GB1570980A - Aromatic bis-esters and acids - Google Patents

Description

(54) AROMATIC BIS-ESTERS AND ACIDS (71) We, DYNAMIT NOBEL AKTIENGESELLSCHAFT, a German company of 521 Troisdorf bez Kiln, Postfach 1209 Germany (Fed. Rep.), do 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:- This invention relates to aromatic bis-esters and acids which additionally include a bis-ether linkage, and is particularly but not exclusively concerned with such compounds which are halogenated and which are capable of serving as flameproofing agents for plastics materials.

Compounds which contain several functional groups attached to benzene rings have been found to have interesting properties for numerous applications. Thus in cases where polar groups such as ether groups and, in addition, ester groups are present, the property spectrum of the aromatic radical is known to be modified. In cases where the aromatic radicals are additionally substituted by halogen atoms, the compounds can be expected to be suitable for use as flameproofing agents for plastics materials.

According to the present invention there is provided a compound having the general formula

in which each R" independently represents hydrogen or an alkyl radical having up to 6 carbon atoms, W represents a divalent radical of general formula

where Z represents or of general formula

and X independently represents hydrogen, chlorine or bromine, with the proviso that where W represents the divalent radical of general formul (3), at least one of the substituents X of the compound of general formula (1) represents bromine.

Thus included within the scope of the invention are compounds having the general formula

in which each R" independently represents hydrogen or an alkyl radical having up to 6 carbon atoms, X independently represents hydrogen, chlorine or bromine and Z represents CH2 C CH2 or O S O.

Where the nucleus substituents X are bromine or chlorine atoms. and R" is an alkyl radical, these compounds may be termed bis-(alkoxy carbonyl benzyl) ethers of halogenated bisphenols.

Also included within the scope of the invention are compounds having the general formula

in which each R" independently represents hydrogen or an alkyl radical having up to 6 carbon atoms and X independently represents hydrogen, chlorine or bromine, with at least one X representing bromine. When R" represents an alkyl radical, such compounds may be termed bis-(carbalkoxy-phenoxy methyl) benzenes.

It is preferred that in formulae (1), (4) and (5) given above, the terminal phenylene groups are para-substituted, although of course theCOOR" groups may alternatively be in the ortho- or meta-position.

When the above-defined compounds are esters, i.e. when R" is an alkyl radical, it is preferred that the alkyl radical contains from 1 to 4 carbon atoms. For example it may be a methyl, ethyl, n-propyl or i-propyl radical. Preferably the compounds are dimethyl esters.

With regard to the compounds of general formula (4) above, i.e. those compounds of general formula (1) in which W is the divalent radical of general formula (2), the four substituents X may with advantage be four bromine substituents, four chlorine substituents or four hydrogen substituents, although compounds containing both chlorine and also bromine atoms, obtainable for example by the chlorobromination of bisphenol A, are also possible, compounds with a predominant number of bromine atoms being preferred. For example of the four substituents X, from 0 to 1 may be chlorine and from 4 to 3 may be bromine.

Similarly, with regard to the four eligible substituents of the central nucleus of formula (3) or (5), these may with advantage be four bromine atoms. Alternatively each of these substituents X may represent a chlorine atom. Also preferred are the cases where the central nucleus carries four hydrogen substituents or alternatively four substituents consisting partly of bromine and partly of chlorine. High contents of from 4.0 to 2.8, more preferably from 3.9 to 2.8 atoms of bromine and from 0 to 1.2 more preferably from 0.1 to 1.2 atoms of chlorine are preferred. Thus as with the compounds corresponding to general formulae (2) and (4), there may be from 0 to 1 chlorine atoms and from 4 to 3 bromine atoms. However, it is also possible for 1 to 3 bromine substituents or even up to three chlorine substituents to be present in addition to hydrogen.

The substituents of the two terminal aromatic nuclei of formula (1) where W represents the radical of formula (3), or of formula (5), are preferably four hydrogens, or two halogens and two hydrogens, or four halogens. The preferred halogens are again bromine or a predominant content of bromine, for example from 70 to 99 mole Vn, and more especially 85 mole % or more of bromine, with the remainder being chlorine.

