Preparation method and use method of catalyst for producing 3, 4-dihydro-2H-pyran

Abstract

The invention relates to the field of production of 3, 4-dihydro-2H-pyran, and particularly provides a preparation method and a use method of a catalyst for producing 3, 4-dihydro-2H-pyran, and the catalyst comprises the following components by total mass of 100%: 70-93.88% of alumina; 5 to 28.88% of graphite; 1-20% of chromium oxide; 0.1 to 5.0 percent of copper oxide; 0.01 to 1% of nickel oxide; the aluminum oxide, the graphite, the chromic oxide, the copper oxide, the nickel oxide and the cobalt oxide with the specific mass percentage content are matched for use, so that the problem that the activity is reduced in the use process of the catalyst is greatly improved, the service life of the catalyst is remarkably prolonged, and the selectivity of the catalyst is remarkably improved.

Description

Technical Field

[0001] The invention relates to the production field of 3,4-dihydro-2H-pyran, and in particular to a preparation method and a use method of a catalyst for producing 3,4-dihydro-2H-pyran. Background Art

[0002] 3,4-Dihydro-2H-pyran, molecular formula: C5H8O molecular weight: 84.14, colorless transparent liquid, soluble in alcohol, slightly soluble in chloroform, soluble in most other organic solvents. This product is an organic synthesis intermediate, mainly used as a protective group for hydroxyl groups in chemical reactions.

[0003] Its liquid and vapor are flammable. When heated or exposed to open flames, it poses a serious fire hazard. When heated, it can cause expansion or decomposition, resulting in a sharp rupture of the container. Incomplete combustion can produce toxic carbon monoxide (CO) gas.

[0004] Industrially, 3,4-dihydro-2H-pyran is produced by converting tetrahydrofurfuryl alcohol over a catalyst. The catalysts for 3,4-dihydro-2H-pyran currently available on the market either easily coke on the surface, have a short lifespan, and have a high unit consumption, or have poor selectivity and a low yield of side reactions. Summary of the invention

[0005] Therefore, the technical problem to be solved by the present invention is to overcome the problems in the prior art of catalysts for preparing 3,4-dihydro-2H-pyran, such as easy coking on the surface, poor life, high unit consumption, poor selectivity, many side reactions and low yield, thereby providing a preparation method and use method of a catalyst for producing 3,4-dihydro-2H-pyran.

[0006] The present invention provides a catalyst, which, based on the total mass of the catalyst being 100%, comprises:

[0007]

[0008] Furthermore, the catalyst contains 3.5-8% chromium oxide.

[0009] Furthermore, the bulk density of the catalyst is 0.8-1.2 g / cm 3 , preferably 0.95-1.1 g / cm 3 .

[0010] The present invention also provides a method for preparing the above catalyst, comprising the following steps:

[0011] (1) mixing aluminum oxide, graphite, chromium oxide, copper oxide, nickel oxide and cobalt oxide to obtain a mixture A, adding a solvent, ball milling, drying, adding an alkali solution for activation, filtering, washing with water, and drying to obtain a mixture B;

[0012] (2) Mix the mixture B with the binder, extrude and compress the mixture into tablets, sinter and dry the tablets to obtain the catalyst.

[0013] Furthermore, step (1) satisfies at least one of the following AE:

[0014] A. The solvent is water;

[0015] B. The mass ratio of mixture A to solvent is 50-80:300-500;

[0016] C. Drying temperature is 160-200℃;

[0017] D. The average particle size of the slurry after ball milling is 30-80 μm, preferably 40-60 μm;

[0018] E. The extrusion pressure is 60-80KN.

[0019] Furthermore, step (1) satisfies at least one of the following 1)-6):

[0020] 1) Adding an alkaline solution with a mass concentration of 5-10% for activation;

[0021] 2) the ratio of the mass of the added alkaline solution to the mass of the mixture B is 5:1-3:1; and / or the alkaline substance contained in the alkaline solution is selected from one or more of potassium hydroxide, sodium hydroxide, sodium carbonate and sodium bicarbonate;

[0022] 3) The binder is selected from at least one of polyethylene, styrene, methyl silicone oil and silicone grease;

[0023] 4) The mass ratio of mixture A to binder is 85-100:50-100;

[0024] 5) The sintering temperature is 650-850°C and the sintering time is 4-8 hours;

[0025] 6) Drying temperature is 160-200℃.

