Method for preparing keto-functionalized aromatic (meth)acrylates

Abstract

The invention relates to a method for preparing keto-functionalized aromatic (meth)acrylates.

Claims

1. A method for the preparation of a keto-functionalized aromatic (meth)acrylate, comprising reacting a keto-functionalized aromatic alcohol or a keto-functionalized aromatic amine with (meth)acrylic anhydride in the presence of a catalyst, wherein the catalyst is an acid with a pK.sub.a of <2 or a base with a pK.sub.b of <9, in which reactants, products formed and catalyst are present together in a reaction matrix at a reaction temperature of between 50° C. and 120° C., and wherein: a) the reactants, products formed and catalyst have a residence time in the reaction matrix that is restricted to from 0.1 to, at most, 4 hours; and b) the (meth)acrylic anhydride used comprises a content of (meth)acrylic acetic anhydride of <4.5%.

2. The method of claim 1, wherein the keto-functionalized aromatic alcohol or the keto-functionalized aromatic amine has its keto function adjacent to the aromatic system.

3. The method of claim 1, wherein the keto-functionalized aromatic alcohol or the keto-functionalized aromatic amine comprises either a free NH.sub.2 or a free OH group on its aromatic system.

4. The method of claim 1, wherein the keto-functionalized aromatic (meth)acrylate is precipitated by addition of water or of an organic solvent into the reaction mixture and is isolated in solid form by filtration.

5. The method of claim 1, wherein the keto-functionalized aromatic alcohol or the keto-functionalized aromatic amine comprises either a free NH.sub.2 or a free OH group linked via a spacer unit to its aromatic system.

6. The method of claim 5, wherein the spacer unit is, or comprises, an oligoether, alkyl, aryl, ether, thioether, amine, ester, thioester, or amide.

7. The method of claim 1, wherein the reaction matrix further comprises a stabilizer at the start of the reaction and the stabilizer is present at a concentration of between greater than 0 and 5000 ppm based on the keto-functionalized aromatic alcohols or amines used.

8. The method of claim 1, wherein the (meth)acrylic anhydride used has a purity of >93% and the reaction has a duration of 1 to 3 hours.

9. The method of claim 1, wherein: a) said catalyst is an acid and, after the reaction is complete, the catalyst is neutralized with a base; and b) after neutralization, the Pt—Co colour index is, or is adjusted to <500 APHA, measured as a 30 wt % solution of the keto-functionalized aromatic (meth)acrylate in 60 wt % methyl methacrylate and 10 wt % methacrylic acid.

10. The method of claim 1, wherein the product is treated with an adsorbent and, after the treatment, the adsorbent is removed to give a product with a Pt—Co colour index of <500 APHA measured as a 30 wt % solution of the keto-functionalized aromatic (meth)acrylate in 60 wt % methyl methacrylate and 10 wt % methacrylic acid.

11. The method of claim 1, wherein the reaction is interrupted at a conversion of >90% of the keto-functionalized aromatic alcohol or keto-functionalized aromatic amine.

12. The method of claim 1, wherein the reaction is carried out in the presence of catalytic amounts of acid.

13. The method of claim 12, wherein said acid is sulfuric acid, alkylsulfonic acid or arylsulfonic acid.

14. The method of claim 12, wherein, after the reaction, the catalytic amounts of acid are neutralized with an aqueous base.

15. The method of claim 14, wherein the aqueous base is an aqueous alkali metal hydroxide solution or ammonia solution.

16. The method of claim 1, wherein the reaction is carried out over 1-3 hours at 60 to 95° C.

17. The method of claim 1, further comprising addition of a liquid (meth)acrylic ester or styrene into the reaction mixture at the end of the reaction.

18. The method of claim 3, wherein the keto-functionalized aromatic (meth)acrylate is precipitated by addition of water or of an organic solvent into the reaction mixture and is isolated in solid form by filtration.

19. The method of claim 18, wherein: a) said catalyst is an acid and, after the reaction is complete, the catalyst is neutralized with a base; and b) after neutralization, the Pt—Co colour index is, or is adjusted to <500 APHA, measured as a 30 wt % solution of the keto-functionalized aromatic (meth)acrylate in 60 wt % methyl methacrylate and 10 wt % methacrylic acid.

20. The method of claim 1, wherein (meth)acrylic anhydride is reacted with 4-hydroxybenzophenone and at the end of the reaction, and prior to processing, there is 0.723% or less of 4-(acetoxy)benzophenone in the product.

21. The method of claim 1, wherein the reaction is carried out in the presence of catalytic amounts of aqueous sodium hydroxide solution.

22. The method of claim 1, wherein the keto-functionalized aromatic alcohol is 4-hydroxybenzophenone or 4-chloro-4′-hydroxybenzophenone; and the keto-functionalized aromatic amine is 2-amino-5-chlorobenzophenone.

Description

EXAMPLES

Abbreviations Used

(1) 4-HBP 4-hydroxybenzophenone

(2) BpMA 4-(methacryloyloxy)benzophenone

(3) GC Gas chromatography

(4) MAAH methacrylic anhydride

(5) MAA methacrylic acid

(6) MMA methyl methacrylate

Example 1

(7) ##STR00015##

(8) Apparatus: 2 l four-necked round-bottom flask with mechanical stirrer, reflux condenser, Pt100 temperature sensor, air inlet tube and electrically heated oil bath.

