CA1221708A - Process for making 1,2-dichloroethane - Google Patents
Process for making 1,2-dichloroethaneInfo
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- CA1221708A CA1221708A CA000414663A CA414663A CA1221708A CA 1221708 A CA1221708 A CA 1221708A CA 000414663 A CA000414663 A CA 000414663A CA 414663 A CA414663 A CA 414663A CA 1221708 A CA1221708 A CA 1221708A
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- dichloroethane
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- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C17/00—Preparation of halogenated hydrocarbons
- C07C17/013—Preparation of halogenated hydrocarbons by addition of halogens
- C07C17/02—Preparation of halogenated hydrocarbons by addition of halogens to unsaturated hydrocarbons
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- Organic Chemistry (AREA)
- Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
- Low-Molecular Organic Synthesis Reactions Using Catalysts (AREA)
- Acyclic And Carbocyclic Compounds In Medicinal Compositions (AREA)
Abstract
PROCESS FOR MAKING 1,2-DICHLOROETHANE
ABSTRACT OF THE DISCLOSURE
The disclosure relates to a process for making 1,2-di-chloroethane by reacting ethylene and chlorine in a reac-tion zone at a temperature of about 75 to 200°C, under a pressure of about 1 to 15 bars and over a mean period of time of about 1 to 15 hours; the reaction zone has a liquid medium containing chlorinated C2-hydrocarbons circulated therein and contains a chlorination-inducing catalyst. More particularly, the 1,2-dichloroethane is produced inside a double loop reactor.
ABSTRACT OF THE DISCLOSURE
The disclosure relates to a process for making 1,2-di-chloroethane by reacting ethylene and chlorine in a reac-tion zone at a temperature of about 75 to 200°C, under a pressure of about 1 to 15 bars and over a mean period of time of about 1 to 15 hours; the reaction zone has a liquid medium containing chlorinated C2-hydrocarbons circulated therein and contains a chlorination-inducing catalyst. More particularly, the 1,2-dichloroethane is produced inside a double loop reactor.
Description
~2Z~708 HOE 81/H 040 The present invention relates to a process for making 1,2-dichloroethane by reacting ethylene and chlorine in it-quid 1,2-dichloroethane in the presence of a customary cay Tolstoy, technically beneficial use being made of the react lion heat which is evolved during the reaction and the us-desirable formation ox higher chlorinated products 9 such as in-, twitter and pentachloroethane, inside the reactor being extensively avoided as well as the accumulation of such pro-ducts therein.
The chlorination of olefins by means of chlorine is known to tare place as exothermal reaction. In the event of ethylene being chlorinated with chlorine 2200 kJ heat is evolved per kg 1,2-dichloroethane. This means in other words that a quantity of heat sufficient for the generation of about 1 ton steam is evolved upon the production of 1 ton 1,2-dichloroethane. It the processes or making dichloro-ethanes described heretofore, the reaction heat was either abstracted by cooling the reactor or used partially for directly evaporating and expelling the dichloroethane formed during the reaction from the reaction mixture or reactor, and in some case or other partially or completely but exclusively for rectifying 1,2-dichloroethane made by another process.
me process described in DEEPS 15 43 108, for example, provides or the combined abstraction of the reaction heat which is evolved during the chlorination of ethylene with chlorine. More especially, the iron reactor used for carry-in out the reaction is provided with a cooling means which is supplied with cooling water permitting the neat evolved during the reaction to be abstracted and a predetermined reaction temperature of 50 up to 70C to be maintained.
The reaction temperature is lower than the boiling point of 1,2-dichloroethane and is controlled during the react lion so as to ensure continuous removal ox the 1,2-dichlo-Raytheon formed in vapor Norm from the reaction chamber, While no higher chlorinated products accumulate in this process inside the reactor, the fact remains that 3.3 %
trichloroethane is being formed and that the reaction heat remains unutilized as it is necessary or condensed Dow-chloroethane to be freed from the byproduct just specified.
A process basically the same as that described in DEEPS 15 43 108 has been disclosed in DEMOS 29 35 8849 this latter process comprising: during the reaction, circulating the material placed in the reactor through an annular con-dull communicating with the reactor and separating vaporous products issuing at the head of the reactor in a rectifying column with recovery of 1,2-dichloroethane. Higher boiling by-products are recycled from the base portion of the fee-tidying column to the reactor; this however is disadvant-ages as reaction product which is removed discontinuously from the column base portion is required Jo be worked up so-portly and as the reaction heat evolved can be utilized partially only A further process for making ethylene chloride (cf.
DEMOS 24 27 045) provides:
a) or ethylene and chlorine to be introduced into a reaction zone maintained under elevated pressure and having a liquid medium containing chlorinated C2 ho ~2~2~7~1~
drocarbons or mixtures thereon circulated therein, the medium being kept at a temperature lower than its evaporation temperature under the pressure pro-veiling inside the reaction zone with formation of crude liquid ethylene dichlorides b) or the crude liquid ethylene dichlorides to be intro-duped together with the circulated medium into a zone maintained under lower pressure than the reaction zone, i.e. under a pressure and at a temperature at which the crude ethylene dichlorides becomes evaporated under the action ox the reaction heat set tree during the reaction ox chlorine with ethylene, and c) for vaporous crude ethylene dichlvride to be intro duped into a rectifying zone and to be rectified there-in with the aid of the reaction heat set tree during the reaction of chlorine with ethylene, purified ethyl tone dichlorides being removed from the rectifying zone, and product obtained in the base portion of the recta-vying column being recycled to the above zone main-twined under lower pressure, and combined with the medium circulated therein.
