CN113233953B

CN113233953B - Method for preparing 2, 6-di-tert-butyl naphthalene with high selectivity by naphthalene alkylation

Info

Publication number: CN113233953B
Application number: CN202110163212.1A
Authority: CN
Inventors: 戴立言; 蔡梦露; 王晓钟; 陈英奇
Original assignee: Zhejiang University ZJU
Current assignee: Zhejiang University ZJU
Priority date: 2021-02-05
Filing date: 2021-02-05
Publication date: 2022-11-18
Anticipated expiration: 2041-02-05
Also published as: CN113233953A

Abstract

The invention discloses a method for preparing 2, 6-di-tert-butylnaphthalene by high selectivity of naphthalene alkylation, which comprises the following steps: adding naphthalene, an alkylating reagent and a catalyst into an organic solvent, and reacting for 2-12h at the temperature of 120-240 ℃ and the initial pressure of 0-6 MPa; the catalyst comprises a carrier and metal elements loaded on the carrier, wherein the metal elements are zirconium and other metal elements, and the other metal elements are one or more of tungsten, aluminum, magnesium and cerium. The method has high naphthalene conversion rate, and the ratio of 2,6-/2,7-DTBN in the product is larger than most reported data. The method has the characteristics of mild operation conditions and high selectivity of target products.

Description

Method for preparing 2, 6-di-tert-butyl naphthalene with high selectivity by naphthalene alkylation

Technical Field

The invention belongs to the field of chemical engineering, and particularly relates to a method for preparing 2, 6-di-tert-butylnaphthalene by naphthalene alkylation.

Background

2, 6-dialkyl naphthalene is an important organic chemical raw material, and is a potential precursor of a novel polyester material polyethylene 2, 6-naphthalate (PEN). PEN is chemically stable, dimensionally stable, and has excellent properties in heat resistance, gas barrier properties, and stability, and thus the market demand is large.

The synthesis method of the 2, 6-dialkyl naphthalene mainly comprises three methods, wherein toluene is taken as a raw material, and the 2, 6-dialkyl naphthalene is obtained by four steps of acylation, hydrogenation, dehydration and dehydrocyclization under the joint participation of n-butene and carbon monoxide, and the method has a long process route and high production cost; taking xylene and 1-butene or 1, 3-butadiene as raw materials, carrying out an olefination reaction under the catalysis of alkali metal, and then carrying out dehydrocyclization and isomerization to obtain 2, 6-dialkyl naphthalene (WO 9702225), wherein the method is industrialized by Mitsubishi gas chemical company and Mitsubishi oil company; the method for obtaining the 2, 6-dialkyl naphthalene by alkylating naphthalene, isomerizing, separating and purifying is the most reasonable technical route at present, but the route adopts hydrofluoric acid, sulfuric acid and anhydrous aluminum trichloride as catalysts, has strong corrosivity and serious environmental pollution, and in addition, the method has the conditions of low conversion rate or difficult product separation caused by low ratio of the 2, 6-dialkyl naphthalene to the 2, 7-dialkyl naphthalene in actual production.

CN101417922A discloses a method for preparing 2, 6-di-tert-butyl naphthalene, which takes naphthalene as a raw material and tert-butyl as a substituent group, and prepares 2,6-DTBN on a Y-type zeolite molecular sieve through oxalic acid complexing modification, wherein the conversion rate of the naphthalene can reach 70 mol percent, and the ratio of 2,6-/2,7-DTBN is close to 9.0; CN105294385A discloses a method for preparing 2-methyl-6-tert-butylnaphthalene, which comprises using a phosphoric acid modified Y molecular sieve as a catalyst, firstly synthesizing 2-tert-butylnaphthalene, then catalyzing the alkylation of the 2-tert-butylnaphthalene with methanol by using a molecular sieve modified by a siloxane compound to obtain 2-methyl-6-tert-butylnaphthalene, and controlling the selectivity of the first step for preparing the 2-tert-butylnaphthalene so as to control the ratio of the last 2-methyl-6-tert-butylnaphthalene to the last 2-methyl-7-tert-butylnaphthalene; keith Smith et Al, through a series of studies on reaction time, reaction temperature, solvent, reaction pressure, amount of catalyst, and Si/Al ratio, disclose a method for producing 2, 6-di-tert-butylnaphthalene by alkylation of naphthalene with tert-butanol under MOR molecular sieve, and in this method, the ratio of 2,6-/2,7 can be as high as 50 (Org. Biomol. Chem.,2003,1, 1552); xuepi et al modified HY zeolite with cerium metal and found that the oxidation states of the different cerium on the catalyst had an effect on both the acid strength and acid concentration of the catalyst, thereby affecting the ratio of 2, 6-di-tert-butylnaphthalene to 2, 7-di-tert-butylnaphthalene (catal. Sci. Technol.,2017,7, 4700). In the report, although the conversion rate of naphthalene can reach more than 80%, the ratio of 2, 6-di-tert-butylnaphthalene to 2, 7-di-tert-butylnaphthalene is only between 6 and 8, and the industrial production has great separation difficulty.