According to another aspect of the invention there is provided a process for producing an ester compound of general formula (4) which comprises reacting a salt having an anion of general formula

and a halomethyl alkyl benzoate of general formula

in which Y represents a halogen atom, in the presence of a solvent for the reactants, to form the desired ester compound.

Preferably the salt is formed in situ by reacting an alkali hydroxide and the corresponding bisphenol A compound or dihydroxy diphenyl sulphone compound.

According to yet another aspect of the invention there is provided a process for producing an ester compound of general formula (5) which comprises reacting a phenolate of general formula

and a halomethyl compound of general formula

in which Y represents a halogen atom and in which at least one of the substituents X of the phenolate or halomethyl compound represents bromine, in the presence of a solvent for the reactants, to form the desired ester compound.

Again, it is preferred that the phenolate is formed in situ by reacting an alkali hydroxide and the corresponding hydroxy benzoic acid alkyl ester.

In formulae (7) and (9) above, the atom Y preferably represents chlorine for economic reasons although, for example the corresponding bromo compounds may be used. The halomethyl groups may be in the ortho- or meta or para-positions on the nucleus.

In the case where the ester produced has a small chlorine content on the central nucleus this may emanate from a bromine-chlorine exchange during the production process or during production of, for example, the tetrabromoxylylene dichloride obtainable as intermediate stage by the side-chain chlorination of tetrabromoxylene or, in cases where the nuclear halogen has been introduced by bromochlorination during production of the intermediate stage, even from the use of a bromine which contains chlorine.

Solvents which are preferably used in the process according to the invention are those in which the alkali hydroxide, for example sodium hydroxide, and also the bisphenols or sulphones or their salts, or the hydroxy esters or their phenolates can be adequately dissolved. Solvents such as these preferably have boiling points above 90"C, more preferably above 1000 C, and are preferably used in admixture with water. It is also possible to use solvents with a lower boiling point. In this case, it is advisable to work under pressure. For example the solvent used may be ethylene glycol monomethyl ether (referred to hereinafter as methyl glycol), dioxane, methylisobutyl ketone or methylethyl ketone.

When present, the quantity of water included in the solvent is not critical.

Depending upon the solubility of the substances to be dissolved, the quantity may be, for example, up to 65%, and more preferably to 25%.

When the salt or phenolate is prepared in situ, the preferred alkali hydroxide is sodium hydroxide, although potassium hydroxide and other hydroxides may also be used. The hydroxides may be added to the reaction mixture in the form of an aqueous solution. The alkali hydroxide is preferably used in a quantity equivalent to the bisphenol, sulphone or hydroxy ester because an excess generally gives rise to secondary reactions with the halomethyl group(s) of the other reaction component.

The temperature at which the process is carried out is preferably in the range from 40 to 1 500C and more preferably in the range from 60 to 1300 C. For the "in situ" reaction a temperature suitable for producing the salt or phenolate of from room temperature to 500C is preferably maintained at the beginning of the reaction. In order to complete the reaction, it is preferred to work at temperatures of from 70"C up to the boiling point of the solvent.

The esters produced in accordance with the above procedures generally precipitate in pure form either during the reaction, e.g. at the boiling temperature of the reaction mixture, or on cooling of the reaction mixture. They may be further purified by washing with water until they are free from halide e.g. chloride, or by crystallisation from one of the numerous solvents which may be used.

The acid compounds having the general formula (4) and (5) in which R" represents hydrogen may be produced in accordance with the invention by hydrolysing the respective corresponding ester compound.

The ester compounds according to the invention have comparatively high melting points of from about 160"C up to 2500C and higher, especially in the case of the symmetrical aromatic halogen compounds, which is unusual for compounds containing several ether bonds and ester bonds. In addition, the compounds show a decidedly stretched molecular structure which is particularly pronounced in the derivatives of the p-halo methyl benzoic acid esters. These properties have proved to be particularly valuable for the use of the halogenated compounds as flameproofing agents.

According to a still further aspect of the invention there is provided a composition comprising a plastics material and, as flameproofing agent therefor, a halogen-containing acid or ester compound of general formula (4) or (5).

The processing of all kinds of plastics materials containing these compounds as flameproofing agents, but especially thermoplastic processing in extruders, has proved to be greatly facilitated because the compounds according to the invention do not generally show any signs of decomposing at the processing temperatures applied. Compositions including such compounds as flameproofing agents surprisingly show hardly any migration of the flameproofing agents during prolonged storage under heat.