Recycling the base product into the reactor is disk advantageous inasmuch as the circulated liquid medium be-comes enriched with higher boiling chlorination products which must successively be removed therefrom. As indicated in Example 4 of DEMOS 24 27 045 the circulated medium con twins about 60 % 1,1,2-trichloroethane. This means in other words that the chlorination reaction described heretofore is accompanied by the formation ox considerable proportions I
of undesirable by-products.
It has therefore been desirable to improve the processes described heretofore so as to extensively avoid the formation of by-products and provide for an optimum utilization of the evolved reaction heat. This is extensively achieved by a process for making 1,2-dichloroethane by reacting ethylene and chlorine in a reaction zone having a liquid medium containing chlorinated C2-hydrocarbons circulated therein at a temperature lower than the evaporation temperature of said medium under the pressure prevailing inside the reaction zone, in the presence of a customary chlorination-inducing catalyst and optionally an inhibitor reducing the formation of by-products so as to obtain crude 1,2-dichloroethane, removing the crude dichloroethane from the reaction zone and purifying it in a separate downstream fractionating zone, the process comprising:
a introducing approximately equimolar proportions of ethylene and chlorine into the circulated liquid medium; intensively mixing the whole in a mixing zone and then reacting the mix-lure in a reaction zone at a temperature of about 75 up to 200C under a pressure of about 1 up to 15 bars, the mean sojourn time of the reaction mixture in the mixing zone and reaction zone being equal to about 1 to 15 hours;
b) removing a portion of the liquid reaction mixture from the reaction zone and subdividing said portion into two partial streams, passing one of these partial streams through a heat Lo 8 exchanger for abstraction of calorific energy therefrom and for reduction of its initial temperature and recycling it to the mixing and reaction zone; introducing the second partial stream in-to an expansion vessel and evaporating therein a quantity of reaction product corresponding to the quantity of reaction product formed in the reaction zone and optionally also a proportion of 1,2-dichloroethane original-in from a third source and being introduced into the reaction zone, introducing resulting vaporous matter into a fraction-cling column and recycling unevaporated liquid matter of the second partial stream into the liquid medium circulated in the mixing and reaction zone; and c) separating distillatively 1,2-dichloroethane from the vapor-out matter introduced into the fractionating column with the use of a portion of the heat energy transferred inside the heat exchanger and removing the 1,2-dichloroethane overhead, higher chlorinated products being obtained in the columns base portion from which they are removed and worked up separately. The present invention now provides an improved form of carrying out the process as discussed above which is effected in a double loop reactor.
The improved process of -the present invention for making 1,2-dichloroethane by reacting ethylene and chlorine in a reaction zone having a liquid medium containing chlorinated C2-hydrocarbons circulated therein in the presence of a customary chlorination-inducing catalyst and optionally an inhibitor reducing the formation ox by pro-ducts, wherein a) approximately equimolar proportions of ethylene and chlorine are introduced into the circulated squid medium, the whole is mixed in a mixing zone and the mixture is reacted in a reaction zone at a temperature of about 75 up to 200C under a pressure of about 1 up to 15 bars, the mean sojourn time of the reaction mixture in the mixing zone and reaction zone being equal to about 1 to 15 hours; and wherein b) a portion of the liquid reaction mixture is removed from the reaction zone and subdivided into two partial streams, of which one is passed through a heat exchanger for abstraction of caloric energy there-from and for reduction of its initial temperature, and then recycled to the mixing and reaction zone whilst the second partial stream is introduced into an expand soon vessel and a proportion of reaction product corresponding to the quantity ox reaction product formed in the reaction zone is evaporated from said second partial stream, the resulting vaporous matter is introduced into a fractionating column and 1,2-dichloroethane is distillatively separated, and unevaporated liquid matter of the second partial stream is recycled into the liquid medium circulated in the mixing and reaction zone, comprises: preparing ~2~L70~3 the 1,2-dichloroethane inside a double loop reactor by A) introducing ethylene through line (1) and chlorine gas through line (2) in-to the ascending portion ox loop (I) at a level below the mixing zone (3) form-in part of the ascending polo boon and finely distributing them in the liquid medium circulated through loop (I), and by reacting the reaction components in reaction zone (4) and sojourn zone (5), respectively upstream ox the mixing zone (3) and B) removing from loop (I) two partial streams of reaction mixture, of which one is introduced through line (8) into heat exchanger (10) for abstraction of calorific energy therefrom and recycled through line (9) into the descending portion of loop (I) whilst top second partial stream is introduced into loop (II) integrally connected to loop (I) and into expansion zone (6) forming part of loop cycle (II), in which a proportion of reaction product corresponding to the quantity of reaction product formed in reaction zone (4) is evaporated from said second partial stream, the resulting vaporous matter is delivered through line (7) to the fractionating column, and unevaporated , 25 liquid matter of the second partial stream is recycled through the descending portion of loop (II) into the mixing zone (~) and reaction zone (4), respectively of loop (I).
