CN109776332A - A kind of method that continous way adds hydrogen to prepare 2,4- dimethylaniline - Google Patents
A kind of method that continous way adds hydrogen to prepare 2,4- dimethylaniline Download PDFInfo
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- CN109776332A CN109776332A CN201910133643.6A CN201910133643A CN109776332A CN 109776332 A CN109776332 A CN 109776332A CN 201910133643 A CN201910133643 A CN 201910133643A CN 109776332 A CN109776332 A CN 109776332A
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Abstract
The present invention provides a kind of continous ways, and hydrogen to be added to prepare 2, the method of 4- dimethylaniline, this method comprises: by 2,4- dimethyl nitrobenzene solution is after heat exchange, entered in reactor by side, reactor is provided with more hollow Hydrogen distribution pipes, catalyst is filled in the interlayer of Hydrogen distribution pipe and reactor, Hydrogen distribution pipe and catalyst contact position have a large amount of tiny apertures, hydrogen by distributor pipe upper end enter after through hole track overflow, it mixes with material liquid and is reacted by catalyst bed, generate product 2,4- dimethylaniline；The solvent of the 2,4- dimethyl nitrobenzene solution is one of water, methanol and ethyl alcohol or a variety of.The method of the present invention uses unique reactor and technological design, compared to conventional batch reaction process, it can be achieved that continuous, the Efficient Conversion of 2,4- dimethyl nitrobenzenes.1000h, feed stock conversion > 90% are continuously run using this method, product selectivity is greater than 98%.
Description
Technical field
The present invention relates to a kind of methods that continous way adds hydrogen to prepare 2,4- dimethylaniline.
Background technique
2,4- dimethylanilines both can be used as the production of the organic nitrogens pesticides such as Amitraz, single carbonamidine in the industry, can also
It is a kind of important fine chemical product for the synthesis of the organic dyestuff such as acetyl waste water, benzidine yellow, lemon yellow.
2,4- dimethylaniline is prepared by 2,4- dimethyl nitrobenzene, traditional method is iron powder reducing method, which adopts
It is operated with batch tank, it is the method that many small business use, but the method occupation area of equipment is big that route is mature, operation effect
Rate is low, on the verge of being replaced.Catalytic hydrogenating reduction method is the main method for substituting iron powder reducing method, Chinese patent
CN1065858C discloses a kind of new process that N- monoalkyl arylamine is prepared using aromatic nitro object as raw material, what this method used
Skeleton nickel is both reducing catalyst and N- alkylation catalyst, can not separate reduzate direct alkylation in a kettle
N- monoalkyl arylamine is made；Chinese patent CN101863777B discloses one kind with 2,4- dimethyl nitrobenzene or 2,6- dimethyl
Nitrobenzene is raw material, not solubilizer, using Raney nickel, under 1.0~2.5MPa reaction pressure, 60~120 DEG C of reaction temperatures
The method for preparing arylamine product.Although the yield of above-mentioned two methods product is higher, it is all made of batch tank operation, equipment
Occupied area is larger, and cost of labor is big.
Method disclosed in Chinese patent CN100439324C be using aromatic nitro object as raw material, using methanol as solvent, with
Raney's nickel is catalyst, under 1.0~4.0MPa reaction pressure, 80~250 DEG C of reaction temperatures, by autoclave or fixation
Bed one step of tubular reactor prepares N- alkylarylamine.But the method reaction temperature is higher, energy consumption is high, and early period need to seal Raney's nickel
Yu Shuizhong is saved, and is packed into fixed bed afterwards, and operating process has some potential safety problems.
Summary of the invention
The object of the present invention is to provide a kind of methods that continous way adds hydrogen preparation 2,4- dimethylaniline, and the method is using unique
Reactor and technological design, compare conventional batch reaction process, it can be achieved that 2,4- dimethyl nitrobenzenes it is continuous, efficiently turn
Change.
It is the concrete scheme that the present invention uses below.
