CN117777067A - Method for continuously preparing cyclic ether compound and catalyst used by same - Google Patents

Method for continuously preparing cyclic ether compound and catalyst used by same Download PDF

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Publication number
CN117777067A
CN117777067A CN202311629009.4A CN202311629009A CN117777067A CN 117777067 A CN117777067 A CN 117777067A CN 202311629009 A CN202311629009 A CN 202311629009A CN 117777067 A CN117777067 A CN 117777067A
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catalyst
reaction
acid
hours
carbon material
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刘晓然
蒋士峰
张少春
王喜成
牟新东
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Shanghai Suntian Technology Co ltd
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Shanghai Suntian Technology Co ltd
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Abstract

The application discloses a method for continuously preparing cyclic ether compounds, which takes alcohol raw materials as raw materials to continuously prepare the cyclic ether compounds through dehydration reaction, and a catalyst applied to the method, wherein the catalyst can stably run for a long time. The preparation method of the cyclic ether compound comprises the following steps: 1. adding a catalyst into a continuous reactor, heating to a catalyst activation temperature of 300-500 ℃, maintaining for 1-6h, and then adjusting to a reaction temperature of 160-450 ℃;2. the reaction pressure is kept at 0.1-3MPa, and the alcohol raw material is gasified and then is introduced into a continuous reactor for reaction. The method for continuously preparing the cyclic ether compound can continuously produce the cyclic ether compound, has high efficiency, and the used catalyst has good stability and long service life.

Description

Method for continuously preparing cyclic ether compound and catalyst used by same
Technical Field
The invention relates to the field of chemical synthesis, in particular to a method for continuously preparing cyclic ether compounds by dehydrating alcohol raw materials and a catalyst used in the method.
Background
The cyclic ether compound has very wide application in chemical industry, for example, tetrahydrofuran is the raw material of spandex synthesis reaction, can be used for producing PTMEG, and PTMEG is mainly used for producing elastic spandex fiber, in addition, tetrahydrofuran is also a solvent with excellent performance, has wide application in industries such as paint, printing ink and the like, can be used for producing intermediates such as tetrahydrothiophene, butyrolactone, pyrrolidone and the like in the industry as long as the industry is concerned, and is also an important solvent in the medical industry. 1, 4-dioxane, an excellent organic solvent, has wide application, can be used as a solvent for cellulose acetate and a plurality of resins, is mainly used as an extractant in the pharmaceutical industry, is used as a stripping agent in the coating and paint processes, is used as a solvent and a dispersing agent in the dye industry, and is used as a stabilizer in printing ink. 2, 5-dihydrofuran, 3, 4-dihydro-2H-hydropyran is a common synthetic intermediate, for example, 2, 5-dihydrofuran is a raw material for synthesizing anabasine insecticide dinotefuran, and 3, 4-dihydro-2H-pyran is a common organic synthetic hydroxyl protective agent. From these results, ether compounds are important chemicals for wide-ranging applications in the chemical industry.
The conventional method for synthesizing cyclic ether compounds is dehydration of alcohol, for example, the synthesis method of tetrahydrofuran is that 1, 4-butanediol is used as a raw material, and dehydration reaction is carried out under the action of an acid catalyst to obtain the cyclic ether compounds. The 1, 4-dioxane is prepared by taking ethylene glycol or diethylene glycol as a raw material and dehydrating under the action of an acid catalyst. The acid catalysts used are currently mainly various, and include liquid acids typified by sulfuric acid, phosphoric acid, and the like, heteropolyacids typified by phosphotungstic acid, phosphomolybdic acid, and the like, and solid acids. In contrast, the use of solid acid as a catalyst can solve the problems of equipment corrosion and acidic wastewater caused in the application process of liquid acid and heteropolyacid. The reactor type used is mainly two, one is batch kettle type reaction, and is characterized by simple operation, generally liquid acid is selected as catalyst, but because of batch operation, in many ether synthesis, the yield is lower due to carbon deposition caused by difficult control of residence time, and the production cost is high. The other is continuous reaction, represented by a fixed bed/fluidized bed reactor, and is characterized in that the reaction is continuously carried out, the residence time can be precisely controlled, high yield can be realized, and the safety is ensured. The metal oxide such as alumina, silica, molecular sieve and the like are generally adopted as catalysts, and the acid-base regulation of the surface of the catalyst is generally realized by controlling the content among the components of each oxide, and the conditions of the synthesis process such as crystallization temperature, crystallization time, aging temperature and the like. The method is difficult to accurately control the acidity and alkalinity of the catalyst surface, and a template agent with high toxicity is generally required to be used in the synthesis process of the catalyst. And carbon deposition generated in the reaction process is easy to block the surface of the active site of the catalyst, so that the catalyst is deactivated. Frequent regeneration of the catalyst increases the difficulty of operation to some extent. Therefore, how to improve the stability of the solid acid catalyst is a difficulty. The biomass charcoal material often can show different catalytic activity and product selectivity from the traditional metal oxide due to the abundant surface pore canal structure and the surface groups which can be conveniently regulated. In addition, the surface property of the material can be regulated and controlled by doping the carbon material with the hetero element. By means of the method, the catalyst can be rationally designed and controlled according to the active sites required by different reactions, and the high-efficiency catalyst for catalyzing the specific reaction with high selectivity can be synthesized in a targeted manner. The catalyst has the advantages of wide sources of raw materials, regeneration, easy regulation and control of the surface properties of the catalyst, no use of metal components and the like, and is receiving attention.
Disclosure of Invention
The present invention has been made in view of the above problems occurring in the prior art, and an object of the present invention is to provide a method for continuously producing cyclic ether compounds, which uses alcohol raw materials as raw materials to continuously dehydrate and produce ether compounds, and a catalyst for use in the method, which can be stably operated for a long period of time.
According to one aspect of the present invention, an object of the present invention is to provide a method for producing a cyclic ether compound, the method comprising the steps of:
step 1, adding a catalyst into a continuous reactor, heating to a catalyst activation temperature of 300-500 ℃, maintaining for 1-6h, and then adjusting to a reaction temperature of 160-450 ℃;
and 2, maintaining the reaction pressure at 0.1-3MPa, gasifying the alcohol raw material, and introducing the gasified alcohol raw material into a continuous reactor for reaction.
Optionally, the method according to the invention may further comprise: and 3, rectifying the reaction product obtained in the step 2 after condensation and gas-liquid separation.
In the step 1, the continuous reactor may be a fixed bed reactor or a fluidized bed reactor;
in the above step 1, the catalyst activation temperature may be 300 to 400 ℃ and the reaction temperature may be 250 to 400 ℃.
In the step 1, the reaction atmosphere may be one or more of nitrogen, helium and argon.
Preferably, in the above step 2, the reaction pressure is 0.1 to 1MPa.
Preferably, in the step 2, the alcohol raw material includes ethylene glycol, 1, 2-propylene glycol, 1, 4-butanediol, 1, 5-pentanediol, 1, 6-hexanediol, diethylene glycol, 1, 4-butylene glycol, and tetrahydrofurfuryl alcohol.