(9) Mixture: 1.51 mol of 4-hydroxybenzophenone, 99.8%: 300 g 1.70 mol of MAAH (purity 98.48% (GC), methacrylic acetic anhydride 1.131%, acetic anhydride not detected; stabilized with 1871 ppm of 2,4-dimethyl-6-tert-butylphenol): 262.8 g 1.80 mol of MMA: 180 g 0.0087 mol of concentrated sulfuric acid: 0.846 g Total stabilizer content at start of reaction: 1639 ppm based on 4-hydroxybenzophenone.

(10) Neutralization of the catalyst acid with 1.57 g of (50% strength) aqueous sodium hydroxide solution Esterification of the excess methacrylic anhydride with 9.7 g of methanol (0.3 mol)

(11) For the preparation of the 30% strength solution in MMA: 600 g MMA

(12) Theoretical yield: 1354 g

(13) Procedure:

(14) The mixture was weighed out in full and then heated to 90° C. with stirring and introduction of air. The reaction time at 90° C. is 3 h. Cooling was then carried out, down to approximately 60° C., and the sodium hydroxide dissolved in water for neutralization of the catalyst sulfuric acid, and also the methanol for esterification of the unreacted methacrylic anhydride, were added. Here, the colour of the reaction mixture changed from red to yellow. Stirring was subsequently carried out for 1 h at 60° C., and then 600 g of methyl methacrylate were added to the mixture with stirring. The resulting solution was cooled to room temperature with stirring, and filtered. The solution of the 4-(methacryloyloxy)benzophenone in methyl methacrylate has the following composition, determined by gas chromatography (figures in wt %): 57.8% methyl methacrylate 10.0% methacrylic acid 0.30% 4-hydroxybenzophenone 0.62% 4-(acetoxy)benzophenone 29.4% 4-(methacryloyloxy)benzophenone

(15) The water content is 0.09%, the stabilizer content is 22 ppm of 2,4-dimethyl-6-tert-butylphenol. The Pt—Co colour index is 194 APHA.

(16) During the reaction, samples were taken and worked up separately (cooling to 60° C., neutralization with aqueous sodium hydroxide solution, reaction with MeOH, dilution with MMA). The conversion was determined by comparison of the 4-HBP signal with the starting value by means of GC.

(17) TABLE-US-00001 Content of the Colour index stabilizer used Conversion [APHA] after work-up 4-HBP after work-up [ppm] Reaching 89.6% 146 173 90° C. 15 min 95.2% 30 min 96.6% 45 min 97.1% 60 min 97.6% 140 130 75 min 97.4% 90 min 97.4% 120 min  97.5% 157 82 180 min  98.0% 198 23

(18) Yield: 1285 g (95% of theory)

Example 2

(19) ##STR00016##

(20) Apparatus: 2 l four-necked round-bottom flask with mechanical stirrer, reflux condenser, Pt100 temperature sensor, air inlet tube and electrically heated oil bath.

(21) Mixture: 1.51 mol of 4-hydroxybenzophenone, 99.7%: 300 g 1.70 mol of MAAH (purity 98.59% (GC), methacrylic acetic anhydride 0.40%, acetic anhydride not detected; stabilized with 2070 ppm of 2,4-dimethyl-6-tert-butylphenol): 262.8 g 1.80 mol of MMA: 180 g 0.0087 mol of concentrated sulfuric acid: 0.846 g Total stabilizer content at start of reaction: 1813 ppm based on 4-hydroxybenzophenone.

(22) Neutralization of the catalyst acid with 1.8 g of aqueous sodium hydroxide solution dissolved in 10 g of water

(23) Esterification of the excess methacrylic anhydride with 22.4 g of methanol

(24) Theoretical yield: 1354 g

(25) Procedure:

(26) The mixture was weighed out in full and then heated to 90° C. with stirring and introduction of air. The reaction time at 90° C. is 2 h. Cooling was then carried out, down to approximately 60° C., and the sodium hydroxide dissolved in water for neutralization of the catalyst sulfuric acid, and also the methanol for esterification of the unreacted methacrylic anhydride, were added. Stirring was subsequently carried out for 1 h at 60° C., and then 600 g of methyl methacrylate were added to the mixture with stirring. The resulting solution was cooled to room temperature with stirring, and filtered. The solution of 4-(methacryloyloxy)benzophenone in methyl methacrylate has the following composition, determined by gas chromatography (figures in wt %): 57.9% methyl methacrylate 10.0% methacrylic acid 0.28% 4-hydroxybenzophenone 0.32% 4-(acetoxy)benzophenone 29.8% 4-(methacryloyloxy)benzophenone

(27) The water content is 0.08%, the stabilizer content is 53 ppm of 2,4-dimethyl-6-tert-butylphenol. The Pt—Co colour index is 152 APHA.

(28) Direct comparison with example 1 shows that the starting concentration of methacrylic acetic anhydride in the methacrylic anhydride is critical for the amount of 4-(acetoxy)benzophenone found in the product.

