CN114479082B - Clean production process of polyphenylene sulfide and treatment method of polyphenylene sulfide reaction liquid - Google Patents
Clean production process of polyphenylene sulfide and treatment method of polyphenylene sulfide reaction liquid Download PDFInfo
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Abstract
The application discloses a clean production process of polyphenylene sulfide and a treatment method of a polyphenylene sulfide reaction liquid, wherein the treatment method of the polyphenylene sulfide reaction liquid comprises the following steps: (1) The polyphenylene sulfide reaction liquid is subjected to flash evaporation to obtain solid, then the solid is washed by deionized water, the obtained washing wastewater is filtered to remove PPS fine particles, then the obtained washing wastewater is acidified, and a filter filled with PPS fiber balls is used for filtering to obtain filtered acidic wastewater; (2) And (3) blowing the acidic wastewater obtained in the step (1) to remove hydrogen sulfide, then adsorbing by adopting methyl methacrylate-acrylic acid-styrene-divinylbenzene copolymerized macroporous resin, concentrating and distilling the adsorbed wastewater to obtain sodium chloride and recovered condensed water. The clean production process of the polyphenylene sulfide can obviously reduce organic matters in the wastewater, reduce TOC content, facilitate the application of the wastewater, and obtain sodium chloride byproducts with better quality.
Description
Technical Field
The application belongs to the field of high polymer materials, and particularly relates to a clean production process of polyphenylene sulfide and a treatment method of a polyphenylene sulfide reaction solution.
Background
Polyphenylene sulfide, also called polyphenylene sulfide (Polyphenylene Sulfide, abbreviated as PPS), has a macromolecular rigid structure formed by alternately connecting benzene rings with sulfur atoms, and imparts highly stable chemical properties to the molecule, so that the polyphenylene sulfide resin has the characteristics of high temperature resistance, radiation resistance, flame retardance, low viscosity, high dimensional stability, good solvent and chemical resistance, good dielectric properties, wear resistance and the like. The polyphenylene sulfide has good performance, and has good affinity with inorganic filler and reinforcing fiber and compatibility with other high polymer materials, so that the polyphenylene sulfide can be prepared into various reinforcing fillers and high polymer alloys, has very wide application, and is mainly used in the industries of electronic appliances, precise instruments, machinery, automobiles, household appliances, film fields, fiber fields, electric power, aviation, environmental protection, chemistry and the like.
There are various methods for synthesizing PPS reported in the literature, but most of the commercial units currently employ a method for synthesizing PPS by solution polycondensation using a sulfide and a dihaloaromatic compound, and then further processing to obtain the final product, wherein the sulfide is mainly sodium sulfide or sodium hydrosulfide, and the solvent is mainly N-methylpyrrolidone (NMP). The reaction byproducts are mainly sodium chloride, and are separated out in the reaction process, and 1.08 tons of byproduct sodium chloride can be produced per 1 ton of PPS produced on average. To promote the stable and rapid progress of the reaction, a large amount of organic or inorganic salt auxiliary agents such as sodium acetate and C are added into the reaction system 5 -C 6 Carboxylate, sodium benzoate and lithium chloride. A certain amount of small molecule organic byproducts are also generated during the reaction. These by-products and auxiliary agents as well as the unreacted and complete raw materials sodium sulfide, paradichlorobenzene, NMP, etc. are separated out with the product in a small part or even a great part after the reaction is finished, and a large amount of water is needed to be used for washing and removing for many times in the subsequent product purification, so that a large amount of high-salinity high-TOC sulfur-containing wastewater is generated, and pretreatment is needed to reduce the content of pollutants in the discharged wastewater.
According to the difference of the solvent separation modes of the products after the polymerization reaction is finished, the production process of PPS can be divided into two main types, namely a cooling crystallization process, namely the precipitation of the products through slow cooling, the separation of the products into a byproduct salt-containing product filter cake and byproduct slurry after filtration, and further washing and purifying the product filter cake, wherein part of low molecular weight PPS and small molecular reaction byproducts in the process can be taken away by the solvent, and accordingly the content of the byproducts in the washing wastewater is reduced; the other process is called flash evaporation, namely the reaction mixed solution is directly cooled to normal pressure for flash evaporation without temperature reduction, most of small molecular reaction byproducts are remained in the product except a small amount of low-boiling components, and finally enter washing wastewater, so that the content of organic byproducts in the wastewater is higher.
