CN103664529B - Method for coproducing cyclohexanol and ethanol - Google Patents

Abstract

The invention relates to a method for co-producing cyclohexanol and ethanol. In the method, reactive distillation is used to carry out the addition esterification reaction of acetic acid and cyclohexene to prepare cyclohexyl acetate; then, cyclohexyl acetate is hydrogenated to co-produce cyclohexanol and ethanol. The method of the invention can produce cyclohexanol with high efficiency and low cost and co-produce ethanol.

Description

Method for coproducing cyclohexanol and ethanol

technical field

The present invention relates to a method for the coproduction of cyclohexanol and ethanol.

Background technique

Both cyclohexanol and ethanol are important chemical raw materials and solvents. Cyclohexanol is mainly used to produce nylon 6, nylon 66, etc., while ethanol is a raw material for synthetic esters and other chemical products, and is also widely used as a fuel additive for gasoline.

The method of industrially synthesizing ethanol is mainly the direct hydration method of ethylene, but in some countries rich in agricultural and sideline products, the fermentation method is still the main method of ethanol production. Due to the large population and insufficient arable land in our country, and the problem of "competing with the mouth for food" in the production of ethanol by fermentation, the fermentation method does not conform to the national conditions of our country. In addition, the pollution of the fermentation method is also relatively serious. my country's oil resources are relatively insufficient, and the price of ethylene is greatly affected by fluctuations in international oil prices. Therefore, the application of ethylene hydration in my country will face certain pressure on raw material costs. In addition, the reaction conditions of the ethylene direct hydration method are relatively harsh and need to be carried out under high temperature and high pressure. In summary, the development of new ethanol synthesis process routes is an inevitable requirement for technological and economic development.

CN1022228831A discloses a catalyst for preparing ethanol by gas-phase hydrogenation of acetic acid. The catalyst is composed of three parts: main active component, auxiliary agent and carrier; the carrier is any one of activated carbon, graphite or multi-walled carbon nanotubes, and the main active The component is any one or two of metal W or Mo, and the auxiliary agent is one or more of Pd, Re, Pt, Rh or Ru; the content of the main active component is 0.1-30.0% of the weight of the catalyst, and the auxiliary agent is The content of the agent is 0.1-10.0% of the weight of the catalyst, and the balance is the carrier.

CN102149661A discloses a method for the direct and selective production of ethanol from acetic acid using a platinum/tin catalyst, comprising: a feed stream containing acetic acid and hydrogen is contacted with a hydrogenation catalyst at a relatively high temperature, and the hydrogenation catalyst is included in a suitable The group of platinum and tin on the catalyst support and optionally a third metal supported on the support, wherein the third metal is selected from the group consisting of the following metals: palladium, rhodium, ruthenium, rhenium. Iridium, Chromium, Copper, Molybdenum, Tungsten, Vanadium and Zinc.

Industrially, the production methods of cyclohexanol mainly include cyclohexane air oxidation method, phenol hydrogenation method and cyclohexene hydration method, among which cyclohexane oxidation method is the most common application.

Cyclohexane oxidation is currently the most important cyclohexanol production process. The process uses an oxidant (usually air) to oxidize cyclohexane to cyclohexyl hydroperoxide, and cyclohexyl hydroperoxide is decomposed to obtain a mixture of cyclohexanol and cyclohexanone (commonly known as KA oil). The advantages of this process are mild oxidation process conditions, less slagging, and long continuous operation period. The disadvantage is that the process route is long, the energy consumption is high, and the pollution is large. The conversion rate of cyclohexane in this process is only 3-5%; especially in the decomposition process of cyclohexyl hydroperoxide, the selectivity of cyclohexanol is poor, and the yield In addition, this process also produces a large amount of waste lye that is difficult to handle, which is still a worldwide environmental protection problem.

Phenol hydrogenation is a relatively clean technical route for the production of cyclohexanol, and has the advantages of short process flow and high product purity. The hydrogenation of phenol to cyclohexanol mainly adopts the gas phase hydrogenation method. This method usually adopts 3 to 5 reactors connected in series. Under the action of supported Pd catalyst, the yield of cyclohexanone and cyclohexanol can reach 90%-95% at 140-170°C and 0.1MPa. However, this process needs to vaporize phenol (heat of vaporization 69kJ·mol ^-1 ) and methanol (heat of vaporization 35.2kJ·mol ^-1 ), which requires high energy consumption, and the catalyst is prone to carbon deposition during use, resulting in a decrease in activity, and the shortage of phenol , expensive and the use of noble metal catalysts limit the industrial application of this method.

In the 1980s, Asahi Kasei Corporation of Japan developed a process for producing cyclohexene by partial hydrogenation of benzene and hydration of cyclohexene to produce cyclohexanol, and realized industrialization in 1990. Related Chinese patent applications include CN1079727A, CN1414933A and CN101796001A . Cyclohexene hydration is a relatively new production method of cyclohexanol. This method has high reaction selectivity and almost no three wastes in the process. However, there are disadvantages such as low reaction conversion rate and high requirements for cyclohexene purity. If high silicon ZSM-5 catalyst is used, the conversion rate of cyclohexene is only 12.5% after staying in two series slurry reactors for 2 hours.

CN86105765A proposes a method for preparing alcohol by hydrogenation of carboxylic acid ester, which method is to hydrogenate carboxylic acid ester at high temperature, normal pressure or high pressure in the presence of a reduction-activated solid copper-containing catalyst, and the catalyst removes copper In addition, it also contains magnesium, at least one of lanthanide metals or actinide metals. The catalyst is represented by the following general formula before reduction activation: Cu _a M ¹ M ² _b A _c O _x , M ¹ is at least one of magnesium, lanthanide metal or actinide metal, M ² is selected from Ca, Mo, Rh , Pt, Cr, Zn, Al, Ti, V, Ru, Re, Pd, Ag and Au; A is an alkali metal; a is 0.1-4; b is 0-1.0; C is 0-0.5; x is A number that can meet the requirements of other elements for the total valence of oxygen. The alkali metal in the catalyst is an optional component which is introduced into the catalyst in the form of an alkali metal salt. The applicable carboxylate of this method and catalyst is C1～C24 acyclic monovalent or divalent, saturated or unsaturated, straight chain or branched chain carboxylate, does not relate to the production of cycloalkanol like cyclohexanol.

CN1075048C proposes a method and catalyst for direct hydrogenation of carboxylic acid esters, comprising contacting and reacting one or more esters with hydrogen in the presence of a catalyst containing a copper compound, a zinc compound and at least one selected The catalyst is prepared from aluminum, zirconium, magnesium, a compound of a rare earth element or a mixture thereof as its components by calcining these catalyst components at a temperature ranging from 200 to less than 400°C, the method being in a liquid phase , Carried out at 170-250°C and 20.7-138 bar gauge pressure. The applicable carboxylic acid ester of this method and catalyst is the C6～C22 dimethyl ester obtained by the transesterification of natural oil, the C6～C66 natural triglyceride or the C6～C44 compound that is obtained by the transesterification of natural triglyceride .

US4939307 proposes a process for ester hydrogenation to alcohol. The general formula is R ₁ -CO-OR ₂ or R ₄ O-CO-R ₃ -CO-OR ₂ (wherein R ₁ is H or C ₁ ~ C ₂₀ hydrocarbon group, R ₂ and R ₄ are C ₁ ~ C ₂₀ Hydrocarbon group, R ₃ is -(CH ₂ )n-group, n=1~10) ester with H ₂ and CO mixed gas, hydrogenation reaction at 30~150°C, 5~100 bar pressure to generate alcohol, The catalyst is composed of the following components: (a) a metal ion compound of group VIII in the periodic table; (b) an alkoxide of an alkali metal or an alkaline earth metal; (c) an alcohol.

