CN114289040B - Catalyst for gas phase synthesis of dimethyl carbonate and preparation method thereof - Google Patents
Catalyst for gas phase synthesis of dimethyl carbonate and preparation method thereof Download PDFInfo
- Publication number
- CN114289040B CN114289040B CN202111653371.6A CN202111653371A CN114289040B CN 114289040 B CN114289040 B CN 114289040B CN 202111653371 A CN202111653371 A CN 202111653371A CN 114289040 B CN114289040 B CN 114289040B
- Authority
- CN
- China
- Prior art keywords
- perchlorate
- molybdate
- mass
- catalyst
- carrier
- 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.)
- Active
Links
Landscapes
- Catalysts (AREA)
Abstract
The invention discloses a catalyst for synthesizing dimethyl carbonate by gas phase, wherein a carrier comprises titanium dioxide, pseudo-boehmite and an auxiliary agent, the mass ratio of the titanium dioxide to the pseudo-boehmite is 1 (1-10), and the auxiliary agent is 0.1% -1% of the sum of the mass of the titanium dioxide and the pseudo-boehmite; the active components comprise soluble palladium salt, perchlorate and zirconium oxychloride, wherein the mass of the soluble palladium salt is 0.1-1% of the mass of the carrier, the molar ratio of the perchlorate to the soluble palladium salt is (1-20): 1, the mass of the zirconium oxychloride is 0.1-1% of the mass of the carrier, and the auxiliary agent is molybdate. The invention also discloses a preparation method of the catalyst for synthesizing the dimethyl carbonate by gas phase, and the prepared catalyst has higher conversion rate and selectivity and longer service life.
Description
Technical Field
The invention belongs to the technical field of chemical technology, and particularly relates to a catalyst for gas-phase synthesis of dimethyl carbonate and a preparation method thereof.
Background
Dimethyl carbonate (DMC) is an environment-friendly chemical raw material with low toxicity and environmental protection meeting the requirements of modern clean process, has good DMC reaction activity, and is widely applied to the fields of pesticides, medicines, plastics, dyes, electronic chemicals, food additives, color imaging and the like. In recent years, along with the rapid progress of lithium battery technology in China, the DMC consumption is greatly increased, and the supply is not required.
The current production process routes mainly comprise a phosgene method, an ester exchange method, a urea alcoholysis method and a methanol oxidative carbonylation method, and a methyl nitrite gas-phase carbonylation method. The phosgene method mainly uses highly toxic phosgene as raw material, and the method is a obsolete process for seriously corroding equipment. The transesterification method uses ethylene oxide or ethylene (propylene) carbonate as raw materials, has higher production cost and lacks market competitiveness. The DMC synthesis reaction by the urea alcoholysis method is carried out under the conditions of high pressure and a catalyst, and the catalyst is expensive. The methanol oxidative carbonylation method has low raw material cost and high product selectivity, but the catalyst is easy to deactivate. The methyl nitrite vapor phase carbonylation method has the advantages of cyclic utilization of products, high atom utilization rate and low production cost, and is very suitable for industrialization.
Patent CN 110844918A provides a Y-type molecular sieve synthesized DMC catalyst, the Y-type molecular sieve is synthesized by adopting a hydrothermal method and a microwave-assisted crystallization method, and the Y-type molecular sieve is obtained by preparing a guiding agent, regulating and controlling the composition of a titanium source and a phosphorus source to a mother solution, performing a crystallization reaction after microwave pre-crystallization treatment, and obtaining the Y-type molecular sieve, although the performance is better and chlorine-free, from the viewpoint of preparation, the microwave crystallization process is very limited, the requirement on preparation equipment is high, the crystallization failure rate is difficult to control, and the large-scale production is difficult to realize, so that the price of the catalyst is high, and the production cost and the production period are increased.
Patent CN 111018710A provides a novel synthesis method of strong alkaline ionic liquid and a novel embedded riveting type immobilization method of the ionic liquid, the prepared homogeneous phase catalyst and heterogeneous catalyst are used for catalyzing and synthesizing methyl carbonate, the ionic liquid has good activity on the exchange of ethylene carbonate and methyl alcohol ester, the ionic liquid is a homogeneous catalyst hopefully replacing the traditional catalyst, but the synthesis process of the ionic liquid is complex, an organic solvent is needed in the synthesis process, waste water can be generated, on one hand, the production cost of the ionic liquid is increased, on the other hand, pollution is brought, and the green characteristic of the ionic liquid is reduced. The purification steps of the ionic liquid are numerous, and the purification difficulty leads to higher production cost.
Patent CN 111085220A provides a spinel support, active ingredient and adjunct; wherein the auxiliary agent is chloride of transition metal element, and the active component is PdCl 2 According to the preparation method of the catalyst, the spinel carrier and the active components form strong interaction, so that the activity and the selectivity of the catalyst are improved to a certain extent, but the selectivity is still not high to about 90%, HCl is required to be used as a solvent in the preparation process of the catalyst, and roasting is required to be carried out at 150-400 ℃ after the catalyst is impregnated, so that corrosive HCl is volatilized, the performance of the catalyst is evaluated for only 6 hours, the performance of the catalyst is not attenuated and reaches the stable period, and therefore, whether the catalyst can maintain high performance for a long time is doubtful.
Disclosure of Invention
The invention aims to overcome the defects of the prior art and provide a catalyst for synthesizing dimethyl carbonate in a gas phase, which has higher conversion rate and selectivity and longer service life.
