CN109748791B - Energy-saving method for producing dimethyl adipate - Google Patents
Energy-saving method for producing dimethyl adipate Download PDFInfo
- Publication number
- CN109748791B CN109748791B CN201711058562.1A CN201711058562A CN109748791B CN 109748791 B CN109748791 B CN 109748791B CN 201711058562 A CN201711058562 A CN 201711058562A CN 109748791 B CN109748791 B CN 109748791B
- Authority
- CN
- China
- Prior art keywords
- esterification
- methanol
- reaction
- rectifying tower
- tower
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Images
Abstract
The invention aims to provide an energy-saving method for producing dimethyl adipate, which takes methanol and molten adipic acid as raw materials, adopts a continuous stirring type reaction kettle and an esterification reaction rectifying tower to carry out primary and secondary esterification reaction, and directly sends gas phase at the top of the esterification reaction rectifying tower into a methanol recovery tower without cooling; removing light component impurities such as dimethyl ether and the like from the top of the methanol recovery tower, removing heavy component impurities such as water and the like from the bottom of the methanol recovery tower, extracting liquid-phase methanol from a side line, mixing a part of the liquid-phase methanol with fresh methanol to be used as reflux liquid of an esterification rectifying tower, so that the reflux quantity of the esterification rectifying tower is reduced, and circulating a part of the liquid-phase methanol to a first-stage esterification to be used as reaction liquid; methanol is gasified and removed heat in the continuous stirring type reaction kettle, methanol is used as a heat removing medium in a jacket, methanol steam is used as a feed of an esterification rectifying tower, and ester products can be directly used as products without purification or sent to a hydrogenation unit to produce the 1, 6-hexanediol. The method has the advantages of high conversion rate, good selectivity, high purity and low energy consumption.
Description
Technical Field
The invention relates to an energy-saving method for producing dimethyl adipate, which combines pre-esterification and continuous esterification to produce the dimethyl adipate.
Background
Dimethyl adipate is a high boiling, colorless, transparent liquid, readily soluble in alcohols and ethers, but insoluble in water. It is an important solvent which is difficult to volatilize, and is widely used in products such as high-grade paint, synthetic resin, cleaning agent, printing ink and the like. As an excellent cold-resistant plasticizer, the low-temperature soft rubber can endow the product with excellent low-temperature soft performance, and has certain photo-thermal stability and water resistance. Has wide application in solvent, medicine and perfume synthesis, paper making and cellulose resin production. In addition, dimethyl adipate is also an intermediate for synthesizing 1, 6-hexanediol.
Because concentrated sulfuric acid has dehydration and oxidation effects, the traditional process for synthesizing dimethyl adipate adopts concentrated sulfuric acid as a catalyst, but causes the problems of more side reactions, equipment corrosion and three-waste pollution, which cause high equipment investment and three-waste treatment cost. In order to overcome the defects of the concentrated sulfuric acid method, researches on using hydrated sodium bisulfate, p-toluenesulfonic acid, heteropoly acid, solid superacid and the like as esterification catalysts are reported in recent years, and a better esterification effect is obtained; but also has the defects of difficult recovery and reuse of the catalyst, difficult preparation, difficult purification of the product, great industrialization difficulty and the like. The strong acid cation exchange resin has the advantages of small volume affected by solvent, easy realization of continuous production and the like, and simultaneously has mild reaction conditions, and is easy to separate and reuse from a reaction system, thereby having better industrial application prospect.
At present, the demand for dimethyl adipate in foreign countries is continuously rising, and the demand in domestic is not very large, but has a certain rising trend.