In order to reduce the content of pollutants in the wastewater discharged in the PPS production process, a large amount of byproduct sodium chloride and possibly contained auxiliary salt in the wastewater are required to be recovered, and meanwhile, the content of organic matters in the wastewater is reduced. Patent CN102730721B reports a method for recovering sodium chloride from washing wastewater in polyphenylene sulfide production, which uses activated carbon to adsorb and remove organic matters in sodium chloride aqueous solution, the adsorbed sodium chloride aqueous solution is injected into a multi-effect distillation system to be concentrated, after sodium chloride is separated out, solid-liquid separation is carried out to obtain sodium chloride crystals, the sodium chloride content is above 95%, and the water insoluble content is less than 0.2%. The patent CN108586746A mixes NMP distillation residues with washing wastewater, filters out low-quality PPS precipitated therein, extracts the filtrate by using an extracting agent, and the extracted aqueous solution is concentrated by section evaporation to recover sodium chloride and auxiliary lithium chloride, so that the content of dry salt sodium chloride is 98.7%, and the purity of the dry salt lithium chloride is 98.4%. The patent CN106395862B mixes the byproduct slurry and the washing wastewater, removes residual sodium sulfide and low-quality PPS by combining acidification, aeration and multiple times of filtration, then rectifies and removes water, and sodium chloride separated out from a tower kettle in the water removal process is filtered, washed by saturated saline water and dried to obtain byproduct sodium chloride, wherein the purity of the recovered byproduct sodium chloride is more than or equal to 99.55wt%, and the content of the low-molecular polymer is less than or equal to 0.3wt%. In the production process reported in the foregoing patent, a method of evaporating salt and concentrating wastewater is mostly adopted for recycling byproduct sodium chloride, but organic matters in the wastewater before evaporating salt are not sufficiently removed, and are precipitated into the byproduct salt in the process of evaporating salt, so that the total organic matter content (TOC) in the byproduct salt is high (wherein CN106395862B only gives low molecular polymer content, but contains other organic matter impurities besides the low molecular polymer, so that the content of the low molecular polymer cannot completely represent the content of actual organic matter impurities yet, and with the improvement of waste standards, the standard of industrial sodium chloride may not be met, and the byproduct sodium chloride becomes dangerous waste chemical. Patent CN111253573a reports that, after the byproduct slurry and the washing wastewater are mixed, the precipitated low-quality PPS is removed by filtration, the water and NMP are removed by rectifying the filtered mixed filtrate, the organic matters in the distilled residues containing the byproduct sodium chloride and the auxiliary lithium chloride are sufficiently removed by incineration, the organic matters are recovered by fractional concentration after redissolution, but all the byproduct salt and the auxiliary lithium chloride are required to be incinerated, the treatment capacity is large, and the energy consumption cost and the carbon emission of the incineration mode are too high.
Disclosure of Invention
The technical problems to be solved by the application are as follows: the clean production process can reduce the total organic matter content (TOC) in the generated washing wastewater, thereby obviously reducing byproduct sodium chloride and recovering TOC in condensed water, facilitating the further treatment of byproduct salt and the application of wastewater, and being more environment-friendly.
The inventor of the present application conducted intensive studies on the components of organic matters in polyphenylene sulfide washing wastewater, and found that the organic matters in the washing wastewater are mainly classified into the following three types:
(1) Organic matter of a first type: water-insoluble PPS fines, mainly derived from leakage from the water-wash filtration step;
(2) Organic matter of the second kind: the water-soluble oligomer (mainly dimer and trimer) containing polar end groups (amino, mercapto (sodium) and carboxylic acid (sodium)) is mostly converted into a non-organic salt form with poor water solubility to be separated out from the wastewater when the pH of the wastewater is regulated to be acidic, and is formed into micron-sized oily liquid drops with certain viscosity;
(3) Third class of organics: NMP and byproducts thereof such as 2-pyrrolidone, N-methyl butanediamide; paradichlorobenzene and by-products derived therefrom, such as phenol (sodium), 4-chloro-N-methylaniline, p-chlorophenylthiol (sodium), 4- [ (4-chlorophenyl) -methylamino ] -butyric acid (sodium, abbreviated as CP-SMAB), and 4- { [4- (4-chlorophenylthio) -phenyl ] -methylamino } -butyric acid (sodium). Wherein the structures of 4- [ (4-chlorophenyl) -methylamino ] -butyric acid and 4- { [4- (4-chlorophenyl-thio) -phenyl ] -methylamino } -butyric acid are as follows:
according to the problems reported in the prior literature and combining the research results, the application provides the following technical scheme:
a method for treating polyphenylene sulfide reaction liquid comprises the following steps:
(1) The polyphenylene sulfide reaction liquid is subjected to flash evaporation to obtain a solid, then the solid is washed by deionized water, the washed solid is dried to obtain a polyphenylene sulfide product, washing wastewater obtained after washing is filtered to remove PPS fine particles, then acidification is carried out, and a filter filled with PPS fiber balls is used for filtering to obtain filtered acidic wastewater;
(2) Stripping and blowing the acid wastewater obtained in the step (1) to remove hydrogen sulfide, and then adsorbing by adopting methyl methacrylate-acrylic acid-styrene-divinylbenzene copolymerized macroporous resin, concentrating and distilling the adsorbed wastewater to obtain sodium chloride and recovered condensed water;
the polyphenylene sulfide reaction liquid is obtained by carrying out solution polycondensation reaction on a sulfur-containing compound and paradichlorobenzene.
