CN103936623A - Process for preparing toluene diisocyanate (TDI) by using toluenediamine and dimethyl carbonate - Google Patents
Process for preparing toluene diisocyanate (TDI) by using toluenediamine and dimethyl carbonate Download PDFInfo
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Abstract
The invention relates to a process for preparing toluene diisocyanate (TDI) by using toluenediamine and dimethyl carbonate. According to the process, a deactivation catalyst, namely zinc oxide (ZnO), of a reaction, which is used for synthesizing toluene dicarbamate (TDC) through catalyzing toluenediamine and dimethyl carbonate by zinc acetate, is used as a catalyst of a reaction for TDC decomposed TDI preparation, the deactivation catalyst, namely ZnO, of the reaction is not required to be separated from the product TDC and is directly applied to the reaction for TDC decomposition catalyzed TDI preparation, and a TDC decomposed TDI preparation process adopts that decomposition reactors of two stages are in series connection and a fractional condenser is arranged between the decomposition reactors of two stages. According to the process, TDC is synthesized through catalyzing toluenediamine and dimethyl carbonate by zinc acetate, and the deactivation catalyst, namely ZnO, of TDC synthesis is selected as an efficient catalyst for TDC decomposition reaction, so that the catalysis effect is good, and the yield of TDI is high; and the temperature of the TDC decomposition reaction is low, so that the total production cost can be greatly reduced.
Description
Technical field
The present invention is that to take tolylene diamine and methylcarbonate be raw material, first synthetic toluencediamine base methyl-formiate, and then through catalytic decomposition, prepare the technology of tolylene diisocyanate.
Background technology
Tolylene diisocyanate (TDI) is important organic chemical industry's intermediate, is one of important source material of polyurethane industrial.Current industrial TDI produces and adopts phosgenation, but its raw material phosgene severe toxicity and by product HCl easily cause equipment corrosion, therefore the research of non-phosgene synthesis TDI are enjoyed to domestic and international attention always.Wherein with tolylene diamine (TDA), react synthetic toluencediamine base methyl-formiate (TDC), TDC obtain TDI again technique through decomposing with methylcarbonate (DMC) and have much industrialization potentiality.
Existing manyly about amine and organic carbonate synthesis of carbamates, carbamate, through decomposition, prepare again the bibliographical information of isocyanic ester.
Amine reacts synthesis of carbamates aspect: patent US4268683, US4268684 and WO99/47493 etc. all to be used catalyzer to carry out organic carbonate to react synthesis of carbamates with amine with organic carbonate, but does not relate to the recycling of catalyzer.Patent ZL03156418.6 prepares toluencediamine base methyl-formiate with zinc acetate catalysis tolylene diamine and dimethyl carbonate, and the renovation process of catalyzer is provided.Patent ZL200710056664.X catalyzes and synthesizes toluencediamine base methyl-formiate with zinc acetate, is inorganic materials nano zine oxide by the catalyst development of inactivation simultaneously.
Carbamate decomposes and prepares isocyanic ester aspect: patent EP0672653A1 is that isocyanic ester is prepared in decomposition about carbamate, and the catalyzer of employing is an alkali metal salt of organic sulfonic acid or organic sulfonic acid, and decomposition temperature is 150～350 ℃.Zhao Qian [Master's thesis: Hebei University of Technology, 2002.3] be take zinc oxide during as catalyzer, decomposes toluencediamine base methyl-formiates prepare tolylene diisocyanate at 260 ℃, adopts chemistry titration quantitative analysis, and the total recovery that obtains isocyanic ester is 80.61%.
In addition, patent EP0323514A1 has described take diamines and methylcarbonate and prepares the complete procedure of vulcabond as raw material: first under basic catalyst effect, diamines and dimethyl carbonate are prepared carbamate, and product obtains carbamate after phosphoric acid neutralization, benzene and/or washing, distillation; Then at Mn, Mo, W, under the katalysis of the metals such as Zn or Be or its compound, carbamate decomposes and obtains product isocyanic ester, decomposition temperature 150-300 ℃.
Patent US20030162995A1 provides take aromatic amine and organic carbonate and prepares the integrated approach of aromatic isocyanates as raw material: first under catalyzer exists, aromatic amine reacts synthesis of carbamates with organic carbonate, then remove used catalyst, then to make carbamate thermolysis be isocyanic ester.The temperature range of first step decomposition reactor is 230-380 ℃, and the temperature of second stage decomposition reactor is 300-600 ℃.