The invention is realized by the following technical scheme:
a catalyst for gas phase synthesis of dimethyl carbonate, the catalyst comprising a support and an active component, wherein;
the carrier comprises titanium dioxide, pseudo-boehmite and an auxiliary agent, wherein the mass ratio of the titanium dioxide to the pseudo-boehmite is 1 (1-10), and the auxiliary agent is 0.1% -1% of the sum of the titanium dioxide and the pseudo-boehmite;
the active components comprise soluble palladium salt, perchlorate and zirconium oxychloride, wherein the mass of the soluble palladium salt is 0.1-1% of the mass of the carrier, the molar ratio of the perchlorate to the soluble palladium salt is (1-20): 1, and the mass of the zirconium oxychloride is 0.1-1% of the mass of the carrier;
the auxiliary agent is molybdate.
In the technical scheme, the soluble palladium salt is one or more of palladium chloride, palladium nitrate, palladium acetate and palladium sulfate;
in the technical scheme, the molybdate is one or more of ammonium molybdate, cobalt molybdate, ferric molybdate, manganese molybdate, chromium molybdate, nickel molybdate and tungsten molybdate;
in the above technical scheme, the perchlorate is one or more of copper perchlorate, magnesium perchlorate, cobalt perchlorate, chromium perchlorate, manganese perchlorate and nickel perchlorate.
It is another object of the present invention to provide a method for preparing a catalyst for vapor phase synthesis of dimethyl carbonate.
A method for preparing a catalyst for gas phase synthesis of dimethyl carbonate, comprising the steps of:
step 1, uniformly mixing titanium dioxide, pseudo-boehmite, an auxiliary agent and first deionized water to obtain a first material, granulating the first material to obtain first particles, drying the first particles, and calcining at 300-700 ℃ to obtain a carrier;
in the first material, the mass ratio of the titanium dioxide to the pseudo-boehmite is 1 (1-10), and the mass of the auxiliary agent is 0.1% -1% of the sum of the mass of the titanium dioxide and the pseudo-boehmite; the weight of the first deionized water accounts for 5% -15% of that of the first material;
step 2, dispersing soluble palladium salt, perchlorate and zirconium oxychloride in second deionized water to obtain an impregnating solution;
the mass of the soluble palladium salt is 0.1-1% of the mass of the carrier, the molar ratio of the perchlorate to the soluble palladium salt is (1-20): 1, and the mass of the zirconium oxychloride is 0.1-1% of the mass of the carrier;
the second deionized water amount is the maximum absorption mass of the carrier to deionized water in the step 1;
step 3, dipping the carrier obtained in the step 1 into the dipping liquid obtained in the step 2 for 2-24 hours to obtain a dipped carrier; and drying the impregnated carrier to constant weight to obtain the catalyst for synthesizing the dimethyl carbonate in the gas phase.
In the above technical scheme, the drying temperature of the first particles is 100 ℃.
In the above technical scheme, in the step 1, the process of uniformly mixing the titanium dioxide, the pseudo-boehmite, the auxiliary agent and the first deionized water is completed by adopting a kneader; and granulating the first material by adopting a strip extruder.
In the above technical scheme, in the step 2, the soluble palladium salt, the perchlorate and the zirconium oxychloride are stirred and dispersed in the first deionized water at 20-60 ℃ to obtain the impregnating solution.
In the technical scheme, the soluble palladium salt is one or more of palladium chloride, palladium nitrate, palladium acetate and palladium sulfate;
in the above technical scheme, the molybdate is one or more of ammonium molybdate, cobalt molybdate, ferric molybdate, manganese molybdate, chromium molybdate, nickel molybdate and tungsten molybdate.
In the above technical scheme, the perchlorate is one or more of copper perchlorate, magnesium perchlorate, cobalt perchlorate, chromium perchlorate, manganese perchlorate and nickel perchlorate.
In the technical scheme, in the step 3, the impregnated carrier is dried to constant weight at 60-120 ℃.
In the above technical scheme, the raw material adopted in step 2 may have any water of crystallization, and if the raw material containing water of crystallization is used in step 2, the amount of the solvent is the maximum absorption mass of the carrier to the solvent minus the total mass of the water of crystallization in step 1.
It is another object of the present invention to provide a method for synthesizing dimethyl carbonate.
The synthesis method adopts Methyl Nitrite (MN) and CO as raw materials, and the dimethyl carbonate is obtained through reaction synthesis under the action of the catalyst for gas phase synthesis of the dimethyl carbonate, wherein the catalyst is prepared in the technical scheme;
the synthesis temperature is 110-130 ℃, and the volume airspeed is 2000-2700 h -1 The molar ratio of methyl nitrite to CO is (1-2): 1.
In the technical scheme, the reaction synthesis process is completed in a fixed bed reactor, and the pressure of a catalytic bed layer is 0.2-0.7 MPa.
The invention has the advantages and beneficial effects that:
1. the transition metal element Mo doping effect in the catalytic carrier prepared by the technical proposal of the invention is due to Mo 6+ (r=0.062 nm) and Ti 4+ (r=0.068 nm) has a similar ionic radius so that it can enter TiO 2 Is substituted for Ti 4+ Form new chemical bonds and are located in TiO 2 New energy level is introduced into the forbidden band of the catalyst, so that the activation energy required by DMC reaction is reduced, and the DMC conversion rate can be improved.
2. H is produced during the process of methanol and carbonylation to DMC 2 O，2CH 3 OH+CO+1/2O 2 →(CH 3 O) 2 CO+H 2 O
Zirconium dichloride in the catalyst belongs to a tetragonal crystal structure, is extremely easy to combine with water to generate 8 crystal water to form eight hydrates, thereby accelerating the forward generation of DMC, playing a role in improving DMC conversion rate, and simultaneously Zr in zirconium dichloride molecules 4+ The 4d and 5s orbitals of (2) are all empty, can accept external lone pair electrons, has stronger electronegativity, has the property similar to solid oxide, has synergistic effect with strong oxidizing property of perchlorate, can continuously lead the active center Pd to be 2+ The ion maintains positive 2 valence state, and the service life of the catalyst is prolonged.
