CN113754567B - Preparation process of novel refined guanidine carbonate - Google Patents
Preparation process of novel refined guanidine carbonate Download PDFInfo
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- CN113754567B CN113754567B CN202111190911.1A CN202111190911A CN113754567B CN 113754567 B CN113754567 B CN 113754567B CN 202111190911 A CN202111190911 A CN 202111190911A CN 113754567 B CN113754567 B CN 113754567B
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- guanidine hydrochloride
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- STIAPHVBRDNOAJ-UHFFFAOYSA-N carbamimidoylazanium;carbonate Chemical compound NC(N)=N.NC(N)=N.OC(O)=O STIAPHVBRDNOAJ-UHFFFAOYSA-N 0.000 title claims abstract description 74
- 238000002360 preparation method Methods 0.000 title claims abstract description 29
- 229960000789 guanidine hydrochloride Drugs 0.000 claims abstract description 93
- PJJJBBJSCAKJQF-UHFFFAOYSA-N guanidinium chloride Chemical compound [Cl-].NC(N)=[NH2+] PJJJBBJSCAKJQF-UHFFFAOYSA-N 0.000 claims abstract description 93
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Chemical compound O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 65
- 239000000243 solution Substances 0.000 claims abstract description 64
- FAPWRFPIFSIZLT-UHFFFAOYSA-M Sodium chloride Chemical compound [Na+].[Cl-] FAPWRFPIFSIZLT-UHFFFAOYSA-M 0.000 claims abstract description 52
- 239000012153 distilled water Substances 0.000 claims abstract description 51
- 239000012043 crude product Substances 0.000 claims abstract description 45
- 238000003756 stirring Methods 0.000 claims abstract description 42
- 238000001704 evaporation Methods 0.000 claims abstract description 36
- 230000008020 evaporation Effects 0.000 claims abstract description 36
- 238000001914 filtration Methods 0.000 claims abstract description 34
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 claims abstract description 33
- 238000002425 crystallisation Methods 0.000 claims abstract description 29
- 230000008025 crystallization Effects 0.000 claims abstract description 29
- 239000007864 aqueous solution Substances 0.000 claims abstract description 28
- 238000001816 cooling Methods 0.000 claims abstract description 26
- 239000011780 sodium chloride Substances 0.000 claims abstract description 26
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 claims abstract description 24
- 238000006243 chemical reaction Methods 0.000 claims abstract description 24
- 239000001569 carbon dioxide Substances 0.000 claims abstract description 12
- 229910002092 carbon dioxide Inorganic materials 0.000 claims abstract description 12
- 238000004090 dissolution Methods 0.000 claims abstract description 11
- 238000000034 method Methods 0.000 claims abstract description 9
- 239000007787 solid Substances 0.000 claims abstract description 7
- 239000013078 crystal Substances 0.000 claims abstract description 6
- 125000002795 guanidino group Chemical group C(N)(=N)N* 0.000 claims abstract description 6
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims description 102
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 claims description 66
- JIAARYAFYJHUJI-UHFFFAOYSA-L zinc dichloride Chemical compound [Cl-].[Cl-].[Zn+2] JIAARYAFYJHUJI-UHFFFAOYSA-L 0.000 claims description 52
- 239000002002 slurry Substances 0.000 claims description 47
- RTZKZFJDLAIYFH-UHFFFAOYSA-N Diethyl ether Chemical compound CCOCC RTZKZFJDLAIYFH-UHFFFAOYSA-N 0.000 claims description 45
- 239000006185 dispersion Substances 0.000 claims description 45
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 claims description 30
- OKKJLVBELUTLKV-UHFFFAOYSA-N Methanol Chemical compound OC OKKJLVBELUTLKV-UHFFFAOYSA-N 0.000 claims description 30
- 239000003054 catalyst Substances 0.000 claims description 30
- NLXLAEXVIDQMFP-UHFFFAOYSA-N Ammonia chloride Chemical compound [NH4+].[Cl-] NLXLAEXVIDQMFP-UHFFFAOYSA-N 0.000 claims description 28
- 229910052799 carbon Inorganic materials 0.000 claims description 27
- 239000011592 zinc chloride Substances 0.000 claims description 26
- 235000005074 zinc chloride Nutrition 0.000 claims description 26
- 238000003825 pressing Methods 0.000 claims description 21
- 238000001179 sorption measurement Methods 0.000 claims description 21
- 238000001035 drying Methods 0.000 claims description 20
- 238000005507 spraying Methods 0.000 claims description 20
- QGBSISYHAICWAH-UHFFFAOYSA-N dicyandiamide Chemical compound NC(N)=NC#N QGBSISYHAICWAH-UHFFFAOYSA-N 0.000 claims description 18
- 239000012452 mother liquor Substances 0.000 claims description 16
- QGZKDVFQNNGYKY-UHFFFAOYSA-N Ammonia Chemical compound N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 claims description 15
- 235000019270 ammonium chloride Nutrition 0.000 claims description 14
- 239000010413 mother solution Substances 0.000 claims description 11
- 239000001267 polyvinylpyrrolidone Substances 0.000 claims description 11
- 229920000036 polyvinylpyrrolidone Polymers 0.000 claims description 11
- 235000013855 polyvinylpyrrolidone Nutrition 0.000 claims description 11
- 238000004064 recycling Methods 0.000 claims description 11
- 239000001856 Ethyl cellulose Substances 0.000 claims description 10
- ZZSNKZQZMQGXPY-UHFFFAOYSA-N Ethyl cellulose Chemical compound CCOCC1OC(OC)C(OCC)C(OCC)C1OC1C(O)C(O)C(OC)C(CO)O1 ZZSNKZQZMQGXPY-UHFFFAOYSA-N 0.000 claims description 10
- 230000004913 activation Effects 0.000 claims description 10
- 239000011247 coating layer Substances 0.000 claims description 10
- 229920001249 ethyl cellulose Polymers 0.000 claims description 10
- 235000019325 ethyl cellulose Nutrition 0.000 claims description 10
- 239000000706 filtrate Substances 0.000 claims description 10
- 239000000725 suspension Substances 0.000 claims description 10
- 238000010306 acid treatment Methods 0.000 claims description 9
- 238000001556 precipitation Methods 0.000 claims description 9
- 235000013162 Cocos nucifera Nutrition 0.000 claims description 8
- 244000060011 Cocos nucifera Species 0.000 claims description 8
- 230000008569 process Effects 0.000 claims description 7
- XLOMVQKBTHCTTD-UHFFFAOYSA-N Zinc monoxide Chemical compound [Zn]=O XLOMVQKBTHCTTD-UHFFFAOYSA-N 0.000 claims description 6
- 239000002994 raw material Substances 0.000 claims description 6
- 238000005119 centrifugation Methods 0.000 claims description 5
- 238000010438 heat treatment Methods 0.000 claims description 5
- 238000002844 melting Methods 0.000 claims description 5
- 230000008018 melting Effects 0.000 claims description 5
- 238000004321 preservation Methods 0.000 claims description 5
- 238000010992 reflux Methods 0.000 claims description 5
- 230000001105 regulatory effect Effects 0.000 claims description 5
- 229920006395 saturated elastomer Polymers 0.000 claims description 5
- 238000002791 soaking Methods 0.000 claims description 5
