CN102908956B - Esterification reactor and production method of dimethyl maleate - Google Patents
Esterification reactor and production method of dimethyl maleate Download PDFInfo
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- CN102908956B CN102908956B CN201110217525.7A CN201110217525A CN102908956B CN 102908956 B CN102908956 B CN 102908956B CN 201110217525 A CN201110217525 A CN 201110217525A CN 102908956 B CN102908956 B CN 102908956B
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Abstract
The invention relates to an esterification reactor and a production method of dimethyl maleate. The esterification reactor is suitable for esterification reactions of carboxylic acids and alcohols. The reactor is composed of a plurality of tower plates; each tower plate is provided with a downtake pipe and an ascension pipe, wherein the ascension pipe is connected with a gill type gas distributor; each tower plate reserves a certain liquid level liquid, wherein the liquid contains a solid catalyst; and the liquid phase is a component containing a carboxylic acid, flows downward from an esterification tower plate to the following tower plate in the reactor, and reacts with rising alcohol steam countercurrent. The esterification reactor has the advantages of adequate contact of three phases (gas, liquid and solid), high reaction efficiency, high volume utilization rate of the reactor, and the like; and is suitable for various esterification reaction processes.
Description
Technical field
The present invention relates to the production method of a kind of reactor and dimethyl maleate, be particularly applicable to the reactor that carboxylic acids and alcohols material carry out esterification.
Background technology
Esterification reacts by monoacid, binary acid or polyacid (also can be acid anhydrides under specified conditions) and alcohol or aldehydes matter the process generating ester, and esterification is generally reversible balanced reaction.These alcohol, aldehydes matter can be monohydric alcohol, dihydroxylic alcohols or polyalcohol.As follows for monoesters course of reaction:
R
1can be the organic group of a hydrogen atom or unit price, R
2it is the organic group of unit price.When reactant is acid anhydrides, reaction is divided into two steps:
R
3divalent organic group, R
4it is monovalent organic groups.
Reaction equation 2 can automatically can react under the condition of catalyst-free, and the organic acid of generation can catalytic reaction 1 and reaction 3 to a certain extent.But usually need in reactant, to add catalyst to promote the carrying out of esterification.
The most frequently used catalyst is sulfuric acid and the sulfur-bearing organic acid as benzene sulfonic acid etc.But these catalyst are homogeneous catalyst, although catalytic effect is very good, just can obtain ester phase product after having to pass through neutralization reaction, neutralization procedure commonly uses strong base reagent (as sodium hydroxide solution), and this process has following shortcoming:
1, esterification is the reaction that balances each other, and unreacted carboxylic acid can participate in neutralization reaction, and from carboxylic acid salt solution, be separated unreacted carboxylic acid very difficult, so neutralization procedure can cause obvious significant loss in this technique;
2, have the ester of part to be dissolved in alkali lye in neutralization reaction process, have part ester to be dissolved in alkali lye with sodium-salt form, the loss amount of ester depends on the solubility of ester in alkali lye;
3, the organic carboxylate produced in water-washing process can aggravate problem of environmental pollution;
4, when containing LCFA in product, can react with strong base solution and form highly basic soap, hard soap is surfactant, meets water and forms stable emulsion, be difficult to carry out water-oil separating.Adopt homogeneous catalyst to carry out continuous esterification and have a lot of shortcoming, usually adopt intermittent reaction, product quality is not high.
5, adopt another shortcoming of homogeneous catalyst be ester mutually in be mixed with sulfur component, and sulfur component will have a strong impact on subsequent process and operate.
For addressing this problem, development in laboratory is a kind of take acid-exchange resin as the technique of Catalyst Production dimethyl maleate.At EP-A-0255399, this technology is set forth.Describe according to patent, liquid phase is monomethyl maleate, react with alcohol steam continuous flow upstream in the region that esterification catalyst is housed and prepare dimethyl maleate, in tower, solid catalyst is deposited in the guard on column plate in trickle bed mode, and the liquid phase esterification zone counter current contacting that the alcohol steam more and more higher with concentration is being equipped with catalyst that flows downward is reacted.Another kind of reactor types is one group of continuous stirred tank be connected.Liquid phase flows to next reactor by a reactor, and alcohol steam flows to previous reactor by next reactor simultaneously.This mode of operation complicated operation, and reaction efficiency is lower.
