METHOD FOR PREPARING 2,2'-DIPYRIDINE AND DERIVATIVES THEREOF

Abstract

Disclosed is a method for preparing 2,2-dipyridine and derivatives thereof. The method includes: using pyridine represented by formula I or a derivative thereof as a raw material to generate 2,2-dipyridine represented by formula II by performing dehydrogenative coupling under the action of a supported catalyst in the presence of additives, where R is H, C.sub.1-C.sub.2 alkyl, Cl, or Br. The method of the present invention features wide adaptability to raw materials, high atomic utilization rate, high catalyst activity, long service life, and fewer by-products.

Claims

1. A method for preparing 2,2-dipyridine and derivatives thereof, wherein the method uses pyridine represented by formula I or a derivative thereof as a raw material to generate 2,2-dipyridine represented by formula II by performing dehydrogenative coupling under the action of a supported catalyst in the presence of additives; and ##STR00003## wherein R is H, C.sub.1-C.sub.2 alkyl, Cl, or Br.

2. The method for preparing 2,2-dipyridine and derivatives thereof according to claim 1, wherein a support of the supported catalyst is an Al.sub.2O.sub.3SiO.sub.2MgO composite support, and a supported metal is a mixture of at least two of nickel and manganese, lanthanum, or cerium.

3. The method for preparing 2,2-dipyridine and derivatives thereof according to claim 2, wherein in the Al.sub.2O.sub.3SiO.sub.2MgO composite support, a content of SiO.sub.2 is 2 to 5%, a content of MgO is 2 to 5%, and the balance is Al.sub.2O.sub.3; and a supported amount of nickel does not exceed 20%, and is preferably 5 to 20%, a supported amount of manganese does not exceed 0.5%, a supported amount of lanthanum does not exceed 0.5%, and a supported amount of cerium does not exceed 0.5%.

4. The method for preparing 2,2-dipyridine and derivatives thereof according to claim 2, wherein a specific surface area of the Al.sub.2O.sub.3SiO.sub.2MgO composite support is greater than 120 m.sup.2/g, a pore volume is greater than 0.5 mL/g, a pore diameter 10 nm, and the pore diameter being 10 nm accounts for 60% of the pore volume.

5. The method for preparing 2,2-dipyridine and derivatives thereof according to claim 4, wherein the specific surface area of the Al.sub.2O.sub.3SiO.sub.2MgO composite support is 150 to 300 m.sup.2/g, the pore volume is 0.5 to 1.5 m.sup.2/g, the pore diameter is 10 to 20 nm, and the pore diameter of 10 to 20 nm accounts for at least 30% of the pore volume.

6. The method for preparing 2,2-dipyridine and derivatives thereof according to claim 1, wherein the additives are C.sub.1-C.sub.5straight chain alcohol or C.sub.1-C.sub.5 ester compounds, and consumption of the additives is 0.05 to 0.3% wt of pyridine or the derivative thereof.

7. The method for preparing 2,2-dipyridine and derivatives thereof according to claim 6, where in the C.sub.1-C.sub.5 straight chain alcohol compounds are methyl alcohol, ethyl alcohol, propyl alcohol, butyl alcohol, or amyl alcohol, and the C.sub.1-C.sub.5 ester compounds are methyl formate, methyl acetate, and ethyl acetate.

8. The method for preparing 2,2-dipyridine and derivatives thereof according to claim 1, wherein a total liquid phase flow rate of the raw material and the additives is 0.025 to 0.3 mL/g catalyst/min.

9. The method for preparing 2,2-dipyridine and derivatives thereof according to claim 8, wherein the total liquid phase flow rate of the raw material and the additives is 0.028 to 0.3 mL/g catalyst/min.

10. The method for preparing 2,2-dipyridine and derivatives thereof according to claim 1, wherein a temperature of a coupling reaction is 150 to 400 C., preferably 180 to 300 C., and a pressure of the coupling reaction is 0.55 to 2.4 Mpa.

Description

DETAILED DESCRIPTION

Embodiment 1: Preparation of Catalyst Support

[0019] A catalyst support was prepared by a pH swing method. The method was from articles of T. Ono, etc. (T. Ono, et., Studies in Surface Science and Catalysis, Vol. 16, 1983, 631-641).

[0020] A solution I was prepared: 1125 g of Al(NO.sub.3).sub.3 9.H.sub.2O was taken and dissolved into 1705 g of distilled water, and pH=2.2.

