Method for producing glycerol carbonate methacrylate

(12) United States Patent Schmitt et al. US007414147B2 US 7,414,147 B2 Aug. 19,2008 (10) Patent No.: (45) Date of Patent: (54) (75) (73) (*) (21) (22) (86) (87) (65) (30) NOV. 26, 2003 (51) (52) (58) METHOD FOR PRODUCING GLYCEROL CARBONATE METHACRYLATE Inventors: Bardo Schmitt, Mainz (DE); Maik Caspari, Alsbach-Haehnlein (DE) Roehm GmbH & Co. KG, Darmstadt (DE) Assignee: Notice: Subject to any disclaimer, the term of this patent is extended or adjusted under 35 U.S.C. 154(b) by 49 days. Appl. No.: 10/580,840 PCT Filed: Aug. 24, 2004 PCT No.: PCT/EP2004/009423 § 371 (C)(1), (2), (4) Date: May 26, 2006 PCT Pub. No.: WO2005/058862 PCT Pub. Date: Jun. 30, 2005 Prior Publication Data US 2007/0106044 A1 May 10, 2007 Foreign Application Priority Data (DE) .............................. .. 103 55 830 Int. C1. C0 7D 31 7/36 C08G 65/02 (2006.01) C08L 67/00 (2006.01) U.S. Cl. .................................................... .. 560/217 Field of Classification Search ..................... .. None See application file for complete search history. (2006.01) (56) References Cited U.S. PATENT DOCUMENTS 2,979,514 A 4/1961 O’Brien et 211. 4,202,990 A 5/1980 Murakami et al. 4,423,235 A 12/1983 Burgard et al. 4,767,620 A * 8/1988 Mauz et al. .............. .. 525/54.1 4,772,666 A * 9/1988 Just et al. .................. .. 525/185 4,882,391 A 11/1989 Brindoepke et al. 5,374,699 A 12/1994 Iwamura et al. 6,936,734 B2 8/2005 Schmitt et al. 2004/0249191 A1 12/2004 Schmitt et al. FOREIGN PATENT DOCUMENTS DE 3937116 5/1991 EP 0 001 088 3/1979 EP 0 236 994 9/1987 EP 0 328 150 8/1989 EP 0 837 049 4/1998 EP 0 908 905 4/1999 EP 1 201 640 5/2002 FR 2 539 740 7/1984 FR 2 747 596 10/1997 JP 03 156803 7/1991 JP 2000 040526 2/2000 JP 2003 327854 11/2003 W0 03 022796 3/2003 * cited by examiner Primary Examiner—YVonne Eyler Assistant Examiner—YeVegeny Valenrod (74) Attorney, Agent, or Firm—Oblon, Spivak, McClelland, Maier & Neustadt, P.C. (57) ABSTRACT The invention relates to a method for producing glycerol carbonate methacrylate in the presence of metal-chelate cata- lysts of the metal ion-1,3-diketonate type. 11 Claims, No Drawings US 7,414,147 B2 1 METHOD FOR PRODUCING GLYCEROL CARBONATE METHACRYLATE The invention relates to a process for preparing glycerol carbonate methacrylate in the presence of metal chelate cata- lysts of the metal ion 1,3-diketonate type, especially zirco- nium acetylacetonate. In the coatings industry (2-oxo-1,3-dioxolan-4-yl)-methyl methacrylate (glycerol carbonate methacrylate) is a much- used crosslinker. There are a variety of preparation processes known for glycerol carbonate methacrylate. JP 2001018729 reacts glycerol carbonate with acryloyl chloride. The chloride wastes produced constitute a large environmental burden. WO 2000031195 reacts glycidyl methacrylate with CO2. This process is carried out under high pressure. The apparatus needed for the process is intricate and expensive. DE 3937116 reacts a cyclocarbonate-contaimng alcohol with a carboxylic acid at elevated temperature and in the presence of an acidic catalyst. The desired product is obtained, after distillation, in a purity of 75.5%. The yield varies, as a function of the acid used, between 25.5% and 83%. With the purity achieved therein, of just 75.5%, there are numerous applications in which the product carmot be used. It was an object of the invention to prepare glycerol car- bonate methacrylate in high purity and with high yields. This object has been achieved by a process for preparing (2-oxo-1,3-dioxolan-4-yl)methyl methacrylate in which methyl methacrylate is transesterified with glycerol carbon- ate in the presence of stabilizers and a metal chelate catalyst of the metal ion 1,3-diketonate type, especially zirconium acetylacetonate. Surprisingly it has been found that through the use of zirconium acetylacetonate as a catalyst it is possible to oper- ate under very mild conditions. The trans-esterification in the presence of zirconium acetyl-acetonate takes place at 50-80° C., preferably at 70° C. Zirconium acetylacetonate is used preferably in amounts of 0.1-5.0% by weight, more preferably of from 1.0-3.0% by weight, based on the total weight of the batch. As the catalyst it is possible, besides zirconium acetylac- etonate, to use other metal 1,3-diketonates as well, such as lithium or zinc 1,3-diketonates, for example, or 1,3-diphenyl- propane-1,3 -dione. It has been found that through the reaction regime of the invention a low crosslinker content is obtained. The effect of a low crosslinker content in applications is that improved mechanical properties are obtained in the case of copolymer- ization with other monofunctional monomers. The material is less brittle. Crosslinkers observed include glycerol dimethacrylate and glycerol trimethacrylate. The amount of crosslinker observed in the product is preferably less than 5% by weight, more preferably less than 3% by weight. Additionally it has been found that the product can be prepared with high yields and in high purity. Yields above 80% are obtained, with product purities of around 90%. The purities achieved mean that costly and inconvenient distilla- tive purification is unnecessary. The monomer possesses a high boiling point and can therefore be separated off only in a high vacuum. Costly and intricate distillation apparatus, and the risk of polymerization under the high thermal load, which is frequently observed with this monomer, both disappear. In the preparation of (2-oxo-1,3-dioxolan-4-yl)methyl methacrylate, stabilizers are added, which prevent free-radi- cal polymerization of the (meth)acrylic groups during the reaction. These stabilizers are widely known in the art. 5 10 15 20 25 30 35 40 45 50 55 60 65 2 Use is made principally of 1,4-dihydroxybenzenes. Differ- ently substituted dihydroxybenzenes, though, can also be employed. In general such stabilizers can be represented by the general formula (I) R5, (1) in which R5 is a linear or branched alkyl radical having one to eight carbon atoms, halogen or aryl, preferably an alkyl radical having one to four carbon atoms, more preferably methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert- butyl, Cl, F or Br; o is an integer in the range from one to four, preferably one or two; and R6 is hydrogen, a linear or branched alkyl radical having one to eight carbon atoms or aryl, preferably an alkyl radical having one to four carbon atoms, more preferably methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl or tert- butyl. An alternative is to use compounds having 1,4-benzo- quinone as their parent compound. Such compounds can be described by the formula (II) 0% _|_ R5, (11) in which R5 is a linear or branched alkyl radical having one to eight carbon atoms, halogen or aryl, preferably an alkyl radical having one to four carbon atoms, more preferably methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert- butyl, Cl, F or Br; and o is an integer in the range from one to four, preferably one or two. Also used are phenols of the general structure (III) (III) H0 in which R5 is a linear or branched alkyl radical having one to eight carbon atoms, aryl or aralkyl, propionic esters with mono- to tetrahydric alcohols, which may also contain heteroatoms such as S, O and N, preferably an alkyl radical having one to US 7,414,147 B2 3 four carbon atoms, more preferably methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl or tert-butyl. A further advantageous class of sub stance is represented by hindered phenols based on triazine derivatives of the formula (IV) (IV) 0 7 7 R )J\/R \N N AA 0 N 0 R7 where R7:compound of the formula (V) R8 (CPHZP) C OH in which (V) R8:CPH2P+1 