Therefore, in the prior art, the improvement of the ratio of 2, 6-di-tert-butylnaphthalene to 2, 7-di-tert-butylnaphthalene is always the focus of research, and research for developing a high-efficiency alkylation catalyst and preparing 2, 6-di-tert-butylnaphthalene under relatively green and mild conditions is necessary.

Disclosure of Invention

The invention aims to overcome the problems of low ratio of 2, 6-di-tert-butylnaphthalene to 2, 7-di-tert-butylnaphthalene, low yield of target products, relatively complex operation, serious equipment corrosion and the like in the naphthalene alkylation process in the prior art, and provides a method for preparing 2, 6-di-tert-butylnaphthalene with high selectivity by naphthalene alkylation, which has the advantages of excellent naphthalene conversion rate, high ratio of 2, 6-di-tert-butylnaphthalene to 2, 7-di-tert-butylnaphthalene, simple operation, relatively green process and the like.

In order to achieve the above objects, the present invention provides a method for highly selectively producing 2, 6-di-tert-butylnaphthalene by naphthalene alkylation, the method comprising:

adding naphthalene, an alkylating reagent and a catalyst into an organic solvent, and reacting for 2-12h at the temperature of 120-240 ℃ and the initial pressure of 0-6 MPa; the catalyst comprises a carrier and metal elements loaded on the carrier, wherein the metal elements are zirconium and other metal elements, and the other metal elements are one or more of tungsten, aluminum, magnesium and cerium.

Preferably, the reaction temperature is 160 to 220 ℃ and the reaction pressure is 1 to 3MPa.

The alkylating agent is preferably tert-butyl alcohol, one or more of isobutene and isobutanol, and is further preferably tert-butyl alcohol.

The organic solvent is one or a mixture of more of dichloromethane, cyclohexane, normal hexane, mesitylene, 3, 4-dichlorotrifluorotoluene and decalin, and preferably the mesitylene.

The molar ratio of the zirconium to other metals in the catalyst is 1.2-1.2.

The total content of the metals is preferably 5 to 40 parts by weight, preferably 7 to 25 parts by weight, in terms of oxide, relative to 100 parts by weight of the carrier;

the carrier is a molecular sieve and/or a heat-resistant inorganic oxide, preferably a molecular sieve.

More preferably, the molecular sieve is at least one selected from the group consisting of MOR molecular sieve, MCM-22, MCM-41, and SBA-15.

According to the technical scheme, the 2, 6-di-tert-butylnaphthalene is prepared by the alkylation catalyst prepared by modifying organic acid, the organic acid is added to improve the overall acidity of the catalyst, and forms a metal compound with metal salt, the metal compound is added into a carrier, and then the carrier is decomposed in situ in the drying process and finally calcined to obtain the catalyst with high metal oxide dispersion. Compared with single metal, the double metal in the modified catalyst improves the selectivity of the 2, 6-di-tert-butyl naphthalene. The reaction process is mild, and the ratio of the 2, 6-di-tert-butylnaphthalene to the 2, 7-di-tert-butylnaphthalene in the product is larger than most reported data. Compared with the prior art, the method of the invention abandons the use of liquid acid and avoids the corrosion to equipment. The catalyst provided by the invention is a heterogeneous catalyst, is easy to recover and can be recycled, so that the production cost is reduced, and meanwhile, the catalyst has an industrial application prospect. The technology of the invention is also suitable for the reaction of other alkylating reagents and naphthalene, and can provide a new idea for preparing 2, 6-diisopropyl naphthalene, 2, 6-di-tert-amyl naphthalene and the like by the reaction of isopropanol, tert-amyl alcohol and naphthalene.

Drawings

FIG. 1 is a Mass Spectrum (MS) of 2, 6-di-tert-butylnaphthalene, a product obtained in example 1 of the present invention.

Detailed Description

The invention provides a method for preparing 2, 6-di-tert-butyl naphthalene with high selectivity by naphthalene alkylation, which comprises the following steps: adding naphthalene, an alkylating reagent and a catalyst into an organic solvent, and reacting for 2-12h at the temperature of 120-240 ℃ and the initial pressure of 0-6 MPa; the catalyst comprises a carrier and a metal element loaded on the carrier, wherein the metal element is the combination of zirconium and other metal elements, and the other metal elements are one or more of tungsten, aluminum, magnesium and cerium.

