CN110642887B - Continuous production method of hydroxyethylidene diphosphonic acid crystal - Google Patents
Continuous production method of hydroxyethylidene diphosphonic acid crystal Download PDFInfo
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- 239000013078 crystal Substances 0.000 title claims abstract description 46
- BAERPNBPLZWCES-UHFFFAOYSA-N (2-hydroxy-1-phosphonoethyl)phosphonic acid Chemical compound OCC(P(O)(O)=O)P(O)(O)=O BAERPNBPLZWCES-UHFFFAOYSA-N 0.000 title claims abstract description 44
- 238000000034 method Methods 0.000 title claims abstract description 27
- 238000010924 continuous production Methods 0.000 title claims abstract description 6
- 238000002425 crystallisation Methods 0.000 claims abstract description 90
- 230000008025 crystallization Effects 0.000 claims abstract description 85
- 239000000463 material Substances 0.000 claims abstract description 55
- 239000007788 liquid Substances 0.000 claims abstract description 42
- 239000000047 product Substances 0.000 claims abstract description 27
- 238000001816 cooling Methods 0.000 claims abstract description 26
- 230000000694 effects Effects 0.000 claims abstract description 25
- 238000003756 stirring Methods 0.000 claims abstract description 24
- 238000000926 separation method Methods 0.000 claims abstract description 16
- 238000001035 drying Methods 0.000 claims abstract description 10
- 239000012263 liquid product Substances 0.000 claims abstract description 9
- 238000005086 pumping Methods 0.000 claims abstract description 8
- 239000012452 mother liquor Substances 0.000 claims description 20
- 238000000746 purification Methods 0.000 claims description 5
- 238000001704 evaporation Methods 0.000 claims description 3
- 230000008020 evaporation Effects 0.000 claims description 3
- 238000010438 heat treatment Methods 0.000 claims description 3
- 238000004064 recycling Methods 0.000 claims description 3
- 238000004821 distillation Methods 0.000 abstract description 22
- 238000009776 industrial production Methods 0.000 abstract description 3
- 238000009833 condensation Methods 0.000 abstract description 2
- 230000005494 condensation Effects 0.000 abstract description 2
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 12
- DBVJJBKOTRCVKF-UHFFFAOYSA-N Etidronic acid Chemical compound OP(=O)(O)C(O)(C)P(O)(O)=O DBVJJBKOTRCVKF-UHFFFAOYSA-N 0.000 description 9
- VEXZGXHMUGYJMC-UHFFFAOYSA-M Chloride anion Chemical compound [Cl-] VEXZGXHMUGYJMC-UHFFFAOYSA-M 0.000 description 7
- 238000004519 manufacturing process Methods 0.000 description 7
- QTBSBXVTEAMEQO-UHFFFAOYSA-N Acetic acid Chemical compound CC(O)=O QTBSBXVTEAMEQO-UHFFFAOYSA-N 0.000 description 6
- 239000012535 impurity Substances 0.000 description 6
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 description 5
- 238000007599 discharging Methods 0.000 description 5
- IXCSERBJSXMMFS-UHFFFAOYSA-N hydrogen chloride Substances Cl.Cl IXCSERBJSXMMFS-UHFFFAOYSA-N 0.000 description 5
- 229910000041 hydrogen chloride Inorganic materials 0.000 description 5
- 238000001556 precipitation Methods 0.000 description 5
- 239000007787 solid Substances 0.000 description 5
- 230000009286 beneficial effect Effects 0.000 description 4
- 238000006243 chemical reaction Methods 0.000 description 4
- 230000000052 comparative effect Effects 0.000 description 4
- 239000000498 cooling water Substances 0.000 description 4
- 230000007613 environmental effect Effects 0.000 description 4
- 239000011229 interlayer Substances 0.000 description 4
- 239000002994 raw material Substances 0.000 description 4
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 3
- 238000005119 centrifugation Methods 0.000 description 3
- 125000004122 cyclic group Chemical group 0.000 description 3
- 239000010439 graphite Substances 0.000 description 3
- 229910002804 graphite Inorganic materials 0.000 description 3
- 230000005764 inhibitory process Effects 0.000 description 3
- 238000002347 injection Methods 0.000 description 3
- 239000007924 injection Substances 0.000 description 3
- 229910052751 metal Inorganic materials 0.000 description 3
