Preparation method of catalyst for synthesizing 3-methylpyridine from acrolein, propionaldehyde and ammonia

Abstract

The invention provides a method for preparing a cocrystallized zeolite catalyst for synthesizing 3-methylpyridine from acrolein, propionaldehyde and ammonia. The catalyst contains 35-50 wt% of ZSM11 / BEA hydrogen-type cocrystallized zeolite, 0.5-3.0 wt% of boron, and the remainder is aluminum oxide and kaolin. The ZSM11 / BEA hydrogen-type eutectic zeolite, boric acid, aluminum oxide, kaolin and water are uniformly mixed, the solid / water weight ratio in the mixture is 0.2-0.5, spray molding and roasting are carried out to prepare the catalyst of the invention. The invention has the advantages of being suitable for industrial operation, relatively simple process, high yield of 3-methylpyridine and pyridine base, and the like.

Description

Technical Field

[0001] The invention belongs to the field of chemical industry, and particularly relates to a co-crystallized zeolite catalyst for synthesizing 3-methylpyridine from acrolein, propionaldehyde and ammonia and a preparation method thereof. Background Art

[0002] 3-Methylpyridine is the main raw material for the preparation of nicotinic acid and nicotinic acid ammonia. It can also be used to prepare vitamins. It is also an important intermediate for the synthesis of pyridine flavors and new pesticides. Currently, it is in short supply. 3-Methylpyridine was first recovered from coal coking fractionation byproducts, but due to the large number of pyridine components in the coking byproducts, the complex products, the difficulty of separation, and the low yield, it is currently mainly produced by the aldehyde ammonia synthesis method.

[0003] At present, the method for synthesizing 3-picoline is mainly based on the synthesis of 2-picoline and 4-picoline by acetaldehyde and ammonia gas phase method, and a large amount of formaldehyde is added to the raw materials to prepare pyridine and 3-picoline. Because the method is mature and the process operation is simple, the industrial preparation of 3-picoline currently adopts this method.

[0004] British patents GB1346630, GB790994 and USP3946020, USP4675410, USP4810794, USP4089863, and USP5395940 all reported this. US3946020 reported that on H-SiO2-Al2O3 catalyst, formaldehyde / acetaldehyde / ammonia = 12 / 12 / 26.4, about 420℃, and the space velocity was 1160h -1 Under the above conditions, the yield of pyridine was 38.1% and that of 3-methylpyridine was 25.9%. Chinese patents CN1506353A, CN1506354 A, and CN 1566093A also reported the method of synthesizing pyridine and 3-methylpyridine by formaldehyde acetaldehyde method. CN1566093A reported the use of formaldehyde / acetaldehyde / ammonia = 1 / 2 / 4.5, with Co-Pb-ZSM5 as catalyst, at about 450°C and a space velocity of 1000h -1 Under the conditions, the pyridine alkali yield was 83%, wherein the pyridine yield was 68%, 2-picoline was 4%, 3-picoline was 4.5%, and 4-picoline was 6.5%. When formaldehyde / acetaldehyde / ammonia=1 / 1 / 4.5, the pyridine alkali yield was 81.5%, wherein, the pyridine yield was 56%, and the 3-picoline yield reached 24.5%, and 2-picoline and 4-picoline were not produced substantially. As can be seen, by increasing the amount of formaldehyde, the yield of 3-picoline can be improved, but the generation of 4-picoline is difficult to avoid completely. As is well known, 3-picoline and 4-picoline are difficult to separate, so it is difficult to obtain high-purity 3-picoline.

