METHOD FOR PRODUCING GLYCEROL MONO(METH)ACRYLATE

Abstract

The invention relates to a method for producing glycerol mono(meth)acrylate from 2,2-dimethyl-1,3-dioxolan-4-ylmethyl (meth)acrylate by acid-catalysed reaction with methanol.

Claims

1-14. (canceled)

15. A method for producing glycerol mono(meth)acrylate, comprising reacting 2,2-dimethyl-1,3-dioxolan-4-ylmethyl (meth)acrylate with methanol in the presence of an acidic silicate catalyst.

16. The method of claim 15, wherein the silicate in said acidic silicate catalyst is a sheet silicate or a mixture of sheet silicates.

17. The method of claim 16, wherein the sheet silicate or the mixture of sheet silicates have a specific surface area greater than 50 m.sup.2/g.

18. The method of claim 16, wherein the sheet silicate or the mixture of sheet silicates have a specific surface area greater than 320 m.sup.2/g.

19. The method of claim 16, wherein the sheet silicate or the mixture of sheet silicates is selected from the group consisting of: montmorillonite; kaolinite; hectorite; halloysite; and bentonite.

20. The method of claim 16, wherein the sheet silicate or the mixture of sheet silicates is montmorillonite or bentonite.

21. The method of claim 15, wherein the reaction is performed in anhydrous manner and the product is anhydrous glycerol mono(meth)acrylate.

22. The method of claim 15, wherein the acidic silicate catalyst is present in an amount of from 1% by weight to 15% by weight, based on the reaction batch.

23. The method of claim 15, further comprising at least one stabilizer selected from the group consisting of: octadecyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate; phenothiazine, hydroquinone; hydroquinone monomethyl ether; 4-hydroxy-2,2,6,6-tetramethylpiperidin-ooxyl (TEMPOL); 2,4-dimethyl-6-tert-butylphenol; 2,6-di-tert-butylphenol; 2,6-di-tert-butyl-4-methylphenol; para-substituted phenylenediamines; 1,4-benzoquinone; 2,6-di-tert-butyl-alpha-(dimethylamino)-p-cresol; and 2,5-di-tert-butylhydro-quinone.

24. The method of claim 23, wherein the total amount of stabilizer is between 0.001% by weight and 0.5% by weight.

25. The method of claim 23, wherein the stabilizers hydroquinone monomethyl ether and hydroxy-2,2,6,6-tetramethylpiperidinooxyl (TEMPOL) are used in combination.

26. The method of claim 25, wherein the ratio of hydroquinone monomethyl ether to TEMPOL is in the range of 10:1 and 4:1.

27. The method according of claim 15, wherein the reaction temperature is between 20° C. and 80° C.

28. The method of claim 27, wherein the reaction temperature is between 40° C. and 70° C.

29. Glycerol mono(meth)acrylate comprising a content of glycerol di(meth)acrylate of less than 1% and a content of glycerol of less than 1%.

30. The method of claim 18, wherein the sheet silicate or the mixture of sheet silicates is selected from the group consisting of: montmorillonite; kaolinite; hectorite; halloysite; and bentonite.

31. The method of claim 30 wherein the sheet silicate or the mixture of sheet silicates is selected from the group consisting of: montmorillonite and bentonite.

32. The method of claim 31, wherein the reaction is performed in anhydrous manner and the product is anhydrous glycerol mono(meth)acrylate.

33. The method of claim 31, wherein the acidic silicate catalyst is present in an amount of from 1% by weight to 15% by weight, based on the reaction batch.

34. The method of claim 33, further comprising at least one stabilizer selected from the group consisting of: octadecyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate; phenothiazine; hydroquinone; hydroquinone monomethyl ether; 4-hydroxy-2,2,6,6-tetramethylpiperidin-ooxyl (TEMPOL); 2,4-dimethyl-6-tert-butylphenol; 2,6-di-tert-butylphenol; 2,6-di-tert-butyl-4-methylphenol; para-substituted phenylenediamines; 1,4-benzoquinone; 2,6-di-tert-butyl-alpha-(dimethylamino)-p-cresol; and 2,5-di-tert-butylhydro-quinone.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0023] The invention relates to both glycerol monomethacrylate (GMMA) and glycerol monoacrylate (GMA). Accordingly, the term glycerol mono(meth)acrylate, as used in the context of this invention, includes both GMMA and GMA.

