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Preparation method of pyridine-2-formaldehyde

A technology of formaldehyde and pyridine, which is applied in the field of preparation of pharmaceutical and chemical intermediate pyridine-2-carbaldehyde, can solve the problems of cumbersome preparation method, low yield, and high price of 2-cyanopyridine, and achieve simple preparation process, selectable High stability and easy separation effect

Inactive Publication Date: 2010-09-01
ZHEJIANG UNIV
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  • Abstract
  • Description
  • Claims
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Problems solved by technology

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 preparation method of the raw material 2-pyridinemethanol used is relatively cumbersome; method 2, Shen Dadong et al. used trichloroisocyanuric acid and 2-picoline Be raw material, benzamide is catalyst, make pyridine-2-carboxaldehyde, (Chinese Journal of Pharmaceutical Industry, 2006,37 (7): 448), total yield is up to 88%, but will use oleum in the process, Corrosion is strong; method three, catalytic reduction method using H 2 2-cyanopyridine is catalytically reduced to 2-pyridine formaldehyde, (Chinese Journal of Pharmaceutical Industry, 2007, (7): 480-480), but the price of raw material 2-cyanopyridine is expensive; method four, oxygen gas phase oxidation method, After gasification, 2-picoline is mixed with oxygen and water vapor, and directly oxidized to pyridine-2-carbaldehyde through a fixed-bed reactor equipped with a catalyst, (Journal of Chemical Engineering of Universities and Colleges. 2002, 16(4): 436-440 ), the catalyst used is a carrier with alkaline bentonite or silica gel, and vanadium and molybdenum are active components. The selectivity of this method reaction is 80% to 90%, and the conversion rate of 2-picoline has only 50% to 58%. resulting in a low final yield

Method used

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Examples

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Comparison scheme
Effect test

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 ...

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PUM

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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...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07D213/48
Inventor 戴立言俞杰王晓钟陈英奇
Owner ZHEJIANG UNIV
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