CN101805272B - Method for preparing isocyanate by interface phosgenation reaction - Google Patents

Method for preparing isocyanate by interface phosgenation reaction Download PDF

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CN101805272B
CN101805272B CN 201010152140 CN201010152140A CN101805272B CN 101805272 B CN101805272 B CN 101805272B CN 201010152140 CN201010152140 CN 201010152140 CN 201010152140 A CN201010152140 A CN 201010152140A CN 101805272 B CN101805272 B CN 101805272B
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reaction
reactor
liquid
phosgene
phosgenation
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CN101805272A (en
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华卫琦
孙中平
尚永华
石滨
李建峰
薛永和
孙辉
王海影
王伦鹏
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Wanhua Chemical Group Co Ltd
Wanhua Chemical Ningbo Co Ltd
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Ningbo Wanhua Polyurethanes Co Ltd
Wanhua Chemical Group Co Ltd
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Abstract

The invention discloses a method for preparing isocyanate by an interface phosgenation reaction, which comprises the following steps: (a) injecting solution flow of polyamine having a general formula(II) and liquid flow of phosgene after flowing through respective mixer into a first-stage reactor at a contact included angle of 30-180 degrees, enabling the solution flow of polyamine to contact and mix with the liquid flow of phosgene and carrying out a phosgenation reaction on the interface; (b) enabling the obtained phosgene solution to enter a second-stage reactor for continuously carrying out the phosgenation reaction to obtain phosgene solution containing isocyanate; and (c) separating and purifying the phosgene solution containing isocyanate to obtain an isocyanate product. The invention shortens the time of the phosgenation reaction and improves the phosgenation yield and the phosgene solution quality; and in addition, the concentration of the isocyanate in the obtained phosgene solution can reach 25-40 percent by weight, so the invention has favorable industrial value.

Description

A kind of method for preparing isocyanic ester by interface phosgenation reaction
Technical field
The present invention relates to the preparation method of isocyanic ester, more particularly, is a kind of method for preparing isocyanic ester by interface phosgenation reaction.
Background technology
As everyone knows, the amine photoreactive gas can prepare isocyanic ester, and according to the type of amine, reaction with gas phase or liquid phase intermittently or carry out (W.Sie fken, Liebigs Ann.562,75(1949)) continuously.From bibliographical information, phosgenation prepares isocyanic ester and mainly adopts vapor phase process and liquid phase method two class technologies, and they have advantage separately.
It is the emphases method of developing at present that vapor phase process prepares isocyanic ester, and as far back as the forties in 20th century, just existing gas phase phosgenation method prepares the report (Siefken, Annalen562,108,1949) of isocyanic ester.Gas phase reaction process usually carries out in tubular reactor.Gas phase reaction process is a rapid reaction process, requires mixing rate to want fast, will avoid high-temperature coking simultaneously as far as possible.In high temperature gas phase phosgenation reaction process, amine and isocyanic ester overstand under 300-500 ℃ of high temperature is extremely unsettled, can take place such as sloughing NH 2, the NCO group decomposition reaction.In gas-phase process, after high temperature gas phase photoinitiator chemical skill, operation such as still need pass through thermal response, aftertreatment and separate.
The process that gas phase phosgenation prepares isocyanic ester belongs to the high temperature phosgenation reaction, owing to be to react under gas phase state, it has fast and well mixing, has reduced the influence of hydrogenchloride, reduces the formation of superpolymer such as by product urea.Yet because speed of response is very fast, hydrogenchloride is accelerated equally with the speed that the amine reaction generates hydrochloride, and therefore, the high temperature phosgenation reaction is a large amount of hydrochloride material of generation easily, causes in the product foreign matter content higher.Equally, owing to phosgenation reaction at high temperature carries out, very high for the material requirement of required equipment.In view of above-mentioned high temperature gas phase method in the limitation of preparation aspect the isocyanic ester, this method does not prepare in the isocyanic ester field at phosgenation as yet is used widely, only be that Bayer A.G and Yantai ten thousand China had relevant report, related products also only limits to TDI and part A DI product.
It is the most ripe operational path that the liquid phase phosgenation prepares isocyanic ester, comprises operational paths such as salify liquid phase method, direct liquid phase method and pressurization liquid phase method.Because phosgenation reaction is rapid reaction, has emphasized the influence of mixing and hydrogenchloride in the liquid phase reaction course.Salt forming method is mainly considered the protection of amido, and directly liquid phase method has mainly been considered mixing of amido and phosgene.
GB1142628 has set forth the technology that hydrochloride prepares isocyanic ester, but when the hydrochloride transformation efficiency is higher than 95%, required long reaction time, cause yield to descend, the salify transformation efficiency is lower than 30%, and then unreacted HDA is many, though can shorten the reaction times, easy and HDI reaction generates ureas impurity.
US5523467 has set forth employing ester class and has carried out the salify phosgenation reaction as solvent, by appending nitrogen in the reaction process, prevented that HDI and urea chloride from generating tarry matters, improved the yield of phosgenation reaction, shortened the reaction times, made salt-forming reaction progressively have commercial viability.But because the increase of nitrogen has increased process cost, improved the cost of unit product, compared other processing methodes, still there are shortcomings such as yield is low, timeliness is low in it.
