A catalyst for the continuous methylation of m-cresol, its preparation and use

Abstract

The application provides a catalyst for continuous methylation of m-cresol, a preparation method and application thereof. The catalyst comprises a carrier and an active substance loaded on the carrier; wherein the carrier is calcined pseudo-boehmite, and the active substance comprises a platinum compound and a heteropoly acid; the platinum compound accounts for 0.05-5% of the mass of the carrier; and the heteropoly acid accounts for 0.5-10% of the mass of the carrier. The platinum compound in the catalyst has a function of inhibiting coking, and loading the platinum compound on the carrier can inhibit the speed of olefin polymerization and coking on the catalyst, so that the stability of the catalyst is improved, the service life of the catalyst is prolonged, and the catalyst can be reactivated after the activity of the catalyst is reduced. Meanwhile, the catalyst loaded with the heteropoly acid can appropriately increase the acidity of the catalyst, so that the catalytic activity of the catalyst is improved; and the multi-atom in the heteropoly acid can also adjust the reaction site of the catalyst, so that the selectivity of m-cresol and olefin reaction is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of fine chemicals synthesis, in particular to a catalyst for continuous metha-cresol alkylation, its preparation method and application. BACKGROUND

[0002] The alkylation reaction of m-cresol and olefin mainly refers to the alkylation of m-cresol and propylene or isobutylene, which is used for preparing 2-isopropyl-5-methylphenol (thymol) or 2-tert-butyl-5-methylphenol.

[0003] The synthesis of 2-isopropyl-5-methylphenol is basically achieved by using m-cresol and various isopropylating reagents such as propylene, isopropyl alcohol or isopropyl halide, etc. In the earlier research, aluminum chloride or sulfuric acid is generally used as a catalyst, isopropyl halide and m-cresol are used as raw materials, and dichloroethane is used as a solvent to prepare 2-isopropyl-5-methylphenol, which has a high yield. However, a large amount of solvent is required, and the post-reaction treatment is complex and the environmental pollution is serious. In the research of K. Shanmugapriya et al. on the synthesis of 2-isopropyl-5-methylphenol by using Al-MCM-41 molecular sieve as a catalyst to catalyze the reaction of m-cresol and isopropyl acetate, the conversion rate of m-cresol is about 70%, and the product selectivity is 70% to 88%, but the catalyst has a very short service life. The process described in US4086283 mainly includes continuous alkylation of m-cresol and propylene at a temperature of 350 to 365 ℃ and a pressure of 50 bar. Although the yield is relatively high, the conversion rate is not high and the operating conditions are very harsh.

[0004] The synthesis of 2-tert-butyl-5-methylphenol is mainly achieved by using m-cresol and isobutene to synthesize by a Friedel-Crafts reaction. Studies have shown that isobutene gas is used as an alkylating agent, and an acidic ion exchange resin is used as a catalyst for the reaction. However, the acidic ion exchange resin is expensive, the conversion rate is not high, repeated reactions are required, impurities are easily produced, and the selectivity is not high. SUMMARY

[0005] The main purpose of the present application is to provide a catalyst for continuous metha-cresol alkylation, its preparation method and application, so as to solve the problems of low activity, short service life and poor selectivity of the catalyst for continuous metha-cresol alkylation in the prior art.

[0006] In order to achieve the above-mentioned purpose, according to one aspect of the present application, a catalyst for continuous metha-cresol alkylation is provided, which comprises a carrier and an active substance supported on the carrier; wherein the carrier is calcined pseudo-boehmite, and the active substance comprises a platinum compound and a heteropoly acid; the platinum compound accounts for 0.05 to 5% of the mass of the carrier; and the heteropoly acid accounts for 0.5 to 10% of the mass of the carrier.

[0007] Further, the platinum compound is selected from one or more of platinum dichloride, platinum trichloride, platinum tetrachloride and chloroplatinic acid, preferably platinum tetrachloride and / or chloroplatinic acid, more preferably chloroplatinic acid; and the heteropoly acid is selected from one or more of phosphomolybdic acid, phosphotungstic acid, silicotungstic acid and silicomolybdic acid, preferably silicomolybdic acid and / or silicotungstic acid, more preferably silicotungstic acid.

[0008] To achieve the above object, according to one aspect of the present application, there is provided a preparation method of the above-mentioned catalyst, comprising: performing a first calcination reaction on pseudo-boehmite under an air atmosphere to obtain calcined pseudo-boehmite; mixing platinum compound, heteropoly acid, water and the calcined pseudo-boehmite at room temperature and drying to obtain pseudo-boehmite loaded with platinum compound and heteropoly acid; performing a second calcination reaction on the pseudo-boehmite loaded with platinum compound and heteropoly acid under an air atmosphere to obtain a catalyst for continuous alkylation of m-cresol.

[0009] Further, the first calcination reaction is performed at a temperature of 500-700°C, preferably for 4-8h; and the second calcination reaction is performed at a temperature of 500-800°C, preferably for 4-10h.

[0010] Further, the mass ratio of platinum compound, heteropoly acid and calcined pseudo-boehmite is 0.05-5:0.5-10:100.

[0011] According to another aspect of the present application, there is provided a continuous alkylation reaction of m-cresol, comprising: feeding m-cresol, olefin and the above-mentioned catalyst into a fixed bed reactor for reaction.

