CN103910613A - Method for producing trimethyl orthoacetate by utilizing hydrogen chloride (HCl) generated during production of toluene diisocynate (TDI) - Google Patents
Method for producing trimethyl orthoacetate by utilizing hydrogen chloride (HCl) generated during production of toluene diisocynate (TDI) Download PDFInfo
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- CN103910613A CN103910613A CN201410145272.0A CN201410145272A CN103910613A CN 103910613 A CN103910613 A CN 103910613A CN 201410145272 A CN201410145272 A CN 201410145272A CN 103910613 A CN103910613 A CN 103910613A
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- methyl alcohol
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- trimethyl orthoacetate
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- hydrogen chloride
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- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C41/00—Preparation of ethers; Preparation of compounds having groups, groups or groups
- C07C41/60—Preparation of compounds having groups or groups
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J19/00—Chemical, physical or physico-chemical processes in general; Their relevant apparatus
- B01J19/0006—Controlling or regulating processes
- B01J19/002—Avoiding undesirable reactions or side-effects, e.g. avoiding explosions, or improving the yield by suppressing side-reactions
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J19/00—Chemical, physical or physico-chemical processes in general; Their relevant apparatus
- B01J19/02—Apparatus characterised by being constructed of material selected for its chemically-resistant properties
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J19/00—Chemical, physical or physico-chemical processes in general; Their relevant apparatus
- B01J19/18—Stationary reactors having moving elements inside
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J2219/00—Chemical, physical or physico-chemical processes in general; Their relevant apparatus
- B01J2219/00049—Controlling or regulating processes
- B01J2219/00051—Controlling the temperature
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J2219/00—Chemical, physical or physico-chemical processes in general; Their relevant apparatus
- B01J2219/00761—Details of the reactor
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J2219/00—Chemical, physical or physico-chemical processes in general; Their relevant apparatus
- B01J2219/02—Apparatus characterised by their chemically-resistant properties
- B01J2219/0204—Apparatus characterised by their chemically-resistant properties comprising coatings on the surfaces in direct contact with the reactive components
- B01J2219/0213—Apparatus characterised by their chemically-resistant properties comprising coatings on the surfaces in direct contact with the reactive components of enamel
Abstract
The invention discloses a method for producing trimethyl orthoacetate by utilizing hydrogen chloride (HCl) generated during production of toluene diisocynate (TDI). The method comprises the following steps: carrying out pressure boosting on a dried normal-pressure and low-temperature HCl waste gas taken as a byproduct during production of TDI and then feeding methyl alcohol into HCl so as to prepare an alcohol acid; carrying out a salt forming reaction on the alcohol acid and acetonitrile in an inert solvent so as to prepare an ethyleneimine methyl ether hydrochloride; feeding methyl alcohol twice, carrying out an alcoholysis reaction and distilling so as to prepare trimethyl orthoacetate. According to the method, dried normal-pressure and low-temperature HCl generated during the production of TDI is taken a raw material, namely, the recycling of a waste material is realized, so that the cost is lowered; the safety and the environmental friendliness are realized. The alcohol acid is prepared, so that the problems that the metering of HCl is inaccurate and the temperature is difficult to control because a large quantity of heat is released during the salt forming reaction are solved; the solvent with a high boiling point is used, so that the safe and environment-friendly problem that the solvent with a low boiling point is toxic and flammable is solved; the continuous rectification is carried out, so that the problem of long production cycle is solved. The yield of prepared trimethyl orthoacetate can reach 76% to 80%.
Description
Technical field
The present invention relates to technical field of chemistry and chemical engineering, relate in particular to a kind of method of utilizing the hydrogen chloride production trimethyl orthoacetate of producing tolylene diisocyanate.
Background technology
Trimethyl orthoacetate molecular formula: C
5h
12o
3, outward appearance: colourless liquid, fragrance: have special odor, stimulate very much, fragrance remaining time is short, solvability: dissolve in ethanol and ether, stability: meet water decomposition, boiling point: 107-109 ℃.Mainly as the chemical intermediate of producing medicine and agricultural chemicals.For the synthesis of VITMAIN B1, retinol1, the pharmaceutical intermediates such as sulfidin, also can be used for dyestuff and perfume industry.Medicine, family property chemical industry, also can be used for dyestuff and perfume industry.Medicine, chemurgy, oil paint additive.