- 239000002184 metal Substances 0.000 description 3
- 239000002245 particle Substances 0.000 description 3
- 238000002360 preparation method Methods 0.000 description 3
- 239000012265 solid product Substances 0.000 description 3
- 239000000126 substance Substances 0.000 description 3
- VTYYLEPIZMXCLO-UHFFFAOYSA-L Calcium carbonate Chemical compound [Ca+2].[O-]C([O-])=O VTYYLEPIZMXCLO-UHFFFAOYSA-L 0.000 description 2
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 2
- UQSXHKLRYXJYBZ-UHFFFAOYSA-N Iron oxide Chemical compound [Fe]=O UQSXHKLRYXJYBZ-UHFFFAOYSA-N 0.000 description 2
- YDONNITUKPKTIG-UHFFFAOYSA-N [Nitrilotris(methylene)]trisphosphonic acid Chemical compound OP(O)(=O)CN(CP(O)(O)=O)CP(O)(O)=O YDONNITUKPKTIG-UHFFFAOYSA-N 0.000 description 2
- 238000009835 boiling Methods 0.000 description 2
- 238000004140 cleaning Methods 0.000 description 2
- 230000007797 corrosion Effects 0.000 description 2
- 238000005260 corrosion Methods 0.000 description 2
- 238000001953 recrystallisation Methods 0.000 description 2
- 238000010025 steaming Methods 0.000 description 2
- 239000002699 waste material Substances 0.000 description 2
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 1
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 description 1
- OAICVXFJPJFONN-UHFFFAOYSA-N Phosphorus Chemical compound [P] OAICVXFJPJFONN-UHFFFAOYSA-N 0.000 description 1
- VMHLLURERBWHNL-UHFFFAOYSA-M Sodium acetate Chemical compound [Na+].CC([O-])=O VMHLLURERBWHNL-UHFFFAOYSA-M 0.000 description 1
- HCHKCACWOHOZIP-UHFFFAOYSA-N Zinc Chemical compound [Zn] HCHKCACWOHOZIP-UHFFFAOYSA-N 0.000 description 1
- 230000032683 aging Effects 0.000 description 1
- 229910052785 arsenic Inorganic materials 0.000 description 1
- 239000012752 auxiliary agent Substances 0.000 description 1
- 229910000019 calcium carbonate Inorganic materials 0.000 description 1
- 239000001506 calcium phosphate Substances 0.000 description 1
- 229910000389 calcium phosphate Inorganic materials 0.000 description 1
- 235000011010 calcium phosphates Nutrition 0.000 description 1
- 238000012824 chemical production Methods 0.000 description 1
- 239000003795 chemical substances by application Substances 0.000 description 1
- 239000008139 complexing agent Substances 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
- 239000012141 concentrate Substances 0.000 description 1
- 229910052802 copper Inorganic materials 0.000 description 1
- 239000010949 copper Substances 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 230000018044 dehydration Effects 0.000 description 1
- 238000006297 dehydration reaction Methods 0.000 description 1
- 239000002270 dispersing agent Substances 0.000 description 1
- 239000003814 drug Substances 0.000 description 1
- 230000000668 effect on calcium Effects 0.000 description 1
- 238000009713 electroplating Methods 0.000 description 1
- 239000012467 final product Substances 0.000 description 1
- 239000012847 fine chemical Substances 0.000 description 1
- 230000002431 foraging effect Effects 0.000 description 1
- 239000007789 gas Substances 0.000 description 1
- 230000005484 gravity Effects 0.000 description 1
- 239000003112 inhibitor Substances 0.000 description 1
- 150000002500 ions Chemical class 0.000 description 1
- 229910052742 iron Inorganic materials 0.000 description 1
- 230000001788 irregular Effects 0.000 description 1
- 238000011031 large-scale manufacturing process Methods 0.000 description 1
- 229910021645 metal ion Inorganic materials 0.000 description 1
- 239000000178 monomer Substances 0.000 description 1
- 239000010413 mother solution Substances 0.000 description 1
- 239000002667 nucleating agent Substances 0.000 description 1
- 238000002161 passivation Methods 0.000 description 1
- 229910052698 phosphorus Inorganic materials 0.000 description 1
- 239000011574 phosphorus Substances 0.000 description 1
- CYQAYERJWZKYML-UHFFFAOYSA-N phosphorus pentasulfide Chemical compound S1P(S2)(=S)SP3(=S)SP1(=S)SP2(=S)S3 CYQAYERJWZKYML-UHFFFAOYSA-N 0.000 description 1
- FAIAAWCVCHQXDN-UHFFFAOYSA-N phosphorus trichloride Chemical compound ClP(Cl)Cl FAIAAWCVCHQXDN-UHFFFAOYSA-N 0.000 description 1
- 239000000843 powder Substances 0.000 description 1
- 239000001632 sodium acetate Substances 0.000 description 1
- 235000017281 sodium acetate Nutrition 0.000 description 1
- 239000000243 solution Substances 0.000 description 1
- QORWJWZARLRLPR-UHFFFAOYSA-H tricalcium bis(phosphate) Chemical compound [Ca+2].[Ca+2].[Ca+2].[O-]P([O-])([O-])=O.[O-]P([O-])([O-])=O QORWJWZARLRLPR-UHFFFAOYSA-H 0.000 description 1
- 229910052725 zinc Inorganic materials 0.000 description 1
- 239000011701 zinc Substances 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07F—ACYCLIC, CARBOCYCLIC OR HETEROCYCLIC COMPOUNDS CONTAINING ELEMENTS OTHER THAN CARBON, HYDROGEN, HALOGEN, OXYGEN, NITROGEN, SULFUR, SELENIUM OR TELLURIUM
- C07F9/00—Compounds containing elements of Groups 5 or 15 of the Periodic Table
- C07F9/02—Phosphorus compounds
- C07F9/28—Phosphorus compounds with one or more P—C bonds
- C07F9/38—Phosphonic acids [RP(=O)(OH)2]; Thiophosphonic acids ; [RP(=X1)(X2H)2(X1, X2 are each independently O, S or Se)]
- C07F9/3804—Phosphonic acids [RP(=O)(OH)2]; Thiophosphonic acids ; [RP(=X1)(X2H)2(X1, X2 are each independently O, S or Se)] not used, see subgroups
- C07F9/3808—Acyclic saturated acids which can have further substituents on alkyl
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- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Health & Medical Sciences (AREA)
- Life Sciences & Earth Sciences (AREA)
- Biochemistry (AREA)
- General Health & Medical Sciences (AREA)
- Molecular Biology (AREA)
Abstract
The invention provides a continuous production method of hydroxyethylidene diphosphonic acid crystal. The specific operation method comprises the following steps: preheating a hydroxyethylidene diphosphonic acid liquid product with the activity content of 50-65%, carrying out gas-liquid separation, and then continuously pumping the liquid product into a distillation kettle at a constant speed; distilling and concentrating until the active content of the material is more than or equal to 70%, condensing the high-temperature material, automatically transferring the material step by step between crystallization kettles connected in series at the tail, and carrying out continuous crystallization step by step under the conditions of stirring and natural cooling; finally, the temperature is reduced by circulating condensation in an nth-stage crystallization kettle, and the temperature of the system is maintained at 20 +/-2 ℃. After full crystallization, the hydroxyl ethylidene diphosphonic acid crystal product with the activity content of more than or equal to 98 percent is obtained through separation and drying treatment. The traditional single-kettle closed crystallization method is changed into an industrial production line crystallization method, the prepared crystal has proper granularity, no crystallization promoter and crystal nucleus are added in the crystallization process, no decrepitation exists, and the method is suitable for industrialization.
Description
Technical Field
The invention belongs to the technical field of fine chemical production, and particularly relates to a continuous production method of hydroxyethylidene diphosphonic acid crystals.
Background
The hydroxyethylidene diphosphonic acid (HEDP for short) has extremely stable C-P bond in the molecule, the bond energy is 246kJ/mol, and the hydroxyethylidene diphosphonic acid has high temperature resistance, has good scale inhibition effect on calcium carbonate, hydrated iron oxide and calcium phosphate in water and is an important scale inhibition dispersant. Because HEDP can form stable complex with iron, copper, zinc and other metal ions, the HEDP can dissolve oxides on the surface of metal and can be used as a complexing agent in the cyanide-free electroplating industry; in addition, because the HEDP has better corrosion and scale inhibition effects and a passivation effect on the metal surface, the high-purity HEDP product can be used for cleaning circuit boards in the electronic industry and treating the metal surface.
