Method for producing 2, 6-xylenol by phenol alkylation
阅读说明：本技术 一种苯酚烷基化生产2,6-二甲酚的方法 (Method for producing 2, 6-xylenol by phenol alkylation ) 是由 王坤院 刘中民 于 2018-08-01 设计创作，主要内容包括：本申请公开了一种苯酚烷基化生产2,6-二甲酚的方法,其特征在于,包括：将含有苯酚和甲醇的原料气依次连续通过包含烷基化催化剂的反应器,烷基化反应,获得2,6-二甲酚；其中,所述反应器包括第一反应器和第二反应器,所述原料气依次连续通过第一反应器和第二反应器；所述烷基化催化剂中包含分子筛。所述方法获得的反应产物中2,6-二甲酚选择性可达99％,催化剂稳定性好。该生产过程中无设备腐蚀,是一种环境友好的2,6-二甲酚生产工艺,具有良好的工业应用前景。(The application discloses a method for producing 2, 6-xylenol by phenol alkylation, which is characterized by comprising the following steps: continuously passing raw material gas containing phenol and methanol through a reactor containing an alkylation catalyst in sequence for alkylation reaction to obtain 2, 6-xylenol; wherein the reactor comprises a first reactor and a second reactor, and the feed gas sequentially and continuously passes through the first reactor and the second reactor; the alkylation catalyst comprises a molecular sieve. The selectivity of 2, 6-xylenol in the reaction product obtained by the method can reach 99%, and the catalyst has good stability. The production process has no equipment corrosion, is an environment-friendly 2, 6-xylenol production process, and has good industrial application prospect.)
1. A process for the alkylation of phenol to produce 2, 6-xylenol comprising:
continuously passing raw material gas containing phenol and methanol through a reactor containing an alkylation catalyst in sequence for alkylation reaction to obtain 2, 6-xylenol;
wherein the reactor comprises a first reactor and a second reactor, and the feed gas sequentially and continuously passes through the first reactor and the second reactor;
the alkylation catalyst comprises a molecular sieve.
2. The process of claim 1, wherein the alkylation catalyst comprises a molecular sieve and a binder;
the molar silica-alumina ratio of the molecular sieve is 20-200;
the content of the molecular sieve in the alkylation catalyst is 30-85 wt%;
preferably, the molecular sieve is selected from one of a hydrogen type molecular sieve and an ammonium type molecular sieve;
preferably, the molecular sieve is at least one selected from ZSM-5, MCM-22 and BETA molecular sieve;
preferably, the binder is selected from at least one of silica sol, diatomaceous earth, silica, boehmite, alumina sol, alumina, kaolin.
3. The method of claim 2, wherein the alkylation catalyst is prepared by a method comprising: mixing and molding a molecular sieve and a binder, drying, roasting I, then carrying out modification treatment, and roasting II to obtain the alkylation catalyst;
the modification treatment includes at least one of oxide modification and water vapor treatment.
4. The method of claim 3, wherein the firing I conditions are: roasting for 4-10 hours at 500-700 ℃;
preferably, the roasting II is carried out for 2-10 hours at the temperature of 500-800 ℃.
5. The method of claim 3, wherein the oxide modification is at least one of a metal oxide modification;
preferably, the oxide is selected from at least one of calcium oxide, strontium oxide and barium oxide; the weight content of the oxide in the product obtained after the oxide modification is 1-15%; and/or the oxide is selected from at least one of bismuth trioxide, lanthanum trioxide and cerium oxide; the weight content of the oxide in the product obtained after the oxide modification is 1-10%.
6. The method of claim 3, wherein the oxide modification comprises: soaking a substance to be treated in a solution containing an oxide source, drying and roasting III;
preferably, the dipping time is 10-36 hours;
the roasting condition of III is as follows: roasting at 550-700 ℃ for 3-10 hours;
the water vapor treatment comprises: treating with steam at 350-800 deg.C for 0.5-10 hr;
preferably, the water vapor is 100% water vapor; the pressure of the water vapor treatment is 1.0-3.0 MPa.
