Preparation method of pyridine-2-formaldehyde

Abstract

The invention discloses a preparation method of pyridine-2-formaldehyde. The preparation method comprises the following steps of: preparing a catalyst containing an acidity regulator and a transition metal oxide carried on a carrier; carrying out a gas-phase oxidizing reaction in a fixed bed catalytic reactor at 250-400 DEG C to generate a crude target product by using 2-picoline, oxygen and water as raw materials; extracting the crude product through dichloromethane and then decompressing and distilling extract liquor to remove the dichloromethane; and then rectifying to obtain a pure product with the pyridine-2-formaldehyde content higher than 98.5 percent. The method has simple preparation process, low raw material cost, high catalytic oxidation reaction selectivity, easy separation of main products and byproducts and high purity.

Description

technical field

[0001] The invention relates to a preparation method of medicine and chemical intermediate pyridine-2-carbaldehyde. Background technique

[0002] Pyridine-2-carbaldehyde is an important pharmaceutical intermediate and fine chemical raw material, which is mainly used to synthesize bisacodyl, a stimulant laxative. In addition, pyridine-2-carbaldehyde is also an intermediate in the synthesis of some molecules with special functions, such as fluorescent chelating agents and new neonicotinoid insecticides. The preparation method of existing pyridine-2-carboxaldehyde mainly contains following several: method one, under catalyst action, use O 2 , hydrogen peroxide, tert-butanol peroxide and other chemical oxidants to oxidize 2-pyridinemethanol to prepare pyridine-2-carboxaldehyde, (Tetrahedron Letters, 2006, 47 (6): 923-926; Advanced Synthesis & Catalysis, 2009, 351 (1 +2): 89-92) This method has the advantages of high yield and environmental protection, but the p...

Examples

Embodiment 1

[0015] 1) Mix 6.4g of ammonium metavanadate, 4.48g of ammonium molybdate, 0.64g of potassium nitrate, 19.3g of oxalic acid and 250mL of water, heat to 70°C, stir for 1 hour, add 57.6g of titanium dioxide, continue stirring for 1 hour, and cool to room temperature, stirred overnight, evaporated to dryness under reduced pressure, ground the obtained solid, added an appropriate amount of water and extruded into strips, baked at 90°C for 4 hours, and then calcined at 600°C for 8h to obtain a black strip catalyst, which was folded into 3 ~ 4mm strips for use.

[0016] 2) Put the black strip catalyst prepared in the previous step into a fixed bed reactor, keep the temperature of the fixed bed reactor at 400°C, feed oxygen and water into the fixed bed reactor, the speed of oxygen is 300mL / min, The speed of water is 0.2mL / min. After 1 hour, continue to feed oxygen and mass concentration in the fixed bed reactor and be the aqueous solution of 15% 2-picoline, the aqueous solution speed ...

Embodiment 2

[0018] 1) Mix 6.4g of ammonium metavanadate, 3.2g of chromium nitrate, 1.28g of potassium hydroxide, 12.8g of oxalic acid and 250mL of water, heat to 70°C, stir for 1 hour, add 48g of titanium dioxide, continue stirring for 1 hour, and cool to Stir overnight at room temperature, evaporate the water to dryness under reduced pressure, grind the resulting solid, add appropriate amount of water and extrude into strips, bake at 120°C for 3 hours, and then calcined at 700°C for 7 hours to obtain a black strip catalyst, which can be folded into 3~ 4mm strips for spare.

[0019] 2) Put the black strip catalyst prepared in the previous step into the fixed bed reactor, keep the temperature of the fixed bed reactor at 325°C, feed oxygen and water into the fixed bed reactor, the speed of oxygen is 200mL / min, The speed of water is 0.18mL / min, and after 1 hour, continue to feed oxygen and mass concentration in the fixed bed reactor and be the aqueous solution of 10% 2-picoline, the aqueous ...

Embodiment 3

[0021] 1) Mix 6.4g of ammonium metavanadate, 1.92g of ammonium permanganate, 1.93g of sodium nitrate, 6.4g of oxalic acid and 250mL of water, heat to 70°C, stir for 1 hour, add 38.4g of titanium dioxide, and continue stirring for 1 hour, Cool to room temperature, stir overnight, evaporate the water under reduced pressure, grind the obtained solid, add appropriate amount of water and extrude into strips, bake at 150°C for 2 hours, and then calcined at 800°C for 6 hours to obtain a black strip catalyst, which is folded into 3 ~ 4mm small strips for use.