[0012] Further, the fixed bed reactor is divided into a preheating section, a reaction section and a cooling section, and the continuous alkylation reaction of m-cresol comprises: mixing the catalyst with quartz sand and filling the reaction section of the fixed bed reactor; mixing m-cresol with olefin, and then feeding the mixture into the preheating section for preheating and vaporization to obtain a vaporization product; feeding the vaporization product into the reaction section filled with the catalyst for reaction to obtain a crude product; and performing gas-liquid separation on the crude product, and then performing vacuum rectification on the separated liquid mixture to obtain an m-cresol alkylate product; preferably, the size of the reaction section is Preferably, the reaction is performed for 15-35min.

[0013] Further, the olefin is selected from propylene and / or isobutylene, and the molar ratio of m-cresol to olefin is 1:1.05-1:2, preferably 1:1.1-1:1.6.

[0014] Further, the m-cresol is fed by a metering pump at a speed of 0.03-0.5g / min; and / or the mass space velocity of m-cresol is 0.09-1.5h -1; and / or the olefin is fed through a gas mass flow meter, the gas mass flow of the olefin being 0.013 g / min to 0.31 g / min; preferably the mass ratio of the catalyst to quartz sand is 1:2 to 1:5.

[0015] Further, the temperature of the reaction section is 230 to 280℃, the temperature of the preheating section is 280 to 320℃, and the temperature of the cooling section is 220 to 250℃.

[0016] By applying the technical solution of the present application, the catalyst of the present application takes the calcined pseudo-boehmite as the carrier, and the main active ingredient in the calcined pseudo-boehmite is γ-Al2O3. The active ingredient contains more aluminum and has higher catalytic activity. The platinum compound has the function of inhibiting coking, and the platinum compound loaded on the carrier can inhibit the speed of olefin polymerization and coking on the catalyst, so that the stability of the catalyst is improved, thereby prolonging the service life of the catalyst and reactivating the catalyst after the activity of the catalyst decreases. Meanwhile, the catalyst of the present application loads heteropoly acid in the range of 0.5 to 10% of the mass of the carrier. The heteropoly acid can appropriately increase the acidity of the catalyst, thereby improving the catalytic activity of the catalyst; and the multi-atom in the heteropoly acid can also adjust the reaction site of the catalyst, thereby improving the selectivity of the reaction of m-cresol and olefin. DETAILED DESCRIPTION

[0017] It should be noted that the embodiments in the present application and the features in the embodiments can be combined with each other without conflict. The present application will be described in detail below with reference to the embodiments.

[0018] As analyzed in the background art, there are problems of low catalyst activity, short service life and poor selectivity in the prior art for continuous alkylation of m-cresol. In order to solve these problems, the present application provides a catalyst for continuous alkylation of m-cresol, a preparation method and application thereof.

[0019] In a typical embodiment of the present application, the present application provides a catalyst for continuous alkylation of m-cresol, which comprises a carrier and an active substance loaded on the carrier; wherein the carrier is calcined pseudo-boehmite, and the active substance comprises a platinum compound and a heteropoly acid; the platinum compound accounts for 0.05 to 5% (for example 0.05%, 0.1%, 1%, 1.5%, 2%, 2.5%, 2.7%, 3%, 3.2%, 3.5%, 3.7%, 4%, 4.3%, 4.5%, 4.8%, 5%) of the mass of the carrier; and the heteropoly acid accounts for 0.5 to 10% (preferably 1 to 5%, for example 0.5%, 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5%, 5.5%, 6%, 6.5%, 7%, 7.5%, 8%, 8.5%, 9%, 9.5%, 10%) of the mass of the carrier.

[0020] In the reaction of m-cresol and olefin alkylation, due to the presence of the benzene ring, the structure of m-cresol is relatively stable, and it is difficult to carry out alkylation, and the conversion rate is not high; and in the process of alkylation, m-cresol and olefin can generate other isomers and disubstituted m-cresol, and there is a problem of selectivity, so the yield of the target product is low; at the same time, the olefin used in alkylation is easy to polymerize and coking under acidic conditions, covering the active sites of the catalyst, resulting in short service life of the catalyst; the catalyst of the present application can effectively solve the problems of low activity and short service life of the catalyst in the alkylation reaction of m-cresol and olefin.

[0021] The catalyst of the present application selects calcined pseudo-boehmite as the carrier, and the main active ingredient in the calcined pseudo-boehmite is γ-Al2O3, which contains more aluminum and has higher catalytic activity. Platinum compounds have the function of inhibiting coking, and loading platinum compounds on the carrier can inhibit the speed of olefin polymerization and coking on the catalyst, so that the stability of the catalyst is improved, thereby prolonging the service life of the catalyst and reactivating the catalyst after the activity decreases. At the same time, the catalyst of the present application loads heteropoly acid in the range of 0.5-10% of the mass of the carrier, and the heteropoly acid can appropriately increase the acidity of the catalyst, thereby improving the catalytic activity of the catalyst; and the multi-atom in the heteropoly acid can also adjust the reaction sites of the catalyst, thereby improving the selectivity of the reaction of m-cresol and olefin.

[0022] The present application does not have special restrictions on the types of platinum compounds and heteropoly acids, and the commonly used platinum compounds and heteropoly acids in the art can be applied to the present application. In some embodiments, the above-mentioned platinum compounds are selected from one or more of platinum dichloride, platinum trichloride, platinum tetrachloride and chloroplatinic acid, preferably the above-mentioned platinum compounds are platinum tetrachloride and / or chloroplatinic acid, more preferably chloroplatinic acid; the heteropoly acid is selected from one or more of phosphomolybdic acid, phosphotungstic acid, silicotungstic acid and silicomolybdic acid, preferably silicomolybdic acid and / or silicotungstic acid, more preferably silicotungstic acid.