[0021] A solution II was prepared: 70 g of NaOH was taken and dissolved into 118 g of distilled water to prepare an NaOH water solution. 85 g of Al(OH).sub.3 was added to prepare an NaAlO.sub.2solution through stirring for more than 1 h. The solution was heated to 90 C. and stirred for more than 2 h. Then, a proper amount of distilled water was added to reach a total mass of the solution of 278 g, and the solution pH=10.

[0022] The solution I and the solution II were respectively poured into two funnels, and the funnels were connected onto a four-neck flask with stirring. 700 g of distilled water was contained in the four-neck flask, and was heated to 75 C. by ethylene glycol. The solution I was dripped into the four-neck flask. When the pH in the four-neck flask=3, the solution II was slowly dripped (the dripping time exceeded 5 min). When the pH in the four-neck flask=9, dripping of the solution II was stopped. After stirring for 5 min, a second round of dripping of the solution I was started, so that the pH=3. Then, the solution II was dripped, so that the pH=9.4 rounds were repeated in such a way. Before a 5th round was started, a certain amount of Mg(NO.sub.3).sub.2.6H.sub.2O was added into the solution I, a certain amount of Na.sub.4SiO.sub.4 was added into the solution II, and other steps were identical to those in the previous 4 rounds. After being filtered, obtained alumina hydrogel was washed by distilled water until a content of Na in filtrate was 0.03% lower than a content of Al in filter cake. The filter cake was made into clover-shaped extruded rubber with length of 2.5 to mm and a diameter of 0 to 1.5 mm, and the extruded rubber was put into a drying oven to be dried for more than 4 h at 120 C., and was roasted for more than 3 h in a muffle furnace at 500 C. to prepare the Al.sub.2O.sub.3SiO.sub.2MgO composite support.

[0023] Amounts of added Mg(NO.sub.3).sub.2.6H.sub.2O and Na.sub.4SiO.sub.4 are as shown in Table 1.

TABLE-US-00001 TABLE 1 Content of Magnesium Oxide and Silicon Dioxidein Support Consumption of Content of Content of Content Support magnesium nitrate magnesium sodium of silicon number hexahydrate (g) oxide (%) silicate (g) dioxide (%) a 1.03 2 0.49 2 b 2.72 5 1.04 4 c 1.58 3 0.76 3 d 1.60 3 1.02 4 e 1.07 2 1.27 5

[0024] Characterization parameters of the prepared support are as shown in Table 2:

TABLE-US-00002 TABLE 2 Characterization of Support Specific Pore Pore diameter distributed in pore volume Support surface volume 2 nm pore 10 nm pore 20 nm < pore number area(m.sup.2/g) (mL/g) diameter < 10 nm diameter 20 nm diameter 100 nm a 221 0.68 0.12 0.22 0.23 b 272 1.12 0.09 0.62 0.32 c 253 0.98 0.15 0.71 0.11 d 268 1.09 0.21 0.54 0.15 e 291 1.32 0.12 0.94 0.09

Embodiment 2: Preparation of Supported Catalyst

[0025] A support was selected and used as a catalyst support. A proper amount of Ni(NO.sub.3).sub.2.6H.sub.2O was weighed to be prepared into 150 g of a water solution with a certain concentration with water. 100 g of the support was impregnated in the water solution for 24 h, filtered, put into a drying box to be dried for 5 h under the conditions of 120 C. and 50 kpa. An obtained dry solid was roasted for 5 h at 400 C. to obtain a primarily impregnated catalyst solid. The catalyst solid was impregnated for 24 h in 100 g of a water solution of a mixture of Ni(NO.sub.3).sub.2, Ce(NO.sub.3).sub.3, La(NO.sub.3).sub.3, and Mn(NO.sub.3).sub.2 with a certain concentration, the subsequent drying and roasting conditions were identical to those of the first time, and a secondarily impregnated catalyst solid was obtained. The addition amount of supported metal salts is as shown in Table 3.

[0026] The secondarily impregnated catalyst solid was reduced: the prepared secondarily impregnated catalyst solid was taken and was charged into a stainless steel pipe with an inner diameter of 19 mm and a length of 600 mm, and a design pressure of the stainless steel pipe was 2.5 Mpa. Mixed gas of nitrogen gas and hydrogen gas was introduced from an upper part of the stainless steel pipe at a gas speed of 10 L/h. A content of the nitrogen gas was 99%, and a content of the hydrogen gas was 1%. The stainless steel pipe was covered with an electric heating jacket for heating. A temperature was raised to 450 C. from the room temperature at a speed of 1 C./min, and heat insulation was performed for 5 h at 450 C. Within first 2 h of heat insulation, the content of the hydrogen gas was uniformly increased to 99% from 1%, and the content of the nitrogen gas was uniformly reduced to 1% from 99%. After heat insulation for 5 h, heating was stopped. Gas introduction was stopped after a temperature of a catalyst bed layer was reduced to the room temperature, and the supported catalyst was obtained.

