CN104387295B - Preparation method of methyl isocyanate - Google Patents
Preparation method of methyl isocyanate Download PDFInfo
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- CN104387295B CN104387295B CN201410767754.XA CN201410767754A CN104387295B CN 104387295 B CN104387295 B CN 104387295B CN 201410767754 A CN201410767754 A CN 201410767754A CN 104387295 B CN104387295 B CN 104387295B
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Abstract
The invention provides a preparation method of methyl isocyanate. A reaction product synthesized at the high temperature is directly fed into a first organic solvent for treatment at the temperature of 200-300 DEG C, effective separation of the methyl isocyanate and hydrogen chloride is realized, the fact that the methyl isocyanate reacts with the hydrogen chloride to produce methyl carbamyl chloride is avoided, the once-through yield of the methyl isocyanate is increased, repeated heating and condensation are not required, energy consumption and production of by-products are reduced, meanwhile, multiple decomposition reactors are not required and the number of condensers is decreased in the aspect of devices, and the investment cost and the production cost are greatly reduced.
Description
Technical field
The present invention relates to organic synthesis field, more particularly, to a kind of preparation method of methyl isocyanate.
Background technology
Methyl isocyanate is a kind of important pesticide intermediate, is mainly used in synthesis of carbamates class pesticide, such as: gram
Budweiser, Methomyl, meta-tolyl-N-methylcarbamate (MTMC), Mobucin (isoprocarb), Bassa (Ba Sha), carbaryl, arprocarb, well peace prestige, sulfur double go out many
Prestige, Benfuracard micro and tebuthiuron etc..
Report currently, with respect to the preparation method of methyl isocyanate is more, such as DE Published Patent 2422211,
2503270, United States Patent (USP) 8969889, the clear 42-8911 of Japan Patent, clear 46-24123, Chinese patent cn86100286,
Cn102976976a etc.；The preparation method of methyl isocyanate disclosed in above-mentioned patent is all with phosgene with monomethyl amine for raw material first
Prepare methyl amido formyl chloride, then in the presence of atent solvent (as carbon tetrachloride, chloroform, toluene etc.), methyl
Carbamyl chloride carries out decomposing, rectification produces methyl isocyanate, generates methyl isocyanide acid because methyl amido formyl chloride decomposes
For reversible reaction so that once through yield is low, molar percentage is 60% about for the reaction of ester and hydrogen chloride, so, existing first
In the preparation method of based isocyanate, whole preparation process needs heating for multiple times and condensation, and preparation flow is longer, on the one hand makes
Byproduct of reaction trimerization methyl isocyanate is more, and then the yield of methyl isocyanate is reduced, and the three wastes increase；The opposing party
Face, due to methyl amido formyl chloride decomposition prepare methyl isocyanate yield low, multiple stage decomposition reactor need to be configured, therefore lead
Cause equipment investment big.
Content of the invention
In view of this, the technical problem to be solved is to provide a kind of preparation method of methyl isocyanate,
This preparation method flow process is short, methyl isocyanate high income, and low production cost.
The invention provides a kind of preparation method of methyl isocyanate, comprising:
1) phosgene and monomethyl amine are reacted at 300～400 DEG C, the product obtaining is maintained at 200～300 DEG C and the
One organic solvent mixing, obtains the solution containing methyl isocyanate and the first gaseous substance；
2) organic solvent in the solution containing methyl isocyanate is removed, obtain methyl isocyanate.
Preferably, described phosgene and the mol ratio of described monomethyl amine are (1.0～1.2): 1.
Preferably, described first organic solvent is one of benzene, toluene, chlorobenzene, dichloromethane, chloroform and carbon tetrachloride
Or it is several.
Preferably, in the described solution containing methyl isocyanate methyl isocyanate and the first organic solvent mol ratio
For 1:(4～10).
Preferably, described step 1) after step 2) before also include: the solution containing methyl isocyanate is taken off
Process except phosgene and hydrogen chloride.