Adipic acid reacts with methanol to produce dimethyl adipate and water, which is a reversible reaction. And when the reaction reaches the equilibrium, the conversion rate of the acid is not changed, and the conversion rate of the adipic acid batch esterification reaction is far lower than 100 percent. In addition, in large-scale industrial production, the intermittent operation is discontinuous in material feeding and discharging, and technological parameters are continuously fluctuated in the production process. In order to greatly increase the conversion rate of acid, the main operation schemes are as follows: and continuously replenishing methanol to the system to increase the ratio of alcohol to acid and promote the conversion of acid. However, the method has the disadvantages of large methanol circulation amount, large loss, high energy consumption of subsequent separation and low economy. In another scheme, the water in the reaction solution is continuously discharged to promote the reaction to proceed to the right, so that the reaction is completed. At present, the scheme has more researches and various means. Water is taken out by a water-carrying agent (cyclohexane, toluene and the like) through a water separator, and methanol and the water-carrying agent flow back to the reactor. The method is more applied in general laboratory scientific research, but the industrial high-purity product obtained still needs to face the separation problem of a large amount of water-carrying agents, and the energy consumption is higher. Patent GB143069 discloses a more primitive process using concentrated sulfuric acid as catalyst and a tank reactor reactive distillation to remove water. The dimethyl adipate is produced by taking sulfuric acid or other inorganic liquid acid as a catalyst, and the inorganic liquid acid is taken as the catalyst, so that the problems of corrosion of the inorganic liquid acid to equipment, three-waste treatment of reaction products and the like, and environmental pollution exist. The patent W09008127 discloses the inside of a tubular reactor divided into a plurality of beds, a solid catalyst is loosely arranged in the beds, alcohol vapor is contacted with acid and the solid catalyst in an acid solution in a bubbling mode, and the reaction is carried out under certain pressure. The reactor is divided into a plurality of beds, and the catalyst is loosely arranged in the beds, so that the catalyst is inconvenient to fill. Patent CN200410020789.3 discloses a method for producing 1, 6-hexanediol, which involves the synthesis of dimethyl adipate. Adipic acid and methanol are introduced from the lower end of a tower-type esterification reactor according to a certain weight ratio, a self-made catalyst loaded with activated carbon is filled in the reactor, and dimethyl adipate, water and a mixture of the unreacted adipic acid and the methanol which are generated by the reaction flow out from the upper end of the esterification reactor; then the effluent is rectified to obtain high-purity adipic acid dimethyl ester. The process flow is complex, the catalyst preparation cost is high, and the method is not suitable for industrial production. Patent CN200920110006.9 discloses a device for producing dimethyl adipate by pervaporation-reaction coupling. The device consists of a reactor, a pervaporation membrane, a delivery pump and a cold trap. The top of the reactor is provided with a raw material inlet, a methanol inlet and a reaction liquid outlet. The reaction liquid outlet is connected with a delivery pump to the feed liquid inlet of the pervaporation membrane, and the side outlet of the pervaporation membrane is connected with the methanol inlet. The permeation side of the pervaporation membrane is connected with the input end of a U-shaped pipe in the cold well and is connected with a vacuum pump. Although the device can improve the conversion rate and reduce the energy consumption, the used membrane component has higher cost. CN103342642 adopts three reaction kettles connected in parallel and a rectifying tower combined, methanol and water in the reaction system are evaporated out while the reaction is carried out, steam is separated and purified by the rectifying tower, moisture is discharged from the tower kettle, methanol returns to the reaction kettle from the tower top, the moisture is continuously carried out of the reaction system, and the esterification reaction finally tends to be complete. The method has the advantages of long reaction time, difficult control and high energy consumption.
Disclosure of Invention
The invention aims to provide an energy-saving method for producing dimethyl adipate, which solves the problems of low acid conversion rate, high energy consumption, low productivity, serious pollution and the like in the prior art. The process of the invention enables the production process of dimethyl adipate to be simpler, the conversion rate to be high, the yield to be high and the pollution to be less. In order to make the conversion rate of the adipic acid approach 100%, the continuous esterification technology is adopted to greatly improve the conversion rate of the adipic acid limited by thermodynamic equilibrium in the batch esterification technology.
The invention can solve the problems in the prior art by generating a first-stage esterification reaction in a continuous stirring type reaction kettle, leading the product of the first-stage esterification reaction to be in countercurrent contact with methanol on a tower plate carrying a catalyst in an esterification rectifying tower to generate a second-stage esterification reaction, leading dimethyl adipate to be capable of carrying out hydrogenation reaction without purification to obtain 1, 6-hexanediol, and leading the gas phase at the top of the esterification rectifying tower containing dimethyl ether to directly enter a methanol recovery tower.
In order to solve the technical problems, the technical scheme of the invention is as follows: an energy-saving method for producing dimethyl adipate comprises the following steps:
(1) adding methanol and molten adipic acid into a continuous stirring type reaction kettle to perform primary esterification reaction; the reaction temperature is 80-120 ℃, and the reaction pressure is 0.02-0.2 MPaG;
(2) feeding the reaction kettle liquid from the upper part of an esterification rectifying tower, feeding methanol from the lower part of the esterification rectifying tower, carrying out secondary esterification, directly feeding the gas phase at the top of the tower containing dimethyl ether into a methanol recovery tower, and controlling the temperature of the reaction section of the esterification rectifying tower to be 80-120 ℃;
(3) the methanol recovery tower extracts noncondensable gas containing dimethyl ether and liquid phase containing light components from the top, the side-line liquid phase extracts methanol, the methanol for removing water and light component impurities is divided into two parts, one part of methanol is used as reflux liquid of the esterification rectifying tower, the purified methanol is used as reflux liquid, the reflux ratio can be reduced, the energy consumption is reduced, one part of methanol is circulated to the first stage of esterification to be used as reaction liquid, and heavy components containing water are extracted from the tower bottom.
(4) The method comprises the steps of heating methanol in a continuous stirring type reaction kettle by gasification, wherein a reactant methanol in a system is used as a heating medium for a jacket, methanol steam is used as a feeding material of an esterification reaction rectifying tower, a gas phase at the top of the esterification reaction rectifying tower is directly used as a feeding material of a methanol recovery tower without condensation, and an ester product can be directly used as a product or sent into a hydrogenation unit to produce 1, 6-hexanediol without purification.
