Process for synthesizing p-tertiary butyl benzaldehyde

Abstract

The invention discloses a method for synthesizing p-tert-butylbenzaldehyde. The method comprises the following steps: a normal atmosphere heterogeneous catalytic oxidation method is adopted; p-tert-butyltoluene as a raw material, sufficient oxygen as an oxygen source and n-hydroxyphthalimide as a free radical evocating agent in an acetonitrile solution react for 4 to 7 hours at a temperature between 50 and 70 DEG C under the condition of a catalyst to directly synthesize the p-tert-butylbenzaldehyde; and the catalyst is a cobalt-loaded mesoporous molecular sieve or a cobalt- and manganese-loaded mesoporous molecular sieve. The method use the cobalt-loaded mesoporous molecular sieve or the cobalt- and manganese-loaded mesoporous molecular sieve as the solid-phase catalyst; compared with the prior liquid-phase catalyst, the target product is easier to separate after reaction; a reactant can rapidly contact catalytic activity center; product molecules rapidly escape from a pore canal, thereby avoiding deep oxidation and improving the selectivity of aldehyde; in addition, micro n-hydroxyphthalimide as the free radical evocating agent is added to the system to trigger the chain transmission reaction of free radicals.

Description

(1) Technical field

[0001] The invention relates to a method for selectively oxidizing p-tert-butyl toluene to synthesize p-tert-butyl benzaldehyde under mild conditions. (2) Background technology

[0002] 4-tert-butylbenzaldehyde is an important intermediate in fine chemical products such as medicines, dyes, flavors and fragrances, and is in great demand in the synthesis of flavors and fragrances lyral.

[0003] There are many synthetic methods of p-tert-butylbenzaldehyde, and the traditional synthetic methods include stoichiometric oxidation and benzyl chloride hydrolysis. The stoichiometric oxidation method is in MnO 2 , concentrated H 2 SO 4 Directly oxidize p-tert-butyltoluene to synthesize p-tert-butylbenzaldehyde under the influence of the action. This process has equipment corrosion and serious pollution, and generates a large amount of MnSO 4 Disadvantages such as difficulty in recovery, high production cost, and difficulty in product separation. Although the b...

Examples

Embodiment 1

[0027] 2% Co-HMS preparation: According to Micromeritics ASAP2010 physical adsorption instrument, the pore volume of HMS is 0.95cm 3 / g, the pore volume of 3g pure silicon mesoporous molecular sieve HMS is 2.85cm 3 , it is calculated that the volume of ethanol to be added per 3 g of pure silicon mesoporous molecular sieve HMS is 2.85 mL. Assuming that the cobalt load is 2%, it is calculated that 3g of HMS needs to be added with Co(NO 3 ) 2 ·6H 2 O is 0.3024 g. 0.3024g Co(NO 3 ) 2 ·6H 2O was dissolved in 2.85mL ethanol to obtain impregnating solution A (concentration 7.8%). Add 3g of HMS, stir evenly, make it fully wet, soak at room temperature for 4 hours and then dry at 80°C for 12 hours. The impregnated sample was roasted at 550°C for 4h.

[0028] Oxidation reaction: Add 100mg2% of the above-prepared Co-HMS catalyst, 6ml of acetonitrile, 5mmol of p-tert-butyltoluene, and 0.25mmol of N-hydroxyphthalimide to a 25ml three-necked pear-shaped flask equipped with a reflux c...

Embodiment 2

[0030] 4% Co-HMS preparation: According to the Micromeritics ASAP2010 physical adsorption instrument, the pore volume of HMS is 0.95cm 3 / g, the pore volume of 3g pure silicon mesoporous molecular sieve HMS is 2.85cm 3 , it is calculated that the volume of ethanol to be added per 3 g of pure silicon mesoporous molecular sieve HMS is 2.85 mL. Set the cobalt loading as 4%, it is deduced that Co(NO 3 ) 2 ·6H 2 O is 0.6173g. 0.6173g Co(NO 3 ) 2 ·6H 2 O was dissolved in 2.85mL ethanol to obtain impregnation solution A (concentration 14.7%). Add 3g of HMS, stir evenly, make it fully wet, soak at room temperature for 4 hours and then dry at 80°C for 12 hours. The impregnated sample was roasted at 550°C for 4h.

[0031] Oxidation reaction: add 100mg4% Co-HMS catalyst, 6ml acetonitrile, 5mmol p-tert-butyltoluene, 0.25mmol N-hydroxyphthalimide (p-tert-butyl The mass ratio of toluene to N-hydroxyphthalimide to catalyst to acetonitrile is: 1:0.055:0.135:6.3), magnetically stirred,...

Embodiment 3

[0033] The preparation of 4% Co-HMS is the same as in Example 2.