[0005] In order to avoid the generation of 4-picoline as far as possible, it is necessary to avoid using acetaldehyde in the raw materials. Therefore, a large number of studies have been conducted using acrolein as a raw material to prepare 3-picoline. British patents GB1020857, GB1187347, GB1208291, and GB1222971 have reported methods for synthesizing pyridine and 3-picoline in the gas phase using acrolein and ammonia, and the product does not contain 4-picoline. Among them, GB1020857 reported the use of acrolein / ammonia / water = 1 / 5 / 1, with BP / SiO2-Al2O3 as catalyst, temperature of about 350°C, contact time of 5 seconds, and obtained a pyridine base yield of 60%, wherein the pyridine yield was 25%, and the 3-picoline yield was 35%. GB1187347 reports that 3% acrolein, 6% ammonia, 3% oxygen, 40% water vapor and 48% nitrogen are used as raw materials, F / Al2O3-SiO2 is a catalyst, the temperature is about 400°C, and the contact time is 2 seconds, and a pyridine base yield of about 76.8% is obtained, wherein pyridine is 61.9% and 3-picoline is 14.9%. USP3960766, 3917542, 3898177 report that F-Al2O3 is used as a carrier, and acrolein and ammonia react to prepare pyridine and 3-picoline. Among them, USP3898177 reports that acrolein / ammonia / nitrogen=1 / 2 / 2.7 is used, and a pyridine base yield of about 71% is obtained at 400°C-420°C gas phase reaction, wherein the pyridine yield is 26.6% and the 3-picoline yield is 44%.

[0006] Since a large amount of pyridine is generated by the gas phase reaction of acrolein and ammonia to generate 3-methylpyridine, it should be produced by the high temperature cracking of acrolein or the cracking and demethylation of 3-methylpyridine. At the same time, since acrolein is relatively active and easy to self-polymerize, some patents consider adding other organic substances to partially replace acrolein as a raw material. For example, acetaldehyde (British patents GB963887, GB1005984, GB1069368, USP4147874, 5952258), propylene oxide (British patent GB1192255), ketone (British patent GB920526, Canadian patent CAP1063121), propanol (USP896049), trimeraldehyde (British patent GB887688, USP4163854) are added. Among them, US5952258 reports the use of acrolein / acetaldehyde / ammonia=1 / 0.5 / 2, gas hourly space velocity 83h -1 The reaction temperature was 450°C, and a 78% pyridine base yield was obtained using HZSM-5 / In as the catalyst, including a 50% pyridine yield and a 27% 3-methylpyridine yield.

[0007] GB887688 uses acrolein and propionaldehyde to react, propionaldehyde / acrolein (molar ratio) = 1-1.2, ammonia / aldehyde (molar ratio) = 0.5-5, the reaction temperature is 375-475°C, and SiO2-Al2O3 is used as a catalyst to obtain a 3-methylpyridine conversion rate of about 50%, and the product pyridine base does not contain 4-methylpyridine.

[0008] USP4163854 reported that acrolein and propionaldehyde were used as raw materials for the reaction, and high specific surface area SiO2-Al2O3 was used as a catalyst, and the reaction was carried out at 400-460°C. When the raw materials of acrolein / propionaldehyde = 2 / 1 were used, 60.6% of 3-methylpyridine and 6.2% of pyridine yield were obtained. When the molar ratio of acrolein / propionaldehyde was changed between 3 / 2-4 / 1, the yields of pyridine and 3-methylpyridine did not change much, the yield of pyridine was maintained at 6%-10%, and the yield of 3-methylpyridine was maintained at about 60%.

[0009] USP5079367 prepared Cat-A, Cat-B and Cat-E catalysts (the ratio of molecular sieve to binder was 60:40 wt / wt), where Cat-A and Cat-E molecular sieves were borosilicate MFI molecular sieves, and Cat-B molecular sieve was silica-alumina MFI molecular sieve. -1 Under the conditions of acrolein: propionaldehyde: ammonia molar ratio = 1:1:3, aldehydes were completely converted on Cat-A, Cat-B and Cat-E catalysts, and the yields of 3-methylpyridine reached 87.2%, 89.3% and 91.0%, respectively.

[0010] CN10847947B discloses a method for preparing a fixed bed catalyst for synthesizing 3-methylpyridine from acrolein, propionaldehyde and ammonia, i.e., an integral FMgZSM-11 binder-free molecular sieve. This patent application is a method for preparing a fluidized bed catalyst for synthesizing 3-methylpyridine from acrolein, propionaldehyde and ammonia. For a fluidized bed catalyst, it not only needs to have high activity, but also must have certain anti-wear performance (generally wear coefficient <3wt%), so the molecular sieve generally needs to be mixed with kaolin and alumina, and sprayed into spheres and roasted to meet the above requirements.

