Catalyst as well as preparation method and application thereof

Abstract

The invention provides a catalyst and a preparation method and application thereof, the catalyst comprises a compound with a chemical formula of Ba < 1-x > RexPbO3, x is greater than or equal to 0 and less than or equal to 0.4, and the compound with the chemical formula of Ba < 1-x > RexPbO3 has a perovskite structure. The catalyst disclosed by the invention has the characteristics of stable structure, high strength, high activity and easiness in regeneration, is used for preparing the dimethyl ketene compound by cracking isobutyric anhydride, and has good isobutyric anhydride conversion rate and selectivity of ketene compounds such as dimethyl ketene.

Description

Technical Field

[0001] The present application relates to the technical field of catalysts and organic synthesis, and in particular to a catalyst and a preparation method and application thereof. Background Art

[0002] Vinyl ketone compounds are important intermediates for high-performance organic compounds, such as dimethylvinyl ketone, divinyl ketone and vinyl ketone. Since vinyl ketone compounds are carboxylic acid derivatives containing two consecutive double bonds and are highly unsaturated, the organic compound is unstable and can undergo addition, decomposition and polymerization reactions to synthesize a variety of compounds. This compound is an important monomer for the production of fine chemicals, so it is widely used in bottle flakes, high-end films, molded products, coatings and other fields. At the same time, this type of compound does not contain carcinogens and other toxic substances and can be used in the field of food packaging. Typical vinyl ketone compounds include vinyl ketone, divinyl ketone and dimethylvinyl ketone.

[0003] Patent application with publication number CN 114588889A describes a method for preparing ketene compounds using a catalyst with an aluminum silicate carrier. The Si / Al molar ratio in the aluminum silicate carrier in the catalyst is preferably 0.5-15:1; the active components include SiO2 and any Al2O3 and TiO2 that may or may not be contained; the auxiliary agent is niobium pentoxide; the catalyst surface hydroxyl concentration is 1-150H / nm 2 , preferably 2-110H / nm 2 The catalyst used in this process to prepare ketene compounds contains rare metals, the catalyst cost is high, and the process is complicated.

[0004] The patent with publication number CN 105732354A discloses a method for preparing 2,2,4,4-tetramethyl-1,3-cyclobutanedione, which is to carry out a cracking reaction in a fixed bed cracking reactor under the condition of a volume ratio of isobutyric acid or isobutyric anhydride to inert gas of 1 / 10 to 1 / 5 to prepare dimethyl ketene; then the dimethyl ketene obtained after cracking is directly polymerized in a solution in the same polymerization kettle to obtain 2,2,4,4-tetramethyl-1,3-cyclobutanedione. Under the cracking conditions, the reaction temperature is 440℃~550℃, the reaction pressure is 3KPa~70KPa, and the contact time is 0.01s~1s, but the conversion rate and yield of isobutyric acid and isobutyric anhydride are low during the thermal cracking process, which limits the industrial application of this method.

[0005] The patent with publication number CN 110105186A discloses that the total amount of carrier gas, low-carbon hydrocarbons and carboxylic acid and / or organic anhydride is used as the basis, wherein the content of low-carbon hydrocarbons is preferably 5-15% by weight, the mass ratio of low-carbon hydrocarbons to carboxylic acid and / or organic anhydride is preferably 6-18:100, the cracking temperature is preferably 450°C to 750°C, the partial pressure is preferably 10 to 80KPa, and the material residence time is preferably 0.1 to 1s. The metal catalyst is MgO, ZnO and TiO2; the non-metallic oxide catalyst is SiO2 and / or triethyl phosphate; this method solves the problem of by-products and carbon deposition caused by further cracking of DMK, but this method will introduce other impurities into the product, the cracking product is relatively complex, and the cost required for subsequent separation of the product is high, thereby limiting industrial production.

[0006] In summary, the current preparation methods of dimethyl ketene mainly include isobutyric acid thermal cracking method and isobutyric anhydride thermal cracking method. The isobutyric acid method is used to prepare dimethyl ketene, and the reaction temperature is high, there are many side reactions, and the yield of the product is low; the isobutyric anhydride method is used to prepare dimethyl ketene, and the cost of raw materials is high, and the conversion rate of isobutyric anhydride per pass is low. Therefore, it is necessary to find a catalyst that can reduce the cracking reaction temperature, reduce the occurrence of side reactions during the cracking process, reduce carbon deposition during the reaction process, and increase the yield of ketene compounds, thereby reducing the energy consumption and cost of production and improving the economy of industrial production. Summary of the invention

[0007] In view of this, an object of the present application is to provide a catalyst comprising a barium lead acid compound Ba having a perovskite structure. 1-x Re x PbO3, which has a stable structure, high strength, high activity and easy regeneration, is a catalyst used for the cracking of isobutyric anhydride to prepare dimethyl ketene compounds. It has good isobutyric anhydride conversion rate and selectivity for ketene compounds such as dimethyl ketene.

