NZ217064A - Brominated hydroxyaromatic compound - Google Patents

Description

New Zealand Paient Spedficaiion for Paient Number £17064 NEW ZEALAND PATENTS ACT,1953 No Date /■ COMPLETE SPECIFICATION BROMINATED HYDROXYAROMATIC COMPOUNDS 74UgJ98$ £ We, THE DOW CHEMICAL COMPANY, 2030 Dow Center, Abbott Road, Midland, Michigan 48640, United States of America, a corporation organized and existing under the laws of the State of Delaware, United States of America, hereby declare the invention for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: (fo11 owed by page la) - la - 217 0G-1 BROMINATED EYDROXYAROMATIC COMPOUNDS The present invention relates to the preparation of brominated aromatic compounds and epoxide derivatives of such brominated aromatic compounds.

More specifically, it relates to ring brominated 5 hydroxyaromatic compounds and ring brominated epoxy aromatic compounds.

It is known to prepare brominared alkyl phenols. See, e.g.. Can. J. Chem., Volume 61, pages 1045-1052 (1983); and Russian Chemical Reviews, Volume 10 32, pages 75-93 (1953). Brominated tetraalkylhydroxy-aromatic compounds having 2 aromatic rings also have been prepared in the past. 3rominated tetraalkyl biphenols having the benzene rings directly linked have been prepared from tetraalkyl diphenoquinones; 15 see, e.g., U. S. Patents 3,929,508; 3,955,403 and 4,0 58,570. However, when compounds having aromatic rings and an alkylene bridge are brominated, the products typically do not have bromine on the aromatic rings. For example, Bradley and Sanders, 20 J. Chem. Soc., Volume 1962, pages 480-486 (1962) r, -j t-: r ~ • i i 0 u i disclose the reaction, of 3,3',5,51-tetra-t-butyl-stilLe.iequir.cne with HBr to yield cr, 3-ci.brc.~o-4, -4'-dihydroxy-3,31,5,5'-tetra-t-bu-ylcibenzyl. Kharasch ana Joshi, J. Ore. Chem., Volume 22, pages 1435-1438 (1957) disclose the reaction of bromine with 4,4'-methvlenebis(2,6-ditertiarybutvlphenol) in the presence of acetic acid to give l-bromo-l, 1-bis--(3,5-ditertiarybutyl-4-hydroxyphenyl)methane.

The compound 2,2'-(1,2-ethaneciyl)bis(3,5--dibromo-4,6-dimethylpnenol) has been prepared by the hydrogenation of 41,5,6',7-tetrabromo-2',51,6,8-tetra-methvl-3,4-cihydrospiro(2H-l-benzopyran-2,1'-[3,5]-cyclohexadien)-2'-one; Ann., Volume 543, pages 48-77 at page 57 (1939); and by the brominaticn of 2;2'-(l,2--ethanedivl) bis (4, 6-diniethylphenol).

In view of the deficiencies of prior art bromination methods, it would be desirable tc have a simple method for the preparation of novel ring brominated polymethyiene-bridged di(dialkylhydroxyarc-manic) compounds having terminal para hydroxy! moieties. Such a method would be useful in the preparation of novel epoxy derivatives of said compounds.

The present invention concerns a process for the preparation of a compound of the formula N X J y Ha\0)—ch~" R X R a 1 -C-! R d v / X tl .CH, \ M OH n Br R wherein n is zero or a positive integer of up to 12, each X ^ independently is Br or H, each R& independently is H or °alkyl of up to 12 carbon atoms, and each R independently i-s'.a primary or secondary alkyl moiety of up to 6 carbon ^-8SEP ;££(itoms, which process is characterized in that (a) a „ -o '' - ~ r -t >■*1 n * ( tetraalkyl dihvdroxydiaromatic polymethvlene-bridgec compound (hereinafter referred to as TDDPC) of the formula (III) wherein n is zero or a positive integer of up to 12, each Ra independently is E or alkyl of up -co 12 carbon atoms, and each R independently is a primary or secondary alkyl moiety of up to 6 carbon atoms is contacted with a bromination agent in the presence of a reaction medium and, optionally, a bromination catalyst to form a reaction mixture; (b) the temperature of the reaction mixture is then raised to an elevated temperature until the reaction is completed; and (c) the resulting compound of Formula I is recovered.

The present invention also concerns a compound of the formula: ^ c " r ■ // X /O \\ {!Z r':! \ -8 SEP 1989^ wnerem n is zero or a positive integer of up to 12, each X independently is Br or H with proviso that at least one X is E, each independently is H or alkyl of up to 12 carbon atoms, and each R independently is a primary or secondary alkyl moiety of up to 6 carbon atoms. v V,^ <?/ -3- Surprisingly, the polymethylene-bridge does not cleave under bromination conditions, nor do the products contain benzyl bromine atoms. The ring brominated novel compounds of the invention are highly stable and are useful as chemical intermediates in the preparation of valuable chemical compounds.