The continuous stirring type reaction kettle has 2 reaction kettles, is operated intermittently, is connected to the esterification rectifying tower in a material discharging switching mode, and can realize continuous production and fully recover reaction heat.
The molar ratio of methanol to adipic acid in the reaction kettle is 2-6: 1, preferably 3-5: 1; the reaction time is 3 to 8 hours, preferably 4 to 6 hours.
The reaction kettle is filled with strong-acid cation exchange resin, the dosage of the resin is 1-8% (strong acid resin/adipic acid), and the preferred dosage is 3-5%.
Stirring speed has great influence to the heat transfer of matter in the reation kettle, and the rotational speed increases can accelerate reaction rate, but can increase the resin breakage, and suitable rotational speed is 100 ~ 400r/min, preferably 200 ~ 300 r/min.
The esterification rectifying tower and the methanol recovery tower both adopt high-efficiency low-resistance fillers at the upper parts and adopt plate towers at the lower parts, wherein the plate towers are arranged at the lower parts of the esterification rectifying tower, so that the liquid holdup of the tower plates is increased, the reaction residence time is prolonged, and the catalyst is convenient to replace. If the lower reaction section adopts a packed tower, the catalyst is inconvenient to replace, and the device must be stopped when the catalyst is replaced.
The catalyst at the reaction section of the esterification rectifying tower is suspended in a layer on a plate pad, and any layer of catalyst can be taken out and replaced without influencing the operation of the esterification rectifying tower.
The esterification reaction rectifying tower has the advantages that the upper rectifying section is filled with the filler, so that the lower catalyst particles are prevented from rising and mixing into gas phase blocking equipment and pipelines, the catalyst particles are packaged in the metal filler cage, the catalyst can also be prevented from rising and mixing into the gas phase blocking equipment and pipelines, the bed pressure drop can be reduced, monoester entrained in the gas phase is effectively intercepted and reacted, the amount of the gas phase entrained monoester is low, and the service life of the catalyst is long.
The tower top pressure of the esterification rectifying tower is 0.02-0.6 MPaG, and preferably 0.04-0.2 MPaG; the tower bottom component is mainly dimethyl adipate, and the tower bottom temperature is 90-210 ℃, preferably 150-195 ℃ in order to prevent high-temperature coking or decomposition.
The liquid volume space-time rate of the esterification rectifying tower is 0.2-0.6 h-1。
The purity of the adipic acid dimethyl ester product at the bottom of the esterification rectifying tower is more than or equal to 99.5 percent, the acid value of the adipic acid dimethyl ester product is less than or equal to 0.5mgKOH/g, the product can be directly sold for the outside, and the product can also be hydrogenated to produce a 1, 6-hexanediol product.
The method is suitable for producing diethyl adipate, diisooctyl adipate, dibutyl adipate and dimethyl succinate.
By adopting the technical scheme of the invention, methanol and molten adipic acid are added into a continuous stirring type reaction kettle to generate a first-stage esterification reaction; the reaction temperature is 80-120 ℃, and the reaction pressure is 0.02-0.2 MpaG; the temperature of the reaction section of the esterification reaction rectifying tower is 80-120 ℃; 2 continuous stirring type reaction kettles are intermittently operated; the molar ratio of methanol to adipic acid in the reaction kettle is 2-6: 1, preferably 3-5: 1; the reaction time is 3-8 hours, preferably 4-6 hours; the reaction kettle is filled with strong-acid cation exchange resin, the dosage of the resin is 1-8% (strong-acid resin/adipic acid), and the preferred dosage is 3-5%; the rotating speed in the reaction kettle is 100-400 r/min, preferably 200-300 r/min; the tower top pressure of the esterification rectifying tower is 0.02-0.6 MPaG, and preferably 0.04-0.2 MPaG; the components in the tower bottom are mainly dimethyl adipate, the temperature in the tower bottom is 90-210 ℃, and preferably 150-195 ℃, thereby obtaining good technical effect.
Drawings
FIG. 1 is a schematic process flow diagram of the present invention.
In the figure: r1 is a continuous stirring type reaction kettle, T1 is an esterification rectifying tower, T2 is a methanol recovery tower, E1 is a T1 tower bottom discharge cooler, E2 is a T2 tower top condenser, F1 is a T1 tower bottom discharge filter, and D1 is a T2 tower top reflux tank.
