A kind of mn(Ⅲ)-salen catalyst and its preparation method and application

Abstract

The invention discloses a Mn(III)-Salen catalyst as well as a preparation method and application thereof. The method comprises the following steps: performing reaction on 5-bromo-3-tert-butyl salicylaldehyde and pyridine-4-boric acid as raw materials to generate pyridine salicylaldehyde derivatives; reacting the pyridine salicylaldehyde derivatives with ethylene diamine to synthesize a Salen ligand with a pyridine functional group; finally coordinating divalent manganese salt with the Salen ligand, oxidizing, evaporating an obtained reaction solution to dryness, washing by water and filtering to obtain the Mn(III)-Salen catalyst. According to the method, a reaction system is simple, a reagent is easily available and low in cost, a reaction product post-treatment process is simple, the product purity is high, and the obtained Mn(III)-Salen catalyst is stable to water and air and capable of catalyzing styrene, 4-tert-butyl styrene, indene, alpha-methyl styrene and the like in a manner of relatively high activity and selectivity to synthesize olefin epoxides.

Description

technical field

[0001] The invention belongs to the technical field of catalysts, and in particular relates to a Mn(III)-Salen catalyst, a preparation method thereof, and an application of catalytic olefin epoxidation. Background technique

[0002] Salen is the abbreviation of N,N-bis-(saliylaldehyde)ethylendiamine compound. The Salen metal complex is obtained by condensation reaction of salicylaldehyde derivative and diamine, and then complexed with different metal ions. The common synthetic route is as follows :

[0003] .

[0004] Salen metal complexes have the characteristics of simple synthetic route, low cost, easy preparation, and high yield. They can also change the structure of the Salen catalyst by adjusting the 3,5-position substituent. For example, the change of the electronic effect of the 5-position substituent can make Salen The ligand has an electron-donating or electron-accepting effect, and the 3-position substitution can endow the Salen ligand with a s...

Examples

preparation example Construction

[0035] A kind of preparation method of Mn (Ⅲ)-Salen catalyst, comprises the following steps:

[0036] 1) Add 5-bromo-3-tert-butylsalicylaldehyde, pyridine-4-boronic acid, palladium salt, inorganic base and 70~200mL solvent a to a 500mL three-necked flask in sequence, at 60~100℃, inert gas protection After reaction for 12~24h; after the reaction is completed, cool to room temperature, and use 10~50mLCH 2 Cl 2 Extract 3 to 5 times, combine the lower layer extracts, add anhydrous Na to the lower layer extracts 2 SO 4 or anhydrous MgSO 4 Stir for 10~30min, stand still for 3~5min and then filter with suction. After the filtrate is concentrated to 2~5mL at 25~40℃, perform column chromatography with 300~500 mesh silica gel to obtain compound A; the chemical structure of compound A is as follows :

[0037] ;

[0038] 2) Add compound A, ethylenediamine and 70~150mL solvent b to a 250mL three-necked flask in sequence, and react at 70~100°C for 12~24h under the protection of an ine...

Embodiment 1

[0051] Example 1. Synthesis of Compound A (4-(4-pyridine)-3-tert-butyl salicylaldehyde)

[0052] Mix 160mL of dioxane and 40mL of water to make solvent a; add 5g, 25mmol of 5-bromo-3-tert-butyl salicylaldehyde, 3.69g, 30mmol of pyridine-4-boronic acid in sequence to a 500mL three-necked flask , 1.16g, 1mmol of Pd(PPh 3 ) 4 , 8.29g, 60mmol of K 2 CO 3 and 70mL solvent a, reacted at 85°C for 12h under the protection of inert gas nitrogen; after the reaction was completed, cool to room temperature, and 2 Cl 2 Extract 3 times, combine the lower layer extracts, add anhydrous Na to the lower layer extracts 2 SO 4 Stir for 10 minutes, stand still for 3 minutes and then filter with suction. After the filtrate was concentrated to 2 mL at 40 ° C, column chromatography was performed with 300-500 mesh silica gel, and the eluent was ethyl acetate / n-hexane = 1:20, and 4.22 g was isolated , A light yellow solid with a purity of 99.5%. 1 HNMR (CD 3 Cl, 400MHz) δ (ppm): 1.50 [s, 9H, C...

Embodiment 2

[0053] Example 2. Synthesis of Compound A (4-(4-pyridine)-3-tert-butyl salicylaldehyde)

[0054] Mix 160mL tetrahydrofuran with 40mL water to make solvent a; add 5g, 25mmol of 5-bromo-3-tert-butyl salicylaldehyde, 3.69g, 30mmol of pyridine-4-boronic acid, 0.816g, 1mmol of Pd(dppf) 2 Cl 2 , 6.63g, 60mmol of Na 2 CO 3 and 100mL solvent a, react at 60°C under the protection of inert gas helium for 16h; after the reaction is completed, cool to room temperature, 2 Cl 2 Extract 2 times, combine the lower layer extracts, add anhydrous Na to the lower layer extracts 2 SO 4 Stir for 20 minutes, let it stand for 4 minutes, and filter it with a Buchner funnel. Concentrate the filtrate to 5 mL at 25°C, and perform column chromatography with 300-500 mesh silica gel. The eluent is ethyl acetate / n-hexane=1:20, 3.58 g of a pale yellow solid with a purity of 99.5% were isolated. 1 HNMR (CD 3 Cl, 400MHz) δ (ppm): 1.50 [s, 9H, C (CH 3 ) 3 ], 7.50(d, J=6Hz, 2H), 7.72(s, 1H), 7.83(s, 1H...