For example, the compounds of the present invention can be reacted with epichlorohydrin using known techniques to give the corresponding epoxy resins, or with polvisocvanates to form polyurethanes, or can be employed in other reactions requiring reactive hydroxyl groups. The compounds are useful as flame retardants due to their bromine content.

New Zealand Patent Specification No. 22S571 is directed to novel epoxy derivatives of ring-brominated polymethyiene-bridged di(dialkvlhydroxyaromatic) compounds of Formula I. The epoxides have terminal para epoxy moieties and at least one bromine atom meta relative to at least one of said epoxy moieties and are represented by the following formula wherein n is zero or a positive integer of up to 12, each X independently is bromine or hydrogen, each R inae- — ci pendently is hydrogen or alkyl of up to 12 carbon atoms, each R independently is a primary or secondary alkyl moiety of up to 6 carbon atoms, and each Z independently is a moiety having a terminal epoxide moiety. The ring-brominated novel epoxy compounds are highly stable and are useful as chemical intermediates in the preparation of valuable chemical compounds. For example, the epoxide compounds can be employed in the preparation of cured epoxy resins. The epoxide compounds of Formula II are prepared by contacting compounds of Formula I with haloalkvlene oxides under reaction conditions.

Preferred TDDPC compounds are represented generally by the formula: /■ s / wherein n is zero or a positive integer of up to 12, each independently is H or alkyl of up to 12 carbon atoms, and each R independently is a primary or secondary alkyl moiety of up to 6 carbon atoms. Preferably, each Ra independently is H or alkyl of up to 6 carbon atoms, and each R independently is alkyl of up to 3 carbon atoms. R most preferably is methyl, R most ci preferably is H, and n most preferably is zero. It should be noted that the process of the present invention can be employed to put additional bromine atoms on partially brominated TDDPC compounds.

A brominating agent is employed in the practice of the present invention. while it may be possible to employ known brominating agents which are useful for the broraination of aromatic rings, bromine 5 is the preferred brominating agent when high purity products are desired. The amount of bromine to employ depends upon (1) the amount of bromine in the product desired, and (2) whether a catalyst is employed. In -—v general, less bromine is required when a catalyst is employed. For example, if the aibromo-product is desired, then stoichiometry would indicate that at least 2 moles of bromine atoms are required per mole of substrate compound to be brominated. Typically, with a catalyst, a stoichiometric excess of bromine ranging 15 from 0 to 25 percent or more is employed; preferably, a stoichiometric excess ranging from 5 to 15 percent is employed. Typically, up to 12 moles of bromine are employed per mole of TDDPC in the production of tetra-brominated products when operating without a catalyst. 20 Smaller excesses of bromine typically require longer reaction times. Similarly, if a brominating agent is employed which is not bromine, the amount of said agent to be employed should provide bromine in the quantities _ stated hereinabove.

A bromination catalyst is optionally employed in the process of the present invention. Friedel-Crafts catalysts are preferred, and are well known. Examples of bromination catalysts include the halides of metals such as iron, aluminum, and tin. Examples of preferred 30 catalysts include aluminum bromide and aluminum chloride, with aluminum chloride being most preferred. The catalyst is employed in catalytic quantities. Preferably, the amount of catalyst employed ranges from 0.1 33,739A-F 2 .<=• to 5 weight percent of catalyst based on the mass of aromatic compound employed. Larger amounts of catalyst may be employed, but may be economically impractical. The catalyst may be employed in a variety of forms.

A reaction medium advantageously is employed in the process of the present invention. The reaction medium functions to solubilize the reactants and reac-tion products, and to aid in heat transfer. While the amount of reaction medium employed may range widely, 10 the amount of reaction medium to be employed generally is indicated by practical considerations, and typically ranges from about 8 to about 20 moles of reaction medium per mole of aromatic compound. Preferably, from 10 to 15 moles of reaction medium are employed per mole 15 of aromatic compound. Typical solvents include the halogenated lower alkanes including the perhalogenated lower alkanes such as methylene chloride, carbon tetrachloride, 1,2-dichloroethane etc. However, it is to be noted that carbon tetrachloride is the preferred solvent 20 due to its physical properties.

The order of addition of the reactants is not • critical. However, according to a preferred process of the present invention, a brominating agent is slowly added to a mixture comprising a reaction medium, a 25 TDDPC, and, optionally, a bromination catalyst. When the addition of the brominating agent is complete, the resulting reaction mixture typically is brought to elevated temperature until the reaction is completed.

