Catalyst, system and method for preparing n-propyl acetate and n-propyl alcohol from propylene and acetic acid

Abstract

The invention relates to a catalyst, system and method for preparing n-propyl acetate and n-propyl alcohol from propylene and acetic acid, and the method comprises the following steps: propylene, acetic acid and oxygen are subjected to an oxygen acetylation reaction under the action of a palladium-antimony bimetallic supported catalyst to generate allyl acetate; after separation and purification, allyl acetate enters a hydrogenation reactor, n-propyl acetate is generated through hydrogenation under the action of a Pd catalyst, after hydrogen is separated through a gas-liquid separator, n-propyl acetate enters a reactive distillation tower, n-propyl acetate and methyl alcohol are subjected to transesterification under the action of alkaline ion exchange resin, and n-propyl alcohol and methyl acetate are generated. And separating and purifying to obtain methyl acetate and normal propyl alcohol. Compared with the prior art, the method is good in atom economy, low in raw material cost, high in catalyst activity, good in stability, high in production continuity degree, simple in subsequent separation and purification, high in product purity and suitable for large-scale production.

Description

Technical Field

[0001] The invention relates to the technical field of preparation of acetate and n-propanol, and in particular to a catalyst, system and method for preparing n-propyl acetate and n-propanol from propylene and acetic acid. Background Art

[0002] n-Propanol is a widely used chemical product, mainly used as a solvent and chemical intermediate. It is currently widely used in coatings, paints, adhesives, cosmetics, plastics and fungicides. It can also be used to produce n-propyl acetate, di-n-propylamine, propanol urea, etc.

[0003] At present, there are mainly two kinds of production techniques for domestic n-propyl alcohol, and the first is the ethylene carbonyl synthesis method, which is a raw material of ethylene, synthesis gas and hydrogen, and produces propionic aldehyde through low-pressure carbonyl synthesis process, and then produces n-propyl alcohol by gas phase hydrogenation process, and the technique is relatively mature, but in the production process of existing technique, there is a problem that the three-phase azeotrope containing propyl propionate, water and n-propyl alcohol cannot be recycled, and a series of problems such as catalyst loss, large heat loss, high solvent recovery energy consumption, and poor tail gas treatment effect. At present, there are still some problems in the improved n-propyl alcohol production technology in China. For example, CN101225018A discloses a removal method of byproduct propyl propionate in a process for preparing n-propyl alcohol by propionic aldehyde hydrogenation, and this technique removes propyl propionate in a lightness removal tower by forming a form of n-propyl alcohol-propyl propionate-water ternary azeotrope by water replenishment, which will certainly cause the loss of n-propyl alcohol. The second is the allyl alcohol hydrogenation method, which uses allyl alcohol as a raw material to undergo a hydroformylation reaction to generate 4-hydroxybutyraldehyde, which is then hydrogenated to produce 1,4-butanediol, while producing n-propanol as a byproduct. Since n-propanol is a byproduct in this method, the yield is too low.

[0004] At present, the main application of n-propyl alcohol is the production of n-propyl acetate, which accounts for about 65% of the market demand for n-propyl alcohol. n-propyl acetate is a commonly used chemical raw material. It has excellent solubility for a variety of synthetic resins. It is an effective solvent for ethyl cellulose, nitrocellulose, styrene, methacrylate resin, etc. It is also commonly used as a solvent for organic synthesis processes and coatings, printing inks, etc. It is also a commonly used dehydrating agent in industry.

[0005] At present, although the production technology of n-propyl acetate in my country is relatively mature, its shortcomings are also obvious. The traditional production method of n-propyl acetate is to use concentrated sulfuric acid as a catalyst and adopt an intermittent production process, that is, acetic acid and n-propanol undergo esterification reaction under the catalysis of concentrated sulfuric acid to produce n-propyl acetate. The production process has a low degree of automation and low production efficiency. Secondly, this process has many side reactions and requires subsequent complex processing processes, and the product quality is difficult to control. Most importantly, the use of concentrated sulfuric acid will cause serious pollution to the environment, which is contrary to the current green and environmentally friendly production concept. Current research mainly focuses on the improvement of catalysts and separation processes. Patent CN021450862 reports the use of ionic liquids [Hmim] + BF4 - Catalytic esterification method. However, ionic liquids are expensive, catalyst post-treatment steps are complicated, and energy consumption is high. 200510027919.0 discloses a method for extracting and rectifying propyl acetate, but this method has the problems of large amount of extractant used, low reuse rate of acidic homogeneous catalyst, waste water and waste residue generated in the separation process of the product, and environmental pollution. In addition, the economic benefits of the esterification process of n-propyl acetate are greatly affected by the fluctuation of n-propyl alcohol production and price. The insufficient production capacity of n-propyl alcohol and the rise in price have affected the application of n-propyl acetate to a certain extent.

