Note: Descriptions are shown in the official language in which they were submitted.
Le A 30 635-US/ Gai/ngb/S-P 2 1 6 2 6 ~ 3
Process for the oxidation of hydro~en chloride
The present invention relates to an improved process for the preparation of
chlorine from hydrogen chloride.
In the industrial use of chlorine for the preparation of organic compounds, large
amounts of hydrogen chloride form. Thus, for example, in the production of
isocyanates which serve as raw materials for plastic foams and paints, between
0 58 and 1.4 t of hydrogen chloride form per ton of isocyanate. In the chlorination
10 of hydrocarbons, e.g. of benzene and toluene, large amounts of hydrogen chloride
likewise form. Thus in the preparation of chlorobenzene, 0.32 t of hydrogen
chloride forms per ton of chlorobenzene.
Various processes are known for disposing of hydrogen chloride. Thus, for
example, the resulting hydrogen chloride can be split electrolytically into chlorine
15 and hydrogen after transfer to aqueous hydrochloric acid. This process has the
disadvantage of the high requirement for electrical energy. About 1600 KWh are
required per ton of hydrogen chloride to be electrolysed. A further disadvantage is
the high capital costs of providing the electrical energy, of transforming and
rectifying the electric current and especially of the electrolysis cells.
20 For this reason, attempts have already been made to carry out the oxidation of
hydrogen chloride chemically using oxygen and in the presence of catalysts. Thisprocess is termed the "Deacon process" in textbooks of inorganic chemistry (see,e.g., Lehrbuch der anorganischen Chemie, [Textbook of inorganic chemistry],
Hollemann-Wiberg, 40th-46th edition 1958, pp.81 and 455). The advantage of this
25 Deacon process is that no energy needs to be supplied from outside for the
reaction. However, a disadvantage in this process is that the reaction can only be
carried out to an equilibrium position. Therefore, after the Deacon process has
been carried out, a mixture must always be separated which still contains
hydrogen chloride and oxygen.
30 Attempts have already also been made to remedy this fundamental disadvantage of
the Deacon process by a procedure in two stages. The use, e.g. of catalyst
systems, is described, for example Cu(I) salts (see US-A 4 119 705, 2 418 931,
2 418 930 and 2 447 323) or vanadium oxides (see US-A-4 107 280) which are
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able to absorb oxygen and hydrogen chloride and, under other experimental
conditions, e.g. at relatively high temperature, to eliminate chlorine again with
reformation of the original catalyst. The advantage of such a concept is that the
reaction water formed in the reaction of hydrogen chloride with the oxygen-
containing catalyst can be separated off in the 1 st stage and highly enriched
chlorine is formed in the 2nd stage. A disadvantage in this concept is that the
catalyst system must be heated and cooled between the two reaction stages and, if
appropriate, must be transported from one reaction zone to the other. In
combination with the relatively low ability of the catalysts used to release oxygen
- e.g. 1 t of vanadium oxide melt can release only about 10 kg of oxygen - this
means considerable technical complexity which consumes a large part of the
advantages of the Deacon process.
The concepts existing to date for the industrial implementation of the Deacon
process in a single-stage reaction are unsatisfactory. The proposal made by Deacon
in the 19th century, to use a fixed-bed reactor having a copper-containing catalyst
using air as oxidizing agent, delivers only highly dilute, impure chlorine, which at
any rate can be used for the preparation of chlorine bleaching liquor (see Chem.Eng. Progr. 44, 657 (1948)).
An improved technique was developed with the so-called "Oppauer-process" (see
DE 857 633), in which, for example, a mixture of iron(III) chloride and potassium
chloride is used which, as a melt at temperatures of approximately 450C, servesas reaction medium and catalyst. The reactor used is a tower, lined with ceramicmaterial, having a centrally built-in inner pipe, so that passing in the feedstock
gases, hydrogen chloride and oxygen, effects a circulation of the molten salts.
However, an exceptional disadvantage in this concept is the very low space-time
yield (about 15 g of chlorine per litre of melt and per hour). For this reason, the
Oppauer process is not advantageous in comparison with electrolysis of hydrogen
chloride.
The poor space-time yield is accompanied by a large number of further
disadvantages, such as large standing volumes of molten salts, large apparatus
volumes with correspondingly high capital costs and cost-intensive maintenance.