- 238000009210 therapy by ultrasound Methods 0.000 claims description 4
- TVWXRUVDPUAFFG-UHFFFAOYSA-N zinc oxygen(2-) hydrochloride Chemical compound [O-2].[Zn+2].Cl TVWXRUVDPUAFFG-UHFFFAOYSA-N 0.000 claims description 4
- UGZADUVQMDAIAO-UHFFFAOYSA-L zinc hydroxide Chemical compound [OH-].[OH-].[Zn+2] UGZADUVQMDAIAO-UHFFFAOYSA-L 0.000 claims description 3
- 229940007718 zinc hydroxide Drugs 0.000 claims description 3
- 229910021511 zinc hydroxide Inorganic materials 0.000 claims description 3
- 239000011787 zinc oxide Substances 0.000 claims description 3
- 239000002244 precipitate Substances 0.000 claims description 2
- 239000000203 mixture Substances 0.000 claims 1
- 239000000047 product Substances 0.000 abstract description 11
- ZRALSGWEFCBTJO-UHFFFAOYSA-N anhydrous guanidine Natural products NC(N)=N ZRALSGWEFCBTJO-UHFFFAOYSA-N 0.000 abstract description 8
- CHJJGSNFBQVOTG-UHFFFAOYSA-N N-methyl-guanidine Natural products CNC(N)=N CHJJGSNFBQVOTG-UHFFFAOYSA-N 0.000 abstract description 6
- SWSQBOPZIKWTGO-UHFFFAOYSA-N dimethylaminoamidine Natural products CN(C)C(N)=N SWSQBOPZIKWTGO-UHFFFAOYSA-N 0.000 abstract description 6
- 229960004198 guanidine Drugs 0.000 abstract description 6
- 229960002668 sodium chloride Drugs 0.000 abstract description 4
- 239000012535 impurity Substances 0.000 description 9
- 229910052751 metal Inorganic materials 0.000 description 5
- 239000002184 metal Substances 0.000 description 5
- 230000000694 effects Effects 0.000 description 4
- 230000007613 environmental effect Effects 0.000 description 4
- 239000011949 solid catalyst Substances 0.000 description 4
- HCHKCACWOHOZIP-UHFFFAOYSA-N Zinc Chemical compound [Zn] HCHKCACWOHOZIP-UHFFFAOYSA-N 0.000 description 3
- 238000001514 detection method Methods 0.000 description 3
- 238000000926 separation method Methods 0.000 description 3
- 238000002604 ultrasonography Methods 0.000 description 3
- 229910052725 zinc Inorganic materials 0.000 description 3
- 239000011701 zinc Substances 0.000 description 3
- PTFCDOFLOPIGGS-UHFFFAOYSA-N Zinc dication Chemical compound [Zn+2] PTFCDOFLOPIGGS-UHFFFAOYSA-N 0.000 description 2
- 230000015572 biosynthetic process Effects 0.000 description 2
- 239000003153 chemical reaction reagent Substances 0.000 description 2
- 150000002357 guanidines Chemical class 0.000 description 2
- 229910001385 heavy metal Inorganic materials 0.000 description 2
- -1 iminourea carbonate Chemical compound 0.000 description 2
- 238000011065 in-situ storage Methods 0.000 description 2
- 239000007788 liquid Substances 0.000 description 2
- 230000020477 pH reduction Effects 0.000 description 2
- 239000002699 waste material Substances 0.000 description 2
- FYYHWMGAXLPEAU-UHFFFAOYSA-N Magnesium Chemical compound [Mg] FYYHWMGAXLPEAU-UHFFFAOYSA-N 0.000 description 1
- 238000010521 absorption reaction Methods 0.000 description 1
- 239000000654 additive Substances 0.000 description 1
- 230000000996 additive effect Effects 0.000 description 1
- 229910052783 alkali metal Inorganic materials 0.000 description 1
- 150000001340 alkali metals Chemical class 0.000 description 1
- 229920003180 amino resin Polymers 0.000 description 1
- 150000003863 ammonium salts Chemical class 0.000 description 1
- 239000003963 antioxidant agent Substances 0.000 description 1
- 230000003078 antioxidant effect Effects 0.000 description 1
- 239000011230 binding agent Substances 0.000 description 1
- 229910052793 cadmium Inorganic materials 0.000 description 1
- BDOSMKKIYDKNTQ-UHFFFAOYSA-N cadmium atom Chemical compound [Cd] BDOSMKKIYDKNTQ-UHFFFAOYSA-N 0.000 description 1
- 229910021386 carbon form Inorganic materials 0.000 description 1
- 230000003197 catalytic effect Effects 0.000 description 1
- 239000004568 cement Substances 0.000 description 1
- 230000008859 change Effects 0.000 description 1
- 239000000460 chlorine Substances 0.000 description 1
- 229910052801 chlorine Inorganic materials 0.000 description 1
- 238000005265 energy consumption Methods 0.000 description 1
- 239000011440 grout Substances 0.000 description 1
- 239000011777 magnesium Substances 0.000 description 1
- 229910052749 magnesium Inorganic materials 0.000 description 1
- WPBNNNQJVZRUHP-UHFFFAOYSA-L manganese(2+);methyl n-[[2-(methoxycarbonylcarbamothioylamino)phenyl]carbamothioyl]carbamate;n-[2-(sulfidocarbothioylamino)ethyl]carbamodithioate Chemical compound [Mn+2].[S-]C(=S)NCCNC([S-])=S.COC(=O)NC(=S)NC1=CC=CC=C1NC(=S)NC(=O)OC WPBNNNQJVZRUHP-UHFFFAOYSA-L 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 239000002923 metal particle Substances 0.000 description 1
- 238000006386 neutralization reaction Methods 0.000 description 1
- 230000002093 peripheral effect Effects 0.000 description 1
- 239000000049 pigment Substances 0.000 description 1
- 239000012716 precipitator Substances 0.000 description 1
- 239000012495 reaction gas Substances 0.000 description 1
- 230000009467 reduction Effects 0.000 description 1
- 238000007670 refining Methods 0.000 description 1
- 239000013557 residual solvent Substances 0.000 description 1
- 239000011347 resin Substances 0.000 description 1
- 229920005989 resin Polymers 0.000 description 1
- 239000000344 soap Substances 0.000 description 1
- 229910052708 sodium Inorganic materials 0.000 description 1
- 239000011734 sodium Substances 0.000 description 1
- 239000003381 stabilizer Substances 0.000 description 1
- 239000004094 surface-active agent Substances 0.000 description 1
- 238000003786 synthesis reaction Methods 0.000 description 1
- 239000000271 synthetic detergent Substances 0.000 description 1
- 229920002994 synthetic fiber Polymers 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C277/00—Preparation of guanidine or its derivatives, i.e. compounds containing the group, the singly-bound nitrogen atoms not being part of nitro or nitroso groups
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J20/00—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof
- B01J20/02—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof comprising inorganic material
- B01J20/20—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof comprising inorganic material comprising free carbon; comprising carbon obtained by carbonising processes
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J27/00—Catalysts comprising the elements or compounds of halogens, sulfur, selenium, tellurium, phosphorus or nitrogen; Catalysts comprising carbon compounds
- B01J27/06—Halogens; Compounds thereof
- B01J27/138—Halogens; Compounds thereof with alkaline earth metals, magnesium, beryllium, zinc, cadmium or mercury
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C277/00—Preparation of guanidine or its derivatives, i.e. compounds containing the group, the singly-bound nitrogen atoms not being part of nitro or nitroso groups
