IL23994A - Manufacture of polysulphones - Google Patents

Description

PA TENTS AND DESIGNS ORDINANCE We, IMPERIAL CHEMICAL INDUSTRIES LIMITED, a British Company of Imperial Chemical House, Millbank, London, S. W. 1. , England DO HEREBY DECLARE the nature of this invention, and in what manner the same is to be performed to be particularly described and ascertained in and P.17732 The present invention relates to the manufacture of polyaryl sulphones from aromatic sulphonyl halides.

Polyaryl sulphones containing repeating units of the formula -Ar-SOg- may be manufactured by a process which comprises melting together a reagent of the formula H-Ar-SOg-X and/or an equimolar mixture of reagents of the formulae X.SOg-Ar-SOg.X and H-Ar-H in the presenoe of from 0.0¾? to ¾?. by weight of the reagents of antimony pentachloride or of a salt of iron which is soluble in the polymerisation mixture. In these formulae X is a halogen (preferably chlorine) atom and Ar is a bivalent aromatic radical, preferably derived from benzene, a polynuclear hydrocarbon containing not more than two aromatic rings, or a compound of the Formula I ( n which Y is a direot link or is -0-s -SO-, -S02~, -C0~, a divalent hydrocarbon radical, or a residue of a diol, each benzene ring bearing one of tha two valencies of the radioal Ar) or ring-substituted derivatives thereof, and Ar may vary from unit to unit in the chain of the polymer produced. - The polyaryl sulphones are generally strong thermoplastic materials of high softening point. Those containing units of the Formula. II ha e especially desirable properties; P.17732 in this formula B. , E. , R and R are preferably hydrogen atoms but may also be halogen atoms or alkyl or alkoxy groups having from 1 to i carbon atoms, and Z is -0- or -S- and may also be a direct link in some of the units .

The manufacture of polyaryl sulphones by this process in the presence of diluents has hitherto been avoided because the presence of a diluent tended to slow down the reaction and lead to products of low molecular weight s Thus polymerisation in the presence of nitromethane and 1 ,1 -dioxothiolan ( cyclic tetramethylene sulphone) yielded produots having reduced viscosities of only 0*01+† and 0<,07 respectively, even after six hours or more of reaction* Polymerisation in the absence of diluents , however, has many disadvantages. For example, as polymerisation continues the mixture loses mobility and eventually becomes solid despite progressive increase in temperature, and in order to obtain products of high molecular weight it may be neoessary to stop the reaction, grind the solid product into powder form and then continue the polymerisation in the solid phase . Such a two-stage process is cumbersome and uneconomic * Further, at the high temperatures required to obtain products of high molecular weight by this process there is danger of cross-linking when the reagents include a disulphonyl halide. A further disadvantage is the loss of volatile reagents during the reaction at theee high temperatures .

It has now been found, unexpectedly, that these polyaryl sulphonea can be successfully manufactured at a temperature^ riot v exoe ding 1 0°C in solution in a nitrobenzene of the. Formula IU; (in) P.17732 in this formula A is a hydrogen or halogen atom or an alkyl, cyano 2 or nitro group and A is a hydrogen or halogen atom or an alkyl group, the alkyl groups having not more than carbon atoms each. Nitrobenzene itself is preferred because it is readily available and is liquid at a suitable range of temperatures.

The reaction is effected at a temperature not greater than 60°C because the produot of reactions effected at higher temperatures ia generally discoloured to a significant extent. The preferred range of temperature is from 100- 2*£>°C, at which the products suffer little or no discolouration. Although temperatures below 10C°C (and even as low as 20°C) may be used, they result in prolonged reaction The nitrobenzene diluent or solvent is preferably used in amounts of not more than 5 parts per part by weight of the polymer-isable reagents* Using more diluent than this is not only uneconomic but generally leads to products of reduced molecular weight. On the other hand, with a very small amount of diluent the mixture tends to set to a solid mass during polymerisation, particularly when products of high molecular weight are being obtained. This causes difficulty in removing the material from the vessel and may even damage it. The preferred amounts of diluent are from 0,75 *° 3 parts per part by weight of the polymerisable reagents. Equal weights of diluent and monomer have been found to give very good results.

