CN107930657B

CN107930657B - Cobalt-based catalyst for synthesizing methyl isobutyl ketone from acetone

Info

Publication number: CN107930657B
Application number: CN201610894439.2A
Authority: CN
Inventors: 唐国旗; 田保亮; 杨溢; 李宝芹
Original assignee: Sinopec Beijing Research Institute of Chemical Industry; China Petroleum and Chemical Corp
Current assignee: Sinopec Beijing Research Institute of Chemical Industry; China Petroleum and Chemical Corp
Priority date: 2016-10-13
Filing date: 2016-10-13
Publication date: 2020-09-15
Anticipated expiration: 2036-10-13
Also published as: CN107930657A

Abstract

The invention discloses a catalyst, belonging to the technical field of application and development of acetone downstream products, which takes cobalt and tin as main active components, takes fluorine as an auxiliary component, selects alumina, silicon oxide or an alumina-silicon oxide composite carrier with rich acid and alkali to promote reaction, is used under mild reaction conditions, adopts an acetone one-step synthesis process, has the product methyl isobutyl ketone yield higher than that of a palladium/resin catalyst used in the existing industrial device, and simultaneously produces a large amount of isopropanol as a byproduct. The catalyst of the invention shows ideal stability, the cost is obviously lower than that of the existing palladium catalyst, and the catalyst has better economic benefit.

Description

Cobalt-based catalyst for synthesizing methyl isobutyl ketone from acetone

Technical Field

The invention relates to a catalyst for ketone condensation, in particular to a catalyst for synthesizing methyl isobutyl ketone by using acetone as a raw material through a one-step method.

Background

Methyl isobutyl ketone (MIBK for short in english) is an important solvent and chemical intermediate, is of great interest due to its excellent performance, has aromatic ketone smell, is colorless and transparent, has a medium boiling point, has very strong dissolving power, can be mixed and dissolved with numerous organic solvents such as alcohol, benzene, diethyl ether and the like, can be used as raw materials of coating, ethyl cellulose, nitrocellulose, audio-video tape, paraffin, various natural or synthetic resin solvents, dewaxing agents, rare earth metal extracting agents, polymerization reaction initiating agents, surfactants, medicines, pesticide extracting agents and rubber anti-aging agents, is a current rather delicate fine petrochemical intermediate, has irreplaceability in many application fields, and is still imported annually in China.

As seen in the current market, methyl isobutyl ketone is produced mainly using acetone as a raw material. The method is divided into a three-step method and a one-step method according to the reaction process. The one-step method has the advantages of short process flow, low investment, high raw material conversion rate and the like, and becomes a main synthesis process route.

The process for producing methyl isobutyl ketone by using the acetone three-step method illustrates the reaction process of synthesizing methyl isobutyl ketone by using acetone: condensation, acid-catalyzed dehydration and selective hydrogenation. With the continuous development and progress of catalytic technology, people begin to research multifunctional catalysts integrating the three processes. The German Veba-Chemie company led to the construction of a one-step production plant in 1968, with a single-pass conversion of acetone of 34.4% and a selectivity for MIBK of 96.5%. The preparation of the catalyst is difficult by selecting strong acid cation exchange resin and Pd with hydrogenation function on double bonds of olefin as the catalyst by two companies, namely Veba and Taxaco in Germany. In recent years, Mobil corporation in the United states developed a Pd-NSM-5 modified zeolite catalyst which can be prepared by impregnation and calcination. In recent years, China also starts to research and develop multifunctional catalysts, such as industrial Pd/resin catalysts and molecular sieve catalysts, ZSM-5 molecular sieves synthesized by an amine-free method are used as carriers, metal Pd is used as an active component, and metal cobalt is used as a promoter component to synthesize methyl isobutyl ketone. And the Liu self-strength and the like adopt an impregnation method to prepare the BaO/alumina catalyst. The Lihongxia takes HZSM-5 molecular sieve as carrier, loads multi-metal active components such as Pd, Cu, Zn, Ni and the like, and has the reaction temperature of 160 ℃ and the reaction pressure of 18Kg/cm²The conversion of acetone was 42.7% and the selectivity of MIBK was as high as 95.6% under the liquid phase reaction conditions of (1), but it was not industrialized. Preparation of Cu-MgO-Al by precipitation method₂O₃The catalyst has acetone conversion of 71.7% and MIBK selectivity of 51%, and the literature gives no catalyst life.