Recycling the circulating methanol 3 and adding the molten adipic acid 1 into a continuous stirring type reaction kettle R1 to perform a first-stage esterification reaction, wherein the reaction temperature is 80-120 ℃, and the reaction pressure is 0.02-0.2 MPaG; feeding the reaction kettle liquid 7 from the upper part of an esterification rectifying tower T1, mixing a continuously stirred reaction kettle R1 methanol steam 5 with heat-removing methanol 6, then feeding from the lower part of T1, carrying out secondary esterification reaction, directly feeding the top gas phase 11 containing dimethyl ether into a methanol recovery tower T2, wherein the temperature of the reaction section of the esterification rectifying tower T1 is 80-150 ℃; the top of a methanol recovery tower T2 contains dimethyl ether gas phase 15 as noncondensable gas to be extracted, a small amount of light components 8 are extracted from the top of the tower, methanol 17 is extracted and recovered from a side liquid phase, methanol for dehydrating and removing light component impurities is divided into two parts, one part of methanol 19 and fresh methanol 2 are mixed and then used as reflux liquid of an esterification rectifying tower, one part of methanol 18 is circulated to first-stage esterification to be used as reaction liquid, and heavy components 12 mainly containing water are extracted from a tower kettle; methanol in a continuous stirring type reaction kettle R1 is gasified and removed with heat, a jacket adopts methanol 4 as a heat removal medium, methanol steam 6 as a feed of an esterification reaction rectifying tower, a gas phase 11 at the top of the esterification reaction rectifying tower is directly used as a feed of a methanol recovery tower without condensation, an ester product 9 is cooled by a T1 tower kettle discharge cooler and then enters a T1 tower kettle discharge filter for filtration, and the product can be sold as a product 10 or sent to a hydrogenation unit for producing 1, 6-hexanediol without purification.
The invention is further illustrated by the following examples.
Detailed Description
[ example 1 ]
This embodiment is described with reference to fig. 1 and the drawings.
Performing primary esterification reaction in a continuous stirring type reaction kettle at the reaction temperature of 90 ℃ and the reaction pressure of 0.04 MPaG; the number of the continuous stirring type reaction kettles is 2, the batch operation is carried out, the discharging is switched and connected to the esterification rectifying tower, and the continuous production and the full recovery of reaction heat can be realized.
The molar ratio of methanol to adipic acid in the reaction kettle is 4: 1; the reaction time was 4 hours.
The reaction kettle is filled with strong acid cation exchange resin, and the dosage of the resin is 3 percent (strong acid resin/adipic acid).
The stirring speed in the reaction kettle is 200 r/min.
The tower top pressure of the esterification rectifying tower is 0.04 MPaG; the tower bottom component is mainly dimethyl adipate, and the temperature of the tower bottom is 175 ℃ in order to prevent the dimethyl adipate from coking or decomposing at high temperature.
The estersThe liquid volume space-time rate of the chemical reaction rectifying tower is 0.3h-1。
The purity of the adipic acid dimethyl ester product at the bottom of the esterification rectifying tower is 99.50 percent, the acid value of the adipic acid dimethyl ester is 0.5mgKOH/g, the adipic acid dimethyl ester product can be directly sold as a product, and the product can also be hydrogenated to produce a 1, 6-hexanediol product.
[ example 2 ]
This embodiment is described with reference to fig. 1 and the drawings.
Performing primary esterification reaction in a continuous stirring type reaction kettle at the reaction temperature of 90 ℃ and the reaction pressure of 0.04 MPaG; the number of the continuous stirring type reaction kettles is 2, the batch operation is carried out, the discharging is switched and connected to the esterification rectifying tower, and the continuous production and the full recovery of reaction heat can be realized.
The molar ratio of methanol to adipic acid in the reaction kettle is 4: 1; the reaction time was 4 hours.
The reaction kettle is filled with strong acid cation exchange resin, and the dosage of the resin is 3 percent (strong acid resin/adipic acid).
The stirring speed in the reaction kettle is 200 r/min.
The tower top pressure of the esterification rectifying tower is 0.04 MPaG; the tower bottom component is mainly dimethyl adipate, and the temperature of the tower bottom is 175 ℃ in order to prevent the dimethyl adipate from coking or decomposing at high temperature.
The liquid volume space-time rate of the esterification rectifying tower is 0.35h-1。
The purity of the adipic acid dimethyl ester product at the bottom of the esterification rectifying tower is 99.50 percent, the acid value of the adipic acid dimethyl ester is 0.5mgKOH/g, the adipic acid dimethyl ester product can be directly sold as a product, and the product can also be hydrogenated to produce a 1, 6-hexanediol product.
[ example 3 ]
This embodiment is described with reference to fig. 1 and the drawings.
Performing primary esterification reaction in a continuous stirring type reaction kettle at the reaction temperature of 90 ℃ and the reaction pressure of 0.04 MPaG; the number of the continuous stirring type reaction kettles is 2, the batch operation is carried out, the discharging is switched and connected to the esterification rectifying tower, and the continuous production and the full recovery of reaction heat can be realized.
The molar ratio of methanol to adipic acid in the reaction kettle is 4: 1; the reaction time was 5 hours.
The reaction kettle is filled with strong acid cation exchange resin, and the dosage of the resin is 3 percent (strong acid resin/adipic acid).
The stirring speed in the reaction kettle is 200 r/min.