The initial addition temperature, i.e., the 30 temperature of the reaction mixture during the period of addition of the brominating agent thereto, typically 33,739A-F "*7 ^ -S- is a temperature at which the reaction mixture is a liquid. Preferably, the initial addition temperature is up to 30°C. More preferably, the addition temperature ""<Bs is from 20°C to 30°C. Most preferably, for the sake of convenience, ambient temperature is employed.

As stated hereinabove, when the addition of the brominating agent to the reaction mixture is com-plete, the total reaction mixture can be heated to elevated temperature in order to assure complete bro-10 mination. Typically, the total reaction mixture is heated to reflux temperature and said temperature is maintained until the reaction is complete. Completion of the reaction can be observed by following the rate of evolution of hydrogen bromide from the reaction 15 mixture, i.e., the reaction is complete when the rate of hydrogen bromide evolution falls to zero. Ordinarily, the reaction will proceed at atmospheric pressure or higher, but subatmospheric pressure can be employed if desired.

The total reaction time of from 1 to 100 hours, depending primarily on the aromatic reacting, is generally adequate for complete reaction under the conditions of the invention. Typically, a total reaction time of up to 20 hours will be sufficient to 25 produce high yields of high assay products. In some cases, bromination may be complete in 3 hours or less. It is desirable to add the brominating agent to the reaction mixture at a sufficiently slow rate to minimize loss of bromine and reaction medium, and to permit 30 the desired low addition temperature to be maintained under conditions of control and safety. a; 33,739A-F 2 A When the reaction is carried out as described hereinabove, a brominated TDDPC of Formula I will be formed. Preferably, at least one X moiety in Formula I is Br. Most preferably, two or three X moieties in 5 Formula I are Br.

The reaction mixture resulting from carrying out the process of the invention can be processed by a variety of known work-up procedures to isolate the brominated products. The crude reaction mixture, which 10 may contain the brominated products, excess reaction medium and excess catalyst, can, for instance, be subjected to stripping either at atmospheric pressure or preferably under reduced pressure to the point of constant weight of the residue. The crude product which 15 is thus isolated may be further purified, for instance, by recrystallization or by digestion with a recovery medium such as acetone, toluene, or dilute hydrochloric acid. This isolation method by stripping is fast, simple and gives reliable yield data and relatively 20 pure product. It is preferred to employ a work-up method which neutralizes bromine. The yield of pure product, i.e., the numerical product of conversion of TDDPC, selectivity to the desired product, ana purity of the desired product, typically is at least 50 mole 25 percent. Preferably, the yield is at least 60 mole percent, and more preferably, the yield is at least 75 mole percent.

It is generally possible to predict the product(s) which will result from application of this 30 perbromination process under optimum reaction conditions to any particular starting material. The general 33,739A-F r 4 r? r. ;~ >- _L l \J rule is that every nuclear hydrogen atom of the aromatic compound will be replaced by a bromine atom if the reaction is carried to completion, that is, until the evolution of hydrogen bromide has stopped. This level of bromination may be reached by proper adjustment or reaction temperature, catalyst concentration, if any, and reaction time. The bromination process is continued until such time as the sampling indicates that the desired degree of bromination has been reached, or the bromination reaction may be continued until evolution of hydrogen bromide has substantially ceased.

As stated hereinabove, the epoxide compounds of Formula II are prepared by contacting a brominated TDDPC of Formula I with a haloalkylene oxide under reaction conditions such that there is formed an epoxy derivative of a brominated TDDPC.

Typical haloalkylene oxides are represented generally by the formula /°\ X~C(Rb)2CRb C(^b)2 (IV) wherein X is halo, and each independently is H or an aliphatic or inertly-substituted aliphatic moiety of up to 25 carbon atoms. Preferably, each R^ is E, and X is chlorine or bromine, with chlorine being more preferred. Examples of haloalkylene oxides desirably employed in the process include chloropropylene oxide, iodopropyl-ene oxide, methyl epichlorohydrin, methyl epibromo- hycirin, methyl epiiocohydrin, chlorobutylene oxide, bromoprcpylene oxide, and the like of up to 5 carbon atoms, with chlcropropvlene oxide (epichloro'nydrin) being preferred. Mixtures of haloalkylene oxides can be employed.

The reaction conditions employed for the addition of haloalkylene oxides to hydroxvl-containing or active-hydroger.-containing compounds are well-known. See, e.g.. Handbook of Edoxv Resins, by Lee and Neville McGraw-Hill (1967); and U.S. Patent 4,284,573. Said known conditions are advantageously employed in the preparation of the epoxide compounds cf Formula II - Typically, for example, from 3 to 50 moles of haloalkylene oxide are employed per mole of active hydrogen atoms in the brominated TDDPC, with a preferred amount being from 10 to 25 moles per mole.