- C07C277/02—Preparation of guanidine or its derivatives, i.e. compounds containing the group, the singly-bound nitrogen atoms not being part of nitro or nitroso groups of guanidine from cyanamide, calcium cyanamide or dicyandiamides
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C277/00—Preparation of guanidine or its derivatives, i.e. compounds containing the group, the singly-bound nitrogen atoms not being part of nitro or nitroso groups
- C07C277/06—Purification or separation of guanidine
Landscapes
- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Analytical Chemistry (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Inorganic Chemistry (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
Abstract
The invention discloses a preparation process of novel refined guanidine carbonate, which comprises the steps of adding guanidine hydrochloride into distilled water, uniformly stirring to form an aqueous solution, adding sodium hydroxide solid at constant temperature, and stirring to obtain a mixed aqueous solution of guanidino and sodium chloride; adding the mixed aqueous solution into a concentration kettle for evaporation treatment, and naturally cooling and separating sodium chloride crystals out to obtain a first concentrated solution; slowly introducing carbon dioxide into the first concentrated solution until the pH reaches 9, and centrifuging to obtain a guanidine carbonate crude product; adding the guanidine carbonate crude product into distilled water for constant temperature dissolution, transferring to a concentration kettle for concentration and filtration to obtain a second concentrated solution; transferring the second concentrated solution into a crystallization kettle, cooling and crystallizing, and filtering to obtain high-purity guanidine carbonate. The method fully utilizes the solubility of sodium chloride, guanidine hydrochloride and guanidine radical in water in the reaction stage, greatly reduces the content of sodium chloride in a concentrated system, effectively reduces the content of sodium chloride in subsequent products, and improves the purity of guanidine carbonate.
Description
Technical Field
The invention belongs to the field of synthesis, and particularly relates to a preparation process of novel refined guanidine carbonate.
Background
Guanidine carbonate, known as guanidine carbonate, also known as iminourea carbonate, is an organic synthetic material and an analytical reagent for pH regulator, antioxidant, resin stabilizer, guanidine soap, etc. of amino resin, and can also be used as an additive for cement grout and surfactant. In the context of synthetic detergents, are used as wetters and builders. In the weight measurement of zinc, cadmium and manganese, the catalyst is used as a precipitator and also used for separating magnesium from alkali metal. At present, guanidine carbonate is generally prepared by taking dicyandiamide and ammonium salt (ammonium chloride) as raw materials, carrying out melt reaction at 170-230 ℃ to obtain a guanidine hydrochloride crude product, refining to obtain a finished product, adding sodium alkoxide for neutralization, and then enabling the free guanidine to absorb carbon dioxide. The process has extremely high energy consumption, and meanwhile, the guanidine carbonate has more impurities, so that the requirements of analytical reagents and medical intermediate production raw materials are difficult to meet.
Disclosure of Invention
Aiming at the problems in the prior art, the invention provides a novel preparation process of refined guanidine carbonate, which solves the technical difficulties of high-purity guanidine carbonate, fully utilizes the solubility of sodium chloride, guanidine hydrochloride and guanidine radical in water in the reaction stage, greatly reduces the content of sodium chloride in a concentrated system, effectively reduces the content of sodium chloride in subsequent products and improves the purity of guanidine carbonate.
In order to achieve the technical purpose, the technical scheme of the invention is as follows:
a preparation process of novel refined guanidine carbonate comprises the following steps:
step 1, adding guanidine hydrochloride into distilled water, uniformly stirring to form an aqueous solution, and then adding sodium hydroxide solid at constant temperature and stirring to obtain a mixed aqueous solution of guanidino and sodium chloride; the concentration of the guanidine hydrochloride in distilled water is 200-400g/L, the adding amount of the sodium hydroxide is 40-50% of the mass of the guanidine hydrochloride, the constant-temperature adding temperature is 40-60 ℃, and the stirring speed is 1000-2000r/min;
step 2, adding the mixed aqueous solution into a concentration kettle for evaporation treatment, and then naturally cooling and separating out sodium chloride crystals to obtain a first concentrated solution; the temperature of the evaporation treatment is 48-50 ℃, the vacuum pressure is not more than-0.085 MPa, the evaporation time is 4 hours, the water mass content of the solution after the evaporation treatment is not more than 8%, and the natural cooling temperature is 30-35 ℃;
step 3, slowly introducing carbon dioxide into the first concentrated solution until the pH reaches 9, and centrifuging to obtain a guanidine carbonate crude product, wherein the introducing speed of the carbon dioxide is 2-5mL/min; adding the mother solution after centrifugation into distilled water in the step 1 after being subjected to hydrochloric acid;
step 4, adding the guanidine carbonate crude product into distilled water for constant temperature dissolution, transferring the guanidine carbonate crude product into a concentration kettle for concentration and filtration to obtain a second concentrated solution; the mass ratio of the guanidine carbonate crude product to distilled water is 1.1-1.2:1, and the constant-temperature dissolution temperature is 65-68 ℃; the temperature of concentration and evaporation in concentration and filtration is 60-65 ℃, the vacuum pressure is not more than-0.085 MPa, the evaporation time is 5h, and the water mass content of the solution after evaporation treatment is not more than 10%; filtering in the concentration and filtration to completely remove insoluble matters to obtain a guanidine carbonate solution;
and 5, transferring the second concentrated solution into a crystallization kettle for cooling crystallization, filtering to obtain high-purity guanidine carbonate, wherein the temperature of the cooling crystallization is 30-35 ℃, and the crystallized mother solution is returned to the reaction kettle for recycling, and further, the mother solution is added into the guanidine hydrochloride solution after being regulated by hydrochloric acid.
The guanidine hydrochloride is prepared from dicyandiamide and ammonium chloride serving as raw materials to form the medical-grade guanidine hydrochloride.
