JPH0564138B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention relates to electron-withdrawing monomers, electron-withdrawing polymers, and methods for producing them. More specifically, 2,4-dicyanostyrene, poly(2,4-
The present invention relates to copolymers having dicyanostyrene) and 2,4-dicyanostyrene units, and methods for producing them. The electron-withdrawing polymer reacts with an electron donor to form a polymeric charge transfer complex. Such polymeric charge transfer complexes can be used for electrophotography,
It is extremely useful as an optoelectronic material for xerography. Furthermore, these polymeric charge transfer complexes are viewed as promising as electrically conductive materials. Additionally, electron-withdrawing polymers are useful as carriers for affinity chromatography. [Prior art] As electron-withdrawing polymers, 2,4,5,7-
Polymer of spiro compound having tetranitrofluorene skeleton, polymer of 2,4,7-trinitro-9-fluorenyl methacrylate and 2'-ethylmethacrylate-4,5,7-trinitro-9-fluorenone-2- Carboxylate polymers and the like are known. However, since the monomers of these polymers are difficult to purify, it is difficult to produce pure electron-withdrawing polymers. Furthermore, since these monomers have a nitro group, chain transfer to the nitro group is large during radical polymerization, so they have the disadvantage that a polymer with a high molecular weight cannot be obtained. [Problems to be Solved by the Invention] The purpose of the present invention is to provide a new electron-withdrawing polymer that can replace the electron-withdrawing polymer for which it has been difficult to obtain high-purity products and a method for producing the same. be. [Means for solving the problem] The present invention solves the problem by Using 2,4-dicyanostyrene represented by and p-ethylbenzonitrile as starting materials, a step of substituting one hydrogen at the meta position with respect to the nitrile group with bromine, a step of substituting this bromine group with a cyano group, and A method for producing 2,4-dicyanostyrene, which comprises a step of substituting one hydrogen of an ethyl branch with bromine and a step of converting this bromoethyl group into a vinyl group by dehydrobromination, and
general formula (In the formula, n is an integer of 30 to 30,000) and the 2,4-dicyanostyrene is used as a monomer in the absence of a catalyst or in the presence of a radical initiator. To,
The above-mentioned poly(2,4
-dicyanostyrene), and 5 to 80 mol% of the 2,4-dicyanostyrene and the general formula () (In the formula, R ¹ represents a C ₁ to C ₄ lower alkyl group,
Ar is a general formula

Indicates a group represented by [Formula], where X is H, C ₁ to C ₄ lower alkoxy group, C ₁ to
(represents a dialkylamino group having a _C4 lower alkyl group or a _C1 to _C4 lower alkylthio group)
Compound () or general formula () represented by (In the formula, R ² is a C ₁ to C ₄ lower alkyl group, R ³ is
_C1 to _C4 lower alkyl group, aralkyl group or general formula

[Effect]

The electron-withdrawing polymer of the present invention is poly(2,4
-dicyanostyrene) and 2,4-dicyanostyrene units, respectively.
- Can be easily produced by radical polymerization of dicyanostyrene alone or together with other monomers. 2,4-dicyanostyrene, which has an electron-withdrawing functional group that is not affected by the polymerization reaction, can be prepared by, for example, p-ethylbenzonitrile (shown by the following formula, abbreviated as (), (same below) as the starting material,
It can be synthesized through the following steps: nuclear bromine substitution, substitution of a bromine group with a cyano group, bromine substitution of an ethyl branch, and conversion of a bromoethyl group into a vinyl group by dehydrobromination.