It has been found that in numerous groups of plastics materials, the addition of the halogenated compounds according to the invention reduces inflammability and promotes largely self-extinguishing properties. Examples of plastics materials which may be used are polyolefins such as polyethylene and polypropylene, polyesters such as polyethylene terephthalates and polybutylene terephthalates, unsaturated polyesters, polystyrene, styrene copolymers, and polycarbonates.

The halogenated compounds are preferably included in the compositions in amounts of from 2 to 20% by weight. In addition, synergistically acting antimony compounds, such as Sb2O3, may also be included for enhancing the flameproofing effect.

The compounds according to the invention may also be used as organic intermediate products, numerous reactions being possible both by virtue of the acid or ester group and also by virtue of the halogen atoms. In particular, the acids and esters may be used as dicarboxylic acid components of certain polyesters. Our copending British patent application 44087/76, (Serial No. 1570979), from which this application is divided, describes and claims a polyester containing structural units of the formula

in which R' represents an alkylene radical (as defined in the specification of that application) having from 2 to 10 carbon atoms, a cycloalkylene radical or a divalent radical derived from a hydroxyl group-terminated oligomeric alkylene t rephathalate, and in which the divalent radicals R include (a) radicals having the general formula

wherein X independently represents hydrogen, bromine or chlorine and Z represents CH3-C-CH3 or O S O, and, optionally, (b) radicals which are unsaturated, with the proviso that in the case where R does not include unsaturated radicals at least one of the substituents X of general formula (15) represents bromine.

Also described and claimed is a process for producing such a polyester which comprises condensing (i) a dicarboxylic acid component comprising (a) a saturated dicarboxylic acid of formula HOOC-R-COOH (12) or an ester forming derivative of such a saturated dicarboxylic acid, and, optionally, (b) an unsaturated dicarboxylic acid or ester forming derivative thereof, and (ii) a dihydric alcohol component comprising a saturated alcohol of formula HO-R'-OH (13), to form the desired polyester.

The following Examples illustrate the invention.

Example 1 Production of tetrabromobisphenol-A-bis-(4-methoxy carbonylbenzyl) ether (general formula (4))

In a 6 litre three-necked flask equipped with a reflux condenser, stirrer and thermometer, a solution of 120 g (3 moles) of sodium hydroxide in 120 ml of water was added with stirring to 3.5 litres of ethylene glycol monomethyl ether (b.p. 122 126"C)--hereinafter referred to as methyl glycol-and 816 g (1.5 moles) of tetrabromobisphenol A. The addition was accompanied by spontaneous heating. A clear solution of the sodium salt of the bisphenol was obtained and 554 g (3 moles) of p-chloromethyl benzoic acid methyl ester were stirred into this solution at about 40"C. The reaction mixture was then boiled under reflux with stirring for 2 hours.

At an internal temperature upwards of about 80"C, the reaction mixture became cloudy through the precipitation of sodium chloride.

At the end of the boiling period, the reaction mixture was cooled to room temperature. The bis-ether/bis-ester of the above formula crystallised out in colourless form. It was filtered off under suction, washed with a little cold methyl glycol, stirred up in water to remove sodium chloride and then filtered under suction again, followed by washing with water until the filtrate was free of chloride.

Yield after drying: 1160 g, corresponding to 92%. M.p.: 155--158.50C.

15 g of the substance recrystallised from 45 ml of boiling xylene produced the crystalline melting at 157.5-1600C.

Elemental analysis: C33H28Br4O6 (840.23) Calculated: C 47.17%; H 3.36 /"; Br 38.04%; 0 11.42% Observed: C 47.15%; H 3.42%; Br 37.89%; 0 11.25 /,,.