[0008] Another object of the present application is to provide a method for preparing a catalyst.

[0009] Another object of the present application is to provide a method for preparing ketene compounds.

[0010] To achieve the above object, the first aspect of the present application provides a catalyst comprising a chemical formula of Ba 1-x Re x PbO3 compound, wherein 0≤x≤0.4; the chemical formula is Ba 1-x Re x The compound of PbO3 has a perovskite structure.

[0011] In some embodiments, the value of x is 0.1-0.3.

[0012] The second aspect of the present application provides a method for preparing a catalyst, comprising:

[0013] The precipitant is subjected to a precipitation reaction with a mixed solution containing a barium source and a lead source to obtain a precipitate;

[0014] washing, drying, grinding and then calcining the precipitate to obtain the catalyst;

[0015] The mixed solution contains Pb 2+ and Ba 2+ The molar ratio is 1:(1-x).

[0016] In some embodiments, the mixed solution further includes a rhenium source.

[0017] In some embodiments, the mixed solution contains Pb 2+ and Ba 2+ The molar ratio is (1-2):1.

[0018] In some embodiments, the barium source includes at least one of barium acetate, barium chloride, and barium nitrate.

[0019] In some embodiments, the lead source includes at least one of lead acetate, lead chloride, and lead nitrate.

[0020] In some embodiments, the precipitant is oxalic acid solution.

[0021] In some embodiments, the concentration of the precipitant is 0.4-0.6 mol / L.

[0022] In some embodiments, the precipitant and the Ba 2+ The molar ratio is (1-1.5):1.

[0023] In some embodiments, the rhenium source includes at least one of rhenium nitrate and rhenium chloride.

[0024] In some embodiments, the mixed solution contains Pb 2+ and Ba 2+ The molar ratio is 1:1.

[0025] In some embodiments, the mixed solution has Re 3+ and Pb 2+ The molar ratio is (0.1-1):1, preferably (0.1-0.4):1.

[0026] In some embodiments, the drying temperature is 80-100°C, preferably 90°C.

[0027] In some embodiments, the drying time is 12-24 hours.

[0028] In some embodiments, the calcination temperature is 800-1000°C, preferably 850°C.

[0029] In some embodiments, the calcination time is 1.5-4 hours.

[0030] In some embodiments, the precipitation reaction temperature is 20-40° C., and the precipitation reaction time is 2-5 h.

[0031] In some embodiments, the pH of the precipitate after washing is 5-7.

[0032] In some embodiments, the precipitation reaction is performed on the mixed solution containing the barium source and the lead source by the precipitant, comprising: dropping the precipitant into the mixed solution under stirring to perform the precipitation reaction.

[0033] The third aspect of the present application provides a method for preparing a vinyl ketone compound, comprising:

[0034] Under the action of a catalyst, isobutyric anhydride is subjected to a cracking reaction to obtain the ketene compound;

[0035] The catalyst is the catalyst described in the present application, or the catalyst is a catalyst prepared by the catalyst preparation method described in the present application.

[0036] In some embodiments, the temperature of the cracking reaction is 450-500° C., and the pressure of the cracking reaction is 10-70 KPa.

[0037] In some embodiments, the cleavage reaction is performed under an inert gas atmosphere.

[0038] In some embodiments, the reaction flow rate of the isobutyric anhydride is 0.33-0.65 mL / min.

[0039] In some embodiments, the cleavage reaction is carried out in a fluidized bed reactor or a fixed bed reactor.

[0040] In some embodiments, the ketene compound is dimethyl ketene.

[0041] The catalyst described in this application has at least the following beneficial effects:

[0042] The catalyst includes a barium lead acid compound Ba having a perovskite structure. 1-x Re xPbO3, which has a stable structure, high strength, high activity and easy regeneration, is a catalyst used for the cracking of isobutyric anhydride to prepare dimethyl ketene compounds. It has good isobutyric anhydride conversion rate and selectivity for ketene compounds such as dimethyl ketene.

[0043] Additional aspects and advantages of the present application will be given in part in the description below, and in part will become apparent from the description below, or will be learned through the practice of the present application. DETAILED DESCRIPTION

[0044] The embodiments of the present application are described in detail below. The embodiments are exemplary and intended to be used to explain the present application, but should not be construed as limiting the present application.

[0045] In this application, the disclosure of numerical ranges includes all values ​​within the entire range and the disclosure of further subdivided ranges, including the endpoints and sub-ranges given in these ranges.

[0046] In this application, the raw materials, equipment, etc. involved, unless otherwise specified, are all raw materials and equipment that can be made through commercial channels or known methods; the methods involved, unless otherwise specified, are all conventional methods.