The HCl gas using in the preparation method of existing trimethyl orthoacetate, is generally to obtain by the vitriol oil and solid sodium chloride reaction, or resolves industrial waste acid-hydrochloric acid, the common water content of HCl gas obtaining is larger, affect product yield, etching apparatus, increases investment.
The low-temperature anhydrous hydrogenchloride of unstripped gas using in the preparation method of existing trimethyl orthoacetate, carry by pipeline, gaseous mass cannot accurate-metering, in order to guarantee that raw material acetonitrile transforms completely, often pass into excessive HCl gas, in the time that next step regulates pH value with liquefied ammonia, will generate more ammonium chloride, affect subsequent disposal.
In the preparation method of existing trimethyl orthoacetate, use normal hexane as inert solvent, normal hexane boiling point is low, when distillation, need to first steam, and then steams product, and energy consumption is larger, and normal hexane is poisonous, inflammable, has larger potential safety hazard.
In the preparation method of existing trimethyl orthoacetate, use jacketed type reactor, cooling performance is very poor, and temperature of reaction is wayward, easily causes overtemperature, and side reaction occurs, and yield is very low.
Summary of the invention
The present invention is to produce TDI(tolylene diisocyanate) by product-normal pressure, low temperature, dry HCl waste gas supercharging after pass into methyl alcohol, make alkyd; In inert solvent, there is salt-forming reaction with acetonitrile, make ethyliminum methyl ether hydrochloride; Pass into two batches of methyl alcohol, alcoholysis reaction occurs, make trimethyl orthoacetate through distillation.
The present invention adopts following technical scheme:
The concrete steps of the method for the hydrogen chloride production trimethyl orthoacetate of utilization production tolylene diisocyanate of the present invention are as follows:
(1) first in reactor, add methyl alcohol and the hydrogen chloride gas of producing tolylene diisocyanate, make alkyd, and then add acetonitrile and inert solvent, the mol ratio of acetonitrile, methyl alcohol, hydrogenchloride is 1:3-3.5:1-1.2, then at-5-30 ℃, react 4-6h, produce white crystals shape ethyliminum methyl ether hydrochloride;
(2) regulate below reactor temperature to 0 ℃, then add the mixing solutions of methyl alcohol and ammonia, regulate pH to 5-6, again add methyl alcohol, add-on is 2 times of acetonitrile molar weight, then heats at 0-45 ℃ and reacts 6-7h;
(3) then the reactant in reactor is carried out to centrifugal and sedimentation, remove ammonium chloride and sodium-chlor;
(4) again the reactant after sedimentation is passed in still kettle, distill and make trimethyl orthoacetate.
In step (1), the hydrogenchloride of producing tolylene diisocyanate is dried and supercharging passing into before reactor.
In step (1), inert solvent is 200# solvent oil.
In step (1), the mol ratio of acetonitrile, methyl alcohol, hydrogenchloride is preferably 1:3:1.1.
In step (1), preferable reaction temperature is 20 ℃.
In step (2), preferably regulate pH to 5.6.
In step (2), preferable reaction temperature is 45 ℃.
In step (2), in the mixing solutions of methyl alcohol and ammonia, the content of amine liquid is 13-14%.
The device that the hydrogen chloride production trimethyl orthoacetate of tolylene diisocyanate is produced in utilization of the present invention is the glassed steel reaction vessels that band stirs, and is provided with two vertical condensers in stirring rake zygomorphy.