US4581174 has described by the phosgenation of primary amine in the mixed cycle and has prepared organic single and/or polyisocyanates continuously, and part recirculation contains the reaction mixture of isocyanic ester, and the ratio of HCl is less than 0.5% in the mixture of recirculation.Equally, this isocyanic ester is recycled to the formation that has also promoted urea in the reaction zone that contains unhindered amina really continuously. and the urea of precipitation injures the stable operation of this method.
CN101056847 has set forth employing ether and has made solvent, can form salt-melting with hydrogenchloride, to isolate hydrogenchloride, to improve yield and the efficient of reaction.Wherein use can with hydrogenchloride form salt-melting and can be reversibly by its compound that discharges hydrogenchloride again as solvent.The solvent that can temporarily form salt-melting with the hydrogenchloride of formation in the reaction is ether and polyethers.
US5136086 has described and has utilized carboxylicesters as the solvent of amine and phosgene reaction.The shortcoming of this scheme is solvent meeting and isocyanate reaction.Preparing in the process of isocyanic ester by corresponding amine and phosgene reaction, ever-present requirement is the minimizing that reaches phosgene amount in the reaction system; Ever-present another requirement is to reduce side reaction also therefore to obtain higher yields and have the purpose product that improves quality in the polyisocyanates preparation.The document proposes, under the condition of amine and phosgene reaction, and when using can form the solvent of salt-melting with formed hydrogenchloride the time temporarily, the space-time yield raising of this method and significantly suppress side reaction.
In the phosgenation reaction process, the phosgene concentration in containing the photochemical liquid of isocyanic ester also is a very important influence factor.CN1163608 has set forth the method that adopts continuous processing to prepare isocyanic ester under the pressure of 1-30 bar, and the concentration that phosgene is dissolved in the photochemical liquid that contains isocyanic ester is higher, can obtain corresponding isocyanic ester.Under these processing condition, the phosgene concentration around the amido is improved, and makes the molar ratio of its phosgene and amine reach 3:1-4:1.
In sum, prepare in the reaction process of isocyanic ester at phosgenation, hydrogenchloride is very big to the reaction process influence, not only cause quality product to descend, and may cause amido hydrochloride solid increase in the reaction process, and then cause reactor plugs, and caused the increase of by product in the isocyanic ester, the phosgenation yield descends.Therefore, in isocyanic ester preparation technology's R﹠D process, need to control hydrogenchloride as far as possible to the influence of reaction process.
In addition, the phosgenation surface reaction has been set forth a kind of impact flow reactor that adopts as CN101235136 and has been carried out the method that interfacial prepares polycarbonate in that research has widely been arranged aspect the preparation carbonic ether.This method can improve the reaction efficiency of phosgene and phenates, shortens the reaction times, reduces side reaction product, reduces the energy consumption in the production process.But the phosgenation surface reaction still is not reported in the application in isocyanic ester field.
Summary of the invention
In order to overcome above-mentioned problems of the prior art, the object of the present invention is to provide a kind of novel interface phosgenation to prepare the method for isocyanic ester.
The present invention is based on following design: liquid phase phosgenation reaction process is the reaction of gas, liquid, solid three-phase system, and main product is urea chloride, amido hydrochloride, hydrogenchloride, isocyanic ester and by product etc.Required according to technological reaction, the by product of isocyanic ester such as amido hydrochloride is the product of not expecting, but because phosgenation reaction belongs to rapid reaction, the reaction of hydrogenchloride and amido belongs to rapid reaction equally, therefore, it is just unavoidable to generate the product that this class of amido hydrochloride do not expect.There have been a lot of patent documentations to mention, noted the hydrogen chloride content in the control phosgene and change the generation that solvent system is controlled hydrochloride.The present invention provides a kind of new processing method on the basis of existing technology, make phosgene stream carry out rapid reaction with amine aqueous solution stream, the hydrogenchloride that generates can be rejected from reactive system rapidly, thereby reduce hydrogenchloride as far as possible for the influence of phosgenation reaction; In addition, phosgene can also be back to proceeds phosgenation reaction in the reactor, reaction efficiency is improved significantly.
Surface reaction typically refers to the chemical reaction between out-phase (each surrounding medium).According to characteristic and lip-deep various chemical classes, content, existence and the character of surface in contact, and the various chemical reactions that take place under certain conditions.Gu there are liquid-liquid, solid-liquid, solid-gas, liquid-gas and solid-5 types in the interface of two-phase.Interface phosgenation reaction of the present invention refers to that amine and light gas-liquid flow form the interface under the assistance of mixed distribution device, the rapid reaction of carrying out, mainly occur in amine aqueous solution stream, the phosgene stream in the reaction system and the solid product that produces between on the formed interface.
