Fuel precursor, preparation method thereof and fuel

Abstract

The invention provides a fuel precursor, a preparation method thereof and fuel. The preparation method of the fuel precursor comprises the following steps: mixing an acidic molecular sieve catalyst, a solvent and aromatic ester, and reacting in an inert atmosphere to obtain the fuel precursor, the structural formula of the aromatic ester is as shown in the formula (1): # imgabs0 # (1); wherein R1 comprises at least one of CxH2x + 1, CyH2y-1 and C6 + zH5 + z, x is greater than or equal to 1 and less than or equal to 9, y is greater than or equal to 2 and less than or equal to 9, and z is greater than or equal to 0 and less than or equal to 3; r2 comprises H and / or OCH3; and R3 comprises H and / or OCH3. The acidic molecular sieve is adopted as the catalyst, the activity of the catalyst for catalyzing the rearrangement reaction of aromatic ester is high, and the raw material conversion rate and the product yield are high; the catalyst is solid, is a heterogeneous catalyst and can be recycled, so that the production cost is greatly reduced, and the catalyst is non-corrosive to equipment.

Description

Technical Field

[0001] The present application relates to the field of chemical technology, and in particular to a fuel precursor and a preparation method thereof and a fuel. Background Art

[0002] Substances with hydroxyl and carbonyl substituents on the benzene ring have the properties of phenols and aromatic ketone compounds. They are important raw materials in organic synthesis and important intermediates in industries such as pharmaceuticals and perfume manufacturing. There are many methods for preparing aromatic ketones, such as Friedel-Crafts acylation, Fries rearrangement and diazotization. Among them, Fries rearrangement is the most commonly used method for synthesizing aromatic ketones and is also a synthetic route commonly used in industry. There are many kinds of catalysts currently used for Fries rearrangement, but the commonly used catalysts are homogeneous catalysts, which have the disadvantages of large catalyst dosage, strong corrosiveness, complex post-processing, rapid deactivation and non-reusability. Summary of the invention

[0003] In view of this, embodiments of the present application provide a fuel precursor, a preparation method thereof, and a fuel.

[0004] The first aspect of the present application provides a method for preparing a fuel precursor, comprising:

[0005] The acidic molecular sieve catalyst, solvent and aromatic ester are mixed and reacted under an inert atmosphere to obtain the fuel precursor;

[0006] The structural formula of the aromatic ester is shown in formula (1):

[0007]

[0008] Among them, R1 includes C x H 2x+1 , C y H 2y-1 and C 6+z H 5+2z At least one of, 1≤x≤9, 2≤y≤9, 0≤z≤3; R2 includes H and / or OCH3; R3 includes H and / or OCH3.

[0009] In one embodiment, the silicon-aluminum ratio of the acidic molecular sieve catalyst is 5-150, preferably 40-150.

[0010] In one embodiment, the acidic molecular sieve catalyst comprises a zeolite molecular sieve having at least one structure of BETA, FAU and MWW;

[0011] Preferably, the acidic molecular sieve catalyst includes at least one of Hβ, HX, HY, HUSY and MCM-22.

[0012] In one embodiment, the mass content of the acidic molecular sieve catalyst is 10-20 wt % of the mass of the aromatic ester.

[0013] In one embodiment, the solvent includes at least one of hexane, cyclohexane and n-heptane.

[0014] In one embodiment, the mass ratio of the aromatic ester to the solvent is 1 g:(10-20) g; preferably 1 g:(10-15) g.

[0015] In one embodiment, the inert atmosphere includes nitrogen and / or argon.

[0016] In one embodiment, the reaction temperature is 180-200° C. and the reaction time is 5-12 hours.

[0017] The second aspect of the present application provides a fuel precursor, which is prepared by the above-mentioned preparation method. The structural formula of the fuel precursor is shown in formula (2):

[0018]

[0019] Among them, R4 includes C x H 2x+1 , C y H 2y-1 and C 6+z H 5+2z At least one of, 1≤x≤9, 2≤y≤9, 0≤z≤3; R5 includes H and / or OCH3; R6 includes H and / or OCH3.

[0020] The third aspect of the present application provides a fuel prepared using the above-mentioned fuel precursor; the fuel comprises a structural formula as shown in formula (3) and / or formula (4):

[0021]

[0022] Wherein, R7 and R9 include H and / or CH3; R8 is C x H 2x+1 , 1≤x≤9.