Technical scheme described in EP-A-0255399 and WO-A-88/00937 is comparatively complicated.Have the column plate of multiple band guard in reaction tower, ion-exchange resin catalyst is contained in guard.This compound reactor system needs to carry out continued operation to mixer, is difficult to implement.WO-A-90/08127 discloses a kind of esterifier and technique, uses plate column plate-type reactor, but needs in reactor every layer column plate reaction compartment, to arrange vertical plate washer, to increase the contact effect of reaction mass.This mode limited use, can not make bed temperature and hydrodynamics evenly, be difficult to the service efficiency effectively improving reactor.
Summary of the invention
For the deficiencies in the prior art, the invention provides the production method of a kind of esterifier and dimethyl maleate, esterifier of the present invention is by arranging the vapor distributor of suitable configurations, the acidic catalyst of solid particle is easily loaded and is easy to suspend, reactor utilization rate is high, and reaction efficiency is high.The present invention also provides a kind of production method of dimethyl maleate, and use ion-exchange resin catalyst, under reactiveness, catalyst is suspended in reaction mass.
Esterifier of the present invention, comprise tower-like reactor shell, at least one deck column plate is installed in housing, solid esterification catalyst bulk storage is on column plate, downspout through column plate and riser are set, liquid level on downspout upper end open and column plate is suitable, downspout lower openings stretches into below adjacent lower column plate liquid level, riser is communicated with gas distributor in the position on column plate top, gas distributor is fish gill formula gas distributor, gas distributor is made up of air entraining pipe and the fish gill formula distribution of gas mouth be distributed on air entraining pipe, air entraining pipe is connected on riser, air entraining pipe the latter half cylinder is arranged the notch of inclination, cover film sleeve pipe outside notch, the edge on the corresponding long limit of air entraining pipe notch of membrane casing has scarfing.
In esterifier of the present invention, air entraining pipe can comprise main air entraining pipe and an air entraining pipe, and main air entraining pipe is generally Straight, and main air entraining pipe is communicated with riser, and an air entraining pipe can be spirally coiled, also can be Straight, and an air entraining pipe is communicated with on main air entraining pipe.The quantity of main air entraining pipe and an air entraining pipe can be determined according to the scale of reactor.
In esterifier of the present invention, the distance of air entraining pipe and column plate is generally 100mm ~ 500mm, preferred 100mm ~ 200mm.Inclined notch on air entraining pipe is generally bar shaped, and the width of notch is generally greater than 1.5mm, and be preferably 2 ~ 20mm, the length of notch is generally 5% ~ 30% of air entraining pipe girth.The angle of inclination (notch and horizontal angle) of notch is generally 15 ~ 75 degree, is preferably 30 ~ 50 degree.Notch is uniformly distributed on air entraining pipe, or makes diverse location gas be the distribution mode that design discharge is determined to be suitable for by fluid mechanical design.
In esterifier of the present invention, the scarfing of the membrane casing covered outside air entraining pipe notch is arranged on the edge on the long limit of air entraining pipe notch, scarfing can be arranged on the edge on any one long limit in two long limits of air entraining pipe notch, scarfing position can service notch adjustment ejection air-flow direction, namely have guide effect to air-flow when scarfing is opened under airflow function, the direction of guide effect is the air entraining pipe notch edges side arranging scarfing.Air current flow direction is as required arranged.The position of scarfing is generally air entraining pipe notch long limit side edge epi 1mm ~ 7mm, preferred extension 2mm ~ 5mm, and concrete scarfing position is determined according to hydrodynamics distribution, thin-film material intensity and thin-film material elasticity.The length of scarfing is generally 70% ~ 150% of air entraining pipe notch length, is preferably 80% ~ 120%.Can being made up of corrosion resistant alloy foil sheet of the membrane casing covered outside air entraining pipe notch; Can also make for non-metal anti-corrosion material; Can also be that the composite film material of alloy and non-metal anti-corrosion material is made.Non-metal anti-corrosion material as: anti-corrosive rubber, polytetrafluoroethylene, natural or synthesis resin, polyester film etc. have the material of good corrosion resistance and elastic strength.
