DE1219915B - Process for the chlorination of benzene, monochlorobenzene and their mixtures - Google Patents

Description

FEDERAL REPUBLIC OF GERMANY

GERMAN

PATENT OFFICE

EDITORIAL

Int. CL:

C07c

German class: 12 ο -2/01

Number; 1219 915

File number: S 63726IV b / 12 ο

Filing date: July 2, 1959

Opening day: June 30, 1966

It is known that the direct chlorination of benzene with chlorine gas leads to a mixture of monochlorobenzene, o-, p- and m-dichlorobenzene and polychlorobenzenes (Trichlorobenzenes and higher chlorinated derivatives). The proportions of these various compounds are different depending on the working conditions, in particular on the ratio used from chlorine to benzene, from the chlorine passage rate, the temperature and the catalyst.

B ο u r i ο η (Ann. Chimic, 14, pp. 215 to 231 [1920]) identified the most favorable conditions for the production of monochlorobenzene with a low Amount of more strongly chlorinated derivatives, while M c M u 11 ί η (Chem. Ing. Progress, 44, No. 3, p. 183 [1948]) the distribution of the various compounds in continuous and discontinuous operation compared to each other.

Further publications deal in particular with the conditions for using certain catalysts. For example, Wiegandt and L a η d ο s (Ind. Engng. Chem., 43, p. 2167 [1951]) for various catalysts, the influence of their concentration, the temperature and the degree of chlorination on the proportion of p-dichlorobenzene obtained. This work highlighted the "self-inhibition" effect of o-dichlorobenzene and the influence of polar compounds, like anhydrous acetic acid, trichloroacetic acid, ethyl sulfate, but the writers got it high molar ratios of para to ortho compound only by increasing the degree of chlorination above 2.2 molecules of chlorine per molecule of benzene, with a significant amount of more chlorinated derivatives being the have little use, be educated.

US Pat. No. 1,946,040 (1931) describes a process for the chlorination of various organic derivatives in the presence of a catalyst consisting of sulfur and antimony trichloride, optionally with the addition of known catalysts such as Fe, PQ _{6 , AsCl 3} and pieces of lead. The weight ratio of p-dichlorobenzene to the total amount of o-chlorobenzene and more strongly chlorinated products reached 4.75 when the chlorination of benzene was carried out at 20 to 25 ^° C. It is known, however, that p-dichlorobenzene is in benzene, monochlorobenzene and mixtures thereof at this temperature relatively sparingly soluble. To avoid technical difficulties as a result of the strong crystallization, the chlorinations are generally carried out at low temperature under mild conditions, ie the ratio of chlorine to benzene is kept low and a high proportion of monochlorobenzene is obtained. To ensure a process for the chlorination of benzene,
Monochlorobenzene and mixtures thereof

Applicant:

Societe d'Electro-Chimie, d'Electro-Metallurgie

et des Acieries Electriques d'Ugine, Paris

Representative:

Dr.-Ing. A. v. Kreisler, Dr.-Ing. K. Schönwald
and Dr.-Ing. Th. Meyer, patent attorneys,
Cologne 1, Deichmannhaus

Named as inventor:

Jean Guerin, Jarrie, Isere (France)

Claimed priority:

France of July 3, 1958 (769 392)

significant production of p-dichlorobenzene must be used here very large apparatus, and the amounts of monochlorobenzene formed at the same time are very high.

Other catalysts have also been used. This is what it says in French patent specification 641102 (1927) that by introducing a halogen into benzene in contact with sulfuric acid an at least 80% monochlorobenzene-containing mixture is formed under conditions under which sulfonation is avoided.

In view of the difficulties and disadvantages of the various known processes for chlorination of benzene derivatives, the inventor re-studied the problem. The aim was without any noteworthy Formation of polysubstituted derivatives, both a reaction mixture in which almost the entire derivative to be chlorinated is converted into the disubstituted derivative or the disubstituted fraction contains a very high proportion of the p-derivative, as well as less strongly chlorinated mixtures, which are also distinguished by a high proportion of p-derivative in the disubstituted fraction. In the special case of the chlorination of benzene, the object of the invention is without significant formation of polychlorobenzene to produce raw mixtures, which are characterized by a high proportion of p-dichlorobenzene in the dichlorobenzene fraction, and their degree of chlorination up to almost complete conversion can be increased in dichlorobenzenes.