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Furthermore, thermal management of such large melt volumes can only be
performed very poorly with respect to temperature maintenance, heating up and
during shutdown of the plant, which is further reinforced by the thermal inertia of
the large reactors.
S In order to avoid these disadvantages, it has been proposed to carry out the
reaction at a lower temperature, e.g. below 400C. However, at these temperatures
there is the possibility of solids separating out from the copper salt melt. The salt
melt has therefore been applied to a particulate inert support, e.g. silica or
aluminium oxide, and the reaction has been carried out in a fluidized bed (see GB-
B 908 022). A new proposal recommends chromium-cont~ining catalysts on inert
supports, a temperature below 400C likewise being chosen (see EP-A 184 413).
In all of these proposals for solving the problems of the Deacon process using the
fluidized-bed technique, the unsatisfactory stability of the catalysts and their highly
complex disposal after deactivation is highly disadvantageous. In addition, the fine
15 dust which is unavoidable in the fluidized-bed technique poses problems in its
removal from the reaction mixtures. Moreover, the fluidized reaction zone which
requires a hard catalyst leads to increased erosion which, in combination with the
corrosion caused by the reaction mixture, produces considerable technical
problems and impairs the availability of an industrial plant.
20 A further disadvantage of the procedure using molten salts on inert supports, i.e. at
temperatures of above 400C, is that a satisfactory reaction rate and, consequently,
a good space-time yield is only possible if a relatively high oxygen excess is
employed. However, this requires work-up of the reaction mixture using a solvent,
e.g. CC14 or S2Cl2 (see DE-A 1 467 142).
25 The obj ect was therefore to find a process which permits the oxidation of
hydrogen chloride with oxygen in the simplest manner possible and with a high
space-time yield and which uses the technique which is advantageous per se of
employing a system of molten salts as catalyst as opposed to the fluidized-bed
technique for the Deacon process and avoids the disadvantages of the previous
30 variants, e g,. the two-stage salt melt process or the single-stage Oppauer process.
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It would, moreover, be advantageous in this context if a smaller oxygen excess in
comparison with stoichiometric conditions could be employed.
A process has now been found for the oxidation of hydrogen chloride by oxygen
in the presence of a salt melt, which is characterized in that the salt melt contains
5 promoters.
Salt melts without promoters can be, e.g., mixtures of metal salts and salts
depressing the melting point. Metal salts can be both catalytically inactive andcatalytically active salts for the oxidation of hydrogen chloride by oxygen. In each
case, the addition according to the invention of a promoter effects an increase in
10 the reaction rate and the space-time yield.
Metal salts which can be used are, e.g., salts of metals of main groups I to V and
subgroups I to VIII of the Periodic Table of Elements. Preference is given to salts
of aluminium, lanthanum, titanium, zirconium, vanadium, niobium, chromium,
molybdenum, tungsten, manganese, iron, cobalt, nickel, copper and zinc. Particular
15 preference is given to salts of vanadium, chromium, manganese, iron, cobalt,
nickel, copper and zinc. Very particular preference is given to copper salts.
Salts depressin~, the melting point can be, e.g., salts of metals of main groups and
subgroups I to III and main groups IV to V of the Periodic Table of the Elements,
for example salts of lithium, sodium, potassium, rubidium, caesium, magnesium,
20 calcium, strontium, barium, aluminium, gallium, indium, thallium, germanium, tin,
antimony, bismuth, lead, zinc and silver. Preference is given to salts of lithium,
sodium, potassium, aluminium and zinc. Particular preference is given to salts of
potassium
Salt melts without promoters are, e.g., mixtures of the following type:
25 LiCI/KCI, ZnCI2/KCI, KCI/NaCI/LiCI, MgCI2/KCI, AICI3/KCI, AlCI3/NaCl,
V20s/K2SO4/K2S207, CrCI3/NaCI/KCI, MnCI2/NaCI, MnCI2/KCI,
MnCI2/KCI/NaCI, MnCI2/AlCI3, MnCI2/GaCI3, MnCI2/SnCI2, MnCI2/PbCI2,
MnCI2/ZnCI2, FeCI3/LiCI, FeCI3/NaCI, FeCl3/KCI, FeCI3/CsCI, FeCI3/KCI,
FeCI3/AlCI3, FeCI3/GaCI3, FeCI3/SnCI4, FeCI3/PbCI2, FeCI3/BiCI3, FeCI3/TiCI4,
FeCI3/MoCls, FeCI3/ZnCI2, FeCl3/NaCI/ZrCI4, FeCI3/KCI/ZrCl4,
Le A 30 635-US 2 16 2 6 9 3
FeC13/NaCl/WC 14, CoC12/NaCI, CoC12/KCI, CoC12/GaC13, CoC12/SllCl2,
CoCl2/PbCl2, CoCI2/ZnCl2, CuCl/NaCI, CuCI/KCI, CuCI/RbCI, CuCI/CsCl,
CuCI/AlC13, CuCI/GaCI3, CuCl/InCl3, CuCl/TlCI, CuCl/SnCl2, CuCI/PbCl2,
CuCl/BiCI3, CuCl/FeCl3, CuCl/AgCI, CuCl/ZnCl2, LaCl3/FeCl2/SnCI2,
NaCI/SnCI2, FeCI2/SnCI2 and NaCI/CaCl2. Preference is given to mixtures of the
type V2O5/K2SO4/K2S2O7, CrCl3/NaCl/KCl, MnCI2/KCl, FeCl3/KCI and
CuCI/KCI. Particular preference is given to mixtures of the type
V2Os/K2SO4/K2S2O7, FeCl3/KCI and CuCl/KCl. Very particular preference is
given to a mixture of KCl and CuCl.