A preferred feature of the present process provides or inert gases or low-boiling hydrocarbons such as ethyl chloride being contained in the reaction mixture to be removed from sojourn zone (5) through line (11) or from the descending portion ox loop (I) through line (12).
The following statements are intended further to ill-strata the process of this invention.
It is possible for the chlorine and ethylene reactants to be diluted with inert gases. The chlorine can be intro-duped into the mixing zone in the form of liquid or gaseous matter, liquid chlorine being preferably evaporated ahead of the reactor in a heat exchanger with the aid of a port lion of the reaction enthalpy. Iron-III chloride should preferably be used as a catalyst and oxygen should preferably be used as an agent inhibiting the formation of byproducts.
The liquid medium is circulated through the reactor in accordance with the principle underlying a thermosiphon or mammoth pump. Inside the mixing zone, the liquid medium should conveniently be circulated with a velocity of at least 0.1 m/second. The circulation for effecting ova-proration of product can also be effected in accordance with the principle underlying a thermosiphon. The heat exchanger may be arranged so as to form an integral part of the product cycles, or can be fed separately by means ox a pump.
The process of this invention will now be described with reference to the accompanying drawing.
Liquid 1,2-dichloroethane it introduced into a double loop reactor comprising loop cycles I and II. Next, ethylene is introduced through line 1 and chlorine gas is introduced through line 2 to effect circulation of the 1,2-dichloro-ethanes in accordance with the principle underlying a mammoth pump. Once the ethylene has commenced reacting with the chlorine gas, the reaction being started inside packed mixing zone 3 and completed inside reaction zone 4 and sojourn zone 5, additional buoyant forces occur in the ascending portion of loop I, which originate from the react lion heat set free. The temperature prevailing in loop cycle I is slightly lower than the boiling temperature of 1,2-dichloroethane inside the reactor under the pressure prevailing. Inert gases which may be found to be present in loop I are removed through lines 11 and 12, and cooled in a cooler (not shown in the drawing) in order to condense vaporous 1,2-~ichloroethane which may have been carried along. Uncondensed gay is allowed to escape and worked up in known fashion. By regulating the flow of inert gas and the quantity of gas which is removed it is possible to establish the pressure desired to prevail in loop I.
To remove produced 1,2-dichloroethane from loop I, the stream ox liquid matter is subdivided into two partial streams; one of these two partial streams is passed through line 8 into heat exchanger 10 for abstraction of heat energy therein and is then recycled through line 9 into the descending portion of loop I, whilst the other is introduced into loop II which is integrally connected to loop I and into an expansion zone 6, in which a quantity of reaction product corresponding to the quantity of react lion product formed in reaction zone 4 is evaporated, the ~.~2~L70~
resulting vaporous matter being introduced through line 7 into a fractionating column (not shown in the drawing), whilst unevaporated liquid matter of the second partial stream is recycled through the descending portion of loop II into mixing zone 3 and reaction zone 4, respectively. Inert gases or low-boiling hydrocarbons, such as ethyl chloride, are taken from sojourn zone 5 through line 11 or from the descending portion of loop I through line 12.
The process of this invention offers technically beneficial effects which are the same as those offered by the process discussed above. They originate from the continuous removal of a portion of liquid matter from the reactor and its division into two partial streams of which one permits reaction heat to be continuously recovered, and the other is partially evaporated, the evaporated portion being worked up in the fractionating column; as a result, it is ensured that catalyst-free crude dichloroethane is introduced into the fractionating column, which however also receives the higher chlorinated by-products together with the evaporated matter. In other words, by-products are substantially not liable to accumulate in loop I. In the processes described heretofore, such by-product accumulation gives rise to the concentration of higher chlorinated by-products which ultimately must invariably be removed from the reactor Needless to say catalyst losses are associated therewith which naturally affect the economy of these processes. Under the reaction conditions used in accordance with this invention, ~L22~ 8 the mean sojourn -time of all reactants inside the reactor is shortened so that undesirable side-reactions involving by-product formation are extensively avoided.
The present process also permits use to be made of feed materials contaminated with inert gases which normally entail difficulties in the decontamination of dichloroethane in the fractionating column. In accordance with this invention, the inert gases are already removed from loop I via inert gas removal lines 11 and 12 so that they are definitely prevented from affecting the work-up of the reaction mixture.
The present process finally compares favorably with that discussed above by the use of a double loop reactor in which the reaction mixture is continuously circulated through loops I
and II in accordance with the principle underlying a thermosiphon or mammoth pump. In other words, no special pumps permitting the reaction mixture to be introduced into, or to be taken from !' the reactor have to be used which naturally means an economy of energy.
Example A reactor such as that shown in the drawing with a capacity of about 15 1 contained about 15 kg 1,2-dichloroethane and 0.1 % iron chloride as a catalyst. 110 l/h ethylene was introduced through line 1 and about 110 l/h chlorine and 10 l/h air were admitted through line 2. The temperature in the reactor was about 115C, the pressure 7~3 prevailing in sojourn zone 5 was about 3 bars and the pressure difference between sojourn zone 5 and expansion zone 6 was about 0.6 bar.