technical field

[0001] The invention belongs to the technical field of catalysts, and in particular relates to a Mn(III)-Salen catalyst, a preparation method thereof, and an application of catalytic olefin epoxidation. Background technique

[0002] Salen is the abbreviation of N,N-bis-(saliylaldehyde)ethylendiamine compound. The Salen metal complex is obtained by condensation reaction of salicylaldehyde derivative and diamine, and then complexed with different metal ions. The common synthetic route is as follows :

[0003] .

[0004] Salen metal complexes have the characteristics of simple synthetic route, low cost, easy preparation, and high yield. They can also change the structure of the Salen catalyst by adjusting the 3,5-position substituent. For example, the change of the electronic effect of the 5-position substituent can make Salen The ligand has an electron-donating or electron-accepting effect, and the 3-position substitution can endow the Salen ligand with a s...

Examples

preparation example Construction

[0035] A kind of preparation method of Mn (Ⅲ)-Salen catalyst, comprises the following steps:

[0036] 1) Add 5-bromo-3-tert-butylsalicylaldehyde, pyridine-4-boronic acid, palladium salt, inorganic base and 70~200mL solvent a to a 500mL three-necked flask in sequence, at 60~100℃, inert gas protection After reaction for 12~24h; after the reaction is completed, cool to room temperature, and use 10~50mLCH 2 Cl 2 Extract 3 to 5 times, combine the lower layer extracts, add anhydrous Na to the lower layer extracts 2 SO 4 or anhydrous MgSO 4 Stir for 10~30min, stand still for 3~5min and then filter with suction. After the filtrate is concentrated to 2~5mL at 25~40℃, perform column chromatography with 300~500 mesh silica gel to obtain compound A; the chemical structure of compound A is as follows :

[0037] ;

[0038] 2) Add compound A, ethylenediamine and 70~150mL solvent b to a 250mL three-necked flask in sequence, and react at 70~100°C for 12~24h under the protection of an ine...

Embodiment 1

[0051] Example 1. Synthesis of Compound A (4-(4-pyridine)-3-tert-butyl salicylaldehyde)

[0052] Mix 160mL of dioxane and 40mL of water to make solvent a; add 5g, 25mmol of 5-bromo-3-tert-butyl salicylaldehyde, 3.69g, 30mmol of pyridine-4-boronic acid in sequence to a 500mL three-necked flask , 1.16g, 1mmol of Pd(PPh 3 ) 4 , 8.29g, 60mmol of K 2 CO 3 and 70mL solvent a, reacted at 85°C for 12h under the protection of inert gas nitrogen; after the reaction was completed, cool to room temperature, and 2 Cl 2 Extract 3 times, combine the lower layer extracts, add anhydrous Na to the lower layer extracts 2 SO 4 Stir for 10 minutes, stand still for 3 minutes and then filter with suction. After the filtrate was concentrated to 2 mL at 40 ° C, column chromatography was performed with 300-500 mesh silica gel, and the eluent was ethyl acetate / n-hexane = 1:20, and 4.22 g was isolated , A light yellow solid with a purity of 99.5%. 1 HNMR (CD 3 Cl, 400MHz) δ (ppm): 1.50 [s, 9H, C...

Embodiment 2

[0053] Example 2. Synthesis of Compound A (4-(4-pyridine)-3-tert-butyl salicylaldehyde)

[0054] Mix 160mL tetrahydrofuran with 40mL water to make solvent a; add 5g, 25mmol of 5-bromo-3-tert-butyl salicylaldehyde, 3.69g, 30mmol of pyridine-4-boronic acid, 0.816g, 1mmol of Pd(dppf) 2 Cl 2 , 6.63g, 60mmol of Na 2 CO 3 and 100mL solvent a, react at 60°C under the protection of inert gas helium for 16h; after the reaction is completed, cool to room temperature, 2 Cl 2 Extract 2 times, combine the lower layer extracts, add anhydrous Na to the lower layer extracts 2 SO 4 Stir for 20 minutes, let it stand for 4 minutes, and filter it with a Buchner funnel. Concentrate the filtrate to 5 mL at 25°C, and perform column chromatography with 300-500 mesh silica gel. The eluent is ethyl acetate / n-hexane=1:20, 3.58 g of a pale yellow solid with a purity of 99.5% were isolated. 1 HNMR (CD 3 Cl, 400MHz) δ (ppm): 1.50 [s, 9H, C (CH 3 ) 3 ], 7.50(d, J=6Hz, 2H), 7.72(s, 1H), 7.83(s, 1H...