EXAMPLE 2 Production of tetrachlorobisphenol-A-bis-(4-methoxycarbonylbenzene) ether (general formula (4))

Following the procedure of Example 1, 800 ml of substantially anhydrous methyl glycol, 32 g (0.8 mole) of sodium hydroxide dissolved in 40 ml of water, 146.4 g (0.4 mole) of tetrachlorobisphenol A and 147.7 g (0.8 mole) of pchloromethyl benzoic acid methyl ester were reacted in a 2-litre three-necked flask equipped in the same way as that used in Example 1. A colourless deposit, which increased in volume as the reaction progressed, was precipitated from the previously clear reaction mixture at about 110"C. After boiling under reflux for 1.5 hours, the reaction mixture was cooled and the undissolved substance filtered off under suction. In order to remove sodium chloride, the filter cake was suspended in water, filtered under suction again and washed with water until free from chloride ions. The water-moist product was washed with a little methanol and dried in a recirculating air cabinet at 80 to 900 C.

Yield 228 g corresponding to 86.1% of colourless bis-ether/bis-ester, m.p.: 152--158"C. M.p. after recrystallisation from ethylacetate in a ratio of 1:9 was 159-161.5 C.

Elemental analysis: C33H28CI406 (662.40) Calculated: C 59.84%; H 4.260/,; Cl 21.41%; 0 14.49% Observed: C 59.91%; H 4.32%; Cl 21.50%: 0 14.31%.

EXAMPLE 3 Production of tetrabromo-4,4'-dihydroxydiphenyl sulphone-bis-(4 methoxycarbonylbenzyl)-ether (general formula (4))

Following the procedure of Eample 1, 410 g (0.725 mole) of tetrabromo-4,4'dihydroxydiphenyl sulphone, 58 g (1.45 mole) of sodium hydroxide in 60 ml of water and 268 g (1.45 mole) of p-chloromethyl benzoic acid methyl ester were reacted in 2 litres of methyl glycol (b.p. 1 17-1220C) in a 4 litre three-necked flask, the reaction mixture being boiled under reflux with stirring for 1.5 hours. The reaction began 10 minutes after boiling temperature had been reached and the contents of the flask became increasingly thicker as a result of material which precipitated. The reaction mixture was then filtered under suction at room temperature and worked up in the same way as described in Example 2. Yield after drying: 561 g (89.6 ' of the theoretical), m.p.: 233-2380C.

A sample was recrystallised twice from dioxane in a ratio of 1:10. M.p. after recrystallisation: 238-241 0C.

Elemental analysis: Ca0H2zBr4OsS (862.22) Calculated: C 41.79; H 2.57%; Br 37.07%; 0 14.85%; S 3.72 /" Observed: C 42.01%; H 2.66%; Br 36.94%; 0 14.72%; S 3.88%.

EXAMPLE 4 Production of 4,4'-dihydroxydiphenyl sulphone-bis-(4 methoxycarbonylbenzyl)-ether (general formula (4))

Following the procedure of Example 3, 1000 ml of methyl glycol (b.p. 122126 C), 125.2 g (0.5 mole) of 4,4'-sulphonyl diphenol, 56 g (I mole) of potassium hydroxide in 60 ml of water and 184.6 g (I mole) of p-chloromethyl benzoic acid methyl ester were reacted in a 2 litre reaction vessel. After boiling under reflux for 1.5 hours, during which time potassium chloride was precipitated at internal temperatures of 80 C and above, the reaction mixture was cooled to OOC. The solids which had crystallised out were filtered off under suction, washed with water until free from KCl and dried. Yield: 227 g (83% of the theoretical), m.p.: 145 1550C. Recrystallisation from dioxane in a ratio of 1:5 gave the pure substance with a melting point of 161-163 C.

Elemental analysis: C30H2sO8S (546.6) Calculated: C 65.92%; H 4.79%; 0 23.42%; S 5.87% Observed: C 65.77%; H 4.72%; 0 23.54%; S 5.94%.

EXAMPLE 5 Production of tetrabromobisphenol-A-bis-(4-ethoxycarbonylbenzyl ether (general formula (4))

Following the procedure of Example 1, the above ethyl ester was synethesised in a 2 litre flask from 900 ml of methyl glycol (b.p. 117-122 C), 163.2 g (0.3 mole) of tetrabromo-bisphenol A, 24 g (0.6 mole) of sodium hydroxide in 24 ml of water and 238.5 g (0.6 mole) of p-chloromethyl benzoic acid ethyl ester, the reaction mixture being boiled under reflux for 1.5 hours. Sodium chloride was formed at internal temperatures of 900C and above. This ester only crystallised completely from the reaction mixture at a temperature of from -15 C to -200C. Yield: 241 g (92% of the theoretical), m.p.: 117--1230C. M.p. after recrystallisation from petrol (b.p. 80-100 C) in a ratio of 1:15 was 121-123 C.