3. Perchlorate is a Lewis acid and ClO with strong hygroscopicity 4 － Anions and metal atoms with empty d-orbitals. ClO, compared to other anions 4 － The anion has the strongest electric absorption, the electron cloud density around the metal ion can be reduced, so that the active center Pd ion is beneficial to-ON-OCH in MN molecules 3 Bridging occurs, thereby affecting the-OCH of MN molecules 3 The strength of the bond. In addition, pd atom empty d orbit is occupied by lone electron pair in oxygen atom of MN, so that-OCH in MN molecule 3 The bond strength is changed to make it easier to combine with CO to form-COOCH 3 . Thus, the generation of by-products of dimethoxymethane and methyl formate is avoided, the selectivity is improved, and the mechanism diagram is shown in fig. 13.
4. The catalyst has high CO conversion rate maintained over 30%, DMC selectivity higher than 95%, low reaction temperature, low reaction pressure and long service life.
5. According to the preparation method of the catalyst provided by the invention, hydrochloric acid is not used in the preparation process. Avoiding equipment corrosion caused by volatilization of hydrochloric acid when the catalyst is dried, and almost no waste liquid is discharged due to the maximum water absorption of the carrier when the impregnating solution is prepared. In addition, HCl gas is not needed to be added in the use process of the catalyst so as to ensure the activity and service life of the catalyst, and the corrosion condition of Cl ions to equipment is reduced.
Drawings
FIG. 1 shows a catalyst evaluation apparatus;
FIG. 2 shows a gas chromatograph GC-2014C;
FIG. 3 shows a gas chromatograph GC-2014C with vaporization chamber;
FIGS. 4-7 show SEM pictures of example 1;
FIG. 8 shows the EDS spectrum of example 1;
FIG. 9 shows the IR spectrum of example 1;
FIG. 10 is XPS spectra of the catalyst of example 1 after 500h of evaluation;
FIG. 11 is XPS spectra of comparative example 1c after 500h of catalyst evaluation;
fig. 12 is an XRD spectrum of the catalyst evaluation in example 1: a. example 1 catalyst; b. example 1 after 500 hours of catalyst evaluation;
FIG. 13 is a schematic diagram of the mechanism of vapor phase synthesis of dimethyl carbonate in the present invention.
Other relevant drawings may be made by those of ordinary skill in the art from the above figures without undue burden.
Detailed Description
In order to make the person skilled in the art better understand the solution of the present invention, the following describes the solution of the present invention with reference to specific embodiments.
The materials used in the examples do not contain crystal water
Example 1
A method for preparing a catalyst for synthesizing dimethyl carbonate, comprising the following steps:
step 1: adding titanium dioxide, pseudo-boehmite, ammonium molybdate and deionized water 1 into a kneader for kneading to obtain a first material after the kneading is finished, pouring the first material into a strip extruder for strip extrusion, drying the extruded strip at 100 ℃, and calcining at 300 ℃ to obtain a carrier, wherein the mass ratio of the titanium dioxide to the pseudo-boehmite is 1:1, the addition amount of the ammonium molybdate is 0.1 percent of the sum of the masses of the titanium dioxide and the pseudo-boehmite, and the addition amount of the deionized water 1 is 5 percent of the total mass of the first material.
Step 2: stirring and dispersing palladium chloride, copper perchlorate and zirconium oxychloride in deionized water 2 at 20 ℃ to obtain an impregnating solution, wherein the adding amount of the palladium chloride is 0.1% of the mass of the carrier, the molar ratio of the adding amount of the copper perchlorate to the palladium chloride is 20:1, the adding amount of the zirconium oxychloride is 1% of the carrier, and determining the using amount of the deionized water 2 by adopting an equal volume impregnation method;
step 3: and (3) dipping the carrier in the step (1) into the dipping liquid in the step (2), wherein the dipping process lasts for 2 hours, and after the dipping is finished, putting the material into a baking oven, and drying at 60 ℃ to constant weight to obtain the catalyst.
Comparative example 1
Comparative example 1 was different from example 1 only in that no molybdate auxiliary was added in step 1 of comparative example 1, and the other raw material ratios and reaction parameters were the same as those of example 1, to prepare a No. 1a catalyst.
Comparative example 2
Comparative example 2 was different from example 1 only in that no perchlorate-type auxiliary agent was added in comparative example 2, and the other raw material ratios and reaction parameters were the same as in example 1, to prepare a No. 1b catalyst.
Comparative example 3
Comparative example 3 was different from example 1 only in that zirconium oxychloride was not added in comparative example 3, and other raw material ratios and reaction parameters were the same as in example 1, to prepare a catalyst No. 1 c.
Example 2
A method for preparing a catalyst for synthesizing dimethyl carbonate, comprising the following steps:
step 1: adding titanium dioxide, pseudo-boehmite, ammonium molybdate and deionized water 1 into a kneader for kneading to obtain a first material after the kneading is finished, pouring the first material into a strip extruder for strip extrusion, drying the extruded strip at 100 ℃, and calcining at 500 ℃ to obtain a carrier, wherein the mass ratio of the titanium dioxide to the pseudo-boehmite is 1:5, the addition amount of the ammonium molybdate is 0.5 percent of the sum of the masses of the titanium dioxide and the pseudo-boehmite, and the addition amount of the deionized water 1 is 10 percent of the total mass of the first material.
