DD208604A5 - CATALYST MIXTURE AND METHOD FOR THE PRODUCTION OF 1,2-DICHLORETHANE - Google Patents

Abstract

The invention relates to a catalyst mixture consisting of anhydrous ferric chloride and a further mixture component, for the preparation of 1,2-dichloroethane by reaction of ethylene with chlorine in a solvent at normal or excess pressure. The aim of the invention is to restrict corrosion and by-product formation and to make the process more economical. It is the object of the invention to provide a novel catalyst mixture and also a 1,2-dichloroethane preparation process using this mixture. The mixture is characterized in that the further mixture component is an amount of a nitrogen base which is approximately equivalent in relation to the amount of iron (III) chloride or a salt of this base.

Description

24 5 6 14 4 1.3.1983

AP B 01 J / 245 614 61 726 12

Catalyst mixture and process for the preparation of 1,2-dichloroethane

Field of application of the invention

The invention relates to a Katalysatorgeraisoh and a manufacturing method of 1,2-dichloroethane by means of this mixture. 1,2-Dichloroethane has various uses, but most of all it is needed for the production of vinyl chloride.

Well-known technical solutions

The production of. 1,2-Dichloroethane is known by the reaction of ethylene with chlorine in 1,2-dichloroanethane as the solvent and the reaction medium, and its principal byproduct in this reaction is 1,2-eichloroethane by the substitution of dichloroethane. In order to suppress this substitution reaction, the catalysts used are, in addition to the chlorides, the elements. Group of the Periodic Table, especially water-iron chloride, in part with the simultaneous generation of oxygen, since ferric chloride is readily available and inexpensive ·

The crude, katalyaatorhaltige dichloroethane is generally withdrawn from the reaction vessel and treated to remove the catalyst and d.ss contained in the crude hydrogen chloride with V / asser or aqueous alkali solutions and then worked up by distillation by known methods.

The use of PeCl 2 as a catalyst in the addition chlorination of ethylene has certain disadvantages. Thus, in the presence of water, PeClI acts corrosively against the materials of reactors. columns

2456U 4 -

03/01/1983

AP B 01 J / 245 614

61 726 12

or heat exchangers as far as they come into contact with the catalyst. »The normally used technical grade chlorine always contains traces of moisture and hydrogen chloride from unwanted side reactions.

If the thermal energy released in the chlorination of ethylene is to be utilized, the reaction must be carried out at temperatures above the boiling point of dichloroethane at normal pressure. Since the corrosion rate increases considerably with increasing temperature, it is essential to equip the apparatuses for the chlorination reaction with corrosion-resistant substances, which impairs the economic efficiency of the process used.

Object of the invention

It is an object of the invention to substantially reduce corrosion and reduce by-product formation.

Essence of the invention

The invention is based on the task of providing a new catalyst mixture and a production process for 1,2-dichloroethane. "

It has now been found that the corrosion caused by FeCl 3 as a catalyst in the production of 1,2-dichloroethane can be considerably reduced in non-corrosion-resistant reactors by adding certain additives to the FeCl 2 catalyst. In addition, it has been determined

crnf rli'o TXo-.

24 56 U 4

03/01/1983

AP B 01 J / 245 61 726 12

benproduktbildung, which is thereby reduced impact.

The invention thus relates to a Katalysatorgemiseh consisting of anhydrous ferric chloride and a further mixture component, for the preparation of 1,2-dichloroethane by reaction of ethylene with chlorine in a solvent at normal or elevated pressure, which is characterized in that the further mixture component is an approximately equivalent amount of a nitrogen base or a salt of this base in relation to the amount of ferric chloride.

The nitrogen base may be NH 1, a primary, secondary or tertiary alkyl, aralkyl, aryl or alicyclic amine or a polyamine. The salt of the nitrogenous base is preferably a halogen salt, for example ammonium chloride.

Another object of the invention is a process for the preparation of 1,2-dichloroethane using the catalyst mixture according to the invention.

U 4

The process of the invention for producing 1,2-dichloroethane by reacting ethylene with chlorine in a solvent in the presence of a catalyst mixture of anhydrous ferric chloride and another mixture component and optionally an inhibitor to prevent byproduct formation at a temperature of about 20 to 200 ⁰ C and normal or excess pressure and separating the 1, 2-dichloroethane from. the chlorination mixture by distillation is characterized in that

a) the further mixture component is a nitrogen base or a salt of this base,

b) the further mixture component is present in an approximately equivalent amount to the ferric chloride amount in the mixture and _vj; , ..., -

c) the concentration of ferric chloride is 0.005 to about 0.5% by weight, based on the amount of the solvent.