The tower top pressure of the esterification rectifying tower is 0.04 MPaG; the tower bottom component is mainly dimethyl adipate, and the temperature of the tower bottom is 175 ℃ in order to prevent the dimethyl adipate from coking or decomposing at high temperature.
The liquid volume space-time rate of the esterification rectifying tower is 0.3h-1。
The purity of the adipic acid dimethyl ester product at the bottom of the esterification rectifying tower is 99.55 percent, the acid value of the adipic acid dimethyl ester is 0.4mgKOH/g, the adipic acid dimethyl ester product can be directly sold as a product, and the product can also be hydrogenated to produce a 1, 6-hexanediol product.
[ example 4 ]
This embodiment is described with reference to fig. 1 and the drawings.
Performing primary esterification reaction in a continuous stirring type reaction kettle at the reaction temperature of 90 ℃ and the reaction pressure of 0.04 MPaG; the number of the continuous stirring type reaction kettles is 2, the batch operation is carried out, the discharging is switched and connected to the esterification rectifying tower, and the continuous production and the full recovery of reaction heat can be realized.
The molar ratio of methanol to adipic acid in the reaction kettle is 4: 1; the reaction time was 4 hours.
The reaction kettle is filled with strong acid cation exchange resin, and the dosage of the resin is 4 percent (strong acid resin/adipic acid).
The stirring speed in the reaction kettle is 200 r/min.
The tower top pressure of the esterification rectifying tower is 0.04 MPaG; the tower bottom component is mainly dimethyl adipate, and the temperature of the tower bottom is 175 ℃ in order to prevent the dimethyl adipate from coking or decomposing at high temperature.
The liquid volume space-time rate of the esterification rectifying tower is 0.3h-1。
The purity of the adipic acid dimethyl ester product at the bottom of the esterification rectifying tower is 99.50 percent, the acid value of the adipic acid dimethyl ester is 0.35mgKOH/g, the adipic acid dimethyl ester product can be directly sold as a product, and the product can also be hydrogenated to produce a 1, 6-hexanediol product.
[ example 5 ]
This embodiment is described with reference to fig. 1 and the drawings.
Performing primary esterification reaction in a continuous stirring type reaction kettle at the reaction temperature of 100 ℃ and the reaction pressure of 0.08 MPaG; the number of the continuous stirring type reaction kettles is 2, the batch operation is carried out, the discharging is switched and connected to the esterification rectifying tower, and the continuous production and the full recovery of reaction heat can be realized.
The molar ratio of methanol to adipic acid in the reaction kettle is 5: 1; the reaction time was 5 hours.
The reaction kettle is filled with strong acid cation exchange resin, and the dosage of the resin is 4 percent (strong acid resin/adipic acid).
The stirring speed in the reaction kettle is 250 r/min.
The top pressure of the esterification rectifying tower is 0.06 MPaG; the tower bottom component is mainly dimethyl adipate, and the temperature of the tower bottom is 182 ℃ in order to prevent the dimethyl adipate from coking or decomposing at high temperature.
The liquid volume space-time rate of the esterification rectifying tower is 0.4h-1。
The purity of the adipic acid dimethyl ester product at the bottom of the esterification rectifying tower is 99.65 percent, the acid value of the adipic acid dimethyl ester is 0.3mgKOH/g, the adipic acid dimethyl ester product can be directly sold as a product, and the product can also be hydrogenated to produce a 1, 6-hexanediol product.
[ example 6 ]
This embodiment is described with reference to fig. 1 and the drawings.
Performing primary esterification reaction in a continuous stirring type reaction kettle at the reaction temperature of 110 ℃ and the reaction pressure of 0.10 MPaG; the number of the continuous stirring type reaction kettles is 2, the batch operation is carried out, the discharging is switched and connected to the esterification rectifying tower, and the continuous production and the full recovery of reaction heat can be realized.
The molar ratio of methanol to adipic acid in the reaction kettle is 6: 1; the reaction time was 6 hours.
The reaction kettle is filled with strong acid cation exchange resin, and the dosage of the resin is 5 percent (strong acid resin/adipic acid).
The stirring speed in the reaction kettle is 300 r/min.
The tower top pressure of the esterification rectifying tower is 0.08 MPaG; the tower bottom component is mainly dimethyl adipate, and the temperature of the tower bottom is 188 ℃ in order to prevent the dimethyl adipate from coking or decomposing at high temperature.
The liquid volume space-time rate of the esterification rectifying tower is 0.5h-1。
The purity of the adipic acid dimethyl ester product at the bottom of the esterification rectifying tower is 99.70 percent, the acid value of the adipic acid dimethyl ester is 0.25mgKOH/g, the adipic acid dimethyl ester product can be directly sold as a product, and the product can also be hydrogenated to produce a 1, 6-hexanediol product.
[ example 7 ]
This embodiment is described with reference to fig. 1 and the drawings.