[0006] At present, the use of Pd catalyst to catalyze propylene, acetic acid and oxygen to generate allyl acetate has been industrialized, and n-propyl acetate can be obtained by selective hydrogenation of allyl acetate. This process can use heterogeneous catalysts to reduce investment and has good economic benefits. The main problems faced in the industrial production of allyl acetate are low catalyst efficiency and poor stability, and there are few studies on the preparation of n-propyl acetate by hydrogenation of allyl acetate. Patent US6936730B1 discloses a method and catalyst for preparing n-propyl acetate by hydrogenation of allyl acetate. The method uses a palladium-based metal catalyst supported by porous alumina or silicon oxide, and obtains a yield of n-propyl acetate of more than 99%. However, the hydrogenation solution system has high requirements during the reaction process. The acetic acid content in allyl acetate needs to be less than 1%. N-propyl acetate is used as a solvent. The mass ratio of allyl acetate to n-propyl acetate in the solution is only 1:12.9, and a large amount of materials containing allyl acetate are circulated during the reaction, resulting in low reaction efficiency and high energy consumption. Patent CN101855195A discloses a method for manufacturing n-propyl acetate and allyl acetate, which uses propylene, oxygen and acetic acid as raw materials to manufacture allyl acetate, and then uses allyl acetate as a raw material for hydrogenation reaction to prepare n-propyl acetate. The byproducts of the reaction of propylene, acetic acid and oxygen in this method are very complex, containing a large amount of aldehydes and colored impurities, and need to be decolorized by light radiation treatment and / or ozone treatment. Patent CN102463112A discloses a hydrogenation catalyst for unsaturated carboxylic acid esters and a preparation method thereof, wherein the method is selected from at least one of palladium, ruthenium or rhodium in an amount of 0.2-1.0 parts; the amount of at least one of alkali metal oxides or alkaline earth metal oxides is selected to be 4.6-23.0 parts; the amount of at least one of silicon oxide or aluminum oxide is selected to be 76.0-95.0 parts, and the components of the catalyst used in the method and its preparation process are very complicated, which is not conducive to industrial application. Moreover, the reaction temperature reported in the patent is relatively high, which easily causes the reactants to coke on the catalyst surface, resulting in the deactivation of the eggshell catalyst. At present, there is no report on the systematic research on the catalyst, system and method for preparing n-propyl acetate and n-propanol from propylene and acetic acid. In order to solve the above problems, those skilled in the art are in urgent need of developing a method for synthesizing n-propyl acetate with high production efficiency and low cost to meet the existing market demand and performance requirements. Summary of the invention

[0007] The purpose of the present invention is to provide a catalyst, system and method for preparing n-propyl acetate and n-propanol from propylene and acetic acid in order to overcome the defects of the above-mentioned prior art. The present invention uses propylene and acetic acid as raw materials, prepares allyl acetate by oxyacetylation of propylene and acetic acid, hydrogenates allyl acetate to generate n-propyl acetate, and transesterifies n-propyl acetate with methanol to prepare n-propanol. The process has low raw material cost, high catalyst activity and good stability. The whole process adopts a fixed bed reactor, has high reaction efficiency, is simple in subsequent separation and purification, has high product purity, and has a high degree of production continuity, and is suitable for large-scale production.

[0008] The purpose of the present invention can be achieved by the following technical solutions:

[0009] The first object of the present invention is to provide a method for preparing n-propyl acetate and n-propanol from propylene and acetic acid, the method comprising the following steps: fresh acetic acid and propylene enter an acetic acid evaporator for mixed preheating to obtain a mixed preheated material, the mixed preheated material enters an oxygen mixing tank, oxygen is introduced into the oxygen mixing tank to obtain a mixed reaction material, the mixed reaction material enters an allyl acetate synthesis reactor, the allyl acetate synthesis reactor comprises an oxyacetylation catalyst, propylene and acetic acid undergo an oxyacetylation reaction under the action of the oxyacetylation catalyst to obtain a reacted material, and the reacted material The material enters the gas-liquid separation tower after heat exchange in the heat exchanger. The material at the top of the gas-liquid separation tower is acid-washed, alkaline-washed and CO2-absorbed, then circulated back to the fresh propylene raw material pipeline and then returned to the acetic acid evaporator connected to the propylene raw material pipeline. The material at the bottom of the gas-liquid separation tower enters the light-removing tower to remove light components. The material after light components are removed is taken out from the bottom of the light-removing tower. The material after light components are removed enters the acetic acid separation tower. Acetic acid is taken out from the bottom of the acetic acid separation tower and returned to the acetic acid evaporator. The azeotrope of allyl acetate and water is taken out from the top of the acetic acid separation tower. After condensation and phase separation, the oil phase is sent to the membrane separator for dehydration to obtain dehydrated allyl acetate.