[0023] In another typical embodiment of the present application, a preparation method of the above-mentioned catalyst is provided, which comprises: carrying out a first calcination reaction on pseudo-boehmite in an air atmosphere to obtain calcined pseudo-boehmite; mixing platinum compounds, heteropoly acid, water and calcined pseudo-boehmite at room temperature and drying to obtain pseudo-boehmite loaded with platinum compounds and heteropoly acid; carrying out a second calcination reaction on the pseudo-boehmite loaded with platinum compounds and heteropoly acid in an air atmosphere to obtain a catalyst for continuous alkylation of m-cresol.

[0024] The pseudo-boehmite is first calcined to obtain γ-Al2O3, which is prepared into a carrier, and then a platinum compound and a heteropoly acid are loaded on the calcined pseudo-boehmite, and the catalyst is prepared by calcining again. The method for preparing the catalyst is simple and has low production cost. The catalyst loaded with the platinum compound prepared by the method has the functions of inhibiting coking and prolonging the service life of the catalyst, and the catalytic activity of the catalyst is improved by loading the heteropoly acid.

[0025] In some embodiments, the step of the preparation method further comprises crushing and sieving the catalyst into particles with a size of 20-40 mesh. When the particle size is within this range, the catalyst has high catalytic activity. If the particle size is too large, the activity of the catalyst will be reduced, and if the particle size is too small, the reaction will be hindered during the reaction process.

[0026] The first calcination reaction can refer to the process conditions commonly used in the prior art for preparing a pseudo-boehmite carrier. In some embodiments, the temperature of the first calcination reaction is 500-700°C, and the time of the first calcination reaction is 4-8h. When the catalyst is prepared, the calcination temperature will affect the activity of the catalyst. In some embodiments, the temperature of the second calcination reaction is 500-800°C, and the time of the second calcination reaction is 4-10h.

[0027] In order to remove the solvent without damaging the structure of the carrier and the active substance, the temperature of the drying is preferably 100-150°C, and the time of the drying is preferably 4-10h.

[0028] In order to further improve the activity of the catalyst and prevent coking during the polymerization of olefins, in some embodiments, the mass ratio of the platinum compound, the heteropoly acid and the calcined pseudo-boehmite is 0.05-5:0.5-10:100. Too much platinum compound loaded on the catalyst will result in excessive acidity of the catalyst and a decrease in selectivity; too much heteropoly acid will form large crystal grains, the concentration of surface protons will decrease, the activity of the catalyst will decrease, and too much heteropoly acid will result in excessive acidity of the catalyst, making the reaction too violent to control the selectivity of the product, increasing the side reactions of the product and reducing the selectivity.

[0029] In another typical embodiment of the present application, a continuous m-cresol alkylation reaction is provided, which comprises: feeding m-cresol, olefins and the above-mentioned catalyst into a fixed bed reactor for reaction.

[0030] In the present application, the selectivity of the reaction of m-cresol and olefins and the yield of the target product can be improved by using the above-mentioned catalyst; at the same time, no other solvent is involved in the alkylation process, and the catalyst can be repeatedly used, which reduces the discharge of three wastes and has little pollution. Combined with the fixed bed reactor, continuous production can be realized, which has the advantages of high production efficiency, low cost, and good safety.

[0031] In order to further improve the production efficiency and realize continuous production, in some embodiments, the fixed bed reactor is divided into a preheating section, a reaction section and a cooling section, and the continuous m-cresol alkylation reaction comprises: mixing the catalyst with quartz sand and filling the reaction section of the fixed bed reactor; mixing the m-cresol with the olefin and placing the mixture in the preheating section for preheating and vaporization to obtain a vaporization product; placing the vaporization product in the reaction section filled with the catalyst for reaction to obtain a crude product; performing gas-liquid separation on the crude product, and performing vacuum rectification on the separated liquid mixture to obtain the m-cresol alkylation product, and recycling the gaseous product; preferably, the size of the reaction section is 0.5-1.5 m. Preferably, the reaction time is 15-35 min.

[0032] The type of the olefin is not particularly limited in the present application, and in some embodiments, the olefin is preferably selected from propylene and / or isobutylene.

[0033] In some embodiments, the molar ratio of m-cresol to olefin is controlled to be 1:1.05-1:2, preferably 1:1.1-1:1.6. In order to ensure sufficient m-cresol reaction, the present application appropriately allows the olefin to be in excess, thereby improving the conversion rate of the raw material m-cresol and the selectivity of the product, and the excess olefin is recycled. However, too much excess propylene will produce other by-products, resulting in a decrease in selectivity. The by-products are generally high-boiling substances that are not in a vaporized state in the system and are easily attached to the catalyst, resulting in a decrease in the service life of the catalyst. Excess m-cresol will result in a decrease in the conversion rate. Since the above-mentioned alkylation reaction is a continuous reaction, the above-mentioned catalyst is filled once, and the filling amount of the catalyst is 20-40 g.

[0034] In some embodiments, the m-cresol is fed by a metering pump, and the feeding speed is 0.03-0.5 g / min, for example, it can be 0.03 g / min, 0.05 g / min, 0.1 g / min, 0.13 g / min, 0.18 g / min, 0.2 g / min, 0.24 g / min, 0.27 g / min, 0.3 g / min, 0.34 g / min, 0.36 g / min, 0.4 g / min, 0.42 g / min, 0.46 g / min, 0.5 g / min; and / or the mass space velocity of the m-cresol is 0.09-1.5 h -1; and / or the olefin is fed through a gas mass flow meter, the gas mass flow of the olefin being 0.013-0.31 g / min, for example, it can be 0.013 g / min, 0.024 g / min, 0.035 g / min, 0.043 g / min, 0.058 g / min, 0.066 g / min, 0.074 g / min, 0.086 g / min, 0.091 g / min, 0.13 g / min, 0.25 g / min, 0.31 g / min; preferably, the mass ratio of the catalyst to the quartz sand is 1:2-1:5, preferably, it is 1:3-1:4. Since the alkylation reaction is an exothermic reaction, too fast feeding speed will cause excessive heat release of the reaction, and too slow feeding speed will cause the increase of impurities, thereby causing the decrease of selectivity, the feeding speed is controlled in the preferred range in the present application, the reaction temperature can be kept unchanged, and the risk of excessive heat release is reduced.