As already mentioned in the explanation of the catalyst mixture, the nitrogen may be NH.sup.-, a primary, secondary or tertiary alkyl, aralkyl, aryl or alicyclic amine or a polyamine. The salt of the nitrogen base is preferably a halogen salt, especially ammonium chloride.

According to a preferred embodiment of the method of the invention, the solvent used is 1,2-dichloroethane and as inhibitor oxygen.

2456U 4

More specifically, as regards the procedure of the invention, the following should be noted:

The catalyst according to the invention is generally dissolved or suspended in the solvent introduced in the reactor. However, it can also be prepared outside the reaction solution by suspending the anhydrous FeCl 2 together with the further catalyst component in, for example, 1,2-dichloroethah and introducing the suspension into the reactor. It is also possible to charge the solvent introduced in the reactor with anhydrous FeCl 2, and NH 2, or an amine. In the subsequent reaction then 'sufficient hydrogen chloride is formed to form the corresponding ammonium salt.

The catalyst according to the invention is considered to be technically advanced, since it suppresses to a considerable extent the corrosion which occurs in the known processes for the preparation of 1,2-dichloroethane and adversely affects corrosion when using non-corrosion-resistant metallic reactors. Furthermore, it was found that with the exception of small amounts of the first substitution product 1,1,2-trichloroethane and a correspondingly small amount of hydrogen chloride under the process conditions of the invention as good as no further by-products are formed. The reaction solution remains bright even when the reaction is prolonged, if the additives according to the invention are present in the reaction solution in an approximately equivalent amount in the iron chloride present. An optionally already darkly colored in the course of the reaction reaction mixture brightens in the extent of addition, the compounds mentioned in the further course of reaction again. Finally, it should be noted that in the process of the invention the conversion is nearly quantitative with high space / time yield.

2456U 4

The process of the invention can be carried out, for example, in the loop reactor described in DE-OS 24 27 045 or in any other reactor suitable for carrying out the process.

The object of the invention will be explained in more detail with reference to the following examples:

Example 1> ν

In a loop reactor with a capacity of about 2 1, 2.0 kg of 1,2-dichloroethane and 4 g of anhydrous ferric chloride were submitted. In this mixture, 0.42 g of ammonia in the form of a 0.67 wt% solution in dichloroethane at 30-40 C introduced. The rising part of the reactor loop contained a packed bed. Below the Füllschichtschich | vbefanden inlet pipes in the reactor for ethylene, ßhlor and air, through each about 60 l / h of chlorine and Ethyls% - sowi ^! e 15 l / h of air were fed. The reactor liquid was circulated in the reactor system according to the mammoth pump principle and the catalyst mixture was suspended uniformly in the liquid phase. During the reaction, a reaction temperature of about 77 ⁰ C in a turned Raaktionsgemisch. The concentration of the catalyst mixture dissolved in the reactor liquid, bestipnt as FeCl ₅₁ was 0.13% after several days.

In a arranged above the reactor water cooler, the withdrawn from the reactor dichloroethane vapors were condensed and then diverted one of the produced amount corresponding part of the condensate by means of a condensate divider and removed, while excess

24 56 U 4

Condensate was returned to the reaction zone. By means of a cold trap, a further Dichlqrethan portion of the predominantly consisting of inert gases exhaust gas was deposited. After a running time of the continuous process of several days, the catalyst mixture had largely dissolved in the reactor liquid, and a colorimetric determination of the Fe content in the reactor liquid gave a PeÖl ^ ö content of about 0.13% by weight. The hourly amount of 1,2-dichloroethane was 262 g. The procedure was carried out continuously for 14 days.

The analysis of the product A or the reactor liquid B in the condenser after completion of the reaction gave the following values:

Product A (weight) Product B (% by weight) C ₂ H ₅ Cl 1,2-EDC 1,1,2-ETC HCl Other <0.002 99.94 0.04 <0.001 0.01 <£ 0.002 99.82 0.14 0.04

EDC = 1,2-dichloroethane ETC = 1,1,2-trichloroethane

Example 2

The procedure was analogous to Example 1, except that 50 ml of 1,2-dichloroethane containing 0.4-1,1,2,2-trichloroethane by means of a dropping funnel were additionally added to the reaction mixture which had been circulated in the reactor.