Elemental analysis: C35H32Br4Oe (868.28) Calculated: C 48.42%; H 3.71%; Br 36.81%; O 11.06% Observed: C 48.64%; H 3.66%; Br 36.95%; O 11.14%.

EXAMPLE 6 Tetrabromobisphenol-A-bis-(4-butoxycarbonylbenzyl) ether (general formula (4))

Following the procedure described in Example 1, 800 ml of methyl glycol (b.p.

117--122"C), 163.2 g (0.3 mole) of tetrabromobisphenol A, 24 g (0.6 mole) of sodium hydroxide in 24 ml of water and 136 g (0.6 mole) of p-chloromethyl (benzoic acid-n-butyl ester) were reacted in a 2-litre three-necked flask. The mixture was boiled under reflux for 1.5 hours and then left standing overnight at -200C to crystallise out, followed by working up in the same way as in Example 1.

Yield: 228 g (82% of the theoretical), m.p.: 8890C. Recrystallisation from nbutanol in a ratio of 1:30 gave colourless needles melting at 91--93.50C.

Elemental analysis: C39H40Br406 (924.4) Calculated: C 50.67%; H 4.36 ,; Br 34.58%; 0 10.38% Observed: C 50.820/,; H 4.25%; Br 34.71%; 0 10.44%.

EXAMPLE 7 Production of tetrabromobisphenol-A-bis-(3-methoxycarbonylbenzyl) ether (general formula (4))

Following the procedure of Example 6, 900 ml of methyl glycol (b.p. 122 126"C), 217.6 g (0.4 mole) of tetrabromobisphenol A, 32 g (0.8 mole) of sodium hydroxide in 40 ml of water and 147.4 g (0.8 mole) of m-chloromethyl benzoic acid methyl ester were reacted by the process according to the invention. The precipitation of sodium chloride began at temperatures of 85"C and above, whilst the bis-ether/bis-ester, formed after boiling under reflux for 1.5 hours, remained in solution. It was precipitated by cooling to -200C and isolated in known manner.

Yield: 245 g (73% of the theoretical), m.p.: 101--1080C. M.p. after recrystallisation from petrol (80--100"C) in a ratio of 1:40 was 116--119"C.

Elemental analysis: C33H28Br406 (840.23) Calculated: C 47.17%; H 3.36%; Br 38.04%; 0 11.42% Observed: C 47.31%; H 3.24%; Br 38.19%; 0 11.56%.

EXAMPLE 8 Production of 1,4-bis-(p-methoxycarbonyl-phenoxymethyl 2,3,5,6-tetrabromobenzene (general formula (5))

In a 6 litre flask equipped with a stirrer, reflux condenser and thermometer, 608.6 g (4 moles) of 4-hydroxy benzoic acid methyl ester were suspended in 3.5 litres of methyl glycol and converted into a solution of the phenolate by the addition of 160 g (4 moles) of sodium hydroxide in 160 ml of water. 981.3 g (2 moles) of 1 ,4-bis-(chloromethyl)-2,3,5,6-tetrabromobenzene were then introduced with stirring at about 35 to 400 C, after which the reaction mixture was quickly heated with stirring to boiling temperature. A reaction occurred when an internal temperature of about 90 C had been reached, being accompanied by the precipitation of a colourless, voluminous deposit. The reaction mixture, which at first became increasingly thicker, became more thinly liquid again at boiling temperature. After boiling under reflux for 1.5 hours, the reaction mixture was cooled to room temperature; the deposit was filtered off under suction, washed with water until free from sodium chloride and then dried.

The above ester was obtained in a yield of 1276 g, corresponding to 88.3% M.p.: 263--271"C, 5 g of product recrystallised from 250 ml of xylene produced the pure substance melting at 272-2750C.

Elemental analysis: C24H1aBr4O6 (722.05) Calculated: C 39.92%; H 2.51%; Br 44.27%; 0 13.30% Observed: C 40.21; H 2.66%; Br 43.98%; 0 13.19%.