Preferably, the temperature of described removing phosgene and hydrochlorination is 10～130 DEG C.
Preferably, described step 1) also include mixing described first gaseous substance with the second organic solvent afterwards, obtain
Solution containing trace methyl isocyanates and the second gaseous substance.
Preferably, described second organic solvent is one of benzene, toluene, chlorobenzene, dichloromethane, chloroform and carbon tetrachloride
Or it is several.
Present invention also offers a kind of device producing methyl isocyanate, comprising:
Synthetic reaction equipment；
The sparging apparatus being connected with synthesis reactor equipment；
The de- light device being connected with the liquid outlet of sparging apparatus；
The rectifying device being connected with de- light device liquid outlet.
Preferably, also include:
The absorption equipment being connected with sparging apparatus gas outlet；
Described absorption equipment liquid outlet is connected with de- light device.
Compared with prior art, the present invention passes through directly to lead to the product of high-temperature nuclei under the conditions of 200～300 DEG C
Enter and process it is achieved that the efficiently separating of methyl isocyanate and hydrogen chloride gas in the first organic solvent, it is to avoid methyl isocyanide
Acid esters and hcl reaction generate methyl amido formyl chloride, improve the once through yield of methyl isocyanate it is not necessary to carry out many
Secondary heating and condensation, not only reduce energy consumption and the generation of by-product, do not need to arrange multiple stage decomposition in terms of device simultaneously
Reactor, greatly reduces cost of investment and production cost, test result indicate that, the methyl isocyanide acid of the method that the present invention provides
The once through yield of ester is up to 95% (in terms of monomethyl amine), high purity more than 99.5%.
Brief description
Fig. 1 produces the structural representation of the device of methyl isocyanate for the present invention.
Specific embodiment
The present invention provides a kind of preparation method of methyl isocyanate, comprising:
1) phosgene and methylamine are reacted at 300～400 DEG C, the product obtaining is maintained at 200～300 DEG C and first
Organic solvent mixes, and obtains the solution containing methyl isocyanate and the first gaseous substance；
2) organic solvent in the solution containing methyl isocyanate is removed, obtain methyl isocyanate.
According to the present invention, the present invention is first by phosgene and methylamine in 300～400 DEG C of reactions, described phosgene and a described first
The mol ratio of amine is (1.0～1.2): 1；The temperature of described reaction is preferably 350～380 DEG C.
According to the present invention, the product obtaining is maintained at 200～300 DEG C and mixes with the first organic solvent, contained
There are solution and first gaseous substance of methyl isocyanate；Described first organic solvent is benzene, toluene, chlorobenzene, dichloromethane, chlorine
One or more of imitative and carbon tetrachloride, more preferably one of toluene and chloroform or two kinds；The temperature of described product
Degree is preferably 220～250 DEG C；In order to preferably be conducive to the absorption to methyl isocyanate for first organic solvent, the present invention is excellent
The mol ratio electing methyl isocyanate and the first organic solvent in the solution containing methyl isocyanate as is 1:(4～10), more
It is preferably 1:(5～8).
The present invention passes through to react phosgene and monomethyl amine at 300～400 DEG C, and the temperature of product is on 200～300 DEG C of left sides
The right side, product all presented in methyl isocyanate, by the absorption to methyl isocyanate for first organic solvent,
Methyl isocyanate is separated well, it is to avoid methyl isocyanate and hcl reaction in condensation process with hydrogen chloride
Generate the reaction of methyl amido formyl chloride, improve yield, it is to avoid heating for multiple times and condensation, save production cost.
So that to the solution containing methyl isocyanate in do not contain impurity, it is different that preferred pair of the present invention contains methyl
The solution of cyanate carries out removing the process (referred to as " de- optical processing ") of phosgene and hydrogen chloride, the method to de- optical processing for the present invention
There is no particular/special requirement, de- optical processing well known in the art, the temperature of de- optical processing of the present invention is preferably 10～130
℃.