2456U

were dripping. The hourly amount of 1,2-dichloroethane was 326 g. The test duration was 8 days, and the analysis of the product A or reactor liquid B in the condenser after the reaction had ended gave the following values:

Product A (weight 6) Product B (% by weight) C ₂ H ₅ Cl <; 0,002 <. 0,002 1,2-EDC 99.87 99.61 1,1,2-ETC 0.10 0.34 HCl <0.001 - other 0.03 0.05

Example 3

The procedure was analogous to Example 1, except that the concentration of FeCl, in the reaction mixture and the molar ratio of FeCl, were varied to the ammonia. The extent of the changes made and how these changes affected the levels of 1,1,2-ETC and HCl in the condenser product are shown in the table below.

concentration molar ratio Gew # 1,1,2- wt% FeCl, (wt%) FeCl ₃ ZNH ₃ ETC HCl 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

2456 U 4

The hourly amount of 1, 2-dic.hio.rethan was for the experiment with the FeCl ^ -Kaftzentration of Q, 32% by weight 260 g and the duration of the experiment 19 days. The analysis of the product A or the reactor liquid B in the condenser after completion of the reaction gave the following values:

Product A (weight) Product B (% by weight) C ₂ H ₅ Cl ^ 0,002 <Q, 002 1.2 EDC 99.93 99.78 1,1,2-ETC 0.06 0.19 HCl 0.001 other 0.01 o, Q3-. ': ·.; ·.:. = ·; . ·;;

Example 4

The procedure was analogous to Example 1, but using 1> 35 kg of 1,2-dichloroethane and, instead of ammonia, 1.3 g of trimethylamine, dissolved in 30 ml of 1,2-dichloroethane, were added to the reaction solution. The hourly amount of 1,2-dichloroethane was 276 g and the duration of the test 6 days. Furthermore, the FeCl 2 content determined colorimetrically in the solution averaged 0.13% by weight.

Analysis of the product A in the condenser after completion of the reaction gave the following values:

Product A (Gewtf) C ₂ H ₅ Cl 1.2 EDC 1.1.2 ETC HCl 99.86 0.13 0.01

2456U 4

Example 5

The procedure was analogous to Example 4, except that 1.7 g of FeCl, and 0.65 g of diaminoethane were added to the reaction solution as a catalyst. The colorimetrically determined content of FeCl 2 in the solution averaged 0.07% by weight. Hourly 268 g of dichloroethane were obtained and the experiment lasted for 3 days.

The analysis of the product A obtained in the condenser gave the following values:

Product A (wt%) C ₂ H ₅ Cl - 1.2 EDC 99.13 1,1,2 ETC 0.85 HCl 0.02 other 0.01

Example 6

The procedure was analogous to Example 1, except that 1.5 kg of 1,2-dichloroethane were used and the amount of catalyst was 3.3 g FeCl, and 3.0 g of triethanolamine. The FeCl 2 content determined colorimetrically in the reaction solution averaged 0.25 wt. Hourly 268 g of dichloroethane were obtained and the trial lasted for 6 days.

The analysis of the product A obtained in the condenser gave the following values:

245614

Product A (wt%) C ₂ HCl <0.002 1.2 EDC 99.65 1,1,2 ETC 0.33 HCl 0,007 other 0.01

Example 7

a) In a 2 1 round bottom flask, which was equipped with stirrer, dropping funnel and reflux condenser, 2 kg of 1,2-dichloroethane were presented with 2.1 g of ferric chloride. The mixture was heated to boiling with stirring and then added dropwise 0.2 g of ammonia dissolved in 58 g of dichloroethane, so that the total amount of catalyst was 2.3 g. After the mixture had been boiled under reflux for a further 5 hours, a content of 0.11% by weight of FeCl 2 in the solution was determined colorimetrically.

b) The mixture of dichloroethane and catalyst was then introduced into the loop reactor described in Example 1 and then each introduced about 60 l / h of chlorine and ethylene together with about 5 l / h of air into the reactor. Hourly 273 g of dichloroethane were obtained and the experiment lasted 8 days.