Method by the isocyanic ester of interface phosgenation reaction preparation shown in general formula (I) provided by the present invention is as follows:
R(NCO) n (I)
R(NH 2) n (II)
Wherein R is aliphatics, alicyclic or aromatic hydrocarbyl, and has two carbon atom arrangement at least between any two adjacent (NCO) of general formula (I), and n 〉=2, and this method may further comprise the steps:
(a) the liquid flow point with the solution stream of polyamines of general formula (II) and phosgene is not flowed through behind separately the mixing tank, contact clip angle with the 30-180 degree is injected in the first step reactor, make the solution stream of polyamines contact, mix with the liquid stream of phosgene, and carry out phosgenation reaction at the interface;
(b) resulting photochemical liquid enters in the reactor of the second stage, proceeds phosgenation reaction, obtains containing the photochemical liquid of isocyanic ester;
(c) the photochemical liquid that contains isocyanic ester obtains isocyanate products after separating, purifying.
In method provided by the present invention, preferred R is aliphatics C2-C50 alkyl, alicyclic C2-C50 alkyl or aromatic series C6-C50 alkyl, further preferred R is aliphatics C4-C30 alkyl, alicyclic C4-C30 alkyl or aromatic series C6-C30 alkyl, and more preferably R is aliphatics C5-C18 alkyl, alicyclic C5-C18 alkyl or aromatic series C6-C20 alkyl.
In method provided by the present invention, preferred n=2-4, further preferred n=2 or 3.
In method provided by the present invention, the amine raw material that adopts is most amines with reactive behavior, suitable amine is to contain 2-15 carbon atom, preferred 3-15 carbon atom, aliphatics, alicyclic or aromatic series monoamine, two amines, three amines, tetraamine or five amines etc. of further preferred 4-13 carbon atom.For example, suitable aliphatie diamine has 1,4-butanediamine, 1, the 6-hexanediamine; Alicyclic diamine has 1,4-diamino-cyclohexane, 1-amino-3,3,5-trimethylammonium-5-amino methyl hexanaphthene or 4,4 '-dicyclohexyl methyl hydride diamines etc.; Suitable aliphatics triamine has 1,8-diamino-4-(aminomethyl) octane, triaminononane etc.Wherein, amine raw material of the present invention is preferred 1,6-hexanediamine, IPDA, H 12MDA and triaminononane.Suitable aromatic amine has phenylenedimethylidyne diamines, tolylene diamine, diaminobenzene, naphthylene diamine, 2,4 ' or 4,4 '-ditan diamines and isomer mixture thereof, for example, isomer proportion is 2 of 80/20-65/35,4-/2,6 tolylene diamine mixtures or pure 2, the 4-tolylene diamine.
The solution stream of polyamines of the present invention is the organic solution of one or more amine or amine; The liquid stream of described phosgene is pure phosgene liquid or phosgene solution.In the method for the invention, can utilize inert solvent that the amine photoreactive gas is diluted, with the liquid stream of the solution stream photoreactive gas that forms amine.Described inert solvent generally is selected from: one or more in benzene,toluene,xylene, chlorobenzene, naphthane, orthodichlorobenzene, santochlor, a chlordiphenyl, dimethyl terephthalate ester or the diethyl phthalate; Preferred chlorobenzene or orthodichlorobenzene.
In method provided by the present invention, prepared isocyanic ester can be to contain (the carbon atom in the isocyanate functional group) 2-15 carbon atom, preferred 3-15 carbon atom, aliphatics, alicyclic or aromatic series monoisocyanates, vulcabond, triisocyanate, tetraisocyanate or five isocyanic ester etc. of further preferred 4-13 carbon atom.For example, aliphatic diisocyanate has: 1,4-fourth vulcabond or hexamethylene diisocyanate; Alicyclic diisocyanate has: 1,4-cyclohexyl diisocyanate, 1-amino-3,3,5-trimethylammonium-5-methylcyclohexane diisocyanate, 4,4 '-dicyclohexyl methane diisocyanate etc.; The aliphatics triisocyanate has: 1,8-diamino-4-octane vulcabond, three nonyl isocyanic ester etc.; Wherein, preferred hexamethylene diisocyanate, IPDI, H 12MDI etc.Aromatic isocyanate has: xylylene diisocyanate, tolylene diisocyanate, PPDI, naphthalene diisocyanate, 2,4 ' or 4,4 '-diphenylmethanediisocyanate and isomer mixture thereof, for example, isomer proportion is 2 of 80/20-65/35,4-/2,6 tolylene diisocyanate mixtures or pure 2,4 toluene diisocyanate.
In method provided by the present invention, the solution stream of described polyamines and the liquid of phosgene stream contact angle between the mixing tank that angle refers to the mixing tank of polyamines solution stream and light gas-liquid flow, that is, polyamines solution stream and the angle of light gas-liquid flow before contacting, this angle is preferably the 45-135 degree.
In method provided by the present invention, preferably, in polyamines solution stream and two contact interfaces that flow thigh of light gas-liquid flow the mixed distribution device is set, and the sectional area of mixed distribution device accounts for 1/4-1/3 of still formula or tower reactor sectional area.Described mixed distribution device adopt filler distribution device, column plate sparger or tower tray sparger etc. all can, for example, filler distribution device, column plate sparger and the tower tray sparger etc. of huge northeast part of China chemical industry equipment company limited carry out at the interface to guarantee hybrid reaction.