In order to improve the yield of methyl isocyanate further, the present invention preferably also will be organic with second for the first gaseous substance
Solvent mixes, and obtains the solution containing trace methyl isocyanates and the second gaseous substance；Described second organic solvent is preferably
One or more of benzene, toluene, chlorobenzene, dichloromethane, chloroform and carbon tetrachloride, more preferably one of toluene and chloroform
Or two kinds；First organic solvent of the present invention is preferably identical with described second organic solvent.
According to the present invention, the organic solvent in the solution containing methyl isocyanate is removed, obtains methyl isocyanate,
The present invention does not have particular/special requirement to the method removing organic solvent, well known to a person skilled in the art removing the mode of organic solvent
, the present invention preferably pass through rectification process, obtain methyl isocyanate.
The present invention passes through high-temperature reaction product is passed directly under the conditions of 200～300 DEG C process in the first organic solvent,
Achieve efficiently separating of methyl isocyanate and hydrogen chloride gas, it is to avoid methyl isocyanate and hcl reaction generate first
Base carbamyl chloride, improves the once through yield of methyl isocyanate it is not necessary to carry out heating for multiple times and condensation, not only reduces
Energy consumption and the generation of by-product, do not need to arrange multiple stage decomposition reactor simultaneously in terms of device, greatly reduce and invest into
Basis and production cost.
The present invention also provides a kind of device producing methyl isocyanate, comprising:
Synthetic reaction equipment；
The sparging apparatus being connected with synthesis reactor equipment；
The de- light device being connected with the liquid outlet of sparging apparatus；
The rectifying device being connected with de- light device liquid outlet.
Referring to Fig. 1, Fig. 1 produces the device of methyl isocyanate to the described device producing methyl isocyanate for the present invention
Structural representation, wherein, 1 is synthetic reaction equipment, and 2 is sparging apparatus, and 3 is de- light device, and 4 is rectifying device.
In the described device producing methyl isocyanate, the effect of synthetic reaction equipment 1 is to provide phosgene and monomethyl amine
The place of reaction, the gas outlet of synthetic reaction equipment 1 is connected with the air inlet of sparging apparatus 2, the effect of sparging apparatus 2 be for
Absorb the methyl isocyanate in synthetic product, thus separating methyl isocyanate and hydrogen chloride, the liquid outlet of sparging apparatus 2 with
The inlet of de- light device 3 is connected, and the effect of de- light device 3 is for the phosgene in the solution containing methyl isocyanate for the removing
And hydrogen chloride, the liquid outlet of de- light device 3 is connected with the inlet of rectifying device 4, and the effect of rectifying device 4 is by methyl isocyanide
Acid esters is separated with solvent.
In order to improve the yield of methyl isocyanate further, the device of production methyl isocyanate of the present invention is also
Including the absorption equipment 5 being connected with sparging apparatus 2 gas outlet, its effect is a small amount of first for carrying secretly in absorbing hydrogen chloride gas
Based isocyanate, the liquid outlet of described absorption equipment 5 is connected with the inlet of de- light device 3.
The device of the methyl isocyanate that the present invention provides also includes: the phosgene being connected with synthetic reaction equipment 1 air inlet
Heater 6；The monomethyl amine heater 7 being connected with synthetic reaction equipment 1 air inlet；With absorption equipment 5 gas outlet, de- light device 3
The tail gas treatment device 8 that gas outlet is connected with rectifying device 4 gas outlet；The first being connected with rectifying device 4 rectification condensate outlet
Based isocyanate pans 9；The solvent pans 10 being connected with rectifying device 4 solvent outlet, wherein, the going out of solvent pans 10
Liquid mouth is connected with the inlet of the inlet, the inlet of absorption equipment 5 and rectifying device 4 of sparging apparatus 2 respectively；With solvent
The fresh solvent storage facilities 11 that pans 10 inlet is connected.