EXAMPLE 9 Production of 1,3-bis-(p-methoxycarbonyl-phenoxymethyl)-2,4,5,6-tetrahalogen benzene (general formula (5); x+y=4)

Following the procedure of Example 8, 200 ml of methyl glycol (b.p. 122126 C), 30.4 g (0.2 mole) of 4-hydroxy benzoic acid methyl ester, 8 g (0.2 mole) of sodium hydroxide in 8 ml of water and 49 g (0.1 mole) of l,3-bis-(chloromethyl)- 2,4,5,6-tetrahalogen benzene were reacted in a 250 ml three-necked flask. The 1,3bis-(chloromethyl)-tetrahalogen benzene which was used was the product obtained by side chain chlorination of tetrabromo-m-xylene; it contained bromine and a little chlorine in the nucleus as a result of Cl/Br exchange.

The mixture was boiled under reflux with stirring for 1.5 hours, resulting in the precipitation of sodium chloride, with the bis-ether/bis-ester of the above formula remaining in solution at boiling temperature. On cooling of the reaction mixture, the required bis-ester product crystallised out at internal temperatures of 100 C and below. On reaching room temperature, the product was filtered off under suction, washed with water until free from sodium chloride and the colourless crystallisate was dried. The yield was 61 g, corresponding to 84% of the theoretical.

M.p.: 167-1740C. M.p. after recrystallisation from methoxyethyl chloride: 174- 176 C.

Elemental analysis: C24H18Br3.sCI0sO6 (699.82) Calculated: C 41.18%; H 2.59%; Br 39.97%; Cl 2.53%; 0 13.72% Observed: C 41.31%; H 2.54%; Br 39.90; Cl 2.60%; 0 13.49%.

EXAMPLE 10 Production of 1,2-bis-(p-methoxycarbonyl-phenoxymethyl)-3,4,5,6-tetrahalogen benzene (general formula (5); x+y=4)

350 ml of methyl glycol (b.p. 122-126 C), 30.43 g (0.2 mole) of 4-hydroxy benzoic acid methyl ester, 8 g (0.2 mole of sodium hydroxide in 8 ml of water and 49 g (0.1 mole) of bromine-containing 1,2-bis-(chloromethyl)-3,4,5,6-tetrahalogen benzene, were reacted with stirring for 1.5 hours at the boiling temperature of the mixture in a 500 ml flask in the same way as described in Example 9. The reaction began at about 500C and the bis-ether/bis-ester which formed precipitated in the form of a colourless deposit. It was isolated and worked up in the same way as described in Example 9. Yield: 57.3 g (79.5% of the theoretical); m.p.: 199-204 C.

Recrystallisation from methyl glycol in a ratio of 1:24 produced a pure crystalline melting at 205 to 207 C.

Elemental analysis: C24H1BBr3Cl0906 (682) Calculated: C 42.26%; H 2.66%; Br 36.32%; Cl 4.68%; 0 14.07% Observed: C 42.49%; H 2.71%; Br 36.14%; Cl 4.81%; 0 13.95%. t EXAMPLE 11 Production of 1,3-bis-(4-methoxycarbonyl 2,6-dichlorophenoxymethyl)-2,4,5,6- tetrabromobenzene (general formula (5))

Following the procedure of Example 8, 3 litres of methyl glycol (b.p. 122126 C), 221 g (1 mole) of 3,5-dichloro-4-hydroxy benzoic acid methyl ester, 40 g (1 mole) of sodium hydroxide in 40 ml of water and 289.8 g (0.5 mole) of 1,3-bis (bromomethyl)-2,4,5,6-tetrabromobenzene were reacted in a 4 litre reaction vessel and the reaction product worked up as in Example 8. The reaction began at temperature of 95 C and above and was accompanied by the formation of a colourless voluminous deposit. Reaction time: 1.5 hours with stirring at reflux temperature. Yield: 362 g (84.2% of the theoretical), m.p.: 253-2580C. 10 g recrystallised from 300 ml of 1,2-dibromoethane produced the pure bis-ester/bisether of the above formula, m.p.: 266-2680C.