(29) Yield: 1350 g (99.7% of theory)

Example 3

(30) ##STR00017##

(31) Apparatus: 2 l four-necked round-bottom flask with mechanical stirrer, reflux condenser, Pt100 temperature sensor, air inlet tube and electrically heated oil bath.

(32) Mixture: 1.51 mol of 4-hydroxybenzophenone, 99.7%: 300 g 1.70 mol of MAAH (purity 98.59% (GC), methacrylic acetic anhydride 0.40%, acetic anhydride not detected; stabilized with 2070 ppm of 2,4-dimethyl-6-tert-butylphenol): 262.8 g 1.80 mol of MMA: 180 g 0.0087 mol of concentrated sulfuric acid: 0.846 g Total stabilizer content at start of reaction: 1813 ppm based on 4-hydroxybenzophenone.

(33) Neutralization of the catalyst acid with 1.8 g of aqueous sodium hydroxide solution dissolved in 10 g of water

(34) Esterification of the excess methacrylic anhydride with 22.4 g of methanol

(35) Theoretical yield: 402.1 g

(36) Procedure:

(37) The mixture was weighed out in full and then heated to 90° C. with stirring and introduction of air. The reaction time at 90° C. is 2 h. Cooling was then carried out, down to approximately 60° C., and the sodium hydroxide dissolved in water for neutralization of the catalyst sulfuric acid, and also the methanol for esterification of the unreacted methacrylic anhydride, were added. Stirring was subsequently carried out for 1 h at 60° C., then the mixture was poured with stirring (metal paddle stirrer, stirring motor) as a thin stream into 1.5 l of water. After 0.5 h of stirring, the precipitate was isolated by suction filtration on a glass filter frit, washed twice again with in each case 1 l of water and subsequently dried using air on the suction filter. The solid was subsequently dried in air.

(38) Yield: 397.2 g (98.8% of theory)

(39) Analyses: Water content: 0.10% 2,4-dimethyl-6-tert-butylphenol: 120 ppm

(40) Gas Chromatography: 0.059% methyl methacrylate 0.011% methacrylic acid 0.659% 4-hydroxybenzophenone 0.723% 4-(acetoxy)benzophenone 98.23% 4-(methacryloyloxy)benzophenone

(41) Pt—Co colour index as 20% strength solution in acetone: 135.

(42) Direct comparison with example 2 shows that the contents of 4-hydroxybenzophenone and 4-(acetoxy)benzophenone are not significantly reduced by the precipitation. This highlights the importance of a (meth)acrylic anhydride with as low a content of (meth)acrylic acetic anhydride as possible for a pure product.

Example 4

(43) Apparatus: 2 l round-bottom flask with mechanical stirrer and reflux condenser.

(44) Mixture: 1 kg of the following solution: 30% of 4-(methacryloyloxy)benzophenone dissolved in 60% methyl methacrylate and 10% methacrylic acid directly from the process analogous to example 1, but with a higher colour index. 100 g of activated carbon rods (from Donau Carbon, Norit 0.8 Supra type)

(45) Procedure:

(46) The mixture was weighed out in full and stirred at room temperature. In the meantime, samples were taken continuously and were filtered by a pleated filter and a syringe filter (PTFE, pore size 0.45 μm).

(47) TABLE-US-00002 Time Pt—Co colour index Beforehand 335 ½ h stirring 208 1 h stirring 200 2 h stirring 210 4 h stirring 190 6 h stirring 210

(48) Here, the stabilizer content and the contents of 4-(methacryloyloxy)benzophenone, methyl methacrylate and methacrylic acid remained constant within the scope of measurement accuracy.

Example 5

(49) Apparatus: 2 l round-bottom flask with mechanical stirrer, reflux condenser, Pt100 temperature sensor, air inlet tube and electrically heated oil bath.

(50) Mixture: 1 kg of the following solution: 30% of 4-(methacryloyloxy)benzophenone dissolved in 60% methyl methacrylate and 10% methacrylic acid directly from the process analogous to example 1, but with a higher colour index. 100 g of activated carbon rods (from Donau Carbon, Norit 0.8 Supra type)

(51) Procedure:

(52) The mixture was weighed out in full and stirred at 40° C. In the meantime, samples were taken continuously and were filtered by a pleated filter and a syringe filter (PTFE, pore size 0.45 μm).

(53) TABLE-US-00003 Time Pt—Co colour index Beforehand 335 ½ h stirring 210 1 h stirring 191 2 h stirring 200 4 h stirring 205 6 h stirring 225

(54) Here, the stabilizer content and the contents of 4-(methacryloyloxy)benzophenone, methyl methacrylate and methacrylic acid remained constant within the scope of measurement accuracy.

Example 6

(55) Apparatus: 2 l round-bottom flask with mechanical stirrer and reflux condenser.

(56) Mixture: 800 g of the following solution: 30% of 4-(methacryloyloxy)benzophenone dissolved in 60% methyl methacrylate and 10% methacrylic acid directly from the process analogous to example 1, but with a higher colour index. 80 g of activated carbon rods (from Donau Carbon, Norit 0.8 Supra type)

(57) Procedure:

(58) The mixture was weighed out in full, stirred at room temperature for 1 hour and filtered by a pleated filter.