This scarfing is only and is cut open by membrane casing in desired location, does not need to slice off any position, and the state class that this scarfing is opened in operation is like the fish gill, and the gas distributor therefore in the present invention is called fish gill formula gas distributor.
In reactor of the present invention, in order to ensure distribution of gas and the effective deposition washing away bottom tower tray being avoided to catalyst of formation, gas is generally greater than 10m/s by the gas speed of scarfing, but in order to limit the resistance drop that gas distributor causes, the present invention limits this gas flow rate and is less than 100m/s, generally gets 20m/s-50m/s.When tower pressure drop hour, scarfing diminishes, and produces fine and closely woven bubble; When tower pressure drop is large, scarfing becomes large, and gas speed improves, and produces fine and closely woven bubble equally.Scarfing due to gas distributor has certain inclination angle, and gas sprays downwards at a slant, and its shear stress plays a role in promoting to W-response liquid, avoids the existence of reactor blind area.Be conducive to distribution of gas so even, and produce enough little bubble, improve the uniformity of reaction system, improve reaction efficiency, improve reactor volume utilization rate.
When esterifier of the present invention uses, column plate quantity can require specifically to determine according to product quality after the character of reaction mass and reaction, is generally 3 ~ 50 pieces.Each column plate retains certain liquid, filling solid esterification catalyst at least part of column plate.
The production method of dimethyl maleate of the present invention, use the above-mentioned esterifier of the present invention, with monomethyl maleate and methyl alcohol for raw material, take storng-acid cation exchange resin as catalyst, monomethyl maleate is introduced from reactor head with liquid form, methyl alcohol is introduced from reactor bottom with gas phase, arranges 10 ~ 40 pieces of sieve plates in reactor, obtains dimethyl maleate and draw reactor from reactor bottom after reaction.
The concrete reaction condition that dimethyl maleate is produced is: the mol ratio 1:1.5 ~ 1:5 of maleic acid mono alkyl ester/alkylol, the cumulative volume air speed of liquid phase feeding to resin catalyst of maleic acid mono alkyl ester is 0.2h
-1~ 2.0h
-1, reaction temperature is 90 DEG C ~ 160 DEG C, and reactor bottom inlet steam pressure limit is 0.1MPa to 3MPa.
Esterifier of the present invention uses solia particle or beaded catalyst, avoids the great number of issues using homogeneous catalyst to bring.Reactor of the present invention uses the gas distributor of suitable configurations simultaneously, improves reaction efficiency, improves reactor and holds title utilization rate, improve the disposal ability of whole reaction system.
Accompanying drawing explanation
Fig. 1 is a kind of tower plate structure schematic diagram comprising downspout and riser of esterifier of the present invention.
Fig. 2 is esterifier gas distributor structural representation of the present invention.
Fig. 3 is esterifier gas distributor air entraining pipe cross section of the present invention knot schematic diagram.
Detailed description of the invention
In use, two kinds of chargings are a kind of with liquid form introducing, and another kind of with gas phase introducing, while reaction, the water-band of reaction generation goes out by gas-phase feed, improves the purity of reaction conversion ratio and final products for esterifier of the present invention.Require under first block of column plate (top column plate) place's pressure, the boiling point of esterifier outlet mixed vapour, or in outlet mixed vapour, the boiling point of most light component to be starkly lower than any one component boiling point under this condition in heavy constituent product.In general, under same pressure, boiling point difference at least 15 DEG C, is preferably more than 25 DEG C, to realize realizing distillation while reaction.
In this area, be suitable for adopting the reaction of reactor of the present invention to mainly include machine acid or organic acid anhydride and alcohol and react the course of reaction of producing corresponding esters.For the production process of organic acid dibasic acid esters, generally with the monoesters after single-esterification and corresponding alcohol for charging, adopt reactor of the present invention to carry out the catalytic distillation reaction of double esterification.