In addition, diisobutyl ketone (DIBK) is a high-boiling-point solvent and an organic synthetic intermediate with excellent performance, has the advantages of high boiling point, good compatibility and the like, is widely applied to the industries of vacuum plating, leather coating, medicine, plastic paint, mineral processing, chemical engineering and the like, can be used as a solvent of paint, food refining, vinyl resin coating and other synthetic resin coatings, can be used as an extractant of rare earth metal, can be used as a dispersing agent to produce organic aerosol, and can be used as an intermediate for producing medicine and pesticide. In recent years, the demand of diisobutyl ketone is continuously increased, the market prospect is very optimistic, and the price is high.

4-methyl-2-pentanol, commonly called as methyl isobutyl carbinol (MIBC for short), is an excellent medium-boiling point solvent, is mainly used as a solvent for dyes, petroleum, rubber, resin, paraffin, nitrocellulose, ethyl cellulose and the like, is used as an inert solvent for nitrocellulose lacquer, can increase the luster and the smoothness of paint, improves the reddening property, is used as a solvent in the manufacture of lubricating oil additives and the like. Raw materials for organic synthesis, mineral flotation detergents, such as for example extracted silicon and copper sulphate ores, and brake fluids. In recent years, the demand of 4-methyl-2-pentanol is continuously increased, the market prospect is very optimistic, and the price is high.

With the continuous construction of domestic MIBK devices, the devices for simply producing MIBK do not have the profitability, and most devices are in a production stop or low-load operation state. Industry has begun to look for downstream products of MIBK to improve the profitability and risk resistance of the device, and one important product is MIBC, which is also expensive and has a good market value. Based on this market demand, the inventors developed the catalyst of the present invention.

Throughout the literature and reports, the catalyst currently in commercial use is still a Pd/resin catalyst, the catalyst life is 9-12 months, and the catalyst cannot produce or by-produce 4-methyl-2-pentanol (MIBC). Other catalysts have not been reported industrially. The inventors have intensively studied and found that a critical factor for the stability of the catalyst is a condensate produced by condensation of acetone, and the resulting MIBK undergoes further condensation reaction to produce a larger condensate. These condensates coat the catalyst surface, causing deactivation of the catalytically active sites.

Disclosure of Invention

The palladium catalyst used in industry in the prior art has short service life and high cost, while the widely researched non-noble metal catalyst still can not meet the industrialization requirement, the inventor carries out deep and detailed research on the non-metal catalyst according to the enterprise requirement, and obtains more ideal catalyst and process technology through years of experimental research.

The specific technical scheme of the invention is as follows:

the invention provides a cobalt-based catalyst for synthesizing methyl isobutyl ketone by using acetone as a raw material through a one-step method, which comprises a carrier and load components of cobalt, tin and fluorine, wherein 20-50% of tin in atomic percentage exists in a metal state, and the rest of tin exists in an oxidation state.

The inventor screens out a catalyst with better performance through a large number of tests, and the catalyst comprises the following components by mass percent of 100 percent:

(1) the cobalt accounts for 5 to 12 percent of the metal state by mass percent;

(2) the tin, the metallic tin and the oxidized tin are calculated by being converted into the metallic tin, and the mass percentage content is 6-22%;

(3) fluorine, calculated by being converted into simple substance fluorine, the mass percent content is 0.05-0.8%;

(4) a carrier, the balance excluding the supported component.

The catalyst prepared by the invention needs to be subjected to reduction treatment before use, most of cobalt is reduced to be in a metal state, but some components such as fluorine cannot be reduced, and tin is not completely reduced to be in the metal state.

In order to better disperse the supported component, the catalyst of the present invention uses a support, for example, alumina, silica, an alumina-silica composite support, or a molecular sieve. From the point of view of the condensation, dehydration and hydrogenation processes undergone by acetone, said alumina is more preferably an acid-modified alumina or a base-modified alumina, both of which promote the condensation and dehydration processes. Alternatively, acid-modified silica or alkali-modified silica may be used as the silica. The use of an alumina-silica composite support is more advantageous from the viewpoint of structural stability of the support, and of course, an acid-modified alumina-silica composite support or an alkali-modified alumina-silica composite support is more preferable. The so-called acid modification may be carried out by using phosphoric acid, sulfuric acid, hydrofluoric acid or boric acid at the time of molding the support. The alkali modification may be carried out by adding a basic metal salt such as lanthanum nitrate, an alkali metal salt, an alkaline earth metal salt or the like to the support during the molding thereof.

