CN115364888B - Supported hydrodechlorination catalyst, preparation method and application thereof, and method for preparing chlorotrifluoroethylene by using catalyst - Google Patents
Supported hydrodechlorination catalyst, preparation method and application thereof, and method for preparing chlorotrifluoroethylene by using catalyst Download PDFInfo
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Abstract
The invention belongs to the technical field of chemical catalysis, and provides a supported hydrodechlorination catalyst, a preparation method and application thereof, and a method for preparing chlorotrifluoroethylene by using the catalyst, aiming at the defect of overhigh production cost of the conventional common hydrodechlorination catalyst. The supported hydrodechlorination catalyst comprises ruthenium and copper as main catalysts, molybdenum nitride as an auxiliary agent and active carbon as a carrier. The preparation method of the catalyst comprises carrier pretreatment; preparing a catalyst intermediate and a precursor; and (4) roasting. The supported hydrodechlorination catalyst is adopted for preparing the chlorotrifluoroethylene. The catalyst can greatly reduce the industrial production cost of hydrodechlorination, has the hydrodechlorination catalytic effect which is equivalent to noble metal palladium, and is favorable for the hydrodechlorination catalyst to be better suitable for large-scale industrial production, such as the preparation of chlorotrifluoroethylene by a catalytic hydrodechlorination method.
Description
Technical Field
The invention belongs to the technical field of chemical catalysis, and particularly relates to a supported hydrodechlorination catalyst, a preparation method and application thereof, and a method for preparing chlorotrifluoroethylene by using the catalyst.
Background
Chlorotrifluoroethylene (CTFE) is an important fluorine-containing monomer, and can be used for preparing a series of chemical products such as fluorine-containing coatings, fluorine-containing resins, fluorine-containing rubbers, chlorofluorocarbon lubricating oil and the like. The chemical products have excellent physical and chemical properties, and can be widely applied to the building industry, the military aerospace field and the electronic technology.
The current methods for preparing chlorotrifluoroethylene are: a trifluoro trichloroethane metal zinc powder reduction dechlorination method; catalytic hydrogenation dechlorination of trifluorotrichloroethane; a catalytic dechlorination method of trifluorotrichloroethane under the participation of ethylene and oxygen, and the like. The catalytic hydrogenation and dechlorination method of the trifluorotrichloroethane can effectively avoid the use of inflammable, toxic methanol and explosive zinc powder, does not generate byproducts such as zinc chloride which cause harm to the environment, has green and environment-friendly preparation process and higher industrial value, and is widely applied.
Catalytic hydrogenation dechlorination method of trifluorotrichloroethane by using trifluorotrichloroethane (molecular formula is C) 2 Cl 3 F 3 ) And hydrogen as raw material, under the catalytic action of hydrodechlorination catalyst, the trifluorotrichloroethane selectively makes a series of reactions to remove chlorine atom, at the same time, the hydrogen atom is introduced so as to obtain the target product chlorotrifluoroethylene (molecular formula is C) with high added value 2 ClF 3 ) The specific reaction formula is as follows:
from the above reaction formulae, it is known that trifluorotrichloroethane is hydrodechlorinated in the presence of a catalyst, and that trifluoroethylene, trifluorochloroethane and trifluorodichloroethane are by-produced as well as the desired chlorotrifluoroethylene. The yield of the desired product chlorotrifluoroethylene is therefore strongly dependent on the hydrodechlorination catalyst, in particular the selectivity of the catalyst.
The hydrodechlorination catalyst mainly used at present is a noble metal catalyst. The noble metal is widely applied to the hydrodechlorination reaction due to the mild reaction condition and excellent performance.
CN112657527A discloses a non-alloy catalyst and its preparation method, the catalyst comprises a carrier and an active component, the carrier is nitrogen-doped carbon material, the active component comprises palladium and copper.
CN1460549A discloses a catalyst for preparing chlorotrifluoroethylene by catalytic hydrodechlorination of trifluorotrichloroethane and a preparation method thereof, wherein the catalyst comprises a carrier and an active component, the carrier is activated carbon, the active component comprises noble metal palladium and metal copper, and alkali metal lithium and rare earth metal (or metal lanthanum) are added as auxiliary agents.
CN105457651A discloses a hydrodechlorination catalyst and application thereof in preparation of chlorotrifluoroethylene, wherein the main catalyst is Pd and Cu; the auxiliary agent is selected from one, two or more than three of Mg, ca, ba, co, mo, ni, sm and Ce.
The main catalysts in the hydrodechlorination catalysts in the patents contain noble metal palladium, and although current researches show that the hydrodechlorination catalytic effect of the noble metal palladium is good, the noble metal palladium is 597-602 yuan/g, which is expensive, and the industrial cost is undoubtedly too high if the catalyst is used for large-scale industrial production. If expensive noble metal palladium in the existing hydrodechlorination catalyst can be replaced, considerable economic benefit can be brought.
CN1351903A discloses a catalyst for preparing trifluorochloroethylene and trifluoroethylene by catalytic hydrodechlorination, noble metal ruthenium and metal copper are used as main active components, lanthanum-rich mischmetal and alkali metal lithium are added as modifying auxiliaries, and coconut shell activated carbon is used as a carrier. The hydrodechlorination catalyst in the patent replaces palladium with ruthenium, and adds an auxiliary agent, namely lanthanum-rich mischmetal and alkali metal lithium, so that the service life of the catalyst is prolonged by inhibiting carbon deposition through the auxiliary agent. Although the catalyst adopts noble metal ruthenium to completely replace noble metal palladium, when the catalyst is used for preparing chlorotrifluoroethylene by catalytic hydrogenation and dechlorination, the selectivity of the chlorotrifluoroethylene only reaches about 80 percent and is far lower than the catalytic effect of the palladium-containing catalyst under the same reaction condition.
Therefore, a hydrodechlorination catalyst is urgently needed, which can solve the problem of overhigh cost of the existing hydrodechlorination catalyst, and can completely reach the catalytic level of noble metal palladium in the aspect of catalytic effect so as to be better suitable for large-scale industrial production.
Disclosure of Invention
The invention aims to provide a supported hydrodechlorination catalyst aiming at the defects that the existing common hydrodechlorination catalysts contain noble metal palladium, although the catalytic effect is better, the production cost is overhigh, the catalyst can greatly reduce the industrial production cost of hydrodechlorination, has the hydrodechlorination catalytic effect which is equivalent to that of the noble metal palladium, and is beneficial to the hydrodechlorination catalyst to be better suitable for large-scale industrial production, such as the preparation of chlorotrifluoroethylene by a catalytic hydrodechlorination method.
In order to reduce the industrial production cost, the inventor selects cheap noble metal ruthenium to replace expensive noble metal palladium, introduces metal copper to assist the noble metal ruthenium, and designs ruthenium and copper as main catalysts. Considering that most of the noble metal belts have toxicity and cause environmental pollution if the noble metal belts are not properly treated after use, the inventor designs the catalyst into a supported catalyst, and a main catalyst is supported on carrier active carbon, so that the use amount of the noble metal is reduced to the maximum extent, and meanwhile, the production cost can be further reduced due to the small use amount of the noble metal. Based on ruthenium and copper as main catalysts, the inventor finds that the molybdenum nitride is introduced into the catalyst as an auxiliary agent, so that the catalytic activity and selectivity of the catalyst can be improved, and the catalytic effect of the catalyst can reach the level of the existing hydrodechlorination catalyst containing noble metal palladium, and is even better.
The specific technical scheme is as follows:
a supported hydrodechlorination catalyst comprises ruthenium and copper as main catalysts, molybdenum nitride as an auxiliary agent and active carbon as a carrier.
Further, the ruthenium content in the supported hydrodechlorination catalyst is 0.05-4.0% of the total weight of the catalyst, the copper content is 0.2-6.0% of the total weight of the catalyst, and the molybdenum nitride content is 0.5-5.0% of the total weight of the catalyst; the balance being carrier active carbon.