(59) TABLE-US-00004 Time Pt—Co colour index Beforehand 350 1 h stirring 235

(60) The filtered-off activated carbon had 300 ml of methyl methacrylate added to it, was stirred for 10 minutes at room temperature, and subsequently filtered off with suction. 5 g of the dried activated carbon had 50 g of the 4-(methacryloyloxy)benzophenone solution in methyl methacrylate and methacrylic acid added thereto, was stirred for ½ hour at room temperature and filtered by a pleated filter.

(61) TABLE-US-00005 Time Pt—Co colour index Beforehand 350 ½ h stirring 290

Example 7

(62) Apparatus: 250 ml glass beaker, magnetic stirrer.

(63) Mixture: 50 g of the following solution: 30% of 4-(methacryloyloxy)benzophenone dissolved in 60% methyl methacrylate and 10% methacrylic acid directly from the process analogous to example 1, but with a higher colour index. 5 g of Tonsil

(64) Procedure:

(65) The mixture was weighed out in full, stirred at room temperature for ½ hour and filtered by a pleated filter.

(66) TABLE-US-00006 Time Pt—Co colour index Beforehand 250 ½ h stirring 200

Example 8

(67) Apparatus: see example 1, but with 4 l flask.

(68) Mixture: 4.0 mol of 4-hydroxybenzophenone: 796.0 g 4.4 mol of methacrylic anhydride, (purity 98.65% (GC), methacrylic acetic anhydride 0.62%, acetic anhydride not detected; stabilized with 1980 ppm of 2,4-dimethyl-6-tert-butylphenol: 694.8 g 0.023 mol of H.sub.2SO.sub.4, conc., 0.15% of mixture: 2.26 g (1.23 ml) 2,4-dimethyl-6-tert-butylphenol, 1000 ppm of prod.=1065 mg

(69) Neutralization H.sub.2SO.sub.4: 0.052 mol NaOH=2.08 g dissolved in 10 g H.sub.2O Hydrolysis of methacrylic anhydride excess: 25.6 g MeOH (0.80 mol)

(70) Theoretical yield: 1051.7 g

(71) Procedure: The mixture was weighed out in full and then heated to 90° C. with introduction of air. Reaction time: 4 h (conversion check by GC). Cooling was then carried out down to approximately 60° C. and the NaOH dissolved in H.sub.2O for neutralization of the H.sub.2SO.sub.4, and also the MeOH for hydrolysis of the methacrylic anhydride, were added. Stirring was subsequently carried out for 1 h at 60° C., and then the mixture was completely cooled. The mixture was then poured with stirring (metal paddle stirrer, stirring motor) as a thin stream into 3 l of water. After ½ h of stirring, the precipitate was isolated by suction filtration on a glass filter frit, washed again with 2.0 l of H.sub.2O (stirred for approximately 30 minutes in a glass beaker with a stirring motor with metal paddle stirrer) and subsequently dried with suction on the suction filter. The solid was subsequently dried to constant mass in air (7 days).

(72) Yield: 1051.7 g=98.7% of theory

(73) Analyses: H.sub.2O: 0.06% 2,4-dimethyl-6-tert-butylphenol: 79 ppm GC: (data after reaction in area % based on the sum of the 4-hydroxybenzophenone derivatives)

(74) TABLE-US-00007 After reaction After precipitation 0.007% methacrylic acid 0.560% 1.066% 4-hydroxybenzophenone 0.700% 1.046% 4-acetoxybenzophenone 98.740% 97.142% 4-(methacryloyloxy)benzophenone

Example 9

(75) ##STR00018##

(76) Apparatus: 2 l four-necked round-bottom flask with mechanical stirrer, reflux condenser, Pt100 temperature sensor, air inlet tube and electrically heated oil bath.

(77) Mixture: 0.20 mol of 4-chloro-4′-hydroxybenzophenone: 47.48 g 0.22 mol of MAAH, (purity 97.92% (GC), methacrylic acetic anhydride 1.59%, acetic anhydride not detected; stabilized with 2035 ppm of 2,4-dimethyl-6-tert-butylphenol: 35.07 g 0.0013 mol of concentrated sulfuric acid: 0.124 g Total stabilizer content at start of reaction: 1503 ppm based on 4-chloro-4′-hydroxybenzophenone.

(78) Theoretical yield: 60.15 g

(79) Procedure:

(80) The mixture was weighed out in full and then heated to 90° C. with stirring and introduction of air. The reaction time at 90° C. is 4 h. Then the mixture was poured with stirring (metal paddle stirrer, stirring motor) as a thin stream into 0.18 l of water. After 0.5 h of stirring, the precipitate was isolated by suction filtration on a glass filter frit, washed twice again with in each case 0.18 l of water and subsequently dried using air on the suction filter. The solid was subsequently dried in air.