US4113662 and USP4149021 disclose a kind of ester hydrogenation catalyst, and this catalyst is made up of the element of cobalt, zinc, copper, oxide, hydroxide or carbonate, and the most suitable carboxylate of this catalyst is polyglycolide, The preparation of cycloalkanols is not mentioned in the literature.

US4611085 discloses a method for gas-phase hydrogenation of C ₁ -C ₂₀ carboxylic acid esters to produce alcohols, which is characterized in that the catalyst is composed of a VIII group element, an auxiliary agent and a carbon carrier, wherein the VIII group element includes Ru , Ni, Rh, additives include IA (except Li), group IIA (except Be and Mg), lanthanides and actinides, and the BET specific surface area of the carbon support is greater than 100m ² /g. The hydrogenation reaction is carried out under the conditions of 100-400°C and gas space velocity of 100-120000h ^-1 . The alkali metals in the catalyst are introduced in the form of alkali metal salts, such as alkali metal nitrates, carbonates or acetates. The method is applicable to carboxylic acid esters that can be vaporized under reaction conditions. The carbon number of the alcohol-derived moiety in the carboxylic acid esters is preferably less than 5 and the carbon connected to oxygen is preferably a primary carbon.

GB2250287A discloses a method for hydrogenating fatty acid esters to produce alcohols. The method is characterized in that a copper-containing catalyst is used for hydrogenation and a certain amount of water is added to the ester raw material to maintain the activity of the catalyst. The applicable carboxylate is C12-C18 fatty acid methyl ester.

US5334779 discloses a catalyst composition and its use in the hydrogenation of carboxylic acid esters. The catalyst consists of copper oxide, zinc oxide and a third component (oxides of aluminum, magnesium, zirconium or their mixtures). The carboxylic acid ester used in the catalyst and method is dimethyl cycloadipate, lower alkyl ester of C10-C20 carboxylic acid, dilower alkyl ester of adipic acid and dilower alkyl ester of maleic acid.

At present, the synthetic method of cyclohexyl acetate in industry is the esterification reaction of acetic acid and cyclohexanol. The alkyd esterification reaction needs to be carried out smoothly under the action of an acidic catalyst. Song Guijia, Wu Xionggang (Chemical Propellants and Polymer Materials, 2009, V0l.7(2):P31～33), reviewed the progress in the synthesis of cyclohexyl acetate from acetic acid and cyclohexanol esterification, and the catalysts involved Including sulfamic acid, p-toluenesulfonic acid and other sulfonic acid catalyst systems, SO ₄ ^2- /TiO ₂ , S ₂ O ₈ ^2- /ZnO ₂ -Fe ₂ O ₃ -SiO ₂ , S ₂ O ₈ ^2- /Fe ₂ O ₃ -MoO ₃ and other solid superacid catalyst systems, ferrous sulfate, sodium bisulfate, potassium hydrogen sulfate, ferric chloride, copper sulfate and other inorganic salt catalyst systems, phosphotungstic acid and supported heteropolyacid catalyst systems.

CN102060697 proposes a synthesis process of cyclohexyl acetate. First, copper oxide and p-toluenesulfonic acid are reacted to synthesize copper p-toluenesulfonate, then copper p-toluenesulfonate is used as a catalyst, and cyclohexane is used as a water-carrying agent. Acetic acid and cyclohexanol react to synthesize cyclohexyl acetate. Alkylate synthesis of cyclohexyl acetate has problems such as difficulty in separating the catalyst from the product, the need to use a water-carrying agent, and the high price of cyclohexanol, so it is difficult to produce on a large scale.

JPA254634/1989 discloses a preparation method of cyclohexanol and cyclohexyl acetate, using a strongly acidic ion exchange resin as a catalyst to synthesize cyclohexanol and cyclohexyl acetate by the reaction of aqueous acetic acid and cyclohexene. The best result mentioned in this patent example is that the conversion rate of cyclohexene is 62.7%, the yield of cyclohexanol is 18.4%, and the yield of cyclohexyl acetate is 43.7%.

CN1023115C, JP Ping-313447 discloses a preparation method of cyclohexanol, using ZSM5 or high silica zeolite as a catalyst and in the presence of water, to synthesize cyclohexyl acetate by reacting acetic acid and cyclohexene, reacting at 120°C for 4h, cyclohexanol The yields of hexanol and cyclohexyl acetate were only 12.5% and 65%, respectively.

EP0461580A2 and USP5254721 disclose a method of using a tungsten-containing heteropolyacid catalyst to react acetic acid and cyclohexene to prepare cyclohexyl acetate. This patent proposes that the crystal water content in the heteropolyacid molecule should preferably be 0-3. The best result given by the patent is that the dodecasilicate tungstic acid catalyst completely free of crystal water obtained by roasting at 370°C for 3 hours, in a 200mL autoclave, add 61.5g of acetic acid, 13.5g of cyclohexene, and 5g of catalyst. 0.5MPA, 130°C for 0.5h, the conversion rate of cyclohexene is 95.2%, and the selectivity of cyclohexyl acetate is 99.2%. It can be seen that under the condition of very high acid-to-ene ratio, cyclohexene cannot be completely converted. Since complete conversion of cyclohexene cannot be achieved, if the product stream of selective hydrogenation of benzene (a mixture of cyclohexene and benzene and cyclohexane) is used as the feedstock, the presence of cyclohexene with benzene and cyclohexane will inevitably occur Because the boiling points of benzene, cyclohexene and cyclohexane are very close, it is necessary to adopt the method of extractive distillation to separate, so the investment and operation costs of separation are very high.

Known from published literature, existing literature has disclosed the various solid acid catalysts of acetic acid and cyclohexene addition esterification reaction, and addition esterification reaction generally adopts kettle type reactor, and reaction raw material is pure cyclohexene, Even with a high acid-to-ene ratio, it is difficult to achieve complete conversion of cyclohexene.

Reactive distillation has been widely used in processes such as alcohol-ene etherification, alcohol esterification, transesterification, ester hydrolysis, acetal reaction, etc., but so far, no reactive distillation has been used for the addition and esterification of acetic acid and cyclohexene process reports.

So far, in the prior art, there is no information disclosure about the addition and esterification of cyclohexene and acetic acid, and then hydrogenation to co-produce cyclohexanol and ethanol, and there is no information about the hydrogenation of cyclohexyl acetate. Information disclosure on the production of cyclohexanol and ethanol.

Contents of the invention

The invention provides a method for the co-production of cyclohexanol and ethanol. The method first uses reactive distillation to carry out the addition esterification reaction of acetic acid and cyclohexene to prepare cyclohexyl acetate; and then hydrogenates cyclohexyl acetate to co-produce cyclohexanol and ethanol.

In the present invention, "addition esterification reaction" refers to a reaction in which a carboxylic acid is added to an olefin double bond to form an ester.