[0010] The dehydrated allyl acetate material enters a hydrogenation reactor, hydrogen is introduced into the hydrogenation reactor for hydrogenation reaction, and n-propyl acetate is generated under the action of a hydrogenation catalyst. The reacted material is taken out from the bottom of the hydrogenation reactor, and the reacted material enters a gas-liquid separator. Hydrogen is taken out from the top of the gas-liquid separator and circulated back to the hydrogenation reactor. The allyl acetate liquid phase product is taken out from the bottom of the gas-liquid separator, and the allyl acetate liquid phase product enters a hydrogenation light component removal tower. After the light components are removed, part of the n-propyl acetate is taken out as a product, and part of the n-propyl acetate enters a reactive distillation tower;

[0011] The reaction distillation tower includes an ester exchange catalyst. n-propyl acetate and methanol undergo an ester exchange reaction in the reaction distillation tower. Methyl acetate and n-propanol are generated under the action of the ester exchange catalyst. Pure n-propanol is obtained in the reactor of the reaction distillation tower. A mixture of methanol and methyl acetate is obtained at the top of the reaction distillation tower. The mixture of methanol and methyl acetate enters an extractive distillation tower to separate methanol and methyl acetate. High-purity methyl acetate is obtained at the top of the extractive distillation tower. A methanol-water mixture is obtained at the bottom of the extractive distillation tower. The methanol-water enters an alcohol-water separation tower. The methanol obtained at the top of the alcohol-water separation tower enters a membrane evaporator for dehydration, and then the methanol is circulated into the reaction distillation tower. The water obtained at the bottom of the alcohol-water separation tower is circulated back to the extractive distillation tower.

[0012] Furthermore, the oxyacetylation catalyst is a loaded PdSb nano bimetallic catalyst (palladium-antimony bimetallic loaded catalyst), the particle size of the PdSb nano bimetallic is less than 5nm, and the carrier is one or a mixture of several of SiO2, α-Al2O3, ZrO2, and TiO2.

[0013] Furthermore, the hydrogenation catalyst is a loaded Pd catalyst, the particle size of Pd is less than 5nm, and one or more of the second metals Cu, Co, Ni, Fe, Au, Sn are added as an auxiliary agent, and the carrier is a mixture of one or more of SiO2, α-Al2O3, ZrO2, TiO2.

[0014] Furthermore, the transesterification catalyst is Amberlyst-A21 alkaline ion exchange resin catalyst.

[0015] Furthermore, in the oxyacetylation catalyst of the oxyacetylation reaction, the loading amount of Pd is 0.1wt%-5.0wt%, and the atomic ratio of Pd to Sb is 10:1-1:1.

[0016] Furthermore, the final composition of the mixed reaction materials of the oxyacetylation reaction is propylene: acetic acid: oxygen: nitrogen = 35-45: 4-10: 3-8: 40-60, the oxyacetylation reaction pressure is 0.5-0.8 MPa, and the reaction temperature is 150-170°C.

[0017] Furthermore, the hydrogenation catalyst is a loaded Pd catalyst, the metal additive is one or more of Cu, Co, Ni, Fe, Au, and Sn, the Pd loading is 0.1wt%-5.0wt%, the metal additive addition amount is 0.01wt%-5.0wt%, and the carrier is a mixture of one or more of SiO2, α-Al2O3, ZrO2, and TiO2.

[0018] Furthermore, the temperature of the hydrogenation reaction is 60-120° C., the pressure is 0.5-6.0 MPa, and the molar ratio of hydrogen to allyl acetate is 5:1-500:1.

[0019] Furthermore, the temperature of the transesterification reaction is 60-120° C., the reaction pressure is normal pressure, and the molar ratio of methanol to n-propyl acetate is 1:1-20:1.

[0020] Furthermore, in the transesterification unit, the operating pressure of the reaction distillation tower is 0.1-0.3 MPa, methanol is fed from the lower part of the reaction distillation tower, and n-propyl acetate is fed from the upper part of the reaction distillation tower.

[0021] The second object of the present invention is to provide a series of catalysts for preparing n-propyl acetate and n-propanol from propylene and acetic acid, wherein the catalyst is used to realize a method for preparing n-propyl acetate and n-propanol from propylene and acetic acid, and the catalyst comprises an oxyacetylation catalyst, a hydrogenation catalyst, and an ester exchange catalyst;

[0022] Furthermore, the oxygen acetylation catalyst is a PdSb loaded nano bimetallic catalyst, the particle size of the nano bimetallic is less than 5nm, the loading amount of Pd is 0.1wt%-5.0wt%, the atomic ratio of Pd and Sb is 10:1-1:1, and the carrier is one or a mixture of several of SiO2, α-Al2O3, ZrO2, and TiO2. When the particle size of Pd is less than 5nm, Pd has a higher catalytic activity, and the addition of Sb can effectively inhibit the over-oxidation of propylene and acetic acid, thereby improving the yield of allyl acetate.