Step 2: stirring and dispersing palladium chloride, copper perchlorate and zirconium oxychloride in deionized water 2 at 40 ℃ to obtain an impregnating solution, wherein the adding amount of the palladium chloride is 0.5% of the mass of the carrier, the molar ratio of the adding amount of the copper perchlorate to the palladium chloride is 10:1, the adding amount of the zirconium oxychloride is 0.5% of the carrier, and determining the using amount of the deionized water 2 by adopting an equal volume impregnation method;
step 3: and (3) dipping the carrier in the step (1) into the dipping liquid in the step (2), wherein the dipping process lasts for 12 hours, and after the dipping is finished, putting the material into a baking oven, and drying at 90 ℃ to constant weight to obtain the catalyst.
Example 3
A method for preparing a catalyst for synthesizing dimethyl carbonate, comprising the following steps:
step 1: adding titanium dioxide, pseudo-boehmite, cobalt molybdate and deionized water 1 into a kneader for kneading to obtain a first material after the kneading is finished, pouring the first material into a strip extruder for strip extrusion, drying the extruded strip at 100 ℃, and calcining at 700 ℃ to obtain a carrier, wherein the mass ratio of the titanium dioxide to the pseudo-boehmite is 1:10, the addition amount of the cobalt molybdate is 1% of the sum of the masses of the titanium dioxide and the pseudo-boehmite, and the addition amount of the deionized water 1 is 15% of the total mass of the first material.
Step 2: stirring and dispersing palladium acetate, magnesium perchlorate and zirconium oxychloride in deionized water 2 at 60 ℃ to obtain an impregnating solution, wherein the adding amount of the palladium acetate is 1% of the mass of the carrier, the molar ratio of the adding amount of the magnesium perchlorate to the palladium acetate is 1:1, the adding amount of the zirconium oxychloride is 0.1% of the carrier, and determining the using amount of the deionized water 2 by adopting an equal volume impregnation method;
step 3: and (3) dipping the carrier in the step (1) into the dipping liquid in the step (2), wherein the dipping process lasts for 24 hours, and after the dipping is finished, putting the material into a baking oven, and drying at 120 ℃ to constant weight to obtain the catalyst.
Example 4
A method for preparing a catalyst for synthesizing dimethyl carbonate, comprising the following steps:
step 1: adding titanium dioxide, pseudo-boehmite, ferric molybdate and deionized water 1 into a kneader for kneading, obtaining a first material after the kneading is finished, pouring the first material into a strip extruder for strip extrusion, drying the extruded strip at 100 ℃, and calcining at 300 ℃ to obtain a carrier, wherein the mass ratio of the titanium dioxide to the pseudo-boehmite is 1:1, the addition amount of the ferric molybdate is 0.1 percent of the sum of the masses of the titanium dioxide and the pseudo-boehmite, and the addition amount of the deionized water 1 is 5 percent of the total mass of the first material.
Step 2: stirring and dispersing palladium nitrate, cobalt perchlorate and zirconium oxychloride in deionized water 2 at 20 ℃ to obtain an impregnating solution, wherein the adding amount of the palladium nitrate is 0.1% of the mass of the carrier, the molar ratio of the adding amount of the cobalt perchlorate to the palladium nitrate is 10:1, the adding amount of the zirconium oxychloride is 0.5% of the carrier, and determining the using amount of the deionized water 2 by adopting an equal volume impregnation method;
step 3: and (3) dipping the carrier in the step (1) into the dipping liquid in the step (2), wherein the dipping process lasts for 2 hours, and after the dipping is finished, putting the material into a baking oven, and drying at 60 ℃ to constant weight to obtain the catalyst.
Example 5
A method for preparing a catalyst for synthesizing dimethyl carbonate, comprising the following steps:
step 1: adding titanium dioxide, pseudo-boehmite, manganese molybdate and deionized water 1 into a kneader for kneading to obtain a first material after the kneading is finished, pouring the first material into a strip extruder for strip extrusion, drying the extruded strip at 100 ℃, and calcining at 500 ℃ to obtain a carrier, wherein the mass ratio of the titanium dioxide to the pseudo-boehmite is 1:1, the addition amount of the manganese molybdate is 0.1 percent of the sum of the masses of the titanium dioxide and the pseudo-boehmite, and the addition amount of the deionized water 1 is 10 percent of the total mass of the first material.
Step 2: stirring and dispersing palladium sulfate, chromium perchlorate and zirconium oxychloride in deionized water 2 at 40 ℃ to obtain an impregnating solution, wherein the adding amount of the palladium sulfate is 0.5% of the mass of the carrier, the molar ratio of the adding amount of the chromium perchlorate to the adding amount of the palladium chloride is 1:1 respectively, the adding amount of the zirconium oxychloride is 0.1% of the carrier, and determining the using amount of the deionized water 2 by adopting an equal volume impregnation method;
step 3: and (3) dipping the carrier in the step (1) into the dipping liquid in the step (2), wherein the dipping process lasts for 12 hours, and after the dipping is finished, putting the material into a baking oven, and drying at 90 ℃ to constant weight to obtain the catalyst.
Example 6
A method for preparing a catalyst for synthesizing dimethyl carbonate, comprising the following steps:
step 1: adding titanium dioxide, pseudo-boehmite, chromium molybdate and deionized water 1 into a kneader for kneading to obtain a first material after the kneading is finished, pouring the first material into a strip extruder for strip extrusion, drying the extruded strip at 100 ℃, and calcining at 700 ℃ to obtain a carrier, wherein the mass ratio of the titanium dioxide to the pseudo-boehmite is 1:1, the adding amount of the chromium molybdate is 0.1 percent of the sum of the masses of the titanium dioxide and the pseudo-boehmite, and the adding amount of the deionized water 1 is 15 percent of the total mass of the first material.