[0035] In order to make the m-cresol react completely with the olefin without destroying the structure of the target product, in some embodiments, the temperature of the reaction section is 230-280°C (for example, 230°C, 235°C, 240°C, 245°C, 250°C, 255°C, 260°C, 265°C, 270°C, 275°C, 280°C), the temperature of the preheating section is 280-320°C (for example, 280°C, 285°C, 290°C, 295°C, 300°C, 305°C, 310°C, 315°C, 320°C), and the temperature of the cooling section is 220-250°C (for example, 220°C, 225°C, 230°C, 235°C, 240°C, 245°C, 250°C). The above reaction is carried out at normal pressure.

[0036] The present application is further described in detail below in connection with specific embodiments, which cannot be understood as limiting the scope of the present application.

[0037] Alkylation reaction

[0038] The equation of the reaction of m-cresol with the olefin is as follows:

[0039] wherein R is isopropyl or tert-butyl.

[0040] Example 1

[0041] Preparation of catalyst

[0042] 100 g of pseudoboehmite was first calcined at 600°C in a muffle furnace for 6 h to obtain calcined pseudoboehmite;

[0043] At room temperature, 2 g of tungstosilicic acid and 0.1 g of chloroplatinic acid were dissolved in 100 g of purified water, and then calcined pseudo-boehmite was added, stirred uniformly, and left to stand. The mixture was placed in an oven and dried at 120°C for 6 h to obtain pseudo-boehmite loaded with platinum compounds and heteropoly acids;

[0044] The pseudo-boehmite loaded with platinum compounds and heteropoly acids was placed in a muffle furnace and subjected to second calcination at 600°C for 5 h to obtain a catalyst. After the catalyst was cooled, it was sieved to obtain a catalyst CAT-1 with a size of 20-40 mesh.

[0045] The continuous alkylation reaction of m-cresol was carried out as follows:

[0046] 20 g of CAT-1 was mixed with 60 g of quartz sand and filled into a fixed bed reaction section. The size of the reaction section was 20 mm x 20 mm x 100 mm. The fixed bed was programmed to be heated to 280°C in the preheating section, 260°C in the reaction section, and 240°C in the cooling section. M-cresol was pumped into the preheating section at a rate of 0.2 g / min by a metering pump, and propylene was controlled to enter the preheating section at a rate of 0.086 g / min by a gas flow meter. The molar ratio of m-cresol to propylene was 1:1.1.

[0047] After the mixture was vaporized in the preheating section, the vaporized product was obtained. The vaporized product was sent to the reaction section for reaction for 25 min, and a sample was taken at the outlet. The conversion rate of m-cresol was 89% and the selectivity of 2-isopropyl-5-methylphenol (thymol) was 97% as detected by gas chromatography agilent 7890A. The continuous operation lasted for 1500 h, and the conversion rate of m-cresol did not show a significant decrease, and the selectivity remained unchanged.

[0048] Example 2

[0049] Different from Example 1, the molar ratio of m-cresol to propylene was 1:1.3. The conversion rate of m-cresol was 93%, and the selectivity of 2-isopropyl-5-methylphenol (thymol) was 97%. The continuous operation lasted for 1500 h, and the conversion rate of m-cresol did not show a significant decrease, and the selectivity remained unchanged.

[0050] Example 3

[0051] Preparation of catalyst

[0052] 50 g of pseudo-boehmite was subjected to first calcination at 600°C in a muffle furnace for 6 h to obtain calcined pseudo-boehmite;

[0053] At room temperature, 1 g of tungstosilicic acid and 0.1 g of chloroplatinic acid were dissolved in 50 g of purified water, and then the calcined carrier was added, stirred uniformly, and left to stand. The mixture was placed in an oven and dried at 120°C for 6 h to obtain pseudo-boehmite loaded with platinum compounds and heteropoly acids;

[0054] The above supported platinum compound and pseudo-boehmite of heteropoly acid were put into a muffle furnace for second calcination at 600°C for 5h to obtain a catalyst, which was sieved after cooling to obtain a catalyst CAT-2 with a size of 20-40 mesh.

[0055] The continuous metha-cresol alkylation reaction was carried out as follows:

[0056] 20g of CAT-2 was weighed and mixed with 60g of quartz sand to fill a fixed bed reaction section, which had a size of 20mm in diameter and 300mm in length. The fixed bed was programmed to be heated to 280°C in a preheating section, 260°C in a reaction section and 240°C in a cooling section, metha-cresol was pumped into the preheating section at a speed of 0.2g / min by a metering pump, and propylene was controlled to enter the preheating section at a speed of 0.013g / min by a gas flow meter, with a molar ratio of metha-cresol to propylene being 1:1.3.

[0057] After the mixture was vaporized in the preheating section, a vaporized product was obtained; the vaporized product was sent into the reaction section for reaction for 35min, and a sample was taken at the discharge to detect the conversion rate of metha-cresol by gas chromatography, which was 96%, and the selectivity of 2-isopropyl-5-methylphenol (thymol) was 97%. The continuous operation lasted for 1500h, and no obvious decrease in the conversion rate of metha-cresol was observed, and the selectivity remained unchanged.