[0024] The ratio by weight of 2,2-dimethyl-1,3-dioxolan-4-ylmethyl (meth)acrylate to methanol in the method according to the invention should be in the range from 1:1 to 1:20, preferably from 1:1 to 1:15 and particularly preferably in the range from 1:1 to 1:4.

[0025] For the reaction, both technical-grade methanol and high purity methanol with a purity of 99.9% can be used.

[0026] Particularly suitable silicate catalysts include clay minerals such as montmorillonite, kaolinite, hectorite, halloysite or mixtures thereof, for example bentonite. Particular preference is given to using acidic sheet silicates and aluminium silicates, such as Tonsil® 312 FF or montmorillonite K10, K30 etc. The catalysts used are particularly particles with the greatest possible specific surface area, particularly with specific surface areas greater than 50 m.sup.2/g, preferably with a specific surface area greater than 220 m.sup.2/g, and particularly preferably with a specific surface area greater than 320 m.sup.2/g.

[0027] Compared to homogeneous-catalysed acetonide cleavage of 2,2-dimethyl-1,3-dioxolan-4-ylmethyl (meth)acrylate with p-TsOH (para-toluenesulfonic acid) or the heterogeneous-catalysed acetonide cleavage of 2,2-dimethyl-1,3-dioxolan-4-ylmethyl (meth)acrylate with acidic ion exchange resins (Amberlyst®), an exceptionally low-crosslinker glycerol mono(meth)acrylate product is obtained particularly when using silicate-based catalysts: contamination with glycerol di(meth)acrylate is less than 1%. The product is also virtually free of free glycerol (<1%), which is also found in greater amounts in conventional synthetic routes.

[0028] Preferably, the reaction is performed in anhydrous manner and the product is anhydrous glycerol mono(meth)acrylate.

[0029] The acidic silicate catalyst is used in an amount of 0.5% by weight to 20% by weight, preferably in an amount of 1% by weight to 15% by weight, and especially in an amount of approximately 10% by weight, based on the reaction batch.

[0030] Pre-treatment of the catalyst is generally not required.

[0031] For stabilizing the starting material and/or product, stabilizers/polymerization inhibitors may be used.

[0032] Preferred polymerization inhibitors that can be used include, inter alia, octadecyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate, phenothiazine, hydroquinone, hydroquinone monomethyl ether, 4-hydroxy-2,2,6,6-tetramethylpiperidinooxyl (TEMPOL), 2,4-dimethyl-6-tert-butylphenol, 2,6-di-tert-butylphenol, 2,6-di-tert-butyl-4-methylphenol, para-substituted phenylenediamines such as for example N,N′-diphenyl-p-phenylenediamine, 1,4-benzoquinone, 2,6-di-tert-butyl-alpha-(dimethylamino)-p-cresol and 2,5-di-tert-butylhydroquinone. These compounds can be used individually or in the form of mixtures and are generally commercially available. The mode of action of the stabilizers is usually that they act as free-radical scavengers for the free radicals that occur in the polymerization. Further details can be found in the relevant technical literature, particularly Römpp-Lexikon Chemie; publisher: J. Falbe, M. Regitz; Stuttgart, New York; 10th edition (1996); keyword “Antioxidantien” and the literature references cited therein.

[0033] The total amount of stabilizers used is between 0.0001% by weight and 0.5% by weight, preferably in the weight range between 0.001% by weight and 0.05% by weight.

[0034] Preferably, the stabilizers hydroquinone monomethyl ether and hydroxy-2,2,6,6-tetramethylpiperidinooxyl (TEMPOL) are used in combination. The ratio of hydroquinone monomethyl ether to TEMPOL is ideally in the range between 15:1 and 1:1, preferably in the range between 10:1 and 4:1.

[0035] In addition, gaseous oxygen can be used for stabilization. This can, for example, be in the form of air, in which the amounts introduced should be adjusted such that the content in the gas phase above the reaction mixture remains below the explosion limit.

