JP4986117B2 - Phosphonium salt supported on magnetic fine particles, production method thereof, magnetic fine particle supported phase transfer catalyst comprising the phosphonium salt, and phase transfer reaction using the same - Google Patents

Description

  The present invention relates to a novel phosphonium salt that is easy to separate and recover and can be reused, a method for producing the same, a phase transfer catalyst comprising the above-mentioned magnetic fine particle-supported phosphonium salt, and a phase transfer reaction using the same.

  The phase transfer reaction is widely recognized as an environmentally harmonious organic synthesis reaction, and has been applied to industrial processes for many compounds. However, the phosphonium salt used as a catalyst for the phase transfer reaction has a problem that it cannot be reused because it is difficult to separate and recover after the reaction.

  As a means for solving the above-described problem, a method has been proposed in which a phosphonium salt is supported on a solid such as a polymer so that the catalyst can be separated and recovered by filtration. For example, Non-Patent Document 1 describes a phase transfer reaction using a phosphonium salt supported on polystyrene. However, by supporting the polymer, new problems such as limited solvents that can be used for swelling with organic solvents, poor operability, physical fragility, poor thermal stability, etc. A point is born.

On the other hand, magnetic materials such as magnetite and ferrite can produce nano-sized fine particles, and functional organic molecules can be supported on the surface thereof. For example, Patent Documents 1 and 2 describe methods for producing physiologically active substances and enzymes supported on nano-sized magnetic fine particles. Moreover, since these magnetic fine particles are inorganic materials, they are not swelled by an organic solvent, and are expected to be thermally and physically stable as compared with polymer particles. Furthermore, it has the greatest characteristic that the polymer can quickly separate and recover by magnetism.
However, in the above-mentioned patent documents, what is supported on the magnetic fine particles is only a physiologically active substance or an enzyme, and the present situation is not yet known about an example in which a phosphonium salt is supported as a phase transfer catalyst.
US Pat. No. 4,672,040 JP 2005-60221 A Macromolecules, 1984, 17: 1812-1814

  The present invention has been made to overcome the above-mentioned problems of the prior art, and an object thereof is to provide a phase transfer catalyst that can be separated and recovered by magnetism and can be reused. It is.

  As a result of intensive studies to solve the above problems, the present inventors have made it possible to operate the catalyst magnetically by immobilizing the phase transfer catalyst on the magnetic fine particles, so that the catalyst can be separated and recovered after the reaction. And it has been found that reuse is greatly simplified, and the present invention has been completed.

That is, according to the present invention, the following inventions are provided.
(1) On the magnetic fine particles, the following general formula (1)

(In the formula, R ¹ represents a hydrocarbon group. R ² , R ³ , and R ⁴ each represents a hydrocarbon group, which may be bonded to each other to form a ring. X ⁻ represents an anion of an acid. And a siloxy group having a phosphonium salt moiety represented by formula (1).
(2) The following general formula (2)

(In the formula, R ¹ .R ^2, R ^3, R ⁴ representing a hydrocarbon group is a hydrocarbon group, good .R ⁵ also form a ring, each from 1 carbon atoms represents the 3 alkyl groups .X ^- magnetic fine particle-supporting phosphonium above (1) which comprises reacting the phosphonium salt and the magnetic fine particles having a trialkoxysilyl group represented by represents) an anion of an acid. Method for producing salt.
(3) A phase transfer catalyst comprising the phosphonium salt carrying a magnetic fine particle as described in (1) above.
(4) In the phase transfer reaction, a method which comprises using a magnetic particulate support phosphonium salt of the above (1) to the catalyst.

Effects of the present invention

  According to the present invention, a magnetic fine particle-supporting phosphonium salt that can be magnetically operated can be obtained. By using the magnetic particle-supported phosphonium salt thus obtained as a phase transfer catalyst, not only can the phase transfer reaction proceed effectively, but also the catalyst can be quickly and easily separated and recovered and reused.

  The novel magnetic fine particle-supported phosphonium salt obtained by the present invention is obtained by binding a siloxy group having a phosphonium salt moiety represented by the general formula (1) on a magnetic fine particle. expressed.

