CN109809973B - Method for preparing 2-ethylhexanal - Google Patents
Method for preparing 2-ethylhexanal Download PDFInfo
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- CN109809973B CN109809973B CN201811553761.4A CN201811553761A CN109809973B CN 109809973 B CN109809973 B CN 109809973B CN 201811553761 A CN201811553761 A CN 201811553761A CN 109809973 B CN109809973 B CN 109809973B
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Abstract
The invention relates to a method for preparing 2-ethylhexanal. The method comprises the steps of taking reaction liquid containing 2-ethyl-2-hexenal obtained by condensing and dehydrating n-butyraldehyde as a raw material, firstly contacting with a first-stage catalyst containing Pd, Pt, Cu and Ni to convert aldehyde polymers into 2-ethylhexanal and the like, and then contacting with a second-stage catalyst containing Pd, Co and Ag to convert a small amount of residual 2-ethyl-2-hexenal into 2-ethylhexanal and further decompose the aldehyde polymers; and the rectified kettle bottom liquid containing 2-ethylhexanal, 2-ethyl-2-hexenal, 2-ethylhexanol and the aldehyde polymer is recycled to the first-stage reactor, so that the conversion rate of the 2-ethyl-2-hexenal is improved, and meanwhile, high-boiling-point substances such as the aldehyde polymer and the like are partially converted into the 2-ethylhexanal, so that the yield of the 2-ethylhexanal is improved. The method can continuously produce the 2-ethylhexanal with high selectivity and high yield, and has good product quality and low energy consumption of three wastes.
Description
Technical Field
The invention relates to a preparation method of 2-ethylhexanal, in particular to a method for preparing 2-ethylhexanal by two-stage hydrogenation and two-stage circulation.
Background
2-ethylhexanal, also known as isooctanal (2-EH), is a synthetic raw material for perfumes and isooctanoic acid (also known as 2-ethylhexanoic acid). Isooctanoic acid is an important organic chemical product, can be widely used in the fields of coating, plastics, leather, medicine, wood, chemical fiber, pesticide and the like, but is mostly used for producing metal salt of isooctanoic acid. The isooctoate has a more obvious drying effect than naphthenate, so that the isooctoate is widely used in the coating industry to meet the requirements of people on high-grade light-colored coatings. Isooctanoic acid is mainly used as a salifying reagent for synthesizing penicillin sodium salt by a solvent method in the aspect of medicine. In addition, the glyceryl isooctanoate is an excellent plasticizer, and with the development of industry and agriculture, the demand of the isooctanoic acid is increased year by year, so that the glyceryl isooctanoate has great development potential.
The 2-ethylhexanal is produced by using n-butyl aldehyde as main material and through condensation, dewatering and liquid separation to obtain 2-ethyl-2-hexenal (also called isooctenal) condensation liquid and liquid phase selective hydrogenation of 2-ethyl-2-hexenal to obtain 2-ethylhexanal. The process has the difficulties of realizing high conversion rate of raw materials, simultaneously requiring hydrogenation to selectively occur on carbon-carbon double bonds instead of carbonyl groups, and simultaneously, materials contain double bonds and aldehyde functional groups, which are easy to generate side reactions such as polymerization and the like, thereby causing high three wastes and reducing yield. Therefore, the process and the corresponding catalyst are critical.
The patents DEA1941634 and US3903171A use Pd/SiO2The catalyst uses 2-ethyl-2-hexenal as raw material, and uses the hydrogenation product as solvent circularly, and said process has the defects of high pressure (1-25MPa), small raw material feeding space velocity, low conversion rate and selectivity and low yield of target product.
In patent US4018831A, Pd-Ni/Al is used2O3The catalyst, namely 2-ethyl-2-hexenal is subjected to catalytic hydrogenation at 90-180 ℃ under the pressure of 0.7-3.5 MPa to prepare 2-ethylhexanal, wherein the space velocity is 0.5-3, and the hydrogen-oil ratio is 2: 1-3: 1(mol/mol), the liquid phase upper flow passes through the catalyst bed layer by controlling the hydrogen flow and the reaction condition, the selectivity of the target product is improved, the generation of the byproduct 2-ethylhexanol is reduced, in the embodiment, the conversion rate of the 2-ethyl-2-hexenal is 74 percent, the selectivity of the 2-ethylhexanol is 97.5 percent, and the yield of the target product is low on the whole.
Jihua research institute Lizheng, etc. (literature 2-ethylhexenal liquid phase hydrogenation to 2-ethylhexanal, Jihua science and technology,1991, 1(4): 35-38) to develop selective hydrogenation of 2-ethyl-2-hexenal using Pd/gamma-Al2O3The catalyst contains 0.37% of palladium, a crude 2-ethylhexanal circulation method is adopted, 5L of catalyst is used for testing, the temperature of a reaction hot spot is 85-95 ℃, the pressure is 2.45MPa, the mixture ratio is 3.4: 1-3.8: 1, the hydrogen-oil ratio is 2.6: 1-5.2: 1, and the liquid airspeed of 2-ethyl-2-hexenal is 0.15-0.30 h-1The yield of the 2-ethylhexanal is 97-98%, the production capacity of the 2-ethylhexanal is 0.2g of the 2-ethylhexanal/g.cath, the overall yield is high, but the catalyst treatment capacity is low, and the catalyst cost is high.
Patent US4273945A researches the liquid phase hydrogenation of olefin unsaturated aldehyde to prepare saturated aliphatic aldehyde under the catalysis of palladium catalyst, wherein the active components of the catalyst comprise 2-90% of palladium and 10-98% of rare earth metal oxide or salt, Al2O3The content is more than 90 percent. Wherein, when the reaction pressure is 1-3.5 Mpa and the temperature is 80-150 ℃, the conversion rate of the 2-ethylhexenal is more than 95 percent, and the selectivity of the 2-ethylhexanal is more than 94 percent. The reaction conversion rate and selectivity reported in the patent are not high, and the subsequent separation and the product cost are increased.
The patent CN1569789A adopts a two-section bubbling type heat insulation fixed bed reactor fed from the lower part for hydrogenation, thereby reducing the circulation amount, avoiding channeling, reducing the carbon deposition amount and being beneficial to improving the selectivity; the content of the hydrogenation catalyst palladium is 0.2-0.4% (wt), and the carrier is gamma-Al2O3. Two-section bubbling type heat-insulating fixed bed reactor fed from lower portion is adopted, and the first reactor condition is as follows: the inlet temperature is 50-80 ℃, the hot spot temperature is 80-110 ℃, the reaction pressure is 1.50-2.50 Mpa, and the space velocity is 0.4-1.2 h-1The circulation ratio is 7-20, and the hydrogen ratio is 3-20. The second reactor conditions were: the inlet temperature is 50-70 ℃, the hot spot temperature is 60-80 ℃, and the reaction pressure is 1.50-2.50 Mpa. After two-stage hydrogenation, the conversion rate of the raw material reaches 99.9 percent, and the selectivity of the 2-ethylhexanal reaches more than 99.5 percent. The method is carried out by adopting a mode of feeding materials from the lower part of the material, the relative retention time of the bubbling reactor is longer, and the bubbling is easy to coalesce, so that the reaction result is unstable, and the control conditions of equipment and the process are harsh.