[0011] ZSM11 / BEA co-crystallized zeolite is different from the mechanical mixture of ZSM11 and BEA. It is a mixture of ZSM11 crystal phase and BEA crystal phase interlaced and interwoven, and the specific structure needs further study. At present, there is no report on the use of this crystalline molecular sieve for the synthesis of 3-methylpyridine from acrolein, propionaldehyde and ammonia. Compared with the single ZSM11 or single BEA molecular sieve catalyst, the yield of 3-methylpyridine is higher. It may be that the synergistic effect of ZSM11 and BEA, the 3-methylpyridine synthesized by the ten-membered ring straight channel (ZSM11) quickly diffuses to the outside of the molecular sieve through the twelve-membered ring large channel (BEA), that is, the product diffusion coefficient is increased, thereby promoting the reaction. The relevant mechanism needs to be studied. Summary of the invention

[0012] The object of the present invention is to provide a method for preparing a co-crystallized zeolite catalyst for synthesizing 3-methylpyridine from acrolein, propionaldehyde and ammonia.

[0013] The invention provides a cocrystallized zeolite catalyst for synthesizing 3-methylpyridine from acrolein, propionaldehyde and ammonia. The catalyst contains 35-50 wt% ZSM11 / BEA hydrogen-type cocrystallized zeolite, 0.5-3.0 wt% boron (preferably 1.0-2.0 wt%), and the rest is alumina and kaolin.

[0014] The invention provides a co-crystallized zeolite catalyst for synthesizing 3-methylpyridine from acrolein, propionaldehyde and ammonia, wherein the weight ratio of ZSM11 to BEA in the ZSM11 / BEA hydrogen-type co-crystallized zeolite is 1.0-90.

[0015] The present invention provides a co-crystallized zeolite catalyst for synthesizing 3-methylpyridine from acrolein, propionaldehyde and ammonia. The aluminum oxide is derived from aluminum sol or aluminum chloride and its content is 20-40 weight percent; the kaolin content is 15-25 weight percent.

[0016] The present invention also provides a method for preparing a cocrystallized zeolite catalyst for synthesizing 3-methylpyridine from acrolein, propionaldehyde and ammonia. 35-50 wt% ZSM11 / BEA hydrogen-type cocrystallized zeolite, 0.5-3.0 wt% boron, 20-40 wt% alumina, 15-25 wt% kaolin and water are uniformly mixed, the solid / water weight ratio in the mixture is 0.2-0.5, and the mixture is spray-formed and dried to obtain the catalyst. Among them, the inlet temperature in the spraying conditions is 480-600°C, the tail gas temperature is 200-300°C, the spraying pressure is 6-10Mpa, the roasting temperature is 550-600°C, and the time is 2-5 hours.

[0017] The catalyst provided by the present invention is used to synthesize 3-methylpyridine from acrolein, propionaldehyde and ammonia. The reaction conditions are: 0.1MPa, 460°C, acrolein / propionaldehyde / ammonia molar ratio of 1 / 1 / 3, and the weight space velocity of aldehyde is 0.6h -1, N2 flow rate is 60ml / min; fluidized bed.

[0018] The invention has the advantages of being applicable to industrial operation, relatively simple process, high yield of 3-methylpyridine and pyridine base, and the like. DETAILED DESCRIPTION

[0019] The present invention will be further described in the following examples, but the present invention is not limited thereto.

[0020] Comparative Example 1

[0021] A certain amount of hydrogen-type ZSM11 zeolite, boric acid, aluminum sol, kaolin, and deionized water were uniformly mixed, sprayed, and dried to obtain catalyst A. The spray conditions included an inlet temperature of 600°C, an exhaust gas temperature of 200°C, a spray pressure of 5 MPa, a calcination temperature of 600°C, and a calcination time of 2 hours. The weight contents of ZSM11 zeolite, B, and alumina in the obtained catalyst A were 41%, 1.1%, and 30%, respectively.