(In the formula, M represents a magnetic fine particle and represents a magnetic fine particle R ¹ hydrocarbon group. R ² , R ³ , and R ⁴ represent a hydrocarbon group, and each may be bonded to form a ring. X ^- represents an anion of acid).
Hereinafter, the details of the phosphonium salt carrying magnetic fine particles represented by the above [Chemical Formula 5] will be specifically described.
M represents magnetic fine particles. The type of magnetic fine particles used as a carrier in the present invention is not particularly limited, and any known magnetic particles such as magnetite, ferrite, maghemite, etc. can be used.
The magnetic fine particles of any size can be used in the present invention, but if they are too small, it is difficult to recover them by magnetism, and if they are too large, the catalyst efficiency decreases, so those having a particle diameter of 100 nm to 100 μm. preferable.

R ¹ is a hydrocarbon group, and is selected from an alkylene group and an aryl group with or without a substituent on the aromatic ring. Specific examples include a methylene group, an ethylene group, a propylene group, a butylene group, a phenyl group, a naphthyl group, a biphenyl group, and a binaphthyl group.
R ² , R ³ and R ⁴ are hydrocarbon groups which may be bonded to each other to form a ring, and have a substituent on the alkyl group, alkylene group, aralkyl group or aromatic ring; Is selected from aryl groups that do not have. Specifically, methyl group, ethyl group, propyl group, butyl group, pentyl group, hexyl group, heptyl group, octyl group, isopropyl group, isobutyl group, cyclopentyl group, cyclohexyl group, methylene group, ethylene group, propylene group, Examples include butylene group, benzyl group, phenethyl group, phenyl group, naphthyl group, biphenyl group, binaphthyl group, 4-methoxyphenyl group and the like.
Further, X ⁻ represents an anion of an acid. Preferable examples include, specifically, F ⁻ , Cl ⁻ , Br ⁻ and I ⁻ halogen ions, OH ⁻ , HSO ₄ ⁻ , NO ₃ ⁻ , (CF ₃ SO ₂ ) ₂ N ⁻ and CF ₃ SO _{3. ^{-, (CF 3 SO 2)}} 3 C -, PF 6 -, BF 4 - and others as mentioned, is not limited thereto.

Next, the method for producing the magnetic fine particle-supported phosphonium salt of the present invention will be described below .
The magnetic fine particle-supported phosphonium salt of the present invention has the following general formula (2):

(In the formula, R ¹ represents a hydrocarbon group. R ² , R ³ , and R ⁴ each represents a hydrocarbon group, which may be bonded to each other to form a ring. R ⁵ has 1 carbon number. represents the 3 alkyl groups .X ^- it can be obtained by reacting the phosphonium salt and the magnetic fine particles having a trialkoxysilyl group represented by represents) an anion of an acid in a solvent..

  The solvent that can be used for this reaction is not particularly limited as long as it can dissolve the phosphonium salt represented by the general formula (2) as a raw material. Specifically, ethanol, methanol, 1-propanol, 2-propanol, Examples include chloroform, dichloromethane, dichloroethane and the like. These solvents are not limited to being used alone, and may be used by appropriately mixing them. In this reaction, the reaction may be promoted by adding 0.5 to 1% of water with respect to the organic solvent.

  The reaction conditions are preferably in the range of 0 ° C. to 150 ° C., more preferably 25, because the reaction is difficult to proceed if the reaction temperature is too low, and undesirable side reactions may occur if the reaction temperature is too high. It is in the range of ℃ to 120 ℃. The reaction time cannot be generally determined, but usually 12 hours to 24 hours is sufficient.

  In the present invention, there is no particular limitation on the use ratio of the phosphonium salt represented by the general formula (2) as a raw material and the magnetic fine particles, but if the proportion of the phosphonium salt as a raw material is too small relative to the magnetic fine particles, It is preferable to use a phosphonium salt in the range of 0.5 to 5 moles per mole of magnetic fine particles because the production cost may be wasted even if the amount is excessively used.