[0026] The present invention also provides use of the above-mentioned catalyst or a catalyst prepared by any of the above-mentioned preparation methods in the preparation of 3,4-dihydro-2H-pyran.

[0027] The present invention also provides a method for producing 3,4-dihydro-2H-pyran, wherein tetrahydrofurfuryl alcohol is reacted in the presence of the catalyst for preparing 3,4-dihydro-2H-pyran using tetrahydrofurfuryl alcohol as a raw material or a catalyst prepared by any of the above preparation methods to prepare 3,4-dihydro-2H-pyran; preferably, the reaction temperature is 250-300° C. and the pressure is 0-0.15 Mpa.

[0028] Furthermore, the space velocity of tetrahydrofurfuryl alcohol to the catalyst is 0.5-1.5h -1 , preferably 1.0-1.3h -1 .

[0029] Furthermore, the nitrogen space velocity to the catalyst is 2-4h -1 , preferably 2.4-3.0h -1 .

[0030] The technical solution of the present invention has the following advantages:

[0031] 1. The catalyst for producing 3,4-dihydro-2H-pyran using tetrahydrofurfuryl alcohol as a raw material provided by the present invention comprises, based on the total mass of the catalyst being 100%, 70-93.88% of aluminum oxide; 5-28.88% of graphite; 1-20% of chromium oxide; 0.1-5.0% of copper oxide; 0.01-1% of nickel oxide; and 0.01-0.5% of cobalt oxide. The problem of activity decline during the catalyst activation process is greatly improved by using the above-mentioned aluminum oxide, graphite, chromium oxide, copper oxide, nickel oxide and cobalt oxide in combination with specific mass percentages, and the service life and selectivity of the catalyst are significantly improved. Among them, the combined use of copper oxide, nickel oxide and cobalt oxide greatly inhibits the occurrence of side reactions, while the combined use of chromium oxide inhibits the production of peroxides, and graphite improves thermal conductivity, thereby, on the one hand, reducing the formation of coke, thereby avoiding a large amount of catalyst deactivation, and on the other hand, improving the reaction heat transfer more uniformly and rapidly, which not only reduces the heat required for the reaction, thereby allowing the reaction to proceed at a lower temperature, but more importantly, increases the service life of the catalyst while improving the selectivity and unit processing capacity of the reaction.

[0032] The catalyst of the present invention is innovative on the basis of the preparation process of the traditional catalyst, and a special catalyst for 3,4-dihydro-2H-pyran is developed. After using the catalyst, the raw material conversion rate is 100%, the product selectivity can reach more than 99.0%, and the selectivity can still reach more than 98.3% after continuous use for 120 days. The catalyst and process have a large processing capacity. For the same equipment, the processing capacity can reach 2-2.5 times that of similar catalysts, which improves the equipment utilization rate, greatly reduces the equipment depreciation cost, reduces the catalyst unit consumption, and the stability and life are much higher than the current market catalyst, and the production efficiency is greatly improved.

[0033] 2. The catalyst for producing 3,4-dihydro-2H-pyran using tetrahydrofurfuryl alcohol as a raw material provided by the present invention contains 3.5-8% chromium oxide. By controlling the mass percentage of chromium oxide within the above preferred range, the service life and selectivity of the catalyst can be further improved.

[0034] 3. The catalyst for producing 3,4-dihydro-2H-pyran from tetrahydrofurfuryl alcohol provided by the present invention is controlled to have a bulk density of 0.6-1.6 g / cm 3 , especially 0.75-1.1g / cm 3 , which can further improve the service life and selectivity of the catalyst.

