CN114539014A - Method for preparing 2, 6-dimethylnaphthalene with high selectivity by naphthalene catalytic methylation - Google Patents

Method for preparing 2, 6-dimethylnaphthalene with high selectivity by naphthalene catalytic methylation Download PDF

Info

Publication number
CN114539014A
CN114539014A CN202210066483.XA CN202210066483A CN114539014A CN 114539014 A CN114539014 A CN 114539014A CN 202210066483 A CN202210066483 A CN 202210066483A CN 114539014 A CN114539014 A CN 114539014A
Authority
CN
China
Prior art keywords
catalyst
dimethylnaphthalene
stirring
naphthalene
reaction
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
CN202210066483.XA
Other languages
Chinese (zh)
Inventor
戴立言
张小广
王晓钟
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Zhejiang University ZJU
Original Assignee
Zhejiang University ZJU
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Zhejiang University ZJU filed Critical Zhejiang University ZJU
Priority to CN202210066483.XA priority Critical patent/CN114539014A/en
Publication of CN114539014A publication Critical patent/CN114539014A/en
Pending legal-status Critical Current

Links

Classifications

    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C2/00—Preparation of hydrocarbons from hydrocarbons containing a smaller number of carbon atoms
    • C07C2/86—Preparation of hydrocarbons from hydrocarbons containing a smaller number of carbon atoms by condensation between a hydrocarbon and a non-hydrocarbon
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J29/00—Catalysts comprising molecular sieves
    • B01J29/82—Phosphates
    • B01J29/84—Aluminophosphates containing other elements, e.g. metals, boron
    • B01J29/85—Silicoaluminophosphates (SAPO compounds)
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P20/00—Technologies relating to chemical industry
    • Y02P20/50—Improvements relating to the production of bulk chemicals
    • Y02P20/584—Recycling of catalysts

Abstract

The invention discloses a method for preparing 2, 6-dimethylnaphthalene with high selectivity by naphthalene catalytic methylation, which comprises the following steps: adding naphthalene, an alkylating agent and a catalyst into an organic solvent, and reacting for 1-2 hours at 350-450 ℃ under normal pressure; the catalyst is obtained by adding a phosphorus source, an aluminum source, a silicon source, a template agent and active metal salt into water, uniformly mixing, and crystallizing by a hydrothermal synthesis method, wherein the active metal is one or more of zirconium, zinc, cobalt, vanadium, chromium, tungsten, molybdenum, cerium and bismuth. The selectivity of the target product of the method is high, the selectivity of the product 2, 6-dimethylnaphthalene is up to 90%, the yield can reach 46% at most, and the method is far higher than the prior art reports in the field. The method has the characteristics of simple operation process and high selectivity of the target product.