A method for the coproduction of cyclohexanol and ethanol, comprising:

(1) Input the acetic acid and cyclohexene raw materials into the reactive distillation tower, contact with the solid acid catalyst, react, and simultaneously separate the reaction product, and obtain cyclohexyl acetate from the bottom of the tower; the cyclohexene raw material is cyclohexyl Alkenes or mixtures of cyclohexene with cyclohexane and/or benzene;

(2) The cyclohexyl acetate obtained in step (1) enters the hydrogenation reactor and undergoes a hydrogenation reaction in the presence of an ester hydrogenation catalyst. The material after the hydrogenation reaction enters the hydrogenation product separation system for separation to obtain cyclohexyl acetate alcohol and ethanol.

The cyclohexene raw material is a mixture of cyclohexene, cyclohexane and/or benzene, and the cyclohexene content is preferably 20m%-80m%, more preferably 20m%-60m%. Industrially, cyclohexene is generally produced by selective hydrogenation of benzene, and the product stream is a mixture of cyclohexene, cyclohexane and benzene, and the content of cyclohexene is generally 20m% to 60m%. Extraction and separation can obtain streams whose cyclohexene content is generally 40m% to 80m%. The present invention preferably uses these streams as cyclohexene raw materials, which can avoid or simplify the separation process with high investment and operating costs.

The cyclohexene raw material is a mixture of cyclohexene, cyclohexane and/or benzene, and a mixture of acetic acid, cyclohexane and/or benzene is obtained from the top of the reactive distillation column.

The reactive distillation column is the same in form as an ordinary distillation column, and generally consists of a column body, a top condenser, a reflux tank, a reflux pump, a column kettle, and a reboiler. The type of column can be a tray column, a packed column, or a combination of both. The types of tray columns that can be used include valve columns, sieve tray columns, bubble cap columns, etc. The packing used in the packed tower can be random packing, such as Pall ring, θ ring, saddle packing, stepped ring packing, etc.; it can also be structured packing, such as corrugated plate packing, corrugated wire mesh packing, etc.

According to the method provided by the present invention, a solid acid catalyst is arranged in the reactive distillation column. Those skilled in the art know clearly that the catalyst arrangement in the reactive distillation column should meet the following two requirements: (1) It should be able to provide enough channels for the passage of vapor-liquid two-phase, or have a relatively large bed gap rate (generally at least 50%) to ensure that the gas-liquid two-phase can flow through without causing flooding; (2) to have good mass transfer performance, the reactant should be transferred from the fluid phase to the catalyst for reaction, At the same time, the reaction product is transferred from the catalyst. Various arrangements of catalysts in the reactive distillation column have been disclosed in the existing literature, and all of these arrangements can be adopted in the present invention. The arrangement of existing catalysts in the reaction tower can be divided into the following three types: (1) The catalyst is directly arranged in the tower in the form of rectification packing. The main method is to mechanically mix catalyst particles of a certain size and shape with rectification packing , or the catalyst is sandwiched between the structured packing and the structured packing to form an integral packing, or the catalyst is directly made into the shape of the rectification packing; (2) The catalyst is placed in a small gas-liquid permeable container and placed in the reaction The catalyst is placed on the tray of the tower, or the catalyst is arranged in the downcomer of the reaction tower; (3) The catalyst is directly loaded into the reaction tower in the form of a fixed bed, and the liquid phase flows directly through the catalyst bed layer, and a dedicated gas phase is set up. In this way, the catalyst bed and the rectification tray are alternately arranged at the position where the catalyst is installed. The liquid on the tray enters the next catalyst bed through the downcomer and the redistributor, and is carried out in the bed. Addition reaction, the liquid in the lower part of the catalyst bed enters the next tray through the liquid collector.

The reactive distillation column must have enough theoretical plate numbers and reaction plate numbers to meet the reaction and separation requirements. The theoretical plate number of the reactive distillation column is 10-150, preferably 30-100, and the solid acid catalyst is arranged between 1/3 to 2/3 of the theoretical plate number.

In the present invention, it is necessary to ensure that the reactants have sufficient residence time to realize the complete conversion of cyclohexene. Relative to the total loading volume of the catalyst, the liquid feed space velocity is 0.2-20h ^-1 , preferably 0.5-5h ^-1 .

In the present invention, the operating pressure of the reactive distillation column can be operated under negative pressure, normal pressure and pressurized conditions. The operating pressure of the reactive distillation tower is -0.0099MPa to 5MPa, preferably normal pressure to 1MPa.

The operating temperature of the reactive distillation tower is related to the pressure of the reactive distillation tower. The temperature distribution of the reaction tower can be adjusted by adjusting the operating pressure of the reaction tower so that the temperature of the catalyst loading area is within the active temperature range of the catalyst. The temperature of the catalyst loading area is between 50°C and 200°C, preferably between 60°C and 120°C.

The reflux ratio of the reactive distillation column should meet the requirements of separation and reaction at the same time. In general, increasing the reflux ratio is conducive to improving the separation ability and reaction conversion rate, but at the same time it will increase the energy consumption of the process.

In the present invention, if pure cyclohexene and acetic acid are used as reaction raw materials, total reflux can be realized theoretically. When there is a small amount of light component impurities in the reaction raw materials, it is necessary to lead a small amount of overhead stream out of the reactive distillation column. In the present invention, the reflux ratio is 0.1-100:1, preferably 0.5-10:1.

The solid acid catalyst can be selected from one or more of strong acid ion exchange resin catalysts, heteropolyacid catalysts and molecular sieve catalysts.

The strong acid ion exchange resin catalyst includes not only ordinary macroporous sulfonic acid polystyrene-divinylbenzene resin, but also sulfonic acid resin modified by halogen atoms. This kind of resin is easy to buy from the market, and can also be prepared according to the methods recorded in classic literature. The preparation method of macroporous sulfonic acid polystyrene-divinylbenzene resin is usually to drop the mixture of styrene and divinylbenzene into the water phase containing dispersant, initiator and porogen under the condition of high-speed stirring. Carry out suspension copolymerization in the system, separate the obtained polymer balls (white balls) from the system, use a solvent to remove the porogen, and then use dichloroethane as a solvent and concentrated sulfuric acid as a sulfonating agent to carry out Sulfonation reaction, and finally through filtration, washing and other processes, the final product is obtained. Introducing halogen atoms, such as fluorine, chlorine, bromine, etc., into the skeleton of ordinary strong acid ion exchange resin can further improve the temperature resistance and acid strength of the resin. This halogen-containing strongly acidic high-temperature resistant resin can be obtained at least through the following two ways. One way is to introduce a halogen atom, such as a chlorine atom, into the benzene ring of the sulfonated styrene resin skeleton. Due to the strong electron-withdrawing effect of the halogen element It can not only stabilize the benzene ring, but also increase the acidity of the sulfonic acid group on the benzene ring, so that the acid strength function (Hammett function) of the resin catalyst can be H0≤-8, and it can be used for a long time above 150°C. Resin can be easily purchased from the market, such as Amberlyst45 resin produced by foreign ROHM & HASS company, D008 resin produced by Hebei Jizhong Chemical Factory in China, etc.; another way is to replace all the hydrogen on the resin skeleton with fluorine, due to the strong absorption of fluorine Electronic properties make it super acidic and super high thermal stability, the acid strength function (Hammett function) H0 can be less than -12, and the heat resistance temperature can reach above 250 ℃, a typical example of this kind of high temperature resistant strong acid resin It is Nafion resin produced by DuPont Company.

