CN109534999A

CN109534999A - A kind of synthesis technology and device of dimethyl carbonate

Info

Publication number: CN109534999A
Application number: CN201811454905.0A
Authority: CN
Inventors: 郑华艳; 李忠; 周龙; 张国强
Original assignee: Taiyuan University of Technology
Current assignee: Lu'an Chemical Group Co.,Ltd.; Taiyuan University of Technology
Priority date: 2018-11-30
Filing date: 2018-11-30
Publication date: 2019-03-29
Anticipated expiration: 2038-11-30
Also published as: CN109534999B

Abstract

A kind of synthesis technology of dimethyl carbonate uses cascade towers successive reaction, material liquid methanol is fed above the gas-liquid distributor of I reactor, enter the conversion zone of reactor after gas-liquid distributor outflow, unstrpped gas CO is passed through I reactor, O from the conversion zone bottom of reactor₂It is being divided into the road 2-5, cloth is between the conversion zone of reactor, dimethyl carbonate is generated under anticatalyst effect, form the water segregation section that mixed liquor A flows into I reactor, methanol and dimethyl carbonate continue to flow downwardly into tower reactor formation mixed liquid B by bottom hydrophobic membrane in mixed liquor A, and water collects discharge after penetrating surrounding hydrophilic film, and mixed liquid B enters II reactor in I reactor tower reactor, last crude product is produced from II reactor tower reactor, incoagulable gas CO, O after I, II reactor reaction₂And CO₂It is discharged Deng from reactor head.The present invention has the advantages that simple process, high methanol conversion ratio and low energy consumption.

Description

A kind of synthesis technology and device of dimethyl carbonate

Technical field

The invention belongs to a kind of synthesis technology of dimethyl carbonate and devices

Background technique

Dimethyl carbonate (DMC) is environmental-friendly chemicals.Under room temperature be colourless transparent liquid, can with alcohol, ketone, ester and The major part organic solvent such as ether dissolves each other, and is insoluble in water, there is high oxygen content, steam to force down, the characteristics such as volatile and hypotoxicity.Carbon Containing groups such as carbonyl and methyl in dimethyl phthalate molecule, phosgene can be replaced as carbonylation agent, instead of halide, sulfuric acid Dimethyl ester substitutes freon, chloroform etc. and is used as solvent, be used as instead of methyl tertiary butyl ether(MTBE) (MTBE) as methylating reagent Oil dope has a extensive future.

Since Enichem company nineteen eighty-three successfully develop methanol liquid phase oxidation carbonyl process preparation DMC technique since, oxidation Carbonylation method, which synthesizes DMC, becomes research hotspot.Oxidative carbonylation Synthesis of dimethyl carbonate is divided into vapor phase method and liquid phase method.Vapor phase method It is by gas-phase methanol, CO and O₂Mixed gas by generating DMC after the fixed bed reactors of loading catalyst, the technique is without urging Agent separation problem, but methanol one way conversion ratio is lower than 10%, and DMC is selectively lower than 70%, such as Yang Bing et al. (CHEMCATCHEM, 2014；2671-2679) use Cu₂O/AC catalyst synthesizes DMC, methanol list in fixed bed reactors Journey conversion ratio is about 9.2%, DMC selectively about 61%, and reaction process efficiency is lower.

Liquid phase method is passed through methanol as reactant and solvent in reaction kettle, and CO and O are then passed to₂Synthesize DMC.Ren Jun Et al. (modern chemical industry, 2007:228-234) using solid liposome nanoparticle method prepare SiO₂-TiO₂Composite oxide supported copper catalysis Agent carries out oxidative carbonylation in high pressure interval reaction unit and synthesizes DMC, and each factor is pressure on the sequence that reaction result influences > temperature > charge ratio > revolving speed, methanol conversion is 6.8%, DMC selectivity >=70% after optimization.

Princes and dukes answer et al. (CN105080610A, 2015) using dry powder catalyst, in 90-130 DEG C of temperature, pressure 2.0- The reaction of methanol liquid-phase oxidative carbonylation, conversion per pass >=30%, DMC selection of methanol are carried out in the batch autoclave of 3.0Mpa Property >=99.9%.