Elemental analysis: C24H14Br4Cl4O6 (859.83) Calculated: C 33.53%; H 1.64%; Br 37.17%; Cl 16.49%; 0 11.17% Observed: C 33.68%; H 1.53%; Br 37.02%; Cl 16.60%; 0 11.28%.

EXAMPLE 12 Production of 1,4-bis-(4-methoxycarbonyl-2,6-dibromophenoxymethyl) 2,3,5,6-tetrabromobenzene (general formula (5))

As in Example 11, the following substances were reacted by the process according to the invention: 600 ml of methyl glycol (b.p. 122--1260C), 37.2 g (0.12 mole) of 3,5-dibromo-4-hydroxy benzoic acid methyl ester, 4.8 g (0.12 mole) of sodium hydroxide in 5 ml of water and 34.8 g (0.06 mole) of l,4-bis-(bromomethyl)- 2,3,5,6-tetrabromobenzene.

The reaction began at about 70--75"C, the reaction mixture being boiled under reflux for 1.5 hours. The desired product was precipitated at internal temperatures of 110 C and above. Yield: 52.5 g (84.2% of the theoretical), m.p.: 297--301"C. 25 g recrystallised from 900 ml of 1,2-dibromoethane gave a pure crystallisate melting at 302-304 C.

Elemental analysis: C24H,4Br806 (1037.65) Calculated: C 27.78%; H 1.36%; Br 61.61%; 0 9.25% Observed: C 27.66%; H 1.29%; Br 61.80%; 0 9.29%.

Claims (43)

WHAT WE CLAIM IS:

1. A compound having the general formula

in which each R" independently represents hydrogen or an alkyl radical having up to 6 carbon atoms, W represents a divalent radical of general formula

where Z represents CH3 C CH3 or O S O or of general formula and X independently represents hydrogen, chlorine or bromine, with the proviso that where W represents the divalent radical of general formula (3), at least one of the substituents X of the compound of general formula (1) represents bromine.

2. A compound having the general formula

in which each R" independently represents hydrogen or an alkyl radical having up to 6 carbon atoms, X independently represents hydrogen, chlorine or bromine and Z represents CH3-C-CH3 or O=S=O.

3. A compound having the general formula

in which each R" independently represents hydrogen or an alkyl radical having up to 6 carbon atoms and X independently represents hydrogen, chlorine or bromine, with at least one X representing bromine.

4. A compound according to claim 1, 2 or 3 wherein the terminal phenylene groups of general formula (1), (4) or (5) are para substituted.

5. A compound according to any one of the preceding claims wherein in general formula (1), (4) or (5) each R" independently represents an alkyl radical having up to 6 carbon atoms.

6. A compound according to any one of the preceding claims wherein each R" independently represents an alkyl radical having up to 4 carbon atoms.

7. A compound according to claim 6 wherein R" represents a methyl or ethyl radical.

8. A compound according to any one of the preceding claims wherein each X of formula (2), (3) or (4) or each X of the central nucleus of formula (5) represents a bromine atom.

9. A compound according to any one of claims 1 to 7 wherein each X of formula (2), (3) or (4), or each X of the central nucleus of formula (5) represents a chlorine atom.

10. A compound according to claim 1 or 3 or any one of claims 4 to 7 when appendant thereto wherein the four substituents X of the nucleus of formula (3) or the central nucleus of formula (5) include both bromine and chlorine atoms.

11. A compound according to claim 1 or 3 or any one of claims 4 to 7 when appendant thereto wherein the four substituents X of the nucleus of formula (3) or the central nucleus of formula (5) include an average from 4.0 to 2.8 bromine atoms and from 0 to 1.2 chlorine atoms.

12. A compound according to claim 11 wherein the four substituents X of the nucleus of formula (3) or the central nucleus of formula/5) include on average from 2.8 to 3.9 bromine atoms and from 1.2 to 0.1 chlorine atoms.

13. A compound according to claim 1 in which W represents a divalent radical of general formula (3), or claim 3, or any one of claims 4 to 12 when appendant to claim 1 or 3, wherein the two terminal nuclei of general formula (1) or (5) each carry four halogen atoms which may be bromine or chlorine.

14. A compound according to claim 13 wherein the two terminal nuclei carry two halogen atoms which may be bromine or chlorine and two hydrogen atoms.