7. The process of claim 3, wherein the alkylation catalyst is prepared by a process comprising:
(1) firstly, mixing a molecular sieve and a binder, molding, drying, and roasting at 550-700 ℃ for 4-10 hours;
(2) modifying the catalyst formed in the step (1) by using an oxide, drying, and roasting at 550-700 ℃ for 3-10 hours;
(3) treating the catalyst prepared in the step (2) by using water vapor at 300-800 ℃ for 0.5-10 hours, drying, and roasting at 500-800 ℃ for 2-10 hours.
8. The method according to claim 1, wherein the reaction temperature of the first reactor is 240-380 ℃;
the reaction temperature of the second reactor is 320-450 ℃;
the feeding weight space velocity is 0.5-20 h-1；
The reaction pressure is normal pressure;
preferably, the reaction temperature of the first reactor is 280-320 ℃;
preferably, the reaction temperature of the second reactor is 320-380 ℃;
preferably, the feeding weight space velocity is 1-10 h-1。
9. The method according to claim 1, wherein the molar ratio of methanol to phenol is 6:1 to 1: 1;
the feed gas also comprises a diluent gas;
preferably, the mol ratio of the dilution gas to the phenol is 0.5-20;
preferably, the diluent gas is selected from nitrogen or water vapor.
10. The process of claim 1, wherein the phenol alkylation process for producing 2, 6-xylenol comprises: taking phenol and methanol as raw materials, and adopting a two-stage method;
preheating raw material gas, mixing the preheated raw material gas with diluent gas in proportion, and continuously and sequentially passing through a reactor provided with an alkylation catalyst bed layer to carry out alkylation reaction to generate 2, 6-xylenol; the reaction temperature of the first reactor is 240-350 ℃, the reaction temperature of the second reactor is 340-450 ℃, and the feeding weight space velocity is 0.5-20 h-1The reaction pressure is normal pressure; the alkylation catalyst consists of a molecular sieve and a binder and is prepared by modification treatment;
the modification treatment includes at least one of oxide modification and water vapor treatment.
Technical Field
The application relates to a method for producing 2, 6-xylenol by phenol alkylation, belonging to the field of chemical engineering.
Background
2, 6-xylenol is a monomer for the synthesis of polyphenylene ethers. Polyphenylene oxide is an excellent thermoplastic, one of five major engineering plastics. The polyphenyl ether has certain mechanical properties superior to polycarbonate, wide applicable temperature range, high hydrolysis resistance, acid, alkali and salt resistance, outstanding creep resistance, good dimensional stability and excellent electrical insulation. It can be used as a mechanical substitute for nonferrous metals, particularly bronze, as silent gears, cam bearings, conveyor parts, screws, etc.; electrically used as a bobbin, an insulating support, a housing of a television set, or the like; can be used as corrosion-resistant pump blades, pipelines, valves and the like in the chemical industry; in the medical industry as a component of surgery; the product is used as automobile outer shell and parts in automobiles.
The traditional 2, 6-xylenol process catalyst can be summarized into two systems, one is an iron-based composite catalyst of iron oxide modified by vanadium, titanium, germanium, zirconium and the like. One is magnesium-series composite catalyst with magnesium oxide modified with Si, V, Zr, etc. The magnesium catalyst has high reaction temperature (400 ℃), more methanol decomposition byproducts, high energy consumption and poor economical efficiency. The iron-based catalyst comprises Fe-Zr, Fe-V2O5The composite catalyst has the defects of volatility, frequent regeneration of the catalyst and the like in the reaction process.
Disclosure of Invention
According to one aspect of the application, the method for producing the 2, 6-xylenol by phenol alkylation is provided, the method takes phenol and methanol as raw materials, takes a molecular sieve as a catalyst, adopts a two-stage method to produce the 2, 6-xylenol, and has good catalyst stability, and the device is easy to realize large-scale production. No equipment corrosion in the production process, and is an environment-friendly process with good industrial application prospect.
The technical problems solved are the defects of short service life of the catalyst, frequent regeneration of the catalyst and the like in the traditional 2, 6-xylenol production technology. The invention provides a method for producing 2, 6-xylenol, which takes phenol and methanol as raw materials, produces the 2, 6-xylenol on a molecular sieve catalyst in a high selectivity way, does not corrode equipment in the production process, does not generate a large amount of industrial wastewater, and is an environment-friendly green process.