The analysis of the product A obtained in the condenser gave the following values:

245614 4

Product A (weight) C ₂ H ₅ Cl <0.002 1,2-EDC 99.51 1,1,2-ETC 0.48 HCl 0,002 other 0.009

Example 8

a) The procedure was initially analogous to Example 7a), except that 1.5 kg of 1,2-dichloroethane were heated with 12 g of FeCl, with stirring to boiling. To the mixture was added dropwise a solution of 2.7 g of hydrogen chloride in 750 g of dichloroethane and then a solution of 1.26 g of NH 4 in 273 g of dichloroethane. The reaction mixture was filtered after cooling and the filter residue dried. There were obtained 14.4 g of dry catalyst.

b) For the preparation of 1,2-dichloroethane, 4 g of the catalyst prepared according to a) and 2 g of FeCl 2 were suspended in 2.7 kg of 1,2-dichloroethane and, after concentrating the mixture volume to about 2 liters, the mixture in the example 1 introduced loop reactor. Each hour, 60 l of chlorine and ethylene and 15 l of air were introduced into the loop reactor and the reaction was initiated under the reaction conditions mentioned in Example 1. There were obtained 266 g of 1,2-dichloro-ethane and the experiment lasted 6 days. The FeCl 2 content determined colorimetrically in the reaction solution was on average 0.15% by weight.

2456U A

The analysis of the product A or the reactor liquid B in the condenser after completion of the reaction gave the following values:

Product A (wt%) Product B (% by weight) C ₂ H ₅ Gl 1,2-EDC 1,1,2-ETC HCl Other 0.004 99.93 0.06 0.002 0.003 0.006 99.74 0.23 0.03

Example 9

In a reactor for the industrial production of 1,2-dichloroethane corrosion samples were used at 4 points of the reactor and the samples subjected to the process conditions according to the invention. At intervals of 20 days, the samples were removed from the reactor and determined by corrosion-related removal. When using the FeCl ^ / NH catalyst according to the invention and maintaining a

Reaction temperature of 100 - 110 C, the average corrosion rate for unalloyed steel was less than 0.05 mm per year. On the other hand, when the process was carried out in a known manner using only FeCl 2 as a catalyst, the average corrosion rate for unalloyed steel was 0.43 mm per year.

Claims (6)

6 5 6 1 4 4 1.3.1983 AP B 01 J / 245 61 726 12 invention claim 1. Catalyst mixture. »Consisting of anhydrous ferric chloride and a v / eiteren mixture component, for the preparation of 1,2-dichloroethane by reaction of ethylene with chlorine in a solvent at normal or" overpressure, characterized in that the further Mixture component is an approximately equivalent amount of a nitrogen base or a salt of this base with respect to the amount of Eiae III chloride. 2. Mixture according to item 1, characterized in that the nitrogen base is NEW, a primary, secondary or tertiary alkyl, aralkyl, aryl or an alicyclic amine or a polyamine. 3. Mixture according to item 1, characterized in that the salt of the nitrogen base is a halogen salt. 4. Mixture according to item 1, characterized in that the salt of the nitrogenous base is ammonium chloride. 5. A process for the preparation of 1,2-dichloroethane by reaction of ethylene with chlorine in a solvent in the presence of a catalyst mixture of v / fererfreien ferric chloride and a further mixture component and optionally an inhibitor to prevent by-product formation at a temperature of about 20 to 200 C and normal or positive pressure and separating the 1,2-dichloroethane from the chlorination mixture by distillation, characterized in that a) the v / eitere mixture component is a nitrogen base or a salt of this base, 2456U k - 03/01/1983 AP B 01 J / 245 61 726 12 b) the further mixture component is present in an approximately equivalent amount to the amount of iron-IlI chloride in the mixture and c) the concentration of ferric chloride is 0.005 to about 0.5% by weight, based on the amount of the solvent. « Process according to item 5, characterized in that the nitrogen base is NH -, a primary, secondary or tertiary alkyl, aralkyl, aryl or alicyclic amine or a polyamine. Method according to item 5, characterized in that the salt of the nitrogen base is an Ilalogen salt. 8, process according to item 5, characterized in that the salt of the nitrogen base is ammonium chloride. 9o method according to item 5-8, characterized in that the solvent is 1,2-dichloroethane. Oo method according to item 5-9, characterized in that the inhibitor is oxygen «