Patent US5756856A in Pd (0.5 wt.%)/γ -Al2O3As a catalyst, carrying out a circulating hydrogenation reaction in a loop formed by two reactors connected in series, wherein the reaction temperature is 80-130 ℃. The pressure is 0.5-2 MPa. Compared with the traditional hydrogenation process, the two-stage hydrogenation process improves the yield by more than 30 percent. The conversion rate of the 2-ethyl hexenal is more than 99.9 percent, and the selectivity of the 2-ethyl hexanal is more than 99 percent. However, the process needs a large recycle ratio for improving the conversion rate and has relatively high energy consumption, and the conditions of heavy components such as aldehyde polymerization and the like are not mentioned.
The n-butyraldehyde is condensed and dehydrated to obtain 2-ethyl-2-hexenal, and meanwhile, a trimer such as butyraldehyde is generated
And 2-ethyl-2-hexenal dimer (2-ethyl-2-hexenal dimer)
And the like.
2-Ethyl-2-hexenal inevitably produces 2-ethylhexanal dimer (2-ethylhexanal dimer) during the hydrogenation
2-Ethylhexanal and 2-ethyl-2-hexenal Polymer (2-Ethylhexanal and 2-ethyl-2-hexenal Polymer)
And the like.
The occurrence of the impurities indirectly reduces the yield of the 2-ethylhexanal, increases the separation difficulty, and influences the large amount of the heavy component waste liquid, so that aiming at the problem, the hydrogenation method needs to be improved, a proper process scheme and a proper catalyst are selected, the generation of high-boiling-point substances such as polymers and the like is effectively inhibited or the high-boiling-point substances such as polymers and the like are decomposed, the yield of the 2-ethylhexanal is improved, and the amount of the heavy component waste liquid is reduced.
Disclosure of Invention
The invention aims to provide a method for preparing 2-ethylhexanal, which aims to solve the problems of high three wastes of heavy components, low whole-process yield, low catalyst processing capacity, high energy consumption in the reaction and subsequent separation processes and the like in the conventional 2-ethylhexanal production process. Through two-stage hydrogenation and two-stage circulation, the high conversion rate of the 2-ethyl-2-hexenal is ensured, and the catalyst treatment capacity is improved; meanwhile, through the circulation of heavy components, the aldehyde polymer impurities are converted into 2-ethylhexanal, the 2-ethylhexanal is reduced and is converted into 2-ethylhexanol through deep hydrogenation, the product yield is further improved, and the three wastes are reduced.
In order to achieve the purpose, the invention adopts the following technical scheme:
a process for preparing 2-ethylhexanal, comprising the steps of:
1) in a first-stage reactor, carrying out a first-stage hydrogenation reaction on a 2-ethyl-2-hexenal raw material and hydrogen under the catalysis of a first-stage catalyst to obtain a first-stage hydrogenation solution;
2) part of the first-stage hydrogenated liquid obtained in the step 1) enters a second-stage reactor, and is subjected to second-stage hydrogenation reaction with hydrogen under the catalysis of a second-stage catalyst to obtain second-stage hydrogenated liquid (hydrogenated liquid containing 2-ethylhexanal); circulating the rest part of the first-stage hydrogenation liquid obtained in the step 1) to a first-stage reactor for circulating hydrogenation;
3) rectifying and separating the second-stage hydrogenated liquid in the step 2) to obtain a 2-ethylhexanal product, heavy components and light components, wherein one part of the heavy components is recycled to the first-stage reactor for cyclic hydrogenation, and the rest of the heavy components is discharged as waste liquid.
The one-stage catalyst of the invention is a supported catalyst containing Pd, Pt, Cu and Ni, wherein the content of Pd is 0.05-0.5%, preferably 0.08-0.3%, such as 0.08%, 0.12%, 0.16%, 0.20% or 0.25% by mass of the total mass of the catalyst; pt content of 0.01-0.1%, preferably 0.02-0.1%, such as 0.02%, 0.04%, 0.06%, 0.08% or 0.1%; cu content of 0.01-0.1%, preferably 0.02-0.1%, such as 0.02%, 0.04%, 0.06%, 0.08% or 0.1%; ni content of 0.01-0.1%, preferably 0.02-0.1%, such as 0.02%, 0.04%, 0.06%, 0.08% or 0.1%; the carrier is 99.2-99.92%, preferably 99.45-99.86%.
The two-stage catalyst of the present invention is a supported catalyst comprising Pd, Co and Ag, with the Pd content being 0.5-1%, preferably 0.6-0.8%, such as 0.5%, 0.6%, 0.7%, 0.8% or 1%, based on the total mass of the catalyst; the Co content is 0.02-0.2%, preferably 0.06-0.16%, such as 0.02%, 0.06%, 0.1%, 0.16% or 0.2%; ag in an amount of 0.02-0.2%, preferably 0.06-0.16%, such as 0.02%, 0.06%, 0.1%, 0.16% or 0.2%; 98.6 to 99.46%, preferably 98.88 to 99.28% of the carrier.
In the step 1), the first-stage catalyst has a remarkable decomposition effect on aldehyde polymers (namely aldol condensation products) besides good double-bond selective hydrogenation.
The catalyst has high adsorption effect on oxygen while adsorbing and hydrogenating carbon-carbon double bonds, the active center of the catalyst is combined with the oxygen in carbonyl and hydroxyl in the structure to form a six-ring intermediate state, and then C-C bond fracture and resolution are carried out to form two molecules of aldehyde. Specifically, butyraldehyde trimer is decomposed into 2-ethylhexanal and 2-ethyl-3-hydroxyhexanal, and the 2-ethyl-3-hydroxyhexanal is easy to generate dehydration reaction to generate 2-ethyl-2-hexenal; 2-ethylhexanal dimer is decomposed into two molecules of 2-ethylhexanal; 2-ethyl-2-hexenal dimer is decomposed into two molecules of 2-ethyl-2-hexenal; the 2-ethylhexanal and 2-ethyl-2-hexenal polymer are decomposed into a molecule of 2-ethylhexanal and a molecule of 2-ethyl-2-hexenal.