In order to solve the problems, the technical scheme adopted by the invention is as follows: a method for producing 2, 6-xylenol is a method for producing 2, 6-xylenol by using phenol and methanol as raw materials and adopting a two-stage method. The raw material gas is preheated and then mixed with the diluent gas continuouslyThe mixture passes through a reactor filled with an alkylation catalyst bed layer for the second time, the reaction temperature of the first reactor is 240-350 ℃, the reaction temperature of the second reactor is 340-450 ℃, and the feeding weight space velocity is 0.5-20 h-1And carrying out alkylation reaction under normal pressure to generate 2, 6-xylenol. The alkylation catalyst consists of a molecular sieve and a binder and is prepared by oxide modification and water vapor treatment.
The selectivity of the 2, 6-xylenol in the product obtained by the method for producing the 2, 6-xylenol by phenol alkylation is more than 98 percent.
The selectivity of the 2, 6-xylenol in the product obtained by the method for producing the 2, 6-xylenol by alkylating phenol reaches 99 percent.
The conversion rate of the phenol in the method for producing the 2, 6-xylenol by alkylating the phenol reaches more than 50 percent.
The conversion rate of the phenol in the method for producing the 2, 6-xylenol by alkylating the phenol reaches more than 80 percent.
The method for producing the 2, 6-xylenol by alkylating the phenol is characterized by comprising the following steps:
continuously passing raw material gas containing phenol and methanol through a reactor containing an alkylation catalyst in sequence for alkylation reaction to obtain 2, 6-xylenol;
wherein the reactor comprises a first reactor and a second reactor, and the feed gas sequentially and continuously passes through the first reactor and the second reactor;
the alkylation catalyst comprises a molecular sieve.
Optionally, the alkylation catalyst is composed of a molecular sieve and a binder, and is prepared by oxide modification and water vapor treatment.
Optionally, the alkylation catalyst comprises a molecular sieve and a binder;
the molar silica-alumina ratio of the molecular sieve is 20-200;
the content of the molecular sieve in the alkylation catalyst is 30-85 wt%.
Alternatively, the molecular sieve has an upper limit on the molar silica to alumina ratio selected from 30, 40, 50, 60, 80, 100, or 200; the lower limit is selected from 20, 30, 40, 50, 60, 80 or 100.
Optionally, the upper limit of the amount of the molecular sieve in the alkylation catalyst is selected from 50 wt%, 60 wt%, 70 wt%, 80 wt%, or 85 wt%; the lower limit is selected from 30 wt%, 50 wt%, 60 wt%, 70 wt% or 80 wt%.
Optionally, the molecular sieve is selected from one of a hydrogen type molecular sieve and an ammonium type molecular sieve.
Optionally, the molecular sieve is at least one selected from ZSM-5, MCM-22 and BETA molecular sieve.
Optionally, the binder is selected from at least one of silica sol, diatomaceous earth, silica, boehmite, alumina sol, alumina, kaolin.
Optionally, the binder is one or more of silica sol, diatomite and silica.
Optionally, the binder is one or more of boehmite, alumina sol, alumina or kaolin.
Alternatively, the method of preparing the alkylation catalyst comprises: mixing and molding a molecular sieve and a binder, drying, roasting I, then carrying out modification treatment, and roasting II to obtain the alkylation catalyst;
the modification treatment includes at least one of oxide modification and water vapor treatment.
Optionally, the shaping means comprises spray drying or extrusion.
Optionally, the hybrid molding comprises: and mixing the molecular sieve and the binder, and extruding into strips. And a proper amount of extrusion aid can be added in the extrusion molding process.
Optionally, an extrusion aid is added in the mixing and forming process.
Optionally, the extrusion aid is selected from 10 wt% dilute nitric acid.
Alternatively, the shaping may be obtained by means known in the art.
Optionally, the conditions of the roasting I are as follows: roasting for 4-10 hours at 500-700 ℃.
Optionally, the roasting II is carried out for 2-10 hours at 500-800 ℃.