The synthetic trimethyl orthoacetate of acetonitrile reacts in two steps.First under solvent exists, pass into dry hydrogen chloride gas by acetonitrile and methyl alcohol, carry out salt-forming reaction, generate ethyliminum methyl ether hydrochloride; Add the methyl alcohol of twice amount of substance to carry out alcoholysis reaction again, make trimethyl orthoacetate, reaction formula is as follows:
Salt-forming reaction reaction equation is as follows:
Alcoholysis reaction reaction equation is as follows:
Positively effect of the present invention is as follows:
The present invention utilizes normal pressure, low temperature, the dry waste gas HCl in production production of toluene diisocyanate process to do raw material, turns waste into wealth, and reduces costs safety and environmental protection.
The present invention has solved the inaccurate and uppity problem of a large amount of exothermic temperatures of salt-forming reaction of HCl metering by preparing alkyd; Dissolve poisonous, inflammable safety and environmental protection problem by using high boiling solvent to solve lower boiling, solved long problem of production cycle by continuous rectification.
It is very poor that the present invention has solved cooling performance by the reactor of built-in vertical condenser and stirring, and temperature of reaction is wayward, easily causes overtemperature, and side reaction occurs, the problem that yield is very low.
The yield of trimethyl orthoacetate prepared by the present invention reaches 76-80%.
Accompanying drawing explanation
Fig. 1 is the process flow sheet that the method for the hydrogen chloride production trimethyl orthoacetate of tolylene diisocyanate is produced in utilization of the present invention.
Fig. 2 is the schematic diagram that the device of the hydrogen chloride production trimethyl orthoacetate of tolylene diisocyanate is produced in utilization of the present invention.
Embodiment
The following examples are to describe in further detail of the present invention.
Embodiment 1
1.1 raw materials for production
Acetonitrile, methyl alcohol, 200# solvent oil, hydrogenchloride (being dried), sodium methylate (methanol solution), liquefied ammonia.
1.2 major equipment
Glassed steel reaction vessels
1.3 production process
1.3.1 prepare alkyd
First in reactor, add methyl alcohol and the hydrogen chloride gas of producing tolylene diisocyanate, make alkyd.
1.3.2 salt-forming reaction
(1) feed intake: the acetonitrile measuring, alkyd, solvent are dropped in reactor;
(2) reaction: (20 ± 2) ℃ insulation reaction 4～6 hours, generate white crystals shape ethyliminum methyl ether hydrochloride;
(3) analyze: sampling detects ethane nitrile content, judges whether complete reaction.
1.3.3 alcoholysis reaction
(1) regulate pH value: cooling, below 0 ℃, passes into alcohol-ammonia solution (ammonia content 13%～14%), makes pH=5.6 ± 0.2;
(2) supplement methyl alcohol: supplement methyl alcohol, make n methyl alcohol: n acetonitrile ≈ 2: 1;
(3) alcoholysis reaction becomes ester: heating, (40 ± 2) ℃ insulation reaction 6～7 hours, detect during this time the content of ester, and while no longer increasing, stopped reaction.
1.3.4 centrifugal and sedimentation
(1) centrifugal: by alcoholysis liquid squeeze in crystallization kettle, carry out centrifugal, separating ammonium chloride;
(2) sedimentation: squeeze into slurry tank and carry out sedimentation, separate sodium-chlor.
1.3.5 distillation
(1) the neutralizer after sedimentation enters still kettle through deep bed filter;
(2) open and stir, heat up, total reflux;
(3) extraction low-boiling-point substance is mainly methyl alcohol;
(4) be warming up to (108 ± 1) ℃, extraction front-end volatiles (being mainly that product and a small amount of low-boiling-point substance are as methyl acetate, methyl alcohol etc.);
(5) extraction product, content >=99%.
Make after reaction product, reaction yield is 80% as calculated.
The improvement of embodiment 2 reactors:
Thermopositive reaction in synthetic for chemical industry, the general mode that adds coiled pipe cooler in still that adopts solves, react for multiphase medium, because stirring problem causes dielectric distribution inhomogeneous, thermopositive reaction is too fast, cause local temperature too high, general facilities (referring to cooling) is caused to operating influence, increase power consumption; Inside reactor subregion causes local temperature too high because mixing effect is poor, can make side reaction increase, and yield reduces.To thermopositive reaction, too high because of local temperature, easily cause bumping and explosion hazard.