Larger or smaller amounts can be employed if desired. The contacting can be performed at any combination of temperature and pressure at which the desired reaction will proceed. Typically, the contacting is performed at elevated temperature. Preferably, the temperature is from 60°C to the boiling point of the haloalkylene oxide. Ambient pressure is preferred for the sake of convenience.

A catalyst is optionally employed, and can be selected from known catalysts for this reaction, inclua ing the wide range of catalysts mentioned in the references cited previously herein. Examples of preferred catalysts include, for example, tetraethylammonium bromide, ethyltriphenyl phosphonium acetate and the • like.

When the brominated TDDPC of Formula I and haloalkylene oxide of Formula IV are contacted as described hereinabove, an epoxy resin is produced which is an epoxy derivative of the brominated TDDPC. Examples of typical epoxy resins arc represented by the formula: wherein n , X, R£, R and 2 are as hereinbefore defined. The 2 moieties correspond to the structure of the haloalkylene oxide employed. For example, when epichlorohydrin is the haloalkylene oxide, 2 is a moiety of the formula: /°\ -CH2-CH-CH2 ' .

The epoxy resins of Formula II can be cured to form novel epoxy polymers having surprisingly improved properties. Thus, in another embodiment, New Zealand Patent Specification No. 229571 is also directed to a composition comprising an adduct of (a) a compound of Formula II; (b) a curing agent for epoxy resins; and, optionally, (c) a curing catalyst. The epoxy resins can be cured using well-known techniques. The novel cured resins typically are prepared by heating the polyepoxide 2 £ - -*"s compounds with a curing agent, typically at a temperature of from 0°C to 300°C, and preferably from 25°C to 250°C.

As curing agents there can, for example, be 5 mentioned: amines or amides such as aliphatic, cyclo-aliphatic or aromatic primary, secondary and tertiary amines, for example, monoethanolamine, ethylenediamine, hexamethylenediamine, trimethylhexamethylenediamine, diethylenetriamine, triethylenetetramine, tetraethvlene-10 pentamine, N,N-dimethylpropylenediamine-l,3, N,N-die-thvlpropylenediamine-1,3, bis(4'-amino-3-methylcyclo-hexvl)methane, 2,2-bis(4'-aminocyclohexyl)propane, 3,5,5-trimethyl-3-(aminomethyl)cyclohexylamine ("iso-phoronediamine"), N-aminoethylpiperazine, Mannich 15 bases, such as 2,4,6-tris(dimethylaminomethyl)phe-nol; m-phenylenediamine, p-phenvlenediamine, bis-(p-aminophenvl)-methane, bis(p-aminophenyl)sulfone and m-xylylenediamine; adducts of acrylonitrile or monoepoxides such as ethylene oxide or propylene 20 oxide to polyalJcylenepolyamines such as diethylene-triamine or triethylenetetramine; adducts of poly-amines such as excess diethylenetriamine or tri-ethylenetetramine, and polyepoxides such as aiphe-nylmethane polvglycidyl ethers; ketimines, for 25 example, from acetone or methyl ethyl ketone and bis(p-aminophenyl)methane; adducts of monophenols or polyphenols and polyamines; polyamides, especially those from aliphatic polyamines, such as diethylenetriamine or triethylenetetramine and 30 dimerized or trimerized unsaturated fatty acids such as dimerized linseed oil fatty acid ("VERS-AMID"); polymeric polysulfides ("THIOKOL"); dicy- 33,739A-F 2 T * Jg anaiamide; aniline-formaldehyde resins; polyhydric phenols, for example, resorcinol, 2,2-bis(4-hydroxy-phenyl)propane or phenol-formaldehyde resins; boron trifluoride and its complexes with organic compounds, 5 such as BF2 ether complexes and BF3 amine complexes, for example, BFg-monoethylamine complex; acetone-acetanilide-BF3 complex; phosphoric acid, triphe-nylphosphite, polvbasic carboxvlic acids and their anhydrides, for example, phthalic anhydride, tetra-10 hydrophthalic anhydride, hexahydrophthalic anhydride, 4-methylhexahydrophthalic anhydride, 3,6--endomethylene-tetrahydrophthalic anhydride, methy1-3, 6-endomethylene-tetrahydrophthalic anhydride, (methylnadicanhydride), 3,4,5,6,7,7-15 -hexachlor-3,6-endomethylene-tetrahydrophthalic anhydride, succinic anhydride, adipic anhydride, azelaic anhydride, sebacic anhydride, maleic anhydride, dodecenyl-succinic anhydride; pyromellitic dianhydride or mixtures of such anhydrides.

