CN109867606A - A kind of preparation process of p-phenylenediamine - Google Patents
A kind of preparation process of p-phenylenediamine Download PDFInfo
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Abstract
The invention discloses a kind of preparation processes of p-phenylenediamine, the p-phenylenediamine is using paranitroanilinum and hydrogen as raw material, using methanol as solvent, reduction reaction is carried out using Raney Ni catalyst, p-phenylenediamine crystal grain is added into the solution after reaction as crystal seed, pass through repeated multiple times heating, temperature-fall period carries out crystallization, separation crystal is drying to obtain the p-phenylenediamine, so that the crystallization of p-phenylenediamine shows repeatedly circulating precipitation and dissolution, generate multiple recrystallization, the time of its purifying is reduced while improving p-phenylenediamine purity, more uniform crystal is also formed simultaneously.
Description
Technical field
The present invention relates to the production technical fields of p-phenylenediamine, and in particular to a kind of preparation process of p-phenylenediamine.
Background technique
P-phenylenediamine is a kind of important Organic Chemicals, mainly for the production of dyestuff, rubber antioxidant etc..Tradition
P-phenylenediamine production method be using paranitrochlorobenzene as raw material, reacted under high temperature and pressure with ammonium hydroxide (or ammonia) preparation pair
Nitroaniline, paranitroanilinum generate p-phenylenediamine crude product through akali sulphide or iron powder reducing again, are most made afterwards through recrystallization purification
High-purity p-phenylenediamine.The maximum defect of the technique is that industrial wastewater is more, and iron powder reducing generates a large amount of iron cements, seriously pollutes ring
Border, and low temperature sedimentation is usually used in purification and is separated for the technique, i.e., realizes the solution after reaction through supercooling
Then the crystal that p-phenylenediamine is precipitated in cooling is being dried, traditional cooling be precipitated is usually gradually to analyse by continued down
Crystal out, although this mode can obtain more pure crystal, the duration is longer, by p-phenylenediamine
Chemical property influence its be lost in this very long crystallization process it is also larger.
Summary of the invention
For above-mentioned technical deficiency, the object of the present invention is to provide a kind of preparation processes of p-phenylenediamine, use
The production method of hydrogen reducing reduces the environmental pollution of production, while being improved using the stepped type of cooling is recycled to benzene
Purification time is reduced while the yield of diamines, reduces the loss of p-phenylenediamine.
In order to solve the above technical problems, the present invention adopts the following technical scheme:
The present invention provides a kind of preparation process of p-phenylenediamine, and the p-phenylenediamine is original with paranitroanilinum and hydrogen
Material carries out reduction reaction using Raney Ni catalyst, p-phenylenediamine is added into the solution after reaction using methanol as solvent
Crystal grain carries out crystallization as crystal seed, by repeated multiple times heating, cooling process, and separation crystal is drying to obtain described to benzene two
Amine.
Preferably, the repeated multiple times heating, cooling process is as follows:
(1) it after p-phenylenediamine crystal grain being added, stirs evenly, is then lifted out the temperature of reaction kettle to 64 DEG C, forms saturation
P-phenylenediamine methanol solution, is then rapidly cooled to 50 DEG C for solution temperature, and the crystal of a part of p-phenylenediamine is precipitated again simultaneously
10min is stood, 30 DEG C then are rapidly cooled to solution, stands 0.5 hour；Temperature of reaction kettle is then to slowly warm up to 60
℃；
(2) temperature of reaction kettle is then rapidly cooled to 20 DEG C, stands 0.5 hour, then temperature of reaction kettle is slowly heated up
To 50 DEG C, 0.5 hour is stood, solution is then rapidly cooled to 20 DEG C；
(3) when solution is cooled to 20 DEG C, 0.5h is stood, and promote the mixing speed of reaction kettle, it is then that solution is rapid