If metal oxides, e.g. V2O5, are used, these convert into salts when the process
according to the invention is carried out.
The promoters to be added according to the invention to the salt melts can be,
e.g., metal salts of subgroups I to VIII of the Periodic Table of the Elements
and/or of the rare earths, for instance salts of scandium, yttrium, lanthanum,
lS titanium, zirconium, hafnium, vanadium, niobium, tantalum, chromium,
molybdenum, tungsten, manganese, rhenium, iron, ruthenium, cobalt, rhodium,
iridium, nickel, palladium, platinum, copper, silver, gold and salts of the rareearths, for instance salts of, for example, cerium, praseodymium, neodymium,
samarium, europium, gadolinium, and of thorium and uranium. Preference is given
to salts of lanthanum, titanium, zirconium, vanadium, chromium, molybdenum,
tungsten, manganese, rhenium, iron, ruthenium, cobalt, rhodium, iridium, nickel,palladium, platinum, copper, cerium, praseodymium, neodymium and thorium.
Particular preference is given to salts of lanthanum, vanadium, chromium,
manganese, iron, cobalt, nickel, copper, cerium, praseodymium and neodymium.
Very particular preference is given to salts of iron and copper.
Mixtures containing promoters to be used according to the invention are, e.g
mixtures of the following type:
LiCI/KCI/FeCI3, LiCI/KCI/NdCl3/PrCl3, KCl/NaCl/LiCl/FeCI3
KCI/NaCI/LiCI/NdCl3/PrCl3, MgCl2/KCl/FeCl3, MgCl2/KCI/NdCl3/PrCl
MgCI2/KCI/LaCI3, MgCI2/KCI/CeCI3, AlCI3/KCI/FeCI3, AlCI3/KCI/NdCI
AlCI3/KCI/PrCI3, AlCI3/KCl/NdCI3/PrCI3, AlCI3/KCI/LaCl3, AlCl3/KCI/CeCI
AlCI3/NaCI/FeCI3, AlCl3/NaCllNdCI3, AlCI3/NaCI/PrCI3, AlCI3/NaCI/NdCl3/PrCl
LeA30635-US 216264~
AlCI3/NaCI/LaC13, AlCI3/NaCl/cecl3, V25/K2S4/K2S27/FeC13
V~s/K~S4/K2S27/CUCI, V2o5lK2so4lK2s2o7lL
V205/K2SO4/K2S207/CeCl3, V2o5lK2so4lK2s2o7lNdcl3
V205/K2SO4/K2S207/NdCI3/PrCI3, CrCI3/NaCI/KCI/FeCI3, MnCI2/KCI/FeCI3,
MnCI2/KCI/LaCI3, MnCI2/KCI/CeCI3, MnCI2/KCI/NdCI3/PrCI3,
MnCI2/AlCI3/FeCI3, MnCI2/KCI/NaCI/FeCI3, MnCI2/SnCI2/FeCI3,
MnCI2/SnCI2/LaCI3, MnCI2/SnCI2/CeCI3, MnCI2/SnCI2/NdCI3, MnCI2/SnCI2/PrCI3,
MnCI2/SnCI2/NdCI3/PrCI3, FeCI3/KCI/NdCl3/PrCl3, FeCI3/LiCI/CuCI,
FeCI3/NaCI/CuCI, FeCI3/KCI/CuCI, FeCI3/ZnCI2/CuCI, FeCI3/NaCI/ZrCI4,
CoCI2/SnCl2/FeCI3, CuCI/KCI/FeCI3, CuCI/AlCI3/FeCI3, CuCI/BiCI3/FeCI3,
CuCI/CsCI/FeCI3, CuCI/FeCI3, CuCI/SnCI2/FeCI3, CuCI/ZnCI2/FeCI3,
CuCI/TlCI/FeCI3, CuCI/KCI/NdCI3, CuCI/KCI/PrCI3, CuCI/KCI/LaCI3,
CuCI/KCI/CeCI3, CuCI/KC 1 /NdCI3/PrCI3, ZnCI2/KCI/FeCI3,
ZnCI2/KCI/NdCI3/PrCl3. Preference is given to mixtures of the type:
V~O5/K2SO4/K2S2O7/FeCI3, FeCI3/KCI/NdCI3/PrCI3, CuCI/KCI/FeCI3,
CuCI/AlCI3/FeCI3, CuCI/BiCI3/FeCI3, CuCI/CsCI/FeCI3, CuCI/FeCI3,
CuCI/SnCI2/FeCI3, CuCI/ZnCI2/FeCI3, CuCI/KCI/NdCI3, CuCI/KCI/PrCI3,
CuCI/KCI/LaCI3, CuCI/KCI/CeCI3, CuCI/KCI/NdCI3/PrCI3, CeCl3/NaCI/SnCI2,
CeCI3/FeCI2/SnCI2 and NdCI3/NaCI/CaCI2. Particular preference is given to
CuCI/KCI/FeCI3, CuCI/KCI/NdCI3, CuCI/KCI/PrCI3 and CuCI/KCI/NdCI3/PrCI3
mixtures. Very particular preference is given to a mixture of CuCI, KCI and
Fecl3.
