HOE 75/H 052
This invention relates to a catalyst containing iron
or a mixture of iron and copper as its catalytically
active ingredient, and to a process for reducing carbon
monoxide by means of hydrogen with the resultant formation
of a mixture of hydrocarbons containing substantially from
1 to 4 carbon atoms.
Ethylene is one of the most important lower hydro-
carbons which are used as starting materials in the
chemical industries for the commercial production of a
wide variety of secondary products. In view of the
considerable demand for ethylene, it is highly desirable
to exploit raw material sources other than petroleum for
making ethylene. One of such raw materials which recommend
themselves is water gas which is obtained by reacting coal
with steam at high temperatures.
The catalytic hydrogenation of carbon monoxide with
the resultant formation of hydrocarbons has been fully
described, for example, by Winnacker-Weingaertner in r
"Chemische Technologie", vol. Organische Technologie I,
pages 780-803, published by Carl Hauser Verlag, ~unchen,
19~2. This reaction entails the formation of all
hydrocarbons belonging to the olefin and paraffin series,
which are obtained in quite different proportions
depending on the particular catalyst and reaction
conditions used. It is more specifically stated at page
786 of the abo~e publication that in those cases in which
an iron or iron/copper-catalyst is substituted for a cobalt
catalyst in the hydrogenation of carbon monoxide, olefins
tend to be formed at an increasing rate while methane
- 2 -
~ .

1073436
- tends to be formed at a decreas'ng rate. The prior art
catalysts are so-called precipitation catalysts. They
are made, for example, by dissolving the metals in
nitric acid and rapidly precipitating them, while hot,
with an alkali metal carbonate solution. After
precipitation, the precipitate is filtered off, washed
out with water, dried at 110C, crushed and screened.
Next, the screened matter is reduced by contacting it
with hydrogen or synthetic gas at 225C under a
pressure of 10 atmospheres gauge.
The iron or iron/copper-catalysts prepared in the
manner just described have an unsatisfactory catalytic
- efficiency in the hydrogenation of carbon monoxide
inasmuch as the reaction gas contains an unsufficiently
low proportion of C2-C4 hydro-carbons, especially C2-
hydrocarbons. In other words, the catalysts are
insufficiently selective as regards the formation of
low olefinic hydrocarbons.
The present invention obviates the disadvantageous
effects referred to hereinabove and provides iron/
copper-catalysts which by reason of the specific method
selected for their preparation enable the proportion of
C2-C4 hydrocarbons in the reaction gas obtained on
hydrogenating carbon monoxide to be considerably
increased.
The present invention thus provides more
specifically a catalyst containing iron or a mixture of
iron and copper as its catalytically active ingredient
for reducing carbon monoxide by means of hydrogen with
the resultant formation of a mixture of hydrocarbons

1073436
having substantially from 1 to L~ carbon atoms, said
catalyst being made by contacting one or more complex
salts of the following general formula:
]
- in which Me stands for an iron and/or copper-ion, x
stands for a number of 1 to 4, and y stands for a
number of 1 to 3, with hydrogen or a hydrogen/carbon
monoxide-mixture at temperatures of about¦200 to 500C,
under pressures of 1 to 100 atmospheres absolute and
over a period of about 2 to 20 hours and thereby
reducing the complex salts to elementary iron or copper.
In the above general formula, the parameters x and
y stand more preferably for the numbers 2 and 4 or 1
and 3, respectively. The particular compounds concerned
in this case have approximately the following
constitution:
Fe4 Ee(CNj ~3, CuFe ~e(CN)~ , Cu2 ~e(CN)~ , Cu4 [e(CN)~
in which the water of hydration and residual alkali
metal contents remain unmentioned.
A preferred form of catalyst preparation comprises
contacting the complex salts with at least
stoichiometric proportions of hydrogen or a hydrogen/
carbon monoxide-mixture in a preferred molar ratio of
3:1 to 1:2 at temperatures of 350 to 400C, under
pressures of 5 to 50 atmospheres gauge, and o~er
periods of 3 to 10 hours.
With respect to the nature of the catalyst, it is
possible for it to be used in the form of granules or
, . ,-