[0036] The reaction times depend, inter alia, on the selected parameters such as pressure and temperature. In general, however, they are in the range from 1 to 65 hours, preferably 5 to 24 hours and especially preferably 5 to 22 hours. In the continuous processes, the residence times are generally in the range of 5 to 24 hours, preferably 5 to 22 hours.

[0037] The reaction can be carried out preferably while stirring, wherein the stirring speed is in the range of 50 to 2000 rpm and preferably in the range of 100 to 500 rpm.

[0038] The reaction is ideally carried out at standard pressure. The reaction temperature is between 20° C. and 80° C., preferably between 40° C. and 70° C.

[0039] The method according to the invention can be operated industrially, specifically both in continuous/semi-continuous mode and batchwise mode.

[0040] In comparison to the methods known from the literature, glycerol mono(meth)acrylate is obtained by the method according to the invention not only in anhydrous, but also in highly pure form.

[0041] The glycerol mono(meth)acrylate obtained by the method according to the invention can be used in applications which require a low residual water content or even the complete absence of water. In particular, it can be used in oil-based systems in the sector of lubricants and hydraulic oils, and in polymerization reactions in liquid and hydrophobic media.

[0042] The following examples illustrate the method according to the invention without these being limited thereto.

Examples

[0043] Apparatus: 500 ml stirring apparatus, air inlet, Büchi rotary evaporator with vacuum accessories, pressure filter. Magnetic stirrer, oil pump.

[0044] Reaction:

##STR00001##

TABLE-US-00001 50 g of 2,2-dimethyl-1,3-dioxolan-4-ylmethyl 0.25 mol methacrylate (IPGMA) = 80 g of methanol = 2.5 mol 0.016 g of hydroquinone monomethyl ether 400 ppm rel. to GMMA = 0.004 g of hydroxy-2,2,6,6-tetramethylpiperidinooxyl 100 ppm (TEMPOL); rel. to GMMA = 13 g of catalyst/Tonsil ® 312 FF standard 10% rel. to mixture =

[0045] Mixture:

[0046] Procedure:

[0047] The batch is boiled at 65° C. under reflux with stirring for 20 h. The GMMA crude ester obtained is filtered through a pressure filter with K800 filter layer. The filter is rinsed with ca. 100 g of methanol. The clear, pale yellow GMMA crude ester is freed of solvent at 50° C. bath temperature at 20 mbar on a rotary evaporator for 30 min.

[0048] Results:

TABLE-US-00002 GMMA GC-RV % by Reaction in area % weight Dura- Bottoms Mass Glycerol IPGMA MeOH rel. to tion max. g = % of dimeth- mol mol Catalyst mixture h ° C. theory MeOH IPG IPGMA Glycerol acrylate GMMA Remarks 1 0.25 2.5 Amberlyst ® 10 20 50 43 g = — 9.3 0.4 16.4 16.5 35.9 Clear A15 washed 38% dark and dried product LJ: 20896/57 2 0.25 2.5 p-TS 1 22 50 43 g = — 26.5 2.9 25.2 8.9 7.8 Clear  8% yellow product −> polymer 3 0.25 2.5 Montmoril- 10 22 50 41 g = 3.0 1.0 34.2 0.8 0.1 56.6 Clear lonite K10 58% yellow product 4 0.25 2.5 Montmoril- 10 5 50 41 g = 2.3 0.6 37.4 0.5 <0.1 58.0 Clear lonite K10 59% yellow product 5 0.25 2.5 Montmoril- 10 5 65 42 g = 0.1 1.1 26.1 1.6 0.1 65.3 Clear lonite K30 69% yellow product 6 0.25 2.5 Tonsil ® 10 22 50 41 g = 0.6 0.5 31.2 0.4 — 66.6 Clear 312 FF 68% pale yellow product 7 0.25 2.5 Tonsil ® 10 64 RT 44 g = 2.2 0.5 38.0 0.4 — 58.7 Clear 312 FF 65% pale yellow product 8 0.25 2.5 Tonsil ® 10 20 65 43 g = 2.3 0.5 22.3 0.6 <0.1 73.1 Clear 312 FF 79% pale yellow product