The heteropolyacid catalyst can be heteropolyacid and/or heteropolyacid acid salt, or a catalyst supporting heteropolyacid and/or heteropolyacid acid salt. The acid strength function H0 of the heteropoly acid and its acid salt can be less than -13.15, and can be used for a long time up to 300°C. The heteropolyacid and its acid salt include Kegin structure, Dawson, Anderson structure, Silverton structure heteropoly acid and its acid salt. Heteropolyacids with keggin structure and their acid salts are preferred, such as dodecaphosphotungstic acid (H ₃ PW ₁₂ O ₄₀ ·xH ₂ O), dodecasilicatetungstic acid (H ₄ S iW ₁₂ O ₄₀ ·xH ₂ O) , dodecaphosphomolybdic acid (H ₃ PMo ₁₂ O ₄₀ ·xH ₂ O), dodecaphosphomolybdovanadic acid (H ₃ PMo _12- yV _y O ₄₀ ·xH ₂ O), etc. The heteropoly acid acid salt is preferably cesium phosphotungstate (Cs ₂₅ H _0.5 P ₁₂ WO ₄₀ ), whose acid strength function H0 is less than -13.15, and the specific surface area can reach more than 100 m ² /g. In the catalyst supporting heteropolyacid and/or heteropolyacid acid salt, the carrier is _SiO2 and/or activated carbon.

In the present invention, the solid acid catalyst can also be a molecular sieve catalyst. The molecular sieve can be one or more of Hβ, HY and HZSM-5, preferably one or more of Hβ, HY and HZSM-5 modified with fluorine or phosphorus. After these molecular sieves are modified by fluorine and phosphorus, the acidity and catalytic performance of the molecular sieve can be further improved.

Preferably, the number of theoretical plates of the reactive distillation column is 30 to 100, and a solid acid catalyst is arranged between 1/3 and 2/3 of the number of theoretical plates; the solid acid catalyst is high temperature resistant sulfur Acid-type ion exchange resin or acid-type cesium phosphotungstate; relative to the total loading volume of the catalyst, the liquid feed space velocity is 0.5-5h ^-1 ; the operating pressure of the reactive distillation tower is -0.0099MPa to 5MPa; the catalyst loading The temperature of the zone is between 120-180°C; the reflux ratio is 0.5-10:1.

According to the method provided by the present invention, the cyclohexyl acetate obtained from the bottom of the reactive distillation column is sent to an ester hydrogenation reactor for hydrogenation reaction. There are one or more ester hydrogenation reactors, and the reactor type is selected from one or more of tank reactors, fixed bed reactors, ebullating bed reactors and fluidized bed reactors. The fixed-bed reactor is preferably a tubular fixed-bed reactor, more preferably a shell-and-tube reactor.

Although the existing published literature is mainly about the hydrogenation of methyl carboxylate or ethyl carboxylate, as usual, hydrogenation of fatty acid methyl esters is used to produce higher alcohols, and methyl maleate is hydrogenated to produce 1, 4-butanediol, hydrogenation of dimethyl 1,6-hexanedioate to produce 1,6-hexanediol, etc., there is no hydrogenation of cyclohexyl acetate, a carboxylate derived from cycloalkanol The report of reaction, but the inventor finds, the hydrogenation of cyclohexyl acetate can adopt existing ester compound hydrogenation catalyst. The hydrogenation of esters generally uses copper-based catalysts, ruthenium-based catalysts and noble metal-based catalysts, with copper-based catalysts being the most commonly used. Copper-based ester hydrogenation catalysts use copper as the main catalyst, and add chromium, aluminum, zinc, calcium, magnesium, nickel, titanium, zirconium, tungsten, molybdenum, ruthenium, platinum, palladium, rhenium, lanthanum, thorium, gold, etc. One or more components are used as co-catalysts or additive components. Copper-based ester hydrogenation catalysts can be easily purchased from the market, and can also be prepared by co-precipitation. The usual preparation method is to put the soluble salt solution of each metal into the neutralization kettle, and add alkali solution (sodium hydroxide, sodium carbonate, ammonia water, urea, etc.) at a certain temperature and stirring speed to neutralize to pH8~ 12 Growth and precipitation, the precipitation is formed through aging, filtration, washing, drying, roasting, molding and other processes, and finally reduced in a hydrogen atmosphere to make the final ester hydrogenation catalyst. Ruthenium-based catalysts generally include: Ru/Al ₂ O ₃ or Ru-Sn/Al ₂ O ₃ ; noble metal-based catalysts generally include: Pt/Al ₂ O ₃ , Pd-Pt/Al ₂ O ₃ or Pd/C (the catalyst represents For: active ingredient/carrier).

In the present invention, the ester hydrogenation catalyst can be selected from one or more of copper-based catalysts, ruthenium-based catalysts and noble metal-based catalysts, preferably copper-based catalysts, more preferably zinc-containing copper-based catalysts and/or chromium-containing Copper-based catalysts.

The ester hydrogenation reaction can be operated in a batch mode or in a continuous mode. The batch reaction generally uses a reactor as a reactor, puts cyclohexyl acetate and a hydrogenation catalyst into the reactor, feeds hydrogen to react at a certain temperature and pressure, and discharges the reaction product from the reactor after the reaction is completed. , The product is separated, and then put into the next batch of materials for reaction. The continuous hydrogenation reaction can use shell-and-tube shell-and-tube reactors. The hydrogenation catalyst is fixed in the shell tubes, and the heat released by the reaction is removed by cooling water at the shell side.

The hydrogenation reaction temperature of cyclohexyl acetate is related to the selected hydrogenation catalyst. For copper-based hydrogenation catalysts, the general hydrogenation reaction temperature is 150-400°C, and the optimal reaction temperature is 200-300°C. The reaction pressure is from normal pressure to 20MPa, and the optimal pressure is from 4 to 10MPa.

The control of the hydrogen ester molar ratio in the cyclohexyl acetate hydrogenation reaction is also very important. A high hydrogen-to-ester ratio is beneficial to the hydrogenation of esters, but too high a hydrogen-to-ester ratio will increase the energy consumption of the hydrogen compression cycle. Generally, the ratio of hydrogen to ester is 1-1000:1, and the optimal condition is 5-100:1.

In the hydrogenation reaction, the feed space velocity of the ester is related to the activity of the selected catalyst. Higher activity catalysts can use higher space velocities. For the selected catalyst, the reaction conversion decreases with the increase of the reaction space velocity. In order to meet a certain conversion rate, the space velocity must be limited within a certain range. Generally, the liquid feeding space velocity of the ester is 0.1-20h ^-1 , and the optimum condition is 0.2-2h ^-1 . If a batch reaction is adopted, the reaction time is 0.5-20 h, preferably 1-5 h.