TABLE-US-00003 TABLE 3 Addition Amount of Supported Metal Salts of Catalyst and Supported Amount of Metal in Supported Catalyst Primary impregnation Secondary impregnation Addition Addition Addition Addition Addition Supported Supported Supported Supported amount of amount of amount of amount of amount of amount of amount of amount of amount of Catalyst nickel nickel cerium manganese lanthanum nickel cerium manganese lanthanum number salt* (g) salt (g) salt* (g) salt* (g) salt* (g) (%) (%) (%) (%) A 5.18 2.22 0.093 0.783 0.093 5 0.1 0.5 0.1 B 10.36 4.44 0.626 0.467 10 0.4 0.5 C 10.36 4.44 0.093 0.626 10 0.1 0.4 D 10.36 4.44 0.186 0.783 0.187 10 0.2 0.5 0.2 E 10.36 4.44 0.093 0.470 0.187 10 0.1 0.3 0.2 F 15.54 6.66 0.313 0.280 15 0.2 0.3 G 15.54 6.66 0.186 0.157 15 0.2 0.1 H 15.54 6.66 0.279 0.470 0.187 15 0.3 0.3 0.2 I 20.72 8.88 0.783 0.093 20 0.5 0.1 J 20.72 8.88 0.186 0.783 20 0.2 0.5 K 20.72 8.88 0.093 0.187 20 0.1 0.2 L 20.72 8.88 0.186 0.470 0.093 20 0.2 0.3 0.1 M 20.72 8.88 0.465 0.157 0.374 20 0.5 0.1 0.4 N 20.72 8.88 0.372 0.626 0.374 20 0.4 0.4 0.4 O 20.72 8.88 0.093 0.626 0.093 20 0.1 0.4 0.1 *Note: the nickel salt is Ni(NO.sub.3).sub.26H.sub.2O. The cerium salt is Ce(NO.sub.3).sub.36H.sub.2O. The manganese salt is Mn(NO.sub.3).sub.26H.sub.2O. The lanthanum salt is La(NO.sub.3).sub.36H.sub.2O.

Embodiment 3

[0027] 35 g of the supported catalyst prepared in Embodiment 2 was taken, and charged into a stainless steel pipe with an inner diameter of 19 mm and a length of 600 mm, and a design pressure of the stainless steel pipe was 2.5 Mpa.

[0028] With reference to parameters in Table 4, the stainless steel pipe was heated to raise the temperature to a reaction temperature. Pyridine or a pyridine derivative containing additives was pumped into the stainless steel pipe by a pump from the bottom of the stainless steel pipe at a certain flow rate. Reaction liquid flowed out from the top of the stainless steel pipe, and entered a 500 mL stainless steel gas-liquid separator to be received. The gas-liquid separator was provided with a back pressure valve and a pressure gauge. A cooling water jacket was disposed at the outside. Connection between the gas-liquid separator and a reactor were cut at intervals, a material in the gas-liquid separator was discharged, the pressure in the gas-liquid separator was supplemented to be identical to the pressure in the reactor, and then, the connection between the gas-liquid separator and the reactor was recovered for continuous reaction.

[0029] For a reaction system using pyridine as a raw material, a light-component mixture and a 2,2-dipyridine crude product were separated from discharged reaction liquid through distillation at 115 to 130 C. and a normal pressure, and pyridine and by-products of 2-methylpyridine were separated from the light-component mixture through rectification. The plate number of a rectification tower was 68.4. A tower kettle temperature was 135 C. A tower top temperature was 115 C. Are flux ratio was 2.7:1. The separated pyridine was reused.

[0030] For a reaction system using the pyridine derivative as a raw material, a light-component mixture and a 2,2-dipyridine derivative crude product were separated from discharged reaction liquid through distillation at 115 to 130 C. and 20 to 30 kpa, and the pyridine derivative was reused.

[0031] The 2,2-dipyridine crude product and the 2,2-dipyridine derivative crude product with a boiling point lower than 300 C. at a normal pressure were purified through rectification. A plate number of a rectification tower was 28.1. A pressure was 2.4 kpa. A tower kettle temperature was 190 C. A tower top temperature was 148 C. A reflux ratio was 0.3:1.