Preferably, in the above step 2, the reaction space velocity is 0.05 to 8 hours -1 Preferably 0.1-4h -1 。
According to another aspect of the present invention, it is another object of the present invention to provide a catalyst for a process for continuously preparing an ether compound by dehydration of an alcohol raw material, which is prepared by a process comprising the steps of:
1. pulverizing dried biomass raw materials by a pulverizer, adding the pulverized biomass raw materials and a solid acid catalyst into ball mill balls, grinding into fine powder of 200-400 meshes, adding the fine powder into a reaction kettle, adding distilled water, sealing the reaction kettle, heating to 150-250 ℃, carrying out hydrolysis reaction for 4-10h, cooling after reaction, decompressing, carrying out vacuum filtration, and concentrating filtrate by distillation to 20% of the original volume to obtain a concentrated solution;
2. adding an acid solution into the concentrated solution in the step 1 under intense stirring, adding chitosan after uniformly mixing, transferring into a hydrothermal kettle, carrying out hydrothermal treatment for 4-20h at 160-220 ℃, cooling, decompressing, respectively washing the obtained product with absolute ethyl alcohol and deionized water for 3 times, and drying at 110 ℃ for 12h to obtain a doped carbon material;
3. Adding alkali into the doped carbon material obtained in the step 2, stirring and mixing uniformly, placing in a tube furnace, heating to 300-700 ℃ under inert gas atmosphere for carbonization treatment for 4-20h, after carbonization,
cooling, washing the obtained material with distilled water until the filtrate is neutral, and drying at 110deg.C for 12 hr;
4. and (3) mixing the doped carbon material obtained in the step (3) with acid or oxidant, stirring uniformly, heating to 60-90 ℃ for 4-10h, cooling and filtering after the treatment is finished, washing the material with distilled water until the filtrate is neutral, and drying at 110 ℃ for 12h.
Preferably, the filter cake obtained after the reaction in the step 1 is filtered by suction contains the solid acid catalyst, the filter cake is roasted for 3-6 hours in the air atmosphere at 350-550 ℃ to remove organic matters, and the solid acid catalyst is obtained, and the obtained solid acid catalyst can be recycled.
In the step 1, the biomass material comprises one or more of corncob, corn stalk, sawdust, peanut shell and bamboo shoot.
Preferably, the biomass material in the step 1 comprises one or more of corncob, corn stalk and peanut shell.
More preferably, the biomass material in step 1 includes one or more of corncob and corn stalk.
In the step 1, the solid acid catalyst comprises one or more of silicon dioxide, gamma-alumina, zirconium dioxide, cerium dioxide, tungsten trioxide, niobium pentoxide, zeolite molecular sieve and ion exchange resin.
Preferably, the solid acid catalyst comprises one or more of silica, gamma-alumina, tungsten trioxide, niobium pentoxide, zeolite molecular sieves, ion exchange resins.
More preferably, the solid acid catalyst comprises one or more of gamma-alumina, zeolite molecular sieve, ion exchange resin.
Preferably, the zeolite molecular sieve comprises one or more of HZSM5, HZSM11, HY, hβ, HMOR, SAPO-34.
In the step 1, the mass ratio of the distilled water to the biomass raw material is 50:1-2:1.
Preferably, in the step 1, the mass ratio of the distilled water to the biomass raw material is 20:1-5:1.
In the step 1, the hydrolysis reaction temperature is 120-250 ℃.
Preferably, in the step 1, the hydrolysis reaction temperature is 150-220 ℃.
More preferably, in the step 1, the hydrolysis reaction temperature is 160 to 210 ℃.
In the step 1, the hydrolysis reaction time is 4-10h.
Preferably, in the step 1, the hydrolysis reaction time is 4 to 6 hours.
In the step 1, the mass concentration of the concentrated solution is 10% -30%.
Preferably, in the step 1, the mass concentration of the concentrated solution is 10% -20%.
In the step 2, the acid is one or more selected from formic acid, acetic acid, propionic acid and hydrochloric acid.
In the step 2, the mass concentration of the acid solution is 1% -30%.
Preferably, in the step 2, the mass concentration of the acid solution is 3% -10%.
In the step 2, the mass ratio of the acid solution to the concentrated solution is 1:1-10:1.
Preferably, in the step 2, the mass ratio of the acid solution to the concentrated solution is 1:1-5:1.
In the step 2, the mass ratio of the chitosan to the concentrated solution is 1:10-1:100.
In the step 2, the hydrothermal treatment temperature is 160-220 ℃.
Preferably, in the step 2, the hydrothermal treatment temperature is 180-210 ℃.
In the step 2, the hydrothermal treatment time is 4-20h.
Preferably, in the step 2, the hydrothermal treatment time is 5-10h.
In the step 3, the alkali is one or more selected from sodium hydroxide, potassium hydroxide, sodium methoxide, potassium methoxide, sodium ethoxide and potassium ethoxide.
In the step 3, the mass ratio of the alkali to the doped carbon material is 1:1-10:1.
Preferably, in the step 3, the mass ratio of the alkali to the doped carbon material is 1:1-5:1.
More preferably, in the step 3, the mass ratio of the alkali to the doped carbon material is 1:1-3:1.
In the step 3, the inert gas used in the carbonization process includes one or more of nitrogen, helium and argon.
Preferably, in the step 3, the inert gas used in the carbonization process includes one or more of nitrogen and argon.
In the step 4, the acid is one or more of sulfuric acid, hydrochloric acid, nitric acid, hydrofluoric acid and phosphoric acid. The oxidant is one or more of hydrogen peroxide (the mass concentration is 30 wt%) and sodium hypochlorite (the available chlorine is 6%).
In the step 4, the mass ratio of the acid to the doped carbon material is 1:1-10:1.
In the step 4, the mass ratio of the acid to the doped carbon material is 1:1-10:1; the mass ratio of the oxidant to the carbon material is 1:1-10:1.
In the step 4, the treatment temperature is 60-90 ℃.
In the step 4, the treatment time is 4-10 hours.
Advantageous effects
The method for continuously preparing the cyclic ether compound provided by the invention can continuously produce the cyclic ether compound, has high efficiency, and the catalyst used by the method has good stability and long service life.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following description will briefly explain the drawings needed in the embodiments or the prior art, and it is obvious that the drawings in the following description are some embodiments of the present invention and that other drawings can be obtained according to these drawings without inventive effort to a person skilled in the art.
FIG. 1 is a schematic view of a fixed bed reaction apparatus of a method for continuously producing a cyclic ether compound according to an embodiment of the present invention;
fig. 2 is a schematic view of a fluidized bed reaction apparatus for a method of continuously preparing a cyclic ether compound according to an embodiment of the present invention.
FIG. 3 is a graph showing the results of the reaction stability test in reaction example 1.
FIG. 4 is a graph showing the results of the reaction stability test in comparative example 1.
FIG. 5 is a graph showing the results of the reaction stability test in reaction example 2.
FIG. 6 is a graph showing the results of the reaction stability test in comparative example 2.
Fig. 7 is the results of ammonia temperature programmed desorption tests for the catalyst products of preparation example 6, comparative example 1 and comparative example 2.