It is particularly advantageous x.o use curing agents which in themselves yield molding materials of good electrical properties, such as especially cycloaliphatic dicarboxylic acid anhydrides such as, for example. A4-tetrahydrophthalic 25 anhydride or hexahydrophthalic anhydride, or cycloaliphatic polyamines such as, for example, 2,2-bis-(4'-aminocyclohexvl)propane or "isophoronediamine".

It is furthermore possible to use cure accelerators during the cure, and in particular 30 when using polyamides, polymeric polysulfides, dicvandiamide or polycarboxylic acid anhydrides 33,739A-F j K*- r■ K i « ^ as curing agents; such accelerators are, for example, tertiary amines, their salts or quaternary ammonium compounds, for example, 2,4,6-tris(dimethyl aminomethyl )phenoi, benzvldimethylamines, 2-ethyl-4-methylimidazole or triamylammonium phenolate; or alkali metal alcoholates such as, for example, sodium hexanetriolate.

The expression "cure" as used here denotes the conversion of the above adducts containing epoxide groups into insoluble and infusible cross-linked products, and in particular as a rule with simultaneous shaping to give shaped articles such as castings, pressings or laminates, or to give two-dimensional structures such as coatings, lacquer films or adhesive bonds.

If desired, it is possible to add active diluents such as, for example, styrene oxide, butvlglycidyl ether, isooctvlglycidyi ether, phenvlglvcidyl ether, cresylglvciayl ether or glycidyl esters of synthetic highly branched mainly tertiary aliphatic monocarboxylic acids ("CARDURA E"), or cycloaliphatic monoepoxides such as 3-vinyl-2,4-dicxaspiro (5,5 )-S,10-epoxy-undecane.

The above adducts can furthermore be mixed with other curable diepoxide or polyepoxide compounds- As such that can, for example, be mentioned: polyglvcidyl ethers of polvhydric alcohols such as 1,4-butane-diol, polyethylene glycols, polypropylene glycols— r. i ry r> -• ^ i i Vx >J or 2,2-bis(4'-hvdroxycyclohexyl)propane; polygly-cidyl ethers of polynydric phenols such as 2,2-bis-(4'-hydroxyphenyl)-propane, 2,2-bis(4'-hydroxy--3,5'-dibromophenvl)-propane, bis(4-hydroxyphenvl)-sulfcne, 1,1,2,2-tetrakis(4-hydroxyphenvl)ethane or condensation products of formaldehyde with phenols produced in an acid medium, such as phenol novolacs or cresol novolacs; polyglycidvl esters of polycarboxylic acids such as, for example, phthalic acid diglvcidvl ester, tetrahvdrophtha-lic acid diglyciayl ester or hexahydrophthalic acid diglvcidvl ester; triglycidvl isocyanurate, N,N*-diglycidyl-5,5-dimethvl hvdantoin, or amino-polvepoxides such as are obtained by aehydrohalo-genation of the reaction products of epihalogeno-hydrin and primary or secondary amines such as aniline or 4,4'-diaminodiphenylmethane; also ali-cyclic compounds containing several epoxide groups, such as vinvlcyclohexene-diepoxide, aicyclopentadi-eneaiepoxide, ethylene glvcol-bis(3,4-epoxytetra-hydrodicyclopentadien-8-yl)ether, (3,4-epoxycyclo-hexylmethyl)-3,4-epoxvcyclohexanecarboxylate, (3',4'-epoxy-6'-methylcyclohexvlmethyl)-3,4-epoxy--6-methylcyclohexanecarboxylate, bis(cvclopentvl)-ether diepoxide or 3-(3',4'-epoxvcyclohexyl)-2,4--dioxaspiro-(5,5)9,10-epoxyundecane.

The subject matter of Kew Zealand Patent Specification No. 229571 therefore also includes curable mixtures which are suitable for the manufacture of shaped articles including two-dimensional structures and which contain the so-called "advanced" adducts containing r. -* r*. n ~' ± (VO epoxiae groups, optionally together with other diepoxide or polvepoxice compounds and also curing agents for epoxide resins such as polyamines or polvcarboxylic acid anhydrides.

The compounds of Formula II, or their mixtures with other polyepoxide compounds and/or curing agents, can furthermore be mixed, at any state before cure, with usual modifiers such as extenders, fillers and reinforcing agents, pigments, dvestuffs, organic solvents, plasticiz-ers and the like.