The alkylating agent is preferably tert-butyl alcohol, isobutene or isobutanol.

The organic solvent is one or a mixture of more of dichloromethane, cyclohexane, normal hexane, mesitylene, 3, 4-dichlorotrifluorotoluene and decalin.

The invention provides a novel preparation method for high-selectivity preparation of 2, 6-di-tert-butyl naphthalene by naphthalene alkylation. According to a preferred embodiment of the invention, the alkylating agent is tert-butanol and the solvent is mesitylene. In this preferred embodiment, the product is prepared such that the ratio of 2, 6-di-tert-butylnaphthalene to 2, 7-di-tert-butylnaphthalene is greater than 20.

In the invention, the molar ratio of zirconium to other metal elements in the catalyst is selected in a wide range, and the molar ratio of zirconium to other metal elements is 1;

the content of each component in the catalyst of the present invention is selected from a wide range, and preferably, the total content of the metals is 5 to 40 parts by weight, preferably 7 to 25 parts by weight, in terms of oxide, relative to 100 parts by weight of the carrier. Under the optimized condition, the loading amount of the active components in the catalyst enables the catalytic performance of the catalyst to be better.

In the present invention, the composition of the catalyst support may be conventional in the art, and according to the present invention, it is preferred that the support is a molecular sieve; further preferably, the molecular sieve is selected from at least one of MOR molecular sieve, MCM-22, MCM-41 and SBA-15.

In the present invention, the molecular sieve may be selected from commercially available molecular sieves and may also be selected from those prepared by any conventional method.

According to the present invention, preferably, the preparation method of the catalyst comprises:

(1) Dispersing zirconium salt, other metal salt and/or a modifier in water, stirring, then adding a carrier, stirring, evaporating excessive moisture, and drying the obtained solid to obtain a composite modified precursor;

(2) Sequentially grinding and calcining the composite modified precursor prepared in the step (1) to obtain the catalyst;

the zirconium salt is at least one of zirconium nitrate pentahydrate, zirconium oxychloride and zirconium acetate;

the other metal salt is at least one of nitrate, acetate or chloride;

the modifier is preferably an organic acid, preferably at least one of citric acid, tartaric acid, oxalic acid and boric acid;

the weight ratio of the metal salt, the modifier, the carrier and the water is preferably (1.0-2.0): (3.1-6.3): 6.8:80 to 102.

The organic acid modifier is preferably one or more of citric acid, tartaric acid, oxalic acid and boric acid, the organic acid is added to improve the overall acidity of the catalyst on one hand, and forms a metal compound with metal salt on the other hand, after the organic acid modifier is added to the carrier, the organic acid modifier is decomposed in situ in the drying process, and finally the catalyst with high dispersion of bimetallic oxides is obtained by calcination, so that the selectivity of the 2, 6-di-tert-butylnaphthalene is improved. More preferably, the organic acid is a dibasic organic carboxylic acid tartaric acid or a tribasic organic carboxylic acid citric acid, and still more preferably citric acid.

According to the preparation method provided by the invention, the alkylation catalyst is modified by organic acid, so that the overall acidity of the catalyst is improved, the reaction conversion rate is improved, and the selectivity of the 2, 6-di-tert-butyl naphthalene product is improved while the conversion rate is ensured by virtue of the synergistic effect of double metals, so that the high ratio of the 2, 6-di-tert-butyl naphthalene to the 2, 7-di-tert-butyl is ensured.

According to the preparation method provided by the invention, the mixing sequence in the step (1) is limited, specifically, the modifier is preferably added before the carrier and stirred to form the metal composite, and the mixing sequence of the zirconium salt and the organic acid modifier is not particularly limited.

The invention has wider selection range of the zirconium salt, and the zirconium salt is at least one of zirconium nitrate pentahydrate, zirconium oxychloride and zirconium acetate; the other metal salt is at least one of nitrate, acetate or chloride.

In the composite modified precursor, the total content of zirconium is 10-40 parts by weight, preferably 15-25 parts by weight calculated by oxide, relative to 100 parts by weight of the carrier; preferably, in the step (1), the stirring temperature is room temperature, the stirring time is 1-4 h, the temperature for evaporating excessive water is 60-90 ℃, and the drying temperature is 100-150 ℃; the calcining temperature in the step (2) is 400-700 ℃, and the calcining time is 5-10 h.

According to the present invention, the weight ratio of naphthalene to catalyst is preferably 2 to 15, more preferably 4 to 12.

According to the invention, it is preferred that the molar ratio between naphthalene, alkylating agent and organic solvent is 1: (1.0-4.0): (1 to 50), more preferably 1: (1.5-2.2): (1-20) so that the ratio of 2, 6-di-tert-butylnaphthalene to 2, 7-di-tert-butylnaphthalene is higher.