[0023] Furthermore, the hydrogenation catalyst is a loaded Pd catalyst, the particle size of Pd is less than 5nm, and one or more of the second metals Cu, Co, Ni, Fe, Au, Sn are added as additives, the carrier is a mixture of one or more of SiO2, α-Al2O3, ZrO2, TiO2, and the amount of metal additive added is 0.01wt%-5.0wt%; the Pd catalyst has high selectivity for C=C double bonds, and Pd with a small particle size has higher hydrogenation activity. The addition of the second metal additive can effectively improve the activity and selectivity of C=C hydrogenation.

[0024] Furthermore, the transesterification catalyst is an Amberlyst-A21 alkaline ion exchange resin catalyst. Using an ion exchange resin as a transesterification catalyst can not only avoid the problem of difficulty in separating the catalyst and the product, but also avoid other side reactions caused by the catalyst.

[0025] The third object of the present invention is to provide a system for preparing n-propyl acetate and n-propyl alcohol from propylene and acetic acid, wherein the system is used to realize a method for preparing n-propyl acetate and n-propyl alcohol from propylene and acetic acid, and the system comprises an acetic acid evaporator, an oxygen mixing tank, an allyl acetate synthesis reactor, a heat exchanger, a gas-liquid separation tower, a light removal tower, an acetic acid separation tower, a membrane separator, a hydrogenation reactor, a gas-liquid separator, a hydrogenation light removal tower, a reactive distillation tower, an extractive distillation tower, an alcohol-water separation tower, and a membrane filter;

[0026] Further, the acetic acid evaporator is connected to an oxygen mixing tank; the oxygen mixing tank is connected to an allyl acetate synthesis reactor; the allyl acetate synthesis reactor is connected to a heat exchanger; the heat exchanger is connected to a gas-liquid separation tower; the top of the gas-liquid separation tower is connected to the acetic acid evaporator; the bottom of the gas-liquid separation tower is connected to a light removal tower; the light removal tower is connected to an acetic acid separation tower; the top of the acetic acid separation tower is connected to a membrane separator; the bottom of the acetic acid separation tower is connected to the acetic acid evaporator; the membrane separator is connected to a hydrogenation reactor; the hydrogenation reactor is connected to a gas-liquid separator; the gas-liquid separator is connected to a hydrogenation light removal tower; the hydrogenation light removal tower is connected to a reactive distillation tower; the top of the reactive distillation tower is connected to an extractive distillation tower; the bottom of the extractive distillation tower is connected to an alcohol-water separation tower; the bottom of the alcohol-water separation tower is connected to an extractive distillation tower; the top of the alcohol-water separation tower is connected to a membrane filter; the membrane filter is connected to a reactive distillation tower.

[0027] The present invention relates to a catalyst, system and method for preparing n-propyl acetate and n-propanol from propylene and acetic acid, which specifically comprises the following steps: propylene, acetic acid and oxygen undergo oxygen acetylation reaction under the action of palladium-antimony bimetallic supported catalyst to generate allyl acetate; after separation and purification, allyl acetate enters a hydrogenation reactor, hydrogenates under the action of Pd catalyst to generate n-propyl acetate, after hydrogen is separated by a gas-liquid separator, n-propyl acetate enters a reaction distillation tower, under the action of alkaline ion exchange resin, n-propyl acetate and methanol undergo ester exchange reaction to generate n-propanol and methyl acetate, and methyl acetate and n-propanol are obtained after separation and purification. Compared with the prior art, the present invention uses propylene and acetic acid as raw materials, and finally can obtain high value-added n-propyl acetate and n-propanol products, with good atom economy, low raw material cost, high catalyst activity, good stability, simple and efficient process, high degree of production continuity, simple subsequent separation and purification, high product purity, and is suitable for large-scale production.

[0028] Compared with the prior art, the present invention has the following beneficial effects:

[0029] 1) The present invention provides a catalyst, system and method for preparing n-propyl acetate and n-propyl alcohol from propylene and acetic acid, wherein the catalysts are all heterogeneous catalysts, the catalyst and product separation is simple, and the catalyst activity is high and the stability is good. The hydrogenation catalyst is a Pd catalyst, the reactants can be completely converted, and the separation problem of allyl acetate and n-propyl acetate is avoided. The transesterification reaction process of n-propyl acetate and methanol adopts a reactive distillation method, so that n-propyl acetate is completely converted, and the separation problem of n-propyl acetate and n-propyl alcohol is avoided.

