A method for preparing a high-molybdenum-content molybdenum octoate catalyst by a bubbling method

Abstract

This invention discloses a method for preparing molybdenum isooctanoate catalyst with high molybdenum content using a bubbling process. The method employs nitrogen bubbling and hydrogen reduction techniques. Nitrogen bubbling rapidly removes water vapor and acetic acid generated during dehydration from the reaction system, which is more efficient and stable than static heating or slow vacuuming. It also aids in mixing, ensuring more thorough contact of reactants and inhibiting excessive aggregation of molybdenum species. Nitrogen bubbling provides an inert environment, maintaining the stability of the reaction system. Hydrogen reduction effectively suppresses acetylation side reactions and precipitation formation, and precisely guides the formation of highly dispersed dimer or oligomer structures. The molybdenum isooctanoate catalyst prepared by this process exhibits high stability, high dispersibility, and high molybdenum content.

Description

Technical Field

[0001] This invention relates to the field of catalytic materials technology, specifically to a method for preparing molybdenum isooctanoate catalysts with high molybdenum content using a bubbling method. Background Technology

[0002] Molybdenum isooctanoate is an oil-soluble organic molybdenum compound that combines with a unique tetranuclear molybdenum cluster through organic ligands to construct a novel multifunctional material that performs excellently in processes such as catalytic slurry bed residue hydrocracking, waste oil hydrotreating, and oil shale hydrotreating.

[0003] The preparation of molybdenum isooctanoate, such as the preparation method of oil-soluble molybdenum isooctanoate catalyst disclosed in CN118022832A, has the drawback of high reaction temperature and low molybdenum content. Other preparation processes of molybdenum isooctanoate also have disadvantages such as poor product stability and easy precipitation, which need to be improved. Summary of the Invention

[0004] To address at least one of the aforementioned technical deficiencies, the present invention provides the following technical solution:

[0005] This application discloses a method for preparing a high-molybdenum-content molybdenum isooctanoate catalyst by a bubbling process, comprising the following steps: First, preparation of activated molybdenum intermediates The molybdenum source is mixed with acid anhydride to generate an activated molybdenum intermediate. The molar ratio of molybdenum atoms to acid anhydride is 1:2-3.5. Nitrogen gas is introduced during the reaction and released from the surface of the mixture by bubbling to create an inert environment. Second, ligand exchange Isooctanoic acid was added under continuous bubbling of nitrogen to carry out a metathesis reaction, with a molar ratio of molybdenum atoms to isooctanoic acid of 1:2-4.5. Third, hydrogen reduction treatment Hydrogen gas is introduced into the reaction solution formed in the second step to carry out the reduction reaction.

[0006] Furthermore, the nitrogen flow rate during bubbling in the first and second steps is 20-35 ml / min. In the second step, bubbling is performed while vacuum distillation is carried out to remove the byproduct acetic acid.

[0007] Furthermore, in the third step, hydrogen and nitrogen are mixed and input, with a hydrogen content of 3-10%. This can be achieved by directly switching the gas source and using the tube that input nitrogen in the second step to mix and input hydrogen and nitrogen. Alternatively, hydrogen can be input through other tubes, and nitrogen can be input in conjunction with the tube that input nitrogen in the second step, as long as the hydrogen content ratio is met.

[0008] Furthermore, in the third step, the hydrogen input flow rate is 20-35 ml / min.

[0009] Furthermore, in the third step, the pH value of the reaction solution is detected before hydrogen is introduced, and hydrogen is introduced when the pH value is between 5 and 7.

[0010] Furthermore, the molybdenum source is one or more of molybdic acid, sodium molybdate, molybdenum phosphate, and molybdenum trioxide, and the acid anhydride is one or more of acetic anhydride, propionic anhydride, and acetic-propionic anhydride.

[0011] Furthermore, in the first step, the reaction temperature is 60-90℃ and the reaction time is 0.5-1.5h; in the second step, the reaction temperature is 100-130℃ and the reaction time is 1-3h; in the third step, the reaction temperature is 120-130℃ and the reaction time is 4h.

[0012] Compared with the prior art, the beneficial effects of the present invention are as follows: (1) Nitrogen bubbling, as a continuous physical carrying process, rapidly carries the water vapor and acetic acid generated by the dehydration reaction out of the reaction system. It is more efficient and stable than static heating or slow vacuuming. In addition, nitrogen bubbling also plays an auxiliary role in mixing, making the reactants more fully contacted and the reaction more uniform, and can inhibit the excessive aggregation of molybdenum species.

[0013] (2) Nitrogen bubbling provides an inert environment, forming an inert gas protective layer above the reaction liquid, eliminating interference from air (oxygen), preventing reactants or intermediates from being oxidized, and maintaining the stability of the reaction system.

[0014] (3) Hydrogen reduction treatment can eliminate the need for excess acid anhydride during the reaction process, thereby effectively suppressing acetylation side reactions and precipitation formation, and precisely guiding the formation of highly dispersed dimer or oligomer structures.

[0015] (4) The molybdenum isooctanoate catalyst prepared by this process has the characteristics of high stability, high dispersibility and high molybdenum content. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 The image shows the final product obtained from the process of preparing molybdenum isooctanoate in Example 1.

[0018] Figure 2 The infrared spectrum of molybdenum isooctanoate prepared in Example 8 is shown.

[0019] Figure 3 This is a TEM image of molybdenum isooctanoate prepared in Example 8. Detailed Implementation

[0020] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0021] Example 1 A method for preparing a high-molybdenum-content molybdenum isooctanoate catalyst by bubbling includes the following steps: First, preparation of activated molybdenum intermediates 45.53 g of molybdic acid and 57.40 g of acetic anhydride (molar ratio of molybdenum atoms to acetic anhydride was 1:2) were added to a container. The oil bath temperature was controlled at 80℃ and the reaction was carried out under magnetic stirring at 300 rpm for 1.5 hours to obtain an activated molybdenum intermediate. During the reaction, the outlet of the tube that introduced nitrogen gas was placed in the mixture of molybdic acid and acetic anhydride. The nitrogen gas output from the tube outlet was released from the surface of the mixture in a bubbling manner, and the released nitrogen gas created an inert environment in the container.

[0022] Second, ligand exchange Under continuous bubbling of nitrogen, 101.35 g of isooctanoic acid was added to the container from the first step to carry out a metathesis reaction. The molar ratio of molybdenum atoms to isooctanoic acid was controlled at 1:2.5. The reaction temperature was increased to 120°C, and vacuum distillation (-0.08 MPa) was carried out while bubbling to remove the byproduct acetic acid. The reaction was carried out at 200 rpm for 2 hours.

[0023] Third, hydrogen reduction treatment The pH value of the reaction solution was measured and stabilized at 6. Hydrogen gas was then introduced into the reaction solution of the second step to carry out the reduction reaction. At the same time, the vacuum device was stopped. Hydrogen gas was introduced through the original nitrogen gas tube and a hydrogen-nitrogen mixture was used. The hydrogen content was 6% by mass and the hydrogen flow rate was 20 mL / min. The reaction was stopped after 4 hours at 130℃.

[0024] The gaseous impurities generated during the reaction are expelled with the gas flow. For details on the preparation of molybdenum isooctanoate, please refer to [link to details]. Figure 1 .

[0025] Example 2 The difference from Example 1 is that the molybdenum source is 57.89g of sodium molybdate.

[0026] Example 3 The difference from Example 1 is that the molybdenum source is 42.76g of molybdenum phosphate.

[0027] Example 4 The difference from Example 1 is that the molybdenum source is 40.47g of molybdenum trioxide.

[0028] Example 5 The difference from Example 1 is that the acid anhydride is 73.17g of propionic anhydride.

[0029] Example 6 The difference from Example 1 is that the acid anhydride is 65.28g of acetic acid propionic anhydride.

[0030] Example 7 The difference from Example 1 is that the acid anhydride is 80.04g of butyric anhydride.

[0031] Example 8 The difference from Example 1 is that the molar ratio of molybdenum atoms to isooctanoic acid is changed to 1:3, and the metathesis reaction time is 3 hours. The infrared spectrum of the prepared molybdenum isooctanoate is detailed in [link to example]. Figure 2 See TEM images for details. Figure 3 .

[0032] Example 9 The difference from Example 1 is that the molar ratio of molybdenum atoms to acetic anhydride is 1:3, and the nitrogen flow rate is 30 mL / min.

[0033] Example 10 The difference from Example 1 is that the molar ratio of molybdenum atoms to acetic anhydride is 1:3.5, and the nitrogen flow rate is 35 mL / min.

[0034] Example 11 The difference from Example 1 is that the molar ratio of molybdenum atoms to acetic anhydride is 1:3, the nitrogen flow rate is 30 mL / min, the molar ratio of molybdenum atoms to isooctanoic acid is 1:3, and the metathesis reaction time is 3 hours.

[0035] Comparative Example 1 The difference from Example 1 is that nitrogen was not used for bubbling; instead, nitrogen was introduced from above the mixture of molybdic acid and acetic anhydride.

[0036] Comparative Example 2 The difference from Example 1 is that there is no hydrogen reduction process.

[0037] The properties of the molybdenum isooctanoate prepared in the above examples and comparative examples were tested. The molybdenum content was determined by inductively coupled plasma atomic emission spectrometry (ICP-OES); the dynamic viscosity was determined by a kinematic viscometer; the moisture content was determined by a Karl Fischer moisture analyzer; the acid value was determined by potentiometric titration; and the similarity was measured by the matching rate between the standard spectrum in the infrared spectral library and the prepared molybdenum isooctanoate, as detailed in Tables 1 and 2.

[0038] Table 1

[0039] Table 2

[0040] Table 3

[0041] The data in Tables 1 and 2 show that when molybdic acid or sodium molybdate is used as the molybdenum source and acetic anhydride as the acid anhydride, under the specified material ratio, the resulting molybdenum isooctanoate has the best molybdenum content. Other properties, such as dynamic viscosity and acid value, also exhibit excellent performance. Figure 1 As shown, the obtained molybdenum isooctanoate catalyst exhibits good stability and no solidification phenomenon.

[0042] The data in Table 3 show that when nitrogen is introduced in a non-bubbling manner or when hydrogen reduction is lacking, the molybdenum content in the obtained molybdenum isooctanoate catalyst is significantly reduced.

[0043] The above are merely preferred embodiments of the present invention. The scope of protection of the present invention is not limited to the above embodiments. All technical solutions falling within the scope of the present invention's concept are within the scope of protection of the present invention. It should be noted that for those skilled in the art, any improvements and modifications made without departing from the principle of the present invention should also be considered within the scope of protection of the present invention.

Claims

1. A process for the production of a high molybdenum content molybdenum octoate catalyst by a bubble process, characterized in that, Includes the following steps: First, preparation of activated molybdenum intermediates The molybdenum source is mixed with acid anhydride to generate an activated molybdenum intermediate. The molar ratio of molybdenum atoms to acid anhydride is 1:2-3.

5. Nitrogen gas is introduced during the reaction and released from the surface of the mixture by bubbling to create an inert environment. Second, ligand exchange Isooctanoic acid was added under continuous bubbling of nitrogen to carry out a metathesis reaction, with a molar ratio of molybdenum atoms to isooctanoic acid of 1:2-4.

5. Third, hydrogen reduction treatment Hydrogen gas is introduced into the reaction solution formed in the second step to carry out the reduction reaction.

2. The method for preparing high-molybdenum-content molybdenum isooctanoate catalyst by bubbling as described in claim 1, characterized in that: The nitrogen flow rate during bubbling in the first and second steps is 20-35 ml / min, with the second step involving simultaneous bubbling and vacuum distillation.

3. The method for preparing high-molybdenum-content molybdenum isooctanoate catalyst by bubbling as described in claim 1, characterized in that: The hydrogen content in the third step is 3-10%.

4. The method for preparing high-molybdenum-content molybdenum isooctanoate catalyst by bubbling as described in claim 1, characterized in that: In the third step, the hydrogen input flow rate is 20-35 ml / min.

5. The method for preparing a high-molybdenum-content molybdenum isooctanoate catalyst by bubbling as described in claim 1, characterized in that: In the third step, the pH value of the reaction solution is checked before hydrogen is introduced. When the pH value is between 5 and 7, hydrogen is introduced.

6. The method for preparing high-molybdenum-content molybdenum isooctanoate catalyst by bubbling as described in claim 1, characterized in that: The molybdenum source is one or more of molybdic acid, sodium molybdate, molybdenum phosphate, and molybdenum trioxide, and the acid anhydride is one or more of acetic anhydride, propionic anhydride, and acetic-propionic anhydride.

7. The method for preparing high-molybdenum-content molybdenum isooctanoate catalyst by bubbling as described in claim 1, characterized in that: In the first step, the reaction temperature is 60-90℃ and the reaction time is 0.5-1.5h; in the second step, the reaction temperature is 100-130℃ and the reaction time is 1-3h; in the third step, the reaction temperature is 120-130℃ and the reaction time is 4h.

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