1073436
pellets or to be deposited on a carrier, such as
alumina, silicic acid, kieselguhr, asbestos, glass
fibers, clay minerals, pumice or active carbon. In
those cases in which the catalyst is deposited on a
carrier, it is preferable for about 20 to 95 weight %
of catalytically active ingredient to be applied to
the carrier, the percentage being based on the total
weight of catalytically active ingredient and carrier.
The catalyst of the present invention is a precipitation
catalyst and it is accordingly possible to obtain the
complex salts of the above general formula by
precipitating them from an aqueous alkali metal ferro~
cyanide solution by means of an aqueous solution of an
iron andlor copper-salt, and separating and drying the
precipitated salt.
The present invention also provides a process for
the catalytic reduction of carbon monixide by means of
hydrogen with the resultant formation of a mixture of
hydrocarbons containing substantially from 1 to 4
carbon atoms by contacting a carbon monoxide/hydrogen-
mixture at elevated temperature, at atmospheric or
higher pressure with a catalyst containing iron or a
mixture of iron and copper as its catalytically active
ingredient and being deposited on a carrier, if desired,
which process comprises: contacting the gas mixture
containing hydrogen and carbon monoxide in a molar ratio
of 0.5-3 : 1 at temperatures of about 200 to 500C and,
optionally~ under pressures of 1 to 100 atmospheres
absolute, with a catalyst, the gas mixture being used
at a rate of about 100 to 10 000 normal liter (S.T.P.)

1073436
per liter of catalyst per hour, and separating hydro-
carbons having from l to 4 carbon atoms from the
issuing gas, said catalyst having been made by
contacting one or more complex salts of the following
general formula: -
Nex ~Fe(CN)~ y
in which Ne stands for an iron and/or copper-ion, x
stands for a number of 1 to 4, and y stands for a
number of 1 to 3, with hydrogen or a hydrogen/carbon
monoxide mixture at temperatures of about 200 to 500C, ~ -
under pressures of 1 to lO0 atmospheres absolute and
over a period of about 2 to 20 hours and thereby
reducing the complex salts to elementary iron or ;
copper.
A preferred feature of the present process provides --
for the gas mixture to contain hydrogen and carbon
monoxide in a molar ratio of 0.8-3:1 and to be
contacted at 250 to 450C under pressures of 5 to 50
atmospheres gauge with the catalyst at a rate of 200
to 5000 normal liter per liter of catalyst per hour.
The following statements are intended further to
illustrate the catalyst and process of the present
invention.
The catalyst can be prepared, for example, by
precipitating copper ferrocyanide from an aqueous
copper-II-salt-solution by means of an aqueous solution
of potassium ferrocyanide. The resulting red-brown
precipitate is suction-filtered, washed and dried.
Next, the precipitate is reduced in a copper-lined
- 6 -
~ -, . . , . , , . . ~ . . . .

10'73436
steel tube at 350-400C over a period of about 2 hours
with the use of hydrogen.
Another method of preparing a very good
hydrogenation catalyst comprises producing an almost
white precipitate from an ammoniacal solution of
copper-I-chloride and potassium ferrocyanide (molar
ratio = 4:1), drying the precipitate and reducing it
by means of hydrogen.
A still further method of preparing an effective
hydrogenation catalyst comprises reacting an aqueous
solution of a copper-II-salt and iron-II-salt with
potassium ferrocyanide in a molar ratio of 1~
separating the result$ng black-blue precipitate, drying
the precipitate and reducing it with hydrogen. The
black-blue precipitate contains iron and copper in an -~
atomic ratio of 1:2. If the atomic ratio of Cu:Fe is ;~ -
further reduced, the catalyst becomes less selective
relative to the formation of C2-hydrocarbons. Even
those catalysts, which are prepared from ferricyanide
and ferrocyanide, have however been found to possess -~
good hydrogenating properties.
The catalysts prepared in the manner described
hereinabove can, for example, be applied to a carrier
by precipitating the complex cyanides in an aqueous
suspension of the carrier, separating the resulting
mixture of precipitated cyanide and carrier, drying
the mixture, washing it and reducing the cyanides by
means of hydrogen at the necessary temperature.
Another method of applying the catalyst to the
carrier comprises impregnating preformed carrier
- 7 -