As extenders, reinforcing agents, fillers and pigments which can be employed in the curable mixtures there can, for example, be mentioned: coal tar bitumen, glass fibers, boron fibers, carbon fibers, cellulose, polyethylene powder, polypropylene powder, mica, asbestos, quartz powder, slate powder, aluminum oxide trihydrate, chalk powder, gypsum, antimony trioxide, bentones, silica aerogel ("AEROSIL") lithopone, barite, titanium dioxide, carbon black, graphite, iron oxide or metal powder such as aluminum powder or iron powder.

The following are, for example, suitable as organic solvents for modifying the curable mixtures: toluene, xylene, n-prcpanol, butyl acetate, acetone, methyl ethyl ketone, aiacetone-alcohol, ethylene glycol, monomethyl ether, monoethyl ether and monobutyl ether. 2 1/05 Dibutyl, dioctyl and dinonyl phthal-ate, tricresyl phosphate, trixylenvl phosphate and also polypropylene glycols can, for example, be employed as plasticizers for modifying the 5 curable mixtures.

Especially for use in the lacquer field, the new adducts containing epoxide groups can furthermore be partially or completely esterified in a known manner with carboxvlic acids, such as espe-10 cially higher unsaturated fatty acids. It is furthermore possible to add other curable synthetic resins, for example, phenoplastics or aminoplas-tics, to such lacquer resin formulations.

It is furthermore also possible to add 15 other usual additives, for example, agents for conferring thixotropy, flow control agents such as silicones, cellulose acetobutyrate, polyvinyl butyral, waxes, stearates and the like (which are in part also used as mold release agents) 20 to the curable mixtures.

The curable mixtures can be manufactured in the usual manner with the aid of known mixing equipment (stirrers, kneaders, rollers and the like).

The curable epoxide resin mixtures referred to hereinabove can be employed in the fields of surface protection, the electrical industry, laminating processes and the building industry. They can be used in a formulation 33,739A-F -18- 2 r; Ob-i which is in each case suited to the particular end use, in the unfilled or filled state, optionally in the fora of solutions or emulsions, as paints, lacquers, sintering powders, compression 5 molding compositions, dipping resins, casting resins, injection molding formulations, impregnating resins and adhesives, as tool resins, laminating resins, sealing and filling compositions, floor covering compositions and binders for nsin-10 eral aggregates. field of compression molding powders and of sintering powders. Eere the epoxide resin powder mixtures can be processed without pressure or with 15 pressure, according to known processes such as fluicized bed sintering, electrostatic fluidized bed sintering, spraying, electrostatic spraying, compression molding and the like.

The following Examples and Comparative Experi-20 ments are given to illustrate the invention and should not be construed as limiting its scope. All parts and percentages are by weight unless otherwise indicated.

Examole 1 bisphenol E was suspended in 75 ml of CCl^. A 4.2 ml portion of bromine (0.082 mole) was added at 23-25°C, and the mixture was heated to reflux. All of the bromine has A main field of application lies in the Preparation of 4,4'-(1,2-ethanediyl )bis(3-bromo--2 , 6-aimethvlphenol) (Dibromotetramethvlbisphenol E) A 20.0 g (0.074 mole) portion of tetramethyi- reacted by that. time. Analysis by gas chromatography (GC) and NMR indicated the following composition: 42 area percent starting material, 14 area percent mono-fa romotetr amethyl-bis phenol E, and 43 area percent 5 dibromotetramethylbisphenol E. After adding 4.2 more ml of bromine, the mixture was refluxed for 1.5 hrs and analyzed by GC; the following composition was obtained: area percent starting material, 7 area percent monobrominatea product, 90 area percent dibrominated 10 product, and 1 area percent tribrominated material. Cooling of the slurry to 25°C and filtration of the insoluble solid gave 29.2 g of a brown solid which melts at 191-194°C. Recrvstallization from toluene gave a solid which melts at 194-197°C and has the following 15 composition: 5 area percent monobromo, S3 area percent dibromo, and 2 area percent tribromotetrainethy lbisphenol E. The NMR spectrum is consistent with the proposed structure: ~H NMR (acetone d^) 6: 2.20 (s, 6H, -CH^), 2.36 (s, 6H, -CH3), 2.86 (s, 4H, -CH--), 6.38 (s, 2H, 20 —CH), and 7.35 (s, 2H, —OH).