In the present invention, the stirring device is not particularly limited, and those skilled in the art can select the stirring device as needed according to actual needs. Specifically, a magnetic stirrer may be selected for the stirring, for example.

The drying equipment is not particularly limited in the present invention, and those skilled in the art can select the drying equipment according to actual needs. In particular, the drying may be performed, for example, in an oven.

In the present invention, the apparatus for the grinding is not particularly limited, and those skilled in the art can select the grinding apparatus as needed according to actual circumstances.

In the present invention, the equipment for performing the calcination is not particularly limited, and those skilled in the art can select the calcination according to actual needs. Specifically, for example, the firing may be performed in a muffle furnace.

The method for preparing 2, 6-di-tert-butyl naphthalene with high selectivity by naphthalene alkylation provided by the invention has the advantages of mild reaction process and simple product composition, and the ratio of the product 2, 6-di-tert-butyl naphthalene to the product 2, 7-di-tert-butyl naphthalene is greater than most reported data in the catalysis of the organic acid modified bimetallic catalyst, so that the method has obvious industrial application value.

The present invention will be described in detail below by way of examples.

Unless otherwise stated, room temperature means 25 ℃.

Example 1

First step catalyst preparation: 860mg of zirconium nitrate pentahydrate, 868mg of cerium nitrate pentahydrate and 920mg of citric acid were added to 15mL of deionized water at room temperature, stirred, and then 1g of MCM-22 molecular sieve was added. Stirring is continued for 2h, then the water is evaporated at 80 ℃, the mixture is dried for 24h at 100 ℃, the mixture is ground and calcined for 10h at 500 ℃, and the catalyst S1 is prepared.

The second step of catalytic alkylation reaction: and (2) taking the S1 molecular sieve catalyst (20 wt%,25 mg) and naphthalene (128 mg) obtained in the first step, adding 20mL of mesitylene as a solvent, adding tert-butyl alcohol (2.0 eq, 148mg) as an alkylating reagent, stirring at room temperature for 5min, fully mixing and activating, starting pressurizing to 2.0MPa, then carrying out temperature programming to 200 ℃ for reaction, wherein the total reaction time is 6h. The gas phase analysis showed that the naphthalene conversion was 40.5%, the selectivity for mono-substituted tert-butylnaphthalene in the product was 63.8%, the selectivity for di-substituted tert-butylnaphthalene in the product was 33.4%, and the 2,6-/2.7-DTBN was 14.90.

Comparative example 1

First step catalyst preparation: catalyst D1 was obtained in a similar manner to example 1, except that no metal salt other than the zirconium salt was added in step (1).

The second step of catalytic alkylation reaction: taking the D1 molecular sieve catalyst (20 wt%,25 mg) and naphthalene (128 mg) obtained in the first step, adding 20mL mesitylene as a solvent, adding tert-butyl alcohol (2.0 eq, 148mg) as an alkylating reagent, stirring at room temperature, fully mixing and activating, starting pressurizing to 2.0MPa, then raising the temperature to 200 ℃ by a program, and reacting for 6 hours. The gas phase analysis showed that the naphthalene conversion was 32.7%, the selectivity for mono-substituted tert-butylnaphthalene in the product was 9.9%, the selectivity for di-substituted tert-butylnaphthalene in the product was 90.1%, and the 2,6-/2.7-DTBN was 8.32.

Comparative example 2

The second step of catalytic alkylation reaction: similar conditions as in example 1 were followed to reduce the equivalent of t-butanol used as alkylating agent. Taking the D1 molecular sieve catalyst (12.6 wt%,65 mg) and naphthalene (512 mg) obtained in the first step, adding 20mL mesitylene as a solvent, adding tert-butyl alcohol (1.2eq, 355mg) as an alkylating reagent, stirring at room temperature, fully mixing and activating, starting pressurizing to 2.0MPa, then carrying out temperature programming to 200 ℃ for reaction, wherein the total reaction time is 6h. Gas phase analysis shows that the conversion rate of naphthalene is 15.5%, the selectivity of mono-substituted tert-butyl naphthalene in the product is 58.2%, the selectivity of di-substituted tert-butyl naphthalene in the product is 41.8%, and the selectivity of 2,6-/2.7-DTBN in the product is 8.32.

Example 2

First step catalyst preparation: 2575mg of zirconium nitrate pentahydrate, 1521mg of ammonium tungstate and 2300mg of citric acid were added to 60mL of deionized water at room temperature, stirred and then 5g of MOR molecular sieve was added. Stirring is continued for 2h, then water is evaporated at 80 ℃, drying is carried out for 24h at 100 ℃, grinding and calcining is carried out for 10h at 500 ℃, thus obtaining the catalyst S2.

The second step of catalytic alkylation reaction: taking the S2 molecular sieve catalyst (20 wt%,500 mg) obtained in the first step and naphthalene (2.56 g), adding 5mL mesitylene as a solvent, adding tert-butyl alcohol (2.0eq, 2.96g) as an alkylating reagent, stirring at room temperature, fully mixing and activating, starting pressurizing to 0MPa, then carrying out temperature programming to 180 ℃ for reaction, wherein the total reaction time is 6h. The gas phase analysis showed that the naphthalene conversion was 52.2%, the selectivity for mono-substituted tert-butylnaphthalene in the product was 62.2%, the selectivity for di-substituted tert-butylnaphthalene in the product was 36.5%, and the 2,6-/2.7-DTBN was 34.71.

Comparative example 3

First step catalyst preparation: catalyst D2 was obtained in a similar manner to example 2, except that no organic acid modifier, citric acid, was added in step (1).

The second step of catalytic alkylation reaction: taking the D2 molecular sieve catalyst (20 wt%,500 mg) obtained in the first step and naphthalene (2.56 g), adding 5mL mesitylene as a solvent, adding tert-butyl alcohol (2.0 eq, 2.96g) as an alkylating reagent, stirring at room temperature, fully mixing and activating, starting pressurizing to 0MPa, then carrying out temperature programming to 180 ℃ for reaction, wherein the total reaction time is 6h. The gas phase analysis showed that the naphthalene conversion was 38.2%, the selectivity for mono-substituted tert-butylnaphthalene in the product was 62.0%, the selectivity for di-substituted tert-butylnaphthalene in the product was 38.0%, and the 2,6-/2.7-DTBN was 65.67.

Example 3

First step catalyst preparation: 2575mg of zirconium nitrate pentahydrate, 1521mg of ammonium tungstate and 2300mg of citric acid were added to 60mL of deionized water at room temperature, stirred and then 5g of MOR molecular sieve was added. Stirring for 2h, evaporating water at 80 ℃, drying for 24h at 100 ℃, grinding, and calcining for 10h at 500 ℃ to obtain the catalyst S2.

The second step of catalytic alkylation reaction: the S2 molecular sieve catalyst obtained in the first step was taken, and the initial pressure was increased to 3.0MPa in a similar manner to example 2. The gas phase analysis showed that the naphthalene conversion was 81.4%, the selectivity for mono-substituted tert-butylnaphthalene in the product was 46.7%, the selectivity for di-substituted tert-butylnaphthalene in the product was 49.4%, and the 2,6-/2.7-DTBN was 22.26.

Example 4

First step catalyst preparation: 2575mg of zirconium nitrate pentahydrate, 750mg of aluminum nitrate nonahydrate and 770mg of citric acid were added to 60mL of deionized water at room temperature, stirred, and then 4g of SBA-15 molecular sieve was added. Stirring is continued for 2h, then water is evaporated at 80 ℃, dried for 4h at 100 ℃, ground and calcined for 5h at 650 ℃ to prepare the catalyst S3.

The second step of catalytic alkylation reaction: the S3 molecular sieve catalyst obtained in the first step was taken, and the reaction temperature was increased to 220 ℃ in a similar manner to example 2. Gas phase analysis shows that the conversion rate of naphthalene is 65.2%, the selectivity of mono-substituted tert-butyl naphthalene in the product is 65.2%, the selectivity of di-substituted tert-butyl naphthalene in the product is 29.3%, and the selectivity of 2,6-/2.7-DTBN in the product is 24.64.

Example 5

The second step of catalytic alkylation reaction: taking 10wt% of the S2 molecular sieve catalyst obtained in the first step (100 mg) and 1.024g of naphthalene, adding 15mL3, 4-dichlorotrifluorotoluene as a solvent, adding tert-butyl alcohol (2.0 eq, 1.184g) as an alkylating agent, stirring at room temperature, fully mixing and activating, starting pressurizing to 2.0MPa, then carrying out temperature programming to 160 ℃ for reaction, wherein the total reaction time is 8h. The gas phase analysis showed that the naphthalene conversion was 69.6%, the selectivity for mono-substituted tert-butylnaphthalene in the product was 32.7%, the selectivity for di-substituted tert-butylnaphthalene in the product was 67.3%, and the 2,6-/2.7-DTBN was 1.98.

Example 6

First step catalyst preparation: 2575mg of zirconium nitrate pentahydrate, 1521mg of ammonium tungstate and 2300mg of citric acid were added to 60mL of deionized water at room temperature, stirred and then 5g of MOR molecular sieve was added. Stirring is continued for 2h, then water is evaporated at 90 ℃, drying is carried out for 24h at 120 ℃, grinding and calcining is carried out for 6h at 500 ℃, thus obtaining the catalyst S4.

