Method for producing monodisperse, amido-methylated vinyl-aromatic bead polymers

Abstract

The invention relates to a method of producing monodisperse amidomethylated vinylaromatic bead polymers, to ion exchangers prepared from these monodisperse amidomethylated vinylaromatic bead polymers by alkaline hydrolysis, to the method of using said monodisperse amidomethylated vinylaromatic bead polymers in the manufacture of ion exchangers and chelating resins, and also to the method of using these ion exchangers in the removal of heavy metals and noble metals from aqueous solutions or gases.

Claims

1. A one-pot method for producing monodisperse amidomethylated vinylaromatic bead poiymers, the method comprising contacting: at least one monodisperse vinylaromatic bead polymer; at least one compound of formula (I) or salts thereof ##STR00003## where R.sub.1=—CH(C.sub.1-C.sub.6-alkyl)- or —CH.sub.2—, and R.sub.2=—CH—(C.sub.1-C.sub.6-alkyl)- or —CH.sub.2—, or R.sub.1 and R.sub.2 combine to form a C.sub.6-C.sub.14-arylene, or R.sub.1 and R.sub.2 together represent —CH═CH—; and at least one condensed formaldehyde, wherein the at least one condensed formaldehyde comprises paraformaldehyde, or trioxane, or mixtures thereof, together in a one-pot process in the presence of at least one protic add and at least one organic solvent at a temperature of 55° C. to 75° C. to produce monodisperse amidomethylated vinylaromatic bead polymers.

2. The method as claimed in claim 1, wherein the temperature is 62° C. to 68° C.

3. The method as claimed in claim 1, wherein the at least one protic acid comprises sulfuric acid, hydrochloric acid, oleum, or mixtures thereof.

4. The method as claimed in claim 1, wherein the at least one organic solvent comprises chlorinated aliphatic hydrocarbons.

5. The method as claimed in claim 4, wherein the ratio of solvent to compound of formula (I) is 5.5:1 to 8.5:1.

6. The method as claimed in claim 1, wherein the at least one organic solvent comprises chlorinated C.sub.1-C.sub.6-alkanes.

7. The method of claim 1, wherein R.sub.1 and R.sub.2 together form phenylene, optionally substituted by C.sub.1-C.sub.4-alkyl.

8. The method of claim 1, wherein the compounds of formula (I) are phthalimide, succinimide or maleimide.

9. The method of claim 1, wherein the compounds of formula (I) are phthalimide.

10. The method as claimed in claim 1, wherein: the temperature is 62° C. to 68° C.; the compounds of formula (I) are phthalimide, succinimide or maleimide; the at least one protic acid is sulfuric acid, hydrochloric acid, oleum, or mixtures thereof; the at least one organic solvent is a chlorinated C.sub.1-C.sub.6-alkene; a ratio of the at least one organic solvent to the compounds of formula (I) is 5.5:1 to 8.5:1; and the at least one condensed formaldehyde is paraformaldehyde, trioxane, or mixtures thereof.

11. A monodisperse amidomethylated vinylaromatic bead polymer produced by the process of claim 1.

Description

EXAMPLE 1

(1) Preparation of Monodisperse Macroporous Bead Polymer on the Basis of Styrene, Divinylbenzene and Ethylstyrene

(2) A 10 l glass reactor is charged with 3000 g of completely ion-free water, and a solution of 10 g of gelatin, 16 g of disodium hydrogenphosphate dodecahydrate and 0.73 g of resorcinol in 320 g of completely ion-free water is added and mixed in. The mixture is equilibrated to 25° C. Subsequently, while stirring, a mixture of 3200 g of microencapsulated monomer droplets having a narrow particle size distribution, composed of 5% by weight of divinylbenzene and 1% by weight of ethylstyrene (used in the form of a commercial isomer mixture of divinylbenzene and ethylstyrene with 80% divinylbenzene), 0.4% by weight of dibenzoyl peroxide, 56.3% by weight of styrene and 37.5% by weight of isododecane (technical isomer mixture having a high proportion of pentamethylheptane) is applied, the microcapsule consisting of a formaldehyde-hardened complex coacervate composed of gelatin and a copolymer of acrylamide and acrylic acid, and 3200 g of aqueous phase having a pH of 12 are added. The mean particle size of the monomer droplets is 460 μm.

(3) The mixture s stirred and polymerized to completion by increasing the temperature in accordance with a temperature programme beginning at 25° C. and ending at 95° C. The mixture is cooled, washed through a 32 μm sieve and then dried at 80° C. under reduced pressure. This gives 1893 g of a polymer in bead form having a mean particle size of 440 μm, narrow particle size distribution and smooth surface.