[Table] Nitrile

That is, first, 3-bromo-4-ethylbenzonitrile () is prepared by adding p-ethylbenzonitrile () dropwise to p-ethylbenzonitrile () in the presence of a Lewis acid such as iron chloride or aluminum chloride, and then adding bromine dropwise to the reaction temperature.
It can be synthesized by processing at 50-60°C for 2-3 hours. 4-ethyl isophthalonitrile () can be synthesized from 3-bromo-4-ethylbenzonitrile () by the so-called Rosenmund-von Broun reaction. That is, by heating and refluxing 3-bromo-4-ethylbenzonitrile () in an aprotic polar solvent such as dimethyl formamide (DMF) in the presence of cuprous cyanide, 4-ethyl isophthalonitrile is obtained. ()
can be synthesized. 4-(1-bromoethyl)isophthalonitrile () is obtained by converting 4-ethyl isophthalonitrile () to bromine, a brominating agent such as N-bromosuccinimide, sulfuryl bromide, azobisisobutyronitrile,
It is obtained by heating under reflux in a solvent such as carbon tetrachloride or benzene in the presence of an initiator such as benzoyl peroxide. 2,4-dicyanostyrene () is 4-(1
-bromoethyl)isophthalonitrile () in acetonitrile in the presence of a small amount of polymerization inhibitor with an organic base such as triethylamine. The polymerization inhibitors used here include picric acid, 4-t-butylcatechol, hydroquinone, 2,2,6,6-tetramethyl-
Examples include 4-hydroxy-piperidine-1-oxide. Preferably 2, 2, 6,
6-tetramethyl-4-hydroxy-piperidine-1-oxide. The amount of polymerization inhibitor added is 0.5 mol% relative to 4-(1-bromoethyl)isophthalonitrile ().
The above is sufficient. If no polymerization inhibitor is added, the produced 2,4-dicyanostyrene () will polymerize, which is not preferable. 2,4-Dicyanostyrene () is a colorless needle crystal (melting point 154-156°C) that can be easily recrystallized from ethanol. In its ultraviolet absorption spectrum, λmax
Absorption at =267nm (ε=15500) was observed. 1st
The figure shows an infrared absorption spectrum of 2,4-dicyanostyrene (2). According to Figure 1, the absorption at 2220 cm ^-1 attributed to nitrile, the absorption at 1595 cm ^-1 attributed to the double bond conjugated to the aromatic ring, the absorption at 970 and 930 cm ^-1 attributed to the vinyl group, etc. Is recognized. Furthermore, the proton nuclear magnetic resonance spectrum of 2,4-dicyanostyrene shown in Figure 2 (solvent
CDCl ₃ , internal standard; TMS), the proton absorption of the vinyl group is δ5.79 (q, 1H, J = 11, 1Hz),
6.14 (q, 1H, J = 17, 1Hz) and 7.14 (q,
1H, J = 11, 17Hz), and the absorption of aromatic nucleus protons is δ7.75-7.85 (m, 2H), 7.93 (m, 1H)
recognized. 2,4-dicyanostyrene and N-
Vinyl carbazole or m-N,N-dimethylaminophenyl methacrylate was mixed in tetrahydroquinone, and the ultraviolet absorption spectrum was measured. As a result, 2,4-dicyanostyrene and N-
For vinyl carbazole type, 370 to 410 nm, 2,
In the 4-dicyanostyrene and m-N,N-diaminophenyl methacrylate system, absorption attributable to the charge transfer complex was observed at 370 to 430 nm. The method for producing poly(2,4-dicyanostyrene) of the present invention is to simply heat 2,4-dicyanostyrene () obtained by the above method in a solvent such as benzene, hexane, or acetonitrile without a catalyst. Polymerization can be carried out simply by heating, or it can be more easily polymerized by heating in the presence of a radical initiator such as azobisisobutyronitrile or benzoyl peroxide. In the solvent, the concentration of 2,4-dicyanostyrene monomer is 0.1 to 100 wt%, preferably 1 to 100 wt%.
used as. Further, the concentration of the radical initiator is preferably in the range of 0.01 to 10 mol% based on the number of moles of the monomer. The polymerization temperature varies depending on the presence or absence of a radical initiator or the type of radical initiator used, but it is usually preferably carried out in the range of 20°C to 150°C. It is preferable that the polymerization time is usually in the range of 2 hours to 200 hours. The molecular weight of the resulting polymer can be adjusted within a wide range of 3,000 to 3,000,000 by selecting the monomer concentration, radical initiator concentration, and polymerization temperature. In order to obtain particularly high molecular weight polymers, it is necessary to increase the monomer concentration, to decrease the radical initiator concentration, or to decrease the polymerization temperature. FIG. 3 shows the infrared absorption spectrum of the poly(2,4-dicyanostyrene) of the present invention obtained by homopolymerizing 2,4-dicyanostyrene () as described above. 970 cm ^- based on the out-of-plane bending vibration of the vinyl group observed in the 2,4-dicyanostyrene monomer in Figure 1.
It can be seen that the absorptions at ¹ and 930 cm ^-1 have disappeared in Figure 3. However, based on nitrile
Absorption of 2220 cm ^-1 is maintained. This homopolymer was soluble in acetonitrile, acetone, DMF, etc., and insoluble in chloroform, benzene, ethyl acetate, methanol, etc. 2,4-dicyanostyrene () can be copolymerized with various monomers. For such monomers, the general formula (In the formula, R ¹ represents a C ₁ to C ₄ lower alkyl group,
Ar is a general formula