  By using the phosphonium salt carrying the magnetic fine particles of the present invention as a phase transfer catalyst, various phase transfer reactions can proceed. Specific examples include halogen exchange reaction, dehydrohalogenation reaction, ether synthesis reaction, cyanation reaction, oxidation reaction and the like. The reaction examples among these are shown below. The magnetic fine particle-supported phosphonium salt of the present invention can be used for the phase transfer reaction described above, and if it is a phase transfer reaction, it can also be used for a phase transfer reaction other than the phase transfer reactions listed here. Can do.

The following reaction can be performed by using the magnetic particle-supported phosphonium salt of the present invention represented by the above [Chemical Formula 5] as a catalyst.
That is, in the presence of the catalyst, the following general formula (3)
R ⁶ -X ² (3)
(Wherein R ⁶ represents a hydrocarbon group, and may be any group selected from an alkyl group having 1 to 20 carbon atoms and a benzyl group. X ² represents a halogen atom selected from F, Cl, Br, and I. And an alkyl halide represented by the following general formula (4)
R ⁷ OM ² (4)
(Wherein R ⁷ represents a hydrocarbon group, and may be any group selected from an alkyl group having 1 to 20 carbon atoms, a phenyl group, and a naphthyl group. M ² is a metal atom selected from Li, Na, and K. In the presence of a solvent, a metal alkoxide represented by the following general formula (5)
R ⁶ OR ⁷ (5)
(Wherein R ⁶ and R ⁷ have the same meaning as described above) can be produced.

  In this reaction, a raw material and a catalyst are added and dissolved in a solvent. As the solvent, water and an organic solvent are used. As the organic solvent, hydrocarbon, halogenated hydrocarbon or the like is used. The reaction temperature is not limited, but if it is too low, the progress of the reaction is slow, and if it is too high, an undesirable side reaction may occur. During the reaction, the reaction solution is vigorously stirred. After the reaction is complete, the magnet is brought into close contact with the outer wall of the reaction vessel, so that only the catalyst accumulates on the inner wall of the reaction vessel, so that only the reaction solution containing the product can be separated by decantation. The yield of the target substance can be determined by analyzing the reaction solution by gas chromatography, but it is also possible to isolate the target substance by solvent extraction. Further, since the catalyst remains in the reaction vessel, it can be used as it is for the next reaction.

  Thus, the phase transfer reaction can be efficiently performed by using the phosphonium salt carrying the magnetic fine particles of the present invention represented by the above [Chemical Formula 5] as the phase transfer catalyst. Furthermore, by utilizing magnetism, it is possible to greatly simplify the separation and recovery and reuse of the catalyst as compared with the conventional polymer-supported phase transfer catalyst.

For further detailed description, examples will be described below, but the present invention is not limited to these examples.
(Example 1) (Production of magnetite fine particles)
1.99 g of iron (II) chloride tetrahydrate and 3.24 g of iron (III) chloride hexahydrate were added to 2.4 l of distilled water, degassed under reduced pressure, and stirred under a nitrogen atmosphere. After stirring until a homogeneous solution was obtained, 1.5N aqueous ammonium hydroxide solution was added dropwise with vigorous stirring until the pH of the solution reached about 9. The produced black colloid was aggregated with a neodymium magnet, and the supernatant was removed by decantation. The remaining black precipitate was washed 5 times with distilled water and twice with ethanol, and then dried under reduced pressure to obtain 1.63 g of magnetite.