where p:1 or 2. Employed with particular success are the compounds 1, 4-dihydroxybenzene, 4-methoxyphenol, 2,5-dichloro-3,6- dihydroxy-1,4-benzoquinone, 1,3,5-trimethyl-2,4,6-tris(3,5- di-tert-butyl-4-hydroxybenzyl)benzene, 2,6-di-tert-butyl-4- methylphenol, 2,4-dimethyl-6-tert-butyl-phenol, 2,2-bis[3, 5 -bis(1 ,1 -dimethylethyl) -4 -hydroxy-phenyl-1 - oxopropoxymethyl)]1,3-propanediyl ester, 2,2‘-thiodiethyl bis[3-(3,5-di-tert-butyl-4-hydroxy-phenyl)]propionate, octa- decyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, 3,5- bis(1 ,1 -dimethylethyl-2,2-methylenebis(4-methyl-6-tert-bu- tyl)phenol, tris (4-tert-butyl-3 -hydroxy-2, 6-dimethylbenzyl)-s-triazine-2,4,6-(1H,3H,5H)trione, tris (3,5-di-tert-butyl-4-hydroxy)-s-triazine-2,46-(1H,3H,5H) trione or tert-butyl-3,5-dihydroxybenzene, more preferably 4-hydroxy-2,2,6,6-tetramethylpiperidinooxyl, hydro- quinone, 4-methyl-2,6-di-tert-butylphenol, hydroquinone mono-methyl ether, 2-tert-butyl-6-(3-tert-butyl-2-hydroxy- 5-methylbenzyl)-4-methylphenyl acrylate, 4-(methacryloyl- oxy)-2,2,6,6-tetramethylpiperidine-1-oxyl or 2,5-di-tert-bu- tylhydroquinone. For the purposes of the invention a tocopherol compound is used to stabilize ethylenically unsaturated monomers. The tocopherol compounds which can be used in the con- text of the invention are chroman-6-ols (3,4-di-hydro-2H-1- benzopyran-6-ols) which are substituted in position 2 by a 4,8,12-trimethyltridecyl radical. The tocopherols which can be used with preference in accordance with the invention include alpha-tocopherol, beta-tocopherol, gan1rna-toco- pherol, delta-tocopherol, zeta2-tocopherol, and eta-toco- pherol, all of the aforementioned compounds each in the (2R,4'R,8'R) form, and also alpha-tocopherol in the (all-rac) form. Preference is given to alpha-tocopherol in the (2R, 4'R,8'R) form (trivial name: RRR-alpha-tocopherol), and also to the synthetic racemic alpha-tocopherol (all-rac-alpha- 10 15 20 25 30 35 40 45 50 55 60 65 4 tocopherol). Of these, in tum, the latter is of particular interest owing to the relatively low price. Based on the weight of the reaction mixture as a whole, the fraction of the stabilizers, individually or as a mixture, is generally 0.01%-0.50% by weight, the stabilizer concentra- tion being selected preferably so as not to be detrimental to the color number in accordance with DIN 55945. Many of these stabilizers are available commercially. Glycerol carbonate methacrylate can be used as a func- tional monomer in copolymers of coating materials and adhe- sives, and allows a subsequent, polymer-analogous reaction, including crosslinking with difunctional amines in a coating formulation. Furthermore, it can be used in battery electro- lytes, in extrusion resins, and for metal extraction. The examples given below are given in order better to illustrate the present invention, but have no capacity to restrict the invention to the features disclosed herein. EXAMPLES Example 1 118 g (1.0 mol) of glycerol carbonate are heated with 600 g (6.0 mol) of methyl methacrylate and 0.14 g of 4-hydroxy- 2,2,6,6-tetramethylpiperidinooxyl (Tempol) in a round-bot- tomed flask with distillation apparatus. Any water present is distilled off azeotropically with methyl methacrylate. The mixture is then cooled slightly. 18.0 g of zirconium acetylac- etonate and the amount of methyl methacrylate equivalent to the azeotrope distillate are added to the mixture. The mixture is heated to boiling. Alcoholysis is commenced at an over- head temperature of 70° C. Toward the end of the reaction it increased to 100° C. After the end of the alcoholysis the mixture is cooled and the zirconium acetylacetonate catalyst is precipitated with dilute phosphoric acid. The suspension is then pas sed through a pressure filter and the filtrate is separated off. For the purpose of separating off the glycerol carbonate, the filtrate is shaken in a separating furmel containing a dilute NaCl solution. The filtrate is degassed on a rotary evaporator at 70° C. and 200-10 mbar. The yield is 80.6%. The purity of the product is 91.4%. Experiment number: B1 Example 2 236 g (2.0 mol) of glycerol carbonate are heated with 1200 g (12.0 mol) of methyl methacrylate and 0.29 g of 4-hydroxy- 2,2,6,6-tetramethylpiperidinooxyl (Tempol) in a round-bot- tomed flask with distillation apparatus. Any water present is distilled off azeotropically with methyl methacrylate. The mixture is then cooled slightly. 