Description

Method for preparing 2, 6-dimethylnaphthalene with high selectivity by naphthalene catalytic methylation
Technical Field
The invention belongs to the field of chemistry and chemical engineering, and particularly relates to a method for preparing 2, 6-dimethylnaphthalene with high selectivity by naphthalene catalytic methylation.
Background
2, 6-dimethylnaphthalene (2,6-DMN) is an important chemical intermediate, and polyethylene naphthalate (PEN) with high commercial value can be obtained by polymerizing the oxidized 2, 6-dimethylnaphthalene and ethylene glycol. PEN has good physical and mechanical properties, heat resistance, gas barrier property, ultraviolet radiation resistance and the like, can be used for manufacturing ultrathin video tapes, F-grade insulating films, food hot-filling bottles, medicine packaging films, high-temperature heat-resistant wires and the like, and has huge demand in the market.
The synthesis method of 2, 6-dimethylnaphthalene mainly comprises the following steps: extracting 2, 6-dimethylnaphthalene from each fraction of petroleum by means of distillation, extraction, crystallization, adsorption and the like; however, the content of 2,6-DMN in the process is low, the processing amount of raw materials is large, and the process is complicated. Using methylnaphthalene as a raw material, and carrying out transfer alkylation under the catalysis of a Lewis acid solid catalyst or a molecular sieve to synthesize 2, 6-dimethylnaphthalene; however, the process has high raw material cost, and disproportionation reaction is easy to occur between the product and the reactant, so that the purity of the target product is low, and the yield is reduced. The method also takes naphthalene as a raw material, and obtains the target product 2, 6-dimethylnaphthalene by carrying out methylation reaction with methanol and then carrying out molecular rearrangement, the engineering technology is relatively mature, the route is simple, the raw material source is rich, the price is low, the raw material can be fully utilized, the method is beneficial to reducing the manufacturing cost of the 2, 6-dialkylnaphthalene, and the method is a hotspot in the current industrial research field; however, the selectivity and the conversion rate of the currently widely used molecular sieve type shape-selective catalyst to a target product are low, the final yield is kept at a low level, and the application of mass production and industrialization cannot be realized, and meanwhile, 2, 6-dimethylnaphthalene and 2, 7-dimethylnaphthalene in the product have close boiling points and are difficult to separate, so that the purity of the target product is greatly influenced.
In recent years, the aluminum phosphate series molecular sieves show higher catalytic activity and selectivity in the preparation of 2, 6-dimethylnaphthalene through the methylation reaction of naphthalene and methanol, have good thermal stability and are suitable for alkylation reaction at high temperature. In addition, hetero atoms are introduced to replace Al or P atoms in the synthesis process, so that the surface acidity distribution and catalytic activity of the molecular sieve can be greatly improved on the premise of not changing the framework. Silicoaluminophosphate series molecular Sieves (SAPO), i.e. adding silicon atoms on the basis of aluminophosphate series molecular sieves, so that a silicon dioxide tetrahedron exists in a framework, and the silicoaluminophosphate series molecular sieves can be used for subsequent surface acidity adjustment and cation exchange modification and can be widely applied to the fields of hydrocarbon conversion and the like. In the current technical report, the silicoaluminophosphate series molecular sieve generally shows higher catalytic activity, but the selectivity and the yield of 2, 6-dimethylnaphthalene are integrally lower, the service life is shorter, carbonization and inactivation are easy, and the requirements of industrial production cannot be met.
Therefore, in the prior art, how to improve the selectivity and yield of 2, 6-dimethylnaphthalene is always the focus of research, and research on developing a high-efficiency alkylation catalyst for synthesizing 2, 6-dimethylnaphthalene is necessary.
Disclosure of Invention
The invention aims to solve the problems of low selectivity, low yield, complex operation, corrosion of equipment and the like in the existing 2, 6-dimethylnaphthalene preparation process, and provides a method for preparing 2, 6-dimethylnaphthalene by high-selectivity catalytic methylation of naphthalene.
In order to achieve the above object, the present invention provides a method for preparing 2, 6-dimethylnaphthalene with high selectivity by naphthalene catalytic methylation, which comprises:
1) preparing a catalyst:
a. adding a phosphorus source and an aluminum source into deionized water at room temperature, stirring for 30-120 min, then sequentially adding a silicon source, an organic amine template and an active metal salt, and stirring to obtain a mixture; the active metal is one or more of Zr, Co, Zn, Bi, V, Cr, W, Mo and Ce;
b. and (b) putting the mixture prepared in the step a into a crystallization kettle with a polytetrafluoroethylene lining for hydrothermal crystallization to obtain colloidal suspension.
c. B, cooling the colloidal suspension crystallized in the step b at room temperature, washing with water to be neutral, filtering, separating and drying, roasting to remove the template agent, taking out solid powder, and performing pressure forming and sieving to obtain 20-40-mesh particles;
2) putting the 20-40 mesh catalyst obtained in the step 1) into a catalyst bed layer of a fixed bed reactor to participate in reaction, introducing inert gas at the temperature of 400-500 ℃ to activate for 1-2 h, and then reducing the temperature to 350-450 ℃;
3) uniformly mixing naphthalene, methanol and a solvent according to a molar ratio of 1: 2.5-10: 2.5-5 to prepare a raw material solution, injecting the raw material solution into a catalyst bed layer of a fixed bed reactor by using a pressure pump, and keeping the pressure pump at normal pressure and a mass space velocity of 1-6 h-1And carrying out alkylation reaction for 1-6 h under the condition of (1) to obtain the 2, 6-dimethylnaphthalene.
The molar ratio of the aluminum source to the silicon source to the phosphorus source to the organic amine template to the deionized water is 1-2: 0.3-1.2: 1-2: 0.5-1: 20-80.
The molar ratio of the active metal to the aluminum is 0.01-0.1: 1.
The solvent is one of 1,2, 4-mesitylene or 3, 4-dichlorotrifluorotoluene, and is preferably 3, 4-dichlorotrifluorotoluene.
The aluminum source is pseudo-boehmite or gamma-alumina, preferably pseudo-boehmite.
The phosphorus source is any one of orthophosphoric acid, ammonium hydrogen phosphate and ammonium dihydrogen phosphate, orthophosphoric acid is preferred, and the mass concentration of orthophosphoric acid is more preferably 60-85%.
The organic amine template is one of di-n-propylamine, tetraethylammonium hydroxide and tetraethylammonium bromide, and is preferably di-n-propylamine.
The active metal salt is one of nitrate, acetate and ammonium salt.
The molar ratio of silicon to aluminum in the catalyst molecular sieve prepared by the method is (0.15-1.2): 1.
The invention adopts the above technology, and solves the technical problems of low selectivity, low yield and the like in the existing 2, 6-dimethylnaphthalene preparation process. Compared with the background art, the invention has the following advantages:
the selectivity of the 2, 6-dimethylnaphthalene prepared by the method is up to 90%, the highest yield is up to 46%, the method is far higher than other preparation methods in the prior art, the high-selectivity preparation of the 2, 6-dimethylnaphthalene is fully realized, and a new thought is provided for subsequent industrial production.