Further, the preparation method of guanidine hydrochloride comprises the following steps: a1, adding dicyandiamide and ammonium chloride into a reaction kettle, adding a solid catalyst, heating to 160-170 ℃ for heat preservation and melting reaction to obtain a guanidine hydrochloride crude product; the mass ratio of dicyandiamide to ammonium chloride is 1:1.2-1.3, preferably 1.27; the catalyst adopts zinc chloride catalyst, and the addition amount is 4-9% of the dicyandiamide mass; a2, adding the guanidine hydrochloride crude product into distilled water to dissolve to form guanidine hydrochloride aqueous solution, and then introducing the guanidine hydrochloride aqueous solution into an activated carbon adsorption barrel for adsorption treatment to obtain guanidine hydrochloride filtrate; the mass ratio of the guanidine hydrochloride crude product to distilled water is 1:1, coconut shell activated carbon is adopted in the activated carbon adsorption cylinder, the operating pressure of the adsorption cylinder is 0.4-0.5MPa, and the unit area (cm) 2 ) The flow rate of (2) is 500mL/min; and a3, delivering guanidine hydrochloride filtrate into a crystallization kettle, cooling and crystallizing, filtering to obtain medical-grade guanidine hydrochloride, and refluxing the mother liquor into a guanidine hydrochloride crude product for recycling. The guanidine hydrochloride can effectively remove pigment and heavy metal particle impurities in the guanidine hydrochloride aqueous solution by utilizing the adsorption performance of the activated carbon, so that the heavy metal content is effectively reduced. Meanwhile, the adoption of the high-purity guanidine hydrochloride can effectively reduce the entry of impurities into a guanidine carbonate reaction system.
Further, the preparation method of the fixed catalyst comprises the following steps: b1, adding zinc chloride into diethyl ether to form stable solution, then adding the stable solution into polyvinylpyrrolidone, carrying out low-temperature ultrasonic treatment to form dispersion, wherein the concentration of the zinc chloride in the anhydrous diethyl ether is 100-200g/L, the stirring speed is 500-1000r/min, the adding amount of the polyvinylpyrrolidone is 10-30% of the mass of the zinc chloride, the temperature of low-temperature ultrasonic treatment is 10-15 ℃, and the ultrasonic frequency is 50-80kHz; b2, introducing ammonia gas into the dispersion until the ammonia gas is dissolved and saturated, spraying distilled water on the surface of the dispersion and standing the dispersion until precipitation is not generated any more to obtain suspension, wherein the spraying area of the spraying is 10-30cm < 2 >, the spraying amount is 0.1-0.3mL/min, and in order to ensure the complete treatment of zinc chloride, the ammonia gas is repeatedly introduced and distilled water is sprayed until no precipitation is generated; in the step, a micro-solution system of distilled water and diethyl ether ensures that the distilled water enters the diethyl ether to promote the formation of double precipitation reaction; distilled water has higher density than diethyl ether, and can sink to the bottom of diethyl ether when excessive, so that the distilled water is permeated and consumed; b3, stirring and distilling the suspension to form slurry, and pressing to form a prefabricated fixed block, wherein the temperature of stirring and distilling is 60-70 ℃, the pressing pressure is 0.4-0.7MPa, and the temperature is 40-50 ℃; in the process, ammonium chloride as a product can be decomposed and removed, diethyl ether is directly converted into steam for removal, and residual solvent is removed in the pressing process, so that a zinc hydroxide solid block taking polyvinylpyrrolidone as a binder is formed; b4, soaking the prefabricated fixed block into methanol for 1-2h, and then drying at constant temperature to obtain a porous block, wherein the mass of the methanol is 5-10 times that of the prefabricated fixed block, and the constant temperature drying temperature is 150-180 ℃, so that zinc hydroxide is sintered and converted into zinc oxide; b5, placing the porous block into an activation kettle for hydrochloric acid treatment to obtain a zinc oxide chloride catalyst, wherein the hydrochloric acid treatment adopts steam hydrochloric acid, the volume ratio of hydrochloric acid steam in the activation kettle is 5-10%, and the temperature is 50-70 ℃; hydrochloric acid vapor is used as reaction gas, partial zinc oxide is converted into zinc chloride in an in-situ reaction mode, and zinc ions connected with chlorine radicals are connected with peripheral zinc ions to be cured in-situ. The use of the fixed catalyst can be quickly separated from the solution by utilizing modes such as filtration, so that not only can a good catalytic effect be achieved, but also the quick separation of the catalyst is ensured, and the existence of zinc impurities is reduced.
The preparation method of the activated carbon comprises the following steps: c1, adding active carbon into an ethanol solution, adding ethyl cellulose, and uniformly stirring to obtain dispersed slurry, wherein the concentration of the active carbon in ethanol is 100-200g/L, and the addition amount of the ethyl cellulose is 40-50% of the mass of the active carbon; c2, adding the dispersion slurry into a die, standing at a constant temperature, and forming a first fixed block with the thickness of 4-6mm in the die, wherein the temperature of standing at the constant temperature is 80-90 ℃ and the pressure is 0.2-0.4MPa; adding activated carbon into the rest of the dispersion slurry, uniformly stirring to form second dispersion slurry, and then forming a coating layer with the thickness of 1-3mm on the upper surface of the first fixed block in a mode of c 2; the mass of the active carbon in the second dispersed slurry is improved by 3-5% compared with the mass of the dispersed slurry; and c4, continuously adjusting the mass ratio of the active carbon of the dispersion slurry according to the mode of c3, adding a coating layer to obtain a prefabricated fixed block, lifting 3-5% of the mass ratio of the active carbon in the dispersion slurry each time until the mass ratio of the active carbon in the dispersion slurry is 75-80%, c5, pressing the prefabricated fixed block for 1-5h, then placing the prefabricated fixed block into ethanol for microwave treatment for 20-40min, taking out, and drying at constant temperature to obtain the active carbon, wherein the pressing temperature is 80-100 ℃, the pressure is 0.8-1.0MPa, the microwave treatment temperature is 40-50 ℃, the microwave power is 100-200W, and the constant temperature drying temperature is 100-120 ℃. The active carbon forms a gradient change structure, the aperture is primarily reduced from large to small, and good filtration is achieved, in the actual treatment process, the solution is continuously divided and refined through the continuous reduction of the aperture, and the contact surface between impurities and the active carbon is increased, so that good absorption effect is achieved, and the purity of guanidine hydrochloride is greatly improved.
From the above description, it can be seen that the present invention has the following advantages:
1. the invention solves the technical difficulty of high-purity guanidine carbonate, fully utilizes the solubility of sodium chloride, guanidine hydrochloride and guanidine radical in water in the reaction stage, greatly reduces the content of sodium chloride in a concentration system, effectively reduces the content of sodium chloride in subsequent products and improves the purity of guanidine carbonate.
2. The invention utilizes the centrifugal mother liquor and crystallization mother liquor of the guanidine carbonate crude product to recycle into the guanidine hydrochloride solution, and utilizes hydrochloric acid to carry out acidification treatment, thereby effectively converting guanidine carbonate into guanidine hydrochloride again to form a uniform guanidine salt system, reducing the influence of guanidine carbonate on the reaction system, and simultaneously preventing the guanidine carbonate from being separated out in the concentration process to cause product loss.