Performing primary esterification reaction in a continuous stirring type reaction kettle at the reaction temperature of 90 ℃ and the reaction pressure of 0.04 MPaG; the number of the continuous stirring type reaction kettles is 2, the batch operation is carried out, the discharging is switched and connected to the esterification rectifying tower, and the continuous production and the full recovery of reaction heat can be realized.
The molar ratio of methanol to adipic acid in the reaction kettle is 4: 1; the reaction time was 5 hours.
The reaction kettle is filled with strong acid cation exchange resin, and the dosage of the resin is 5 percent (strong acid resin/adipic acid).
The stirring speed in the reaction kettle is 200 r/min.
The tower top pressure of the esterification rectifying tower is 0.04 MPaG; the tower bottom component is mainly dimethyl adipate, and the temperature of the tower bottom is 175 ℃ in order to prevent the dimethyl adipate from coking or decomposing at high temperature.
The liquid volume space-time rate of the esterification rectifying tower is 0.35h-1。
The purity of the adipic acid dimethyl ester product at the bottom of the esterification rectifying tower is 99.55 percent, the acid value of the adipic acid dimethyl ester is 0.5mgKOH/g, the adipic acid dimethyl ester product can be directly sold as a product, and the product can also be hydrogenated to produce a 1, 6-hexanediol product.
[ example 8 ]
This embodiment is described with reference to fig. 1 and the drawings.
Performing primary esterification reaction in a continuous stirring type reaction kettle at the reaction temperature of 100 ℃ and the reaction pressure of 0.08 MPaG; the number of the continuous stirring type reaction kettles is 2, the batch operation is carried out, the discharging is switched and connected to the esterification rectifying tower, and the continuous production and the full recovery of reaction heat can be realized.
The molar ratio of methanol to adipic acid in the reaction kettle is 5: 1; the reaction time was 5 hours.
The reaction kettle is filled with strong acid cation exchange resin, and the dosage of the resin is 4 percent (strong acid resin/adipic acid).
The stirring speed in the reaction kettle is 300 r/min.
The tower top pressure of the esterification rectifying tower is 0.08 MPaG; the tower bottom component is mainly dimethyl adipate, and the temperature of the tower bottom is 195 ℃ in order to prevent the dimethyl adipate from coking or decomposing at high temperature.
The liquid volume space-time rate of the esterification rectifying tower is 0.5h-1。
The purity of the adipic acid dimethyl ester product at the bottom of the esterification rectifying tower is 99.75 percent, the acid value of the adipic acid dimethyl ester is 0.3mgKOH/g, the adipic acid dimethyl ester product can be directly sold as a product, and the product can also be hydrogenated to produce a 1, 6-hexanediol product.
[ example 9 ]
This embodiment is described with reference to fig. 1 and the drawings.
Performing primary esterification reaction in a continuous stirring type reaction kettle at the reaction temperature of 100 ℃ and the reaction pressure of 0.08 MPaG; the number of the continuous stirring type reaction kettles is 2, the batch operation is carried out, the discharging is switched and connected to the esterification rectifying tower, and the continuous production and the full recovery of reaction heat can be realized.
The molar ratio of methanol to adipic acid in the reaction kettle is 5: 1; the reaction time was 5 hours.
The reaction kettle is filled with strong acid cation exchange resin, and the dosage of the resin is 4 percent (strong acid resin/adipic acid).
The stirring speed in the reaction kettle is 300 r/min.
The tower top pressure of the esterification rectifying tower is 0.08 MPaG; the tower bottom component is mainly dimethyl adipate, and the temperature of the tower bottom is 195 ℃ in order to prevent the dimethyl adipate from coking or decomposing at high temperature.
The liquid volume space-time rate of the esterification rectifying tower is 0.6h-1。
The purity of the adipic acid dimethyl ester product at the bottom of the esterification rectifying tower is 99.70 percent, the acid value of the adipic acid dimethyl ester is 0.5mgKOH/g, the adipic acid dimethyl ester product can be directly sold as a product, and the product can also be hydrogenated to produce a 1, 6-hexanediol product.
[ example 10 ]
This embodiment is described with reference to fig. 1 and the drawings.
Performing primary esterification reaction in a continuous stirring type reaction kettle at the reaction temperature of 100 ℃ and the reaction pressure of 0.08 MPaG; the number of the continuous stirring type reaction kettles is 2, the batch operation is carried out, the discharging is switched and connected to the esterification rectifying tower, and the continuous production and the full recovery of reaction heat can be realized.
The molar ratio of methanol to adipic acid in the reaction kettle is 5: 1; the reaction time was 5 hours.
The reaction kettle is filled with strong acid cation exchange resin, and the dosage of the resin is 4 percent (strong acid resin/adipic acid).
The stirring speed in the reaction kettle is 300 r/min.
The tower top pressure of the esterification rectifying tower is 0.08 MPaG; the tower bottom component is mainly dimethyl adipate, and the temperature of the tower bottom is 195 ℃ in order to prevent the dimethyl adipate from coking or decomposing at high temperature.