Example 2 (Production of tri-n-butyl iodide [3- (trimethoxysilyl) propyl] phosphonium iodide)
Under a nitrogen atmosphere, 2.90 g (10.0 mmol) of (3-iodopropyl) trimethoxysilane was dissolved in 10 ml of dry toluene, and freeze deaeration was performed three times. To this solution, 2.02 g (10.0 mmol) of tri-n-butylphosphine was added and stirred at 100 ° C. for 36 hours. The crude phosphonium salt obtained by concentrating the reaction solution under reduced pressure was washed with hexane and hexane / ether (v / v = 1/1) three times, and then dried under reduced pressure to give 4.57 g (yield 93%) of colorless. A clear liquid was obtained. ^{From 1} H-NMR, ¹³ C-NMR, ³¹ P-NMR, FAB-MS, and elemental analysis, the target structure was confirmed.
¹ H-NMR (499 MHz, CDCl ₃ ): δ = 0.89 (t, 2H, 7.6 Hz), 0.99 (t, 9H, 7.0 Hz), 1.49-1.77 (m, 14H) ), 2.35-2.55 (m, 8H), 3.58 (s, 9H). ¹³ C-NMR (125 MHz, CDCl ₃ ): δ = 9.9 (d, J _p− = 15.5 Hz), 13.0, 15.5 (d, J _p− = 4.1 Hz), 18.9 (D, J _p− = 47.5 Hz), 21.2 (d, J _p− = 45.4 Hz), 23.4 (d, J _p− = 4.1 Hz), 23.3 (d, J _{p −} = 14.5 Hz), 50.3. ³¹ P-NMR (202 MHz, CDCl ₃ ): δ = 32.2. FAB-MS (positive): m / z = 365 ([M-I]). Elemental analysis: calculated value: C, 43.90; H, 8.60, measured value: C, 43.89; H, 8.55.

(Example 3) (Synthesis of tri-n-octyl iodide [3- (trimethoxysilyl) propyl] phosphonium iodide)
Under a nitrogen atmosphere, 5.36 g (18.5 mmol) of (3-iodopropyl) trimethoxysilane was dissolved in 10 ml of dry toluene, and freeze deaeration was performed three times. To this solution, 7.61 g of tri-n-octylphosphine (manufactured by Aldrich, purity 90%, corresponding to 18.5 mmol) was added and stirred at 120 ° C. for 36 hours. The crude phosphonium salt obtained by concentrating the reaction solution under reduced pressure was washed five times with hexane and then dried under reduced pressure to obtain 11.6 g (yield 95%) of a colorless transparent liquid. ^{From 1} H-NMR, ¹³ C-NMR, ³¹ P-NMR, FAB-MS, and elemental analysis, the target structure was confirmed.
¹ H-NMR (499 MHz, CDCl ₃ ): δ = 0.80-0.89 (m, 11H), 1.18-1.36 (m, 24H), 1.42-1.74 (m, 14H) ), 2.32-2.51 (m, 8H), 3.55 (s, 9H). ¹³ C-NMR (125 MHz, CDCl ₃ ): δ = 10.3 (d, J _p− = 14.5 Hz), 13.9, 15.9 (d, J _p− = 4.1 Hz), 19.5 (D, J _p− = 49.6 Hz), 21.6 (d, J _p− = 46.5 Hz), 21.8 (d, J _p− = 4.1 Hz), 22.4, 28.80, 28.83, 30.6 (d, J _p− = 14.5 Hz), 31.6, 50.6. ³¹ P-NMR (202 MHz, CDCl ₃ ): δ = 32.0. FAB-MS (positive): m / z = 533 ([M-I]). Elemental analysis: calculated value: C, 54.53; H, 10.07. Measurement: C, 54.57; H, 10.14.

(Example 4) (Synthesis of triphenyl [3- (trimethoxysilyl) propyl] phosphonium iodide)
In a nitrogen atmosphere, 2.90 g (10.0 mmol) of (3-iodopropyl) trimethoxysilane and 2.62 g (10.0 mmol) of triphenylphosphine were dissolved in 10 ml of degassed dry toluene, and then dissolved at 80 ° C. for 24 hours. Stir for hours. After cooling the reaction solution to room temperature, the crude phosphonium salt separated in the lower layer was dissolved in 5 ml of dry dichloromethane and reprecipitated by adding hexane. The precipitate was washed with toluene, further washed with ether three times, and dried under reduced pressure to obtain 4.43 g (yield 80%) of a white solid. ^{From 1} H-NMR, ¹³ C-NMR, ³¹ P-NMR, FAB-MS, and elemental analysis, the target structure was confirmed.
¹ H-NMR (499 MHz, CDCl ₃ ): δ = 1.10 (t, 2H, J = 7.6 Hz), 1.74-1.86 (m, 2H), 3.53 (s, 9H), 3.63-3.74 (m, 2H), 7.68-7.87 (m, 15H). ¹³ C-NMR (125 MHz, CDCl ₃ ): δ = 10.1 (d, J _p− = 16.6 Hz), 16.7 (d, J _p− = 3.1 Hz), 24.9 (d, J _p- = 48.5 Hz), 50.8, 118.1 (d, J _p- = 85.8 Hz), 130.6 (d, J _p- = 12.4 Hz), 133.7 (d, J _{p −} = 9.3 Hz), 135.2 (d, J _p− = 2.0 Hz). ³¹ P-NMR (202 MHz, CDC1 ₃ ): δ = 23.3. FAB-MS (positive): m / z = 425 ([M-I]). Elemental analysis: calculated value: C, 52.18; H, 5.47. Measurement: C, 52.24; H, 5.37.

