Note: Descriptions are shown in the official language in which they were submitted.
o~
HOE 81/H 043
It is known that 1,2-dichloroethane can be made by
reacting ethylene with chlorine in 1,2-dichloroethane as
a solvent and reaction medium. The principal by-product ob-
tained in this reaction is 1,1,2-trichloroethane which ori-
ginates from a substitution reaction 1,2-dichloroethane
is subjected to~ In order to obviate this substitution re-
action9 use is made of catalysts which comprise chlorides
of the elements belonging to groups IV to VI of the Peri~-
dic System, and are partially used in the presence of oxy-
gen; more especially, anhydrous iron(III)chloride which isreadily accessible and inexpensive is used.
The resulting crude catalyst-containing dichloroethane
is normally taken from the reaction ~essel, treated with
water or aqueous alkali metal solution so as to be ~reed
from catalyst and hydrogen chloride, and distillati~ely
worked up in known manner.
The use of FeCl3 as a catalyst in the addition chlori-
nation of ethylene entails certain adverse effects. In the
presence of water, for example, FeCl3 has corrosiveness for
metallic mate~ als such as those normally used for making
reactors, columns or heat exchangers provided of course
that these come into contact ~herewith. Needless to say,
chlorine of commercial purity which is normally used for
e~fecting the chlorination always contains traces of water
and hy~rogen chloride origi~ating from undesirable side
reactions,
Whene~er it is desirable for the heat energy set free
during the chlorination of ethylene to be utilized9 it is
~.
y~
invariably necessary for the reaction to be carried out at
temperatures higher than the boiling point of dichloro-
ethane at atmospheric pressure. In ~iew of the fact that
corrosiveness increases considerably with increasing tem-
peratures, it is indispensable to effect the chlorinationreaction in apparatus lined with corrosion-resistant mate-
rials which naturally affect the commercial at-tracti~eness
of the entire process.
We ha~e now ~ound that FeC13 which is used as a cata-
lyst in the production of 1,2-dichloroethane is of consi-
derably reduced corrosi~eness .~or reactor materials which
are not corrosionproof provided that the ~eCl3-catalyst is
used in admixture with certain addends. In addltion to this,
the addends have been found favorably to influence by-pro-
duct formation which is reduced.
The present invention relates more particularly to acatalyst mixture consisting o~ anhydrous iron(III)chloride
and a further mixing component, for making 1,2-dichloro-
ethane by subjecting ethylene to reaction with chlorine in
a solvent at atmospheric or elevated pressure, which is cha-
racterized in that the fur-ther mixing component is a n$tro-
gen base or salt thereof which is used in a proportion appro-
ximately equivalent to the iron(III~chloride proportion.
The nitrogen base is selected ~rom NH3, a primary, se-
condary or tertiary alkyl, aralkyl, aryl or alicyclic amine
or polya~ine; The salt of the nitrogen base preferably is ahalogen salt, e.g. ammonium chloride.
The in~ention also relates to a process for making
1,2-dichloroethane with the use o~ the present catalyst mixture.
5~7
The invention provides a process for makiny 1,2-
dichloroethane by subjecting ethylene to reaction with chlorine
in a solvent at a-tmospheric or elevated pressure in the
presence of a catalyst mixture consistinc~ of anhydrous iron
(III) chloride and a nitrogen base or a salt thereof, which
is used in a proportion approximately equivalent to the
iron(III)chloride proportion.
The process of the present invention for making
1,2-dichloroethane by subjecting ethylene to reaction with
chlorine in a solvent in the presence of a catalyst mixture
consisting of anhydrous iron(III)chloride and a further mixing
component and, if desired, an agent inhibi-ting the formation
of by-products at a temperature of about 20 to 200C, at
atmospheric or elevated pressure and distil.la-tivel~ separating
the 1,2-dichloroet~ane from the chlorination mixture, is
more particularly characterized in that
a) the further mixing component is a nitrogen hase or
a salt thereof;
b) the further mïxing component is used in a propo.rtion
approximately equivalent to the proportion of iron
(III)chloride, and
c~ the iron(III)chloride is used in a concentratio.n of
O.OQ5 to about 0.5 weight ~, based on the quantity
of solvent.
