CN102241624B - Preparation method of pyridine-2-formaldehyde - Google Patents

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

The preparation method of pyridine-2-formaldehyde

Technical field

The present invention relates to the preparation method of pyridine-2-formaldehyde.

Background technology

Pyridine-2-formaldehyde is a kind of important medicine intermediate and fine chemical material, and it is mainly used in synthetic caccagogue bisacodyl.In addition, also be used for the synthesizing new nicotinic insecticide and have molecule such as the fluorescent chelating agent etc. of specific function with some.Recently, aspect synthetic novel material and the chiral catalyst related application is being arranged also.The preparation method that the preparation method of existing pyridine-2-formaldehyde mainly contains existing pyridine-2-formaldehyde mainly contains following several kinds: method one, under catalyst action, use O ₂, chemical oxidizing agent oxidation 2-piconol such as hydrogen peroxide, tertbutanol peroxide prepares pyridine-2-formaldehyde, (Tetrahedron Letters, 2006,47 (6): 923 – 926; Advanced Synthesis & Catalysis, 2009,351 (1+2): 89-92) this method has the advantage of productive rate height, environmental protection, but the preparation method of used raw material 2-piconol is more loaded down with trivial details; Method two, He Yimin etc. are raw material with three chlorine isocyanates and 2-picoline, BM is a catalyzer, makes pyridine-2-formaldehyde, (CN101906068,2010), and this operational path is long, and process is loaded down with trivial details, and total recovery is lower; Method three, catalytic reduction method are promptly used H ₂With 2-cyanopyridine catalytic reduction is the 2-pyridylaldehyde, (Chinese Journal of Pharmaceuticals, 2007, (7): 480-480), but the costing an arm and a leg of raw material 2-cyanopyridine; Method four, the oxygen vapour phase oxidation process, this method is because reaction has only a step, and product separation is simple, and catalyzer is reusable, so than additive method bigger advantage is arranged.2-picoline gasification back is mixed with oxygen and water vapour, and through the fixed-bed reactor of catalyzer are housed, direct oxidation is a pyridine-2-formaldehyde; (colleges and universities' chemical engineering journal. 2002,16 (4): 436-440), catalyst system therefor is a carrier with alkaline bentonite or silica gel; Vanadium, molybdenum are active constituent; The selectivity of this method reaction is 80% ~ 90%, and the transformation efficiency of 2-picoline has only 50% ~ 58%, has caused ultimate yield on the low side.

Summary of the invention

The objective of the invention is to develop a kind of efficient, lower-cost and have a preparation method of the pyridine-2-formaldehyde of industrial applications prospect.

The preparation method of pyridine-2-formaldehyde of the present invention may further comprise the steps:

The first step is made into the aqueous solution with ammonium molybdate, Bismuth trinitrate, transition metal mixtures, acidity regulator and organic complexing agent, is heated to 60～80 ℃, adds titanium oxide then; Mix, behind the evaporated under reduced pressure moisture, the gained solid is ground; Add again after suitable quantity of water is extruded into strip, smoked 2 ~ 4 hours in 80-120 ℃, then in 400 ~ 600 ℃ of calcinings 8 ~ 10 hours; Obtain strip catalyst; The weight ratio of used titanium oxide and ammonium molybdate is 9 ~ 12:1, and the weight ratio of used Bismuth trinitrate and ammonium molybdate is 0.3 ~ 1.8:1, and the weight ratio of transition metal mixtures and ammonium molybdate is 0.2 ~ 0.5:1; The mass ratio of acidity regulator and ammonium molybdate is 0.1 ~ 0.5:1, and the weight ratio of organic complexing agent and ammonium molybdate is 1 ~ 2:1;

Second step will be gone up the catalyzer that makes of step and put into fixed-bed reactor; The fixed bed reaction actuator temperature is remained on 250 ~ 350 ℃; To fixed-bed reactor aerating oxygen and water after 1 hour, in fixed-bed reactor, continue aerating oxygen and mass concentration again and be 5 ~ 20% the 2-picoline aqueous solution, under 250 ~ 350 ℃, carry out gas phase oxidation; Generate the thick product aqueous solution of pyridine-2-formaldehyde; The thick product aqueous solution is through dichloromethane extraction, and methylene dichloride is removed in the extraction liquid underpressure distillation, and rectifying obtains pure article then; The speed of above-mentioned aerating oxygen is 100 ~ 250mL/min, the input speed of water and oxygen than and the input speed ratio of the 2-picoline aqueous solution and oxygen be 1:1000 ~ 1250.