In the step 2), compared with the first-stage hydrogenation raw material, the concentration of 2-ethyl-2-hexenal in the second-stage hydrogenation raw material is obviously reduced, the concentration of 2-ethylhexanal is obviously increased, and the reaction speed of the deep hydrogenation and polymerization of 2-ethylhexanal in the second-stage hydrogenation process is higher than that of the first-stage hydrogenation raw material, so that the formula and the reaction temperature of the catalyst need to be adjusted, the conversion rate of 2-ethyl-2-hexenal is ensured, the side reaction is reduced, and the overall yield is improved. The reaction temperature is reduced, the main and side reaction speeds can be effectively reduced, and the selectivity is improved; the content of active metal Pd in the catalyst is improved, the conversion rate of raw materials is ensured during low-temperature operation, the formula of the catalyst is adjusted, and Co and Ag metal elements are added, so that the selectivity of carbon-carbon double bonds is improved.
The 2-ethyl-2-hexenal raw material can be reaction liquid containing 2-ethyl-2-hexenal obtained by condensing and dehydrating n-butyl aldehyde. The process for preparing 2-ethyl-2-hexenal from n-butyraldehyde is well known in the art, and in the present invention, the composition of the reaction solution containing 2-ethyl-2-hexenal comprises: 0.5-1.5 wt% of n-butyraldehyde, 95-97 wt% of 2-ethyl-2-hexenal, and 2.5-3.5 wt% of aldehyde polymer (comprising butyraldehyde trimer 1-2.5 wt%, 2-ethyl-2-hexenal dimer 1-1.5 wt%).
In step 1) of the invention, the temperature of the first-stage hydrogenation reaction is 80-120 ℃, such as 90 ℃, 100 ℃ or 110 ℃; the pressure (absolute pressure) is 1-5MPa, such as 1.5, 3.0 or 4.5 MPa.
In step (1) of the present invention, the molar ratio of hydrogen to 2-ethyl-2-hexenal is 5-25:1, such as 10:1 or 20: 1.
In the step 2) of the invention, the temperature of the second-stage hydrogenation reaction is 50-90 ℃, such as 60 ℃, 70 ℃ or 80 ℃; the pressure (absolute pressure) is 1-5MPa, such as 1.5, 3.0 or 4.5 MPa.
The hydrogen of the second-stage hydrogenation reaction is the hydrogen at the outlet of the first-stage hydrogenation reactor.
The mass ratio of the first-stage catalyst to the second-stage catalyst is 1-10:1, such as 3:1, 6:1 or 9: 1.
In the method, the total liquid hourly space velocity is 0.1-1h-1E.g. 0.2, 0.5, 0.8h-1. The meaning of the total liquid hourly space velocity is the mass of 2-ethyl-2-hexenal in a unit mass of catalyst (based on the sum of the mass of the first-stage catalyst and the mass of the second-stage catalyst) in the 2-ethyl-2-hexenal raw material treated per hour.
In the step 3) of the invention, the rectification separation conditions are that the separation pressure (absolute pressure) is 10-30kPa, the temperature of the tower bottom is 100-150 ℃, the temperature of the tower top is 90-122 ℃, and the number of separation trays is 10-30, such as 20.
In the step 2) of the present invention, the circulation ratio of the first-stage hydrogenation solution (the ratio of the rest of the first-stage hydrogenation solution to a part of the first-stage hydrogenation solution) is 10-40:1, such as 20:1 or 30: 1.
The recycle ratio of the heavies in step 3) of the process of the invention (ratio of a portion of the heavies to the remainder of the heavies) is 60-100:1, such as 70:1, 80:1 or 90: 1.
The preparation method of the first-stage catalyst comprises the following steps: according to the proportion,
a1) simultaneously dripping a mixed aqueous solution of compounds containing Pd, Pt, Cu and Ni and an alkaline precipitator into a nano oxide aqueous dispersion for reaction, controlling the temperature of a reaction system to be 80-90 ℃ and the pH value to be 5.0-8.0 in the reaction process, dripping for 2-3h, adjusting the pH value of the system to be 7.5-9.0 by using the alkaline precipitator after finishing dripping, heating to 85-95 ℃, then aging, and cooling to normal temperature after 1-2h to obtain slurry;
b1) filtering and washing the slurry, drying at 120 ℃ of 100-24 h, roasting at 1200 ℃ of 800-10 h, crushing, tabletting and forming, reducing the catalyst by adopting hydrogen at 150 ℃ of 120-5 MPa for 24-48h, and drying to remove reducing water to obtain the first-stage catalyst.
In step a1) of the present invention, the solid content of the mixed aqueous solution of compounds containing Pd, Pt, Cu and Ni is 0.2-2 wt%, such as 0.5 wt%, 1.0 wt% or 1.5 wt%.
The preparation method of the two-stage catalyst comprises the following steps: according to the proportion,
a2) simultaneously dripping a mixed aqueous solution of compounds containing Pd, Co and Ag and an alkaline precipitator into a nano oxide aqueous dispersion for reaction, controlling the temperature of a reaction system to be 80-90 ℃ and the pH of the reaction system to be 5.0-8.0 in the reaction process, dripping for 2-3h, adjusting the pH of the system to be 7.5-9.0 by using the alkaline precipitator after finishing dripping, heating to 85-95 ℃ for aging, and cooling to normal temperature after 1-2h to obtain slurry;
b2) filtering and washing the slurry, drying at 120 ℃ of 100-.
In step a2) according to the invention, the mixed aqueous solution of compounds comprising Pd, Co and Ag has a solids content of 0.2-2 wt.%, such as 0.5 wt.%, 1.0 wt.% or 1.5 wt.%.
The particle size of the nano oxide is 20-50 nm; the nano-oxide is used in an amount of 0.5 to 2 wt%, such as 1 wt% or 1.5 wt%, based on the solid content of the dispersion. The nano oxide is selected from one or more of nano aluminum oxide, nano titanium oxide and nano zirconium oxide.
The compound of Pd, Pt, Cu, Ni, Co and Ag is selected from one or more of nitrate, chloride and acetate of the metal, and preferably palladium nitrate, platinum nitrate, copper nitrate, nickel nitrate, cobalt nitrate and silver nitrate.
The alkaline precipitator is one or more of sodium carbonate, potassium carbonate, sodium bicarbonate, potassium bicarbonate, sodium hydroxide, potassium hydroxide, ammonium carbonate, ammonium bicarbonate and ammonia water.
In the invention, the first-stage hydrogenation catalyst decomposes the aldehyde polymer while selectively hydrogenating the 2-ethyl-2-hexenal; the second-stage hydrogenation catalyst ensures that the residual 2-ethyl-2-hexenal in the hydrogenation liquid at the first-stage hydrogenation outlet is hydrogenated, ensures the conversion rate of the 2-ethyl-2-hexenal, and simultaneously continuously decomposes the aldehyde polymer to improve the yield of the 2-ethylhexanal.
Compared with the prior art, the invention has the following advantages:
(1) the first catalyst contains Pd, Pt, Cu and Ni elements, can generate a synergistic effect, can decompose the aldehyde polymer while carrying out double bond hydrogenation with high selectivity, inhibit the polymerization of the aldehyde compound, effectively reduce the production of the polymer and improve the yield of the 2-ethylhexanal.