In describing the catalyst mixture, it has already
been mentionsd that the nitrogen base should be selected from
NH3~ a primary, secondary or tertiary alkyl, aralkyl, aryl or
alicyclic amine or polyamine. The salt of the nitrogen base
preferabl-y is a halogen salt, especially ammonium chloride.
~n ~
~ J~
A preferred feature of the present process provides
for 1,2-dichloroethane to be used as the solven-t and for oxygen
to be used as inhibitor.
The following sta-tements are intended further to illus-
trate the process of this invention.
The catalyst should generally be clissolved or suspended
in the solvent placed in a reactor. It is also possible how-
- 3a -
ever for the catalyst to be prepared outside ~he reactor
i.e. by suspending anhydrous FeC13 together with the further
catalyst component in 1,2-dichloroethane, for example, and
for the suspension to be introduced into the reactor St~ll
further, it is possible to introduce a~hydrous FeC17 and NH3
or an amine int~ the solvent placed in the reactor, and ini-
tiate a reaction during which hydrogen chloride sufficient
~or the formation o~ the corresponding ammonium salt is set
free.
The present catalyst can be said to compare fa~orably
with the prior art catalysts inasmuch as it is of conside-
rably reduced corrosiveness for reactors made up of not cor-
rosionproof metals, compared with the corrosiveness in the
prior art methods for making 1,2-dichloroethane. It was also
found that apart ~rom minor proportions of 1,1,2-trichloro-
etha~e (as the first substitution product) and a correspon-
dingly minor proportion of hydrogen chloride, practically
no further by-products are being formed under the process
conditions selected in accordance with this invention. The
reaction solution remains~clear e~en after reaction over a
prolonged period provided that the solution contains the
addends of this invention in proportions approximately equi-
valent to the iron chloride present. It is even possible for
reaction mixture rendered dark during reaction to re-assume
a lighter coloration during the Iurther course of the reac-
tion, upon the addition o~ the addends specified hereinabo~e.
Further desirable results of the present process reside in
the almost quantitative conversion rate at high space/time-
yields.
~39~S'~
The process of this invention can be carried out, for
e~ample, in the loop reactor described in DE-OS 24 27 045
or any other suitable reactor.
The following Examples illustrate the invention.
Example 1
2.0 kg 1,2-dichloroethane and 4 g anhydrous iron(III)
chloride were placed in a loop reactor which had a capacity
of about 2 liters. Next, 0.42 g ammonia which was in the
form of an O.67 weight ~ solution in dichloroethane was in-
troduced at 30 - 40C. The ascending portion of the reactor
loop was provided with a layer of packing material. Disposed
below the layer of packing material so as to open into the
reactor were ethylene, chlorine and air inlets for the in-
troduction of about 60 l/h each of ethylene and chlorine
and 15 l/h air. The reactor liquid was circulated in the
reactor system in accordance with the principle underlying
a mammouth pump and the catalyst mixture was thereby homo-
geneously suspended in the liquid phase. During the reaction,
a temperature of about 77C was found to establish in the
reaction mixture. The concentration of the catalyst mixture,
determined as FeCl3, which was dissolved in the reactor li-
quid, was 0,13 weight % after se~eral days. Dichloroethane
in vapor form which came from the reactor was condensed in a
water cooler arranged above the reactor. 3y means o~ a con-
densate distributing means, a condensate portion correspond-
ing to the quantity produced was ~aken from the cooler whilst
condensate in excess was recycled to the reaction zone. By
means of a cooling trap, a further dichloroethane p~rtio~
was separated from issuing gas which consisted substantially
~ 8 ~
of inert gases. After continuous operation over 2 period
o~ several days, the catalyst mixture was found to have
been extensively dissolved in the reactor liquid; the Fe-
content in the reac~or liquid was determined colorimetrical-
ly and f~und to be about 0.13 weight %. The experiment wasr~n o~er a period o~ 14 days and 1,2-di.chloroethane was ob-
tained at an hourly rate of 262 g.