Step 2: stirring and dispersing palladium chloride, manganese perchlorate and zirconium oxychloride in deionized water 2 at 60 ℃ to obtain an impregnating solution, wherein the adding amount of the palladium chloride is 1% of the mass of the carrier, the molar ratio of the adding amount of the manganese perchlorate to the palladium chloride is 20:1, the adding amount of the zirconium oxychloride is 1% of the carrier, and determining the using amount of the deionized water 2 by adopting an equal volume impregnation method;
step 3: and (3) dipping the carrier in the step (1) into the dipping liquid in the step (2), wherein the dipping process lasts for 12 hours, and after the dipping is finished, putting the material into a baking oven, and drying at 90 ℃ to constant weight to obtain the catalyst.
Example 7
A method for preparing a catalyst for synthesizing dimethyl carbonate, comprising the following steps:
step 1: adding titanium dioxide, pseudo-boehmite, tungsten molybdate and deionized water 1 into a kneader for kneading to obtain a first material after the kneading is finished, pouring the first material into a strip extruder for strip extrusion, drying the extruded strip at 100 ℃, and calcining at 300 ℃ to obtain a carrier, wherein the mass ratio of the titanium dioxide to the pseudo-boehmite is 1:1, the adding amount of the tungsten molybdate is 0.1 percent of the sum of the masses of the titanium dioxide and the pseudo-boehmite, and the adding amount of the deionized water 1 is 5 percent of the total mass of the first material.
Step 2: stirring and dispersing palladium acetate, nickel perchlorate and zirconium oxychloride in deionized water 2 at 20 ℃ to obtain an impregnating solution, wherein the adding amount of the palladium chloride is 0.1% of the mass of the carrier, the molar ratio of the adding amount of the nickel perchlorate to the palladium acetate is 10:1, the adding amount of the zirconium oxychloride is 0.5% of the carrier, and determining the using amount of the deionized water 2 by adopting an equal volume impregnation method;
step 3: and (3) dipping the carrier in the step (1) into the dipping liquid in the step (2), wherein the dipping process lasts for 24 hours, and after the dipping is finished, putting the material into a baking oven, and drying at 120 ℃ to constant weight to obtain the catalyst.
Example 8
A method for preparing a catalyst for synthesizing dimethyl carbonate, comprising the following steps:
step 1: adding titanium dioxide, pseudo-boehmite, nickel molybdate and deionized water 1 into a kneader for kneading to obtain a first material after the kneading is finished, pouring the first material into a strip extruder for strip extrusion, drying the extruded strip at 100 ℃, and calcining at 500 ℃ to obtain a carrier, wherein the mass ratio of the titanium dioxide to the pseudo-boehmite is 1:1, the adding amount of the nickel molybdate is 0.1 percent of the sum of the masses of the titanium dioxide and the pseudo-boehmite, and the adding amount of the deionized water 1 is 15 percent of the total mass of the first material.
Step 2: stirring and dispersing palladium sulfate, cobalt perchlorate and zirconium oxychloride in deionized water 2 at 40 ℃ to obtain an impregnating solution, wherein the adding amount of the palladium chloride is 0.5% of the mass of the carrier, the molar ratio of the adding amount of the cobalt perchlorate to the palladium sulfate is 1:1, the adding amount of the zirconium oxychloride is 0.1% of the carrier, and determining the using amount of the deionized water 2 by adopting an equal volume impregnation method;
step 3: and (3) dipping the carrier in the step (1) into the dipping liquid in the step (2), wherein the dipping process lasts for 2 hours, and after the dipping is finished, putting the material into a baking oven, and drying at 60 ℃ to constant weight to obtain the catalyst.
Example 9
A method for preparing a catalyst for synthesizing dimethyl carbonate, comprising the following steps:
step 1: adding titanium dioxide, pseudo-boehmite, ferric molybdate and deionized water 1 into a kneader for kneading, obtaining a first material after the kneading is finished, pouring the first material into a strip extruder for strip extrusion, drying the extruded strip at 100 ℃, and calcining at 700 ℃ to obtain a carrier, wherein the mass ratio of the titanium dioxide to the pseudo-boehmite is 1:1, the addition amount of the ferric molybdate is 0.1 percent of the sum of the masses of the titanium dioxide and the pseudo-boehmite, and the addition amount of the deionized water 1 is 10 percent of the total mass of the first material.
Step 2: stirring and dispersing palladium nitrate, cobalt perchlorate and zirconium oxychloride in deionized water 2 at 60 ℃ to obtain an impregnating solution, wherein the adding amount of the palladium chloride is 1% of the mass of the carrier, the molar ratio of the adding amount of the cobalt perchlorate to the adding amount of the palladium chloride is 20:1 respectively, the adding amount of the zirconium oxychloride is 1% of the carrier, and determining the using amount of the deionized water 2 by adopting an equal volume impregnation method;
step 3: and (3) dipping the carrier in the step (1) into the dipping liquid in the step (2), wherein the dipping process lasts for 12 hours, and after the dipping is finished, putting the material into a baking oven, and drying at 90 ℃ to constant weight to obtain the catalyst.
Example 10
This example is a performance evaluation of the liquid-phase chlorine-free catalysts No. 1 to 9 prepared in examples 1 to 9 and the catalysts No. 1a, 1b and 1c prepared in comparative examples 1 to 3.
The synthesis reaction of the experimental case adopts a low-pressure fixed bed reactor, and adopts a gas phase method for CO coupling and regeneration. The prior process flow for synthesizing and preparing the dimethyl carbonate comprises the following specific steps:
(1) NO, O 2 Introducing anhydrous methanol into a packed tower respectively for reaction to obtain a component CH 3 ONO, NO and N 2 Wherein the reaction pressure is 0.6MPa, the reaction temperature is 20 ℃ and the space velocity is 2800h -1 ；NO。O 2 And anhydrous methanol in a molar ratio of 5.9:1:5, nitrogen being the balance gas, the volumes of which are CO and O 2 1.5 times the total volume. Wherein NO is in sufficient quantity and anhydrous methanol is in excess. The height of the packed tower is 1500mm, the diameter is 120+/-5 mm, the flow rate of the liquid phase is 50ml/min, the liquid phase is fed from the upper section of the packed tower and circulates from top to bottom, the gas phase is fed from the lower section of the packed tower, and the product is discharged from the middle part;
(2) Mixing the first mixed gas and CO, introducing the mixed gas and CO into a fixed bed reactor as raw material gas, and controlling the catalyst bed pressure to be 0.5Mpa, the reaction bed temperature to be 125 ℃ and the volume space velocity to be 3500h -1 The retention time is 1.5s, and finally the dimethyl carbonate product is obtained, wherein the intake gas comprises the following components in percentage by volume: CO 11.12%, N 2 57.68％、NO 11.56％、CH 3 ONO 19.64%, the fixed bed reactor is a tubular reactor loaded with catalyst, the internal diameter is 50mm, the length is 500mm, and the catalyst loading is 10ml.
(3) Gas phase component analysis
(4) The gas phase component analysis adopts an Shimadzu GC-2014C gas chromatograph for on-line analysis.
(5) Analysis of liquid phase Components
(6) Liquid phase product analysis of the reaction was also performed using Shimadzu GC-2014C with vaporization chamber.
(7) Coupling CO gas phase to CH 3 Calculation of catalyst performance evaluation for ONO synthesis of DMC shows:
(8) CO conversion (x) =converted CO (mol)/CO (mol) of feed x 100%
(9) DMC Selectivity(s) =amount of product DMC (mol)/amount of total product (mol). Times.100%
(10) Mass space time yield of DMC (sty) =weight of product DMC (g) ×product DMC content%/[ catalyst volume (L) ×time (h) ]×100%
(11) The evaluation time of the implementation cases is 500h
The results of the performance evaluation are shown in the following table:
according to the results of Table 1, the initial CO conversion was 25.21% -37.66% when DMC was synthesized using the methanol gas phase catalysts No. 1-9 prepared in examples 1-9; DMC selectivity is 89.34% -97.24%; DMC space-time yield is 564.87-843.83g (g/Lcat.h), and CO conversion rate is 20.92% -35.93% after 500 h; DMC selectivity was 83.39% -95.15%; DMC space-time yields ranged from 468.75 to 805.07g (g/Lcat.h).
The TiO of the present patent is known from example 1 and comparative example 1a 2 The transition metal element Mo is used as a carrier and the doping effect of the Mo is due to the fact that 6+ (r=0.062 nm) and Ti 4+ (r=0.068 nm) has a similar ionic radius so that it can enter TiO 2 Is substituted for Ti 4+ Form new chemical bonds and are located in TiO 2 New energy level is introduced into the forbidden band of the catalyst, so that the activation energy required by DMC reaction is reduced, and the DMC conversion rate is improved. FIGS. 4 to 7 are SEM pictures of the catalyst of example 1 after 500h evaluation, the catalyst has relatively uniform voids and complete crystal lattice from the pictures, showing good impregnation effect, FIG. 8 is EDS spectrum of catalyst section, mo is found in Ti lattice structure from EDS data, FIG. 9 is infrared spectrum, and 650cm is found from the graph -1 A stronger Ti-O stretching vibration peak is arranged at the position of 1600-1700cm -1 The Ti-O-Mo has a stronger stretching vibration peak, which indicates that Mo has been doped into TiO 2 The lattice forms new chemical bonds, validating the previous theory.
Compared with the catalyst of example 1, the catalyst of the No. 1b catalyst does not add perchlorate, the catalyst loses the characteristic of perchlorate Lewis acid, and ClO with strong electric absorbency does not exist 4 － Anions and metal atoms with empty d-orbitals, leading to the formation of CO bonds to-COOCH 3 The trend becomes weaker. The production of by-product dimethoxy methane and methyl formate is increased, the CO conversion rate and DMC selectivity are obviously lower, the catalyst is unstable, and the catalyst performance is greatly reduced after 500 hours.
As can be seen from a comparison of the catalysis of example 1 and comparative example 1c, the CO conversion and DMC selectivity are much higher after the zirconium oxychloride is added in the examples. The reason is that the oxidation generated by the synergistic action of zirconium oxychloride and perchlorate can continuously lead to the active center Pd 2+ The ion maintains positive 2 valence state, which makes the catalyst service life longer.
FIGS. 10 and 11 are XPS spectra of the catalyst of example 1 and the catalyst of comparative example 1c, respectively, after 500h evaluation, it can be seen from FIG. 10 that the catalyst of example 1 has a higher strength Pd at 342ev after 500h 2+ Peak at 338ev with higher intensity Pd 4+ Pd at 335ev 0 The peak was very weak and FIG. 11, comparative example 1c, was a Pd having a relatively high intensity at 342ev 2+ Peak, pd at 335ev 0 The peaks are also very strong, which indicates that the Pd of comparative example 1C has been reduced to the 0-valence state for the most part, which is also the main reason for the low selectivity of the conversion of the comparative example, while the reduction of the active center Pd to the 0-valence state for the most part indicates a lower lifetime.
The XRD spectra before and after 500h of the catalyst of example 1 are shown in fig. 12, and it can be seen from the spectra that the XRD characteristic peak position before and after the evaluation is not changed, but the peak intensity is reduced to some extent, which indicates that the evaluation process has an influence on the crystallinity of the catalyst, but the influence is not great, that is, the service life of the catalyst is long.