1073436
material with the complex cyanides by first impregnating
the carrier with an aqueous solution of potassium
ferrocyanide~ then drying the carrier so impregnated
and reacting the carrier with an aqueous solution of a
copper salt.
A still further method comprises mixing the
aqueous solution of potassium ferrocyanide with a
copper salt in the presence of ammonia (precipitation
is obviated~ e.g. in those cases in which a copper~
salt and potassium ferrocyanide are used), impregnating
the carrier with the resulting solution and -
precipitating the copper-cyanide complex by evaporation ~ -
of the ammonia.
It is not absolutely necessary for the dry
catalyst to be treated with hydrogen. It may well be
contacted immediately with the C0/H2-mixture at the
necessary reaction temperature to effect reduction of
the cyanide complex. A catalyst so prepared was taken
after about 8 hours of operation from a reactor and
found to be pyrophorous in contact with air. The
nitrogen content of the catalyst was found to have
dropped to about 0.2 - 0.4 weight Z, i.e. the complex
cyanide compound was found to have been extensively
destroyed.
As more fully illustrated in the following
Examples, the present iron/copper catalysts compare
favorably with the prior art catalyst in respect of the
following points: They can be prepared under commercially
attractive conditions and combine this with a relatively
high selectivity in the reaction of carbon monoxide
- 8 -

1073436
with hydrogen with the resultant formation of Cl-C4
hydrocarbons.
EXAMPLE 1:
Particulate pumice (particle size = 2-3 mm) was
introduced into an aqueous solution of potassium ferro- -
cyanide saturated while hot, supernatant liquid was
poured off, the remaining material was dried and mixed ~-
with a FeC13-solution in excess. The resulting blue
mass was water-washed and dried in a drying cabinet at !
120C. 30 g of the product so obtained was placed in a
copper-lined tube 16 mm wide and reduced by means of
hydrogen over a period of 3 hours at 250-300C under a
pressure of 5 atmospheres gauge.
The catalyst so made was contacted with 30 normal
liter/hr of a H2/C0-mixture (molar ratio = 1:1) under
a pressure of 10 atmospheres gauge. The reaction
temperature was 385C. The gas issuing from the reactor
contained 1.8 Z by volume of ethylene and ethane, 7.2 Z
by volume of methane, 1 Z by volume of C3 hydrocarbons
and 0.8 Z by volume of C4 hydrocarbons. Liquid
hydrocaroons could not be found to have been formed.
The hydrogenation was accompanied by the formation of
co2.
The experiment was repeated under the reduction
conditions described~ but the molar ratio of H2:C0 =
1:1 was changed to 3:1. The quantity of C2, C3 and
C4 hydrocarbons remained unchanged, but 9.3 Z by
volume of CH4 was obtained. Less C02 was found to have
been formed in favor of water.
_ 9 _