Product A which was obtained in the condenser and Pro-
duct B which was reactor liquid were analyzed a~ter the re-
action had been terminated, and the following results wereobtained:
Product A Product B
wgt % wgt %
_ _ ~
C2H5 l < 0.002 ~0.002
1,2-EDC 99.94 99.82
1,1,2-ETC ~.04 0.14
HCl ~ 0.001
r~r-~-r ~o-~r~ o o~ 0.04
EDC = 1,2-dichloroethane
ETC = 1,1 7 2-trichloroethane
Ex~mple 2
The procedure was as in Example 1 but the reaction
mixture circulated through the reactor was ad~itionally ad-
mixed dropwise by means of a dropptng funnel with 50 ml/h
1,2-dichl~roe~hane con~aining 0.4 weight % 1,1j2-trichloro-
ethane. 1,2-dichloroethane was obtained at an hourly rate of
~26 g. The experiment was run over a period of 8 days~ Pro-
duct A obtained in the condenser and reactor liquid B~ wereanalyzed after the reaction had been terminated, and the
following results were obtained:
__
Product A Product B
_ wgt % wgt % .
. .. . . . _
C2H5Cl ~ 0.002 ~0.002
1,2-EDC 99.87 99.61
1,1,2-ETC 0.10 0.34
HCl ~ 0.001
Further components O.03 O.05
Example 3
The procedure was as in Example 1 but the concentration
of FeCl3 in the reaction mixture and the molar ratio of FeCl3
to ammoni~ were varied. The followi~g Table indicates the va-
riatio~ and its effect upon the proportions of 1,1,2-ETC and
HCl in the product obtained in the condenser:
. .. . . _ . . , ., , ,,, , . , . _
Concentration Molar ratio Wgt% 1,1,2-ETC Wgt % HCl
FeC1~5 (wgt%)' Fc 13 3
, ;~ .
0.07 1 : 2 0.2 0~004
0.34 1 : 2 0.6 0.002
0.45 1 : 1.5 0.1 0.001
0.32 1 : 1 0.06~ 0.001
In the experiment run with 0.32 wgt % FeC13-concen-
tration over a period of 19 days, 1,2-dichloroethane was
obtained at an hourly rate of 260 g. Product A obtained
in the condenser and reactor liquld B were analyzed a~ter
the reaction had been terminated, and the ~ollowirlg re-
sults were obtained:
Pr~duct A Product B
wgt % wgt %
.. .. . . . .
C2H5Cl ' 0,002 0.002
'I,2-EDC 99.93 99.78
1,1,2-ETC 0.06 __ .0,19
HCl 0.001
Further components O.01 O.03
.. . ... . _...
Example 4
The procedure was as in Example 1 but 1.~5 kg 1,2-di-
chloroethane was used and the reaction solution was admixed
with 1.3 g trimethylamine dissolved in 30 ml 192-dichloro-
ethane, which replaced ammon~a, The experimen~ was run over
a peri~d o~ 6 days and 1,2-dichloroethane ~as obtained at an
hourly rate o~ 276 g. The FeCl3-content in the solution was
determined colorimetrlcally; it averaged 0.13 weight %.
Pr~duct A obtained in the condenser was analyzed after
the reaction had bee~ terminated and the following results
were obtained:
Product A (wgt %)
2 5
1,2-EDC 99.86
1,1,2-ETC 0.13
HCl 0.01
Fbrther ~om~e~t~ O.006
Example 5
The procedure was as in Example 4 but the catalys-t added
to the reaction solution was 1.7 g FeCl3 and 0.65 g diamino-
ethane. The FeCl3-content in the solution was determined colo-
rimetrically; it averaged 0.07 wgt %. The experiment was run
over a period of 3 days a~d dichloroethane was ~btained at
an hourly rate of ~68 g,
Product A obtained in ~he conde~ser was analyzed and the
~ollowing results were obtalned.