The gas coming from the reactor was taken prom sojourn zone 5 through line 11. In a cooling trap, it was freed at -30C from condensable matter. 480.1 g/h vaporous dip chloroethane was taken from the expansion vessel 6 through line 7 and condensed.
About 200 l/h reactor liquid was pumped through lines 8 and 9 for abstraction of reaction heat. Heat abstracted in heat exchanger 10 was used for distilling dichloroethane at a base temperature of the respective column of 80 to 85C.
After an operation period of 48 hours, the Dow-chloroethane removed was analyzed and found to contain:
C2H5Cl 0.0024 wit 1,1-EDC 00002 wit %
1,2-EDC 99.86 wit %
1,1,2-ETC 0.13 wit %
The chlorination of olefins by means of chlorine is known to tare place as exothermal reaction. In the event of ethylene being chlorinated with chlorine 2200 kJ heat is evolved per kg 1,2-dichloroethane. This means in other words that a quantity of heat sufficient for the generation of about 1 ton steam is evolved upon the production of 1 ton 1,2-dichloroethane. It the processes or making dichloro-ethanes described heretofore, the reaction heat was either abstracted by cooling the reactor or used partially for directly evaporating and expelling the dichloroethane formed during the reaction from the reaction mixture or reactor, and in some case or other partially or completely but exclusively for rectifying 1,2-dichloroethane made by another process.
me process described in DEEPS 15 43 108, for example, provides or the combined abstraction of the reaction heat which is evolved during the chlorination of ethylene with chlorine. More especially, the iron reactor used for carry-in out the reaction is provided with a cooling means which is supplied with cooling water permitting the neat evolved during the reaction to be abstracted and a predetermined reaction temperature of 50 up to 70C to be maintained.
The reaction temperature is lower than the boiling point of 1,2-dichloroethane and is controlled during the react lion so as to ensure continuous removal ox the 1,2-dichlo-Raytheon formed in vapor Norm from the reaction chamber, While no higher chlorinated products accumulate in this process inside the reactor, the fact remains that 3.3 %
trichloroethane is being formed and that the reaction heat remains unutilized as it is necessary or condensed Dow-chloroethane to be freed from the byproduct just specified.
A process basically the same as that described in DEEPS 15 43 108 has been disclosed in DEMOS 29 35 8849 this latter process comprising: during the reaction, circulating the material placed in the reactor through an annular con-dull communicating with the reactor and separating vaporous products issuing at the head of the reactor in a rectifying column with recovery of 1,2-dichloroethane. Higher boiling by-products are recycled from the base portion of the fee-tidying column to the reactor; this however is disadvant-ages as reaction product which is removed discontinuously from the column base portion is required Jo be worked up so-portly and as the reaction heat evolved can be utilized partially only A further process for making ethylene chloride (cf.
DEMOS 24 27 045) provides:
a) or ethylene and chlorine to be introduced into a reaction zone maintained under elevated pressure and having a liquid medium containing chlorinated C2 ho ~2~2~7~1~
drocarbons or mixtures thereon circulated therein, the medium being kept at a temperature lower than its evaporation temperature under the pressure pro-veiling inside the reaction zone with formation of crude liquid ethylene dichlorides b) or the crude liquid ethylene dichlorides to be intro-duped together with the circulated medium into a zone maintained under lower pressure than the reaction zone, i.e. under a pressure and at a temperature at which the crude ethylene dichlorides becomes evaporated under the action ox the reaction heat set tree during the reaction ox chlorine with ethylene, and c) for vaporous crude ethylene dichlvride to be intro duped into a rectifying zone and to be rectified there-in with the aid of the reaction heat set tree during the reaction of chlorine with ethylene, purified ethyl tone dichlorides being removed from the rectifying zone, and product obtained in the base portion of the recta-vying column being recycled to the above zone main-twined under lower pressure, and combined with the medium circulated therein.
Recycling the base product into the reactor is disk advantageous inasmuch as the circulated liquid medium be-comes enriched with higher boiling chlorination products which must successively be removed therefrom. As indicated in Example 4 of DEMOS 24 27 045 the circulated medium con twins about 60 % 1,1,2-trichloroethane. This means in other words that the chlorination reaction described heretofore is accompanied by the formation ox considerable proportions I
of undesirable by-products.