The liquid volume space-time rate of the esterification rectifying tower is 0.75h-1。
The purity of the adipic acid dimethyl ester product at the bottom of the esterification rectifying tower is 99.20%, the acid value of the adipic acid dimethyl ester is 0.5mgKOH/g, and the 1, 6-hexanediol product can be produced by hydrogenation.
[ COMPARATIVE EXAMPLE ]
Different from the embodiment 8, the energy-saving measures are not adopted, the gasified methanol is condensed and then returns to the reaction kettle, the jacket adopts circulating cooling water for heat removal, after the gas phase at the top of the esterification rectifying tower is condensed, one part of the gasified methanol is used as reflux, one part of the methanol-removing recovery tower is used as feeding material, and other conditions are the same.
The purity of the adipic acid dimethyl ester product at the bottom of the esterification rectifying tower is 99.75 percent, the acid value of the adipic acid dimethyl ester is 0.5mgKOH/g, the adipic acid dimethyl ester product can be directly sold as a product, and the product can also be hydrogenated to produce a 1, 6-hexanediol product.
Compared with example 4, 2 methanol condensers are added, the cooling load is increased by 32.7%, and the heating load is increased by 25.8%.
Claims (12)
1. An energy-saving method for producing dimethyl adipate comprises the following steps:
(1) adding methanol and molten adipic acid into a continuous stirring type reaction kettle to perform primary esterification reaction; the reaction temperature is 80-120 ℃, and the reaction pressure is 0.02-0.2 MPaG;
(2) feeding the reaction kettle liquid from the upper part of an esterification rectifying tower, feeding methanol from the lower part of the esterification rectifying tower, carrying out secondary esterification, directly feeding the gas phase at the top of the tower containing dimethyl ether into a methanol recovery tower, and controlling the temperature of the reaction section of the esterification rectifying tower to be 80-120 ℃;
(3) non-condensable gas containing dimethyl ether and a liquid phase containing light components are extracted from the top of the methanol recovery tower, methanol is extracted from a side-stream liquid phase, the methanol from which water and light component impurities are removed is divided into two parts, one part of methanol and fresh methanol are mixed and then used as reflux liquid of the esterification reaction rectifying tower, so that the reflux quantity of the esterification reaction rectifying tower is reduced, one part of methanol is circulated to a first stage of esterification and used as reaction liquid, and heavy components containing water are extracted from a tower kettle;
(4) methanol in the continuous stirring type reaction kettle is gasified and removed with heat, a jacket adopts methanol as a heat removal medium, methanol steam is used as the feeding material of an esterification reaction rectifying tower, the gas phase at the top of the esterification reaction rectifying tower is directly used as the feeding material of a methanol recovery tower without condensation, and ester products are directly used as products or sent into a hydrogenation unit to produce 1, 6-hexanediol without purification;
the number of the continuous stirring type reaction kettles is 2, the batch operation is carried out, and the discharging is switched and connected to the esterification rectifying tower.
2. The energy-saving method for producing dimethyl adipate as claimed in claim 1, wherein the molar ratio of methanol to adipic acid in the reaction kettle is 2-8: 1, and the reaction time is 3-8 hours.
3. The energy-saving method for producing adipic acid dimethyl ester according to claim 1, wherein a strong acid cation exchange resin is filled in the reaction kettle, and the using amount ratio of the strong acid cation exchange resin to adipic acid is 1-8%.
4. The energy-saving method for producing dimethyl adipate as claimed in claim 1, wherein the stirring speed in the reaction kettle is 100-400 r/min.
5. The energy-saving method for producing dimethyl adipate as claimed in claim 1, wherein the esterification rectifying tower and the methanol recovery tower both adopt high-efficiency low-resistance packing at the upper part and adopt plate-type towers at the lower part.
6. The energy-saving method for producing the dimethyl adipate as claimed in claim 1, wherein the catalyst in the reaction section of the esterification rectifying tower is suspended in a liquid layer on a plate, and any layer of the catalyst can be taken out and replaced without influencing the operation of the esterification rectifying tower.
7. The energy-saving method for producing dimethyl adipate as claimed in claim 1, wherein catalyst particles are packaged in a metal packing cage at the upper rectifying section of the esterification rectifying tower.
8. The energy-saving method for producing dimethyl adipate as claimed in claim 1, wherein the top pressure of the rectifying tower of the esterification reaction is 0.02-0.6 MPaG; the temperature of the tower kettle is 120-210 ℃.
9. The energy-saving method for producing dimethyl adipate as claimed in claim 1, wherein the top pressure of the rectifying tower of the esterification reaction is 0.04-0.2 MPaG; the temperature of the tower kettle is 165-195 ℃.
10. The energy-saving method for producing dimethyl adipate as claimed in claim 1, wherein the liquid volume space-time rate of the esterification rectifying tower is 0.2-0.6 h-1。
11. The energy-saving method for producing dimethyl adipate as claimed in claim 1, wherein the purity of the dimethyl adipate at the bottom of the esterification rectifying tower is more than or equal to 99.5%, and the acid value of the dimethyl adipate is less than or equal to 0.5 mgKOH/g.