[0032] The 2,2-dipyridine derivative crude product with a boiling point higher than 300 C. at a normal pressure was recrystallized and purified by a solvent such as methyl alcohol and petroleum ether, that is, the crude product was dissolved into the solvent with the same weight, the temperature was raised to 40 C., after dissolution, the temperature was reduced to 5 C. for crystallization, a solid was filtered out, drying was performed, a 2,2-dipyridine derivative finished product was obtained, and crystallization mother liquid was reused.

[0033] Reaction results are as shown in Table 4:

TABLE-US-00004 TABLE 4 Catalyst Reaction Evaluation Liquid Service Consumption phase Reaction Reaction Product (g/g catalyst) life of Catalyst of additive flow rate temperature pressure 2,2- By- catalyst number Raw material Additive (% wt) (mL/min) ( C.) (Mpa) dipyridine product* (h) A Pyridine Methyl 0.05 1 180 0.55 825 28 1031 alcohol B Pyridine Methyl 0.15 2 180 0.55 1216 41 1501 alcohol C Pyridine Ethyl 0.3 5 180 0.55 1609 54 1962 alcohol D Pyridine Ethyl 0.2 8 180 0.55 2013 67 2548 alcohol E Pyridine N-propyl 0.05 10 180 0.55 2506 84 3133 alcohol F Pyridine N-butyl 0.15 10 200 0.75 2851 95 3564 alcohol G Pyridine Ethyl 0.15 10 200 0.75 2643 88 3388 acetate H Pyridine Methyl 0.15 8 200 0.75 2412 80 3015 acetate I Pyridine Methyl 0.15 8 200 0.75 2496 83 3120 formate J Pyridine Methyl 0.2 4 200 0.75 1523 51 1857 alcohol K Pyridine Methyl 0.2 4 220 1.05 1595 53 1994 alcohol L Pyridine N-amyl 0.2 6 220 1.05 1834 61 2293 alcohol M Pyridine N-amyl 0.2 6 220 1.05 1821 61 2248 alcohol N Pyridine Ethyl 0.15 10 220 1.05 2744 91 3430 acetate O Pyridine Ethyl 0.15 10 220 1.05 2633 88 3291 acetate O Pyridine 10 220 1.05 30 6 268 O 4-methylpyridine Ethyl 0.3 5 250 0.95 596 745 acetate O 4-methylpyridine 5 250 0.95 10 102 O 4-ethylpyridine Ethyl 0.3 5 300 1.64 493 624 acetate O 4-ethylpyridine 5 300 1.64 2 63 O 2-ethylpyridine Ethyl 0.3 5 300 2.26 565 706 acetate O 2-ethylpyridine 5 300 2.26 1 41 O 3-ethylpyridine Ethyl 0.3 5 300 1.75 623 779 acetate O 3-ethylpyridine 5 300 1.75 1 47 O 2-chloropyridine Methyl 0.2 5 300 1.78 379 486 alcohol O 2-chloropyridine 5 300 1.78 1 39 O 2-bromopyridine Methyl 0.2 5 300 2.19 385 481 alcohol O 2-bromopyridine 5 300 2.19 0.8 29 O 3-chloropyridine Ethyl 0.2 5 300 2.38 412 515 alcohol O 3-chloropyridine 5 300 2.38 0.5 28 O 3-bromopyridine Ethyl 0.2 5 300 1.78 423 529 alcohol O 3-bromopyridine 5 300 1.78 0.6 21 Note: by using pyridine as a raw material, a by-product is 2-methylpyridine. By using 4-methylpyridine as a raw material, a product is 4,4-dimethyl-2,2-dipyridine. By using 4-ethylpyridineas a raw material, a product is 4,4-diethyl-2,2-dipyridine. By using 2-ethylpyridineas a raw material, a product is 6,6-diethyl-2,2-dipyridine. By using 3-ethylpyridineas a raw material, a product is 5,5-diethyl-2,2-dipyridine. By using 2-chloropyridine as a raw material, a product is 6,6-dichloro-2,2-dipyridine. By using 2-bromopyridineas a raw material, a product is 6,6-dibromo-2,2-dipyridine. By using 3-chloropyridine as a raw material, a product is 5,5-dichloro-2,2-dipyridine. By using 3-bromopyridineas a raw material, a product is 5,5-dibromo-2,2-dipyridine.

[0034] g/g catalyst refers to a yield of 2,2-dipyridine or a derivative thereof generated by per gram of catalyst in the service life period.