[0035] 4. The method for preparing a catalyst for producing 3,4-dihydro-2H-pyran using tetrahydrofurfuryl alcohol as a raw material provided by the present invention has a simple process, is easy to operate, and has small differences between batches of the prepared catalyst. Moreover, the stability of the catalyst can be improved by activation with an alkaline solution, and the uniformity of the catalyst micropores can be improved, thereby making the reaction more uniform, making the heat transfer inside the catalyst more sufficient, and the heat transfer faster, reducing the presence of factors that reduce the life of the catalyst such as coking caused by excessive local heat release, especially adding an alkaline solution with a concentration of 5-10% for activation. DETAILED DESCRIPTION

[0036] The following examples are provided for a better understanding of the present invention, but are not intended to limit the best mode of implementation, nor to limit the content and protection scope of the present invention. Any product identical or similar to the present invention obtained by anyone under the inspiration of the present invention or by combining the features of the present invention with other prior arts shall fall within the protection scope of the present invention.

[0037] If no specific experimental steps or conditions are specified in the examples, the conventional experimental steps or conditions described in the literature in the field can be used. If no manufacturer is specified for the reagents or instruments used, they are all conventional reagent products that can be obtained commercially.

[0038] Example 1

[0039] This embodiment provides a catalyst for producing 3,4-dihydro-2H-pyran using tetrahydrofurfuryl alcohol as a raw material and a preparation method thereof, wherein the preparation method comprises the following steps:

[0040] (1) 80 kg of aluminum oxide, 15 kg of graphite, 4.6 kg of chromium oxide, 0.35 kg of copper oxide, 0.035 kg of nickel oxide and 0.015 kg of cobalt oxide were mixed to obtain a mixture A; the mixture A was mixed with 800 kg of water, added into a ball mill, and ball-milled to a slurry with an average particle size of 50 μm, and then filtered through a 5 μm sintered carbon rod. 500 kg of 5% (mass percentage) sodium carbonate aqueous solution was added to the filter cake, stirred for 2 hours, and then filtered through a 5 μm sintered carbon rod. After the filtration, the filter cake was rinsed with 200 kg of clean water, and dried at 180° C. and a vacuum degree of -0.097 MPa for 8 hours to obtain a mixture B.

[0041] (2) Mixture B and 80 kg of polyethylene were placed in a shear stirring mixer and stirred at high speed for 2.5 h at a speed of 1450 rpm, and then extruded and pressed into a columnar shape with a diameter of 3.5 mm and a length of 3.5 mm (1.37 mm). The catalyst was sintered at 780° C. for 5 h to obtain a catalyst with a bulk density of 1.01 g / cm 3 .

[0042] Example 2

[0043] The present embodiment provides a catalyst for producing 3,4-dihydro-2H-pyran using tetrahydrofurfuryl alcohol as a raw material and a preparation method thereof, which is basically the same as that of Example 1, except that the amount of raw materials used in preparing the mixture A in step (1) is different. In the present embodiment, 72 kg of aluminum oxide, 20 kg of graphite, 7.7 kg of chromium oxide, 0.25 kg of copper oxide, 0.02 kg of nickel oxide and 0.03 kg of cobalt oxide are mixed to obtain a mixture A.

[0044] Example 3

[0045] The present embodiment provides a catalyst for producing 3,4-dihydro-2H-pyran using tetrahydrofurfuryl alcohol as a raw material and a preparation method thereof, which is basically the same as that of Example 1, except that the amount of raw materials used in preparing the mixture A in step (1) is different. In the present embodiment, 86 kg of aluminum oxide, 10 kg of graphite, 3.6 kg of chromium oxide, 0.33 kg of copper oxide, 0.05 kg of nickel oxide and 0.02 kg of cobalt oxide are mixed to obtain a mixture A.

[0046] Example 4

[0047] The present embodiment provides a catalyst for producing 3,4-dihydro-2H-pyran using tetrahydrofurfuryl alcohol as a raw material and a preparation method thereof, which is basically the same as that of Example 1, except that the amount of raw materials used in preparing the mixture A in step (1) is different. In the present embodiment, 80 kg of aluminum oxide, 10 kg of graphite, 9.8 kg of chromium oxide, 0.18 kg of copper oxide, 0.01 kg of nickel oxide and 0.01 kg of cobalt oxide are mixed to obtain a mixture A.