12. The energy-saving method for producing dimethyl adipate as claimed in claim 1, wherein the method is suitable for producing diethyl adipate, diisooctyl adipate, dibutyl adipate and dimethyl succinate.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201711058562.1A CN109748791B (en) | 2017-11-01 | 2017-11-01 | Energy-saving method for producing dimethyl adipate |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201711058562.1A CN109748791B (en) | 2017-11-01 | 2017-11-01 | Energy-saving method for producing dimethyl adipate |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN109748791A CN109748791A (en) | 2019-05-14 |
| CN109748791B true CN109748791B (en) | 2021-08-03 |
Family
ID=66398907
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201711058562.1A Active CN109748791B (en) | 2017-11-01 | 2017-11-01 | Energy-saving method for producing dimethyl adipate |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN109748791B (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114160055A (en) * | 2021-10-27 | 2022-03-11 | 岳阳职业技术学院 | Membrane dryer, intermittent esterification reaction system and dimethyl adipate preparation method |
| CN115057771A (en) * | 2022-05-09 | 2022-09-16 | 湖北三宁碳磷基新材料产业技术研究院有限公司 | Method for preparing hexatomic carboxylic ester and novel production process method for preparing adipic diester product |
| CN116272815A (en) * | 2023-05-17 | 2023-06-23 | 江苏省瑞丰高分子材料有限公司 | Quick switching device of reaction kettle and rectifying tower |
Family Cites Families (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN100537511C (en) * | 2006-08-30 | 2009-09-09 | 中国石油天然气股份有限公司 | Method and equipment for continuous esterification production of adipic acid dimethyl ester |
| EP1955994B1 (en) * | 2007-02-08 | 2010-05-05 | Ems-Chemie Ag | Method for manufacturing DMA |
| CN102311342B (en) * | 2010-07-07 | 2014-01-01 | 中国石油化工股份有限公司 | Method for producing 1,6-dimethyl adipate |
| CN102442905B (en) * | 2010-10-12 | 2016-03-30 | 中国石油化工股份有限公司 | The method of preparing dimethyl adipate by continuous esterification |
| CN102351648B (en) * | 2011-09-09 | 2013-11-20 | 上海戊正工程技术有限公司 | Process for producing 1,6-hexanediol and coproducing epsilon-caprolactone |
-
2017
- 2017-11-01 CN CN201711058562.1A patent/CN109748791B/en active Active
Also Published As
| Publication number | Publication date |
|---|---|
| CN109748791A (en) | 2019-05-14 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN107739301B (en) | Polymethoxy dimethyl ether synthesis system and process | |
| CN109748791B (en) | Energy-saving method for producing dimethyl adipate | |
| CN102936198B (en) | Produce the method for vinyl acetate | |
| CN1830934A (en) | Method for producing dimethyl ether using methanol as raw material | |
| CN103044257A (en) | Alcoholysis method and device system for producing dioctyl terephthalate by polyester wastes | |
| CN109748790B (en) | Method for producing dimethyl adipate | |
| CN105111079A (en) | Method and device for separating acetic acid sec-butyl ester and sec-butyl alcohol | |
| CN103342642B (en) | Process for continuously producing dimethyl adipate through reaction-rectification method | |
| CN102795961B (en) | Device and method for synthesizing sec-butyl alcohol by continuous reaction-rectification | |
| CN101058534B (en) | Device and method for preparing dimethyl ether from methanol | |
| CN115160106A (en) | Production device and method of sec-butyl alcohol | |
| CN107011163A (en) | The method that acetylene method gas phase produces vinylacetate | |
| CN114984866B (en) | System and method for preparing dimethyl maleate | |
| CN110483282A (en) | A kind of device and method producing high concentration glycol acetate | |
| CN203007176U (en) | Alcoholysis device system for preparing dioctyl terephthalate from Dacron wastes | |
| CN102442893B (en) | Separation method of aldehyde condensation products | |
| CN109646977B (en) | Reactive distillation coupling tower and application thereof in preparation of formic acid | |
| CN102001938B (en) | Process and production system for synthesizing dimethyl oxalate or diethyl oxalate and coproducing oxalic acid | |
| CN109824498B (en) | Diacetone alcohol continuous production device and production process | |
| CN112409181A (en) | Dimethyl oxalate rectifying device for coal chemical industry | |
| CN106478402A (en) | The method that ethanol acid crystal is prepared by methyl glycollate | |
| CN218485928U (en) | Device for preparing carbonic ester by decarbonylation of oxalate | |
| CN217367194U (en) | Energy-conserving BDO rectifier unit | |
| CN109289721B (en) | Device and method for quickly taking away reaction heat in preparation of propylene oxide by HPPO method | |
| CN215085153U (en) | Special filtering equipment for oxidation system of maleic anhydride device |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |