* All experimental methods are cited from the reference, please refer to the original source for details. We do not guarantee the accuracy of the content in the reference.
Reference：
[1] Chemical Communications, 2012, vol. 48, # 91, p. 11232 - 11234
[2] Journal of the American Chemical Society, 2013, vol. 135, # 34, p. 12861 - 12868
polymer, Mw 29900, Mn 15600, Mw/Mn 1.92 (GPC), monomer units ratio 100:0.1; monomer(s): N-isopropylmethacrylamide; (8-methoxy-2-oxo-2H-benzo[g]chromen-4-yl)methyl acrylate[ No CAS ]
EXAMPLE 14 Preparation of Allyl Dimethylamine and N-isopropyl Methacrylamide A mixture of allyl chloride (76.5 g) and water (50 ml) is stirred at 20 C. and 3-dimethylamino-2-methyl-N-isopropylpropanamide (175 g, prepared in example 13) is added in portions keeping the temperature below 30 C. When addition is complete the mixture is stirred for 16 hours to give a viscous clear solution of allyl chloride quaternary amonium salt 46% caustic soda solution (87 g) is added and the mixture stirred at 20-25 C. for 3-4 hours. During this time N-isopropylmethacrylamide separates as a white crystalline solid, Allyldimethylamine can be recovered by distillation from the reaction mixture. N-isopropyl methacrylamide is recovered by filtration of the mixture remaining after distillation of the allyldimethylamine. The filtered solid is washed with water and dried in air to give N-isopropylmethacrylamide as a crystalline solid mp 89-91 C.
EXAMPLE 12 200 g of methyl methacrylate and 142 g of isopropylamine were heated at 190 C. for 21/2 hours in a 0.5-liter stirred autoclave (pmax =15 atmospheres). N-isopropyl-methacrylic acid amide was formed in this way in a 32% yield. If the same reaction is carried out in the presence of 2 g of HCl, N-isopropylmethacrylic acid amide is obtained in a 51% yield. Selectivity: greater than 90%.
With 2,2'-azobis(isobutyronitrile) In N,N-dimethyl-formamide at 60℃; for 18h;
84
Along with 0.64 g (6 mmole) of N-isopropyl methacrylamide (same as above), 0.57 g (5 mmole) of N-isopropylacrylamide (same as above), 26.7 mg (0.10 mmol) of ethyl 2-dimethylstibanyl-2-methylpropionate prepared in Example 1, 16.4 mg (0.10 mmol) of 2,2'-azobis(isobutyronitrile) and 3 ml of N,N-dimethylformamide (DMF) were placed into a glove box with the inside air replaced by nitrogen, followed by stirring at 60 °C for 18 hours. After the completion of the reaction, the reaction mixture was dissolved in 3 ml of chloroform, and the solution was then poured into 200 ml of hexane which was being stirred. The resulting polymer precipitate was collected by suction filtration and dried to obtain poly(N-isopropylmethacryl amide-r-N-isopropylacrylamide) (yield 95%). GPC analysis [with reference to the molecular weight of an authentic sample of poly(methyl methacrylate)] revealed Mn=24,100 and PD=1.39.
poly(N-(methacryloyloxy)succinimide-co-N-isopropylmethacrylamide)[ No CAS ]
Yield
Reaction Conditions
Operation in experiment
60.6%
With 2,2'-azobis(isobutyronitrile); In tert-butyl alcohol; at 80℃; for 20.0h;
N-(Methacryloyloxy)succinimide (2.745 g; 15 mmol), N-isopropylmeth-acrylamide (19.05 g; 150 mmol) and AiBN (83.9 mg; 0.5 mmol) were stirred in degassed tert-butanol (100 ml) under argon at 80 C. for 20 hours. The precipitate was filtered off and the filtrate was dropped slowly in hexane (1.8 1) to precipitate the polymer. The product was isolated by filtration. Yield: 13.2 g (60.6%) after drying in high vacuum.
With sodium hydroxide; In water; at 5 - 30℃; for 2.0h;Cooling with ice bath;
The following experiment utilized aqueous reaction conditions to produce N-isopropyl methacrylamide (IPMA):32 grams of water was added to a 250 mL, three-necked resin flask equipped with a mechanical stirrer, condenser and thermocouple. The water was cooled to 5-9 C. via an ice bath. 6 grams of isopropylamine was slowly added to the cooled water while mixing.The following components were added to the cooled, stirring isopropylamine solution separately and simultaneously via two separate syringe pumps: 1) methacrylic anhydride (16.53 g of 94% purity) and 2) a 50 wt. % aqueous solution of sodium hydroxide (8.12 g). The methacrylic anhydride and sodium hydroxide solution were each added over a one hour period while keeping the reaction temperature below 30 C. During this time, a precipitate formed in the reaction mixture. After all of the reagents were added, the reaction mixture was allowed to stir for one additional hour, and then the reactor contents were filtered. After drying the recovered solid under vacuum, 10.7 g product (LPMA) was obtained. Nuclear magnetic resonance (NMR) analysis revealed a product comprised of 93% IPMA, 4% water, and 3% impurities.