As fully visible:
(1) for amine, react synthesis of carbamates process with organic carbonate: after having reacted in document, need carbamate and catalyst separating, then just can carry out next step decomposition reaction.Must there is catalyst separating step, and not consider the comprehensive reasonable utilization of catalyzer in synthesizing isocyanate process.
(2) for carbamate, decompose and prepare isocyanic ester process: most literature is to carry out under catalyst action, and the catalyzer adopting is all irrelevant with carboxylamine catalyst for ester synthesis, decomposition temperature is high; Although there is decomposition reaction in document not adopt catalyzer, but need under high-temperature, carry out very much, the temperature of first step reactor has reached 230-380 ℃, the decomposition temperature of second stage reactor reaches 300-600 ℃, easily there is side reaction in high temperature of reaction so, cause product yield low, and can greatly increase equipment cost and production cost.
The present invention has overcome the deficiency of previous method, has optimized TDI synthetic technology.The present invention is directly used in catalysis TDC by the decaying catalyst zinc oxide of synthetic TDC process and decomposes preparation TDI process, inactivation zinc oxide is efficiently recycled, again for TDC decomposition reaction provides effective catalyst; Can save the separating step of synthetic TDC and decaying catalyst zinc oxide, whole TDI synthetic operation is simplified, be conducive to suitability for industrialized production simultaneously; TDC decomposes preparation TDI process and adopts two-stage decomposition reactor serial operation, between two-stage decomposition reactor, is provided with partial condenser, has both reduced decomposition reaction temperature, avoids again side reaction to occur, and effectively improves product yield.
Have not yet to see about amine is reacted to the decaying catalyst of synthesis of carbamates with organic carbonate and be directly used in the research report that isocyanate reaction is prepared in the decomposition of catalytic amino manthanoate, also about carbamate, do not decompose the process introduction that is provided with partial condenser between the decomposition reactor of preparing the operation of isocyanic ester process two-stage series connection.
Summary of the invention
Technical problem to be solved by this invention is: the new technology of the preparation TDI that provide that a kind of technique is simple, catalyzer efficiently recycles, reaction conditions is gentle, avoid high-temperature operation, TDI yield is high, cost is low.Its core is: the decaying catalyst zinc oxide that the synthetic TDC of zinc acetate catalysis tolylene diamine and methylcarbonate is reacted decomposes the catalyzer of preparation TDI reaction as TDC, the decaying catalyst ZnO of this reaction does not need separated with product TDC, but be directly used in catalysis TDC, decompose preparation TDI reaction, TDC decomposes preparation TDI process and adopts two-stage decomposition reactor serial operation, and is provided with partial condenser between two-stage decomposition reactor.
The present invention solves this technical problem adopted technical scheme:
Utilize tolylene diamine and methylcarbonate to prepare a technique for tolylene diisocyanate, comprise the following steps:
1) tolylene diamine and methylcarbonate are that raw material, zinc acetate are the synthetic TDC of catalyzer
First in reactor, add successively tolylene diamine, zinc acetate and methylcarbonate, its mol ratio is tolylene diamine: zinc acetate: methylcarbonate=1: 0.05～0.4: 18～30, and sealed reactor then, under agitation condition, being heated to temperature is 120～180 ℃, reacts 3～8 hours; After reaction finishes, cooling, discharging, feed liquid is gone still kettle, 30～60 ℃, 5～30kPa underpressure distillation, obtains the mixture of solid product TDC and decaying catalyst ZnO;
Gas phase to the first condenser that underpressure distillation goes out, obtains the liquid mixture of methylcarbonate, methyl alcohol and methyl acetate after condensation;
2) TDC catalytic decomposition is prepared TDI
First thermal barrier is added respectively in first step decomposition reactor and second stage decomposition reactor; The TDC that upper step is obtained and the mixture of ZnO, in dissolving tank dissolution with solvents, then add first step decomposition reactor, then get TDC that step obtains and the mixture of ZnO, obtain ZnO after separation, are added second stage decomposition reactor; In first step decomposition reactor, 170～260 ℃, under system pressure 5～25kPa condition, react, the gas-phase product of first step decomposition reactor is through the first fractional column, enter the first partial condenser, at 15～35 ℃, obtain intermediate product toluene monoisocyanates (TMI) liquid, TMI is added to the further decomposition reaction of second stage decomposition reactor, and uncooled gas phase TDI, methyl alcohol remove the second partial condenser; Decomposition reaction actuator temperature in the second stage is, under 180～260 ℃, system pressure 5～25kPa condition, to carry out decomposition reaction; The gas-phase product of second stage decomposition reactor, after after-fractionating post, enters the second partial condenser equally; The condensation at 15～35 ℃ of the second partial condenser, obtains object product TDI; By-product carbinol obtains methyl alcohol through the condensation at-5～15 ℃ of the second condenser;
The same solvent of material that described thermal barrier adopts; Wherein, in two-stage decomposition reactor, ZnO concentration range is equal to or is greater than 8.0 * 10
-4g/mL thermal barrier.
