DE1193510B - Process for the preparation of bromine derivatives of diphenyl, diphenyl ether, diphenyl phenyl ether or di-, tri- or tetraphenyl methane with 4 or more bromine atoms per mol - Google Patents

Description

FEDERAL REPUBLIC OF GERMANY

GERMAN

PATENT OFFICE

EDITORIAL

Int. α .:

C 07c

German: 12 q-14/04

Number: 1193 510

File number: C 28110 IVb / 12 q

Filing date: October 6, 1962

Opening day: May 26, 1965

Several processes are already known or have been proposed for the preparation of bromine derivatives of aromatic compounds with several non-condensed benzene nuclei in the molecule, which contain four or more bromine atoms per molecule. For example, bromine derivatives of diphenyls with four or more bromine atoms per molecule can be obtained from corresponding bromine derivatives of benzidine _{by splitting off the NH 2 groups.} These bromine derivatives of benzidine are in turn obtained by brominating acetylated benzidine in glacial acetic acid. The direct bromination of diphenyl in organic solvents, such as carbon tetrachloride, leads only to the dibromo derivatives of diphenyl, even under the most severe reaction conditions, for example the use of heat or the addition of oleum.

In contrast, the pentabromo derivatives of diphenyl ether can be obtained much more easily. Around To produce products, diphenyl ether is in carbon tetrachloride as a solvent and in the presence brominated by iron as a catalyst at boiling point.

The direct bromination of diphenyl or diphenyl ether in solvents can be done Carry out this known process only in long reaction times and mostly only at the boiling point, if technically useful results are to be obtained.

Some progress in the preparation of bromine derivatives of aromatic compounds with several non-condensed benzene nuclei is achieved by a recent proposal. Diphenyl or diphenyl ethers can then be brominated in an inert solvent, preferably carbon tetrachloride, in the presence of known halogenation catalysts at temperatures of 10 to 50.degree. C., preferably 20 to 35.degree. It is essential here that, in addition to the bromine, chlorine is also passed into the reaction mixture, which oxidizes the hydrogen bromide formed during the bromination in the reaction vessel to free bromine. The large-scale implementation of the process has shown that this process has certain deficiencies. To achieve a sufficient yield and an industrially usable product, an excess of bromine of at least 20 percent by weight must be used. After the bromination has been carried out, this excess bromine must be converted by reducing agents into technically inferior compounds which cannot be returned to the process. Another disadvantage of this process is the large-scale formation of chlorobromomethanes, which occurs in the production of bromine derivatives of diphenyl, diphenyl ether,
Diphenylphenylether or di-, tri- or
Tetraphenylmethane with 4 and more
Bromine atoms per molecule

Applicant:

Chemical factory Kalk G. mb H.,
Cologne-Kalk, Kalker Hauptstr. 22nd

Named as Erfipder:

Dr. Herbert Jenkner, Cologne-Deutz

and carbon tetrabromide by re-halogenation of the carbon tetrachloride used as a solvent. Not to mention the bromine losses caused by this re-halogenation, the chlorobromomethane and carbon tetrabromide can only be removed with great difficulty and under great technical conditions Expenditure of the bromine derivatives of aromatic compounds with several non-condensed benzene nuclei separate in the molecule. On the other hand, the technical application, such as flame retardancy of polyolefins, the mostly odorless and physiologically harmless bromine derivatives of aromatic compounds with several non-condensed benzene nuclei in the molecule at least severely restricted if these bromine derivatives are those that smell unpleasant and have a poisonous effect Contain chlorobromomethane as impurities. Besides, these impurities also aggravate nor the otherwise low tendency of bromine derivatives to sweat out of plastics.

It has now been found that the disadvantages outlined can be avoided if one is involved in the production of bromo derivatives of diphenyl, diphenyl ether, diphenylphenyl ether or di-, tri- or Tetraphenylmethane with four or more bromine atoms per molecule by reacting it in a solvent at least partially dissolved diphenyls, diphenyl ethers, diphenylphenyl ethers or di-, tri- or tetraphenylmethane in the presence of small amounts of a halogenation catalyst and optionally Water at room temperature or at an elevated temperature, optionally with the addition of chlorine

509 577/417

3 4

Bromine the bromination in the presence of olefin dibro - only a rapid oxidation of the bromide, especially ethylene or propylene dibromide, as a mation of hydrogen bromide to free Solvent carried out and after termination of the bromine, the again on the brominating aromatic 'Bromination in the reaction mixture olefins, special compound acts, but it also activates ders ethylene or propylene, in such an amount 5 the course of the bromination evidently through formation

initiates that they exist in the reaction mixture of chlorine-bromine compounds or by atomic

where an excess of bromine is at least equimolar. Bromine, which is produced by the oxidation of hydrogen bromide

In addition, the preferred solvent can be formed.

applied ethylene or propylene dibromide also. After completion of the bromination, the re-butylene dibromide or isobutylene dibromide used io action mixture according to the method of the

will. finding one of the excess bromine contained therein

The amount of olefin dibromide to be used is at least an equimolar amount of an olefin or oil depending on the solubility of the aromatic compound to be mixed in, especially ethylene or propylene, in this solution. The olefin, especially the ethylene or the solvent and, on the other hand, according to the viscosity 15, propylene, or olefin mixture sets with the over the reaction mixture during the bromination. The amount of bromine to the corresponding dibromides of the olefin dibromide is preferably around. If the bromination in ethylene dibromide has been selected so that the aromatic compound to be brominated has been carried out, ethylene is expediently used, at least partially or completely in it their mixtures, if appropriate during the bromination, remain easily stirrable. These can also be used with other inert gases for this purpose. A necessary amount of olefin dibromide must be a small excess of olefin, which does not interfere with the reuse of the solvent, determined by simple preliminary tests.
will. In most cases, 0.5 to 3.0 moles of olefin dibromide, especially ethylene or propylene conditions, do not occur during the bromination. findibromids, especially of ethylene dibromide or

The solution of the aromatic compound in olefin propylene dibromide. Even with the addition of the dibromide, especially ethylene or propylene dibromide, olefins, especially ethylene or propylene, respectively Per mole about 0.03 to 4.0 parts by weight of a 30 exclusive of the corresponding dibromide. on usual halogenation catalyst, for example in this way the iron from the reaction mixture or aluminum powder or its salts and separate olefin dibromide, especially the ethylene or or iodine added. or propylene dibromide, any number of times as a solvent

It can also be beneficial to reuse it in this way.

obtained mixture still 0.005 to 1.0 weight 35 The solvent losses are in the invention

percent water to be added. proper working method considerably less than with the

In this mixture are now with normal use of other organic solvents, such as or elevated temperature, preferably with a carbon tetrachloride. The solvent losses, the calculated amount of bromine in the process of the invention ErTemperatur between 10 and 6O ⁰ C, and stirring may occur and an excess of 40 are also introduced through the bromination at-0.1 to 10.0 weight percent. If a subsequent formation of solvent from the over-oxidation of the excess bromine and olefin formed during the bromination, especially ethylene or hydrogen bromide, is possible in the reaction vessel, propylene, more than balanced,
the calculated amount of bromine is 1 g atom of bromine per The reaction mixture can, after the conversion, g atom of the hydrogen to be substituted. If the oxidation of the resulting hydrogen bromide carbonate or ammonia solution is first washed acid-free with water or with aqueous sodium outside the reaction vessel, each will be. After separating the aqueous layer from the g-atom of the hydrogen to be substituted, 2 g-atom organic layer, this is used with the usual bromine as the calculated amount of bromine. Desiccants, such as silica gel or fuller's earth,

In most cases, however, it is possible to dry the 50. The desiccant is expediently through

The bromine water formed during the bromination was filtered off.

to oxidize substance by chlorine, which at the same time, then the solvent and the optionally mixed (bromine chloride), with the bromine derivative of diphenyl, diphenyl ether, diphenyl bromine in the reaction mixture and or or in the phenyl ether or the di-, tri- or . Tetraphenyl gas space above it is introduced. The 55 methane separated by distillation.
The brominated products are solid substances only a small part of the total required or yellowish liquids, the viscosity of which is added to the amount of chlorine when it is already high that it hardly contains the entire amount of bromine at room temperature. Appropriate will flow in that. The bromine content of the products which can be prepared by the process of the reaction mixture during the course of the Bro-60 invention is always a small excess of bromine compared to the theoretical value. It is maintained, for example, the amount of chlorine supplied. Only in the case of the pentabromodiphenyl ether 69 to 70.5 percent by weight should be added to the pentabromodiphenyl ether provided by the process of the invention after the end of the bromination that the molar ratio is weight percent and for the pentabromide phenyl 71 to the total amount of bromine and chlorine introduced 65 72.5 percent by weight . The above in discount is about 1. more detailed procedure of the. The chlorine introduced into the reaction mixture or into the invention above it can also be carried out continuously if the gas space is suitably configured.