Example 5 Synthesis of tri (4-methoxyphenyl) [3- (trimethoxysilyl) propyl] phosphonium iodide
After dissolving 2.90 g (10.0 mmol) of (3-iodopropyl) trimethoxysilane and 3.51 g (10.0 mmol) of tri (4-methoxyphenyl) phosphine in 30 ml of deaerated dry toluene under a nitrogen atmosphere. , And stirred at 80 ° C. for 24 hours. After cooling the reaction solution to room temperature, the crude phosphonium salt separated in the lower layer was washed with toluene three times, further washed with hexane three times, and dried under reduced pressure to give 6.38 g (yield 100%) of an amorphous white solid. Obtained. ^{From 1} H-NMR, ¹³ C-NMR, ³¹ P-NMR, FAB-MS, and elemental analysis, the target structure was confirmed.
¹ H-NMR (499 MHz, CDCl ₃ ): δ = 1.04 (t, 2H, J = 7.6 Hz), 1.70-1.81 (m, 2H), 3.34-3.43 (m , 2H) 3.54 (s, 9H), 3.93 (s, 9H), 7.14-7.70 (m, 12H). ¹³ C-NMR (125 MHz, CDCl ₃ ): δ = 10.1 (d, J _p− = 16.6 Hz), 16.6 (d, J _p− = 4.1 Hz), 26.0 (d, J _p- = 52.7 Hz), 50.8, 56.0, 109.0 (d, J _p- = 94.1 Hz), 116.2 (d, J _p- = 14.4 Hz), 135.5 ( _{d, J p- = 11.4Hz),} 164.6. ³¹ P-NMR (202 MHz, CDCl ₃ ): δ = 20.8. FAB-MS (positive): m / z = 515 ([M-I]). Elemental analysis: calculated value: C, 50.47; H, 5.65. Measurement: C, 50.43; H, 5.65.

(Example 6) (Production of catalyst 1)
A mixture of 2.32 g (1.00 mmol) of magnetite fine particles, 2.46 g (0.500 mmol) of tri-n-butyl [3- (trimethoxysilyl) propyl] phosphonium iodide, 50 ml of ethanol and 0.33 ml of water at room temperature. After ultrasonic stirring for 1 minute, the mixture was stirred at reflux for 12 hours. Only the magnetic material was separated by magnetic decantation using a neodymium magnet and washed 5 times with ethanol. The remaining magnetic fine particles were dried under reduced pressure to obtain 2.31 g of brown black fine particles. The elemental content of the fine particles obtained was found to have an iodine content of 1.84%.

(Example 7) (Production of catalyst 2)
A mixture of 2.76 g (11.9 mmol) of magnetite fine particles, 3.95 g (5.97 mmol) of tri-n-octyl [3- (trimethoxysilyl) propyl] phosphonium iodide, 50 ml of ethanol and 0.33 ml of water at room temperature. After ultrasonic stirring for 1 minute, the mixture was stirred at reflux for 12 hours. Only the magnetic material was separated by magnetic decantation using a neodymium magnet and washed twice with ethanol and three times with toluene. The remaining magnetic fine particles were dried under reduced pressure to obtain 2.57 g of brown black fine particles. The obtained fine particles were analyzed by halogen element analysis, and the iodine content was found to be 1.07%.