[0047] <Catalyst>

[0048] The catalyst of the embodiment of the present application includes a chemical formula of Ba 1-x Re x A compound of PbO3, wherein 0≤x≤0.4.

[0049] In the embodiments of the present application, 0≤x≤0.4 can increase the catalyst active sites and improve the yield of the target product.

[0050] Exemplarily, the value of x includes but is not limited to 0, 0.05, 0.15, 0.25 or 0.38.

[0051] As a preferred embodiment, the value of x is 0.1-0.3, more preferably 0.15-0.25.

[0052] In some embodiments, the above chemical formula is Ba 1-x Re x The compound of PbO3 has a perovskite structure.

[0053] In the embodiments of the present application, the above chemical formula is Ba 1-x Re x In the compound of PbO3, the valence of Pb is +4, the valence of Ba is +2, and the valence of Re is +2.

[0054] The catalyst of the embodiment of the present application includes a barium lead acid compound Ba having a perovskite structure. 1-x Re x PbO3, which has a stable structure, high strength, high activity and easy regeneration, is a catalyst used for the cracking of isobutyric anhydride to prepare dimethyl ketene compounds. It has good isobutyric anhydride conversion rate and selectivity for ketene compounds such as dimethyl ketene.

[0055] <Method for preparing catalyst>

[0056] The preparation method of the catalyst of the embodiment of the present application is a co-precipitation method, which can be used to prepare the catalyst of the embodiment of the present application.

[0057] The method for preparing the catalyst of the embodiment of the present application comprises the following steps:

[0058] S101, a precipitant is subjected to a precipitation reaction with a mixed solution containing a barium source and a lead source to obtain a precipitate; Pb in the mixed solution 2+ and Ba 2+ The molar ratio is 1:(1-x), 0≤x≤0.4.

[0059] In the embodiment of the present application, Pb in the mixed solution 2+ and Ba 2+ The molar ratio of Pb is within the above range, which can form a stable A-site doped perovskite structure; 2+ and Ba 2+ If the molar ratio of is too low (for example, less than 1:1), there is too little B-site element to form a perovskite structure.

[0060] In some embodiments, the barium source includes but is not limited to at least one of barium acetate (Ba(CH3COO)2), BaCl2, Ba(NO3)2, etc., preferably barium acetate.

[0061] In some embodiments, the lead source includes but is not limited to at least one of lead acetate (Pb(CH3COO)2), etc., preferably lead acetate.

[0062] In some embodiments, the precipitating agent is oxalic acid solution.

[0063] In some embodiments, the concentration of the precipitant is 0.4-0.6 mol / L, including but not limited to 0.4 mol / L, 0.5 mol / L or 0.6 mol / L, etc., preferably 0.5 mol / L.

[0064] In the examples of the present application, the lower the concentration of the precipitant, the finer the particles of the prepared catalyst powder.

[0065] In some embodiments, the precipitant and Ba 2+The molar ratio is (1-1.5):1, including but not limited to 1:1, 1.2:1, 1.25:1, 1.35:1 or 1.5:1, etc.

[0066] In some embodiments, the mixed solution contains Pb 2+ and Ba 2+ The molar ratio is (1-2):1, including but not limited to 1:1, 1.25:1, 1.35:1, 1.5:1, 1.55:1, 1.6:1, 1.67:1, 1.7:1, 1.8:1, 1.9:1 or 2:1, etc.

[0067] As a preferred example, the mixed solution contains Pb 2+ and Ba 2+ The molar ratio is 1:1.

[0068] In some embodiments, the mixed solution further includes a rhenium source.

[0069] In some embodiments, the rhenium source includes but is not limited to at least one of rhenium nitrate (Re(NO3)3), rhenium chloride (ReCl3), etc., preferably rhenium nitrate.

[0070] In some embodiments, Re in the mixed solution 3+ and Pb 2+ The molar ratio is (0-0.4):1, including but not limited to 0.1:1, 0.2:1, 0.3:1, 0.4:1, etc., preferably (0.1-0.2):1.

[0071] It should be noted that Re in the mixed solution in this application 3+ and Pb 2+ The molar ratio is (0-0.4):1. When it is 0:1, it means there is no Re 3+ .

[0072] In the embodiment of the present application, Re in the mixed solution 3+ and Pb 2+ When the molar ratio is within the above range, a stable A-site doped perovskite structure can be formed; when it is higher than 0.4:1, the A-site doping amount is too much and a stable perovskite structure cannot be formed.

[0073] In some embodiments, the temperature of the precipitation reaction is 20-40°C, including but not limited to 20°C, 25°C, 30°C, 35°C or 40°C, etc.

[0074] In some embodiments, the precipitation reaction time is 2-5 hours, including but not limited to 2 hours, 3 hours, 4 hours, 4.5 hours or 5 hours.