The core of the process is as follows: (1) The organic matters separated out after the acid adjustment of the wastewater are mainly second-class organic matter impurities, are PPS oligomers with small molecular weight, are dispersed in the wastewater in the form of micron-sized liquid drops and are difficult to remove by adopting a common filtering mode, the PPS fiber balls with the structure similar to that of the precipitates are used, the precipitates are contacted with PPS fibers in the PPS fiber balls, and are rapidly adhered to the surfaces of the fibers so as to be intercepted and removed, and the turbidity of the wastewater can be reduced to about 10NTU from more than 300NTU at the minimum before and after the filtering step; (2) The organic remaining after filtration using PPS fiber balls is predominantly the third class of organic with better water solubility, typically representing, for example, 2-pyrrolidone, 4-chloro-N-methylaniline, p-chlorophenylthiol (sodium), N-methylsuccinamide and 4- [ (4-chlorophenyl) -methylamino ] -butyric acid (sodium), 4- { [4- (4-chlorophenylthio) -phenyl ] -methylamino } -butyric acid (sodium). The application uses specially customized methyl methacrylate, acrylic acid, styrene and divinylbenzene multi-component copolymerization crosslinking macroporous resin, can effectively remove the organic matters, can reduce the TOC of wastewater to below 200ppm at the minimum after resin adsorption, and has cleaner final whole process, higher purity of byproduct sodium chloride, fewer impurities and higher utilization value.
Preferably, in the step (1), the fine PPS particles are removed by filtration using a fine filter having a filtration mesh number of 1000 to 7500 mesh, more preferably 2000 to 4000 mesh, and most preferably 3000 mesh.
In the step (1), the acid used for acidification is not particularly strict, and common inorganic acid is selected: for example hydrochloric acid, phosphoric acid or sulfuric acid, preferably in step (1), the pH of the waste water after acidification is between 2 and 5, more preferably between 2 and 4, and the acid used is further preferably hydrochloric acid, which pH range may be advantageous for the precipitation of the second type of organic substances from the waste water, more advantageously for subsequent filtration.
In the present application, the PPS fiber balls may affect the removal efficiency of the second type of organic matter, and preferably, in the step (1), the PPS fiber balls are spheres woven from PPS fibers, and the porosity is 50 to 95%, and more preferably 65 to 90%; more preferably, the fineness of PPS fibers used for preparing PPS fiber balls is 0.5 to 4 denier (D); further preferably, the fineness of the PPS fiber is 1 to 2.5D.
Preferably, in the step (2), the pH of the waste water after stripping is adjusted to be between 5 and 9, and then the subsequent resin adsorption is performed. The stripped hydrogen sulfide is absorbed by sodium hydroxide solution to prepare sodium hydrosulfide solution which is reused as reaction raw material.
In the step (2), the obtained condensed water is reused as water for multiple washing.
In the present application, a specific methyl methacrylate-acrylic acid-styrene-divinylbenzene copolymerized macroporous resin is used to remove the third organic matters, preferably, in the step (2), theThe methyl methacrylate-acrylic acid-styrene-divinylbenzene copolymerized macroporous resin is prepared by suspension polymerization, wherein the molar ratio of methyl methacrylate monomer, acrylic acid monomer, styrene monomer and divinylbenzene monomer in raw materials is 5-30: 1 to 5: 60-90: 1 to 10, more preferably 5 to 15:3 to 5: 77-85: 4 to 8; as a further preferred aspect, the methyl methacrylate-acrylic acid-styrene-divinylbenzene copolymerized macroporous resin has an average pore diameter of 10 to 15nm and a specific surface area of 90 to 150m 2 /g; as a further preferred aspect, the methyl methacrylate-acrylic acid-styrene-divinylbenzene copolymerized macroporous resin has an average pore diameter of 10 to 12nm and a specific surface area of 90 to 100m 2 /g。
Further, the preparation method of the methyl methacrylate-acrylic acid-styrene-divinylbenzene copolymerized macroporous resin comprises the following steps:
under the action of a free radical initiator, carrying out suspension polymerization reaction on a water phase containing an emulsifier and water and an oil phase containing a pore-forming agent and the monomers, and after the reaction is finished, carrying out post-treatment to obtain the methyl methacrylate-acrylic acid-styrene-divinylbenzene copolymerized macroporous resin.
Further, the free radical initiator is azobisisobutyronitrile.
Further, the pore-forming agent is selected from one or more of n-heptane, toluene and xylene.
Further, the molar ratio of the pore-forming agent to the total monomer is 0.5-2:1.
Further, the mass ratio of the water phase to the oil phase is 2-4:1.
Further, the emulsifier is selected from one or more of polyvinyl alcohol (PVA), polyoxyethylene polyoxypropylene block copolymer, fatty alcohol polyoxyethylene ether (AEO) and sorbitan fatty acid ester (Span).
Further, the polymerization temperature is 60-80 ℃, and the polymerization time is 3-8 h.
The application also discloses a clean production process of the polyphenylene sulfide, which comprises the following steps:
and carrying out solution polycondensation reaction on the sulfur-containing compound and paradichlorobenzene to obtain a polyphenylene sulfide reaction solution, and treating the polyphenylene sulfide reaction solution according to the treatment method to obtain a polyphenylene sulfide product and sodium chloride as a byproduct.