The noble metal ruthenium and the metal copper are used as main catalysts to adsorb, activate and dissociate hydrogen to play a role in promoting hydrogenation and dominate the catalytic activity of the catalyst, wherein the noble metal ruthenium is a key factor, and the inventor researches and discovers that when the ruthenium content in the catalyst exceeds 4.0 percent of the total weight of the catalyst, the catalytic activity of the catalyst is always in a descending trend, and the inventor preferably selects the ruthenium content to be 0.05 to 4.0 percent of the total weight of the catalyst in combination with the cost and pollution problems of the noble metal. The industrial cost of the catalyst is only 8-33% of that of the hydrogenation dechlorination catalyst containing noble metal palladium on the market.
On the basis, the inventor researches and analyzes the influence of the content of the metal copper on the catalytic activity of the noble metal ruthenium, the metal copper is used as another active component of the main catalyst and is mainly cooperated with the noble metal ruthenium to improve the catalytic activity of the catalyst, however, the research finds that the higher the adding amount of the metal copper is, the better the synergistic promotion effect is, when the copper content is more than 6.0 percent of the total weight of the catalyst, the metal copper has adverse effect on the catalytic activity and the selectivity of the catalyst, and particularly causes the selectivity of the catalyst to be greatly reduced by 5 to 15 percent. Therefore, in combination with the content of noble metal ruthenium, the content of metallic copper is required to be controlled to be 0.2-6.0 percent of the total weight of the catalyst.
The introduction of the molybdenum nitride as the auxiliary agent slightly improves the catalytic activity of the catalyst, but does not generate a large influence, but generates a remarkable influence on the selectivity of the catalyst, and on the basis of the main catalyst, the introduction of the molybdenum nitride as the auxiliary agent can improve the selectivity of the catalyst by at least 15%. After comprehensively considering factors such as production cost, effective porosity of a carrier and the like, the inventor designs that the adding amount of the molybdenum nitride is 0.5-5.0 percent of the total weight of the catalyst.
Further, the ruthenium content in the catalyst is 0.2-3.0% of the total weight of the catalyst, the copper content is 0.2-3.0% of the total weight of the catalyst, and the molybdenum nitride content is 1-3.0% of the total weight of the catalyst; the balance being carrier active carbon. The catalyst is used for the hydrogenation dechlorination of trichlorotrifluoroethane to prepare chlorotrifluoroethylene at the temperatureThe temperature is 300 ℃, and the volume space velocity of the raw material reaction gas is 300h -1 Under the reaction conditions of (3), the initial conversion rate of the trichlorotrifluoroethane is 96.6-100%, and the initial selectivity of the chlorotrifluoroethylene is 92-96.03%.
Furthermore, the content of ruthenium in the catalyst is 1.0 percent of the total weight of the catalyst, the content of copper in the catalyst is 0.5 percent of the total weight of the catalyst, and the content of molybdenum nitride in the catalyst is 3.0 percent of the total weight of the catalyst; the balance being carrier active carbon. The catalyst is used for the hydrogenation and dechlorination of trichlorotrifluoroethane to prepare chlorotrifluoroethylene, and the volume space velocity of raw material reaction gas is 300h at the temperature of 300 DEG C -1 Under the reaction conditions of (3), the initial conversion rate of the trifluorotrichloroethane is 100%, and the initial selectivity of the trifluorochloroethylene is 96.03%; after 300h of reaction time, the conversion of trifluorotrichloroethane was 97.93% and the selectivity of chlorotrifluoroethylene was 96.12%.
The preparation method of the catalyst comprises the following steps:
(1) Pre-treating a carrier; carrying out acid liquor treatment on the carrier activated carbon, washing, drying, then carrying out alkali liquor treatment, finally washing to be neutral and drying for later use;
(2) Preparation of catalyst intermediate: uniformly mixing a soluble ruthenium salt aqueous solution and a soluble copper salt aqueous solution, and dropwise adding the mixture onto pretreated carrier activated carbon for impregnation to complete the loading of a ruthenium precursor and a copper precursor of a main catalyst on the carrier activated carbon; drying to obtain a catalyst intermediate;
(3) Preparing a catalyst precursor: putting the obtained catalyst intermediate into an ammonia water solution containing ammonium molybdate and hexamethylenetetramine for impregnation, and drying after the impregnation is finished to obtain a catalyst precursor;
(4) Roasting: firstly, placing the obtained catalyst precursor at the constant temperature of 500-800 ℃ for roasting for 2-4 h under the protection of inert gas atmosphere; then placing the catalyst in hydrogen atmosphere and roasting the catalyst for 2 to 4 hours at the constant temperature of 280 to 350 ℃ to obtain the catalyst.
In the roasting process of the activated carbon impregnated with soluble ruthenium salt and soluble copper salt in the hydrogen atmosphere, ruthenium ions are reduced into metal ruthenium by virtue of the reduction action of hydrogen, copper ions are reduced into metal copper, and the metal ruthenium and the metal copper loaded activated carbon are obtained. In addition, the impregnated carrier activated carbon can enhance the interaction between the carrier and the active component ruthenium copper by roasting.
Dissolving ammonium molybdate and hexamethylenetetramine in ammonia water solution, forming a complex of molybdate ions and hexamethylenetetramine, loading the complex on activated carbon, and decomposing molybdate ions into MoO during roasting 3 Decomposition of hexamethylenetetramine to NH 3 Then NH 3 Adding MoO 3 Nitriding to obtain Mo 2 N, this process undergoes the displacement of O atoms and the insertion of N atoms. The nitriding process for the preparation of Mo 2 N is a general method.
Further, the carrier pretreatment in step (1) of the catalyst preparation method comprises the following specific operations:
a. putting the carrier activated carbon into a nitric acid solution with the volume concentration of 10-30%, and carrying out reflux treatment at the temperature of 60-120 ℃ for 2-10 h;
b. washing the activated carbon treated by the nitric acid solution to be neutral by using distilled water, and drying at the temperature of between 100 and 120 ℃ for 12 to 24 hours;
c. adding the activated carbon dried in the step b into ammonia water with the mass fraction of 5-20%, and stirring for 2-12 h at room temperature;
d. washing the activated carbon treated by the ammonia water to be neutral by using distilled water, and drying for 12-24 h at the temperature of 100-120 ℃.
After the active carbon as carrier is pretreated, most of ash, inorganic salt, various radical adsorption substances and the like on the surface and in the pore channels of the active carbon are removed, more surfaces and pore channels are exposed, and more attachment points are formed on the active components. After the acid-base pretreatment, the acid-base has a certain scouring effect on the pore passages of the activated carbon, so that the volume of the pores is increased, and the specific surface area of the carrier is increased. And after the activated carbon is pretreated by acid, surface oxygen-containing groups are increased, and the oxygen-containing functional groups can be used as the deposition center of the main catalyst, so that stable and high-dispersion metal microcrystals can be generated. The main catalyst has high dispersion degree on the surface of the carrier, and the anti-sintering capability of the catalyst is greatly improved, so that the activity and the stability of the catalyst are improved.
Further, in the preparation method of the catalyst, the concentration of the soluble ruthenium salt aqueous solution in the step (2) is 0.3-0.5 mol/L, and the concentration of the soluble copper salt aqueous solution is 0.3-1.6 mol/L; the soluble ruthenium salt is ruthenium chloride, ruthenium acetate or ruthenium nitrate; the soluble copper salt is copper chloride, copper nitrate or copper sulfate.
Further, the impregnation time of the step (2) in the catalyst preparation method is 8-12 h; the drying temperature is 80-120 ℃, and the drying time is 6-8 h.
Further, in the catalyst preparation method, the ammonia water solution containing ammonium molybdate and hexamethylenetetramine in the step (3) is prepared by mixing ammonium molybdate and hexamethylenetetramine according to a molar ratio of 1: 3-5 are dissolved in 5-20% ammonia water solution by mass percent to prepare the catalyst.
Further, the impregnation time of the step (3) in the catalyst preparation method is 6-24 h; the drying temperature is 30-80 ℃, and the drying time is 6-12 h.
Further, in the preparation method of the catalyst, the temperature in the step (4) is programmed to be 500-800 ℃ at the speed of 5-10 ℃/min; the flow rate of the inert gas is 20-40 mL/min.