Described thermal barrier is alkane, aromatic hydrocarbon, naphthenic hydrocarbon, ether, ester, amine or sulfone.
Described thermal barrier is preferably dimethyl phthalate, dioctyl phthalate (DOP), dibutyl phthalate, whiteruss, dioctyl sebacate, butyl (tetra) titanate, tetramethylene sulfone or naphthenic oil.
In the middle first step decomposition reactor of described step (2), the feed way of TDC and ZnO is continuous charging or intermittently reinforced.
When in the middle first step decomposition reactor of described step (2), the feed way of TDC and ZnO fed in raw material for intermittence, the first step decomposition reactor reaction times is 0.8-2.0 hour, the reaction times of second stage decomposition reactor starts timing when the first partial condenser flows into this reactor with material, the reaction times is 0.8-2.0 hour.
In described step (1), the tolylene diamine adding is 2,4-tolylene diamine, 2,6-tolylene diamine or their blend.
In described step (1), the tolylene diamine adding is 2,4-tolylene diamine, 2, the blend of 6-tolylene diamine, and the mass ratio of its component is 2,4-tolylene diamine: 2,6-tolylene diamine=65～80: 20～35.
In two-stage reactor, ZnO concentration range is preferably all 8.0 * 10
-4～4.0 * 10
-2between g/mL thermal barrier.
Described step 1) tolylene diamine and methylcarbonate are that raw material, zinc acetate are in the synthetic TDC of catalyzer, while reacting at 120～180 ℃, react for isothermal reaction or two sections of temperature reactions; When being two sections of temperature reactions, react 1～3 hour at 120～140 ℃, be then warming up at 140～180 ℃ and react again 2～5 hours.
The invention has the beneficial effects as follows: the methylcarbonate legal system that the preparation method of TDI of the present invention is that technique is simple, reaction conditions is gentle, catalyzer efficiently utilizes, avoid high-temperature operation, TDI yield is high, production cost is low is for the new technology of TDI.More outstanding substantive distinguishing features is, zinc acetate catalysis tolylene diamine and methylcarbonate prepared to the decaying catalyst ZnO that TDC reacts and for catalysis TDC, decompose preparation TDI process; Save the separating step of decaying catalyst and product TDC; TDC decomposes preparation TDI process and adopts two-stage decomposition reactor serial operation, and is provided with partial condenser between two-stage decomposition reactor, can be under gentle TDC decomposition temperature, obtain the TDI of high yield.
Above-mentioned beneficial effect is embodied in:
(1) the decaying catalyst ZnO of synthetic TDC is as the effective catalyst of TDC decomposition reaction: excellent catalytic effect, TDI yield is high.Products therefrom yield is high more a lot of than take the yield that outsourcing zinc oxide obtains during as catalyzer in background technology.Save the expense of TDC decomposition course for catalyzer, reduced the production cost of TDI.
(2) the efficient recycling of decaying catalyst ZnO: tolylene diamine and methylcarbonate are prepared to the decaying catalyst ZnO that TDC reacts and decompose the catalyzer of preparation TDI as TDC, decaying catalyst ZnO is efficiently recycled, avoided the discarded waste causing of decaying catalyst and the detrimentally affect that environment is caused.
(3) save operation steps: the decaying catalyst ZnO of synthetic TDC reaction decomposes preparation TDI reaction for catalysis TDC, can save the sepn process of TDC and decaying catalyst ZnO, save operation steps, reduce and take tolylene diamine and methylcarbonate and prepare the production cost of TDI as raw material.