In the present application, the solution polycondensation reaction is the prior art, and the specific process can be referred to in numerous prior patent applications, for example: patent documents CN 106395862A, CN111253573A, CN 106633062A, CN 103897187A, and the like. The obtained polyphenylene sulfide reaction solution is filtered and washed, and the obtained washing solution contains the second-class organic matters and the third-class organic matters.
Wherein the sulfur-containing compound can be sodium sulfide or sodium hydrosulfide;
the solvent used in the solution polycondensation reaction is preferably NMP;
the solution polycondensation is carried out under alkaline conditions, for example under the action of sodium hydroxide.
One or more auxiliary agents such as sodium acetate and C can be added into the solution polycondensation reaction 5 -C 6 Carboxylate, sodium benzoate, lithium chloride, and the like.
Further, the clean production process of the polyphenylene sulfide comprises the following specific steps:
(A) Adding NMP and 40-50% NaOH aqueous solution into a reaction kettle, heating to 120-140 ℃, preserving heat for 1-3 hours, heating to 180-200 ℃ for dehydration, and cooling to 120-140 ℃ after dehydration;
(B) Adding NaHS aqueous solution and NMP into a reaction kettle after the step (A) is finished, stirring and under the protection of nitrogen, heating to 180-220 ℃ for dehydration, cooling to 140-160 ℃ after the dehydration, and absorbing hydrogen sulfide volatilized in the dehydration process by adopting sodium hydroxide solution to prepare sodium hydrosulfide solution for reuse as a reaction raw material;
(C) Adding p-dichlorobenzene (hereinafter referred to as PDCB) and NMP into a reaction kettle after the step (B) is finished, performing polycondensation reaction at 210-280 ℃, performing solid-liquid separation through flash evaporation after the reaction is finished to obtain a crude solvent, washing the separated solid twice by deionized water at 70-100 ℃, mixing filtrate generated by the two times of washing to obtain washing wastewater, and drying a filter cake to obtain a linear PPS product; the linear PPS product can be heated under the oxidizing gas atmosphere to carry out thermo-oxidative crosslinking, so as to obtain crosslinked PPS products with different Melt Fluidity (MFR);
(D) The crude solvent obtained by separation in the step (C) is firstly subjected to crude distillation to azeotropically distill out water and paradichlorobenzene, the paradichlorobenzene is separated and recycled, then NMP is distilled out and recycled through rectification, and a small amount of residual tower substrates are burnt to generate heat source steam;
(E) In the step (C), washing wastewater is generated, and sodium chloride crystals and condensed water are obtained by precise filtration (filtrate I), hydrochloric acid acidification (turbid liquid I), PPS fiber ball filtration (filtrate II), stripping, macroporous resin adsorption (filtrate III) and distillation concentration in sequence according to the method.
The raw materials used in the step (A) are 1.5 to 2.5mol of NMP and 1.0 to 1.1mol of NaOH based on 1.0mol of NaHS.
The raw materials used in the step (B) are based on 1.0mol of NaHS, and after NaHS and NMP are added, the total NMP of the system is 2.0-3.0 mol.
The raw materials used in the step (C) are based on 1.0mol of NaHS, after PDCB and NMP are added, the PDCB is 0.99-1.10 mol, and the total NMP of the system is 3-4 mol; in the multiple water washing steps, the washing water consumption is 4-6 parts, preferably 5 parts, based on 1 part of PPS mass; in the thermal oxygen crosslinking step, the oxygen content in the crosslinking atmosphere is 8-21%, preferably 8-12%, and the crosslinking temperature is 220-280 ℃, preferably 230-250 ℃.
Compared with the prior art, the application has the beneficial effects that:
(1) The organic matters in the waste water are fully removed by multistage precision filtration, PPS fiber ball filtration, blowing, specific adsorption and the like, then a multi-effect distillation system is used for concentrating and recycling byproduct sodium chloride, the total content (TOC) of the organic matters in the recycled sodium chloride is as low as 800ppm, the quality requirement of industrial sodium chloride is fully met, the TOC content in condensed water produced by distillation and concentration is lower than 200ppm, and the condensed water can be recycled as washing water, so that the production water consumption is greatly reduced.
(2) After the organic matters in the waste liquid are sufficiently removed, the surface tension of the waste water is reduced, the foaming phenomenon in the concentration and salt steaming process is obviously improved, and the production stability is improved.
Detailed Description
The process of the present application is further described in detail below with reference to examples. The test methods involved in the examples are as follows:
melt Flow Rate (MFR) test: the melt flowability of the PPS resin was measured by using GOTTFERT MI-2.2, germany, with reference to national standard GB/T3682-2000, at 315.6 ℃. Weighing 8g of dried sample, quickly adding the sample into a charging barrel, compacting by a sample injection rod, adding a piston rod and a 5kg load weight, preheating for 5min, removing a lower thimble to allow the sample to naturally flow downwards, cutting off by scissors when the scale mark under the piston rod just disappears in the sight line, catching the effluent by a bowl, starting timing by a stopwatch, cutting off again by scissors when the scale mark on the piston rod disappears in the sight line, stopping timing, and removing the bowl. The mass M of the sample was weighed using a balance, and the recording time t(s) of the stopwatch was read, MFR (g/10 min) =m×600/t.
