Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
5~37
1. MD 29779
This invention relates to the manufacture of mono-
halogenated olefinic compounds by the oxyhalogenation
o~ the corresponding olefines. The invention is also
concerned with a catalyst composition useful in such
a process.
Processes for the manufacture of monohalogenated
olefines by the oxyhalogenation of the corresponding
olefine have been beset with difficulties. This is
particularly true with the oxychlorination of mono-
olefines especially of ethy.lene. There is everyincentive to provide an efficient process for the
oxychlorination of ethylene in a single stage to
give vinyl chloride as the major product. Indeed
very many attempts have been made with much
expenditure of time and money to provide such
a process. Such attempts in the main have been
directed at providing an effective catalyst for
the oxychlQrination process. Many combinations o
catalysts and co-catalyst have been proposed. For
example catalysts have been proposed comprising a
compound of palladium and copper. However processes
based on the use of known catalysts do have severe
disadvanta~es. Thus in the oxychlorination of
ethylene the disadvantages include poor convPrsions
5~7
2. MD 29779
based on starting material, especially based on a
chlorinating agent, poor selectivities to the desired
vinyl chloride product, production o~ considerable
amounts of undesired by-products or considerable
S burning of ethylene to give carbon oxides.
It is an object of the present invention to provide
a novel, much improved oxyhalogenation process wherein
said disadvantages are very much reduced and as such
the process proYides a most valuable contribution to
the art.
According to one aspect of the invention we provide
a process for the oxyhalogenation of a feedstock
comprising an olefine to gi~e a monohalogenated olefine
which comprises bringing into reaction at elevated
temperature in the gas phase an olefine with a source
of halogen and molecular oxygen in the presence of
a supported catalyst composition comprising a compound
of palladium, a compound of copper, a compound of iron
and a compound of an alkali metal.
It is preferred to include in the catalyst
composition a compound of a rare earth metal.
Compounds of different rare earth metals may be
employed. One suitable compound of a rare earth metal
contains a significant amount of a compound of cerium.
As illustrative of the compounds of the alkali metals
compounds of sodium and lithium may be mentioned. A
compound of sodium is preferred.
The compounds of the metals incorporated in the
catalyst composition are suitably but not necessarily
the halides corresponding to the halogen of the mono-
halogenated compound which is produced. In an oxy-
chlorination process, for example of ethylene the
compounds of the metals are suitably the chlorides.
3. MD 29779
In use in the oxychlorination process the composition
may exist as a mi~ture of chlorides, oxychlorides,
oxides and hydroxides. Compounds of metals such as
nitrates, oxides, carbonates, oxalates and acetates
may also be employed which are converted to the
chlorides or said mixtures containing chlorides
under the oxychlorination conditions.
Each component of the present catalyst composition
has an intricate relationship with one or more of
the components of the catalyst composition. ~hile
theories can be propounded by way of explaining the
relationship the practical result is that unless all
of the components are present the improved results
of the present process will not be achieved. When
the rare earth compound is incorporated in the
catalyst composition said compound also shares a
relationship with one or more of the other
components of the composition and in turn contributes
a beneficial result in the efficiency of the process.
~0 We find according to a further and most valuable
feature of the invention that there is an intricate
relationship between the atomic ratios of the various
metals in the present catalyst composition. When
using these atomic ratios and particularly when
~5 using the preferred atomic ratios the advantages of
the present process become more apparent. These
advantages include high conversions of the
chlorinating agent, high selectivities, comparitively
low formation rates of undesired products e.g~ dichloro-
ethylene and 1,1,2-trichloroethane and comparitively
low burning of ethylene. Such advantages have not
been obtained in prior processes.
4. MD 29779
It is preferred to employ an atomic ratio of
palladium to copper in the range 1 atom of palladium
to 0.25 to 10 atoms of copper. Typical catalysts
contain 1 atom of palladium per 1 to 3 atoms of
copper and in particular 1.7 to 2.8 atoms of copper.
The atomic ratio of iron to palladium is suitably
in the range 1:1 to 20:1. Preferably this atomic
ratio is in the range 4 to 10 atoms of iron per atom
of palladium.
The atomic ratio of rare earth metal to palladium
is suitably in the range 1.1 to 15.1. Preferably this
atomic ratio is in the range 3:1 to 8:1.
The atomic ratio of alkali metal to palladium is
suitably in the range 10:1 to 30:1. Preferably this
atomic ratio is in the range 15:1 to 25:1.
The proportion by weight of palladium based on the
supported catalyst is preferably in the range 0.05%
to 0.5%.
The catalyst may be supported on known carriers
such as for example silica and alumina. The surface
area of the support can be varied widely but is usually
in the range 0.1 to 2C m2/g.