(4) reduce decomposition reaction temperature, improve TDI yield: TDC and decompose preparation TDI process employing two-stage decomposition reactor serial operation, and be provided with partial condenser between two-stage decomposition reactor.While having avoided only adopting A reactor, if at low-temp reaction, can completely not decompose and cause TDI yield low because of intermediate product; And if employing pyroreaction can cause the shortcoming that TDI yield is low because of high temperature polymerization side reaction again; Also having avoided not establishing partial condenser between two decomposition reactors can cause TDI to repeat to enter the shortcoming that reactor causes polymerization side reactions.The present invention can, under gentle decomposition temperature, obtain the TDI of high yield.
(5) reduce equipment cost and running cost: TDC decomposition reaction temperature of the present invention is low, can reduce equipment cost, also can save the cold medium consumption of reaction later stage condenser, reduce the cost recovery of by-product carbinol, total cost of production is reduced.
Accompanying drawing explanation
Accompanying drawing 1 is tolylene diamine (TDA) and synthetic tolylene diisocyanate (TDI) the process schematic diagram of methylcarbonate (DMC), wherein, and 1-reactor, 2-underpressure distillation still, 3-the first condenser, 4-dissolving tank, 5-first step decomposition reactor, 6-second stage decomposition reactor, 7-the first fractional column, 8-after-fractionating post, 9-the first partial condenser, 10-the second partial condenser, 11-the second condenser
Embodiment:
By the following example, the present invention is described, but the invention is not restricted to the following example.
Tolylene diisocyanate synthesizer of the present invention as shown in Figure 1.
Toluencediamine base methyl-formiate is synthetic: first tolylene diamine, methylcarbonate and catalyzer zinc acetate are added to reactor 1, its mol ratio is tolylene diamine: zinc acetate: methylcarbonate=1: 0.05～0.4: 18～30, then sealed reactor, under agitation condition, being heated to temperature is 120～180 ℃, reacts 3～8 hours.This building-up reactions can be carried out by constant temperature, also can carry out by alternating temperature.The pressure of reactor is system autogenous pressure, does not need other adjusting.After having reacted, material cooling, discharging, feed liquid is to underpressure distillation still 2,30～60 ℃, 5～30kPa underpressure distillation, obtain the mixture of solid product toluencediamine base methyl-formiate and decaying catalyst zinc oxide, gas phase, to condenser 3, obtains the liquid mixture of methylcarbonate, methyl alcohol and methyl acetate after condensation.
Toluencediamine base methyl-formiate decomposes: first thermal barrier is added respectively to first step decomposition reactor 5 and second stage decomposition reactor 6, the TDC that upper step is obtained and the mixture of ZnO add first step decomposition reactor 5 after dissolving tank 4 dissolves, get again TDC that step obtains and the mixture of ZnO, after separation, obtain ZnO, added second stage decomposition reactor 6; In first step decomposition reactor 5,170～260 ℃, under system pressure 5～25kPa condition, react, the gas-phase product of first step decomposition reactor 5 is through fractional column 7, enter partial condenser 9, at 15～35 ℃, obtain intermediate product toluene monoisocyanates (TMI), TMI is added to the further decomposition reaction of second stage decomposition reactor 6, and uncooled gas phase TDI, methyl alcohol remove partial condenser 10; Decomposition reactor 6 temperature in the second stage are, under 180～260 ℃, system pressure 5～25kPa condition, to carry out decomposition reaction; The gas-phase product of second stage decomposition reactor 6, after fractional column 8, enters partial condenser 10 equally; Partial condenser 10 condensation at 15～35 ℃, obtains object product TDI; By-product carbinol obtains methyl alcohol through condenser 11 condensation at-5～15 ℃.
In two-stage decomposition reactor, ZnO concentration range is equal to or is greater than 8.0 * 10
-4g/mL thermal barrier; In two-stage decomposition reactor, ZnO concentration range is preferably all 8.0 * 10
-4～4.0 * 10
-2between g/mL thermal barrier.
Embodiment 1:
(1) in reactor 1, add successively 5g2,4-tolylene diamine, 97mL methylcarbonate, 0.82g zinc acetate, then sealed reactor.Under agitation condition, being heated to temperature is 140 ℃, reacts 3 hours; Be warming up to 170 ℃ again, and start meter from heating up, maintain reaction 3 hours, reaction finishes.Reacted feed liquid cooling, discharging, to underpressure distillation still 2 at 30 ℃, 5kP
aunderpressure distillation under condition, obtains the mixture 10.1g of solid product toluencediamine base methyl-formiate and zinc oxide, adopts high performance liquid chromatography to analyze product, and toluencediamine base methyl-formiate yield is 99.2%.