Optionally, the conditions of the roasting I are as follows: roasting at 550-700 ℃ for 4-10 hours.
Optionally, the upper temperature limit of the calcination I is selected from 550 ℃, 600 ℃, 650 ℃, or 700 ℃; the lower limit is selected from 500 deg.C, 550 deg.C, 600 deg.C or 650 deg.C.
Optionally, the upper time limit of calcination I is selected from 5 hours, 6 hours, 7 hours, 8 hours, 9 hours, or 10 hours; the lower limit is selected from 4 hours, 5 hours, 6 hours, 7 hours, 8 hours, or 9 hours.
Optionally, the upper temperature limit of roasting II is selected from 550 ℃, 600 ℃, 650 ℃, 700 ℃, 750 ℃ or 800 ℃; the lower limit is selected from 500 deg.C, 550 deg.C, 600 deg.C, 650 deg.C, 700 deg.C or 750 deg.C.
Optionally, the upper time limit for calcination II is selected from 3 hours, 5 hours, 6 hours, 7 hours, 8 hours, or 10 hours; the lower limit is selected from 2 hours, 3 hours, 5 hours, 6 hours, 7 hours, or 8 hours.
Optionally, the weight content of the oxide in the product obtained after the modification of the oxide is 1-15%.
Optionally, the upper limit of the weight content of the oxide in the product obtained after the oxide modification is selected from 5%, 6%, 8%, 9%, 10%, 12% or 15%; the lower limit of the content by weight is selected from 1%, 5%, 6%, 8%, 9%, 10% or 12%.
Optionally, the oxide is one of calcium oxide, strontium oxide and barium oxide, and the weight content is 1-15%.
The oxide is one of bismuth trioxide, lanthanum trioxide or cerium oxide, and the weight content is 1-10%.
Optionally, the oxide modification is at least one of a metal oxide modification.
Optionally, the oxide is selected from at least one of calcium oxide, strontium oxide and barium oxide; the weight content of the oxide in the product obtained after the oxide modification is 1-15%; and/or
The oxide is at least one of bismuth trioxide, lanthanum trioxide and cerium oxide; the weight content of the oxide in the product obtained after the oxide modification is 1-10%.
Optionally, the oxide modification comprises: and (3) soaking a substance to be treated in a solution containing an oxide source, drying and roasting III.
The oxide source is a substance which is obtained by roasting to obtain a corresponding oxide.
Optionally, the oxide source is selected from at least one of the metal salts corresponding to the metals in the oxide.
Optionally, the dipping time is 10-36 hours;
the roasting condition of III is as follows: roasting at 550-700 ℃ for 3-10 hours;
the water vapor treatment comprises: treating with steam at 350-800 deg.C for 0.5-10 hr.
Optionally, the upper time limit for the impregnation is selected from 12 hours, 20 hours, 24 hours, or 36 hours; the lower limit is selected from 10 hours, 12 hours, 20 hours or 24 hours.
Optionally, the concentration of the solution containing the oxide source is 2.1 to 30.7 wt%.
Optionally, the upper temperature limit of the firing III is selected from 600 ℃, 650 ℃, or 700 ℃; the lower limit is selected from 550 ℃, 600 ℃ or 650 ℃.
Optionally, the upper time limit for the calcining III is selected from 4 hours, 5 hours, 6 hours, 7 hours, 8 hours, 9 hours, or 10 hours; the lower limit is selected from 3 hours, 4 hours, 5 hours, 6 hours, 7 hours, 8 hours, or 9 hours.
Optionally, the water vapor is 100% water vapor; the pressure of the water vapor treatment is 1.0-3.0 MPa.
Optionally, the steam treatment is 100% steam, the treatment temperature is 300-800 ℃, the treatment time is 0.5-10 hours, and the pressure is 1.0-3.0 MPa.
Optionally, the upper temperature limit of the water vapor treatment is selected from 400 ℃, 450 ℃, 550 ℃, 600 ℃, 700 ℃ or 800 ℃; the lower limit is selected from 350 deg.C, 400 deg.C, 450 deg.C, 550 deg.C, 600 deg.C or 700 deg.C.
Optionally, the upper limit of time for the water vapor treatment is selected from 2 hours, 4 hours, 5 hours, 6 hours, or 10 hours; the lower limit is selected from 0.5 hour, 2 hours, 4 hours, 5 hours or 6 hours.
Optionally, the upper pressure limit of the water vapor treatment is selected from 2.0MPa, 2.5MPa or 3.0 MPa; the lower limit is selected from 1.0MPa, 2.0MPa or 2.5 MPa.
Alternatively, the method of preparing the alkylation catalyst comprises:
(1) firstly, mixing a molecular sieve and a binder, molding, drying, and roasting at 550-700 ℃ for 4-10 hours;
(2) modifying the catalyst formed in the step (1) by using an oxide, drying, and roasting at 550-700 ℃ for 3-10 hours;
(3) treating the catalyst prepared in the step (2) by using water vapor at 300-800 ℃ for 0.5-10 hours, drying, and roasting at 500-800 ℃ for 2-10 hours.
Alternatively, the method of preparing the alkylation catalyst comprises:
(1') mixing and molding the molecular sieve and the binder, drying, and roasting at 550-700 ℃ for 4-10 hours;
(2') modifying the catalyst formed in the step (1) with an oxide at least once, drying, and roasting at 550-700 ℃ for 3-10 hours.
Optionally, the reaction temperature of the first reactor is 240-380 ℃;
the reaction temperature of the second reactor is 320-450 ℃;
the feeding weight airspeed is 0.5-20 h-1；
The reaction pressure is normal pressure.
Optionally, the reaction temperature of the first reactor is 240-350 ℃.
Optionally, the reaction temperature of the first reactor is 280-320 ℃.
Optionally, the upper limit of the reaction temperature of the first reactor is selected from 270 ℃, 280 ℃, 290 ℃, 300 ℃, 320 ℃, 330 ℃, 350 ℃ or 380 ℃; the lower limit is selected from 240 deg.C, 270 deg.C, 280 deg.C, 290 deg.C, 300 deg.C, 320 deg.C, 330 deg.C or 350 deg.C.
Optionally, the reaction temperature of the second reactor is 340-450 ℃.
Optionally, the reaction temperature of the second reactor is 320-380 ℃.
Optionally, the upper limit of the reaction temperature of the second reactor is selected from 340 ℃, 350 ℃, 360 ℃, 380 ℃, 390 ℃, 400 ℃, 420 ℃ or 450 ℃; the lower limit is selected from 320 deg.C, 340 deg.C, 350 deg.C, 360 deg.C, 380 deg.C, 390 deg.C, 400 deg.C or 420 deg.C.
Optionally, the feeding weight space velocity is 1-10 h-1。
Alternatively, the upper limit of the feed weight space velocity is selected from 1h-1、1.5h-1、2h-1、3h-1、5h-1、6h-1、10h-1Or 20h-1(ii) a The lower limit is selected from 0.5h-1、1h-1、1.5h-1、2h-1、3h-1、5h-1、6h-1Or 10h-1。
Optionally, the molar ratio of methanol to phenol is 6:1 to 1: 1;
the feed gas also comprises a diluent gas.
Optionally, the molar ratio of the dilution gas to phenol is 0.5 to 20.
Optionally, the diluent gas is selected from nitrogen or water vapor.
Alternatively, the upper limit of the molar ratio of methanol to phenol is selected from 2:1, 3:1, 4:1, 5:1, or 6: 1; the lower limit is selected from 1:1, 2:1, 3:1, 4:1 or 5: 1.
Alternatively, the upper limit of the dilution gas to phenol mole ratio is selected from 1, 2, 3, 4, 5, 6, 8, 10, 12, 15, 18, or 20; the lower limit is selected from 0.5, 1, 2, 3, 4, 5, 6, 8, 10, 12, 15 or 18.
Optionally, the method for producing 2, 6-xylenol by alkylating phenol comprises: taking phenol and methanol as raw materials, and adopting a two-stage method;
preheating raw material gas, mixing the preheated raw material gas with diluent gas in proportion, and continuously and sequentially passing through a reactor provided with an alkylation catalyst bed layer to carry out alkylation reaction to generate 2, 6-xylenol; the reaction temperature of the first reactor is 240-350 ℃, the reaction temperature of the second reactor is 340-450 ℃,the feeding weight airspeed is 0.5-20 h-1The reaction pressure is normal pressure; the alkylation catalyst consists of a molecular sieve and a binder and is prepared by modification treatment;
the modification treatment includes at least one of oxide modification and water vapor treatment.
As a specific embodiment, the method for producing the 2, 6-xylenol takes phenol and methanol as raw materials and adopts a two-stage method; preheating raw material gas, mixing the preheated raw material gas with diluent gas according to a certain molar ratio, and continuously and sequentially passing through a reactor filled with an alkylation catalyst bed layer to carry out alkylation reaction to generate 2, 6-xylenol; the reaction temperature of the first reactor is 240-350 ℃, the reaction temperature of the second reactor is 340-450 ℃, and the feeding weight space velocity is 0.5-20 h-1The reaction pressure is normal pressure; the alkylation catalyst consists of a molecular sieve and a binder and is prepared by oxide modification, water vapor treatment and acid treatment.
It should be further explained that in the preparation process, the characteristics of the catalyst structure and the number of acid sites are considered, the modification step and the percentage of the modifier in the catalyst are optimized and controlled, and silica, silica sol, diatomite, alumina and alumina sol are used during molding, so that the strength of the catalyst is increased after calcination. The oxide modification and the water vapor treatment enhance the hydrothermal stability of the catalyst, and the synergistic effect of the modification processes ensures that the catalyst has good catalytic performance and good strength, and can completely meet the industrial use requirements.
The preparation process of the catalyst is mixing and forming of the molecular sieve and the adhesive, and the forming mode can be spray drying or extrusion molding. The molecular sieve can be hydrogen type or ammonium type ZSM-5, MCM-22 and BETA molecular sieve. The weight content of the modified oxide is 1-15%. The temperature of the steam treatment is preferably 350-800 ℃, and the treatment is carried out for 0.5-10 hours by 100 percent steam.
The various modification methods of the catalyst are different depending on the acid strength of the parent molecular sieve and the density of different acid sites, and the desired catalyst is obtained by performing composite modification by the various modification methods used in the patent. For the molecular sieve precursor with smaller acid site density of the catalyst, the ideal acid strength can be obtained by adopting one or two modification methods of the patent. Therefore, the single modification method of various elements also belongs to the covered field of the patent. For example, a single modification such as a metal oxide modification or a steam treatment is within the scope of this patent.
The beneficial effects that this application can produce include:
(1) the application provides a method for producing 2, 6-xylenol by alkylating phenol and methanol, the catalyst has excellent performance and good stability, and the device is easy to realize large-scale production; compared with the traditional 2, 6-xylenol production process, the production process is pollution-free and is a new green and environment-friendly process technology;
(2) the method for producing the 2, 6-xylenol has the advantages of simple production flow and few reaction byproducts, and the 2, 6-xylenol product with the purity of more than 99.5 percent can be obtained through simple distillation.
Detailed Description
The present application will be described in detail with reference to examples, but the present application is not limited to these examples.
The raw materials in the examples of the present application were all purchased commercially, unless otherwise specified. The MCM-22 molecular sieve in the examples was synthesized according to the method in patent USP 4954325.
ZSM-5 molecular sieve, manufactured by catalyst factory of southern Kai university, and named NKF-5.
BETA molecular sieve, manufactured by catalyst factory of southern Kai university, and named NKF-6.
The ammonium formula exchange procedure is as follows: carrying out three exchanges of the molecular sieve in 0.5mol/L ammonium nitrate aqueous solution, wherein each exchange time is 4 hours, the solid-to-liquid ratio (wt) is 1:5, and the exchange temperature is 80 ℃; after the exchange, the plate was dried at 120 ℃ for 12 hours.
Hydrogen type molecular sieve: and roasting the ammonium molecular sieve for 6 hours at 600 ℃ to obtain the hydrogen molecular sieve.
The conversion, selectivity, in the examples of the present application were calculated as follows:
in the examples of the present application, the calculation of the phenol conversion and the 2, 6-xylenol selectivity was as follows:
