Patent ID: 12221415

EXAMPLE 1

2-chloro-5-trifluoromethylpyridine (90.8 g, 0.5 mol) and 15% WCl6/AC (WCl6supported on activated carbon, the load was 15 wt %, 12 g) were added into a 250 mL autoclave (Inconel alloy), after the kettle cover was installed, a nitrogen gas of 2 MPa was charged and the pressure was maintained for 2 h, a leakage detection was conducted to the reaction kettle, after the reaction kettle was confirmed to be gastight, it was placed into an ice ethanol bath for cooling, when the reaction kettle was cooled to 0° C., about 37.5 g of chlorine gas (0.5 mol) was charged into the reaction kettle from the reaction kettle gas phase tube, then the reaction kettle was placed into a heating jacket with a magnetic stirrer, under a stirring condition the reaction system was heated to 150° C., at this time the pressure of the reaction system was about 2.0 MPa, at this temperature continuously reacted for 20 h. After the reaction was finished, when the temperature of the reaction system dropped to room temperature, nitrogen gas was charged into the reaction kettle from a liquid phase tube and a replacement was conducted for 30 min (the tail gas being replaced out was introduced into a alkaline washing bottle for absorption, and neutralized), the reaction kettle was opened, the catalyst and the products were separated by filtration, and a 10 wt % of NaOH solution was added to the products for neutralization, extracted, and liquid separated, to obtain an oily product. The oily product obtained was dried on anhydrous sodium sulfate then weighed and the mass was 107.0 g, a qualitative analysis was conducted by GC-MS, and a quantitative analysis was conducted by gas chromatography internal standard method. The conversion of 2-chloro-5-trifluoromethylpyridine as well as the selectivity and the yield of the chlorination reaction product are seen in Table 1.

EXAMPLE 2

The reaction temperature in Example 1 dropped from 150° C. to 100° C., other reaction condition and product treatment method were same as Example 1. The mass of the finally obtained oily product after drying was 91.2 g. The conversion of 2-chloro-5-trifluoromethylpyridine as well as the selectivity and the yield of the chlorination reaction products are seen Table 1.

EXAMPLE 3

15% WCl6/AC (WCl6supported on activated carbon, the load was 15 wt %,12 g) in Example 1 was changed to 15% MoCl5/AC (MoCl5supported on activated carbon, the load was 15 wt %, 12 g), other reaction condition and product treatment method were same as Example 1. The mass of the finally obtained oily product after drying was 97.9 g. The conversion of 2-chloro-5-trifluoromethylpyridine as well as the selectivity and the yield of the chlorination reaction product are seen in Table 1.

EXAMPLE 4

15% WCl6/AC (WCl6supported on activated carbon, the load was 15 wt %, 12 g) in Example 1 was changed to 15% FeCl3/AC (FeCl3supported on activated carbon, the load was 15 wt %, 12 g), other reaction condition and the product treatment method were same as Example 1. The mass of the finally obtained oily product after drying was 107.2 g. The conversion of 2-chloro-5-trifluoromethylpyridine as well as the selectivity and the yield of the chlorination reaction product are seen Table 1.

EXAMPLE 5

15% WCl6/AC (WCl6supported on activated carbon, the load was 15 wt %, 12 g) in Example 1 was changed to 15% CuCl2/AC (CuCl2supported on activated carbon, the load was 15 wt %, 12 g), other reaction condition and the product treatment method were same as Example 1. The mass of the oily product finally obtained after drying was 100.9 g. The conversion of 2-chloro-5-trifluoromethylpyridineas well as the selectivity and the yield of the chlorination reaction products are seen in Table 1.

EXAMPLE 6

15% WCl6/AC (WCl6supported on activated carbon, the load was 5 wt %, 12 g) in Example 1 was changed to 15% CuCl/AC (CuCl2supported on activated carbon, the load was 15 wt %, 12 g), other reaction condition and the product treatment method were same as Example 1. The mass of the finally obtained oily product after drying was 98.1 g. The conversion of 2-chloro-5-trifluoromethylpyridine as well as the selectivity and the yield of the chlorination reaction products are seen in Table 1.

EXAMPLE 7

15% WCl6/AC (WCl6supported on activated carbon, the load was 15 wt %, 12 g) in Example 1 was changed to 15% ZnCl2/AC (ZnCl2supported on activated carbon, the load was 15 wt %, 12 g), other reaction condition and the product treatment method were same as Example 1. The mass of the finally obtained oily product after drying was 100.7 g. The conversion of 2-chloro-5-trifluoromethylpyridine as well as the selectivity and the yield of chlorination reaction product are seen in Table 1.