[0058] Example 4

[0059] Different from Example 3, the molar ratio of metha-cresol to propylene was 1:1.4. The conversion rate of metha-cresol was 90%, and the selectivity of 2-isopropyl-5-methylphenol (thymol) was 96%. The continuous operation lasted for 1500h, and no obvious decrease in the conversion rate of metha-cresol was observed, and the selectivity remained unchanged.

[0060] Example 5

[0061] Different from Example 3, 1g of silicotungstic acid and 0.1g of platinum tetrachloride were dissolved in 50g of purified water to obtain a catalyst CAT-3 in the process of preparing the catalyst. In the alkylation reaction, the molar ratio of metha-cresol to propylene was 1:1.4. The conversion rate of metha-cresol was 89%, and the selectivity of 2-isopropyl-5-methylphenol (thymol) was 95%. The continuous operation lasted for 1500h, and no obvious decrease in the conversion rate of metha-cresol was observed, and the selectivity remained unchanged.

[0062] Example 6

[0063] Preparation of a catalyst

[0064] 50g of pseudo-boehmite was calcined at 600°C for 6h in a muffle furnace to obtain calcined pseudo-boehmite;

[0065] At room temperature, 0.5 g of tungstosilicic acid and 0.05 g of chloroplatinic acid were dissolved in 50 g of purified water, and then a calcined carrier was added, stirred uniformly, and left to stand. The mixture was dried in an oven at 120°C for 6 h to obtain a pseudo-alumina loaded with platinum compounds and heteropoly acid;

[0066] The pseudo-alumina loaded with platinum compounds and heteropoly acid was placed in a muffle furnace and subjected to a second calcination at 600°C for 5 h to obtain a catalyst. After the catalyst was cooled, it was sieved to obtain a catalyst CAT-4 with a size of 20-40 mesh.

[0067] The continuous alkylation reaction of m-cresol was carried out as follows:

[0068] 20 g of CAT-4 was mixed with 60 g of quartz sand and filled into a fixed bed reaction section. The size of the reaction section was 30 cm x 30 cm x 30 cm. The fixed bed was programmed to be heated to 280°C in the preheating section, 250°C in the reaction section, and 240°C in the cooling section. M-cresol was pumped into the preheating section at a rate of 0.2 g / min using a metering pump, and isobutylene was controlled to enter the preheating section at a rate of 0.135 g / min using a gas flow meter. The molar ratio of m-cresol to isobutylene was 1:1.3. After vaporization in the preheating section, a vaporization product was obtained.

[0069] The vaporization product was sent to the reaction section for reaction for 15 min, and a sample was taken at the outlet. Gas chromatography showed that the conversion rate of m-cresol was 99%, and the selectivity of 2-isopropyl-5-methylphenol (thymol) was 96%. The continuous operation lasted for 1500 h, and there was no obvious decrease in the conversion rate of m-cresol, and the selectivity remained unchanged.

[0070] Example 7

[0071] Different from Example 6, 0.5 g of tungstosilicic acid and 0.1 g of chloroplatinic acid were dissolved in 50 g of purified water to obtain a catalyst CAT-5.

[0072] Example 8

[0073] Different from Example 6, 0.5 g of tungstosilicic acid and 0.1 g of chloroplatinic acid were dissolved in 50 g of purified water to obtain a catalyst CAT-5.

[0074] Example 9

[0075] Different from Example 1, 0.5 g of tungstosilicic acid and 0.05 g of chloroplatinic acid were dissolved in 100 g of purified water to obtain a catalyst CAT-7.

[0076] Example 10

[0077] Different from Example 1, 10 g of tungstosilicic acid and 5 g of chloroplatinic acid were dissolved in 100 g of purified water to obtain a catalyst CAT-8.

[0078] Example 11

[0079] Unlike Example 1, 5 g of silicotungstic acid and 2.5 g of chloroplatinic acid were dissolved in 100 g of purified water to obtain a catalyst CAT-9.

[0080] Example 12

[0081] Unlike Example 1, 0.5 g of silicotungstic acid and 6 g of chloroplatinic acid were dissolved in 100 g of purified water to obtain a catalyst CAT-10.

[0082] Example 13

[0083] Unlike Example 1, 0.5 g of silicotungstic acid and 0.03 g of chloroplatinic acid were dissolved in 100 g of purified water to obtain a catalyst CAT-11.

[0084] Example 14

[0085] Unlike Example 1, 12 g of silicotungstic acid and 6 g of chloroplatinic acid were dissolved in 100 g of purified water to obtain a catalyst CAT-12.

[0086] Example 15

[0087] Unlike Example 1, 0.2 g of silicotungstic acid and 6 g of chloroplatinic acid were dissolved in 100 g of purified water to obtain a catalyst CAT-13.

[0088] Example 16

[0089] Preparation of a catalyst

[0090] 100 g of pseudoboehmite was first calcined at 500°C for 4 h in a muffle furnace to obtain calcined pseudoboehmite;

[0091] 2 g of phosphotungstic acid and 0.1 g of dichloroplatinic acid were dissolved in 100 g of purified water at room temperature, and the calcined carrier was added thereto, stirred uniformly, and left to stand, and then dried at 100°C for 6 h in an oven to obtain a pseudoboehmite loaded with platinum compounds and heteropoly acids;

[0092] The pseudoboehmite loaded with platinum compounds and heteropoly acids was placed in a muffle furnace and second calcined at 500°C for 4 h to obtain a catalyst, and the catalyst was cooled and sieved to obtain a catalyst CAT-14 of 20-40 mesh.