The salt melts containing promoters and to be used according to the invention can
if appropriate also simultaneously contain a plurality of components from the
group consisting of the metal salts, the salts depressing the melting point and/or
the promoters.
If a promoter also complies with the definition given for the salts depressing the
melting point, in this case the separate addition of a salt depressing melting point
is not absolutely necessary; the promoter then assumes both functions. However, it
is preferable to employ salt melts which contain at least 3 different components, at
least one component complying with the definition given for metal salts, at least
one component complying with the definition given for salts depressing the
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melting point and at least one component complying with the definition given forpromoters.
If the metal component of the salt melt constituents described can assume a
plurality of oxidation states, for example iron, copper or vanadium, this metal
5 component can be used in any oxidation state or in any mixtures of different
oxidation states. While the process according to the invention is being carried out,
the oxidation state can change.
The amount of the salts depressing the melting point employed in the process
according to the invention, based on the entire melt, can be between 0 and 99%
10 by weight, preferably between 10 and 90% by weight and corresponds, very
particularly preferably, roughly to the composition of the eutectic mixture of the
components used.
The promoters need not be completely dissolved in the salt melt during the
reaction, but this is preferred. Their concentration in the salt melt can be, e.g. 0.01
to 100 mol%, preferably 0.1 to 50 mol%, and particularly preferably 0.1 to 10
mol%, in each case based on the entire salt melt.
The metal salts, salts depressing the melting point and promoters to be used
according to the invention can be used, e.g., directly as salts, e.g. as halides,
nitrates, sulphates or pyrosulphates. Precursors of metal salts can also be used, e.g.
metal oxides or metal hydroxides or elemental metals which transform into metal
salts when the process according to the invention is carried out. Preferably,
chlorides are used.
The reaction temperature required to achieve a high yield essentially depends onthe activity of the salt melt containing the promoters used. It is generally between
room temperature and 1000C. Preferably, temperatures between 300C and 600C
are employed, particularly preferably those between 350C and 550C.
The pressure for carrying out the process according to the invention can be, e.g.,
between 0.1 and 50 bar. Preferably, pressures between 0.5 and 10 bar are
employed, particularly preferably those between 1 and 3 bar.
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The oxidation according to the invention of hydrogen chloride succeeds in
principle using any oxygen-containing gases. Preferably, however, gases are
employed which have an oxygen content of more than 90% by volume of oxygen.