The gas phase that underpressure distillation goes out, to condenser 3, obtains the liquid mixture of methylcarbonate, methyl alcohol and methyl acetate after condensation, by traditional method, isolate methylcarbonate, and methylcarbonate loops back TDC building-up process (following examples are same);
(2) in two-stage decomposition reactor 5 and 6, add 50mL dioctyl phthalate (DOP) respectively, logical nitrogen, adds 0.4g zinc oxide (TDC that upper step obtains and the mixture of ZnO obtain ZnO after separation) in second stage decomposition reactor 6 simultaneously.Reacting system pressure is adjusted to 8kPa, regulating the cold medium temperature of partial condenser 9 is 15 ℃, the cold medium temperature that regulates partial condenser 10 is that 20 ℃, the cold medium temperature of condenser 11 are-5 ℃, and first step decomposition reactor 5 temperature are 260 ℃, and reactor 6 temperature in the second stage are 180 ℃.The TDC obtaining in 1.4g above-mentioned steps (1) and the mixture of zinc oxide are dissolved in dioctyl phthalate (DOP), and it is at the uniform velocity added to first step decomposition reactor 5, charging reaction time remaining 1.5h, after reaction finishes, the TDI amount that the decomposition reaction of metering two-stage is collected, adopts ethanol derivatization method to carry out efficient liquid phase chromatographic analysis to product, to join the TDC of decomposition reactor 5, TDI yield is that 90.6%, TDI and TMI total recovery are 99.8%.
The cooling medium that in the present embodiment, condenser uses is industrial spirit (following examples are same).
Embodiment 2
Step (1) is with embodiment 1.
(2) in two-stage decomposition reactor 5 and 6, add 50mL dibutyl phthalate respectively, logical nitrogen, adds 0.2g zinc oxide (TDC that upper step obtains and the mixture of ZnO obtain ZnO after separation) in second stage decomposition reactor 6 simultaneously.Reacting system pressure is adjusted to 10kPa, regulating the cold medium temperature of partial condenser 9 is 15 ℃, and regulating the cold medium temperature of partial condenser 10 is 20 ℃, and the cold medium temperature of condenser 11 is 0 ℃, first step decomposition reaction actuator temperature is 220 ℃, and decomposition reaction actuator temperature in the second stage is 240 ℃.The TDC obtaining in 1.4g step (1) and the mixture of zinc oxide are dissolved in appropriate dibutyl phthalate, and it is at the uniform velocity added to first step decomposition reactor, charging reaction time remaining 1.8h, after reaction finishes, the TDI amount that the decomposition reaction of metering two-stage is collected, adopts ethanol derivatization method to carry out efficient liquid phase chromatographic analysis to product, to join the TDC of decomposition reactor 5, TDI yield is that 95.1%, TDI and TMI total recovery are 99.9%.
Embodiment 3:
(1) in reactor 1, add successively 5g2,6-tolylene diamine, 104mL methylcarbonate, 0.38g zinc acetate, then sealed reactor.Under agitation condition, being heated to temperature is 120 ℃, reacts 1 hour; Be warming up to 180 ℃ again, and start meter from heating up, maintain reaction 2 hours, reaction finishes.Cooling, discharging, feed liquid underpressure distillation under 40 ℃, 15kPa condition, obtains solid product Toluene-2,4-diisocyanate, the mixture 9.71g of 4-diamino-methyl formate and zinc oxide, adopt high performance liquid chromatography to analyze product, toluencediamine base methyl-formiate yield is 95.0%.
(2) in two-stage decomposition reactor 5 and 6, add 50mL naphthenic oil respectively, logical nitrogen, adds 2g zinc oxide (TDC that upper step obtains and the mixture of ZnO obtain ZnO after separation) in the decomposition reactor of the second stage simultaneously.Reacting system pressure is adjusted to 15kPa, regulating the cold medium temperature of partial condenser 9 is 20 ℃, and regulating the cold medium temperature of partial condenser 10 is 25 ℃, and the cold medium temperature of condenser 11 is 10 ℃, first step decomposition reaction actuator temperature is 200 ℃, and decomposition reaction actuator temperature in the second stage is 230 ℃.The TDC obtaining in 2.8g above-mentioned steps (1) and the mixture of zinc oxide are dissolved in appropriate naphthenic oil, and it is at the uniform velocity added to first step decomposition reactor, charging reaction time remaining 1.4h, after reaction finishes, the TDI amount that the decomposition reaction of metering two-stage is collected, adopts ethanol derivatization method to carry out efficient liquid phase chromatographic analysis to product, to join the TDC of decomposition reactor, TDI yield is that 85.8%, TDI and TMI total recovery are 99.8%.