9 ~ ~ ~
Product A (~Ygt %j
___ _ ~
C 2H5
1~2-EDC 99,1
1,1,2-ETC 0.85
HCl 0,02
EIr~l~e- ~o~ =0 01
Example 6
The procedure was as in Example 1 but 1.5 kg 1,2-dichlo-
roethane and 3.3 g ~eCl~ and 3.0 g triethanolamine (catalyst)
were used. The FeC13-content determined colorimetrically in
the reaction solution averaged 0.25 wgt ~. m e experiment
was run over a period of 6 days and dichloroethane was ob-
tained at an hourly rate of 268 g.
Product A obtained in the condenser was analyzed and the
following results were obtained:
~-od~ t
~_ . . . , ... . _ .
C2H5Cl < 0.002
1,2-EDC 9~.65
1,1,2-ETC 0.~3
HCl 0.007
Further components O.01
,
Example 7
a) 2 kg 1,2-dichloroethane and 2.1 g iron(III)chloride were
placed in a 2 liter round flask provided ~ith an agita-
tor, dropping ~unnel and reflux condenser, The mixture
was heated ~o boiling while stirring and admixed drop-
wise with 002 g ammonia which was dissol~ed in 58 g dl-
5i7
chloroethane; this corresponded to a total catalyst
quantity of 2.3 g. The mixture was boiled ~wnder re-
flux for a further 5 hours and the FeCl3-content in
the solution was determined colorimetrically; it
was 0.11 wgt %.
b) The mixture of dichloroethane and catalyst was intro-
duced into the loop reactor described in Example 1.
Next, about 60 l/h each o~ chlorine and ethylene were
introduced together with about 5 l/h air. The experi-
~ent was run over a period of 8 days ~nd dichloro-
ethane was obtained at an hourly rate of 273 g.
Product A obtained in the condenser was analyzed and
the following results were obtained:
Product A (Wgt ~)
. , .. - . . I
C2H5Cl < 0.002
1,2-EDC 99.51
1,1,2-ETC 0.48
HCl 0.002
Further compo~ents OffOO9
Example 8
a) The procedure was as in Example 7 a) but 1.5 kg 1,2-di-
chloroethane and 12 g FeCl3 were heated to boiling while
stirring. Next, the mixture was admixed dropwise first
with a solution of 2.7 g hydrogen chloride in 750 g di-
chloroethane and then with a solution of 1.26 g ~H3 in
273 g dichloroethane~ After cooling, the reaction mix-
ture was ~iltered and the filter residue dried. 14.4 g
dry catalyst was obtained.
a~ 7
b) To produce 1~2-dichloroethane, 4 g of the catalyst
made as described under a~ and 2 g ~eC13 were sus-
pended in 2.7 kg 1,2-dichloroethane, the suspension
was concentrated to a volume o~ about 2 liters and
introduced into the loop reactor described in Example 1.
The loop reactor was ~ed per hour with about 60 liters
each o~ chlorine and ethylene and 15 liters air and
the reaction was initiated under the conditions des-
cribed in Example 1. The experiment was run over a
period of 6 days and 1,2-dichloroethane was obtained
at an hourly rate of 266 g. The ~eCl3-content in the
reaction solution determined colorimetrically averaged
0~15 wgt %.
Product A obtained in the condenser and reactor liquid B
were analyzed after the reaction had been terminated and the
~ollowing results were obtained.
Product A (Wgt %) Product B (Wgt %)
~_
C2H5 l 0.004 0.006
1,2-EDC 99.93 99.74
1,1,2-ETC 0.06 0.23
HCl 0.002 0.03
rur~her c~m~e.tsO.003 _ . _ _
Example 9
Steel specimens were tested for corrosion under the condi-
tions of the process of this invention. To this end, 4 speci-
mens were exposed at 4 places in a co~mercial rsactor for mak-
ing 1,2-dichloroethane. The specimens were taken from the re-
actor at intervals of 20 days and the material removed there-
12
from by corrosion was determ~ned.
~ The average corrosion rate determined for
unalloyed steel was less than 0.05 mm per annum in the pro-
cess carried out with the FeCl3/NH3-catalyst of this in-
vention at a reaction temperature maintained at 100-110C,
In the prooess carried out in known marmer with the use
exclusively of ~eCl3 as the catalyst, the average corro-
sion rate determined for unalloyed steel was 0.43 mm per
annum.
13