In method provided by the present invention, described first step reactor also can be described as mixing reactor, and described second stage reactor also can be described as thermal reactor.Wherein, described mixing reactor can be this area tank reactor or tower reactor commonly used, preferred tank reactor; Further preferably, described mixing reactor (first step reactor) is that the processing requirement according to method provided by the present invention has been carried out necessary improvement to the internal structure of reactor on the basis of pre-existing reactors; The improvement of specific reactor structure aspects sees also the introduction of following embodiment part.Described thermal reactor (second stage reactor) is the popular response device for the preparation of isocyanic ester, and it also can be tower or tank reactor, and described thermal reactor also can be two thermal reactors of single thermal reactor or series connection.
Interface phosgenation reaction of the present invention occurs on liquid liquid, gas-liquid and the gas-solid interface, the mixolimnion that has produced when having taken full advantage of amine aqueous solution stream and light gas-liquid flow by separately mixing tank high speed ejection, simultaneously, the mixed distribution device auxiliary down, more be conducive to mixing of amine aqueous solution and light gas-liquid flow.Because phosgenation prepares the reaction of isocyanic ester and belongs to rapid reaction, can finish in the short period of time, therefore, be chosen on the interface and react, in the first step phosgenation reaction, obtain the urea chloride of higher yields, guaranteed that interface phosgenation reaction generates less impurity, its reaction times in 10-120 scope second, preferred 30-60 second.
In method provided by the present invention, surface reaction temperature in first step reactor (mixing reactor) is the 60-160 degree, be preferably the 80-130 degree, with the carrying out that guarantees that the first step phosgenation reaction of reaction mass first step reactor after the mixing tank ejection can be rapidly and efficiently.Generally speaking, the mol ratio through phosgene and amine in the photochemical liquid after the interface phosgenation reaction is 3:1-4:1.The photochemical liquid that obtains through interface phosgenation reaction enters follow-up thermal reactor by overflow port, carries out hot phosgenation reaction, and its temperature of reaction is the 90-150 degree, preferred 110-130 degree; Owing in the process of surface reaction, reduced the content of hydrogenchloride, reduce the content of solid amido hydrochloride, thereby reduced the thermal response residence time, improved the quality of reaction efficiency and product; Finally, photochemical liquid obtains isocyanate products by separation system.
Compared with prior art, beneficial effect of the present invention is mainly reflected in following aspect:
At first, because the present invention adopts the interface phosgenation to prepare isocyanic ester, the phosgenation reaction time be can shorten, phosgenation yield and photochemical liquid quality improved.
The photochemical liquid of the isocyanic ester that phosgenation reaction obtains, it is mainly is solvent, phosgene, hydrogenchloride, urea chloride, isocyanic ester and amido hydrochloride etc.Hydrogen chloride content is very low in the resulting photochemical liquid of employing the present invention, and owing to carry out the release of hydrogenchloride at the interface, under little condition of negative pressure, the residence time of hydrogenchloride in liquid phase is very short, remaining considerably less in liquid phase simultaneously, this is very beneficial for the process that phosgenation reaction prepares isocyanic ester.
Because it is slower that amido hydrochloride and phosgene reaction obtain the speed of isocyanic ester, thereby greatly reduce the efficient of phosgenation reaction.Along with reducing of hydrogenchloride in the unit volume, the probability that generates the amido hydrochloride reduces.Therefore, the present invention has created an environment that is unfavorable for that hydrogenchloride is residual, thereby has improved the efficient of phosgenation reaction.
In addition, the selection of temperature of reaction is considerable to the phosgenation reaction process.The present invention is under higher temperature of reaction, makes phosgene and amine generation rapid reaction, thereby has reduced the influence of hydrogenchloride to reaction process, has reduced the content of hydrochloride, has improved phosgenation reaction efficient, has finally obtained reaction effect preferably.
Because the phosgenation strength of solution is to determine whether operational path has one of important parameter of industrial value, and the photochemical liquid of high isocyanate concentration can obviously reduce the use of solvent, improves the spatiotemporal efficiency of phosgenation, improves the added value of whole phosgenation reaction.It is that the emphasis that develops just is that present vapor phase process prepares isocyanic ester: the isocyanate concentration that high temperature gas phase method obtains photochemical liquid can reach more than the 50wt%.Yet the isocyanate concentration of the photochemical liquid of salt forming method preparation is at 5-15wt%, and directly the isocyanate concentration of the photochemical liquid of liquid phase method preparation is at 15-25wt%; And can reach 25~40wt% by the isocyanate concentration that adopts the photochemical liquid that interface phosgenation reaction provided by the present invention obtains.Therefore, make method provided by the present invention have more industrial value than direct liquid phase method.
Description of drawings
Fig. 1 is the synoptic diagram of a kind of preferred implementation of method provided by the present invention.
As shown in Figure 1,1 mixing tank for amine aqueous solution stream, 2 is the mixing tank of light gas-liquid flow, and 3 is the mixed distribution device, and 4 is traverse baffle, and 5 is condenser, and 6 is little negative pressure system, and 7 is tank reactor.Wherein TG is that thermometer, PG are that pressure warning unit and M are electric motor (motors).