The ratio of hydrogen chloride to oxygen can be varied in broad ranges. For
5 example, the molar ratio of hydrogen chloride to oxygen can vary between 40:1
and 1:2.5. Preferably, this ratio is between 20:1 and 1:1.25, particularly preferably
between 8:1 and 1:0.5, very particularly preferably between 5:1 and 1:0.3.
The process according to the invention is advantageously carried out in such a
way that the feedstocks are conducted into a reaction zone as a continuous phase10 and the salt melt containing promoters is dispersed in the continuous phase.
The term feedstocks is to be taken to mean the gas mixture of hydrogen chloride
and oxygen to be brought to reaction, which mixture can possibly contain inert gas
portions, e.g. nitrogen, carbon dioxide, argon and/or helium or impurities, e.g.carbon monoxide.
15 In the reaction zone, with advancing reaction, a continuous conversion of the feedstocks to the products takes place in accordance with the equation
4 HCI + 2 ~ 2 Cl2 + 2 H2O.
The product mixture contains chlorine, steam, possibly inert gas portions and can
contain impurities and unreacted feedstocks. With suitable reaction conditions, by
20 using the process according to the invention the thermodynamic equilibrium can
be set, i.e. the maximum possible chlorine yield can be achieved.
It is advantageous to run the process according to the invention in such a way that
the contact times between the continuous phase and the disperse phase are
between 0.001 and 500 seconds, preferably between 0.01 and 50 seconds,
25 particularly preferably between 0.1 and 4 seconds.
Preferably, the continuous phase of the feedstocks and the salt melt containing
promoters are run in counter-current.
Le A 30 635-US 2162643
Reaction apparatuses which are suitable for carrying out the process according to
the invention industrially are, e.g., trickling film reactors, packed reactors, spray
tower reactors and bubble column reactors.
Preference is given to trickling film reactors. The process according to the
5 invention can be carried out continuously, discontinuously or in cycles.
The process according to the invention permits the oxidation of hydrogen chloride
by oxygen or an oxygen-containing gas in the presence of a salt melt with higherconversion rates than according to the prior art. Furthermore, the reaction succeeds
with higher space-time yields and in a simpler manner than according to the prior
1 0 art.
The process according to the invention further has the advantage that the addition
of promoters increases the reaction rate and by this means conversion rate and
space-time yield are markedly improved. Consequently, smaller reactors can be
used and the capital costs can be decreased. The smaller volume of the salt melt to
15 be handled decreases the energy losses which occur, e.g. during the heat-up
process. In addition, the start-up and shut-down processes are shortened.
The superiority of the process according to the invention with respect to the prior
art is illustrated by the following examples.
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~o
Examples
Example 1
In a 1 I glass reactor which, for relatively small batches, acts as a model for
reactors to be used industrially, a mixture of 318.6 g (4.27 mol) of potassium
S chloride, 423.0 g (4.27 mol) of copper(I) chloride, 158.1 g (0.44 mol) of
neodymium chloride hexahydrate and 68.5 g (0.19 mol) of praseodymium chloride
hexahydrate (molar ratio: 1: 1 :0.1 :0.045) was introduced as initial charge andheated to a temperature of 450C. The mixture melted at about 150C and became
a virtually black, easily stirrable melt which occupied a volume of 415 ml. 48 I/h
of hydrogen chloride and 12.61/h of oxygen (technical grade quality) were
introduced continuously with stirring through a glass frit. After equilibrium was
established, the chlorine yield was determined by introducing the product gas
stream into a potassium iodide solution and iodometric determination with
thiosulphate. The chlorine yield achieved can be seen in Table 1.
Exam ple 2
In a I I glass reactor a mixture of 289.3 g (3.88 mol) of potassium chloride,
768.2 g (7.76 mol) of copper(I) chloride and 21.0g (0.078 mol) of iron(III)
chloride hexahydrate was introduced as initial charge and heated to a temperature
of 450C. This gave a melt having a volume of 415 ml. The procedure was then
followed as in Example 1. The chlorine yield achieved can be seen in Table 1.
Example 3 (for comparison)
In a 1 I glass reactor, a eutectic mixture of 289.3 g (3.88 mol) of potassium
chloride and 768.2 g (7.76 mol) of copper(I) chloride was introduced as initial
charge and heated to a temperature of 450C. This gave a melt having a volume
of 415 ml. The procedure was then followed as in Example 1. The chlorine yield
achieved can be seen in Table 1.
