CN117229178A - Method for preparing clt acid by liquid phase baking method - Google Patents
Method for preparing clt acid by liquid phase baking method Download PDFInfo
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- CN117229178A CN117229178A CN202311274814.XA CN202311274814A CN117229178A CN 117229178 A CN117229178 A CN 117229178A CN 202311274814 A CN202311274814 A CN 202311274814A CN 117229178 A CN117229178 A CN 117229178A
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- 238000000034 method Methods 0.000 title claims abstract description 113
- 239000002253 acid Substances 0.000 title claims abstract description 84
- 239000007791 liquid phase Substances 0.000 title claims abstract description 24
- 239000000376 reactant Substances 0.000 claims abstract description 115
- 230000018044 dehydration Effects 0.000 claims abstract description 82
- 238000006297 dehydration reaction Methods 0.000 claims abstract description 82
- 238000006243 chemical reaction Methods 0.000 claims abstract description 68
- 230000008569 process Effects 0.000 claims abstract description 62
- QAOWNCQODCNURD-UHFFFAOYSA-N sulfuric acid Substances OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 claims abstract description 52
- HIHCTGNZNHSZPP-UHFFFAOYSA-N 4-chloro-3-methylaniline Chemical compound CC1=CC(N)=CC=C1Cl HIHCTGNZNHSZPP-UHFFFAOYSA-N 0.000 claims abstract description 43
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- RFFLAFLAYFXFSW-UHFFFAOYSA-N 1,2-dichlorobenzene Chemical compound ClC1=CC=CC=C1Cl RFFLAFLAYFXFSW-UHFFFAOYSA-N 0.000 claims description 104
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 78
- 238000004321 preservation Methods 0.000 claims description 54
- 239000012071 phase Substances 0.000 claims description 34
- 238000001514 detection method Methods 0.000 claims description 19
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- 230000005945 translocation Effects 0.000 claims description 10
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- 125000002924 primary amino group Chemical group [H]N([H])* 0.000 claims description 7
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- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 abstract description 26
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- 229910052742 iron Inorganic materials 0.000 abstract description 12
- YXFVVABEGXRONW-UHFFFAOYSA-N Toluene Chemical compound CC1=CC=CC=C1 YXFVVABEGXRONW-UHFFFAOYSA-N 0.000 abstract description 9
- 230000015572 biosynthetic process Effects 0.000 abstract description 7
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- 238000004519 manufacturing process Methods 0.000 description 12
- 238000012546 transfer Methods 0.000 description 9
- BDHFUVZGWQCTTF-UHFFFAOYSA-M sulfonate Chemical compound [O-]S(=O)=O BDHFUVZGWQCTTF-UHFFFAOYSA-M 0.000 description 6
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- VYZCFAPUHSSYCC-UHFFFAOYSA-N 2-amino-5-chloro-4-methylbenzenesulfonic acid Chemical compound CC1=CC(N)=C(S(O)(=O)=O)C=C1Cl VYZCFAPUHSSYCC-UHFFFAOYSA-N 0.000 description 1
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- Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
Abstract
The invention relates to the technical field of clt acid preparation, in particular to a method for preparing clt acid by a liquid phase baking method. Comprising the following steps: adding concentrated sulfuric acid into a mixture comprising 4-chloro-3-methylaniline and a dispersion solvent to obtain a reaction material; the reaction material is subjected to a salification process to generate a reactant; the reactant comprises a sulfonate salt; the reactants were dehydrated to form clt acid by the metathesis process. In the prior art, clt acid is generated by adopting a toluene sulfonation method, and the clt acid can be synthesized, but a large amount of waste iron mud and waste water are generated in the synthesis process, so that the pollution to the environment is large. Compared with the prior art, the method adopts 4-chloro-3-methylaniline as a raw material and synthesizes the needed clt acid through the processes of salification and dehydration. In the synthesis process, iron powder is not required to be used as a catalyst, and waste iron mud is not generated. Meanwhile, the total amount of wastewater generated in the dehydration process is relatively less, and the wastewater amount is effectively reduced.
Description
Technical Field
The invention relates to the technical field of clt acid preparation, in particular to a method for preparing clt acid by a liquid phase baking method.
Background
clt acid, the chemical name of which is 2 amino 4 methyl 5 chlorobenzene sulfonic acid, is an important red organic pigment intermediate, and is mainly used for manufacturing organic pigments such as golden red C, rubber scarlet LG, and Lixol scarlet. Meanwhile, clt acid is also widely used for the preparation of inks, paints, coatings and the coloration of plastics and rubber.
The current synthesis method of clt acid is toluene sulfonation, namely toluene is subjected to sulfonation, chlorination, nitration, reduction, acid precipitation, pressure filtration and drying to obtain clt acid finished products. Although the foregoing process is effective in synthesizing clt acid, iron powder is required as a catalyst in the reduction step, which results in the foregoing synthesis process producing a large amount of iron sludge, which is subsequently extracted to yield clt acid. In addition, a small amount of iron ions remain in clt acid. Although there is a synthetic method in which iron powder is replaced with a noble metal catalyst, there are problems such as dechlorination, desulfonation groups, and catalyst loss. On the other hand, the aforementioned acid precipitation process generates a large amount of wastewater. According to measurement and calculation, 20-30 tons of waste water and about 1 ton of waste iron mud are produced for each 1 ton of clt acid production. This can cause serious environmental pollution.
Disclosure of Invention
Aiming at the technical problems in the prior art, the invention provides a method for preparing clt acid by a liquid-phase baking method.
In order to solve the technical problems, the invention provides the following technical scheme:
a method of preparing clt acid by liquid phase baking comprising: adding concentrated sulfuric acid into a mixture comprising 4-chloro-3-methylaniline and a dispersion solvent to obtain a reaction material; the reaction material is subjected to a salification process to generate a reactant; reactants include sulfonates; the salt forming process is as follows:
；
dehydrating the reactant to separate water from the reactant and performing a translocation process to produce clt acid;
the indexing process is as follows:
。
in actual operation, the invention adopts 4-chloro-3-methylaniline as a raw material. The sulfonate is produced by mixing 4-chloro-3-methylaniline, a dispersion solvent and concentrated sulfuric acid for a salt formation process. In this case, concentrated sulfuric acid is mixed with a small amount of water due to purity problems. The water does not participate in the salt formation process but eventually mixes with the sulfonate salt. Subsequently, a dehydration process is performed to remove one molecule of water from one molecule of sulfonate, so that the sulfonate undergoes a translocation process to produce the desired clt acid. Therefore, in the synthesis process of the invention, iron powder is not required to be added as a catalyst, so that a large amount of waste iron sludge is not generated. On the other hand, the wastewater produced by the invention comprises water obtained by mixing concentrated sulfuric acid and water obtained by removing sulfonate, and the total amount of the water is relatively small, so that the wastewater production is effectively reduced. In conclusion, the invention provides a novel clt acid synthesis path, which can effectively reduce the generation of pollutants and reduce the pollution to the environment on the premise of effectively obtaining clt acid.
Further, the method also comprises a material mixing step; the "material mixing step" includes the steps of: placing 4-chloro-3-methylaniline and a dispersion solvent into a reaction kettle, and uniformly stirring to obtain a mixture; pumping the mixture into a high-level tank; heating the mixture to a heat preservation temperature and carrying out heat preservation.
Further, the mass ratio of the 4-chloro-3-methylaniline to the dispersing solvent is 0.16-2.
Further, the method also comprises a salt forming step; the "salifying step" comprises the steps of: adding concentrated sulfuric acid into the mixture to obtain a reaction material; pumping the reaction material into a dynamic tubular reactor; heating the reaction material to a reaction temperature; the reaction mass is subjected to a salification process to produce the reactants.
Further, the molar ratio of the 4-chloro-3-methylaniline to the concentrated sulfuric acid is 1:1.
Further, a 'pre-dewatering step' is also included; the "pre-dewatering step" includes the steps of: continuously transferring reactants into a heat preservation kettle; the reaction was stirred and heated to a pre-dehydration temperature.
Further, the pre-dehydration temperature is 120-135 ℃.
Further, the "pre-dewatering step" further comprises the steps of: collecting gas phase separated by the heat preservation kettle, wherein the gas phase separated by the heat preservation kettle comprises a dispersion solvent and water; introducing the gas phase separated by the heat-preserving kettle into a water separator to obtain the dispersion solvent; transferring the dispersion solvent into a heat preservation kettle.
Further, a "dehydration step" is included; the "dehydration step" further includes the steps of: transferring the reactant into a baking kettle; heating the reactant in the baking kettle to a dehydration temperature; the dehydration temperature is maintained for a specified period of time to conduct the indexing process.
Further, the dehydration temperature is 170-195 ℃.
Further, the "dehydration step" further includes the steps of: collecting gas phase separated by a baking kettle, wherein the gas phase separated by the baking kettle comprises a dispersion solvent and water; introducing the gas phase separated by the baking kettle into a water separator to obtain a dispersion solvent; the dispersion solvent was collected.
Further, a detection step is included; the "detection step" includes the steps of: detecting clt acid; when the detection is qualified, carrying out vacuum baking and drying treatment on clt acid; and cooling and collecting clt acid when the amino value is more than or equal to 98 percent.
Further, o-dichlorobenzene was used as the dispersion solvent.
Compared with the prior art, the invention has the following advantages:
the method of the invention effectively improves the purity of clt acid and effectively reduces the content of residual iron ions.
When the invention is actually executed, a plurality of steps can be synchronously carried out, thereby effectively shortening the time required by the whole process.
The invention has no waste iron mud output and effectively reduces the output of waste water, thereby reducing environmental pollution.
Meanwhile, according to the process, a reasonable temperature rising gradient is set, so that the heating temperature in the previous step is effectively utilized, and the energy consumption is effectively reduced. On the other hand, the phenomenon of carbonization caused by overlarge temperature span is also effectively avoided.
According to the invention, the o-dichlorobenzene plays a role in providing a required chemical environment by virtue of a solvent and also plays a role in uniformly transferring heat. And the water can be azeotroped at a specific temperature, so that the water and the water are jointly separated in a gas phase state, on one hand, no additional purification step is required for clt acid, and the production link is simplified. On the other hand, the o-dichlorobenzene can also play a role in promoting the progress of the translocation process.
Drawings
Fig. 1: an overall flow chart.
Detailed Description
The following are specific embodiments of the present invention and the technical solutions of the present invention will be further described with reference to the accompanying drawings, but the present invention is not limited to these embodiments.
Embodiment one:
a method of preparing clt acid by liquid phase baking comprising: the method comprises a material mixing step, a salifying step, a pre-dewatering step, a dewatering step and a detection step. Specifically, the material mixing step includes the following steps: the mass ratio of the 4-chloro-3-methylaniline to the dispersing solvent is 0.16-2. In this example, the mass ratio between 4-chloro-3-methylaniline and the dispersion solvent was 0.7, and 700kg of 4-chloro-3-methylaniline having a content of 99.6% and 1000kg of the dispersion solvent were mixed and put into a reaction vessel and stirred uniformly to obtain a mixture. Wherein, the dispersion solvent adopts o-dichlorobenzene. Pumping the mixture into a high-level tank, heating the mixture to a heat preservation temperature and preserving heat. The incubation temperature was 70 ℃.
The salifying step comprises the following steps:
998kg of 98% concentrated sulfuric acid is pumped into a high-level tank from a storage tank according to the mol ratio of the 4-chloro-3-methylaniline to the concentrated sulfuric acid of 1:1 so as to be mixed with the mixture to obtain a reaction material. Wherein, under the influence of purity, a small amount of water is mixed in the concentrated sulfuric acid. The reaction mass was pumped into the dynamic tube reactor by means of a metering pump. The flow rate of the mixture is 680kg/h, and the flow rate of the sulfuric acid is 400kg/h. The reaction materials are heated to the reaction temperature of 95 ℃, and the reaction temperature is controlled by cooling circulating water, so that the reaction temperature can be stably maintained. In the present state, concentrated sulfuric acid can be subjected to a salification process with 4-chloro-3-methylaniline to produce the reactant. The reactants include sulfonates. The water mixed in the concentrated sulfuric acid does not participate in the reaction, but is eventually mixed with the sulfonate. The salt forming process is specifically as follows:
。
wherein, the o-dichlorobenzene is very stable. In the present environment, it does not react with 4-chloro-3-methylaniline, concentrated sulfuric acid or a combination of the two, nor with the reactants. Only serves as a reaction environment for the aforementioned salification process and serves to uniformly transfer heat upon heating.
Meanwhile, the molar ratio of the 4-chloro-3-methylaniline to the concentrated sulfuric acid enables the 4-chloro-3-methylaniline and the concentrated sulfuric acid to react completely, so that the 4-chloro-3-methylaniline or the concentrated sulfuric acid has no residue.
The pre-dewatering step comprises the steps of:
in the salification step, the salification process is very rapid. That is, the process of mixing 4-chloro-3-methylaniline with concentrated sulfuric acid to form a salt starts under the aforementioned circumstances. Therefore, when the concentrated sulfuric acid is added, the reactant can be transferred into the heat preservation kettle, rather than transferring the reactant into the heat preservation kettle after the 4-chloro-3-methylaniline and the concentrated sulfuric acid completely react, so that the time required by the whole preparation process is effectively shortened. After the reactants are transferred into the heat preservation kettle, stirring the reactants and heating the reactants to a pre-dehydration temperature, wherein the pre-dehydration temperature is as follows: 120-135 ℃. The pre-dewatering temperature in this example was 130 ℃. After the reactant enters the heat preservation kettle, a small amount of residual 4-chloro-3-methylaniline and concentrated sulfuric acid continue to react. Up to this point, the amount of unreacted 4-chloro-3-methylaniline and concentrated sulfuric acid was very small and negligible. Meanwhile, the reactant is initially dehydrated at the pre-dehydration temperature. At this time, a small amount of water was separated from the autoclave in the form of a gas phase together with a small amount of o-dichlorobenzene. And collecting the gas phase separated by the heat preservation kettle, condensing, and introducing the condensed liquid mixture into a water separator to separate water from o-dichlorobenzene. The separated o-dichlorobenzene is reintroduced into the thermal insulation kettle to maintain the chemical environment in the thermal insulation kettle. The separated water is treated as wastewater. And as the reactants continuously enter the heat preservation kettle, the volume of the reactants in the heat preservation kettle is gradually increased, and when the volume of the reactants reaches the designated volume, the reactants are transferred into the baking kettle so as to carry out the dehydration step. Wherein the designated volume is two thirds of the volume of the heat preservation kettle.
It is noted that the pre-dehydration step may not be performed, and the reactant may be directly transferred into the baking kettle to perform the dehydration step.
The dehydration step comprises the following steps:
and after the reactant enters the baking kettle, the reactant is continuously heated until the temperature reaches the dehydration temperature. The dehydration temperature is 170-195 ℃. The dehydration temperature in this example was 185 ℃. After the dehydration temperature was reached, the temperature in the baking oven was maintained above and below 185 ℃ by baking oven heat transfer oil. At the present temperature, o-dichlorobenzene azeotropes with water, beginning to co-evolve from the baking kettle in the vapor phase. The reactants begin the dehydration process and the translocation process. The indexing process is as follows:
。
thus, the target product clt acid was produced. Meanwhile, the gas phase separated by the baking kettle is condensed and then transferred into a water separator, and the temperature of the gas phase at the outlet of the water separator is controlled to be 96 ℃. Thereby, o-dichlorobenzene is separated from water. The separated o-dichlorobenzene is reintroduced into the baking kettle. The separated water is treated as wastewater. The dehydration temperature is maintained for a specified period of time. The method comprises the following steps: when the foregoing process was maintained for 6 hours and after 6 hours had been reached, the water contained in the reaction mass had been reduced to a certain proportion, the weather temperature at the outlet of the water separator was controlled to 105 ℃. And maintaining for 5 hours, wherein after 5 hours, the reactant is basically converted into clt acid, detecting the reactant according to national standards, and vacuumizing a baking kettle if the detection is qualified, so as to perform vacuum baking and drying treatment on the reactant. The vacuum should be greater than-0.092 mpa and the temperature is controlled to 175 c by baking the kettle heat transfer oil. The vacuum baking and drying are maintained for 2.5 hours. Thereby maximizing conversion of the reactant to clt acid. After reaching 2.5h, sampling detection was performed again. If the amino value is more than or equal to 98%, the product is qualified, and clt acid is cooled and collected.
On the other hand, when the dehydration temperature is maintained for a time period close to the specified time period, preferably, when the dehydration temperature is maintained for 10 hours, the separated o-dichlorobenzene is not introduced into the baking vessel any more but is collected for the next round of clt acid production. Therefore, the stable and heat-conducting characteristics of the o-dichlorobenzene are utilized to the greatest extent, so that reactants can be heated uniformly in the conversion process.
Embodiment two:
a method of preparing clt acid by liquid phase baking comprising: the method comprises a material mixing step, a salifying step, a pre-dewatering step, a dewatering step and a detection step. Specifically, the material mixing step includes the following steps: in the embodiment, the mass ratio between the 4-chloro-3-methylaniline and the o-dichlorobenzene is 0.43, 700kg of the 4-chloro-3-methylaniline with the content of 99.6 percent and 1600kg of the o-dichlorobenzene are taken and mixed into a reaction kettle, and the mixture is obtained by stirring uniformly. Pumping the mixture into a high-level tank, heating the mixture to a heat preservation temperature and preserving heat. The incubation temperature was 70 ℃.
The salifying step comprises the following steps:
998kg of 98% concentrated sulfuric acid is pumped into a high-level tank from a storage tank according to the mol ratio of the 4-chloro-3-methylaniline to the concentrated sulfuric acid of 1:1 so as to be mixed with the mixture to obtain a reaction material. The reaction mass was pumped into the dynamic tube reactor by means of a metering pump. The flow rate of the mixture is 920kg/h, and the flow rate of the sulfuric acid is 400kg/h. The reaction materials are heated to the reaction temperature of 95 ℃, and the reaction temperature is controlled by cooling circulating water, so that the reaction temperature can be stably maintained. In the present state, concentrated sulfuric acid can be subjected to a salification process with 4-chloro-3-methylaniline to produce the reactant.
The pre-dewatering step comprises the steps of:
and (3) adding concentrated sulfuric acid, transferring the reactant into a heat preservation kettle, and stirring the reactant and heating the reactant to a pre-dehydration temperature after transferring the reactant into the heat preservation kettle. The pre-dewatering temperature in this example was 130 ℃. At the pre-dehydration temperature, the reactants undergo a preliminary dehydration process. At this time, a small amount of water was separated from the autoclave in the form of a gas phase together with a small amount of o-dichlorobenzene. And collecting the gas phase separated by the heat preservation kettle, condensing, and introducing the condensed liquid mixture into a water separator to separate water from o-dichlorobenzene. The separated o-dichlorobenzene is reintroduced into the heat preservation kettle, and the separated water is treated as wastewater. The volume of the reactant in the heat preservation kettle is gradually increased along with the continuous entering of the reactant in the heat preservation kettle, and when the volume of the reactant reaches two thirds of the volume of the heat preservation kettle, the reactant is transferred into the baking kettle to carry out the dehydration step.
The dehydration step comprises the following steps:
and after the reactant enters the baking kettle, the reactant is continuously heated until the temperature reaches the dehydration temperature. The dehydration temperature in this example was 180 ℃. When the dehydration temperature is reached, the temperature in the baking kettle is maintained to be above or below 180 ℃ through the heat conducting oil of the baking kettle. At the present temperature, o-dichlorobenzene azeotropes with water, beginning to co-evolve from the baking kettle in the vapor phase. The reactants begin the dehydration process and the translocation process.
Thus, the target product clt acid was produced. Meanwhile, the gas phase separated by the baking kettle is condensed and then transferred into a water separator, and the temperature of the gas phase at the outlet of the water separator is controlled to be 96 ℃. Thereby, o-dichlorobenzene is separated from water. The separated o-dichlorobenzene is reintroduced into the baking kettle. The separated water is treated as wastewater. The dehydration temperature is maintained for a specified period of time. The method comprises the following steps: the foregoing process was maintained for 6 hours, and after reaching 6 hours, the diverter outlet weather temperature was controlled to 105 ℃. And maintaining for 5 hours, wherein after 5 hours, the reactant is basically converted into clt acid, detecting the reactant according to national standards, and vacuumizing a baking kettle if the detection is qualified, so as to perform vacuum baking and drying treatment on the reactant. The vacuum should be greater than-0.092 mpa and the temperature is controlled to 175 c by baking the kettle heat transfer oil. The vacuum baking and drying are maintained for 2.5 hours. Thereby maximizing conversion of the reactant to clt acid. After reaching 2.5h, sampling detection was performed again. If the amino value is more than or equal to 98%, the product is qualified, and clt acid is cooled and collected.
On the other hand, when the dehydration temperature is maintained for a time period close to the specified time period, preferably, when the dehydration temperature is maintained for 10 hours, the separated o-dichlorobenzene is not introduced into the baking vessel any more but is collected for the next round of clt acid production.
Embodiment III:
a method of preparing clt acid by liquid phase baking comprising: the method comprises a material mixing step, a salifying step, a pre-dewatering step, a dewatering step and a detection step. Specifically, the material mixing step includes the following steps: in the embodiment, the mass ratio between the 4-chloro-3-methylaniline and the o-dichlorobenzene is 0.43, 700kg of the 4-chloro-3-methylaniline with the content of 99.6 percent and 1600kg of the o-dichlorobenzene are taken and mixed into a reaction kettle, and the mixture is obtained by stirring uniformly. Pumping the mixture into a high-level tank, heating the mixture to a heat preservation temperature and preserving heat. The incubation temperature was 70 ℃.
The salifying step comprises the following steps:
998kg of 98% concentrated sulfuric acid is pumped into a high-level tank from a storage tank according to the mol ratio of the 4-chloro-3-methylaniline to the concentrated sulfuric acid of 1:1 so as to be mixed with the mixture to obtain a reaction material. The reaction mass was pumped into the dynamic tube reactor by means of a metering pump. The flow rate of the mixture is 920kg/h, and the flow rate of the sulfuric acid is 400kg/h. The reaction materials are heated to the reaction temperature of 95 ℃, and the reaction temperature is controlled by cooling circulating water, so that the reaction temperature can be stably maintained. In the present state, concentrated sulfuric acid can be subjected to a salification process with 4-chloro-3-methylaniline to produce the reactant.
The pre-dewatering step comprises the steps of:
and (3) adding concentrated sulfuric acid, transferring the reactant into a heat preservation kettle, and stirring the reactant and heating the reactant to a pre-dehydration temperature after transferring the reactant into the heat preservation kettle. The pre-dewatering temperature in this example was 130 ℃. At the pre-dehydration temperature, the reactants undergo a preliminary dehydration process. At this time, a small amount of water was separated from the autoclave in the form of a gas phase together with a small amount of o-dichlorobenzene. And collecting the gas phase separated by the heat preservation kettle, condensing, and introducing the condensed liquid mixture into a water separator to separate water from o-dichlorobenzene. The separated o-dichlorobenzene is reintroduced into the heat preservation kettle, and the separated water is treated as wastewater. The volume of the reactant in the heat preservation kettle is gradually increased along with the continuous entering of the reactant in the heat preservation kettle, and when the volume of the reactant reaches two thirds of the volume of the heat preservation kettle, the reactant is transferred into the baking kettle to carry out the dehydration step.
The dehydration step comprises the following steps:
and after the reactant enters the baking kettle, the reactant is continuously heated until the temperature reaches the dehydration temperature. The dehydration temperature in this example was 185 ℃. After the dehydration temperature was reached, the temperature in the baking oven was maintained above and below 185 ℃ by baking oven heat transfer oil. At the present temperature, o-dichlorobenzene azeotropes with water, beginning to co-evolve from the baking kettle in the vapor phase. The reactants begin the dehydration process and the translocation process.
Thus, the target product clt acid was produced. Meanwhile, the gas phase separated by the baking kettle is condensed and then transferred into a water separator, and the temperature of the gas phase at the outlet of the water separator is controlled to be 96 ℃. Thereby, o-dichlorobenzene is separated from water. The separated o-dichlorobenzene is reintroduced into the baking kettle. The separated water is treated as wastewater. The dehydration temperature is maintained for a specified period of time. The method comprises the following steps: the foregoing procedure was maintained for 5 hours, and after 5 hours had been reached, the diverter outlet weather temperature was controlled to 105 ℃. And maintaining for 4 hours, wherein after 4 hours, the reactant is basically converted into clt acid, detecting the reactant according to national standards, and vacuumizing a baking kettle if the detection is qualified, so as to perform vacuum baking and drying treatment on the reactant. The vacuum should be greater than-0.092 mpa and the temperature is controlled to 175 c by baking the kettle heat transfer oil. The vacuum baking and drying are maintained for 2.5 hours. Thereby maximizing conversion of the reactant to clt acid. After reaching 2.5h, sampling detection was performed again. If the amino value is more than or equal to 98%, the product is qualified, and clt acid is cooled and collected.
On the other hand, when the dehydration temperature is maintained for a time period close to the specified time period, preferably, when the dehydration temperature is maintained for 10 hours, the separated o-dichlorobenzene is not introduced into the baking vessel any more but is collected for the next round of clt acid production.
Embodiment four:
a method of preparing clt acid by liquid phase baking comprising: the method comprises a material mixing step, a salifying step, a pre-dewatering step, a dewatering step and a detection step. Specifically, the material mixing step includes the following steps: in the embodiment, the mass ratio between the 4-chloro-3-methylaniline and the o-dichlorobenzene is 0.43, 700kg of the 4-chloro-3-methylaniline with the content of 99.6 percent and 1600kg of the o-dichlorobenzene are taken and mixed into a reaction kettle, and the mixture is obtained by stirring uniformly. Pumping the mixture into a high-level tank, heating the mixture to a heat preservation temperature and preserving heat. The incubation temperature was 70 ℃.
The salifying step comprises the following steps:
998kg of 98% concentrated sulfuric acid is pumped into a high-level tank from a storage tank according to the mol ratio of the 4-chloro-3-methylaniline to the concentrated sulfuric acid of 1:1 so as to be mixed with the mixture to obtain a reaction material. The reaction mass was pumped into the dynamic tube reactor by means of a metering pump. The flow rate of the mixture is 920kg/h, and the flow rate of the sulfuric acid is 400kg/h. The reaction materials are heated to the reaction temperature of 95 ℃, and the reaction temperature is controlled by cooling circulating water, so that the reaction temperature can be stably maintained. In the present state, concentrated sulfuric acid can be subjected to a salification process with 4-chloro-3-methylaniline to produce the reactant.
The pre-dewatering step comprises the steps of:
and (3) adding concentrated sulfuric acid, transferring the reactant into a heat preservation kettle, and stirring the reactant and heating the reactant to a pre-dehydration temperature after transferring the reactant into the heat preservation kettle. The pre-dewatering temperature in this example was 130 ℃. At the pre-dehydration temperature, the reactants undergo a preliminary dehydration process. At this time, a small amount of water was separated from the autoclave in the form of a gas phase together with a small amount of o-dichlorobenzene. And collecting the gas phase separated by the heat preservation kettle, condensing, and introducing the condensed liquid mixture into a water separator to separate water from o-dichlorobenzene. The separated o-dichlorobenzene is reintroduced into the heat preservation kettle, and the separated water is treated as wastewater. The volume of the reactant in the heat preservation kettle is gradually increased along with the continuous entering of the reactant in the heat preservation kettle, and when the volume of the reactant reaches two thirds of the volume of the heat preservation kettle, the reactant is transferred into the baking kettle to carry out the dehydration step.
The dehydration step comprises the following steps:
and after the reactant enters the baking kettle, the reactant is continuously heated until the temperature reaches the dehydration temperature. The dehydration temperature in this example was 185 ℃. After the dehydration temperature was reached, the temperature in the baking oven was maintained above and below 185 ℃ by baking oven heat transfer oil. At the present temperature, o-dichlorobenzene azeotropes with water, beginning to co-evolve from the baking kettle in the vapor phase. The reactants begin the dehydration process and the translocation process.
Thus, the target product clt acid was produced. Meanwhile, the gas phase separated by the baking kettle is condensed and then transferred into a water separator, and the temperature of the gas phase at the outlet of the water separator is controlled to be 96 ℃. Thereby, o-dichlorobenzene is separated from water. The separated o-dichlorobenzene is reintroduced into the baking kettle. The separated water is treated as wastewater. The dehydration temperature is maintained for a specified period of time. The method comprises the following steps: the foregoing process was maintained for 6 hours, and after reaching 6 hours, the diverter outlet weather temperature was controlled to 105 ℃. And maintaining for 5 hours, wherein after 5 hours, the reactant is basically converted into clt acid, detecting the reactant according to national standards, and vacuumizing a baking kettle if the detection is qualified, so as to perform vacuum baking and drying treatment on the reactant. The vacuum degree should be greater than-0.092 mpa, and the temperature is controlled at 180 ℃ by baking kettle conduction oil. The vacuum baking and drying are maintained for 1.5 hours. Thereby maximizing conversion of the reactant to clt acid. After reaching 2.5h, sampling detection was performed again. If the amino value is more than or equal to 98%, the product is qualified, and clt acid is cooled and collected.
On the other hand, when the dehydration temperature is maintained for a time period close to the specified time period, preferably, when the dehydration temperature is maintained for 10 hours, the separated o-dichlorobenzene is not introduced into the baking vessel any more but is collected for the next round of clt acid production.
Fifth embodiment:
a method of preparing clt acid by liquid phase baking comprising: the method comprises a material mixing step, a salifying step, a pre-dewatering step, a dewatering step and a detection step. Specifically, the material mixing step includes the following steps: in the embodiment, the mass ratio between the 4-chloro-3-methylaniline and the o-dichlorobenzene is 0.43, 700kg of the 4-chloro-3-methylaniline with the content of 99.6 percent and 1600kg of the o-dichlorobenzene are taken and mixed into a reaction kettle, and the mixture is obtained by stirring uniformly. Pumping the mixture into a high-level tank, heating the mixture to a heat preservation temperature and preserving heat. The incubation temperature was 70 ℃.
The salifying step comprises the following steps:
998kg of 98% concentrated sulfuric acid is pumped into a high-level tank from a storage tank according to the mol ratio of the 4-chloro-3-methylaniline to the concentrated sulfuric acid of 1:1 so as to be mixed with the mixture to obtain a reaction material. The reaction mass was pumped into the dynamic tube reactor by means of a metering pump. The flow rate of the mixture is 920kg/h, and the flow rate of the sulfuric acid is 400kg/h. The reaction materials are heated to the reaction temperature of 95 ℃, and the reaction temperature is controlled by cooling circulating water, so that the reaction temperature can be stably maintained. In the present state, concentrated sulfuric acid can be subjected to a salification process with 4-chloro-3-methylaniline to produce the reactant.
The pre-dewatering step comprises the steps of:
and (3) adding concentrated sulfuric acid, transferring the reactant into a heat preservation kettle, and stirring the reactant and heating the reactant to a pre-dehydration temperature after transferring the reactant into the heat preservation kettle. The pre-dewatering temperature in this example was 130 ℃. At the pre-dehydration temperature, the reactants undergo a preliminary dehydration process. At this time, a small amount of water was separated from the autoclave in the form of a gas phase together with a small amount of o-dichlorobenzene. And collecting the gas phase separated by the heat preservation kettle, condensing, and introducing the condensed liquid mixture into a water separator to separate water from o-dichlorobenzene. The separated o-dichlorobenzene is reintroduced into the heat preservation kettle, and the separated water is treated as wastewater. The volume of the reactant in the heat preservation kettle is gradually increased along with the continuous entering of the reactant in the heat preservation kettle, and when the volume of the reactant reaches two thirds of the volume of the heat preservation kettle, the reactant is transferred into the baking kettle to carry out the dehydration step.
The dehydration step comprises the following steps:
and after the reactant enters the baking kettle, the reactant is continuously heated until the temperature reaches the dehydration temperature. The dehydration temperature in this example was 185 ℃. After the dehydration temperature was reached, the temperature in the baking oven was maintained above and below 185 ℃ by baking oven heat transfer oil. At the present temperature, o-dichlorobenzene azeotropes with water, beginning to co-evolve from the baking kettle in the vapor phase. The reactants begin the dehydration process and the translocation process.
Thus, the target product clt acid was produced. Meanwhile, the gas phase separated by the baking kettle is condensed and then transferred into a water separator, and the temperature of the gas phase at the outlet of the water separator is controlled to be 96 ℃. Thereby, o-dichlorobenzene is separated from water. The separated o-dichlorobenzene is reintroduced into the baking kettle. The separated water is treated as wastewater. The dehydration temperature is maintained for a specified period of time. The method comprises the following steps: the foregoing process was maintained for 6 hours, and after reaching 6 hours, the diverter outlet weather temperature was controlled to 105 ℃. And maintaining for 5 hours, wherein after 5 hours, the reactant is basically converted into clt acid, detecting the reactant according to national standards, and vacuumizing a baking kettle if the detection is qualified, so as to perform vacuum baking and drying treatment on the reactant. The vacuum should be greater than-0.092 mpa and the temperature is controlled to 175 c by baking the kettle heat transfer oil. The vacuum baking and drying are maintained for 2.5 hours. Thereby maximizing conversion of the reactant to clt acid. After reaching 2.5h, sampling detection was performed again. If the amino value is more than or equal to 98%, the product is qualified, and clt acid is cooled and collected. The obtained clt acid is refined by the steps of alkali dissolution, acid precipitation, decoloration and drying, so as to obtain refined clt acid.
On the other hand, when the dehydration temperature is maintained for a time period close to the specified time period, preferably, when the dehydration temperature is maintained for 10 hours, the separated o-dichlorobenzene is not introduced into the baking vessel any more but is collected for the next round of clt acid production.
The clt acid per unit weight obtained in examples one, two, three, four, five and the prior art were tested according to national standards and the performance data are as follows:
。
therefore, the method of the invention effectively improves the purity of clt acid, effectively reduces the content of residual iron ions, and has the content of 0.17% at the minimum although 4-chloro-3-methylaniline is remained, so that the method can be ignored. The invention does not introduce iron powder as a catalyst, and residual iron ions mainly originate from corrosion of concentrated sulfuric acid to reaction equipment.
Based on the generation mechanism, when the method is actually executed, a plurality of steps can be synchronously carried out, so that the time required by the whole process is effectively shortened.
On the other hand, the waste water mainly originates from a small amount of water contained in the concentrated sulfuric acid and a molecule of water separated from a molecule of sulfonate in the transposition process, and iron powder is not needed to be used as a catalyst, so that per 1 ton of clt acid is produced according to the method, 500kg of waste water is produced, and no waste iron mud is produced. In the prior art, each time 1 ton of clt acid is produced, 20-30 tons of waste water and about 1 ton of waste iron mud are produced. The invention can effectively reduce environmental pollution.
Meanwhile, according to the process, a reasonable temperature rising gradient is set, so that the heating temperature in the previous step is effectively utilized, and the energy consumption is effectively reduced. On the other hand, the phenomenon of carbonization caused by overlarge temperature span is also effectively avoided. Particularly, in the process from the heat preservation kettle to the baking kettle, the reactant is preheated through the heat preservation kettle, and then is heated through the baking kettle. If the reactant is directly transferred into the baking kettle, the temperature span is too large, and the time is also required for the reactant to enter the baking kettle, so that the reactant entering the baking kettle is easy to be carbonized.
Meanwhile, the o-dichlorobenzene plays a role in providing a required chemical environment by the action of a solvent and also plays a role in uniformly transferring heat. And the water can be azeotroped at a specific temperature, so that the water and the water are jointly separated in a gas phase state, on one hand, no additional purification step is required for clt acid, and the production link is simplified. On the other hand, the o-dichlorobenzene can also play a role in promoting the progress of the translocation process.
It is noted that the mass ratio of 4-chloro-3-methylaniline to the dispersion solvent spans a relatively large range, and that only a small range of values is used in the examples described above. This does not mean that values in other intervals are not feasible, but that values in other intervals are equally feasible, but merely approaching theoretical operation, the actual production significance is poor. Therefore, no actual production test is purposely done.
It should be noted that, in the present invention, the combination of the reactor and the reaction vessel is not limited to the combination of the tubular reactor and the reaction vessel, and various combinations of the micro-channel or the reaction vessel, the reaction vessel and the separation tower can be adopted, so that the combination changes are all within the scope of the present invention.
The specific embodiments described herein are offered by way of example only to illustrate the spirit of the invention. Those skilled in the art may make various modifications or additions to the described embodiments or substitutions thereof without departing from the spirit of the invention or exceeding the scope of the invention as defined in the accompanying claims.
Claims (13)
1. A method for preparing clt acid by a liquid phase baking method, which is characterized by comprising the following steps of: comprising the following steps: adding concentrated sulfuric acid into a mixture comprising 4-chloro-3-methylaniline and a dispersion solvent to obtain a reaction material;
the reaction material is subjected to a salification process to generate a reactant;
the reactant comprises a sulfonate salt;
the salification process is as follows:
；
dehydrating the reactant to separate water from the reactant and performing a translocation process to produce clt acid;
the indexing process is as follows:
。
2. a method for preparing clt acid by liquid phase baking according to claim 1, wherein: also comprises a material mixing step;
the material mixing step comprises the following steps:
placing the 4-chloro-3-methylaniline and the dispersion solvent into a reaction kettle and uniformly stirring to obtain the mixture;
pumping the mixture into an elevated tank;
heating the mixture to a heat preservation temperature and carrying out heat preservation.
3. A method for preparing clt acid by liquid phase baking according to claim 2, wherein: the mass ratio of the 4-chloro-3-methylaniline to the dispersion solvent is 0.16-2.
4. A method for preparing clt acid by liquid phase baking according to claim 1, wherein: also comprises a salt forming step;
the salt forming step comprises the following steps:
adding concentrated sulfuric acid into the mixture to obtain the reaction material;
pumping the reaction material into a dynamic tubular reactor;
heating the reaction material to a reaction temperature;
the reaction mass is subjected to the salification process to produce the reactant.
5. The method for preparing clt acid by liquid phase baking according to claim 4, wherein: the molar ratio of the 4-chloro-3-methylaniline to the concentrated sulfuric acid is 1:1.
6. A method for preparing clt acid by liquid phase baking according to claim 1, wherein: also includes a pre-dewatering step;
the "pre-dewatering step" comprises the steps of:
continuously transferring the reactant into an insulation kettle;
the reactants are stirred and heated to a pre-dehydration temperature.
7. The method for preparing clt acid by liquid phase baking according to claim 6, wherein: the pre-dehydration temperature is 120-135 ℃.
8. The method for preparing clt acid by liquid phase baking according to claim 6, wherein: the "pre-dewatering step" further comprises the steps of:
collecting gas phase separated by the heat preservation kettle, wherein the gas phase separated by the heat preservation kettle comprises the dispersion solvent and the water;
introducing the gas phase separated by the heat-preserving kettle into a water separator to obtain the dispersion solvent;
transferring the dispersion solvent into a heat preservation kettle.
9. A method for preparing clt acid by liquid phase baking according to claim 1, wherein: also includes a dehydration step;
the "dehydration step" further includes the steps of:
transferring the reactant into a baking kettle;
heating the reactants in the baking kettle to a dehydration temperature;
the dehydration temperature is maintained for a specified period of time to effect the indexing process.
10. A method for preparing clt acid by liquid phase baking according to claim 9, wherein: the dehydration temperature is 170-195 ℃.
11. A method for preparing clt acid by liquid phase baking according to claim 9, wherein: the "dehydration step" further includes the steps of:
collecting a gas phase separated by the baking kettle, wherein the gas phase separated by the baking kettle comprises the dispersion solvent and the water;
introducing the separated gas phase of the baking kettle into a water separator to obtain the dispersion solvent;
collecting the dispersion solvent.
12. A method for preparing clt acid by liquid phase baking according to claim 1, wherein: also includes a "detection step";
the "detecting step" includes the steps of:
detecting the clt acid;
when the acid is detected to be qualified, carrying out vacuum baking and drying treatment on the clt acid;
and cooling and collecting clt acid when the amino value is more than or equal to 98 percent.
13. A method for preparing clt acid by a liquid phase baking method according to any one of claims 1 to 12, characterized in that: the dispersion solvent adopts o-dichlorobenzene.
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