EXAMPLE 8

15% WCl6/AC (WCl6supported on activated carbon, the load was 15 wt %, 12 g) in Example 1 was changed to 15% AlCl3/AC (AlCl3supported on activated carbon, the load was 15 wt %, 12 g), other reaction condition and the product treatment method were same as Example 1. The mass of the finally obtained oily product after drying was 105.2 g. The conversion of 2-chloro-5-trifluoromethylpyridine as well as the selectivity and the yield of the chlorination reaction product are seen in Table 1.

EXAMPLE 9

15% WCl6/AC (WCl6supported on activated carbon, the load was 15 wt %, 12 g) in Example 1 was changed to 15 wt % NaY/AC (NaY zeolite molecular sieve supported on activated carbon, the load was 15 wt %, Si/Al of NaY=5.4,12 g), other reaction condition and the product treatment method were same as Example 1. The mass of finally obtained oily product after drying was 103.5 g. The conversion of 2-chloro-5-trifluoromethylpyridineas well as the selectivity and the yield of the chlorination reaction products are seen in Table 1.

EXAMPLE 10

15% WCl6/AC (WCl6supported on activated carbon, the load was 15 wt %, 12 g) in Example 1 was changed to 15% HPW/AC (phosphotungstic acid supported on activated carbon, the load was 15 wt %, 12 g), other reaction condition and the product treatment method were same as Example 1. The mass of the finally obtained oily product after drying was 106.8 g. The conversion of 2-chloro-5-trifluoromethylpyridine as well as the selectivity and the yield of the chlorination reaction product are seen in Table 1.

EXAMPLE 11

15% WCl6/AC (WCl6supported on activated carbon, the load was 15 wt %, 12 g) in Example 1 was changed to 15% HSiW/AC (silicotungstic acid supported on activated carbon, the load was 15 wt %, 12 g), other reaction condition and the product treatment method were same as Example 1. The mass of the finally obtained oily product after drying was 93.2 g. The conversion of 2-chloro-5-trifluoromethylpyridine as well as the selectivity and the yield of the chlorination reaction product are seen in Table 1.

EXAMPLE 12

15% WCl6/AC (WCl6supported on activated carbon, the load was 15 wt %, 12 g) in Example 1 was changed to 15% HPW/TiO2(phosphotungstic acid supported on TiO2, the load was 15 wt %, 12 g), other reaction condition and the product treatment method were same as Example 1. The mass of the finally obtained oily product after drying was 93.2 g. The conversion of 2-chloro-5-trifluoromethylpyridine as well as the selectivity and the yield of the chlorination reaction product are seen in Table 1.

EXAMPLE 13

The introducing amount of chlorine gas in Example 1 was increased from 35.5 g (0.5 mol) to 71.0 g (1.0 mol), other reaction condition and the product treatment method were same as Example 1. The mass of the finally obtained oily product after drying was 108.7 g. The conversion of 2-chloro-5-trifluoromethylpyridine as well as the selectivity and the yield of the chlorination reaction product are seen in Table 1.

Comparative Example 1

15% WCl6/AC (WCl6supported on activated carbon, the load was 15 wt %, 12 g) in Example 1 was changed to WCl6(non-supported, 1.8 g), other reaction conditions and the product treatment method were same as Example 1. The mass of finally obtained oily product after drying was 98.2 g. The conversion of 2-chloro-5-trifluoromethylpyridine as well as the selectivity and the yield of the chlorination reaction product are seen in Table 1. Compared to Example 1, it is known that when the active component was not supported on AC, not only the conversion of 2-chloro-5-trifluoromethylpyridine was decreased from 99.9% to 65.2%, but also the selectivity of the desired product 2,3-dichloro-5-trifluoromethylpyridine was significantly reduced from 92.1% to 65.7%. It is seen that supporting the metal chloride on a carrier with high specific surface area can significantly improve its catalytic performance.

Comparative Example 2

The reaction temperature in Example 1 was raised from 150° C. to 200° C., other reaction condition and the product treatment method were same as Example 1. The mass of the finally obtained oily product after drying was 109.5 g. The conversion of 2-chloro-5-trifluoromethylpyridine as well as the selectivity and the yield of chlorination reaction product are seen in Table 1.