Liquid phase analysis of wastewater composition: organics in the wastewater such as NMP, CP-SMAB, 4-chloro-N-methylaniline, SMAB, etc. can be quantitatively analyzed by High Performance Liquid Chromatography (HPLC) equipped with a light emitting diode array detector. The chromatographic column used was a C18 column at a temperature of 30deg.C and a mobile phase of 0.15% phosphoric acid in water (30%) +methanol (70%), at a flow rate of 0.5mL/min.
Total Organic Carbon (TOC) test in wastewater and sodium chloride: TOC content in waste water or byproduct sodium chloride is measured by a total organic carbon total bonding nitrogen analyzer MultiN/C3100, and the test principle is that after a water sample is injected into a high temperature area of a combustion furnace, the water sample is catalyzed and oxidized under the action of a catalyst and oxygen to be finally decomposed into CO 2 After drying, the mixture enters an NDIR detector to detect and obtain CO 2 And finally, obtaining the TOC value of the sample to be detected through conversion. For the wastewater sample, the sample needs to be diluted by 10 times by purified water and then injected, and for the byproduct salt sample, the sample needs to be diluted by 50 times and then injected.
PPS fiber ball poreThe rate characterization method comprises the following steps: measuring the diameter of the fiber ball, recording the radius as r (unit cm), taking a 100mL measuring cylinder, adding 60mL of water, completely immersing the fiber ball in the water in the measuring cylinder, and reading the volume V at the moment 1 Porosity of the fiber ball
Preparation of PPS fiber balls
Example 1
And braiding 60 bundles of 10k PPS long fiber tows into a large bundle, wherein the fineness of the PPS fibers is 2D, winding and knotting the polyester fiber tows every 4cm, cutting off the fiber tows at the central positions of two adjacent knotting points, slightly finishing to obtain fiber balls with the diameters of about 3.8cm, wherein the diameters of the fiber balls are approximately stretched along the diameter direction, and the porosities of the fiber balls are measured to be about 65%.
Example 2
And braiding 20 bundles of 10k PPS long fiber tows into a large bundle, wherein the fineness of the PPS fibers is 2D, winding and knotting the polyester fiber tows every 4cm, cutting off the fiber tows at the central positions of two adjacent knotting points, and slightly finishing to obtain fiber balls with the diameters of about 3.7cm, wherein the diameters of the fiber balls are approximately stretched along the diameter direction, and the porosity of the fiber balls is measured to be about 90%.
Preparation method of methyl methacrylate-acrylic acid-styrene-divinylbenzene copolymerized macroporous resin
Example 3
Into a 1L three-neck flask, 450g of aqueous phase (containing 5g of PVA and 445g of distilled water) is added, the mixture is stirred uniformly, 150g of oil phase (75 g of n-heptane, 10.84g of methyl methacrylate, 57.9g of styrene, 1.56 g of acrylic acid and 4.7g of divinylbenzene, namely the molar ratio of the comonomers is 15:77:3:5 in sequence), the rotating speed is regulated to 100r/min, 1.5g of free radical initiator Azobisisobutyronitrile (AIBN) is added, and the mixture is heated to 75 ℃ for reaction for 6 hours. Filtering out the resin after polymerization, sequentially leaching with hot water and absolute ethyl alcohol for multiple times, performing Soxhlet extraction with absolute acetone for 6 hours, and finally washing with distilled water and soaking for later use. The obtained macroporous resin has an average pore diameter of 12nm and a specific surface area of 100m 2 /g。
Example 4
450g of aqueous phase (containing 5g of PVA and 445g of distilled water) is added into a 1L three-neck flask, stirred uniformly, 150g of oil phase (75 g of n-heptane, 3.62g of methyl methacrylate, 64.06g of styrene, 2.61g of acrylic acid and 4.71g of divinylbenzene, namely the molar ratio of the comonomers is 5:85:5:5 in sequence) is added, the rotating speed is adjusted to 100r/min, 1.5g of free radical initiator AIBN is added, and the temperature is raised to 75 ℃ for reaction for 6 hours. Filtering out the resin after polymerization, sequentially leaching with hot water and absolute ethyl alcohol for multiple times, performing Soxhlet extraction with absolute acetone for 6 hours, and finally washing with distilled water and soaking for later use. The obtained macroporous resin has an average pore diameter of 10.5nm and a specific surface area of 90m 2 /g。
Example 5
19.8kg (200.0 mol) of N-methyl pyrrolidone and 10.0kg (100.0 mol) of 40% sodium hydroxide are added into a 100L reaction kettle, and the mixture is heated to 120 ℃ at a speed of 2.0 ℃/min under the stirring speed of 300rpm and the protection of nitrogen, and the temperature is kept for 1 hour; after the heat preservation, the temperature is raised to 200 ℃ at the speed of 2.0 ℃/min, 5.8kg of water solution (the water content is 98.0%) is removed, and then the temperature is reduced to 130 ℃. 14.02Kg (100.0 mol) of 40% sodium hydrosulfide, 4.95Kg (50 mol) of NMP, were added, the temperature was raised to 200℃at a rate of 1.5℃per minute under the same stirring, 6.74Kg of aqueous solution (water content 98.0%) was removed, and after dehydration, the temperature was lowered to 160 ℃. At this time, the amount of sulfur in the system was 98.0mol and the water content was 117.6mol.