According to the method provided by the present invention, the cyclohexyl acetate hydrogenation product enters the hydrogenation product separation system for separation. The hydrogenation product enters the gas-liquid separation tank for gas-liquid separation, and the gas phase is mainly hydrogen, which is compressed by the compressor and recycled. The liquid phase product mainly contains ethanol and cyclohexanol, may also contain a certain amount of ethyl acetate and cyclohexanone, and may also contain a certain amount of unreacted cyclohexyl acetate, and a small amount of reboiler (dipolyketone) , these mixtures are separated by rectification and/or extraction separation. The present invention preferably uses rectification to separate the ester hydrogenation products. Rectification can adopt batch scheme, also can adopt continuous process scheme. Batch rectification, that is, put the ester hydrogenation product into the rectification column, and distill ethanol, ethyl acetate, cyclohexanol, cyclohexanone, and cyclohexyl acetate from the top of the column in turn, leaving a small amount of high boilers remaining in the column. Batch rectification can separate multiple components by using one column, but frequent switching operations result in unstable product quality and low processing capacity, so it is often used in laboratories or small-scale product production. The present invention further preferably adopts continuous rectification to separate the esterification products. Continuous distillation requires the separation of the various components using a series of columns. Various separation processes can be designed according to the sequence of separation of each component. The present invention prefers the process scheme of sequential separation, that is, the hydrogenation product separation system is sequentially equipped with a gas-liquid separation tank for separating hydrogen, and a rectification tank for separating ethanol. tower, a rectification tower for separating cyclohexanol, and a rectification tower for separating cyclohexyl acetate, that is, the addition esterification hydrogenation product first enters the gas-liquid separation tank to separate hydrogen, and then enters the ethanol removal in turn The ethanol is separated in the tower, and then enters the decyclohexanol tower to separate to obtain cyclohexanol, and finally enters the cyclohexyl acetate recovery tower to recover unreacted cyclohexyl acetate, and a small amount of high boiling matter remaining in the tower is sent out to the system. According to the above separation method, after the hydrogenation reaction material enters the hydrogenation product separation system for separation, the separated cyclohexyl acetate can be recycled back to the hydrogenation reactor.

The present invention also provides another method for coproducing cyclohexanol and ethanol, comprising:

(1) Input acetic acid and cyclohexene raw materials into the pre-esterification reactor, and react in the presence of a solid acid catalyst; the cyclohexene raw materials are cyclohexene or cyclohexene and cyclohexane and/or benzene the composition of the mixture;

(2) inputting the discharge of step (1) into a reactive distillation tower, contacting with a solid acid catalyst, reacting, and simultaneously separating the reaction product to obtain cyclohexyl acetate from the bottom of the tower;

(3) The cyclohexyl acetate obtained in step (2) enters the hydrogenation reactor, and undergoes a hydrogenation reaction in the presence of an ester hydrogenation catalyst. The material after the hydrogenation reaction enters the hydrogenation product separation system for separation to obtain cyclohexyl acetate alcohol and ethanol.

The cyclohexene raw material is the same as the first method provided by the present invention.

The cyclohexene raw material is a mixture of cyclohexene, cyclohexane and/or benzene, and a mixture of acetic acid, cyclohexane and/or benzene is obtained from the top of the reactive distillation column.

The pre-esterification reactor can be a tank reactor, a fixed bed reactor, a fluidized bed reactor or an ebullated bed reactor. The fixed-bed reactor is preferably a tubular fixed-bed reactor, more preferably a shell-and-tube reactor. The operation mode of the pre-esterification reaction system can be carried out in a batch mode or in a continuous mode, preferably in a continuous mode. Since the tubular fixed-bed reactor has the advantages of low manufacturing cost and simple operation, it is the preferred reactor of the present invention. Fixed bed reactors can be operated adiabatically or isothermally. The adiabatic reactor can be a cylinder reactor, the catalyst is fixed in the reactor, and the outer wall of the reactor is heat-insulated. Since the addition esterification reaction is an exothermic reaction, it is necessary to control the concentration of the reactants to control the temperature rise of the reactor bed, or use part of the reaction product to cool and then circulate to the reactor inlet to dilute the concentration of the reactants. The isothermal reactor can be a shell-and-tube reactor. The catalyst is fixed in the tube, and cooling water is passed through the shell to remove the heat released by the reaction.

The pre-esterification reaction needs to be carried out at a certain temperature. If the temperature is too low, the reaction rate is low, and if the temperature is too high, although the reaction rate is greatly accelerated, side reactions are also prone to occur, which is unfavorable to the equilibrium conversion rate of the esterification reaction. The selected reaction temperature is related to the catalyst, generally 50-200°C, preferably 60-120°C.

The pressure of the pre-esterification reaction is related to the reaction temperature. Since the addition esterification reaction is carried out in the liquid phase, the reaction pressure should ensure that the reaction is in the liquid phase state. Generally, the reaction pressure is from normal pressure to 10 MPa, preferably from normal pressure to 1 MPa.

The acid-to-ene molar ratio of the pre-esterification reaction is 0.2-20:1, preferably 1.2-4:1.

The liquid feeding space velocity of the pre-esterification reaction is 0.5-20h ^-1 , and the optimal condition is 1-5h ^-1 .

The output of step (1) contains unreacted acetic acid, cyclohexene and esterification product cyclohexyl acetate, if the mixture of cyclohexene and cyclohexane and/or benzene is used as raw material, the output of step (1) The feed also contains cyclohexane and/or benzene.

Under the above conditions, the conversion of cyclohexene in the pre-esterification reaction can generally reach more than 80%, while the selectivity of the esterification reaction can reach more than 99%.

In the first method provided by the present invention, the form of the reactive distillation column and the way of arranging the catalyst have been described in detail, and will not be repeated here.

The reactive distillation column must have enough theoretical plate numbers and reaction plate numbers to meet the reaction and separation requirements. The theoretical plate number of the reactive distillation tower is 10-150, wherein 5-30 plates are selected between 10-120 plates to arrange the solid acid catalyst, and the more preferred scheme is that the theoretical plate number of the reaction tower is 30 ～100, among which 8～20 plates are selected among 10～80 plates to arrange the solid acid catalyst.

In the present invention, it is necessary to ensure that the reactants have sufficient residence time to realize the complete conversion of cyclohexene. Relative to the total loading volume of the catalyst, the space velocity of the liquid feed is 0.1 to 20 h ^-1 , preferably 0.2 to 2 h ^-1 .

In the present invention, the operating pressure of the reactive distillation column can be operated under negative pressure, normal pressure and pressurized conditions. The operating pressure of the reactive distillation tower is -0.0099MPa to 5MPa, preferably normal pressure to 1MPa.

The operating temperature of the reactive distillation tower is related to the pressure of the reactive distillation tower. The temperature distribution of the reaction tower can be adjusted by adjusting the operating pressure of the reaction tower so that the temperature of the catalyst loading area is within the active temperature range of the catalyst. The temperature of the catalyst loading area is generally between 40°C and 200°C, preferably between 60°C and 150°C.

In the present invention, when the cyclohexene raw material is cyclohexene, if pure cyclohexene and acetic acid are used as reaction raw materials, total reflux can be realized theoretically. When there is a small amount of light component impurities in the reaction raw materials, it is necessary to lead a small amount of overhead stream out of the reactive distillation column. Preferably, after impurities are separated from the drawn stream, it is recycled to the reactive distillation column.

In the present invention, the reflux ratio is 0.1-100:1, preferably 0.5-10:1. Preferably, the stream withdrawn from the top of the tower is separated, and the separated stream rich in acetic acid is recycled to the reactive distillation column.

The solid acid catalyst in step (1) and the solid acid catalyst in step (2) can be the same or different, and are selected from one or more of strong acid ion exchange resin catalysts, heteropolyacid catalysts and molecular sieve catalysts.

In the first method provided by the present invention, the strong acid ion exchange resin catalyst, heteropolyacid catalyst and molecular sieve catalyst have been described in detail, and will not be repeated here.

Preferably, the number of theoretical plates of the reactive distillation column is 30 to 100, and 8 to 20 plates are selected between 10 to 80 plates to arrange the solid acid catalyst; the solid acid catalyst is macroporous strong acid Hydrogen type ion exchange resin or cesium phosphotungstate salt; relative to the total loading volume of the catalyst, the liquid feed space velocity is 0.2~2h ^-1 ; the operating pressure of the reactive distillation tower is -0.0099MPa to 5MPa; the catalyst loading The temperature of the zone is between 120-180°C; the reflux ratio is 0.5-10:1.