[0048] Example 5

[0049] The present embodiment provides a catalyst for producing 3,4-dihydro-2H-pyran using tetrahydrofurfuryl alcohol as a raw material and a preparation method thereof, which is basically the same as that of Example 1, except that the amount of raw materials used in preparing the mixture A in step (1) is different. In the present embodiment, 80 kg of aluminum oxide, 10 kg of graphite, 3.4 kg of chromium oxide, 0.52 kg of copper oxide, 0.05 kg of nickel oxide and 0.03 kg of cobalt oxide are mixed to obtain a mixture A.

[0050] Example 6

[0051] The catalyst preparation method is the same as in Example 1, except that the tableting pressure is adjusted to 65 KN, and the bulk density of the prepared catalyst is 0.7 g / cm 3 .

[0052] Example 7

[0053] The catalyst preparation method is the same as that in Example 1, except that the tableting pressure is adjusted to 70 KN. The bulk density of the catalyst obtained is 0.82 g / cm 3 .

[0054] Example 8

[0055] The catalyst preparation method is the same as that in Example 1, except that the tableting pressure is adjusted to 75 KN. The bulk density of the catalyst obtained is 0.96 g / cm 3 .

[0056] Comparative Example 1

[0057] This comparative example provides a catalyst for producing 3,4-dihydro-2H-pyran using tetrahydrofurfuryl alcohol as a raw material and a preparation method thereof, which is basically the same as Example 1, except that no chromium oxide is added to the mixture A in step (1). Specifically, 80 kg of aluminum oxide, 15 kg of graphite, 0.35 kg of copper oxide, 0.035 kg of nickel oxide and 0.015 kg of cobalt oxide are mixed to obtain a mixture A.

[0058] Comparative Example 2

[0059] The present comparative example provides a catalyst for producing 3,4-dihydro-2H-pyran using tetrahydrofurfuryl alcohol as a raw material and a preparation method thereof. The raw materials and process parameters are substantially the same as those of Example 1, except that nickel oxide is not added to mixture A in step (1). Specifically, 80 kg of aluminum oxide, 15 kg of graphite, 4.6 kg of chromium oxide, 0.35 kg of copper oxide, and 0.015 kg of cobalt oxide are mixed to obtain mixture A.

[0060] Comparative Example 3

[0061] The present comparative example provides a catalyst for producing 3,4-dihydro-2H-pyran using tetrahydrofurfuryl alcohol as a raw material and a preparation method thereof. The raw materials and process parameters are substantially the same as those of Example 1, except that no cobalt oxide is added to the mixture A in step (1). Specifically, 80 kg of aluminum oxide, 15 kg of graphite, 4.6 kg of chromium oxide, 0.35 kg of copper oxide and 0.035 kg of nickel oxide are mixed to obtain a mixture A.

[0062] Comparative Example 4

[0063] The present comparative example provides a catalyst for producing 3,4-dihydro-2H-pyran using tetrahydrofurfuryl alcohol as a raw material and a preparation method thereof. The raw materials and process parameters are substantially the same as those of Example 1, except that no graphite is added to the mixture A in step (1). Specifically, 80 kg of aluminum oxide, 4.6 kg of chromium oxide, 0.35 kg of copper oxide, 0.035 kg of nickel oxide and 0.015 kg of cobalt oxide are mixed to obtain a mixture A.

[0064] The catalysts prepared in the examples and comparative examples were used as catalysts for producing 3,4-dihydro-2H-pyran from tetrahydrofurfuryl alcohol. The tetrahydrofurfuryl alcohol was fed into an evaporator at a feed rate of 550 kg / h. 3 / h rate of nitrogen to the system, the reaction temperature is 250-280 ℃ (initial temperature 250 ℃, gradually raised to 280 ℃ in the later stage of the reaction), pressure: 0.01-0.02MPa; tetrahydrofurfuryl alcohol to the catalyst space velocity is 1.2h -1 The nitrogen space velocity on the catalyst is 2.5h -1 The conversion rate, selectivity and unit consumption results after running for 2 hours and 120 days are shown in Table 1 below. Yield = Selectivity * Conversion rate.