3. The invention solves the problem that sodium chloride and guanidine carbonate in mother liquor are difficult to separate and recycle by utilizing the recycling of centrifugal mother liquor and crystallization mother liquor, reduces the waste liquid generation of the whole system, meets the environmental protection requirement, and reduces the subsequent environmental protection treatment requirement.
4. The invention utilizes high-purity guanidine hydrochloride, effectively reduces the intake of impurities in raw materials, provides guarantee for subsequent high-purity guanidine carbonate, and simultaneously reduces the intake of metal impurities in the guanidine hydrochloride preparation process of a fixed bed reaction system, and improves the separation effect of the catalyst and the recycling of the catalyst.
Detailed Description
The invention is described in detail with reference to examples, but without any limitation to the claims of the invention.
Example 1
A novel preparation process of refined guanidine carbonate,
1. preparation of the fixed catalyst: comprising the following steps: b1, adding zinc chloride into diethyl ether to form stable solution, and then adding the stable solution into polyvinylpyrrolidone, wherein the concentration of the zinc chloride in the anhydrous diethyl ether is 100g/L, the stirring speed is 500r/min, the adding amount of the polyvinylpyrrolidone is 10% of the mass of the zinc chloride, the temperature of low-temperature ultrasound is 10 ℃, and the ultrasonic frequency is 50kHz; b2, introducing ammonia gas into the dispersion until the ammonia gas is dissolved and saturated, spraying distilled water on the surface of the dispersion, and standing the dispersion until precipitation is not generated any more to obtain a suspension, wherein the spraying area of the spraying is 10cm 2 The spraying amount is 0.1mL/min, and in order to ensure the complete treatment of zinc chloride, ammonia gas is repeatedly introduced and distilled water is sprayed until no precipitate exists; b3, stirring and distilling the suspension to form slurry, and pressing to form a prefabricated fixed block, wherein the temperature of stirring and distilling is 60 ℃, the pressing pressure is 0.4MPa, and the temperature is 40 ℃; b4, soaking the prefabricated fixed block into methanol for 1h, and then drying at constant temperature to obtain a porous block, wherein the mass of the methanol is 5 times that of the prefabricated fixed block, and the temperature of constant temperature drying is 150 ℃; b5, placing the porous block into an activation kettle for hydrochloric acid treatment to obtain chloridized oxidationAnd the zinc catalyst is prepared by adopting steam hydrochloric acid for hydrochloric acid, wherein the volume ratio of hydrochloric acid steam in the activation kettle is 5%, and the temperature is 50 ℃.
2. Preparation of coconut shell activated carbon: comprising the following steps: c1, adding coconut shell activated carbon into an ethanol solution, adding ethyl cellulose, and uniformly stirring to obtain a dispersion slurry, wherein the concentration of the activated carbon in ethanol is 100g/L, and the addition amount of the ethyl cellulose is 40% of the mass of the activated carbon; c2, adding the dispersion slurry into a die, and standing at a constant temperature, wherein the temperature of the constant temperature standing is 80 ℃ and the pressure is 0.2MPa, and a first fixed block with the thickness of 4mm is formed in the die; adding activated carbon into the rest of the dispersion slurry, uniformly stirring to form second dispersion slurry, and then forming a coating layer with the thickness of 1mm on the upper surface of the first fixed block in a mode of c 2; the mass of the active carbon in the second dispersed slurry is improved by 3% compared with the mass of the dispersed slurry; and c4, continuously adjusting the mass ratio of the activated carbon of the dispersion slurry according to the mode of c3, adding a coating layer to obtain a prefabricated fixed block, lifting 3% of the adjustment ratio each time until the mass ratio of the activated carbon in the dispersion slurry is 75%, c5, pressing the prefabricated fixed block for 1h, then placing the prefabricated fixed block into ethanol for microwave treatment for 20min, taking out, and drying at constant temperature to obtain the activated carbon, wherein the pressing temperature is 80 ℃, the pressure is 0.8MPa, the microwave treatment temperature is 40 ℃, the microwave power is 100W, and the constant-temperature drying temperature is 100 ℃.
3. Preparation of pharmaceutical grade guanidine hydrochloride: comprising the following steps: a1, adding dicyandiamide and ammonium chloride into a reaction kettle, adding a solid catalyst, heating to 160 ℃ for heat preservation and melting reaction to obtain a guanidine hydrochloride crude product; the mass ratio of dicyandiamide to ammonium chloride is 1:1.2; the catalyst adopts zinc chloride catalyst, and the addition amount of the catalyst is 4% of the mass of dicyandiamide; a2, adding the guanidine hydrochloride crude product into distilled water to dissolve to form guanidine hydrochloride aqueous solution, and then introducing the guanidine hydrochloride aqueous solution into an activated carbon adsorption barrel for adsorption treatment to obtain guanidine hydrochloride filtrate; the mass ratio of the guanidine hydrochloride crude product to distilled water is 1:1, coconut shell activated carbon is adopted in the activated carbon adsorption cylinder, the operating pressure of the adsorption cylinder is 0.4MPa, and the unit area (cm) 2 ) The flow rate of (2) is 500mL/min; a3, sending guanidine hydrochloride filtrate into a crystallization kettle for coolingAnd crystallizing, filtering to obtain medical-grade guanidine hydrochloride, and refluxing the mother liquor into the guanidine hydrochloride crude product for recycling. The detection shows that the content of the metal element in the guanidine hydrochloride is 9.6ppm, and the product is pure white.
4. Preparation of high-purity guanidine carbonate: comprising the following steps: step 1, adding guanidine hydrochloride into distilled water, uniformly stirring to form an aqueous solution, and then adding sodium hydroxide solid at constant temperature and stirring to obtain a mixed aqueous solution of guanidino and sodium chloride; the concentration of the guanidine hydrochloride in distilled water is 200g/L, the adding amount of the sodium hydroxide is 40% of the mass of the guanidine hydrochloride, the constant-temperature adding temperature is 40 ℃, and the stirring speed is 1000r/min; step 2, adding the mixed aqueous solution into a concentration kettle for evaporation treatment, and then naturally cooling and separating out sodium chloride crystals to obtain a first concentrated solution; the temperature of the evaporation treatment is 48 ℃, the vacuum pressure is not more than-0.085 MPa, the evaporation time is 4 hours, the water mass content of the solution after the evaporation treatment is 8%, and the natural cooling temperature is 30 ℃; step 3, slowly introducing carbon dioxide into the first concentrated solution until the pH reaches 9, and centrifuging to obtain a guanidine carbonate crude product, wherein the introducing speed of the carbon dioxide is 2mL/min; adding the mother solution after centrifugation into distilled water in the step 1 after being subjected to hydrochloric acid; step 4, adding the guanidine carbonate crude product into distilled water for constant temperature dissolution, transferring the guanidine carbonate crude product into a concentration kettle for concentration and filtration to obtain a second concentrated solution; the mass ratio of the guanidine carbonate crude product to distilled water is 1.1:1, and the constant-temperature dissolution temperature is 65 ℃; the concentration and evaporation temperature in concentration and filtration is 60 ℃, the vacuum pressure is not more than-0.085 MPa, the evaporation time is 5h, and the water mass content of the solution after evaporation treatment is 10%; filtering in the concentration and filtration to completely remove insoluble matters to obtain a guanidine carbonate solution; and 5, transferring the second concentrated solution into a crystallization kettle for cooling crystallization, filtering to obtain high-purity guanidine carbonate, wherein the temperature of the cooling crystallization is 30 ℃, and adding the crystallized mother solution into a guanidine hydrochloride solution after the crystallization is regulated by hydrochloric acid.