The second step of catalytic alkylation reaction: taking the S4 molecular sieve catalyst (40 wt%,500 mg) obtained in the first step and naphthalene (1.28 g), adding 10mL3, 4-dichlorotrifluorotoluene as a solvent, adding tert-butyl alcohol (2.0eq, 1.48g) as an alkylating reagent, stirring at room temperature, fully mixing and activating, starting pressurizing to 2.0MPa, and then carrying out temperature programming to 240 ℃ for reaction for 6 hours. Gas phase analysis shows that the conversion rate of naphthalene is 46.3%, the selectivity of mono-substituted tert-butyl naphthalene in the product is 72.5%, the selectivity of di-substituted tert-butyl naphthalene in the product is 27.5%, and the selectivity of 2,6-/2.7-DTBN in the product is 1.17.

Example 7

First step catalyst preparation: 1290mg of zirconium nitrate pentahydrate, 385mg of magnesium nitrate hexahydrate and 1122mg of citric acid were added to 20mL of deionized water at room temperature, stirred, and then 1.5g of MCM-22 molecular sieve was added. Stirring is continued for 2h, then water is evaporated at 70 ℃, drying is carried out for 8h at 110 ℃, grinding and calcining is carried out for 5h at 600 ℃, thus obtaining the catalyst S5.

The second step of catalytic alkylation reaction: taking the S5 molecular sieve catalyst (20 wt%,100 mg) and naphthalene (512 mg) obtained in the first step, adding 30mL mesitylene as a solvent, adding tert-butyl alcohol (1.2eq, 356 mg) as an alkylating reagent, stirring at room temperature, fully mixing and activating, starting pressurizing to 1.0MPa, then raising the temperature to 160 ℃ by a program, and reacting for 8 hours. Gas phase analysis shows that the conversion rate of naphthalene is 43.4%, the selectivity of mono-substituted tert-butyl naphthalene in the product is 54.0%, the selectivity of di-substituted tert-butyl naphthalene in the product is 21.7%, and the selectivity of 2,6-/2.7-DTBN in the product is 2.2.

Example 8

The second step of catalytic alkylation reaction: taking the S2 molecular sieve catalyst (40 wt%,500 mg) obtained in the first step and naphthalene (1.28 g), adding 6mL mesitylene as a solvent, adding tert-butyl alcohol (3.0eq, 2.22g) as an alkylating reagent, stirring at room temperature, fully mixing and activating, starting pressurizing to 2.0MPa, then carrying out temperature programming to 200 ℃ for reaction, wherein the total reaction time is 12h. The gas phase analysis showed that the naphthalene conversion was 85.8%, the selectivity for mono-substituted tert-butylnaphthalene in the product was 56.3%, the selectivity for di-substituted tert-butylnaphthalene in the product was 31.4%, and the 2,6-/2.7-DTBN was 6.69.

Example 9

First step catalyst preparation: 2575mg of zirconium nitrate pentahydrate, 1521mg of ammonium tungstate and 2300mg of citric acid were added to 60mL of deionized water at room temperature, stirred, and then 5g of MCM-41 molecular sieve was added. Stirring is continued for 2h, then water is evaporated at 60 ℃, drying is carried out for 8h at 120 ℃, grinding and calcining is carried out for 10h at 500 ℃, thus obtaining the catalyst S6.

The second step of catalytic alkylation reaction: taking the S6 molecular sieve catalyst (15.6 wt%,200 mg) and naphthalene (1.28 g) obtained in the first step, adding 20mL of 3, 4-dichlorotrifluorotoluene as a solvent, adding tert-butyl alcohol (2.0eq, 1.48g) as an alkylating reagent, stirring at room temperature, fully mixing and activating, starting pressurizing to 3.0MPa, then carrying out temperature programming to 200 ℃ for reaction, wherein the total reaction time is 6 hours. The gas phase analysis showed that the naphthalene conversion was 32.8%, the selectivity for mono-substituted tert-butylnaphthalene in the product was 76.5%, the selectivity for di-substituted tert-butylnaphthalene in the product was 23.5%, and the 2,6-/2.7-DTBN was 0.80.

Example 10

First step catalyst preparation: 2575mg of zirconium nitrate pentahydrate, 1521mg of ammonium tungstate and 2300mg of citric acid were added to 60mL of deionized water at room temperature, stirred, and then 5g of SBA-15 molecular sieve was added. Stirring is continued for 2h, then the water is evaporated at 80 ℃, the mixture is dried for 24h at 100 ℃, the mixture is ground and calcined for 10h at 500 ℃, and the catalyst S7 is prepared.