The catalysts used in the invention are SAPO-11 molecular sieves doped with different series of different silica-alumina ratios and different active metals, and the molecular sieves have appropriate surface acidity, larger specific surface area and highly shape-selective pore size due to the addition of the active metals and the regulation and control of different silica-alumina ratios, so that the molecular sieves have extremely high selectivity in the process of catalyzing naphthalene methylation, and the yield of target products is obviously improved.
The series SAPO-11 molecular sieve catalyst synthesized by the invention is used for catalyzing naphthalene alkylation reaction to prepare 2, 6-dimethylnaphthalene, the process belongs to heterogeneous gas-solid phase contact catalytic reaction, the problems of equipment corrosion, difficult separation from products, environmental pollution and the like of homogeneous catalysts such as solid acid and the like are solved, and compared with other decalin-based catalysts, the series SAPO-11 molecular sieve catalyst has higher performance, higher selectivity and higher yield.
Detailed Description
The invention provides a method for preparing 2, 6-dimethylnaphthalene with high selectivity by naphthalene catalytic methylation, which comprises the following steps:
firstly, catalyst activation: putting a 20-40 mesh molecular sieve into a catalyst bed layer of a fixed bed reactor to participate in reaction, introducing inert gas at the temperature of 400-500 ℃ to activate for 1-2 h, and then cooling to 350-450 ℃;
secondly, alkylation reaction: uniformly mixing naphthalene, methanol and a solvent according to a molar ratio of 1: 2.5-10: 2.5-5 to prepare a raw material solution, injecting the raw material solution into a catalyst bed layer of a fixed bed reactor by using a pressure pump, and keeping the pressure pump at normal pressure and a mass space velocity of 1-6 h-1And carrying out alkylation reaction for 1-6 h under the condition of (1) to obtain the 2, 6-dimethylnaphthalene.
The invention provides a new preparation method for preparing 2, 6-dimethylnaphthalene with high selectivity by alkylation. According to a preferred embodiment of the invention, the alkylating agent is methanol and the solvent is 3, 4-dichlorotrifluorotoluene. Under the preferred embodiment, the selectivity of 2, 6-dimethylnaphthalene in the prepared product is up to 90 percent, and the highest yield can reach 46 percent.
According to the invention, the molar ratio of silicon to aluminum in the catalyst is selected in a wide range, and the molar ratio of silicon to aluminum to phosphorus is 0.3-1.2: 1-2.
According to the present invention, the preparation method of the catalyst comprises:
a. adding a phosphorus source and an aluminum source into deionized water at room temperature, stirring for 30-120 min, adding a silicon source, an organic amine template agent and a series of active metal salts, and stirring to obtain a mixture; the metal element is one or more of Zr, Co, Zn, Bi, V, Cr, W, Mo and Ce;
b. and (b) putting the mixture prepared in the step a into a crystallization kettle with a polytetrafluoroethylene lining for hydrothermal synthesis to obtain colloidal suspension.
c. C, cooling the colloidal suspension crystallized in the step b at room temperature, washing the colloidal suspension with water for multiple times until the colloidal suspension is neutral, filtering and separating the colloidal suspension, drying and baking the colloidal suspension to remove the template agent, taking out solid powder, and then carrying out pressure forming and sieving to obtain catalyst particles with the size of 20-40 meshes;
the aluminum source is pseudo-boehmite or gamma-alumina, preferably pseudo-boehmite.
The phosphorus source is any one of orthophosphoric acid, ammonium hydrogen phosphate and ammonium dihydrogen phosphate, and orthophosphoric acid is preferred.
The organic amine template is one of di-n-propylamine, tetraethylammonium hydroxide and tetraethylammonium bromide, and is preferably di-n-propylamine.
The active metal salt is one of nitrate, acetate or chloride.
In the catalyst, the molar ratio of the active metal element to the aluminum is 0.01-0.1: 1. The doping of the active metal can effectively change the surface acidity of the molecular sieve, thereby integrally changing the alkylation reaction process and improving the selectivity and the yield of the 2, 6-dimethylnaphthalene in the final result.
The aluminum source, the silicon source, the phosphorus source and the organic amine template agent are as follows: the molar ratio of the deionized water is 1-2: 0.3-1.2: 1-2: 0.5-1: 20-80. The adjustment of the silicon-aluminum ratio of the catalyst effectively adjusts the framework structure and the surface center distribution of the molecular sieve, so that the strength of strong acid, medium strong acid and weak acid is improved, the alkylation reaction of methanol and naphthalene is finally suitable, and the target product has high selectivity.
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-dimethylnaphthalene by high selectivity of naphthalene catalytic methylation provided by the invention has the advantages that the reaction process is simple, the product composition is simple, the selectivity of the product 2, 6-dimethylnaphthalene is up to 90% under the self-made SAPO-11 molecular sieve catalyst and modification conditions, the target yield is up to 46%, the yield is obviously higher than that reported by professional literatures in the current field, and the method has obvious industrial application value.
The present invention will be described in detail below by way of examples.
Unless otherwise specified, room temperature means 20 to 30 ℃ and% means mass concentration.
Example 1
First step catalyst preparation: 0.654g of 85 percent orthophosphoric acid and 4g of pseudo-boehmite are added into 12.96ml of deionized water in sequence, stirred for 30min, then 1.08g of 40 percent silica sol is slowly dropped into the solution, the stirring is continued for 30min, 0.1984g of ammonium tungstate hydrate is added into the solution, the stirring is continued for 30min, finally 3.64g of di-n-propylamine is dropped into the solution, the stirring is continued for 2.5h until the liquid is gelatinized, and the solution is transferred into a crystallization kettle for hydrothermal reaction for 24h at 180 ℃. And after crystallization, cooling at room temperature, washing for three times, centrifuging, filtering, drying in an oven at 80 ℃ for 6 hours, calcining in a muffle furnace at 500 ℃ for 4 hours, taking out, and sieving to obtain 20-40-mesh particles to obtain the catalyst S1.
Second step catalyst activation: the method comprises the steps of loading a 20-40-mesh catalyst S1 into a constant temperature area of a stainless steel reaction tube of a fixed bed reactor, filling equal amounts of quartz sand into the upper end and the lower end of the catalyst respectively, activating for 1 hour under the conditions that the temperature is 500 ℃ and the nitrogen flow rate is 16ml/min, and then cooling to 400 ℃ to prepare for reaction.
The third step is catalytic alkylation reaction: weighing raw material naphthalene (3.2g), adding 16ml of 3, 4-dichlorobenzotrifluoride as a solvent, adding methanol (4g) as an alkylating reagent, stirring at room temperature for 5min, fully and uniformly mixing, continuously injecting the raw material liquid into a fixed bed reactor by using a metering pump to carry out alkylation reaction with an activated catalyst S1, wherein the reaction temperature is 400 ℃, the flow rate of the metering pump is 0.5ml/min and the space velocity is 4h under the normal pressure condition-1The reaction time is 2 h. The gas phase analysis showed that the conversion of naphthalene was 51.16%, the selectivity for disubstituted 2, 6-dimethylnaphthalene was 90.71% and the yield was 46.4%.