Detailed Description
Hereinafter, preferred embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. Before the description, it should be understood that the terms used in the specification and the appended claims should not be construed as limited to general and dictionary meanings, but interpreted based on the meanings and concepts corresponding to technical aspects of the present invention on the basis of the principle that the inventor is allowed to define terms appropriately for the best explanation. Accordingly, the description herein is for the purpose of illustrating preferred examples only and is not intended to limit the scope of the invention, as it will be understood that other equivalent implementations and modifications may be made without departing from the spirit and scope of the invention.
In this document, the terms "comprising," "including," "having," "containing," or any other similar term are all open ended terms that are intended to cover a non-exclusive inclusion. For example, a composition or article comprising a plurality of elements is not limited to only those elements listed herein, but may include other elements not explicitly listed but typically inherent to such composition or article. In addition, unless explicitly stated to the contrary, the term "or" refers to an inclusive "or" and not to an exclusive "or". For example, any one of the following conditions satisfies the condition "a or B": a is true (or present) and B is false (or absent), a is false (or absent) and B is true (or present), a and B are both true (or present). Furthermore, the terms "comprising," "including," "having," "containing," and their derivatives, as used herein, are intended to be open ended terms that have been specifically disclosed and encompass both the closed and semi-closed terms, consisting of …, and consisting essentially of ….
All features or conditions defined herein in terms of numerical ranges or percentage ranges are for brevity and convenience only. Accordingly, the description of a numerical range or percentage range should be considered to cover and specifically disclose all possible sub-ranges and individual values within the range, particularly integer values. For example, a range description of "1 to 8" should be taken as having specifically disclosed all sub-ranges such as 1 to 7, 2 to 8, 2 to 6, 3 to 6, 4 to 8, 3 to 8, etc., particularly sub-ranges defined by all integer values, and should be taken as having specifically disclosed individual values such as 1, 2, 3, 4, 5, 6, 7, 8, etc. within the range. The foregoing explanation applies to all matters of the invention throughout its entirety unless indicated otherwise, whether or not the scope is broad.
If an amount or other numerical value or parameter is expressed as a range, preferred range, or a series of upper and lower limits, then it is understood that any range, whether or not separately disclosed, from any pair of the upper or preferred value for that range and the lower or preferred value for that range is specifically disclosed herein. Furthermore, where a range of numerical values is recited herein, unless otherwise stated, the range is intended to include the endpoints thereof, and all integers and fractions within the range.
In this context, numerical values should be understood to have the accuracy of the numerical significance of the numerical values provided that the objectives of the present invention are achieved. For example, the number 40.0 is understood to cover a range from 39.50 to 40.49.
For the purpose of illustrating the invention, parts irrelevant to the description are omitted from the drawings, and the same or similar parts are denoted by the same reference numerals throughout the specification.
In addition, the size and thickness of each component shown in the drawings are arbitrarily shown for convenience of explanation, and thus the present invention is not necessarily limited to those shown in the drawings.
Throughout the specification, when it is referred to that an element is "connected" to another element, it can be taken to include not only "direct connection" but also "indirect connection" between other elements. In addition, when an element is referred to as "comprising" a certain component, it is meant that the element may further comprise other components without excluding other components, unless explicitly stated to the contrary.
The following examples are merely illustrative of embodiments of the present invention and are not intended to limit the invention in any way, and those skilled in the art will appreciate that modifications may be made without departing from the spirit and scope of the invention.
In the step 2 of the preparation method of the cyclic ether compound, the reaction space velocity is 0.05 to 8h -1 Preferably 0.1-4h -1 . If the space velocity is too high, the conversion of the raw material decreases, and if the space velocity is too low, side reactions may occur.
The starting materials used in the present invention are commercially available and the methods and apparatus used are conventional in the art, except as specifically described herein.
In the following examples, 1, 4-butanediol, 1, 5-pentanediol, 1, 6-hexanediol, 1, 4-butenediol, tetrahydrofurfuryl alcohol, 2, 5-dimethyl-2, 5-hexanediol, sodium hydroxide, potassium hydroxide, formic acid, acetic acid, hydrochloric acid, sulfuric acid, nitric acid were purchased from the national pharmaceutical chemicals company, inc.; high purity nitrogen, high purity helium purchased from Qingdao de Hai Wei industry technologies Co., ltd; the corncob, the corn stalk and the peanut shell are purchased locally.
In the method for preparing the cyclic ether compound, the cyclic ether compound is obtained by taking alcohol raw materials as raw materials and carrying out dehydration reaction. The product obtained after separation in step 3 was filtered through a 0.22 μm filter and analyzed by Gas Chromatography (GC). Qualitative analysis of the low boiling point products was performed by gas chromatography-mass spectrometry (GC-MS) and standard GC retention time control, confirming that the reaction products were mainly cyclic ether products. The low boiling point substances were quantitatively determined by gas chromatography using Shimadzu-GC 2020, and quantitatively analyzed by comparison with the standard retention time and peak area size. The correlation calculation formula is as follows:
Wherein the flow unit of the alcohol raw material is g/min, and the unit of the catalyst dosage is g.
Fig. 1 is a schematic view of a fixed bed reaction apparatus of a method for continuously preparing a cyclic ether compound according to an embodiment of the present invention. Referring to fig. 1, wherein a reaction tube is filled with a catalyst according to the present application. First, a carrier gas is introduced into the reaction tube by controlling a flow rate through a mass flow meter to create a carrier gas atmosphere, after which a heating furnace may be heated to activate the catalyst. Then, maintaining the temperature of the reaction tube, feeding the alcohol raw material into the reaction tube through a feed pump, and reacting under the condition of carrier gas atmosphere and catalyst catalysis to generate a product containing the cyclic ether compound. And then condensing and gas-liquid separation are carried out, and the product of the cyclic ether compound can be obtained after collection.
Fig. 2 is a schematic view of a fluidized bed reaction apparatus for a method of continuously preparing a cyclic ether compound according to an embodiment of the present invention. Referring to fig. 2, wherein the reaction tube is filled with a catalyst according to the present application. First, a fluidizing gas is introduced into the reaction tube by controlling a flow rate by a mass flow meter to create a catalyst fluidized state, after which a heating furnace may be heated to activate the catalyst. Then, maintaining the temperature of the reaction tube, feeding the alcohol raw material into the reaction tube through a feed pump, and reacting under the conditions of fluidized gas atmosphere and catalyst catalysis to generate a product containing the cyclic ether compound. And then condensing and gas-liquid separation are carried out, and the product of the cyclic ether compound can be obtained after collection.
Examples
Preparation example 1
1. Pulverizing dried 150g corncob by a pulverizer, adding the pulverized corncob and 15g HZSM5 catalyst into a ball mill together, ball-grinding into 200-400 meshes of fine powder, adding the fine powder into a reaction kettle, adding 800ml of distilled water, sealing the reaction kettle, heating to 200 ℃, carrying out hydrolysis reaction for 6h, cooling after the reaction is finished, decompressing, carrying out suction filtration under reduced pressure, and concentrating the filtrate by distillation to obtain 143ml of concentrated solution.
2. Adding 200ml of formic acid solution with the mass percent concentration of 10% into the concentrated solution in the step 1 under vigorous stirring, adding 5g of chitosan, uniformly mixing, adding into a hydrothermal kettle, carrying out hydrothermal treatment at 180 ℃ for 10 hours, cooling, decompressing, respectively washing the obtained product with absolute ethyl alcohol and deionized water for 3 times, and drying at 110 ℃ for 12 hours to obtain the doped carbon material.