(2) The two-stage catalyst contains Pd, Co and Ag, effectively ensures complete conversion of 2-ethyl-2-hexenal at low temperature, reduces the selectivity of deep hydrogenation and polymerization of 2-ethylhexanal, and improves the selectivity of 2-ethylhexanal.
(3) 2-ethyl-2-hexenal is subjected to two-stage hydrogenation to produce 2-ethylhexanal, and the concentration of the fed 2-ethyl-2-hexenal is reduced through partial circulation of a hydrogenation liquid at the outlet of a first-stage reactor, so that the control of the bed temperature is facilitated, and dangerous or abnormal working conditions such as temperature runaway and the like caused by large heat release are avoided; the polymer in the distillation tower is decomposed or hydrogenolyzed through partial circulation of the 2-ethylhexanal distillation tower bottoms, so that the yield of the 2-ethylhexanal is improved. The method for producing the 2-ethylhexanal has simple production process, realizes high yield of the product and has considerable economic benefit.
Detailed Description
The process of the present invention will be further illustrated by the following examples, but the present invention is not limited to the examples listed, but also includes any other known variations within the scope of the claims of the present invention.
Wherein, the composition analysis conditions of the gas chromatography in the following examples are as follows: an Agilent HP-5 chromatographic column and an area normalization method, wherein the injection port temperature is 140 ℃, the detector temperature is 250 ℃, the hydrogen flow is 40ml/min, and the air flow is 400 ml/min.
Unless otherwise specified, the reagents used below are all analytical grade, and the contents referred to below are all in mass percent.
Example 1
First-stage catalyst preparation:
adding 65.6L of deionized water into a reaction kettle, then adding 998.6g of nano-alumina with the particle size of 20-50nm to prepare nano-oxide dispersion, wherein the temperature of the dispersion is 75 ℃;
1.73g Pd (NO) was weighed out separately3)2、0.33gPt(NO3)2、0.59gCu(NO3)2、0.62gNi(NO3)2Adding 323.95g of water, simultaneously adding the obtained mixed salt aqueous solution and an alkaline precipitator sodium carbonate into the nano oxide dispersion liquid for reaction at the reaction temperature of 80 ℃, dropwise adding for 2 hours, controlling the pH of the reaction system to be 6 in the reaction process, adding the alkaline precipitator after dropwise adding to adjust the pH to 8, and then aging at the aging temperature of 90 ℃ for 1.5 hours to obtain slurry;
filtering, washing and drying the slurry for 18h at 100 ℃ to obtain a filter cake; then roasting for 8h at 1000 ℃, crushing, tabletting and forming, reducing for 30h at 135 ℃ under 2.5MPa, drying and removing reducing water to obtain 1000g of a section of catalyst.
Preparation of a two-stage catalyst:
adding 13.1L of deionized water into a reaction kettle, then adding 198.92g of nano-alumina with the particle size of 20-50nm to prepare nano-oxide dispersion liquid, wherein the temperature of the dispersion liquid is 75 ℃;
1.67g of PdCl are weighed out2、0.16g CoCl2·6H2O and 0.06g AgNO3Adding 119.35g of water, simultaneously dripping the obtained mixed salt water solution and an alkaline precipitator sodium carbonate into the nano oxide dispersion liquid for reaction at the reaction temperature of 80 ℃ for 2h, controlling the pH of the reaction system to be 6.0 in the reaction process, adding the alkaline precipitator after the dripping is finished to adjust the pH to 8.0, then aging at the aging temperature of 90 ℃ for 1.5h to obtain slurry;
filtering and washing the slurry, drying at 100 ℃ for 18h, then roasting at 1000 ℃ for 8h, crushing, tabletting and forming, reducing by using hydrogen at 135 ℃, under the absolute pressure of 2.5MPa for 30h, and drying to remove reducing water to obtain 200g of the second-stage catalyst.
The first two-stage catalyst is a No. 1 catalyst combination.
Example 2
First-stage catalyst preparation:
adding 98.8L of deionized water into a reaction kettle, and then adding 997.6g of nano titanium oxide with the particle size of 20-50nm to prepare nano oxide dispersion liquid, wherein the temperature of the dispersion liquid is 75 ℃;
2.60g Pd (NO) are weighed out separately3)2、0.65gPt(NO3)2、1.18gCu(NO3)2、1.25gNi(NO3)2Adding 372.8g of water, simultaneously adding the obtained mixed salt aqueous solution and an alkaline precipitator potassium bicarbonate into the nano oxide dispersion liquid for reaction at the reaction temperature of 85 ℃ for 2.5 hours, controlling the pH of a reaction system to be 5 in the reaction process, adding the alkaline precipitator after the dropwise addition is finished to adjust the pH to be 7.5, and then aging at the aging temperature of 85 ℃ for 1 hour to obtain slurry;
filtering, washing and drying the slurry at 100 ℃ for 12h to obtain a filter cake; then roasting for 10h at 800 ℃, crushing, tabletting and forming, reducing for 24h at 120 ℃ under 5MPa, drying and removing reducing water to obtain 1000g of a section of catalyst.
Preparation of a two-stage catalyst:
adding 98.3L of deionized water into a reaction kettle, and then adding 992.8g of nano titanium oxide with the particle size of 20-50nm to prepare nano oxide dispersion liquid, wherein the solid content is 1%, and the temperature of the dispersion liquid is 75 ℃;
weighing 10g of PdCl2、2.42g CoCl2·6H2O and 0.94g AgNO3Adding 1214.22g of water, simultaneously dripping the obtained mixed salt water solution and an alkaline precipitator potassium bicarbonate into the nano oxide dispersion liquid for reaction at the reaction temperature of 85 ℃ for 2.5h, controlling the pH of the reaction system to be 5 in the reaction process, adding the alkaline precipitator after the dripping is finished to adjust the pH to 7.5, and then aging at the aging temperature of 85 for 1h to obtain the slurry.
Filtering and washing the slurry, drying at 100 ℃ for 12h, roasting at 800 ℃ for 10h, crushing, tabletting and forming, reducing by using hydrogen at 120 ℃, under the absolute pressure of 5MPa for 24h, and drying to remove reducing water to obtain 1000g of the second-stage catalyst.
The first two-stage catalyst is a No. 2 catalyst combination.