5 6

The bromination in the presence of chlorine becomes ethereal as light yellow, very viscous and almost odorless

carried out, the brominated end products can be liquid with a content of 70.1 percent by weight

small amounts of aromatically bound chlorine ent- bromine and 0.9 percent by weight of chlorine obtained

keep. However, this chlorine content does not exceed 0.1 mm of mercury at a pressure of 3 percent by weight and remains boiling at 195 to 205 ^° C. at most 5 temperatures. aside from that

Cases below 1 percent by weight. If the after 600 parts by weight of ethylene dibromide are obtained,

Process of the invention produced products for the use as a solvent in a further approach

Flame-proofing of flammable plastics can be used,

set, the low chlorine content does not bother, as it.

without any effect on the effectiveness of the brominated io ^b ) Comparative experiment with carbon tetrachloride
Products remains and no damage to the flame retardant as a solvent
made plastics. Like the chlorine-280 parts by weight of diphenyl ether, the parts by weight of carbon tetrachloride are also suitable in 561-containing brominated products. This non-chlorine-free material is very good for making burns flame-resistant. 2.0 parts by weight of iron powder and bar plastics, especially polyethylene. The 15 added 1.5 parts by weight of iron bromide. Under produced products are the mixture obtained possibilities especially for incorporation into plastics overall i _m over 3 hours, then is 700 parts by weight and diminish together with antimony trioxide bromine and so introduced 300 parts by weight of chlorine as a highly viscous liquid vigorous stirring, how or other of these Purpose known connection it is described above under a).
fertilize the flammability of such plastics 20 After the addition of bromine and chlorine is over. allow the mixture to react for 14 hours

Compared to other known methods where left.

aromatic compounds also in solvents The reaction mixture will then be brominated with, the inventive method 215 parts by weight of a 21% sodium bisulfite has the advantage that the bromination is stirred after rapid dissolution. The organic "starting" separated from it runs very quickly and completely. The layer is washed acid-free with water and, according to the method according to the invention, the reaction can be separated again from the aqueous layer with the mixture and dried on bleaching earth immediately after the end of the bromination. After filtering off the work carried out while carrying out the fuller's earth, the solvent is separated from the penta-bromination of aromatic compounds in bromodiphenyl ether by distilling other solvents, such as carbon tetrachloride, in vacuo. Here, 810 parts by weight of pentabromodiphenyl ether are always required, corresponding to compliance with a post-reaction time - 87.2% of theory. Above all, however, the bromine derivatives can be obtained by the process of the invention with an extremely brownish, viscous and strongly smelling liquid, the bromine content of which is 64.4 percent by weight and a small excess of bromine is 35 and chlorine is 2.2 percent by weight,
Free of toxic and strongly smelling impurities. Only impurities are contaminated with carbon tetrachloride. 400 parts by weight, i.e. 71.3%, recovered. The viscous end products can only be used;
contain, which according to known methods, for. B. through 40