[0022] 2) Put the black strip catalyst prepared in the previous step into a fixed bed reactor, keep the temperature of the fixed bed reactor at 250°C, feed oxygen and water into the fixed bed reactor, the speed of oxygen is 100mL / min, The speed of water is 0.14mL / min. After 1 hour, continue to feed oxygen and mass concentration in the fixed bed reactor and be the aqueous solution of 5% 2-picoline, the aqueous solution speed of ...

technical field

[0001] The invention relates to a preparation method of medicine and chemical intermediate pyridine-2-carbaldehyde. Background technique

[0002] Pyridine-2-carbaldehyde is an important pharmaceutical intermediate and fine chemical raw material, which is mainly used to synthesize bisacodyl, a stimulant laxative. In addition, pyridine-2-carbaldehyde is also an intermediate in the synthesis of some molecules with special functions, such as fluorescent chelating agents and new neonicotinoid insecticides. The preparation method of existing pyridine-2-carboxaldehyde mainly contains following several: method one, under catalyst action, use O 2 , hydrogen peroxide, tert-butanol peroxide and other chemical oxidants to oxidize 2-pyridinemethanol to prepare pyridine-2-carboxaldehyde, (Tetrahedron Letters, 2006, 47 (6): 923-926; Advanced Synthesis & Catalysis, 2009, 351 (1 +2): 89-92) This method has the advantages of high yield and environmental protection, but the p...

Examples

Embodiment 1

[0015] 1) Mix 6.4g of ammonium metavanadate, 4.48g of ammonium molybdate, 0.64g of potassium nitrate, 19.3g of oxalic acid and 250mL of water, heat to 70°C, stir for 1 hour, add 57.6g of titanium dioxide, continue stirring for 1 hour, and cool to room temperature, stirred overnight, evaporated to dryness under reduced pressure, ground the obtained solid, added an appropriate amount of water and extruded into strips, baked at 90°C for 4 hours, and then calcined at 600°C for 8h to obtain a black strip catalyst, which was folded into 3 ~ 4mm strips for use.

[0016] 2) Put the black strip catalyst prepared in the previous step into a fixed bed reactor, keep the temperature of the fixed bed reactor at 400°C, feed oxygen and water into the fixed bed reactor, the speed of oxygen is 300mL / min, The speed of water is 0.2mL / min. After 1 hour, continue to feed oxygen and mass concentration in the fixed bed reactor and be the aqueous solution of 15% 2-picoline, the aqueous solution speed ...

Embodiment 2

[0018] 1) Mix 6.4g of ammonium metavanadate, 3.2g of chromium nitrate, 1.28g of potassium hydroxide, 12.8g of oxalic acid and 250mL of water, heat to 70°C, stir for 1 hour, add 48g of titanium dioxide, continue stirring for 1 hour, and cool to Stir overnight at room temperature, evaporate the water to dryness under reduced pressure, grind the resulting solid, add appropriate amount of water and extrude into strips, bake at 120°C for 3 hours, and then calcined at 700°C for 7 hours to obtain a black strip catalyst, which can be folded into 3~ 4mm strips for spare.

[0019] 2) Put the black strip catalyst prepared in the previous step into the fixed bed reactor, keep the temperature of the fixed bed reactor at 325°C, feed oxygen and water into the fixed bed reactor, the speed of oxygen is 200mL / min, The speed of water is 0.18mL / min, and after 1 hour, continue to feed oxygen and mass concentration in the fixed bed reactor and be the aqueous solution of 10% 2-picoline, the aqueous ...

Embodiment 3

[0021] 1) Mix 6.4g of ammonium metavanadate, 1.92g of ammonium permanganate, 1.93g of sodium nitrate, 6.4g of oxalic acid and 250mL of water, heat to 70°C, stir for 1 hour, add 38.4g of titanium dioxide, and continue stirring for 1 hour, Cool to room temperature, stir overnight, evaporate the water under reduced pressure, grind the obtained solid, add appropriate amount of water and extrude into strips, bake at 150°C for 2 hours, and then calcined at 800°C for 6 hours to obtain a black strip catalyst, which is folded into 3 ~ 4mm small strips for use.

[0022] 2) Put the black strip catalyst prepared in the previous step into a fixed bed reactor, keep the temperature of the fixed bed reactor at 250°C, feed oxygen and water into the fixed bed reactor, the speed of oxygen is 100mL / min, The speed of water is 0.14mL / min. After 1 hour, continue to feed oxygen and mass concentration in the fixed bed reactor and be the aqueous solution of 5% 2-picoline, the aqueous solution speed of ...