Embodiment 4:
(1) in reactor 1, adding successively 5g mass ratio is 2,4-tolylene diamine: 2,6-tolylene diamine=80: 20 mixture, 62mL methylcarbonate, 1.05g zinc acetate, then sealed reactor.Under agitation condition, being heated to temperature is 130 ℃, reacts 2 hours; Be warming up to 160 ℃ again, and start meter from heating up, maintain reaction 5 hours, reaction finishes.Cooling, discharging, feed liquid underpressure distillation under 50 ℃, 20kPa condition, obtains the mixture 9.9g of solid product toluencediamine base methyl-formiate and zinc oxide, and employing high performance liquid chromatography is analyzed product, and toluencediamine base methyl-formiate yield is 94.2%.
(2) in two-stage decomposition reactor 5 and 6, add 50mL butyl (tetra) titanate respectively, logical nitrogen, adds 0.3g zinc oxide (TDC that upper step obtains and the mixture of ZnO obtain ZnO after separation) in the decomposition reactor of the second stage simultaneously.Reacting system pressure is adjusted to 5kPa, regulates the cold medium temperature of partial condenser 9 and 10 to be 15 ℃, regulating the cold medium temperature of condenser 11 is-5 ℃, and first step decomposition reaction actuator temperature is 170 ℃, and decomposition reaction actuator temperature in the second stage is 260 ℃.The TDC obtaining in 1.4g above-mentioned steps (1) and the mixture of zinc oxide are dissolved in appropriate butyl (tetra) titanate, and it is at the uniform velocity added to first step decomposition reactor, charging reaction time remaining 1.2h, after reaction finishes, the TDI amount that the decomposition reaction of metering two-stage is collected, adopts ethanol derivatization method to carry out efficient liquid phase chromatographic analysis to product, to join the TDC of decomposition reactor, TDI yield is that 85.4%, TDI and TMI total recovery are 99.7%.
Embodiment 5:
(1) in reactor 1, add successively 5g2,4-tolylene diamine benzene, 97mL methylcarbonate, 3.01g zinc acetate, then sealed reactor.Under agitation condition, being heated to temperature is 160 ℃, reacts 8 hours, and reaction finishes.Cooling, discharging, feed liquid underpressure distillation under 60 ℃, 30kPa condition, obtains the mixture 11.1g of solid product toluencediamine base methyl-formiate and zinc oxide, and employing high performance liquid chromatography is analyzed product, and toluencediamine base methyl-formiate yield is 97.3%.
(2) in two-stage decomposition reactor, add 50mL dimethyl phthalate respectively, logical nitrogen, adds 0.04g zinc oxide (TDC that upper step obtains and the mixture of ZnO obtain ZnO after separation) in the decomposition reactor of the second stage simultaneously.Reacting system pressure is adjusted to 25kPa, regulates the cold medium temperature of partial condenser 9 and 10 to be 35 ℃, regulating the cold medium temperature of condenser 11 is 15 ℃, and first step decomposition reaction actuator temperature is 230 ℃, and decomposition reaction actuator temperature in the second stage is 250 ℃.The TDC that in 1.4g above-mentioned steps (1), reaction obtains and the mixture of zinc oxide are dissolved in appropriate dimethyl phthalate, and it is at the uniform velocity added to first step decomposition reactor, charging reaction time remaining 2h, after reaction finishes, the TDI amount that the decomposition reaction of metering two-stage is collected, adopts ethanol derivatization method to carry out efficient liquid phase chromatographic analysis to product, to join the TDC of decomposition reactor, TDI yield is that 82.3%, TDI and TMI total recovery are 95.5%.
Embodiment 6:
Step (1) is with embodiment 5.
(2) adopt in embodiment 1 step (2) and use the rear thermal barrier dioctyl phthalate (DOP) reclaiming as the thermal barrier of the present embodiment two-stage decomposition reactor; Adopt second stage decomposition reactor 6 in embodiment 1 step (2) to use the rear zinc oxide reclaiming as the catalyzer of the present embodiment second stage decomposition reactor 6.
