DE1543207A1 - Halogenated hydrocarbons - Google Patents

Description

DRS. OWL & BERG DIPL-ING. STAPF

PATENT LAWYERS Dn. Owl & Berg, DIpI. Ing.Stopf, 8 MOndien 13, KurfÖrttenplot * MUNICH 13, den KURFORSTENPIATZ 2

ίο JUN11965

Telephone group no. 364265 Telegram address i PATENTEULE MOndien Bank details! Bayerlsdie Vereinsbank MOndien 453100 Postal check account ι MOndinn 45343

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Attorney's file: 15

HOIISAiTTO CHEKIGALS LIIHTu) D

Monsanto House, 10-18, Victoria Street, London o.vv. 1

England

Halogenated hydrocarbons

The present invention relates to halogenated hydrocarbons, particularly those which can be used as functional fluids can be used.

Liquids with high boiling points and the thermal 9Q9831 / 1545 ^BAD

are stable have a variety of uses in modern technology. Such liquids are particularly valuable when they are also non-flammable are.

Liquids exhibiting these properties are provided by the present invention.

A liquid of the invention is a mixture consisting essentially of brominated biphenyls in which 2,4,4'-tribromobiphenyl and 3 »4» 4'-tribromobiphenyl together form the main component. Other brominated biphenyls that may be present in minor amounts include dibromobiphenyls, other isomeric tribromobiphenyls or tetrabromobiphenyls.

The mixtures are preferably those that are liquid at 150 and at temperatures between 150 and the boiling point of the mixture, however in some cases it is possible to use mixtures that are either solid or contain solids at 15 ° C but liquids are at higher temperatures, for example at 30 ⁰ G.

The liquids can be used as, for example, heat transfer liquids, di-electric media, Plasticizers, solvents and film strength agents.

The combined weight of 2,4,4'-tribromobiphenyl and. 909831/1545 _BAp

-3-

3,4,4'-tribromobiphenyl is generally at least 6O> the weight of the mixture _f, in particular from 75> 1 to

The invention comprises a process for the preparation of a liquid mixture of the invention in which biphenyl, 4-bromobiphenyl or 4 »4'-dibromobiphenyl is implemented with an amount of the brominating agent such that

the product is a mixture of bromobiphenyls in which the tribromobiphenyls form the larger component.

The specified mono- and dibromobiphenyls are intermediate products in the broniation of biphenyl and can, if necessary desired, be isolated before continuing the bromination to the tribromo stage. In practice, however, it becomes common preferred to start with biphenyl and react it with a sufficient amount of the bromination agent to form the desired mixture in a single step. Preferably the amount used is the brominating agent essentially stoichiometric.

The preferred brominating agent is bromine itself, which is used in the presence of a bromination catalyst. Aluminum bromide is a particularly suitable bromination catalyst, although others can be used, for example ferric bromide or iodine. Where the source material Is biphenyl or 4-bromobiphenyl, the bro-

mation with bromine to an intermediate stage causes 9098 3 1 /.15AS

-4-be in the absence of a catalyst.

Sulfuryl bromide is an example of another brominating agent.

A reaction temperature of at least 50 ° is normally employed in carrying out the process of the invention, although the reaction can proceed at lower temperatures, for example at ordinary ambient (room) temperature. The preferred reaction temperature range is from about 75 ° C to about 125 ⁰ G, in particular of about 90 ° to about 110 ⁰ G. Higher temperatures, however, can also be used the way up to, for example, 175 G.

The process can be carried out in the presence or absence of an inert solvent. At temperatures above the melting point of the starting material, it is generally preferred to work without a solvent, but at lower temperatures a solvent is desirable. Suitable solvents are carbon tetrachloride and other perhalogenated hydrocarbons. For certain purposes, it is preferred that the initial reaction product to purify, especially to remove catalyst residue where a catalyst was used. Conventional procedures can be used for this purpose, for example distillation

909831/1545 BAD ^

or washing.

The invention is illustrated by the following example.

example 1

960 g (6 Hol) bromine were added to 462 g (3.0 mol) biphenyl at 95 ⁰ O over 4 hours. 12 grams of anhydrous aluminum bromide was then added, followed by an additional 480 grams (3 moles) of bromine added over 2 hours. The product was washed with a solution of hydrochloric acid prepared by diluting 100 cc of concentrated hydrochloric acid (S.Gr. 1.16) with 200 cc of water, and then distilled under reduced pressure to give 1007 g of a colorless liquid a boiling range from 228 to 280 ⁰ C at a pressure of 24 mm mercury.

