AU617337B2

AU617337B2 - Process for preparing halogenated imides and their application as flame-retardant agents

Info

Publication number: AU617337B2
Application number: AU19731/88A
Authority: AU
Inventors: Evelyne Bonnet; Bernard Gurtner
Original assignee: Atochem SA
Current assignee: Arkema France SA
Priority date: 1987-07-24
Filing date: 1988-07-22
Publication date: 1991-11-28
Anticipated expiration: 2008-07-22
Also published as: DK412988A; JPH06228365A; JPH0768407B2; KR890002282A; DK24795A; NO173650C; IL86673A0; DK412988D0; NO883003L; SG70567A1; NO173650B; FI883475A0; FI92390C; KR0130475B1; NO883003D0; FI92390B; EP0300879B1; IL86673A; ZA884650B; DK170772B1

Abstract

Preparation of halogenated imides derived from hydrazine and halogenated dicarboxylic acid anhydride and capable of being employed as flame-retardant agents for plastics. The condensation of hydrazine and of halogenated dicarboxylic acid anhydride is carried out in aqueous medium at a temperature ranging from 40 to 225 DEG C with an anhydride/hydrazine molar ratio lower than 2.

Description

617 337mi COMMONWEALTH OF AUSTRALIA PATENTS ACT 1952-60 COMPLETE SPECIFICATION

(ORIGINAL)

Class Application Number Lodged: 9 J o Complete Specification Lodged: A- +.4 int. Class Priority: ,Related Art: Published: 9* 9 9 9 Name of Applicant:

ATOCH-EM

9 0 raAddress of Applicant: .00 0 Actual Inventor: Address for Service La Defense 10 4 8, Cours Michelet 92800 Puteaux, France EVELYNE BONNET and BERNARD GtJRTNER EDWD. WATERS SONS, 50 QUEEN STREET, MELBOURNE, AUSTRALIA, 3000.

Complete Specification for the invention entitled: PROCESS FOR PREPARING HALOGENATED IMIDES AND THEIR APPLICATION AS FLAME-RETARDANT AGENTS The following statement is a full description of this invention, including the best method of performing it known to r 311 -U l~ .~Lnlf=ii~i3 1C PROCESS FOR PREPARING HALOGENATED IMIDES AND THEIR APPLICATION AS FLAME-RETARDANT AGENTS The present invention relates to the synthesis of polyhaloimides, and more especially to that of imides derived from halogenated dicarboxylic acids such as tetraa I o, bromophthalic acid.

0 0 Polyhaloimides, in particular tetrabromophthalimides and bis(tetrabromophthalimides), are well known compounds which find application as flame retardants in many inflammable materials, especially in plastics [see, S for example, the paper by S.M. SPATZ et al, entitled «4 "Some N-substituted tetrabromophthalimide fire-retardant additives", in Industrial and Engineering Chemistry Product Research and Development, vol. 8, no. 4 (1969) pages 397-398, as well as patents US 3,873,567 and FR 2,369,261 S, and applications JP 74-045062 and 75-0643773.

O o However, the preparation processes described in the references cited above give indifferent yields and lead to products which very frequently contain substances that are volatile at the temperatures of use in some poly- A meric materials, and cause corrosion of moulds. In addition, the use, for their preparation, of organic solvents, in particular, (xylene, toluene, alcohol and acetic acid), most frequently selected on the basis of their capacity to form azeotropic mixtures with water, enabling the water of condensation produced by the imidation reaction to be carried away, or their capacity to dissolve the halogenated -2dicarboxylic acid anhydride, necessitates costly operations for separation and recovery of these solvents, as well as means of drying suitable for thu removal of organic solvent vapours.

The abovementioned disadvantages are to be found, *s 0 oa in particular, in the case of polyhaloimides derived from hydrazine and halogenated dicarboxylic acid anhydrides.

It has now been found that it is not essential to use an I ooo organic solvent in order to dissolve the anhydride and/or remove the water of condensation, and that, by working in o* aqueous medium under certain conditions, it is possible o* to obtain, in very high yields and without problems of disio, charge of effluents and environmental problems, products which, without prior purification, are entirely suitable for the flameproofing of macromolecular substances, inb0 cluding those of which use is made at high temperature, especially above 2500C.

The process according to the invention, which consists in condensing hydrazine with a halogenaged dicarboxylic acid anhydride, is characterized in that the reaction is performed in aqueous medium, at a temperature ranging from 40 to 225 0 C, with a mole ratio anhydride/hydrazine of less than 2.

Among halogenated anhydrides which are usable, the following may be mentioned more especially: anhydrides of aromatic (benzene, naphthalene, anthracene) dicarboxylic acids, in particular those of c -i 2*I general formula: n in which X denotes a bromine or chlorine atom, m is an S o, integer ranging from 2 to 4, and n and p are integers o f 5 ranging from 0 to 2; and anhydrides of cycloaliphatic dicarboxylic acids, such as 1,4,5,6,7,7-hexabromobicycloC2.2.13hept-5-ene- 2,3-dicarboxylic acid anc its chlorinated homolog (chlor- S endic acid), corresponding to the formula: hi x (II 0 in which X has the same meaning as above. Bromophthalic anhydrides, for example 3,4- (or 3,6- or thalic anhydride, 3,4,6-tribromophthalic anhydride and more especially tetrabromophthalic anhydride, are preferably used.

According to the present invention, it is possible to use a single anhydride or a mixture of two or more anhydrides. Commercial anhydrides, often containing a small amount of inorganic acids, may be used as such without prior purification. It has been found, in effect, that especially good results are obtained when the aqueous dispersion or solution of anhydride employed is acidic or strongly acidic (pH less than 7).

4 The amount of water forming the reaction medium of the process according to the invention can vary within wide Limits, the only condition being that it is sufficient to provide for appropriate dispersion of the reactants and to permit good agitation. This condition is generally fulfilled by using an amount of water such that a the content of solid substances in the reaction medium is between approximately 5 and 75% by weight, preferably between 20 and 9 9 The reaction may be performed at atmospheric preso sure at a temperature ranging from 40 to 1000C or, on condition that it is performed under pressure, at a higher temperature which can range up to 225 0 C. It is preferable to work at between 100 and 225 0 C, which corresponds to pressures of between 1 and 25 bars approximately.

9 Hydrazine in the form of a hydrate or hydrazinium 9 0 salt (for example sulphate, hydrohalide, acetate) may be used as such or in the form of a dilute aqueous solution.

Preferably, hydrazine hydrate is used in the form of a commercial aqueous solution. The process according to the invention is advantageously carried out by gradually introducing hydrazine into the solution or dispersion of halogenated anhydride, previously heated and maintained with stirring.

The reaction time can vary within wide Limits, but is generally between 1 and 20 hours. After the reaction medium is cooled, the solid suspension obtained is EIILP~-X- i I- filtered and optionally washed with water to neutrality, and the product is then dried by traditional means of drying.

The mole ratio anhydride/hydrazine can assume various values. If a mole ratio 4i-t-h-e-v-ci-e4i-t-y--f- 2 and S" a temperature at least equal to 140 0 C are used, the pro- 0 0o 0a duct obtained generally consists of the bis-(imide) a 4 0040 corresponding to the following general structure: SC C A N

N

S" 0 in which A denotes the residue of the halogenated anhydride employed.

At lower temperatures, the product obtained con- 09 0 0 tains, in addition to the bis(imide) of formula (III), 0oo a variable proportion, which can reach 80% by weight, of a substantially equimolar mixture of the starting halogenated anhydride and the corresponding N-aminoimide of general structure: 0 N NH (IV) 0 where A has the same meaning as above, it being possible for this N-aminoimide to be in salt form (sulphate, hydrohalide, acetate). The content of bis(imide) (III) in the product obtained generally increases proportionately as 6 the reaction temperature approaches 140 0 C or above.

When a ratio of Less than 1 or in the vicinity of 1 is used, the product chiefly obtained is the N-aminoimide of general structure When the desired product is the N-aminoimide, a quantity of hydrazine of be- 400000 00 09 tween the stoichiometric amount and a 50% molar excess, Ca and preferably a ratio anhydride/hydrazine substantially oe O*o* equal to 1, is used.

OB0,,S If a mole ratio anhydride/hydrazine of between 1 and 2 is used, a mixture of the above products is obtained, containing an amount of bis(imide) which increases o proportionately as the ratio is closer to 2 and as the temperature is raised.

irrespective of whether the products obtained in 15 accordane with the process according to the invention are 00 0 0 "0 pure bis(imides), bis(imide) N-aminoimide anhydride 00 0 00 mixtures, or N-aminoimide, these products are especially suitable as flame retardants in plastics of any kind.

Their incorporation in these plastics may be accomplished by any known method, at doses ranging from 5 to 40% rel- 4 ative to the weight of inflammable substance.

The examples which follow, in which the parts and percentages are expressed by weight, illustrate the invention without limiting the latter.

The products were identified by CHN and IR analysis.

The yield is expressed relative to the anhydride.

fXAMPLE 1 429 parts of commercial tetrachlorophthalic anhydride are dispersed in 2,000 parts of distilled water in a glass reactor equipped with a stirrer and a refluxing device. The pH of the suspension is Soo After this suspension has been brought to 60 0

C,

75 parts of 100% pure hydrazine hydrate are added gradually 0oo in the course of 20 to 30 minutes, and the reaction mix- .e ture is then brought to 100 0 C. 1,000 parts of distilled water are then added and the mixture is maintained at 100 0 C for a further 10 hours. A suspension is then obtained, which is cooled and filtered on a B'chner funnel.

After the residue is washed with water to neutral pH and dried under vacuum at 110-1200C, a white product is ob- 15 tained in a yield of more than 97%, the elemental and IR oa 0 S analysis of which product confirms the structure: 0 o0 l N- NH2

C

CHN elemental analysis S'Found Theory C 32.3 32.5 H 0.7 0.7 N 9.0 EXAMPLE 2 The procedure is as in Example 1, 445 parts of commercial chlorendir anhydride being dispersed in 4,000 8 parts of water.

The pH of the suspension is g of 100% pure hvdrazine hydrate are gradually added to the suspension, brought to 98 0

C.

After 10 hours' reaction at this temperature, the Smixture is cooled and the product separated by filtration.

9 00 4 After the residue is washed to neutral pH and 4 O4 Clo, dried under vaccum at 110 0 C-120 0 C, a grey product is obtained in a yield of more than 90%, the elemental and 9 I IR analysis of which product confirms the structure: dl 9c 1. M c. 9 0 4 C 0V c 0 l CL Cl S* N NH 2 Cl P/ 2 0 Cl 0 CHN elemental analysis i p r Measured Theoretical S" C 27.9 28.1 H 1.7 1.1 N 7.3 7.3 EXAMPLE 3 1,392 parts of tetrabromophthalic anhydride are dispersed in 4,000 parts of water in a six-Litre autocLave equipped with a stirre-. The pH of the dispersion is The mixture is brought to 600C and 225 parts of 100% pure hydrazine hydrate are then added gradually. The suspension is brought to 1250C under pressure and this -9temperature is maintained for 10 hours.

After this reaction time, the mixture is cooled and the product separated by filtration, After the residue is washed to neutral pH and dried under vacuum at 110-120 0 C, a yellow product is obtained in a yield of more than 90%, the elemental and

II

S IR analysis of which product indicates the structure: 0 0 0 o CHN analysis 10 Found Theoretical ot. @O 0 C 19.58 20.1 H 0.32 0.4 0 EXAMPLE 4 The procedure is as in ExampLe 3, but using a 100% molar excess of hydrazine hydrate. The same product is obtained as in Example 3, in a 97.4% yield.

EXAMPLE 883 p. of commercial tetrabromophthalic anhydride are dispersed in 2,600 p. of distilled water in a fourlitre autoclave equipped with a stirrer; this mixture is brought with stirring to a temperature of 170 0 C, which corresponds to a pressure of between 7.6 and 8 bars.

53 parts of 100% pure hydrazine hydrate, diluted 4i, 4 3;3;~:?uPmm~ 0 4 4 0 @40 00.4 00 PO o 4 @4 04 4 44 4) o 44 0 04 O 44 40 40 4 o

DO

00 0 6 60 0 0 10 with 200 parts .f distilled water (mole 'atio TBPA/HH are introduced gradually into the stirred suspension by means of a pump.

The reaction medium is maintained, still at 170 0

C,

for 6 hours, and is then cooled and filtered and the product washed. After being dried at 100-110 0 C under vacuum, a white product is obtained in a 95% yield, containing: 83% of N,N'-bis(tetrabromophthalimide) 14% of N-aminotetrabromophthalimide 3 of tetrabromophthalic anhydride EXAMPLE 6 The efficacy of the products according to the invention as flame-retardant agents for plastics was tested according to the following general procedure: Using a planetary or "barrel" type mixer, the resin in powder or granule form is mixed with the test ftame-retardant and the optional additives (antimony trioxide, paraffin) in the proportions indicated in the following tables. After homogenization, the mixture is extruded by means of a suitable extruder (twin-screw, single-screw or "Buss type") equipped or otherwise with a means of outgassing, working at the extrusion temperature stated by the supplier of the resin and linked with the melting point of the polymer. The compound obtained, optionally granulated, is then converted to test specimens for measurement by means of an injection moulding press working at the appropriate temperatures. These test Li F 1 S 11 specimens are then subjected to standardized tests of fire resistance UL94 at 3.2 mm and 1.6 mm (Standard NF T51072) and oxygen value OV (Standard NF T51071).

The Table A summarizes the results obtained in the case of polybutylene terephthalate (TMNO-ORGATER, granules marketed by the Applicant).

00 0 0 04rr 04 0 4 04 4 #4I 06 0 0 2

I-

TEST NO. I control II III IV Flame retardant of Example no. None 1 3 Composition (parts by weight) TMNO-ORGATER resin 1000 1000 100 1000 Flame retardant 0 142 160 186 Antimony trioxide 0 74 76 78 Paraffin 0 18 18 18 Results of the tests: UL94 NC VO VO VO OV 22 27.6 32.2 31.3 Colour of the test specimen: white ivory yellow ivory white white

Claims

1. Process for preparing halogenated imides by condensation of hydrazine and a halogenated dicarboxylic acid anhydride of the formula r X 0 S I C lD 1 IC 0 O P X /0 L 0 S° 1I o 04I 0n Swhere X represents an atom of bromine chlorine, and m is a whole number from 2 to 4, .n and p aLe whole numbers from 0 to 2, or a mixture o 0 of such anhydrides, wherein the reaction is performed in an aqueous medium, at temperature between 40 and 225°C, with an anhydride/hydrazine molar ratio less than 2. 0000 o9 0 4 a 2. rhe process according to Claim 1, in which the reaction is performed under pressure at a temperature of at least 140 0 C. o 0 000000 0 3. Process according to Claim 1 or 2, in which the reaction is performed starting with an aqueous dispersion or solution of anhydride having a pH of less than 7. 0

4. Process according to any one of Claims 1 to 3, in which tetrabromophthalic anhydride, tetrachlorophthalic anhydride, chlorendic anhydride or bromendic anhydride or a mixture of these anhydrides, is used. 1 40/Diak 150/C.C. -V t 13 Process according to any one of claims 1 to 4, In which hydrazine Is used in the form of c hydrate or hydrazinlum salt.

6. Process according to any one of claims 1 to 5, In which a mole ratio anhydride/hydrazine of greater than 1 but always less than 2, is used.

7. Process according to any one of claims I to 5, in which a mole rctio anhydride/hydrazine substantially equal to 1 is used. 4444*4

8. A method for the fireproofing of plastics comprising the use of the :,:•products obtained according to the process of any one of claim I to 7.

9. Plastics fireproofed by incorporating therein a product obtained according to the process of any one of claims 1 to 7. DATED this 3rd day of September, 1991. 4 6ATHEM WATERMARK PATENT TRADEMARK ATTORNEYS THE ATRIUM 290 BURWOOD ROAD HAWTHORN VICTORIA 3122 AUSTRAUA Z"/