Indicates a group represented by [Formula], where X is H, C ₁ to C ₄ lower alkoxy group, C ₁ to
(represents a dialkylamino group having a _C4 lower alkyl group or a _C1 to _C4 lower alkylthio group)
Compound () or general formula represented by (In the formula, R ² is a C ₁ to C ₄ lower alkyl group, R ³ is
C ₁ - C ₄ lower alkyl group, aralkyl group or general formula

〔Effect of the invention〕

According to the present invention, it is possible to easily provide the novel electron-withdrawing monomer 2,4-dicyanostyrene (2,4-dicyanostyrene) as a highly purified product together with its manufacturing method. In addition, by using this new monomer (), new electron-withdrawing homopolymers poly(2,4-dicyanostyrene) and copolymers having 2,4-dicyanostyrene units and their production can be produced. law can be provided. These polymers retain the electron-withdrawing functional group of the monomer (), so they have the property of forming a polymeric charge transfer complex when combined with an electron-donating substance. It is expected to be used for applications such as optoelectronic materials and conductive materials. [Example] Hereinafter, the present invention will be explained in more detail with reference to Examples. Example 1 Synthesis of 3-bromo-4-ethylbenzonitrile () 46.6 g of anhydrous aluminum chloride was charged into a 100 ml three-necked flask equipped with a mechanical stirrer, a dropping funnel, and a Dimroth equipped with a hydrogen bromide absorption tube.
While stirring, 14.1 g of p-ethylbenzonitrile () was added dropwise. The reaction mixture exothermed violently and solidified. After the dropwise addition was completed, the reaction vessel was shielded from light, and 19.8 ml of bromine was added dropwise. Then 2 at 50-60℃
heated for an hour. After cooling, the reaction solution was poured into ice water acidified with hydrochloric acid, and the solution was extracted with toluene. The extract was washed twice each in the order of water, 5% aqueous sodium carbonate solution, and water. After drying the extract over anhydrous sodium sulfate, the solvent was distilled off under reduced pressure. The residue was distilled under reduced pressure to obtain 19.6 g of a colorless liquid as a fraction with a boiling point of 83-86°C/1.5 mmHg. The product solidified after distillation and cooling, becoming a colorless solid with a melting point of 43.5-45.0°C. The yield was 86.3 mol%. The product was identified by elemental analysis, infrared absorption spectrum, and proton nuclear magnetic resonance spectrum. 3-Bromo-4-ethylbenzonitrile () bp.83~86℃/1.5mmHg mp.43.5~45.0℃ Infrared absorption spectrum (NaCl) 2220, 880, 835cm ^-1 Proton nuclear magnetic resonance spectrum (solvent:
CCl ₄ , internal standard TMS) δ1.23 (t, 3H, J = 7.5Hz), 2.77 (q, 2H, J = 7.5Hz), 7.2 - 7.7 (m, 3H) Elemental analysis H CN (wt%) Actual value 3.67 51.07 6.45 Calculated value 3.84 51.46 6.67 (C ₉ H ₈ NBr) Example 2 4-ethyl isophthalonitrile ()
Synthesis of 16.9 g of 3-bromo-4-ethylbenzonitrile (), 8.3 g of cuprous cyanide, and dimethylformamide in a 100 ml three-necked flask equipped with a Dimroth.