Li Guangxing et al. (CN1204644A, 1999) uses multitube recirculation reactor, by improving reactant contact area To promote methanol conversion, but DMC content only has 19.2% in crude product.Liquid phase continuous oxidation carbonyl compound is in DMC technique Methanol conversion is selectively greater than 95% lower than 40%, DMC, the two-stage series connection coproduction developed such as Quanzhou Henghe Chemical Co., Ltd. Technique (CN104418749A, 2015), the discharging of product gas-liquid mixture enter next reactor, by the series connection of two reactors come Methanol conversion is improved to 30%.The technique has the disadvantage in that 1) gas-liquid mixed discharging energy consumption is big；2) water that reaction generates stops It stays in a kettle, causes DMC hydrolysis serious；3) DMC content is lower than 40% in crude product, later period extraction, azeotropic or change Press the energy consumption of rectified purified DMC technique very big.

Summary of the invention

The object of the present invention is to provide a kind of simple process, high methanol conversion ratio and the conjunctions of the methanol oxidative carbonylation that low energy consumption At the technique and device of dimethyl carbonate.

Synthesis of dimethyl carbonate of the invention, includes the following steps:

Using cascade towers successive reaction, material liquid methanol is fed above the gas-liquid distributor of I reactor, from gas Entering the conversion zone of reactor after liquid distributor outflow, unstrpped gas CO is passed through I reactor from the conversion zone bottom of reactor, O₂It is being divided into the road 2-5, is being passed through all the way from the conversion zone bottom of I reactor, other roads are distributed between the conversion zone of reactor, Successive reaction generates dimethyl carbonate under the action of reacting section catalyst.The carbonic acid two that the unreacted methanol in part, reaction generate Methyl esters and by-product water form the water segregation section that mixed liquor flows into I reactor, and methanol and dimethyl carbonate pass through in mixed liquor A Bottom hydrophobic membrane continues to flow downwardly into tower reactor formation mixed liquid B, and water collects discharge, I reactor column after penetrating surrounding hydrophilic film Mixed liquid B enters II reactor, mixed liquid B, unstrpped gas CO and O by pump in kettle₂Into II reactor mode with The mode that raw material enters I reactor is identical, and last crude product is produced from II reactor tower reactor, after I, II reactor reaction Incoagulable gas CO, O₂And CO₂It is discharged Deng from reactor head.

As described above catalysis reaction condition are as follows: in reaction system reaction pressure be 1-7Mpa, reaction temperature be 30 DEG C- 200 DEG C, raw material liq methanol air speed 0.1-4h^-1, the charging mole group of raw material is as CO:30-70mol%, O₂: 5- 10mol%, methanol: 20-65mol%.

The catalyst loaded in the conversion zone of I, II reactor as described above is with granular activated carbon (AC), carbon nanotube (CNT) and molecular sieve etc. be carrier copper-based (Cu) catalyst of load.Such as Cu/N-CNT catalyst in patent CN107686105A, The doping that the load capacity of Cu is 8.7%, N is 5.6%, remaining is carbon nanotube；Such as " advanced chemical journal " (2016,37 (7), 1380-1890) in Cu/AC catalyst, the load capacity of Cu is 8.4%, and active carbon accounts for 91.6%；Such as patent Cu/Y catalyst in CN107519913A, Cu load capacity are 10.5% (Cu^I95%), remaining is Y type molecular sieve etc..

The reactor water segregation section bottom I and II as described above is equipped with hydrophobic film, as super thin in patent CN101608109 Hydrophobicity Silicalite-1/zein composite load in aqueous film, or " membrane science and technology " (2013,33 (4), 43-45) Film.Hydrophilic film is housed, such as hydrophilic film in patent CN102131567A, or " modern chemical industry " (2011,31 around water segregation section (12), 23-27) in hydrophily NaA molecular sieve membrane etc..

The present invention designs a kind of reactor, using Liquid Phase Methanol, carbon monoxide and oxygen as reaction raw materials, is urged using a certain amount of Agent efficiently synthesizes dimethyl carbonate.

