PROCESS FOR PREPARING AN ORGANIC SULFONE

Abstract

A process for preparing polyaryl ethers in which a polycondensation of the monomer building blocks is carried out using microwave irradiation leads to thermoplastic molding compositions having improved color properties.

Claims

1. A process for the preparation of an organic sulfone by oxidation of the respective sulfoxide in the presence of at least one peroxide comprising at least one carboxylic acid which is liquid at 40 C. and has a miscibility gap with water at 40 C. and atmospheric pressure.

2. The process as claimed in claim 1 wherein the solubility of water in the at least one carboxylic acid is less than 2% by weight at 40 C., based on the water/carboxylic acid solution and atmospheric pressure.

3. The process as claimed in any one of the preceding claims wherein the at least one carboxylic acid is an aliphatic C.sub.6 to C.sub.10 carboxylic acid.

4. The process as claimed in any one of the preceding claims wherein the at least one carboxylic acid is 2-ethylhexanoic acid or isononanoic acid.

5. The process as claimed in any one of the preceding claims wherein the peroxide is hydrogen peroxide.

6. The process as claimed in any one of the preceding claims comprising removal of water during the oxidation.

7. The process as claimed in any one of the preceding claims comprising the presence of at least one further acid with a pK.sub.a of less than 3.

8. The process as claimed in any one of the preceding claims wherein the organic sulfone has a structure according to formula (I) ##STR00032## wherein R1 and R2 are independently from each other substituted or unsubstituted C.sub.6 or C.sub.10 aryl, wherein the substituents are halogen, hydroxy, cyano, nitro, linear or branched C.sub.1 to C.sub.5 alkyl, or linear or branched C.sub.1 to C.sub.5 alkoxy, linear or branched, substituted or unsubstituted C.sub.1 to C.sub.20 alkyl, wherein the substituents are halogen, tertiary hydroxy, cyano, nitro, carboxy, substituted or unsubstituted C.sub.6 to C.sub.10 aryl, C.sub.2 to C.sub.10 alkenyl, linear or branched C.sub.1 to C.sub.5 alkoxy, C.sub.5 to C.sub.7 cycloalkyl or C.sub.5 to C.sub.7 cycloalkenyl, linear or branched, substituted or unsubstituted C.sub.3 to C.sub.20 alkenyl, wherein the substituents are halogen, tertiary hydroxy, cyano, nitro, C.sub.1 to C.sub.5 alkoxy or linear or branched C.sub.1 to C.sub.10 alkyl.

9. The process as claimed in any one of the preceding claims wherein the organic sulfone has a melting point of at least 40 C.

10. The process as claimed in any one of the preceding claims wherein the sulfone is 4,4-dichlorodiphenylsulfone having a structure according to formula (II) ##STR00033##

11. The process as claimed in any one of claims 9 to 10 wherein organic sulfone which is precipitated during the oxidation is at least partially re-dissolved in the at least one carboxylic acid.

12. The process as claimed in any one of claims 10 to 11 comprising contacting the organic sulfone with at least one aqueous base.

13. The process as claimed in any one of claims 10 to 12 wherein the at least one carboxylic acid is recycled.

14. The process as claimed in claim 13 wherein the at least one carboxylic acid contains sulfoxide.

15. Use of the organic sulfone obtained from 4,4-dichlorodiphenyl sulfoxide according to the process as claimed in any of the preceding claims for the manufacture of a polymer comprising sulfoxide groups.

16. A fiber, film or shaped article produced using a polymer obtained according to claim 15

Description

EXAMPLES

List of Abbreviations

[0084] 2-EHA 2-ethyihexanoic acid
DCDPSO 4,4-dichlorodiphenylsulfoxide
DCDPS 4,4-dichlorodiphenylsulfone
AcOH glacial acetic acid

[0085] The solubility of 4,4-dichlorodiphenylsulfoxide/-sulfone in 2-ethyihexanoic acid at room temperature (22 C.) was determined by formation of a saturated solution of 4,4-dichlorodiphenylsulfoxide/-sulfone in 2-EHA. A GC spectra was recorded from the liquid phase and the 4,4-dichlorodiphenyl sulfoxide/-sulfone amount determined in area-%.

[0086] The nitrogen gas flow is given as relative gas flow in NI/h/kg according to DIN 1343, Jan. 1990.

Examples 1 and 2: Effect of Peroxide Concentration without Removal of Water

[0087] 50 g DCDPSO (0.18 mol) were suspended in 250 g of the at least one carboxylic acid (2-EHA) with 20 mol % of an additional acid (H.sub.2SO.sub.4 (98%, 0.04 mol)). The mixture was heated to 80 C. and an aqueous solution of H.sub.2O.sub.2 was added (see Table I) so that the temperature of the reaction mixture did not increase over 85 C. The addition was completed after 1 h. The mixture was stirred at 80 C. for the time t given below. The entire process was carried out under a nitrogen atmosphere (16 NI/h/kg). Afterwards, the reaction mixture was heated to 100 C. for 1 h to destroy unconverted H.sub.2O.sub.2. During this time, the entire solid dissolved and precipitated after cooling down to 40 C. The solid was filtered off and the mother liquor was separated. The filter cake was washed with cyclohexane. After drying the solid, DCDPS was obtained as white crystalline powder.

TABLE-US-00002 TABLE I Yield.sup.a) Purity H.sub.2O.sub.2 H.sub.2O.sub.2 t DCDPS DCDPS Example % equiv. h % % 1 50 1.5 21.3 97 98.9 2 70 1.2 4.3 98 99.7 .sup.a)isolated yield

Examples 3 to 5: Effect of Removal of Water

[0088] 50 g DCDPSO (0.18 mol) were suspended in 250 g of the at least one carboxylic acid with an additional acid (H.sub.2SO.sub.4 (98%, 0.04 mol) as given in Table II below. The mixture was heated to 80 C. and 1.2 equiv. of a 50% by weight aqueous solution of H.sub.2O.sub.2 was added so that the temperature of the reaction mixture did not increase above 85 C. The addition was completed after 1 h. The mixture was stirred at 80 C. for the time t given below. During the entire process, water was stripped off with a nitrogen flow of 70 to 160 NI/h/kg. Afterwards, the reaction mixture was heated to 100 C. for 1 h to destroy unconverted H.sub.2O.sub.2. During this time, the entire solid dissolved and precipitated after cooling down to 40 C. The solid was filtered off and the mother liquor was separated. The mother liquor of example 3 was reused for example 8. The filter cake was washed with cyclohexane. After drying the solid, DCDPS was obtained as white crystalline powder.

TABLE-US-00003 TABLE II Yield.sup.a) Purity H.sub.2SO.sub.4 t DCDPS DCDPS Example Carboxylic acid mol % h % % 3 2-EHA 20 3.0 94 99.5 4 Isononanoic acid 20 3.0 91 99.5 5 2-propylheptanoic acid 21 4.3 85 98.7 .sup.a)isolated yield

Examples 6 and 7: Effect of Removal of Water and Washing Solution

[0089] 100 g DCDPSO (0.37 mol) were suspended in 500 g of the at least one carboxylic acid (2-EHA) containing H.sub.2SO.sub.4 (98%, 0.04 mol). The mixture was heated to 80 C. A stream of nitrogen gas was blown continuously through the reaction mixture with a nitrogen flow given in Table III. Then 1.2 equiv. of a 50% by weight aqueous solution of H.sub.2O.sub.2 was added at such a rate that the temperature of the reaction mixture did not increase above 85 C. The addition was completed after 1 h. The mixture was stirred at 80 C. for the time t given below. Afterwards, the reaction mixture was heated to 100 C. for 1 h to destroy unconverted H.sub.2O.sub.2. During this time, the entire solid dissolved and precipitated after cooling down to 40 C. The solid was filtered off and the mother liquor was separated. The filter cake was washed with an aqueous solution of sodium hydroxide in water (2.5% by weight) and water. After drying the solid, DCDPS was obtained as white crystalline powder (see Table III).

TABLE-US-00004 TABLE III Relative Washing Yield.sup.a) Purity c[H2O] in c[2-EHA] gas flow Pressure t Solvent Water DCDPS DCDPS distillate in distillat Example Nl/h/kg mbar h ml ml % % % % 6 40 100 0.5 2 85 3 50 89 99.8 80 20 7 250 1000 0.5 2 100 5 100 91 99.9 92 8 .sup.a)isolated yield

[0090] The amount of 2-EHA in the distillate could be isolated by phase separation and reused without any further purification.

Examples 8 and 9: Effect of Recycling of the Solvent

[0091] The filtrate of 2-EHA, which contained remainder of unreacted DCDPSO, from example 3 was used as solvent for example 8. The amount of carboxylic acid was adjusted with fresh 2-EHA. The recycled carboxylic acid of example 8, which contained remainder of unreacted DCDPSO, was used in example 9. The amount of carboxylic acid was adjusted with fresh 2-EHA. Otherwise examples 8 and 9 were carried out as example 3. The isolated yields and the time t are given in Table 4.

TABLE-US-00005 TABLE IV Amount of fresh Yield.sup.a) Purity adjusted c[H2O] in c[2-EHA] t DCDPS DCDPS 2-EHA distillate in distillat Example h % % g % % 3 3.0 94 99.5 92 8 8 4.2 105 98.9 19.3 92 8 9 2.2 99 99.7 19.3 92 8 Overall 99 .sup.a)isolated yield

Comparative Examples C.SUB.1 .to C.SUB.4.: Effect of Nature of Carboxylic Acid and Recycling of the Solvent

Comparative Example C1

[0092] 100 g DCDPSO (0.37 mol) were suspended in 200 g of the at least one carboxylic acid (AcOH). The mixture was heated to 80 C. under an atmosphere of nitrogen (22 NI/h/kg). Then 1.2 equiv. of a 50% by weight aqueous solution of H.sub.2O.sub.2 was added at such a rate that the temperature of the reaction mixture did not increase above 85 C. The addition was completed after 1.5 h. The mixture was stirred at 80 C. for 0.7 h. Afterwards, the reaction mixture was heated to 100 C. The entire solid dissolved and precipitated after cooling down to room temperature. The solid was filtered off and the mother liquor was reused for comparative example C2. It was observed that the filter cake contained a substantial amount of AcOH. Therefore, the filter cake was washed with 2175 ml water and 1150 ml cyclohexane. After drying the solid, DCDPS was obtained as white crystalline powder (89%, purity 99.9%).

Comparative Example C2

[0093] 100 g DCDPSO (0.37 mol) were suspended in 183 g of the mother liquor, from comparative example C1 and additionally, 27 g of fresh AcOH was added. The mixture was heated to 80 C. under an atmosphere of nitrogen (22 NI/h/kg). Then 1.2 equiv of a 50% by weight aqueous solution of H.sub.2O.sub.2 was added so that the temperature of the reaction mixture did not increase over 85 C. The addition was completed after 1.5 h. The mixture was stirred at 80 C. for 2 h. Due to low conversion of DCDPSO of 79% but full conversion of H.sub.2O.sub.2, additional 0.3 equiv of a 50% by weight aqueous solution of H.sub.2O.sub.2 were added. The mixture was stirred at 80 C. for 2 h. Afterwards, the reaction mixture was heated to 100 C. The entire solid dissolved and precipitated after cooling down to room temperature. The solid was filtered off. The filter cake was washed with 2175 ml water and 1150 ml cyclohexane. After drying the solid, DCDPS was obtained as white crystalline powder (77%, purity 97.31%).

[0094] If glacial acetic acid was recycled in this way, the reaction time increased and the yields dropped.

Example C3

[0095] 100 g DCDPSO (0.37 mol) were suspended in 300 g of the at least one carboxylic acid (AcOH). The mixture was heated to 80 C. and 1.2 equiv of a 50% by weight aqueous solution of H.sub.2O.sub.2 was added at 800 mbar so that the temperature of the reaction mixture did not increase over 85 C. The addition was completed after 1.5 h. During the entire process, water was stripped off with a nitrogen flow of 58 NI/h/kg. The mixture was stirred at 80 C. for 1 h. Afterwards, the reaction mixture was heated to 100 C. The entire solid dissolved and precipitated after cooling down to room temperature. The solid was filtered off and the mother liquor was separated. It was observed that the filter cake contained a substantial amount of AcOH. The filter cake was washed with 2175 ml water and 1150 ml cyclohexane. After drying the solid, DCDPS was obtained as white crystalline powder (91%, purity 99.9%).

[0096] The concentration of AcOH in the distillate was determined to be 84% whereby the rest was water, 16%. A phase separation was not observed. The mother liquor was reused for comparative example C4.

Comparative Example C4

[0097] 100 g DCDPSO (0.37 mol) were suspended in 259 g of the mother liquor from comparative example C3. Additionally, 60 g of fresh AcOH were added. The mixture was heated to 80 C. and 1.2 equiv of a 50% by weight aqueous solution of H.sub.2O.sub.2 were added so that the temperature of the reaction mixture did not increase over 85 C. The addition was completed after 1 h. During the entire process, water was stripped off with a nitrogen flow of 55 NI/h/kg. The mixture was stirred at 80 C. for 1 h. Afterwards, the reaction mixture was heated to 100 C. The entire solid dissolved and precipitated after cooling down to room temperature. The solid was filtered off. It was observed that the filter cake contained a substantial amount of AcOH. The filter cake was washed with 2175 ml water and 1150 ml cyclohexane. After drying the solid, DCDPS was obtained as white crystalline powder (97%, purity 99.8%).

[0098] The concentration of AcOH in the destillate was determined to be 82% whereby the rest was water, 18%. A phase separation was not observed.

Example 10: Test of Solubility of Water in Carboxylic Acids

[0099] The solubility of water was determined in carboxylic acids at 40 C. The amount was noted:

TABLE-US-00006 Carbonic acid T ( C.) c[H2O] 2-EHA 40 1.77% by weight (17.7 g/1000 g) Isononanoic acid 40 1.80% by weight (18.0 g/1000 g)

[0100] At higher amounts, separation into two phases was observed.

[0101] Gas chromatography (GC):

[0102] Column: DB5 60 m0.32 mm0.25 m,

[0103] conditions: 100 C.-15K/, 200 C.-10-5K/250 C.-15K/ 300 C. 5

[0104] Inj. 300 C.

[0105] Det. 300 C.

[0106] Const. flow 2.4 ml N.sub.2/min