Example 2 Preparation of 3,5-dibromo-4-(2-(2-bromo-4-hydroxy--3,5-dimethylphenyl)ethyl)-2,6-dimethylphenol (Tri bromotetramethvlbisphenol E) A 12.5 g (0.046 mole) portion of tetramethyl- bisphenol E was suspended in 100 ml of CClA, and 12.0 ml (0.234 mole) of bromine was added at 23-25°C. After refluxing the mixture for 1.0 hr, the following composition was observed: 16 area percent dibromo, 77 area 30 percent tribromo, and 7 area percent te trabromotetramethy1-bisphenol E. The unreacted bromine was removed by 2 $ if distillation. More CCl^ was added (50 ml), and the slurry is cooled to 25°C. Filtration of the insoluble solid afforded 18.2 g of a brown solid which melts at 249-255°C. Recrystallization from toluene afforded a 5 gray-brown solid which melts at 257-262°C, and has the following composition: 6 area percent dibromo, 78 area percent tribromo, and 16 area percent tetrabromotetra-methylbisphenol E. It has the following NMR spectrum: XH NMR (DMSO dg) 5: 2.12 (s, 3H), 2.28 (s, 9H), 3.20 10 (s, 4H), and 6.90 (s,lH).

Example 3 Preparation of 4,4'-(1,2-ethanedivl)bis(3,5-dibromo--2,6-dimethylphenol) (Tetrabromotetramethvlbisphenol E) A 27.1 g (0.1 mole) portion of tetramethyl-15 bisphenol E was suspended in 100 ml of CCl^. A 60 ml (1.17 mole) portion of bromine was added dropwise while keeping the temperature below 30°C using a water bath for cooling. Immediate evolution of HBr was observed. The mixture was brought to reflux for 2 hrs. The 20 excess bromine was removed by distillation with the aid of 200 ml of CCl^. The mixture was cooled to 25°C, and the insoluble solid was filtered. This afforded 52.0 g of brown solid which melts at 290-297°C. Purification of the insoluble solid involved suspending it in 100 ml 25 of acetone, refluxing for 1.0 hr, cooling to 25°C, and filtering the insoluble solid. A white solid was obtained, 46.0 g, which melts at 295-297°C and has the following composition: 75 area percent tetrabromo and 25 area percent tribromotetrainethy lbisphenol E. The "^H NMR spectrum (DMSO d^) has a small singlet at 2.12 6 and 2 major peaks, a singlet at 2.26 5, and a singlet at 3.20 6, in a ratio of 3 to 1. This spectrum is consistent with the proposed structure. 33,739A-F Example 4 Bromination Using A Friedel-Crafts Catalyst A 136 g (0.5 mole) portion of tetramethy1 bisphenol E is suspended in 1,400 ml of CH2Ci2. Fol-5 lowing the addition of 2.0 g of FeCl3, 86 ml (1.65 mole) of bromine was added at 20-24°C. After refluxing the mixture for 2.0 hr all of the bromine had reacted. A portion of the solvent, 300 ml, was removed by distillation, and the slurry was cooled to 25°C. Fil-10 tration of the insoluble solid afforded 262 g of a light brown solid which has the following composition: 8 area percent dibromo, 58 area percent tribromo and 34 area percent tetrabromo tetramethyl-bisphenol E. The NMR spectrum is consistent with this composition.

Comparative Experiment 1 - Not an embodiment of the present invention.

Bromination of Tetramethylbisphenol F.

A 25.6-g portion of tetramethylbisphenol F (0.1 mole) was suspended in 125 ml of carbon tetra-20 chloride, and the slurry was cooled to 5°C. A 6-ml portion of bromine (0.12 mole) was added dropwise, and the mixture was stirred for 15 minutes. All of the bromine reacted. Analysis of the mixture by gas chromatography indicates that >90 percent of the 25 starting material reacts. The major product formed was 4-bromo-2,6-dimethylphenol, which was identified by comparison with an authentic sample; a number of other cleavage products were formed. Addition of 6 more ml of bromine gave complete cleavage of the tetramethyl-30 bisphenol F. 33,739A-F Comparative Experiment 2 - Not an embodiment of the present invention.

Bromination of Tetramethylbisphenol A.

A 14.2-g portion of tetramethylbisphenol A 5 (0.05 mole) was suspended in 100 ml of carbon tetrachloride, and the slurry was cooled to 5°C. A 3-ml portion of bromine (0.06 mole) was added dropwise, and the reaction was analyzed by gas chromatography. More than 60 percent of the starting material reacted, 10 forming two major products, one of them being 4-bromo-2,6-dimethylphenol. After stirring at 25°C for two hours, the insoluble product was filtered, 5.5 g, and is identified as tetramethylbisphenol A. The carbon tetrachloride solution has 4-bromo-2,6-dimethylphenol 15 as the main component, as identified by gas chromatography and nuclear magnetic resonance, and by comparison with an authentic sample.

The preceding Examples and Comparative Experiments surprisingly indicate that TDDPC compounds having 20 a polymethylene-bridge can be brominated on the aromatic rings, whereas similar compounds having only one linking carbon atom do not ring-brominate.

