KR100435105B1 - Homogeneous Atom Transfer Radical Polymerization(ATRP) of Methyl Methacrylate(MMA) Using the Novel Catalysts Based on Carboximidate Ligand - Google Patents

Abstract

The present invention relates to a radical polymerization method of methyl methacrylate (MMA) based on atom transfer radical polymerization (ATRP), specifically based on carboxyimide ligand (Formula 2) Reversible oxidation-reduction of transition metal compounds (CuX / Formula 2; X = Cl, Br) induces reversible reaction of halogen atoms (X) between growing and dormant species, resulting in faster polymerization rates and narrower molecular weight distribution A method for producing a polymer. In the present invention, the radical polymerization of methyl methacrylate shows excellent properties when developed at low temperature by developing a new ligand different from the ligand described in the existing literature, and the method of synthesizing the ligand can reduce the cost. Therefore, the industrial value is high.

Formula 2

R ¹ , R ² , R ³ , R ⁴ , and R ⁵ in Chemical Formula 2 are the same as or different from each other, hydrogen, an alkyl group or an alkoxy group of C ₁ to C ₁₂ , an aryl group or an aryloxy group of C ₆ to C ₂₀ , and C _Is selected from a cycloalkyl group of ₆ to C ₂₀ and R ⁶ is selected from hydrogen, a C ₁ to C ₁₂ alkyl group, a C ₆ to C ₂₀ aryl group and a C ₃ to C ₂₀ cycloalkyl group as a substituent of a ligand.

Description

Homogeneous Atom Transfer Radical Polymerization (ATRP) of Methyl Methacrylate (MMA) Using the Novel Catalysts Based on Carboximidate Ligand}

The present invention relates to a polymerization method based on a carboxyimidate ligand, and has a halogen atom (X) between a growth species and a dormant species due to the reversible redox reaction of a transition metal compound (CuX / Formula 1; X = Cl, Br). The present invention relates to a method for preparing a methyl methacrylate polymer having a faster polymerization rate and a narrower molecular weight distribution by inducing a reversible reaction.

In general, radical polymerization offers the advantage that it can be used for the polymerization of a wide variety of commercially important monomers. Many of these monomers cannot be polymerized by other polymerization methods (anion, cationic polymerization, etc.). In addition, radical polymerization is easier to polymerize random polymers and block copolymers and can be carried out in bulk, solution, suspension and emulsion phases as compared to other polymerization methods.

However, because of the reaction between radicals, ordinary radical polymerizations tend to yield polymers having a heterogeneous and broad molecular weight distribution, and thus provide radicals which provide polymers having a predetermined molecular weight, narrow molecular weight distribution (low polydispersity) and controlled uniform structure. A polymerization method is required.

Living polymerization, on the other hand, makes it possible to produce various polymers that can be clearly defined in terms of molecular size, polydispersity, morphology, composition, functionalization and microstructure. Over the last 40 years many living systems have been developed based on anionic, cationic and several other initiators (O.W. Webster, Science, 251, 887 (1991)).

The most remarkable of these attempts to control molecular weight and polydispersity was based on the Atom Transfer Radical Polymerization (ATRP) proposed by Professor Matyjaszewski in 1995. It is a polymerization method of an alkene. It adds living properties to radicals and maintains very fast dynamic reactions in which the initial initiator or growth species radicals reversibly bond and dissociate with radical scavengers, thereby forming oligomers by pairing radicals together during polymerization. It is a method of obtaining a product having a uniform predetermined molecular weight by inhibiting a stop reaction and maintaining a constant concentration of growth species radicals during the reaction. The general accepted mechanism of ATRP is shown schematically in Formula 1.

[Formula 1]

As can be seen above, the transition metal compound (Mt ⁿ / L) used as a catalyst removes halogen from the initiator (RX) or dormant species (P _n -X) to form an oxidized form of X-Mt ^{n + 1} / L. The generated radical (R or P _n ·) reacts with the monomer to form RM ·, an intermediate of reaction, and X-Mt ^{n + 1} / L reacts with RM · again to form Pn-X, forming Mt ⁿ / L Reduced to. The rapid equilibrium reaction of the redox reaction of Mt ⁿ / Mt ^{n + 1} successfully suppresses the concentration of growth species radicals and keeps constant and low at all times, thereby significantly reducing the stop reaction due to pairing between radicals.