In two-stage decomposition reactor, add 50mL dioctyl phthalate (DOP) respectively, logical nitrogen, adds 0.3g zinc oxide in the decomposition reactor of the second stage simultaneously.Reacting system pressure is adjusted to 10kPa, regulating the cold medium temperature of partial condenser 9 is 25 ℃, and regulating the cold medium temperature of partial condenser 10 is 30 ℃, and the cold medium temperature of condenser 11 is 15 ℃, first step decomposition reaction actuator temperature is 190 ℃, and decomposition reaction actuator temperature in the second stage is 260 ℃.The TDC that in 1.4g step (1), reaction obtains and the mixture of zinc oxide are dissolved in appropriate dioctyl phthalate (DOP), and divided equally three times and added first step decomposition reactor, reaction times 0.8h, after reaction finishes, the TDI amount that the decomposition reaction of metering two-stage is collected, adopts ethanol derivatization method to carry out efficient liquid phase chromatographic analysis to product, to join the TDC of decomposition reactor, TDI yield is that 81.2%, TDI and TMI total recovery are 92.6%.
Claims (8)
1. utilize tolylene diamine and methylcarbonate to prepare a technique for tolylene diisocyanate, it is characterized by and comprise the following steps:
1) tolylene diamine and methylcarbonate are that raw material, zinc acetate are the synthetic toluencediamine base methyl-formiate (TDC) of catalyzer
First in reactor, add successively tolylene diamine, zinc acetate and methylcarbonate, its mol ratio is tolylene diamine: zinc acetate: methylcarbonate=1: 0.05～0.4: 18～30, and sealed reactor then, under agitation condition, being heated to temperature is 120～180 ℃, reacts 3～8 hours; After reaction finishes, cooling, discharging, feed liquid is gone still kettle, 30～60 ℃, 5～30kPa underpressure distillation, obtains the mixture of solid product TDC and decaying catalyst ZnO;
Gas phase to the first condenser that underpressure distillation goes out, obtains the liquid mixture of methylcarbonate, methyl alcohol and methyl acetate after condensation;
2) TDC catalytic decomposition is prepared tolylene diisocyanate (TDI)
First thermal barrier is added respectively in first step decomposition reactor and second stage decomposition reactor; The TDC that upper step is obtained and the mixture of ZnO, in dissolving tank dissolution with solvents, then add first step decomposition reactor, then get TDC that step obtains and the mixture of ZnO, obtain ZnO after separation, are added second stage decomposition reactor; In first step decomposition reactor, 170～260 ℃, under system pressure 5～25kPa condition, react, the gas-phase product of first step decomposition reactor is through the first fractional column, enter the first partial condenser, at 15～35 ℃, obtain intermediate product toluene monoisocyanates (TMI), TMI is added to the further decomposition reaction of second stage decomposition reactor, and uncooled gas phase TDI, methyl alcohol remove the second partial condenser; Decomposition reaction actuator temperature in the second stage is, under 180～260 ℃, system pressure 5～25kPa condition, to carry out decomposition reaction; The gas-phase product of second stage decomposition reactor, after after-fractionating post, enters the second partial condenser equally; The condensation at 15～35 ℃ of the second partial condenser, obtains object product TDI; By-product carbinol obtains methyl alcohol through the condensation at-5～15 ℃ of the second condenser;
The same solvent of material that described thermal barrier adopts; Wherein, in two-stage decomposition reactor, ZnO concentration range is equal to or is greater than 8.0 * 10
-4g/mL thermal barrier;
Described thermal barrier is alkane, aromatic hydrocarbon, naphthenic hydrocarbon, ether, ester, amine or sulfone.
2. the technique of utilizing tolylene diamine and methylcarbonate to prepare tolylene diisocyanate as claimed in claim 1, is characterized by described thermal barrier and is preferably dimethyl phthalate, dioctyl phthalate (DOP), dibutyl phthalate, whiteruss, dioctyl sebacate, butyl (tetra) titanate, tetramethylene sulfone or naphthenic oil.
3. the technique of utilizing tolylene diamine and methylcarbonate to prepare tolylene diisocyanate as claimed in claim 1, is characterized by described step (2) TDC in first step decomposition reactor and is continuous charging or intermittently feeds in raw material with the feed way of ZnO.