TABLE 1conversionofselectivity %2,5-2,3,5-2,6,3-2,3,6,5-ExampleCTF %DCTFDCTFTCTFother199.992.14.61.22.1210.288.21.20.510.1340.590.33.01.35.4492.987.18.41.82.7556.282.70.64.911.8653.285.93.01.36.3765.590.41.61.66.5879.985.97.11.95.1955.388.65.20.72.41098.790.602.37.01139.994.900.94.21219.886.49.10.83.713100.091.23.22.53.1Comparative65.265.75.22.17.0Example 1Comparative100.060.210.323.06.5Example 2

EXAMPLE 14

The internal diameter of the heating furnace was 30 mm, and the height was 600 mm, the upper and lower two stages were respectively temperature controlled. The upper stage was the chlorofluorination reaction region, and the lower stage was the chlorination reaction region. The internal diameter of the reaction tube was 19 mm, the length was 700 mm, and the material was stainless steel, the catalyst loading heights in the upper and lower two-stage were all 140 mm, and ensuring that the catalyst beds in the upper and the lower two stages were respectively in a constant temperature zone of the upper and lower two-stage heating furnace. The chlorofluorination catalyst bed was composed of 55.5% MgF2-40.0% Co2O3-0.55% CeO2(55.5%, 40%, 0.5% are mole percentage of the metal atoms, they are the ratio of metal atom moles of each component to sum of moles of the metal atoms, the composition of the chlorofluorination catalyst was shown as the molar ratio of metal atoms, the same below) of catalyst. The catalyst was molded into a cylinder having a diameter of 3 mm and a height of 4 mm. The chlorination catalyst bed was composed of 1% Pd/activated carbon (1% being the mass ratio of metal palladium in the catalyst after calcination, the compositions of the supported chlorination catalyst are shown as the ratio of the mass of metal atom to the total mass of the catalyst, the same below) of catalyst, the catalyst was molded into a cylinder having a diameter of 3 mm and a height of 4 mm.

The chlorofluorination reaction region was heated to 235° C., and the chlorination reaction region was heated to 290° C. The feed rate of anhydrous hydrogen fluoride was controlled at 10.00 g/h (0.500 mol/h), the catalyst was activated by introducing HF for 3 h, then the 3-methylpyridine being vaporized by using nitrogen gas as the carrier gas and chlorine gas were introduced into the reaction tube. Wherein, the flowrate of 3-methylpyridine was controlled at 4.00 g/h (0.043 mol/h), the flowrate of chlorine gas was controlled at 7.7 L/h (0.344 mol/h), the flowrate of nitrogen gas was maintained at 12.0 L/h (0.536 mol/h). The molar feed ratio of the reactants was 3-methylpyridine:chlorine gas:hydrogen fluoride:nitrogen gas=1:8:11.6:12.5. The contact time of all starting reaction material with the chlorofluorination catalyst bed and the chlorination catalyst bed catalyst were all 4.5 s, and reacted for 8 h.

The tail gas leaving the reaction tube was introduced into water a washing tower and an alkaline washing tower for condensation. The oil layer obtained was separated then neutralized with aqueous ammonia, and a steam distillation was conducted to obtain an oily product. The oily product obtained was dried on anhydrous sodium sulfate then weighed and the mass was 63.04 g, a quantitative analysis was conducted by gas chromatography internal standard method, and the mass content of 2,5-CTF was 70.8%, and the reaction yield was 71.5% (calculated on basis of 3-MP, the same below).

EXAMPLE 15

the upper stage in the reaction tube in Example 1 was filled with 55.5% MgF2-40% ZnO-0.5% K2O catalyst, the catalyst was molded into a cylinder having a diameter of 3 mm and a height of 4 mm, the lower stage is filled with 2% Pd/activated carbon catalyst, the catalyst was molded into a cylinder having a diameter of 3 mm and a height of 4 mm.

The chlorofluorination reaction region was heated to 265° C., and the chlorination reaction region was heated to 320° C. The feed rate of anhydrous hydrogen fluoride was 10.00 g/h (0.500 mol/h), the catalyst was activated by introducing HF for 3 h, then 3-methylpyridine being vaporized by using nitrogen gas as the carrier gas and chlorine gas were introduced into the reaction tube. Wherein, the flowrate of 3-methylpyridine was controlled at 4.00 g/h (0.043 mol/h), the flowrate of chlorine gas was controlled at 7.7 L/h (0.344 mol/h), the flowrate of nitrogen gas was maintained at 12.0 L/h (0.536 mol/h). The molar feed ratio of the reactants was 3-methylpyridine:chlorine gas:hydrogen fluoride:nitrogen gas=1:8:11.6:12.5, the contact time of all starting reaction material with the chlorofluorination catalyst bed and the chlorination catalyst bed catalyst were all 4.5 s, and reacted for 8 h.