Embodiment
Below in conjunction with accompanying drawing, further describe method provided by the present invention, but therefore the present invention is not subjected to any restriction.
" amine " or " polyamines " or " amine aqueous solution " or " polyamines solution " can exchange use in this application, because amine is to react with the form of solution.
As shown in Figure 1, the liquid flow point of the solution stream of polyamines and the phosgene mixing tank 1 and 2 separately of not flowing through, contact clip angle with the 30-180 degree is injected in the tank reactor 7, make the solution stream of polyamines be in contact with one another, mix in mixed distribution device 3 places (reaction solution at the interface) with the liquid stream of phosgene, and carry out phosgenation reaction at the interface; Resulting photochemical liquid enters (not shown) in the thermal reactor in downstream, proceeds phosgenation reaction, obtains containing the photochemical liquid of isocyanic ester; The photochemical liquid that contains isocyanic ester obtains isocyanate products after separating, purifying.
Embodiment preferred according to the present invention, described tank reactor 7 is furnished with condensing heat exchanger 5 (being also referred to as condenser), and the outlet of described condensing heat exchanger links to each other with little negative pressure system 6.Like this, under little condition of negative pressure, the hydrogenchloride that generates in the interface phosgenation reaction can be withdrawn from tank reactor rapidly, reduces hydrogenchloride to the influence of reaction.Certainly, when the hydrogenchloride that will generate is taken away, also can take the excessive phosgene of part simultaneously away from this reactor.Owing to be furnished with condenser, after phosgene is condensed, can return tank reactor 7 through reflux pipeline in condenser.Like this, not only avoid the volatilization of phosgene, and can participate in phosgenation reaction again after phosgene is refluxed, improved the efficient of reaction.Described little negative pressure system can produce the negative pressure that is conducive to withdrawing gas from condenser, and generally this negative pressure is-5 to-30KPa.
Another embodiment preferred according to the present invention, in order to improve the backflow effect of phosgene, except process pipeline and accessory that above-mentioned condenser, little negative pressure system and necessity are set, the below that is preferably in first step reactor (tank reactor 7) inner condenser refluxing opening arranges one or more traverse baffles, and wherein the traverse baffle of below is arranged on below the liquid level of surface reaction.Particularly, when a traverse baffle only was set, described traverse baffle was fixed on condenser refluxing opening below, is positioned at below the liquid level simultaneously; When a plurality of traverse baffle was set, a plurality of traverse baffles arranged in parallel to each other, and were basically parallel to the liquid level (being horizontally disposed with) of surface reaction, and the traverse baffle of below is under liquid level.The traverse baffle that in first step reactor, appends, it is similar to the column plate of distillation tower in function, and best described traverse baffle offers many perforation, make the hydrogenchloride in the phosgene of condensing reflux volatilize fully, the phosgene of Hui Liuing can enter the phosgenation reaction process simultaneously, and it is perfect preferably that phosgenation reaction is obtained.
In the present invention, the cross-sectional shape of described traverse baffle is circle, trilateral, rectangle, rhombus, trapezoidal, equilateral polygon, non-equilateral polygon or ellipse etc., circular, trilateral or rectangle.The position of traverse baffle be installed in condenser condensate outlet under, directly do not fall on the liquid level of first step reactor from the phlegma of condenser guaranteeing, but drop on the traverse baffle.The sectional area of traverse baffle major surfaces accounts for (comprising perforated area) 5-15% of first step cross-sectional reactor area.In each traverse baffle, be typically provided with 5-200 perforate, preferred 10-150 perforate.
In the present invention, by the hydrogenchloride that heat exchange condensers obtains, can adopt absorption process to prepare technical hydrochloric acid, also the hydrogenchloride that obtains can be carried out oxidation and prepare chlorine, for example by electrolytic oxidation, thereby separate recycling of the hydrogenchloride that obtains in the realization response process.The hydrogenchloride that obtains by the present invention does not influence the quality of later stage product.
Interface phosgenation reaction provided by the present invention prepares the method for isocyanic ester and mainly divides two stages to carry out.In the fs of phosgenation reaction, amine and phosgene reaction obtain corresponding urea chloride, hydrogenchloride and amido hydrochloride.Reaction between amine and the phosgene is very fast, and is strong heat release.In order farthest to reduce the formation of by product and solid, amine must mix rapidly under the solvent condition with phosgene, and such first phosgenation stage usually needs to adopt mixing tank, and described mixing tank nozzle normally.Material amine photoreactive gas enters through mixer outlet and carries out phosgenation reaction in the reactor.The preferred mixing tank that adopts is tubular type, Venturi tube, ring-type annular space nozzle, micro-mixer etc., and these mixing tanks have report more in phosgenation prepares the patent documentation of isocyanic ester.The present invention adopts this type of mixing tank, and being conducive to phosgene and amine has hybrid reaction preferably, is conducive to the reaction process of phosgenation simultaneously.