Example 2
First step catalyst preparation: 0.654g of 85 percent orthophosphoric acid and 4g of pseudo-boehmite are added into 12.96ml of deionized water in sequence and stirred for 30min, then 1.08g of 40 percent silica sol is slowly dripped into the solution, the stirring is continued for 30min, finally 3.64g of di-n-propylamine is dripped into the solution, the stirring is continued for 2.5h until the liquid is gelatinized, and the solution is transferred into a crystallization kettle to be hydrothermal for 24h at 180 ℃. And after crystallization, cooling at room temperature, washing for three times, centrifuging, filtering, drying in an oven at 80 ℃ for 6 hours, calcining in a muffle furnace at 500 ℃ for 4 hours, taking out, and sieving to obtain 20-40-mesh particles to obtain the catalyst S2.
Second step catalyst activation: the method comprises the steps of loading a 20-40-mesh catalyst S2 into a constant temperature area of a stainless steel reaction tube of a fixed bed reactor, filling equal amounts of quartz sand into the upper end and the lower end of the catalyst respectively, activating for 1 hour under the conditions that the temperature is 500 ℃ and the nitrogen flow rate is 16ml/min, and then cooling to 400 ℃ to prepare for reaction.
The third step is catalytic alkylation reaction: weighing naphthalene (3.2g), adding 16ml 3, 4-dichlorobenzotrifluoride as solvent, adding methanol (4g) as alkylating agent, and standing at room temperatureStirring for 5min, mixing, continuously injecting the raw material liquid into the fixed bed reactor with a metering pump, and performing alkylation reaction with the activated catalyst S2 at 400 deg.C and normal pressure with a flow rate of 0.5ml/min and a space velocity of 4h-1The reaction time is 2 h. The gas phase analysis showed that the conversion of naphthalene was 28.06%, the selectivity of disubstituted 2, 6-dimethylnaphthalene was 98.02% and the yield was 27.5%.
Comparative example 2
First step catalyst preparation: following a similar procedure to example 2, except that the quantities of pseudoboehmite, orthophosphoric acid, silica sol and di-n-propylamine were reduced by half, catalyst D2 was obtained.
Second step catalyst activation: catalyst warm-up activation was carried out in the same manner as in example 2.
The third step is catalytic alkylation reaction: the reaction solution is obtained according to the same solution ratio of the example 2, the raw material solution is continuously injected into the fixed bed reactor by a metering pump to carry out alkylation reaction with the activated catalyst D2, the reaction temperature is 400 ℃, the flow rate of the metering pump is 0.5ml/min under the normal pressure condition, and the space velocity is 4h-1The reaction time is 2 h. The gas phase analysis showed that the naphthalene conversion was 22.03%, the selectivity for the disubstituted 2, 6-dimethylnaphthalene was 89.35%, and the yield was 19.68%.
Example 3
First step catalyst preparation: 0.654g of 85 percent orthophosphoric acid and 4g of pseudo-boehmite are added into 12.96ml of deionized water in sequence, stirred for 30min, then 1.08g of 40 percent silica sol is slowly dropped into the solution, the stirring is continued for 30min, then 0.308g of chromium nitrate nonahydrate is added into the solution, the stirring is continued for 30min, finally 3.64g of di-n-propylamine is dropped into the solution, the stirring is continued for 2.5h until the liquid becomes colloid, and the solution is transferred into a crystallization kettle to be hydrothermal for 24h at 180 ℃. And after crystallization, cooling at room temperature, washing for three times, centrifuging, filtering, drying in an oven at 80 ℃ for 6 hours, calcining in a muffle furnace at 500 ℃ for 4 hours, taking out, and sieving to obtain 20-40-mesh particles to obtain the catalyst S3.
Second step catalyst activation: the method comprises the steps of loading a 20-40-mesh catalyst S3 into a constant temperature area of a stainless steel reaction tube of a fixed bed reactor, filling equal amounts of quartz sand into the upper end and the lower end of the catalyst respectively, activating for 1 hour under the conditions that the temperature is 500 ℃ and the nitrogen flow rate is 16ml/min, and then cooling to 400 ℃ to prepare for reaction.
The third step is catalytic alkylation reaction: weighing raw material naphthalene (3.2g), adding 16ml of 3, 4-dichlorobenzotrifluoride as a solvent, adding methanol (4g) as an alkylating reagent, stirring at room temperature for 5min, fully and uniformly mixing, continuously injecting the raw material liquid into a fixed bed reactor by using a metering pump to carry out alkylation reaction with an activated catalyst S2, wherein the reaction temperature is 400 ℃, the flow rate of the metering pump is 0.5ml/min and the space velocity is 4h under the normal pressure condition-1The reaction time is 2 h. The gas phase analysis showed that the conversion of naphthalene was 42.43%, the selectivity for disubstituted 2, 6-dimethylnaphthalene was 92.07% and the yield was 37.14%.
Comparative example 3
First step catalyst preparation: in the same manner as in example 3, catalyst S3 was obtained.
Second step catalyst activation: catalyst warm-up activation was carried out in the same manner as in example 3.
The third step is catalytic alkylation reaction: the same solution ratio as in example 3 was used to obtain a reaction solution, and the raw material solution was continuously injected into the fixed bed reactor by a metering pump at a reaction temperature of 350 ℃ and a flow rate of 0.5ml/min under normal pressure at a space velocity of 4h under an alkylation reaction with the activated catalyst S3-1The reaction time is 2 h. The gas phase analysis showed that the naphthalene conversion was 36.72%, the selectivity for the disubstituted 2, 6-dimethylnaphthalene was 91.68%, and the yield was 33.67%.
Example 4
First step catalyst preparation: 0.654g of 85 percent orthophosphoric acid and 4g of pseudo-boehmite are added into 12.96ml of deionized water in sequence, stirred for 30min, then 1.08g of 40 percent silica sol is slowly dropped into the solution, the stirring is continued for 30min, then 0.092g of ammonium metavanadate is added into the solution, the stirring is continued for 30min, finally 3.64g of di-n-propylamine is dropped into the solution, the stirring is continued for 2.5h until the liquid becomes colloid, and the solution is transferred into a crystallization kettle to be hydrothermal for 24h at 180 ℃. And after crystallization, cooling at room temperature, washing for three times, centrifuging, filtering, drying in an oven at 80 ℃ for 6 hours, calcining in a muffle furnace at 500 ℃ for 4 hours, taking out, and sieving to obtain 20-40-mesh particles to obtain the catalyst S4.
Second step catalyst activation: the method comprises the steps of loading a 20-40-mesh catalyst S4 into a constant temperature area of a stainless steel reaction tube of a fixed bed reactor, filling equal amounts of quartz sand into the upper end and the lower end of the catalyst respectively, activating for 1 hour under the conditions that the temperature is 500 ℃ and the nitrogen flow rate is 16ml/min, and then cooling to 400 ℃ to prepare for reaction.