" - ~073436 ~ ~
EXAMPLE 2:
The procedure was as described in Example 1, but
granular pumice was charged with K4/ Fe(CN)6 7 and the
granular material was introduced into an aqueous
solution of copper and iron sulfates (molar ratio =
1:1). The cyanide complex applied to the granular pumice
corresponded approximately to the following formula
CuFe / Fe(CN)6 7. The dry granular material was -
contacted with 30 normal liter/hr of a H2/CO-mixture
(molar ratio = 1:1) at 345C under a pressure of 9.5
atmospheres gauge. The gas issuing from the reactor
contained 2.4 % by volume of C2 hydrocarbons, 1.3 % by
volume of C3 hydrocarbons, 1.1 % by volume of C4
hydrocarbons and 6.4 ~ by volume of methane.
EXAMPLE 3.
0.5 mol of K4/ Fe(CN)6 7 was dissolved in a
.
suspension of 90 g of most finely divided silicic acid
- ~ (AEROSIL, a product of Degussa, Frankfurt/Main) in 2
liter of water. Next, a solution of 0.5 mol of CuS04
and 0.5 mol of FeS04 was stirred thereinto. The
resulting precipitate was filtered off together with
silicic acid, thoroughly washed with water and dried.
30 g of the product so obtained was contacted at 340C
and under a pressure of 9.5 atmospheres gauge with 30
normal liter/hr of a H2/CO-mixture (molar ratio = 1:1).
The issuing gas contained 4.4 % by volume of C2
hydrocarbons, 2.2 % by volume of C3 hydrocarbons, 1.2 %
by volume of C4 hydrocarbons and 13.2 % by volume of
methane. Liquid higher hydrocarbons could not be found
to have been formed. The reaction was accompanied by
*Trademark 10
.
D
.

1073436
the formation of C02.
EXAMPLE 4-
The procedure was as described in Example 3, but
the water-washed mixture was mixed with agitation with
5 weight %, based on the dry mixture, of potassium
waterglass, which was a 28 weight ~ aqueous solution,
the whole was dried and comminuted. The dry product
~ was contacted at 360C with a H2/CO-gas mixture to
effect reduction of the cyanide complex to the
catalytically active material. The resulting reaction
gas contained 3.5 % by volume of C2 hydrocarbons
together with 9.6 % by volume of CH4.
EXAMPLE 5:
The procedure was as described in Example 3, but
the AEROSIL silicic acid was replaced by hydrate of
alumina (a commercially available product of Condea
- Petrochemie Gesellschaft mbH, Brunsbuttel). The
reaction temperature was 315C. The reaction gas
contained 2.8 % by volume of C2 hydrocarbons together
with 7.8 % by volume of methane.
EXAMPLE 6:
An aqueous solution of 2 mol of CuS04 was mixed
, with agitation with an aqueous solution of 1 mol of
K4/ Fe(CN)6 7 and copper ferrocyanide corresponding
- approximately to the formula Cu2/ Fe(CN)6 7 was found
to have been precipitated. The precipitate was filtered
off, washed with water, dried and tabletted. 30 g of
the tabletted material was contacted at 360C and
under a pressure of 9.5 atmospheres gauge with 30
normal liter/hr of a H2/CO-mixture. The resulting
_ 11 - '

1073436
reaction gas contained 2.66 ~ by volume of C2
hydrocarbons and 11.7 % by volume of methane. The
hydrogenation was accompanied by the formation of
water.
EXAMPLE 7:
An aqueous copper sulfate solution was introduced
into an aqueous solution of potassium ferrocyanide,
which had fine particulate pumice suspended therein,
to cause precipitation-of copper ferrocyanide which
was deposited on the pumice. The mixture of pumice
and copper ferrocyanide was filtered off, washed with
water and dried at about 60C, 30 g of the product so
obtained was contacted at 320C under a pressure of
9.5 atmospheres gauge with 30 normal liter/hr of a
H2/CO-mixture (molar ratio = 3:1). The resulting
reaction gas contained 3 % by volume of C2
hydrocarbons and 10.5 % by volume of methane. The
oxygen contained in the CO-gas which underwent
reaction was converted to C02.
EX~PLE 8: -
90 g of AEROSIL was suspended in a solution of
0.5 mol of K4/ Fe(CN)6 7 in 2 liter of water. The
suspension was admi~ed with agitation with a solution
of 1 mol of CuS04 and 2 liter of water and
Cu2/ Fe(CN)6 7 was precipitated. The suspension was
filtered, the filter residue was washed with water
and dried. The dry product was contacted at 320C
under a pressure of 9.5 atmospheres gauge with 30
normal liter/h of a CO/H2-gas mixture (molar ratio of
H2:CO = 1:1). After reduction of the dry product to
_ 12 -