15.14kg (103.0 mol) of paradichlorobenzene and 4.95kg (104.8 mol) of NMP are added into the reaction kettle, the temperature is raised to 260 ℃ at the speed of 1.0 ℃/min, the mixture is kept for 3 hours, and then flash evaporation is carried out in a flash evaporation tank within 0.5-1.0 hour, and the superheated nitrogen at 260 ℃ is continuously introduced in the flash evaporation process. After the flash evaporation is finished, the mixture is dried for 1 hour under the nitrogen atmosphere, NMP is fully removed, and the drying temperature is 240 ℃.
The dried flash crude product was washed 2 times with deionized water, 45kg each time with water, and the two washing filtrates were mixed. And drying the washed filter cake to obtain white polyphenylene sulfide crosslinked raw powder PPS-19.72kg, and testing the melt flow rate to be 3500g/10min. And (3) placing the crosslinked raw powder into a crosslinking bin with a stirring, dedusting bag and a heat conducting oil jacket, introducing crosslinking gas with the oxygen content of 12% at 240 ℃ for 12 hours to obtain a PPS crosslinked product CPPS-1, and testing the MFR to be 500g/10min.
The above twice-washed wastewater was filtered using a precision filter (filter cloth 3000 mesh) to obtain filtrate I, in which the content of CP-SMAB was 1500ppm, the content of 4-chloro-N-methylaniline was 325ppm, and the TOC test of wastewater was 2800ppm by liquid phase analysis. Adding hydrochloric acid into the filtrate I to adjust the pH to 4, enabling the wastewater to become turbid and the turbidity to be 350NTU, filtering by using a filter filled with PPS fiber balls prepared in the embodiment 1, filtering acid-adjusting precipitates, enabling the turbidity of the wastewater to be reduced to 10NTU, enabling the TOC to be reduced to 1600ppm, bubbling and purging the wastewater by nitrogen in a bubbler, adding a small amount of sodium hydroxide to adjust the pH of the wastewater to 5, and then adsorbing by using a filling column of macroporous resin prepared in the embodiment 3, wherein the TOC of the wastewater after resin adsorption is reduced to 250ppm. And the waste water after adsorption is adjusted to be neutral, and concentrated and steamed to obtain waste salt and condensed water, wherein TOC test values of the waste salt and the condensed water are 800ppm and 160ppm respectively, the byproduct sodium chloride has excellent quality, and the condensed water can be used as washing water. The TOC and typical organic content of the wastewater in each stage are shown in Table 1.
Example 6
Hydrochloric acid is added into filtrate I in example 5 to adjust the pH to 4, the wastewater becomes turbid and has turbidity of 350NTU, then a filter filled with PPS fiber balls prepared in example 2 is used for filtering, acid-adjusting precipitates are filtered, the turbidity of the wastewater is reduced to 30NTU, the TOC is reduced to 1900ppm, then nitrogen is used for bubbling and purging the wastewater in a bubbler, a small amount of sodium hydroxide is added to finely adjust the pH of the wastewater to 5, then the packed column of macroporous resin prepared in example 3 is used for adsorption, and the TOC of the wastewater after resin adsorption is reduced to 290ppm. And regulating the waste water after adsorption to be neutral, concentrating, evaporating to obtain waste salt and condensed water, wherein TOC test values of the waste salt and the condensed water are 1060ppm and 165ppm respectively.
Example 7
Hydrochloric acid is added into filtrate I in example 5 to adjust the pH to 4, the wastewater becomes turbid and has turbidity of 350NTU, then a filter filled with PPS fiber balls prepared in example 1 is used for filtering, acid-adjusting precipitates are filtered, the turbidity of the wastewater is reduced to 10NTU, the TOC is reduced to 1600ppm, then nitrogen is used for bubbling and purging the wastewater in a bubbler, a small amount of sodium hydroxide is added to finely adjust the pH of the wastewater to 5, then the packed column of macroporous resin prepared in example 4 is used for adsorption, and the TOC of the wastewater after resin adsorption is reduced to 400ppm. And regulating the waste water after adsorption to be neutral, concentrating, evaporating to obtain waste salt and condensed water, wherein TOC test values of the waste salt and the condensed water are 1640ppm and 200ppm respectively.
Example 8
Hydrochloric acid is added into filtrate I in example 5 to adjust the pH to 2.5, the wastewater becomes turbid and has turbidity of 280NTU, then a filter filled with PPS fiber balls prepared in example 1 is used for filtering, acid-adjusting precipitate is filtered, the turbidity of the wastewater is reduced to 10NTU, TOC is reduced to 2050ppm, then nitrogen is used for bubbling and purging the wastewater in a bubbler, a small amount of sodium hydroxide is added to finely adjust the pH of the wastewater to 5, then the wastewater is adsorbed by a packed column of macroporous resin prepared in example 3, and TOC of the wastewater after resin adsorption is reduced to 300ppm. And regulating the waste water after adsorption to be neutral, concentrating, evaporating to obtain waste salt and condensed water, wherein TOC test values of the waste salt and the condensed water are 1100ppm and 170ppm respectively.