It has therefore been desirable to improve the processes described heretofore so as to extensively avoid the formation of by-products and provide for an optimum utilization of the evolved reaction heat. This is extensively achieved by a process for making 1,2-dichloroethane by reacting ethylene and chlorine in a reaction zone having a liquid medium containing chlorinated C2-hydrocarbons circulated therein at a temperature lower than the evaporation temperature of said medium under the pressure prevailing inside the reaction zone, in the presence of a customary chlorination-inducing catalyst and optionally an inhibitor reducing the formation of by-products so as to obtain crude 1,2-dichloroethane, removing the crude dichloroethane from the reaction zone and purifying it in a separate downstream fractionating zone, the process comprising:
a introducing approximately equimolar proportions of ethylene and chlorine into the circulated liquid medium; intensively mixing the whole in a mixing zone and then reacting the mix-lure in a reaction zone at a temperature of about 75 up to 200C under a pressure of about 1 up to 15 bars, the mean sojourn time of the reaction mixture in the mixing zone and reaction zone being equal to about 1 to 15 hours;
b) removing a portion of the liquid reaction mixture from the reaction zone and subdividing said portion into two partial streams, passing one of these partial streams through a heat Lo 8 exchanger for abstraction of calorific energy therefrom and for reduction of its initial temperature and recycling it to the mixing and reaction zone; introducing the second partial stream in-to an expansion vessel and evaporating therein a quantity of reaction product corresponding to the quantity of reaction product formed in the reaction zone and optionally also a proportion of 1,2-dichloroethane original-in from a third source and being introduced into the reaction zone, introducing resulting vaporous matter into a fraction-cling column and recycling unevaporated liquid matter of the second partial stream into the liquid medium circulated in the mixing and reaction zone; and c) separating distillatively 1,2-dichloroethane from the vapor-out matter introduced into the fractionating column with the use of a portion of the heat energy transferred inside the heat exchanger and removing the 1,2-dichloroethane overhead, higher chlorinated products being obtained in the columns base portion from which they are removed and worked up separately. The present invention now provides an improved form of carrying out the process as discussed above which is effected in a double loop reactor.
The improved process of -the present invention for making 1,2-dichloroethane by reacting ethylene and chlorine in a reaction zone having a liquid medium containing chlorinated C2-hydrocarbons circulated therein in the presence of a customary chlorination-inducing catalyst and optionally an inhibitor reducing the formation ox by pro-ducts, wherein a) approximately equimolar proportions of ethylene and chlorine are introduced into the circulated squid medium, the whole is mixed in a mixing zone and the mixture is reacted in a reaction zone at a temperature of about 75 up to 200C under a pressure of about 1 up to 15 bars, the mean sojourn time of the reaction mixture in the mixing zone and reaction zone being equal to about 1 to 15 hours; and wherein b) a portion of the liquid reaction mixture is removed from the reaction zone and subdivided into two partial streams, of which one is passed through a heat exchanger for abstraction of caloric energy there-from and for reduction of its initial temperature, and then recycled to the mixing and reaction zone whilst the second partial stream is introduced into an expand soon vessel and a proportion of reaction product corresponding to the quantity ox reaction product formed in the reaction zone is evaporated from said second partial stream, the resulting vaporous matter is introduced into a fractionating column and 1,2-dichloroethane is distillatively separated, and unevaporated liquid matter of the second partial stream is recycled into the liquid medium circulated in the mixing and reaction zone, comprises: preparing ~2~L70~3 the 1,2-dichloroethane inside a double loop reactor by A) introducing ethylene through line (1) and chlorine gas through line (2) in-to the ascending portion ox loop (I) at a level below the mixing zone (3) form-in part of the ascending polo boon and finely distributing them in the liquid medium circulated through loop (I), and by reacting the reaction components in reaction zone (4) and sojourn zone (5), respectively upstream ox the mixing zone (3) and B) removing from loop (I) two partial streams of reaction mixture, of which one is introduced through line (8) into heat exchanger (10) for abstraction of calorific energy therefrom and recycled through line (9) into the descending portion of loop (I) whilst top second partial stream is introduced into loop (II) integrally connected to loop (I) and into expansion zone (6) forming part of loop cycle (II), in which a proportion of reaction product corresponding to the quantity of reaction product formed in reaction zone (4) is evaporated from said second partial stream, the resulting vaporous matter is delivered through line (7) to the fractionating column, and unevaporated , 25 liquid matter of the second partial stream is recycled through the descending portion of loop (II) into the mixing zone (~) and reaction zone (4), respectively of loop (I).
A preferred feature of the present process provides or inert gases or low-boiling hydrocarbons such as ethyl chloride being contained in the reaction mixture to be removed from sojourn zone (5) through line (11) or from the descending portion ox loop (I) through line (12).
The following statements are intended further to ill-strata the process of this invention.
It is possible for the chlorine and ethylene reactants to be diluted with inert gases. The chlorine can be intro-duped into the mixing zone in the form of liquid or gaseous matter, liquid chlorine being preferably evaporated ahead of the reactor in a heat exchanger with the aid of a port lion of the reaction enthalpy. Iron-III chloride should preferably be used as a catalyst and oxygen should preferably be used as an agent inhibiting the formation of byproducts.
The liquid medium is circulated through the reactor in accordance with the principle underlying a thermosiphon or mammoth pump. Inside the mixing zone, the liquid medium should conveniently be circulated with a velocity of at least 0.1 m/second. The circulation for effecting ova-proration of product can also be effected in accordance with the principle underlying a thermosiphon. The heat exchanger may be arranged so as to form an integral part of the product cycles, or can be fed separately by means ox a pump.
The process of this invention will now be described with reference to the accompanying drawing.