4. the technique of utilizing tolylene diamine and methylcarbonate to prepare tolylene diisocyanate as claimed in claim 3, when in the middle first step decomposition reactor of step (2) described in it is characterized by, the feed way of TDC and ZnO fed in raw material for intermittence, the first step decomposition reactor reaction times is 0.8-2.0 hour, the reaction times of second stage decomposition reactor starts timing when the first partial condenser flows into this reactor with material, the reaction times is 0.8-2.0 hour.
5. the technique of utilizing tolylene diamine and methylcarbonate to prepare tolylene diisocyanate as claimed in claim 1, is characterized by described step (1), and the tolylene diamine adding is 2,4-tolylene diamine, 2,6-tolylene diamine or their blend.
6. the technique of utilizing tolylene diamine and methylcarbonate to prepare tolylene diisocyanate as claimed in claim 5, it is characterized by described step (1), the tolylene diamine adding is 2,4-tolylene diamine, 2, the blend of 6-tolylene diamine, the mass ratio of its component is 2,4-tolylene diamine: 2,6-tolylene diamine=65～80: 20～35.
7. the technique of utilizing tolylene diamine and methylcarbonate to prepare tolylene diisocyanate as claimed in claim 1, is characterized by ZnO concentration range in two-stage reactor and is preferably all 8.0 * 10
-4～4.0 * 10
-2between g/mL thermal barrier.
8. the technique of utilizing tolylene diamine and methylcarbonate to prepare tolylene diisocyanate as claimed in claim 1, it is characterized by described step 1) tolylene diamine and methylcarbonate is that raw material, zinc acetate are in the synthetic TDC of catalyzer, while reacting at 120～180 ℃, react for isothermal reaction or two sections of temperature reactions; When being two sections of temperature reactions, react 1～3 hour at 120～140 ℃, be then warming up at 140～180 ℃ and react again 2～5 hours.
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| CN105153035A (en) * | 2015-09-07 | 2015-12-16 | 江苏泰仓农化有限公司 | Preparation method of toluene diisocyanate bipolymer |
| CN107488132A (en) * | 2017-09-25 | 2017-12-19 | 陕西煤业化工技术开发中心有限责任公司 | A kind of method that heterogeneous catalysis pyrolysis prepares toluene di-isocyanate(TDI) |
| CN110105248A (en) * | 2019-05-31 | 2019-08-09 | 上海应用技术大学 | A kind of preparation method of toluene di-isocyanate(TDI) |
| CN110256296A (en) * | 2019-05-20 | 2019-09-20 | 江苏蓝丰生物化工股份有限公司 | The synthetic method of 1,5- naphthalene diisocyanate |
| CN110981753A (en) * | 2019-12-19 | 2020-04-10 | 山东华阳农药化工集团有限公司 | Preparation of diphenyl ethane diisocyanate by dimethyl carbonate method and application thereof |
| CN115073324A (en) * | 2022-07-05 | 2022-09-20 | 中国科学院过程工程研究所 | Method for preparing pentanedicarbamate by homogeneous catalysis |
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Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105153035A (en) * | 2015-09-07 | 2015-12-16 | 江苏泰仓农化有限公司 | Preparation method of toluene diisocyanate bipolymer |
| CN107488132A (en) * | 2017-09-25 | 2017-12-19 | 陕西煤业化工技术开发中心有限责任公司 | A kind of method that heterogeneous catalysis pyrolysis prepares toluene di-isocyanate(TDI) |
| CN110256296A (en) * | 2019-05-20 | 2019-09-20 | 江苏蓝丰生物化工股份有限公司 | The synthetic method of 1,5- naphthalene diisocyanate |
| CN110105248A (en) * | 2019-05-31 | 2019-08-09 | 上海应用技术大学 | A kind of preparation method of toluene di-isocyanate(TDI) |
| CN110105248B (en) * | 2019-05-31 | 2021-07-20 | 上海应用技术大学 | Preparation method of toluene diisocyanate |
| CN110981753A (en) * | 2019-12-19 | 2020-04-10 | 山东华阳农药化工集团有限公司 | Preparation of diphenyl ethane diisocyanate by dimethyl carbonate method and application thereof |
| CN115073324A (en) * | 2022-07-05 | 2022-09-20 | 中国科学院过程工程研究所 | Method for preparing pentanedicarbamate by homogeneous catalysis |
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