I with II reactor configuration is identical, and by taking I reactor as an example, and reactor can be divided into upper section, middle section, lower section With four part of tower reactor.Upper section is gas-liquid separation section, inside has feed liquor distributor, outlet distributor is arranged at upper section top, and there is gas on top Outlet；Middle section is conversion zone, and porcelain ball bed is arranged at middle section top, and middle part is divided into porcelain ball bed and catalyst bed, in catalyst bed On have oxygen air inlet and oxygen air inlet, bottom oxygen air inlet and carbon monoxide air inlet are arranged at lower part, and in middle section, outer wall has Heat preservation layer has Heat preservation stick inside middle section；Lower section is water segregation section, and water outlet, upper section, middle section, lower section are arranged at bottom It is linked together with tower reactor, diameter is identical, there is liquid outlet in tower reactor.

Feed liquor distributor as described above is located at upper section middle, outlet distributor preferred embodiment be positioned at feed liquor distributor and Between upper section top at 1/3-2/3, aperture is 0.5-3.0 millimeters on outlet distributor, and percent opening preferred scope is 10- 30%.

Porcelain ball bed as described above is provided with the porcelain ball that diameter is 1-3 millimeters, and catalytic bed is provided with catalyst, loads Amount and conversion zone internal diameter and high-positive correlation.

The bottom of lower section as described above is equipped with hydrophobic film, and thicknesses of layers is 15-30 microns, and surrounding is equipped with hydrophilic film, Thicknesses of layers is 20-40 microns, and water segregation section is equipped with water outlet, for separating the water generated in reaction process.

I, II three sections of height of reactor as described above compare for upper section: middle section: lower section=1:(3-10): (1-2), on Section, middle section and lower section ratio of height to diameter are between 5-15:1.

The conversion zone in middle section as described above is 1-4 sections.

The present invention is connected by two reactors after successive reaction, and dimethyl carbonate mass content is higher than 80% in crude product, The high purity carbon dimethyl phthalate product of 99.9wt% can be obtained by simple compression rectification.

The present invention has the advantages that compared with existing methanol liquid-phase oxidative carbonylation produces dimethyl carbonate technology

1. Liquid Phase Methanol and vapor-phase reactant are sufficiently reacted in catalyst bed counter current contacting, continuously anti-by cascade towers It answers, substantially increases the content of dimethyl carbonate in crude product, reduce energy consumption needed for product purification；

It is equipped with water segregation section in 2.I, II reactor, reduces the contact of by-product water and catalyst and dimethyl carbonate Time, the service life of catalyst is on the one hand improved, on the other hand inhibits the hydrolysis of dimethyl carbonate；

3. needing to separate liquid product with catalyst in Traditional liquid phase method, process flow is complicated.And the present invention is not There are the separation problems of product and catalyst, simplify process flow；

4. the technology of the present invention has process flow simple, catalyst life is long, methanol conversion and dimethyl carbonate yield Height, low power consumption and other advantages.

Detailed description of the invention

Fig. 1 is the flow chart of this technique.

Fig. 2 is structure of reactor figure of the present invention.

As shown in the figure: 1 is upper section, and 2 be middle section, and 3 be lower section, and 4 be tower reactor, and 5 be feed liquor distributor, and 6 be outlet distribution grid, 7 be porcelain ball bed, and 8 be catalyst bed, and 9 be heating rod inside conversion zone, and 10 be hydrophilic film, and 11 be hydrophobic film, and 12 are Gas vent, 13 be Heat preservation layer, and 14 and 15 are conversion zone oxygen air inlets, and 16 be conversion zone bottom oxygen air inlet, 17 It is carbon monoxide air inlet, 18 be water outlet, and 19 be liquid outlet, and 20 be crude product extraction mouth