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T~ble I
Example Chlorine yield (% of theory)
472
2 469
3 (comparison) 23 4
Ex~mples 4-8
In a I I glass reactor, a eutectic mixture of 289.3 g (3 88 mol) of potassium
chloride and 768.2 g (7.76 mol) of copper(I) chloride was introduced as initial
charge and heated to a temperature of 450C. This gave a melt having a volume
10 of 415 ml. Neodymium chloride hexahydrate (see Table 2 for the amounts) was
then added and the procedure was followed as in Example 1 The chlorine yields
achieved after equilibrium had been established can be seen from Table 2.
T~ble 2
ExampleNeodymium chlorideReaction temperature Chlorine yield
(mol% with respect to (C)
copper) (% of theory)
4 1 480 45.4
1 420 19.1
6 2 450 41.1
7 4 480 57.1
8 8 450 62.3
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Examples 9-16
In a 1 l glass reactor, a eutectic mixture of 289 3 g (3.88 mol) of potassium
chloride and 768.2 g (7.76 mol) of copper(I) chloride was placed as initial charge
and heated to a temperature of 450C. This gave a melt having a volume of 415
5 ml. Iron chloride trihydrate (see Table 3 for amounts) was then added and the
procedure was followed as in Example 1. The chlorine yields achieved after
equilibrium had been established can be seen in Table 3.
Table 3
Example Iron chloride Reaction temperature Chlorine yield
(mol% with respect (C)
to copper) (% of theory)
9 0.25 450 30 0
0 5 450 32.2
I l 1 420 21.7
12 1 390 14 0
13 2 420 30 0
14 4 450 39 9
16 450 42.5
16 0 480 30 4
for comparison
Example 17
20 In a continuously operated trickling film reactor a gas mixture preheated to 480C,
comprising 326 g of hydrogen chloride and 71 g of oxygen, was reacted per hour
at 480C in the presence of a salt melt, comprising a mixture of 1174 g of
potassium chloride, 1001 g of copper(I) chloride, 2255 g of copper(II) chloride
and 600 g of neodymium chloride hydrate. Per hour, 25 l of melt were transported
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at intervals pneumatically by the feedstock gas stream to a storage vessel situated
above the packed bed, continuously added to a column (d = 50 mm; h = 270 mm)
packed with Raschig rings and brought into contact with the feedstock gases in
counter-current. The product gas mixture leaving the reactor comprised, per hour,
218 g of hydrogen chloride, 47.2 g of oxygen, 104 g of chlorine and 26.5 g of
steam.
Example 18
In a continuously operated trickling film reactor a gas mixture preheated to 480C,
comprising 81.5 g of hydrogen chloride and 17.8 g of oxygen, was reacted per
hour at 480C in the presence of a salt melt comprising a mixture of 1174 g of
potassium chloride, 1001 g of copper(I) chloride, 2255 g of copper(II) chloride
and 600 g of neodymium chloride hydrate. Per hour, 25 1 of melt were transportedat intervals pneumatically by the feedstock gas stream to a storage vessel situated
above the packed bed, continuously added to a column (d = 50 mm; h = 270 mm)
packed with Raschig rings and brought into contact with the feedstock gases in
counter-current. The product gas mixture leaving the reactor comprised, per hour,
27.3 g of hydrogen chloride, 5.9 g of oxygen, 52.6 g of chlorine and 13.3 g of
steam.
Ex~ml)le 19 (for comparison)
In a continuously operated trickling film reactor a gas mixture preheated to 480C,
comprising 407.5 g of hydrogen chloride and 85.2 g of oxygen, was reacted per
hour at 450C in the presence of a salt melt, comprising a mixture of 1174 g of
potassium chloride, 1001 g of copper(I) chloride and 2255 g of copper(II)
chloride. Per hour, 20.6 1 of melt were transported at intervals pneumatically by
the feedstock gas stream to a storage vessel situated above the packed bed,
continuously added to a column (d = 50 mm; h = 270 mm) packed with Raschig
rings and brought into contact with the feedstock gases in counter-current. The
product gas mixture leaving the reactor comprised, per hour, 361.7 g of hydrogenchloride, 75.6 g of oxygen, 44.3 g of chlorine and 11.25 g of steam.