The use of a diluent according to the invention enables- the range of oatalysts to be extended beyond antimony pentachloride and the salts of iron soluble in the polymerisable mixture. As, well as antimony pentachloride and ferric chloride, and also ferric fluoride, ferrous bromide, ferrous iodide, ferric orthophosphate and ferrous and ferric acetoacetonates, other Lewis acids may be used whioh are capable of generating a sulphonylium cationic species -(Ar-SOp) P.17732 from an aromatic sulphonyl halide -(Ar-SOg.X) dissolved in a nitrobenzene of Formula III. Such Lewis acids may be found, for example, among the higher halidea (especially fluorides and chlorides) of the elements of variable valency occurring in Groups IV to VIII of the periodic table. Antimony pentachloride and ferric chloride are particularly effective, but molybdenum pentachloride and tungsten hexaohloride are also good and titanium tetrafluoride, zirconium tetrachloride and antimony pentafluoride are> among the other effective catalysts. The optimum amount of catalyst is generally equal to or somewha!t above the minimum that will enable full conversion of the polymerisable monomers into the polyaryl sulphones; amounts larger than this offer no further advantage in speed of reaction or increase of molecular weight and may be troublesome to remove from the product. The optimum amount depends on the particular catalyst employed; ferric chloride, for example, is preferably used at not less than about 0.25 mole/iOO moles of the polymerisable reagents, and antimony pentachloride is preferably used at not less than about 0»5 mole/100 moles.

The us:e of;a- small molar excess of the disulphonyl halide X.S02-Ar-S02.X lea-ds-to the more consistent production .. of products of high molecular -weight, both where a '.mixture' . ·, of X.S02-Ar-S02<,X and H-Ar-H is used and where H-Ar-SOg.X is used.

Moisture tends to have an adverse effect on the polymerisation and is preferably kept very low.

The physical properties of the products depend upon their molecular weight and the choice of starting material but with suitable choice of reagents and conditions polyaryl sulphones of high molecular weight, excellent thermal stability and high softening point may be obtained. The amorphous polymers are soluble in a number of organic solvents and are generally strong, frequently transparent, and are stable for long periods in molten form. They are therefore eminently P.17732 suitable for fabrication by shaping processes for plastios such as injection moulding, compression moulding and extrusion,, They may also be cast or spun from solution to yield films and fibres,, By polymerising in the presence of a diluent, the products may be obtained in solution ready for de-ashing if desired, for example by treatment with a chelating agent for the catalyst. A further advantage of using a diluent is that the reaction between a di sulphonyl halide of the formula X . SOg-Ar-SOgoX compound of the formula H-Ar-Ή occurs without the tendency shown in the absence of a. diluent and at the higher temperatures to yield cross-linked products. The use of the disulphonyl halide is commercially advantageous because its preparation is simpler and cheaper than that of the momosulphonyl hali.de of the formula H-Ar-SO g cX.

The following examples illustrate the invention. All viscosity measurements are reduced viscosities measured on solutions of polymer (1 g) in dimethyl formamide (100 cm^) at 25°C EXAMPLE 1 Diphenyl ether 4-sulphonyl chloride (16»8 g) was dissolved in nitrobenzene ( 27 .8 g) . This solution ( 6 cm^) was placed in a flask heated at 1 20°C and provided with a stirrer, a condenser and an inlet for passing dry nitrogen over the mixture. The solution was then stirred thoroughly at 1120° C for 10 minutes under an atmosphere of nitrogen and then ferric chloride (62.5 m j Ο.385 millimole) was added as 1 cm'^ of a 6.25 w/v solution in nitrobenzene. After a further 4 hours, the flask was cooled and the solution diluted by the addition of dimethyl formamide ( 20 cm ) » The polymer was then precipitated by adding the solution to methanol. The solid was then filtered off, washed with methanol and dried at 150°C for 48 hours at an absolute pressure of 0.1 torr. The product was f ound to have a reduced viscosity of 0. .