The conventional commercially available 50% or 60% specification HEDP liquid product is synthesized by taking phosphorus trichloride as one of starting raw materials, and various impurities associated in the raw materials greatly limit the application of the HEDP liquid product in the industries of electronic cleaning, medicine and daily chemical industry, so that the research and production of HEDP crystals or solid products with higher purity are realized, the additional value of the product is improved, and the method becomes a technical hotspot concerned by researchers in the field. Chinese patent CN1312163C discloses a method for preparing a solid hydroxyethylidene diphosphonic acid product with the content of more than or equal to 90% by using 50-60% of liquid hydroxyethylidene diphosphonic acid as a raw material, adding crystal nucleus sodium acetate and a crystallization promoter absolute ethyl alcohol, slowly stirring for crystallization in a reaction kettle, standing for aging, and centrifugally drying. The patent of CN101597305B discloses a preparation process of high-purity solid amino trimethylene phosphonic acid or hydroxy ethylidene diphosphonic acid, which comprises the steps of controlling the liquid temperature of amino trimethylene phosphonic acid or hydroxy ethylidene diphosphonic acid with 68-85% of effective substance content at 30-90 ℃, then adding ice crystal particles into a liquid system to precipitate crystals, and obtaining corresponding solid products through centrifugal dehydration and drying at 60-120 ℃. CN107522740A relates to a production process of low-arsenic solid hydroxyethylidene diphosphonic acid, which comprises the steps of in a reaction kettle, carrying out cyclic dearsenization treatment on hydroxyethylidene diphosphonic acid liquid by utilizing a dearsenization agent phosphorus pentasulfide, then concentrating, heating and gradually raising the temperature to remove water, adding a nucleating agent into a discharge chute, gradually reducing the material temperature, and preparing an HEDP solid product with the activity of more than or equal to 98% by adopting a natural crystallization mode. The present inventors disclose in CN100478347C a preparation process suitable for electronic grade solid hydroxyethylidene diphosphonic acid.
The prior published preparation methods of hydroxyethylidene diphosphonic acid solid or crystal all adopt the traditional intermittent single kettle type operation, which is not beneficial to the stability of the product quality among batches; meanwhile, because the crystallization process is a slow physical process influenced by multiple factors, the equipment occupation period is long, the capacity scale of the product is greatly limited, and the market application and popularization of the product are seriously influenced.
Disclosure of Invention
In order to solve the problems and the defects in the prior art, the invention provides a production method capable of continuously producing hydroxyethylidene diphosphonic acid crystals. The method adopts a multistage crystallization mode through natural cooling and crystallization of the hydroxyethylidene diphosphonic acid, can effectively stabilize the product quality, improve the equipment utilization rate and the product yield, save water, reduce emission, avoid three wastes, is safe and environment-friendly, and is beneficial to realizing automatic control and large-scale industrial production.
The invention is realized by the following technical scheme:
a continuous production method of hydroxyethylidene diphosphonic acid crystals specifically comprises the following steps:
(1) preheating a hydroxyethylidene diphosphonic acid liquid product with the activity content of 50-65%, carrying out gas-liquid separation, and then continuously pumping the liquid product into a distillation kettle at a constant speed;
(2) when the material in the distillation kettle reaches one third of the volume of the kettle body, starting stirring and rapidly raising the temperature, and establishing a negative pressure condition of-0.04 to-0.06 MPa for continuous concentration and purification;
(3) when the volume of the materials in the concentration kettle is more than or equal to three-quarters of the volume of the kettle and the active content of the materials is more than or equal to 70 percent, the high-temperature materials are cooled and then sequentially and automatically transferred step by step between 1-n stages of crystallization kettles connected in series end to end, and are subjected to continuous crystallization step by step under the conditions of stirring and natural cooling;
(4) and (3) circularly condensing the mixed material in the nth-stage crystallization kettle again to reduce the temperature and maintain the system temperature at 20 +/-2 ℃ so that the system is fully crystallized, centrifuging and drying the mixed material to obtain a hydroxyethylidene diphosphonic acid crystal product with the activity content of more than or equal to 98%, and collecting and recycling mother liquor obtained by separation.
The temperature range of the preheated liquid in the step (1) is 60-100 ℃, and preferably, the temperature of the preheated liquid is 75-90 ℃.
The separation in the step (1) is to separate the preheated material by a gas-liquid separator to remove low-boiling-point hydrogen chloride and a small amount of water vapor carried in the product, and the high-boiling-point substance continuously enters the distillation concentration kettle through the bottom of the gas-liquid separator.
The concentration temperature in the step (2) may be 110 to 150 ℃, and preferably, the concentration temperature is 120 to 130 ℃.
The concentration and purification in the step (2) refers to that the mixed gas in the kettle enters the gas-liquid separator again for separation to remove water and acetic acid impurities contained in the product when the material is concentrated at high temperature.
The lower boiling point component obtained by the separation and purification in the step (1) and the step (2) can be recycled to be used as a raw material for producing liquid products after being cooled and recovered.
And (4) the temperature of the condensed material in the step (3) is 60-70 ℃.
And (4) automatically transferring the mixed material in the step (3) through a PLC automatic interlocking device established between a liquid level meter arranged in the 1-n-grade crystallization kettle and a kettle top feeding valve and a kettle bottom discharging valve.
The number of the crystallization kettles connected in series end to end in the step (3) is more than or equal to 2 and less than or equal to 8, and preferably, n = 3-5.