The above-mentioned method is characterized in that: the esterification reaction of cyclohexene and acetic acid is realized by combining pre-esterification and reactive distillation esterification; The complete conversion of cyclohexene can be achieved further by placing a small amount of catalyst in it.

The invention provides a high-efficiency, low-cost new technology route for producing cyclohexanol. The characteristics of the present invention are: (1) The combination of reaction and rectification separation can be used as the esterification raw material of the product stream of partial hydrogenation of benzene or the cyclohexene-containing stream separated by one-step extraction, and the complete conversion of cyclohexene can be realized , so as to avoid or simplify the extraction and rectification separation process with high investment and operating costs; (2) the process flow is simple, low investment, low energy consumption; (3) both esterification and hydrogenation reactions have high selectivity, so Atom utilization is very high; (4) The process is environmentally friendly; (5) Co-production of ethanol while producing cyclohexanol, that is, converting cheap acetic acid into ethanol with high price and huge market capacity through an indirect way, greatly increasing the process economy.

The present invention is further described by the following examples, but the present invention is not limited thereto.

Detailed ways

Embodiments 1-4 are used to illustrate the method for preparing cyclohexyl acetate by reactive distillation.

The tests carried out in Examples 1 to 4 are all carried out in the reactive distillation model test device of the following specifications: the main body of the model device is a stainless steel tower with a diameter (inner diameter) of 50mm and a height of 3m, and the lower connecting volume of the tower is The 5L tower kettle is equipped with a 10KW electric heating rod in the kettle. The heating rod is controlled by an intelligent controller through a silicon controlled rectifier (SCR). ^A condenser with a heat exchange area of 0.5m2 is connected to the top of the tower, and the steam at the top of the tower is condensed into a liquid by the condenser and then enters a reflux tank with a volume of 2L. The liquid in the reflux tank is partially refluxed to the reaction tower through the reflux pump, and part of it is extracted as light components. The operating parameters of the tower are displayed and controlled by intelligent automatic control instruments. The reflux flow of the tower is controlled by the reflux regulating valve, and the output at the top of the tower is controlled by the liquid level controller of the reflux tank. The production volume of the tower kettle is controlled by adjusting the tower kettle discharge valve by the tower kettle liquid level controller. The raw materials acetic acid and cyclohexene are put into 30L storage tanks respectively, and are pumped into corresponding preheaters through metering pumps to preheat to a certain temperature before entering the reaction tower. The feeding speed is controlled by metering pumps and accurately measured by electronic scales.

Example 1

Grind the high-temperature-resistant sulfonic acid ion-exchange resin (Amberlyst45, produced by Rhom&Hass) with a multi-stage high-speed pulverizer into a powder with a particle size of less than 200 mesh (0.074mm), and add pore-forming agents, lubricants, and antioxidants Mix evenly with the adhesive on a high-speed mixer, and then banbury on an internal mixer at 180°C for 10 minutes to make the material completely plasticized, and then inject it into a mold to make a Raschig ring shape with a diameter of 5mm, a height of 5mm, and a wall thickness of 1mm. Resin catalyst packing. Put 1950mL of this packing into the middle of the model reaction tower (1m in height, equivalent to 8 theoretical trays) and 1950mL of glass spring packing with a diameter of 3mm and a length of 6mm (filling height is 1m, equivalent to 10 theoretical trays). plate). The cyclohexene and acetic acid were pumped into the preheater by the metering pump to preheat and enter the reaction tower, and the heating capacity of the tower reactor and the reflux flow at the top of the tower were adjusted for continuous reaction. The reaction conditions and reaction results under stable operation are shown in Table 1.

Example 2

The configuration of reaction tower and catalyst is identical with embodiment 1. Only cyclohexene, cyclohexane and benzene mixture were used instead of cyclohexene for experimentation, and the reaction tower was operated under the condition of 0.3MPa. Adjust the heating capacity of the tower kettle and the reflux flow at the top of the tower to continuously react. The reaction conditions and reaction results under stable operation are shown in Table 2.

Example 3

Mix the spherical H _0.5 Cs ₂₅ PW ₁₂ O ₄₀ /SiO ₂ catalyst with a diameter of 3-4 (made of H _0.5 Cs ₂₅ PW ₁₂ O ₄₀ powder and coarse-pore silica gel powder with a particle size of less than 200 meshes in a mixer, and then In the sugar coating machine, silica sol is used as a bonding machine to roll the ball into shape, and then dried and roasted) sandwiched into a titanium wire mesh wave plate to make a cylindrical structured packing with a diameter of 50mm and a height of 50mm. Put this packed catalyst L into the middle of the model reaction tower (1m in height, equivalent to 12 theoretical trays), and put 1950mL glass spring packing with a diameter of 4mm and a height of 4mm in the upper and lower parts (the packing height is 1m, equivalent to 15 block theoretical plate). The cyclohexene and benzene were pumped into the preheater by the metering pump to preheat and enter the reaction tower, and the heating capacity of the tower reactor and the reflux flow at the top of the tower were adjusted for continuous reaction. The reaction conditions and reaction results under stable operation are shown in Table 3.

Example 4

The configuration of reaction tower and catalyst is identical with example 3. Just use cyclohexene, cyclohexane and benzene mixture instead of cyclohexene for experiment, and the reaction tower is operated under the condition of 0.2MPa. Adjust the heating capacity of the tower kettle and the reflux flow at the top of the tower to continuously react. The reaction conditions and reaction results under stable operation are shown in Table 4.

Embodiments 5-8 are used to illustrate the method for preparing cyclohexyl acetate by pre-esterification and reactive distillation.

The tests carried out in Examples 5 to 8 were all carried out in a cyclohexyl acetate model test device. The model device consists of a fixed-bed pre-esterification reactor and a reactive distillation esterification tower. The pre-esterification reactor is a 316L stainless steel tube of φ48×4×1200mm. The reaction tube has a hot water jacket outside, and hot water can be passed into the jacket to control the reaction temperature. The reactive distillation esterification tower is a titanium steel (TA2) tower with a diameter (inner diameter) of 50mm and a height of 3m. The lower part of the tower is connected to a tower kettle with a volume of 5L, and a 10KW electric heating rod is installed in the kettle. The heating rod is controlled by an intelligent controller through a silicon controlled rectifier (SCR) to control the heating capacity of the tower kettle. A condenser with a heat exchange area of 0.5 m ² and a reflux tank with a volume of 2 L are connected to the top of the tower. The raw materials acetic acid and cyclohexene are respectively loaded into a 30L storage tank, and pumped into a pre-esterification reactor through a metering pump for reaction, and the pre-esterification product enters a reactive distillation tower for further reaction. The heating capacity of the reaction tower is adjusted by adjusting the heating power of the tower kettle. Adjust the reflux ratio of the column through the top reflux ratio regulator. Light components are withdrawn from the top of the column. The cyclohexyl acetate product is withdrawn from the bottom of the column.