Therefore, the preparation method of the catalyst has mild process conditions and simple route, and can reduce the economic investment of large-scale industrial production.
The supported hydrodechlorination catalyst or the supported hydrodechlorination catalyst prepared by the preparation method is used for preparing chlorotrifluoroethylene.
A preparation method of chlorotrifluoroethylene adopts the hydrodechlorination catalyst or the supported hydrodechlorination catalyst prepared by the preparation method, and the reaction temperature is 220-320 ℃; the raw material reaction gas is a mixed gas of hydrogen and trichlorotrifluoroethane, wherein the hydrogen in the mixed gas: the molar ratio of the trifluorotrichloroethane is 1.0-1.5: 1; the volume space velocity of the raw material reaction gas is 200-350 h -1 。
Wherein the volume space velocity of the raw material reaction gas refers to the standard cubic number of raw material reaction gas passing through each cubic meter of catalyst per hour, namely, the space velocity of the raw material gas = the volume flow of the raw material: (20℃，m 3 ▪h -1 ) Catalyst volume (m) 3 ）。
The invention has the beneficial effects that: the catalyst of the invention takes noble metal ruthenium and metal copper as main catalysts to play a role in absorbing, activating and dissociating hydrogen. On one hand, in the noble metal series such as gold, palladium, platinum, ruthenium and the like, ruthenium is low in price compared with other noble metals with better hydrogenation performance because the reserves of ruthenium in China are abundant, and the price is only 1/4-1/3 of the price of the noble metal palladium, so that the production cost can be greatly reduced by selecting ruthenium to replace palladium. On the other hand, in the process of hydrodechlorination, the reaction product contains hydrogen chloride, so that palladium can be slightly corroded, and palladium is more easily poisoned and inactivated compared with ruthenium; ruthenium can be corroded by hydrochloric acid, so that the catalytic performance of ruthenium in hydrodechlorination reaction is more stable.
On the basis of ruthenium and copper as main catalysts, molybdenum nitride is introduced into the catalyst as an auxiliary agent, so as to improve the activity and selectivity of the catalyst, particularly the selectivity of the catalyst.
Taking the catalyst for preparing chlorotrifluoroethylene by trichlorotrifluoroethane hydrodechlorination as an example, the introduction of molybdenum nitride can obviously improve the selectivity of the catalyst:
the trichlorotrifluoroethane as the reaction raw material has three C-Cl bonds, and during the catalytic hydrodechlorination reaction, the C-Cl bonds of the trichlorotrifluoroethane with the labels 1 and 2 need to be broken to generate the target product of chlorotrifluoroethylene. The introduction of the molybdenum nitride can promote the breakage of C-Cl bonds of the labels 1 and 2 to generate a target product, reduce the generation of byproducts and further greatly improve the selectivity of the chlorotrifluoroethylene. Compared with a catalyst which does not contain auxiliary agent molybdenum nitride and only consists of ruthenium, copper and carrier activated carbon, under the catalytic action of the catalyst, the conversion rate of the trifluorotrichloroethane is improved by about 3 percent, and the selectivity of the trifluorochloroethylene is improved by about 15 percent. Therefore, the molybdenum nitride can be used as an auxiliary agent to improve the activity and selectivity of the catalyst, and particularly the selectivity is more remarkable.
In addition, the molybdenum nitride has excellent poisoning resistance and low price, has relatively stable performance in the catalytic process, and does not have the phenomenon that the active center of the catalyst is reduced in the catalytic process due to easy poisoning and inactivation of metal additives such as V, bi or K.
The catalyst is used for preparing chlorotrifluoroethylene, the reaction temperature is 300 ℃ and the volume space velocity of the raw material is 300h in a reactor with the inner diameter of 15mm -1 Under the condition of (3), the initial conversion rate of trichlorotrifluoroethane as a raw material is up to 100 percent, and the selectivity of chlorotrifluoroethylene reaches 96.03 percent; after the reaction is carried out for 300 hours, the conversion rate of trichlorotrifluoroethane can still reach 97.93 percent, the selectivity of chlorotrifluoroethylene is basically stable, and the floating rate is about 1 percent. According to the use requirements of the prior industry on the hydrodechlorination catalyst (the conversion rate is more than 90 percent, and the selectivity is more than 85 percent), the service life of the catalyst can be 1000-1300 h.
In conclusion, the hydrodechlorination catalyst provided by the invention has excellent catalytic activity and selectivity, good stability and long service life, meets the industrial requirements, and is favorable for large-scale industrial production.
Drawings
FIG. 1 is a gas chromatogram of a mixed gas obtained by catalytic hydrodechlorination reaction for 300 hours in the case of chlorotrifluoroethylene prepared by using the catalyst of example 1.
Detailed Description
The technical solution of the present invention will be described in detail below with reference to the accompanying drawings.
Example 1
The content of ruthenium in the hydrodechlorination catalyst is 1.0wt% of the total weight of the catalyst, the content of copper is 0.5wt% of the total weight of the catalyst, and the content of molybdenum nitride is 3.0wt% of the total weight of the catalyst.
The preparation method of the hydrodechlorination catalyst comprises the following specific steps:
(1) Pretreatment of a carrier:
a. placing the coconut shell carbon carrier into a nitric acid solution with the volume concentration of 20%, and performing reflux treatment for 6 hours at the temperature of 80 ℃;
b. repeatedly washing the coconut shell carbon treated by nitric acid with distilled water to neutrality, and drying at 100 ℃ for 24h;
c. placing the dried coconut shell carbon into ammonia water with the mass fraction of 10%, and stirring for 12 hours at room temperature;
d. washing the coconut shell charcoal treated by the ammonia water to be neutral by using distilled water, and drying for 24 hours at 100 ℃ for later use;
(2) Preparation of catalyst intermediate:
a. weighing 0.81g of ruthenium chloride solution with the concentration of 0.43mol/L and 0.75g of copper nitrate solution with the concentration of 0.31mol/L, mixing the ruthenium chloride solution and the copper nitrate solution in 2.04g of distilled water, and carrying out ultrasonic treatment for 3min to obtain uniform mixed solution;
b. uniformly dropwise adding the mixed solution onto 3g of pretreated coconut shell carbon, carrying out ultrasonic treatment for 15min, dipping for 12h, and drying the dipped catalyst at 120 ℃ for 8h to obtain a catalyst intermediate;
(3) Preparing a catalyst precursor:
a. weighing 0.1594g of ammonium molybdate and 0.0723g of hexamethylenetetramine, dissolving in an ammonia water solution with the mass fraction of 15%, and stirring for 2 hours to obtain an ammonia water solution containing the ammonium molybdate and the hexamethylenetetramine;
b. soaking the obtained catalyst intermediate in an ammonia water solution containing ammonium molybdate and hexamethylenetetramine for 12h, and drying at 60 ℃ for 8h to obtain a catalyst precursor;
(4) Roasting: putting the catalyst precursor in a nitrogen atmosphere, heating the catalyst precursor from room temperature to 700 ℃ at the speed of 5 ℃/min, and roasting the catalyst precursor for 2 hours at the temperature of 700 ℃, wherein the flow of nitrogen is 30mL/min; and then naturally cooling to room temperature, heating to 300 ℃ at the heating rate of 5 ℃/min under the hydrogen atmosphere, introducing hydrogen at the flow rate of 15mL/min, and keeping the temperature for 4 hours to obtain the supported hydrodechlorination catalyst.
Method for preparing chlorotrifluoroethylene using the catalyst obtained in example 1:
filling the catalyst into a stainless steel reaction tube of a fixed bed catalytic device, wherein the inner diameter of the reactor is 15mm; heating to 300 deg.C at a rate of 5 deg.C/min, and heating to obtain the final productIntroducing hydrogen at the flow rate of 10mL/min, and keeping the temperature for 4h; starting a raw material trifluorotrichloroethane sample injection pump, wherein the raw material reaction gas is a mixed gas of trifluorotrichloroethane and hydrogen, and the molar ratio of the hydrogen to the trifluorotrichloroethane is 1.4; the volume space velocity of the reaction gas is 300h -1 The reaction temperature was 300 ℃.