I added 14ml. After heating under reflux for 5 hours, the reaction mixture was poured while hot into 75 ml of a 4N aqueous hydrochloric acid solution in which 33 g of ferric chloride hexahydrate was dissolved. This reaction solution was further heated at 70-80°C for 20 minutes.
This reaction solution was extracted with toluene, and the extract was washed in the order of dilute hydrochloric acid, water, 10% aqueous sodium hydroxide solution, and water. After drying this extract over anhydrous sodium sulfate, the solvent was distilled off under reduced pressure. The residue was recrystallized with n-hexane to obtain 9.7 g of white needle crystals with a melting point of 72.5-73.5°C. The yield was 78 mol%. The product was identified by elemental analysis, infrared absorption spectrum, and proton nuclear magnetic resonance spectrum. 4-ethyl isophthalonitrile () mp.72.5-73.5℃ Infrared absorption spectrum (KBr) 2225, 890, 840 cm ^-1 Proton nuclear magnetic resonance spectrum (solvent CCl ₄ ,
Internal standard TMS) δ1.37 (t, 3H, J = 7.5Hz), 2.95 (q, 2H, J = 7.5Hz), 7.3-7.9 (m, 3H) Elemental analysis HCN (wt%) Actual value 5.02 76.51 17.96 Calculated value (C ₁₀ H ₈ N) 5.16 76.90 17.94 Example 3 Synthesis of 4-(1-bromoethyl)isophthalonitrile () In a 200 ml round bottom flask, 10.5 g of 4-ethyl isophthalonitrile (), N- 12.7 g of bromosuccinimide, 50 mg of azobisisobutyronitrile, and 80 ml of carbon tetrachloride were charged, and the mixture was heated under reflux for 24 hours under a nitrogen stream. After the reaction was completed, suspended solids were removed by thermal aging. The liquid was distilled under reduced pressure to remove the solvent. The residue was recrystallized from isopropanol to obtain 12.5 g of pale orange crystals with a melting point of 90-90.5°C. The yield was 79.1 mol%. The product was identified by elemental analysis, infrared absorption spectrum, and proton nuclear magnetic resonance spectrum. 4-(1-bromoethyl)isophthalonitrile
() mp.90~90.5℃ Infrared absorption spectrum (KBr) 2220, 900, 860 cm ^-1 Proton nuclear magnetic resonance spectrum (solvent: CCl ₄ ,
Internal standard: TMS) δ2.09 (d, 3H, J=7Hz), 5.48 (q, 1H, J=7Hz), 7.85-8.2 (m, 3H) Elemental analysis HCN (wt%) Actual value 3.08 51.43 12.05 Calculated value 3.00 51.09 11.92 (C ₁₀ H ₇ N ₂ Br) Example 4 Synthesis of 2,4-dicyanostyrene () In a 50 ml round bottom flask, add 4-(1-bromoethyl)
Isophthalonitrile () 5.00g, triethylamine 7.0g, 2,2,6,6-tetramethyl-4
20 mg of -hydroxypiperidine-1-oxide and 20 ml of acetonitrile were added, and the mixture was heated under reflux for 9 hours. After the reaction was completed, the solvent was distilled off under reduced pressure, the residue was dissolved in chloroform, and insoluble materials were separated. The liquid was washed with water, a 15% aqueous solution of caustic soda, and water in this order.
After drying this organic phase with anhydrous sodium sulfate,