The content of the high-purity guanidine carbonate prepared in this example was 99.6%.
Example 2
A novel preparation process of refined guanidine carbonate,
1. preparation of the fixed catalyst: comprising the following steps: b1, adding zinc chloride into diethyl ether to form stable solution, and then adding the stable solution into polyvinylpyrrolidone, wherein the concentration of the zinc chloride in the anhydrous diethyl ether is 200g/L, the stirring speed is 1000r/min, the adding amount of the polyvinylpyrrolidone is 30% of the mass of the zinc chloride, the temperature of low-temperature ultrasound is 15 ℃, and the ultrasonic frequency is 80kHz; b2, introducing ammonia gas into the dispersion until the ammonia gas is dissolved and saturated, spraying distilled water on the surface of the dispersion and standing the dispersion until precipitation is not generated any more to obtain suspension, wherein the spraying area of the spraying is 30cm < 2 >, the spraying amount is 0.3mL/min, and in order to ensure the complete treatment of zinc chloride, the ammonia gas is repeatedly introduced and distilled water is sprayed until no precipitation is generated; b3, stirring and distilling the suspension to form slurry, and pressing to form a prefabricated fixed block, wherein the temperature of stirring and distilling is 70 ℃, the pressing pressure is 0.7MPa, and the temperature is 50 ℃; b4, soaking the prefabricated fixed block into methanol for 2 hours, and then drying at a constant temperature to obtain a porous block, wherein the mass of the methanol is 10 times that of the prefabricated fixed block, and the temperature of constant temperature drying is 180 ℃; b5, placing the porous block into an activation kettle for hydrochloric acid treatment to obtain a zinc oxide chloride catalyst, wherein the hydrochloric acid treatment adopts steam hydrochloric acid, the volume ratio of hydrochloric acid steam in the activation kettle is 10%, and the temperature is 70 ℃;
2. preparation of activated carbon: comprising the following steps: c1, adding active carbon into an ethanol solution, adding ethyl cellulose, and uniformly stirring to obtain dispersed slurry, wherein the concentration of the active carbon in ethanol is 200g/L, and the adding amount of the ethyl cellulose is 50% of the mass of the active carbon; c2, adding the dispersion slurry into a die, and standing at a constant temperature, wherein the temperature of the constant temperature standing is 90 ℃ and the pressure is 0.4MPa, and a first fixed block with the thickness of 6mm is formed in the die; adding activated carbon into the rest of the dispersion slurry, uniformly stirring to form second dispersion slurry, and then forming a coating layer with the thickness of 1mm on the upper surface of the first fixed block in a mode of c 2; the mass of the active carbon in the second dispersed slurry is improved by 5% compared with the mass of the dispersed slurry; and c4, continuously adjusting the mass ratio of the activated carbon of the dispersion slurry according to the mode of c3, adding a coating layer to obtain a prefabricated fixed block, lifting 3% of the adjustment ratio each time until the mass ratio of the activated carbon in the dispersion slurry is 80%, c5, pressing the prefabricated fixed block for 5 hours, then placing the prefabricated fixed block into ethanol for microwave treatment for 40min, taking out, and drying at constant temperature to obtain the activated carbon, wherein the pressing temperature is 100 ℃, the pressure is 1.0MPa, the microwave treatment temperature is 50 ℃, the microwave power is 200W, and the constant temperature drying temperature is 120 ℃.
3. Preparation of pharmaceutical grade guanidine hydrochloride: comprising the following steps: a1, adding dicyandiamide and ammonium chloride into a reaction kettle, adding a solid catalyst, heating to 170 ℃ for heat preservation and melting reaction to obtain a guanidine hydrochloride crude product; the mass ratio of dicyandiamide to ammonium chloride is 1:1.3; the catalyst adopts zinc chloride catalyst, and the addition amount is 4-9% of the dicyandiamide mass; a2, adding the guanidine hydrochloride crude product into distilled water to dissolve to form guanidine hydrochloride aqueous solution, and then introducing the guanidine hydrochloride aqueous solution into an activated carbon adsorption barrel for adsorption treatment to obtain guanidine hydrochloride filtrate; the mass ratio of the guanidine hydrochloride crude product to distilled water is 1:1, coconut shell activated carbon is adopted in the activated carbon adsorption cylinder, the operating pressure of the adsorption cylinder is 0.5MPa, and the unit area (cm) 2 ) The flow rate of (2) is 500mL/min; and a3, delivering guanidine hydrochloride filtrate into a crystallization kettle, cooling and crystallizing, filtering to obtain medical-grade guanidine hydrochloride, and refluxing the mother liquor into a guanidine hydrochloride crude product for recycling. The detection shows that the content of the metal element in the guanidine hydrochloride is 9.5ppm, and the product is pure white.
4. Preparation of high-purity guanidine carbonate: comprising the following steps: step 1, adding guanidine hydrochloride into distilled water, uniformly stirring to form an aqueous solution, and then adding sodium hydroxide solid at constant temperature and stirring to obtain a mixed aqueous solution of guanidino and sodium chloride; the concentration of the guanidine hydrochloride in distilled water is 400g/L, the adding amount of the sodium hydroxide is 50% of the mass of the guanidine hydrochloride, the constant-temperature adding temperature is 60 ℃, and the stirring speed is 2000r/min; step 2, adding the mixed aqueous solution into a concentration kettle for evaporation treatment, and then naturally cooling and separating out sodium chloride crystals to obtain a first concentrated solution; the temperature of the evaporation treatment is 50 ℃, the vacuum pressure is not more than-0.085 MPa, the evaporation time is 4 hours, the water mass content of the solution after the evaporation treatment is 8%, and the natural cooling temperature is 35 ℃; step 3, slowly introducing carbon dioxide into the first concentrated solution until the pH reaches 9, and centrifuging to obtain a guanidine carbonate crude product, wherein the introducing speed of the carbon dioxide is 5mL/min; adding the mother solution after centrifugation into distilled water in the step 1 after being subjected to hydrochloric acid; step 4, adding the guanidine carbonate crude product into distilled water for constant temperature dissolution, transferring the guanidine carbonate crude product into a concentration kettle for concentration and filtration to obtain a second concentrated solution; the mass ratio of the guanidine carbonate crude product to distilled water is 1.2:1, and the constant-temperature dissolution temperature is 68 ℃; the concentration and evaporation temperature in concentration and filtration is 65 ℃, the vacuum pressure is not more than-0.085 MPa, the evaporation time is 5h, and the water mass content of the solution after evaporation treatment is 10%; filtering in the concentration and filtration to completely remove insoluble matters to obtain a guanidine carbonate solution; and 5, transferring the second concentrated solution into a crystallization kettle for cooling crystallization, filtering to obtain high-purity guanidine carbonate, wherein the temperature of the cooling crystallization is 35 ℃, and adding the crystallized mother solution into a guanidine hydrochloride solution after the crystallization is regulated by hydrochloric acid.