The gradient range of natural cooling in the 1-n grade crystallization kettle in the step (3) is 5-20 ℃/grade, the preferred gradient range of natural cooling in the 1-2 grade crystallization kettle is 5-10 ℃/grade, and the gradient range of natural cooling in the 3-n grade crystallization kettle is 10-20 ℃/grade.
Wherein the stirring speed in the 1 st-stage crystallization kettle is 80-150 rpm, and the stirring speed of the 1-n crystallization kettle is gradually reduced.
And (4) continuously pumping the mother liquor in the step (4) into a distillation concentration device for concentration and then circularly using for recrystallization step by step, wherein the mother liquor can be used as a compound phosphorus-containing scale and corrosion inhibitor monomer when the chroma is more than or equal to 180 Hazen.
The invention concentrates and removes impurities at high temperature, cools to 60-70 ℃ to form supersaturated solution, and coagulates crystal nucleus in the first and second reaction kettles by using the concentration of polar region by changing the environmental parameters in the crystallization kettle, thereby ensuring no sudden precipitation and no pipeline blockage. In the subsequent crystallization kettle, the environmental parameters are changed again, so that the crystal grows instead of continuously nucleating, and small crystal nuclei which are not easy to separate grow into crystal grains with proper size. In the last stage of crystallization kettle, the circulating condensation is reduced to low temperature, so that the product in water is separated out as much as possible, and the maximum yield is ensured.
The invention changes the constant-speed cooling and crystal seed adding even crystallization accelerator closed crystallization kettle crystallization in the prior art into multi-crystallization kettle assembly line continuous operation, does not add any auxiliary agent and crystal nucleus in the middle, adjusts a crystal metastable zone through the multi-crystallization kettle with different environmental parameters, prevents sudden precipitation and obtains crystal grains with proper size, and does not need to introduce impurities such as crystal nucleus, crystal accelerator and the like.
The invention has the beneficial effects that:
(1) according to the invention, through controlling the environmental parameters of the crystallization kettles connected in series at all levels, the industrial production line continuous crystallization and the mother liquor continuous cyclic utilization of the hydroxyethylidene diphosphonic acid crystal are realized, the production efficiency is improved, and the product quality is stable;
(2) the method utilizes the gravity settling effect to separate and purify liquid products in the preheating stage and the distillation concentration stage respectively, removes impurities with relatively low boiling points such as hydrogen chloride, acetic acid and the like and redundant moisture in the products, effectively realizes the rapid separation and purification of materials, and shortens the production period;
(3) the cooling gradient of 5-20 ℃/level is realized in the multi-level continuous crystallization process, the last level of cooling is adopted to realize full crystallization, and the product yield can reach more than 90%;
(4) in the multistage continuous crystallization process, crystal nucleus and a crystal promoter are not used, new impurities are not introduced, and the final product has high purity;
(5) the heat exchange among the system materials is facilitated in the process of recycling the mother liquor, and the temperature of a crystallization system is facilitated to be reduced;
(6) the production process of the method does not generate three wastes, is safe and environment-friendly, saves water and reduces emission, and is beneficial to realizing automatic large-scale production.
Detailed Description
In order to further explain the meaning of the present invention, the following examples are given to explain the contents of the present invention, but the contents are not limited thereto.