[0075] In some embodiments, the precipitation reaction is performed on the mixed solution containing the barium source and the lead source by the precipitant, comprising: dropping the precipitant into the mixed solution under stirring to perform the precipitation reaction.

[0076] As a preferred example, the precipitant is slowly dropped into the mixed solution to perform a precipitation reaction.

[0077] Exemplarily, the precipitant is dripped into the mixed solution to perform precipitation reaction at a rate of 2-5 mL / S.

[0078] In some embodiments, the method for preparing the catalyst of the embodiment of the present application further comprises:

[0079] Test with an alkaline substance to make sure the solution is fully reacted.

[0080] In the embodiment of the present application, an alkaline substance is added to the reaction system. If the alkaline substance is 2+ 、Re 3+ , Pb 2+ The absence of precipitation of these metal elements proves that the reaction is complete.

[0081] Illustratively, the alkaline substance includes, but is not limited to, NaOH, KOH, and the like.

[0082] S102, washing, drying, grinding and then calcining the precipitate to obtain a catalyst.

[0083] In some embodiments, the detergent used for washing includes but is not limited to distilled water, purified water, etc.

[0084] In some embodiments, washing can be performed multiple times until the pH of the precipitate is 5-7.

[0085] Illustratively, the pH of the precipitated product after washing includes, but is not limited to, 5, 5.5, 6, 6.5 or 7, etc.

[0086] As a preferred example, the drying temperature is 90°C.

[0087] In some embodiments, the drying method includes but is not limited to drying, spray drying, reduced pressure drying, etc.

[0088] In some embodiments, the calcination temperature is 800-1000°C, including but not limited to 800°C, 850°C, 900°C, 950°C, 1000°C, etc. When the calcination temperature is within the above range, a relatively stable perovskite material with uniform particle size can be formed; when the calcination temperature is lower than 800°C, the perovskite material cannot be formed; when the calcination temperature is higher than 1000°C, the particles are relatively agglomerated and the specific surface area is significantly reduced.

[0089] As a preferred example, the calcination temperature is 850°C.

[0090] In some embodiments, the calcination time is 1.5-4 h, including but not limited to 1.5 h, 2 h, 2.5 h, 3 h, 3.5 h or 4 h.

[0091] As a preferred example, the calcination time is 2 hours.

[0092] In some embodiments, calcination is performed in an air atmosphere.

[0093] The preparation method of the catalyst of the embodiment of the present application, in addition to the beneficial effects of the catalyst of the embodiment of the present application, can also bring at least the following beneficial effects:

[0094] The preparation method is simple, pollution-free, and easily recyclable, and is a green and environmentally friendly process. It also has the advantages of a short catalyst preparation period and less consumption of manpower and material resources.

[0095] <Method for preparing vinyl ketone compounds>

[0096] The method for preparing ketene compounds of the embodiment of the present application comprises: subjecting isobutyric anhydride to a cracking reaction under the action of a catalyst to obtain ketene compounds; wherein the catalyst is the catalyst of the embodiment of the present application, or the catalyst is a catalyst prepared by the method for preparing the catalyst of the embodiment of the present application.

[0097] In some embodiments, the temperature of the cracking reaction is 450-500°C, including but not limited to 450°C, 460°C, 470°C, 480°C, 490°C or 500°C, etc.

[0098] In some embodiments, the pressure of the cracking reaction is 10-70 KPa, including but not limited to 10 KPa, 20 KPa, 30 KPa, 40 KPa, 50 KPa, 60 KPa or 70 KPa, etc.

[0099] In some embodiments, the cleavage reaction is performed under an inert gas atmosphere.

[0100] Exemplarily, the inert gas includes, but is not limited to, at least one of nitrogen, argon, helium, and the like.

[0101] In some embodiments, the reaction flow rate of isobutyric anhydride is 0.33-0.65 mL / min, including but not limited to 0.33 mL / min, 0.4 mL / min, 0.5 mL / min, 0.6 mL / min or 0.65 mL / min, etc.

[0102] In some embodiments, the cleavage reaction is carried out in a fluidized bed reactor or a fixed bed reactor, preferably in a fixed bed reactor.

[0103] In some embodiments, the inert gas and the isobutyric anhydride raw material vapor are separately fed into a fluidized bed reactor or a fixed bed reactor filled with a catalyst.

[0104] In some embodiments, the method for preparing the ketene compound further comprises: cooling the reaction liquid through a shell-and-tube heat exchanger or a cooling circulation pump after the cracking reaction, and obtaining the ketene compound product after gas-liquid separation.

[0105] As a preferred example, after the cracking reaction, the reaction solution is cooled by a cooling circulation pump.

[0106] In the embodiments of the present application, a conventional gas-liquid separation tank having a gas-liquid separation function can be used for gas-liquid separation.