[0023] According to the preparation method of the fuel precursor provided in the embodiment of the present application, an acidic molecular sieve is used as a catalyst, which has both B acid and L acid active centers, and the synergistic effect of the two can improve the catalyst activity. In addition, the acidic molecular sieve has different acid strength centers, which can reduce the degree of coking and carbon deposition. The raw material conversion rate and product yield of the rearrangement reaction catalyzed by the acidic molecular sieve catalyst are high; the catalyst is solid, non-corrosive to the equipment, can be recycled and reused, and the production cost is greatly reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a result diagram of aromatic ester conversion rate and fuel precursor selectivity of Example 4, Example 8, Example 14 and Comparative Examples 1 to 3. DETAILED DESCRIPTION

[0025] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0026] In addition, in order to better illustrate the present application, numerous specific details are given in the following specific embodiments. It should be understood by those skilled in the art that the present application can also be implemented without certain specific details. In some examples, methods and means well known to those skilled in the art are not described in detail in order to highlight the subject matter of the present application.

[0027] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0028] In addition, the terms “first”, “second”, etc., if used, are merely used to distinguish between the descriptions and should not be understood as indicating or implying relative importance.

[0029] The first aspect of the present application provides a method for preparing a fuel precursor, comprising:

[0030] The acidic molecular sieve catalyst, solvent and aromatic ester are mixed and reacted under an inert atmosphere to obtain the fuel precursor;

[0031] The structural formula of the aromatic ester is shown in formula (1):

[0032]

[0033] Among them, R1 includes C x H 2x+1 , C y H 2y-1 and C 6+z H 5+2z At least one of, 1≤x≤9, 2≤y≤9, 0≤z≤3; R2 includes H and / or OCH3; R3 includes H and / or OCH3.

[0034] According to the preparation method of the fuel precursor provided in the embodiment of the present application, an acidic molecular sieve is used as a catalyst, which has both B acid and L acid active centers, and the synergistic effect of the two can improve the catalyst activity. In addition, the acidic molecular sieve has different acid strength centers, which can reduce the degree of coking and carbon deposition. The raw material conversion rate and product yield of the rearrangement reaction catalyzed by the acidic molecular sieve catalyst are high; the catalyst is solid, non-corrosive to the equipment, can be recycled and reused, and the production cost is greatly reduced.

[0035] At present, some lignin can be depolymerized at high temperature in carboxylic acid solution to obtain rich aromatic ester substances. Using them as raw materials to prepare high-density fuels can significantly improve the economic value of lignin and promote the green development of aviation fuels. Compared with conventional homogeneous Br and L acid catalysts, acidic molecular sieves as catalysts have both Br and L acid active centers, which can reduce the degree of coking and carbon deposition. Taking the Br acid site of the molecular sieve as an example, the reaction mechanism for preparing the fuel precursor is as follows:

[0036]

[0037] The oxygen directly bonded to the benzene ring of the aromatic ester attacks the H on the catalyst surface with its lone pair of electrons. + The active center, the ester group breaks, and phenol and acyl carbon cation are generated (step (1)). Phenol and the acyl carbon cation on the catalyst surface are directly acylated (step (2)) to obtain ortho-aromatic ketone, para-aromatic ketone and H on the catalyst surface. + active center (step (3)); in addition, the acyl carbonium ion can also be directly connected to the aromatic ester to form an aromatic ketone compound containing an acyl group (step (4)).

[0038] In one embodiment, the silicon-aluminum ratio of the acidic molecular sieve catalyst is 5 to 150, for example, it can be 5, 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 110, 120, 130, 140 or 150. When the silicon-aluminum ratio of the acidic molecular sieve catalyst is less than 5, the medium-strong acid content of the molecular sieve is too low, and the selectivity of the aromatic ketone product is low; when the silicon-aluminum ratio of the acidic molecular sieve catalyst is greater than 150, the total acid content in the molecular sieve is too low, resulting in a low reactant conversion rate.

[0039] In a preferred embodiment, the silicon-aluminum ratio of the acidic molecular sieve catalyst is 40-150.

[0040] In one embodiment, the acidic molecular sieve catalyst includes a zeolite molecular sieve having at least one structure of BETA, FAU and MWW, BETA has a three-dimensional twelve-membered ring channel structure, FAU has a supercage structure and a three-dimensional twelve-membered ring channel structure, and MWW has a two-dimensional structure of ten-membered ring channels. All three zeolite molecular sieves can carry out macromolecular system reactions.

[0041] In one embodiment, the acidic molecular sieve catalyst includes at least one of Hβ, HX, HY, HUSY and MCM-22. Therefore, the acidic molecular sieve catalyst has excellent activity in catalyzing the rearrangement reaction of aromatic esters.

[0042] In one embodiment, based on the total mass of the acidic molecular sieve catalyst, the solvent and the aromatic ester, the mass content of the acidic molecular sieve catalyst is 10-20wt%. Relative to the above content, when the mass content of the acidic molecular sieve catalyst is less than 10wt%, too few acid active centers are provided and the conversion rate is less than 40%; when the mass content of the acidic molecular sieve catalyst is higher than 20wt%, the molecular mass transfer in the system is limited, resulting in a little improvement in the catalytic effect.

[0043] In one embodiment, the solvent includes at least one of hexane, cyclohexane and n-heptane.

[0044] In one embodiment, the mass ratio of the aromatic ester to the solvent is 1g:(10-20)g, for example, 1g:10g, 1g:12g, 1g:14g, 1g:16g, 1g:18g, 1g:20g, etc. Relative to the above mass ratio range, when the mass ratio of the aromatic ester to the solvent is greater than 1g:20g, the raw material concentration in the system is too low, and the conversion rate is reduced to less than 45%.

[0045] In a preferred embodiment, the mass ratio of the aromatic ester to the solvent is 1 g:(10-15) g.

[0046] In one embodiment, the inert atmosphere includes nitrogen and / or argon.

[0047] In one embodiment, the reaction temperature is 180-200°C, for example, 180°C, 185°C, 190°C or 200°C, etc.; the reaction time is 5-12h, for example, 5h, 7h, 9h, 11h or 12h, etc.

[0048] The second aspect of the present application provides a fuel precursor, which is prepared by the above-mentioned preparation method. The structural formula of the fuel precursor is shown in formula (2):

[0049]

[0050] Among them, R4 includes C x H 2x+1 , C y H 2y-1 and C 6+z H 5+2zAt least one of, 1≤x≤9, 2≤y≤9, 0≤z≤3; R5 includes H and / or OCH3; R6 includes H and / or OCH3.

[0051] The third aspect of the present application provides a fuel, which is prepared by using the above-mentioned fuel precursor. The fuel includes the structural formula shown in formula (3) and / or formula (4):

[0052]

[0053] Wherein, R7 and R9 include H and / or CH3; R8 is C x H 2x+1 , 1≤x≤9.

[0054] For example, the fuel of this embodiment can be obtained by hydrogenating the above fuel precursor. The operation process is as follows: 1g of aromatic ketone product, 1g of HZSM-5 molecular sieve and 0.1g of Pd / C are added to the reactor, 3MPa of H2 is filled in after replacing the air in the reactor, the temperature is raised to 200°C, and stirred at 600rpm for 8h.

[0055] The present application is further described below in conjunction with specific embodiments. It should be noted that the following embodiments are only used to explain the present application and are not to be construed as limiting the present application.

[0056] Example 1

[0057] The method for preparing the fuel precursor comprises the following steps:

[0058] (1) The molecular sieve is calcined at 550°C to remove the template. Weigh 1.0 g of phenyl hexanoate, 10 g of cyclohexane solvent, and 0.15 g of Hβ molecular sieve that has been activated by calcination; pour them into a batch reactor. Use nitrogen to replace the air in the reactor and then fill it with 0.5 MPa of nitrogen.

[0059] (2) Turn on magnetic stirring (600 rpm) and simultaneously start the temperature program to rise to 180° C. and react for 10 hours.

[0060] (3) Cooling to room temperature, separating and obtaining the fuel precursor product, and using gas chromatography-mass spectrometry and gas chromatography to conduct qualitative and quantitative analysis of the product, the feedstock conversion rate was 63.1%, and the selectivity of the fuel precursor was 76.8%.

[0061] Example 2-15

[0062] The preparation methods of the fuel precursors of Examples 2-15 and Comparative Examples 1 to 4 are basically the same as those of Example 1, except for the type of aromatic ester, the type and amount of acidic molecular sieve catalyst, the silicon-aluminum ratio of the acidic molecular sieve catalyst, the type and amount of solvent, and the reaction temperature or reaction time, as shown in Table 1 below. The selectivity of the fuel precursors of Examples 2-15 and the conversion rate of aromatic ester are also shown in Table 1 below.

[0063] Table 1

[0064]

[0065]

[0066] Comparative Example 1

[0067] The preparation method of the fuel precursor in this comparative example is basically the same as that in Example 4, except that the temperature is replaced with 140° C. In this comparative example, the substrate conversion rate is 26.7% and the product selectivity is 44.1%.

[0068] Comparative Example 2

[0069] The preparation method of the fuel precursor in this comparative example is basically the same as that in Example 8, except that the amount of the molecular sieve used is 4% of the amount of the raw material used. In this comparative example, the substrate conversion rate is 13.2% and the product selectivity is 35.9%.

[0070] Comparative Example 3

[0071] The preparation method of the fuel precursor in this comparative example is basically the same as that in Example 14, except that the zeolite molecular sieve is replaced by HZSM-5. In this comparative example, the substrate conversion rate is 17.9% and the product selectivity is 41.4%.

[0072] Comparative Example 4

[0073] The preparation method of the fuel precursor of Comparative Example 4 is basically the same as that of Example 1, except that the acidic molecular sieve catalyst is replaced by H2SO4.

[0074] The selectivity of the fuel precursor and the conversion rate of aromatic ester in Comparative Example 4 are shown in Table 2 below.

[0075] Table 2

[0076]

[0077] After the acidic molecular sieve catalyst of Example 1 was reused, the recovered acidic molecular sieve catalyst was used as a catalyst to prepare a fuel precursor according to the same preparation method as Example 1. The selectivity of the fuel precursor and the conversion rate of aromatic ester are shown in Table 3 below.

[0078] Table 3

[0079]

[0080] The catalyst H2SO4 in Comparative Example 4 cannot be recovered and causes serious corrosion to the equipment.

[0081] The basic principles of the present application are described above in conjunction with specific embodiments. However, it should be noted that the advantages, strengths, effects, etc. mentioned in the present application are only examples and not limitations, and it cannot be considered that these advantages, strengths, effects, etc. are required by each embodiment of the present application. In addition, the specific details disclosed above are only for the purpose of illustration and ease of understanding, not for limitation, and the above details do not limit the present application to being implemented by adopting the above specific details.

[0082] The above description has been given for the purpose of illustration and description. In addition, this description is not intended to limit the embodiments of the present application to the forms disclosed herein. Although multiple example aspects and embodiments have been discussed above, those skilled in the art will recognize certain variations, modifications, changes, additions and sub-combinations thereof.

Claims

1. A method for preparing a fuel precursor, characterized in that: include: The acidic molecular sieve catalyst, solvent and aromatic ester are mixed and reacted under an inert atmosphere to obtain the fuel precursor; The structural formula of the aromatic ester is shown in formula (1): Among them, R1 includes C x H 2x+1 , C y H 2y-1 and C 6+z H 5+2z At least one of, 1≤x≤9, 2≤y≤9, 0≤z≤3; R2 includes H and / or OCH3; R3 includes H and / or OCH3.

2. The preparation method according to claim 1, characterized in that: The silicon-to-aluminum ratio of the acidic molecular sieve catalyst is 5-150, preferably 40-150.

3. The preparation method according to claim 1 or 2, characterized in that: The acidic molecular sieve catalyst comprises a zeolite molecular sieve having at least one structure of BETA, FAU and MWW; Preferably, the acidic molecular sieve catalyst includes at least one of Hβ, HX, HY, HUSY and MCM-22.

4. The preparation method according to claim 1 or 2, characterized in that: The mass of the acidic molecular sieve catalyst is 10-20 wt% of the mass of the aromatic ester.

5. The preparation method according to claim 1, characterized in that: The solvent includes at least one of hexane, cyclohexane and n-heptane.

6. The preparation method according to claim 1 or 5, characterized in that: The mass ratio of the aromatic ester to the solvent is 1 g:(10-20) g, preferably 1 g:(10-15) g.

7. The preparation method according to claim 1, characterized in that: The inert atmosphere includes nitrogen and / or argon.

8. The preparation method according to claim 1, characterized in that: The reaction temperature is 180-200° C. and the reaction time is 5-12 hours.

9. A fuel precursor, characterized in that: It is prepared by the preparation method according to any one of claims 1 to 8, and the structural formula of the fuel precursor is shown in formula (2): Among them, R4 includes C x H 2x+1 , C y H 2y-1 and C 6+z H 5+2z At least one of, 1≤x≤9, 2≤y≤9, 0≤z≤3; R5 includes H and / or OCH3; R6 includes H and / or OCH3.

10. A fuel, characterized in that: It is prepared using the fuel precursor according to claim 9, and the fuel comprises the structural formula shown in formula (3) and / or formula (4): Wherein, R7 and R9 include H and / or CH3; R8 is C x H 2x+1 , 1≤x≤9.

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