Specific embodiment

Embodiment 1

1 height of upper section of I and II reactor of the present invention is 300 millimeters, and 2 height of middle section is 1200 millimeters, 3 height of lower section It is 400 millimeters, 4 height of tower reactor is 300 millimeters, and identical four section diameters are 80 millimeters.Feed liquor distributor 5 is located in upper section 1 Between position, outlet distributor 6 is located at 1/2 between 1 top of feed liquor distributor 5 and upper section, and percent opening is on outlet distributor 6 15%, aperture 1.5mm.The conversion zone in middle section 2 is divided into upper and lower two sections, and porcelain ball bed (7) is between two sections and on conversion zone Section top loads Cu/AC catalyst 1600g using accumulation mode in bulk in catalyst bed 8, and 800g catalysis is first added in when filling Conversion zone lower section is filled up in agent, and the porcelain ball tiling that rear addition 60ml diameter is 2mm forms porcelain ball bed (7) on a catalyst, then plus Enter 800g catalyst and fill up conversion zone top, the porcelain ball tiling that 60ml diameter is 2mm is added again and forms reaction on a catalyst The porcelain ball bed of section upper section.O₂It is divided into three tunnels, (16) are passed through from the conversion zone bottom of reactor all the way, and (15) are located at reaction all the way At 1/3 between section porcelain ball bed (7) and conversion zone bottom, (14) are located at the top of conversion zone porcelain ball bed (7) and conversion zone all the way Between at 1/2, CO (17) is passed through from the conversion zone bottom of reactor.3 bottom of lower section uses Silicalite-1/zein Compound Negative Hydrophobic film 11 is carried with a thickness of 20 microns, around using hydrophily NaA molecular sieve membrane 10 with a thickness of 30 microns.Start to react preceding original Batch can fills 10 liters of pure methanol, persistently supplements in subsequent experimental, and reactor passes through N₂Purging, CO and O₂Gas displacement etc. is ready Afterwards, enter I reactor after the heating of liquid phase feed preheated device, reacted with reaction gas counter current contacting, material liquid methanol with The flow velocity of 2ml/min enters feed liquor distributor 5, reaction gas CO flow 600ml/min, reaction gas O₂Divide three Lu Jinqi, three roads stream Amount is 40ml/min, and total flow 120ml/min, feedstock mole group is as methanol: 49.7%, CO:44.9%, O₂: 5.4%.Inside reactor oxygen content is controlled in explosion limit, it is ensured that experiment safety.Change again after reactor pressure decrease is stablized The reaction conditions such as reaction temperature, pressure, liquid phase feed flow velocity and reaction gas flow velocity, avoid liquid flooding.I and II reactor pressure is 3Mpa, the control of 1 temperature of upper section is in room temperature, and the regulation of 2 samming of middle section is at 120 DEG C, and precision is lower than 2 DEG C, and 3 temperature of lower section is lower than 50 DEG C, Precision is lower than 3 DEG C, and the control of feeding preheating temperature is at 120 DEG C, and precision is lower than 1 DEG C, and temperature of each section can be adjusted as the case may be Control.

In this technique, after I reactor reaction, calculating methanol conversion per pass is 54%, through II reactor reaction Afterwards, DMC content reaches 90.5% in the crude product of bottom, incoagulable gas such as CO, O₂And CO₂It is discharged after processing.Under the technique, After I, II reactor reaction, DMC content is up to 90.5% in product, and methanol conversion is up to 85.1%.

2 length of modulation reactor middle section, tower internal diameter, catalyst type and dosage in embodiment 2-8, reaction condition etc. because Element.Specific catalyst parameters are as shown in Table 1, and reaction unit and loadings are as shown in Table 2, and reaction condition and II reactor are adopted Crude product interpretation of result is as shown in Table 3 out.

Table one:

Table two:

Table three:

The above description is only an embodiment of the present invention, is not intended to limit the scope of the invention, all to utilize this hair The equivalent exchange that bright description is done, is applied directly or indirectly in relevant technical field, is similarly included in this hair In bright scope of patent protection.

Claims

1. a kind of synthesis technology of dimethyl carbonate, it is characterised in that include the following steps:

Using cascade towers successive reaction, material liquid methanol is fed above the gas-liquid distributor of I reactor, from gas-liquid point Enter the conversion zone of reactor after the outflow of cloth device, unstrpped gas CO is passed through I reactor, O from the conversion zone bottom of reactor₂? It is divided into the road 2-5, is passed through all the way from the conversion zone bottom of I reactor, other roads is distributed between the conversion zone of reactor, are being reacted Successive reaction generates dimethyl carbonate, the dimethyl carbonate that the unreacted methanol in part, reaction generate under the action of section catalyst The water segregation section that mixed liquor A flows into I reactor is formed with by-product water, methanol and dimethyl carbonate pass through bottom in mixed liquor A Portion's hydrophobic membrane continues to flow downwardly into tower reactor formation mixed liquid B, and water collects discharge, I reactor tower reactor after penetrating surrounding hydrophilic film Middle mixed liquid B enters II reactor, mixed liquid B, unstrpped gas CO and O by pump₂Into the mode and original of II reactor The mode that material enters I reactor is identical, and last crude product is produced from II reactor tower reactor, after I, II reactor reaction not Solidifying property gas CO, O₂And CO₂It is discharged Deng from reactor head.

2. a kind of synthesis technology of dimethyl carbonate as described in claim 1, it is characterised in that described in reacting section catalyst Under the action of successive reaction generate the condition of dimethyl carbonate are as follows: reaction pressure is 1-7Mpa in reaction system, and reaction temperature is 30 DEG C -200 DEG C, raw material liq methanol air speed 0.1-4h^-1, the charging mole group of raw material is as CO:50-70mol%, O₂:5- 10mol%, methanol: 20-40mol%.

3. a kind of synthesis technology of dimethyl carbonate as described in claim 1, it is characterised in that I, II reactor The catalyst loaded in conversion zone is Cu/N-CNT catalyst, and the doping that the load capacity of Cu is 8.7%, N is 5.6%, remaining is Carbon nanotube or Cu/AC catalyst, the load capacity of Cu are 8.4%, and active carbon accounts for 91.6% or Cu/Y catalyst, and Cu load capacity is 10.5%, wherein Cu^ІIt is 95%, remaining is Y type molecular sieve.

4. a kind of synthesis technology of dimethyl carbonate as described in claim 1, it is characterised in that I the and II reactor Hydrophobic film is superhydrophobic films or hydrophobicity Silicalite-1/zein Compound Negative film carrier.

5. a kind of synthesis technology of dimethyl carbonate as described in claim 1, it is characterised in that the parent of the I and II reactor Aqueous film is hydrophilic film or hydrophily NaA molecular sieve membrane.

6. a kind of synthesis technology of dimethyl carbonate, it is characterised in that I with the II reactor configuration is identical.

7. a kind of reactor, it is characterised in that reactor is divided into upper section (1), middle section (2), lower section (3) and tower reactor (4) four Point, upper section (1) is gas-liquid separation section, is inside had feed liquor distributor (5), outlet distributor (6) are arranged at upper section (1) top, and there is gas on top Body exports (12)；Middle section (2) is conversion zone, and porcelain ball bed (7) is arranged at middle section (2) top, and middle part is divided into porcelain ball bed (7) and catalyst Bed (8), there is oxygen air inlet (14) and oxygen air inlet (15) on catalyst bed (8), and bottom oxygen air inlet is arranged at lower part Mouth (16) and carbon monoxide air inlet (17), in middle section, outer wall has Heat preservation layer (13), has Heat preservation inside middle section (2) Stick (9)；Lower section (3) is water segregation section, and bottom has water outlet (18), and upper section (1), middle section (2), lower section (3) and tower reactor (4) are linked as One, diameter is identical, there is liquid outlet (19) in tower reactor (4).

8. such as a kind of reactor of claim 7, it is characterised in that the feed liquor distributor (5) is located at upper section (1) middle, outlet Distributor (6) is between feed liquor distributor (5) and upper section (1) top at 1/3-2/3.

9. such as a kind of reactor of claim 7, it is characterised in that aperture is 0.5-3.0 millimeters on outlet distributor (6), percent opening For 10-30%.

10. such as a kind of reactor of claim 7, it is characterised in that the porcelain ball bed (7) is provided with the porcelain that diameter is 1-3 millimeters Ball.

11. such as a kind of reactor of claim 7, it is characterised in that the bottom of the lower section (3) is equipped with hydrophobic film (11), film layer With a thickness of 15-30 microns, surrounding is equipped with hydrophilic film (10), and thicknesses of layers is 20-40 microns, and water segregation section is equipped with water outlet (18)。

12. such as a kind of reactor of claim 7, it is characterised in that three sections of height of the reactor compare for upper section: middle section: lower section= 1:(3-10): (1-2), upper section, middle section and lower section ratio of height to diameter are between 5-15:1.

13. such as a kind of reactor of claim 7, it is characterised in that the conversion zone of the middle section (2) is 1-4 sections.