"` 1073436
catalytically active material, the catalyst produced
a reaction gas which contained 2.7 % by volume of C2
hydrocarbons, 1.5 % by volume of C3 hydrocarbons, 0.7 %
by volume of C4 hydrocarbons and 4.6 % by volume of
CH4.
EXAMPLE 9
Thepprocedure was as described in Example 8 but
Al203 ~as substituted for the AEROSIL carrier. ~The
Al203 used was a product of Degussa, Frankfurt/Main,
commercially available under the designation
"Aluminiumoxid C"). The resulting reaction gas contained
3.5 % by volume of C2 hydrocarbons and 11.5 % by
volume of CH4.
EXAMPLE iO~
0.5 mol of Cu(N03)2 was dissolved in water,
- admixed with ammonia and the resulting deep blue
solution was decolorized by means of hydroxyl amine
hydrochloride. Next, the solution was admixed with
0.125 mol of K4/ Fe(CN)6 7 in 200 ml of water. The
resulting white precipitate of the approximate formula
Cu4/ Fe(CN)6_7 was filtered off, washed with water,
dried and tabletted. 30 g of the tabletted product
was contacted at 340C under a pressure of ~.5
àtmospheres gauge with 30 normal l/hr of a H2/C0-
mixture (molar ratio = 1:1). The resulting reaction
- - gas contained 2.5 yO by volume of C2 hydrocarbons and
10 % by volume of CH4.
EX~MPLE 11.
~.2 mol of Cu(N03)2 was dissol~ed in water,
admixed with ammonia and the resulting deep blue
*Trademark - 13 - .-
~' . .

1073436
solu-tion was deco]orized by means of hydroxyl amine
sulfate. 90 g of AEROSIL was suspended in the solution
and the resulting suspension was admixed with 0.3 mol
of K4/ Fe(CN)6 7. The suspension was filtered, the
filter residue was washed wi-th water and dried. 30 g
of the dry product was contacted at 325C under a
pressure of 9.5 atmospheres gauge with 30 normal liter/
hr of a H2/CO-gas mixture (molar ratio = 1:1). m e
resulting reaction gas contained 2.6 % by volume of
C2 hydrocarbons and 11.2 % by volume of CH4.
EXAMPLE 12:
The procedure was as described in Example 11, but
the AEROSIL was replaced by alumina (a product of
Degussa, commercially availa~le under the designation
of "Aluminiumoxid C'i). The resulting reaction gas
contained 2.5 % by volume of C2 hydrocarbons and 9.2 %
by volume of CH4.
EXAMPLE 13: (Comparative Example)
A hot solution of 1 mol of Cu(N03)2, 0,5 mol of
Fe(N03)3, 6 g of Zr(N03)4 in 2 llter of water ~ras
admixed with thorough agitation with 2.5 liter of an
aqueous solution containing 2 mol of Na2C03. Next, the
mixture was stirred into 100 g of kieselguhr. The
resulting precipitate was suction-filtered,
thoroughly washed with water and dried. 30 g of the
dry product was reduced by means of hydrogen over a
- period of 2 hours, at 300C and under a pressure of 5
atmospheres gauge. The catalyst so obtained was
contacted with 30 liter/hr of a H2/CO-mixture (molar
ratio = 2:1). The resulting reaction gas contained
- 14- _

1073436
the following quantities of C2 hydrocarbons, methane
and C02, depending on the reaction temperature used
in each particular case.
T a b l e :
Temp. Pressure C -hydrocarbons CH4 C02 '
C ~ atm.gauge 2% by volume ~ by vol. % by vol.
3~0 9.5 0.22 0.98 0.93
390 9.5 O.35 1.60 1.64
410 9.5 0.33 1.65 1.55
The water of hydration present in the salts
specified in the above Examples and used for making
the catalysts has not been identified for reasons of
simplicity.
- 15 -
.
,