[0107] In some embodiments, the ketene compounds include but are not limited to at least one of dimethyl ketene, ketene, diketene, and the like.

[0108] Certain features of the present technology are further illustrated in the following non-limiting examples.

[0109] 1. Main raw material sources and performance testing methods

[0110] 1. Main sources of raw materials

[0111] Rhenium nitrate hexahydrate, AR, Sinopharm Chemical Reagent Co., Ltd.;

[0112] Barium acetate, AR, Beijing Yikainuo Technology Co., Ltd.;

[0113] Lead acetate trihydrate, AR, Beijing Myrida Technology Co., Ltd.;

[0114] Anhydrous oxalic acid, AR, Sinopharm Chemical Reagent Co., Ltd.;

[0115] Other raw materials, unless otherwise specified, are commercially available.

[0116] 2. Performance testing methods

[0117] The calculation method of the relevant indicators of the catalyst used for cracking reaction is:

[0118] Conversion rate of raw materials = molar amount of converted isobutyric anhydride / molar amount of total isobutyric anhydride input * 100%

[0119] Product selectivity = mole number of ketene compounds obtained / mole number of converted isobutyric anhydride * 100%

[0120] 2. Examples and Comparative Examples

[0121] 1. Catalyst preparation

[0122] Example 1

[0123] The catalyst in this example is Ba 0.9 Re 0.1 The preparation method of PbO3 powder comprises the following steps:

[0124] 1) Weigh 2.9884gBa(CH3COO)2, 4.9308gPb(CH3C00)2·3H2O and 0.4239gRe(NO3)3·6H20(Ba 2+ and Pb 2+ Molar ratio 0.9:1, Re 3+ The amount of substance is Pb 2+ 10% of the amount of the substance), add them into a beaker filled with 100mL of distilled water respectively, and stir continuously to make them fully dissolved to obtain Ba(CH3COO)2 solution, Pb(CH3COO)2 solution and Re(NO3)3 solution.

[0125] 2) Mix the Ba(CH3COO)2 solution, Pb(CH3COO)2 solution and Re(NO3)3 solution obtained in step 1) to obtain a mixed solution.

[0126] 3) 40 mL of 0.5 mol / L oxalic acid solution was slowly dripped into the mixed solution obtained in step (2) at a rate of 1 mL / min, and the solution was continuously stirred to allow the solution to precipitate fully until it was completely precipitated. The solution was tested with a 1 mol / L NaOH solution to determine that the solution was completely reacted to obtain a precipitate.

[0127] The method of using 1 mol / L NaOH solution to test and confirm the complete reaction of the solution is: add 1 mol / L NaOH solution dropwise to the reaction system, and no precipitation is generated (NaOH and Ba 2+ 、Re 3+ , Pb 2+ These metal elements do not form precipitates), proving that the solution is completely reacted.

[0128] 4) The precipitate obtained in step (3) was repeatedly washed with distilled water until the pH value of the precipitate reached 6.5, thereby obtaining a washed precipitate (oxalate precipitate).

[0129] 5) The washed precipitate obtained in step 4) is placed in a drying oven at 90° C. for 12 h to obtain a dry powder.

[0130] 6) Grind the dry powder obtained in step 5) in a mortar and shake well in a wide-mouth bottle to obtain dry oxalate powder.

[0131] 7) The dried oxalate powder obtained in step 6) was calcined in a tubular furnace at 850° C. for 2 h in an air atmosphere to obtain the catalyst of this example.

[0132] Example 2

[0133] This embodiment is basically the same as Embodiment 1, except that:

[0134] The catalyst in this example is Ba 0.8 Re 0.2 PbO3 powder, wherein the preparation method thereof:

[0135] In step 1), 2.6564 g Ba(CH3COO)2, 4.9308 g Pb(CH3C00)2·3H2O and 0.8479 g Re(NO3)3·6H20(Ba 2+ and Pb 2+ Molar ratio 0.8:1, Re 3+ The amount of substance is Pb 2+ 20% of the amount of substance).

[0136] Example 3

[0137] This embodiment is basically the same as Embodiment 1, except that:

[0138] The catalyst in this example is Ba 0.7 Re 0.3 PbO3 powder, wherein the preparation method thereof:

[0139] In step 1), 2.3243 g Ba(CH3COO)2, 4.9308 g Pb(CH3C00)2·3H2O and 1.2718 g Re(NO3)3·6H20(Ba 2+ and Pb 2+ Molar ratio 0.7:1, Re 3+ The amount of substance is Pb 2+ 30% of the amount of substance).