Original design still inner condenser is round coil tube type, in the time stirring, easily form water conservancy diversion whirlpool, heterogeneous reaction medium can not fully disperse, cause outside coil condenser the material can not complete reaction, easily form bag slurry phenomenon (the salt crystal generating unreacted acetonitrile is wrapped in) and local superheating reaction and produce sub-ethamine methyl ether hydrochloride decomposed or generate other by products.
According to above deficiency of the prior art, following technical solution is proposed: design one can overcome above-mentioned defect, can improve the vertical cooling reactor of cooling performance.
Coordinate vane type to stir, two vertical (type) condensers are set in reactor, be symmetricly set on the stirring rake both sides of reactor, be fixedly connected with reactor inwall.As shown in Figure 2.
Technical characterictic
(1) still inner condenser adopts vertical.
(2) select modification spraying tetrafluoro, lightweight, resistance to HCl corrosion, widely applicable.
(3) in still, adopt two groups of condensers, increase heat interchanging area.
(4) be convenient to be tightly connected with enamel reaction still.
Desired result
(1) by increasing vertical (type) condenser, make multinomial medium under the effect of stirring, be uniformly distributed in reactor in the time entering reactor, eliminate bag slurry phenomenon.
(2) reactor temperature distributes on average, eliminates local superheating phenomenon, reduces by product.
(3) in the time adding acetonitrile with larger flow, it is stable that reactor temperature keeps, and shortens the production cycle, enhances productivity.
(4) eliminate the phenomenon that material can not react comprehensively outside former coil pipe, reduce and consume, reduce discharge.
(5) improve synthesis yield, reduce production costs.
Test-results
(1) insulation reaction temperature can improve and stablize and is controlled at (20 ± 2) ℃, and salt-forming reaction speed is obviously accelerated, and temperature of reaction curve controlled is steady, and the production cycle shortens.
(2) bag slurry phenomenon basically eliminate: sampling detects ethane nitrile content, unconverted acetonitrile≤1%.
(3) by product ethanamide reduces.
Although illustrated and described embodiments of the invention, for the ordinary skill in the art, be appreciated that without departing from the principles and spirit of the present invention and can carry out multiple variation, modification, replacement and modification to these embodiment, scope of the present invention is limited by claims and equivalent thereof.
Claims (9)
1. a method of utilizing the hydrogen chloride production trimethyl orthoacetate of producing tolylene diisocyanate, is characterized in that: the concrete steps of described method are as follows:
(1) first in reactor, add methyl alcohol and the hydrogen chloride gas of producing tolylene diisocyanate, make alkyd, and then add acetonitrile and inert solvent, the mol ratio of acetonitrile, methyl alcohol, hydrogenchloride is 1:3-3.5:1-1.2, then at-5-30 ℃, react 4-6h, produce white crystals shape ethyliminum methyl ether hydrochloride;
(2) regulate below reactor temperature to 0 ℃, then add the mixing solutions of methyl alcohol and ammonia, regulate pH to 5-6, again add methyl alcohol, add-on is 2 times of acetonitrile molar weight, then heats at 0-45 ℃ and reacts 6-7h;
(3) then the reactant in reactor is carried out to centrifugal and sedimentation, remove ammonium chloride and sodium-chlor;
(4) again the reactant after sedimentation is passed in still kettle, distill and make trimethyl orthoacetate.
2. the method for claim 1, is characterized in that: in step (1), the hydrogenchloride of producing tolylene diisocyanate is dried and supercharging passing into before reactor.
3. the method for claim 1, is characterized in that: in step (1), inert solvent is 200# solvent oil.
4. the method for claim 1, is characterized in that: in step (1), the mol ratio of acetonitrile, methyl alcohol, hydrogenchloride is 1:3:1.1.
5. the method for claim 1, is characterized in that: in step (1), temperature of reaction is 20 ℃.
6. the method for claim 1, is characterized in that: in step (2), regulate pH to 5.6.
7. the method for claim 1, is characterized in that: in step (2), temperature of reaction is 45 ℃.