Example 9
Hydrochloric acid is added into filtrate I in example 5 to adjust the pH to 4, the wastewater becomes turbid and has turbidity of 350NTU, then the filter filled with PPS fiber balls prepared in example 1 is used for filtering, acid-adjusting precipitate is filtered, the turbidity of the wastewater is reduced to 10NTU, the TOC is reduced to 1600ppm, then nitrogen is used for bubbling and purging the wastewater in a bubbler, a small amount of sodium hydroxide is added to adjust the pH of the wastewater to 8, then the packed column of macroporous resin prepared in example 3 is used for adsorption, and the TOC of the wastewater after resin adsorption is reduced to 350ppm. And regulating the waste water after adsorption to be neutral, concentrating, evaporating to obtain waste salt and condensed water, wherein TOC test values of the waste salt and the condensed water are 1340ppm and 190ppm respectively.
Example 10
9.8Kg (200.0 mol) of N-methyl pyrrolidone and 10.2Kg (102.0 mol) of 40% sodium hydroxide are added into a 100L reaction kettle, and the mixture is heated to 120 ℃ at a speed of 2.0 ℃/min under the stirring speed of 300rpm and the protection of nitrogen, and the temperature is kept for 1 hour; after the heat preservation, the temperature is raised to 200 ℃ at the speed of 2.0 ℃/min, 5.8kg of water solution (the water content is 98.0%) is removed, and then the temperature is reduced to 130 ℃. 14.02kg (100.0 mol) of 40% sodium hydrosulfide, 4.95kg (50 mol) of NMP, were added, the temperature was raised to 200℃at a rate of 1.5℃per minute under the same stirring, 6.74kg of an aqueous solution (water content 98.0%) was removed, and after dehydration, the temperature was lowered to 160 ℃. At this time, the amount of sulfur in the system was 98.0mol and the water content was 117.6mol.
4.85kg (101.0 mol) of paradichlorobenzene and 4.95kg (104.8 mol) of NMP are added into the reaction kettle, the temperature is raised to 260 ℃ at the speed of 1.0 ℃/min, the mixture is kept for 3 hours, and then flash evaporation is carried out in a flash evaporation tank within 0.5-1.0 hour, and the superheated nitrogen at 260 ℃ is continuously introduced in the flash evaporation process. After the flash evaporation is finished, the mixture is dried for 1 hour under the nitrogen atmosphere, NMP is fully removed, and the drying temperature is 240 ℃.
The dried flash crude product was washed 2 times with deionized water, 45kg each time with water, and the two washing filtrates were mixed. And drying the washed filter cake to obtain white polyphenylene sulfide crosslinked raw powder PPS-29.94kg, and testing the melt flow rate to be 1500g/10min. And (3) placing the crosslinked raw powder into a crosslinking bin with a stirring, dedusting bag and a heat conducting oil jacket, introducing crosslinking gas with the oxygen content of 12% at 240 ℃ for 12 hours to obtain a PPS crosslinked product CPPS-2, and testing the MFR to be 300g/10min.
The twice washed wastewater was filtered using a fine filter with 3000 mesh filter cloth to obtain filtrate I, and the filtrate I was measured by liquid phase analysis to have a CP-SMAB content of 2000ppm, a 4-chloro-N-methylaniline content of 350ppm, and a wastewater TOC test of 3200ppm. Adding hydrochloric acid into the filtrate I to adjust the pH to 4, enabling the wastewater to become turbid and have turbidity of 400NTU, filtering by using a filter filled with PPS fiber balls prepared in the embodiment 1, filtering acid-adjusting precipitates, enabling the turbidity of the wastewater to be reduced to 10NTU, enabling the TOC to be reduced to 1800ppm, bubbling and purging the wastewater by nitrogen in a bubbler, adding a small amount of sodium hydroxide to adjust the pH of the wastewater to 5, and then adsorbing by using a filling column of macroporous resin prepared in the embodiment 3, wherein the TOC of the wastewater after resin adsorption is reduced to 260ppm. And the waste water after adsorption is adjusted to be neutral, and concentrated and steamed to obtain waste salt and condensed water, wherein TOC test values of the waste salt and the condensed water are 875ppm and 160ppm respectively, the byproduct sodium chloride has excellent quality, and the condensed water can be used as washing water.
Comparative example 1
The filtrate I in example 5 was added with hydrochloric acid to adjust ph=4, then filtered again using a fine filter (filter cloth 3000 mesh), turbidity was reduced from 350NTU to 300NTU, TOC was reduced from 2800ppm to 2600ppm, then the wastewater was bubbled with nitrogen in a bubbler, and after the pH of the wastewater was fine-tuned to 5 with a small amount of sodium hydroxide, adsorption was performed using a packed column of the macroporous resin prepared in example 3, and TOC of the wastewater after resin adsorption was reduced to 460ppm. And (3) regulating the waste water after adsorption to be neutral, concentrating, evaporating to obtain waste salt and condensed water, wherein TOC test values of the waste salt and the condensed water are 2040 ppm and 195ppm respectively.