Among the present invention; Used transition metal salt is iron nitrate, Xiao Suangu, nickelous nitrate, manganous nitrate or chromium nitrate; Acidity regulator is saltpetre, Pottasium Hydroxide, salt of wormwood, SODIUMNITRATE, sodium hydroxide or yellow soda ash, and organic complexing agent is oxalic acid, Hydrocerol A or tartrate.

Preparation technology of the present invention is simple, and raw materials cost is low, and reaction conversion ratio and selectivity are high, and product is easy to separate, and the finished product purity is high, has stronger industrial applications and is worth.

Embodiment

Further specify the present invention below in conjunction with embodiment.

Embodiment 1

8.0g ammonium molybdate, 14.4g Bismuth trinitrate, 1.6g iron nitrate, 4g SODIUMNITRATE and 16.0g oxalic acid are dissolved in 450ml water, are heated to 70 ℃, add titanium oxide 96g; Mix, behind the evaporated under reduced pressure moisture, the gained solid is ground; Add again after suitable quantity of water is extruded into strip, smoked 2 hours in 120 ℃, then in 600 ℃ of calcinings 8 hours; Obtain the black strip catalyst, it is subsequent use to be converted into 3-4mm.

The black strip catalyst that the last step makes is put into fixed-bed reactor, the fixed bed reaction actuator temperature is remained on 350 ℃, to fixed-bed reactor aerating oxygen and water; The speed of oxygen is 250mL/min, and the speed of water is 0.2mL/min, after 1 hour; In fixed-bed reactor, continue aerating oxygen and mass concentration and be the aqueous solution of 20% 2-picoline, the aqueous solution speed of 2-picoline is 0.2mL/min, under 350 ℃, carries out gas phase oxidation; Generate the pyridine-2-formaldehyde crude product aqueous solution; The crude product aqueous solution is through dichloromethane extraction, and methylene dichloride is removed in the extraction liquid underpressure distillation, and rectifying obtains content pure article more than 98% then; Transformation efficiency 96.8 % of 2-picoline, selectivity 92.2 % of pyridine-2-formaldehyde.

Embodiment 2

8.0g ammonium molybdate, 8.8g Bismuth trinitrate, 2.0g Xiao Suangu, 2.4g sodium hydroxide and 12.0g Hydrocerol A are dissolved in 450ml water, are heated to 60 ℃, add titanium oxide 84g; Mix, behind the evaporated under reduced pressure moisture, the gained solid is ground; Add again after suitable quantity of water is extruded into strip, smoked 3 hours in 100 ℃, then in 500 ℃ of calcinings 9 hours; Obtain the black strip catalyst, it is subsequent use to be converted into 3-4mm.

The black strip catalyst that the last step makes is put into fixed-bed reactor, the fixed bed reaction actuator temperature is remained on 320 ℃, to fixed-bed reactor aerating oxygen and water; The speed of oxygen is 200mL/min, and the speed of water is 0.18mL/min, after 1 hour; In fixed-bed reactor, continue aerating oxygen and mass concentration and be the aqueous solution of 10% 2-picoline, the aqueous solution speed of 2-picoline is 0.18mL/min, under 320 ℃, carries out gas phase oxidation; Generate the pyridine-2-formaldehyde crude product aqueous solution; The crude product aqueous solution is through dichloromethane extraction, and methylene dichloride is removed in the extraction liquid underpressure distillation, and rectifying obtains content pure article more than 98% then; Transformation efficiency 96.1 % of 2-picoline, selectivity 90.2 % of pyridine-2-formaldehyde.