10 DEG C are cooled to, stands 0.5 hour.
Preferably, the preparation process of p-phenylenediamine specifically comprises the following steps:
Step 1: paranitroanilinum, methanol and Raney Ni catalyst are put into reaction kettle, wherein p-nitrophenyl
The mass ratio of amine and methanol solvate is 1:15, and Raney Ni catalyst charge is the 3% of paranitroanilinum quality；It is passed through nitrogen
Gas is replaced, and displacement number is not less than 2 times；Hydrogen is then passed to, starts reaction kettle for temperature and rises to 50 DEG C, pressure rises to
2.5MPa, and its revolving speed is promoted to 1000rpm by the blender for starting reaction kettle simultaneously, is reacted, the reaction time is not less than
1.5 hour；After reaction, by the pressure pressure release of reaction kettle to normal pressure state, the temperature of reaction kettle is promoted to 64 DEG C, it will be anti-
The revolving speed of kettle is answered to be reduced to 500rpm；
Step 2: and then p-phenylenediamine crystal grain is put into the solution of step 1 after reaction, until p-phenylenediamine is no longer
Dissolution, forms the p-phenylenediamine methanol solution of saturation, stirs evenly, solution temperature is then rapidly cooled to 50 DEG C, is analysed again
The crystal of a part of p-phenylenediamine and 10min is stood out, 30 DEG C then are rapidly cooled to solution, stands 0.5 hour；Then
Temperature of reaction kettle is to slowly warm up to 60 DEG C；
Step 3: the solution after step 2 is heated up is rapidly cooled to 20 DEG C, stands 0.5 hour, then will react kettle temperature
Degree is to slowly warm up to 50 DEG C, stands 0.5 hour, solution is then rapidly cooled to 20 DEG C；
Step 4: when solution is cooled to 20 DEG C, standing 0.5h, and promotes the mixing speed of reaction kettle to 800rpm, with
Solution is rapidly cooled to 10 DEG C afterwards, stands 0.5 hour；
Step 5: the p-phenylenediamine crystal that separating step four obtains, and be dried in vacuo, obtain p-phenylenediamine finished product.
Preferably, the speed cooled down rapidly is 2 DEG C/min, and the speed slowly to heat up is 30 DEG C/h.
Preferably, the vacuum drying temperature is 80 DEG C.
The beneficial effects of the present invention are:
(1) present invention realizes ring compared to traditional production method as raw material by paranitroanilinum and hydrogen
Production is protected, the discharge of pollutant is reduced；
(2) present invention is using the purification for recycling stepped heating cooling method progress p-phenylenediamine, so that p-phenylenediamine
Crystallization show repeatedly circulating precipitation and dissolution, generate multiple recrystallization, realize and improve p-phenylenediamine yield
The time for reducing its purifying simultaneously, obtain the p-phenylenediamine of high-purity；And one is generated by fast cooling and slowly heating
Kind dynamic recrystallization adjustment, forms more uniform crystal；Furthermore the mode of this recrystallization is a kind of staged, each knot
Brilliant temperature is different, and stepped reduction is presented, so that the p-phenylenediamine crystal of some is deposited in the solution when recycling every time
(forming oversaturated p-phenylenediamine methanol solution), and these crystal exist for crystallizing next time and play inducing action,
Promote p-phenylenediamine crystallization.
Specific embodiment
Below in conjunction with the embodiment of the present invention, technical solution in the embodiment of the present invention is clearly and completely retouched
It states, it is clear that described embodiments are only a part of the embodiments of the present invention, instead of all the embodiments.Based on the present invention
In embodiment, every other implementation obtained by those of ordinary skill in the art without making creative efforts
Example, shall fall within the protection scope of the present invention.
Embodiment 1:
In order to facilitate experiment, in the present embodiment, the mass ratio of paranitroanilinum and methanol solvate is 1:15, to nitro
The mass ratio of aniline and hydrogen is not more than 1/3, and paranitroanilinum takes 1.38kg in the present embodiment, and Raney Ni catalyst accounts for
The quality of paranitroanilinum is 3% i.e. 0.0414kg；
Step 1: raw material is prepared according to the mass ratio of paranitroanilinum, methanol solvate and Raney Ni catalyst；Together
When prepares a certain amount of p-phenylenediamine crystal grain, and (its preparation amount will just form the p-phenylenediamine first of saturation under conditions of 64 DEG C
Alcoholic solution), size of microcrystal is between 0.5mm-0.8mm；Paranitroanilinum, methanol and Raney are put into reaction kettle
Ni catalyst is passed through nitrogen and is replaced, and displacement number is not less than 2 times；Then pass to hydrogen (hydrogen is excessive), starting reaction
Temperature is risen to 50 DEG C by kettle, and pressure rises to 2.5MPa, and its revolving speed is promoted to by the blender for starting reaction kettle simultaneously
1000rpm is reacted, and the reaction time 1.5 hours；After reaction, by the pressure pressure release of reaction kettle to normal pressure state (i.e.
Atmospheric pressure), the temperature of reaction kettle is promoted to 64 DEG C of (reaction kettle highests it is contemplated herein that arrive the boiling point of methanol, therefore after being promoted
Temperature outline is lower than its boiling point), the revolving speed of reaction kettle is reduced to 500rpm；
Step 2: prepared p-phenylenediamine crystal grain is put into as crystal seed, just into step 1 solution after reaction
The p-phenylenediamine methanol solution for forming saturation, stirs evenly, solution temperature is then cooled to 50 DEG C with the speed of 2 DEG C/min,
Again the crystal of a part of p-phenylenediamine is precipitated and stands 10min, solution is then cooled to 30 with the speed of 2 DEG C/min again
DEG C, stand 0.5 hour；Temperature of reaction kettle is then warming up to 60 DEG C with the speed of 30 DEG C/min；
Step 3: the solution after step 2 is heated up is cooled to 20 DEG C with the speed of 2 DEG C/min, stands 0.5 hour, so
Temperature of reaction kettle is warming up to 50 DEG C with the speed of 30 DEG C/min afterwards, stands 0.5 hour, then with the speed of 2 DEG C/h by solution
It is cooled to 20 DEG C；
Step 4: when solution is cooled to 20 DEG C, standing 0.5h, and promotes the mixing speed of reaction kettle to 800rpm, with
Solution is cooled to 10 DEG C with the speed of 2 DEG C/min afterwards, stands 0.5 hour；
Step 5: the p-phenylenediamine crystal that separating step four obtains, and be dried in vacuo at 80 DEG C, drying time
Not less than 1 hour, p-phenylenediamine finished product is obtained, and weigh to it, the weight of acquisition is subtracted to pair being added in step 2
Phenylenediamine, the clear weight of final p-phenylenediamine are 1.07561kg, then yield is that 1.07561/1.08=99.59% is (resonable
Think that the paranitroanilinum of 1.38kg under state converts the p-phenylenediamine that can obtain 1.08kg completely, in this application p-phenylenediamine phase
Molecular mass value 108), by chromatographic, the purity of the p-phenylenediamine of acquisition is 99.76%, to pair of acquisition
The partial size of the crystal of phenylenediamine measures, and measures the range of its size of microcrystal, compares the uniformity, warp by the span of partial size
Its particle size range is measured substantially between 0.6mm-1.0mm, more uniformly.
Comparative example 1:
On the basis of embodiment 1, same raw material and dosage are chosen,
Step 1: raw material is prepared according to the mass ratio of paranitroanilinum, methanol solvate and Raney Ni catalyst；To
Investment paranitroanilinum, methanol and Raney Ni catalyst, are passed through nitrogen and are replaced in reaction kettle, and displacement number is not low
In 2 times；Hydrogen (hydrogen is excessive) is then passed to, starts reaction kettle for temperature and rises to 50 DEG C, pressure rises to 2.5MPa, and simultaneously
Its revolving speed is promoted to 1000rpm by the blender of starting reaction kettle, is reacted, the reaction time 1.5 hours；After reaction,
By the pressure pressure release of reaction kettle to normal pressure state (i.e. atmospheric pressure), holding temperature of reaction kettle is constant, and (temperature of reaction kettle is 50 at this time
DEG C), the revolving speed of reaction kettle is reduced to 500rpm；Solution temperature is then cooled to 20 DEG C with the speed of 2 DEG C/h, is promoted anti-
It answers the mixing speed of kettle to 800rpm, continues that solution is cooled to 10 DEG C with the speed of 2 DEG C/min, stand 1 hour；
Step 3: the p-phenylenediamine crystal that separating step two obtains, and be dried in vacuo at 80 DEG C, drying time
Not less than 1 hour, p-phenylenediamine finished product is obtained.
Wherein comparative example 1 the difference from embodiment 1 is that, comparative example 1 directly carries out the solution after reaction at cooling
Reason, lacks induction, i.e., 10 DEG C is reduced to from 50 DEG C with the speed of 2 DEG C/h, centre is without the circulate operation to cool down that heats up, no
Generate multiple recrystallize；It weighs to the p-phenylenediamine obtained in this comparative example, the weight for obtaining p-phenylenediamine is
0.96882kg, then yield is 0.96882/1.08=89.71%, by chromatographic, the p-phenylenediamine of acquisition
Purity is 94.32%, and the p-phenylenediamine crystal uniformity obtained is less than embodiment 1；It can be seen that this comparative example compared to
Embodiment 1 does not generate multiple precipitation and dissolution (repeated recrystallize), obtains without multiple heating down cycles
The yield and purity of p-phenylenediamine generate reduction, and the crystal of p-phenylenediamine can not also carry out the adjustment of repeated recrystallize, to obtaining
The partial size of the crystal of the p-phenylenediamine obtained measures, and is measured its particle size range substantially between 0.7mm-1.5mm, end
Point value and span are all larger than embodiment 1, and the uniformity is less than embodiment 1.
Comparative example 2:
On the basis of comparative example 1, the time of repose in the step of comparative example 1 one is extended into 4h, other are constant, right
The phenylenediamine of acquisition is weighed, and the weight for obtaining p-phenylenediamine is 1.02463kg, then yield is 1.02463/1.08=
94.87%, by chromatographic, the purity of the p-phenylenediamine of acquisition is 95.82%, it can be seen that without more
It needs further to increase time of repose in the case where secondary heating down cycles, so that crystallization is sufficiently precipitated, simultaneously because
The growth of time of repose is influenced by p-phenylenediamine chemical property, and loss increases, and purity also reduces accordingly.In reality
Industrial production in, what material quantity used in production will be big compared to the material quantity in the application is more, and then in practical life
In production, actual time of repose may require that longer, virtually increases p-phenylenediamine purification time, increases its waste；
Comparative example 3:
On the basis of comparative example 1, other are constant, will compare the solution type of cooling after reaction in 1 step 1
Modification are as follows:
Solution temperature after reaction is cooled to 40 DEG C with the speed of 2 DEG C/h, stands 10min；Then at a same speed
30 DEG C are cooled to, 10min is stood；Then it is cooled to 20 DEG C at a same speed, stands 10min；It is last cold at a same speed
But to 10 DEG C, 10min is stood；
Directly it is reduced to 10 DEG C to compare from 50 DEG C with the speed of 2 DEG C/h compared to comparative example 1, this comparative example forms one
The cooling of kind gradient type, weighs to the p-phenylenediamine obtained in this comparative example, the weight for obtaining p-phenylenediamine is
1.03364kg, then yield is 95.71%, and by chromatographic, the purity of the p-phenylenediamine of acquisition is 96.21%；
Although can be seen that the present embodiment uses the cooling of gradient type, it is the absence of circulation, is not redissolved, yield will be lower than
Embodiment 1 measures the partial size of the crystal of the p-phenylenediamine of acquisition, is measured its particle size range substantially in 0.8mm-
Between 1.8mm, endpoint value and span are all larger than embodiment 1, and the uniformity is less than embodiment 1.
Comparative example 4:
On the basis of embodiment 1, other are constant, and the speed slowly to heat up is modified as being rapidly heated, heating rate
For 2 DEG C/min；I.e. in this comparative example, although using repeated multiple times heating temperature-fall period same as Example 1,
This comparative example is all made of quick heating and cooling, and the clear weight of final p-phenylenediamine is 1.07558kg, then its yield is slightly below
Embodiment 1 simultaneously can be approximately considered same as Example 1, therefore can approximately think influence to yield and little；Pass through gas
The purity of chromatograph, the p-phenylenediamine of acquisition is also very nearly the same；But the present embodiment makes using being rapidly heated
It obtains partially crystallizable to fail to be completely dissolved, the partial size of the crystal of the p-phenylenediamine of acquisition is measured, its particle size range is measured
Substantially between 0.6mm-1.5mm, the uniformity is less than embodiment 1.
The application, so that p-phenylenediamine generates multiple recrystallization, improves its purity, together using repeatedly heating cooling
When crystallization of the solution containing the p-phenylenediamine of some in each recrystallization, and then provide induction for crystallization next time
Effect, promotes the crystallization of p-phenylenediamine, also with the quick alternating to cool down and slowly heat up, on the one hand in cooling
Accelerating the speed that crystallization is precipitated ensure that the uniformity of crystalline solid avoids slow cooling from generating coarse crystal grain, at the same with it is slow
Slow heating combines, so that crystal is slowly dissolved, further ensure that the uniformity of crystal grain, generates a kind of dynamic and ties again
Crystalline substance adjustment, forms more uniform crystal.
Obviously, various changes and modifications can be made to the invention without departing from of the invention by those skilled in the art
Spirit and scope.In this way, if these modifications and changes of the present invention belongs to the model of the claims in the present invention and its equivalent technologies
Within enclosing, then the present invention is also intended to include these modifications and variations.
Claims (5)
1. a kind of preparation process of p-phenylenediamine, which is characterized in that the p-phenylenediamine using paranitroanilinum and hydrogen as raw material,
Using methanol as solvent, reduction reaction is carried out using Raney Ni catalyst, p-phenylenediamine crystal grain is added into the solution after reaction
As crystal seed, crystallization is carried out by repeated multiple times heating, cooling process, separation crystal is drying to obtain the p-phenylenediamine.
2. a kind of preparation process of p-phenylenediamine as described in claim 1, which is characterized in that the repeated multiple times heating,
Temperature-fall period is as follows:
(1) be added p-phenylenediamine crystal grain after, stir evenly, be then lifted out the temperature of reaction kettle to 64 DEG C, formed saturation to benzene
Diamines methanol solution, is then rapidly cooled to 50 DEG C for solution temperature, and the crystal and standing of a part of p-phenylenediamine are precipitated again
Then 10min is rapidly cooled to 30 DEG C to solution, stand 0.5 hour；Temperature of reaction kettle is then to slowly warm up to 60 DEG C；
(2) temperature of reaction kettle is then rapidly cooled to 20 DEG C, stands 0.5 hour, then temperature of reaction kettle is to slowly warm up to 50
DEG C, 0.5 hour is stood, solution is then rapidly cooled to 20 DEG C；
(3) when solution is cooled to 20 DEG C, 0.5h is stood, and promote the mixing speed of reaction kettle, then cools down solution rapidly
To 10 DEG C, 0.5 hour is stood.
3. a kind of preparation process of p-phenylenediamine as claimed in claim 2, which is characterized in that specifically comprise the following steps:
Step 1: paranitroanilinum, methanol and Raney Ni catalyst are put into reaction kettle, wherein paranitroanilinum and first
The mass ratio of alcoholic solvent is 1:15, and Raney Ni catalyst charge is the 3% of paranitroanilinum quality；Nitrogen is passed through to be set
It changes, displacement number is not less than 2 times；Hydrogen is then passed to, starts reaction kettle for temperature and rises to 50 DEG C, pressure rises to 2.5MPa, and
Its revolving speed is promoted to 1000rpm by the blender for starting reaction kettle simultaneously, is reacted, and the reaction time is not less than 1.5 hours；Instead
After answering, by the pressure pressure release of reaction kettle to normal pressure state, the temperature of reaction kettle is promoted to 64 DEG C, the revolving speed of reaction kettle is dropped
Down to 500rpm；
Step 2: and then p-phenylenediamine crystal grain is put into the solution of step 1 after reaction, until p-phenylenediamine is not redissolved,
The p-phenylenediamine methanol solution for forming saturation, stirs evenly, solution temperature is then rapidly cooled to 50 DEG C, and one is precipitated again
Divide the crystal of p-phenylenediamine and stand 10min, 30 DEG C then are rapidly cooled to solution, stands 0.5 hour；Then by reaction kettle
Temperature is to slowly warm up to 60 DEG C；
Step 3: the solution after step 2 is heated up is rapidly cooled to 20 DEG C, stands 0.5 hour, then delays temperature of reaction kettle
Slowly 50 DEG C are warming up to, 0.5 hour is stood, solution is then rapidly cooled to 20 DEG C；
Step 4: when solution is cooled to 20 DEG C, standing 0.5h, and the mixing speed for promoting reaction kettle then will to 800rpm
Solution is rapidly cooled to 10 DEG C, stands 0.5 hour；
Step 5: the p-phenylenediamine crystal that separating step four obtains, and be dried in vacuo, obtain p-phenylenediamine finished product.
4. a kind of preparation process of p-phenylenediamine as claimed in claim 3, which is characterized in that the cooling speed rapidly is
2 DEG C/min, the speed slowly to heat up is 30 DEG C/h.
5. a kind of preparation process of p-phenylenediamine as claimed in claim 4, which is characterized in that the vacuum drying temperature is
80℃。
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| CN113307738A (en) * | 2021-05-31 | 2021-08-27 | 江苏方圆芳纶研究院有限公司 | Novel recrystallization process of phenylenediamine |
| CN114349645A (en) * | 2020-10-13 | 2022-04-15 | 中石化南京化工研究院有限公司 | Method for purifying p-phenylenediamine and application thereof |
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| CN114349645A (en) * | 2020-10-13 | 2022-04-15 | 中石化南京化工研究院有限公司 | Method for purifying p-phenylenediamine and application thereof |
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