Comparative example 2
The filtrate I in example 5 was added with hydrochloric acid to adjust ph=4, and then filtered again using a fine filter (filter cloth 3000 mesh), turbidity was reduced from 350NTU to 300NTU, TOC was reduced from 2800ppm to 2600ppm, then the wastewater was bubbled with nitrogen in a bubbler, and after the wastewater was brought to neutral, the salt was evaporated by concentration to obtain waste salt and condensed water, and TOC test values of waste salt and condensed water were 14600ppm and 550ppm, respectively.
Comparative example 3
Hydrochloric acid is added into filtrate I in example 5 to adjust the pH to 4, the wastewater becomes turbid and has turbidity of 350NTU, then a filter filled with PPS fiber balls prepared in example 1 is used for filtering, acid-adjusting precipitates are filtered, the turbidity of the wastewater is reduced to 10NTU, the TOC is reduced to 1600ppm, then nitrogen is used for bubbling and purging the wastewater in a bubbler, the wastewater is neutralized, and then concentrated and steamed to obtain waste salt and condensed water, wherein TOC test values of the waste salt and the condensed water are 9600ppm and 300ppm respectively.
Comparative example 4
After the filtrate I in example 5 was adjusted to ph=4, the wastewater was bubbled with nitrogen in a bubbler, and then a small amount of sodium hydroxide was added to fine-adjust the pH of the wastewater to 5, and then adsorption was performed using the packed column of the macroporous resin prepared in example 3, and the TOC of the wastewater after resin adsorption was reduced to 500ppm. And (3) regulating the wastewater to be neutral after adsorption, concentrating and evaporating salt to obtain waste salt and condensed water, wherein TOC test values of the waste salt and the condensed water are 2320ppm and 220ppm respectively.
Claims (9)
1. A method for treating a polyphenylene sulfide reaction solution is characterized by comprising the following steps:
(1) The polyphenylene sulfide reaction liquid is subjected to flash evaporation to obtain a solid, then the solid is washed by deionized water, the washed solid is dried to obtain a polyphenylene sulfide product, washing wastewater obtained after washing is filtered to remove PPS fine particles, then acidification is carried out, and a filter filled with PPS fiber balls is used for filtering to obtain filtered acidic wastewater;
(2) Blowing the acidic wastewater obtained in the step (1) to remove hydrogen sulfide, then adopting methyl methacrylate-acrylic acid-styrene-divinylbenzene copolymerized macroporous resin to adsorb, concentrating and distilling the adsorbed wastewater to obtain sodium chloride and recovered condensed water;
the polyphenylene sulfide reaction liquid is obtained by carrying out solution polycondensation reaction on a sulfur-containing compound and paradichlorobenzene;
in the step (2), the pH value of the waste water after stripping is adjusted to be between 5 and 9, and then adsorption is carried out.
2. The method for treating a polyphenylene sulfide reaction solution according to claim 1, wherein in the step (1), the fine particles of PPS are removed by filtration using a fine filter having a filtration mesh number of 1000 to 7500 mesh.
3. The method for treating a polyphenylene sulfide reaction solution according to claim 1, wherein in the step (1), the pH of the waste water after acidification is 2 to 5.
4. The method for treating a polyphenylene sulfide reaction solution according to claim 3, wherein the pH of the waste water after acidification is 2 to 4, and the acid used for acidification is hydrochloric acid.
5. The method for treating a polyphenylene sulfide reaction solution according to claim 1, wherein in the step (1), the PPS fiber balls are balls obtained by spinning PPS fibers, and the porosity is 50 to 95%.
6. The method for treating a polyphenylene sulfide reaction solution according to claim 5, wherein the fineness of the PPS fiber is 0.5 to 4 denier.
7. The method for treating a polyphenylene sulfide reaction solution according to claim 1, wherein in the step (2), the methyl methacrylate-acrylic acid-styrene-divinylbenzene copolymerized macroporous resin is prepared by suspension polymerization, and the molar ratio of methyl methacrylate monomer, acrylic acid monomer, styrene monomer and divinylbenzene monomer in the raw materials is 5-30: 1 to 5: 60-90: 1 to 10.
8. The method for treating a polyphenylene sulfide reaction solution according to claim 1, wherein in the step (2), the methyl methacrylate-acrylic acid-styrene-divinylbenzene copolymerized macroporous resin has an average pore diameter of 10 to 15nm and a specific surface area of 90 to 150m 2 /g。
9. The clean production process of the polyphenylene sulfide is characterized by comprising the following steps of:
carrying out solution polycondensation reaction on a sulfur-containing compound and paradichlorobenzene to obtain a polyphenylene sulfide reaction solution, and treating the polyphenylene sulfide reaction solution according to the treatment method of any one of claims 1-8 to obtain a polyphenylene sulfide product and sodium chloride as a byproduct.
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