[0022] Comparative Example 2

[0023] A certain amount of hydrogen-type BEA zeolite, boric acid, aluminum sol, kaolin, and deionized water were uniformly mixed, sprayed, and dried to obtain catalyst B. The spray conditions were as follows: the inlet temperature was 600°C, the tail gas temperature was 200°C, the spray pressure was 9 MPa, the calcination temperature was 600°C, and the time was 2 hours. The weight contents of BEA zeolite, B, and alumina in the obtained catalyst B were 41%, 1.1%, and 30%, respectively.

[0024] Example 1

[0025] A certain amount of 80 wt% ZSM11 / 20 wt% BEA hydrogen co-crystallized zeolite, boric acid, aluminum sol, kaolin, and deionized water were uniformly mixed, sprayed, and dried to obtain catalyst C. The spray conditions included an inlet temperature of 600°C, an exhaust gas temperature of 200°C, a spray pressure of 6 MPa, a calcination temperature of 600°C, and a calcination time of 2 hours. The weight contents of catalyst C in the obtained catalyst C were 80 wt% ZSM11 / 20 wt% BEA hydrogen co-crystallized zeolite, B, and alumina, respectively, which were 41%, 1.1%, and 30%.

[0026] Example 2

[0027] A certain amount of 90 wt% ZSM11 / 10 wt% BEA hydrogen co-crystallized zeolite, boric acid, aluminum sol, kaolin, and deionized water were uniformly mixed and sprayed to form, and then dried to obtain catalyst D. The spray conditions included an inlet temperature of 480°C, an exhaust gas temperature of 260°C, a spray pressure of 10 MPa, a calcination temperature of 550°C, and 5 hours. The obtained catalyst D contained 90 wt% ZSM11 / 10 wt% BEA hydrogen co-crystallized zeolite, B, and alumina in weight contents of 35%, 0.5%, and 35%, respectively.

[0028] Example 3

[0029] A certain amount of 50 wt% ZSM11 / 50 wt% BEA hydrogen co-crystallized zeolite, boric acid, aluminum sol, kaolin, and deionized water were uniformly mixed, sprayed, and dried to obtain catalyst E. The spray conditions included an inlet temperature of 500°C, an exhaust gas temperature of 250°C, a spray pressure of 8 MPa, a calcination temperature of 580°C, and a calcination time of 3 hours. The obtained catalyst E contained 50 wt% ZSM11 / 50 wt% BEA hydrogen co-crystallized zeolite, B, and alumina in weight contents of 50%, 3.0%, and 20%, respectively.

[0030] Example 4

[0031] A certain amount of 70 wt% ZSM11 / 30 wt% BEA hydrogen co-crystallized zeolite, boric acid, aluminum sol, kaolin, and deionized water were uniformly mixed, sprayed, and dried to obtain catalyst F. The spray conditions included an inlet temperature of 520°C, an exhaust gas temperature of 230°C, a spray pressure of 7.0 MPa, a calcination temperature of 600°C, and a calcination time of 1.5 hours. The obtained catalyst F contained 70 wt% ZSM11 / 30 wt% BEA hydrogen co-crystallized zeolite, B, and alumina in weight contents of 37%, 2.0%, and 28%, respectively.

[0032] Example 5

[0033] A certain amount of 60 wt% ZSM11 / 40 wt% BEA hydrogen co-crystallized zeolite, boric acid, aluminum chloride, kaolin, and deionized water were uniformly mixed, sprayed, and dried to obtain catalyst G. The spray conditions included an inlet temperature of 500°C, an exhaust gas temperature of 210°C, a spray pressure of 8 MPa, a calcination temperature of 550°C, and a calcination time of 3 hours. The obtained catalyst G contained 60 wt% ZSM11 / 40 wt% BEA hydrogen co-crystallized zeolite, B, and alumina in weight contents of 39%, 2.5%, and 40%, respectively.