The present invention provide production methyl isocyanate device workflow particularly as follows:
First, it is passed through phosgene and monomethyl amine in synthetic reaction equipment 1, and control the temperature of reaction to be 300～400 DEG C,
The outlet temperature of consersion unit 1 is 200～300 DEG C about, and the product in consersion unit 1 is passed through entering of sparging apparatus 2
QI KOU enters in sparging apparatus, and methyl isocyanate in product is by the solvent absorption in sparging apparatus 2, unabsorbed
The hydrogen chloride gas being mingled with methyl isocyanate enter in absorption equipment 5 by the gas outlet of sparging apparatus 2, absorption equipment 5
The micro isocyanates being mingled with the hydrogen chloride gas of methyl isocyanate absorb again, and unabsorbed hydrogen chloride passes through to absorb
The gas outlet of equipment 5 is directly entered tail gas treatment device 8；Meanwhile, the absorption in sparging apparatus 2 there is the molten of methyl isocyanate
The solution that absorption in liquid and sparging apparatus 3 has trace methyl isocyanates enters de- light by the inlet of de- light device 3
Equipment 3 carries out de- optical processing, and the gas that de- optical processing is separated is directly entered tail gas treatment device 8, after de- optical processing finishes
Solution containing methyl isocyanate enter rectifying device 4 and carry out rectification, the overhead condensation liquid in rectifying device 4 is sent into first
Based isocyanate pans 9, solvent pans 10 sent into by tower bottoms, and tower top tail gas sends into tail gas treatment device 8.
Of the present invention produce methyl isocyanate device, by by synthetic reaction equipment 1 with sparging apparatus 2 direct phase
Even so that the high temperature in consersion unit 1 generates product is directly entered sparging apparatus, it is to avoid methyl isocyanate and hydrogen chloride are anti-
The reaction of methyl amido formyl chloride should be generated, be directly isolated to obtain methyl isocyanate, and then avoid using in conventional apparatus
Decomposition reactor, not only reduce energy consumption, and effectively reduce equipment cost, simultaneously arrange absorption plant 5, reach and catch
The effect of the methyl isocyanate that collection escapes with hydrogen chloride, and then improve the yield of product, meanwhile, it is also provided with de- light
Equipment 3, the phosgene in effective demethylating isocyanate solution, and then improve the purity of methyl isocyanate.
Technical scheme is clearly and completely described it is clear that being retouched below in conjunction with the embodiment of the present invention
The embodiment stated is only a part of embodiment of the present invention, rather than whole embodiments.Based on the embodiment in the present invention, this
The every other embodiment that field those of ordinary skill is obtained under the premise of not making creative work, broadly falls into the present invention
The scope of protection.
Embodiment 1
Phosgene 5.94kg/hr and monomethyl amine 1.56kg/hr is passed through in tubular reactor, under the conditions of 330 DEG C in carry out
Reaction, the product obtaining is controlled and directly enters, from bottom, the employing automatic linkage control filling chloroform at 245 DEG C
In the bubble tower of liquid level, the methyl isocyanate of solubility is absorbed by chloroform, and the solution containing methyl isocyanate is sent
Enter de- light tower, in bubble tower, methyl isocyanate and chloroform mol ratio are 1:6,55 DEG C of operation temperature.Bubbling overhead gas
Enter absorption tower absorb, 35 DEG C of absorption tower operation temperature, after absorption, kettle liquid pumps into de- light tower, overhead gas through overhead condenser at
Exhaust treatment system is entered after reason；The solution containing methyl isocyanate from bubble tower and absorption tower is adopted in tower reactor liquid level
Carry out phosgene removing process, tower reactor operation temperature is 45 DEG C, and de- light overhead gas are through tower in the de- light tower being controlled with automatic linkage
Top condenser enters exhaust treatment system after processing；The solution containing methyl isocyanate after de- light enters rectifying column and enters
Row rectification process, tower bottoms enters solvent medial launder and recycles, and tower top obtains rectification product methyl isocyanate 2.78kg/
Hr, yield is 97.4% (in terms of monomethyl amine).