The following gas chromatography results were obtained from FIG. 1 and are shown in Table 1.
TABLE 1 analytical results
| Peak number | Name of peak | Retention time | Peak height | Peak area | Content (wt.) | |
| 1 | Nitrogen gas | 0.323 | 3109.222 | 10443.855 | 4.2890 | / |
| 2 | Trifluoroethylene | 0.440 | 9971.667 | 6298.681 | 2.5867 | 2.76 |
| 3 | Chlorotrifluoroethylene (CTFE) | 0.557 | 40122.109 | 219398.761 | 90.1012 | 96.12 |
| 4 | Trifluorochloroethane | 0.898 | 256.556 | 1368.700 | 0.5621 | 0.60 |
| 5 | Trifluorodichloroethane | 1.032 | 106.778 | 1179.745 | 0.4845 | 0.52 |
| 6 | Trifluorotrichloroethane (CFC-113) | 1.590 | 772.053 | 4812.8 | 1.9765 | / |
| In total | 54338.384 | 243502.596 | 100.000 |
Wherein the conversion rate of trichlorotrifluoroethane =1- (CFC-113 peak area/sum of all peak areas except nitrogen) = 1-4812.8/(6298.681 +219398.761+1368.7+1179.745+ 4812.8) =97.93%.
Chlorotrifluoroethylene selectivity = product peak area/total product peak area = 219398.761/(6298.681 +219398.761+1368.7+ 1179.745) =96.12%.
Example 2
In the supported hydrodechlorination catalyst, the content of ruthenium is 0.05wt% of the total weight of the catalyst, the content of copper is 0.5wt% of the total weight of the catalyst, and the content of molybdenum nitride is 3.0wt% of the total weight of the catalyst.
The preparation method of the hydrodechlorination catalyst comprises the following specific steps:
(1) Pretreatment of a carrier:
a. placing the coconut shell carbon carrier into a nitric acid solution with the volume concentration of 10%, and carrying out reflux treatment for 2h at the temperature of 60 ℃;
b. repeatedly washing the coconut shell carbon treated by nitric acid with distilled water to neutrality, and drying at 100 ℃ for 12h;
c. placing the dried coconut shell carbon into 5% ammonia water by mass percent, and stirring for 2 hours at room temperature;
d. washing the coconut shell charcoal treated by the ammonia water to be neutral by using distilled water, and drying for 12 hours at 100 ℃ for later use;
(2) Preparation of catalyst intermediate:
a. weighing 0.0405g of ruthenium chloride solution with the concentration of 0.43mol/L and 0.75g of copper nitrate solution with the concentration of 0.31mol/L, mixing the solution in 2.81g of distilled water, and carrying out ultrasonic treatment for 3min to obtain uniform mixed solution;
b. uniformly dropwise adding the mixed solution onto 3g of pretreated coconut shell carbon, carrying out ultrasonic treatment for 15min, soaking for 8h, and drying the soaked catalyst at 80 ℃ for 6h to obtain a catalyst intermediate;
(3) Preparing a catalyst precursor:
a. weighing 0.1594g of ammonium molybdate and 0.0723g of hexamethylenetetramine, dissolving in an ammonia water solution with the mass fraction of 15%, and stirring for 2 hours to obtain an ammonia water solution containing the ammonium molybdate and the hexamethylenetetramine;
b. soaking the obtained catalyst intermediate in an ammonia water solution containing ammonium molybdate and hexamethylenetetramine for 6h, and drying at 30 ℃ for 6h to obtain a catalyst precursor;
(4) Roasting: putting the catalyst precursor in a nitrogen atmosphere, heating the catalyst precursor from room temperature to 500 ℃ at the speed of 5 ℃/min, and roasting the catalyst precursor for 2 hours at the temperature of 500 ℃, wherein the flow of nitrogen is 20mL/min; and then heating to 280 ℃ at the heating rate of 5 ℃/min under the hydrogen atmosphere, introducing hydrogen at the flow rate of 15mL/min, and keeping the temperature for 2 hours to obtain the supported hydrodechlorination catalyst.
The process for preparing chlorotrifluoroethylene using this catalyst is the same as in example 1.
Example 3
In the supported hydrodechlorination catalyst, the content of ruthenium is 0.2wt% of the total weight of the catalyst, the content of copper is 0.5wt% of the total weight of the catalyst, and the content of molybdenum nitride is 3.0wt% of the total weight of the catalyst.
The catalyst was prepared in the same manner as in example 1 except that in this example, 0.17g of a ruthenium chloride solution having a concentration of 0.43mol/L and 0.75g of a copper nitrate solution having a concentration of 0.31mol/L were weighed and mixed in 2.68g of distilled water.
The process for preparing chlorotrifluoroethylene using this catalyst is the same as in example 1.
Example 4
In the supported hydrodechlorination catalyst, the content of ruthenium is 1.5wt% of the total weight of the catalyst, the content of copper is 0.5wt% of the total weight of the catalyst, and the content of molybdenum nitride is 3.0wt% of the total weight of the catalyst.
The preparation method of the hydrodechlorination catalyst comprises the following specific steps:
(1) Pretreatment of a carrier:
a. placing the coconut shell carbon carrier into a nitric acid solution with the volume concentration of 30%, and performing reflux treatment for 10 hours at 120 ℃;
b. repeatedly washing the coconut shell carbon treated by nitric acid with distilled water to neutrality, and drying at 120 ℃ for 24h;
c. placing the dried coconut shell carbon into ammonia water with the mass fraction of 20%, and stirring for 12 hours at room temperature;
d. washing the coconut shell charcoal treated by the ammonia water to be neutral by using distilled water, and drying for 24 hours at 120 ℃ for later use;
(2) Preparation of catalyst intermediate:
a. weighing 1.22g of ruthenium chloride solution with the concentration of 0.43mol/L and 0.75g of copper nitrate solution with the concentration of 0.31mol/L, mixing the ruthenium chloride solution and the copper nitrate solution in 1.63g of distilled water, and carrying out ultrasonic treatment for 3min to obtain uniform mixed solution;
b. uniformly dropwise adding the mixed solution onto 3g of pretreated coconut shell carbon, carrying out ultrasonic treatment for 15min, dipping for 12h, and drying the dipped catalyst at 120 ℃ for 8h to obtain a catalyst intermediate;
(3) Preparing a catalyst precursor:
a. weighing 0.1594g of ammonium molybdate and 0.0723g of hexamethylenetetramine, dissolving in an ammonia solution with the mass fraction of 15%, and stirring for 2 hours to obtain an ammonia solution containing the ammonium molybdate and the hexamethylenetetramine;
b. soaking the obtained catalyst intermediate in an ammonia water solution containing ammonium molybdate and hexamethylenetetramine for 24 hours, and drying at 80 ℃ for 12 hours to obtain a catalyst precursor;
(4) Roasting: putting the catalyst precursor in a nitrogen atmosphere, heating the catalyst precursor from room temperature to 800 ℃ at the speed of 10 ℃/min, and roasting the catalyst precursor for 4 hours at the temperature of 800 ℃, wherein the flow of nitrogen is 40mL/min; then naturally cooling to room temperature; and then heating to 350 ℃ at the heating rate of 10 ℃/min under the hydrogen atmosphere, introducing hydrogen at the flow rate of 15mL/min, and keeping the temperature for 4 hours to obtain the supported hydrodechlorination catalyst.
The process for preparing chlorotrifluoroethylene using this catalyst is the same as in example 1.
Example 5
In the supported hydrodechlorination catalyst, the content of ruthenium is 3.0wt% of the total weight of the catalyst, the content of copper is 0.5wt% of the total weight of the catalyst, and the content of molybdenum nitride is 3.0wt% of the total weight of the catalyst.
The catalyst was prepared in the same manner as in example 1 except that in this example, 2.44g of a ruthenium chloride solution having a concentration of 0.43mol/L and 0.75g of a copper nitrate solution having a concentration of 0.31mol/L were weighed and mixed in 0.45g of distilled water.
The process for preparing chlorotrifluoroethylene using this catalyst is the same as in example 1.