The third step is catalytic alkylation reaction: weighing raw material naphthalene (3.2g), adding 16ml of 3, 4-dichlorobenzotrifluoride as a solvent, adding methanol (4g) as an alkylating reagent, stirring at room temperature for 5min, fully and uniformly mixing, continuously injecting the raw material liquid into a fixed bed reactor by using a metering pump to carry out alkylation reaction with an activated catalyst S4, wherein the reaction temperature is 400 ℃, the flow rate of the metering pump is 0.5ml/min and the space velocity is 4h under the normal pressure condition-1The reaction time is 2 h. Gas phase analysis shows that the conversion rate of naphthalene is 42.1 percent, the selectivity of the disubstituted 2, 6-dimethylnaphthalene is 88.20 percent, and the yield is 37.14 percent
Example 5
First step catalyst preparation: 0.654g of 85 percent orthophosphoric acid and 4g of pseudo-boehmite are added into 12.96ml of deionized water in sequence and stirred for 30min, then 1.08g of 40 percent silica sol is slowly dropped into the solution and stirred for 30min, then 0.098g of ammonium hexafluorozirconate is added into the solution and stirred for 30min, finally 3.64g of di-n-propylamine is dropped into the solution, the stirring is continued for 2.5h until the liquid becomes colloid, and the liquid is transferred into a crystallization kettle and heated for 24h under 180 ℃. And after crystallization, cooling at room temperature, washing for three times, centrifuging, filtering, drying in an oven at 80 ℃ for 6 hours, calcining in a muffle furnace at 500 ℃ for 4 hours, taking out, and sieving to obtain 20-40-mesh particles to obtain the catalyst S5.
Second step catalyst activation: the method comprises the steps of loading a 20-40-mesh catalyst S5 into a constant temperature area of a stainless steel reaction tube of a fixed bed reactor, filling equal amounts of quartz sand into the upper end and the lower end of the catalyst respectively, activating for 1 hour under the conditions that the temperature is 500 ℃ and the nitrogen flow rate is 16ml/min, and then cooling to 400 ℃ to prepare for reaction.
The third step is catalytic alkylation reaction: weighing the raw material naphthalene (3)2g), adding 16ml of 3, 4-dichlorobenzotrifluoride as a solvent, adding methanol (4g) as an alkylating reagent, stirring for 5min at room temperature, fully and uniformly mixing, and then continuously injecting a raw material solution into a fixed bed reactor by using a metering pump to perform alkylation reaction with the activated catalyst S5, wherein the reaction temperature is 400 ℃, the flow rate of the metering pump is 0.5ml/min under normal pressure, and the space velocity is 4h-1The reaction time is 2 h. The gas phase analysis showed that the conversion of naphthalene was 30.68%, the selectivity of disubstituted 2, 6-dimethylnaphthalene was 87.09%, and the yield was 26.72%.
Example 6
First step catalyst preparation: 0.654g of 85 percent orthophosphoric acid and 4g of pseudo-boehmite are added into 12.96ml of deionized water in sequence, stirred for 30min, then 1.08g of 40 percent silica sol is slowly dropped into the solution, the stirring is continued for 30min, then 0.198g of cobalt nitrate hexahydrate is added into the solution, the stirring is continued for 30min, finally 3.64g of di-n-propylamine is dropped into the solution, the stirring is continued for 2.5h until the liquid becomes colloid, and the liquid is transferred into a crystallization kettle and is heated for 24h under 180 ℃. And after crystallization is finished, cooling at room temperature, washing for three times, centrifuging, filtering, drying in an oven at 80 ℃ for 6 hours, calcining in a muffle furnace at 500 ℃ for 4 hours, taking out, and sieving to obtain 20-40-mesh particles, thereby obtaining the catalyst S6.
Second step catalyst activation: the method comprises the steps of loading a 20-40-mesh catalyst S6 into a constant temperature area of a stainless steel reaction tube of a fixed bed reactor, filling equal amounts of quartz sand into the upper end and the lower end of the catalyst respectively, activating for 1 hour under the conditions that the temperature is 500 ℃ and the nitrogen flow rate is 16ml/min, and then cooling to 400 ℃ to prepare for reaction.
The third step is catalytic alkylation reaction: weighing raw material naphthalene (3.2g), adding 16ml of 3, 4-dichlorobenzotrifluoride as a solvent, adding methanol (4g) as an alkylating reagent, stirring at room temperature for 5min, fully and uniformly mixing, continuously injecting the raw material liquid into a fixed bed reactor by using a metering pump to carry out alkylation reaction with an activated catalyst S6, wherein the reaction temperature is 400 ℃, the flow rate of the metering pump is 0.5ml/min and the space velocity is 4h under the normal pressure condition-1The reaction time is 2 h. The gas phase analysis showed that the conversion of naphthalene was 32.85%, the selectivity of disubstituted 2, 6-dimethylnaphthalene was 89.13%, and the yield was 29.28%.
Example 7
First step catalyst preparation: 0.654g of 85 percent orthophosphoric acid and 4g of pseudo-boehmite are added into 12.96ml of deionized water in sequence, stirred for 30min, then 1.08g of 40 percent silica sol is slowly dropped into the solution, the stirring is continued for 30min, then 0.1g of zinc acetate is added into the solution, the stirring is continued for 30min, finally 3.64g of di-n-propylamine is dropped into the solution, the stirring is continued for 2.5h until the liquid is gelatinized, and the solution is transferred into a crystallization kettle to be hydrothermal for 24h at 180 ℃. And after crystallization, cooling at room temperature, washing for three times, centrifuging, filtering, drying in an oven at 80 ℃ for 6 hours, calcining in a muffle furnace at 500 ℃ for 4 hours, taking out, and sieving to obtain 20-40-mesh particles to obtain the catalyst S7.
The second step of catalyst activation: the method comprises the steps of loading a 20-40-mesh catalyst S7 into a constant-temperature area of a stainless steel reaction tube of a fixed bed reactor, filling equal amounts of quartz sand into the upper end and the lower end of the catalyst respectively, activating for 1 hour under the conditions that the temperature is 500 ℃ and the nitrogen flow rate is 16ml/min, and then cooling to 400 ℃ to prepare for reaction.
The third step is catalytic alkylation reaction: weighing raw material naphthalene (3.2g), adding 16ml of 3, 4-dichlorobenzotrifluoride as a solvent, adding methanol (4g) as an alkylating reagent, stirring at room temperature for 5min, fully and uniformly mixing, continuously injecting the raw material liquid into a fixed bed reactor by using a metering pump, carrying out alkylation reaction with the activated catalyst S7, wherein the reaction temperature is 400 ℃, the flow rate of the metering pump is 0.5ml/min and the space velocity is 4h under the normal pressure condition-1The reaction time is 2 h. The gas phase analysis showed that the conversion of naphthalene was 28.16%, the selectivity of disubstituted 2, 6-dimethylnaphthalene was 88.08%, and the yield was 24.8%.
Example 8
First step catalyst preparation: 0.654g of 85 percent orthophosphoric acid and 4g of pseudo-boehmite are added into 12.96ml of deionized water in sequence, stirred for 30min, then 1.08g of 40 percent silica sol is slowly dropped into the solution, the stirring is continued for 30min, then 0.0736g of ammonium molybdate tetrahydrate is added into the solution, the stirring is continued for 30min, finally 3.64g of di-n-propylamine is dropped into the solution, the stirring is continued for 2.5h until the liquid becomes colloid, and the liquid is transferred into a crystallization kettle and is heated for 24h under water at 180 ℃. And after crystallization, cooling at room temperature, washing for three times, centrifuging, filtering, drying in an oven at 80 ℃ for 6 hours, calcining in a muffle furnace at 500 ℃ for 4 hours, taking out, and sieving to obtain 20-40-mesh particles to obtain the catalyst S9.