In ATRP, initiators induce a polymerization with better living properties by minimizing the difference between initiation rate and growth rate by using a halide compound having a chemical structure similar to that of a growing species radical. In addition, ATRP uses a metal catalyst complexed by a ligand, wherein the ligand used serves to increase the solubility of the metal catalyst in the solvent and to control the redox potential difference of the metal. Therefore, studies on the combination of transition metals and ligands that act as reaction catalysts have been actively conducted.

The system first attempted by Prof. Matyazevski was successfully utilized for radical polymerization of styrene using copper as a transition metal and bipyridine (2,2'-Bipyridine; bpy) as a ligand (K. Matyjaszewski, Macromolecules, 28, 7901 (1995))

Here, the apparent rate constant over time ( k _obs = -d (ln [M]) / d t) is constant, and the radical polymerization reaction is successful with almost no stop reaction by obtaining a product having a narrow molecular weight distribution after the reaction. It shows that it is done. In addition, the ATRP reaction of the various styrene derivatives investigated by Jian et al. Showed that the apparent polymerization rate was generally proportional to the concentration of monomers, so that the concentration of the growth species radical was kept constant, and the molecular weight increased in proportion to the monomer conversion rate.

In 1998, Prof. Matyazevsky also showed that methylmethacrylate was successfully polymerized by ATRP using Cu (I) X / ligand catalyst in 1998 (K. Matyjaszewski, Macromolecules, 31, 1527). 1998))

On the other hand, Sawamoto et al. Reported an ATRP reaction using RuCl ₂ (PPh ₃ ) ₃ catalyst. RuCl ₂ (PPh ₃ ) ₃ catalyst is a very effective catalyst for living radical polymerization of MMA, but it usually takes several days to complete the reaction. There is a problem that the reaction rate is very slow (M. Sawamoto, Macromolecules, 29, 1070 (1996); M. Sawamoto, Macromolecules, 28, 1721 (1995)).

In addition, ATRP of MMA using catalysts such as FeCl ₂ (PPh ₃ ) ₃ and NiBr ₂ (PPh ₃ ) ₂ has been reported.

ATRP also contains methyl acrylate (MA), 2-hydroxyethyl methacrylate, 4-vinylpyridine, and 2-dimethylamino ethyl methacrylate ((2 It is also applied to a wide variety of acrylic monomers such as -dimethylamino) ethyl methacrylate) and also to the polymerization of acrylonitrile (AN).

Recently, ATRP has been studied in various angles. An important area is the design of ligand. The ligand determines the atomic transfer equilibrium constant of the polymerization reaction and is related to the stability of the metal catalyst under different reaction conditions. Ligand's influence in ATRP can be classified into electronic effect, structural effect, and solubility. For example, if an electron withdrawing group is attached to a ligand as a substituent or a structural effect is large, the catalyst's reactivity decreases. In addition, the solubility of the metal catalyst changes depending on the substituents attached to the ligand, which shows a direct functional relationship to the reactivity of the catalyst (K. Matyjaszewski, Macromol. Rapid Commun., 20, 341 (1999)).

The most useful and most commonly used form is a ligand form containing nitrogen. It was first used as a ligand by Professor Matyazevsky in the form of bipyridine, and then in USP 5,854,364, the multidentate ligand form was also shown to be useful for the synthesis of vinyl monomers. The ACS symposium (K. Matyjaszewski, ACS Symp., 760, 207 (2000)) showed that the higher the number of coordination bonds, the more effective the ATRP reactivity was, and that the bridge or cyclic ligands were superior to linear ligands. . However, the ligands of the bipyridine derivative series introduced above are very difficult to synthesize most of them, which is not preferable when considering the cost aspect in industrial applications. Therefore, the development of a new ligand that maintains the efficacy of the existing ligand catalyst by a simple synthesis method is urgently needed.

Therefore, an object of the present invention is to polymerize the vinyl monomer methyl methacrylate (methyl methacrylate, MMA) using ATRP, the reaction system is too high (90 ℃ or more), or the reaction rate is too slow It is to provide a new method of polymerization of methyl methacrylate using atomic transfer radical polymerization based on the carboxyimidate ligand which can minimize the molecular weight distribution and suppress side reactions between radicals, which is an advantage of the existing ATRP while improving the disadvantages.

Another object of the present invention is to provide a technology that enables relatively simple and low-cost ligand synthesis by improving the difficulty in synthesizing the existing ligand and the cost problem in industrial application.

