IL22264A - Preparation of bis-(dibromohydroxyphenyl)-dialkylmethane compounds - Google Patents

Description

It is already to convert dialkylmethane in glacial acetic such into dialkylmethane compounds b reactio with bromine at room i which reaction hydrogen bromide a reaction time of one to two daye the desired bromine derivative is separated from mother liquor with a yield of 70 to of the as an impure crude product has to be by The residual mother liquor is coloured dark blue by the products of side reactions and can be recycled to the at only after a troublesome purification involving high side competin with the formation of the desired derivative also consume a part of the bromine for a part of the glacial acetic acid used as a is brominated under the reaction conditions to be The use of glacial acetic acid as a solvent has in addition the drawback that the desired brominated derivatives frequently crystallize whileabsorbing acetic acid of from which they can only very difficultly be It is furthermore known to react with bromine in a mixture consisting of water and Although this process produces yields of at least of the on the a considerable part of the bromine used is consumed by the formation of the present in reaction mixture only at the coat of a considerable technical Possibilities have been looked for to prepare nuclearly brominated compounds in commercially satisfactory with a simultaneous production of hydrobromic while avoiding the drawbacks described There has now been found a process for the preparation of compounds by the reaction of bromine with compounds in organic solvents and in the presence of According thereto the compound to be brominated is introduced into a mixture of at most by weight of neutral hydrocarbons or methyl bromide or chlorinated or brominated aliphatic hydrocarbons having at least two carbon atoms in the molecule or their and at least by weight of and reacted in this mixture at a temperature of 10 to with 4 molesof bromine per mole of about 1 mol of bromine being used for each of hydrogen to can be converted in one process step into brominated derivatives carrying more than 3 bromine atoms as substituents in the aromatic parts of the With particular such and hydrogen The compounds can prepared by th processes described in Patent Specifications or or in der Deutsehen Chemischen 25 by the reaction of ketones with aryloxy According to the invention the the compounds is carried out in a reaction medium consisting of at most by weight of neutral hydrocarbons or methyl bromide or chlorinated or aliphatic hydrocarbons or their and at least by weight of As neutral benzenlc hydrocarbone there are considered mononuclear aromatic compounds which for benzene have a neutral reaction mixture with these aromatic particularly are not brominated under the conditions Znstead or together the neutral hydrocarbons benzenlc bromide or chlorinated or brominated aliphatic hydrocarbons having at least two carbon atoms in the molecule such for ethyl propyl butyl ethylene ethylene and like or their can be In the process according to the invention can even be carried out if the reaction medium contains only an amount of water smaller than by in this there are obtained only highly impure brominated derivatives of the compounds with more than bromine atoms as substituents only a considerable technical If the reaction medium contains an amount of water of at least by the desired bromlnated derivatives of dialkylmethane compounds are obtained i a high yield pure the water present in reaction medium is a good solvent for th hydrobromic acid forming in the course of the broiaination of the dialkylmethane the choice of the proportion of water in the reaction also depends essentially on the question whether a higher quantity of aqueous hydrobromic acid solution is desired as a for with a water content of the reaction medium about by about to of the hydrogen bromide formin in the course of the bromlnatlon of the dialkylmethane compounds are obtained as a pure which can be recovered for technical use without further purification The residual hydrogen bromide remains dissolved in the water of the reaction medium and can be recovered therefrom as a 50 to aqueous hydrogen bromide For carrying out the process according to the invention the compound to be bromlnated is Introduced into the reaction The mixture thus obtained is then admixed with the bromine slowly and with continuous During this operation the reaction is maintained at room The quantity of bromine should amount to for each the to bromlnated and must be so dosed that mol of bromine is introduced into the reaction mixture for each gram atom of crystalline In most cases it is advantageous the reaction mixture after the completion of addition of the to temperatures of to and to keep it at this temperature for some time with continued The initially as a rule finely crystallized precipitate is redlssolved thereby at least to a large During the subsequent cooling of reaction mixture the desired brominated derivative is obtained as a coarsel crystallized precipitate which can easily be separated from the reaction mixture by The washed with water and then if of outstanding purity and can therefore be used fo technical applications without further filtrate is separated an organic and an aqueous By concentration of the organic phase a small remainde of the brominated derivative of the compound introduced can still be isolated from For the the organic phase of the reaction medium can be recycled to the process after simple purification by The aqueous phase of the reaction is equally and a 50 to 60 aqueous hydrogen bromide solution of high purity obtained as a which c an be used as it is for known technical By the process according to the invention it is now possibl prepare a single in a high yield and outstanding brominated derivatives of compounds in the molecul positioned as intermediates which are further processed into bromine containing phenyl which are suitable for the proofing of synthetic I addition up to by weight of hydrogen bromide forming in the of the can be recovered in the gaseous and the remainder as an aqueous solution which ie equally useful The invention is illustrated by the following to which it is not Example 1 1140 parts by weight of dimethylm are suspended in a mixture of 2000 parts by weight of benzene and 500 by weight of 3260 parts by weight of bromine are dropped into the mixture in the course of 120 minutes with continuous stirring while the temperature of the reaction mixture is being maintained at Subsequently the reaction mixture is heated to a temperature of and stirred for some more time at this By cooling of the reaction mixture to a temperature of coarsely crystalline is obtained after separation from the reaction is washed with A ter drying there are obtained 2470 parts by or of the of a pure white product with a bromine content of by which melts at 172 to Afte the separation of the aqueous phase about of the benzen contained in the organic phase are distilled off from the and by cooling of the quantit of methane is The remainder of th benzene can be distilled off om the filtrate obtained in this yield of dimethylmethane amounts to altogether 2530 parts by or of the 1190 parts by or of the of anhydrous gaseous hydrogen bromide and 382 parts by or of the of hydrogen bromide in the form of a aqueous solution are separated or Example 2 114 parts by weight of dimethylmethane are mixed 200 parts by weight of butyl bromide and 50 parts by weight of 327 parts by weight of bromine are added dropwlse and with continuous stirring to this mixture in the course of 120 minutes while of the reaction mixture is maintained at Subsequently the reaction mixture heated to a temperature and stirred at this temperature fo some more By cooling to a temperature of coarsely crystalline dimethylmethane is after separation from the mother is washed with water and subsequently There are obtained 234 parts by or of the of pure with a bromine content of by weight which melts at a temperature of 172 to of the filtrate proceeds in accordance with the indications Example gaseous hydrogen The remaining hydrogen bromide is obtained in the form of a aqueous Example 114 parts by weight are mixed with 200 by weight of ethylene bromide and 50 parts by of water and reacted with parts by weight of in accordance with the indications in There are obtained 206 parts by or of the theory of pure white product with a content by which melts at a temperature of 171 to A further 40 parts by of are recovered from organic phase of the so that the total yield amounts to 2 parts b or of the In 114 by or of the of gaseous anhydrous hydrogen bromide are The remaining hydrogen bromid is obtained in the form of a aqueous insufficientOCRQuality

Claims (1)

1. NOW particularly described and ascertained nature of our said invention and in what manner the same la to he we declare that what we A process for the preparation of compounds wherein a is introduced into a mixture of at most by weight of neutral benzeaic hydrocarbons or methyl bromide or chlorinated or brominated aliphatic hydrocarbons with at least 2 carbon atoms in the or mixtures and at least by weight of and reacted in this mixture at a temperature of 10 to with 4 moles of bromine per mole of the bromine being used in an amount of about 1 for each of hydrogen to be A process for the preparation of compounds substantially as described herein with reference to the when prepared by the process according to Claim 1 or this 15th day of For insufficientOCRQuality