Relational terms such as "first" and "second", and the like may be used solely to distinguish one element from another element having the same name, without necessarily requiring or implying any actual such relationship or order between such elements.
The foregoing has described exemplary embodiments of the invention, it being understood that any simple variations, modifications, or other equivalent arrangements which would not unduly obscure the invention may be made by those skilled in the art without departing from the spirit of the invention.
Claims (10)
1. A catalyst for gas phase synthesis of dimethyl carbonate, characterized in that the catalyst comprises a carrier and an active component, wherein;
the carrier comprises titanium dioxide, pseudo-boehmite and an auxiliary agent, wherein the mass ratio of the titanium dioxide to the pseudo-boehmite is 1 (1-10), and the auxiliary agent is 0.1% -1% of the sum of the titanium dioxide and the pseudo-boehmite;
the active components comprise soluble palladium salt, perchlorate and zirconium oxychloride, wherein the mass of the soluble palladium salt is 0.1-1% of the mass of the carrier, the molar ratio of the perchlorate to the soluble palladium salt is (1-20): 1, and the mass of the zirconium oxychloride is 0.1-1% of the mass of the carrier;
the auxiliary agent is molybdate;
the molybdate is one or more of ammonium molybdate, cobalt molybdate, iron molybdate, manganese molybdate, chromium molybdate, nickel molybdate and tungsten molybdate; the perchlorate is one or more of copper perchlorate, magnesium perchlorate, cobalt perchlorate, chromium perchlorate, manganese perchlorate and nickel perchlorate.
2. The catalyst of claim 1, wherein the soluble palladium salt is one or more of palladium chloride, palladium nitrate, palladium acetate, palladium sulfate.
3. A process for preparing a catalyst for the vapor phase synthesis of dimethyl carbonate, comprising the steps of:
step 1, uniformly mixing titanium dioxide, pseudo-boehmite, an auxiliary agent and first deionized water to obtain a first material, granulating the first material to obtain first particles, drying the first particles, and calcining at 300-700 ℃ to obtain a carrier;
in the first material, the mass ratio of the titanium dioxide to the pseudo-boehmite is 1 (1-10), and the mass of the auxiliary agent is 0.1% -1% of the sum of the mass of the titanium dioxide and the pseudo-boehmite; the weight of the first deionized water accounts for 5% -15% of that of the first material;
the auxiliary agent is molybdate;
step 2, dispersing soluble palladium salt, perchlorate and zirconium oxychloride in second deionized water to obtain an impregnating solution;
the mass of the soluble palladium salt is 0.1-1% of the mass of the carrier, the molar ratio of the perchlorate to the soluble palladium salt is (1-20): 1, and the mass of the zirconium oxychloride is 0.1-1% of the mass of the carrier;
the second deionized water amount is the maximum absorption mass of the carrier to deionized water in the step 1;
step 3, dipping the carrier obtained in the step 1 into the dipping liquid obtained in the step 2 for 2-24 hours to obtain a dipped carrier; drying the impregnated carrier to constant weight to obtain the catalyst for synthesizing the dimethyl carbonate in the gas phase;
the molybdate is one or more of ammonium molybdate, cobalt molybdate, iron molybdate, manganese molybdate, chromium molybdate, nickel molybdate and tungsten molybdate; the perchlorate is one or more of copper perchlorate, magnesium perchlorate, cobalt perchlorate, chromium perchlorate, manganese perchlorate and nickel perchlorate.
4. A method of preparing as claimed in claim 3, wherein the first particles are dried at a temperature of 100 ℃.
5. The method according to claim 3, wherein the step 1 of uniformly mixing the titanium dioxide, the pseudo-boehmite, the auxiliary agent and the first deionized water is performed by using a kneader; and granulating the first material by adopting a strip extruder.
6. The method according to claim 3, wherein in step 2, the soluble palladium salt, perchlorate and zirconium oxychloride are dispersed in the first deionized water at 20 to 60 ℃ with stirring to obtain the impregnating solution.
7. The method according to claim 3, wherein the soluble palladium salt is one or more of palladium chloride, palladium nitrate, palladium acetate and palladium sulfate.
8. A method according to claim 3, wherein in step 3, the impregnated support is dried to constant weight at 60-120 ℃.
9. A method for synthesizing dimethyl carbonate, which is characterized in that methyl nitrite and CO are adopted as raw materials in the synthesis method, and dimethyl carbonate is obtained through reaction synthesis under the action of the catalyst for gas phase synthesis of dimethyl carbonate obtained by the preparation method according to any one of claims 3 to 8;
the synthesis temperature is 110-130 ℃, and the volume airspeed is 2000-2700 h -1 The molar ratio of methyl nitrite to CO is (1-2): 1.