The present invention for achieving the above object in the polymerization of vinyl or diene monomers such as methyl methacrylate (MMA), styrene (ST), methacrylate (MA) by ATRP,

(a) preparing a catalyst represented by Formula 1 below; And

MA _a (L) _n

(M is Cu, A is halogen atom)

L is represented by the following Chemical Formula 2 as a ligand of Cu metal.

R ¹ , R ² , R ³ , R ⁴ , and R ⁵ in Formula 2 may be the same as or different from each other, hydrogen, an alkyl group or an alkoxy group of C ₁ to C ₁₂ , an aryl group or an aryloxy group of C ₆ to C ₂₀ , Selected from C ₃ to C ₂₀ cycloalkyl group, R ⁶ is selected from hydrogen, C ₁ to C ₁₂ alkyl group, C ₆ to C ₂₀ aryl group, C ₃ to C ₂₀ cycloalkyl group as substituent of the ligand.

(b) adding the ligand catalyst of step (a) to the monomer, stirring and adding the initiator to perform polymerization.

The amount of the ligand added is 2 times the molar ratio of the transition metal.

The temperature range is characterized in that 20 ℃ to 100 ℃.

The initiator is characterized in that the concentration is 0.5 to 2 times the molar ratio of the transition metal catalyst.

The monomer is characterized in that the concentration is 100 to 800 times the molar ratio of the transition metal catalyst.

1 is a graph related to the polymerization rate and its linearity for each ligand.

FIG. 2 is a graph of MMA maintaining linearity throughout the polymerization phase over a solution.

Figure 3 is a graph showing the result of polymerizing styrene in bulk by the catalyst presented in the present invention.

4 is a graph showing the polymerization result of methyl acrylate in bulk on the catalyst of the present invention.

Hereinafter, embodiments of the present invention will be described in detail.

In the present invention, CuX / (ligand) ₂ system was used, and alkyl pyridine-2-carboximidate was used as a ligand, and in particular, substituents of the ligand were methyl and isopropyl. The effect of ligand was analyzed by changing to cyclopentyl and n-octyl. As a result, it was found that the catalyst with cyclopentyl substituent had a great effect on the low temperature ATRP polymerization. In order to find the optimum condition of the reaction, polymerization was carried out in various solutions and in bulk, and the concentration of the initiator and the monomer was compared. By comparing and analyzing the effects of halide, the effect of halide, etc. The present invention was completed by showing that the results are much superior to the polymerization method of MMA using ATRP presented previously.

That is, the present invention is divided into two steps.

First, the synthesis of alkyl pyridine-2-carboximidate by substitution reaction of nitrile group and alcohol under base catalyst as preparation of ligand, which is shown in the formula (3).

In Formula 3, R ¹ , R ² , R ³ , R ⁴ , and R ⁵ are the same as or different from each other, hydrogen, an alkyl group or an alkoxy group of C ₁ to C ₁₂ , an aryl group or an aryloxy group of C ₆ to C ₂₀ , C ₆ -C ₂₀ cycloalkyl group, R ⁶ is selected from hydrogen, C ₁ -C ₁₂ alkyl group, C ₆ -C ₂₀ aryl group, C ₃ -C ₂₀ cycloalkyl group as a substituent of the ligand.

In the present invention, methyl, isopropyl, cyclopentyl and n-octyl were used. And it was confirmed that each ligand was successfully synthesized by ¹ H NMR and ¹³ C NMR. Each ligand binds to Cu to form a chelate compound, which acts as a polymerization catalyst for ATRP. Particularly, the methyl and isopropyl derivatives are partially dissolved. The cyclopentyl and n-octyl derivatives are completely dissolved in the system. Represents the efficiency of each catalyst.

In the second step, the reaction scheme is schematically shown as a polymerization step of MMA using an ATRP catalyst.

In the above Formula 4, the type of ligand, the reaction temperature, the concentration of the initiator and the monomer, and the type of the halide were set differently, and thus the most efficient reaction conditions were found.

The growth rate of the growth species according to the ATRP reaction mechanism is shown in the general formula (2).

[Formula 2]

Where R _p is the reaction rate, [M] _o is the initial monomer concentration, [M] is the remaining monomer concentration per polymerization time, and k _obs is the apparent rate constant. In the case of ATRP, the relationship of ln ([M] _o / [M]) to the polymerization time shows linearity, which shows that the concentration of growth species [P _n ㆍ] is always kept constant throughout the reaction. These results indicate that the polymerization reaction is a living radical polymerization reaction in which irreversible chain transfer or stop reaction is almost ignored. To evaluate the effective ligand catalyst, the apparent reaction rate constant ( k _obs = -d (ln [M]) / d t) was calculated and the number average molecular weight (M _n ) and molecular weight distribution (M _w / M) were calculated using GPC. _n ) was analyzed according to each ligand and reaction conditions. The ligand synthesized in the present invention was applied to the polymerization of other monomers (styrene, methyl acrylate) and compared with the results of MMA.