[0030] 2) The present invention provides a catalyst, system and method for preparing n-propyl acetate and n-propanol from propylene and acetic acid. The method for preparing n-propyl acetate and n-propanol from propylene and acetic acid uses propylene and acetic acid as raw materials, and the reaction has good atom economy.

[0031] 3) The present invention provides a catalyst, system and method for preparing n-propyl acetate and n-propanol from propylene and acetic acid, which is a complete process for preparing n-propyl acetate and n-propanol from propylene and acetic acid. Propylene and acetic acid raw materials are subjected to oxyacetylation, hydrogenation and ester exchange reactions to obtain high-purity n-propyl acetate and n-propanol. The reaction efficiency is high, the production is continuous, the subsequent separation and purification is simple, the product purity is high, it is safe and reliable, the production cost is low, and it is suitable for large-scale production. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 Schematic diagram of a system for preparing n-propyl acetate and n-propanol from propylene and acetic acid in an embodiment of the present invention.

[0033] in:

[0034] V101-acetic acid evaporator, V102-oxygen mixing tank, R101-allyl acetate synthesis reactor, V103-heat exchanger, T101-gas-liquid separation tower, T102-light removal tower, T103-acetic acid separation tower, V104-membrane separator, R201-hydrogenation reactor, V201-gas-liquid separator, T201-hydrogenation light removal tower, R301-reaction distillation tower, T301-extraction distillation tower, T302-alcohol-water separation tower. DETAILED DESCRIPTION

[0035] The present invention is described in detail below in conjunction with specific embodiments, which are only used to illustrate the present invention and are not used to limit the scope of protection of the present invention. The features such as component models, material names, connection structures, control methods, etc. that are not clearly described in this technical solution are regarded as common technical features disclosed in the prior art.

[0036] like Figure 1As shown, the present invention provides a system for realizing a method for preparing n-propyl acetate and n-propanol from propylene and acetic acid, the system comprising an acetic acid evaporator V101, an oxygen mixing tank V102, an allyl acetate synthesis reactor R101, a heat exchanger V103, a gas-liquid separation tower T101, a light removal tower T102, an acetic acid separation tower T103, a membrane separator V104, a hydrogenation reactor R201, a gas-liquid separator V201, a hydrogenation light removal tower T201, a reactive distillation tower R301, an extractive distillation tower T301, and an alcohol-water separation tower T303;

[0037] Further, the acetic acid evaporator V101 is connected to the oxygen mixing tank V102; the oxygen mixing tank V102 is connected to the allyl acetate synthesis reactor R101; the allyl acetate synthesis reactor R101 is connected to the heat exchanger V103; the heat exchanger V103 is connected to the gas-liquid separation tower T101; the top of the gas-liquid separation tower T101 is connected to the acetic acid evaporator V101; the bottom of the gas-liquid separation tower T101 is connected to the light removal tower T102; the light removal tower T102 is connected to the acetic acid separation tower T103; the top of the acetic acid separation tower T103 is connected to the membrane separator V104; the bottom of the acetic acid separation tower T103 is connected to the acetic acid evaporator V101 01 is connected; the membrane separator V104 is connected to the hydrogenation reactor R201; the hydrogenation reactor R201 is connected to the gas-liquid separator V201; the gas-liquid separator V201 is connected to the hydrogenation delightening tower T201; the hydrogenation delightening tower T201 is connected to the reaction distillation tower R301; the top of the reaction distillation tower R301 is connected to the extractive distillation tower T301; the bottom of the extractive distillation tower T301 is connected to the alcohol-water separation tower T302; the bottom of the alcohol-water separation tower T302 is connected to the extractive distillation tower T301; the top of the alcohol-water separation tower T302 is connected to the membrane filter V301; the membrane filter V301 is connected to the reaction distillation tower R301.