Liquid 1,2-dichloroethane it introduced into a double loop reactor comprising loop cycles I and II. Next, ethylene is introduced through line 1 and chlorine gas is introduced through line 2 to effect circulation of the 1,2-dichloro-ethanes in accordance with the principle underlying a mammoth pump. Once the ethylene has commenced reacting with the chlorine gas, the reaction being started inside packed mixing zone 3 and completed inside reaction zone 4 and sojourn zone 5, additional buoyant forces occur in the ascending portion of loop I, which originate from the react lion heat set free. The temperature prevailing in loop cycle I is slightly lower than the boiling temperature of 1,2-dichloroethane inside the reactor under the pressure prevailing. Inert gases which may be found to be present in loop I are removed through lines 11 and 12, and cooled in a cooler (not shown in the drawing) in order to condense vaporous 1,2-~ichloroethane which may have been carried along. Uncondensed gay is allowed to escape and worked up in known fashion. By regulating the flow of inert gas and the quantity of gas which is removed it is possible to establish the pressure desired to prevail in loop I.
To remove produced 1,2-dichloroethane from loop I, the stream ox liquid matter is subdivided into two partial streams; one of these two partial streams is passed through line 8 into heat exchanger 10 for abstraction of heat energy therein and is then recycled through line 9 into the descending portion of loop I, whilst the other is introduced into loop II which is integrally connected to loop I and into an expansion zone 6, in which a quantity of reaction product corresponding to the quantity of react lion product formed in reaction zone 4 is evaporated, the ~.~2~L70~
resulting vaporous matter being introduced through line 7 into a fractionating column (not shown in the drawing), whilst unevaporated liquid matter of the second partial stream is recycled through the descending portion of loop II into mixing zone 3 and reaction zone 4, respectively. Inert gases or low-boiling hydrocarbons, such as ethyl chloride, are taken from sojourn zone 5 through line 11 or from the descending portion of loop I through line 12.
The process of this invention offers technically beneficial effects which are the same as those offered by the process discussed above. They originate from the continuous removal of a portion of liquid matter from the reactor and its division into two partial streams of which one permits reaction heat to be continuously recovered, and the other is partially evaporated, the evaporated portion being worked up in the fractionating column; as a result, it is ensured that catalyst-free crude dichloroethane is introduced into the fractionating column, which however also receives the higher chlorinated by-products together with the evaporated matter. In other words, by-products are substantially not liable to accumulate in loop I. In the processes described heretofore, such by-product accumulation gives rise to the concentration of higher chlorinated by-products which ultimately must invariably be removed from the reactor Needless to say catalyst losses are associated therewith which naturally affect the economy of these processes. Under the reaction conditions used in accordance with this invention, ~L22~ 8 the mean sojourn -time of all reactants inside the reactor is shortened so that undesirable side-reactions involving by-product formation are extensively avoided.
The present process also permits use to be made of feed materials contaminated with inert gases which normally entail difficulties in the decontamination of dichloroethane in the fractionating column. In accordance with this invention, the inert gases are already removed from loop I via inert gas removal lines 11 and 12 so that they are definitely prevented from affecting the work-up of the reaction mixture.
The present process finally compares favorably with that discussed above by the use of a double loop reactor in which the reaction mixture is continuously circulated through loops I
and II in accordance with the principle underlying a thermosiphon or mammoth pump. In other words, no special pumps permitting the reaction mixture to be introduced into, or to be taken from !' the reactor have to be used which naturally means an economy of energy.
Example A reactor such as that shown in the drawing with a capacity of about 15 1 contained about 15 kg 1,2-dichloroethane and 0.1 % iron chloride as a catalyst. 110 l/h ethylene was introduced through line 1 and about 110 l/h chlorine and 10 l/h air were admitted through line 2. The temperature in the reactor was about 115C, the pressure 7~3 prevailing in sojourn zone 5 was about 3 bars and the pressure difference between sojourn zone 5 and expansion zone 6 was about 0.6 bar.
The gas coming from the reactor was taken prom sojourn zone 5 through line 11. In a cooling trap, it was freed at -30C from condensable matter. 480.1 g/h vaporous dip chloroethane was taken from the expansion vessel 6 through line 7 and condensed.
About 200 l/h reactor liquid was pumped through lines 8 and 9 for abstraction of reaction heat. Heat abstracted in heat exchanger 10 was used for distilling dichloroethane at a base temperature of the respective column of 80 to 85C.