To produce a product which is suitable for electrical applications, the colorless liquid was stirred with boiling 10% aqueous sodium hydroxide solution for 2 hours, washed with water and then distilled again. Two fractions were collected. The first had a boiling range from 212 to 222 ⁰ C yisi and a pressure of 23 mm mercury, a bromine content of

909831/1545 -6-bath

56, 5 "/ o and weighed 40 g _t The second had a Üiedebereich from 222 to 26O ⁰ O at a pressure of 23 mm mercury, a bromine content of 62.8;" and weighed öcb g. The second fraction consisted for the most part of 2,4,4'- and 3,4,4'-tribromobiphenyl (the calculated broin content of the same being 61.5%) together with a small proportion of more highly brominated Biphenylene.

The ability of the liquid to withstand high temperatures was determined by determining its decomposition temperature using an isoteniscope according to the method of Blake (J. Chem. Eng. Data, 1961, 6, 87). The decomposition temperature, defined as the temperature at which the rate of isothermal vapor pressure rise is 0.84 mm of mercury per minute, was 380 ^° C.

909831/1545

Claims (13)

P a t requirements: 1. Mixture, consisting essentially of brominated biphenyls, characterized in that 2,4 »4'-tribromobiphenyl and 3,4,4'-tribromobiphenyl together are the larger Form component. 2. Mixture consisting essentially of brominated biphenyls, including 2,4,4'-tribromobiphenyl and 3,4,4'-tribromobiphenyl, characterized in that the combined weight of the 2,4 »4'-tribromobiphenyl and 3» 4,4'-tribromobiphenyl is at least $ 60 of the total weight of the mixture. 3. Mixture of brominated biphenyls including 2,4,4'-tribromobiphenyl and 3,4 _f 4'-tribromobiphenyl, characterized in that 2,4,4'-tribromobiphenyl and 3,4,4'-tribromobiphenyl together from $ 75 to 9OJi des Form the total weight of the preparation, the remaining component or components being dibromobiphenyls, other isomeric tribromobiphenyls or tetrabromobiphenyls. 4. Mixture according to one of the claims 1 to 3 »characterized in that it is a liquid at 3O ⁰ G and at temperatures between 30 ⁰ G and the boiling point 90983 1/1546 F # ö -8 point of the mixture. 5. Mixture according to one of claims 1 to 3 »characterized in that it is a liquid at 15 ⁰ C and at temperatures between 15 ° 0 and the boiling point of the mixture. 6. The method, characterized in that biphenyl, 4 ~ bromobiphenyl or 4,4'-dibromobiphenyl is reacted with an amount of a brominating agent in such a way that the product is a mixture of bromobiphenyls in which Tribromobiphenyls form the larger component. 7. The method, characterized in that biphenyl, 4-bromo biphenyl or 4,4 * -dibromobiphenyl is reacted with the essentially stoichiometric amount of a brominating agent necessary to obtain tribromobiphenyl is required. 8. The method according to any one of claims 6 or 7, characterized in that the brominating agent bromine and at least the introduction of the third bromine atom into the biphenyl nucleus in the presence of a broination catalyst is effected. 9. The method according to claim 8, characterized in that the bromination catalyst is aluminum bromide. 909831/1545 -9 10. Method 6 in accordance with one of claims to 9 "in the fact that it is carried out in a temperature range of 75 ° to 125 ⁰ G. 11. The method according to any one of claims 8 or 9, and 10 depending on either claim : ■ or 9f, characterized in that it comprises the step of removing the catalyst residue from the crude reaction product. 12. Process for the preparation of a mixture of bromobiphenyls, the 2,4,4'-tribroinbiphenyl and 3> 4,4 '~ Contain tribromobiphenyl as the larger components, essentially as described in the example given above. 13. bromobiphenyls, characterized in that they are after a method according to any one of claims 6 to 10 and 12 were obtained. 14 · bromobiphenyls, characterized in that they are after a method according to claim 11 were obtained. BATH ORIGINAL 909831/1545