The content of the high-purity guanidine carbonate prepared in this example was 99.7%.
Example 3
A novel preparation process of refined guanidine carbonate,
1. preparation of the fixed catalyst: comprising the following steps: b1, adding zinc chloride into diethyl ether to form stable solution, and then adding the stable solution into polyvinylpyrrolidone, wherein the concentration of the zinc chloride in the anhydrous diethyl ether is 150g/L, the stirring speed is 800r/min, the adding amount of the polyvinylpyrrolidone is 20% of the mass of the zinc chloride, the temperature of low-temperature ultrasound is 15 ℃, and the ultrasonic frequency is 70kHz; b2, introducing ammonia gas into the dispersion until the ammonia gas is dissolved and saturated, spraying distilled water on the surface of the dispersion and standing the dispersion until precipitation is not generated any more to obtain suspension, wherein the spraying area of the spraying is 20cm < 2 >, the spraying amount is 0.2mL/min, and in order to ensure the complete treatment of zinc chloride, the ammonia gas is repeatedly introduced and distilled water is sprayed until no precipitation is generated; b3, stirring and distilling the suspension to form slurry, and pressing to form a prefabricated fixed block, wherein the temperature of stirring and distilling is 65 ℃, the pressing pressure is 0.5MPa, and the temperature is 45 ℃; b4, soaking the prefabricated fixed block into methanol for 2 hours, and then drying at a constant temperature to obtain a porous block, wherein the mass of the methanol is 8 times that of the prefabricated fixed block, and the temperature of constant temperature drying is 170 ℃; b5, placing the porous block into an activation kettle for hydrochloric acid treatment to obtain a zinc oxide chloride catalyst, wherein the hydrochloric acid treatment adopts steam hydrochloric acid, the volume ratio of hydrochloric acid steam in the activation kettle is 8%, and the temperature is 60 ℃;
2. preparation of activated carbon: comprising the following steps: c1, adding active carbon into an ethanol solution, adding ethyl cellulose, and uniformly stirring to obtain dispersed slurry, wherein the concentration of the active carbon in ethanol is 150g/L, and the addition amount of the ethyl cellulose is 45% of the mass of the active carbon; c2, adding the dispersion slurry into a die, and standing at a constant temperature, wherein the temperature of the constant temperature standing is 85 ℃ and the pressure is 0.3MPa, and a first fixed block with the thickness of 5mm is formed in the die; adding activated carbon into the rest of the dispersion slurry, uniformly stirring to form second dispersion slurry, and then forming a 2mm coating layer on the upper surface of the first fixed block in a mode of c 2; the mass of the active carbon in the second dispersed slurry is improved by 4% compared with the mass of the dispersed slurry; and c4, continuously adjusting the mass ratio of the activated carbon of the dispersion slurry according to the mode of c3, adding a coating layer to obtain a prefabricated fixed block, lifting 3% of the adjustment ratio each time until the mass ratio of the activated carbon in the dispersion slurry is 80%, c5, pressing the prefabricated fixed block for 3 hours, then placing the prefabricated fixed block into ethanol for microwave treatment for 30min, taking out, and drying at constant temperature to obtain the activated carbon, wherein the pressing temperature is 90 ℃, the pressure is 0.9MPa, the microwave treatment temperature is 45 ℃, the microwave power is 150W, and the constant-temperature drying temperature is 110 ℃.
3. Preparation of pharmaceutical grade guanidine hydrochloride: comprising the following steps: a1, adding dicyandiamide and ammonium chloride into a reaction kettle, adding a solid catalyst, heating to 165 ℃ for heat preservation and melting reaction to obtain a guanidine hydrochloride crude product; the mass ratio of dicyandiamide to ammonium chloride is 1:1.27; the catalyst adopts zinc chloride catalyst, and the addition amount of the catalyst is 5% of the mass of dicyandiamide; a2, adding the guanidine hydrochloride crude product into distilled water to dissolve to form guanidine hydrochloride aqueous solution, and then introducing the guanidine hydrochloride aqueous solution into an activated carbon adsorption barrel for adsorption treatment to obtain guanidine hydrochloride filtrate; the mass ratio of the guanidine hydrochloride crude product to distilled water is 1:1, coconut shell activated carbon is adopted in the activated carbon adsorption cylinder, the operating pressure of the adsorption cylinder is 0.4MPa, and the unit area (c)m 2 ) The flow rate of (2) is 500mL/min; and a3, delivering guanidine hydrochloride filtrate into a crystallization kettle, cooling and crystallizing, filtering to obtain medical-grade guanidine hydrochloride, and refluxing the mother liquor into a guanidine hydrochloride crude product for recycling. The detection shows that the content of the metal element in the guanidine hydrochloride is 9.5ppm, and the product is pure white.
4. Preparation of high-purity guanidine carbonate: comprising the following steps: step 1, adding guanidine hydrochloride into distilled water, uniformly stirring to form an aqueous solution, and then adding sodium hydroxide solid at constant temperature and stirring to obtain a mixed aqueous solution of guanidino and sodium chloride; the concentration of the guanidine hydrochloride in distilled water is 300g/L, the adding amount of the sodium hydroxide is 45% of the mass of the guanidine hydrochloride, the constant-temperature adding temperature is 50 ℃, and the stirring speed is 1500r/min; step 2, adding the mixed aqueous solution into a concentration kettle for evaporation treatment, and then naturally cooling and separating out sodium chloride crystals to obtain a first concentrated solution; the temperature of the evaporation treatment is 48 ℃, the vacuum pressure is not more than-0.085 MPa, the evaporation time is 4 hours, the water mass content of the solution after the evaporation treatment is 8%, and the natural cooling temperature is 30 ℃; step 3, slowly introducing carbon dioxide into the first concentrated solution until the pH reaches 9, and centrifuging to obtain a guanidine carbonate crude product, wherein the introducing speed of the carbon dioxide is 4mL/min; adding the mother solution after centrifugation into distilled water in the step 1 after being subjected to hydrochloric acid; step 4, adding the guanidine carbonate crude product into distilled water for constant temperature dissolution, transferring the guanidine carbonate crude product into a concentration kettle for concentration and filtration to obtain a second concentrated solution; the mass ratio of the guanidine carbonate crude product to distilled water is 1.1:1, and the constant-temperature dissolution temperature is 68 ℃; the concentration and evaporation temperature in concentration and filtration is 65 ℃, the vacuum pressure is not more than-0.085 MPa, the evaporation time is 5h, and the water mass content of the solution after evaporation treatment is 10%; filtering in the concentration and filtration to completely remove insoluble matters to obtain a guanidine carbonate solution; and 5, transferring the second concentrated solution into a crystallization kettle for cooling crystallization, filtering to obtain high-purity guanidine carbonate, wherein the temperature of the cooling crystallization is 33 ℃, and adding the crystallized mother solution into a guanidine hydrochloride solution after the crystallization is regulated by hydrochloric acid.