Example 6
In the supported hydrodechlorination catalyst, the content of ruthenium is 4.0wt% of the total weight of the catalyst, the content of copper is 0.5wt% of the total weight of the catalyst, and the content of molybdenum nitride is 3.0wt% of the total weight of the catalyst.
The catalyst was prepared in the same manner as in example 1 except that in this example, 1.62g of a ruthenium chloride solution having a concentration of 0.86mol/L and 0.75g of a copper nitrate solution having a concentration of 0.31mol/L were weighed and mixed in 1.23g of distilled water.
The process for preparing chlorotrifluoroethylene using this catalyst is the same as in example 1.
Example 7
In the supported hydrodechlorination catalyst, the content of ruthenium accounts for 1.0wt% of the total weight of the catalyst, the content of copper accounts for 0.3wt% of the total weight of the catalyst, and the content of molybdenum nitride accounts for 3.0wt% of the total weight of the catalyst.
The catalyst was prepared in the same manner as in example 1 except that in this example, 0.81g of a ruthenium chloride solution having a concentration of 0.43mol/L and 0.45g of a copper nitrate solution having a concentration of 0.31mol/L were weighed and mixed in 2.34g of distilled water.
The process for preparing chlorotrifluoroethylene using this catalyst is the same as in example 1.
Example 8
In the supported hydrodechlorination catalyst, the content of ruthenium is 1.0wt% of the total weight of the catalyst, the content of copper is 1.0wt% of the total weight of the catalyst, and the content of molybdenum nitride is 3.0wt% of the total weight of the catalyst.
The catalyst was prepared in the same manner as in example 1 except that in this example, 0.81g of a ruthenium chloride solution having a concentration of 0.43mol/L and 1.5g of a copper nitrate solution having a concentration of 0.31mol/L were weighed and mixed in 1.29g of distilled water.
The process for preparing chlorotrifluoroethylene using this catalyst is the same as in example 1.
Example 9
In the supported hydrodechlorination catalyst, the content of ruthenium is 1.0wt% of the total weight of the catalyst, the content of copper is 3.0wt% of the total weight of the catalyst, and the content of molybdenum nitride is 3.0wt% of the total weight of the catalyst.
The catalyst was prepared in the same manner as in example 1 except that in this example, 0.81g of a ruthenium chloride solution having a concentration of 0.43mol/L and 1.5g of a copper nitrate solution having a concentration of 0.93mol/L were weighed and mixed in 1.29g of distilled water.
The process for preparing chlorotrifluoroethylene using this catalyst is the same as in example 1.
Example 10
In the supported hydrodechlorination catalyst, the content of ruthenium is 1.0wt% of the total weight of the catalyst, the content of copper is 6.0wt% of the total weight of the catalyst, and the content of molybdenum nitride is 3.0wt% of the total weight of the catalyst.
The catalyst was prepared in the same manner as in example 1 except that in this example, 0.81g of a ruthenium chloride solution having a concentration of 0.43mol/L and 1.50g of a copper nitrate solution having a concentration of 1.86mol/L were weighed and mixed in 1.29g of distilled water.
The process for preparing chlorotrifluoroethylene using this catalyst is the same as in example 1.
Example 11
In the supported hydrodechlorination catalyst, the content of ruthenium is 1.0wt% of the total weight of the catalyst, the content of copper is 0.5wt% of the total weight of the catalyst, and the content of molybdenum nitride is 0.5wt% of the total weight of the catalyst.
The preparation method of the catalyst is the same as that in example 1, except that in this example, 0.0266g of ammonium molybdate and 0.0121g of hexamethylenetetramine are dissolved in 15% ammonia solution by mass fraction, and the solution is stirred for 2 hours to obtain the ammonia solution containing ammonium molybdate and hexamethylenetetramine.
The process for preparing chlorotrifluoroethylene using this catalyst is the same as in example 1.
Example 12
In the supported hydrodechlorination catalyst, the content of ruthenium is 1.0wt% of the total weight of the catalyst, the content of copper is 0.5wt% of the total weight of the catalyst, and the content of molybdenum nitride is 1.0wt% of the total weight of the catalyst.
The preparation method of the catalyst is the same as that in example 1, except that in this example, 0.0531g of ammonium molybdate and 0.0241g of hexamethylenetetramine are weighed and dissolved in an ammonia water solution with the mass fraction of 15%, and the solution is stirred for 2 hours to obtain the ammonia water solution containing ammonium molybdate and hexamethylenetetramine.
The process for preparing chlorotrifluoroethylene using this catalyst is the same as in example 1.
Example 13
In the supported hydrodechlorination catalyst, the content of ruthenium accounts for 1.0wt% of the total weight of the catalyst, the content of copper accounts for 0.5wt% of the total weight of the catalyst, and the content of molybdenum nitride accounts for 5.0wt% of the total weight of the catalyst.
The preparation method of the catalyst is the same as that in example 1, except that in this example, 0.2657g of ammonium molybdate and 0.1205g of hexamethylenetetramine are weighed and dissolved in an ammonia solution with the mass fraction of 15%, and the solution is stirred for 2 hours to obtain the ammonia solution containing the ammonium molybdate and the hexamethylenetetramine.
The process for preparing chlorotrifluoroethylene using this catalyst is the same as in example 1.
Example 14
In the supported hydrodechlorination catalyst, the content of ruthenium accounts for 1.0wt% of the total weight of the catalyst, the content of copper accounts for 0.5wt% of the total weight of the catalyst, and the content of molybdenum nitride accounts for 3.0wt% of the total weight of the catalyst.
The catalyst preparation method was the same as in example 1, except that the calcination temperature of the catalyst precursor in the catalyst preparation method of this example was 600 ℃.
The process for preparing chlorotrifluoroethylene using this catalyst is the same as in example 1.
Example 15
In the supported hydrodechlorination catalyst, the content of ruthenium is 1.0wt% of the total weight of the catalyst, the content of copper is 0.5wt% of the total weight of the catalyst, and the content of molybdenum nitride is 3.0wt% of the total weight of the catalyst.
The catalyst preparation method was the same as in example 1, except that the calcination temperature of the catalyst precursor in the catalyst preparation method of this example was 800 ℃.
The process for preparing chlorotrifluoroethylene using this catalyst is the same as in example 1.
Example 16
The content of ruthenium in the hydrodechlorination catalyst is 1.0wt% of the total weight of the catalyst, the content of copper is 0.5wt% of the total weight of the catalyst, and the content of molybdenum nitride is 3.0wt% of the total weight of the catalyst.
The catalyst was prepared in the same manner as in example 1 except that the soluble ruthenium salt used in the catalyst preparation method of this example was ruthenium acetate, and 0.81g of a ruthenium acetate solution having a concentration of 0.395mol/L and 0.75g of a copper nitrate solution having a concentration of 0.93mol/L were weighed and mixed in 2.04g of distilled water.
The process for preparing chlorotrifluoroethylene using this catalyst is the same as in example 1.
Example 17
In the hydrodechlorination catalyst, the content of ruthenium is 1.0wt% of the total weight of the catalyst, the content of copper is 0.5wt% of the total weight of the catalyst, and the content of molybdenum nitride is 3.0wt% of the total weight of the catalyst.
The catalyst was prepared in the same manner as in example 1 except that the soluble ruthenium salt used in the catalyst preparation method of this example was ruthenium nitrate, and 0.81g of a ruthenium nitrate solution having a concentration of 0.396mol/L and 0.75g of a copper nitrate solution having a concentration of 0.93mol/L were weighed and mixed in 2.04g of distilled water.
The process for preparing chlorotrifluoroethylene using this catalyst is the same as in example 1.
Example 18
The content of ruthenium in the hydrodechlorination catalyst is 1.0wt% of the total weight of the catalyst, the content of copper is 0.5wt% of the total weight of the catalyst, and the content of molybdenum nitride is 3.0wt% of the total weight of the catalyst.