The present invention provides one kind by 2,4- dimethyl nitrobenzene continous way add hydrogen preparation 2,4- dimethylaniline method,
Include: by concentration be 1.0~5.0mol/L 2,4- dimethyl nitrobenzene solution by heat exchange after, reactor is entered by side
In, reactor is provided with more hollow Hydrogen distribution pipes, and Catalyst packing is in the interlayer of Hydrogen distribution pipe and reactor, hydrogen
Gas distributor pipe and catalyst contact position there are a large amount of tiny apertures, hydrogen to be entered by distributor pipe upper end after through hole track overflow, with original
Feed liquid mixing reacted by catalyst bed, control average reaction temperature be 30~100 DEG C, Hydrogen Vapor Pressure be 0.5~
4.0MPa, liquid feed volume air speed are 0.5~4.5h-1, air inlet and feed liquor volume ratio are 40~400:1, generate product 2,4-
Dimethylaniline；
Solvent is one of water, methanol and ethyl alcohol or a variety of in the raw material 2,4- dimethyl nitrobenzene solution.
In the above-mentioned technical solutions, wherein the concentration of 2,4- dimethyl nitrobenzenes preferably 1.0~3.0mol/L.
The catalyst is made of carrier to load metal active component, and metal active constituent is MoO preferably wherein3、WO3、
NiO、Co2O3One of or it is a variety of, total metal oxide quality accounts for the 10.0%~35.0% of catalyst quality, preferably
15.0%~30.0%, surplus is carrier, and carrier is made of aluminium oxide, and specific surface area of catalyst is 80~180m2/ g, preferably
110~180m2/ g, Kong Rongwei 0.3~0.8mL/g, preferably 0.4~0.7mL/g.
The hydrogen is mixed with material liquid when being reacted by catalyst bed, preferably average reaction temperature be 35~
80 DEG C, Hydrogen Vapor Pressure is 0.5~3.0MPa, and liquid feed volume air speed is 0.7~3.5h-1, air inlet and feed liquor volume ratio are 60
~300:1.
This method uses unique reactor design, compared to traditional batch still reaction technique, it can be achieved that 2,4- dimethyl
The continuous preparation of nitroaniline, effectively improves production efficiency, saves the device space；Meanwhile the catalyst that this method is selected
Catalytic activity is high, and product selectivity is strong, and the Efficient Conversion of raw material need to be only achieved that under 35~80 DEG C of reaction temperatures.Using this
Method continuously runs 1000h, feed stock conversion > 90%, and product selectivity is greater than 98%.
Detailed description of the invention
Fig. 1 is that continous way of the present invention adds hydrogen to prepare the process flow diagram of 2,4- dimethylaniline method.
In figure, 1 is heat exchanger, and 2 be reactor, and 3 be separator.
Specific embodiment
It is described in detail below with reference to the method that Fig. 1 adds hydrogen to prepare 2,4- dimethylaniline continous way of the present invention.
Raw material 2, the solution of 4- dimethyl nitrobenzene is introduced into heat exchanger 1, after being heated to certain temperature, by side into
Enter in reactor 2, reactor 2 is provided with more hollow Hydrogen distribution pipes, and Catalyst packing is in Hydrogen distribution pipe and reactor 2
Interlayer in, Hydrogen distribution pipe and catalyst contact position there are a large amount of tiny apertures, hydrogen to be entered by distributor pipe upper end after through hole
Track overflow is mixed with material liquid and is reacted by catalyst bed, generate product 2,4- dimethylaniline, gas-liquid mixture from
Reactor 2 enters in separator 3 after flowing out, and a small amount of unreacted hydrogen separated in separator 3 returns to compressor, after pressurization
It can be recycled, 2,4- dimethyl benzene amine product can be obtained in the reaction mixture of liquid phase part after separating again.
Below by 5 embodiments, the invention will be further described.5 embodiments are all made of same catalyst,
Its physical index is as shown in table 1.
The composition and main character of 1 catalyst of table
The content of 2,4- dimethyl nitrobenzene and 2 in solution, 4- dimethylaniline passes through chromatographic, using interior
Mark method acquires.