28.7 g of zirconium acetylac- etonate and the amount of methyl methacrylate equivalent to the azeotrope distillate are added to the mixture. The mixture is heated to boiling. Alcoholysis is commenced at an over- head temperature of 70° C. Toward the end of the reaction it increased to 100° C. After the end of the alcoholysis the mixture is cooled and the zirconium acetylacetonate catalyst is precipitated with dilute phosphoric acid. The suspension is then pas sed through a pressure filter and the filtrate is separated off. For the purpose of separating off the glycerol carbonate, the filtrate is shaken in a separating furmel containing a dilute NaCl solution. The filtrate is degassed on a rotary evaporator at 70° C. and 200-10 mbar. The yield is 87.4%. The purity of the product is 89.7%. Experiment number: B2 US 7,414,147 B2 5 Comparative Example 1 Isopropyl Titanate 236 g (2.0 mol) of glycerol carbonate are heated with 600 g (6.0 mol) of methyl methacrylate and 0.14 g of 4-hydroxy- 2,2,6,6-tetramethylpiperidinooxyl (Tempol) in a round-bot- tomed flask with distillation apparatus. Any water present is distilled off azeotropically with methyl methacrylate. The mixture is then cooled slightly. 8.4 g of isopropyl titanate and the amount of methyl methacrylate equivalent to the azeo- trope distillate are added to the mixture. The mixture is heated to boiling. Alcoholysis is commenced at an overhead tem- perature of 70° C. The reaction, however, is very sluggish, and is therefore terminated after 3 hours, with excess methyl methacrylate (MMA) being removed by distillation. The crude ester is analyzed. Experiment number: C1 Comparative Example 2 Dioctyltin Oxide 118 g (1.0 mol) of glycerol carbonate are heated with 600 g (6.0 mol) of methyl methacrylate and 0.14 g of 4-hydroxy- 2,2,6,6-tetramethylpiperidinooxyl (Tempol) in a round-bot- tomed flask with distillation apparatus. Any water present is distilled off azeotropically with methyl methacrylate. The mixture is then cooled slightly. 14.4 g of dioctyltin oxide and the amount of methyl methacrylate equivalent to the azeo- trope distillate are added to the mixture. The mixture is heated to boiling. However, the reaction does not start, no methanol is formed, and the experiment is terminated. Experiment number: C2 Comparative Example 3 LiOH/CaO 118 g (1.0 mol) of glycerol carbonate are heated with 600 g (6.0 mol) of methyl methacrylate and 0.14 g of 4-hydroxy- Crude ester containing MMA Alcohol Product HS1 Catalyst Amount based on Experiment batch in % area % area % B1 Zirconium 8.2 70.1 acetylacetonate 2.5 B2 Zirconium 8.1 72.7 acetylacetonate 2.0 C1 Isopropyl 90.7 6.5 titanate 1.0 C2 Dioctyltin oxide# n.d. n.d. 2.0 C3 LiOH/CaO 7.5 49.5 2.0 C4 Lithium methoxide 2.2 68.9 2.5 Key: *GC: further peaks disregarded HS1 glycerol dimethacrylate HS2 glycerol trimethacrylate #no conversion n.d. not determined 10 15 20 25 30 35 6 2,2,6,6-tetramethylpiperidinooxyl (Tempol) in a round-bot- tomed flask with distillation apparatus. Any water present is distilled off azeotropically with methyl methacrylate. The mixture is then cooled slightly. 