Example 3
First-stage catalyst preparation:
adding 198.3L of deionized water into the reaction kettle, then adding 996.6g of nano zirconia with the particle size of 20-50nm to prepare nano oxide dispersion liquid, wherein the temperature of the dispersion liquid is 75 ℃;
3.46g Pd (NO) were weighed out separately3)2、0.98gPt(NO3)2、1.77gCu(NO3)2、1.87gNi(NO3)2Adding 1608.80g of water, simultaneously adding the obtained mixed salt aqueous solution and an alkaline precipitator ammonium bicarbonate into the nano oxide dispersion liquid for reaction at the reaction temperature of 85 ℃ for 2.5h, controlling the pH of the reaction system to be 7 in the reaction process, adding the alkaline precipitator after the dropwise addition is finished to adjust the pH to 8.5, then aging at the aging temperature of 90 ℃ for 2h to obtain slurry;
filtering, washing and drying the slurry at 100 ℃ for 24 hours to obtain a filter cake; then roasting for 5h at 1200 ℃, crushing, tabletting and forming, reducing for 48h at 150 ℃ under 1MPa, and drying to remove reducing water to obtain 1000g of a first-stage catalyst.
Preparation of a two-stage catalyst:
adding 19.7L of deionized water into a reaction kettle, then adding 99.1g of nano zirconia with the particle size of 20-50nm to prepare nano oxide dispersion, wherein the temperature of the dispersion is 75 ℃;
1.17g of PdCl are weighed out2、0.4g CoCl2·6H2O and 0.16g AgNO3Adding 307.3g of water, simultaneously dripping the obtained mixed salt water solution and an alkaline precipitator ammonium bicarbonate into the nano oxide dispersion liquid for reaction at the reaction temperature of 85 ℃ for 2.5h, controlling the pH of the reaction system to be 7 in the reaction process, adding the alkaline precipitator after the dripping is finished to adjust the pH to 8.5, then aging at the aging temperature of 90 ℃ for 2h to obtain slurry;
and filtering and washing the slurry, drying the slurry at 100 ℃ for 24h, roasting the slurry at 1200 ℃ for 5h, crushing the slurry, tabletting the slurry to form a sheet, reducing the sheet by using hydrogen at 150 ℃, keeping the absolute pressure of the sheet at 1MPa for 48h, and drying the sheet to remove reducing water to obtain 100g of the second-stage catalyst.
The first two-stage catalyst is a No. 3 catalyst combination.
Example 4
First-stage catalyst preparation:
adding 65.4L of deionized water into a reaction kettle, then adding 995.6g of nano-alumina with the particle size of 20-50nm to prepare nano-oxide dispersion liquid, wherein the temperature of the dispersion liquid is 80 ℃;
separately weigh 4.33g Pd (NO)3)2、1.31gPt(NO3)2、2.36gCu(NO3)2、2.49gNi(NO3)2Adding 5234.80g of water, simultaneously adding the obtained mixed salt aqueous solution and an alkaline precipitator potassium hydroxide into the nano oxide dispersion liquid for reaction at the reaction temperature of 90 ℃, dropwise adding for 3 hours, controlling the pH of the reaction system to be 7.5 in the reaction process, adding the alkaline precipitator after dropwise adding to adjust the pH to 8.5, then aging at the aging temperature of 95 ℃, and aging for 2 hours to obtain slurry;
filtering, washing and drying the slurry at 100 ℃ for 16h to obtain a filter cake; then roasting for 8h at 900 ℃, crushing, tabletting and forming, reducing for 35h at 130 ℃ under 4MPa, drying and removing reducing water to obtain 1000g of a section of catalyst.
Preparation of a two-stage catalyst:
adding 21.6L of deionized water into a reaction kettle, then adding 329.6g of nano-alumina with the particle size of 20-50nm to prepare nano-oxide dispersion liquid, wherein the temperature of the dispersion liquid is 80 ℃;
weighing 4.44g of PdCl2、2.15g CoCl2·6H2O and 0.84g AgNO3Adding 424.11g of water, simultaneously dripping the obtained mixed salt aqueous solution and an alkaline precipitator potassium hydroxide into the nano oxide dispersion liquid for reaction at the reaction temperature of 90 ℃ for 3h, controlling the pH of the reaction system to be 7.5 in the reaction process, adding the alkaline precipitator after the dripping is finished to adjust the pH to 8.5, then aging at the aging temperature of 95 ℃ for 2h to obtain slurry;
filtering and washing the slurry, drying for 16h at 100 ℃, roasting for 8h at 900 ℃, crushing, tabletting and forming, reducing by using hydrogen at 130 ℃, under the absolute pressure of 4MPa for 35h, and drying to remove reducing water to obtain 333.3g of a two-stage catalyst.
The first two-stage catalyst is a No. 4 catalyst combination.
Example 5
First-stage catalyst preparation:
adding 48.7L of deionized water into a reaction kettle, then adding 994.5g of nano-alumina with the particle size of 20-50nm to prepare nano-oxide dispersion, wherein the temperature of the dispersion is 70 ℃;
separately, 5.41g of Pd (NO) was weighed3)2、1.64gPt(NO3)2、2.95gCu(NO3)2、3.11gNi(NO3)2Adding 642.55g of water, simultaneously adding the obtained mixed salt aqueous solution and alkaline precipitator ammonia water into the nano oxide dispersion liquid for reaction at the reaction temperature of 90 ℃, dropwise adding for 3 hours, controlling the pH of the reaction system to be 8 in the reaction process, adding the alkaline precipitator after dropwise adding to adjust the pH to 9, then aging at the aging temperature of 95 ℃, agingThe reaction time is 1h, and slurry is obtained;
filtering, washing and drying the slurry at 100 ℃ for 20 hours to obtain a filter cake; then roasting for 6h at 1100 ℃, crushing, tabletting and forming, reducing for 40h at 140 ℃ under 2MPa, drying and removing reducing water to obtain 1000g of a first-stage catalyst.
Preparation of a two-stage catalyst:
adding 6L of deionized water into a reaction kettle, then adding 123.25g of nano alumina with the particle size of 20-50nm to prepare nano oxide dispersion, wherein the temperature of the dispersion is 70 ℃;
weighing 2.08g of PdCl2、1.01g CoCl2·6H2O and 0.39g AgNO3Adding 148.35g of water, simultaneously dripping the obtained mixed salt aqueous solution and alkaline precipitator ammonia water into the nano oxide dispersion liquid for reaction at the reaction temperature of 90 ℃ for 3h, controlling the pH of the reaction system to be 8 in the reaction process, adding the alkaline precipitator after the dripping is finished to adjust the pH to 9, and then aging at the aging temperature of 95 ℃ for 1h to obtain slurry;
and filtering and washing the slurry, drying the slurry at 100 ℃ for 20h, roasting the slurry at 1100 ℃ for 6h, crushing the slurry, tabletting the slurry to form a sheet, reducing the sheet by using hydrogen at 140 ℃, keeping the absolute pressure of the sheet at 2MPa for 40h, and drying the sheet to remove reducing water to obtain 125g of a second-stage catalyst.
The first two-stage catalyst is a No. 5 catalyst combination.
Comparative example 1
First-stage catalyst preparation:
adding 48.9L of deionized water into a reaction kettle, then adding 997.5g of nano-alumina with the particle size of 20-50nm to prepare nano-oxide dispersion, wherein the temperature of the dispersion is 70 ℃;
weighing 5.41g Pd (NO)3)2Adding 265.22g of water, simultaneously adding the obtained solution and alkaline precipitator ammonia water into the nano oxide dispersion liquid for reaction at the reaction temperature of 90 ℃, dropwise adding for 3h, controlling the pH of the reaction system to be 8 in the reaction process, adding the alkaline precipitator after dropwise adding to adjust the pH to 9, then aging at the aging temperature of 95 ℃, and aging for 1h to obtain slurry;
filtering, washing and drying the slurry at 100 ℃ for 20 hours to obtain a filter cake; then roasting for 6h at 1100 ℃, crushing, tabletting and forming, reducing for 40h at 140 ℃ and 2MPa, and drying to remove reducing water to obtain 1000g of the catalyst.
Preparation of a two-stage catalyst:
adding 6.1L of deionized water into a reaction kettle, then adding 123.75g of nano alumina with the particle size of 20-50nm to prepare nano oxide dispersion, wherein the temperature of the dispersion is 70 ℃;
weighing 2.08g Pd (Cl)2Adding 102.06g of water, dripping the obtained solution and alkaline precipitator ammonia water into the nano oxide dispersion liquid simultaneously for reaction, wherein the reaction temperature is 90 ℃, the dripping time is 3 hours, the pH of a reaction system in the reaction process is controlled to be 8, after the dripping is finished, adding the alkaline precipitator to adjust the pH to 9, then aging, the aging temperature is 95 ℃, and the aging time is 1 hour, so as to obtain slurry;
and filtering and washing the slurry, drying the slurry at 100 ℃ for 20h, roasting the slurry at 1100 ℃ for 6h, crushing the slurry, tabletting the slurry to form a sheet, reducing the sheet by using hydrogen at 140 ℃, keeping the absolute pressure of the sheet at 2MPa for 40h, and drying the sheet to remove reducing water to obtain 125g of a second-stage catalyst.
The first two-stage catalyst is a No. 6 catalyst combination.
The contents of the components of catalyst combinations Nos. 1 to 6 are shown in Table 1 below
Contents of Components of catalyst combinations Nos. 11 to 6 in tables
Examples 6-10 below used the combination of hydrogenation catalysts No. 1-5 prepared in examples 1-5, respectively. Comparative example 2 the combination of hydrogenation catalysts No. 6 prepared in comparative example 1 was used.
Example 6
1) First stage hydrogenation
The method comprises the following steps of mixing a crude product of 2-ethyl-2-hexenal (containing 1 wt% of n-butyraldehyde, 96.0 wt% of 2-ethyl-2-hexenal, 1.8 wt% of butyraldehyde trimer and 1.2 wt% of 2-ethyl-2-hexenal dimer) with a feeding flow of 625g/h, feeding the mixture and a circulating reaction liquid of a part of an outlet of a first-stage hydrogenation reaction liquid and a circulating liquid of a heavy component of a rectification part into a first-stage reactor, mixing the first-stage hydrogenation reaction liquid, the circulating reaction liquid of the outlet of the first-stage hydrogenation reaction liquid and the circulating liquid of the heavy component of the rectification part into the first-stage reactor, wherein the temperature of the first-stage hydrogenation reaction is 100 ℃, the pressure is 3MPa, and the hydrogen flow rate is 1065L/h to obtain 13394.05g/h of an outlet material of the first-stage hydrogenation reactor, circulating the inlet material to a flow rate of 12746.71g/h, and feeding the rest material into a second-stage hydrogenation reactor.
2) Two-stage hydrogenation
The hydrogen after the first-stage hydrogenation flows into a second-stage hydrogenation reactor, the temperature of the second-stage hydrogenation reaction is 70 ℃, the reaction pressure is 3MPa, and the material flow rate at the outlet of the reactor is 638.77 g/h.
3) Rectification separation
In the step 2), the material at the outlet of the reactor enters a rectification system, the number of theoretical plates of the rectification is 20, the rectification pressure is 10kPa, the temperature of the tower bottom is 100 ℃, the flow of heavy components in the tower bottom is 15.46g/h, the flow of heavy components extracted as waste liquid is 0.191g/h, and the rest is circulated to the inlet of the first-stage hydrogenation reactor; the extraction temperature at the top of the 2-ethylhexanal tower is 90 ℃, and a 2-ethylhexanal product with the flow rate of 619.4g/h is obtained. The compositions of the respective substances were analyzed by gas chromatography.
Example 7
1) First stage hydrogenation
2-ethyl-2-hexenal crude product (containing 1.5 wt% of n-butyraldehyde, 95.7 wt% of 2-ethyl-2-hexenal, 1.3 wt% of butyraldehyde trimer and 1.5 wt% of 2-ethyl-2-hexenal dimer), feed flow 418g/h, and the mixture enters a first-stage reactor with circulating reaction liquid of the outlet part of the first-stage hydrogenation reaction liquid and circulating liquid of the heavy component of the rectification part, wherein the first-stage hydrogenation reaction temperature is 90 ℃, the pressure is 1.5MPa, and the hydrogen flow rate is 1420L/h, so that 13196.8g/h of the outlet material of the first-stage hydrogenation reactor is obtained, the outlet material is circulated to the inlet material flow rate of the first-stage reactor of 12771.09g/h, and the rest material enters a second-stage hydrogenation reactor.
2) Two-stage hydrogenation
The hydrogen after the first-stage hydrogenation flows into a second-stage hydrogenation reactor, the temperature of the second-stage hydrogenation reaction is 60 ℃, the reaction pressure is 1.5MPa, and the material flow rate at the outlet of the reactor is 426.49 g/h.
3) Rectification separation
In the step 2), the material at the outlet of the reactor enters a rectification system, the number of theoretical plates of rectification is 10, the rectification pressure is 20kPa, the temperature of a tower kettle is 140 ℃, the flow of heavy components in the tower kettle is 7.77g/h, the flow of heavy components extracted as waste liquid is 0.109g/h, and the rest is circulated to the inlet of a first-stage hydrogenation reactor; the extraction temperature at the top of the 2-ethylhexanal tower is 110 ℃, and a 2-ethylhexanal product is obtained, wherein the flow rate is 411.1 g/h. The compositions of the respective substances were analyzed by gas chromatography.
Example 8
1) First stage hydrogenation
The method comprises the following steps of mixing a 2-ethyl-2-hexenal crude product (containing 0.8 wt% of n-butyraldehyde, 95.9 wt% of 2-ethyl-2-hexenal, 2.0 wt% of butyraldehyde trimer and 1.3 wt% of 2-ethyl-2-hexenal dimer) with a feeding flow of 917.6g/h, feeding the mixture and a part of circulating reaction liquid at a first-stage hydrogenation reaction liquid outlet and a part of circulating liquid of heavy components at a rectification part into a first-stage reactor, mixing the first-stage hydrogenation reaction liquid with the circulating reaction liquid at a temperature of 110 ℃, the pressure of 4.5MPa and the hydrogen flow rate of 2343L/h to obtain a first-stage hydrogenation reactor outlet material of 24249.1g/h, circulating the mixture to a first-stage reactor inlet material flow rate of 23316.44g/h, and feeding the rest material into a second-stage hydrogenation reactor.
2) Two-stage hydrogenation
The hydrogen after the first-stage hydrogenation flows into a second-stage hydrogenation reactor, the temperature of the second-stage hydrogenation reaction is 80 ℃, the reaction pressure is 4.5MPa, and the material flow rate at the outlet of the reactor is 934.05 g/h.
3) Rectification separation
The material at the outlet of the reactor in the step 2) enters a rectification system, the number of theoretical plates of rectification is 30, the rectification pressure is 30kPa, the temperature of a tower kettle is 150 ℃, the flow of heavy components in the tower kettle is 11.99g/h, the flow of heavy components extracted as waste liquid is 0.132g/h, and the rest is circulated to the inlet of a first-stage hydrogenation reactor; the temperature of the 2-ethylhexanal extracted from the top of the tower is 122 ℃, and a 2-ethylhexanal product is obtained, wherein the flow rate is 912.9 g/h. The compositions of the respective substances were analyzed by gas chromatography.
Example 9
1) First stage hydrogenation
2-ethyl-2-hexenal crude product (containing 1.4 wt% of n-butyraldehyde, 95.9 wt% of 2-ethyl-2-hexenal, 1.2 wt% of butyraldehyde trimer and 1.5 wt% of 2-ethyl-2-hexenal dimer), the feed flow is 139g/h, the crude product is mixed with the circulating reaction liquid of the outlet part of the first-stage hydrogenation reaction liquid and the circulating liquid of the heavy component of the rectification part and enters a first-stage reactor, the temperature of the first-stage hydrogenation reaction is 80 ℃, the pressure is 1MPa, the hydrogen flow rate is 120L/h, 1552.82g/h of the outlet material of the first-stage hydrogenation reactor is obtained, the outlet material is circulated to the inlet material flow rate of the first-stage reactor of 1411.65g/h, and the rest material enters a second-stage hydrogenation reactor.
2) Two-stage hydrogenation
The hydrogen after the first-stage hydrogenation flows into a second-stage hydrogenation reactor, the temperature of the second-stage hydrogenation reaction is 50 ℃, the reaction pressure is 1MPa, and the material flow rate at the outlet of the reactor is 141.33 g/h.
3) Rectification separation
The material at the outlet of the reactor in the step 2) enters a rectification system, the number of theoretical plates of the rectification is 15, the rectification pressure is 20kPa, the temperature of the tower bottom is 140 ℃, the flow of heavy components in the tower bottom is 0.94g/h, the flow of heavy components extracted as waste liquid is 0.015g/h, and the rest is circulated to the inlet of the first-stage hydrogenation reactor; the extraction temperature at the top of the 2-ethylhexanal tower is 110 ℃, and a 2-ethylhexanal product is obtained, wherein the flow rate is 137.4 g/h. The compositions of the respective substances were analyzed by gas chromatography.
Example 10
1) First stage hydrogenation
The method comprises the following steps of mixing a crude product of 2-ethyl-2-hexenal (containing 0.5 wt% of n-butyraldehyde, 96.0 wt% of 2-ethyl-2-hexenal, 2.5 wt% of butyraldehyde trimer and 1.0 wt% of 2-ethyl-2-hexenal dimer), feeding the mixture at a feed flow rate of 1171.9g/h, mixing the mixture with a part of circulating reaction liquid at a first-stage hydrogenation reaction liquid outlet and a part of circulating liquid of heavy components at a rectification part, feeding the mixture into a first-stage reactor, carrying out first-stage hydrogenation reaction at a temperature of 120 ℃, carrying out pressure of 5MPa and a hydrogen flow rate of 4991L/h to obtain a first-stage hydrogenation reactor outlet material of 49011.3g/h, circulating the mixture to a first-stage reactor inlet material flow rate of 47815.9g/h, and feeding the rest material into a second-stage hydrogenation reactor.
2) Two-stage hydrogenation
The hydrogen after the first-stage hydrogenation flows into a second-stage hydrogenation reactor, the temperature of the second-stage hydrogenation reaction is 90 ℃, the reaction pressure is 5MPa, and the material flow rate at the outlet of the reactor is 1197.02 g/h.
3) Rectification separation
The material at the outlet of the reactor in the step 2) enters a rectification system, the number of theoretical plates of the rectification is 25, the rectification pressure is 20kPa, the temperature of the tower bottom is 140 ℃, the flow of heavy components in the tower bottom is 24.69g/h, the flow of heavy components extracted as waste liquid is 0.244g/h, and the rest is circulated to the inlet of the first-stage hydrogenation reactor; the temperature of the 2-ethylhexanal extracted from the top of the tower is 110 ℃, and a 2-ethylhexanal product is obtained, wherein the flow rate is 1167.5 g/h. The compositions of the respective substances were analyzed by gas chromatography.
Comparative example 2
1) First stage hydrogenation
The method comprises the following steps of mixing a crude product of 2-ethyl-2-hexenal (containing 0.5 wt% of n-butyraldehyde, 96.0 wt% of 2-ethyl-2-hexenal, 2.5 wt% of butyraldehyde trimer and 1.0 wt% of 2-ethyl-2-hexenal dimer) with 1171.9g/h of feeding flow rate, mixing the crude product with a part of circulating reaction liquid at a first-stage hydrogenation reaction liquid outlet, feeding the mixture into a first-stage reactor, and circulating the mixture to a first-stage reactor inlet material flow rate of 50133.53g/h at the first-stage hydrogenation reaction temperature of 120 ℃, the pressure of 5MPa and the hydrogen flow rate of 4991L/h to obtain a first-stage hydrogenation reactor outlet material of 51386.87g/h, and feeding the rest material into a second-stage hydrogenation reactor.
2) Two-stage hydrogenation
The hydrogen after the first-stage hydrogenation flows into a second-stage hydrogenation reactor, the temperature of the second-stage hydrogenation reaction is 90 ℃, the reaction pressure is 5MPa, and the material flow rate at the outlet of the reactor is 1258.52 g/h.
3) Rectification separation
In the step 2), the material at the outlet of the reactor enters a rectification system, the number of theoretical plates for rectification is 25, the rectification pressure is 20kPa, the temperature of a tower kettle is 140 ℃, the flow of heavy components in the tower kettle is 274.82g/h, and no circulation exists; the temperature of the 2-ethylhexanal extracted from the top of the tower is 110 ℃, and a 2-ethylhexanal product is obtained, wherein the flow rate is 976.36 g/h. The compositions of the respective substances were analyzed by gas chromatography.
The compositions and mass contents of the outlets of the two-stage hydrogenation reactors of examples 6 to 10 and comparative example 2 are shown in Table 2 below
TABLE 2 two-stage hydrogenation reactor outlet composition
As can be seen from table 2, the contents of butyraldehyde trimer, 2-ethyl-2-hexenal dimer, 2-ethylhexanal dimer and 2-ethylhexanal and 2-ethyl-2-hexenal polymer in the hydrogenation reaction liquids in examples 6 to 10 are much smaller than that in comparative example 2, which indicates that the catalysts and processes in examples 6 to 10 have significant decomposition effect on the aldehyde polymer, and the yield of 2-ethylhexanal is improved; meanwhile, the contents of the excessive hydrogenation byproduct 2-ethylhexanol in the examples 6-10 are much smaller than that in the comparative example 2, which shows that the catalysts and the processes in the examples 6-10 have obvious effect on reducing the 2-ethylhexanol byproduct. Due to the beneficial effects of the examples 6-10, the content of the 2-ethylhexanal in the reaction liquid is obviously improved, so that the waste liquid amount after rectification and separation is obviously reduced, and the product yield is greatly improved.
Claims (12)
1. A process for preparing 2-ethylhexanal, comprising the steps of:
1) in a first-stage reactor, carrying out a first-stage hydrogenation reaction on a 2-ethyl-2-hexenal raw material and hydrogen under the catalysis of a first-stage catalyst to obtain a first-stage hydrogenation solution;
2) part of the first-stage hydrogenated liquid obtained in the step 1) enters a second-stage reactor, and is subjected to second-stage hydrogenation reaction with hydrogen under the catalysis of a second-stage catalyst to obtain second-stage hydrogenated liquid; circulating the rest part of the first-stage hydrogenation liquid obtained in the step 1) to a first-stage reactor for circulating hydrogenation;
3) rectifying and separating the second-stage hydrogenated liquid in the step 2) to obtain a 2-ethylhexanal product, heavy components and light components, wherein one part of the heavy components is recycled to the first-stage reactor for cyclic hydrogenation, and the rest of the heavy components is discharged as waste liquid;
the first-stage catalyst is a supported catalyst containing Pd, Pt, Cu and Ni; the two-stage catalyst is a supported catalyst containing Pd, Co and Ag.
2. The method according to claim 1, wherein the one-stage catalyst has a Pd content of 0.05-0.5% by mass based on the total mass of the catalyst; the Pt content is 0.01-0.1%; the Cu content is 0.01-0.1%; ni content of 0.01-0.1%; 99.2 to 99.92 percent of carrier.
3. The method according to claim 1, wherein the one-stage catalyst has a Pd content of 0.08-0.3% by mass based on the total mass of the catalyst; the Pt content is 0.02-0.1%; the Cu content is 0.02-0.1%; the Ni content is 0.02-0.1%; 99.45 to 99.86 percent of carrier.
4. The method according to claim 1, wherein the two-stage catalyst has a Pd content of 0.5-1% by mass based on the total mass of the catalyst; the content of Co is 0.02-0.2%; the content of Ag is 0.02-0.2%; 98.6-99.46% of carrier.
5. The method according to claim 1, wherein the two-stage catalyst has a Pd content of 0.6-0.8% by mass based on the total mass of the catalyst; the content of Co is 0.06-0.16%; the Ag content is 0.06-0.16%; 98.88 to 99.28 percent of carrier.
6. The method according to claim 1, wherein the 2-ethyl-2-hexenal raw material is n-butyraldehyde, and the reaction solution containing 2-ethyl-2-hexenal is obtained by condensation and dehydration, and the composition of the reaction solution containing 2-ethyl-2-hexenal comprises: 0.5-1.5 wt% of n-butyraldehyde, 95-97 wt% of 2-ethyl-2-hexenal, 1-2.5 wt% of butyraldehyde trimer and 1-1.5 wt% of 2-ethyl-2-hexenal dimer.
7. The method according to claim 1, wherein in the step 1), the temperature of the first-stage hydrogenation reaction is 80-120 ℃, and the absolute pressure is 1-5 MPa; in the step 2), the temperature of the second-stage hydrogenation reaction is 50-90 ℃, and the absolute pressure is 1-5 MPa.
8. The method of claim 1, wherein the mass ratio of the first-stage catalyst to the second-stage catalyst is 1-10: 1.
9. The method according to claim 1, wherein in the step 2), the circulation ratio of the first-stage hydrogenation liquid is 10-40: 1.
10. The method of claim 1, wherein the recycle ratio of the heavy component in step 3) is 60-100: 1.
11. The process according to claim 1, wherein the total liquid hourly space velocity is in the range of from 0.1 to 1h-1。
12. The method of claim 1, wherein in step 1), the molar ratio of hydrogen to 2-ethyl-2-hexenal is 5-25: 1.
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Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5756856A (en) * | 1995-07-08 | 1998-05-26 | Huels Aktiengesellschaft | Process for the preparation of 2-ethylhexanal |
| CN1569789A (en) * | 2003-07-11 | 2005-01-26 | 中国石油化工股份有限公司齐鲁分公司 | Process for the preparation of 2-ethylhexanal |
| CN101759533A (en) * | 2008-11-18 | 2010-06-30 | 熊长宏 | New method for synthesizing 2-ethylhexanal |
| CN102249854A (en) * | 2011-07-06 | 2011-11-23 | 上海焦化有限公司 | Two-step-method hydrogenation process for preparing neopentyl glycol |
| CN107930647A (en) * | 2017-12-06 | 2018-04-20 | 万华化学集团股份有限公司 | A kind of preparation method of catalyst, its preparation method and 2 ethyl hexanals |
-
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Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5756856A (en) * | 1995-07-08 | 1998-05-26 | Huels Aktiengesellschaft | Process for the preparation of 2-ethylhexanal |
| CN1569789A (en) * | 2003-07-11 | 2005-01-26 | 中国石油化工股份有限公司齐鲁分公司 | Process for the preparation of 2-ethylhexanal |
| CN101759533A (en) * | 2008-11-18 | 2010-06-30 | 熊长宏 | New method for synthesizing 2-ethylhexanal |
| CN102249854A (en) * | 2011-07-06 | 2011-11-23 | 上海焦化有限公司 | Two-step-method hydrogenation process for preparing neopentyl glycol |
| CN107930647A (en) * | 2017-12-06 | 2018-04-20 | 万华化学集团股份有限公司 | A kind of preparation method of catalyst, its preparation method and 2 ethyl hexanals |
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