Embodiment 1:
2,4- dimethyl nitrobenzene is dissolved in the solution for being made into that concentration is 2.0mol/L in anhydrous methanol, heat exchanger is passed through and adds
Heat is to 70 DEG C as reaction liquid phase feeding.Adjusting Hydrogen Vapor Pressure in reactor is 1.0MPa, and solution enters from reactor side, into
Material volume space velocity is 0.6h-1, hydrogen enters by reactor upper end, and air inlet and feed liquor volume ratio are 80:1.Mixed liquor after reaction
Into gas-liquid separation is carried out in separator, 2,4- dimethyl nitro is calculated through chromatographic in gained liquid product
The conversion ratio of benzene is 94.2%, and the selectivity of 2,4- dimethylanilines is 98.7%.
Embodiment 2:
2,4- dimethyl nitrobenzene is dissolved in the solution for being made into that concentration is 2.2mol/L in anhydrous methanol, heat exchanger is passed through and adds
Heat is to 75 DEG C as reaction liquid phase feeding.Adjusting Hydrogen Vapor Pressure in reactor is 1.5MPa, and solution enters from reactor side, into
Material volume space velocity is 0.8h-1, hydrogen enters by reactor upper end, and air inlet and feed liquor volume ratio are 100:1.Mixed liquor after reaction
Into gas-liquid separation is carried out in separator, 2,4- dimethyl nitro is calculated through chromatographic in gained liquid product
The conversion ratio of benzene is 96.6%, and the selectivity of 2,4- dimethylanilines is 98.4%.
Embodiment 3:
2,4- dimethyl nitrobenzene is dissolved in the solution for being made into that concentration is 2.5mol/L in anhydrous methanol, heat exchanger is passed through and adds
Heat is to 77 DEG C as reaction liquid phase feeding.Adjusting Hydrogen Vapor Pressure in reactor is 2.0MPa, and solution enters from reactor side, into
Material volume space velocity is 1.0h-1, hydrogen enters by reactor upper end, and air inlet and feed liquor volume ratio are 150:1.Mixed liquor after reaction
Into gas-liquid separation is carried out in separator, 2,4- dimethyl nitro is calculated through chromatographic in gained liquid product
The conversion ratio of benzene is 92.7%, and the selectivity of 2,4- dimethylanilines is 99.1%.
Embodiment 4:
2,4- dimethyl nitrobenzene is dissolved in the solution for being made into that concentration is 2.0mol/L in dehydrated alcohol, heat exchanger is passed through and adds
Heat is to 70 DEG C as reaction liquid phase feeding.Adjusting Hydrogen Vapor Pressure in reactor is 1.5MPa, and solution enters from reactor side, into
Material volume space velocity is 0.8h-1, hydrogen enters by reactor upper end, and air inlet and feed liquor volume ratio are 100:1.Mixed liquor after reaction
Into gas-liquid separation is carried out in separator, 2,4- dimethyl nitro is calculated through chromatographic in gained liquid product
The conversion ratio of benzene is 95.1%, and the selectivity of 2,4- dimethylanilines is 99.2%.
Embodiment 5:
2,4- dimethyl nitrobenzene is dissolved in the solution for being made into that concentration is 2.5mol/L in dehydrated alcohol, heat exchanger is passed through and adds
Heat is to 75 DEG C as reaction liquid phase feeding.Adjusting Hydrogen Vapor Pressure in reactor is 2.0MPa, and solution enters from reactor side, into
Material volume space velocity is 1.0h-1, hydrogen enters by reactor upper end, and air inlet and feed liquor volume ratio are 250:1.Mixed liquor after reaction
Into gas-liquid separation is carried out in separator, 2,4- dimethyl nitro is calculated through chromatographic in gained liquid product
The conversion ratio of benzene is 94.9%, and the selectivity of 2,4- dimethylanilines is 98.3%.