[0034] Oxidation reaction: add 200mg4%Co-HMS catalyst, 8ml acetonitrile, 5mmol p-tert-butyltoluene, 0.5mmol N-hydroxyphthalimide (p-tert-butyl The mass ratio of methyl toluene and N-hydroxyphthalimide to catalyst and acetonitrile is: 1:0.11:0.27:8.4), magnetically stirred, heated in an oil bath at a constant temperature of 70°C, and introduced O 2 , O 2 The flow rate is 1.5ml / min, stop feeding O after 7h of reaction 2 , the reaction mixture was cooled, separated, and the product was analyzed by GC, and the results are listed in Table 1.

(1) Technical field

[0001] The invention relates to a method for selectively oxidizing p-tert-butyl toluene to synthesize p-tert-butyl benzaldehyde under mild conditions. (2) Background technology

[0002] 4-tert-butylbenzaldehyde is an important intermediate in fine chemical products such as medicines, dyes, flavors and fragrances, and is in great demand in the synthesis of flavors and fragrances lyral.

[0003] There are many synthetic methods of p-tert-butylbenzaldehyde, and the traditional synthetic methods include stoichiometric oxidation and benzyl chloride hydrolysis. The stoichiometric oxidation method is in MnO 2 , concentrated H 2 SO 4 Directly oxidize p-tert-butyltoluene to synthesize p-tert-butylbenzaldehyde under the influence of the action. This process has equipment corrosion and serious pollution, and generates a large amount of MnSO 4 Disadvantages such as difficulty in recovery, high production cost, and difficulty in product separation. Although the b...

Examples

Embodiment 1

[0027] 2% Co-HMS preparation: According to Micromeritics ASAP2010 physical adsorption instrument, the pore volume of HMS is 0.95cm 3 / g, the pore volume of 3g pure silicon mesoporous molecular sieve HMS is 2.85cm 3 , it is calculated that the volume of ethanol to be added per 3 g of pure silicon mesoporous molecular sieve HMS is 2.85 mL. Assuming that the cobalt load is 2%, it is calculated that 3g of HMS needs to be added with Co(NO 3 ) 2 ·6H 2 O is 0.3024 g. 0.3024g Co(NO 3 ) 2 ·6H 2O was dissolved in 2.85mL ethanol to obtain impregnating solution A (concentration 7.8%). Add 3g of HMS, stir evenly, make it fully wet, soak at room temperature for 4 hours and then dry at 80°C for 12 hours. The impregnated sample was roasted at 550°C for 4h.

[0028] Oxidation reaction: Add 100mg2% of the above-prepared Co-HMS catalyst, 6ml of acetonitrile, 5mmol of p-tert-butyltoluene, and 0.25mmol of N-hydroxyphthalimide to a 25ml three-necked pear-shaped flask equipped with a reflux c...

Embodiment 2

[0030] 4% Co-HMS preparation: According to the Micromeritics ASAP2010 physical adsorption instrument, the pore volume of HMS is 0.95cm 3 / g, the pore volume of 3g pure silicon mesoporous molecular sieve HMS is 2.85cm 3 , it is calculated that the volume of ethanol to be added per 3 g of pure silicon mesoporous molecular sieve HMS is 2.85 mL. Set the cobalt loading as 4%, it is deduced that Co(NO 3 ) 2 ·6H 2 O is 0.6173g. 0.6173g Co(NO 3 ) 2 ·6H 2 O was dissolved in 2.85mL ethanol to obtain impregnation solution A (concentration 14.7%). Add 3g of HMS, stir evenly, make it fully wet, soak at room temperature for 4 hours and then dry at 80°C for 12 hours. The impregnated sample was roasted at 550°C for 4h.

[0031] Oxidation reaction: add 100mg4% Co-HMS catalyst, 6ml acetonitrile, 5mmol p-tert-butyltoluene, 0.25mmol N-hydroxyphthalimide (p-tert-butyl The mass ratio of toluene to N-hydroxyphthalimide to catalyst to acetonitrile is: 1:0.055:0.135:6.3), magnetically stirred,...

Embodiment 3

[0033] The preparation of 4% Co-HMS is the same as in Example 2.

[0034] Oxidation reaction: add 200mg4%Co-HMS catalyst, 8ml acetonitrile, 5mmol p-tert-butyltoluene, 0.5mmol N-hydroxyphthalimide (p-tert-butyl The mass ratio of methyl toluene and N-hydroxyphthalimide to catalyst and acetonitrile is: 1:0.11:0.27:8.4), magnetically stirred, heated in an oil bath at a constant temperature of 70°C, and introduced O 2 , O 2 The flow rate is 1.5ml / min, stop feeding O after 7h of reaction 2 , the reaction mixture was cooled, separated, and the product was analyzed by GC, and the results are listed in Table 1.