After an operation period of 48 hours, the Dow-chloroethane removed was analyzed and found to contain:
C2H5Cl 0.0024 wit 1,1-EDC 00002 wit %
1,2-EDC 99.86 wit %
1,1,2-ETC 0.13 wit %
Claims (7)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A process for producing 1,2-dichloroethane using a reactor comprising:
a mixing zone, a reaction zone and a sojourn zone in that order:
a first loop for recycling a reaction medium, the loop connecting an exit and an entrance of the sojourn zone and having a descending portion from the exit and an ascending portion to the entrance;
the ascending portion of the first loop comprising the mixing zone and the reaction zone forming a part thereof, an ethylene inlet and a chlorine inlet each upstream of the mixing zone;
a second loop connecting the descending portion of the first loop at a first connecting part near the exit from the sojourn zone and the descending portion of the first loop at a second connecting part downstream of the first connecting part of the second loop, the second loop including an expansion zone;
a fractionating column connected to the expansion zone for fractionating vaporous compounds delivered from the expansion zone; and a stream line connects the descending portion of the first loop at a first connecting part near the exit from the sojourn zone and the descending portion of the first loop at a second connecting part downstream of the first connecting part of the stream line, the stream line including a heat exchanger, which process comprises:
(1) introducing approximately equimolar amounts of ethylene and chlorine from the ethylene inlet and the chlorine inlet, respectively, to the mixing zone having a liquid medium containing, circulated therein, chlorinated C2-hydrocarbons and a chlorination-inducing catalyst and finally distributing the reactants in the liquid medium; reacting the reactants in the reaction zone at a temperature of about 75 to 200°C under a pressure of about 1 to 15 bars; the main sojourn time of the reaction mixture in the mixing zone, reaction zone and the sojourn zone being about 1 to 15 hours, (2) removing a portion of the reaction mixture from the first loop and passing it through the stream line via the heat exchanger for abstraction of calorific energy therefrom and for reduction of the initial temperature, and then recycling the cooled portion to the first loop, (3) removing another portion of the reaction mixture from the first loop through the second loop into the expansion zone, evaporating a proportion of the reaction product corresponding to the quantity of the reaction product formed in the reaction zone and the sojourn zone, separating vaporous components from the expansion zone into the fractionating column, distillative-ly separating 1,2-dichloroethane from the fractionating column, recycling unvaporized liquid components in the expansion zone through the second loop into the liquid medium circulated in the first loop.
a mixing zone, a reaction zone and a sojourn zone in that order:
a first loop for recycling a reaction medium, the loop connecting an exit and an entrance of the sojourn zone and having a descending portion from the exit and an ascending portion to the entrance;
the ascending portion of the first loop comprising the mixing zone and the reaction zone forming a part thereof, an ethylene inlet and a chlorine inlet each upstream of the mixing zone;
a second loop connecting the descending portion of the first loop at a first connecting part near the exit from the sojourn zone and the descending portion of the first loop at a second connecting part downstream of the first connecting part of the second loop, the second loop including an expansion zone;
a fractionating column connected to the expansion zone for fractionating vaporous compounds delivered from the expansion zone; and a stream line connects the descending portion of the first loop at a first connecting part near the exit from the sojourn zone and the descending portion of the first loop at a second connecting part downstream of the first connecting part of the stream line, the stream line including a heat exchanger, which process comprises:
(1) introducing approximately equimolar amounts of ethylene and chlorine from the ethylene inlet and the chlorine inlet, respectively, to the mixing zone having a liquid medium containing, circulated therein, chlorinated C2-hydrocarbons and a chlorination-inducing catalyst and finally distributing the reactants in the liquid medium; reacting the reactants in the reaction zone at a temperature of about 75 to 200°C under a pressure of about 1 to 15 bars; the main sojourn time of the reaction mixture in the mixing zone, reaction zone and the sojourn zone being about 1 to 15 hours, (2) removing a portion of the reaction mixture from the first loop and passing it through the stream line via the heat exchanger for abstraction of calorific energy therefrom and for reduction of the initial temperature, and then recycling the cooled portion to the first loop, (3) removing another portion of the reaction mixture from the first loop through the second loop into the expansion zone, evaporating a proportion of the reaction product corresponding to the quantity of the reaction product formed in the reaction zone and the sojourn zone, separating vaporous components from the expansion zone into the fractionating column, distillative-ly separating 1,2-dichloroethane from the fractionating column, recycling unvaporized liquid components in the expansion zone through the second loop into the liquid medium circulated in the first loop.
2. A process as claimed in claim 1, which is carried out using the reactor in which the first and second loops are inte-grally formed.
3. A process as claimed in claim 2, which further comprises cooling inert gases or low boiling hydrocarbons removed from the sojourn zone or from the descending portion of the first loop.
4. A process as claimed in claim 1, 2 or 3, wherein liquid chlorine is evaporated before being introduced into the mixing zone in the heat exchanger.
5. A process as claimed in claim 1, 2 or 3, wherein ferris chloride is used as the chlorination inducing catalyst.
6. A process as claimed in claim 1, 2 or 3, wherein the reaction is carried out in the presence of oxygen as an agent inhibiting the formation of by-products.