Detected by the isocyanates that high performance liquid chromatography obtains to embodiment 1, test result indicate that, its purity is
99.6%.
Embodiment 2
Phosgene 5.44kg/hr and monomethyl amine 1.56kg/hr is passed through in tubular reactor, under the conditions of 350 DEG C in carry out
Reaction, the product obtaining is controlled and directly enters, from bottom, the employing automatic linkage control filling chloroform at 260 DEG C
In the bubble tower of liquid level, the methyl isocyanate of solubility is absorbed by chloroform, and the solution containing methyl isocyanate is sent
Enter de- light tower, in bubble tower, methyl isocyanate and chloroform mol ratio are 1:8,50 DEG C of operation temperature.Bubbling overhead gas
Enter absorption tower absorb, 38 DEG C of absorption tower operation temperature, after absorption, kettle liquid pumps into de- light tower, overhead gas through overhead condenser at
Exhaust treatment system is entered after reason；The solution containing methyl isocyanate from bubble tower and absorption tower is adopted in tower reactor liquid level
Carry out phosgene removing process, tower reactor operation temperature is 50 DEG C, and de- light overhead gas are through tower in the de- light tower being controlled with automatic linkage
Top condenser enters exhaust treatment system after processing；The solution containing methyl isocyanate after de- light enters rectifying column and enters
Row rectification process, tower bottoms enters solvent medial launder and recycles, and tower top obtains rectification product methyl isocyanate 2.74kg/
Hr, yield is 96.2% (in terms of monomethyl amine).
Detected by the isocyanates that high performance liquid chromatography obtains to embodiment 1, test result indicate that, its purity is
99.7%.
Embodiment 3
Phosgene 81.6kg/hr and monomethyl amine 23.3kg/hr is passed through tubular reactor, under the conditions of 350 DEG C in carry out anti-
Should, the product obtaining is controlled and directly enters, from bottom, the employing automatic linkage control liquid filling chloroform at 245 DEG C
In the bubble tower of position, the methyl isocyanate of solubility is absorbed by chloroform, and the solution containing methyl isocyanate is sent into
De- light tower, in bubble tower, methyl isocyanate and chloroform mol ratio are 1:5,62 DEG C of operation temperature.Bubbling overhead gas enter
Enter absorption tower to absorb, 33 DEG C of absorption tower operation temperature, after absorption, kettle liquid pumps into de- light tower, overhead gas are processed through overhead condenser
Enter exhaust treatment system afterwards；The solution containing methyl isocyanate from bubble tower and absorption tower is adopted in tower reactor liquid level
Carry out phosgene removing process, tower reactor operation temperature is 62 DEG C, and de- light overhead gas are through tower top in the de- light tower that automatic linkage controls
Condenser enters exhaust treatment system after processing；The solution containing methyl isocyanate after de- light enters rectifying column to be carried out
Rectification process, tower bottoms enters solvent medial launder and recycles, and tower top obtains rectification product methyl isocyanate 40.8kg/hr,
Yield is 95.5% (in terms of monomethyl amine).
Detected by the methyl isocyanate that high performance liquid chromatography obtains to embodiment 1, test result indicate that, it is pure
Spend for 99.6%.
The explanation of above example is only intended to help and understands the method for the present invention and its core concept.It should be pointed out that it is right
For those skilled in the art, under the premise without departing from the principles of the invention, the present invention can also be carried out
Some improvement and modification, these improve and modify and also fall in the protection domain of the claims in the present invention.
Claims (7)
1. a kind of preparation method of methyl isocyanate, comprising:
1) phosgene and monomethyl amine are reacted at 350～380 DEG C, the product obtaining is maintained at 220～250 DEG C to be had with first
Machine solvent mixes, and obtains the solution containing methyl isocyanate and the first gaseous substance；Described molten containing methyl isocyanate
In liquid, the mol ratio of methyl isocyanate and the first organic solvent is 1:(4～10)；
2) organic solvent in the solution containing methyl isocyanate is removed, obtain methyl isocyanate.