As mentioned before, the apparent reaction rate constants ( k _obs ; slope of the graph of ln ([M] _o / [M] vs time)) were compared with each other and the ligand catalysts having cyclopentyl substituents were 20-60 ° C. It maintains linearity at and is more than twice as fast as other ligands. Ligand catalyst of other substituents and normal diheptyl bipyridine (4-4'-di-n-heptyl-2,2-bipyridine; dHbpy) ligand catalyst, which has been widely used in the literature, cannot maintain linearity with polymerization time. It shows a curvature, indicating that [P.] gradually decreases due to the stop reaction between some radicals during MMA polymerization. In particular, in the present invention, the ligand catalyst having a cyclopentyl substituent showed a value of 1.14. This demonstrates that ligands with cyclopentyl substituents have very good efficacy in properly performing the function of ATRP catalysts in the narrow range of 1.12 to 1.20 for the polymerization of MMA and molecular weight distribution (M _w / M _n ). It is.

Preparation Example 1 Cyclopentyl pyridine-2-carboximidate (CpPCI) Ligand Synthesis

In a 500 mL round flask, sodium metal (0.30 g, 0.013 mol) was added to cyclopentanol (50 mL) in an inert gas atmosphere to completely dissolve at room temperature, and 2-cyanopyridine (12.5 mL, 0.13 mol) was added at room temperature. Stir for 12 hours. Thereafter, acetic acid (0.78 mL, 0.013 mol) was added thereto, stirred for 10 minutes, and brine (50 mL) was added thereto, and the solution was filtered with a separatory funnel. The solution is first evaporated in a rotary evaporator to obtain 2-cyanopyridine at 60 ° C. using a distillation apparatus under vacuum. The reaction was confirmed to be 75% yield using an NMR analyzer. ¹ H NMR (400.03 MHz, CDCl ₃ ) δ 9.17 (br s, 1H, NH), 8.63, 7.79, 7.34 (m, 4H, pyridine ring), 5.49 (m, 1H, OCH), 1.6, 2.1 (m, 4H, CH ₂ ); ¹³ C { ¹ H} NMR (100.6 MHz, CDCl ₃ ) δ 165.4, 148.8, 136.9, 124.9, 120.6 (pyridine ring), 147.8 (C = NH), 78.3 (OCH), 32.5, 23.7 (CH ₂ ); MS-FAB m / z = 191.1184 (MH ⁺ ).

Preparation Example 2 Isopropyl pyridine-2-carboximidate ( ⁱ PrPCI) ligand synthesis

In a 500 mL round flask, sodium metal (0.30 g, 0.013 mol) was added to 2-propanol (50 mL) in an inert gas atmosphere to completely dissolve at room temperature, followed by addition of 2-cyanopyridine (12.5 mL, 0.13 mol) to room temperature. Stir for 12 hours. Thereafter, acetic acid (0.78 ml, 0.013 mol) was added thereto, stirred for 10 minutes, and brine (50 ml) was added thereto, and the solution was filtered with a separatory funnel. The solution is first evaporated in a rotary evaporator to obtain 2-cyanopyridine at 60 ° C. using a distillation apparatus under vacuum. The reaction was confirmed to be 95% yield using an NMR analyzer. ¹ H NMR (400.03 MHz, CDCl ₃ ) δ 9.19 (br s, ¹ H, NH), 8.64, 7.80, 7.35 (m, 4H, pyridine ring), 5.37 (m, J = 6.2 Hz, 1H, OCH), 1.41 (d, J = 6.2 Hz, 6H, CH ₃ ); ¹³ C { ¹ H} NMR (100.6 MHz, CDCl ₃ ) δ 165.2, 148.9, 137.0, 125.0, 120.7 (pyridine ring), 147.9 (C = NH), 68.7 (OCH), 21.6 (CH ₃ ); MS-FAB m / z = 165.1028 (MH ⁺ ).