Example 5 To a slurry of 25 g of brominated bisphenol E 25 (70 percent tribromo, 13 percent tetrabromo, 12 percent dibromo) in 250 ml of epichlorohydrin plus 30 ml of isopropanol at approximately 80°C was added 19.6 g of 50 percent weight/weight NaOH in water over a two-hour period. After the caustic addition, the reaction 30 temperature was maintained at approximately 80°C for 2 33,739A-F hours. After cooling, the reaction mixture was diluted with approximately 200 ml of CH2C12 and was filtered to remove NaCl. Upon evaporation of the CH2C12, the filtrate yielded white crystals.

Additional material was obtained by rotoevaporation of the epichlorohydrin/isopropanol. The total yield of product was 23.8 g (78 percent).

The initial solid has a melting point of 197°C-200°C and an epoxide equivalent weight 10 of 315.9 g. The second solid has a melting point of 171°C-175°C and an epoxide equivalent weight of 309 g. These data, along with nuclear magnetic resonance spectra, suggest that the initial solid is a mixture of tri- and tetrabromotetramethylbis-15 phenol E-diglvcidyl ether, while the second solid is a mixture of di- and tribromotetramethylbisphe-nol E-diglycidyl ether.

Comparative Experiment 3 The diglycidyl ether of tetrabromobis-20 phenol A, 6.00 g (available from The Dow Chemical Company under the name DER 542), was cured with 1.127 g diaminodiphenylsulfone. The cured resin is maintained at 265°C for 1 hour in a convection oven. The resin was observed to lose >50 percent 25 of its weight. ■ Example 6 The first product of Example 5 was employed in the procedure of Comparative Experiment 3 as a replacement for the diglycidyl ether 30 of tetrabromobisphenol A. The resin lost no weight after 1 hour. 33,739A-F 2 7 A comparison of the results of Example 6 and Comparative Experiment 3 indicates that the resin of Example 6 exhibits unexpectedly improved thermal stability. 33,739A-F r 4 r~ o. ! i * • fv J- 4 v s;

Claims (12)

WHAT WE CLAIM IS:

1. A process for the preparation of a compound of the formula wherein n is zero or a positive integer of up to 12, each X independently is Br or H, each R independently is H 3i ~ "* or alkyl of up to 12 carbon atoms, and each R independently is a primary or secondary alkyl moiety of up to 6 carbon atoms, characterized in that (a) a tetraalkyl dihydroxydiaromatic polymethyiene-bridged compound of the formula (III) wherein n is zero or a positive integer of up to 12, each Ra independently is H or alkyl of up to 12 carbon atoms, and each R independently is a primary or secondary alkyl moiety of up to 6 carbon atoms is contacted with a bromination agent in the presence of a reaction - g c~o V - i>j? - 26 - medium and, optionally, a bromination catalyst to form a reaction mixture; (b) the temperature of the reaction mixture is then raised to an elevated temperature until the reaction is completed; and (c) the resulting compound of Formula I is recovered.

2. A process as claimed in Claim 1 characterized in that the brominating agent is bromine.

3- A process as claimed in Claim 1 or Claim 2 characterized in that said reaction medium is methylene chloride, carbon tetrachloride or 1,2-dichloroethane.

4. A process as claimed in any one of Claims 1 to 3 characterized in that step (a) is carried out at the temperature at which the reaction medium is liquid.

5. A process as claimed in any one of Claims 1 to 4 characterized in that the elevated temperature in step (b) is reflux temperature.

6 - A process as claimed in any one of Claim 1 to 5 characterized in that the yield of the desired compound of Formula I is at least 50 mole percent.

7. A process as claimed in any one of Claims 3 to 6 characterized in that said compound of Formula III is 4,4'-(1,2-ethanediyl)bis(2, 6--dimethylphenol), and said reaction medium is carbon tetrachloride or methylene chloride. r -4 >*■' ^ * ' JL < V

3. A compound of the formula: ^ / characterized in that n is zero or a positive integer of uo to 12, each X independently is Br or H with proviso that at least one X is E, each R independently is H or alkyl of up to 12 carbon atoms, and each R independently is a primary or secondary alkyl moiety of up to 5 carbon atoms.

9. A compound of Claim 8 characterized in that each R has up to 3 carbon atoms.

10. a compound of Claim 8 or Claim 5 characterized in that n is zero.

11. A compound of Claim 10 characterized in that at least one X moiety is Br.

12. A compound of Claim 11 characterized in that each R is methyl. ^ ~ '."v C 3 , \ w s i i r. . 3 SEP =909r, • - 28 -