Second step catalyst activation: the method comprises the steps of loading a 20-40-mesh catalyst S9 into a constant temperature area of a stainless steel reaction tube of a fixed bed reactor, filling equal amounts of quartz sand into the upper end and the lower end of the catalyst respectively, activating for 1 hour under the conditions that the temperature is 500 ℃ and the nitrogen flow rate is 16ml/min, and then cooling to 400 ℃ to prepare for reaction.
The third step is catalytic alkylation reaction: weighing raw material naphthalene (3.2g), adding 16ml of 3, 4-dichlorobenzotrifluoride as a solvent, adding methanol (4g) as an alkylating reagent, stirring at room temperature for 5min, fully and uniformly mixing, continuously injecting the raw material liquid into a fixed bed reactor by using a metering pump to carry out alkylation reaction with an activated catalyst S9, wherein the reaction temperature is 400 ℃, the flow rate of the metering pump is 0.5ml/min and the space velocity is 4h under the normal pressure condition-1The reaction time is 2 h. The gas phase analysis showed that the conversion of naphthalene was 35.31%, the selectivity of disubstituted 2, 6-dimethylnaphthalene was 87.42% and the yield was 30.87%.
Example 9
First step catalyst preparation: 0.654g of 85 percent orthophosphoric acid and 4g of pseudo-boehmite are added into 12.96ml of deionized water in sequence, stirred for 30min, then 1.08g of 40 percent silica sol is slowly dropped into the solution, the stirring is continued for 30min, then 0.056g of cerium trifluoride is added into the solution, the stirring is continued for 30min, finally 3.64g of di-n-propylamine is dropped into the solution, the stirring is continued for 2.5h until the liquid becomes gelatinous, and the solution is transferred into a crystallization kettle for hydrothermal reaction for 24h at 180 ℃. And after crystallization, cooling at room temperature, washing for three times, centrifuging, filtering, drying in an oven at 80 ℃ for 6 hours, calcining in a muffle furnace at 500 ℃ for 4 hours, taking out, and sieving to obtain 20-40-mesh particles to obtain the catalyst S10.
The second step of catalyst activation: the method comprises the steps of loading a 20-40-mesh catalyst S10 into a constant temperature area of a stainless steel reaction tube of a fixed bed reactor, filling equal amounts of quartz sand into the upper end and the lower end of the catalyst respectively, activating for 1 hour under the conditions that the temperature is 500 ℃ and the nitrogen flow rate is 16ml/min, and then cooling to 400 ℃ to prepare for reaction.
The third step is catalytic alkylation reaction: weighing raw material naphthalene (3.2g), adding 16ml of 3, 4-dichlorobenzotrifluoride as a solvent, adding methanol (4g) as an alkylating reagent, stirring at room temperature for 5min, fully and uniformly mixing, continuously injecting the raw material liquid into a fixed bed reactor by using a metering pump to carry out alkylation reaction with an activated catalyst S10, wherein the reaction temperature is 400 ℃, the flow rate of the metering pump is 0.5ml/min and the space velocity is 4h under the normal pressure condition-1The reaction time is 2 h. The gas phase analysis showed that the conversion of naphthalene was 41.76%, the selectivity of disubstituted 2, 6-dimethylnaphthalene was 91.8% and the yield was 38.34%.
Example 10
First step catalyst preparation: 0.654g of 85 percent orthophosphoric acid and 4g of pseudo-boehmite are added into 12.96ml of deionized water in sequence and stirred for 30min, then 0.54g of 40 percent silica sol is slowly dripped into the solution, the stirring is continued for 30min, finally 3.64g of di-n-propylamine is dripped into the solution, the stirring is continued for 2.5h until the liquid is gelatinized, and the solution is transferred into a crystallization kettle to be hydrothermal for 24h at 180 ℃. And after crystallization, cooling at room temperature, washing for three times, centrifuging, filtering, drying in an oven at 80 ℃ for 6 hours, calcining in a muffle furnace at 500 ℃ for 4 hours, taking out, and sieving to obtain 20-40-mesh particles to obtain the catalyst S11.
Second step catalyst activation: the method comprises the steps of loading a 20-40-mesh catalyst S11 into a constant temperature area of a stainless steel reaction tube of a fixed bed reactor, filling equal amounts of quartz sand into the upper end and the lower end of the catalyst respectively, activating for 1 hour under the conditions that the temperature is 500 ℃ and the nitrogen flow rate is 16ml/min, and then cooling to 400 ℃ to prepare for reaction.
The third step is catalytic alkylation reaction: weighing raw material naphthalene (3.2g), adding 16ml of 3, 4-dichlorobenzotrifluoride as a solvent, adding methanol (4g) as an alkylating reagent, stirring at room temperature for 5min, fully and uniformly mixing, continuously injecting the raw material liquid into a fixed bed reactor by using a metering pump to carry out alkylation reaction with an activated catalyst S11, wherein the reaction temperature is 400 ℃, the flow rate of the metering pump is 0.5ml/min and the space velocity is 4h under the normal pressure condition-1The reaction time is 2 h. The gas phase analysis showed that the conversion of naphthalene was 23.16%, the selectivity of disubstituted 2, 6-dimethylnaphthalene was 89.83% and the yield was 20.81％。
Example 11
First step catalyst preparation: 0.654g of 85 percent orthophosphoric acid and 4g of pseudo-boehmite are added into 12.96ml of deionized water in sequence and stirred for 30min, then 2.16g of 40 percent silica sol is slowly dripped into the solution, the stirring is continued for 30min, finally 3.64g of di-n-propylamine is dripped into the solution, the stirring is continued for 2.5h until the liquid is gelatinized, and the solution is transferred into a crystallization kettle to be hydrothermal for 24h at 180 ℃. And after crystallization, cooling at room temperature, washing for three times, centrifuging, filtering, drying in an oven at 80 ℃ for 6 hours, calcining in a muffle furnace at 500 ℃ for 4 hours, taking out, and sieving to obtain 20-40-mesh particles to obtain the catalyst S12.
Second step catalyst activation: the method comprises the steps of loading a 20-40-mesh catalyst S12 into a constant temperature area of a stainless steel reaction tube of a fixed bed reactor, filling equal amounts of quartz sand into the upper end and the lower end of the catalyst respectively, activating for 1 hour under the conditions that the temperature is 500 ℃ and the nitrogen flow rate is 16ml/min, and then cooling to 400 ℃ to prepare for reaction.
The third step is catalytic alkylation reaction: weighing raw material naphthalene (3.2g), adding 16ml of 3, 4-dichlorobenzotrifluoride as a solvent, adding methanol (4g) as an alkylating reagent, stirring at room temperature for 5min, fully and uniformly mixing, continuously injecting the raw material liquid into a fixed bed reactor by using a metering pump to carry out alkylation reaction with an activated catalyst S12, wherein the reaction temperature is 400 ℃, the flow rate of the metering pump is 0.5ml/min and the space velocity is 4h under the normal pressure condition-1The reaction time is 2 h. The gas phase analysis showed that the conversion of naphthalene was 22.04%, the selectivity of disubstituted 2, 6-dimethylnaphthalene was 91.66% and the yield was 20.20%.
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, numerous simple variations can be made to the technical solution of the invention, including combinations of the technical features in any other suitable way, and these simple variations and combinations should also be considered as the disclosure of the invention, all falling within the scope of the invention.