Preparation Example 3 Synthesis of n-octyl pyridine-2-carboximidate Ligand

To a 500 mL round flask, sodium metal (0.30 g, 0.013 mol) was added to 1-octanol (50 mL) in an inert gas atmosphere to completely dissolve at room temperature, followed by 2-cyanopyridine (12.5 mL, 0.13 mol) to room temperature. Stir for 12 hours. Thereafter, acetic acid (0.78 mL, 0.013 mol) was added thereto, stirred for 10 minutes, and then brine (50 mL) was added, and the solution was filtered with a separatory funnel. The solution is first evaporated in a rotary evaporator to obtain 2-cyanopyridine at 60 ° C. using a distillation apparatus under vacuum. The reaction was able to confirm the yield of 65% by using an NMR analyzer. ¹ H NMR (400.03 MHz, CDCl ₃ ) δ 9.16 (br s, 1H, NH), 8.62, 7.80, 7.38 (m, 4H, pyridine ring), 4.37 (t, J = 6.7 Hz, 2H, OCH ₂ ), 1.83 (quintet, J = 7.6 Hz, 2H, OCH ₂ C H ₂ CH ₂ ), 1.30 (m, 10H, CH ₂ ), 0.89 (t, J = 6.6 Hz, CH ₃ ); ¹³ C { ¹ H} NMR (100.6 MHz, CDCl ₃ ) δ 165.9, 148.8, 136.8, 124.9, 120.6 (pyridine ring), 147.4 (C = NH), 66.2 (OCH ₂ ), 31.5, 29.0, 28.4, 25.9, 22.3 (CH ₂ ), 13.8 (CH ₃ ); MS-FAB m / z = 235.1810 (MH ⁺ ).

Example 1 Effect of Ligands on Polymerization Kinetics and Molecular Weight Distribution

Proper amount of Cu ^I X (X = Cl, Br), the ligand obtained in Preparation Examples 1-3 and MMA (20.02 g, 0.20 mol) as monomer and 1,2-dimethoxybenzene (w / w = 1: 1) was placed in a 50 mL Schlenk flask. To avoid contact with air, this was done in a glove box. The flask was placed in an oil bath, mixed for 10 minutes at 60 ° C. under inert gas, and then an appropriate amount of initiator (ethyl 2-bromoisobutyrate; EB i B) was injected into the syringe. The molar ratio of each reactant is [CuBr] _o : [Ligand] _o : [EB i B] _o : [MMA] _o = 1: 2: 1: 400. Thereafter, samples were taken every 30 minutes, and then the apparent rate constant ( k _obs ) was determined by measuring the amount of monomer remaining unpolymerized by using an NMR analyzer, which is shown in FIG. 1. After 3 hours and 30 minutes, the reaction was terminated, and the polymer was precipitated in methanol solution and dried in a vacuum oven at a temperature of 60 ° C. Subsequently, the reactants were measured by molecular weight using a GPC analyzer to measure the number average molecular weight (M _n ) and molecular weight distribution (M _w / M _n ) of the polymerized MMA, and the most commonly used normal diheptyl bipyridine ( The results of 4,4'di-n-heptyl-2,2-bipyridine (dHbpy) were compared and analyzed, and the results are shown in Table 1.

Ligand Type % Conversion M _n M _w / M _n k _obs (10 ^-4 s ^-1 ) dHbpy 56 29,150 1.12 0.59 CpPCI 79 39,110 1.14 1.19 MePCI 48 44,830 1.20 0.47 ⁱ PrPCI 54 30,380 1.19 0.57 OctPCI 56 27,840 1.20 0.63

As a result of Example 1, the cyclopentyl pyridine-2-carboxyimidate (CpPCI) ligand showed the best results among the ligands, so the following experiments were conducted to find the optimum conditions of the reaction based on this ligand.

[Example 2] Effect of each solvent on the polymerization reaction rate and molecular weight distribution

In order to find the solvent which shows the best effect in this invention, superposition | polymerization was performed using various solvents. Proper amount of Cu ^I X (X = Cl, Br) and MMA (20.02 g, 0.20 mol) as the ligand and monomer obtained in Preparation Example 1 were placed in a 50 mL Schlenk flask and the solvent (w / w = 1 : 1) was added. Solvents used were 1,2-dimethoxybenzene (Veratrole), chlorobenzene (PhCl), phenylether (Ph ₂ O), toluene and polymerized under bulk without solvent and compared with each data. To avoid contact with air, this was done in a glove box. The flask was placed in an oil bath, mixed for 10 minutes at 60 ° C. under inert gas, and then an appropriate amount of initiator (ethyl 2-bromoisobutyrate; EB i B) was injected into the syringe. The molar ratio of each reactant is [CuBr] _o : [Ligand] _o : [EB i B] _o : [MMA] _o = 1: 2: 1: 400. The apparent rate constant ( k _obs ) was then determined by taking samples every 30 minutes and then measuring the amount of monomer that remained unpolymerized using an NMR analyzer. After 3 hours and 30 minutes, the reaction was terminated, and the polymer was precipitated in methanol solution and dried in a vacuum oven at a temperature of 60 ° C. Thereafter, the reactants were measured by molecular weight using a GPC analyzer to measure the number average molecular weight (M _n ) and molecular weight distribution (M _w / M _n ) of the polymerized MMA.

Solvent type % Conversion M _n M _w / M _n k _obs (10 ^-4 s ^-1 ) Veratrole 79 39,110 1.14 1.19 PhCl 62 33,370 1.16 0.82 Ph ₂ O 71 46,560 1.21 0.98 toluene 46 36,090 1.21 0.46 bulk 89 56,610 1.48 4.44

Example 3 Effect of Reaction Temperature on Polymerization Rate and Molecular Weight Distribution

In the present invention, polymerization was performed by varying the reaction temperature in order to find the optimum temperature condition. Proper amount of Cu ^I X (X = Cl, Br), ligand obtained in Preparation Example 1, MMA (20.02 g, 0.20 mol) as monomer and 1,2-dimethoxybenzene (w / w = 1: 1) as solvent Was placed in a 50 mL Schlenk flask. To avoid contact with air, this was done in a glove box. The flask was placed in an oil bath and mixed under an inert gas at a temperature of 26 ° C., 40 ° C., 60 ° C., 80 ° C., and 100 ° C. for 10 minutes, and then an appropriate amount of initiator (ethyl 2-bromoisobutyrate; EB i B) was injected into the flask. Injected into. The molar ratio of each reactant is [CuBr] _o : [Ligand] _o : [EB i B] _o : [MMA] _o = 1: 2: 1: 400. The apparent rate constant ( k _obs ) was then determined by taking samples every 30 minutes and then measuring the amount of monomer that remained unpolymerized using an NMR analyzer. After 3 hours and 30 minutes, the reaction was terminated, and the polymer was precipitated in methanol solution and dried in a vacuum oven at a temperature of 60 ° C. Thereafter, the reaction product was measured by molecular weight using a GPC analyzer to measure the number average molecular weight (M _n ) and molecular weight distribution (M _w / M _n ) of the polymerized MMA. Table 3 shows.

Polymerization temperature (℃) % Conversion M _n M _w / M _n k _obs (10 ^-4 s ^-1 ) 26 48 35,110 1.20 0.49 40 62 35,840 1.21 0.74 60 79 39,110 1.14 1.19 80 71 34,310 1.15 0.89 100 59 33,790 1.15 0.59

Example 4 Effect of Initiator Concentration on Polymerization Rate and Molecular Weight Distribution

In general, as the concentration of initiator is increased, the number of radicals in the reactor increases and the rate of polymerization increases. In the present invention, the experiment was performed while changing the ratio of the catalyst concentration and the initiator concentration in order to find the optimal initiator concentration. Proper amount of Cu ^I X (X = Cl, Br), ligand obtained in Preparation Example 1, MMA (20.02g, 0.20mol) as monomer and 1,2-dimethoxybenzene (w / w = 1: 1) as solvent Was placed in a 50 mL Schlenk flask. To avoid contact with air, this was done in a glove box. The flask was placed in an oil bath and mixed under an inert gas at a temperature of 60 ° C. for 10 minutes, and then an appropriate amount of initiator (ethyl 2-bromoisobutyrate; EB i B) was injected into the syringe. The molar ratio of each reactant is [CuBr] _o : [Ligand] _o : [EB i B] _o : [MMA] _o = 1: 2: 2: 400, 1: 2: 1: 400, 1: 2: 0.5: 400 to be. The apparent rate constant ( k _obs ) was then determined by taking samples every 30 minutes and then measuring the amount of monomer that remained unpolymerized using an NMR analyzer. After 3 hours and 30 minutes, the reaction was terminated, and the polymer was precipitated in methanol solution and dried in a vacuum oven at a temperature of 60 ° C. Thereafter, the reactants were measured by molecular weight using a GPC analyzer to measure the number average molecular weight (M _n ) and molecular weight distribution (M _w / M _n ) of the polymerized MMA.

Catalyst: Initiator % Conversion M _n M _w / M _n k _obs (10 ^-4 s ^-1 ) 1: 2 91 21,560 1.17 1.86 1: 1 79 39,110 1.14 1.19 1: 0.5 48 51,130 1.20 0.54

Example 5 Effect of Monomer Concentration on Polymerization Rate and Molecular Weight Distribution

In general, the smaller the concentration ratio of catalyst and monomer, the lower the molecular weight of the polymer and the higher the polymerization rate. However, when used industrially, the increase in the use of catalysts requires an increase in cost, a post-treatment step after the reaction, and results in poor yields. Therefore, it is necessary to find an optimal ratio of catalyst and monomer concentrations. Proper amount of Cu ^I X (X = Cl, Br), ligand obtained in Preparation Example 1, MMA (20.02 g, 0.20 mol) as monomer and 1,2-dimethoxybenzene (w / w = 1: 1) as solvent Was placed in a 50 mL Schlenk flask. To avoid contact with air, this was done in a glove box. The flask was placed in an oil bath and mixed under an inert gas at a temperature of 60 ° C. for 10 minutes, and then an appropriate amount of initiator (ethyl 2-bromoisobutyrate; EB i B) was injected into the syringe. The molar ratio of each reactant is [CuBr] _o : [Ligand] _o : [EB i B] _o : [MMA] _o = 1: 2: 1: 100, 1: 2: 1: 200, 1: 2: 1: 400 , 1: 2: 1: 800, 1: 2: 1: 1600. The apparent rate constant ( k _obs ) was then determined by taking samples every 30 minutes and then measuring the amount of monomer that remained unpolymerized using an NMR analyzer. After 3 hours and 30 minutes, the reaction was terminated, and the polymer was precipitated in methanol solution and dried in a vacuum oven at a temperature of 60 ° C. Subsequently, the reaction product was measured by molecular weight using a GPC analyzer to measure the number average molecular weight (M _n ) and molecular weight distribution (M _w / M _n ) of the polymerized MMA. .

Catalyst: Monomer % Conversion M _n M _w / M _n k _obs (10 ^-4 s ^-1 ) 1: 100 87 21,050 1.14 6.58 1: 200 80 27,340 1.14 3.19 1: 400 79 39,110 1.14 1.19 1: 800 33 43,840 1.41 0.35 1: 1600 Unreacted n

Example 6 Effect of Halogen on Polymerization Kinetics and Molecular Weight Distribution

The halogen atom used in ATRP uses Br more than Cl because the use of Br speeds up the polymerization. In addition, in the case of Br, since the initiation rate is faster than Cl, it is useful for polymer polymerization of relatively low molecular weight. In general, in ATRP, the stronger the electron affinity of the halogen element, the less the equilibrium reaction of the halogen atoms between the halide and the metal ligand occurs, so that the polymerization rate decreases and more side reactions occur. This experiment was carried out to see the effect of the halogen atoms in the present invention. Proper amount of Cu ^I X (X = Cl, Br), ligand obtained in Preparation Example 1, MMA (20.02 g, 0.20 mol) as monomer and 1,2-dimethoxybenzene (w / w = 1: 1) as solvent Was placed in a 50 mL Schlenk flask. To avoid contact with air, this was done in a glove box. The flask was placed in an oil bath and mixed under an inert gas at a temperature of 60 ° C. for 10 minutes, and an appropriate amount of initiator (ethyl 2-bromoisobutyrate; EB i B) was injected into the syringe. The molar ratio of each reactant is [CuX] _o (X = Br, Cl): [Ligand] _o : [EB i B] _o : [MMA] _o = 1: 2: 1: 400. Thereafter, samples were taken every 30 minutes and the apparent rate constant ( k _obs ) was determined by measuring the amount of monomer remaining unpolymerized using an NMR analyzer. After 3 hours and 30 minutes, the reaction was terminated, and the polymer was precipitated in methanol solution and dried in a vacuum oven at a temperature of 60 ° C. Thereafter, the reactant was measured by molecular weight using a GPC analyzer to measure the number average molecular weight (M _n ) and molecular weight distribution (M _w / M _n ) of the polymerized MMA.

halogen % Conversion M _n M _w / M _n k _obs (10 ^-4 s ^-1 ) Br 79 39,110 1.19 1.19 Cl 32 19,030 0.27 0.27

Example 7 Application to Other Monomers and Comparison with MMA

[Example 1] to [Example 6] Among the ligands listed above, the best reactivity was cyclopentyl pyridine-2-carboxyimidate (CpPCI) ligand, and the optimum condition for the reaction was 1,2-dimethoxy as a solvent. Benzene (Veratrole), reaction temperature 60 ℃, the initiator is ethyl 2-bromoisobutyrate (EB i B) and the molar ratio of each reactant is [CuBr] _o : [Ligand] _o : [EB i B] _o : [MMA] _o = 1: 2: 1: 400 and the polymerization was completed in 3-4 hours. However, in the case of styrene (ST) and methyl acrylate (MA), almost no reaction occurred under the same polymerization conditions. Comparison with MMA. First, in the case of MMA, the graph of ln {[M] _o / [M]} vs Time maintains linearity throughout the polymerization reaction and is shown in FIG. 2.

On the other hand, the result of polymerizing styrene by the catalyst shown in the present invention is shown in FIG. The polymerization was carried out in bulk, and the molar ratio of each reactant was [CuBr] _o : [Ligand] _o : [EB i B] _o : [ST] _o = 1: 2: 1: 200, temperature was 100 ° C and reaction time was The catalyst lasts for more than 100 hours, and the curves appear in the graph as a whole. Therefore, it is judged that the catalyst does not properly perform the function of ATRP during the polymerization of styrene.

In FIG. 4, the polymerization result of methyl acrylate by this catalyst is plotted. The reaction is linear but bulky and the molar ratio of each reactant is [CuBr] _o : [Ligand] _o : [EB i B] _o : [MA] _o = 1: 2: 1: 400, polymerization rate is MMA It was found to be very late compared to the polymerization. Based on the experimental results, the apparent velocity constant, number average molecular weight (M _n ) and molecular weight distribution (M _w / M _n ) are shown in Table 7.

Monomer type MMA ST MA Conversion rate 79 51 65 Reaction time 3.5 100 25 Polymerization condition Solution phase Bulk Award Bulk Award M _n 39,110 22,340 20,500 M _w / M _n 1.14 1.35 1.07 k _obs (10 ^-4 s ^-1 ) 1.19 0.02 0.12

As described above, according to the present invention, in the polymerization of vinyl monomer methyl methacrylate (methyl methacrylate, MMA) using ATRP, the reaction temperature of the existing system is too high (90 ° C. or more), or the reaction rate. To improve the disadvantage of the too slow and provide a new method of polymerization of methyl methacrylate using atomic transfer radical polymerization based on the carboxyimidate ligand that can minimize the molecular weight distribution and suppress side reactions between the radicals, which is an advantage of the existing ATRP There is an advantage to this.

In addition, there is an advantage in providing a technology that enables the synthesis of a relatively simple and low-cost ligand by improving the difficulty of synthesis in the polymerization of the existing ligand and the cost problem occurs in industrial applications.

Claims (5)

In polymerization of vinyl-based or diene monomers such as methyl methacrylate (MMA), styrene (ST), methacrylate (MA) by ATRP, (a) preparing a catalyst represented by Formula 1 below; And Formula 1 MA _a (L) _n (M is Cu, A is halogen atom) L is represented by the following Chemical Formula 2 as a ligand of Cu metal. Formula 2 R ¹ , R ² , R ³ , R ⁴ , and R ⁵ in Formula 2 may be the same as or different from each other, hydrogen, an alkyl group or an alkoxy group of C ₁ to C ₁₂ , an aryl group or an aryloxy group of C ₆ to C ₂₀ , Selected from C ₃ to C ₂₀ cycloalkyl group, R ⁶ is selected from hydrogen, C ₁ to C ₁₂ alkyl group, C ₆ to C ₂₀ aryl group, C ₃ to C ₂₀ cycloalkyl group as substituent of the ligand. (b) adding the ligand catalyst of step (a) to the monomer, stirring and adding the initiator to perform polymerization. The ATRP polymerization method according to claim 1, wherein the amount of the ligand added is twice the molar ratio of the transition metal. The ATRP polymerization method according to claim 1, wherein the temperature is in the range of 20 ° C to 100 ° C. According to claim 1, wherein the initiator is ATRP polymerization method, characterized in that the concentration is 0.5 to 2 times the molar ratio of the transition metal catalyst. The ATRP polymerization method according to claim 1, wherein the monomer has a concentration of 100 to 800 times the molar ratio of the transition metal catalyst.