7. A process as claimed in claim 1, 2 or 3, wherein the liquid medium is circulated in accordance with the principle underlaying a thermosiphon or mammoth pump.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DEP3146246.4 | 1981-11-21 | ||
| DE19813146246 DE3146246A1 (en) | 1981-11-21 | 1981-11-21 | METHOD FOR PRODUCING 1,2-DICHLORETHANE |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1221708A true CA1221708A (en) | 1987-05-12 |
Family
ID=6146933
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000414663A Expired CA1221708A (en) | 1981-11-21 | 1982-11-02 | Process for making 1,2-dichloroethane |
Country Status (14)
| Country | Link |
|---|---|
| EP (1) | EP0080098B1 (en) |
| JP (1) | JPS5892626A (en) |
| AR (1) | AR231831A1 (en) |
| AU (1) | AU564581B2 (en) |
| BR (1) | BR8206726A (en) |
| CA (1) | CA1221708A (en) |
| DD (1) | DD206775A5 (en) |
| DE (2) | DE3146246A1 (en) |
| ES (1) | ES517343A0 (en) |
| HU (1) | HU191194B (en) |
| MX (1) | MX161860A (en) |
| NO (1) | NO155575C (en) |
| SU (1) | SU1480758A3 (en) |
| ZA (1) | ZA828536B (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7504077B2 (en) * | 1999-03-12 | 2009-03-17 | Uhde Gmbh | Method of producing ethylene (di) chloride (EDC) |
Families Citing this family (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE3340624C1 (en) * | 1983-11-10 | 1984-10-11 | Dynamit Nobel Ag, 5210 Troisdorf | Process for the preparation of 1,2-dichloroethane from ethylene and chlorine gas |
| DE3445896C1 (en) * | 1984-12-15 | 1986-04-10 | Dynamit Nobel Ag, 5210 Troisdorf | Process for the continuous production of 1,2-dichloroethane |
| JPH0723327B2 (en) * | 1985-12-09 | 1995-03-15 | 三井東圧化学株式会社 | Recovery method of heat of formation of 1,2-dichloroethane |
| DE4026282A1 (en) * | 1990-08-20 | 1992-02-27 | Hoechst Ag | METHOD AND DEVICE FOR THE PRODUCTION OF HIGH PURITY 1,2-DICHLORETHANE WITH HEAT RECOVERY |
| EP1411027A4 (en) | 2001-06-28 | 2009-07-29 | Sumitomo Chemical Co | Method of chlorine purification and process for producing 1,2-dichloroethane |
| FR2878171B1 (en) | 2004-11-19 | 2007-03-09 | Solvay | REACTOR AND METHOD FOR THE REACTION BETWEEN AT LEAST TWO GASES IN THE PRESENCE OF A LIQUID PHASE |
| DE102005044177A1 (en) * | 2005-09-15 | 2007-04-05 | Uhde Gmbh | Process and apparatus for utilizing the heat of condensation obtained in the purification of 1,2-dichloroethane |
| CN103360203B (en) * | 2013-07-03 | 2014-07-09 | 中国海洋石油总公司 | Method for producing dichloroethane by comprehensively utilizing refined dry gas |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| BE725636A (en) * | 1968-12-18 | 1969-06-18 | ||
| GB1422303A (en) * | 1973-06-11 | 1976-01-28 | Stauffer Chemical Co | Production of ethylene dichloride |
| DE2743975B1 (en) * | 1977-09-30 | 1979-03-01 | Bayer Ag | Process for the preparation of a practically vinyl chloride-free 1,2-dichloroethane |
| DE2935884A1 (en) * | 1979-09-05 | 1981-04-02 | Wacker-Chemie GmbH, 8000 München | METHOD FOR PRODUCING 1,2-DICHLORETHANE |
-
1981
- 1981-11-21 DE DE19813146246 patent/DE3146246A1/en not_active Withdrawn
-
1982
- 1982-11-02 CA CA000414663A patent/CA1221708A/en not_active Expired
- 1982-11-08 DE DE8282110276T patent/DE3260738D1/en not_active Expired
- 1982-11-08 EP EP82110276A patent/EP0080098B1/en not_active Expired
- 1982-11-12 ES ES517343A patent/ES517343A0/en active Granted
- 1982-11-18 JP JP57201230A patent/JPS5892626A/en active Granted
- 1982-11-19 BR BR8206726A patent/BR8206726A/en unknown
- 1982-11-19 MX MX195261A patent/MX161860A/en unknown
- 1982-11-19 SU SU823512805A patent/SU1480758A3/en active
- 1982-11-19 HU HU823737A patent/HU191194B/en unknown
- 1982-11-19 AU AU90749/82A patent/AU564581B2/en not_active Ceased
- 1982-11-19 AR AR291356A patent/AR231831A1/en active
- 1982-11-19 NO NO823884A patent/NO155575C/en unknown
- 1982-11-19 DD DD82245051A patent/DD206775A5/en not_active IP Right Cessation
- 1982-11-19 ZA ZA828536A patent/ZA828536B/en unknown
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7504077B2 (en) * | 1999-03-12 | 2009-03-17 | Uhde Gmbh | Method of producing ethylene (di) chloride (EDC) |
Also Published As
| Publication number | Publication date |
|---|---|
| AR231831A1 (en) | 1985-03-29 |
| NO823884L (en) | 1983-05-24 |
| BR8206726A (en) | 1983-10-04 |
| ES8307692A1 (en) | 1983-08-01 |
| EP0080098A1 (en) | 1983-06-01 |
| AU9074982A (en) | 1983-05-26 |
| DE3260738D1 (en) | 1984-10-18 |
| MX161860A (en) | 1991-01-30 |
| ZA828536B (en) | 1983-10-26 |
| DD206775A5 (en) | 1984-02-08 |
| JPS5892626A (en) | 1983-06-02 |
| DE3146246A1 (en) | 1983-05-26 |
| JPH0235729B2 (en) | 1990-08-13 |
| SU1480758A3 (en) | 1989-05-15 |
| AU564581B2 (en) | 1987-08-20 |
| HU191194B (en) | 1987-01-28 |
| NO155575B (en) | 1987-01-12 |
| EP0080098B1 (en) | 1984-09-12 |
| NO155575C (en) | 1987-04-22 |
| ES517343A0 (en) | 1983-08-01 |
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