The treatment method of the tail gas leaving the reaction was same as Example 1. 64.35 g of oily product was obtained, and a gas chromatography analysis was conducted, the mass content of 2,5-CTF was 65.7%, and the reaction yield was 67.8%.

EXAMPLE 16

the upper stage in the reaction tube in Example 14 was filled with 77.0% MgF2-20.0% Bi2O3-2.0% Na2O catalyst, the catalyst was molded into a cylinder having a diameter of 3 mm and a height of 4 mm, the lower stage was filled with MgF2catalyst, the catalyst was molded into a cylinder having a diameter of 3 mm and a height of 4 mm.

The chlorofluorination reaction region was heated to 220° C., and the chlorination reaction region was heated to 280° C. The feed rate of anhydrous hydrogen fluoride was controlled at 10.00 g/h (0.500 mol/h), the catalyst was activated by introducing HF for 3 h, then 3-methylpyridine being vaporized by using nitrogen gas as the carrier gas and chlorine gas were introduced into the reaction tube. Wherein, the flowrate of 3-methylpyridine was controlled at 4.00 g/h (0.043 mol/h), the flowrate of chlorine gas was controlled at 7.7 L/h (0.344 mol/h), the flowrate of nitrogen gas was maintained at 12.0 L/h (0.536 mol/h). Molar feed ratio of the reactants was 3-methylpyridine:chlorine gas:hydrogen fluoride:nitrogen gas=1:8:11.6:12.5, the contact time of all starting reaction material with the chlorofluorination catalyst bed and chlorination catalyst bed catalyst were all 4.5 s, and reacted for 8 h.

The treatment method of the tail gas leaving the reaction tube was same as Example 14. 61.94 g of oily product was obtained, and gas chromatography analysis was conducted, the mass content of 2,5-CTF was 77.2%, and reaction yield was 76.7%.

EXAMPLE 17

the upper stage of the reaction tube in Example 14 was filled with 85.0% CrF3-10.0% CuO-5.0% La2O3catalyst, the catalyst was molded into a cylinder having a diameter of 3 mm and a height of 4 mm, the lower stage was filled with MgO catalyst, the catalyst was molded into a cylinder having a diameter of 3 mm and a height of 4 mm.

The chlorofluorination reaction region was heated to 235° C., and the chlorination reaction region was heated to 300° C. The feed rate of anhydrous hydrogen fluoride was controlled at 10.32 g/h (0.516 mol/h), the catalyst was activated by introducing HF for 3 h, then 3-methylpyridine and chlorine gas being vaporized by using nitrogen gas as the carrier gas and chlorine gas were introduced into the reaction tube. Wherein, the flowrate of 3-methylpyridine was controlled at 4.00 g/h (0.043 mol/h), the flowrate of chlorine gas was controlled at 8.7 L/h (0.387 mol/h), the flowrate of nitrogen gas was maintained at 12.0 L/h (0.536 mol/h). Molar feed ratio of the reactants was 3-methylpyridine:chlorine gas:hydrogen fluoride:nitrogen gas=1:9:12:12.5, the contact time of all starting reaction material with the chlorofluorination catalyst bed and chlorination catalyst bed catalyst were all 4.0 s, and reacted for 6 h.

The treatment method of the tail gas leaving the reaction tube was same as Example 1. 40.50 g of oily product was obtained, and a gas chromatography analysis was conducted, the mass content of 2,5-CTF was 69.7%, the reaction yield was 74.5%.

EXAMPLE 18-20

Except for the catalyst, all operation condition was same as Example 16. In Example 18, the upper stage in the reaction tube was filled with 90.0% CrF3-8.0% Fe2O3-2.0% La2O3catalyst, the lower stage was filled with BaCl2catalyst; in Example 19, the upper stage in the reaction tube was filled with 90.0% AlF3-8.0% NiO-2.0% BaO catalyst, the lower stage was filled with CaCl2catalyst; in Example 20, the upper stage in the reaction tube was filled with 90.0% CrF3-8.0% NiO-2.0% Na2O catalyst, the lower stage was filled with 1.5% Pd/activated carbon catalyst.