Example 5

500mL of macroporous strongly acidic hydrogen-type ion exchange resin (synthesized in the laboratory according to the classic literature method, suspension copolymerization of styrene solution containing 15% divinylbenzene to make white balls, and then sulfonated with concentrated sulfuric acid, measured Its exchange capacity is 5.2mmolH ⁺ /g dry basis) is loaded into the middle part of the pre-reactor, and a certain amount of quartz sand is filled at both ends. In addition, the high-temperature-resistant sulfonic acid ion exchange resin (the brand is Amberlyst45, produced by Rhom&Hass Company) was crushed into a powder with a particle size of less than 200 mesh (0.074mm) with a multi-stage high-speed pulverizer, and pore-forming agents, lubricants, and antioxidants were added. The agent and adhesive are mixed evenly on a high-speed mixer, and then internally kneaded on an internal mixer at 180°C for 10 minutes to make the material completely plasticized, and then injected into a mold to make a Raschig ring with a diameter of 5mm, a height of 5mm, and a wall thickness of 1mm. type resin catalyst filler. Put 1950mL of this packing into the middle of the model reaction tower (1m in height, equivalent to 8 theoretical trays) and 1950mL of glass spring packing with a diameter of 3mm and a length of 6mm (filling height is 1m, equivalent to 10 theoretical trays). plate). The cyclohexene and acetic acid are pumped into the pre-reactor by the metering pump for reaction, and the pre-reaction product enters the reaction tower for further reaction. The pre-reaction temperature was adjusted by adjusting the temperature of the hot water in the jacket of the pre-reactor. Adjust the heating capacity of the tower kettle and the reflux flow at the top of the tower to continuously react, and the reaction conditions and reaction results of the stable operating conditions are shown in Table 5.

Example 6

The configuration of reaction tower and catalyst is identical with embodiment 5. Only cyclohexene, cyclohexane and benzene mixture were used instead of cyclohexene for testing, and the pressure of the pre-reactor was 2.0MPa, and the reaction tower was operated under normal pressure. Adjust the heating capacity of the tower kettle and the reflux flow at the top of the tower to continuously react, and the reaction conditions and reaction results of the stable operating conditions are shown in Table 6.

Example 7

Put 500mL φ3～4 spherical H _0.5 Cs _2.5 PW ₁₂ O ₄₀ /SiO ₂ catalyst into the middle of the pre-reactor, and fill a certain amount of quartz sand at both ends. In addition, spherical H _0.5 Cs ₂₅ PW ₁₂ O ₄₀ /S iO ₂ catalyst with a diameter of 3-4 (composed of H _0.5 Cs ₂₅ PW ₁₂ O ₄₀ powder and coarse-pore silica gel powder with a particle size of less than 200 meshes, fully mixed in a mixer , in the sugar coating machine, the silica sol is used as the bonding machine to roll the ball, and then dried and roasted) sandwiched into the titanium wire mesh wave plate to make a cylindrical structured packing with a diameter of 50mm and a height of 50mm. Put this packed catalyst L into the middle of the model reaction tower (1m in height, equivalent to 12 theoretical trays), and put 1950mL glass spring packing with a diameter of 4mm and a height of 4mm in the upper and lower parts (the packing height is 1m, equivalent to 15 block theoretical plate). The cyclohexene and acetic acid are pumped into the pre-reactor by the metering pump for reaction, and the pre-reaction product enters the reaction tower for further reaction. The pre-reaction temperature was adjusted by adjusting the temperature of the hot water in the jacket of the pre-reactor. Adjust the heating capacity of the tower kettle and the reflux flow at the top of the tower to continuously react, and the reaction conditions and reaction results of the stable operating conditions are shown in Table 7.

Example 8

The configuration of reaction tower and catalyst is identical with example 7. Only cyclohexene, cyclohexane and benzene mixture were used instead of cyclohexene for testing, and the pre-reaction pressure of 2.0MPa reaction tower was operated under the condition of 0.2MPa. Adjust the heating capacity of the tower kettle and the reflux flow at the top of the tower to continuously react, and the reaction conditions and reaction results of the stable operating conditions are shown in Table 8.

Embodiments 9-10 are used to illustrate the hydrogenation method of cyclohexyl acetate.

Example 9

The raw material for hydrogenation is cyclohexyl acetate with a purity of 99.6%.

40g copper zinc aluminum ester hydrogenation catalyst (laboratory synthesis, composition is CuO40.5%, _ZnO29.6 %, _Al2O330.4 %. By the nitrate solution of copper, zinc, chromium, add in the sodium hydroxide solution and to PH=9.0, centrifuged, washed, dried, pressed into tablets, and roasted) into the middle of a stainless steel tube reactor with a jacket of φ20×2.5×800mm, and a certain amount of quartz sand is filled at both ends . Pass in hydrogen (500mL/min) and reduce for 24h under the conditions of 280°C and 6MPa, then drop to the temperature and pressure of hydrogenation reaction. The cyclohexyl acetate is pumped into the reactor by the metering pump, the hydrogen gas enters the reaction system through the mass flow controller for hydrogenation reaction, the reaction temperature is controlled by introducing heat transfer oil into the outer jacket of the reaction tube, and the reaction temperature is controlled by the back pressure valve at the outlet of the reactor. Control the reactor pressure. The reaction product is sampled through the linear sampling valve at the rear of the reactor for online chromatographic analysis. The reaction conditions and results are shown in Table 9. The results in Table 9 show that, using the copper-zinc-aluminum catalyst, the conversion rate of cyclohexyl acetate hydrogenation reaction can reach more than 99.0%, and the selectivity of cyclohexanol is greater than 99.9%. After 1000 hours of operation, the conversion rate and selectivity have not decreased.

Example 10

The raw material for hydrogenation is cyclohexyl acetate with a purity of 99.6%.

Pack 40g of copper chromium ester hydrogenation catalyst (commercially available, produced by Taiyuan Xinjida Chemical Co., Ltd., brand name is C1-XH-1, CuO content is 55%, diameter 5mm tablet, crushed into 10-20 mesh particles) Enter the middle part of the φ20×2.5×800mm jacketed stainless steel tube reactor, and fill a certain amount of quartz sand at both ends. Pass in hydrogen (500mL/min) and reduce for 24h under the conditions of 280°C and 6MPa, then drop to the reaction temperature and pressure. The cyclohexyl acetate is pumped into the reactor by the metering pump, the hydrogen gas enters the reaction system through the mass flow controller for hydrogenation reaction, the reaction temperature is controlled by introducing heat transfer oil into the outer jacket of the reaction tube, and the reaction temperature is controlled by the back pressure valve at the outlet of the reactor. Control the reactor pressure. The reaction product is sampled through the linear sampling valve at the rear of the reactor for online chromatographic analysis. The reaction conditions and results are shown in Table 10. The results in Table 10 show that with the copper-zinc-aluminum catalyst, the conversion rate of cyclohexyl acetate hydrogenation reaction can reach a maximum of 98.0%, and the selectivity of cyclohexanol is greater than 99.9%. After 500 hours of operation, the conversion rate and selectivity have not decreased.

Example 11

Collect the reaction product 4000g of example 9～10, carry out rectifying separation test. The rectification adopts a glass tower with a height of 2m. The tower column is equipped with Ф3mm stainless steel θ mesh ring high-efficiency rectification packing. The tower kettle is a 5L glass flask, which is heated by an electric heating mantle and the heating capacity of the tower kettle is adjusted by a pressure regulator. The reflux of the tower is controlled by a reflux ratio regulator. The distillation separation results are shown in Table 11.

Table 1

According to the test data, the conversion rate of cyclohexene is 99%, and the selectivity of cyclohexyl acetate is 99.72%.

Table 2

According to the experimental data, the conversion rate of cyclohexene is calculated as 98.8%, and the selectivity of cyclohexyl acetate is 98.0%.

table 3

According to the test data, the conversion rate of cyclohexene is calculated as 98.7%, and the selectivity of cyclohexyl acetate is 99.43%.