[0093] The m-cresol continuous alkylation reaction was performed in the same manner as in Example 1.

[0094] Example 17

[0095] Preparation of a catalyst

[0096] 100 g of pseudo-boehmite was first calcined at 700℃ for 8h in a muffle furnace to obtain calcined pseudo-boehmite;

[0097] 2 g of phosphomolybdic acid and 0.1 g of chloroplatinic acid were dissolved in 100 g of purified water at room temperature, and then the calcined carrier was added and stirred uniformly and left to stand. The mixture was placed in an oven and dried at 150℃ for 10h to obtain pseudo-boehmite loaded with platinum compounds and heteropoly acids;

[0098] The pseudo-boehmite loaded with platinum compounds and heteropoly acids was placed in a muffle furnace and second calcined at 800℃ for 10h to obtain a catalyst. After the catalyst was cooled, it was sieved to obtain a 20-40 mesh catalyst CAT-15.

[0099] The steps of the continuous alkylation reaction of m-cresol were the same as in Example 1.

[0100] Example 18

[0101] The process of preparing the catalyst was the same as in Example 1.

[0102] The steps of the continuous alkylation reaction of m-cresol were different from those in Example 1 in that the preheating section was at 320℃, the reaction section was at 280℃, and the cooling section was at 250℃.

[0103] Example 19

[0104] The process of preparing the catalyst was the same as in Example 1.

[0105] The steps of the continuous alkylation reaction of m-cresol were different from those in Example 1 in that the preheating section was at 300℃, the reaction section was at 230℃, and the cooling section was at 220℃.

[0106] Example 20

[0107] The process of preparing the catalyst was the same as in Example 1.

[0108] The steps of the continuous alkylation reaction of m-cresol were different from those in Example 1 in that the molar ratio of m-cresol to propylene was 1:1.05.

[0109] Example 21

[0110] The process of preparing the catalyst was the same as in Example 1.

[0111] The steps of the continuous alkylation reaction of m-cresol were different from those in Example 1 in that the molar ratio of m-cresol to propylene was 1:2.

[0112] Example 22

[0113] The process of preparing the catalyst was the same as in Example 1.

[0114] The steps of the continuous alkylation reaction of m-cresol were different from those in Example 1 in that the molar ratio of m-cresol to propylene was 1:0.85.

[0115] Example 23

[0116] The process of preparing catalyst is the same as Example 1.

[0117] The procedure of continuous alkylation of m-cresol is different from Example 1 in that the feeding rate of m-cresol is 0.03 g / min.

[0118] Example 24

[0119] The process of preparing catalyst is the same as Example 1.

[0120] The procedure of continuous alkylation of m-cresol is different from Example 1 in that the feeding rate of m-cresol is 0.5 g / min.

[0121] Example 25

[0122] The process of preparing catalyst is the same as Example 1.

[0123] The procedure of continuous alkylation of m-cresol is different from Example 1 in that the feeding rate of m-cresol is 0.7 g / min.

[0124] Example 26

[0125] The process of preparing catalyst is the same as Example 1.

[0126] The procedure of continuous alkylation of m-cresol is different from Example 1 in that the feeding rate of propylene is 0.31 g / min.

[0127] Comparative Example 1

[0128] CAT-2 is selected as catalyst, propylene is replaced by isopropyl alcohol, the molar ratio of m-cresol and isopropyl alcohol is 1:2, the continuous reaction is carried out for 40 min, and the sample is analyzed by gas chromatography. The conversion rate of m-cresol is 78%, the selectivity of 2-isopropyl-5-methylphenol is 81%, the continuous reaction is carried out for 12 h, the sample is taken, the conversion rate of m-cresol is reduced by 50%, and the catalyst is gradually deactivated. Because water is generated after the reaction of isopropyl alcohol, the structure of the catalyst is destroyed by water, and the deactivation is faster.

[0129] Comparative Example 2

[0130] CAT-2 is selected as catalyst, m-cresol and isopropyl alcohol are fed, the molar ratio of m-cresol and isopropyl alcohol is 1:5, the above materials are fed into the high-pressure reaction kettle at one time, nitrogen is replaced, the temperature is raised to 260°C, the continuous reaction is carried out for 8 h, and the sample is analyzed by gas chromatography. The conversion rate of m-cresol is 67%, and the selectivity of 2-isopropyl-5-methylphenol is 58%.

[0131] Comparative Example 3

[0132] Select CAT-5 as catalyst, isobutene is replaced by isobutanol, m-cresol and isobutanol molar ratio 1:3, according to the method of example 7, after 40 min continuous reaction, sample gas chromatography analysis, m-cresol conversion rate 58%, 2-tert-butyl-5-methylphenol selectivity 61%, after 12 h continuous reaction, sample, m-cresol conversion rate decreased 50%, the catalyst gradually deactivated, because the reaction generates water after using isobutanol, water destroys the structure of the catalyst, leading to faster deactivation.

[0133] Comparative example 4

[0134] Select CAT-5 as catalyst, isobutene is replaced by isobutanol, m-cresol and isobutanol molar ratio 1:4, m-cresol and isobutanol molar ratio 1:3, the above materials are added into the high-pressure reaction kettle at one time, after nitrogen replacement, the temperature is raised to 250°C, after 8 h continuous reaction, sample gas chromatography analysis, m-cresol conversion rate 37%, 2-tert-butyl-5-methylphenol selectivity 18%.

[0135] Comparative example 5

[0136] Preparation of catalyst

[0137] Take 50 g of pseudo-boehmite and calcine in a muffle furnace at 600°C for 6 h, then add 50 g of purified water to dissolve, stir uniformly, place in an oven to dry at 120°C for 6 h, then place in a muffle furnace to calcine at 600°C for 5 h, to obtain calcined pseudo-boehmite, after cooling, sieve to 20-40 mesh to obtain catalyst CAT-0.