(81) Yield: 56.6 g (94% of theory)

(82) Gas chromatography: 1.344% of 4-chloro-4′-hydroxybenzophenone 1.307% 4-chloro-4′-acetoxpenzophenone 96.17% 4-chloro-4′-(methacryloyloxy)benzophenone

Example 10

(83) ##STR00019##

(84) Apparatus: 2 l four-necked round-bottom flask with mechanical stirrer, reflux condenser, Pt100 temperature sensor, air inlet tube and electrically heated oil bath.

(85) Mixture: 1.51 mol of 4-hydroxybenzophenone, 99.8%: 300 g 1.70 mol of MAAH (purity 98.48% (GC), methacrylic acetic anhydride 1.131%, acetic anhydride not detected; stabilized with 1871 ppm of 2,4-dimethyl-6-tert-butylphenol): 262.8 g 1.80 mol of MMA: 180 g 0.0227 mol of NaOH (50% in H.sub.2O): 1.816 g Total stabilizer content at start of reaction: 1639 ppm based on 4-hydroxybenzophenone.

(86) Esterification of the excess methacrylic anhydride with 9.7 g of methanol (0.3 mol) For the preparation of the 30% strength solution in MMA: 600 g of MMA

(87) Theoretical yield: 1354 g

(88) Procedure:

(89) The mixture was weighed out in full and then heated to 90° C. with stirring and introduction of air. The reaction time at 90° C. is 3 h. Cooling was then carried out, down to approximately 60° C., and the sodium hydroxide dissolved in water for neutralization of the catalyst sulfuric acid, and also the methanol for esterification of the unreacted methacrylic anhydride, were added. Stirring was subsequently carried out for 1 h at 60° C., and then 600 g of methyl methacrylate were added to the mixture with stirring. The resulting solution was cooled to room temperature with stirring, and filtered. The solution of 4-(methacryloyloxy)benzophenone in methyl methacrylate has the following composition, determined by gas chromatography (figures in wt %): 59.1% methyl methacrylate 10.5% methacrylic acid 0.32% 4-hydroxybenzophenone 0.46% 4-(acetoxy)benzophenone 29.1% 4-(methacryloyloxy)benzophenone

(90) The water content is 0.10%, the stabilizer content is 203 ppm of 2,4-dimethyl-6-tert-butylphenol.

(91) The Pt—Co colour index is 111 APHA.

(92) Yield: 1347 g (99% of theory)

Example 11

(93) ##STR00020##

(94) Apparatus: 2 l four-necked round-bottom flask with mechanical stirrer, reflux condenser, Pt100 temperature sensor, air inlet tube, electrically heated oil bath, pressure filter.

(95) Mixture: 1.51 mol of 4-hydroxybenzophenone, 99.8%: 300 g 1.70 mol of MAAH (purity 98.48% (GC), methacrylic acetic anhydride 1.131%, acetic anhydride not detected; stabilized with 1871 ppm of 2,4-dimethyl-6-tert-butylphenol): 262.8 g 0.30 mol of MMA: 30 g 0.0087 mol of concentrated sulfuric acid: 0.846 g Total stabilizer content at start of reaction: 1639 ppm based on 4-hydroxybenzophenone.

(96) Neutralization of the catalyst acid with 1.57 g of (50% strength) aqueous sodium hydroxide solution Esterification of the excess methacrylic anhydride with 9.7 g of methanol (0.3 mol)

(97) Theoretical yield: 402.1 g

(98) Procedure:

(99) The mixture was weighed out in full and then heated to 90° C. with stirring and introduction of air. The reaction time at 90° C. is 2 h. Cooling was then carried out, down to approximately 60° C., and the sodium hydroxide dissolved in water for neutralization of the catalyst sulfuric acid, and also the methanol for esterification of the unreacted methacrylic anhydride, were added. Stirring was subsequently carried out for 1 h at 60° C., and then 400 g of methylcyclohexane were added to the mixture with stirring. The resulting solution was cooled to room temperature with stirring and the solid which then precipitated out was filtered over a pressure filter. The filter residue was dried in air.

(100) Yield: 278.25 g (69.2% of theory)

(101) Gas Chromatography: 0.032 area % of methyl methacrylate 0.008 area % of methacrylic acid 0.329 area % of 4-hydroxybenzophenone 0.289 area % of 4-(acetoxy)benzophenone 98.71 area % of 4-(methacryloyloxy)benzophenone

Example 12

(102) ##STR00021##

(103) Apparatus: 2 l four-necked round-bottom flask with mechanical stirrer, reflux condenser, Pt100 temperature sensor, air inlet tube and electrically heated oil bath.

(104) Mixture: 1.51 mol of 4-hydroxybenzophenone, 99.7%: 300 g 1.70 mol of MAAH (purity 98.59% (GC), methacrylic acetic anhydride 0.40%, acetic anhydride not detected; stabilized with 2070 ppm of 2,4-dimethyl-6-tert-butylphenol): 262.8 g 1.80 mol of MMA: 180 g 0.0087 mol of sulfuric acid (50% in H.sub.2O): 1.692 g Total stabilizer content at start of reaction: 1813 ppm based on 4-hydroxybenzophenone.

(105) Neutralization of the catalyst acid with 1.8 g of aqueous sodium hydroxide solution dissolved in 10 g of water

(106) Esterification of the excess methacrylic anhydride with 22.4 g of methanol

(107) Theoretical yield: 1354 g

(108) Procedure:

(109) The mixture was weighed out in full and then heated to 90° C. with stirring and introduction of air. The reaction time at 90° C. is 3.5 h. Cooling was then carried out, down to approximately 60° C., and the sodium hydroxide dissolved in water for neutralization of the catalyst sulfuric acid, and also the methanol for esterification of the unreacted methacrylic anhydride, were added. Stirring was subsequently carried out for 1 h at 60° C., and then 600 g of methyl methacrylate were added to the mixture with stirring. The resulting solution was cooled to room temperature with stirring, and filtered. The solution of 4-(methacryloyloxy)benzophenone in methyl methacrylate has the following composition, determined by gas chromatography (figures in wt %): 57.8% methyl methacrylate 10.1% methacrylic acid 0.45% 4-hydroxybenzophenone 0.35% 4-(acetoxy)benzophenone 29.6% 4-(methacryloyloxy)benzophenone

(110) The water content is 0.10%, the stabilizer content is 61 ppm of 2,4-dimethyl-6-tert-butylphenol. The Pt—Co colour index is 142 APHA.

(111) Yield: 1346 g (99.4% of theory)

Example 13

(112) ##STR00022##

(113) Apparatus: 2 l four-necked round-bottom flask with mechanical stirrer, reflux condenser, Pt100 temperature sensor, air inlet tube and electrically heated oil bath.

(114) Mixture: 1.51 mol of 4-hydroxybenzophenone, 99.7%: 300 g 1.70 mol of MAAH (purity 98.59% (GC), methacrylic acetic anhydride 0.40%, acetic anhydride not detected; stabilized with 2070 ppm of 2,4-dimethyl-6-tert-butylphenol): 262.8 g 1.80 mol of MMA: 180 g 0.0087 mol of trifluoromethanesulfonic acid: 1.306 g Total stabilizer content at start of reaction: 1813 ppm based on 4-hydroxybenzophenone.

(115) Neutralization of the catalyst acid with 1.8 g of aqueous sodium hydroxide solution dissolved in 10 g of water

(116) Esterification of the excess methacrylic anhydride with 22.4 g of methanol.

(117) Theoretical yield: 1354 g

(118) Procedure:

(119) The mixture was weighed out in full and then heated to 90° C. with stirring and introduction of air. The reaction time at 90° C. is 3 h. Cooling was then carried out, down to approximately 60° C., and the sodium hydroxide dissolved in water for neutralization of the catalyst sulfuric acid, and also the methanol for esterification of the unreacted methacrylic anhydride, were added. Stirring was subsequently carried out for 1 h at 60° C., and then 600 g of methyl methacrylate were added to the mixture with stirring. The resulting solution was cooled to room temperature with stirring, and filtered. The solution of 4-(methacryloyloxy)benzophenone in methyl methacrylate has the following composition, determined by gas chromatography (figures in wt %): 57.7% methyl methacrylate 10.2% methacrylic acid 0.41% 4-hydroxybenzophenone 0.43% 4-(acetoxy)benzophenone 29.7% 4-(methacryloyloxy)benzophenone

(120) The water content is 0.07%, the stabilizer content is 48 ppm of 2,4-dimethyl-6-tert-butylphenol. The Pt—Co colour index is 158 APHA.

(121) Yield: 1348 g (99.4% of theory)

Example 14

(122) ##STR00023##

(123) Apparatus: 100 ml three-necked round-bottom flask with magnetic stirrer, reflux condenser, Pt100 temperature sensor, air inlet tube and electrically heated oil bath.

(124) Mixture: 0.05 mol of 2-amino-5-chlorobenzophenone: 11.6 g 0.053 mol of MAAH, (purity 98.51% (GC), methacrylic acetic anhydride 0.20%, acetic anhydride not detected; stabilized with 2160 ppm of 2,4-dimethyl-6-tert-butylphenol: 8.2 g 0.4 mmol of concentrated sulfuric acid: 0.039 g Total stabilizer content at start of reaction: 1527 ppm based on 2-amino-5-chlorobenzophenone.

(125) Theoretical yield: 15.0 g

(126) Procedure:

(127) The mixture was weighed out in full and then heated to 70° C. with stirring and introduction of air. The reaction time at 70° C. is 4 h. Then the mixture was poured with stirring (metal paddle stirrer, stirring motor) as a thin stream into 0.18 l of water. After 0.5 h of stirring, the precipitate was isolated by suction filtration on a glass filter frit, washed twice again with in each case 0.18 l of water and subsequently dried using air on the suction filter. The solid was subsequently dried in air.

(128) Yield: 14.0 g (93% of theory)

(129) Gas Chromatography: 0.11% of 2-amino-5-chlorobenzophenone 0.32% 2-acetamido-5-chlorobenzophenone 97,835% N-(2-benzoyl-4-chlorophenyl)methacrylamide

Comparative Example 1

(130) ##STR00024##

(131) Apparatus: 2 l four-necked round-bottom flask with mechanical stirrer, reflux condenser, Pt100 temperature sensor, air inlet tube and electrically heated oil bath.

(132) Mixture: 1.51 mol of 4-hydroxybenzophenone, 99.7%: 300 g 1.70 mol of MAAH (purity 98.59% (GC), methacrylic acetic anhydride 0.40%, acetic anhydride not detected; stabilized with 2070 ppm of 2,4-dimethyl-6-tert-butylphenol): 262.8 g 1.80 mol of MMA: 180 g 0.0087 mol of concentrated sulfuric acid: 0.846 g Total stabilizer content at start of reaction: 1813 ppm based on 4-hydroxybenzophenone.

(133) Neutralization of the catalyst acid with 1.57 g of (50% strength) aqueous sodium hydroxide solution Esterification of the excess methacrylic anhydride with 9.7 g of methanol (0.3 mol)

(134) For the preparation of the 30% strength solution in MMA: 600 g of MMA

(135) Theoretical yield: 1354 g

(136) Procedure:

(137) The mixture was weighed out in full and then heated to 90° C. with stirring and introduction of air.

(138) The reaction time at 90° C. is 5 h. The mixture polymerized on subsequent cooling to 60° C.

(139) Yield: —

Comparative Example 2

(140) ##STR00025##

(141) Apparatus: 2 l four-necked round-bottom flask with mechanical stirrer, reflux condenser, Pt100 temperature sensor, air inlet tube and electrically heated oil bath.

(142) Mixture: 1.51 mol of 4-hydroxybenzophenone, 99.7%: 300 g 1.70 mol of MAAH (purity 98.72% (GC), methacrylic acetic anhydride 0.827%, acetic anhydride not detected; stabilized with 1059 ppm of 2,4-dimethyl-6-tert-butylphenol): 262.8 g 1.80 mol of MMA: 180 g 0.0087 mol of concentrated sulfuric acid: 0.846 g 273 mg of 2,4-dimethyl-6-tert-butylphenol Total stabilizer content at start of reaction: 1835 ppm based on 4-hydroxybenzophenone.

(143) Neutralization of the catalyst acid with 1.57 g of (50% strength) aqueous sodium hydroxide solution Esterification of the excess methacrylic anhydride with 9.7 g of methanol (0.3 mol) For the preparation of the 30% strength solution in MMA: 600 g of MMA

(144) Theoretical yield: 1354 g

(145) Procedure:

(146) The mixture was weighed out in full and then heated to 90° C. with stirring and introduction of air. The reaction time at 90° C. is 5.5 h. After 5 h of reaction time, a sample was taken and worked up separately (cooling to 60° C., neutralization with aqueous sodium hydroxide solution, reaction with MeOH, dilution with MMA). After 5.5 h, the mixture polymerized.

(147) Yield: —

(148) Analyses: After work-up, the sample after 5 h reaction time showed a colour index of 600 APHA and also a stabilizer content of 9 ppm of 2,4-dimethyl-6-tert-butylphenol.

Comparative Example 3

(149) ##STR00026##

(150) Apparatus: 2 l four-necked round-bottom flask with mechanical stirrer, reflux condenser, Pt100 temperature sensor, air inlet tube and electrically heated oil bath.

(151) Mixture: 1.51 mol of 4-hydroxybenzophenone, 99.8%: 300 g 1.70 mol of MAAH (purity 82.63% (GC), methacrylic acetic anhydride 1.668%, acetic anhydride not detected; stabilized with 2870 ppm of 2,4-dimethyl-6-tert-butylphenol): 262.8 g 1.80 mol of MMA: 180 g 0.0087 mol of concentrated sulfuric acid: 0.846 g Total stabilizer content at start of reaction: 2514 ppm based on 4-hydroxybenzophenone.

(152) Neutralization of the catalyst acid with 1.57 g of (50% strength) aqueous sodium hydroxide solution Esterification of the excess methacrylic anhydride with 9.7 g of methanol (0.3 mol) For the preparation of the 30% strength solution in MMA: 600 g of MMA

(153) Theoretical yield: 1354 g

(154) Procedure:

(155) The mixture was weighed out in full and then heated to 90° C. with stirring and introduction of air.

(156) The reaction time at 90° C. is 6 h. Cooling was then carried out, down to approximately 60° C., and the sodium hydroxide dissolved in water for neutralization of the catalyst sulfuric acid, and also the methanol for esterification of the unreacted methacrylic anhydride, were added. Stirring was subsequently carried out for 1 h at 60° C., and then 600 g of methyl methacrylate were added to the mixture with stirring. The resulting solution was cooled to room temperature with stirring, and filtered. The solution of 4-(methacryloyloxy)benzophenone in methyl methacrylate has the following composition, determined by gas chromatography (figures in wt %): 60.3% methyl methacrylate 9.1% methacrylic acid 2.35% 4-hydroxybenzophenone 1.06% 4-(acetoxy)benzophenone 25.5% 4-(methacryloyloxy)benzophenone

(157) The water content is 0.11%, the stabilizer content is 330 ppm of 2,4-dimethyl-6-tert-butylphenol. The Pt—Co colour index is 147 APHA. Thus, the content of the unreacted keto-functionalized aromatic phenol relative to the content of keto-functionalized aromatic methacrylate is high enough that in application significant amounts can migrate or negatively influence the properties of the polymer.

(158) Yield: 1346 g (99% of theory)

Comparative Example 4

(159) ##STR00027##

(160) Apparatus: 2 l four-necked round-bottom flask with mechanical stirrer, reflux condenser, Pt100 temperature sensor, air inlet tube and electrically heated oil bath.

(161) Mixture: 1.51 mol of 4-hydroxybenzophenone, 99.8%: 300 g 1.70 mol of MAAH (purity 86.86% (GC), methacrylic acetic anhydride 4.96%, acetic anhydride not detected; stabilized with 1270 ppm of 2,4-dimethyl-6-tert-butylphenol): 262.8 g 1.80 mol of MMA: 180 g 0.0087 mol of concentrated sulfuric acid: 0.846 g 117 mg of 2,4-dimethyl-6-tert-butylphenol Total stabilizer content at start of reaction: 1502 ppm based on 4-hydroxybenzophenone.

(162) Neutralization of the catalyst acid with 1.57 g of (50% strength) aqueous sodium hydroxide solution Esterification of the excess methacrylic anhydride with 9.7 g of methanol (0.3 mol) For the preparation of the 30% strength solution in MMA: 600 g of MMA

(163) Theoretical yield: 1354 g

(164) Procedure:

(165) The mixture was weighed out in full and then heated to 90° C. with stirring and introduction of air. The reaction time at 90° C. is 6 h. Cooling was then carried out, down to approximately 60° C., and the sodium hydroxide dissolved in water for neutralization of the catalyst sulfuric acid, and also the methanol for esterification of the unreacted methacrylic anhydride, were added. Stirring was subsequently carried out for 1 h at 60° C., and then 600 g of methyl methacrylate were added to the mixture with stirring. The resulting solution was cooled to room temperature with stirring, and filtered. The solution of 4-(methacryloyloxy)benzophenone in methyl methacrylate has the following composition, determined by gas chromatography (figures in wt %): 59.4% methyl methacrylate 11.4% methacrylic acid 0.79% 4-hydroxybenzophenone 2.83% 4-(acetoxy)benzophenone 26.0% 4-(methacryloyloxy)benzophenone

(166) The water content is 0.08%, the stabilizer content is 140 ppm of 2,4-dimethyl-6-tert-butylphenol. The Pt—Co colour index is 165 APHA. Thus, the content of the acetylated keto-functionalized aromatic phenol relative to the content of keto-functionalized aromatic methacrylate is high enough that in application significant amounts can migrate or negatively influence the properties of the polymer.

(167) Yield: 1351 g (99% of theory)

Comparative Example 5

(168) ##STR00028##

(169) Apparatus: 2 l four-necked round-bottom flask with mechanical stirrer, reflux condenser, Pt100 temperature sensor, air inlet tube and electrically heated oil bath.

(170) Mixture: 1.51 mol of 4-hydroxybenzophenone, 99.8%: 300 g 1.70 mol of MAAH (purity 86.86% (GC), methacrylic acetic anhydride 4.96%, acetic anhydride not detected; stabilized with 1270 ppm of 2,4-dimethyl-6-tert-butylphenol): 262.8 g 1.80 mol of MMA: 180 g 0.0087 mol of concentrated sulfuric acid: 0.846 g 117 mg of 2,4-dimethyl-6-tert-butylphenol Total stabilizer content at start of reaction: 1502 ppm based on 4-hydroxybenzophenone.

(171) Neutralization of the catalyst acid with 1.57 g of (50% strength) aqueous sodium hydroxide solution Esterification of the excess methacrylic anhydride with 9.7 g of methanol (0.3 mol) For the preparation of the 30% strength solution in MMA: 600 g of MMA

(172) Theoretical yield: 1354 g

(173) Procedure:

(174) The mixture was weighed out in full and then heated to 90° C. with stirring and introduction of air. The reaction time at 90° C. is 2 h. Cooling was then carried out, down to approximately 60° C., and the sodium hydroxide dissolved in water for neutralization of the catalyst sulfuric acid, and also the methanol for esterification of the unreacted methacrylic anhydride, were added. Stirring was subsequently carried out for 1 h at 60° C., and then 600 g of methyl methacrylate were added to the mixture with stirring. The resulting solution was cooled to room temperature with stirring, and filtered. The solution of 4-(methacryloyloxy)benzophenone in methyl methacrylate has the following composition, determined by gas chromatography (figures in wt %): 59.6% methyl methacrylate 11.0% methacrylic acid 2.53% 4-hydroxybenzophenone 2.62% 4-(acetoxy)benzophenone 24.1% 4-(methacryloyloxy)benzophenone

(175) The water content is 0.09%, the stabilizer content is 178 ppm of 2,4-dimethyl-6-tert-butylphenol. The Pt—Co colour index is 126 APHA. Thus, the content of the unreacted and also of the acetylated keto-functionalized aromatic phenol relative to the content of keto-functionalized aromatic methacrylate is high enough that in application significant amounts can migrate or negatively influence the properties of the polymer.

(176) Yield: 1348 g (99% of theory)