(4) The polymer has a chalky white appearance and a bulk density of about 470 g/l.

(5) 1.1. Preparation of Monodisperse Macroporous Anion Exchanger Having Tertiary Amino Groups —CH.sub.2N(CH.sub.3).sub.2— Reaction at 45° C.

(6) A monodisperse macroporous anion exchanger having aminomethyl groups —CH.sub.2NH.sub.2— is prepared here as an intermediate stage. 1.2. Preparation of Phthalimidomethylated Monodisperse Macroporous Bead Polymer

(7) Apparatus: 4-liter four-neck flask, metering funnel, thermometer, heating bath, stirrer 1503 ml of 1,2-dichloroethane are initially charged at room temperature. 252.5 g of monodisperse macroporous bead polymer from Example 1 are metered into the initial charge. The suspension is stirred at room temperature for 2 hours. This is followed by the metered addition of 117.3 g of 91 wt % paraformaldehyde and 507.8 g of phthalimide. The suspension is heated to 45° C. At this temperature, the mixture is stirred for 0.5 hours. Within 2 hours, 677 g of sulfuric acid monohydrate are then metered in at 45° C. Subsequently, the suspension is then stirred at this temperature for 3 hours. The warm reaction broth is filtered off with suction. 2 liters of completely ion-free water are metered in. Residual amounts of 1,2-dichloroethane are removed by distillation. The mixture is then cooled and the volume of resin is determined.

(8) Volume yield: 1350 ml

(9) Dry weight: 0.454 g per ml of resin

(10) 1.3. Preparation of Aminomethyl-containing Monodisperse Macroporous Bead Polymer

(11) Apparatus: 4-liter autoclave, stirrer, thermometer

(12) At room temperature, 826 ml of completely ion-free water are initially charged. A mixture of 371 ml of completely ion-free water and 567 of 50 wt % aqueous sodium hydroxide is metered in. While stirring, 1330 ml of resin prepared according to example 1.1 are metered in.

(13) The suspension is heated to 180° C. and stirred at this temperature for a further 8 hours. Thereafter, the suspension is cooled. The resultant bead polymer is removed by means of a sieve and washed to neutrality with completely ion-free water.

(14) Volume yield: 950 ml

(15) Projected onto overall yield of intermediate stage: 964 ml

(16) Total base quantity formed—product of HCl number and overall yield of resin: 1822 mmol

(17) HCl number: 1.89 mol/l

(18) Delivery form: 30 ml

(19) Chloride form: 44 ml

(20) Second base form: 35 ml—these 35 ml weigh: 9.609 g

(21) First substitution: 0.81

(22) 1.4. Preparation of Dimethylamino-containing Monodisperse Macroporous Bead Polymer

(23) Apparatus: 4 liter four-neck flask, condenser, stirrer, thermometer, Dulcometer

(24) 1380 ml of completely ion-free water, 289.8 g of 36 wt % aqueous formalin solution and 920 ml of resin from Example 1.2. are initially charged at room temperature. The suspension is heated to 40° C. The pH is adjusted to pH 3 by metered addition of 85 wt % aqueous formic acid. A reaction program is then pursued as follows:

(25) Heat to 55° C. and stir at 55° C. for a further 0.5 hours

(26) Then heat to 70° C. and stir at 70° C. for a further 0.5 hours

(27) Heat to 80° C. and stir at 80° C. for a further 0.5 hours

(28) Then heat to reflux temperature—about 97° C. The pH 3 is maintained throughout the entire heating phase by metered addition of 85 wt % formic acid. On reaching reflux temperature, pH 2 is established in the course of 0.5 hours. First with the remaining formic acid, then with 96 wt % sulfuric acid. This is followed by stirring at pH 2 for 0.5 hours. pH 1 is then established. Further sulfuric acid is then metered in over 0.5 hours as required, followed by a further 10 hours of stirring under reflux. The suspension is then cooled down, and the resin is separated off via a sieve and washed with completely ion-free water.

(29) Altogether, 207 g of 85 wt % formic acid and 266.3 g of 96 wt % sulfuric acid are metered in.

(30) Volume yield: 1400 ml

(31) The entire amount of resin is filled into a column and downwardly treated with 3 bed volumes of 4 wt % aqueous sodium hydroxide solution. The excess of aqueous sodium hydroxide solution is then washed off with 5 bed volumes of completely ion-free water.

(32) Volume yield: 1050 ml

(33) Projected onto overall yield of resin: 1100 ml

(34) Total base quantity formed—product of HCl number and overall yield of resin: 1584 mmol

(35) HCl number. 1.44 mol/l

(36) Delivery form: 50 ml

(37) Chloride form: 66 ml

(38) Second base form: 50 ml

(39) Resin stability 99% entire beads

EXAMPLE 2

(40) Preparation of Monodisperse Macroporous Anion Exchanger Having Tertiary Amino Groups —CH.sub.2N(CH.sub.3).sub.2— reaction at 65° C.

(41) A monodisperse macroporous anion exchanger having aminomethyl groups —CH.sub.2NH.sub.2— is prepared here as an intermediate stage.

(42) 2.1. Preparation of Phthalimidomethylated Monodisperse Macroporous Bead Polymer

(43) Apparatus: 4-liter four-neck flask, metering funnel, thermometer, heating bath, stirrer

(44) 1503 ml of 1,2-dichloroethane are initially charged at room temperature. 252.5 g of monodisperse macroporous bead polymer from Example 1 are metered into the initial charge. The suspension is stirred at room temperature for 2 hours. This is followed by the metered addition of 117.3 g of 91 wt % paraformaldehyde and 507.8 g of phthalimide. The suspension is heated to 65° C. At this temperature, the mixture is stirred for 0.5 hours. Within 2 hours, 677 g of sulfuric acid monohydrate are then metered in at 65° C. Subsequently, the suspension is then stirred at this temperature for 3 hours. The warm reaction broth is filtered off with suction. 2 liters of completely ion-free water are metered in. Residual amounts of 1,2-dichloroethane are removed by distillation. The mixture is then cooled and the volume of resin is determined.

(45) Volume yield: 1475 ml

(46) Dry weight: 0.45 g per ml of resin

(47) 2.2. Preparation of Aminomethyl-Containing Monodisperse Macroporous Bead Polymer

(48) Apparatus: 4-liter autoclave, stirrer, thermometer

(49) At room temperature, 855 ml of completely ion-free water are initially charged. A mixture of 424 ml of completely ion-free water and 649 g of 50 wt % aqueous sodium hydroxide is metered in. While stirring, 1455 ml of resin prepared according to example 2.1 are metered in.

(50) The suspension is heated to 180° C. and stirred at this temperature for a further 8 hours. Thereafter, the suspension is cooled. The resultant bead polymer is removed by means of a sieve and washed to neutrality with completely ion-free water.

(51) Volume yield: 1050 ml

(52) Projected onto overall yield of intermediate stage: 1064 ml

(53) Total base quantity formed—product of HCl number and overall yield of resin: 2288 mmol

(54) HCl number: 2.15 mol/l

(55) Delivery form: 30 ml

(56) Chloride form: 43 ml

(57) Second base form: 34 ml—these 34 ml weigh: 9.016 g

(58) First substitution: 0.98

(59) 2.3. Preparation of Dimethylaminomethyl-containing Monodisperse Macroporous Bead Polymer

(60) Apparatus: 4 liter four-neck flask, condenser, stirrer, thermometer, Dulcometer

(61) 1530 ml of completely ion-free water, 365.5 g of 36 wt % aqueous formalin solution and 1020 ml of resin from Example 2.2. are initially charged at room temperature. The suspension is heated to 40° C. The pH is adjusted to pH 3 by metered addition of 85 wt % aqueous formic acid. A reaction program is then pursued as follows:

(62) Heat to 55° C. and stir at 55° C. for a further 0.5 hours

(63) Then heat to 70° C. and stir at 70° C. for a further 0.5 hours

(64) Heat to 80° C. and stir at 80° C. for a further 0.5 hours

(65) Then heat to reflux temperature—about 97° C. The pH 3 is maintained throughout the entire heating phase by metered addition of 85 wt % formic acid. On reaching reflux temperature, pH 2 is established in the course of 0.5 hours. First with the remaining formic acid, then with 96 wt % sulfuric acid. This is followed by stirring at pH 2 for 0.5 hours. pH 1 is then established. Further sulfuric acid is then metered in over 0.5 hours as required, followed by a further 10 hours of stirring under reflux. The suspension is then cooled down, and the resin is separated off via a sieve and washed with completely ion-free water.

(66) Altogether, 261.1 g of 85 wt % formic acid and 335.8 g of 96 wt % sulfuric acid are metered in.

(67) Volume yield: 1525 ml

(68) The entire amount of resin is filled into a column and downwardly treated with 3 bed volumes of 4 wt % aqueous sodium hydroxide solution. The excess of aqueous sodium hydroxide solution is then washed off with 5 bed volumes of completely ion-free water.

(69) Volume yield: 1180 ml

(70) Projected onto overall yield of resin: 1231 ml

(71) Total base quantity formed—product of HCl number and overall yield of resin: 2066 mmol

(72) HCl number: 1.678 mol/I

(73) Delivery form: 50 ml

(74) Chloride form: 65 ml

(75) Second base form: 50 ml

(76) Resin stability: 99% entire beads

(77) Table 3 presents a comparison of the characteristic data of the resins obtained in Examples 1 and 2.

(78) TABLE-US-00001 TABLE 3 Total base quantity Yield of Total base quantity HCI - number of Example/ Yield of Yield of at the level of the dimethylami- at the level of the dimethylami- reaction phthalimidometh- aminomethylated aminomethylated First nomethylated dimethylami- nomethylated bead temperature ylated bead bead bead substi- bead nomethylated bead polymer in mol/ in ° C. polymer in ml polymer in ml polymer in mmol tution polymer in ml polymer in mmol liter of resin 1/45° C. 1350 964 1822 0.81 1100 1584 1.44 2/65° C. 1475 1064 2288 0.98 1231 2066 1.678

(79) Test Methods:

(80) Number of Perfect Beads as Obtained

(81) 100 beads are inspected under a microscope. The number of beads which are cracked or splintered is counted. The number of perfect beads is 100 minus the number of damaged beads.

(82) Volume Difference Chloride/OH Form

(83) Completely ion-free water is used to wash 100 ml of anion exchanger bearing basic groups into a glass column. 1000 ml of 3 wt % hydrochloric acid are passed through the column in the course of 1 hour and 40 minutes. The resin is then washed chloride-free with completely ion-free water. The resin is washed into a tamp volumeter under completely ion-free water and agitated to constant volume—volume V 1 of resin in chloride form.

(84) The resin is transferred back into the column. 1000 ml of 2 wt % aqueous sodium hydroxide solution are passed through the column. The resin is then washed alkali-free with completely ion-free water until the eluate is at pH 8. The resin is washed into a tamp volumeter under completely ion-free water and is agitated to constant volume—volume V2 of resin in the free base form (OH form).
Computation: V1−V2=V3
V3:V1/100=swelling difference chloride/OH form in %

(85) Determination of Amount of Basic Aminomethyl Groups in Aminomethylated Crosslinked Polystyrene Bead Polymer—HCl Number

(86) 100 ml of the aminomethylated bead polymer are agitated down in the tamp volumeter and subsequently washed with completely ion-free water into a glass column. 1000 ml of 2 wt % aqueous sodium hydroxide solution are passed through the column in the course of 1 hour and 40 minutes. Completely ion-free water is then passed through until 100 ml of phenolphthalein admixed eluate have a consumption of 0.1 N (0.1 normal) hydrochloric acid of not more than 0.05 ml.

(87) 50 ml of this resin are admixed in a glass beaker with 50 ml of completely ion-free water and 100 ml of 1N hydrochloric acid. The suspension is stirred for 30 minutes and then filled into a glass column. The liquid is drained off. A further 100 ml of 1N hydrochloric acid are passed through the resin for 20 minutes. 200 ml of methanol are then passed through. All the eluates are collected and combined and titrated with 1N aqueous sodium hydroxide solution against methyl orange.

(88) The number of aminomethyl groups in 1 liter of aminomethylated resin computes according to the following formula: (200−V).Math.20=mol of aminomethyl groups per liter of resin.

(89) Determination of Degree of Aminomethyl Substitution on Aromatic Rings of Crosslinked Bead Polymer

(90) The number of aminomethyl groups in the total amount of aminomethylated resin is determined by the above procedure.

(91) The amount of employed bead polymer—A in grams—is divided by the molecular weight to compute the molar amount of aromatics which is present in this amount.

(92) For example, 300 g of bead polymer are converted into 950 ml of aminomethylated bead polymer having 1.8 mol/l of aminomethyl groups.

(93) 950 ml of aminomethylated bead polymer contain 2.82 mol of aromatics.

(94) So 1.8/2.81=0.64 mol of aminomethyl groups is present per aromatic.

(95) The degree of aminomethyl substitution on the aromatic rings of the crosslinked bead polymer is 0.64.