[0138] The steps of continuous m-cresol alkylation reaction are as follows:

[0139] Take 20 g and mix with 60 g of quartz sand to fill into the fixed bed reaction section, the size of the reaction section is The fixed bed is programmed to preheat section 280°C, reaction section 250°C, cooling section 240°C, m-cresol is pumped into the preheating section at a speed of 0.2 g / min by a metering pump, propylene is controlled to enter the preheating section at a speed of 0.086 g / min by a gas flow meter, molar ratio of m-cresol and propylene 1:1.3.

[0140] After vaporization and mixing in the preheating section, the vaporization product is obtained; the vaporization product is sent into the reaction section for reaction, sample is taken at the discharge, m-cresol conversion rate 40% is detected by gas chromatography, 2-isopropyl-5-methylphenol (thymol) selectivity 54%. After 72 h continuous operation, m-cresol conversion rate begins to decrease obviously, selectivity decreases slightly, after 100 h operation, the catalyst is basically deactivated.

[0141] Comparative example 6

[0142] Selecting catalyst CAT-0, 20 g is weighed and mixed with 60 g of quartz sand to fill the fixed bed reaction section. The fixed bed is programmed to heat to 280°C in the preheating section, 250°C in the reaction section, and 240°C in the cooling section. The m-cresol is pumped into the preheating section at a rate of 0.2 g / min using a metering pump, and the isobutylene is controlled to enter the preheating section at a rate of 0.086 g / min using a gas flow meter. The molar ratio of m-cresol to isobutylene is 1:1.3. After vaporization and mixing in the preheating section, the mixture enters the reaction section to react. Samples are taken at the outlet, and the m-cresol conversion rate is detected by gas chromatography to be 47%, and the 2-tert-butyl-5-methylphenol selectivity is 38%. After 65 h of continuous operation, the m-cresol conversion rate begins to decrease significantly, and the selectivity decreases slightly. After 85 h of operation, the catalyst is essentially deactivated.

[0143] Comparative Example 7

[0144] ZSM-5 molecular sieve is selected as the catalyst.

[0145] 20 g of ZSM-5 molecular sieve catalyst is weighed and mixed with 60 g of quartz sand to fill the fixed bed reaction section. The fixed bed is programmed to heat to 280°C in the preheating section, 250°C in the reaction section, and 240°C in the cooling section. The m-cresol is pumped into the preheating section at a rate of 0.2 g / min using a metering pump, and the propylene is controlled to enter the preheating section at a rate of 0.086 g / min using a gas flow meter. The molar ratio of m-cresol to propylene is 1:1.3. After vaporization and mixing in the preheating section, the mixture enters the reaction section to react. Samples are taken at the outlet, and the m-cresol conversion rate is detected by gas chromatography to be 35%, and the 2-isopropyl-5-methylphenol (thymol) selectivity is 87.5%. After 72 h of continuous operation, the m-cresol conversion rate begins to decrease significantly, and the selectivity decreases slightly. After 80 h of operation, the catalyst is essentially deactivated.

[0146] Comparative Example 8

[0147] Preparation of catalyst

[0148] 100 g of pseudoboehmite is first calcined in a muffle furnace at 600°C for 6 h to obtain calcined pseudoboehmite;

[0149] At room temperature, 2 g of silicotungstic acid is dissolved in 100 g of purified water, and then the calcined carrier is added, stirred uniformly, and left to stand. It is placed in an oven and dried at 120°C for 6 h to obtain the pseudoboehmite loaded with heteropoly acid;

[0150] The above-mentioned pseudoboehmite loaded with heteropoly acid is placed in a muffle furnace and second calcined at 600°C for 5 h to obtain the catalyst. After cooling, the catalyst is sieved to obtain the catalyst CAT-16 with a size of 20-40 mesh.

[0151] The steps of the continuous alkylation reaction of m-cresol are the same as in Example 1.

[0152] Comparative Example 9

[0153] Preparation of catalyst

[0154] 100g pseudo-boehmite was first calcined in a muffle furnace at 600℃ for 6h to obtain calcined pseudo-boehmite;

[0155] 0.1g chloroplatinic acid was dissolved in 100g purified water at room temperature, and then the calcined carrier was added and stirred uniformly and placed in an oven to dry at 120℃ for 6h to obtain pseudo-boehmite loaded with platinum compounds;

[0156] The pseudo-boehmite loaded with platinum compounds was placed in a muffle furnace and second calcined at 600℃ for 5h to obtain a catalyst, and the catalyst was sieved after cooling to obtain a catalyst CAT-17 with a size of 20-40 mesh.

[0157] The m-cresol continuous alkylation reaction was the same as that in Example 1.

[0158] Table 1

[0159]

[0160]

[0161] In Example 21, too much propylene was excessive, which produced other by-products, resulting in a decrease in selectivity. The by-products were generally high-boiling substances that were not in a gaseous state in the system and were easily attached to the catalyst, resulting in a decrease in the service life of the catalyst.

[0162] Compared with Example 1, the m-cresol feeding speed was increased in Examples 24-25, and the m-cresol feeding amount was increased in the same time, resulting in a decrease in conversion rate.

[0163] In Example 26, the propylene feeding speed was increased, and the propylene feeding amount was increased in the same time, resulting in a decrease in selectivity.