609 587/452

3 4

The investigations made it possible to establish that the orientation catalyst was being carried out. the

that on the one hand makes the known Chlorierungskatalysa- presence of the orientation catalyst

gate the binding of chlorine to the cyclic aroma- that is, regardless of the type and activity of the

table derivatives to different degrees of chlorination catalyst noticeable. It also acts equip and the use of active catalysts 5. the orientation catalyst often synergistically 'with

is required when large amounts of chlorine from one of the chlorination catalyst, i.e., it increases the

to be chlorinated starting material added reactivity of the latter and enables a

should, and that on the other hand these catalysts are not more quantitative chlorine uptake by the chlorinated

are capable of binding the chlorine in the desired rende product.

To direct dimensions so that; a certain disubstituted io to carry out the method according to Derivative is formed. However, most known chlorines are suitable for the investigation also found that the control of the chlorination catalysts, especially the usual metal bond in order to achieve a certain disub- or metalloidchloride and sulfide, the named substituted derivative by jointly using chlorides with attached or bound sulfur a chlorination catalyst and certain chemical 15 and the chlorosulfides. However, the simultaneous Connections is possible. Achievement of high chlorination yields, a high one

The invention relates to a process for conversion to the disubstituted derivative and a

Chlorination of benzene, monochlorobenzene and their high proportion of the p-compound in the disubstituted

Mixing in liquid phase with gaseous chlorine fraction by using very active chlorination

in the presence of known chlorination catalysts 20 catalysts favored, for. B. with antimony sulfide,

with preferential formation of p-dichlorobenzene, antimony chloride and antimony chlorosulfides in such

which is characterized in that the amounts that an absolutely complete implementation of the

Reaction in the presence of 3 to 40 percent by weight of chlorine with the starting material to be chlorinated

cent, based on the starting material to be chlorinated,

makes one of the following mixtures: 25 The chlorination catalyst can be added to the usual

λ in u- λιλγ * ■ u; '· ..Τ. 1 ii ·· manner in the starting material to be chlorinated

a) 30 to 40 weight percent benzenesulfonic, _{are alternates this beautiful but] ows} ^ _{cht from? there} / _a

50 to 60 percent by weight sulfuric acid, part of this catalyst during the chlorination in

5 to 15 percent by weight of water pass over the aqueous phase or beforehand into this

or 30 can be introduced. The chlorination catalyst

, ... ,,,. "_.,. _,,, "Will be used in order to achieve the desired activity

b) 10 to 50 percent by weight of a toluenesulfonic acid _required usual amount used.

or a mixture. _The method according to the invention requires

several toluene sulfone intimate contact of the starting material to be chlorinated

acidic, ₃₅ ^^ _the orientation catalyst. To this end

40 to 70 weight percent sulfuric acid _wn, -d he _unt vigorous stirring worked, whereby

5 to 15 percent by weight of water at least part of the aqueous phase in the too

_{o he} d chlorinating starting material is evenly distributed.

>. ",. .._ ... ■. _ ,,,,,, ". After reaching the desired chlorination

c) 20 to 40 percent by weight of p-chlorobenzenesulfone- _{4 <J degrees, the} reaction mixture is allowed to stand.

^acidic 'It usually separates into two liquid

50 to 75 percent by weight sulfuric acid, phases. The organic phase is separated and in

5 to 10 percent by weight of water is treated in a known manner to make the ingredients

or to separate and purify. The other phase

_1N _, .. "," ... ■ T ^, ". i- 45 which contains the orientation catalyst can be

d) 5 to 15 weight percent dodecylbenzenesulfonic _give appropriate, their replacement by fresh

acidic starting materials for the next chlorination batch

15 to 40 percent by weight benzenesulfonic acid,. can be reused.

40 to 70 percent by weight sulfuric acid, the process can be carried out within a wide

5 to 10 percent by weight water, 5 ° temperature range can be carried out. This is how it is

..-, .-. possible to use different phases of chlorination

whereby man.die mixtures mentioned to be carried out by strongly varying temperatures.

Stir intimately with the starting material to be chlorinated Except for the explanations given above

mixed. .-..'- ... - the process has obvious advantages

Like the one above. Composition of the mixtures used as 55 of the invention: Orientation catalysts on the one hand improves the presence of the orientation a practically quanti-sulfuric acids and, certain sulfonic acids. The tative value, on the other hand, it reduces the amount of constituents of these. Mixtures can be in any of the more strongly known chlorinated derivatives formed during chlorination for the preparation of these substances ...
be obtained .. ..,:. ■ - As already mentioned, the chlorination leads to a

The presence of the orientation catalyst has a crude chlorination mixture, which is next to a tailor The result is that you get used to doing the chlorinated amount of benzene and monochlorobenzene according to the invention obtained ratio of 65 borrowed o-, p- and m-dichlorobenzene, trichlorobenzenes and Amount of p-V compound to the amount of o-compound also contains higher chlorinated derivatives. The quantities is much higher than when the various compounds are different in chlorination otherwise the same conditions in the absence of the dependence on the working conditions, in particular

5 6

those of the ratio of chlorine to benzene, of which the chlorine was. The chlorine supply was interrupted when

passage speed, temperature and taking into account the developed by the

used catalyst. Hydrochloric acid entrained benzene about 95% of the chlorine

The process according to the invention enables an amount corresponding to the complete conversion to dichloro to achieve a high degree of chlorination of 5 benzene was introduced.
Benzene, monochlorobenzene and their mixtures. After stopping the supply of chlorine was heated to this is to avoid a small residual amount of benzene or ground to about 50 ⁰ C to the presence of monochlorobenzene, a high proportion of p-dichloro- crystallized p-dichlorobenzene, and benzene in the fraction of Dichlorobenzenes and one let sit down. The chlorination mixture resulted in a very small proportion of more highly chlorinated derivatives in terms of removal of various impurities. In order to achieve good reaction conditions of the antimony chloride, with technical salt, the amounts of the chlorination catalyst acid, diluted to a third of their concentration, are expediently chosen as follows: With Sb ₂ S ₃ between, washed, then neutralized, dried 0.1 and 0, 8%, for FeCl ₃ between 0.05 and 0.5%, and distilled.

with a mixture of S and SbCl ₃ between 0.1 and 15 The average compositions of the in

1% SbCl ₃ and 0.1 to 0.5% S, based on the chlorination mixtures obtained in several experiments

chlorinating raw material. Those already mentioned were as follows:
Numbers for the relative amounts of the two phases

apply to the chlorination of benzene. The tempera- Remaining benzene <0.05%

Doors are between 15 and 60 ° C. This temperature is 20 monochlorobenzene about 5%

temperature range enables the chlorination of dichlorobenzene to be about 95 "/

15 as long perform to 20 ° C until the chlorination Uicluorbenzoi about _95/0

is so high that a crystallization of the higher chlorinated derivatives <0.2%

p-Dichlorobenzene and the associated tech- ratio Para to Ortho 5 to 6.5: 1

niche difficulties are to be feared, to which 25

the temperature increased to 50 ° C or even 60 ° C. The proportion of p-dichlorobenzene in the dichloro

will. At 20 ⁰ C the technical difficulties occur benzene fraction was 86% · It should be noted that about

usually on when four fifths of the chlorine, the 5% of the benzene in the form of fumes by the free

the complete conversion of the benzene into di-become hydrochloric acid were carried away. This

chlorobenzene, have been introduced. However, at 30 benzene could be recovered

the chlorination of benzene according to the invention The orientation catalyst used (mixture

can at high rates of chlorine supply of sulfuric acid and benzenesulfonic acid) was like

to be worked. For example, the following can be produced in 12 hours: In 700 g of dry benzene

to the full Umwand- for batch were at 5O ⁰ C with vigorous stirring 1200 g

conversion of benzene in dichlorobenzene corresponding 35 sulfuric acid of very high purity (94% H ₂ SO ₄ )

Introduce the amount of chlorine without affecting the chlorine content of the pouring. The addition was gradual within

hydrochloric acid released exceeds 10. about 1.5 hours. During this time the

In the following, exemplary embodiments of the temperature are increased to 58 to 60 ° C. After cooling down

Fahrens according to the invention in the application to 40 ° C was allowed to settle. The lower layer

brought the chlorination of benzene. . 40 (59% H ₂ SO ₄ , 33% C ₆ H ₅ SO ₃ H, and 8% H ₂ O)

removed and used as an orientation catalyst

Example 1 used the manner described. The same

Mixture would also have made of sulfuric acids with others

Several experiments were carried out as follows: Initial concentration can be established.
In 2 kg of benzene, which had been dried by azeotropic distillation 45 To demonstrate the effectiveness of the orientation, 5 g of antimony trichloride catalyst were dissolved in comparison tests according to the (pure) and then 2 g of sulfur. The solution was given to known methods without benzenesulphonic acid (ie in a glass flask provided with a stirrer and a heating or cooling pre-without orientation catalyst) with the same direction. Chlorine in chlorination catalyst at about the same temperatures in an amount of 240 g / h was introduced for 45 minutes in the 50 temperatures and at the same or lower solution. Thereafter, 350 g of a chlorine feed rate was carried out. A mixture of sulfuric acid and benzenesulfonic acid was chlorinated to the same degree, ie up to the introduction of 95% of the amount of chlorine that was added _{with 59% H 2} SO ₄ , 33% C ₆ H ₅ · SO _{3 H and 8% water.} Stirring was continued in order to ensure that the intimate contact between the two benzene contained in the starting mixture was continuously converted into dichlorobenzene. Ensure liquid phases. Having achieved this, the following results were obtained:
was, the amount of chlorine was increased to 355 g / h and
the cooling adjusted so that 20 ⁰ C was reached. Chlorination mixture:

The mentioned chlorine supply was maintained, monochlorobenzene 7.5%

up to about two thirds of the amount of chlorine that the full 60

constant conversion of benzene into dichlorobenzene dichlorobenzenes 92.2 / ₀

was introduced without the trichlorobenzenes released 0.3%

Hydrochloric acid more than 0.001 percent by weight of chlorine Chlorine content in the gases according to the

contained. After reducing the chlorine supply to chlorination (based on hydrochloric acid) 2 batches

The temperature was allowed to rise to 240 g / h after 65 percent by weight Crystals of p-dichlorobenzene began to appear.

This occurred when, during the chlorination at 20 ° C., the fraction of dichlorobenzenes contained the fraction

four fifths of the chlorine required introduced the p-dichlorobenzene at about 75%.

Example 2

The procedure was as in Example 1, but 0.25% Sb ₂ S ₃ in powder form was brought into suspension instead of S + SbCl _3.

Below are the results of experiments carried out according to the invention as well as those known Procedures carried out were juxtaposed.

Chlorination mixture
Monochlorobenzene ...

Dichlorobenzene

Higher chlorinated
Derivatives {mainly trichlorobenzenes)

Cl in the vacated
HCl

Proportion of p-dichlorobenzene in the dichlorobenzene fraction

Procedure according to
the invention

8.4%
91.6%

<0.001 Ge.
weight percent

84%

Known
procedure

7.9%
91.7%

0.4%
1%

77%

SbCl ₃ and 3 cm ^{3 of} sulfur dichloride dissolved. After the chlorination reaction had started, 350 g of benzenesulfonic acid of the composition mentioned in Example 1 were poured in and the process continued in the manner described there. The crude chlorination mixture contained

Monochlorobenzene 5.5%

Dichlorobenzenes 94.3%

ίο trichlorobenzenes 0.2%

In the dichlorobenzenes fraction, the proportion of p-dichlorobenzene was 85%

Example 6

In this experiment sulfur was introduced in the form of a solution in carbon disulfide.

_{5 g of SbCl 3 were} dissolved in 2 kg of dry benzene. Then 5 cm ^{3 of} a warm (40 ° C.) saturated solution of sulfur in carbon disulfide were poured in. After triggering the chlorination reaction and adding 350 g of benzenesulfonic acid of the composition already mentioned, the procedure was continued as in Example 1.

In the dichlorobenzenes fraction, the proportion of p-dichlorobenzene was 84.5%.

Example 3

Ferric chloride was used as the chlorination catalyst. Using the orientation catalyst according to example 1 the following results could be achieved:

Chlorination mixture:

Monochlorobenzene 8.6%

Dichlorobenzene 91.3%

Higher chlorinated derivatives ........ 0.1%

Proportion of p-dichlorobenzene in the

Dichlorobenzene fraction 82%

Amount of the entrained by HCl
Chlorine. · .... <0.001 percent by weight

Example4

To form the orientation catalyst in contact with the starting material to be chlorinated, 5 g of SbCl ₃ and 2 g of sulfur were dissolved in 2 kg of dry benzene. As in Example 1, chlorine was passed into the solution in an amount of 240 g / h for 45 minutes. After adding 300 g of 96% sulfuric acid, the mass was stirred at 55 ° C. for 15 minutes. The amount of chlorine was increased to 355 g / h and the mass was allowed to cool to 20.degree. Then, as in Example 1, the procedure was continued. The results obtained were within the limits stated in this example.

Similar results were obtained when using 20% oleum instead of 96% sulfuric acid It went out, but the oleum was poured in slowly after the temperature of the mass Had reached 20 ° C (instead of 55 ° C). After this partial sulfonation was continued as before.

Example5.

_{SbCl 3} + SCl _{2 was} used as the chlorination catalyst. There were 5 g in 2 kg of dry benzene

Example 7

The orientation catalyst was prepared from an acid mixture of 60% sulfuric acid, 37% p-chlorobenzenesulfonic acid and 3% water, diluted with 5% ice. During the chlorination, 350 g of this acid were poured into 2 kg of benzene containing 5 g of SbCl ₃ and 2 g of sulfur. After chlorination, the mixture had the following composition:

Monochlorobenzene 10%

Dichlorobenzenes 90%

Part of the p-dichlorobenzene in the

Dichlorobenzenes fraction 82%

Example 8

A mixture of 50 percent by volume of chlorine and nitrogen was introduced into 2.2 kg of dry benzene, catalyzed by 6 g of SbCl _{3 and 2.5 g of sulfur.} After the chlorination reaction had started, 350 g of crude benzenesulfonic acid, prepared in the manner described in Example 1, were poured into the mixture. After completion of the chlorination, the reaction mixture had the following composition:

Monochlorobenzene 7.0%

Dichlorobenzenes 93.0%

In the dichlorobenzenes fraction, the proportion of p-dichlorobenzene was 83%

Example 9

A mixture of 50 percent by volume of chlorine and HCl was introduced into 2.2 kg of dry benzene, which _{contained 6 g of SbCl 3 and 2.5 g of sulfur as a catalyst.} After the chlorination reaction had started and 350 g of benzenesulfonic acid mixture had been poured in (see Example 1), the procedure was continued as in Example 1.

In the dichlorobenzenes fraction was the. proportion of of p-dichlorobenzene 84.5%

Example 10

5 g of antimony trichloride and 3 g of sulfur were dissolved in 2.1 kg of dry benzene. After 45 minutes Chlorine had been passed in, were 350 g of a mixture of benzene and dodecylbenzenesulfonic acid poured in.

On the one hand, benzene was sulfonated to form the orienting phase. For this purpose, 1200 g of sulfuric acid (95%) ^m 700 g of benzene were cast. After stirring for 1.5 hours at 6O ⁰ C was allowed to settle. On the other hand, dodecylbenzene, commonly referred to as alkylate and used as a starting material for alkylarylsulfonates, has been sulfonated. For this purpose, 95% ig was poured ^e sulfuric acid in an amount of 500 g in 100 g of alkylate and the mixture was stirred for 1.5 hours at 6O ⁰ C.

Then 1400 g of crude benzenesulfonic acid and 600 g of dodecylbenzenesulfonic acid (raw, not filtered) mixed. The mixture contained

60.8V ₀ H ₂ SO ₄
25.2% C ₆ H ₅ SO ₃ H

6.65% C ₆ H ₄

SO ₃ H

15th

20th

7.35% water

Were after 350 g of this mixture in the chlorine to be chlorinated cast, the supply of chlorine to 355 g / h increases, and set the cooling of the chlorination mixture to 20 ⁰ C.

The experiment completed in the manner described in Example 1 gave a chlorination broth the following composition:

Monochlorobenzene 12.8%

Dichlorobenzene ·; 87.2%

The proportion of p-dichlorobenzene in the fraction of Dichlorobenzene was 86.5%

Claims (4)

Patent claims: 1. Process for the chlorination of benzene, monochlorobenzene and their mixtures in liquid Phase with gaseous chlorine in the presence of known chlorination catalysts, preferably with Formation of p-dichlorobenzene, thereby ίο characterized in that the reaction is carried out in the presence of 3 to 40 percent by weight, based on the starting material to be chlorinated, makes one of the following mixtures: a) 30 to 40 percent by weight benzenesulfonic acid,
50 to 60 percent by weight sulfuric acid, 5 to 15 percent by weight water
or b) 10 to 50 percent by weight of a toluenesulfonic acid or a mixture of several
Toluenesulfonic acids,
40 to 70 percent by weight sulfuric acid, 5 to 15 percent by weight water
or c) 20 to 40 percent by weight of p-chlorobenzenesulfonone acid, 50 to 75 percent by weight sulfuric acid,
5 to 10 percent by weight water
or d) 5 to 15 percent by weight of dodecylbenzenesulfon acid, 15 to 40 percent by weight benzenesulfonic acid,
40 to 70 percent by weight sulfuric acid,
5 to 10 percent by weight water, the mixtures mentioned being mixed with the starting material to be chlorinated by vigorous stirring intimately mixed. 2. The method according to claim 1, characterized in that the chlorination of benzene initially at 15 to 20 ° C and, as soon as p-dichlorobenzene begins to crystallize, the Temperature increases up to 60 ° C. 3. The method according to claim 1 and 2, characterized in that the chlorine to be chlorinated Liquid at high speed, on the order of 200 g per hour / kg chlorinating starting material, feeds. 4. The method according to claim 1 to 3, characterized in that one in the work-up the aqueous phase obtained from the reaction mixture, if appropriate after adjusting to its initial composition, used for a new chlorination. KQTMCO fi Cd