The preparation method of the catalyst was the same as that of example 1, except that the soluble copper salt used in the preparation method of the catalyst of this example was copper chloride, and 0.81g of a ruthenium chloride solution having a concentration of 0.43mol/L and 0.75g of a copper chloride solution having a concentration of 1.94mol/L were weighed and mixed in 2.04g of distilled water.
The process for preparing chlorotrifluoroethylene using this catalyst is the same as in example 1.
Example 19
In the hydrodechlorination catalyst, the content of ruthenium is 1.0wt% of the total weight of the catalyst, the content of copper is 0.5wt% of the total weight of the catalyst, and the content of molybdenum nitride is 3.0wt% of the total weight of the catalyst.
The preparation method of the catalyst is the same as that of example 1, except that the soluble copper salt used in the preparation method of the catalyst in this example is copper sulfate, and 0.81g of ruthenium chloride solution with a concentration of 0.43mol/L and 0.75g of copper sulfate solution with a concentration of 1.92mol/L are weighed and mixed in 2.04g of distilled water.
The process for preparing chlorotrifluoroethylene using this catalyst is the same as in example 1.
Example 20
In the supported hydrodechlorination catalyst, the content of ruthenium is 1.0wt% of the total weight of the catalyst, the content of copper is 0.5wt% of the total weight of the catalyst, and the content of molybdenum nitride is 3.0wt% of the total weight of the catalyst.
The catalyst was prepared as in example 1.
The method for preparing chlorotrifluoroethylene using the catalyst was the same as example 1 except that the reaction temperature used for preparing chlorotrifluoroethylene in this example was 220 ℃.
Example 21
In the supported hydrodechlorination catalyst, the content of ruthenium is 1.0wt% of the total weight of the catalyst, the content of copper is 0.5wt% of the total weight of the catalyst, and the content of molybdenum nitride is 3.0wt% of the total weight of the catalyst.
The catalyst was prepared as in example 1.
The method for preparing chlorotrifluoroethylene using the catalyst was the same as example 1, except that the reaction temperature used for preparing chlorotrifluoroethylene in this example was 320 ℃.
Example 22
In the supported hydrodechlorination catalyst, the content of ruthenium is 1.0wt% of the total weight of the catalyst, the content of copper is 0.5wt% of the total weight of the catalyst, and the content of molybdenum nitride is 3.0wt% of the total weight of the catalyst.
The catalyst was prepared as in example 1.
The method for preparing chlorotrifluoroethylene using the catalyst is the same as that of example 1, except that the hydrogen in the mixed gas used for preparing chlorotrifluoroethylene in this example: the molar ratio of trifluorotrichloroethane is 1.
Example 23
In the supported hydrodechlorination catalyst, the content of ruthenium is 1.0wt% of the total weight of the catalyst, the content of copper is 0.5wt% of the total weight of the catalyst, and the content of molybdenum nitride is 3.0wt% of the total weight of the catalyst.
The catalyst was prepared as in example 1.
The method for preparing chlorotrifluoroethylene using the catalyst is the same as that of example 1, except that the hydrogen in the mixed gas used for preparing chlorotrifluoroethylene in this example: the molar ratio of trifluorotrichloroethane was 1.5.
Example 24
In the supported hydrodechlorination catalyst, the content of ruthenium is 1.0wt% of the total weight of the catalyst, the content of copper is 0.5wt% of the total weight of the catalyst, and the content of molybdenum nitride is 3.0wt% of the total weight of the catalyst.
The catalyst was prepared as in example 1.
The method for preparing chlorotrifluoroethylene using the catalyst is the same as that of example 1, except that the volume space velocity of the raw material reaction gas used for preparing chlorotrifluoroethylene in this example is 200h -1 。
Example 25
In the supported hydrodechlorination catalyst, the content of ruthenium is 1.0wt% of the total weight of the catalyst, the content of copper is 0.5wt% of the total weight of the catalyst, and the content of molybdenum nitride is 3.0wt% of the total weight of the catalyst.
The catalyst was prepared as in example 1.
The method for preparing chlorotrifluoroethylene by using the catalyst is the same as that of example 1, except that the volume space velocity of the raw material reaction gas for preparing chlorotrifluoroethylene in this example is 350h -1 。
Comparative example 1
In the supported hydrodechlorination catalyst described in this comparative example, the ruthenium content was 1.0wt% based on the total weight of the catalyst, the copper content was 8.0wt% based on the total weight of the catalyst, and the molybdenum nitride content was 3.0wt% based on the total weight of the catalyst.
Comparative example 2
In the supported hydrodechlorination catalyst of the comparative example, the ruthenium content was 1.0wt% and the copper content was 0.5wt% of the total weight of the catalyst; molybdenum nitride is not added as an auxiliary agent.
The catalyst was prepared according to the same method as in example 1, except that the impregnation supporting aid of step (3) of the method of example 1 was not used, and the catalyst intermediate was prepared and then directly calcined.
Comparative example 3
The main catalysts of the hydrodechlorination catalyst in the comparative example are noble metal Pd and metal Cu, wherein the content of Pd is 1.0wt% of the total weight of the catalyst, and the content of copper is 0.5wt% of the total weight of the catalyst; the content of the molybdenum nitride is 3.0wt% of the total weight of the catalyst.
Comparative example 4
The main catalysts of the hydrodechlorination catalyst of the comparative example are noble metal Pt and metal Cu, wherein the content of Pt is 1.0wt% of the total weight of the catalyst, the content of copper is 0.5wt% of the total weight of the catalyst, and the content of molybdenum nitride is 3.0wt% of the total weight of the catalyst.
Comparative example 5
In the supported hydrodechlorination catalyst of the comparative example, the auxiliary agents are metal lanthanum and alkali metal lithium; the content of ruthenium in the catalyst is 1.0wt% of the total weight of the catalyst, the content of copper is 0.5wt% of the total weight of the catalyst, and the content of metal lanthanum and alkali metal lithium is 3.0wt% of the total weight of the catalyst, wherein the mass ratio of the metal lanthanum to the alkali metal lithium is 1.
Comparative example 6
In the supported hydrodechlorination catalyst of the comparative example, the auxiliary agent is VCl 3 (ii) a The ruthenium content in the catalyst was 1.0wt% based on the total weight of the catalyst, the copper content was 0.5wt% based on the total weight of the catalyst, VCl 3 The content was 3.0wt% based on the total weight of the catalyst.
Comparative example 7
In the load type hydrodechlorination catalyst of the comparative example, the auxiliary agent is molybdenum nitrate; in the catalyst, the content of ruthenium was 1.0wt%, the content of copper was 0.5wt%, and the content of molybdenum nitrate was 3.0wt%.
Comparative example 8
The other points are the same as example 1, except that the preparation method of the catalyst in the comparative example has different sequences of acid treatment and alkali treatment when coconut shell ash is pretreated, specifically:
adding the coconut shell carbon into ammonia water with the mass fraction of 10%, and stirring for 12h at room temperature;
washing with distilled water to neutrality, and drying at 100 deg.C for 24 hr;
then adding the mixture into nitric acid solution with the volume concentration of 20%, and carrying out reflux treatment for 6h at the temperature of 80 ℃;
repeatedly washing with distilled water to neutrality, and drying at 100 deg.C for 24 hr to obtain treated coconut shell charcoal.
Comparative example 9
The catalyst of this comparative example only supported molybdenum nitride on the supported activated carbon in an amount of 3.0wt% based on the total weight of the catalyst.
The catalysts prepared in the respective examples and comparative examples were used for the preparation of chlorotrifluoroethylene, and the conversion of the starting trifluorotrichloroethane and the selectivity of the objective chlorotrifluoroethylene were obtained by gas chromatography analysis under the catalytic action of the respective catalysts.
1. Experimental methods
1. Each 1g of the catalysts prepared in the above examples and comparative examples was weighed, and the catalysts were packed in a stainless steel reaction tube of a fixed bed catalytic unit, the inner diameter of the reactor being 15mm. Then heating to 300 ℃ at the heating rate of 5 ℃/min, introducing hydrogen at the flow rate of 10mL/min, and keeping the temperature at 4 DEG Ch, opening a raw material trifluorotrichloroethane sample injection pump after reduction at an airspeed of 300h -1 The molar ratio of hydrogen to trifluorotrichloroethane was 1.5 and the reaction temperature was 300 ℃.