8. the method for claim 1, is characterized in that: in step (2), in the mixing solutions of methyl alcohol and ammonia, the content of amine liquid is 13-14%.
9. utilize a device for the hydrogen chloride production trimethyl orthoacetate of producing tolylene diisocyanate, this device is the glassed steel reaction vessels that band stirs, and it is characterized in that: be provided with two vertical condensers in stirring rake zygomorphy.
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| CN201410145272.0A CN103910613B (en) | 2014-04-11 | 2014-04-11 | A kind of method utilizing the hydrogen chloride production trimethyl orthoacetate producing tolylene diisocyanate |
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| CN201410145272.0A CN103910613B (en) | 2014-04-11 | 2014-04-11 | A kind of method utilizing the hydrogen chloride production trimethyl orthoacetate producing tolylene diisocyanate |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114181115A (en) * | 2021-12-28 | 2022-03-15 | 山东新和成维生素有限公司 | Salifying system, salifying process and preparation process of trimethyl orthoacetate |
| CN114605234A (en) * | 2020-12-09 | 2022-06-10 | 南通天泽化工有限公司 | Preparation method of trimethyl orthoacetate |
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|---|---|---|---|---|
| JPS52125108A (en) * | 1976-04-14 | 1977-10-20 | Kuraray Co Ltd | Synthesis of 1,1,1-trimethoxyethane |
| JPS5659730A (en) * | 1979-10-19 | 1981-05-23 | Nippon Synthetic Chem Ind Co Ltd:The | Preparation of orthoacetic ester |
| WO2008055904A1 (en) * | 2006-11-07 | 2008-05-15 | Basf Se | Method for producing isocyanates |
| CN101565360A (en) * | 2008-04-21 | 2009-10-28 | 南通天泽化工有限公司 | Trimethyl orthoacetate and synthetic method thereof |
| CN101774948A (en) * | 2010-03-01 | 2010-07-14 | 甘肃银达化工有限公司 | Method for continuously preparing toluene diisocynate |
| CN102060678A (en) * | 2010-12-27 | 2011-05-18 | 江苏优士化学有限公司 | Synthesis process of trimethyl orthoacetate |
| CN202741125U (en) * | 2012-07-24 | 2013-02-20 | 烟台福川化工有限公司 | Vertical type cooling reaction kettle |
-
2014
- 2014-04-11 CN CN201410145272.0A patent/CN103910613B/en active Active
Patent Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS52125108A (en) * | 1976-04-14 | 1977-10-20 | Kuraray Co Ltd | Synthesis of 1,1,1-trimethoxyethane |
| JPS5659730A (en) * | 1979-10-19 | 1981-05-23 | Nippon Synthetic Chem Ind Co Ltd:The | Preparation of orthoacetic ester |
| WO2008055904A1 (en) * | 2006-11-07 | 2008-05-15 | Basf Se | Method for producing isocyanates |
| CN101565360A (en) * | 2008-04-21 | 2009-10-28 | 南通天泽化工有限公司 | Trimethyl orthoacetate and synthetic method thereof |
| CN101774948A (en) * | 2010-03-01 | 2010-07-14 | 甘肃银达化工有限公司 | Method for continuously preparing toluene diisocynate |
| CN102060678A (en) * | 2010-12-27 | 2011-05-18 | 江苏优士化学有限公司 | Synthesis process of trimethyl orthoacetate |
| CN202741125U (en) * | 2012-07-24 | 2013-02-20 | 烟台福川化工有限公司 | Vertical type cooling reaction kettle |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114605234A (en) * | 2020-12-09 | 2022-06-10 | 南通天泽化工有限公司 | Preparation method of trimethyl orthoacetate |
| CN114605234B (en) * | 2020-12-09 | 2023-12-26 | 南通天泽化工有限公司 | Preparation method of trimethyl orthoacetate |
| CN114181115A (en) * | 2021-12-28 | 2022-03-15 | 山东新和成维生素有限公司 | Salifying system, salifying process and preparation process of trimethyl orthoacetate |
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