2. preparation method according to claim 1 is it is characterised in that described phosgene with the mol ratio of described monomethyl amine is
(1.0～1.2): 1.
3. preparation method according to claim 1 it is characterised in that described first organic solvent be benzene, toluene, chlorobenzene,
One or more of dichloromethane, chloroform and carbon tetrachloride.
4. preparation method according to claim 1 is it is characterised in that described step 1) after step 2) before also include:
Solution containing methyl isocyanate is carried out removing the process of phosgene and hydrogen chloride.
5. preparation method according to claim 4 is it is characterised in that the temperature of described removing phosgene and hydrochlorination is
10～130 DEG C.
6. preparation method according to claim 1 is it is characterised in that described step 1) after also include described first gas
Phase material is mixed with the second organic solvent, obtains the solution containing trace methyl isocyanates and the second gaseous substance.
7. preparation method according to claim 6 it is characterised in that described second organic solvent be benzene, toluene, chlorobenzene,
One or more of dichloromethane, chloroform and carbon tetrachloride.
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| CN201410767754.XA CN104387295B (en) | 2014-12-12 | 2014-12-12 | Preparation method of methyl isocyanate |
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| CN104387295B true CN104387295B (en) | 2017-01-25 |
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Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN109507345B (en) * | 2017-09-15 | 2022-08-05 | 万特制药(海南)有限公司 | Rivastigmine bitartrate intermediate and separation and determination method of impurities thereof |
| CN107935889B (en) * | 2017-11-29 | 2020-08-28 | 万华化学集团股份有限公司 | Preparation method and device of monoisocyanate |
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|---|---|---|---|---|
| US3969389A (en) * | 1974-03-11 | 1976-07-13 | Basf Aktiengesellschaft | Manufacture of aliphatic isocyanates |
| US4082787A (en) * | 1977-01-03 | 1978-04-04 | E. I. Du Pont De Nemours And Company | Methyl isocyanate process |
| CN86100286A (en) * | 1986-01-15 | 1986-07-16 | 湖南化工研究所 | Method for preparing methyl isocyanate |
| CN101671273A (en) * | 2009-09-18 | 2010-03-17 | 天津大学 | Method for recycling phosgene in continuous production process of toluene di-isocyanate |
| CN102976976A (en) * | 2012-11-29 | 2013-03-20 | 湖南化工研究院 | Preparation method for methyl isocyanate |
| CN103694190A (en) * | 2013-12-25 | 2014-04-02 | 沙隆达集团公司 | Production method and equipment of methyl isocyanate |
-
2014
- 2014-12-12 CN CN201410767754.XA patent/CN104387295B/en active Active
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3969389A (en) * | 1974-03-11 | 1976-07-13 | Basf Aktiengesellschaft | Manufacture of aliphatic isocyanates |
| US4082787A (en) * | 1977-01-03 | 1978-04-04 | E. I. Du Pont De Nemours And Company | Methyl isocyanate process |
| CN86100286A (en) * | 1986-01-15 | 1986-07-16 | 湖南化工研究所 | Method for preparing methyl isocyanate |
| CN101671273A (en) * | 2009-09-18 | 2010-03-17 | 天津大学 | Method for recycling phosgene in continuous production process of toluene di-isocyanate |
| CN102976976A (en) * | 2012-11-29 | 2013-03-20 | 湖南化工研究院 | Preparation method for methyl isocyanate |
| CN103694190A (en) * | 2013-12-25 | 2014-04-02 | 沙隆达集团公司 | Production method and equipment of methyl isocyanate |
Non-Patent Citations (1)
| Title |
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| 甲基异氰酸酯制造方法;陈世珍等;《农药工业译丛》;19800828;第18-22页 * |
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