[0164] As can be seen from the above description, the above-mentioned examples of the present application achieve the following technical effects: The catalyst of the present application selects calcined pseudo-boehmite as a carrier, and the main active ingredient in the calcined pseudo-boehmite is γ-Al2O3, which contains more aluminum and has higher catalytic activity. Platinum compounds have the function of inhibiting coking, and the loading of platinum compounds on the carrier can inhibit the speed of olefin polymerization and coking on the catalyst, so that the stability of the catalyst is improved, thereby prolonging the service life of the catalyst and reactivating the catalyst after the activity of the catalyst decreases. At the same time, the catalyst of the present application loads heteropoly acid in the range of 0.5-10% of the mass of the carrier, and the heteropoly acid can appropriately increase the acidity of the catalyst, thereby improving the catalytic activity of the catalyst; and the multi-atom in the heteropoly acid can also adjust the reaction site of the catalyst, thereby improving the selectivity of m-cresol and olefin reaction.

[0165] The above description is only the preferred embodiment of the present application, and is not intended to limit the present application. The present application can have various changes and modifications for those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A continuous reaction of meta-cresol alkylation, characterized by, The m-cresol continuous alkylation reaction comprises: feeding m-cresol, olefin and catalyst into a fixed bed reactor for reaction; the catalyst comprises a carrier and an active substance supported on the carrier; The carrier is calcined pseudo-boehmite, and the active substance comprises a platinum compound and a heteropoly acid; The platinum compound accounts for 0.05-5% of the mass of the carrier; The heteropoly acid accounts for 0.5-10% of the mass of the carrier; The platinum compound is selected from one or more of dichloroplatinum, trichloroplatinum, tetrachloroplatinum and chloroplatinic acid; The heteropoly acid is selected from one or more of phosphomolybdic acid, phosphotungstic acid, silicotungstic acid and silicomolybdic acid.

2. The continuous meta-cresol alkylation reaction of claim 1, wherein, The platinum compound is selected from tetrachloroplatinum and / or chloroplatinic acid.

3. The continuous meta-cresol alkylation reaction of claim 1, wherein, The platinum compound is chloroplatinic acid.

4. The continuous meta-cresol alkylation reaction of claim 1, wherein, The heteropoly acid is selected from silicomolybdic acid and / or silicotungstic acid.

5. The continuous meta-cresol alkylation reaction of claim 1, wherein, The heteropoly acid is silicotungstic acid.

6. The continuous meta-cresol alkylation reaction of claim 1, wherein, The preparation method of the catalyst comprises: The pseudo-boehmite is subjected to a first calcination reaction in an air atmosphere to obtain the calcined pseudo-boehmite; The platinum compound, the heteropoly acid, water and the calcined pseudo-boehmite are mixed at room temperature and dried to obtain pseudo-boehmite loaded with the platinum compound and the heteropoly acid; The pseudo-boehmite loaded with the platinum compound and the heteropoly acid is subjected to a second calcination reaction in an air atmosphere to obtain the catalyst for m-cresol continuous alkylation.

7. The continuous meta-cresol alkylation reaction of claim 6, wherein, The temperature of the first calcination reaction is 500-700 DEG C.

8. The continuous meta-cresol alkylation reaction of claim 6, wherein, The time of the first calcination reaction is 4-8 h.

9. The m-cresol continuous alkylation reaction of claim 6, wherein, The temperature of the second calcination reaction is 500-800 DEG C.

10. The continuous meta-cresol alkylation reaction of claim 6, wherein, The time of the second calcination reaction is 4-10 h.

11. The continuous meta-cresol alkylation reaction of claim 2, wherein, The mass ratio of the platinum compound, the heteropoly acid and the calcined pseudo-boehmite is 0.05-5:0.5-10:

100.

12. The m-cresol continuous alkylation reaction of claim 1, wherein, The fixed bed reactor is divided into a preheating section, a reaction section and a cooling section, and the m-cresol continuous alkylation reaction comprises: The catalyst is mixed with quartz sand and filled in the reaction section of the fixed bed reactor; The m-cresol is mixed with the olefin, and the mixture is placed in the preheating section for preheating and gasification to obtain a gasification product; The gasification product is placed in the reaction section filled with the catalyst for reaction to obtain a crude product; The crude product is subjected to gas-liquid separation, and the separated liquid mixture is subjected to reduced pressure rectification to obtain an m-cresol alkylation product.

13. The continuous meta-cresol alkylation reaction of claim 12, wherein, The size of the reaction section is φ15*60 cm-φ15*80 cm.

14. The continuous meta-cresol alkylation reaction of claim 12, wherein, The reaction time is 15 min-35 min.

15. The continuous meta-cresol alkylation reaction of claim 1 or 12, wherein, The olefin is selected from propylene and / or isobutylene, and the molar ratio of the m-cresol to the olefin is 1:1.05-1:

2.

16. The continuous meta-cresol alkylation reaction of claim 15, wherein, The molar ratio of the m-cresol to the olefin is 1:1.1-1:1.

6.

17. The m-cresol continuous alkylation reaction of claim 1, wherein, The m-cresol is fed by means of a metering pump at a rate of 0.03 to 0.5 g / min; and / or the mass space velocity of the m-cresol is 0.09 to 1.5 h -1 ; and / or The olefin is fed through a gas mass flow meter, and the gas mass flow of the olefin is 0.013-0.31 g / min.

18. The m-cresol continuous alkylation reaction of claim 12, wherein, The mass ratio of the catalyst to quartz sand is 1:2-1:

5.

19. The m-cresol continuous alkylation reaction of claim 12, wherein, The temperature of the reaction section is 230-280 DEG C, the temperature of the preheating section is 280-320 DEG C, and the temperature of the cooling section is 220-250 DEG C.

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