In method provided by the present invention, described smooth gas-liquid flow is with 3-30m/s, and the flow velocity of preferred 8-18m/s enters into first step reactor from light gas-liquid flow mixer outlet; Meanwhile, amine aqueous solution flows with 3-30m/s, and the flow velocity of preferred 8-18m/s enters into first step reactor from amine aqueous solution stream mixer outlet, thereby makes phosgene stream and amine fluid that very fast velocity of shear be arranged, and guarantees the carrying out of phosgenation reaction.
Can be used for the mixing tank of the present invention except already mentioned above, the novel mixing tank that has disclosed in the following prior art also can be used for the present invention: dynamic mixer, for example agitator, turbine or rotor-stator system; Static mixer, Kenic mixing tank for example, Scha schli mixing tank or SMV mixing tank; Jet mixer, for example nozzle or T mixing tank.In addition, can be used for mixing tank of the present invention also comprises: nozzle, for example narrow annular channel nozzle, annular die nozzle, steadily spray mixing nozzle, blowing-type injection nozzle, jet chamber, angle nozzle, triple flow nozzle, adverse current mixing section, Pitot nozzle and mixing nozzle; On-line mixing device, centrifugal mixing pump, tubular reactor or microstructure mixing tank etc.The outlet of above-mentioned mixing tank be shaped as circle, trilateral, ellipse, tetragon, rectangle and rhombus etc. all can, preferred ellipse or rectangle.
Below will carry out more detailed elaboration by the present invention of embodiment, but following examples can not be interpreted as the restriction to content of the present invention.
Embodiment 1
Embodiment 1-3 all adopts tank reactor as first step reactor, this reactor is furnished with condenser and little negative pressure system of linking to each other with condenser (select little negative pressure for-10kpa) and be installed in phosgene phlegma refluxing opening below in this reactor the traverse baffle with 30 perforation (its area account for reactor cross section long-pending 7%), three layers of traverse baffle of parallel installation, its lowermost layer is below liquid level, and the second stage reactor that adopts is conventional tank reactor.
Compound concentration is the tolylene diamine solution of 30wt%, is made up of the orthodichlorobenzene of 70 weight % and the tolylene diamine of 30 weight %; The tolylene diamine solution stream of flow 100kg/h enters in the tank reactor through the outlet of separately tube mixer respectively with the speed of 12 meter per seconds with the light gas-liquid flow of the speed of 12 meter per seconds and 95kg/h.These two stream thighs high speed under the contact angles of 90 degree contacts and mixes in this reactor, is under about 90 conditions of spending surface reaction to take place in temperature of reaction, and its reaction times is 40 seconds; Through behind the tank reactor, the photochemical liquid that has obtained having certain tolylene diisocyanate concentration, this photochemical liquid enters into the reaction that 120 ℃ thermal reactor is finished isocyanic ester via overflow port; Purify through separation system then, obtain the pure product of tolylene diisocyanate.
By for the monitoring analysis of reaction process as can be known, obtain through surface reaction that hydrochloride content is 3.2wt% in the photochemical liquid, the carbamyl cl content is 85.3wt%, toluene diisocyanate content is 11.5wt%; In the photochemical liquid that obtains by thermal reactor, tolylene diisocyanate concentration is 41.9wt%, and the yield that finally obtains tolylene diisocyanate is 97.9%.
Embodiment 2
In the present embodiment, compound concentration is the tolylene diamine solution of 20wt%, is made up of the orthodichlorobenzene of 80 weight % and the tolylene diamine of 20 weight %; The tolylene diamine solution stream of flow 100kg/h enters into tank reactor via the outlet of separately nozzle mixer with the light gas-liquid flow of the speed of 12 meter per seconds and flow 64kg/h respectively with the speed of 10 meter per seconds, these two stream thighs high speed under the contact angles of 70 degree contacts and mixes in this reactor, be about under 70 conditions of spending in temperature of reaction then and carry out interface phosgenation reaction, its reaction times is 42 seconds, through behind this reactor, the photochemical liquid that has obtained having certain isocyanate concentration; It is the reaction that 120 thermal reactors of spending are finished isocyanic ester that photochemical liquid enters into temperature of reaction via overflow port; Purify through separation system then, obtain the pure product of tolylene diisocyanate.
By for the monitoring analysis of reaction process as can be known, in the photochemical liquid that obtains through surface reaction, its hydrochloride content is at 2.8wt%, and the carbamyl cl content is 91.7wt%, and toluene diisocyanate content is 5.5wt%; In the photochemical liquid that obtains by thermal reactor, tolylene diisocyanate concentration is 27.98wt%, and the yield that finally obtains tolylene diisocyanate is 98.4%.
Embodiment 3
In the present embodiment, compound concentration is the hexanediamine solution of 18wt%, formed by the orthodichlorobenzene of 82 weight % and the hexanediamine of 18 weight %, the hexanediamine solution stream of flow 100kg/h enters into tank reactor via the outlet of separately nozzle mixer with the light gas-liquid flow of the speed of 14 meter per seconds and 80kg/h respectively with the speed of 13.6 meter per seconds, these two stream thighs high speed under the contact angles of 90 degree contacts and mixes in this reactor, temperature of reaction be 80 the degree conditions under interface phosgenation reaction takes place, its reaction times is 40 seconds, through behind this reactor, the photochemical liquid that has obtained having certain isocyanate concentration; It is that reaction is proceeded and finished to 130 thermal reactors of spending that photochemical liquid enters into temperature of reaction via overflow port; Purify through separation system then, obtain the pure product of hexamethylene diisocyanate.
By for the monitoring analysis of reaction process as can be known, obtain in the photochemical liquid through surface reaction, its hydrochloride content is at 12.3wt%, and the carbamyl cl content is 84.9wt%, and hexamethylene diisocyanate content is 2.8wt%; In the photochemical liquid that obtains by thermal reactor, hexamethylene diisocyanate concentration is 25.2wt%, and the yield that finally obtains hexamethylene diisocyanate is 96.7%.
Comparative Examples 1
This Comparative Examples adopts traditional still formula phosgenation to prepare isocyanic ester.Compound concentration is the tolylene diamine solution of 30wt%, formed by the orthodichlorobenzene of 70 weight % and the tolylene diamine of 30 weight %, the tolylene diamine solution stream of flow 100kg/h enters into tank reactor with the light gas-liquid flow of the speed of 12 meter per seconds and 95kg/h with the speed of 12 meter per seconds and mixes and the cold light gasification reaction, obtained having the photochemical liquid of certain isocyanate concentration, this photochemical liquid enters into the two levels of thermal reactor that temperature of reaction is respectively 100 degree and 120 degree continuously, finish the reaction of isocyanic ester, purify through separation system then, obtain the pure product of tolylene diisocyanate.
By for the monitoring analysis of reaction process as can be known, in the cold light gasification reaction, the viscosity of photochemical liquid is very big, needs could continue to react through cleaning; In the photochemical liquid that process cold light gasification reaction obtains, its hydrochloride content is 50.3wt%, and the carbamyl cl content is 45.3wt%, and toluene diisocyanate content is 4.4wt%; Behind the thermal reactor by two-stage, the concentration of tolylene diisocyanate is 39.08wt% in the resulting photochemical liquid, and the yield that finally obtains tolylene diisocyanate only is 91.8%.
Comparative Examples 2
This Comparative Examples adopts traditional still formula phosgenation to prepare isocyanic ester.Compound concentration is the tolylene diamine solution of 20wt%, formed by the orthodichlorobenzene of 80 weight % and the tolylene diamine of 20 weight %, the tolylene diamine solution stream of flow 100kg/h enters into tank reactor with the light gas-liquid flow of the speed of 12 meter per seconds and 64kg/h with the speed of 10 meter per seconds and mixes and the cold light gasification reaction, obtained having the photochemical liquid of certain isocyanate concentration, this photochemical liquid enters into temperature of reaction 100 degree and the 120 two levels of thermal reactors of spending respectively continuously, after proceeding and finishing the reaction of isocyanic ester, photochemical liquid is purified through separation system, obtains the pure product of tolylene diisocyanate.
By for the monitoring analysis of reaction process as can be known, in the photochemical liquid that obtains through surface reaction, its hydrochloride content is at 47.23wt%, and the carbamyl cl content is 50.06wt%, and toluene diisocyanate content is 2.71wt%; In the photochemical liquid that obtains by thermal reactor, the concentration of its tolylene diisocyanate is 26.51wt%, and the yield that finally obtains tolylene diisocyanate is 93.4%.

Claims (22)

1. method by the interface phosgenation reaction preparation isocyanic ester shown in general formula (I),
R(NCO) n (I)
R(NH 2) n (II)
Wherein R is aliphatics, alicyclic or aromatic hydrocarbyl, and has two carbon atom arrangement at least between any two adjacent (NCO) of general formula (I), and n 〉=2, said method comprising the steps of:
(a) the liquid flow point with the solution stream of polyamines of general formula (II) and phosgene is not flowed through behind separately the mixing tank, contact clip angle with the 30-180 degree is injected in the first step reactor, the solution stream of polyamines is contacted with the liquid stream of phosgene, mix, and carry out phosgenation reaction at the interface, the time of the liquid stream interface reaction of the solution stream of described polyamines and phosgene is 10-120 second, the surface reaction temperature is the 60-160 degree, described first step reactor is the following improved tank reactor of process: described tank reactor is furnished with condensing heat exchanger, and the outlet of described condensing heat exchanger links to each other with little negative pressure system;
(b) resulting photochemical liquid enters in the reactor of the second stage, proceeds phosgenation reaction, obtains containing the photochemical liquid of isocyanic ester;
(c) the photochemical liquid that contains isocyanic ester obtains isocyanate products after separating, purifying.
2. in accordance with the method for claim 1, it is characterized in that: the liquid stream of the solution stream of described polyamines and phosgene is flowed through behind separately the mixing tank, goes into first step reactor with the contact clip subscript of 45-135 degree.
3. it is characterized in that in accordance with the method for claim 2: place, the contacted horizontal section of described polyamines solution stream and light gas-liquid flow arranges the mixed distribution device.
4. method according to claim 3 is characterized in that, described mixed distribution device is filler distribution device, column plate sparger or tower tray sparger.
5. according to any described method among the claim 1-4, it is characterized in that: described second stage reactor is tank reactor or tower reactor.
6. it is characterized in that in accordance with the method for claim 5: the below of the refluxing opening of the condensing heat exchanger in the tank reactor in described step (a) arranges one or more traverse baffles.
7. in accordance with the method for claim 6, it is characterized in that: when a traverse baffle was set, described traverse baffle was fixed on the below of the refluxing opening of condensing heat exchanger, was positioned at simultaneously below the liquid level of surface reaction; When a plurality of traverse baffle was set, a plurality of traverse baffles were horizontally disposed with in parallel to each other, and were basically parallel to the liquid level of surface reaction, and nethermost traverse baffle is under the liquid level of surface reaction.
8. it is characterized in that in accordance with the method for claim 7: the cross-sectional shape of described traverse baffle is circle, equilateral polygon, non-equilateral polygon or ellipse; The sectional area of described traverse baffle major surfaces accounts for the 5-15% of first step cross-sectional reactor area; Be equipped with 5-200 perforate on each traverse baffle.
9. method according to claim 7 is characterized in that: the cross-sectional shape of described traverse baffle is circle, trilateral, rectangle, rhombus or trapezoidal; The sectional area of described traverse baffle major surfaces accounts for the 5-15% of first step cross-sectional reactor area; Be equipped with 10-150 perforate on each traverse baffle.
10. according to claim 1 or 9 described methods, it is characterized in that: the excessive phosgene of the hydrogenchloride that generates in the interface phosgenation reaction and part is withdrawn from first step reactor under the effect of little negative pressure rapidly, phosgene is condensed after the condensing heat exchanger condensation, and returns in the first step reactor via the condensing reflux pipeline.
11. in accordance with the method for claim 10, it is characterized in that: the phosgene logistics of returning first step reactor via the condensing reflux pipeline drops onto on the traverse baffle of one or more perforates, so that the hydrogenchloride of carrying secretly in the phosgene logistics that refluxes volatilizees fully.
12. according to claim 1 or 11 described methods, it is characterized in that: the time of the solution stream of first step reactor polyamines and the reaction of the liquid stream interface of phosgene is 30-60 second; The surface reaction temperature is the 80-130 degree; Temperature of reaction in the reactor of the second stage is the 90-150 degree.
13. method according to claim 12 is characterized in that: the temperature of reaction in the reactor of the second stage is the 110-130 degree.
14. according to claim 1 or 8 described methods, it is characterized in that: the mixing tank of the mixing tank of described polyamines solution stream and light gas-liquid flow is selected from: tube mixer, venturi mixer, annular space mixing tank, nozzle or micro-mixer; And described mixer outlet be shaped as circle, trilateral, ellipse, tetragon.
15. according to claim 1 or 8 described methods, it is characterized in that: the mixing tank of the mixing tank of described polyamines solution stream and light gas-liquid flow is selected from: tube mixer, venturi mixer, annular space mixing tank, nozzle or micro-mixer; And described mixer outlet be shaped as ellipse, rectangle or rhombus.
16. method according to claim 1 is characterized in that: described smooth gas-liquid flow is injected first step reactor with the flow velocity of 3-30m/s from mixer outlet; Described amine aqueous solution stream injects first step reactor with the flow velocity of 3-30m/s from mixer outlet.
17. method according to claim 16 is characterized in that: described smooth gas-liquid flow is injected first step reactor with the flow velocity of 8-18m/s from mixer outlet; Described amine liquid stream injects first step reactor with the flow velocity of 8-18m/s from mixer outlet.
18. method according to claim 1 is characterized in that: the mol ratio through phosgene and amine in the photochemical liquid after the interface phosgenation reaction is 3:1-4:1.
19. method according to claim 1 is characterized in that: described amine is selected from any in the following compound: 1,4-butanediamine, 1,6-hexanediamine, 1,4-diamines basic ring hexane, 1-amino-3,3,5-trimethylammonium-5-amino methyl hexanaphthene, 4,4 '-dicyclohexyl methyl hydride diamines, triaminononane, isomer proportion are 2 of 80/20-65/35,4-/2,6 tolylene diamine mixtures or pure 2, the 4-tolylene diamine, 4,4 '-diamino-dicyclohexyl methane diamines.
20. method according to claim 1, it is characterized in that: described isocyanic ester is selected from any in the following compound: 1,4-fourth vulcabond, 1, hexamethylene-diisocyanate, 1, the diisocyanate based hexanaphthene of 4-, isophorone diisocyanate, 4,4 '-dicyclohexyl methane diisocyanate, triisocyanate base nonane, tolylene diisocyanate, 4,4 '-diamino-dicyclohexyl methane vulcabond.
21. method according to claim 1 is characterized in that: the liquid stream of the solution stream photoreactive gas of polyamines adopts identical solvent, and this solvent is selected from: one or more in toluene, dimethylbenzene, chlorobenzene, orthodichlorobenzene or the naphthane.
22. method according to claim 21 is characterized in that: described solvent is selected from chlorobenzene or orthodichlorobenzene.
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