The reaction respectively obtained 64.30 g, 65.34 g, 64.80 g of oily products, and gas chromatography analysis were conduct, the mass content of 2,5-CTF were respectively 73.2%, 69.9%, 73.3%, the reaction yield were respectively 75.5%, 73.2%, 76.1%.

EXAMPLE 21

The internal diameter of the heating furnace was 35 mm, and the height was 500 mm, the upper and lower two stages were respectively temperature controlled. The lower stage was chlorofluorination reaction region, and the upper stage was chlorination reaction the region. The material of the reaction tube was Inconel alloy, the internal diameter of the reaction tube was 30 mm, the length was 600 mm. The lower stage of the reaction tube was filled with 60 mL of 85% AlF3-10% Mn2O3-5% BaO (mean diameter being 0.15 mm) chlorofluorination catalyst, the height of the static bed was 89 mm, the upper stage of the reaction tube was filled with 60 mL of 1% Pd/activated carbon (mean diameter being 0.15 mm) chlorination catalyst, the height of the static bed was 89 mm. Distribution plates were placed at bottom of the reactor and middle of the reactor, for distribution of the gas flow and isolation and support of the catalyst. After 1 h of fluidization with nitrogen gas at 235° C. HF was charged at a feed rate of 8.59 g/h (0.430 mol/h) for 4 h, fluorination was conduted to the catalyst. Then, 3-methylpyridine being vaporized by using nitrogen gas as the carrier gas and chlorine gas were introduced into the reaction tube. Wherein, the flowrate of 3-methylpyridine was controlled at 4.00 g/h (0.043 mol/h), the flowrate of chlorine gas was controlled at 5.77 L/h (0.258 mol/h), and the flowrate of nitrogen gas was maintained at 9.62 L/h (0.430 mol/h). The molar feed ratio of the reactants was 3-methylpyridine:chlorine gas:hydrogen fluoride:nitrogen gas=1:6:10:10, the contact time of all starting reaction materials with the chlorofluorination catalyst bed and the chlorination catalyst bed catalyst were all 5.5 s, and reacted for 24 h.

The tail gas leaving the reaction tube was introduced into the water washing tower and the alkaline washing tower for condensation. The oil layer obtained was separated then neutralized with aqueous ammonia, and a steam distillation was conducted to obtain an oily product. The oily product obtained was dried on anhydrous sodium sulfate then weighed and the mass was 166.49 g, a quantitative analysis was conducted by gas chromatography internal standard method, the mass content of 2,5-CTF was 67.3%, and the reaction yield was 73.9%.

EXAMPLE 22

Except that the catalyst was different, other condition was same as Example 21. The lower stage of the reaction tube was filled with 60 mL of 90% AlF3-9% ZnCl2-1% CaO (mean diameter being 0.15 mm) chlorofluorination catalyst, the upper stage was filled with 60 mL of 1% Pd/Al2O3(mean diameter being 0.15 mm) chlorination catalyst. The product treatment and the analysis method were same as Example 21, to obtain 158.90 g of an oily product, the mass content of 2,5-CTF was 68.8%, and the reaction yield was 72.1%.

EXAMPLE 23

A stainless steel tube with a reaction tube internal diameter of 25 mm and length of 800 mm was used as the fixed bed reactor, and HZSM-5 molecular sieve with a volumn of 40 mL and a particle size of 5-10 mesh and Si/Al ratio of 100 (which means that H+is the counter cation) was filled into middle of the fixed bed reactor, a reaction tube line was linked, and nitrogen gas was introduced for purge, the flowrate of nitrogen gas was 100 mL/min. The reaction furnace was heated up to 290° C. at a heating rate of 5° C./min, after the catalyst bed reached the reaction temperature nitrogen gas purge was stopped and changed to introduction of chlorine gas for purge, meanwhile 3-trifluoromethylpyridine was continuously introduced into the fixed bed reactor, to initiate the reaction. The molar ratio of the reaction raw material 3-trifluoromethylpyridine to chlorine gas was 1:2, the contact time of the reactants within the catalyst bed was 30.9 s. The reaction product was condensed by an ice water bath then collected in a collection bottle, to obtain an oily product. After the reaction was finished, water washing and alkaline washing and acid-removal were conducted to the oily product, then dried on anhydrous sodium sulfate and distillation was conducted, a qualitative analysis was conducted to the distillate by GC-MS, a quantitative analysis was conducted to the distillate composition by gas chromatography internal standard method.