The source of cobalt metal in the catalyst can be selected from water-soluble metal salts such as nitrate, sulfate, chloride, acetate, oxalate and bromide, or from metal cobalt, such as cobalt metal plate, etc. More specifically, the water-soluble metal salt is selected from one or more of cobalt nitrate, cobalt chloride, cobalt oxalate, cobalt sulfate and cobalt acetate, and more preferably from one or more of cobalt nitrate, cobalt acetate and cobalt oxalate.

Tin is another important component in the catalyst, and the addition of a proper amount of tin greatly improves the activity, selectivity and stability of the catalyst.

After the addition of the auxiliary agent tin, the indexes of the catalyst such as activity, stability and the like representing the reaction performance of the catalyst are greatly improved, wherein the reasons can be various: tin improves the electronic morphology of cobalt. More surprisingly, the inventor finds that the effect of improving the reaction performance of the catalyst by the aid of tin is more obvious in the cobalt-based catalyst prepared by coprecipitation, deposition-precipitation, ammonia evaporation precipitation, sol-gel and suction filtration and ball milling after being dissolved into alloy.

The source of tin is not limited and may be any known tin-containing compound. Further preferable tin sources include metallic tin particles, tin dioxide, tin disulfide, stannous oxide, metastannic acid, stannous pyrophosphate, stannic chloride, stannous chloride, stannic acetate, stannous oxalate, stannous octoate, stannous fluoroborate, stannic bromide, stannic fluoride, stannous sulfate, stannic arsenate, stannous fluoroborate, sodium stannate, potassium stannate, stannic acid ammonium, dibutyltin, tributyltin, tetrabutyltin, tetraphenyltin, triphenyltin acetate, dibutyltin maleate, stannic methanesulfonate, stannic ethanesulfonate, stannic propanesulfonate, stannic 2-hydroxyethyl-1-sulfonate, stannic 2-hydroxybutyl-1-sulfonate and the like.

Fluorine is an important nonmetal auxiliary agent in the catalyst, and the overall acidity and alkalinity of the catalyst can be adjusted by adding a proper amount of fluorine element, so that the selectivity and the stability of the catalyst are improved. The source of fluorine is not limited and may be any known fluorine-containing compound.

The adding mode of the fluorine element can be selected from any one of the following modes: adding after dissolving together with cobalt salt in the process of dipping, kneading, precipitation, deposition-precipitation or sol-gel; adding the cobalt salt together or step by step in the methods of blending, ball milling, melting and the like; adding the cobalt salt and the cobalt salt in the processes of dipping, precipitation, deposition-precipitation or sol-gel respectively or step by step; adding the catalyst precursor into a dried filter cake or xerogel obtained by precipitation, deposition-precipitation or sol-gel, or a material after roasting and decomposition; or in the forming stage of sheet beating or strip extruding and the like.

As described above, the catalyst of the present invention further contains an oxide generally regarded as functioning as a carrier, and is not particularly limited herein, and is selected from one or more of silica, alumina, a silica-alumina composite, diatomaceous earth, calcium silicate, zirconia, and titania. In fact, these supports, which not only serve as supports, but also assist in dispersing the active components and promote acetone condensation and dehydration, affect the structural properties of the catalyst, diffusion of products and feedstocks therein, mechanical strength, activity and stability, among other critical parameters.

The carrier alumina may be selected from aluminas produced from aluminum hydroxide produced by a nitric acid process, a sulfuric acid process, a carbonic acid process, a bayer process, a rapid dehydration process, and the like. Since alumina is more commonly used, it will not be described further herein.