Embodiment 3

8.0g ammonium molybdate, 2.4g Bismuth trinitrate, 4.0g chromium nitrate, 0.8g saltpetre and 8.0g tartrate are dissolved in 450ml water, are heated to 80 ℃, add titanium oxide 72g; Mix, behind the evaporated under reduced pressure moisture, the gained solid is ground; Add again after suitable quantity of water is extruded into strip, smoked 4 hours in 80 ℃, then in 400 ℃ of calcinings 10 hours; Obtain the black strip catalyst, it is subsequent use to be converted into 3-4mm.

The black strip catalyst that the last step makes is put into fixed-bed reactor, the fixed bed reaction actuator temperature is remained on 250 ℃, to fixed-bed reactor aerating oxygen and water; The speed of oxygen is 100mL/min, and the speed of water is 0.10mL/min, after 1 hour; In fixed-bed reactor, continue aerating oxygen and mass concentration and be the aqueous solution of 5% 2-picoline, the aqueous solution speed of 2-picoline is 0.10mL/min, under 250 ℃, carries out gas phase oxidation; Generate the pyridine-2-formaldehyde crude product aqueous solution; The crude product aqueous solution is through dichloromethane extraction, and methylene dichloride is removed in the extraction liquid underpressure distillation, and rectifying obtains content pure article more than 98% then; Transformation efficiency 95.3 % of 2-picoline, the selectivity 88.8% of pyridine-2-formaldehyde.

Claims (1)

1. the preparation method of a pyridine-2-formaldehyde in turn includes the following steps:

The first step is made into the aqueous solution with ammonium molybdate, Bismuth trinitrate, transition metal mixtures, acidity regulator and organic complexing agent, is heated to 60～80 ℃, adds titanium oxide then; Mix, behind the evaporated under reduced pressure moisture, the gained solid is ground; Add again after suitable quantity of water is extruded into strip, smoked 2 ~ 4 hours in 80-120 ℃, then in 400 ~ 600 ℃ of calcinings 8 ~ 10 hours; Obtain strip catalyst; The weight ratio of used titanium oxide and ammonium molybdate is 9 ~ 12:1, and the weight ratio of used Bismuth trinitrate and ammonium molybdate is 0.3 ~ 1.8:1, and the weight ratio of transition metal mixtures and ammonium molybdate is 0.2 ~ 0.5:1; The mass ratio of acidity regulator and ammonium molybdate is 0.1 ~ 0.5:1, and the weight ratio of organic complexing agent and ammonium molybdate is 1 ~ 2:1; Above-mentioned transition metal mixtures is iron nitrate, Xiao Suangu, nickelous nitrate, manganous nitrate or chromium nitrate; Acidity regulator is saltpetre, Pottasium Hydroxide, salt of wormwood, SODIUMNITRATE, sodium hydroxide or yellow soda ash; Organic complexing agent is oxalic acid, Hydrocerol A or tartrate;

Second step will be gone up the catalyzer that makes of step and put into fixed-bed reactor; The fixed bed reaction actuator temperature is remained on 250 ~ 350 ℃; To fixed-bed reactor aerating oxygen and water after 1 hour, in fixed-bed reactor, continue aerating oxygen and mass concentration again and be 5 ~ 20% the 2-picoline aqueous solution, under 250 ~ 350 ℃, carry out gas phase oxidation; Generate the thick product aqueous solution of pyridine-2-formaldehyde; The thick product aqueous solution is through dichloromethane extraction, and methylene dichloride is removed in the extraction liquid underpressure distillation, and rectifying obtains pure article then; The speed of above-mentioned aerating oxygen is 100 ~ 250mL/min, the input speed of water and oxygen than and the input speed ratio of the 2-picoline aqueous solution and oxygen be 1:1000 ~ 1250.