After the quantitative analysis, the reaction results were: the conversion of 3-trifluoromethylpyridine was 98.7%, and the selectivity of 2-chloro-5-trifluoromethylpyridine was 93.8%.

EXAMPLE 24

Except for the catalyst, other condition was same as Example 23, the catalyst used was 5A molecular sieve.

After a quantitative analysis, the reaction results were: the conversion of 3-trifluoromethylpyridine was 89.2%, and the selectivity of 2-chloro-5-trifluoromethylpyridine was 89.0%.

EXAMPLE 25

Except for the catalyst, other condition was same as Example 23, the catalyst used was 13X molecular sieve.

After a quantitative analysis, the reaction results were: the conversion of 3-trifluoromethylpyridinecon was 91.5%, and the selectivity of 2-chloro-5-trifluoromethylpyridine was 88.3%.

EXAMPLE 26

Except for the catalyst, other condition was same as Example 23, the catalyst used was β molecular sieve.

After a quantitative analysis, the reaction results were: the conversion of 3-trifluoromethylpyridine was 92.3%, and the selectivity of 2-chloro-5-trifluoromethylpyridine was 89.2%.

EXAMPLE 27

Except for the reaction temperature, other condition was same as Example 23, the reaction temperature was 350° C.

After a quantitative analysis, the reaction results were: the conversion of 3-trifluoromethylpyridine was 99.9%, and the selectivity of 2-chloro-5-trifluoromethylpyridine was 87.1%.

EXAMPLE 28

The material of the reaction tube was Inconel alloy, the internal diameter of the reaction tube was 30 mm, the length was 400 mm. The reaction tube was filled with 60 mL of HZSM-5 molecular sieve catalyst with a mean diameter of 0.15 mm and a Si/Al ration of 100, after 1 h of fluidization with nitrogen gas at 235° C., it was heated up to 290° C. at a heating rate of 5° C./min, after the catalyst bed reached the reaction temperature the nitrogen gas purge was stopped and changed to introduction of chlorine gas for purge, meanwhile 3-trifluoromethylpyridine was continuously introduced into the fixed bed reactor, to initiate the reaction. The molar ratio of reaction raw material 3-trifluoromethylpyridine to chlorine gas was 1:2, and the contact time of the reactants within the catalyst bed was 58.5 s. The reaction product was condensed by an ice water bath then collected in a collection bottle, to obtain an oily matter. After the reaction was finished, water washing and alkaline washing and acid-removal were conducted against the oily matter, dried on anhydrous sodium sulfate then distillation was conducted, a qualitative analysis was conducted to the distillate by GC-MS, a quantitative analysis was conducted to the distillate composition by gas chromatography internal standard method.

After the quantitative analysis, the reaction results were: the version of 3-trifluoromethylpyridinecon was 97.9%, and the selectivity of 2-chloro-5-trifluoromethylpyridine was 94.5%.

EXAMPLE 29

Except for the catalyst, other condition were same as Example 28, the catalyst used was HZSM-5 molecular sieve with Si/Al=50.

After a quantitative analysis, the reaction results were: the conversion of 3-trifluoromethylpyridine was 99.0%, the selectivity of 2-chloro-5-trifluoromethylpyridine was 90.1%.

EXAMPLE 30

Except for the catalyst, other condition was same as Example 28, the catalyst used was NaZSM-5 (which means Na+is the counter cation) molecular sieve with Si/Al=100.

After a quantitative analysis, the reaction results were: the conversion of 3-trifluoromethylpyridine was 95.7%, and the selectivity of 2-chloro-5-trifluoromethylpyridine was 92.5%.

EXAMPLE 31

Except for the catalyst, other condition was same as Example 28, the catalyst used was Si/Al=100 of KZSM-5 (which means K+is the counter cation) molecular sieve.

After a quantitative analysis, the reaction results were: the conversion of 3-trifluoromethylpyridine was 92.3%, and the selectivity of 2-chloro-5-trifluoromethylpyridine was 92.0%.

EXAMPLE 32

Except for the catalyst, other condition was same as Example 28, the catalyst used was CaZSM-5 (which means Ca+is the counter cation) molecular sieve with a Si/Al=100.

After a quantitative analysis, the reaction result were: the conversion of 3-trifluoromethylpyridine was 4.4%, the selectivity of 2-chloro-5-trifluoromethylpyridine was 88.1%.