The solvent was distilled off, and the residue was subjected to silica chromatography (developing solvent: chloroform). After chloroform was distilled off, the precipitated solid was recrystallized from ethanol to obtain 2.14 g of colorless needle crystals with a melting point of 154-156°C. The yield was 65.2 mol%. The product was identified by elemental analysis, infrared absorption spectrum, proton nuclear magnetic resonance spectrum, etc. 2,4-Dicyanostyrene () mp.154-156℃ Ultraviolet absorption spectrum (solvent: acetonitrile) λmax=267nm (ε=15500) Infrared absorption spectrum (KBr) 2220, 1595, 970, 930cm ^-1 Proton nuclear magnetic resonance Spectrum (solvent:
CDCl ₃ , internal standard: TMS) δ5.79 (q, 1H, J = 11, 1Hz), 6.14 (q, 1H, J = 11, 1Hz), 7.14 (q, 1H, J = 11, 17Hz), 7.75 ~7.85 (m, 2H), 7.93 (m, 1H) Elemental analysis C H N (wt%) Actual value 78.27 3.77 18.26 Calculated value (C ₁₀ H ₆ N ₂ ) 77.91 3.92 18.17 Example 5-27 2 in glass ampoule , 4-dicyanostyrene,
Add the monomers, initiator and solvent shown in Table 1,
This was repeatedly degassed three times using the freeze-throw method, and the tube was sealed. This ampoule was placed in a constant temperature bath kept at 60°C. After carrying out the reaction for the polymerization time shown in Table 1, the ampoule was opened and the contents were poured into methanol containing a small amount of calcium nitrate to obtain a polymer as a precipitate. The homopolymer of 2,4-dicyanostyrene and the copolymer of 2,4-dicyanostyrene and methyl methacrylate were purified by reprecipitation from acetonitrile, and the copolymer of 2,4-dicyanostyrene and styrene was purified from acetone. I went. The results are shown in Tables 1 and 2. The copolymer composition of 2,4-dicyanostyrene was calculated from elemental analysis. Figure 3 shows the infrared absorption spectrum of 2,4-dicyanostyrene homopolymer, and the infrared absorption spectra of copolymers of 2,4-dicyanostyrene and styrene and 2,4-dicyanostyrene and methyl methacrylate. Shown in FIGS. 4 and 5. 3rd to 5th
In both of the figures, a large absorption at 2220 cm ^-1 due to nitrile is observed. Furthermore, Table 3 shows the polystyrene equivalent number average molecular weight of the polymer determined from gel chromatography.

【table】

[Table] Methyl lylate
AIBN; Azobisisobutyronitrile

【table】

【table】

【table】 [Brief explanation of the drawing]

FIG. 1 and FIG. 2 respectively show 2 and 2 of the present invention.
These are an infrared absorption spectrum and a proton nuclear magnetic resonance spectrum of 4-dicyanostyrene ().
Figures 3, 4, and 5 show poly(2,4-dicyanostyrene), a copolymer of 2,4-dicyanostyrene () and styrene, and 2,4-dicyanostyrene () of the present invention, respectively. This is an infrared absorption spectrum of a copolymer of and methyl methacrylate.

Claims (1)

[Claims] 1 formula 2,4-dicyanostyrene represented by 2 After brominating p-ethylbenzonitrile to form 3-bromo-4-ethylbenzonitrile, the bromine was replaced with a cyano group, and one hydrogen of the ethyl branch was further replaced with bromine, resulting in 4-(1-bromoethyl )
A method for producing 2,4-dicyanostyrene, which comprises treating isobutalonitrile with an organic base in acetonitrile in the presence of a polymerization inhibitor.