[0140] Example 4

[0141] This embodiment is basically the same as Embodiment 1, except that:

[0142] The catalyst in this example is Ba 0.6 Re 0.4 PbO3 powder, wherein the preparation method thereof:

[0143] In step 1), 1.9923 g Ba(CH3COO)2, 4.9308 g Pb(CH3C00)2·3H2O and 1.6957 g Re(NO3)3·6H20(Ba2+ and Pb 2+ Molar ratio 1:1, Re 3+ The amount of substance is Pb 2+ 40% of the amount of substance).

[0144] Example 5

[0145] This embodiment is basically the same as Embodiment 1, except that:

[0146] The catalyst of this embodiment is BaPbO3 powder, and its preparation method is as follows:

[0147] Step 1) is: weigh 3.3205gBa(CH3COO)2 and 4.9308gPb(CH3C00)2·3H2O(Ba 2+ and Pb 2+ Molar ratio 1:1), add them into a beaker filled with 100mL of distilled water respectively, and stir continuously to make them fully dissolved to obtain Ba(CH3COO)2 solution and Pb(CH3COO)2 solution.

[0148] Step 2) is: mix the Ba(CH3COO)2 solution and the Pb(CH3COO)2 solution obtained in step 1) to obtain a mixed solution.

[0149] Example 6

[0150] This embodiment is basically the same as Embodiment 1, except that:

[0151] In step 7, the dried oxalate powder obtained in step 6) is calcined in a tube furnace at 800° C. for 2 h in an air atmosphere.

[0152] Example 7

[0153] This embodiment is basically the same as Embodiment 1, except that:

[0154] In step 7, the dried oxalate powder obtained in step 6) is calcined in a tube furnace at 1000° C. for 2 h in an air atmosphere.

[0155] Example 8

[0156] This embodiment is basically the same as Embodiment 1, except that:

[0157] In step 7), the dried oxalate powder obtained in step 6) is calcined in a tube furnace at 900° C. for 2 h.

[0158] Example 9

[0159] This embodiment is basically the same as Embodiment 1, except that:

[0160] In step 5), the washed precipitate obtained in step 4) is placed in a drying oven at 80° C. for 20 hours.

[0161] Example 10

[0162] This embodiment is basically the same as Embodiment 1, except that:

[0163] In step 5), the washed precipitate obtained in step 4) is placed in a drying oven at 100° C. for 18 hours.

[0164] 2. Preparation of ketene compounds

[0165] Application Example 1

[0166] 3g of the catalyst prepared in Example 1 was placed in a fluidized bed reactor with an inner diameter of 15mm, an outer diameter of 25mm, and a length of 800mm (effective length of 600mm). During the experiment, the flow rate of the carrier gas nitrogen was 150mL / min. At the same time, the raw material isobutyric anhydride (ANIB) and the internal standard p-xylene were fully mixed at a volume ratio of 3:1 and then entered the preheater (temperature of 200°C) at 0.33mL / min, 0.5mL / min, and 0.65mL / min to vaporize it. After vaporization, it entered the fluidized bed reactor for cracking reaction. The conversion rate of the raw material isobutyric anhydride (ANIB) and the selectivity of dimethyl ketone (DMK) under the reaction temperatures of 450°C, 475°C, and 500°C and the reaction pressure of 20KPa are shown in Table 1.

[0167] Table 1 Cracking results under different process conditions in Application Example 1

[0168] Technology Flow rate / mL / min Reaction temperature / ℃ Reaction pressure / KPa ANIB conversion rate / % DMK Selectivity 1 0.33 450 20 36.0 31.7 2 0.33 475 20 41.9 38.8 3 0.33 500 20 45.5 43.0 4 0.50 450 20 35.2 28.9 5 0.50 475 20 31.4 37.6 6 0.50 500 20 41.9 38.8 7 0.65 450 20 28.8 35.3 8 0.65 475 20 34.0 38.1 9 0.65 500 20 35.6 36.8

[0169] Application Example 2

[0170] 3g of catalyst prepared in Example 2 was placed in a fluidized bed reactor with an inner diameter of 15mm, an outer diameter of 25mm, and a length of 800mm (effective length of 600mm). During the experiment, the flow rate of carrier gas nitrogen was 150mL / min. At the same time, the raw material isobutyric anhydride (ANIB) and the internal standard p-xylene were fully mixed at a volume ratio of 3:1 and then entered the preheater (temperature of 200°C) at 0.33mL / min, 0.5mL / min, and 0.65mL / min to vaporize it. After vaporization, it entered the fluidized bed reactor for cracking reaction. The conversion rate of the raw material isobutyric anhydride (ANIB) and the selectivity of dimethyl ethylene ketone (DMK) under the reaction temperatures of 450°C, 475°C, and 500°C and the reaction pressure of 10KPa are shown in Table 2.