[0065] Table 1 Results

[0066]

[0067] As can be seen from the above table, compared with Comparative Examples 1-4, the catalysts obtained in each embodiment of the present invention have good operating stability at high space velocity, significantly improved yield, and low catalyst unit consumption. Compared with Examples 4 and 5, Examples 1-3 further significantly reduce the catalyst unit consumption by controlling the chromium oxide content within the preferred range, and under the catalyst formulation and process conditions of Example 1, the product selectivity is the highest, the catalyst life is the longest, and the catalyst cost is the lowest, which is the optimal solution.

[0068] Obviously, the above embodiments are merely examples for the purpose of clear explanation, and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived therefrom are still within the scope of protection of the invention.

Claims

1. A catalyst for producing 3,4-dihydro-2H-pyran, characterized in that Taking the total mass of the catalyst as 100%, the catalyst comprises:

2. The catalyst for producing 3,4-dihydro-2H-pyran according to claim 1, characterized in that The catalyst contains 3.5-8% chromium oxide.

3. The catalyst for producing 3,4-dihydro-2H-pyran according to claim 1 or 2, characterized in that The bulk density of the catalyst is 0.6-1.6 g / cm 3 , preferably 0.75-1.1 g / cm 3 .

4. A method for preparing the catalyst according to any one of claims 1 to 3, characterized in that: The steps include: (1) mixing aluminum oxide, graphite, chromium oxide, copper oxide, nickel oxide and cobalt oxide to obtain a mixture A, adding a solvent, ball milling, drying, adding an alkali solution for activation, filtering, washing with water, and drying to obtain a mixture B; (2) Mix the mixture B with the binder, extrude and compress the mixture into tablets, sinter and dry the tablets to obtain the catalyst.

5. The preparation method according to claim 4, characterized in that: Step (1) satisfies at least one of the following AEs: A. The solvent is water; B. The mass ratio of mixture A to solvent is 50-80:300-500; C. Drying temperature is 160-200℃; D. The average particle size of the slurry after ball milling is 30-80 μm, preferably 40-60 μm; E. The tableting pressure is 60-80KN.

6. The preparation method according to claim 4 or 5, characterized in that: Step (1) satisfies at least one of the following 1)-6): 1) Adding an alkaline solution with a mass concentration of 5-10% for activation; 2) The ratio of the added mass of the alkaline solution to the mass of the mixture A is 5:1-3:1; and / or the alkaline substance contained in the alkaline solution is selected from one or more of potassium hydroxide, sodium hydroxide, sodium carbonate, and sodium bicarbonate; 3) The binder is selected from at least one of polyethylene, styrene, methyl silicone oil and silicone grease; 4) The mass ratio of mixture A to binder is 85-100:50-100; 5) The sintering temperature is 650-850°C and the sintering time is 4-8 hours; 6) Drying temperature is 160-200℃.

7. Use of the catalyst according to claim 1 or 2 or the catalyst prepared by the preparation method according to any one of claims 4 to 6 in the preparation of 3,4-dihydro-2H-pyran.

8. A method for producing 3,4-dihydro-2H-pyran, characterized in that: Tetrahydrofurfuryl alcohol is reacted in the presence of the catalyst described in claim 1 or 2 or the catalyst prepared by the preparation method described in any one of claims 4 to 6 to prepare 3,4-dihydro-2H-pyran; preferably, the reaction temperature is 250-300° C. and the pressure is 0-0.15 MPa.

9. The method for producing 3,4-dihydro-2H-pyran according to claim 8, characterized in that The space velocity of tetrahydrofurfuryl alcohol on the catalyst is 0.5-1.5h -1 , preferably 1.0-1.3h -1 .

10. The method for producing 3,4-dihydro-2H-pyran according to claim 8, characterized in that The nitrogen space velocity to the catalyst is 2-4h -1 , preferably 2.4-3.0h -1 .

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