CN107774308B

CN107774308B - Vinyl acetate catalyst

Info

Publication number: CN107774308B
Application number: CN201610750255.9A
Authority: CN
Inventors: 邱鹏远; 杨运信
Original assignee: Sinopec Shanghai Research Institute of Petrochemical Technology; China Petrochemical Corp
Current assignee: Sinopec Shanghai Research Institute of Petrochemical Technology; China Petrochemical Corp
Priority date: 2016-08-29
Filing date: 2016-08-29
Publication date: 2019-12-10
Anticipated expiration: 2036-08-29
Also published as: CN107774308A

Abstract

The invention relates to a vinyl acetate catalyst and a preparation method thereof, and mainly solves the problem of high content of byproduct benzene in the prior art. The invention adopts the technical scheme that the catalyst for synthesizing the vinyl acetate by the acetylene method adopts the activated carbon as a carrier, the active component comprises zinc acetate and a cocatalyst, and the cocatalyst comprises at least one metal element selected from IB elements and at least one metal element selected from IVA elements, thereby better solving the problem and being applicable to the industrial production of synthesizing the vinyl acetate by the acetylene method.

Description

Vinyl acetate catalyst

Technical Field

The invention relates to an acetylene gas phase method vinyl acetate catalyst, a preparation method of the catalyst and a synthetic method of vinyl acetate.

Background

Vinyl acetate, abbreviated as Vinyl Acetate (VAM), is an important organic chemical raw material, is mainly used for producing derivatives such as polyvinyl acetate (PVAc), polyvinyl alcohol (PVOH), vinyl acetate-ethylene copolymer emulsion (VAE) or copolymer resin (EVA), vinyl acetate-vinyl chloride copolymer (EVC), polyacrylonitrile comonomer, acetal resin and the like, and has wide development and utilization values in the aspects of coating, slurry, adhesive, vinylon, film, leather processing, synthetic fiber, soil improvement and the like. With the continuous progress of production technology, the application field is still expanding.

The worldwide vinyl acetate production in 2011 reaches 743.4 million tons/year, and is mainly concentrated in Asia, North America and Western Europe. According to regional capacity statistics, Asia Tai is 398.8 ten thousand tons/year, accounting for 53.6%; north america at 206.3 ten thousand tons/year, accounting for 27.8%; western Europe is 117.1 ten thousand tons/year, accounting for 15.8%; the other areas account for 2.9%. Wherein the yield of the Chinese vinyl acetate is 216.5 ten thousand tons/year.

At present, the main production process routes of vinyl acetate are an ethylene method and an acetylene method. The acetylene method comprises a natural gas acetylene method and a calcium carbide acetylene method. The natural gas acetylene method adopts a fixed bed process, and selects granular zinc acetate/active carbon catalyst; the calcium carbide acetylene method adopts a fluidized bed process and selects powdery zinc acetate/active carbon catalyst. Because of different resource structures, countries and regions such as North America, Western Europe, Nippon singapore and the like basically adopt an ethylene process, while countries and regions such as Korea and India all adopt an acetylene process, and countries and regions such as China, Russia, eastern Europe and the like coexist. With the discovery of new natural gas and shale gas resources in China and the maturity and perfection of the exploitation technology thereof, the natural gas acetylene method vinyl acetate production process has very good prospects in China.

In 1922, Wacker Germany firstly used a method for synthesizing VAM from acetylene in a gas phase, and then the VAM was put into industrial production through the improvement of Hochst company. The catalyst uses zinc acetate as an active component and active carbon as a carrier, and is used up to now. The catalyst has the disadvantages of rapid activity reduction, low production capacity, increased by-products along with the increase of reaction temperature and short service life of the catalyst. Meanwhile, the acetylene method has the advantages of simple technology, cheap and easily obtained catalyst, good activity, high selectivity, low construction cost and the like. Therefore, how to effectively improve the activity and service life of the catalyst becomes an important scientific problem in the field of catalysis, researchers in various countries start to systematically research the problem from aspects of selection and modification of active components, promoters, carriers, catalyst preparation processes and the like, and certain stage results are obtained.

For example, japanese scholars propose two-component oxides (V ₂ O ₅ -ZnO, Fe ₂ O ₃ -ZnO) or three-component oxides (16 zno.32 ₂ O ₃. V ₂ O ₅ and 24 zno.8cr ₂ O ₃. V ₂ O ₅) as active components of catalysts, although the catalysts have higher activity than Zn (oac) ₂/C catalysts at 250 ℃, industrialization cannot be achieved due to the disadvantages of high reaction temperature, high cost, rapid decrease in activity, and the like.

For example, Chinese patent (CN 1903435A, a catalyst for vinyl acetate synthesis and a preparation method thereof) selects bismuth subcarbonate as the cocatalyst, so that the space-time yield of vinyl acetate of the catalyst is increased from 2.02t/m ³ d to 2.67t/m ³ d, and the catalyst activity is increased by 32.2%.

For a long time, many scholars at home and abroad have not succeeded in experiments of replacing the activated carbon carrier with silica gel, alumina, aluminum silicate, molecular sieve and the like. The studies in the literature (chemical engineering, 1962,85(16): 1; petrochemical, 1979, (8)7:49) have found that the catalyst activity is much lower than that of the activated carbon supported catalyst when silica gel, alumina, aluminum silicate and molecular sieves are used as the carriers. Practice proves that the activated carbon is not replaceable as a carrier of the acetylene method vinyl acetate catalyst. Meanwhile, researchers consider modifying the activated carbon carrier, so that the purpose of improving the performance of the carrier is achieved. For example, the activity of the catalyst prepared by using activated carbon with 15 percent of nitric acid by mass as a carrier is improved by 5.36 percent compared with the catalyst prepared by using untreated activated carbon as a carrier by the research of documents (petrochemical industry, 2004,33(11): 1024). Chinese patent CN 102029193A, an active carbon used as a catalyst carrier and a treatment method and application thereof, selects hydrogen peroxide to carry out pretreatment on the active carbon carrier, and the result shows that the catalytic activity of the catalyst prepared by the active carbon treated by the method is improved by 2-15%. Chinese patent (CN 102284304a, a preparation method of a high-efficiency catalyst for synthesizing vinyl acetate by an acetylene method) selects a series of oxidants such as sulfuric acid, potassium permanganate, and ammonium persulfate in addition to hydrogen peroxide to pretreat activated carbon for preparation of a catalyst for synthesizing vinyl acetate. Although the activity of the catalyst can be improved to a certain extent by selecting the oxidant to carry out pretreatment on the activated carbon carrier, most of the activated carbon treated by the acid or other oxidants needs to be washed and extracted for a long time to make the activated carbon neutral, the drying time is long, and the production time and the cost of the catalyst are increased.

With the recent continuous operation of new and expanded vinyl acetate plants in China, the market of vinyl acetate in China has become saturated and even has been in excess. Therefore, how to develop the downstream market of vinyl acetate is urgent to develop a downstream product of vinyl acetate with high added value. And improving the quality of the vinyl acetate product is one of the important precondition factors for developing downstream products with high added value.

Vinyl acetate is used for synthesizing vinyl acetate-ethylene copolymer (VAE) emulsion which is used for cigarette glue in the cigarette production process, but at present, only the ethylene vinyl acetate product index in China reaches the quality requirement of the cigarette glue used in the cigarette industry. The vinyl acetate product produced by the acetylene method contains a small amount of byproduct benzene (<5ppmw), so that the application of the vinyl acetate product to the production of the cigarette adhesive raw material VAE emulsion is restricted, and the problem of how to reduce the byproduct benzene in the vinyl acetate product produced by the acetylene method becomes a core problem restricting the application of the vinyl acetate product to the cigarette adhesive raw material. The research work of academia and industry on the acetylene method vinyl acetate catalyst mainly focuses on improving the catalyst activity, the catalyst service life and the like, and the problem of improving the selectivity of the catalyst, particularly reducing the content of the byproduct benzene, is not reported.

Disclosure of Invention

One of the technical problems to be solved by the invention is the problem of high content of byproduct benzene in the prior art, and provides a novel vinyl acetate catalyst which has the characteristic of low content of generated byproduct benzene.

The second technical problem to be solved by the present invention is to provide a method for preparing a catalyst corresponding to the first technical problem.

The third technical problem to be solved by the present invention is to provide a method for synthesizing vinyl acetate by using the catalyst described in one of the above technical problems.

In order to solve one of the above technical problems, the technical scheme adopted by the invention is as follows: the vinyl acetate catalyst adopts active carbon as a carrier, the active component comprises zinc acetate and a cocatalyst, and the cocatalyst comprises at least one metal element selected from IB elements and at least one metal element selected from IVA elements.

The addition of the cocatalyst obviously reduces the generation amount of impurity benzene.

In the technical scheme, the catalyst composition can be free of alkali metal acetate, for example, free of potassium acetate, and the alkali metal acetate causes the content of harmful impurity benzene in the product to be increased.

In the above technical scheme, the activated carbon is preferably at least one of coal activated carbon, coconut shell activated carbon, apricot shell activated carbon and bamboo activated carbon.

In the technical scheme, the specific surface area of the activated carbon is preferably 1000-1500 m ²/g, and the adsorption pore volume is preferably 0.60-1.00 cm ³/g.

In the above technical solution, the IB metal is preferably at least one selected from copper, silver and gold.

In the above technical solution, the IVA element is selected from at least one of germanium, tin, and lead.

In the above technical solution, it is further preferable to include Ag or Au of IB and Ge of IVA metal at the same time, and in this case, IVA metal and IB metal have a synergistic effect in reducing the benzene content in the product. It is noted that no such synergy is found between Sn and Au, and between Sn and Cu.

As another preferable technical scheme, Ge or Pb of IVA metal and Au and Ag of IB metal are simultaneously included, and the metal elements have synergistic effect on reducing the benzene content in the product.

As a further preferred solution, Ge and Pb of the IVA metal and Au and Ag of the IB metal are included together, in which case the above-mentioned metal elements have a synergistic effect in reducing the benzene content in the product.

In the technical scheme, the content of zinc acetate in the catalyst is preferably 50-300 g/L, and more preferably 80-200 g/L; the content of the cocatalyst is preferably 0.45-8.00 g/L, and more preferably 1.00-5.00 g/L.

To solve the second technical problem, the technical solution of the present invention is as follows: the method for producing the catalyst in the technical scheme of one of the technical problems comprises the following steps:

Mixing zinc acetate and cocatalyst solution with carrier according to the composition of catalyst.

drying.

In the technical scheme, the compound of the IVA metal is preferably at least one of stannous chloride, stannous nitrate, germanium tetrachloride, germanium nitrate, lead acetate and lead nitrate; more preferably at least one selected from lead acetate and germanium nitrate; the compound of the metal in the IB is preferably at least one of copper acetate, copper nitrate, silver acetate, silver nitrate, silver tetrafluoroborate, ammonium tetrachloroaurate and chloroauric acid; more preferably at least one selected from silver nitrate and ammonium tetrachloroaurate.

To solve the third technical problem, the technical scheme of the invention is as follows: the vinyl acetate synthesis method takes acetic acid and acetylene as raw materials, and the vinyl acetate is generated by reaction in the presence of the catalyst in any one of the technical schemes of the technical problems.

^-1The key point of the invention is the selection of a catalyst, and a person skilled in the art knows how to determine a proper reaction temperature, reaction time, reaction pressure and material ratio according to actual needs.

The contents of all components in the reaction product are analyzed by a gas chromatography-mass spectrometer (GC-MS), and the space-time yield of the vinyl acetate of the catalyst is calculated.

Compared with the prior art, the key point of the invention is that the active component of the catalyst comprises zinc acetate and at least one metal element compound selected from IVA and IB, which is beneficial to improving the selectivity of the catalyst and reducing the content of byproduct benzene in the product.

Experimental results show that when the catalyst is adopted, the space-time yield of the vinyl acetate of the catalyst reaches 83.2 g/(L.h), the benzene content in a reaction mixture is reduced to 3600ppbw, and a better technical effect is achieved, particularly when the active component in the catalyst simultaneously comprises zinc acetate, at least one metal element compound selected from IVA and at least one metal element compound selected from IB, a more prominent technical effect is achieved, and the catalyst can be used in the industrial production of the vinyl acetate. The invention is further illustrated by the following examples.

Detailed Description

[ example 1 ]

The preparation of the catalyst comprises the steps of fully mixing 105g of zinc acetate (Zn (OAc) ₂) and 2.80g of Pb-containing lead acetate (Pb (OAc) ₂.3H ₂ O) and dissolving in an acetic acid water solution to obtain 350ml of impregnation liquid with the pH value of 4.8, immersing 1L of cylindrical coal-based activated carbon carrier with the diameter of 3mm, the length of 2cm, the pore volume of 0.80cm ³/g and the specific surface area of 1200m ²/g in the impregnation liquid, standing for 3H and drying at 110 ℃ to obtain the catalyst, and measuring the zinc acetate content of the catalyst by ICP to be 105g/L and the Pb content to be 2.80 g/L.

The synthesis of vinyl acetate comprises the steps of filling 30ml of catalyst in a miniature fixed bed reactor, testing leakage by using N ₂, fully purging the system by using N ₂, heating the system, closing N ₂, sequentially cutting in acetylene and starting a acetic acid pump, controlling the reaction temperature to 178 ℃, the reaction pressure to be 0.25atm, the volume space velocity of raw materials to be 300h ^-1, keeping the molar ratio of acetylene to acetic acid to be 6:1, and stopping the reaction after continuously reacting for 50 h.

Analysis of the reaction mixture: the reaction mixture obtained by the above reaction was analyzed by gas chromatography-mass spectrometer (GC-MS).

The calculated catalyst space time yield of vinyl acetate was 83.2 g/(L.h), and the benzene content in the reaction mixture was 3600 ppbw. For ease of illustration and comparison, the catalyst composition, the vinyl acetate space time yield of the catalyst, and the benzene content of the reaction mixture are shown in Table 1.

[ example 2 ]

the preparation of the catalyst comprises the steps of fully mixing 105g of zinc acetate (Zn (OAc) ₂) and 2.80g of Au-containing ammonium tetrachloroaurate (NH ₄ AuCl ₄ & 2H ₂ O) and dissolving the mixture in an acetic acid water solution to obtain 350ml of impregnation liquid with the pH value of 4.8, soaking 1L of cylindrical coal activated carbon carrier with the diameter of 3mm, the length of 2cm, the pore volume of 0.80cm ³/g and the specific surface area of 1200m ²/g in the impregnation liquid, standing for 3H and drying at the temperature of 110 ℃ to obtain the catalyst, and measuring the ICP content of the catalyst to be 105g/L and the Au content to be 2.80 g/L.

And (3) product analysis: and cooling, decompressing and separating a reaction mixture obtained by the reaction, and analyzing a liquid phase by using a gas chromatography-mass spectrometer (GC-MS).

The calculated catalyst space time yield of vinyl acetate was 83.9 g/(L.h) and the benzene content in the reaction mixture was 3700 ppbw. For ease of illustration and comparison, the catalyst composition, the vinyl acetate space time yield of the catalyst, and the benzene content of the reaction mixture are shown in Table 1.

[ COMPARATIVE EXAMPLE 1 ]

Are comparative examples of [ example 1 ] and [ example 2 ].

The preparation of the catalyst comprises the steps of dissolving 105g of zinc acetate (Zn (OAc) ₂) in an acetic acid water solution to obtain an impregnation liquid with the pH value of 4.8, impregnating 1L of cylindrical activated carbon carrier with the diameter of 3mm, the length of 2cm, the pore volume of 0.80cm ³/g and the specific surface area of 1200m ²/g in the impregnation liquid, standing for 3h, and drying at 110 ℃ to obtain the catalyst, wherein the zinc acetate content of the catalyst is 105g/L through ICP measurement.

The catalyst has a calculated vinyl acetate space-time yield of 64.8 g/(L.h) and a benzene content of 5500ppbw in the reaction mixture. For ease of illustration and comparison, the catalyst composition, the vinyl acetate space time yield of the catalyst, and the benzene content of the reaction mixture are shown in Table 1.

[ COMPARATIVE EXAMPLE 2 ]

The preparation of the catalyst comprises the steps of fully mixing 105g of zinc acetate (Zn (OAc) ₂), 6.5g of potassium acetate (KOAc), and 2.80g of Au-containing ammonium tetrachloroaurate (NH ₄ AuCl ₄ & 2H ₂ O) and dissolving in an acetic acid water solution to obtain 350ml of impregnation liquid with the pH value of 4.8, immersing 1L of cylindrical activated carbon carrier with the diameter of 3mm, the length of 2cm, the pore volume of 0.80cm ³/g and the specific surface area of 1200m ²/g in the impregnation liquid, standing for 3H and drying ICP at 110 ℃ to obtain the catalyst, wherein the zinc acetate content of the catalyst is 105g/L, the potassium acetate content is 6.5g/L, and the Au content is 2.80 g/L.

The space-time yield of vinyl acetate of the catalyst was calculated to be 98.6 g/(L.h), and the benzene content in the reaction mixture was 6400 ppbw. For ease of illustration and comparison, the catalyst composition, the vinyl acetate space time yield of the catalyst, and the benzene content of the reaction mixture are shown in Table 1.

[ example 3 ]

The preparation of the catalyst comprises the steps of fully mixing 105g of zinc acetate (Zn (OAc) ₂) and stannous chloride (SnCl ₂ & 2H ₂ O) containing 2.80g of Sn, dissolving the mixture in an acetic acid water solution to obtain 350ml of impregnation liquid with the pH value of 4.8, impregnating 1L of cylindrical coal-based activated carbon carrier with the diameter of 3mm, the length of 2cm, the pore volume of 0.80cm ³/g and the specific surface area of 1200m ²/g in the impregnation liquid, standing the impregnated cylindrical coal-based activated carbon carrier for 3H and drying the impregnated cylindrical coal-based activated carbon carrier at the temperature of 110 ℃ to obtain the catalyst, and measuring the zinc acetate content of the catalyst by ICP to be 105g/L and the Sn content to be 2.80 g/L.

The calculated catalyst space time yield of vinyl acetate was 82.4 g/(L.h), and the benzene content in the reaction mixture was 3800 ppbw. For ease of illustration and comparison, the catalyst composition, the vinyl acetate space time yield of the catalyst, and the benzene content of the reaction mixture are shown in Table 1.

[ example 4 ]

The preparation of the catalyst comprises the steps of fully mixing 105g of zinc acetate (Zn (OAc) ₂) and 2.80g of Cu-containing copper acetate (Cu (OAc) ₂. H ₂ O) and dissolving in an acetic acid water solution to obtain 350ml of impregnation liquid with the pH value of 4.8, impregnating 1L of cylindrical coal-based activated carbon carrier with the diameter of 3mm, the length of 2cm, the pore volume of 0.80cm ³/g and the specific surface area of 1200m ²/g in the impregnation liquid, standing for 3H and drying at 110 ℃ to obtain the catalyst, and measuring the zinc acetate content of the catalyst by ICP to be 105g/L and the Cu content to be 2.80 g/L.

The catalyst had a calculated vinyl acetate space-time yield of 81.6 g/(L.h) and a benzene content of 3900ppbw in the reaction mixture. For ease of illustration and comparison, the catalyst composition, the vinyl acetate space time yield of the catalyst, and the benzene content of the reaction mixture are shown in Table 1.

[ example 5 ]

The preparation of the catalyst comprises the steps of fully mixing 105g of zinc acetate (Zn (OAc) ₂) and germanium nitrate (Ge (NO ₃) ₄) containing 2.80g of Ge, dissolving the mixture in an acetic acid water solution to obtain 350ml of impregnation liquid with the pH value of 4.8, impregnating 1L of cylindrical coal activated carbon carrier with the diameter of 3mm, the length of 2cm, the pore volume of 0.80cm ³/g and the specific surface area of 1200m ²/g in the impregnation liquid, standing for 3h, and drying at 110 ℃ to obtain the catalyst, wherein the zinc acetate content of the catalyst is 105g/L and the Ge content of 2.80g/L are measured by ICP.

The calculated catalyst space time yield of vinyl acetate was 82.5 g/(L.h) and the benzene content of the reaction mixture was 2800 ppbw. For ease of illustration and comparison, the catalyst composition, the vinyl acetate space time yield of the catalyst, and the benzene content of the reaction mixture are shown in Table 1.

[ COMPARATIVE EXAMPLE 3 ]

The preparation of the catalyst comprises the steps of fully mixing 105g of zinc acetate (Zn (OAc) ₂), 6.5g of potassium acetate (KOAc), and 2.80g of Ge nitrate (Ge (NO ₃) ₄) to be dissolved in an acetic acid aqueous solution to obtain 350ml of impregnation liquid with the pH of 4.8, immersing 1L of cylindrical coal activated carbon carrier with the diameter of 3mm, the length of 2cm, the pore volume of 0.80cm ³/g and the specific surface area of 1200m ²/g in the impregnation liquid, standing for 3h, and drying at 110 ℃ to obtain the catalyst, wherein the zinc acetate content of the catalyst is 105g/L, the potassium acetate content of 6.5g/L and the Ge content of 2.80g/L are measured by ICP.

The calculated catalyst has a vinyl acetate space-time yield of 94.9 g/(L.h) and a benzene content of 5200ppbw in the reaction mixture. For ease of illustration and comparison, the catalyst composition, the vinyl acetate space time yield of the catalyst, and the benzene content of the reaction mixture are shown in Table 1.

[ example 6 ]

The preparation of the catalyst comprises the steps of fully mixing 105g of zinc acetate (Zn (OAc) ₂) and silver nitrate (AgNO ₃) containing 2.80g of Ag, dissolving the mixture in an acetic acid water solution to obtain 350ml of impregnation liquid with the pH value of 4.8, impregnating 1L of cylindrical coal-based activated carbon carrier with the diameter of 3mm, the length of 2cm, the pore volume of 0.80cm ³/g and the specific surface area of 1200m ²/g in the impregnation liquid, standing for 3h, and drying at 110 ℃ to obtain the catalyst, wherein the zinc acetate content of the catalyst is 105g/L and the Ag content of 2.80g/L is measured by ICP.

The calculated catalyst space time yield of vinyl acetate was 85.3 g/(L.h) and the benzene content in the reaction mixture was 2200 ppbw. For ease of illustration and comparison, the catalyst composition, the vinyl acetate space time yield of the catalyst, and the benzene content of the reaction mixture are shown in Table 1.

[ COMPARATIVE EXAMPLE 4 ]

The preparation of the catalyst comprises the steps of fully mixing 105g of zinc acetate (Zn (OAc) ₂), 6.5g of potassium acetate (KOAc) and 2.80g of Ag-containing silver nitrate (AgNO ₃) and dissolving the mixture in an acetic acid water solution to obtain 350ml of impregnation liquid with pH of 4.8, immersing 1L of cylindrical coal-based activated carbon carrier with the diameter of 3mm, the length of 2cm, the pore volume of 0.80cm ³/g and the specific surface area of 1200m ²/g in the impregnation liquid, standing for 3h and drying at 110 ℃ to obtain the catalyst, and measuring the zinc acetate content of the catalyst by ICP (inductively coupled plasma) to be 105g/L, the potassium acetate content to be 6.5g/L and the Ag content to be 2.80 g/L.

The calculated catalyst space time yield of vinyl acetate was 96.8 g/(L.h), the benzene content in the reaction mixture was 5800 ppbw. For ease of illustration and comparison, the catalyst composition, the vinyl acetate space time yield of the catalyst, and the benzene content of the reaction mixture are shown in Table 1.

[ example 7 ]

The preparation of the catalyst comprises the steps of fully mixing 105g of zinc acetate (Zn (OAc) ₂), 1.05g of Ge nitrate (Ge (NO ₃) ₄) and 1.75gAu of ammonium tetrachloroaurate (NH ₄ AuCl ₄.2H ₂ O) and dissolving in an acetic acid aqueous solution to obtain 350ml of impregnation liquid with the pH value of 4.8, immersing 1L of cylindrical activated carbon carrier with the diameter of 3mm, the length of 2cm, the pore volume of 0.80cm ³/g and the specific surface area of 1200m ²/g in the impregnation liquid, standing for 3H and drying at 110 ℃ to obtain the catalyst, and measuring the ICP content of the catalyst to be 105g/L, the Ge content of 1.05g/L and the Au content of 1.75 g/L.

The calculated catalyst space time yield of vinyl acetate was 82.9 g/(L.h) and the benzene content in the reaction mixture was 1800 ppbw. For ease of illustration and comparison, the catalyst composition, the vinyl acetate space time yield of the catalyst, and the benzene content of the reaction mixture are shown in Table 1.

[ example 8 ]

The preparation of the catalyst comprises the steps of fully mixing 105g of zinc acetate (Zn (OAc) ₂), 1.05g of Ge nitrate (Ge (NO ₃) ₄) and 1.75g of Ag containing silver nitrate (AgNO ₃) and dissolving the mixture in an acetic acid water solution to obtain 350ml of impregnation liquid with the pH value of 4.8, soaking 1L of cylindrical activated carbon carrier with the diameter of 3mm, the length of 2cm, the pore volume of 0.80cm ³/g and the specific surface area of 1200m ²/g in the impregnation liquid, standing for 3h and drying at 110 ℃ to obtain the catalyst ICP, and measuring the zinc acetate content of the catalyst to be 105g/L, the Ge content to be 1.05g/L and the Ag content to be 1.75g/L by ICP measurement.

The calculated catalyst has a vinyl acetate space-time yield of 83.6 g/(L.h) and a benzene content of 1380ppbw in the reaction mixture. For ease of illustration and comparison, the catalyst composition, the vinyl acetate space time yield of the catalyst, and the benzene content of the reaction mixture are shown in Table 1.

[ COMPARATIVE EXAMPLE 5 ]

The preparation of the catalyst comprises the steps of fully mixing 105g of zinc acetate (Zn (OAc) ₂), stannous chloride (SnCl ₂.2H ₂ O) containing 1.05g of Sn and ammonium tetrachloroaurate (NH ₄ AuCl ₄.2H ₂ O) containing 1.75g of Au, dissolving the mixture in an acetic acid aqueous solution to obtain 350ml of impregnation liquid with the pH value of 4.8, immersing 1L of cylindrical coal-based activated carbon carrier with the diameter of 3mm, the length of 2cm, the pore volume of 0.80cm ³/g and the specific surface area of 1200m ²/g in the impregnation liquid, standing for 3H, and drying at 110 ℃ to obtain the catalyst, wherein the zinc acetate content of the catalyst is 105g/L, the Sn content is 1.05g/L, and the ICP content is 1.75 g/L.

The calculated catalyst space time yield of vinyl acetate was 83.5 g/(L.h), the benzene content in the reaction mixture was 3750 ppbw. For ease of illustration and comparison, the catalyst composition, the vinyl acetate space time yield of the catalyst, and the benzene content of the reaction mixture are shown in Table 1.

[ COMPARATIVE EXAMPLE 6 ]

The preparation of the catalyst comprises the steps of fully mixing 105g of zinc acetate (Zn (OAc) ₂), stannous chloride (SnCl ₂.2H ₂ O) containing 1.05g of Sn and copper acetate (Cu (OAc) ₂. H ₂ O) containing 1.75g of Cu, dissolving the mixture in an acetic acid water solution to obtain 350ml of impregnation liquid with the pH value of 4.8, immersing 1L of cylindrical coal activated carbon carrier with the diameter of 3mm, the length of 2cm, the pore volume of 0.80cm ³/g and the specific surface area of 1200m ²/g in the impregnation liquid, standing for 3H, and drying at 110 ℃ to obtain the catalyst, wherein the zinc acetate content of the catalyst is 105g/L, the Sn content is 1.05g/L and the Cu content is 1.75g/L through ICP measurement.

The calculated catalyst space time yield of vinyl acetate was 85.6 g/(L.h), the benzene content in the reaction mixture was 3860 ppbw. For ease of illustration and comparison, the catalyst composition, the vinyl acetate space time yield of the catalyst, and the benzene content of the reaction mixture are shown in Table 1.

[ example 9 ]

The preparation of the catalyst comprises the steps of fully mixing 105g of zinc acetate (Zn (OAc) ₂), 1.05g of Ge nitrate (Ge (NO ₃) ₄), 1.05g of Au-containing tetrachloroaurate (NH ₄ AuCl ₄ & 2H ₂ O) and 0.70g of Ag-containing silver nitrate (AgNO ₃) and dissolving in an acetic acid aqueous solution to obtain 350ml of impregnation liquid with pH of 4.8, immersing 1L of cylindrical coal-based activated carbon carrier with the diameter of 3mm, the length of 2cm, the pore volume of 0.80cm ³/g and the specific surface area of 1200m ²/g in the impregnation liquid, standing for 3H and drying at 110 ℃ to obtain the catalyst, wherein the ICP determination shows that the zinc acetate content of the catalyst is 105g/L, the Ge content is 1.05g/L, the Au content is 1.05g/L and the Ag content is 0.70 g/L.

The calculated catalyst space time yield of vinyl acetate was 82.2 g/(L.h), the benzene content in the reaction mixture was 880 ppbw. For ease of illustration and comparison, the catalyst composition, the vinyl acetate space time yield of the catalyst, and the benzene content of the reaction mixture are shown in Table 1.

[ example 10 ]

The preparation of the catalyst comprises the steps of fully mixing 105g of zinc acetate (Zn (OAc) ₂), 1.05g of Pb-containing lead acetate (Pb (OAc) ₂.3H ₂ O), 1.05g of Au-containing ammonium tetrachloroaurate (NH ₄ AuCl ₄.2H ₂ O) and 0.70g of Ag-containing silver nitrate (AgNO ₃) and dissolving the mixture in an acetic acid aqueous solution to obtain 350ml of impregnation liquid with pH of 4.8, impregnating 1L of cylindrical activated carbon carrier with the diameter of 3mm, the length of 2cm, the pore volume of 0.80cm ³/g and the specific surface area of 1200m ²/g in the impregnation liquid, standing the impregnated activated carbon carrier for 3H and drying the impregnated activated carbon carrier at 110 ℃ to obtain the catalyst, and measuring the zinc acetate content of the catalyst by ICP, the Pb content of 1.05g/L, the Au content of 1.05g/L and the Ag content of 0.70g/L by the ICP.

The calculated catalyst space time yield of vinyl acetate was 82.5 g/(L.h), and the benzene content in the reaction mixture was 1050 ppbw. For ease of illustration and comparison, the catalyst composition, the vinyl acetate space time yield of the catalyst, and the benzene content of the reaction mixture are shown in Table 1.

[ example 11 ]

The catalyst is prepared by mixing and dissolving 105g of zinc acetate (Zn (OAc) ₂), 0.40g of Ge nitrate (Ge (NO ₃) ₄), 0.65g of Pb-containing lead acetate (Pb (OAc) ₂.3H ₂ O), 1.05g of Au-containing ammonium tetrachloroaurate (NH ₄ AuCl ₄.2H ₂ O) and 0.70g of Ag-containing silver nitrate (AgNO ₃) in an aqueous acetic acid solution to obtain 350ml of an impregnation solution with pH of 4.8, and immersing 1L of a cylindrical activated carbon carrier with a diameter of 3mm, a length of 2cm, a pore volume of 0.80cm ³/g and a specific surface area of 1200m ²/g in the impregnation solution, standing for 3H and drying at 110 ℃ to obtain the catalyst, wherein the catalyst has 105g/L of zinc acetate, 0.40g/L of Ge, 0.65g/L of Pb, 1.05g/L of Au, and 70g/L of Ag, as measured by ICP.

The calculated catalyst space time yield of vinyl acetate was 83.6 g/(L.h) and the benzene content in the reaction mixture was 750 ppbw. For ease of illustration and comparison, the catalyst composition, the vinyl acetate space time yield of the catalyst, and the benzene content of the reaction mixture are shown in Table 1.

As can be seen from the comparison of comparative example 1 with examples 1 to 11, the IVA metal or IB metal has the effect of reducing the benzene content as an impurity in the reaction mixture.

It can be seen from example 7 in comparison to examples 2 and 5 that Au and Ge have a synergistic effect in reducing the content of benzene as an impurity in the reaction mixture. As can be seen by comparing example 8 with examples 5 and 6, Ge and Ag have a synergistic effect in reducing the content of benzene as an impurity in the reaction mixture. However, comparison of comparative example 5 with examples 3 and 2, or comparison of comparative example 6 with examples 3 and 4 shows that there is no synergy between Sn and Au, or Sn and Cu, in reducing the content of benzene as an impurity in the reaction mixture.

Example 9 in comparison to examples 7 and 8 shows that Au and Ag act synergistically in reducing the level of benzene impurity in the reaction mixture.

Example 11 in comparison to examples 9 and 10 shows that Ge and Pb act synergistically in reducing the level of benzene as an impurity in the reaction mixture.

TABLE 1

Claims

1. The catalyst adopts active carbon as a carrier, the active component comprises zinc acetate and a cocatalyst, and the cocatalyst is at least one metal element of germanium and lead and at least one metal element of silver and gold; wherein, the content of zinc acetate in the catalyst is as follows: 50-300 g/L; the content of the cocatalyst is as follows: 0.45-8.00 g/L.

2. The catalyst according to claim 1, wherein the activated carbon is at least one of coal-based activated carbon, coconut shell activated carbon, apricot shell activated carbon, and bamboo-based activated carbon.

3. The catalyst according to claim 1, wherein the activated carbon has a specific surface area of 1000 to 1500m ²/g and an adsorption pore volume of 0.60 to 1.00cm ³/g.

4. A method for producing the catalyst of claim 1, comprising the steps of:

Mixing zinc acetate and a solution of a cocatalyst with a carrier according to the composition of a catalyst;

Drying.

5. A method for synthesizing vinyl acetate, which takes acetic acid and acetylene as raw materials and synthesizes the vinyl acetate under the catalyst of any one of claims 1 to 3.

6. The synthesis method according to claim 5, wherein the raw material composition comprises acetylene, acetic acid ═ 1 (5-12) in molar ratio.