2. Analyzing the mixed gas after the catalytic hydrogenation reaction by adopting Jiemio GC1690 gas chromatography: the column box of the gas chromatograph is 180 ℃, the sample introduction temperature is 120 ℃, the thermal conductivity temperature is 180 ℃, and a TCD detector is used. And (3) replacing and extracting 0.6mL of the mixed gas subjected to acid and alkali removal for multiple times by using a micro sample injector, injecting the mixed gas through a sample injection pad, and simultaneously carrying out data acquisition, wherein the carrier gas is high-purity hydrogen.
2. Analysis of Experimental data
The conversion of trifluorotrichloroethane and the selectivity of the product were calculated by area normalization (all products were peaked) as follows:
conversion rate (%) of trifluorotrichloroethane (= raw trifluorotrichloroethane peak area/sum of all peak areas excluding nitrogen gas) × 100;
selectivity of chlorotrifluoroethylene (%) = peak area of chlorotrifluoroethylene of target product/sum of peak areas of all products × 100.
The gas chromatography analysis and measurement were performed on the reacted mixture gas at the beginning of the catalytic hydrogenation reaction and after 300 hours of continuous reaction, to obtain conversion and selectivity data, and the results are shown in tables 2 and 3.
TABLE 2 Trifluorotrichloroethane conversion and chlorotrifluoroethylene selectivity with different catalysts
| Catalyst and process for producing the same | Airspeed (h-1) | Trifluorotrichloroethane Initial conversion (%) | Chlorotrifluoroethylene precursor Initial selectivity (%) | After 300 hours trifluorotrichloroethane Conversion (%) | Chlorotrifluoroethylene after 300 hours Selectivity (%) |
| Example 1 | 300 | 100 | 96.03 | 97.93 | 96.12 |
| Example 2 | 300 | 96.43 | 91.21 | 89.56 | 91.83 |
| Example 3 | 300 | 97.78 | 92.76 | 95.02 | 92.88 |
| Example 4 | 300 | 96.18 | 91.68 | 94.17 | 91.22 |
| Example 5 | 300 | 98.12 | 92.12 | 94.56 | 92.13 |
| Example 6 | 300 | 96.56 | 90.12 | 90.74 | 91.56 |
| Example 7 | 300 | 98.56 | 93.23 | 96.08 | 93.11 |
| Example 8 | 300 | 97.77 | 89.05 | 81.43 | 89.66 |
| Example 9 | 300 | 96.59 | 86.12 | 80.32 | 86.31 |
| Example 10 | 300 | 96.11 | 81.11 | 82.07 | 81.86 |
| Example 11 | 300 | 97.56 | 86.23 | 86.65 | 87.11 |
| Example 12 | 300 | 98.78 | 92.06 | 94.29 | 91.69 |
| Example 13 | 300 | 97.45 | 93.56 | 94.74 | 93.48 |
| Example 14 | 300 | 98.07 | 92.01 | 89.23 | 92.34 |
| Example 15 | 300 | 96.78 | 90.08 | 86.37 | 90.66 |
| Example 16 | 300 | 98.36 | 91.33 | 87.58 | 91.73 |
| Example 17 | 300 | 97.57 | 92.12 | 89.56 | 89.55 |
| Example 18 | 300 | 98.12 | 93.93 | 97.53 | 93.66 |
| Example 19 | 300 | 97.98 | 92.45 | 96.75 | 90.37 |
| Comparative example 1 | 300 | 96.06 | 80.33 | 83.56 | 80.78 |
| Comparative example 2 | 300 | 96.56 | 80.12 | 82.51 | 80.56 |
| Comparative example 3 | 300 | 98.09 | 93.93 | 97.59 | 92.67 |
| Comparative example 4 | 300 | 97.78 | 92.45 | 96.77 | 91.36 |
| Comparative example 5 | 300 | 98.03 | 92.85 | 98.34 | 91.89 |
| Comparative example 6 | 300 | 98.45 | 92.67 | 98.12 | 92.43 |
| Comparative example 7 | 300 | 97.45 | 91.89 | 97.22 | 91.07 |
| Comparative example 8 | 300 | 98.23 | 93.28 | 96.68 | 93.12 |
| Comparative example 9 | 300 | 42.23 | 83.28 | 36.39 | 83.12 |
TABLE 3 Trifluorotrichloroethane conversion and chlorotrifluoroethylene selectivity for the preparation of chlorotrifluoroethylene using the catalyst described in example 1 under different reaction conditions
| Catalyst and process for preparing same | Airspeed (h-1) | Temperature of （℃） | Hydrogen and trifluoro Process for preparing trichloroethane Molar ratio of | Trifluorotrichloro compounds Ethane initiation Conversion (%) | Chlorotrifluoroethylene precursor Initial selectivity (%) | Trifluorotrifluoro after 300 hours Ethyl chloride conversion (%) | Trifluoro after 300 hours Vinyl chloride Selectivity (%) |
| Example 1 | 300 | 300 | 1.4:1 | 100 | 96.03 | 97.93 | 96.12 |
| Examples 20 | 300 | 220 | 1.4:1 | 86.43 | 96.21 | 83.56 | 92.34 |
| Examples 21 | 300 | 320 | 1.4:1 | 100 | 96.92 | 94.63 | 92.95 |
| Examples 22 | 300 | 300 | 1:1 | 82.52 | 95.72 | 78.74 | 93.28 |
| Examples 23 | 300 | 300 | 1.5:1 | 100 | 95.51 | 97.71 | 95.53 |
| Examples 24 | 200 | 300 | 1.4:1 | 100 | 95.98 | 98.02 | 95.72 |
| Examples 25 | 350 | 300 | 1.4:1 | 98.22 | 91.12 | 92.76 | 90.31 |
(1) As can be seen from the comparison of the data of example 3 and comparative examples 3 and 4 in Table 2, under the same catalytic effect, the noble metal loading of the combination of ruthenium, copper and molybdenum nitride is the smallest and is only 20% of the noble metal loading of palladium/platinum when the three noble metals of ruthenium, palladium and platinum are combined with the same amount of copper and molybdenum nitride.
(2) As can be seen from the comparison of the chlorotrifluoroethylene selectivity data of examples 1, 7-10 and comparative example 1 in Table 2, the catalytic activity and selectivity of the catalyst peaked at 0.5wt% copper in the catalyst with the same addition of ruthenium and molybdenum nitride.
(3) As can be seen from the comparison of the trifluorotrichloroethane conversion and the chlorotrifluoroethylene selectivity data of example 1 and comparative example 2 in table 2, the chlorotrifluoroethylene selectivity increased by 15.91% with the catalyst with the addition of the auxiliary molybdenum nitride compared to the catalyst without the addition of the molybdenum nitride. Although the initial conversion rate of the trifluorotrichloroethane is improved by only 3.44% by adding the molybdenum nitride, the data of the trifluorotrichloroethane conversion rate after 300h of reaction is compared, the conversion rate of the trifluorotrichloroethane is reduced by only 2.07% after 300h by using the catalyst with the molybdenum nitride, the conversion rate of the trifluorotrichloroethane is reduced by 14.05% after 300h by using the catalyst without the molybdenum nitride, and the stability of the catalyst can be obviously improved by using the auxiliary agent molybdenum nitride.
(4) As can be seen from the comparison of the data of example 1 and comparative examples 5, 6 and 7 in Table 2, the molybdenum nitride promoter is more beneficial to improving the catalytic performance of the catalyst, especially the selectivity of the catalyst, compared with other promoters.
(5) As can be seen from the comparison of the data of example 1 and comparative example 9 in Table 2, the promoter molybdenum nitride has low activity in the aspect of activating and dissociating hydrogen in the hydrodechlorination reaction, but has high catalytic selectivity for the generation of the target product chlorotrifluoroethylene.
(6) From the data of trifluorotrichloroethane conversion and chlorotrifluoroethylene selectivity of example 1, example 14 and example 15, it can be seen that the calcination temperature affects the catalytic activity and stability of the catalyst, and that the catalytic activity and selectivity of the catalyst are higher at the calcination temperature of 700 ℃. The roasting temperature influences the interaction between the active component and the carrier and the dispersion degree of the active component, and has great influence on the activity and stability of the catalyst, the dispersion degree of the main catalyst and the auxiliary agent is better at the roasting temperature of 700 ℃, the main catalyst and the auxiliary agent are not easy to agglomerate in the reaction process, and the activity and the stability of the catalyst are higher than those of the catalyst obtained at other roasting temperatures.
(7) From the trifluorotrichloroethane conversion and chlorotrifluoroethylene selectivity data of example 1 and comparative example 8, it can be seen that the different order of acid and base pretreatment of the support affects the catalytic activity and selectivity of the catalyst. The acid treatment and the alkali treatment are beneficial to improving the catalytic activity and the selectivity of the catalyst.
Claims (10)
1. A load type hydrodechlorination catalyst is characterized in that a main catalyst of the catalyst is ruthenium and copper, an auxiliary agent is molybdenum nitride, and a carrier is activated carbon;
the catalyst is prepared by the following steps:
(1) Pretreatment of a carrier: firstly, carrying out acid liquor treatment on carrier activated carbon, washing, drying, then carrying out alkali liquor treatment, and finally washing to be neutral and drying for later use;
(2) Preparation of catalyst intermediate: uniformly mixing a soluble ruthenium salt aqueous solution and a soluble copper salt aqueous solution, and dropwise adding the mixture onto pretreated carrier activated carbon for impregnation to complete the loading of a ruthenium precursor and a copper precursor of a main catalyst on the carrier activated carbon; drying to obtain a catalyst intermediate;
(3) Preparing a catalyst precursor: putting the obtained catalyst intermediate into an ammonia water solution containing ammonium molybdate and hexamethylenetetramine for impregnation, and drying after the impregnation is finished to obtain a catalyst precursor;
(4) Roasting: firstly, placing the obtained catalyst precursor at the constant temperature of 500-800 ℃ for roasting for 2-4 h under the protection of inert gas atmosphere; then placing the mixture at the temperature of 280-350 ℃ for constant-temperature roasting for 2-4 hours in the hydrogen atmosphere to obtain the catalyst.
2. The supported hydrodechlorination catalyst of claim 1, wherein the ruthenium content of the catalyst is 0.05 to 4.0% of the total weight of the catalyst, the copper content is 0.2 to 6.0% of the total weight of the catalyst, and the molybdenum nitride content is 0.5 to 5.0% of the total weight of the catalyst; the balance being carrier active carbon.
3. The supported hydrodechlorination catalyst of claim 2, wherein the ruthenium content of the catalyst is 0.2 to 3.0% by weight, the copper content of the catalyst is 0.2 to 3.0% by weight, and the molybdenum nitride content of the catalyst is 1 to 3.0% by weight; the balance being carrier active carbon.
4. The supported hydrodechlorination catalyst of claim 3, wherein the catalyst comprises 1.0wt% ruthenium, 0.5wt% copper, and 3.0wt% molybdenum nitride, based on the total weight of the catalyst; the balance being carrier active carbon.
5. The supported hydrodechlorination catalyst of claim 1, wherein the carrier pretreatment of step (1) is performed by:
a. putting the carrier activated carbon into a nitric acid solution with the volume concentration of 10-30%, and carrying out reflux treatment at the temperature of 60-120 ℃ for 2-10 h;
b. washing the activated carbon treated by the nitric acid solution to be neutral by using distilled water, and drying for 12-24 h at the temperature of 100-120 ℃;
c. b, putting the activated carbon dried in the step b into ammonia water with the mass fraction of 5-20%, and stirring for 2-12 h at room temperature;
d. washing the activated carbon treated by the ammonia water to be neutral by using distilled water, and drying for 12-24 h at the temperature of 100-120 ℃.
6. The supported hydrodechlorination catalyst according to claim 1, wherein the concentration of the soluble ruthenium salt aqueous solution in the step (2) is 0.3 to 0.5mol/L, and the concentration of the soluble copper salt aqueous solution is 0.3 to 1.6mol/L;
the soluble ruthenium salt is ruthenium chloride, ruthenium acetate or ruthenium nitrate; the soluble copper salt is copper chloride, copper nitrate or copper sulfate;
the dipping time in the step (2) is 8-12 h; the drying temperature is 80-120 ℃, and the drying time is 6-8 h.
7. The supported hydrodechlorination catalyst according to claim 1, wherein the aqueous ammonia solution containing ammonium molybdate and hexamethylenetetramine in the step (3) is prepared by mixing ammonium molybdate and hexamethylenetetramine in a molar ratio of 1: 3-5 are dissolved in ammonia water solution with the mass fraction of 5-20 percent to prepare the product;
the dipping time in the step (3) is 6-24 h; the drying temperature is 30-80 ℃, and the drying time is 6-12 h.
8. The supported hydrodechlorination catalyst of claim 1, wherein in step (4) the temperature is programmed to a calcination temperature of 500-800 ℃ at a rate of 5-10 ℃/min; the flow rate of the inert gas is 20-40 mL/min.
9. Use of a supported hydrodechlorination catalyst according to any one of claims 1 to 8, in the preparation of chlorotrifluoroethylene.
10. A method for preparing chlorotrifluoroethylene, characterized in that a supported hydrodechlorination catalyst according to any one of claims 1 to 8 is used, and the reaction temperature is 220 to 320 ℃; the raw material reaction gas is a mixed gas of hydrogen and trichlorotrifluoroethane, wherein the hydrogen in the mixed gas: the molar ratio of the trifluorotrichloroethane is 1.0-1.5; the volume space velocity of the raw material reaction gas is 200-350 h -1 。
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Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1351903A (en) * | 2001-11-07 | 2002-06-05 | 大连明辰振邦氟涂料股份有限公司 | Catalystic hydrogenation and dechlorination catalyst for preparing trifluorochloroethylene and trichloroethylene |
| CN105457651A (en) * | 2014-09-05 | 2016-04-06 | 浙江蓝天环保高科技股份有限公司 | Hydrodechlorination catalyst and application thereof in preparation of chlorotrifluoroethylene |
| KR20180003666A (en) * | 2016-06-30 | 2018-01-10 | 연세대학교 산학협력단 | A semiconductor device and a method of fabricating the same |
| CN109603707A (en) * | 2018-12-26 | 2019-04-12 | 大连海事大学 | A kind of CH4/CO2Low temperature directly synthesizes the device and its synthetic method of C1-C4 alcohol |
| CN111013604A (en) * | 2019-11-21 | 2020-04-17 | 浙江工业大学 | Catalyst for catalytic hydrodechlorination and preparation method and application thereof |
| CN112569996A (en) * | 2020-12-10 | 2021-03-30 | 中化蓝天集团有限公司 | Catalyst for preparing perhalogenated ethylene and preparation method and application thereof |
-
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Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1351903A (en) * | 2001-11-07 | 2002-06-05 | 大连明辰振邦氟涂料股份有限公司 | Catalystic hydrogenation and dechlorination catalyst for preparing trifluorochloroethylene and trichloroethylene |
| CN105457651A (en) * | 2014-09-05 | 2016-04-06 | 浙江蓝天环保高科技股份有限公司 | Hydrodechlorination catalyst and application thereof in preparation of chlorotrifluoroethylene |
| KR20180003666A (en) * | 2016-06-30 | 2018-01-10 | 연세대학교 산학협력단 | A semiconductor device and a method of fabricating the same |
| CN109603707A (en) * | 2018-12-26 | 2019-04-12 | 大连海事大学 | A kind of CH4/CO2Low temperature directly synthesizes the device and its synthetic method of C1-C4 alcohol |
| CN111013604A (en) * | 2019-11-21 | 2020-04-17 | 浙江工业大学 | Catalyst for catalytic hydrodechlorination and preparation method and application thereof |
| CN112569996A (en) * | 2020-12-10 | 2021-03-30 | 中化蓝天集团有限公司 | Catalyst for preparing perhalogenated ethylene and preparation method and application thereof |
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