The second step of catalytic alkylation reaction: taking the S7 molecular sieve catalyst (20 wt%,500 mg) obtained in the first step and naphthalene (2.56 g), adding 20mL of dichloromethane as a solvent, adding tert-butyl alcohol (2.0 eq, 2.96g) as an alkylating reagent, stirring at room temperature, fully mixing and activating, starting pressurizing to 2.0MPa, then carrying out temperature programming to 120 ℃ for reaction, wherein the total reaction time is 6h. The gas phase analysis showed 1.6% conversion of naphthalene and 5.0% conversion of 2, 6-/2.7-DTBN.

Example 11

First step catalyst preparation: 2575mg of zirconium nitrate pentahydrate, 1230mg of magnesium nitrate hexahydrate and 2280mg of citric acid were added to 60mL of deionized water at room temperature, stirred and then 5g of MOR molecular sieve was added. Stirring is continued for 2h, then water is evaporated at 80 ℃, drying is carried out for 24h at 150 ℃, grinding and calcining is carried out for 10h at 400 ℃, thus obtaining the catalyst S8.

The second step of catalytic alkylation reaction: taking the S8 molecular sieve catalyst (20 wt%,500 mg) obtained in the first step and naphthalene (2.56 g), adding 50mL of cyclohexane as a solvent, adding tert-butyl alcohol (2.0 eq, 2.96g) as an alkylating reagent, stirring at room temperature, fully mixing and activating, starting pressurizing to 2.0MPa, then raising the temperature to 170 ℃ by program, and reacting for 12h. The gas phase analysis showed that the naphthalene conversion was 17.2%, the selectivity for mono-substituted tert-butylnaphthalene in the product was 59.8%, the selectivity for di-substituted tert-butylnaphthalene in the product was 40.2%, and the 2,6-/2.7-DTBN was 1.63.

Example 12

The second step of catalytic alkylation reaction: taking the S2 molecular sieve catalyst (40 wt%,500 mg) obtained in the first step and naphthalene (1.28 g), adding 6mL of n-hexane as a solvent, adding isobutene (3.0eq, 1.68g) as an alkylating reagent, stirring at room temperature, fully mixing and activating, starting pressurizing to 2.0MPa, then carrying out temperature programming to 220 ℃ for reaction, wherein the total reaction time is 12h. The gas phase analysis showed that the naphthalene conversion was 15.2%, the selectivity for mono-substituted tert-butylnaphthalene in the product was 62.6%, the selectivity for di-substituted tert-butylnaphthalene in the product was 37.4%, and the 2,6-/2.7-DTBN was 5.2.

Example 13

First step catalyst preparation: 655mg of zirconium acetate, 1521mg of ammonium tungstate and 2300mg of citric acid were added to 60mL of deionized water at room temperature, stirred, and then 5g of MOR molecular sieve was added. Stirring is continued for 2h, then water is evaporated at 80 ℃, drying is carried out for 12h at 120 ℃, grinding and calcining is carried out for 6h at 600 ℃, thus obtaining the catalyst S9.

The second step of catalytic alkylation reaction: taking the S9 molecular sieve catalyst (20 wt%,500 mg) obtained in the first step and naphthalene (2.56 g), adding 15mL mesitylene as a solvent, adding tert-butyl alcohol (2.0eq, 2.96g) as an alkylating reagent, stirring at room temperature, fully mixing and activating, starting pressurizing to 2.0MPa, then carrying out temperature programming to 140 ℃ for reaction, wherein the total reaction time is 6h. Gas phase analysis shows that the conversion rate of naphthalene is 27.5%, the selectivity of mono-substituted tert-butyl naphthalene in the product is 89.8%, the selectivity of di-substituted tert-butyl naphthalene in the product is 10.2%, and the selectivity of 2,6-/2.7-DTBN in the product is 2.21.

The preferred embodiments of the present invention have been described above in detail, but the present invention is not limited thereto. Within the scope of the technical idea of the invention, many simple modifications can be made to the technical solution of the invention, including combinations of various technical features in any other suitable manner, and these simple modifications and combinations should also be regarded as the disclosure of the invention, and all fall within the scope of the invention.