3. Taking 20g of the doped carbon material obtained in the step 2, adding 60g of potassium hydroxide into the carbon material, stirring and mixing uniformly, placing the mixture in a tube furnace, heating to 500 ℃ under inert gas atmosphere for carbonization treatment for 5 hours, cooling after carbonization, washing the obtained material with distilled water until filtrate is neutral, and drying at 110 ℃ for 12 hours.
4. 100ml of 20wt% nitric acid aqueous solution is added into 10g of the doped carbon material obtained in the step 3, the mixture is heated to 60 ℃ for 6 hours, after the treatment is finished, the temperature is reduced, the mixture is filtered, the material is washed to be neutral by distilled water, and the mixture is dried for 12 hours at 110 ℃. And cooling and taking out to obtain the catalyst 1.
Preparation example 2
1. Pulverizing dried 150g bamboo shoots by a pulverizer, adding the pulverized bamboo shoots and 15g HY catalyst into a ball mill together, ball-grinding into 200-400 meshes of fine powder, adding the fine powder into a reaction kettle, adding 800ml distilled water, sealing the reaction kettle, heating to 200 ℃, carrying out hydrolysis reaction for 6h, cooling after reaction, decompressing, carrying out vacuum filtration, and concentrating the filtrate by distillation to obtain 140ml concentrated solution.
2. Adding 200ml of acetic acid solution with the mass percent concentration of 10% into the concentrated solution in the step 1 under vigorous stirring, adding 5g of chitosan, uniformly mixing, adding into a hydrothermal kettle, carrying out hydrothermal treatment at 180 ℃ for 10 hours, cooling, decompressing, respectively washing the obtained product with absolute ethyl alcohol and deionized water for 3 times, and drying at 110 ℃ for 12 hours to obtain the doped carbon material.
3. Taking 20g of the doped carbon material obtained in the step 2, adding 60g of potassium hydroxide into the carbon material, stirring and mixing uniformly, placing the mixture in a tube furnace, heating to 600 ℃ under inert gas atmosphere for carbonization treatment for 5 hours, cooling after carbonization, washing the obtained material with distilled water until filtrate is neutral, and drying at 110 ℃ for 12 hours.
4. 100ml of 30wt% hydrochloric acid is added into 10g of the doped carbon material obtained in the step 3, the mixture is heated to 70 ℃ for 6 hours, after the treatment is finished, the temperature is reduced and the mixture is filtered, the material is washed with distilled water until the filtrate is neutral, and the mixture is dried for 12 hours at 110 ℃. And cooling and taking out to obtain the catalyst 2.
Preparation example 3
1. Pulverizing dried 300g peanut shell by a pulverizer, adding the pulverized peanut shell and 30g H beta catalyst into a ball mill together, ball-grinding into 200-400 meshes of fine powder, adding the fine powder into a reaction kettle, adding 1500ml of distilled water, sealing the reaction kettle, heating to 200 ℃, carrying out hydrolysis reaction for 6h, cooling after the reaction is finished, decompressing, carrying out vacuum filtration, and concentrating the filtrate by distillation to obtain 380ml of concentrated solution.
2. Adding 400ml of hydrochloric acid solution with the mass percent concentration of 10% into the concentrated solution in the step 1 under vigorous stirring, adding 10g of chitosan, uniformly mixing, adding into a hydrothermal kettle, carrying out hydrothermal treatment at 180 ℃ for 10 hours, cooling, decompressing, respectively washing the obtained product with absolute ethyl alcohol and deionized water for 3 times, and drying at 110 ℃ for 12 hours to obtain the doped carbon material.
3. Taking 20g of the doped carbon material obtained in the step 2, adding 60g of potassium hydroxide into the carbon material, stirring and mixing uniformly, placing the mixture in a tube furnace, heating to 600 ℃ under inert gas atmosphere for carbonization treatment for 5 hours, cooling after carbonization, washing the obtained material with distilled water until filtrate is neutral, and drying at 110 ℃ for 12 hours.
4. Adding 100ml of sodium hypochlorite aqueous solution (effective chlorine 6%) to 15g of the doped carbon material obtained in the step 3, heating to 60 ℃ for 6 hours, cooling and filtering after the treatment is finished, washing the material with distilled water until the filtrate is neutral, and drying at 110 ℃ for 12 hours. And cooling and taking out to obtain the catalyst 3.
Preparation example 4
1. Pulverizing dried 300g peanut shell by a pulverizer, adding the pulverized peanut shell and 30g H beta catalyst into a ball mill together, ball-grinding into 200-400 meshes of fine powder, adding the fine powder into a reaction kettle, adding 1500ml of distilled water, sealing the reaction kettle, heating to 200 ℃, carrying out hydrolysis reaction for 6h, cooling after the reaction is finished, decompressing, carrying out vacuum filtration, and concentrating the filtrate by distillation to obtain 369ml of concentrated solution.
2. 400ml of formic acid solution with the mass percentage concentration of 10% is added into the concentrated solution in the step 1 under vigorous stirring, 6g of chitosan is added into a hydrothermal kettle for uniformly mixing, the hydrothermal treatment is carried out for 10 hours at 180 ℃, the temperature is reduced, the pressure is relieved, the obtained product is respectively washed for 3 times by absolute ethyl alcohol and deionized water, and the product is dried for 12 hours at 110 ℃ to obtain the doped carbon material.
3. Taking 20g of the doped carbon material obtained in the step 2, adding 60g of potassium hydroxide into the carbon material, stirring and mixing uniformly, placing the mixture in a tube furnace, heating to 600 ℃ under inert gas atmosphere for carbonization treatment for 5 hours, cooling after carbonization, washing the obtained material with distilled water until filtrate is neutral, and drying at 110 ℃ for 12 hours.
4. Adding 100ml of 20wt% sulfuric acid aqueous solution into 18g of the doped carbon material obtained in the step 3, heating to 80 ℃ for 6 hours, cooling and filtering after the treatment is finished, washing the material with distilled water until the filtrate is neutral, and drying at 110 ℃ for 12 hours. And cooling and taking out to obtain the catalyst 4.
Preparation example 5
1. Crushing the dried 300g corn stalk with a crusher, mixing with 30g gamma-Al 2 O 3 Adding the catalyst into a ball mill together, ball-grinding into fine powder of 200-400 meshes, adding into a reaction kettle, adding 1500ml of distilled water, sealing the reaction kettle, heating to 200 ℃, carrying out hydrolysis reaction for 6h, cooling after the reaction is finished, decompressing, carrying out suction filtration under reduced pressure, and distilling and concentrating filtrate to obtain 369ml of concentrated solution.
2. Adding 400ml of acetic acid solution with the mass percent concentration of 10% into the concentrated solution in the step 1 under vigorous stirring, adding 4g of chitosan, uniformly mixing, adding into a hydrothermal kettle, carrying out hydrothermal treatment at 180 ℃ for 10 hours, cooling, decompressing, respectively washing the obtained product with absolute ethyl alcohol and deionized water for 3 times, and drying at 110 ℃ for 12 hours to obtain the doped carbon material.
3. Taking 20g of the doped carbon material obtained in the step 2, adding 60g of potassium hydroxide into the carbon material, stirring and mixing uniformly, placing the mixture in a tube furnace, heating to 600 ℃ under nitrogen gas atmosphere for carbonization treatment for 5 hours, cooling after carbonization, washing the obtained material with distilled water until filtrate is neutral, and drying at 110 ℃ for 12 hours.
4. Adding 100ml of 20wt% nitric acid aqueous solution into 15g of the doped carbon material obtained in the step 3, heating to 60 ℃ for 6 hours, cooling and filtering after the treatment is finished, washing the material with distilled water until the filtrate is neutral, and drying at 110 ℃ for 12 hours. And cooling and taking out to obtain the catalyst 5.
Preparation example 6
1. Pulverizing dried 300g corncob with pulverizer, mixing with 30g Nb 2 O 5 Adding the materials into a ball mill together, ball-grinding into fine powder of 200-400 meshes, adding the fine powder into a reaction kettle, adding 1500ml of distilled water, sealing the reaction kettle, heating to 200 ℃, carrying out hydrolysis reaction for 6h, cooling after the reaction is finished, decompressing, carrying out suction filtration under reduced pressure, and concentrating the filtrate by distillation to obtain 341ml of concentrated solution.
2. Adding 400ml of acetic acid solution with the mass percent concentration of 10% into the concentrated solution in the step 1 under vigorous stirring, adding 5g of chitosan, uniformly mixing, adding into a hydrothermal kettle, carrying out hydrothermal treatment at 180 ℃ for 10 hours, cooling, decompressing, respectively washing the obtained product with absolute ethyl alcohol and deionized water for 3 times, and drying at 110 ℃ for 12 hours to obtain the doped carbon material.
3. Taking 20g of the doped carbon material obtained in the step 2, adding 60g of sodium hydroxide into the carbon material, stirring and mixing uniformly, placing the mixture in a tube furnace, heating to 600 ℃ under nitrogen gas atmosphere for carbonization treatment for 5 hours, cooling after carbonization, washing the obtained material with distilled water until filtrate is neutral, and drying at 110 ℃ for 12 hours.
4. Adding 100ml of 40wt% sulfuric acid aqueous solution into 15g of the doped carbon material obtained in the step 3, heating to 60 ℃ for 6 hours, cooling and filtering after the treatment is finished, washing the material with distilled water until the filtrate is neutral, and drying at 110 ℃ for 12 hours. And cooling and taking out to obtain the catalyst 6.
Comparative example 1
1. Pulverizing dried 300g corncob with pulverizer, mixing with 30g Nb 2 O 5 Adding into a ball mill together, grinding into 200-400 mesh fine powder, and adding into a reaction kettle1500ml of distilled water is added, the reaction kettle is sealed and then heated to 200 ℃, hydrolysis reaction is carried out for 6 hours, after the reaction is finished, the temperature is reduced, decompression and suction filtration are carried out, and 341ml of concentrated solution is obtained by distillation and concentration of filtrate.
2. Adding 400ml of acetic acid solution with the mass percent concentration of 10% into the concentrated solution in the step 1 under vigorous stirring, adding into a hydrothermal kettle after uniformly mixing, carrying out hydrothermal treatment at 180 ℃ for 10 hours, cooling, decompressing, respectively washing the obtained product with absolute ethyl alcohol and deionized water for 3 times, and drying at 110 ℃ for 12 hours to obtain the doped carbon material.
3. Taking 20g of the doped carbon material obtained in the step 2, adding 60g of sodium hydroxide into the carbon material, stirring and mixing uniformly, placing the mixture in a tube furnace, heating to 600 ℃ under nitrogen gas atmosphere for carbonization treatment for 5 hours, cooling after carbonization, washing the obtained material with distilled water until filtrate is neutral, and drying at 110 ℃ for 12 hours.
4. Adding 100ml of 40wt% sulfuric acid aqueous solution into 15g of the doped carbon material obtained in the step 3, heating to 60 ℃ for 6 hours, cooling and filtering after the treatment is finished, washing the material with distilled water until the filtrate is neutral, and drying at 110 ℃ for 12 hours. And taking out the catalyst after cooling to obtain the comparative catalyst 1.
Comparative example 2
1. Pulverizing dried 300g corncob with pulverizer, mixing with 30g Nb 2 O 5 Adding the materials into a ball mill together, ball-grinding into fine powder of 200-400 meshes, adding the fine powder into a reaction kettle, adding 1500ml of distilled water, sealing the reaction kettle, heating to 200 ℃, carrying out hydrolysis reaction for 6h, cooling after the reaction is finished, decompressing, carrying out suction filtration under reduced pressure, and concentrating the filtrate by distillation to obtain 341ml of concentrated solution.
2. Adding 400ml of acetic acid solution with the mass percent concentration of 10% into the concentrated solution in the step 1 under vigorous stirring, adding into a hydrothermal kettle after uniformly mixing, carrying out hydrothermal treatment at 180 ℃ for 10 hours, cooling, decompressing, respectively washing the obtained product with absolute ethyl alcohol and deionized water for 3 times, and drying at 110 ℃ for 12 hours to obtain the doped carbon material.
3. And (2) adding 60g of sodium hydroxide into 20g of the doped carbon material obtained in the step (2), stirring and mixing uniformly, placing the mixture in a tube furnace, heating to 600 ℃ under nitrogen gas atmosphere for carbonization treatment for 5 hours, cooling after carbonization, washing the obtained material with distilled water until filtrate is neutral, and drying at 110 ℃ for 12 hours to obtain the comparative catalyst 2.
Characterization of the catalyst product
1. Catalyst elemental analysis
Table 1 below shows the results of elemental analysis of the catalyst products prepared in preparation examples 1-6 and comparative examples 1-2.
Table 1: catalyst elemental analysis
Carbon (wt%) Nitrogen (wt%) Oxygen (wt%) Hydrogen (wt%)
Preparation example 1 79.3 10.6 3.7 1.9
Preparation example 2 78.2 10.0 4.3 1.1
Preparation example 3 78.5 9.2 3.3 1.3
Preparation example 4 77.3 10.1 3.2 1.9
Preparation example 5 79.1 8.3 3.3 1.8
Preparation example 6 80.6 9.3 3.2 1.4
Comparative example 1 84.6 1.7 5.2 1.9
Comparative example 2 81.6 9.0 2.9 1.1
As shown by the element analysis result, in the synthesis process of the carbon-based catalyst, nitrogen element in chitosan can be well doped into the carbon material, and the nitrogen content in the synthesized doped carbon material is about 10 wt%. In comparative example 1, in which chitosan was not added, the obtained carbon material had a low nitrogen content, indicating that the above synthesis method can dope nitrogen element in chitosan into the carbon material.
2. Quantitative detection of catalyst surface groups
The Boehm titration method is adopted to quantitatively detect the surface groups of the prepared catalyst, and the method comprises the following steps:
preparation:
1. deionized water is boiled for a few minutes in an oil bath at 160 ℃ and is stored in a sealed manner.
2. Preparing NaOH, HCl and Na 2 CO 3 ，NaHCO 3 Standard titration solution, the concentration of standard titration solution is determined.
Boehm titration:
1. about 3 samples were weighed and placed in 3 conical flasks (made of plastic and thoroughly dried) with stoppers, and 50mL of 0.05mol/L NaOH and Na were added to each flask 2 CO 3 ，NaHCO 3 A solution.
2. The flask was placed on a shaker for 4h and then allowed to stand at room temperature for 24h (generally the longer the time the better).
3. The active carbon slurry is filtered once by suction, and 20mL of filtrate is taken.
4. To 20mL of the filtrate was added 20mL of 0.05mol/L hydrochloric acid (Na addition 2 CO 3 Adding 40mL of hydrochloric acid and Na 2 CO 3 ，NaHCO 3 Adding hydrochloric acid into the filtrate, and boiling again to remove CO 2 )。
5. Back-titrating excess acid to reddish solution with 0.05mol/L standard NaOH titration solution using phenolphthalein as indicator
Alkali consumption:
a＝(V*CNaOH+20*C0-20*CHCl)*2.5/M(NaOH,NaHCO 3 calculation formula
a＝(V*CNaOH+20*C0-40*CHCl)*2.5/M(Na 2 CO 3 Calculation formula
Description of the calculation formula:
the concentration C0 in the formula is based on the equivalent concentration due to Na 2 CO 3 For the aprotic base, calculate Na 2 CO 3 In the case where C0 is Na 2 CO 3 Molar concentration of (2).
V is the volume of NaOH consumed, C0 is the concentration of alkali liquor added, CHCl is the concentration of hydrochloric acid solution used, and M is the mass of active carbon.
And (3) calculating:
NaHCO for carboxyl number 3 Consumption of aNaHCO 3 To represent; the amount of lactone groups is Na 2 CO 3 And NaHCO 3 Difference of consumption a Na of (a) 2 CO 3 -a NaHCO 3 To represent; the phenolic hydroxyl group is obtained by NaOH and Na 2 CO 3 Difference in consumption of aNaOH-aNa 2 CO 3 To represent
Table 2 below shows the results of analysis of the number of surface groups of the catalyst products prepared in preparation examples 1 to 6 and comparative examples 1 to 2.
Table 2: number of surface groups of the catalyst
As shown in the table 2, the doped carbon material catalyst synthesized by the invention has rich surface groups, and the amounts of carboxyl, lactone and phenolic hydroxyl on the surface of the catalyst material are about 0.5-0.6mmol/g and about 0.6-0.7mmol/g and about 0.1mmol/g respectively. In comparative example 2, which did not use acid or oxidizing agent treatment, the amounts of the surface groups carboxyl group, lactone group, and phenolic hydroxyl group in the obtained carbon material were 0.33mmol/g,0.21mmol/g, and 0.06mmol/g, respectively, which were significantly reduced compared to the other carbon materials described in the present patent application, indicating that the acid/oxidizing agent treatment can greatly enrich the number of groups on the surface of the carbon material.
3. Detection of ammonia gas temperature programming desorption of catalyst
NH of catalyst product 3 TPD characterization was performed on an AutoChem 2920 chemisorber from Micromeritics. The specific experimental steps are as follows: 0.1g of the sample is put into a U-shaped quartz tube, purged for 2 hours at 150 ℃ in Ar gas atmosphere, then cooled to 100 ℃ and adsorbed with 5wt% NH3/Ar mixed gas for 2 hours at 100 ℃. Then switching to purging the physically adsorbed ammonia gas for 1h under Ar atmosphere, leveling the base line, and then heating to 800 ℃ at a heating rate of 10 ℃/min. Recording NH Using TCD Detector 3 A signal. The results are shown in FIG. 7.
As can be seen from fig. 7, NH for catalyst 6 and comparative catalyst 2 3 The TPD comparison results are shown in the above graph, from which it is clear that the comparison catalyst 1 has a significant NH at 200 DEG C 3 The desorption peak shows a certain weak acidic site. Comparative catalyst 2 had NH at around 200 ℃ 3 The presence of a desorption peak outside the desorption peak at a higher temperature (around 440 ℃) shows a stronger acidity. While catalyst 6 has a stronger NH at 230 DEG C 3 The desorption peak, thus, shows that the acid or oxidant treatment can obviously enhance the acidity of the catalyst surface, and NH 3 The desorption temperature of the catalyst is obviously increased, which means that the acid strength of the catalyst is stronger and the acid quantity is higher. The result is consistent with the result of the content of the surface groups of the catalyst obtained by the Boehm titration test, and shows that the acid/oxidant treatment can obviously improve the number of the groups on the surface of the catalyst, so that the acidity of the surface of the catalyst can be enhanced.
Reaction example 1
1. 2g of shaped catalyst 1 (20-40 mesh) were introduced into a fixed bed reactor, in N 2 Heating to 400 ℃ under the atmosphere, maintaining for 3 hours, and then cooling to 250 ℃.
2. 1, 4-butene diol was fed over 0.8h -1 Is introduced into the reactor for reaction.
3. After condensation and gas-liquid separation, the conversion rate of 1, 4-butylene glycol is 99.1%, the selectivity of 2, 5-dihydrofuran is 91%, the selectivity of crotonaldehyde is 6.1%, and the material balance of the reactor is 99% by GC detection. The catalyst can stably run for more than 700 hours, the activity is hardly changed, the conversion rate is always maintained to be more than 99%, and the selectivity of 2, 5-dihydrofuran is maintained to be 89-93%.
Comparative example 1
1. 2g of shaped comparative example 1 (20-40 mesh) were charged in a fixed bed reactor, N 2 Heating to 400 ℃ under the atmosphere, maintaining for 3 hours, and then cooling to 250 ℃.
2.1, 4-butene diol was fed over 0.8h -1 Is introduced into the reactor for reaction.
3. After condensation and gas-liquid separation, the conversion rate of 1, 4-butylene glycol is 99.0%, the selectivity of 2, 5-dihydrofuran is 90.3%, the selectivity of crotonaldehyde is 5.7%, and the balance of reactor materials is 99% by GC detection. The catalyst showed a significant activity drop at 60 hours of operation and a conversion to 68% at 200 hours.
Reaction example 2
1. 2g of shaped catalyst 2 (20-40 mesh) were introduced into a fixed bed reactor, in N 2 Heating to 400 ℃ under the atmosphere, maintaining for 3 hours, and then cooling to 350 ℃.
2. Tetrahydrofurfuryl alcohol is reacted for 0.5h -1 Is introduced into the reactor for reaction.
3. After condensation and gas-liquid separation, the conversion rate of tetrahydrofurfuryl alcohol is 99.8%, the selectivity of 3, 4-dihydro-2H-pyrane is 92.6%, the selectivity of tetrahydropyran is 2.1%, the balance of reactor materials is 96%, the activity of the catalyst can be hardly changed after the catalyst is stably operated for 370 hours, the conversion rate is always maintained to be more than 99%, and the selectivity of 3, 4-dihydro-2H-pyrane is maintained to be 90-93%.
Comparative example 2
1. 2g of shaped comparative example 2 (20-40 mesh) were charged in a fixed bed reactor, N 2 Heating to 400 ℃ under the atmosphere, maintaining for 3 hours, and then cooling to 350 ℃.
2. Tetrahydrofurfuryl alcohol is reacted for 0.5h -1 Is introduced into the reactor for reaction.
3. After condensation and gas-liquid separation, the conversion rate of tetrahydrofurfuryl alcohol is 99.8%, the selectivity of 3, 4-dihydro-2H-pyrane is 90.6%, the selectivity of tetrahydropyran is 3.3%, and the material balance of the reactor is 96%. The catalyst has obvious activity reduction after 30 hours of operation, the conversion rate is reduced from more than 99% to 90%, and the conversion rate is reduced to 61% after 106 hours.
Reaction example 3
1. 2g of shaped catalyst 1 (20-40 mesh) were introduced into a fixed bed reactor, in N 2 Heating to 400 ℃ under the atmosphere, maintaining for 3 hours, and then cooling to 250 ℃.
2. 1, 4-butanediol raw material is introduced into a reactor for reaction at a space velocity of 0.7h < -1 >.
3. After condensation and gas-liquid separation, the conversion rate of 1, 4-butanediol is 99.3 percent, the tetrahydrofuran selectivity is 97 percent, and the material balance of the reactor is 98 percent.
Reaction example 4
1. 2g of shaped catalyst 3 (20-40 mesh) were introduced into a fixed bed reactor, in N 2 Heating to 400 ℃ under the atmosphere, maintaining for 3 hours, and then cooling to 270 ℃.
2. 1, 5-pentanediol was introduced into the reactor at a space velocity of 0.5h-1 to carry out the reaction.
3. After condensation and gas-liquid separation, the conversion rate of 1, 5-pentanediol is 99.9 percent, the selectivity of tetrahydropyran is 97.2 percent, and the material balance of the reactor is 98 percent.
Reaction example 5
1. 2g of shaped catalyst 4 (20-40 mesh) were introduced into a fixed bed reactor, in N 2 Heating to 400 ℃ under the atmosphere, maintaining for 3 hours, and then cooling to 200 ℃.
2. Diethylene glycol was fed to the reactor at a space velocity of 0.3h-1 for reaction.
3. After condensation and gas-liquid separation, the conversion rate of diethylene glycol is 99.9%, the selectivity of 1, 4-dioxane is 96.2%, the selectivity of methyl-1, 3-dioxolane is 1.7%, the selectivity of acetaldehyde is 0.8%, and the balance of reactor materials is 98%.
Reaction example 6
1. Adding 2g of formed catalyst into a fixed bed reactor to obtain a catalyst20-40 mesh), in N 2 Heating to 400 ℃ under the atmosphere, maintaining for 3 hours, and then cooling to 300 ℃.
2. 1, 6-hexanediol (in the molten state) was fed into the reactor at a space velocity of 0.1h-1 for the reaction.
3. After condensation and gas-liquid separation, the conversion rate of 1, 6-hexanediol is 83.3% by GC detection, the selectivity of the oxacyclohexane is 97.8%, and the material balance of the reactor is 99%.
Reaction example 7
1. 2g of shaped catalyst 6 (20-40 mesh) were introduced into a fixed bed reactor, in N 2 Heating to 400 ℃ under the atmosphere, maintaining for 3 hours, and then cooling to 200 ℃.
2. Ethylene glycol was introduced into the reactor at a space velocity of 0.5h-1 to carry out the reaction.
3. The conversion rate of glycol is 99.3% after condensation and gas-liquid separation, the selectivity of 1, 4-dioxane is 98.8%, and the material balance of the reactor is 99%.
Reaction example 8
1. 2g of shaped catalyst 6 (20-40 mesh) were introduced into a fixed bed reactor, in N 2 Heating to 400 ℃ under the atmosphere, maintaining for 3 hours, and then cooling to 250 ℃.
2. 1, 2-propanediol was introduced into the reactor at a space velocity of 0.5h-1 to effect the reaction.
3. After condensation and gas-liquid separation, the conversion rate of 1, 2-propanediol is 99.3%, the selectivity of 2, 5-dimethyl-1, 4-dioxane is 98.8%, and the material balance of the reactor is 99%.
Reaction example 9
1. 230g of catalyst 1 (100-150 mesh) were charged into a fluidized bed reactor, and introduced into a reactor under N 2 Heating to 400 ℃ under the atmosphere for 3 hours, then cooling to 250 ℃ and keeping the fluidization gas speed at 2L/min.
2. 1, 4-butylene glycol was introduced into the reactor at a space velocity of 0.5h-1 to carry out the reaction.
3. After condensation and gas-liquid separation, the conversion rate of 1, 4-butylene glycol is 99.0% by GC detection, the selectivity of 2, 5-dihydrofuran is 98.1%, and the material balance of the reactor is 91%.
Reaction example 10
1. 200g of catalyst 2 (100-150 mesh) were charged into a fluidized bed reactor, and introduced into a reactor vessel under N 2 Heating to 400 ℃ under the atmosphere for 3 hours, then cooling to 220 ℃ and keeping the fluidization gas speed at 2L/min.
2. Diethylene glycol was fed to the reactor at a space velocity of 0.5h-1 for reaction.
3. The conversion rate of diethylene glycol is 99.4% after condensation and gas-liquid separation, the selectivity of 2, 5-dihydrofuran is 97.8%, and the material balance of the reactor is 93%.
Reaction example 11
1. 200g of catalyst 3 (100-150 mesh) were charged into a fluidized bed reactor, and introduced into a reactor vessel under N 2 Heating to 400 ℃ under the atmosphere for 3 hours, then cooling to 200 ℃ and keeping the fluidization gas speed at 2L/min.
2. Ethylene glycol was introduced into the reactor at a space velocity of 0.5h-1 to carry out the reaction.
3. After condensation and gas-liquid separation, the conversion rate of diethylene glycol is 99.8%, the selectivity of 2, 5-dihydrofuran is 96.3% and the material balance of the reactor is 91% by GC detection.
Reaction example 12
1. 2g of shaped catalyst 6 (20-40 mesh) were introduced into a fixed bed reactor, in N 2 Heating to 400 ℃ under the atmosphere, maintaining for 3 hours, and then cooling to 110 ℃.
2. 2, 5-dimethyl-2, 5-hexanediol was introduced into the reactor at a space velocity of 0.3h-1 to effect a reaction.
3. After condensation and gas-liquid separation, the conversion rate of 2, 5-dimethyl-2, 5-hexanediol is 99.3 percent, the selectivity of tetramethyl tetrahydrofuran is 96.8 percent, and the material balance of the reactor is 99 percent.
The foregoing is merely illustrative of the present invention, and the present invention is not limited thereto, and any person skilled in the art will readily recognize that variations or substitutions are within the scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.

Claims (10)

1. A method for continuously preparing a cyclic ether compound, comprising the steps of:
step 1, adding a catalyst into a continuous reactor, heating to a catalyst activation temperature of 300-500 ℃, maintaining for 1-6h, and then adjusting to a reaction temperature of 160-450 ℃;
and 2, maintaining the reaction pressure at 0.1-3MPa, gasifying the alcohol raw material, and introducing the gasified alcohol raw material into a continuous reactor for reaction.
2. The method for continuously producing a cyclic ether compound according to claim 1, further comprising: and 3, rectifying the reaction product obtained in the step 2 after condensation and gas-liquid separation.
3. The method for continuously producing a cyclic ether compound according to claim 1, wherein preferably, in the step 1, the continuous reactor may be a fixed bed reactor or a fluidized bed reactor;
preferably, in the step 1, the catalyst activation temperature may be 300 to 400 ℃ and the reaction temperature may be 250 to 400 ℃;
preferably, in the step 1, the reaction atmosphere may be one or more of nitrogen, helium and argon.
4. The method for continuously producing a cyclic ether compound according to claim 1, wherein preferably, in the step 2, the reaction pressure is 0.1 to 1MPa;
preferably, in the step 2, the alcohol raw material comprises ethylene glycol, 1, 2-propylene glycol, 1, 4-butanediol, 1, 5-pentanediol, 1, 6-hexanediol, diethylene glycol, 1, 4-butylene glycol and tetrahydrofurfuryl alcohol;
preferably, in the step 2, the reaction space velocity is 0.05 to 8 hours -1 Preferably 0.1-4h -1 。
5. A catalyst for use in the production process for continuously producing a cyclic ether compound according to any one of claims 1 to 4, which is produced by a process comprising the steps of:
1) Pulverizing dried biomass raw materials by a pulverizer, adding the pulverized biomass raw materials and a solid acid catalyst into ball mill balls, grinding into fine powder of 200-400 meshes, adding the fine powder into a reaction kettle, adding distilled water, sealing the reaction kettle, heating to 150-250 ℃, carrying out hydrolysis reaction for 4-10h, cooling after reaction, decompressing, carrying out vacuum filtration, and concentrating filtrate by distillation to 20% of the original volume to obtain a concentrated solution;
2) Adding an acid solution into the concentrated solution in the step 1 under intense stirring, adding chitosan after uniformly mixing, transferring into a hydrothermal kettle, carrying out hydrothermal treatment for 4-20h at 160-220 ℃, cooling, decompressing, respectively washing the obtained product with absolute ethyl alcohol and deionized water for 3 times, and drying at 110 ℃ for 12h to obtain a doped carbon material;
3) Adding alkali into the doped carbon material obtained in the step 2, stirring and mixing uniformly, placing the mixture in a tube furnace, heating to 300-700 ℃ under inert gas atmosphere for carbonization treatment for 4-20h, cooling after carbonization, washing the obtained material with distilled water until filtrate is neutral, and drying at 110 ℃ for 12h;
4) And (3) mixing the doped carbon material obtained in the step (3) with acid or oxidant, stirring uniformly, heating to 60-90 ℃ for 4-10h, cooling and filtering after the treatment is finished, washing the material with distilled water until the filtrate is neutral, and drying at 110 ℃ for 12h.
6. The catalyst according to claim 5, wherein preferably, the filter cake obtained by suction filtration after the reaction in step 1) contains the solid acid catalyst, the filter cake is baked for 3-6 hours in an air atmosphere at 350-550 ℃ to remove organic matters, and the obtained solid acid catalyst can be recycled.
7. The catalyst of claim 5, wherein in step 1, the biomass material comprises one or more of corncob, corn stover, sawdust, peanut shells, bamboo shoots;
preferably, the biomass material in the step 1 comprises one or more of corncob, corn stalk and peanut shell;
more preferably, the biomass material in the step 1 comprises one or more of corncob and corn straw;
preferably, in the step 1, the solid acid catalyst comprises one or more of silica, gamma-alumina, zirconium dioxide, cerium dioxide, tungsten trioxide, niobium pentoxide, zeolite molecular sieve, and ion exchange resin;
more preferably, the solid acid catalyst comprises one or more of silica, gamma-alumina, tungsten trioxide, niobium pentoxide, zeolite molecular sieves, ion exchange resins;
More preferably, the solid acid catalyst comprises one or more of gamma-alumina, zeolite molecular sieve, ion exchange resin;
more preferably, the zeolite molecular sieve comprises one or more of HZSM5, HZSM11, HY, hβ, HMOR, SAPO-34;
preferably, in the step 1, the mass ratio of the distilled water to the biomass raw material is 50:1-2:1;
more preferably, in the step 1, the mass ratio of the distilled water to the biomass raw material is 20:1-5:1;
preferably, in the step 1, the hydrolysis reaction temperature is 120-250 ℃;
more preferably, in the step 1, the hydrolysis reaction temperature is 150-220 ℃;
more preferably, in the step 1, the hydrolysis reaction temperature is 160-210 ℃;
preferably, in the step 1, the hydrolysis reaction time is 4-10 hours;
more preferably, in the step 1, the hydrolysis reaction time is 4 to 6 hours;
preferably, in the step 1, the mass concentration of the concentrated solution is 10% -30%;
more preferably, in the step 1, the mass concentration of the concentrated solution is 10% -20%.
8. The catalyst according to claim 5, wherein in step 2, the acid is selected from one or more of formic acid, acetic acid, propionic acid, hydrochloric acid;
Preferably, in the step 2, the mass concentration of the acid solution is 1% -30%;
more preferably, in the step 2, the mass concentration of the acid solution is 3% -10%;
preferably, in the step 2, the mass ratio of the acid solution to the concentrated solution is 1:1-10:1;
more preferably, in the step 2, the mass ratio of the acid solution to the concentrated solution is 1:1-5:1;
preferably, in the step 2, the mass ratio of the chitosan to the concentrated solution is 1:10-1:100;
preferably, in the step 2, the hydrothermal treatment temperature is 160-220 ℃;
more preferably, in the step 2, the hydrothermal treatment temperature is 180-210 ℃;
preferably, in the step 2, the hydrothermal treatment time is 4-20h;
more preferably, in the step 2, the hydrothermal treatment time is 5 to 10 hours.
In the step 3, the alkali is one or more selected from sodium hydroxide, potassium hydroxide, sodium methoxide, potassium methoxide, sodium ethoxide and potassium ethoxide.
9. The catalyst of claim 5, wherein in step 3, the mass ratio of the base to the doped carbon material is 1:1 to 10:1;
more preferably, in the step 3, the mass ratio of the alkali to the doped carbon material is 1:1-5:1;
More preferably, in the step 3, the mass ratio of the alkali to the doped carbon material is 1:1-3:1;
preferably, in the step 3, the inert gas used in the carbonization process includes one or more of nitrogen, helium and argon;
more preferably, in the step 3, the inert gas used in the carbonization process includes one or more of nitrogen and argon.
10. The catalyst of claim 5, wherein in step 4, the acid is one or more of sulfuric acid, hydrochloric acid, nitric acid, hydrofluoric acid, phosphoric acid. The oxidant is one or more of hydrogen peroxide (the mass concentration is 30 wt%), and sodium hypochlorite (the available chlorine is 6 percent);
preferably, in the step 4, the mass ratio of the acid to the doped carbon material is 1:1-10:1;
preferably, in the step 4, the mass ratio of the acid to the doped carbon material is 1:1-10:1;
preferably, the mass ratio of the oxidant to the doped carbon material is 1:1-10:1;
preferably, in the step 4, the treatment temperature is 60-90 ℃;
preferably, in the step 4, the treatment time is 4-10 hours.
CN202311629009.4A 2023-11-30 2023-11-30 Method for continuously preparing cyclic ether compound and catalyst used by same Pending CN117777067A (en)

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