EXAMPLE 33

Except for the chlorine gas ratio, other condition was same as Example 23, the molar ratio of raw material 3-trifluoromethylpyridine to chlorine gas was 1:10.

After a quantitative analysis, the reaction results were: the conversion of 3-trifluoromethylpyridine was 98.5%, and the selectivity of 2-chloro-5-trifluoromethylpyridine was 85.2%.

Comparative Example 3

The catalyst in Example 23 was changed to a HZSM-5 molecular sieve with Si/Al of 22, other condition was unchanged.

After a quantitative analysis, the reaction results were: the conversion of 3-trifluoromethylpyridine was 99.9%, but the selectivity of the desired product 2-chloro-5-trifluoromethylpyridine was only 47.3%.

Comparative Example 4

According to the disclosure in China CN104610137 a FeCl3/activated carbon catalyst was used as the catalyst, and the reaction temperature was controlled at 250° C., other operation condition was consistent with Example 23.

After a quantitative analysis, the reaction results were: the conversion of 3-trifluoromethylpyridine was 96.2%, the selectivity of the desired product 2-chloro-5-trifluoromethylpyridine was only 20.2%.

EXAMPLE 34

The internal diameter of the heating furnace was 30 mm, and the height was 600 mm. The internal diameter of the reaction tube was 19 mm, and the length was 700 mm, the material was stainless steel, the loading height of the catalyst was 140 mm. The catalyst bed was composed of 1% Pd/activated carbon (1% being the mass ratio of metal palladium in the catalyst after calcination, the composition of the supported chlorination catalyst are all shown as the ratio of mass of metal atom to total mass of the catalyst, the same below) catalyst, the catalyst was molded into a cylinder having a diameter of 3 mm and a height of 4 mm. The reaction region was heated to 290° C., the vaporized 3-trifluoromethylpyridine and chlorine gas were introduced into the reaction tube. Wherein, the flowrate of 3-trifluoromethylpyridine was controlled at 6.33 g/h (0.043 mol/h), the flowrate of chlorine gas was controlled at 7.7 L/h (0.344 mol/h). Molar feed ratio of the reactants was 3-trifluoromethylpyridine:chlorine gas=1:8, the contact time of all starting reaction material with the catalyst bed were 16.5 s, and reacted for 8 h.

The tail gas leaving the reaction tube was introduced into the water washing tower and the alkaline washing tower for condensation. The oil layer obtained was separated then neutralized with aqueous ammonia, and a steam distillation was conducted to obtain an oily product. The oily product obtained was dried on anhydrous sodium sulfate then weighed and the mass was 66.28 g, a quantitative analysis was conducted by gas chromatography internal standard method, the mass content of 2-chloro-5-trifluoromethylpyridine was 88.7%, and the yield was 94.1% (calculated relative to 3-trifluoromethylpyridine, the same below).

EXAMPLE 35

the reaction tube in Example 34 was filled with 2% Pd/activated carbon catalyst, the catalyst was molded into a cylinder having a diameter of 3 mm and a height of 4 mm. The reaction region was heated to 320° C. The vaporized 3-trifluoromethylpyridine and chlorine gas were introduced into the reaction tube. Wherein, the flowrate of 3-trifluoromethylpyridine was controlled at 6.33 g/h (0.043 mol/h), the flowrate of chlorine gas was controlled at 7.7 L/h (0.344 mol/h). Molar feed ratio of the reactants was 3-trifluoromethylpyridine:chlorine gas=1:8, the contact time of all starting reaction materials with the catalyst bed were 16.5 s, and reacted for 8 h.

The treatment method of the tail gas leaving the reaction tube was same as Example 34, to obtain 67.59 g of an oily product, and a gas chromatography analysis was conducted, the mass content of 2-chloro-5-trifluoromethylpyridine was 84.8%, and the yield was 91.7%.

EXAMPLE 36

the reaction tube in Example 34 was filled with MgF2catalyst, the catalyst was molded into a cylinder having a diameter of 3 mm and a height of 4 mm. The reaction region was heated to 280° C. The vaporized 3-trifluoromethylpyridine and chlorine gas were introduced into the reaction tube. Wherein, the flowrate of 3-trifluoromethylpyridine was controlled at 6.33 g/h (0.043 mol/h), the flowrate of chlorine gas was controlled at 7.7 L/h (0.344 mol/h). Molar feed ratio of the reactants was 3-trifluoromethylpyridine:chlorine gas=1:8, the contact time of all starting reaction material with the catalyst bed were 16.5 s, and reacted for 8 h.

