Preparation method of pyridine-2-formaldehyde

A formaldehyde and pyridine technology, which is applied in the field of pyridine-2-carbaldehyde preparation, can solve the problems of cumbersome preparation methods, low final yield, long process route, etc., and achieve the effects of simple preparation process, low raw material cost and high product purity

Inactive Publication Date: 2011-11-16
ZHEJIANG UNIV
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Problems solved by technology

The preparation method of existing pyridine-2-carbaldehyde mainly contains the following several kinds of preparation methods of existing pyridine-2-carbaldehyde: 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, He Yimin et al. used trichloroisocyanate and 2-picoline as raw materials , benzamide is used as a catalyst to obtain pyridine-2-carbaldehyde, (CN101906068, 2010), the process route is long, the process is cumbersome, and the total yield is low; method three, the catalytic reduction method uses H 2 Catalytic reduction of 2-cyanopyridine to 2-pyridinecarbaldehyde (China Pharmaceutical Industry Journal, 2007, (7): 480-480), but the price of raw material 2-cyanopyridine is expensive; method four, oxygen gas phase oxidation method, This method has a great advantage over other methods because there is only one step in the reaction, the product separation is simple, and the catalyst can be reused.
The 2-picoline is vaporized and mixed with oxygen and water vapor, and then directly oxidized to pyridine-2-carbaldehyde through a fixed-bed reactor equipped with a catalyst, (Journal of Chemical Engineering of Chinese Universities. 2002, 16(4): 436- 440), the catalyst used is alkaline bentonite or silica gel as the carrier, and vanadium and molybdenum are the active components. The selectivity of this method is 80%~90%, and the conversion rate of 2-picoline is only 50%~58%. , leading to a low final yield

Method used

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Experimental program
Comparison scheme
Effect test

Embodiment 1

[0011] Dissolve 8.0g of ammonium molybdate, 14.4g of bismuth nitrate, 1.6g of ferric nitrate, 4g of sodium nitrate and 16.0g of oxalic acid in 450ml of water, heat to 70°C, add 96g of titanium dioxide, stir and mix evenly, and evaporate the water under reduced pressure. The obtained solid was ground, added with appropriate amount of water and extruded into strips, baked at 120°C for 2 hours, and then calcined at 600°C for 8 hours to obtain a black strip catalyst, which was folded into 3-4 mm for use.

[0012] Put the black strip catalyst prepared in the previous step into a fixed bed reactor, keep the temperature of the fixed bed reactor at 350℃, and feed oxygen and water into the fixed bed reactor at a rate of 250 mL / min. The speed is 0.2mL / min. After 1 hour, oxygen and an aqueous solution of 2-methylpyridine with a mass concentration of 20% are continuously fed into the fixed bed reactor. The rate of the aqueous solution of 2-methylpyridine is 0.2mL / min. The gas phase oxidation...

Embodiment 2

[0014] Dissolve 8.0g of ammonium molybdate, 8.8g of bismuth nitrate, 2.0g of cobalt nitrate, 2.4g of sodium hydroxide and 12.0g of citric acid in 450ml of water, heat to 60℃, add 84g of titanium dioxide, stir and mix well, and evaporate the water under reduced pressure Afterwards, the obtained solid was ground, and an appropriate amount of water was added to squeeze into a strip, then baked at 100°C for 3 hours, and then calcined at 500°C for 9 hours to obtain a black strip catalyst, which was folded into 3-4 mm for use.

[0015] Put the black strip catalyst prepared in the previous step into a fixed bed reactor, keep the temperature of the fixed bed reactor at 320℃, and feed oxygen and water into the fixed bed reactor at a rate of 200 mL / min. The speed is 0.18mL / min. After 1 hour, oxygen and the aqueous solution of 2-methylpyridine with a mass concentration of 10% are continuously fed into the fixed bed reactor. The speed of the aqueous solution of 2-methylpyridine is 0.18mL / min....

Embodiment 3

[0017] Dissolve 8.0g of ammonium molybdate, 2.4g of bismuth nitrate, 4.0g of chromium nitrate, 0.8g of potassium nitrate and 8.0g of tartaric acid in 450ml of water, heat to 80°C, add 72g of titanium dioxide, stir and mix well, and evaporate the water under reduced pressure. Grind the obtained solid, add an appropriate amount of water and squeeze into strips, bake at 80°C for 4 hours, and then calcinate at 400°C for 10 hours to obtain a black strip catalyst, which is folded into 3-4 mm for use.

[0018] 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℃, and feed oxygen and water into the fixed-bed reactor at a rate of 100 mL / min. The speed is 0.10mL / min. After 1 hour, oxygen and an aqueous solution of 2-methylpyridine with a mass concentration of 5% are continuously fed into the fixed bed reactor. The speed of the aqueous solution of 2-methylpyridine is 0.10mL / min. Carry out gas phase oxidati...

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Abstract

The invention relates to a preparation method of pyridine-2-formaldehyde. The preparation method comprises the following two steps: preparing an acidity-regulator-containing supported catalyst with titanium dioxide used as a carrier, molybdenum bismuth oxide used as a main body and transition metal oxide used as an auxiliary, carrying out gas-phase oxidation reaction on 2-methyl pyridine, oxygen and water used as raw materials in a fixed bed catalytic reactor at 250-350 DEG C to obtain a crude pyridine-2-formaldehyde product, extracting the crude product with dichloromethane, carrying out pressure-reduced distillation on the extract to remove dichloromethane, and then rectifying to obtain a pure product with a pyridine-2-formaldehyde content more than 98%. The preparation method provided by the invention has the advantages of simple preparation process, high efficiency, low cost, high catalytic reaction activity and selectivity, easy separation of main products and by-products and high purity.

Description

Technical field [0001] The invention relates to a preparation method of pyridine-2-carbaldehyde. Background technique [0002] Pyridine-2-carboxaldehyde is an important pharmaceutical intermediate and fine chemical raw material. It is mainly used to synthesize the laxative bisacodyl. In addition, it is also used to synthesize new nicotinic insecticides and some molecules with special functions such as fluorescent chelating agents. Recently, there are related applications in the synthesis of new materials and chiral catalysts. The existing preparation methods of pyridine-2-carbaldehyde mainly include the following methods: Method one, use O under the action of a catalyst 2 , Hydrogen peroxide, tert-butanol and other chemical oxidants to oxidize 2-pyridine methanol 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 t...

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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