Claims (9)

1. A method for preparing 2, 6-dimethylnaphthalene with high selectivity by naphthalene catalytic methylation is characterized by comprising the following steps:
1) preparing a catalyst:
a. adding a phosphorus source and an aluminum source into deionized water at room temperature, stirring for 30-120 min, adding a silicon source, an organic amine template and an active metal salt, and stirring to obtain a mixture, wherein the active metal is one or more of Zr, Co, Zn, Bi, V, Cr, W, Mo and Ce;
b. b, putting the mixture prepared in the step a into a crystallization kettle with a polytetrafluoroethylene lining for hydrothermal crystallization to obtain colloidal suspension;
c. c, cooling the colloidal suspension crystallized in the step b at room temperature, washing with water to be neutral, filtering, separating, drying, baking and removing the template agent, taking out solid powder, and then carrying out pressure forming and sieving to obtain catalyst particles with the size of 20-40 meshes;
2) putting the catalyst with the size of 20-40 meshes obtained in the step 1) into a catalyst bed layer of a fixed bed reactor to participate in reaction, introducing inert gas at the temperature of 400-500 ℃ to activate for 1-2 h, and then reducing the temperature to 350-450 ℃;
3) uniformly mixing naphthalene, methanol and a solvent according to a molar ratio of 1: 2.5-10: 2.5-5 to prepare a raw material solution, injecting the raw material solution into a catalyst bed layer of a fixed bed reactor by using a pressure pump, and keeping the pressure pump at normal pressure and a mass space velocity of 1-6 h-1And carrying out alkylation reaction for 1-6 h under the condition of (1) to obtain the 2, 6-dimethylnaphthalene.
2. The method of claim 1, wherein the molar ratio of the aluminum source, the silicon source, the phosphorus source, the organic amine template and the deionized water is 1-2: 0.3-1.2: 1-2: 0.5-1: 20 to 80 parts.
3. The method according to claim 1, wherein the molar ratio of the active metal element to the aluminum is 0.01 to 0.1: 1.
4. The process of any one of claims 1 to 3 wherein the aluminum source is pseudoboehmite or gamma-alumina.
5. The method according to any one of claims 1 to 3, wherein the phosphorus source is any one of orthophosphoric acid, ammonium hydrogen phosphate and ammonium dihydrogen phosphate.
6. The method of any one of claims 1-3, wherein the organoamine templating agent is one of di-n-propylamine, tetraethylammonium hydroxide, tetraethylammonium bromide.
7. The process of any one of claims 1 to 3, wherein the solvent is one of 1,2, 4-mesitylene or 3, 4-dichlorotrifluorotoluene.
8. A method according to any one of claims 1 to 3, wherein the active metal salt is one of a nitrate, acetate or chloride.
9. The method according to any one of claims 1 to 3, wherein the stirring in step 1) is performed at a rotation speed of 400 to 800r/s, the stirring time is 0.5 to 4 hours, the crystallization temperature is 150 to 280 ℃, the crystallization time is 12 to 48 hours, the drying temperature is 60 to 80 ℃, the time is 4 to 8 hours, and the calcination temperature is 450 to 550 ℃.
CN202210066483.XA 2022-01-20 2022-01-20 Method for preparing 2, 6-dimethylnaphthalene with high selectivity by naphthalene catalytic methylation Pending CN114539014A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN202210066483.XA CN114539014A (en) 2022-01-20 2022-01-20 Method for preparing 2, 6-dimethylnaphthalene with high selectivity by naphthalene catalytic methylation

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202210066483.XA CN114539014A (en) 2022-01-20 2022-01-20 Method for preparing 2, 6-dimethylnaphthalene with high selectivity by naphthalene catalytic methylation

Publications (1)

Publication Number Publication Date
CN114539014A true CN114539014A (en) 2022-05-27

Family

ID=81672284

Family Applications (1)

Application Number Title Priority Date Filing Date
CN202210066483.XA Pending CN114539014A (en) 2022-01-20 2022-01-20 Method for preparing 2, 6-dimethylnaphthalene with high selectivity by naphthalene catalytic methylation

Country Status (1)

Country Link
CN (1) CN114539014A (en)

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2005255537A (en) * 2004-03-09 2005-09-22 Nippon Steel Chem Co Ltd Method for supercritical methylation of aromatic compound
JP2006257032A (en) * 2005-03-17 2006-09-28 Nippon Steel Chem Co Ltd Method for methylating aromatic compound
CN102746101A (en) * 2012-07-26 2012-10-24 黑龙江大学 Method for preparing 2,6-dimethylnaphthalene by catalyzing naphthalene alkylation reaction with CoAPO-11 molecular sieve
CN105566052A (en) * 2015-12-24 2016-05-11 太原科技大学 Method for using CuSAPO-11 molecular sieve for preparation of 2,6-dimethylnaphthalene

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2005255537A (en) * 2004-03-09 2005-09-22 Nippon Steel Chem Co Ltd Method for supercritical methylation of aromatic compound
JP2006257032A (en) * 2005-03-17 2006-09-28 Nippon Steel Chem Co Ltd Method for methylating aromatic compound
CN102746101A (en) * 2012-07-26 2012-10-24 黑龙江大学 Method for preparing 2,6-dimethylnaphthalene by catalyzing naphthalene alkylation reaction with CoAPO-11 molecular sieve
CN105566052A (en) * 2015-12-24 2016-05-11 太原科技大学 Method for using CuSAPO-11 molecular sieve for preparation of 2,6-dimethylnaphthalene

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
王潇潇等: "SAPO-11分子筛催化合成2,6-二甲基萘", 《石油化工》 *

Similar Documents

Publication Publication Date Title
WO1993000166A1 (en) Process for the transformation of vanadium/phosphorus mixed oxide catalyst precursors into active catalysts for the production of maleic anhydride
CN107185594B (en) Preparation method of Ni-Zn-K-Ru/MOF catalyst
CN112645349B (en) Preparation method and application of mordenite molecular sieve
CN107866215B (en) Catalyst for synthesizing pyromellitic anhydride from durene
CN110152650A (en) A kind of preparing propylene by dehydrogenating propane supported catalyst and preparation method thereof
CN108821306B (en) Preparation method of metal modified hierarchical pore HZSM-5 molecular sieve
CN109574839B (en) Method for directly producing methyl acetate and/or acetic acid by using synthesis gas
JP6229201B2 (en) Composite metal oxide catalyst and method for producing conjugated diene
CN113318774B (en) Modified Co-based catalyst, preparation method and application thereof, and method for preparing propylene by propane anaerobic dehydrogenation
JP3849077B2 (en) Hydrogenation catalyst and method for hydrogenating benzene using said catalyst
CN112409316B (en) Method for catalytic synthesis of benzaldehyde 1, 2-propylene glycol ketal by using hierarchical pore silicoaluminophosphate molecular sieve
CN107262140B (en) 2, 6-dimethylnaphthalene catalyst prepared from 2-methylnaphthalene, preparation and application thereof
CN114539014A (en) Method for preparing 2, 6-dimethylnaphthalene with high selectivity by naphthalene catalytic methylation
CN110801828A (en) Catalyst for preparing olefin by oxidative dehydrogenation of ethane chemical chain and application of catalyst in oxidative dehydrogenation reaction of ethane
CN116726932A (en) Supported nickel-copper catalyst for sterically hindered amine tert-butylaminoethoxy ethanol and preparation method thereof
CN112742464B (en) Preparation method and application method of composite molecular sieve catalyst for synthesizing alkylphenol
CN112619686B (en) Supported non-noble metal dehydrogenation catalyst and preparation method and application thereof
CN112619692A (en) Supported catalyst, preparation method thereof and application thereof in citral preparation
CN111013563A (en) Spinel catalyst for preparing ethylene by ethane dehydrogenation under carbon dioxide atmosphere and preparation method thereof
CN115181018B (en) Method for directionally synthesizing valeric acid by utilizing gamma-valerolactone
CN113117741B (en) Preparation method and application of aluminum-zinc phosphate molecular sieve catalyst
CN114713278B (en) Preparation method of full-crystallization ZSM-35 molecular sieve and application of full-crystallization ZSM-35 molecular sieve in olefin isomerization reaction
CN115160182B (en) Method for producing salicylonitrile by methyl salicylate continuous method
CN111410602B (en) Preparation method of anthraquinone
CN114160120B (en) Preparation method of catalyst for producing adiponitrile from adipate

Legal Events

Date Code Title Description
PB01 Publication
PB01 Publication
SE01 Entry into force of request for substantive examination
SE01 Entry into force of request for substantive examination
AD01 Patent right deemed abandoned

Effective date of abandoning: 20240126

AD01 Patent right deemed abandoned