[0034] Comparative Examples 1 to 2 and Examples 1 to 5 Reaction Evaluation:

[0035] The comparative examples and embodiments of the present invention are applied to the synthesis of 3-methylpyridine from acrolein, propionaldehyde and ammonia. 20g of catalyst is placed in a fixed fluidized bed reaction tube, the temperature is raised to the reaction temperature under N2 and ammonia atmosphere, and the reaction is carried out under the conditions shown in Table 1. The raw materials are a mixture of acrolein, propionaldehyde and ammonia, which pass through the catalyst bed from bottom to top, and a gas phase condensation reaction occurs at a certain space velocity and temperature to generate the target product 3-methylpyridine and pyridine base, etc. The reaction lasts 240 minutes each time, the reactor outlet is connected to a condenser, the outlet is connected to a receiving bottle, and the tail gas is washed and absorbed with two-stage water. The concentration of pyridine base is analyzed by gas chromatography internal standard method.

[0036] From the results in Table 1, it can be seen that the yield of 3-methylpyridine and the total pyridine base yield of ZSM11 (catalyst A) and BEA (catalyst B) alone are lower than those of the catalysts of the present invention. The catalysts C to F provided by the present invention are similar in general, with a weight yield of about 50% for the generated 3-methylpyridine, a total pyridine base yield of about 70%, and a 3-methylpyridine / pyridine molar ratio greater than 6.

[0037] Table 1 Evaluation results of catalysts for the reaction of acrolein, propionaldehyde and ammonia to produce 3-methylpyridine

[0038]

[0039] Reaction conditions: temperature 460°C; molar ratio of acrolein / propionaldehyde / ammonia 1 / 1 / 3; weight space velocity of aldehyde 0.6h -1 ; N2 flow rate is 60ml / min; fluidized bed, catalyst 20g.

Claims

1. A co-crystallized zeolite catalyst for synthesizing 3-methylpyridine from acrolein, propionaldehyde and ammonia, characterized in that: The catalyst contains 35-50 wt% ZSM11 / BEA hydrogen-type co-crystallized zeolite, 0.5-3.0 wt% boron, and the rest is aluminum oxide and kaolin; the aluminum oxide is derived from aluminum sol or aluminum chloride and its content is 20-40 wt%; the kaolin content is 15-35 wt%.

2. The co-crystallized zeolite catalyst for synthesizing 3-methylpyridine from acrolein, propionaldehyde and ammonia according to claim 1, characterized in that: The weight ratio of ZSM11 to BEA in the ZSM11 / BEA hydrogen-type co-crystallized zeolite is 1.0-90.

3. The co-crystallized zeolite catalyst for synthesizing 3-methylpyridine from acrolein, propionaldehyde and ammonia according to claim 1, characterized in that: The boron content is 1.0-2.0 wt%.

4. A method for preparing the co-crystallized zeolite catalyst for synthesizing 3-methylpyridine from acrolein, propionaldehyde and ammonia as claimed in claim 1, characterized in that: 35-50 wt% hydrogen ZSM11 / BEA, 0.5-3.0 wt% B, 20-40 wt% alumina, 15-35 wt% kaolin and water are uniformly mixed, with the solid / water weight ratio in the mixture being 0.2-0.5, spray-formed and dried to obtain a catalyst.

5. The method for preparing the catalyst according to claim 1, characterized in that: The inlet temperature of the spray forming is 480-600°C, the tail gas temperature is 200-300°C, the spray pressure is 6-10Mpa, the roasting temperature is 550-600°C, and the roasting time is 2-5 hours.

6. Use of the catalyst according to claim 1 for synthesizing 3-methylpyridine from acrolein, propionaldehyde and ammonia, characterized in that: The reaction conditions were: fluidized bed reactor, 0.1 MPa, 460°C, acrolein / propionaldehyde / ammonia molar ratio 1 / 1 / 3, and aldehyde weight space velocity 0.6 h -1 , N2 flow rate is 60ml / min.

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