The treatment method of the tail gas leaving the reaction tube was same as Example 34, to obtain 65.86 g of an oily product, and a gas chromatography analysis was conduct, the mass content of 2-chloro-5-trifluoromethylpyridineof was 87.8%, and the yield was 92.5%.

EXAMPLE 37

the reaction tube in Example 34 was filled with a MgO catalyst, the catalyst was molded into a cylinder having a diameter of 3 mm and a height of 4 mm. The reaction region was heated to 300° C. The vaporized 3-trifluoromethylpyridine and chlorine gas were introduced into the reaction tube. Wherein, the flowrate of 3-trifluoromethylpyridine was controlled at 6.33 g/h (0.043 mol/h), the flowrate of chlorine gas was controlled at 8.7 L/h (0.387 mol/h). Molar feed ratio of the reactants was 3-trifluoromethylpyridine=1:9, the contact time of all starting reaction material with the catalyst bed were 14.8 s, and reacted for 6 h.

The treatment method of the tail gas leaving the reaction tube was same as Example 34. 48.49 g of an oily product was obtained, and a gas chromatography analysis was conducted, the mass content of 2-chloro-5-trifluoromethylpyridine was 86.7%, and the yield was 89.6%.

EXAMPLE 38-40

Except for the catalyst, all operation condition was same as Example 35. In Example 38, the reaction tube was filled with BaCl2catalyst; in Example 39, the reaction tube was filled with CaCl12catalyst; in Example 40, the reaction tube was filled with 1.5% Pd/activated carbon catalyst. The reaction respectively obtained 66.25 g, 61.49 g, 64.57 g of oily products, and gas chromatography analysis were conducted, the mass content of 2-chloro-5-trifluoromethylpyridine were respectively 85.0%, 89.5%, 89.8%, and the yield were respectively 90.1%, 88.0%, 92.8%.

EXAMPLE 41

Internal diameter of the heating furnace was 35 mm, the height was 500 mm. The material of the reaction tube was Inconel alloy, the internal diameter of the reaction tube was 30 mm, and the length was 600 mm. The reaction tube was filled with 60 mL of 1% Pd/activated carbon (mean diameter being 0.15 mm) chlorination catalyst, the height of the static bed was 89 mm. After 1 h of fluidization with nitrogen gas at 235° C., the vaporized 3-trifluoromethylpyridine and chlorine gas were introduced into the reaction tube. Wherein, the flowrate of 3-trifluoromethylpyridine was controlled at 6.33 g/h (0.043 mol/h), the flowrate of chlorine gas was controlled at 5.77 L/h (0.258 mol/h), the flowrate of nitrogen gas was maintained at 9.62 L/h (0.430 mol/h). Molar feed ratio of the reactants was 3-trifluoromethylpyridine:chlorine gas=1:6, the contact time of all starting reaction materials with the catalyst bed was 13.5s, and reacted for 24 h.

The tail gas leaving the reaction tube was introduced into the water washing tower and the alkaline washing tower for condensation. The oil layer obtained was separated then neutralized with aqueous ammonia, and a steam distillation was conducted against the oily product obtained. The oily product obtained was dried on anhydrous sodium sulfate then weighed and the mass was 185.88 g, a quantitative analysis was conducted by gas chromatography internal standard method, the mass content of 2-chloro-5-trifluoromethylpyridine was 95.8%, and the yield was 94.9%.

EXAMPLE 42

Except that catalyst was different, other condition was same as Example 41. The reaction tube was filled with 60 mL of 1% Pd/Al2O3(mean diameter being 0.15 mm) chlorination catalyst. The product treatment and analysis method were same as Example 38, to obtain 179.69 g of an oily product, by chromatography analysis the mass content of 2-chloro-5-trifluoromethylpyridine was 94.6%, and the yield was 90.7%.

The above preparing method of 2,3-dichloro-5-trifluoromethylpyridine provided by the present invention significantly increases the yield and the selectivity of the desired product 2,3-dichloro-5-trifluoromethylpyridine. The selectivity of 2,3-dichloro-5-trifluoromethylpyridine can substantially reach at least 82% or more. The method provided by the present invention not only reduces the unit consumption of the product, and reduces separation cost, but also the reaction temperature is much lower than 400° C., the method can significantly reduce energy consumption and improve safety.