Claims (5)
1. a kind of continous way adds the method for hydrogen preparation 2,4- dimethylaniline characterized by comprising
By concentration be 1.0~5.0mol/L 2,4- dimethyl nitrobenzene solution by heat exchange after, entered in reactor by side,
Reactor is provided with more hollow Hydrogen distribution pipes, is filled with catalyst, hydrogen in the interlayer of Hydrogen distribution pipe and reactor
Distributor pipe and catalyst contact position there are a large amount of tiny apertures, hydrogen to be entered by distributor pipe upper end after through hole track overflow, with raw material
Liquid mixing is reacted by catalyst bed, generates product 2,4- dimethylaniline；Wherein control average reaction temperature is 30
~100 DEG C, Hydrogen Vapor Pressure is 0.5~4.0MPa, and liquid feed volume air speed is 0.5~4.5h-1, air inlet is with feed liquor volume ratio
40~400:1；
The solvent of the 2,4- dimethyl nitrobenzene solution is one of water, methanol and ethyl alcohol or a variety of.
2. a kind of continous way according to claim 1 adds the method for hydrogen preparation 2,4- dimethylaniline, it is characterised in that institute
The catalyst stated is made of carrier to load metal active component, and wherein metal active constituent is MoO3、WO3、NiO、Co2O3In
One or more, total metal oxide quality accounts for the 10.0%~35.0% of catalyst quality, and surplus is carrier, and carrier is by aoxidizing
Aluminium is made, and specific surface area of catalyst is 80~180m20.3~0.8mL/g of/g, Kong Rongwei.
3. a kind of continous way according to claim 1 adds the method for hydrogen preparation 2,4- dimethylaniline, which is characterized in that institute
The catalyst stated is made of carrier to load metal active component, and wherein metal active constituent is MoO3、WO3、NiO、Co2O3In
One or more, total metal oxide quality accounts for the 15.0%~30.0% of catalyst quality, and surplus is carrier, and carrier is by aoxidizing
Aluminium is made, and specific surface area of catalyst is 110~180m20.4~0.7mL/g of/g, Kong Rongwei.
4. a kind of continous way according to claim 1 adds the method for hydrogen preparation 2,4- dimethylaniline, which is characterized in that its
The concentration of middle 2,4- dimethyl nitrobenzene is 1.0~3.0mol/L.
5. a kind of continous way according to claim 1 adds the method for hydrogen preparation 2,4- dimethylaniline, which is characterized in that institute
The hydrogen stated mixes the reaction condition to react by catalyst bed with material liquid are as follows: average reaction temperature is 35~80
DEG C, Hydrogen Vapor Pressure is 0.5~3.0MPa, and liquid feed volume air speed is 0.7~3.5h-1, air inlet and feed liquor volume ratio be 60~
300:1.
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114307862A (en) * | 2021-12-01 | 2022-04-12 | 中海油天津化工研究设计院有限公司 | Method for preparing methyl substituted aniline through membrane dispersion hydrogenation |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1055922A (en) * | 1990-04-21 | 1991-11-06 | 浙江工学院 | 2,4-xylidine and 2, the preparation method of 6-xylidine |
| CN1633408A (en) * | 2002-02-15 | 2005-06-29 | 巴斯福股份公司 | Method for the production of amines |
| US20110295039A1 (en) * | 2010-05-17 | 2011-12-01 | Basf Se | Process for preparing toluenediamine by hydrogenation of dinitrotoluene |
-
2019
- 2019-02-22 CN CN201910133643.6A patent/CN109776332A/en active Pending
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1055922A (en) * | 1990-04-21 | 1991-11-06 | 浙江工学院 | 2,4-xylidine and 2, the preparation method of 6-xylidine |
| CN1633408A (en) * | 2002-02-15 | 2005-06-29 | 巴斯福股份公司 | Method for the production of amines |
| US20110295039A1 (en) * | 2010-05-17 | 2011-12-01 | Basf Se | Process for preparing toluenediamine by hydrogenation of dinitrotoluene |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114307862A (en) * | 2021-12-01 | 2022-04-12 | 中海油天津化工研究设计院有限公司 | Method for preparing methyl substituted aniline through membrane dispersion hydrogenation |
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Application publication date: 20190521 |