(Example 8) (Production of catalyst 3)
A mixture of 1.59 g (6.87 mmol) of magnetite fine particles, 1.90 g (3.44 mmol) of triphenyl [3- (trimethoxysilyl) propyl] phosphonium iodide, 50 ml of ethanol, and 0.33 ml of water was exceeded for 1 minute at room temperature. After sonic stirring, the mixture was stirred at reflux for 12 hours. Only the magnetic material was separated by magnetic decantation using a neodymium magnet and washed 5 times with ethanol. The remaining magnetic fine particles were dried under reduced pressure to obtain 1.63 g of brown black fine particles. The content of iodine was found to be 2.09% by halogen element analysis of the obtained fine particles.

(Example 9) (Production of catalyst 4)
A mixture of magnetite fine particles 2.32 g (1.00 mmol), tri (4-methoxyphenyl) [3- (trimethoxysilyl) propyl] phosphonium iodide 3.21 g (0.50 mmol), ethanol 50 ml, water 0.33 ml. The mixture was ultrasonically stirred at room temperature for 1 minute and then refluxed for 12 hours. Only the magnetic material was separated by magnetic decantation using a neodymium magnet and washed 5 times with ethanol. The remaining magnetic fine particles were dried under reduced pressure to obtain 2.24 g of brown black fine particles. The content of iodine was found to be 1.43% by halogen element analysis of the obtained fine particles.

(Example 10)
Sodium phenoxide trihydrate 128 mg (0.750 mol), catalyst 1 (155 mg, phosphonium salt 0.0225 mmol equivalent), 1-bromobutane 0.12 ml (1.13 mmol), toluene 1 ml, water 1 ml, tetradecane (20 μl: gas chromatography) The mixture was stirred at 100 ° C. for 12 hours in an oil bath. The yield of butylphenyl ether was determined by gas chromatography. The results are shown in Table 1.
(Examples 10 to 13)
The same operation as in Example 10 was performed except that the catalyst shown in Table 1 was used in place of the catalyst 1 in Example 10. The results are shown in Table 1.

(Comparative Example 1)
The same operation as in Example 10 was performed except that the catalyst 1 was omitted in Example 10. The results are shown in Table 1.

  As is clear from the results in Table 1, it was confirmed that the catalysts 1 to 4 have catalytic activity. Thus, it was confirmed that the magnetic fine particle-supported phosphonium salt of the present invention is an effective catalyst for the phase transfer reaction.

(Examples 14 to 16) (Reuse of catalyst)
After completion of the reaction in Example 12, the catalyst was collected on the wall of the reaction vessel by bringing a neodymium magnet into close contact with the outer wall of the reaction vessel. By decanting as it was, only the supernatant solution was transferred to another container. The catalyst remaining in the reaction vessel was washed with hexane and water three times, dried under reduced pressure, and then used for the production of butylphenyl ether under the same conditions as in Example 12. Table 2 shows the results of repeating these operations.

  From the results in Table 2, it was confirmed that the phase transfer catalyst supporting magnetic fine particles of the present invention was not only rapidly and easily separated and recovered by magnetism, but could be reused repeatedly.

The phosphonium salt carrying the magnetic fine particles of the present invention is not only rapidly and easily separated and recovered by magnetism, but also can be reused repeatedly, and thus is particularly useful in a phase transfer reaction that is an environmentally friendly organic synthesis reaction. It can be used for industrial production of many compounds.

Claims (4)

On the magnetic fine particles, the following general formula (1)

(In the formula, R ¹ represents a hydrocarbon group. R ² , R ³ , and R ⁴ each represents a hydrocarbon group, which may be bonded to each other to form a ring. X ⁻ represents an anion of an acid. And a siloxy group having a phosphonium salt moiety represented by formula (1). The following general formula (2)

(In the formula, R ¹ represents a hydrocarbon group. R ² , R ³ , and R ⁴ each represents a hydrocarbon group, which may be bonded to each other to form a ring. R ⁵ has 1 carbon number. represents the 3 alkyl groups .X ^-. is representing the anion of an acid) tri represented by alkoxy magnetic fine particles supported phosphonium according to claim 1, characterized by reacting a phosphonium salt and magnetic fine particles having a silyl group Method for producing salt.   A phase transfer catalyst comprising the phosphonium salt carrying magnetic fine particles according to claim 1. In phase transfer reaction, a method which comprises using a magnetic particulate support phosphonium salt according to claim 1, wherein the catalyst.