The carrier silica may be selected from water glass precipitation, silica powder, hydrolysis of ethyl orthosilicate, silica sol, and the like. The silicon dioxide powder can be obtained by a chemical deposition method, a ball milling method after drying after water glass precipitation, or a method of silica sol spray drying and the like, and the size of the silicon dioxide powder is selected from 10 nm-500 mu m; such as coarse-pore microspherical silica (the average pore diameter is 8.0-12.0nm, the specific surface area is 300-600 m2/g, and the pore volume is 0.8-1.1 ml/g) produced by Qingdao ocean chemical plants, precipitated silica (the content of silica (SiO 2)% is more than or equal to 95.0, the fineness (325-mesh residue)% is less than or equal to 1.8, and the specific surface area is 400-600 m2/g) produced by Guangzhou civil chemical plants, or active white carbon black, or AEROSIL200 of fumed silica of Texaco corporation, the specific surface area is 200m2/g, or silica microspheres obtained by self-made spray drying, the specific surface is 400-500 m2/g, and the size is 2-30 mu m. The silica powder may be added as a carrier in a precipitation or precipitation-precipitation process. The direct precipitation method of water glass is characterized in that water glass is used as a raw material, and an acidic precipitator or an ionic precipitator, such as sulfuric acid, hydrochloric acid, nitric acid, acetic acid, calcium nitrate, zirconyl chloride, magnesium nitrate, cobalt nitrate and the like, is added into the water glass. The precipitant is added to form white jelly, and the white jelly is used after being washed for several times or is added on the basis of the white jelly by a precipitation method of other components. Tetraethoxysilane is used in the preparation of the catalyst of the present invention by a sol-gel process. The silica sol as liquid silicon source may be used directly in the precipitation system of precipitation and deposition-precipitation process.

In order to improve the thermal stability, mechanical strength, pore structure and surface properties of alumina, some inorganic compounds may be added for modification. For example, the modification is carried out by adding silica to alumina. For example, the addition of silica gel or silica-alumina gel to an aluminum hydroxide hydrogel can significantly change the texture properties of the alumina and the acidity or basicity of the support. Rare earth oxide can also be added to obviously improve the thermal stability of the alumina and change the acidity and alkalinity of the carrier. Molecular sieves, barium oxide, magnesium oxide, boric acid and phosphoric acid may also be added to improve the carrier properties.

The support silica or alumina may also be added as a binder in the catalyst prepared as a melt-suction filtration process, so that the resulting catalyst powder can be shaped into the desired form according to the invention.

The shape of the catalyst can be various, such as spherical, strip, columnar, annular and the like, the size is 0.3-15 mm, more preferably 0.5-3 mm, and the requirement of the size is mainly based on the design of the fixed bed reactor, so that the fixed bed reactor is convenient to install, and the requirement of reducing the bed pressure is met. These knowledge are well known to those skilled in the art.

The catalyst preparation method can be obtained by the existing catalyst preparation technology, such as impregnation method, ion exchange method, blending method, kneading method, coprecipitation, deposition-precipitation, ammonium evaporation precipitation, melting-suction filtration, ball milling, sol-gel and other methods. More preferred methods include one or more of impregnation, co-precipitation, deposition-precipitation, sol-gel and ball-milling methods, most of which are well known to those skilled in the art as well known in the art, such as < industrial catalyst design and development > by the general Tao Huang, and "Preparation of Solid Catalysts" by the professor Gerhard Ertl et al.

The catalyst of the present invention is reduced before use, the reducing gas may be hydrogen gas, a mixture of hydrogen gas and nitrogen gas, the hydrogen content in the mixture of hydrogen and nitrogen gas may be any content, for example, 2 vol% to 90 vol%, or pure hydrogen gas may be used. From the viewpoint of temperature control of the catalyst reduction, the larger the space velocity of the gas, the better the reduction. The air speed is large, the heat generated by the reaction can be quickly removed in time, the temperature of the catalyst bed is kept stable, and the catalyst is not damaged by temperature runaway. For example, the space velocity of hydrogen is 300-5000 m³/m³·h^-1. The reduction temperature can be determined according to the composition of the specific catalyst, and for the catalyst provided by the invention, the temperature of the catalyst bed layer can be gradually increased at the speed of 5-20 ℃/h, preferably 5-10 ℃/h, the catalyst bed layer stays at 200 ℃ for 2-8 hours, then the temperature of the catalyst bed layer is gradually increased at the speed of 5-20 ℃/h, preferably 5-10 ℃/h until the temperature reaches 450-500 ℃, and the catalyst bed layer is kept at the temperature for 2-48 hours. And then slowly cooling to room temperature, for example, the cooling rate is 5-20 ℃/h. The amount of hydrogen is adjusted at any time according to the change of the temperature of the catalyst, so that the temperature of a catalyst bed is prevented from being too high, for example, not exceeding 50 ℃. If the catalyst is reduced in the reactor, the temperature of the reduced catalyst is reduced to the reaction temperature, and then the catalyst can be fed for use.