P.17732 - EXAMPLE Three further polymerisation reactions were carried out and the polymers isolated as described in Example 1 , except that additional nitrobenzene was added initially and the solutions were held at 120°C for a longer time after the ferric chloride was added,, The amounts of additional nitrobenzene, the polymerisation times, and the reduoed viscosities of the products: are listed below in comparison with the product of Example 1.

Additional Polymerisation Reduced nitrobenzene time viscosity 0 cm" 3 h 0 min 0.42 4 cm" 5 h 10 min 0.34 8 cm"5 6 h 30 min 0.24 12 om"5 25 h 0 min 0*19 Thus, the use of increasing amounts of diluent tends to reduce the molecular weight of the polymerio product and this reduotion is not offset by increasing the reaction time.

EXAMPLE 3 Five further polymerisation reactions were carried out as described in Example 1 but at different temperatures: Q0°Cf 100°C, 1'30°C, 1:50°C and 180°C. The product of each was made up to a volume' of 30 cm^ with fresh dry nitrobenzene, cooled to room temperature, and washed four times with hydrochloric acid solution. After a final wash with water, they were poured into methanol to precipitate the polymer which was filtered, washed and dried in the manner described in Example 1i . A film was compression-moulded from a sample of each at 290°C using a pressure of 31.5 kg/mm and a three-minute cycle.

A visual comparison of the films showed a darkening in colour in the sample prepared at 150°C and a marked deterioration in colour in the sample prepared at 180°C.

EXAMPLE Four polymerisation flasks were set up each containing diphenyl ether (1.702 g; 1;0*0 ndllimole), diphenyl ether , -disulphonyl chloride (3.672 g; 10»0 millimole) and nitrobenzene (10 cm ) ; the solutions were heated to 20°C and stirred under nitrogen. To each was, added ferric chloride (as- a solution in nitrobenzene) in the amounts shown in the table below. After 22 hours the polymerisation products were; isolated by adding the solutions to methanol, filtering off the products and washing them with fresh methanol s and then drying them at 150°C for 24 hours under 0.2 torr to give the polymers whose yields and reduoed viscosities; are shown in the following table* ■ Fcerri ·c ■ ui -J Polymer Reduced — — — — — chloride added yi .eld, vi .scosi .t ,y 8* mg (0.05 millimole) 4.7 g 0.18 16.2 mg (0,10 millimole) 4»8 g 0. 7 3 .4 mg (0,20 millimole) 4-7 g 0»07 68c4 mg (0.42 millimole) 4.6 g 0.22 EXAMPLE 5 A solution of diphenyl ether (6.808 g; 40e0 millimole) and diphenyl ether 4>V -disulphonyl chloride (14.688 gj 40.0 millimole) in nitrobenzene (20 cm ) was heated to 130°C and maintained at this temperature for 5 minutes; then ferric chloride (64.8 mg; 0»400 millimole) was added as a 3»81 cm^ of a 1 «-7$ w/v solution in nitrobenzene to induce polymerisation. During the whole reaotion nitrogen from a cylinder of the liquid was passed continuously over the mixture.

Analysis showed that it contained 1300 parts of water per million by volume. On completion of the polymerisation, the product was isolated by adding the solution to methanol, filtering off the solid, washing it with fresh methanol and drying it at 150°C under an absolute pressure of 0e2 torr for 24 hours to yield a polymer having a reduced P.17 2 In a repeat of this process, the nitrogen supply to the reaction vessel was first passed up a 6 cm tower packed with phosphorus pentoxide on vermiculite. All connections were made with copper tubing to minimise moisture permeation through the tube walls into the nitrogen supply. Analysis of the treated nitrogen showed that it contained only 9 parts of water per million by volume. In this case, the polymeric product was found to have a reduced viscosity EXAMPLE 6 Diphenyl ether (3.0 g; 20.0 millimole) was dissolved in nitrobenzene (10 cm^) with excess diphenyl ether 4,4' -cLi sulphonyl chloride (7·413 g; 20.2 millimole) at 130°C under an atmosphere of dry nitrogen (i.e. nitrogen containing less than about 50 parts of water per million by volume). The solution was stirred for 5 minutes and then ferric ohloride (32.4 mgj 0.200 millimole) was added as 1.91 cm' of a « w/v to initiate polymerisation. After 3.5 hours, the solution was diluted with nitrobenzene (10 cm ) and stirred. Half the resultant solution was then removed and cooled, the remainder being maintained at 130°C for a total of 22 hours. After isolation and drying, the two samples of polymer obtained were found to have reduced viscosities of 0.70 and 1.9 respectively. Both were wholly soluble both in cold nitrobenzene and in cold dimethyl formamide.