The supported catalyst may be employed in fixed,
moving or fluidised beds and of appropriate
particle size.
The feed stock employed in the present invention
is essentially olefinic~ Olefine reactants which can
be employed include for example, ethylene, propylene,
straight and branched-chain olefines containing four
or more carbon atoms and cyclic o'efine such as
cyclohexene.
S~7
5. MD 29779
A particularly suitable olefine for use in the
present invention is ethylene. The olefine may also
contain a saturated hydrocarbon component, for example,
commercially available feedstocks consisting
S essentially of ethylene but also containing a small
proportion of ethane.
The reaction temperatures employed are dependent
to a considerable extent on the reactant employed.
With ethylene suitable reaction temperatures are in
the range ~50~C to 400C, preferably 300C to 370C.
The source of chlorinating agent in the present
process may be chlorine, hydrogen chloride or
substances such as ammonium chloride which on heating
decompose to give hydrogen chloride. More suitably
the source of the chlorinating agent is hydrogen
chloride.
The source of oxygen may be oxygen itself, air
or oxygen enriched air. When using oxygen itself the
oryanic product, by-products and water are removed
and the residual exit gases after suitable monitoring
and analysing can be returned to the system.
The molar ratios of ethylene, oxygen and
hydrogen chloride are preferably such as to provide
0.5 to 1 mole of oxygen and 009 to 1.5 moles
hydrogen chloride for each mole of ethylene. Most
suitably the relative proportion of ethylene: hydrogen
chloride is approximately 1:1.
In the present process the desired products can be
recovered by conventional means. Any dichloroethanes
in the crude organic product can be recycled thereby
giving more of a desired vinyl chloride product.
The present invention also includes a supported
oxychlorination catalyst composition as hereinbefore
described.
The following Examples illustrate the invention.
6. MD 29779
EXAMPLE 1
The support for the catalyst was an alpha-alumina of
surface area 0.6 m2/g and of particle size in the
range 50 to 100 ~m. To a weak solution of
hydrochloric acid were added 0.5g Pd C12, 0.48g
Cu C122H20, 3.65g Fe C13, 6.3g Ce C13.7H20
and 3.95g NaCl. 120g of the support were added to the
solution containing the metal chlorides. The mixture
was stirred continuously at 100C to 150C for a
period of 1/2 hour to 1 hour by which time the
catalyst (Catalyst A) was dry.
Other catalysts were prepared in a similar manner
and are disclosed in Table I.
TABLE I
Atomic Ratios of Metals
Catalyst Pd Cu Fe Ce Na
A 1 ] 8 6 24
B 1 2 5 6 19
C 1 ~l 3 5 16
D 1 2 4 5 17
E 1 7. 5 8 21
F 1 2 16 0 24
EXAMPLE 2
The apparatus comprised a vertical, heat-resistant
glass tube 30cm long and 2.5cm diameter surmounted by
an electric furnace. The tube contained 95g of the
catalyst(s). Ethylene, hydrogen chloride and air
were passed separately into the tube and maintained
the catalyst in fluidised bed conditions and product
was recovered and analysed by conventional means.
7~ MD 29779
The ratio (air calculated as oxygen) of C2H4:HCl:02
was 1:1:0.87.
The temperature conditions and results were as shown
in Table II.
TABLE II
TempC Catalyst % conversion Selectivity % v/v Burnin~
of HCl to specific
products
VC l,l-di EDC C02
364 A 91.5 47.8 9.6 32.2 8.7
362 B 91.6 57.5 4.6 29.0 7.1
365 C 90.6 40.9 8.5 36.5 1~
365 D 86~4 44.0 7.5 36.7 12.2
361 E 83.2 56.9 9.0 ~2.0 12.1
362 F 84.2 51.7 9.0 27.1 12.2
CONVERSION
By way of comparison three catalyst G, H and I were
prepared in the broad manner described in Example 1
but which did not contain all the necessary components
of the catalysts according to the invention. They
were as disclosed in Table III.
TABLE III
Atomic Ratios of Metals
25 Catalyst Pd Cu Fe Ce Na
G 1 0 16 0 24
H 1 2 0 5 17
I 1 0 10 6 24
5~-~
8. MD 29779
Runs were carried as described in Example 2
and the results are shown in Table IV.
TABLE IV
Temp Catalyst % conversion Selectivity ~ v/v Burning
S of HCl to specific
products
VC l,l-di EDC C02
362C G 34.6 54.11.76 14.7 29.5
367C H 78.9 34.212.5 38.2 14.6
361C I 44.7 60.53.6 11.9 23.7
In the above Examples,
VC means Vinyl Chloride
l,l-di means l,l-dichloroethane
EDC means 1,2-dichloroethane