fractional distillation in vacuo or um- Example 2
crystallize from suitable solvents, 280 parts by weight of diphenyl ether are removed in 400 Gewerden. In this way, the pure, more importantly, ethylene dibromide is dissolved. This solution obtained brominated products in crystalline form. 0.5 parts by weight of iron powder and 0.5 Ge Beisoiell ^{45 w} i u ^{e cntste} water was added. While stirring vigorously and maintaining the conditions given in Example 1, a) Bea) method of the invention, 670 parts by weight of 280 parts by weight of diphenyl ether are introduced into 550 parts by weight of bromine and 295 parts by weight of chlorine,
solved by weight ethylene dibromide. Immediately after the end of the bromine and chlorine, 0.4 parts by weight of iron powder and 0.2 parts by weight of ethylene are added to the part by weight of water. With vigorous stirring, reaction mixture is introduced, which is then worked up in the course of 2 hours in the information obtained in Example 1, a).
Mixture then 700 parts by weight of bromine and 300 parts by weight. 892 parts by weight, corresponding to parts by weight of chlorine, are introduced in such a way that the reaction 96% of theory, pentabromodiphenyl ether as a bell mixture, always contains slightly more bromine than chlorine. 55 yellow, almost odorless, but very viscous liquid is. In the course of this addition, the temperature rises. The bromine content of the product is from room temperature to about 55 ^° C. and is maintained at 70 percent by weight and 0.7 percent by weight of chlorine, this value. In addition, 410 parts by weight of ethylene dibromide are obtained immediately after the end of the bromine and chlorine, which are used in further batches to add about 8.5 parts by weight of ethylene in the 60 can.

Initiated reaction mixture. The re-example 3
Action mixture washed acid-free with water. the

is separated from the aqueous organic layer in a solution of 308 parts by weight of diphenyl in

then dried with fuller's earth. After collecting 1200 parts by weight of ethylene dibromide, which still contains 4

Trier the fuller's earth will be the solvent of which 65 parts by weight of iron powder have been added

Pentabromodiphenyl ether by distilling in vacuo at the same time slowly 1408 parts by weight of bromine and

separated. 900 parts by weight, 310 parts by weight of chlorine are introduced. The temperature

speaking 97% of theory, pentabromidiphenyl is slowly brought to 6O ⁰ C during the introduction

7 8

increases and held at this value until the content of bromine and 310 parts by weight of chlorine slowly

of the reaction mixture of free bromine conducts to about. The reaction mixture obtained is as in

1 percent by weight has decreased. Then the first approach is worked up. The yield is

the reaction mixture ethylene passed until the 1604 parts by weight, corresponding to 100% of theory,

free bromine is bound. 5 on octabromodiphenyl ether with a bromine content of

By cooling the reaction mixture to a 78.8 weight percent and a chlorine content of

Temperature of about 10 ⁰ C, the resulting octa- falls 1.9 percent by weight.

bromodiphenyl as a precipitate, which is filtered off, from the remaining mother liquor are in turn

washed and dried. The yield is 900 parts by weight to dissolve another 340 parts by weight

1384 parts by weight, corresponding to 88% of theory, io parts diphenyl ether used and this solution after

further processed on octabromodiphenyl with a bromine content of the above information.

80.8 percent by weight, a chlorine content of 0.9 Ge The yield is 1590 parts by weight,

weight percent and a melting point of 190 to speaking 99% of theory, of octabromodiphenyl

195 ⁰ C. ether with a bromine content of 78.9 parts by weight

The remaining mother liquor is used for a new 15 and a chlorine content of 1.0 percent by weight.

Approach used.

Example 6

In a solution of 340 parts by weight of diphenyl

In a solution of 1540 parts by weight of diphenyl ether in 900 parts by weight of ethylene dibromide, the in 6000 parts by weight of ethylene dibromide to which 20 4 parts by weight of iron powder have been added, 25 parts by weight of iron powder have been added, 2816 parts by weight of bromine are slowly added, 14 080 parts by weight of bromine are slowly introduced. The temperature of the reaction mixture becomes During this time, the temperature of the Re- is increased to 80 ° C and held at this value until action mixture slowly increased to 60 ° C and on the content of the reaction mixture of free bromine this value was held until the content of the reaction gas has fallen to about 0.7 percent by weight. Thereafter mixture of free bromine to 0.8 percent by weight, ethylene is passed into the reaction mixture until has decreased. Then ethylene is bound in the re-the free bromine.