By way of comparison, when diphenyl ether was similarly heated with diphenyl ether 4A' -disulphonyl chloride in the absence of diluent, using ferric chloride ( mg) as catalyst and a final temperature of about 235-240°C, the separated polymeric product after washing and drying was found to be about 4<$ insoluble in nitrobenzene and dimethyl formamide. The soluble fraction had a reduced viscosity of 0.31.

P.17732 3-, 1 ,2-diphenaxyethane (4, 286 gj 20„0 millimole) and diphenyl ether i s * -disulphonyl chloride (7< 342 gs 20<>0 millimole) were dissolved in nitrobenzene (10 cm ) and the solution was heated to 1i30°C under dry nitroge β After 5 minutes s ferric chloride (32«4 mgj 0o200 millimole) was added as 1 <>80 cm^ of a 1 .8 w/v solution in nitro enzene,, After 1 0 minutes at this temperature nitrobenzene (90 cm^) was added and the solution was cooled to room temperature* It was washed four times by stirring rigorously with j *j0 hydrochloric acid and then twice with distilled water, and was then added to stirred methanol to precipitate the product* Further washing with methanol and drying at 150°C for 2 hours gave a polymer (9-8 g) with a reduced viscosity of 0»71 » Analysis showed it to contain 0©003 iron and 0*07$ ash. The polymer was readily compression-moulded at 250°C to give almost transparent films. It was amorphous on X-ray examination.

EXAMPLE 8 Dibenzofuran (3 »364 g| 20„0 millimole) and diphenyl ether 4,4* -disulphonyl chloride (7»432 g; 20„0 millimole) were dissolved in nitrobenzene (10 cm ) and heated at 20°C under dry nitrogen.

The solution was stirred at this temperature for 4 minutes; ferric chloride (28 mgj 0„ 7 millimole) was then added as 0.7 cm of a 4*Q¾ w/v solution in nitrobenzene, and the reaction was continued for 22 hours at 20°C . Nitrobenzene (ΙΌΟ crn^) was added and the product was isolated as described in Example "to give an amorphous polymer (8.7 g) having a reduced viscosity of 0»48. Colourless films could be compression moulded at 310°C using a pressure of 3ΐ ·5 kg mm » EXAMPLE 9 ,2-diphenoxyethane (2'»21'0 g; 1 0„3 millimole) and diphenyl 484' -disulphonyl chloride (3 °522 g; 10„5 millimole) were dissolved P.17732 in nitrobenzene (10 cm ) and heated at 1 20°C under dry nitrogen* Ferric chloride ( 8 mg; 0.05 millimole) was added as 0,2 cm^ of a *0 w/v solution in nitrobenzene. After 17 hours at 120°C, the product was precipitated by adding dimethyl formamide ( 0 cm ) and pouring into stirred methanol. On washing and drying an amorphous polymer (5 »1 g) was obtained having a reduced viscosity of 0.21 .

EXAMPLE 0 Diphenyl 4,4' -disulphonyl chloride (3.522 g; 10.5 millimole) and dibenzofuran (1 .682 g; 10.0 millimole) were dissolved in nitro-benzene (10 cm^) and heated at 1 20°C under dry nitrogen. Ferric chloride (8 mgj 0.05 millimole) was added as 0o2 cm^ of a 4«0$ w/v solution in nitrobenzene . Three minutes after addition of the catalyst polymer began to precipitate from solution. After 1 6 hours at 120°C the mixture was diluted with dimethyl formamide and filtered. The precipitate was washed well with methanol and dried. The polymer (3 »1 g) was found to be crystalline on X-ray examination and insoluble in all common solvents .