15. A compound according to claim 13 or 14 wherein the halogen atoms which may be bromine or chlorine are all bromine atoms.

16. A compound according to claim 1 substantially as described in any one of Examples 1 to 7.

17. A compound according to claim 1 substantially as described in any one of Examples 8 to 12.

18. a process for producing an ester compound having the general formula (4) as set out and defined in claim 2 or any one of claims 4 to 9 when appendant to claim 2, but wherein each R" represents an alkyl radical having up to 6 carbon atoms, which process comprises reacting a salt having an anion of general formula

and a halomethyl alkyl benzoate of general formula

in which Y represents a halogen atom, in the presence of a solvent for the reactants, to form the desired ester compound.

19. A process according to claim 18 wherein the salt is formed in sftu by reacting an alkali hydroxide and the corresponding bisphenol A compound or dihydroxy diphenyl sulphone compound.

20. A process for producing an ester compound having the general formula (5) as set out and defined in claim 3 or any one of claims 4 to 15 when appendant to claim 3, but wherein R" represents an alkyl radical having up to 6 carbon atoms, which process comprises reacting a phenolate of general formula

and a halomethyl compound of general formula

in which Y represents a halogen atom and in which at least one of the substituents X of the phenolate or the halomethyl compound represents bromine, in the presence of a solvent for the reactants, to form the desired ester compound.

21. A process according to claim 20 wherein the phenolate is formed in situ by reacting an alkali hydroxide and the corresponding hydroxy benzoic acid alkyl ester.

22. A process according to claim 19 or 21 wherein the salt or phenolate is formed in situ at a temperature of up to 500 C.

23. A process according to any one of claims 18 to 22 wherein Y represents a chlorine atom.

24. A process according to any one of claims 18 to 23 wherein the reaction is performed at a temperature of from 40 to 1500C.

25. A process according to claim 24 wherein the reaction is performed at a temperature of from 60 to 1300C.

26. A process according to any one of claims 18 to 25 wherein the solvent comprises ethylene glycol monomethyl ether, dioxane, methyl isobutyl ketone or methyl ethyl ketone.

27. A process according to any one of claims 18 to 26 wherein the solvent includes water.

28. A process according to claim 27 wherein the solvent includes up to 65% of water.

29. A process according to claim 28 wherein the solvent contains up to 25% of water.

30. A process according to claim 18 substantially as described in any one of Examples 1 to 7.

31. An ester compound of general formula (4) whenever produced by the process according to claim 18, 19 or 30 or any one of claims 22 to 29 when appendant to claim 18 or 19.

32. A process according to claim 20 substantially as described in any one of Examples 8 to 12.

33. An ester compound of general formula (5) whenever produced by the process according to claim 20, 21 or 32, or any one of claims 22 to 29 when appendant to claim 20 or 21.

34. A process for producing an acid compound having the general formula (4) as set out and defined in claim 2 but wherein R" represents hydrogen, which process comprises hydrolysing an ester compound of general formula (4) as set out and defined in claim 2 wherein R" represents an alky radical having up to 6 carbon atoms, or an ester compound according to claim 31, to form the desired acid compound.

35. An acid compound of general formula (4) whenever produced by the process according to claim 34.

36. A process for producing an acid compound having the general formula (5) as set out and defined in claim 3 but wherein R" represents hydrogen, which process comprises hydrolysing an ester compound of general formula (5) as set out and defined in claim 3 wherein R" represents an alkyl radical having up to 6 carbon atoms, or an ester compound according to claim 33, to form the desired acid compound.

37. An acid compound of general formula (5) whenever produced by the process according to claim 36.

38. A composition comprising a plastics material and, as flameproofing agent therefor, a halogen-containing acid or ester compound according to any one of claims 1 to 17, 31, 33, 35 or 37.

39. A composition according to claim 38 wherein the plastics material comprises a polyolefin, a saturated or unsaturated polyester, a polystyrene, a polycarbonate or a styrene copolymer.

40. A composition according to claim 38 or 39 which contains from 2 to 20% by weight of the compound.

41. A composition according to claim 38, 39 or 40 which additionally includes a synergistically acting antimony compound.

42. A composition according to claim 41 wherein the antimony compound is antimony trioxide.

43. A composition according to claim 38 substantially as hereinbefore described.