Table 4

According to the experimental data, the conversion rate of cyclohexene is calculated to be 99.35%, and the selectivity of cyclohexyl acetate is 99.6%.

table 5

According to the experimental data, the conversion rate of cyclohexene is calculated to be 99.76%, and the selectivity of cyclohexyl acetate is 99.03%.

Table 6

According to the experimental data, the conversion rate of cyclohexene is calculated to be 98.38%, and the selectivity of cyclohexyl acetate is 99.11%.

Table 7

According to the test data, the conversion rate of cyclohexene is calculated as 99.9%, and the selectivity of cyclohexyl acetate is 99.35%.

Table 8

According to the experimental data, the conversion rate of cyclohexene is calculated as 99.02%, and the selectivity of cyclohexyl acetate is 99.19%.

Table 9 copper zinc aluminum catalyst cyclohexyl ester hydrogenation data

Table 10 copper chromium catalyst cyclohexyl ester hydrogenation test data

Table 11 Distillation separation result of cyclohexyl acetate hydrogenation product

Claims (22)

1. A method for coproducing cyclohexanol and ethanol, comprising: (1) acetic acid and cyclohexene raw materials are input in the reactive distillation tower, contact with solid acid catalyst, react, carry out the separation of reaction product simultaneously, obtain cyclohexyl acetate from the bottom of the tower; Obtain acetic acid and A mixture of cyclohexane and/or benzene; the cyclohexene raw material is a mixture of cyclohexene and cyclohexane and/or benzene, and the cyclohexene content is 20m% to 80m%; (2) The cyclohexyl acetate that step (1) obtains enters hydrogenation reactor, carries out hydrogenation reaction under the presence of ester hydrogenation catalyst, and the material after hydrogenation reaction enters hydrogenation product separation system and separates, and obtains cyclohexyl alcohol and ethanol. 2. according to the described method of claim 1, it is characterized in that, cyclohexene content is 20m%～60m%. 3. according to the described method of claim 1, it is characterized in that, described solid acid catalyst is selected from one or more in strong acid type ion exchange resin catalyst, heteropolyacid catalyst and molecular sieve catalyst. 4. according to the described method of claim 3, it is characterized in that, described strong acid type ion exchange resin is macroporous sulfonic acid type polystyrene-divinylbenzene resin or the sulfonic acid type resin after halogen atom modification . 5. according to the method for claim 3, it is characterized in that, described heteropolyacid catalyst is the heteropolyacid of keggin structure and/or the heteropolyacid acid salt of keggin structure, or the heteropolyacid of load keggin structure Catalyst for heteropolyacid acid salt of acid and/or keggin structure. 6. according to the described method of claim 3, it is characterized in that, described molecular sieve is one or more in Hβ, HY and HZSM-5. 7. The method according to claim 1, characterized in that, the number of theoretical plates of the reactive distillation column is 10 to 150, and the solid acid catalyst is arranged between 1/3 to 2/3 of the number of theoretical plates ; Relative to the total loading volume of the catalyst, the liquid feed space velocity is 0.2-20h ^-1 ; the operating pressure of the reactive distillation column is -0.0099MPa to 5MPa; the temperature of the catalyst loading area is between 50-200°C; the reflux ratio 0.1 to 100:1. 8. according to the described method of claim 1, it is characterized in that, described ester hydrogenation reactor is one or more, and reactor type is selected from tank reactor, fixed bed reactor, ebullating bed reactor and fluidized bed reactor. One or more of the chemical bed reactors. 9. The method according to claim 1, characterized in that, the ester hydrogenation catalyst is selected from one or more of copper-based catalysts and noble metal-based catalysts. 10. The method according to claim 9, wherein the copper-based catalyst is a zinc-containing copper-based catalyst and/or a chromium-containing copper-based catalyst. 11. The method according to claim 1, characterized in that the ester hydrogenation reaction temperature is 150-400°C, the reaction pressure is normal pressure-20MPa, the hydrogen ester molar ratio is 1-1000:1, and the liquid feed space velocity 0.1 to 20h ^-1 . 12. A method for the coproduction of cyclohexanol and ethanol, comprising: (1) acetic acid and cyclohexene raw material are input into pre-esterification reactor, react under the existence of solid acid catalyst; Described cyclohexene raw material is the mixture that cyclohexene and cyclohexane and/or benzene form, cyclohexene The hexene content is 20m%-80m%; the pre-esterification reactor is a tank reactor, a fixed bed reactor, a fluidized bed reactor or an ebullated bed reactor; (2) the output of step (1) is input in the reactive distillation tower, contacts with solid acid catalyst, reacts, and carries out the separation of reaction product simultaneously, obtains cyclohexyl acetate from the bottom of the tower; Obtain acetic acid from the top of the reactive distillation tower Mixtures with cyclohexane and/or benzene; (3) The cyclohexyl acetate that step (2) obtains enters hydrogenation reactor, carries out hydrogenation reaction under the presence of ester hydrogenation catalyst, and the material after hydrogenation reaction enters hydrogenation product separation system and separates, and obtains cyclohexyl alcohol and ethanol. 13. The method according to claim 12, characterized in that the cyclohexene content is 20m%-60m%. 14. The method according to claim 12, characterized in that, the theoretical plate number of the reactive distillation column is 10 to 150, and 5 to 30 plates are selected between 10 to 120 plates in the theoretical plate number The solid acid catalyst is arranged; relative to the total loading volume of the catalyst, the liquid feed space velocity is 0.1-20h ^-1 ; the operating pressure of the reactive distillation column is -0.0099MPa to 5MPa; the temperature of the catalyst bed loading area is 40-200 ℃; the reflux ratio is 0.1～100:1. 15. according to the described method of claim 12, it is characterized in that, the solid acid catalyst of step (1) and the solid acid catalyst of step (2) are respectively selected from strong acid type ion exchange resin catalyst, heteropolyacid catalyst and molecular sieve catalyst one or more of. 16. according to the described method of claim 15, it is characterized in that, described strong acid type ion exchange resin catalyst is macroporous sulfonic acid type polystyrene-divinylbenzene resin or the sulfonic acid type after halogen atom modification resin. 17. according to the described method of claim 15, it is characterized in that, described heteropolyacid catalyst is the heteropolyacid of keggin structure and/or the heteropolyacid acid salt of keggin structure, or is the heteropoly acid salt of load keggin structure Catalyst for heteropolyacid acid salt of acid and/or keggin structure. 18. The method according to claim 15, characterized in that the molecular sieve catalyst is one or more of Hβ, HY and HZSM-5. 19. according to the described method of claim 12, it is characterized in that, described ester hydrogenation reactor is one or more, and reactor type is selected from tank reactor, fixed bed reactor, ebullating bed reactor and fluidized bed reactor. One or more of the chemical bed reactors. 20. The method according to claim 12, characterized in that, the ester hydrogenation catalyst is selected from one or more of copper-based catalysts and noble metal-based catalysts. 21. The method according to claim 20, characterized in that the copper-based catalyst is a zinc-containing copper-based catalyst and/or a chromium-containing copper-based catalyst. 22. The method according to claim 12, characterized in that the ester hydrogenation reaction temperature is 150-400°C, the reaction pressure is normal pressure-20MPa, the hydrogen ester molar ratio is 1-1000:1, and the liquid feed space velocity is 0.1 to 20h ^-1 .