In the present invention, single-esterification refers to generate unary fatty acid ester by unary fatty acid and alkanol or acid anhydrides and reaction of alkanol, and unary fatty acid here refers to the aliphatic acid comprising 6 ~ 26 carbon, or two or more mixture wherein.Preferably the alkanol of 1 ~ 10 carbon number obtains Arrcostab.
Reactor of the present invention may be used for the production of monobasic acid ester.Monoacid comprises aliphatic acid as similar aliphatic acid and two kinds or two or more mixtures such as capric acid, dodecylic acid, tetradecanoic acid, linoleic acid, myristic acid, palmitic acid, stearic acid, oleic acid, linoleic acid, arachic acid, isostearic acids.Aliphatic acid can react fatty acid methyl ester admixture processed with methyl alcohol, and fatty acid methyl ester repeated hydrogenation alkanol, as C
8to C
20alkanol (being usually also washing agent alcohols), separation making detergent can be carried out to alkanol.
Reactor of the present invention is also applicable to the production of di-fatty acid esters.React obtained by alkanol and dicarboxylic acids or its acid anhydrides or dicarboxylic acids and acid anhydride mixture thereof.Produce dicarboxylic esters as oxalate diester, maleic acid diester, succinic diester, fumaric acid diester, penta diester, heptan diester, azelaoyl, also comprise oxolane, comprise all from C
1to C
10alkyl acid ester.Any raw material that can be used as this dicarboxylic esters of production containing dicarboxylic acids or its acid anhydrides (if existence) or dicarboxylic acids and composition thereof.
C
7to C
20the preparation of unitary alkyl aromatic ester and composition thereof be also applicable to the present invention, as benzoic acid and the acid of 1-naphthols etc.The present invention is equally applicable to C
8to C
20aromatic acid, acid anhydride and composition thereof preparation binary aromatic carboxylic acid esters.The present invention is equally applicable to polyacid and prepares polynary ester.Polyacid has: citric acid, pyromellitic acid dianhydride etc.The present invention is equally applicable to prepare binary alcohol esters and polyol ester, and dihydroxylic alcohols is as ethylene glycol, propane diols etc., and polyalcohol is as glycerine, sorbierite, sweet mellow wine, xylitol etc.
Esterification Conditions Temperature in reactor be normal temperature to 200 DEG C, if temperature range is at 80 DEG C to 180 DEG C, preferably 100 DEG C to 135 DEG C.Requiring the Thermodynamically stable of esterification catalyst, and the steam group of esterifier bottom steam entrance divides relevant temperature and the kinetics of pressure, selects this operating temperature under condition.Reactor bottom inlet steam pressure limit is 0.1MPa to 3MPa, is preferably between 0.2MPa to 2.5MPar.Reactor space velocity range is 0.1h
-1to 10h
-1, especially 0.2 h
-1to 5h
-1.
Alcohol, acid or the liquid phase of its mixture composition the ester product of circulation solvent or diluent are by the top charging of reactor.Can also, to entering the alcohol before reactor and acid first be carried out without the pre-esterification reactor under catalytic condition, also can be the pre-esterification reactor had under catalytic condition under given conditions.Such as acid anhydrides such as maleic anhydride and phthalic anhydride and fatty alcohol such as methyl alcohol, ethanol, the tert-butyl alcohol react, obtain under the condition relatively relaxed monoesters as: 60 DEG C, 0.5MPa without the condition of catalysis under reaction equation as follows:
R
5that alkyl is as methyl, ethyl, butyl.This monoesters is also monoacid.Further reaction is as follows:
The result mixture that to be product be containing monoesters, dibasic acid esters, water and alkanol.If need to add excessive alkanol again, monoesters is made to react generating portion diester further in the reactor.
Tower top discharging is in the present invention mixed vapour.The mixed vapour that light component (normally alkoxide component) forms in the reactor carries out stripping to carboxylate product and other composition (normally carboxylic acid composition) and gets back to reactor to make it.Overhead vapours is separated its component with condensing mode, the water that esterification generates and light component (normally alcohol), and the dry Posterior circle of light component uses.Water vapour on the esterification column plate of the bottom is fewer, and esterification conversion ratio is more close to 100%, and the carboxylic acid content in the product of reactor bottom at the bottom of tower is lower.But the impact of the alcohol steam that esterification equilibrium is often supplied (i.e. light component steam), as the alkyl alcohol. vapor of the drying of abundance will be provided in reactor, when the alcohol steam of drying reduces, just need the operation changing liquid phase feeding, make it reach product requirement with the quality improving ester product.This will cause the reaction between alcohol, and influencing each other and the effect of alcohol-water separation between alcohol and water is depended in reaction.Water when using methanol steam in reactor in alcohol steam will be less than 5mol%, most preferably less than 1mol%.
Containing many column plates in reactor.Although sometimes only have two or three piece of column plate reaction, in usual reactor, there are 5 to 20 or more esterification column plate.The time of staying that every block esterification column plate designs is 1 minute to 120 minutes, particularly 5 to 60 minutes.Can design according to Con trolling index.
Solid catalyst is for containing-SO
3the granular ion exchange resin of H/-COOH.Proper resin has " DZH large porous strong acid resin ", " NKC-9 ", " D001 ", " ZG C 132 ", " CT450 " etc., specifically can select according to the type of esterification, specifically can select various suitable commercial product.
Column plates different in reactor is equipped with different catalyst, and the filling concentration on even not same column plate is also different.The loadings corresponding requirements catalyst weight of the particulate on every block column plate or beaded catalyst accounts for liquid weight ratio and is at least 0.2%; such as resin concentration scope is calculated as 2% ~ 20% with dried resin; preferably 5% ~ 10%, under the suitable time of staying and relevant operating condition, load enough catalyst to reach molecular balance or close to molecular balance.On the other hand can not sc catalyst to such an extent as to make the ascending air bottom column plate be difficult to be stirred into suspension.
Catalyst particle diameter should be enough large to make it easily be retained by the cover on column plate or similar devices.But the larger suspension and catalyst surface area is reduced of being more hard to keep of the particle of catalyst, so catalyst granules again can not be too large, proper catalyst particle diameter scope is 0.1mm to 5mm, is preferably 0.4mm to 0.8mm.
Esterification column plate provide one or more washing column plate to retain product in reactor and solvent and/or reagent.
Note avoiding local to have solid esterification catalyst to precipitate, because side reaction may be caused like this to occur, or there is focus in local as far as possible.Can guarantee, by the stirring action of ascending air to liquid, catalyst granules can be made to remain on suspended state by the distributor of column plate reasonable in design.In order to reach this object, at least part of esterification column plate or more (preferably whole column plate) will be set as inclined-plane to the turbulent region manufactured by distributor.Inclination angle prioritizing selection is more than or equal to the dwell angle in the liquid phase of solid catalyst on column plate.The object of this angle is adopted to be that the catalyst all when operating and liquid all move up and do not have blind area, because blind area can cause some side reactions.
The device preventing liquid suck-back preferably installed by the esterification column plate (one or more are preferably whole) passed through there being ascending air, prevents the device of liquid suck-back to be generally arranged in riser, general employing backward stop valve arrangement.Dependency structure installs protective cover, and protective cover is generally arranged on the upper opening of downspout, and the mesh diameter of protective cover is generally less than the particle diameter using catalyst, effectively to prevent esterification catalyst spilling to lower channel from esterification column plate.Solid catalyst is prevented to run off from one block of column plate to next block column plate fully by such method.
Esterifier of the present invention uses solia particle or beaded catalyst, avoids the great number of issues using homogeneous catalyst to bring.Reactor of the present invention uses coiled gas distributor simultaneously, improves reaction efficiency, improves reactor and holds title utilization rate, improve the disposal ability of whole reaction system.
As shown in Figure 1, the column plate 4 of a level is set in the middle of the reactor wall 2, column plate has a downward downspout 5 and a riser 6 upwards, form first stage reactor 3.
Column plate 4 has an axial conical section 7, be the riser 6 that gas rises in the middle of cone, ring section 8 is connected on contiguous reactor wall 2 obliquely.Column plate can stop liquid, and liquid level 9 depends on the height of downspout 5 on column plate 4.Every block column plate is all equipped with containing sulfonic ion exchange resin as DZH large porous strong acid resin particle 10.Ion-exchanging particles on column plate is stirred into suspension in a liquid.Leading to liquid to prevent ion-exchanging particles to let out from downspout 5 together, in downspout upper end, guard 12 being installed.The angle requirement of cone 7 and ring section 8 is more than or equal to DZH large porous strong acid resin or the dwell angle of other solid esterification catalyst particle on esterification column plate 4 in liquid.
Be connected to the main air entraining pipe of cross around cone riser, the air-flow risen in riser 6 enters main air entraining pipe, then to an annular air entraining pipe, through fish gill formula gas distributor, upflowing vapor is separated into bubble 11 after entering reaction mass.
In Fig. 1,16 is the downspout that upper block column plate comes.The liquid level 17 of downspout 16.The pressure that on column plate liquid level, height H is produced by liquid level and the distributor thereof of lastblock column plate adds what fricative pressure determined.
When reactor operation, unitary, binary or polybasic carboxylic acid or its mixture contact with the alcohol steam counter-flow of rising with liquid form.Every block column plate is all the esterification district that esterification catalyst is housed separately, under the effect of catalyst, all carries out esterification and the water of removing esterification generation simultaneously.The water that esterification generates in the reactor is vaporized by the alcohol steam risen and is entrained to the top of reactor.Liquid phase stream through reactor time, when liquid phase falls next block column plate from one block of column plate liquid phase acid concentration liquid more and more lower, again on column plate with more and more drying alcohol steam contact.Make molecular balance move to producing the direction of ester by this method, moisture reduction gradually in the process simultaneously declined on column plate along with liquid phase, effectively inhibits the back reaction that ester is hydrolyzed mutually.
By the design of the liquid residence time to the number of plates in reactor and every fast column plate, require to make the carboxylic acid content in bottom product be less than 1mol%.By providing enough alcohol steam, driving a reaction liquid produces and laterally stirs, and the bubble simultaneously risen 11 pairs of suspension carry out radial direction and stir, and effectively ensure that the suspended state of acid-exchange resin particulate in suspension in liquid phase circulation.The inclination angle of inclined plane of cone 7 and ring section 8 to the inclined downward of distributor, to make not having obvious resin to stagnate below suspension.If needed, can add inert gas in ascending air, what usually add is byproduct of reaction ether.Such as acidic catalyst can promote that alcohol reacts and generate ether.Methyl alcohol is used to use ethanol for can diethyl ether be generated during raw material for can dimethyl ether be generated during raw material.These two kinds may be used to ensure the liquid suspension on column plate or the water for taking away esterification generation.
What Fig. 2 described is main air entraining pipe 13 and the distribution situation of an air entraining pipe 14 on tower tray, props up an air entraining pipe and can arrange suitable number according to reactor scale.
What Fig. 3 described is air entraining pipe cross-sectional structure schematic diagram, represents structure and the working stock of fish gill formula gas distributor.Air entraining pipe 20 outside suit membrane casing 21, suitable notch 22 is offered in air entraining pipe 20 bottom, and the membrane casing of establishing of the edge on the long limit of notch 22 arranges scarfing 23.In working order, gas sprays via the notch 22 of air entraining pipe, and under the effect of air-flow shear stress, the scarfing 23 of membrane casing opens, and air dispersion is that minute bubbles enter reaction bed.Air-flow forms turbulent flow in scarfing exit, and turbulent flow is to scarfing place transverse shearing stress, and the size of shear stress is fixed through the gas quick decision of scarfing by gas flow, and this shear stress supports scarfing and opens, and fragmentation is played to bubble in this turbulent area simultaneously.The folding situation of scarfing is determined by gas quick decision, and gas speed is determined by inlet amount and tower pressure drop, thus scarfing openings of sizes along with tower pressure drop enhancing, weaken and change, when tower pressure drop strengthens, opening becomes large; Openings get smaller when tower pressure drop reduces, when gas flows out, bubble diminishes; When not having gas to flow out, scarfing closes, and effectively prevents reactant liquor suck-back, and avoids catalyst to drain on next block column plate.Effectively reduce air-flow washing away catalyst granules by the effect of scarfing, improve the service life of catalyst.
Theoretical cam curve in reactor and number of actual plates are not must be consistent, and the theoretical cam curve of reactor may change along with the change of acid in charging, if the acid in charging changes, the acid content in methyl esters product at the bottom of tower also may change.
Mention esterification byproduct above usually like the ether of binary.The yield of accessory substance ether depends on the operating temperature of reactor.Therefore the operating temperature reducing reactor can reduce the generation of any accessory substance.But the conversion ratio of temperature lower acid generation ester is lower in theory.Need conversion ratio ester phase product being added to the method raising ester phase that excessive alcohol reacts again under these conditions.Ester usually containing 97mol% to 99mol% in ester phase product and number acid raw material, the mixing mol ratio adding excessive alcohol (as methyl alcohol) alcohol and ester is as 3:1 between 2:1 to 4:1.
Concerning majority reaction, acid or monoesters are downward liquid phase stream and alcohol is the vapor stream risen.Boiling point as tartaric acid or monoesters is lower than alcohol, and so alcohol and acid (or monoesters) component can be exchanged, and be alcohol are liquid phase, from the column plate of reactor to dirty and sour (or monoesters) steam then upwards with alcohol counter current contacting.
Method of the present invention and effect is further illustrated below by embodiment.The percentage composition related to is molar content.
Embodiment
Use for laboratory reactor, internal diameter is 60mm, and material is glass, installs 10 blocks of column plates in reactor up and down.Reactor insulation is also heated by outside ribbon heater.Every block column plate has independently temperature-controlling system.First piece of column plate (column plate of topmost) is as washing column plate not loaded resin.Second block of column plate is as the charging aperture of acid starting material.All the other 8 blocks of column plates are all equipped with a certain amount of strong acid ion exchange resin.The column plate of loaded resin catalyst is arranged rotary gas distributor 1 as shown in Figure 2.Methyl alcohol is heated to 150 DEG C, and methanol steam enters reactor by the column plate of reactor lowermost end.Every fast column plate there is 200ml liquid.On column plate, resin loadings is calculated as 18% of liquid weight on column plate with dried resin.The water that reaction overhead gas contains unreacted methyl alcohol, esterification generates and a small amount of accessory substance dimethyl ether are cooled.Usual tower head installs liquid flooding device to control the ester product loss rate in reactor.
Reactor is opened when making and is used dodecanoate loaded resin.Phase reactor charging is started, containing the myristic acid of 50mol% laurate, 40mol% laurate and 10mol% in material after the methanol steam on every block column plate and temperature are all stablized.The product ester of reactor bottom is monitored, until reach molecular balance.Liquid phase analysis on different column plate the results are shown in following table 1; Column plate is numbered 1 to 10 from top to bottom, and the column plate of tower top is No. 1, and the column plate at the bottom of tower is No. 10.
Table 1 embodiment reaction effect.
| Alcohol: sour mol:mol | 5：1 | 4：1 | 3：1 |
| Total residence time hour | 3 | 2.5 | 2.0 |
| Column plate number | The concentration mol% of ester | The concentration mol% of ester | The concentration mol% of ester |
| 5 | 99.72 | 99.04 | 98.29 |
| 6 | 99.91 | 99.42 | 98.98 |
| 7 | 99.98 | 99.89 | 99.61 |
| 8 | 100.00 | 99.97 | 99.87 |
| 9 | 100.00 | 100.00 | 99.96 |
| 10 | 100.00 | 100.00 | 100.00 |
| Dimethyl ether by-product rate mol% | 2.0 | 1.5 | 0.6 |
Table 2 comparative example reaction effect.
| Alcohol: sour mol:mol | 5：1 | 4：1 | 3：1 |
| Total residence time hour | 3 | 2.5 | 2.0 |
| Column plate number | The concentration mol% of ester | The concentration mol% of ester | The concentration mol% of ester |
| 5 | 98.02 | 95.21 | 94.87 |
| 6 | 99.21 | 98.35 | 96.83 |
| 7 | 99.55 | 98.73 | 96.98 |
| 8 | 99.73 | 98.95 | 97.52 |
| 9 | 99.89 | 99.26 | 98.94 |
| 10 | 99.92 | 99.47 | 99.15 |
| Dimethyl ether by-product rate mol% | 3.5 | 3.2 | 1.9 |
Comparative example
By the equipment and process condition identical with embodiment, just gas distributor is offered common aperture on being and is distributed to gas, and reaction effect is in table 2.
Claims (10)
1. an esterifier, comprise tower-like reactor shell, at least one deck column plate is installed in housing, solid esterification catalyst bulk storage is on column plate, downspout through column plate and riser are set, liquid level on downspout upper end open and column plate is suitable, downspout lower openings stretches into below adjacent lower column plate liquid level, riser is communicated with gas distributor in the position on column plate top, it is characterized in that: gas distributor is fish gill formula gas distributor, gas distributor is made up of air entraining pipe and the fish gill formula distribution of gas mouth be distributed on air entraining pipe, air entraining pipe is connected on riser, air entraining pipe the latter half cylinder is arranged the notch of inclination, cover film sleeve pipe outside notch, the edge on the corresponding long limit of air entraining pipe notch of membrane casing has scarfing, described scarfing is for cut open membrane casing at desired location place, do not need to slice off any position.
2. according to reactor according to claim 1, it is characterized in that: air entraining pipe comprises main air entraining pipe and an air entraining pipe, and main air entraining pipe is Straight, and main air entraining pipe is communicated with riser, propping up air entraining pipe is spirally coiled or Straight, and an air entraining pipe is communicated with on main air entraining pipe.
3. according to reactor according to claim 1, it is characterized in that: the distance of air entraining pipe and column plate is 100mm ~ 500mm, the inclined notch on air entraining pipe is bar shaped, and the width of notch is greater than 1.5mm, and the length of notch is 5% ~ 30% of air entraining pipe girth; The angle of inclination of notch is 15 ~ 75 degree.
4. according to reactor according to claim 1, it is characterized in that: the distance of air entraining pipe and column plate is 100mm ~ 200mm, the inclined notch on air entraining pipe is bar shaped, and the width of notch is 2 ~ 20mm, and the angle of inclination of notch is 30 ~ 50 degree.
5. according to reactor according to claim 1, it is characterized in that: the scarfing of the membrane casing covered outside air entraining pipe notch is arranged on the edge on the long limit of air entraining pipe notch, scarfing is arranged on the edge on any one long limit in two long limits of air entraining pipe notch.
6. according to the reactor described in claim 1 or 5, it is characterized in that: the length of scarfing is 70% ~ 150% of air entraining pipe notch length.
7. according to reactor described in claim 1 or 5, it is characterized in that: the material of the membrane casing covered outside air entraining pipe notch is that corrosion resistant alloy foil sheet is made, or for non-metal anti-corrosion material is made, or make for the composite film material of alloy and non-metal anti-corrosion material.
8. according to reactor according to claim 1, it is characterized in that: column plate quantity is 3 ~ 50 pieces.
9. the production method of a dimethyl maleate, it is characterized in that using the esterifier described in the arbitrary claim of claim 1 to 8, with monomethyl maleate and methyl alcohol for raw material, take storng-acid cation exchange resin as catalyst, monomethyl maleate is introduced from reactor head with liquid form, methyl alcohol is introduced from reactor bottom with gas phase, arranges 10 ~ 40 pieces of sieve plates in reactor, obtains dimethyl maleate and draw reactor from reactor bottom after reaction.
10. in accordance with the method for claim 9, it is characterized in that: the concrete reaction condition that dimethyl maleate is produced is: the mol ratio 1:1.5 ~ 1:5 of maleic acid mono alkyl ester/alkylol, the cumulative volume air speed of liquid phase feeding to resin catalyst of maleic acid mono alkyl ester is 0.2h-1 ~ 2.0h-1, reaction temperature is 90 DEG C ~ 160 DEG C, and reactor bottom inlet steam pressure limit is 0.1MPa to 3MPa.
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| CN101254444A (en) * | 2007-12-05 | 2008-09-03 | 南京大学 | Catalytic reaction, rectification integrated technique and special-purpose equipment |
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