Claims

1. A method for preparing 2, 6-di-tert-butyl naphthalene with high selectivity by naphthalene alkylation is characterized by comprising the following steps:

first step catalyst preparation: adding 860mg of zirconium nitrate pentahydrate, 868mg of cerium nitrate pentahydrate and 920mg of citric acid into 15mL of deionized water at room temperature, stirring, then adding 1g of MCM-22 molecular sieve, continuing stirring for 2 hours, then evaporating water at 80 ℃, drying for 24 hours at 100 ℃, grinding, and calcining for 10 hours at 500 ℃ to obtain a catalyst S1;

the second step of catalytic alkylation reaction: taking 25mg of the S1 molecular sieve catalyst obtained in the first step and 128mg of naphthalene, adding 20mL of mesitylene as a solvent, adding 148mg of tert-butyl alcohol as an alkylating agent, stirring for 5min at room temperature, fully mixing and activating, starting pressurizing to 2.0MPa, then carrying out temperature programming to 200 ℃ for reaction, wherein the total reaction time is 6h, and the gas phase analysis shows that the conversion rate of the naphthalene is 40.5%, the selectivity of mono-substituted tert-butyl naphthalene in the product is 63.8%, the selectivity of di-substituted tert-butyl naphthalene in the product is 33.4%, and the selectivity of 2, 6-di-tert-butyl naphthalene/2, 7-di-tert-butyl naphthalene is 14.90%.

2. A method for preparing 2, 6-di-tert-butyl naphthalene with high selectivity by naphthalene alkylation is characterized by comprising the following steps:

first step catalyst preparation: adding 2575mg of zirconium nitrate pentahydrate, 1521mg of ammonium tungstate and 2300mg of citric acid into 60mL of deionized water at room temperature, stirring, then adding 5g of MOR molecular sieve, continuing stirring for 2h, then evaporating water at 80 ℃, drying for 24h at 100 ℃, grinding, and calcining for 10h at 500 ℃ to obtain a catalyst S2;

the second step of catalytic alkylation reaction: taking 500mg of the S2 molecular sieve catalyst obtained in the first step and 2.56g of naphthalene, adding 5mL of mesitylene as a solvent, adding 2.96g of tert-butyl alcohol as an alkylating reagent, stirring at room temperature, fully mixing and activating, starting pressurizing to 0MPa, then carrying out temperature programming to 180 ℃ for reaction, wherein the total reaction time is 6h, and the gas phase analysis shows that the conversion rate of the naphthalene is 52.2%, the selectivity of mono-substituted tert-butyl naphthalene in the product is 62.2%, the selectivity of di-substituted tert-butyl naphthalene in the product is 36.5%, and the selectivity of 2, 6-di-tert-butyl naphthalene/2, 7-di-tert-butyl naphthalene is 34.71.

3. A method for preparing 2, 6-di-tert-butyl naphthalene with high selectivity by naphthalene alkylation is characterized by comprising the following steps:

the second step of catalytic alkylation reaction: taking 500mg of the S2 molecular sieve catalyst obtained in the first step and 2.56g of naphthalene, adding 5mL of mesitylene as a solvent, adding 2.96g of tert-butyl alcohol as an alkylating reagent, stirring at room temperature, fully mixing and activating, starting pressurizing to 3.0MPa, then carrying out temperature programming to 180 ℃ for reaction, wherein the total reaction time is 6h, and the gas phase analysis shows that the conversion rate of naphthalene is 81.4%, the selectivity of mono-substituted tert-butyl naphthalene in the product is 46.7%, the selectivity of di-substituted tert-butyl naphthalene in the product is 49.4%, and the selectivity of 2, 6-di-tert-butyl naphthalene/2, 7-di-tert-butyl naphthalene is 22.26.

4. A method for preparing 2, 6-di-tert-butyl naphthalene with high selectivity by naphthalene alkylation is characterized by comprising the following steps:

first step catalyst preparation: adding 2575mg of zirconium nitrate pentahydrate, 750mg of aluminum nitrate nonahydrate and 770mg of citric acid into 60mL of deionized water at room temperature, stirring, then adding 4g of SBA-15 molecular sieve, continuing stirring for 2h, then evaporating water at 80 ℃, drying for 4h at 100 ℃, grinding, and calcining for 5h at 650 ℃ to obtain a catalyst S3;

the second step of catalytic alkylation reaction: taking 500mg of the S3 molecular sieve catalyst obtained in the first step and 2.56g of naphthalene, adding 5mL of mesitylene as a solvent, adding 2.96g of tert-butyl alcohol as an alkylating reagent, stirring at room temperature, fully mixing and activating, starting pressurizing to 0MPa, then carrying out temperature programming to 220 ℃ for reaction, wherein the total reaction time is 6h, and the gas phase analysis shows that the conversion rate of the naphthalene is 65.2%, the selectivity of mono-substituted tert-butyl naphthalene in the product is 65.2%, the selectivity of di-substituted tert-butyl naphthalene in the product is 29.3%, and the selectivity of 2, 6-di-tert-butyl naphthalene/2, 7-di-tert-butyl naphthalene is 24.64%.