With TEMPOL; 2,6-di-tert-butyl-4-methyl-phenol; at -5 - 40℃; under 975.0980000000001 Torr; for 0.25h;Inert atmosphere; Large scale;
EXAMPLE 1 The preparation of N-isopropylmethacrylamide (NIPMAA) is carried out as shown in FIG. 1. 800 kg of methacrylic anhydride are placed in the stirred reactor (1) and, after mixing with 135 g of 4-methyl-2,6-di-tert-butylphenol and 115 g of 4-hydroxy-2,2,6,6-tetramethylpiperidin-1-oxyl, precooled to -5 C. The reactor (1) is flushed with nitrogen. The pressure regulator is set to 1.3 bar. 437 kg of 70% strength isopropylamine solution are pumped by means of the pump (2) into the reservoir (4) which can be cooled. The isopropylamine is introduced into the reactor (1) via the metering pump (3) in such a way that the reaction temperature is in the range from -5 to 40 C. during the reaction. The contents of the reactor are circulated via the heat exchanger (6) by means of the pump (5) during the reaction. The heat of reaction is removed by brine cooling (7) of the reactor (1) and the heat exchanger (6). After all the isopropylamine has been added, an after-reaction is carried out for 15 minutes at 20-40 C., preferably at 35-40 C. The slurry of NIPMAA in methacrylic acid formed after the reaction is diluted with 1100 kg of deionized water (demineralized water) to reduce the viscosity. The diluted mixture is transferred by means of the pump (5) to the stirred vessel (8) and neutralized by means of 355 kg of 25% strength ammonia solution while stirring. The major part of the NIPMAA precipitates in the neutralization, while the ammonium methacrylate formed remains in solution. To separate off the NIPMAA, the suspension is drained via the buffer reservoir (9) which serves for buffering the crystal slurry. The buffer reservoir (9) is cooled (to max. -5 C.). The buffered suspension is introduced via the mill (10) into the centrifuge (11). Cold deionized water (5 C.) which is used for washing the crystals in the centrifuge (11) in order to obtain the necessary purity is provided via the deionized water container (14). The aqueous mother liquor, which contains mainly ammonium methacrylate in addition to NIPMAA, is pumped by means of the pump (12) back into (8) or (9). At the end of the centrifugation, all of the mother liquor is collected in the vessel (13). The yield of NIPMAA in the NIPMAA reservoir (15) is 84%, based on methacrylic anhydride.
poly(N-isopropylacrylamide-co-N-isopropylmethacrylamide)[ No CAS ]
Yield
Reaction Conditions
Operation in experiment
93%
With methyl 2-dimethylbismuthanyl-2-methylpropanoate; 2,2'-azobis(isobutyronitrile); In N,N-dimethyl-formamide; at 60℃; for 24.0h;Product distribution / selectivity;
Along with 0.57 g (5 mmole) of N-isopropylacrylamide (same as above), 0.64 g (5 mmole) of <strong>[13749-61-6]N-isopropylmethacrylamide</strong> (Wako Pure Chemical Ind. Ltd.), 34.0 mg (0.10 mmole) of methyl 2-dimethylbismuthanyl-2-methylpropionate (Bi initiator) prepared in Example 1, 3.3 mg (0.02 mmole) of 2,2'-azobis-isobutyronitrile (same as above) and 1 ml of DMF were placed into a glove box with the inside air replaced by nitrogen, followed by stirring at 60 C for 24 hours. After the completion of the reaction, the reaction mixture was dissolved in 10 ml of tetrahydrofuran, and the solution was then poured into 200 ml of methanol which was being stirred. The resulting polymer precipitate was collected by suction filtration and dried to obtain 1.12 g (yield 93%) of poly(N-isopropylacrylamide-r-<strong>[13749-61-6]N-isopropylmethacrylamide</strong>) random copolymer. GPC analysis with reference to the molecular weight of an authentic sample of polystyrene revealed Mn=17000 and PD=1.37.
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