[0038] Example

[0039] refer to Figure 1The present invention provides a catalyst and method for preparing n-propyl acetate and n-propanol from propylene and acetic acid. Fresh acetic acid and propylene enter an acetic acid evaporator V101 for mixing and preheating to obtain a mixed and preheated material. The mixed and preheated material enters an oxygen mixing tank V102. Oxygen is introduced into the oxygen mixing tank V102 to obtain a mixed reaction material. The mixed reaction material enters an allyl acetate synthesis reactor R101. The allyl acetate synthesis reactor R101 includes an oxygen acetylation catalyst. Propylene and acetic acid undergo an oxygen acetylation reaction under the action of the oxygen acetylation catalyst to obtain a reacted material. The reacted material is taken out from the bottom of the allyl acetate synthesis reactor R101. The reacted material is heat exchanged. After heat exchange in the reactor V103, the gas-liquid separation tower T101 is entered. The material at the top of the gas-liquid separation tower T101 is acid-washed, alkaline-washed and CO2-absorbed, and then circulated back to the fresh propylene raw material pipeline and then returned to the acetic acid evaporator V101 connected to the propylene raw material pipeline. The material at the bottom of the gas-liquid separation tower T101 enters the light-removal tower T102 to remove light components. The material after light components are removed is taken out from the bottom of the light-removal tower T102. The material after light components are removed enters the acetic acid separation tower T103. Acetic acid is taken out from the bottom of the acetic acid separation tower T103 and returned to the acetic acid evaporator V101. The azeotrope of allyl acetate and water is taken out from the top of the acetic acid separation tower T103. After condensation and phase separation, the oil phase is sent to the membrane separator V104 for dehydration to obtain dehydrated allyl acetate.

[0040] The dehydrated allyl acetate material enters the hydrogenation reactor R201, hydrogen is introduced into the hydrogenation reactor R201 for hydrogenation reaction, and n-propyl acetate is generated under the action of the hydrogenation catalyst. The reacted material is taken out from the bottom of the hydrogenation reactor R201, and the reacted material enters the gas-liquid separator V201. Hydrogen is taken out from the top of the gas-liquid separator V201 and circulated back to the hydrogenation reactor R201. The allyl acetate liquid phase product is taken out from the bottom of the gas-liquid separator V201, and the allyl acetate liquid phase product enters the hydrogenation light component removal tower T201. After the light components are removed, part of the n-propyl acetate is taken out as a product, and part of the n-propyl acetate enters the reactive distillation tower R301;

[0041] The reaction distillation tower R301 includes an ester exchange catalyst. n-propyl acetate and methanol undergo an ester exchange reaction in the reaction distillation tower R301, and methyl acetate and n-propanol are generated under the action of the ester exchange catalyst. Pure n-propanol is obtained at the bottom of the reaction distillation tower R301. A mixture of methanol and methyl acetate is obtained at the top of the reaction distillation tower R301. The mixture of methanol and methyl acetate enters the extractive distillation tower T301 to separate methanol and methyl acetate. High-purity methyl acetate is obtained at the top of the extractive distillation tower T301. A methanol-water mixture is obtained at the bottom of the extractive distillation tower T301. The methanol-water enters the alcohol-water separation tower T302. The methanol obtained at the top of the alcohol-water separation tower T302 enters the membrane evaporator V301 for dehydration, and then the methanol is circulated into the reaction distillation tower R301. The water obtained at the bottom of the alcohol-water separation tower T302 is circulated back to the extractive distillation tower T301.

[0042] In one embodiment of the present invention, an oil-water phase separator is provided between the acetic acid separation tower T103 and the membrane separator V104 to separate the liquid of the azeotropic mixture of allyl acetate and water extracted from the top condenser of the acetic acid separation tower T103, and the oil phase after separation is sent to the membrane separator V104 for dehydration.

[0043] In one embodiment of the present invention, the oxyacetylation catalyst is a loaded PdSb / TiO2 nano bimetallic catalyst, the particle size of the PdSb nano bimetallic is 4 nm, the loading amount of Pd is 1.0%, and the atomic ratio of Pd to Sb is 7:1;

[0044] In one embodiment of the present invention, the hydrogenation catalyst is a loaded PdAu / SiO2 catalyst, the loaded amount of Pd is 0.3%, the content of Au is 0.05%, and the particle size of PdAu is 3 nm.

[0045] In one embodiment of the present invention, the transesterification catalyst is Amberlyst-A21 alkaline ion exchange resin catalyst.

[0046] In one embodiment of the present invention, the final composition of the mixed reaction materials (i.e., reaction raw materials) of the oxyacetylation reaction is propylene: acetic acid: oxygen: nitrogen = 40: 11.5: 4.5: 44, the oxyacetylation reaction pressure is 0.8 MPa, the reaction temperature is 155°C, and the gas volume space velocity is 4000 h -1 .

[0047] In one embodiment of the present invention, the temperature of the hydrogenation reaction is 70°C, the pressure is 0.7 MPa, the molar ratio of hydrogen to allyl acetate is 100:1, the hydrogen flow rate is 100 mL / min, the mass space velocity of allyl acetate is 0.5 h -1 .

[0048] In one embodiment of the present invention, the temperature of the transesterification reaction is 80°C, the reaction pressure is atmospheric pressure, the molar ratio of methanol to n-propyl acetate is 10:1, and the mass space velocity of n-propyl acetate is 1.0 h -1 .

[0049] Under the above conditions, the ratio of the two products, n-propyl acetate and n-propanol, can be adjusted arbitrarily, wherein the purity of the n-propyl acetate product is 99.9%.

[0050] Under the above conditions, when the n-propyl acetate generated by the hydrogenation reaction of acetic acid is used for the transesterification reaction to produce n-propanol, the yield of n-propanol obtained from propylene is 95% and the purity is 99.9%.

[0051] The above description of the embodiments is to facilitate the understanding and use of the invention by those skilled in the art. It is obvious that those skilled in the art can easily make various modifications to these embodiments and apply the general principles described herein to other embodiments without creative work. Therefore, the present invention is not limited to the above embodiments, and improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the present invention should be within the scope of protection of the present invention.

Claims

1. A method for preparing n-propyl acetate and n-propanol from propylene and acetic acid, characterized in that: The method comprises the following steps: Acetic acid and propylene enter an acetic acid evaporator (V101) for mixed preheating to obtain a mixed preheated material. The mixed preheated material enters an oxygen mixing tank (V102). Oxygen is introduced into the oxygen mixing tank (V102) to obtain a mixed reaction material. The mixed reaction material enters an allyl acetate synthesis reactor (R101). The allyl acetate synthesis reactor (R101) includes an oxyacetylation catalyst. Propylene and acetic acid undergo an oxyacetylation reaction under the action of the oxyacetylation catalyst to obtain a reacted material. The reacted material enters a gas-liquid separation tower (T101) after heat exchange in a heat exchanger (V103). The gas-liquid separation tower (T101) The material at the top of the tower 101 is acid-washed, alkaline-washed and CO2-absorbed, and then circulated back to the acetic acid evaporator (V101); the material at the bottom of the gas-liquid separation tower (T101) enters the light-removing tower (T102) to remove light components; the material after light components are removed is taken out from the bottom of the light-removing tower (T102); the material after light components are removed enters the acetic acid separation tower (T103); acetic acid is taken out from the bottom of the acetic acid separation tower (T103) and returned to the acetic acid evaporator (V101); the azeotrope of allyl acetate and water is taken out from the top of the acetic acid separation tower (T103); after condensation and phase separation, the oil phase is sent to the membrane separator (V104) for dehydration to obtain dehydrated allyl acetate; The dehydrated allyl acetate material enters the hydrogenation reactor (R201), hydrogen is introduced into the hydrogenation reactor (R201) for hydrogenation reaction, and n-propyl acetate is generated under the action of a hydrogenation catalyst. The reacted material is extracted from the bottom of the hydrogenation reactor (R201), and the reacted material enters the gas-liquid separator (V201). Hydrogen is extracted from the top of the gas-liquid separator (V201) and circulated back to the hydrogenation reactor (R201). The allyl acetate liquid phase product is extracted from the bottom of the gas-liquid separator (V201), and the allyl acetate liquid phase product enters the hydrogenation light component removal tower (T201). After the light components are removed, part of the n-propyl acetate is extracted as a product, and part of the n-propyl acetate enters the reactive distillation tower (R301); The reaction distillation tower (R301) includes an ester exchange catalyst. n-propyl acetate and methanol undergo an ester exchange reaction in the reaction distillation tower (R301), and methyl acetate and n-propanol are generated under the action of the ester exchange catalyst. Pure n-propanol is obtained in the bottom of the reaction distillation tower (R301), and a mixture of methanol and methyl acetate is obtained at the top of the reaction distillation tower (R301). The mixture of methanol and methyl acetate enters the extractive distillation tower (T301) for separation of methanol and methyl acetate. Separation, high-purity methyl acetate is obtained at the top of the extractive distillation tower (T301), a methanol-water mixture is obtained at the bottom of the extractive distillation tower (T301), the methanol-water enters the alcohol-water separation tower (T302), the methanol obtained at the top of the alcohol-water separation tower (T302) enters the membrane evaporator (V301) for dehydration, and the methanol is circulated into the reactive distillation tower (R301), and the water obtained at the bottom of the alcohol-water separation tower (T302) is circulated back to the extractive distillation tower (T301); The oxyacetylation catalyst is a loaded PdSb nano bimetallic catalyst; The hydrogenation catalyst is a supported Pd catalyst; The transesterification catalyst is a basic ion exchange resin catalyst.

2. The method for preparing n-propyl acetate and n-propanol from propylene and acetic acid according to claim 1, characterized in that: The oxyacetylation catalyst is a PdSb nano bimetallic catalyst, the particle size of the PdSb nano bimetallic catalyst is less than 5nm, and the carrier is one or a mixture of SiO2, α-Al2O3, ZrO2, and TiO2; The hydrogenation catalyst is a loaded Pd catalyst, the particle size of Pd is less than 5nm, and one or more of the second metals Cu, Co, Ni, Fe, Au, Sn are added as an auxiliary agent, and the carrier is one or a mixture of SiO2, α-Al2O3, ZrO2, TiO2; The transesterification catalyst is Amberlyst-A21 alkaline ion exchange resin catalyst.

3. A method for preparing n-propyl acetate and n-propanol from propylene and acetic acid according to claim 2, characterized in that: In the oxyacetylation catalyst, the loading amount of Pd is 0.1wt%-5.0wt%, and the atomic ratio of Pd to Sb is 10:1-1:

1.

4. The method for preparing n-propyl acetate and n-propanol from propylene and acetic acid according to claim 2, characterized in that: In the hydrogenation catalyst, the loading amount of Pd is 0.1wt%-5.0wt%.

5. The method for preparing n-propyl acetate and n-propanol from propylene and acetic acid according to claim 1, characterized in that: The composition of the mixed reaction materials of the oxyacetylation reaction is propylene: acetic acid: oxygen: nitrogen = 35-45: 4-10: 3-8: 40-60, the oxyacetylation reaction pressure is 0.5-0.8 MPa, and the reaction temperature is 150-170°C.

6. The method for preparing n-propyl acetate and n-propanol from propylene and acetic acid according to claim 1, characterized in that: The temperature of the hydrogenation reaction is 60-120° C., the pressure is 0.5-6.0 MPa, and the molar ratio of hydrogen to allyl acetate is 5:1-500:

1.

7. The method for preparing n-propyl acetate and n-propanol from propylene and acetic acid according to claim 1, characterized in that: The temperature of the transesterification reaction is 60-120° C., the reaction pressure is normal pressure, and the molar ratio of methanol to n-propyl acetate is 1:1-20:

1.

8. The method for preparing n-propyl acetate and n-propanol from propylene and acetic acid according to claim 1, characterized in that: The operating pressure of the reaction distillation tower (R301) is 0.1-0.3 MPa, methanol is fed from the lower part of the reaction distillation tower (R301), and n-propyl acetate is fed from the upper part of the reaction distillation tower (R301).

9. A system for implementing the method for preparing n-propyl acetate and n-propanol from propylene and acetic acid as claimed in any one of claims 1 to 8, characterized in that: The system comprises an acetic acid evaporator (V101), an oxygen mixing tank (V102), an allyl acetate synthesis reactor (R101), a heat exchanger (V103), a gas-liquid separation tower (T101), a light removal tower (T102), an acetic acid separation tower (T103), a membrane separator (V104), a hydrogenation reactor (R201), a gas-liquid separator (V201), a hydrogenation light removal tower (T201), a reactive distillation tower (R301), an extractive distillation tower (T301), an alcohol-water separation tower (T303), and a membrane filter (V301); The acetic acid evaporator (V101) is connected to the oxygen mixing tank (V102); The oxygen mixing tank (V102) is connected to the allyl acetate synthesis reactor (R101); The allyl acetate synthesis reactor (R101) is connected to a heat exchanger (V103); The heat exchanger (V103) is connected to the gas-liquid separation tower (T101); The top of the gas-liquid separation tower (T101) is connected to the acetic acid evaporator (V101); The bottom of the gas-liquid separation tower (T101) is connected to the lightness removal tower (T102); The lightness removal tower (T102) is connected to the acetic acid separation tower (T103); The top of the acetic acid separation tower (T103) is connected to a membrane separator (V104); The bottom of the acetic acid separation tower (T103) is connected to the acetic acid evaporator (V101); The membrane separator (V104) is connected to the hydrogenation reactor (R201); The hydrogenation reactor (R201) is connected to a gas-liquid separator (V201); The gas-liquid separator (V201) is connected to the hydrogenation light removal tower (T201); The hydro-removal tower (T201) is connected to the reactive distillation tower (R301); The top of the reactive distillation tower (R301) is connected to the extractive distillation tower (T301); The bottom of the extractive distillation tower (T301) is connected to the alcohol-water separation tower (T302); The bottom of the alcohol-water separation tower (T302) is connected to the extractive distillation tower (T301); The top of the alcohol-water separation tower (T302) is connected to a membrane filter (V301); The membrane filter (V301) is connected to the reactive distillation tower (R301).

10. A catalyst for realizing the method for preparing n-propyl acetate and n-propanol from propylene and acetic acid as claimed in any one of claims 1 to 8, characterized in that: The catalyst includes an oxyacetylation catalyst, a hydrogenation catalyst, and an ester exchange catalyst; The oxygen acetylation catalyst is in the allyl acetate synthesis reactor (R101); The hydrogenation catalyst is in the hydrogenation reactor (R201); The transesterification catalyst is in the reactive distillation tower (R301).

Images