4.0 g ofLiOH, 10.4 g ofCaO, and the amount of methyl methacrylate equivalent to the azeotrope distillate are added to the mixture. The mixture is heated to boiling. Alcoholysis is commenced at an overhead temperature of 70° C. Toward the end of the reaction it increased to 100° C. Subsequently the batch is cooled and passed through a pressure filter, and the filtrate is separated off. For the purpose of separating off the glycerol carbonate, the filtrate is shaken in a separating furmel containing a dilute NaCl solution. The filtrate is degassed on a rotary evaporator at 70° C. and 200-10 mbar. The yield is 79.6%. The purity of the product is 52.7%. Experiment number: C3 Comparative Example 4 Lithium Methoxide 118 g (1.0 mol) of glycerol carbonate are heated with 600 g (6.0 mol) of methyl methacrylate and 0.14 g of 4-hydroxy- 2,2,6,6-tetramethylpiperidinooxyl (Tempol) in a round-bot- tomed flask with distillation apparatus. Any water present is distilled off azeotropically with methyl methacrylate. The mixture is then cooled slightly. 14.4 g of lithium methoxide and the amount of methyl methacrylate equivalent to the azeotrope distillate are added to the mixture. The mixture is heated to boiling. Alcoholysis is commenced at an overhead temperature of 70° C. Toward the end of the reaction it increased to 100° C. After the end of the reaction, excess MMA is removed by distillation. The crude ester is filtered and then analyzed. Experiment number: C4 The results of the experiments are summarized in the table below: Monomer pure GC :* HS2 Polytest Yield Alcohol Product HS1 HS2 area % area % in MeOH % ofth. area % area % area % area % 0.8 0.6 clear 80.6 0.9 91.4 0.9 0.9 0.9 0.9 clear 87.4 0.8 89.7 1.0 1.3 n.d. n.d. n.d. n.d. n.d. n.d. n.d. n.d. n.d. n.d. n.d. n.d. n.d. n.d. n.d. n.d. 12 25 clear 79.6 0.3 52.7 12.3 27.3 1.6 20 n.d. n.d. n.d. n.d. n.d. n.d. US 7,414,147 B2 7 The invention claimed is: 1. A process for preparing (2-oxo-1,3-dioxolan-4-yl)me- thyl methacrylate, comprising: transesterifying methyl methacrylate with glycerol car- bonate in the presence of stabilizers and a metal chelate catalyst of the metal ion 1,3-diketonate type, precipitating the catalyst, and separating off a filtrate. 2. The process for preparing (2 -oxo- 1 ,3 -dioxolan-4 -yl)me- thyl methacrylate, according to claim 1 wherein the metal chelate catalyst is zirconium acetylacetonate. 3. The process for preparing (2 -oxo- 1 ,3 -dioxolan-4 -yl)me- thyl methacrylate, according to claim 1 wherein the transes- terifying methyl methacrylate with glycerol carbonate takes place at 50-80° C. 4. The process for preparing (2 -oxo- 1 ,3 -dioxolan-4 -yl)me- thyl methacrylate, according to claim 3, wherein the transes- terifying methyl methacrylate with glycerol carbonate takes place at 70° C. 5. The process for preparing (2 -oxo- 1 ,3 -dioxolan-4 -yl)me- thyl methacrylate, according to claim 2 wherein zirconium acetylacetonate comprises 0.1-5.0% by weight, based on the total weight of the batch. 10 15 20 8 6. The process for preparing (2-oxo-1,3-dioxolan-4-yl)me- thyl methacrylate, according to claim 5 wherein zirconium acetylacetonate comprises 1.0-3.0% by weight, based on the total weight of the batch. 7. The process for preparing (2-oxo-1,3-dioxolan-4-yl)me- thyl methacrylate, according to claim 1 wherein an amount of crosslinker formed during the preparation is less than 5% by weight. 8. The process for preparing (2-oxo-1,3-dioxolan-4-yl)me- thyl methacrylate, according to claim 1 comprising stabiliz- ers in amounts of 0.01-0.50% by weight. 9. The process for preparing (2-oxo-1,3-dioxolan-4-yl)me- thyl methacrylate, according to claim 7 wherein the amount of crosslinker formed during the preparation is less than 3% by weight. 10. The process according to claim 1, wherein the precipi- tating the catalyst comprises adding dilute phosphoric acid. 11. The process according to claim 1, wherein the separat- ing off the filtrate comprises passing a suspension of a pre- cipitated mixture through a pressure filter.