The catalyst of the invention can be used in a fixed bed reactor, and the reaction conditions are as follows: the reaction temperature is 100-190 ℃, the reaction pressure is 0.8-2.5 MPa, and the acetone airspeed is 0.1-1.5 h^-1And the mass ratio of the hydrogen to the acetone is 1-6: 1. The increase of the reaction temperature is beneficial to improving the conversion rate of the acetone and the condensation reaction and the dehydration reaction of the acetone. The reaction pressure is increased, so that the hydrogenation reaction intensity is increased, and the isopropanol selectivity is increased. The influence of the acetone airspeed in the range is small, the airspeed is too large, the acetone conversion rate is reduced, and the one-way yield is reduced. The hydrogen has little influence on the reaction under the condition of enough hydrogen, but the hydrogen is not too much, and the hydrogen influences the retention time of the materials in the catalyst bed layer.

Compared with the existing industrial palladium/resin catalyst, the catalyst of the invention has low cost, the price of the palladium catalyst per ton is as high as dozens of ten thousand yuan, even millions of yuan, and the price of the catalyst of the invention is one tenth of the price. Secondly, the preparation process is relatively simple and convenient and is easy to control, the palladium catalyst is polymerized to prepare granular resin firstly, then the palladium is loaded by exchange, organic matters on the resin are easy to lose, reaction products are polluted, the product chromaticity is increased, and the catalyst of the invention can not lose. And thirdly, the process operation window of the palladium/resin catalyst is narrow, the catalyst is easy to deactivate due to overhigh temperature, the acid amount is reduced, and the catalyst has a wider temperature operation window. The structural stability and operational applicability of the catalyst of the present invention determine its high stability and lifetime. And fourthly, only one product, namely methyl isobutyl ketone, is produced by the palladium catalyst, but the catalyst of the invention not only can produce methyl isobutyl ketone, but also can produce 4-methyl-2-pentanol, and an industrial production device has stronger market adaptability and increased loss resistance.

Detailed Description

The catalysts according to the invention are further illustrated below by way of examples, without the invention being restricted thereto.

Example 1

Aqueous solution I was prepared by dissolving 133.4 grams of cobalt nitrate and 4.7 grams of ammonium fluoride in 322 grams of water in a beaker. In a separate beaker, 74.1 grams of sodium stannate was dissolved in 173 grams of water to make aqueous solution II. The aqueous sodium stannate solution II was poured into a beaker of the aqueous solution I with stirring at 70 ℃ and then with 30 wt% carbonic acidThe aqueous sodium solution was titrated to pH 7.5. 332 g of pseudo-boehmite powder was then added. Pseudo-boehmite is produced by Jiangsu three-agent industry Co., Ltd, and has a specific surface area of 305m²The pore volume is 0.92 mL/g.

Followed by aging at 70 ℃ for 4 hours, then suction filtration and washing until the sodium ion content is below 0.05%. The wet cake was dried, granulated and then calcined at 400 ℃ for decomposition. Finally, the mixture is made into granules with the grain diameter of

The catalyst was then reduced with hydrogen at a temperature programmed to a maximum of 480 ℃. Reducing at 480 ℃ for 2 hours. And cooling to obtain the catalyst. The composition was analyzed by an instrument and the catalyst composition was as follows:

(1) the cobalt accounts for 9 percent of the mass percentage in a metallic state; (2) the tin, the metallic tin and the oxidized tin are calculated by being converted into the metallic tin, the mass percentage content is 11%, and the metallic tin accounts for 45% of the total tin; (3) fluorine, calculated by being converted into simple substance fluorine, with the mass percent content of 0.8%; (4) alumina carrier and the rest.

Comparative example 1

An industrially useful palladium/resin catalyst obtained from Zhejiang Utilization chemical Co., Ltd.

Example 2

Aqueous solution I was prepared by dissolving 88.9 grams of cobalt nitrate and 0.66 grams of sodium fluoride in 208 grams of water in a beaker. In another beaker, 101.1 grams of sodium stannate was dissolved in water to make aqueous solution II. The aqueous sodium stannate solution II was poured into a beaker of the aqueous solution I with stirring at 70 ℃ and then titrated with a 30 wt% aqueous sodium carbonate solution until the pH of the reaction solution was 7.4. 325 grams of pseudo-boehmite powder was then added. Pseudo-boehmite is produced by Jiangsu three-agent industry Co., Ltd, and has a specific surface area of 298m²The pore volume was 1.0 mL/g.

Followed by aging at 75 deg.CAfter 3 hours, it is filtered off with suction and washed until the sodium ion content is below 0.05%. The wet cake was dried, granulated and then calcined at 380 ℃ for decomposition. Finally, the mixture is made into granules with the grain diameter of

The catalyst was then reduced with hydrogen at a temperature of up to 470 ℃ according to a temperature program. Reducing at 470 ℃ for 2 hours. And cooling to obtain the catalyst. The composition was analyzed by an instrument and the catalyst composition was as follows:

(1) the cobalt accounts for 6.0 percent of the metal state by mass percent; (2) the tin, the metallic tin and the oxidized tin are calculated by being converted into the metallic tin, the mass percentage content is 15%, and the metallic tin accounts for 25% of the total tin; (3) fluorine, calculated by being converted into simple substance fluorine, with the mass percent content of 0.1%; (4) alumina carrier and the rest.

Example 3

Aqueous solution I was prepared by dissolving 177.9 grams of cobalt nitrate and 2.3 grams of ammonium fluoride in 420 grams of water in a beaker. In another beaker, 148.3 grams of sodium stannate was dissolved in 350 grams of water to make aqueous solution II. The aqueous sodium stannate solution II was poured into a beaker of the aqueous solution I with stirring at 73 ℃ and then titrated with a 30 wt% aqueous sodium carbonate solution until the pH of the reaction solution was 7.2. 266 grams of pseudo-boehmite powder was then added. Pseudo-boehmite is produced by Jiangsu Sanji industries Co Ltd, and has a specific surface area of 279m²The pore volume is 0.88 mL/g.

Followed by aging at 75 ℃ for 3.5 hours, then suction filtration and washing until the sodium ion content is below 0.05%. The wet cake was dried, granulated and then calcined at 370 ℃ to decompose. Finally, the mixture is made into granules with the grain diameter of

The catalyst was then reduced with hydrogen at a temperature of up to 450 ℃ according to a temperature program. Reducing at 450 ℃ for 3 hours. And cooling to obtain the catalyst. The composition was analyzed by an instrument and the catalyst composition was as follows:

(1) the cobalt accounts for 12 percent of the mass percentage in a metallic state; (2) the tin, the metallic tin and the oxidized tin are calculated by being converted into the metallic tin, the mass percentage content is 22%, and the metallic tin accounts for 40% of the total tin; (3) fluorine, calculated by being converted into simple substance fluorine, with the mass percent content of 0.4%; (4) alumina carrier and the rest.

Example 4

Aqueous solution I was prepared by dissolving 103.8 grams of cobalt nitrate and 3.5 grams of ammonium fluoride in 245 grams of water in a beaker. In another beaker, 47.2 grams of sodium stannate was dissolved in 110 grams of water to make aqueous solution II. The aqueous sodium stannate solution II was poured into a beaker of the aqueous solution I with stirring at 73 ℃ and then titrated with a 30 wt% aqueous sodium carbonate solution until the pH of the reaction solution was 7.2. Then 180 grams of pseudo-boehmite powder and 420 grams of silica sol were added. Pseudo-boehmite is produced by Jiangsu Sanji industries Co Ltd, and has a specific surface area of 279m²The pore volume is 0.88 mL/g. The silica sol stone is produced by Shandong ocean chemical Co., Ltd, and has a model number of SW-30.

(1) the cobalt accounts for 7 percent of the mass percentage in a metallic state; (2) the tin, the metallic tin and the oxidized tin are calculated by being converted into the metallic tin, the mass percentage content is 7%, and the metallic tin accounts for 30% of the total tin; (3) fluorine, calculated by being converted into simple substance fluorine, with the mass percent content of 0.6 percent; (4) alumina-silica composite carrier, the rest.

Example 5

500 g of pseudo-boehmite was kneaded in accordance with a conventional method, and 10 ml of phosphoric acid and 20 ml of sulfuric acid were added at the time of kneading to carry out carrier acid modification. Extruding into 3mm thick strips, drying, and roasting at 500 ℃ to obtain the alumina carrier. Pseudo-boehmite is produced by Jiangsu three-agent industry Co., Ltd, and has a specific surface area of 290m²The pore volume is 0.9 mL/g.

Aqueous solution I was prepared by dissolving 118.6 grams of cobalt nitrate and 4.1 grams of ammonium fluoride in 180 grams of water in a beaker. In another beaker, 92 grams of potassium stannate was dissolved in 200 grams of water to make aqueous solution II.

227 g of the carrier prepared above is taken, firstly the aqueous solution II prepared above is soaked on the carrier, dried and roasted at 350 ℃ for decomposition, and then the aqueous solution I prepared above is soaked on the carrier, dried and roasted at 350 ℃ for decomposition.

The catalyst was then reduced with hydrogen at a temperature of 460 ℃ maximum in a temperature programmed manner. Reducing at 460 ℃ for 3 hours. And cooling to obtain the catalyst. The composition was analyzed by an instrument and the catalyst composition was as follows:

(1) the cobalt accounts for 8 percent of the mass percentage in a metallic state; (2) the tin, the metallic tin and the oxidized tin are calculated by being converted into the metallic tin, the mass percentage content is 13%, and the metallic tin accounts for 50% of the total tin; (3) fluorine, calculated by being converted into simple substance fluorine, with the mass percent content of 0.7%; (ii) a (4) Alumina carrier and the rest.

Example 6

400 g of pseudo-boehmite and 200 g of silica sol were mixed and kneaded according to a conventional method, and 20 ml of sulfuric acid was added during kneading to perform carrier acid modification. Extruding into 3mm thick strips, drying, and roasting at 500 ℃ to obtain the alumina carrier. Pseudo-boehmite is limited by three agents of JiangsuProduction, specific surface area 290m²The pore volume is 0.9 mL/g. The silica sol stone is produced by Shandong ocean chemical Co., Ltd, and has a model number of SW-30.

Example 7

This example is an example of catalyst evaluation.

The method comprises the following steps of filling a catalyst in an oil bath controlled isothermal fixed bed reactor, mixing acetone metered by a metering pump and hydrogen metered by a gas mass flow meter, feeding the mixture into a preheater, vaporizing the acetone, feeding the acetone into a reactor, flowing through a catalyst bed layer, and carrying out condensation, dehydration and hydrogenation series reactions under the catalytic action of the catalyst, wherein the reaction conditions are as follows: the reaction temperature is 160 ℃, the reaction pressure is 1.0MPa, and the space velocity is 0.5h^-1And the mass ratio of hydrogen to acetone was 3: 1.

The catalyst of comparative example 1 was evaluated as: the reaction temperature is 110 ℃, the reaction pressure is 1.0MPa, and the space velocity is 0.5h^-1And the mass ratio of hydrogen to acetone was 3: 1.

The test results are shown in table 1 below.

TABLE 1 test results

As can be seen from the evaluation results in Table 1, compared with the palladium/resin catalyst in comparative example 1, the catalyst of the present invention has higher acetone conversion rate, can produce a large amount of isopropanol as a byproduct while synthesizing methyl isobutyl ketone in high yield, and the isopropanol is a better low molecular solvent, and can wash heavy components generated in the reaction process from the catalyst bed layer, thereby maintaining the stability of the catalyst and prolonging the service life of the catalyst. The catalyst of the present invention has a higher yield of methyl isobutyl ketone than the palladium on resin catalyst of comparative example 1 from a per pass conversion point of view. In addition, the catalyst of the invention is subjected to a stability assessment test for nearly 800h, and shows good stability.

Claims

1. A cobalt-based catalyst for synthesizing methyl isobutyl ketone by using acetone as a raw material through a one-step method is characterized by comprising a carrier and load components of cobalt, tin and fluorine, wherein 20-50% of tin in atomic percentage exists in a metal state, and the rest of tin exists in an oxidation state;

the catalyst comprises the following components in percentage by mass of 100 percent:

(1) the cobalt accounts for 5 to 12 percent of the metal state by mass percent;

(3) fluorine, calculated by the conversion of fluorine element, the mass percent content is 0.05-0.8%;

(4) a carrier, the balance excluding the supported component.

2. A cobalt-based catalyst according to claim 1, wherein the support is alumina, silica, an alumina-silica composite support, or a molecular sieve.

3. A cobalt-based catalyst according to claim 2, wherein the alumina is an acid-modified alumina or a base-modified alumina.

4. A cobalt-based catalyst according to claim 2, wherein the silica is an acid-modified silica or a base-modified silica.

5. The cobalt-based catalyst according to claim 2, wherein the alumina-silica composite support is an acid-modified alumina-silica composite support or a base-modified alumina-silica composite support.