[0171] Table 2 Cracking results under different process conditions in Application Example 2

[0172] Technology Flow rate / mL / min Reaction temperature / ℃ Reaction pressure / KPa ANIB conversion rate / % DMK Selectivity 1 0.33 450 10 39.6 34.3 2 0.33 475 10 44.0 34.5 3 0.33 500 10 46.4 53.5 4 0.50 450 10 41.7 39.5 5 0.50 475 10 43.2 41.5 6 0.50 500 10 43.7 36.4 7 0.65 450 10 36.9 42.0 8 0.65 475 10 41.2 38.5 9 0.65 500 10 42.8 36.0

[0173] Application Example 3

[0174] 3g of catalyst prepared in Example 3 was placed in a fluidized bed reactor with an inner diameter of 15mm, an outer diameter of 25mm, and a length of 800mm (effective length of 600mm). During the experiment, the flow rate of carrier gas nitrogen was 150mL / min. At the same time, the raw material isobutyric anhydride (ANIB) and the internal standard p-xylene were fully mixed at a volume ratio of 3:1 and then entered the preheater (temperature of 200°C) at 0.33mL / min, 0.5mL / min, and 0.65mL / min to vaporize it. After vaporization, it entered the fluidized bed reactor for cracking reaction. The conversion rate of the raw material isobutyric anhydride (ANIB) and the selectivity of dimethyl ethylene ketone (DMK) under the reaction temperatures of 450°C, 475°C, and 500°C and the reaction pressure of 20KPa are shown in Table 3.

[0175] Table 3 Cracking results under different process conditions in Application Example 3

[0176] Technology Flow rate / mL / min Reaction temperature / ℃ Reaction pressure / KPa ANIB conversion rate / % DMK Selectivity 1 0.33 450 20 46.1 41.3 2 0.33 475 20 48.9 42.2 3 0.33 500 20 51.4 48.5 4 0.50 450 20 43.0 52.8 5 0.50 475 20 48.3 46.5 6 0.50 500 20 50.5 45.7 7 0.65 450 20 50.2 39.5 8 0.65 475 20 48.7 43.2 9 0.65 500 20 49.0 46.8

[0177] Application Example 4

[0178] 3g of catalyst prepared in Example 4 was placed in a fluidized bed reactor with an inner diameter of 15mm, an outer diameter of 25mm, and a length of 800mm (effective length of 600mm). During the experiment, the flow rate of carrier gas nitrogen was 150mL / min. At the same time, the raw material isobutyric anhydride (ANIB) and the internal standard p-xylene were fully mixed at a volume ratio of 3:1 and then entered the preheater (temperature of 200°C) at 0.33mL / min, 0.5mL / min, and 0.65mL / min to vaporize it. After vaporization, it entered the fluidized bed reactor for cracking reaction. The conversion rate of the raw material isobutyric anhydride (ANIB) and the selectivity of dimethyl ethylene ketone (DMK) under the reaction temperatures of 450°C, 475°C, and 500°C and the reaction pressure of 30KPa are shown in Table 4.

[0179] Table 4 Cracking results under different process conditions in Application Example 4

[0180] Technology Flow rate / mL / min Reaction temperature / ℃ Reaction pressure / KPa ANIB conversion rate / % DMK Selectivity 1 0.33 450 30 70.9 68.9 2 0.33 475 30 72.6 73.9 3 0.33 500 30 75.9 76.9 4 0.50 450 30 66.2 61.8 5 0.50 475 30 67.7 66.0 6 0.50 500 30 76.9 58.3 7 0.65 450 30 61.8 59.2 8 0.65 475 30 57.8 54.6 9 0.65 500 30 66.3 64.9

[0181] Comparative application example 1

[0182] No catalyst was added to the fluidized bed reactor with an inner diameter of 15 mm, an outer diameter of 25 mm, and a length of 800 mm (effective length of 600 mm). During the experiment, the flow rate of carrier gas nitrogen was 150 mL / min. At the same time, the raw material isobutyric anhydride (ANIB) and the internal standard p-xylene were fully mixed at a volume ratio of 3:1 and then entered the preheater (temperature of 200°C) at 0.33 mL / min, 0.5 mL / min, and 0.65 mL / min to vaporize them. After vaporization, they entered the fluidized bed reactor for cracking reaction. The conversion rate of the raw material isobutyric anhydride (ANIB) and the selectivity of dimethyl ethylene ketone (DMK) under the reaction temperatures of 450°C, 475°C, and 500°C and the reaction pressure of 20 KPa are shown in Table 5.

[0183] Table 5 Comparative cracking results under different process conditions in Application Example 1

[0184] Technology Flow rate / mL / min Reaction temperature / ℃ Reaction pressure / KPa ANIB conversion rate / % DMK Selectivity 1 0.33 450 20 34.7 20.3 2 0.33 475 20 35.5 26.6 3 0.33 500 20 38.3 26.9 4 0.50 450 20 26.9 18.8 5 0.50 475 20 31.2 20.4 6 0.50 500 20 33.3 19.8 7 0.65 450 20 26.9 17.4 8 0.65 475 20 27.7 18.8 9 0.65 500 20 29.3 23.9

[0185] According to Table 1-5:

[0186] (1) It can be seen from Application Example 1 that the higher the temperature and the smallest flow rate, the higher the catalyst conversion rate and selectivity in the thermal cracking reaction than the lower the temperature and the larger the flow rate.