Action mixture initiated until the free bromine by cooling the reaction mixture to a

is bound. Temperature of about 1O ⁰ C falls the Octabromdi-

When cooling the reaction mixture to a 30 phenyl ether. This precipitate is separated Temperature of about 10 ° C falls the resulting octa- washed and dried. The yield is Bromodiphenyl as a precipitate and is filtered off, 1433 parts by weight, corresponding to 89% of theory, washed and dried. The yield is octabromodiphenyl ether with a bromine content of 6890 parts by weight, corresponding to 88% of theory, 79.6 percent by weight, of octabromodiphenyl with a bromine content of 35. . ,

81.1 percent by weight. Example /

The bromine water formed during the bromination - 246 parts by weight of a technical diphenylphenyl

In water, the substance becomes a 50 to 60% bromine ether in 415 parts by weight of ethylene dibromide hydrogen solution absorbed. solved. This solution is 0.4 parts by weight of iron

The powder added during the separation of the Octabromidphenyls 40. Subsequently, in this arising In a new batch, the filtrate is mixed with stirring 528 parts by weight of bromine and Solvent used. Introduced 235 parts by weight of chlorine. The temperature

. . increases from room temperature to about 45 ° C and

^{be! sp} * ^{e [ 5} is held at this value.

In a solution of 340 parts by weight of diphenyl 45 after the addition of bromine and chlorine ether in 900 parts by weight of ethylene dibromide, which is about 6.5 parts by weight of ethylene in the Re-4 Parts by weight of iron powder have been added, initiated action mixture. Then the are at the same time 1408 parts by weight of bromine and reaction mixture with sodium carbonate solution and 310 parts by weight of chlorine slowly introduced. While water washed acid-free and without drying the During this time, the temperature of the reaction mixture is mixed with the 5 ° solvent from the hexabromodiphenylphenyl ether slowly increased to 60 ° C and distilled on this. This gives 679 parts by weight of the ent value held until the content of the reaction mixture speaking 94% of theory, hexabromodiphenylane free bromine has dropped to 0.4 percent by weight. phenyl ether with a content of 65.5 weight-subsequently ethylene is introduced into the reaction mixture percent bromine and 1.1 percent by weight chlorine, until the free bromine is bound. 55 hold. In addition, 438 parts by weight of ethylene-Der on cooling the reaction mixture to dibromide obtained as a solvent to further a temperature of about 10 ° C arising low approaches are used, blow of octabromodiphenyl ether is filtered off,. . washed and dried. The yield is Example 8 1412 parts by weight, corresponding to 88% of theory, 60 in a solution of 168 parts by weight of diphenylane Octabromodophenyl ether with a bromine content methane in 520 parts by weight of ethylene dibromide, the of 79.05 percent by weight and a chlorine content, 0.3 parts by weight of iron powder was added of 1.1 weight percent. 800 parts by weight of bromine are slowly brought into 900 parts by weight of the mother liquor obtained. During this time the temperature will 340 parts by weight of diphenyl ether are dissolved and 65 of the reaction mixture is slowly increased to 95.degree 4 parts by weight of iron powder were added to this solution. and kept at this value. Under the conditions given above in this solution at the same time 1408 parts by weight action mixture is cooled to 50 ° C, and there are

14 parts by weight of ethylene initiated. The reaction mixture is then mixed with sodium carbonate solution and water washed acid-free and the ethylene bromide is distilled off in vacuo. Here will be 512 parts by weight, corresponding to 98% of theory, of brominated diphenylmethane with a content of 68.8 weight percent bromine obtained.

The hydrogen bromide formed during the bromination becomes a 50 to 60% strength hydrogen bromide solution in water absorbed.

The ethylene dibromide distilled off is used for a new approach.

Claims (1)

Claim: Process for the preparation of bromine derivatives of diphenyl, diphenyl ether, diphenylphenyl ether or di-, tri- or tetraphenylmethane with four or more bromine atoms per molecule Reacting the diphenyl, diphenyl ether, diphenylphenyl ether which is at least partially dissolved in a solvent or di-, tri- or tetra- 10 phenylmethane in the presence of small amounts of a halogenation catalyst and optionally Water at room temperature or at an elevated temperature, optionally with the addition of chlorine Bromine, characterized in that the bromination is carried out in the presence of olefin dibromides, especially ethylene or propylene dibromide, carries out as a solvent and after the end of the bromination in the reaction mixture olefins, especially ethylene or propylene, introduced in such an amount that it corresponds to the excess bromine present in the reaction mixture is at least equimolar. Considered publications:
German Auslegeschrift No. 1 050 742;
French Patent No. 1,270,333;
British Patent No. 491,792. Legacy Patents Considered:
German Patent No. 1,161,547. 509 577/417 5.65 © Bundesdruckerei Berlin