EXAMPLE 11 Diphenyl ether (17-02 g; 100 millimole) and diphenyl ether 4,4' -disulphonyl chloride (37.065 g; 101 millimole) were dissolved in nitrobenzene (50 cm^) at 130°C under an atmosphere of dry nitrogen and ferrio chloride ( 97 m 0.60 millimole) was added as a solution in 5 g of nitrobenzene. After 3 ·5 hours, a sample was removed from the reaction vessel and diluted with further nitrobenzene and the product was precipitated by pouring into methanol. After drying, the polymer was found to have a reduced viscosity of 0.70. The remainder of the reaction mixture was allowed to polymerise for a total of 6.75 hours, to yield a final produot which, after separation, washing and drying, had a reduced viscosity of 1 . 8.

P.17732 EXAMPLE 1 2 Diphenyl ether (34«04 gj 200 millimole) and diphenyl ether , ' -di.3ulphonyl chloride (74· 13 gj 202 millimole) were diasolved in nitrobenzene (1Ό0 cm^) at 130°C under an atmosphere of dry nitrogen. After 6 minutes, ferric chloride (304 mg; 1 .87 millimole) was added as a solution in 1 8 g of nitrobenzene, and the mixture was allowed to polymerise for 5 ·5 hours. The viscous produot was cooled, diluted with nitrobenzene (800 cm^) and then stirred vigorously with 5N hydrochloric acid solution (100 cm^) . After separation of the aqueous layer, the washing with hydrochloric acid was repeated four times and the final wash was followed by a wash with sodium carbonate solution and four washes with water. The polymer was then precipitated by pouring the nitrobenzene solution into methanol. It was filtered off, extracted with methanol for 24 hours, and dried at 1 70°C for 48 hours under an absolute pressure of 0.2 torr to give a polymer ( 87 g) having a reduced viscosity of 0.70. A film 0. 27 mm thick was compression-moulded from a sample of the polymer at 300°C and a pressure of 31 ·5 kg/mm and was: found to have a yield point under tensile stress of 10.05 kg/mm at 20°C .

EXAMPLE 3 Diphenyl ether (17.02 gj 100 millimole) and diphenyl 4,4' -di sulphonyl chloride (35.40 gj 106 millimole) were dissolved in nitrobenzene (50 cm ) and heated with stirring at 140°C under dry nitrogen. Ferric chloride (137 m j 0.84 millimole) was injected as 8.10 cm^ of a 1 .6S w/v solution in nitrobenzene using a hypodermic syringe. The polymerisation was terminated after 6 hours by adding molten diphenyl ether (1 cm^) , and the mixture was stirred for a further 7 hours at 140°C . It was then poured into methanol in a maceratorj and the solid was filtered off, suspended in fresh methanol, and heated under reflux for 24 hours . The product was P.17732 filtered off and dried at 100°C in vaouum for 17 hours to give a polymer (44·9 g) having a reduced viscosity of 0«55» The polymer was compression-moulded into blocks 5o08 x 2.54 x 1.27 cm"5 and into film 0.18 mm thick at 280°C, 300°C, 320°C, 340°C and 60°C« The materials became progressively deeper in colour as. the temperature was inoreased. The films obtained at 280°C and 300°C showed evidence of internal strain, and that moulded at 360°C showed some evidence of decomposition.

EXAMPLE 1 Diphenyl ether -sulphonyl chloride (1Ο7.48 gj 400 milli-mole) was dissolved in nitrobenzene ( 00 cm ) and the solution was allowed to equilibrate at 120°C. Antimony pentachloride (0„39 cm j «05 millimole) wae added as 0 cm^ of a 1.3 v/v solution in nitrobenzene and the mixture was stirred for hours at 120°C. Aniline (5 om^) in nitrobenzene (ΙΌΟ cts?) was added to terminate the reaction and the mixture was stirred at 120°C for another hour. The solution was added to methanol in a macerator, and the precipitated product was washed twice with hot methanol and then with acetone, and dried at T90°C for 24 hours at 0.1 torr to yield a polymer (89 g) having a reduced viscosity of 0*72. It was compression-moulded at 240°C into specimens 7.62 x 5·08 x 0. cm'5.

NOTE The table below shows the amounts of nitrobenzene in parts by weight per part by weight of polymerisable reagent (monomer) that were used in the polymerisation mixtures of the foregoing examples, after taking account of the additional nitrobenzene introduced with the catalyst. It also shows the amount of catalyst employed in moles per 100 moles of the polymerisable reagents, the catalyst being antimony pentachloride in Example l£tand ferric chloride in the other examples. _ - Parts of nitrobenzene Moles of catalyst per Example er part of monomer 100 moles of monomer 1 2.1 2.9 2 3. , 4·3» 5· 2.9 3 2.1 2.9 4 2.2 0.25, 0.50, 1 1.33 0.50 6 1.32 0.50 7 1.22 0.50 8 1.19 0.43 9 2.13 0.24 2.35 0.24 1 1.20 0.30 12 1.28 0.47 1!3 1.33 0.41 1!4 1.45 0.76

Claims (1)

1. P.17732 ^ Having now particularly described and ascertained the nature of Our said invention and in what^ nner the aarne is to be performed, we dec !l ■are that what we claim is : ■ · ' ,■ · ■ ■ . . 1 , A process for the manufacture of polyaryl sulphones containing repeating units of the formula -Ar-SOg- from a reagent of the formula H-Ar-SOj.X and/or a mixture of reagents of the formulae X.S0„-Ar-S0 .X /and H-Ar-H, in which formulae X; is a , halogen atom and' Ar is a bivalent 5 aromatic radical, characterised in that the polymerisation is carried outat a temperature not exceeding 1'60°C in solution in a ' riitrobersene of the formula in which A is a hydrogen or halogen atom or an alkyl, cyano or nitro 2 1Ό group and A is a hydrogen or halogen atom or an alkyl group , the alkyl groups having not more than 4 carbon a toms each, using as catalyst a Lewis acid capable of generating a sulphonylium cationic species -(Ar-SOg) * from an aromatic sulphonyl halide -(Ar-SO^.X) dissolved in a nitrobenzene of the above formula. 15 o A process according to Claim 1 , characterised in that 0<>75 to 3 parts by weight of the nitrobenzene are used per part by weight of the polymerisable reagents. 5 , A process according to Claim 1 or Claim 2, characterised in that the solvent is nitrobenzene . 20 .+.» A procese according to any of Claims 1 to 3 , characterised in that the polymerisation is carried out at 100~140°C » 5, A process according to any of Claims 1 to , characterised in that the catalyst is antimony pentachloride or a salt of iron soluble in the polymerisation mixture and is employed at 0 »0¾¾ to 25 2 - by weight of the polymerisable reagents . 6. A process aocording to Claim * characterised in that the catalyst is antimony pentachloride employed at not less than 0»5 mole per 00 moles of the polymerisable reagents. P.17732 7 · A process according to Claim 5 » characterised in that the catalyst is ferric chloride employed at not less than 0e25 mole per 100 moles of the polymerisable reagents i 8» A process according to any of Claims to 7» wherein the bivalent aromatic radical Ar .in the polymerisable reagents is derived from benzene, a polynuolear hydrocarbon containing not more than two aromatic rings, or a oompound of the formula . (in whioh Y is a direct link, or is -0-, -S-, -SO-, -SOg-.,. -CO-, a divalent hydrocarbon radical, or a residue of a diol) each benzene ring, bearing one . of the two valencies of the radical Ar) or ring-: substituted derivatives; thereof and Ar may vary from unit to unit in the chain of the polymer' produced* o A process according to .Claim, .8, wherein the polymerisable reagents o on tain units of the formula in whioh R , R , atoms or alkyl or alkoxy groups having from to k carbon atoms, and Z is -0-_, or -S- and may also be a direct link in some of the units. 10 A process according to Claim , substantially as herein desoribed with reference to the examples* 11 . A polyaryl sulphone when manufactured by a process as claimed in any of Claims 1 to, 1 0 or its obvious chemioal equivalent* DATED the 18th day of JULY,