[0187] (2) By comparing Application Examples 1, 2, 3 and 4, it can be seen that the Re 3+ The higher the concentration, the more active the catalyst is, and the higher the conversion and selectivity for the cleavage of isobutyric anhydride (ANIB) are.

[0188] (3) By comparing Application Example 1, Application Example 2, Application Example 3, Application Example 4 and Application Comparative Example 1, it can be seen that the conversion rate and selectivity of the thermal cracking reaction without adding a catalyst are significantly lower than the conversion rate and selectivity of the catalyst in Application Example 1, Application Example 2, Application Example 3, and Application Example 4.

[0189] (4) Comparing the results of the application examples and comparative application examples under different reaction conditions, it can be seen that high concentrations of Re 3+ In the isobutyric anhydride cracking reaction, the catalyst has a high conversion rate of isobutyric anhydride and a high selectivity for dimethyl ketene, which is beneficial to obtaining more target products of ketene compounds.

[0190] In the present application, the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. mean that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the described specific features, structures, materials or characteristics may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0191] Although the embodiments of the present application have been shown and described above, it can be understood that the above embodiments are exemplary and cannot be understood as limitations on the present application. Ordinary technicians in this field can change, modify, replace and modify the above embodiments within the scope of the present application.

Claims

1. A catalyst, characterized in that The catalyst comprises a chemical formula of Ba 1-x Re x PbO3 compound, wherein 0≤x≤0.4; the chemical formula is Ba 1-x Re x The compound of PbO3 has a perovskite structure.

2. The catalyst according to claim 1, characterized in that The value of x is 0.1-0.

3.

3. A method for preparing the catalyst according to claim 1 or 2, characterized in that: include: The precipitant is subjected to a precipitation reaction with a mixed solution containing a barium source and a lead source to obtain a precipitate; washing, drying, grinding and then calcining the precipitate to obtain the catalyst; The mixed solution contains Pb 2+ and Ba 2+ The molar ratio is 1:(1-x).

4. The preparation method according to claim 3, characterized in that: The mixed solution also includes a rhenium source; and / or, The mixed solution contains Pb 2+ and Ba 2+ The molar ratio is (1-2): 1; and / or, The barium source includes at least one of barium acetate, barium chloride and barium nitrate; and / or, The lead source includes at least one of lead acetate, lead chloride and lead nitrate; and / or, The precipitant is oxalic acid solution, The concentration of the precipitant is 0.4-0.6 mol / L; and / or, The precipitant and the Ba 2+ The molar ratio is (1-1.5):

1.

5. The preparation method according to claim 4, characterized in that: The rhenium source includes at least one of rhenium nitrate and rhenium chloride; and / or, The mixed solution contains Pb 2+ and Ba 2+ The molar ratio is 1:1; and / or, The mixed solution contains Re 3+ and Pb 2+ The molar ratio is (0.1-1):1, preferably (0.1-0.4):

1.

6. The preparation method according to claim 3, characterized in that: The drying temperature is 80-100°C, preferably 90°C; and / or, The drying time is 12-24 hours; and / or, The calcination temperature is 800-1000°C, preferably 850°C; and / or, The calcination time is 1.5-4h.

7. The preparation method according to claim 3, characterized in that: The temperature of the precipitation reaction is 20-40° C., and the time of the precipitation reaction is 2-5 hours; and / or, The pH of the precipitate after washing is 5-7; and / or, The precipitant is subjected to a precipitation reaction with a mixed solution containing a barium source and a lead source, comprising: Under stirring conditions, a precipitant is dropped into the mixed solution to carry out a precipitation reaction.

8. A method for preparing ketene compounds, characterized in that: include: Under the action of a catalyst, isobutyric anhydride is subjected to a cracking reaction to obtain the ketene compound; The catalyst is the catalyst according to claim 1 or 2 or a catalyst prepared by the preparation method according to any one of claims 3 to 7.

9. The preparation method according to claim 8, characterized in that: The temperature of the cracking reaction is 450-500°C, and the absolute pressure of the cracking reaction is 10-70KPa; and / or, The cleavage reaction is carried out under an inert gas atmosphere; and / or, The reaction flow rate of the isobutyric anhydride is 0.33-0.65 mL / min; and / or, The cracking reaction is carried out in a fluidized bed reactor or a fixed bed reactor.

10. The preparation method according to claim 8, characterized in that: The ketene compounds mainly refer to dimethyl ketene.