10. The method for synthesizing dimethyl carbonate according to claim 9, wherein the reaction synthesis process is completed in a fixed bed reactor, and the pressure of the catalytic bed layer is 0.2-0.7 MPa.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202111653371.6A CN114289040B (en) | 2021-12-30 | 2021-12-30 | Catalyst for gas phase synthesis of dimethyl carbonate and preparation method thereof |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202111653371.6A CN114289040B (en) | 2021-12-30 | 2021-12-30 | Catalyst for gas phase synthesis of dimethyl carbonate and preparation method thereof |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN114289040A CN114289040A (en) | 2022-04-08 |
| CN114289040B true CN114289040B (en) | 2023-09-19 |
Family
ID=80973432
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202111653371.6A Active CN114289040B (en) | 2021-12-30 | 2021-12-30 | Catalyst for gas phase synthesis of dimethyl carbonate and preparation method thereof |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN114289040B (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114939413A (en) * | 2022-06-20 | 2022-08-26 | 陕西延长石油（集团）有限责任公司 | Catalyst for catalyzing methanol to directly synthesize dimethyl carbonate and preparation method and application thereof |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1380140A (en) * | 2001-04-16 | 2002-11-20 | 中国科学院山西煤炭化学研究所 | Catalyst for synthesizing dimethyl carbonate and its application |
| CN101003018A (en) * | 2006-01-20 | 2007-07-25 | 中国石油天然气股份有限公司 | Heterogeneous catalysis solid base catalyst and preparation method and application thereof |
| KR20140040539A (en) * | 2012-09-26 | 2014-04-03 | 한국화학연구원 | Preparation method for dimethyl carbonate by using greenhouse gases |
| CN111111670A (en) * | 2019-12-05 | 2020-05-08 | 华茂伟业绿色科技股份有限公司 | Supported catalyst and preparation method and application thereof |
-
2021
- 2021-12-30 CN CN202111653371.6A patent/CN114289040B/en active Active
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1380140A (en) * | 2001-04-16 | 2002-11-20 | 中国科学院山西煤炭化学研究所 | Catalyst for synthesizing dimethyl carbonate and its application |
| CN101003018A (en) * | 2006-01-20 | 2007-07-25 | 中国石油天然气股份有限公司 | Heterogeneous catalysis solid base catalyst and preparation method and application thereof |
| KR20140040539A (en) * | 2012-09-26 | 2014-04-03 | 한국화학연구원 | Preparation method for dimethyl carbonate by using greenhouse gases |
| CN111111670A (en) * | 2019-12-05 | 2020-05-08 | 华茂伟业绿色科技股份有限公司 | Supported catalyst and preparation method and application thereof |
Non-Patent Citations (4)
| Title |
|---|
| Amorphous magnesium substituted mesoporous aluminophosphate: An acid-base sites synergistic catalysis for transesterification of diethyl carbonate and dimethyl carbonate in fixed-bed reactor;Wang HF等;MICROPOROUS AND MESOPOROUS MATERIALS;第292卷;109757 * |
| CeO2–ZrO2 solid solution catalyst for selective synthesis of dimethyl carbonate from methanol and carbon dioxide;Tomishige K等;Catalysis Letters;第76卷;71-74 * |
| Effective and green synthesis of methyl pyrrole-1-carboxylate with dimethyl carbonate over solid base;Fan S等;Catalysis letters;第120卷;299-302 * |
| Reactivity of heteropolytungstate and heteropolymolybdate metal transition salts in the synthesis of dimethyl carbonate from methanol and CO2;Aouissi A等;International Journal of Molecular Sciences;第11卷(第7期);2770-2779 * |
Also Published As
| Publication number | Publication date |
|---|---|
| CN114289040A (en) | 2022-04-08 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| EP3263213B1 (en) | Catalyst for manufacturing unsaturated aldehyde and/or unsaturated carboxylic acid and manufacturing method of same, and manufacturing method of unsaturated aldehyde and/or unsaturated carboxylic acid | |
| EP2807137B1 (en) | Process for producing fluorine-containing olefin | |
| CN1054972A (en) | Method for producing propenoic acid | |
| CN114289040B (en) | Catalyst for gas phase synthesis of dimethyl carbonate and preparation method thereof | |
| CN1241164A (en) | Method of hydrocarbon reforming and catalyst and catalyst precursor therefor | |
| KR101270678B1 (en) | Copper-based catalyst for the conversion of ethanol to acetaldehyde by dehydrogenation and preparing method of the same | |
| CN109641192A (en) | The manufacturing method of methacrylic acid catalyst for producing and its manufacturing method and methacrylic acid and methacrylate | |
| CN1859972A (en) | Catalyst for gaseous partial oxidation of propylene and its preparing method | |
| CN114210342B (en) | Catalyst for synthesizing dimethyl carbonate from methanol in gas phase, preparation method and dimethyl carbonate synthesizing method | |
| CN111659377B (en) | Carbonylation catalyst for synthesizing dimethyl carbonate with high selectivity and preparation and application thereof | |
| KR101921112B1 (en) | Supported transition metal selenide catalyst, process for producing same, and process for producing urethane using same | |
| CN117299111A (en) | Ternary H x V 2 O 5 /LaVO 4 /WO 3 Catalyst, preparation method and application thereof | |
| KR101199999B1 (en) | Supported Copper Catalysts for Synthesis of Dimethyl Carbonate by Oxidative Carbonylation of Methanol | |
| CN113398912B (en) | Catalyst for synthesizing dimethyl carbonate by alcoholysis of methyl carbamate | |
| KR20140129935A (en) | Method for preparing dimethyl carbonate using supported catalyst | |
| JPH1099694A (en) | Photocatalyst and its preparation | |
| CN111992248B (en) | Catalyst for oxidation esterification of isobutene, preparation method and application thereof | |
| CN112044440B (en) | Catalyst for preparing chlorine gas by catalytic oxidation of hydrogen chloride and preparation method and application thereof | |
| CN114029058A (en) | Catalyst for preparing 1,3-dihydroxyacetone by glycerol oxidation and method thereof | |
| CN112156795A (en) | Catalyst and preparation method and application thereof | |
| CN104801291B (en) | Zn/ gold/mesoporous carbon catalysts for producing chloroethanes and preparation method thereof | |
| KR20170116745A (en) | Preparation method of acrylic acid | |
| JP7161664B2 (en) | Method for producing catalyst for hydrogen production | |
| JPH10165820A (en) | Photocatalyst, its production and production of hydrogen using the catalyst | |
| JP4284740B2 (en) | Method for preparing palladium-antimony alloy catalyst |
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 | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |