CN113527240A - Refining process of tetrachlorophthalic anhydride - Google Patents
Refining process of tetrachlorophthalic anhydride Download PDFInfo
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- CN113527240A CN113527240A CN202110814295.6A CN202110814295A CN113527240A CN 113527240 A CN113527240 A CN 113527240A CN 202110814295 A CN202110814295 A CN 202110814295A CN 113527240 A CN113527240 A CN 113527240A
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- C07D—HETEROCYCLIC COMPOUNDS
- C07D307/00—Heterocyclic compounds containing five-membered rings having one oxygen atom as the only ring hetero atom
- C07D307/77—Heterocyclic compounds containing five-membered rings having one oxygen atom as the only ring hetero atom ortho- or peri-condensed with carbocyclic rings or ring systems
- C07D307/87—Benzo [c] furans; Hydrogenated benzo [c] furans
- C07D307/89—Benzo [c] furans; Hydrogenated benzo [c] furans with two oxygen atoms directly attached in positions 1 and 3
Abstract
The application relates to the field of tetrachlorophthalic anhydride production, and particularly discloses a tetrachlorophthalic anhydride refining process, which comprises the following steps: s1: forming acid; s2: cooling and crystallizing for the first time; s3: drying; s4: anhydride formation; s5: cooling and crystallizing for the second time, and cooling, crystallizing and filtering the anhydride-forming mixed solution to obtain a tetrachlorophthalic anhydride refined primary product and an acetic acid recycling mother solution; s6: washing and drying, namely washing the primary tetrachlorophthalic anhydride refined product with clear water and then drying to obtain a tetrachlorophthalic anhydride refined product, and collecting the clear water after washing the primary tetrachlorophthalic anhydride refined product as washing water for later use; and mixing the acetic acid recycling mother liquor obtained in the step S5 with the washing water obtained in the step S6, and supplementing clear water to obtain an acetic acid recycling solution. The method has the effects of reducing the refining cost of tetrachlorophthalic anhydride and improving the refining efficiency.
Description
Technical Field
The invention relates to the field of tetrachlorophthalic anhydride purification, in particular to a tetrachlorophthalic anhydride refining process.
Background
Tetrachlorophthalic anhydride is a chemical mainly used for intermediates such as medicines, pesticides, dyes, pigments and the like, resin flame retardants and plastic reinforcing agents.
The industrial synthesis of tetrachlorophthalic anhydride is carried out by reacting phthalic anhydride with chlorine in chlorosulfonic acid solvent and iodine as catalyst. In industrial production, the production process of tetrachlorophthalic anhydride is accompanied by side reactions, and hexachlorobenzene and tetrachlorophthalic acid generated by the side reactions are main factors influencing the purity of the tetrachlorophthalic anhydride finished product. The purity of the tetrachlorophthalic anhydride finished product is generally required to be controlled to be more than 99.5 percent.
At present, crude tetrachlorophthalic anhydride obtained by industrial production is generally refined by the following steps: firstly heating and dissolving crude tetrachlorophthalic anhydride in an acetic acid solution to obtain tetrachlorophthalic acid, then separating by cooling crystallization to obtain tetrachlorophthalic acid solid, leaving most of hexachlorobenzene in the solution, and then heating and dissolving the tetrachlorophthalic acid solid by acetic anhydride to react, thereby re-reacting the tetrachlorophthalic acid solid back to the tetrachlorophthalic anhydride. The purity of the tetrachlorophthalic anhydride obtained after refining can reach more than 99.5 percent.
However, in the purification process of the related art, a large amount of acetic acid solution and water are consumed, which results in a large consumption of resources and a high cost.
Disclosure of Invention
In order to reduce the consumption of acetic acid in the refining process of tetrachlorophthalic anhydride, the application provides a refining process of tetrachlorophthalic anhydride.
A refining process of tetrachlorophthalic anhydride comprises the following steps:
s1: heating and dissolving the crude tetrachlorophthalic anhydride with an acetic acid reuse solution to obtain an acid formation mixed solution;
s2: cooling and crystallizing for the first time, and cooling, crystallizing and filtering the acid forming mixed solution to obtain acid forming crystals and acid forming waste liquid;
s3: drying, namely heating and drying after washing the acid crystal;
s4: forming anhydride, namely heating and thermally dissolving the acid forming crystal dried in the step S3 and an acetic anhydride solution to obtain an anhydride forming mixed solution;
s5: cooling and crystallizing for the second time, and cooling, crystallizing and filtering the anhydride-forming mixed solution to obtain a tetrachlorophthalic anhydride refined primary product and an acetic acid recycling mother solution;
s6: washing and drying, namely washing the primary tetrachlorophthalic anhydride refined product with clear water and then drying to obtain a tetrachlorophthalic anhydride refined product, and collecting the clear water after washing the primary tetrachlorophthalic anhydride refined product as washing water for later use;
and mixing the acetic acid recycling mother liquor obtained in the step S5 with the washing water obtained in the step S6, and supplementing clear water to obtain an acetic acid recycling solution.
By adopting the technical scheme, since acetic acid and tetrachlorophthalic acid are generated after the acetic anhydride reacts with tetrachlorophthalic acid, the main components of the acetic acid recycling mother liquor in the step S5 are acetic acid and water after the required tetrachlorophthalic anhydride product is filtered. Step S6 is mainly used for washing and removing the acetic acid remaining on the surface of the tetrachlorophthalic anhydride crystals, and therefore the main components of the washing water are also acetic acid and water. The acetic acid recycling mother liquor and the acetic acid contained in the washing water are prepared into the concentration which can be used for carrying out acid forming treatment on the tetrachlorophthalic anhydride crude product through supplementing clear water, so that the acetic acid recycling mother liquor and the acetic acid in the washing water are recycled, the raw material cost is reduced, and the resource utilization rate is improved.
Optionally, the cooling crystallization of the acid mixed solution in step S2 and the formation of acid from crude tetrachlorophthalic anhydride in step S1 are performed in the same apparatus, and the reaction of anhydride formation in step S4 and the second cooling crystallization in step S5 are performed in the same apparatus.
By adopting the technical scheme, the cooling crystallization is carried out in the same equipment for the previous step of reaction, so that the residual quantity of the mixed solution after the reaction in the equipment for the reaction and the conveying pipeline in the transferring process can be reduced, the product quantity obtained by the cooling crystallization is increased, and the yield is increased.
Optionally, the equipment that the cooling crystallization adopted in step S5 for the second time is an anhydride forming reaction kettle, the equipment that the drying washing adopted in step S6 is a washing centrifuge, the liquid outlet end of the anhydride forming reaction kettle is connected with a first pipeline, the liquid outlet end of the washing centrifuge is connected with a second pipeline, the equipment that adopts in the process of forming acid in step S1 is an acid forming reaction kettle, the liquid feed end of the acid forming reaction kettle is connected with a third pipeline, the first pipeline and the second pipeline are connected with the third pipeline through an acetic acid recycling solution mixing tank, the first pipeline and the second pipeline are connected with one end face of the acetic acid recycling solution mixing tank, the third pipeline is connected with the other end face of the acetic acid recycling solution mixing tank, the acetic acid recycling solution mixing tank is further connected with a supplementary pipeline for supplementing water, the first pipeline, the second pipeline, the third pipeline, And the third pipeline and the supplementary pipeline are both provided with water pumps.
Through adopting above-mentioned technical scheme, first pipeline is arranged in letting in the acetic acid retrieval and utilization mother liquor among step S5 in the acetic acid retrieval and utilization solution blending tank, and the second pipeline is arranged in letting in the washing liquid among step S6 in the acetic acid retrieval and utilization solution blending tank, and acetic acid retrieval and utilization solution blending tank is used for mixing acetic acid retrieval and utilization mother liquor and washing liquid to make the mixture of acetic acid retrieval and utilization mother liquor and washing liquid not need large-scale equipment such as reation kettle to stir alone and mix, reduced equipment cost, improved production efficiency.
Optionally, a filtering device is arranged at one end of the third pipeline, which is close to the end connected with the acetic acid recycling solution mixing tank, and the filtering device includes a filtering disc, a rotating assembly and a dirt suction assembly for sucking impurities on the filtering disc, the rotating assembly includes a rotating motor installed on the outer side wall of the third pipeline, a first magnetic wheel connected with an output shaft of the rotating motor in a key manner, and a second magnetic wheel rotatably installed in the third pipeline, a mounting hole for installing the filtering disc is formed in the center of the second magnetic wheel, the filtering disc is installed in the mounting hole, and the filtering disc is fixedly connected with the second magnetic wheel; the sewage suction assembly is arranged on the third pipeline.
Through adopting above-mentioned technical scheme, still have a small amount of dissolved tetrachlorophthalic anhydride in the acetic acid retrieval and utilization mother liquor, because the temperature reduces once more and takes place to separate out when acetic acid retrieval and utilization solution mixing tank mixed solution, filter equipment is used for filtering this part of tetrachlorophthalic anhydride solid that separates out to prevent that it from separating out and accumulating on the pipeline inner wall, avoid blockking up the pipeline. The rotatable drive filter disc of runner assembly rotates, and when the filter disc rotated, can be so that the soil pick-up subassembly carries out comprehensive decontamination to the filter disc, got rid of the impurity of accumulation on the filter disc to avoid long-term use in-process filter disc to take place to block up. The rotating assembly drives the first magnetic wheel to rotate through the rotating motor, the first magnetic wheel rotates to drive the second magnetic wheel to rotate, and the second magnetic wheel rotates to drive the filter disc to rotate. Through this drive mode, need not contact between first magnetic wheel and the second magnetic wheel, can improve the leakproofness of third pipeline with other drive filter disc pivoted mechanisms.
Optionally, the soil pick-up subassembly is including locating the sewage suction pipe that the filter disc is close to acetic acid retrieval and utilization solution blending tank one side, the hydraulic pressure chamber is installed outward to the third pipeline, sewage suction pipe one end links to each other with the inside wall of third pipeline, the lateral wall that the other end of sewage suction pipe passed the third pipeline is linked together with the hydraulic pressure chamber, be connected with the drain pipe on the hydraulic pressure chamber, install the solenoid valve on the drain pipe, the sewage suction pipe is connected with a plurality of suction nozzles that are used for absorbing impurity on the filter disc along the length direction of sewage suction pipe on being close to one side lateral wall of filter disc.
Through adopting above-mentioned technical scheme, when accumulating more impurity on the filter disc, form pressure differential around the filter disc. At this time, the solenoid valve is opened so that the drain pipe can drain the water in the water pressure chamber, and the pressure in the water pressure chamber is reduced due to the drainage of the water in the water pressure chamber, thereby forming a negative pressure at the suction nozzle. The suction nozzle inhales the impurity on the surface of the filter disc, and cleans up the filter disc along with the rotation of the filter disc, and the cleaning process is simple and rapid. And the pressure difference of both sides of the filter disc can be sensed by a sensor additionally provided with a control electromagnetic valve, so that automatic cleaning and decontamination are realized, and the efficiency is improved.
Optionally, acetic acid retrieval and utilization solution blending tank overcoat includes inlayer and skin, be equipped with the make-up water transition chamber between inlayer and the skin, first pipeline, second pipeline and third pipeline all pass inlayer and skin and solution blending tank inside in proper order and are linked together, the make-up water pipe is linked together with the make-up water transition chamber, all be equipped with a plurality of apopores that are linked together with the make-up water transition chamber on the inlayer, install the booster pump that is used for increasing make-up pipeline water pressure on the make-up pipeline, the water pressure of make-up water pipeline is greater than water pressure in the solution blending tank.
Through adopting above-mentioned technical scheme, the booster pump carries out the pressure boost to the third pipeline, and the clear water of replenishment usefulness flows into the make-up water transition intracavity from the third pipeline earlier, flows into the inside of inlayer through the apopore from the make-up water transition chamber again to make the replenishment of clear water more even.
Optionally, the water flow pressure of the water replenishing pipeline is 2 times of the water flow pressure in the solution mixing tank.
Through adopting above-mentioned technical scheme, the clear water can be followed apopore blowout one end distance for the clear water can play the effect of disturbance stirring to the mixed solution of inlayer inside when supplementing to the pressure of booster pump increase moisturizing pipeline for solution misce bene efficiency improves.
Optionally, the surfaces of the filter discs, the inner side walls of the first pipeline, the second pipeline and the third pipeline and the inner side wall of the inner layer of the acetic acid recycling solution mixing tank are coated with anti-sticking layers, and the anti-sticking layers are prepared from the following components in parts by weight:
100 portions and 150 portions of FEVE fluorocarbon resin;
1-3 parts of a defoaming agent;
2-4 parts of a dispersing agent;
nano Al2O34-6 parts of particles.
By adopting the technical scheme, the FEVE fluorocarbon resin has lower surface energy and is doped with nano Al2O3The particles can increase the roughness of the coating, thereby forming super-hydrophobic and self-cleaning capabilities similar to the lotus leaf surface, reducing the adhesive force of the acetic acid recycling solution, the acetic acid recycling mother liquor, the washing liquid and the like on the inner wall of the pipeline and the inner wall of the acetic acid recycling solution mixing tank, and reducing the adhesion of the tetrachlorophthalic anhydride separated out due to the temperature reduction in the acetic acid recycling solution mixing tank on the filter screen and the inner wall of the pipeline.
Optionally, the nano Al2O3The particles are pretreated and then used for preparing an anti-sticking layer, and the nano Al2O3The pretreatment of the microparticles comprises the following steps:
step 1: mixing nano Al2O3Dispersion of fine particlesIn ethanol solution to obtain primary dispersion liquid;
step 2: adding perfluorooctyl-triethoxysilane with the mass of 4% of the primary dispersion liquid into the primary dispersion liquid, and performing reflux reaction for 2 hours to obtain a primary reaction mixture;
and step 3: adding an epoxy silane coupling agent accounting for 2% of the mass of the primary dispersion liquid into the mixture for primary reaction, and stirring the mixture for reaction for 2 hours to obtain a reaction-finished mixture;
and 4, step 4: distilling the mixture after the reaction under reduced pressure to remove the solvent, and drying the solid after the distillation under reduced pressure in vacuum to obtain the pretreated nano Al2O3And (3) microparticles.
By adopting the technical scheme, the nano Al2O3After the particles are pretreated, nano Al2O3Increased activity of the particles, nano-Al2O3When the particles are used for preparing the anti-sticking layer, the nano Al2O3The dispersion of the particles is more uniform, and the formed coating film is more uniform and stable.
In summary, the present application includes at least one of the following beneficial technical effects:
1. the acetic acid recycling mother liquor and the washing liquid after the anhydride forming reaction in the tetrachlorophthalic anhydride refining process are recycled, so that the raw material cost in the acid forming reaction is greatly reduced;
2. the recovery efficiency of the acetic acid recycling mother liquor and the washing liquid is improved by utilizing structures such as an acetic acid recycling solution mixing tank;
3. the anti-sticking layer is coated on the surfaces of the acetic acid recycling solution mixing tank and each pipeline and the filter disc so as to reduce the adhesion of impurities in the solution on each inner wall and influence the recycling efficiency of the solution.
Drawings
FIG. 1 is a schematic structural diagram of an anhydride-forming reaction kettle, an acid-forming reaction kettle, an acetic acid recycling solution mixing tank and a centrifuge in example 1 of the present application;
FIG. 2 is a cross-sectional view of the acetic acid reuse solution mixing tank and a third pipe in example 1 of the present application;
fig. 3 is a perspective view of a filter device in example 1 of the present application.
Description of reference numerals: 1. an anhydride-forming reaction kettle; 2. an acid-forming reaction kettle; 3. washing the centrifuge; 4. a first conduit; 5. a second conduit; 6. a third pipeline; 7. an acetic acid recycling solution mixing tank; 71. an inner layer; 72. an outer layer; 73. a make-up water transition chamber; 74. a water outlet hole; 8. a water pipe is supplemented; 81. a booster pump; 9. a filtration device; 91. a filter tray; 912. a filtration pore; 92. a rotating assembly; 921. rotating the motor; 922. a first magnetic wheel; 923. a second magnetic wheel; 93. a dirt suction assembly; 931. a water pressure chamber; 932. a drain pipe; 933. a sewage suction pipe; 934. a suction nozzle; 935. an electromagnetic valve.
Detailed Description
The present application is described in further detail below with reference to figures 1-3.
Example 1:
the embodiment of the application discloses a tetrachlorophthalic anhydride refining process, which specifically comprises the following steps:
s1: adding 800kg of crude tetrachlorophthalic anhydride and 900kg of acetic acid recycling solution into an acid forming reaction kettle, controlling the temperature in the reaction kettle to be 110 ℃, and stirring at a stirring speed of 100r/min for 2 hours to obtain an acid forming mixed solution;
s2: cooling and crystallizing for the first time, reducing the temperature of the acid forming reaction kettle to 40 ℃, standing for 2 hours, then filtering the acid forming mixed solution by an impurity removal centrifugal machine, wherein the temperature of the impurity removal centrifugal machine is 25 ℃ at room temperature, and the rotating speed of the centrifugal machine is controlled to be 5000 r/min. And obtaining the finished acid crystal and the finished acid waste liquid, wherein the finished acid crystal is reserved, and the finished acid waste liquid is discarded.
S3: drying, washing the acid-forming crystal with clear water in an impurity removal centrifuge for 2 times, starting the impurity removal centrifuge again according to the conditions for filtering, and heating the filtered acid-forming crystal to 130 ℃ for drying;
s4: adding 800kg of finished acid crystals, 250kg of acetic anhydride and 3000kg of water which are dried in the step S3 into an anhydride forming reaction kettle, heating to 140 ℃, and stirring at a stirring speed of 100r/min for 2 hours to obtain an anhydride forming mixed solution;
s5: cooling and crystallizing for the second time, namely cooling the anhydride forming mixed solution to the room temperature of 25 ℃ in an anhydride forming cooling kettle, maintaining the room temperature for 2.5 hours for cooling and crystallizing, and filtering the cooled and crystallized anhydride forming mixed solution to obtain a tetrachlorophthalic anhydride refined primary product and an acetic acid recycling mother solution;
s6: washing and drying, putting the refined crude tetrachlorophthalic anhydride into a washing centrifuge for washing with clear water, wherein the temperature of the washing centrifuge is 25 ℃, the rotating speed is controlled at 5000r/min, and washing is carried out for 3 times. Then drying the washed and filtered primary tetrachlorophthalic anhydride refined product at 100 ℃ for 5 hours to obtain a tetrachlorophthalic anhydride refined product; the clean water for washing the tetrachlorophthalic anhydride refined primary product is used as washing water for later use.
In the above step, the acetic acid recycling mother liquor in the step S5, the washing water in the step S6 and the clean water are combined through an acetic acid recycling solution mixing tank to obtain an acetic acid recycling solution used in the acid forming process in the step S1.
Specifically, referring to fig. 1, a liquid outlet end of an anhydride forming reaction kettle 1 is fixedly connected with a first pipeline 4, a liquid outlet end of a washing centrifuge 3 is fixedly connected with a second pipeline 5, a liquid feeding end of an acid forming reaction kettle 2 is fixedly connected with a third pipeline 6, and the first pipeline 4, the second pipeline 5 and the third pipeline 6 are connected through an acetic acid recycling solution mixing tank 7. And the second pipeline 5 and the third pipeline 6 are respectively provided with a water pump for sending the solution in the second pipeline 5 and the third pipeline 6 into the acetic acid recycling solution mixing tank 7.
Referring to fig. 2, the acetic acid recycling solution mixing tank 7 is cylindrical, and the acetic acid recycling solution mixing tank 7 is horizontally disposed. The acetic acid recycling solution mixing tank 7 comprises an inner layer 71 and an outer layer 72 sleeved outside the inner layer 71, the first pipeline 4 and the second pipeline 5 are fixedly connected with the end face of one end of the outer layer 72, and the first pipeline 4 and the second pipeline 5 both penetrate through the outer layer 72 and the inner layer 71 and are communicated with the inner cavity of the inner layer 71; the third pipeline 6 is fixedly connected with the end face of the other end of the outer layer 72, and the third pipeline 6 also penetrates through the outer layer 72 and the inner layer 71 to be communicated with the inner cavity of the inner layer 71.
Referring to fig. 2, a supplementary water transition chamber 73 is formed between the outer layer 72 and the inner layer 71, and a supplementary water pipe 8 is fixedly connected to a circumferential side wall of the outer layer 72. One end of the supplementing water pipe 8 is fixedly connected with a water tank for supplying water, and the other end of the supplementing water pipe 8 penetrates through the outer layer 72 and is communicated with a supplementing water transition cavity 73. The water supply pipe 8 is also provided with a booster pump 81 for increasing the pressure of the water supply pipe 8. The inner layer 71 is evenly provided with water outlet holes 74 which are communicated with the supplementary water transition cavity 73 and the inner cavity of the inner layer 71.
Referring to fig. 2 and 3, the third pipe 6 is provided with a filtering device 9 near one end connected to the acetic acid reuse solution mixing tank 7. The filter device 9 includes a filter disc 91, a rotation assembly 92, and a dirt suction assembly 93 for sucking foreign substances on the filter disc 91. The rotating assembly 92 includes a rotating motor 921, a first magnetic wheel 922, and a second magnetic wheel 923. The rotating motor 921 is fixedly installed on the outer side wall of the third pipeline 6, the first magnetic wheel 922 is connected to the output shaft of the rotating motor 921 in a key mode, and the second magnetic wheel 923 is installed in the third pipeline 6 in a rotating mode. Specifically, a circle of mounting groove used for mounting the second magnetic wheel 923 is arranged on the peripheral side wall of the third pipeline 6 along the circumferential direction of the third pipeline 6, and the second magnetic wheel 923 is in running fit with the mounting groove.
Referring to fig. 3, a mounting hole with the diameter equal to the inner diameter of the third pipeline 6 is formed in the center of the second magnetic wheel 923, the filter disc 91 is mounted in the mounting hole, and the peripheral side wall of the filter disc 91 is fixedly connected with the inner wall of the second magnetic wheel 923. A plurality of filtering holes 912 are uniformly formed on the filtering plate 91.
Referring to fig. 3, the dirt suction assembly 93 includes a hydraulic pressure chamber 931, a drain pipe 932, a dirt suction pipe 933, and a suction nozzle 934 fixedly installed on an outer side wall of the third pipe 6, the drain pipe 932 is fixedly connected to one end of the hydraulic pressure chamber 931, and the dirt suction pipe 933 is fixedly connected to the other end of the hydraulic pressure chamber 931. One end of the drain pipe 932 is communicated with the inside of the water pressure chamber 931, and the other end of the drain pipe 932 is provided with an electromagnetic valve 935 for controlling the opening and closing of the drain pipe 932. The sewage suction pipe 933 is arranged inside the third pipeline 6, and the sewage suction pipe 933 is positioned on one side of the filter disc 91 close to the acetic acid recycling solution mixing tank 7. One end of the sewage suction pipe 933 penetrates through the side wall of the third pipeline 6 to be communicated with the interior of the hydraulic pressure chamber 931, and the other end of the sewage suction pipe 933 is fixedly connected with the inner wall of the third pipeline 6. The axis of the suction pipe 933 intersects with the axis of the third duct 6, and the axis of the suction pipe 933 is parallel to the surface of the filter tray 91.
Referring to fig. 3, a suction nozzle 934 is fixedly attached to a side wall of the suction pipe 933 on a side close to the filter tray 91. The number of the suction nozzles 934 is 5 in total, and the 5 suction nozzles 934 are equidistantly arranged in the longitudinal direction of the dirt suction pipe 933. The end, far away from the suction nozzle 934, connected with the dirt suction pipe 933 is just opposite to the surface of the filter disc 91, and the distance between the end face of the suction nozzle 934 and the surface of the filter disc 91 is 2 mm.
The implementation principle of the acetic acid recycling solution mixing tank 7 in the embodiment 1 of the application is as follows: the solution in the anhydride-forming reaction kettle 1 and the solution in the washing centrifuge 3 respectively enter an acetic acid recycling solution mixing tank 7 through a first pipeline 4 and a second pipeline 5, and meanwhile, a water supplementing pipe 8 supplements clear water to the acetic acid recycling solution mixing tank 7. The pressure of the supplementing water pipe 8 is increased by the booster pump 81 on the supplementing water pipe 8, so that the water flow pressure in the supplementing water pipe 8 is greater than the water flow pressure in the acetic acid recycling solution mixing tank 7, so that the pressure of the clear water flowing into the supplementing water transition cavity from the supplementing water pipe 8 when flowing out from the water outlet 74 is greater than the water pressure of the acetic acid recycling solution mixing tank 7, so that the clear water can smoothly flow into the acetic acid recycling solution mixing tank 7, and the clear water flowing into the acetic acid recycling solution mixing tank 7 from the water outlet 74 can disturb the water flow in the acetic acid recycling solution mixing tank 7 by adjusting the pressure of the booster pump 81.
The mixed solution mixed by the acetic acid recycling solution mixing tank 7 flows into the third pipeline 6, and is introduced into the acid forming reaction kettle 2 after impurities are filtered by the filtering device 9.
Example 2
The difference from example 1 is that: the surfaces of the filter discs, the inner side walls of the first pipeline, the second pipeline and the third pipeline and the inner side wall of the inner layer of the acetic acid recycling solution mixing tank are respectively coated with an anti-sticking layer, and the anti-sticking layers comprise the following components in parts by weight:
150kg of FEVE fluorocarbon resin;
3kg of defoaming agent;
4kg of dispersing agent;
nano Al2O36kg of fine particles.
Wherein, the FEVE fluorocarbon resin adopts the FEVE fluorocarbon resin of CMY87 produced by Shenzhenming far fluorine coating company Limited, and the antifoaming agent adopts the DF101 antifoaming agent produced by Shenlan trade company Limited in Guangzhou city; the dispersant adopts Shanghai Mingda chemical industrySN-5040 dispersant manufactured by Limited corporation. Nano Al2O3Nanometer Al with particle diameter of 30-60nm and trade mark HG produced by Shanghai Huizi Jing sub-nanometer new material Limited2O3And (3) microparticles.
The preparation steps of the anti-sticking layer are as follows: FEVE fluorocarbon resin, defoaming agent, dispersing agent and nano Al in the weight ratio2O3And adding the particles into a high-speed mixer, mixing for 10min at the rotating speed of 5000r/min, heating the mixed mixture by using a double-screw extruder, and carrying out melt extrusion to obtain the powder coating. And then spraying the powder coating on the surface of the filter disc, the inner side walls of the first pipeline, the second pipeline and the third pipeline and the inner side wall of the inner layer of the acetic acid recycling solution mixing tank by using an electrostatic spraying device.
Examples 3 to 10
The difference from example 2 is that: the weight of each raw material in the anti-sticking layer is shown in the following table 1.
TABLE 1 proportion of raw materials in the anti-sticking layer
Example 11
The difference from example 9 is that nano Al2O3The microparticles were pretreated as follows:
step 1: mixing 6kg of nano Al2O3Adding the particles into 2L ethanol solution, and stirring at a stirring speed of 100r/min for 20min to obtain primary dispersion;
step 2: adding perfluorooctyl-triethoxysilane with the mass of 4% of the primary dispersion liquid into the primary dispersion liquid, and stirring and refluxing for 2h at the stirring speed of 50r/min to obtain a primary reaction mixture;
and step 3: adding an epoxy silane coupling agent accounting for 2% of the mass of the primary dispersion liquid into the primary reaction mixture, and stirring for 2 hours at a stirring speed of 50r/min to obtain a reaction-finished mixture;
and 4, step 4: distilling the mixture after the reaction under reduced pressure to remove the solvent, and drying the solid after the distillation under reduced pressure at 50 ℃ in vacuum to obtain the pretreated nano Al2O3And (3) microparticles.
Comparative example
Comparative example 1
The difference from the embodiment 1 is that the acetic acid recycling solution adopts 20% by mass of acetic acid solution.
Comparative example 2
The difference from example 1 is that nano Al is not added to the raw material of the anti-sticking layer2O3And (3) microparticles.
Detection method
1. By comparison of actual production, example 1 and comparative example 1, when the same amount of tetrachlorophthalic anhydride is produced by purification, the cost of example 1 is about 30% lower than that of comparative example 1.
2. Anti-adhesive capability test of anti-adhesive layer
The anti-sticking layers of examples 2 to 6 and the anti-sticking layer of comparative example 2 were sprayed on a stainless steel plate of 10cm × 10cm, respectively, and then olive oil having a thickness of about 2mm was uniformly sprayed on the surface of the stainless steel plate, and then the stainless steel plate was vertically hung, and the area of the remaining oil stain on the surface of the stainless steel plate was observed after 1h, 5h, and 10h, and classified into 1-10 grades in order according to the area size.
TABLE 2 sample oil stain residue grade on stainless steel plate surface
And (4) conclusion: it can be clearly seen from the comparison of example 1 with comparative example 1 that the cost of acid formation is greatly reduced by using acetic acid in the acetic acid recycling mother liquor and the washing liquor in the application. Next, the results are combined with comparative example 2 by examples 2 to 11As can be seen from Table 2, the anti-sticking layer significantly reduces the adhesion of the inner walls of the pipeline and the like to the solution, and the nano Al2O3The addition of the particles can further increase the separating capacity, and the pretreated nano Al2O3The oleophobic power of the particles is further enhanced. And the mechanism of the oil repellency of the anti-sticking layer is similar to that of lotus leaves in the application, so that the oil agent has better separating capacity, and the aqueous solution has better separating capacity.
The present embodiment is only for explaining the present application, and it is not limited to the present application, and those skilled in the art can make modifications of the present embodiment without inventive contribution as needed after reading the present specification, but all of them are protected by patent law within the scope of the claims of the present application.
Claims (9)
1. A refining process of tetrachlorophthalic anhydride is characterized by comprising the following steps: the method comprises the following steps:
s1: heating and dissolving the crude tetrachlorophthalic anhydride with an acetic acid reuse solution to obtain an acid formation mixed solution;
s2: cooling and crystallizing for the first time, and cooling, crystallizing and filtering the acid forming mixed solution to obtain acid forming crystals and acid forming waste liquid;
s3: drying, namely heating and drying after washing the acid crystal;
s4: forming anhydride, namely heating and thermally dissolving the acid forming crystal dried in the step S3 and an acetic anhydride solution to obtain an anhydride forming mixed solution;
s5: cooling and crystallizing for the second time, and cooling, crystallizing and filtering the anhydride-forming mixed solution to obtain a tetrachlorophthalic anhydride refined primary product and an acetic acid recycling mother solution;
s6: washing and drying, namely washing the primary tetrachlorophthalic anhydride refined product with clear water and then drying to obtain a tetrachlorophthalic anhydride refined product, and collecting the clear water after washing the primary tetrachlorophthalic anhydride refined product as washing water for later use;
and mixing the acetic acid recycling mother liquor obtained in the step S5 with the washing water obtained in the step S6, and supplementing clear water to obtain an acetic acid recycling solution.
2. The refining process of tetrachlorophthalic anhydride according to claim 1, characterized in that: the cooling crystallization of the acid mixed liquid in the step S2 and the acid formation of the crude tetrachlorophthalic anhydride in the step S1 are carried out in the same equipment, and the reaction of anhydride formation in the step S4 and the second cooling crystallization of the step S5 are carried out in the same equipment.
3. The refining process of tetrachlorophthalic anhydride according to claim 2, characterized in that: the equipment adopted by the second cooling crystallization in the step S5 is an anhydride forming reaction kettle (1), the equipment adopted by the drying and washing in the step S6 is a washing centrifuge (3), the liquid outlet end of the anhydride forming reaction kettle (1) is connected with a first pipeline (4), the liquid outlet end of the washing centrifuge (3) is connected with a second pipeline (5), the equipment adopted in the acid forming process in the step S1 is an acid forming reaction kettle (2), the liquid feed end of the acid forming reaction kettle (2) is connected with a third pipeline (6), the first pipeline (4) and the second pipeline (5) are connected with the third pipeline (6) through an acetic acid recycling solution mixing tank (7), the first pipeline (4) and the second pipeline (5) are connected with one end face of the acetic acid recycling solution mixing tank (7), the third pipeline (6) is connected with the other end face of the acetic acid recycling solution mixing tank (7), and a supplementing pipeline for supplementing water is also connected to the acetic acid recycling solution mixing tank (7).
4. The refining process of tetrachlorophthalic anhydride according to claim 3, wherein: the third pipeline (6) is close to the one end that links to each other with acetic acid retrieval and utilization solution blending tank (7) and is equipped with filter equipment (9), filter equipment (9) include filter disc (91), runner assembly (92) and be used for absorbing dirt absorbing assembly (93) of impurity on filter disc (91), runner assembly (92) are including installing rotation motor (921) on third pipeline (6) lateral wall, with first magnetic force wheel (922) of the output shaft key-type connection of rotation motor (921) and rotate the second magnetic force wheel (923) of installing in third pipeline (6), the mounting hole that is used for installing filter disc (91) is seted up at second magnetic force wheel (923) center, filter disc (91) are installed in the mounting hole, just filter disc (91) are connected with second magnetic force wheel (923) is fixed; the sewage suction assembly (93) is arranged on the third pipeline (6).
5. The refining process of tetrachlorophthalic anhydride according to claim 4, wherein: soil pick-up subassembly (93) are including locating sewage pick-up pipe (933) that filter disc (91) are close to acetic acid retrieval and utilization solution blending tank (7) one side, water pressure chamber (931) are installed outward in third pipeline (6), sewage pick-up pipe (933) one end links to each other with the inside wall of third pipeline (6), the lateral wall that the other end of sewage pick-up pipe (933) passed third pipeline (6) is linked together with water pressure chamber (931), be connected with drain pipe (932) on water pressure chamber (931), install solenoid valve (935) on drain pipe (932), sewage pick-up pipe (933) are connected with a plurality of suction nozzles (934) that are used for absorbing impurity on filter disc (91) along the length direction of sewage pick-up pipe (933) on being close to one side lateral wall of filter disc (91).
6. The refining process of tetrachlorophthalic anhydride according to claim 3, wherein: acetic acid retrieval and utilization solution blending tank (7) overcoat includes inlayer (71) and skin (72), be equipped with make-up water transition chamber (73) between inlayer (71) and skin (72), first pipeline (4), second pipeline (5) and third pipeline (6) all pass inlayer (71) and skin (72) and acetic acid retrieval and utilization solution blending tank (7) inside in proper order and are linked together, make-up water pipe (8) are linked together with make-up water transition chamber (73), all be equipped with apopore (74) that a plurality of and make-up water transition chamber (73) are linked together on inlayer (71), install booster pump (81) that are used for increasing make-up pipeline hydraulic on the make-up pipeline, the water pressure of make-up water pipeline is greater than water pressure in the solution blending tank.
7. The refining process of tetrachlorophthalic anhydride according to claim 3, wherein: the water flow pressure of the water replenishing pipeline is 2 times of the water flow pressure in the solution mixing tank.
8. The refining process of tetrachlorophthalic anhydride according to claim 3, wherein: the surface of the filter disc (91), the inner side walls of the first pipeline (4), the second pipeline (5) and the third pipeline (6) and the inner side wall of the inner layer (71) of the acetic acid recycling solution mixing tank (7) are coated with anti-sticking layers, and the anti-sticking layers comprise the following components in parts by weight:
100 portions and 150 portions of FEVE fluorocarbon resin;
1-3 parts of a defoaming agent;
2-4 parts of a dispersing agent;
nano Al2O34-6 parts of particles.
9. The refining process of tetrachlorophthalic anhydride according to claim 8, wherein: the nano Al2O3The particles are pretreated and then used for preparing an anti-sticking layer, and the nano Al2O3The pretreatment of the microparticles comprises the following steps:
step 1: mixing nano Al2O3Dispersing the particles in an ethanol solution to obtain a primary dispersion liquid;
step 2: adding perfluorooctyl-triethoxysilane with the mass of 4% of the primary dispersion liquid into the primary dispersion liquid, and performing reflux reaction for 2 hours to obtain a primary reaction mixture;
and step 3: adding an epoxy silane coupling agent accounting for 2% of the mass of the primary dispersion liquid into the mixture for primary reaction, and stirring the mixture for reaction for 2 hours to obtain a reaction-finished mixture;
and 4, step 4: distilling the mixture after the reaction under reduced pressure to remove the solvent, and drying the solid after the distillation under reduced pressure in vacuum to obtain the pretreated nano Al2O3And (3) microparticles.
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