Example 1
Preheating hydroxyl ethylidene diphosphonic acid liquid with the activity content of 51.34 percent to 82 ℃ by a graphite heater respectively, removing hydrogen chloride and a small amount of water vapor in a system by gas-liquid separation, and then continuously pumping the liquid into a distillation kettle at a constant speed of 250 kg/h; continuously feeding for 1 hour until the volume of the material is about one third of the volume of the kettle body, starting the distillation kettle to stir, and quickly externally steaming and concentrating under the negative pressure condition of keeping the system temperature at 125 +/-1 ℃ and minus 0.06 MPa; after 3 hours of continuous feeding, the active content of the materials in the distillation kettle is 70.28 percent, the volume of the materials in the distillation kettle reaches the set material transferring liquid level, a valve at the bottom of the distillation kettle and a material transferring pump are automatically started to continuously transfer the materials cooled to 62 ℃ into a first-stage crystallization kettle for crystallization according to 282kg/h, and the step-by-step continuous crystallization is carried out by sequentially completing step-by-step automatic material transferring between 1-4 stages of crystallization kettles connected in series end to end and controlling the stirring speed to be 120 revolutions per minute and the natural cooling gradient of 5-20 ℃/step under the control of a PLC automatic interlocking device established between a liquid level meter arranged on each stage of crystallization kettle and a kettle top feeding valve and a kettle bottom discharging valve; wherein the injection time of the solid-liquid mixed material in the 1-4-stage crystallization kettle from the lowest liquid level to the highest liquid level is 2.5 hours, 2.5 hours and 3 hours respectively; the temperature of the mixed materials after natural cooling in the 1-4-level crystallization kettle is respectively as follows: introducing circulating cooling water into the interlayer of the last-stage crystallization kettle, namely the 4 th-stage crystallization kettle, at 55 ℃, 48 ℃, 36 ℃ and 26 ℃, cooling to 20.5 ℃, slowly stirring for 2 hours to ensure that the system is fully crystallized, and centrifuging, drying and separating the mixed material to respectively obtain a white transparent regular crystal product of hydroxyethylidene diphosphonic acid and a centrifugal mother solution; the centrifugal mother liquor is circulated to a concentration kettle for continuous crystallization repeatedly, the mixed centrifugal mother liquor is recycled until the chroma is 190Hazen, the total production period is 7585kg, the chloride ion content (calculated by Cl < - >) is 0.005 percent, the product yield is 91.38 percent, the total separated mother liquor is 957.44kg, the activity content is 60.25 percent, and the total yield of the hydroxyethylidene diphosphonic acid is 98.31 percent, wherein the total content of the hydroxyethylidene diphosphonic acid white transparent crystal product is 98.71 percent. The granularity is suitable and uniform, the pipeline is not blocked, and the centrifugation is convenient.
Example 2
Preheating hydroxyl ethylidene diphosphonic acid liquid with the activity content of 60.29 percent to 90 ℃ by a graphite heater respectively, removing hydrogen chloride and a small amount of water vapor in a system by gas-liquid separation, and then continuously pumping the liquid into a distillation kettle at a constant speed according to the flow rate of 200 kg/h; continuously feeding for 1.5 hours until the volume of the material is about one third of the volume of the kettle body, starting the distillation kettle to stir, and quickly externally steaming and concentrating under the negative pressure condition of maintaining the system temperature at 130 +/-1 ℃ and-0.04 MPa; after 4 hours of continuous feeding, the active content of the materials in the distillation kettle is 70.04 percent, the volume of the materials in the distillation kettle reaches the set material transferring liquid level, a valve at the bottom of the distillation kettle and a material transferring pump are automatically started to continuously transfer the materials cooled to 65 ℃ into a first-stage crystallization kettle for crystallization according to the flow of 250kg/h, and the gradual continuous crystallization is carried out by sequentially completing the gradual automatic material transferring among 1-3 stages of crystallization kettles connected in series end to end and controlling the stirring speed to be 150 revolutions per minute and the natural cooling gradient of 5-20 ℃/stage through the control of a PLC automatic interlocking device arranged among a liquid level meter arranged on each stage of crystallization kettle, a kettle top feeding valve and a kettle bottom discharging valve; wherein the injection time of the solid-liquid mixed material in the 1-3-stage crystallization kettle from the lowest liquid level to the highest liquid level is 3 hours, 3 hours and 3.5 hours respectively; the temperature of the mixed materials after natural cooling in the 1-3-level crystallization kettle is respectively as follows: introducing circulating cooling water into the interlayer of the last stage, namely the 3 rd stage crystallization kettle at 58 ℃, 49 ℃ and 35 ℃, cooling to 20 ℃, slowly stirring for 2 hours to ensure that the system is fully crystallized, and centrifuging, drying and separating the mixed material to respectively obtain a white transparent regular crystal product of hydroxyethylidene diphosphonic acid and a centrifugal mother liquor; the centrifugal mother liquor is circulated to a concentration kettle for continuous crystallization, the mixed centrifugal mother liquor is recycled until the chroma is 180Hazen, the total content of produced hydroxyethylidene diphosphonic acid white transparent crystal products with the activity content of 98.23 percent is 5889kg, the chloride ion content (calculated by Cl < - >) is 0.003 percent, and the product yield is 90.47 percent; the total amount of the mother liquor obtained by separation was 878kg, the activity content was 60.17%, and the total yield of hydroxyethylidene diphosphonic acid was 98.41%. The granularity is suitable and uniform, the pipeline is not blocked, and the centrifugation is convenient.
Example 3
Preheating hydroxyl ethylidene diphosphonic acid liquid with the activity content of 60.57 percent to 75 ℃ by a graphite heater respectively, removing hydrogen chloride and a small amount of water vapor in a system by gas-liquid separation, and then continuously pumping the liquid into a distillation kettle at a constant speed according to the flow rate of 300 kg/h; when the material volume is continuously fed to be about one third of the volume of the kettle body, the distillation kettle is started to stir, the system temperature is maintained at 128 +/-2 ℃, the rapid external evaporation concentration is carried out under the negative pressure condition of-0.04 MPa, after the material is continuously fed for 2.8 hours, the active content of the material in the distillation kettle is 70.08 percent, the volume of the material in the distillation kettle reaches the set material transferring liquid level, a valve at the bottom of the distillation kettle and a material transferring pump are automatically started to continuously transfer the material cooled to 70 ℃ to a first-stage crystallization kettle for crystallization according to the flow rate of 320kg/h,through the control of a PLC automatic interlocking device established among a liquid level meter arranged on each stage of crystallization kettle, a kettle top feeding valve and a kettle bottom discharging valve, the gradual automatic material transfer is sequentially completed among 1-5 stages of crystallization kettles connected in series end to end, the stirring speed is controlled to be 80 revolutions per minute and the natural cooling gradient of 5-20 ℃/stage is controlled, and the gradual continuous crystallization is carried out; wherein the injection time of the solid-liquid mixed material in the 1-5-stage crystallization kettle from the lowest liquid level to the highest liquid level is 2 hours, 2 hours and 3 hours respectively; the temperature of the mixed materials after natural cooling in the 1-5-level crystallization kettle is respectively as follows: introducing circulating cooling water into the interlayer of the last-stage crystallization kettle, namely the 5 th-stage crystallization kettle, at 65 ℃, 58 ℃, 44 ℃, 32 ℃ and 24 ℃, cooling to 19 ℃, slowly stirring for 2 hours to ensure that the system is fully crystallized, and centrifuging, drying and separating the mixed material to respectively obtain a hydroxyethylidene diphosphonic acid crystal product and a centrifugal mother liquor; the centrifugal mother liquor is circulated to a concentration kettle for continuous crystallization, the mixed centrifugal mother liquor is recycled until the chroma is 185Hazen, the total content of produced white transparent regular crystals of hydroxyethylidene diphosphonic acid with the activity content of 98.03 percent is 8787kg, and the content of chloride ions (in terms of Cl) is-Calculated) 0.009%, the product yield is 90.47%; the mother liquor obtained by separation amounted to 1334kg, the activity content was 59.33%, and the total yield of hydroxyethylidene diphosphonic acid was 98.49%. The granularity is suitable and uniform, the pipeline is not blocked, and the centrifugation is convenient.
Comparative example 1 (conventional single-pot concentration crystallization method)
Pumping 2000kg of hydroxyethylidene diphosphonic acid liquid with the activity content of 60.57 percent into a reaction kettle, rapidly heating to 130 ℃ under the stirring condition, simultaneously establishing negative pressure of-0.05 MPa for rapid external evaporation and concentration until the activity content is 75.32 percent, controlling the stirring speed to be 120 r/min, adding seed crystals, introducing circulating water for cooling, cooling to 20 +/-2 ℃ according to the gradient of 5-10 ℃/h, standing and aging for 1-2 hours, centrifuging and drying to obtain 890.68kg of hydroxyethylidene diphosphonic acid crystals with the activity content of 97.41 percent, wherein the yield of the one-time crystallization is 75.48 percent, repeating the operation steps for the centrifugal mother liquor for cyclic recrystallization for three times, the total yield is 87.92 percent, and the chloride ion content (taking Cl as the Cl ion)-Calculated) was 0.011%.
Comparative example 2
The other operation conditions and process parameters are the same as those of the embodiment 2, the hydroxyethylidene diphosphonic acid liquid with the activity of 70.04 percent and the temperature of 120 ℃ after distillation concentration is directly and continuously transferred into a first-stage crystallization kettle for crystallization according to the flow of 180kg/h without cooling, and the gradual continuous crystallization is carried out by sequentially completing the gradual automatic material transfer between 1-3 stages of crystallization kettles connected in series end to end and controlling the stirring speed to be 140 r/min and the natural cooling gradient of 5-20 ℃/stage through the control of a liquid level meter arranged on each stage of crystallization kettle, a kettle top feeding valve and a kettle bottom discharging valve by an established PLC automatic interlocking device; wherein the phenomenon of crystal sudden-precipitation appears in 1~2 grades of crystallization cauldron, and 1~3 grades of mixed material temperature after the natural cooling is respectively: introducing circulating cooling water into the interlayer of the last stage, namely the 3 rd stage crystallization kettle at 103 ℃, 87 ℃ and 72 ℃, cooling to 20 ℃, slowly stirring for 2 hours to ensure that the system is fully crystallized, centrifuging and drying the mixed material to respectively obtain a hydroxyethylidene diphosphonic acid crystal product and centrifugal mother liquor, and obtaining 1007.49kg of hydroxyethylidene diphosphonic acid white crystal product with the activity content of 93.01 percent in total and the chloride ion content (in terms of Cl)-Calculated) 0.015 percent, and the one-time crystallization yield is 78.24 percent; the total amount of the mother liquor obtained by separation was 994.36kg, and the activity content was 69.83%.
Comparative example 3
The stirring speed in the grade 1-4 crystallization kettle is controlled to be 200 r/min, other operation conditions and process parameters are the same as those of the grade 1, 1-2 crystallization kettle in the example, the phenomenon of serious sudden precipitation occurs, precipitated crystal particles are small, the crystal is in a fine powder shape, the activity content of the hydroxyethylidene diphosphonic acid crystal is 95.39%, the content of chloride ions (calculated by Cl < - >) is 0.031%, and the yield of one-time crystallization is 80.24%.
Comparative example 4
The stirring speed in the 1-4-stage crystallization kettle is controlled to be 30 r/min, the phenomenon of sudden precipitation occurs in the same operation conditions and process parameters as those in the 1-2-stage crystallization kettle of the embodiment 1, and the precipitated crystals have different particle sizes and irregular shapes, so that the active content of the hydroxyethylidene diphosphonic acid crystal is 90.08 percent, and the content of chloride ions (in terms of Cl & lt- & gt) is obtained-Calculated) was 0.035%, and the one-shot crystallization yield was 81.02%.
Claims (6)
1. A continuous production method of hydroxyethylidene diphosphonic acid crystal is characterized by comprising the following steps:
(1) preheating hydroxyethylidene diphosphonic acid liquid with the activity content of 50-65%, carrying out gas-liquid separation, and then continuously pumping the liquid into a concentration kettle at a constant speed;
(2) stirring and heating are started, and simultaneously, external evaporation concentration purification is continuously carried out under negative pressure;
(3) when the active content of the materials in the concentration kettle is more than or equal to 70 percent, the high-temperature materials are cooled and then sequentially transferred step by step between 1-n stages of crystallization kettles connected in series end to end, and are continuously crystallized under the conditions of stirring and cooling; n is more than or equal to 2 and less than or equal to 8;
(4) cooling the mixed material in an nth-stage crystallization kettle, maintaining the temperature of the system at 20 +/-2 ℃ to fully crystallize the system, separating and drying the mixed material to obtain a hydroxyethylidene diphosphonic acid crystal product with the activity content of more than or equal to 98%, and collecting and recycling mother liquor obtained by separation.
2. The method according to claim 1, wherein the temperature of the preheated liquid product in the step (1) is in the range of 60-100 ℃.
3. The method according to claim 1, wherein the external concentration temperature in the step (2) is 110 to 150 ℃.
4. The method according to claim 1, wherein the temperature of the cooled material in the step (3) is 60-70 ℃.
5. The method as claimed in claim 1, wherein the temperature gradient of the 1-n stage crystallization kettle in the step (3) is in the range of 5-20 ℃/stage.
6. The method according to any one of claims 1 and 5, wherein in each stage of crystallization kettle, the temperature reduction gradient of the temperature of the crystallization kettle of 1-2 stages is 5-10 ℃/stage, and the temperature gradient range of the crystallization kettle of 3-n stages is 10-20 ℃/stage; the stirring speed of the 1-n-stage crystallization kettle is gradually reduced; the nth stage is cooled to 20 + -2 deg.C by circulation.
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| US3400147A (en) * | 1965-03-30 | 1968-09-03 | Procter & Gamble | Process for preparation of organophosphorous compounds |
| CN103435645A (en) * | 2013-09-09 | 2013-12-11 | 山东省泰和水处理有限公司 | Preparation method of low iron and low chloride hydroxyethylidene-1,1-diphosphonic acid (HEDP) |
| CN109608372A (en) * | 2018-12-24 | 2019-04-12 | 天津大学 | A kind of multistage continuous crystallisation process of corynebacterium methionine crystal |
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| US3400147A (en) * | 1965-03-30 | 1968-09-03 | Procter & Gamble | Process for preparation of organophosphorous compounds |
| CN103435645A (en) * | 2013-09-09 | 2013-12-11 | 山东省泰和水处理有限公司 | Preparation method of low iron and low chloride hydroxyethylidene-1,1-diphosphonic acid (HEDP) |
| CN109608372A (en) * | 2018-12-24 | 2019-04-12 | 天津大学 | A kind of multistage continuous crystallisation process of corynebacterium methionine crystal |
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