The content of the high-purity guanidine carbonate prepared in this example was 99.7%.
In summary, the invention has the following advantages:
1. the invention solves the technical difficulty of high-purity guanidine carbonate, fully utilizes the solubility of sodium chloride, guanidine hydrochloride and guanidine radical in water in the reaction stage, greatly reduces the content of sodium chloride in a concentration system, effectively reduces the content of sodium chloride in subsequent products and improves the purity of guanidine carbonate.
2. The invention utilizes the centrifugal mother liquor and crystallization mother liquor of the guanidine carbonate crude product to recycle into the guanidine hydrochloride solution, and utilizes hydrochloric acid to carry out acidification treatment, thereby effectively converting guanidine carbonate into guanidine hydrochloride again to form a uniform guanidine salt system, reducing the influence of guanidine carbonate on the reaction system, and simultaneously preventing the guanidine carbonate from being separated out in the concentration process to cause product loss.
3. The invention solves the problem that sodium chloride and guanidine carbonate in mother liquor are difficult to separate and recycle by utilizing the recycling of centrifugal mother liquor and crystallization mother liquor, reduces the waste liquid generation of the whole system, meets the environmental protection requirement, and reduces the subsequent environmental protection treatment requirement.
4. The invention utilizes high-purity guanidine hydrochloride, effectively reduces the intake of impurities in raw materials, provides guarantee for subsequent high-purity guanidine carbonate, and simultaneously reduces the intake of metal impurities in the guanidine hydrochloride preparation process of a fixed bed reaction system, and improves the separation effect of the catalyst and the recycling of the catalyst.
It is to be understood that the foregoing detailed description of the invention is merely illustrative of the invention and is not limited to the embodiments of the invention. It will be understood by those of ordinary skill in the art that the present invention may be modified or substituted for elements thereof to achieve the same technical effects; as long as the use requirement is met, the invention is within the protection scope of the invention.
Claims (2)
1. A preparation process of refined guanidine carbonate is characterized in that: the method comprises the following steps:
step 1, adding guanidine hydrochloride into distilled water, uniformly stirring to form an aqueous solution, and then adding sodium hydroxide solid at constant temperature and stirring to obtain a mixed aqueous solution of guanidino and sodium chloride; the concentration of the guanidine hydrochloride in distilled water is 200-400g/L, the adding amount of the sodium hydroxide is 40-50% of the mass of the guanidine hydrochloride, the constant-temperature adding temperature is 40-60 ℃, and the stirring speed is 1000-2000r/min;
step 2, adding the mixed aqueous solution into a concentration kettle for evaporation treatment, and then naturally cooling and separating out sodium chloride crystals to obtain a first concentrated solution; the temperature of the evaporation treatment is 48-50 ℃, the vacuum pressure is not more than-0.085 MPa, the evaporation time is 4 hours, the water mass content of the solution after the evaporation treatment is not more than 8%, and the natural cooling temperature is 30-35 ℃;
step 3, slowly introducing carbon dioxide into the first concentrated solution until the pH reaches 9, and centrifuging to obtain a guanidine carbonate crude product; the carbon dioxide is introduced at a speed of 2-5mL/min; adding the mother solution after centrifugation into distilled water in the step 1 after being subjected to hydrochloric acid;
step 4, adding the guanidine carbonate crude product into distilled water for constant temperature dissolution, transferring the guanidine carbonate crude product into a concentration kettle for concentration and filtration to obtain a second concentrated solution; the mass ratio of the guanidine carbonate crude product to distilled water is 1.1-1.2:1, and the constant-temperature dissolution temperature is 65-68 ℃; the concentration and evaporation temperature in the concentration and filtration is 60-65 ℃, the vacuum pressure is not more than-0.085 MPa, the evaporation time is 5 hours, and the water mass content in the solution after the evaporation treatment is not more than 10%; filtering in the concentration and filtration to completely remove insoluble matters to obtain a guanidine carbonate solution;
step 5, transferring the second concentrated solution into a crystallization kettle, cooling and crystallizing, and filtering to obtain high-purity guanidine carbonate; the temperature of the cooling crystallization is 30-35 ℃, and the mother liquor after crystallization returns to the reaction kettle for recycling;
the guanidine hydrochloride in the step 1 is prepared from dicyandiamide and ammonium chloride serving as raw materials to form medical-grade guanidine hydrochloride, and the specific steps are as follows:
a1, adding dicyandiamide and ammonium chloride into a reaction kettle, adding a fixed catalyst, heating to 160-170 ℃ for heat preservation and melting reaction to obtain a guanidine hydrochloride crude product; the mass ratio of dicyandiamide to ammonium chloride is 1.27; the catalyst adopts zinc chloride catalyst, and the addition amount is 4-9% of the dicyandiamide mass; a2, adding the guanidine hydrochloride crude product into distilled water to dissolve to form guanidine hydrochloride aqueous solution, and thenIntroducing the mixture into an active carbon adsorption barrel for adsorption treatment to obtain guanidine hydrochloride filtrate; the mass ratio of the guanidine hydrochloride crude product to distilled water is 1:1, coconut shell activated carbon is adopted in the activated carbon adsorption cylinder, the operating pressure of the adsorption cylinder is 0.4-0.5MPa, and the unit surface cm is set 2 The flow rate of (2) is 500mL/min; a3, delivering guanidine hydrochloride filtrate into a crystallization kettle, cooling and crystallizing, filtering to obtain medical-grade guanidine hydrochloride, and refluxing the mother liquor into a guanidine hydrochloride crude product for recycling;
the preparation method of the fixed catalyst comprises the following steps: b1, adding zinc chloride into diethyl ether to form stable solution, then adding the stable solution into polyvinylpyrrolidone, carrying out low-temperature ultrasonic treatment to form dispersion, wherein the concentration of the zinc chloride in the anhydrous diethyl ether is 100-200g/L, the stirring speed is 500-1000r/min, the adding amount of the polyvinylpyrrolidone is 10-30% of the mass of the zinc chloride, the temperature of low-temperature ultrasonic treatment is 10-15 ℃, and the ultrasonic frequency is 50-80kHz; b2, introducing ammonia gas into the dispersion until the ammonia gas is dissolved and saturated, spraying distilled water on the surface of the dispersion, and standing the dispersion until precipitation is not generated any more to obtain a suspension, wherein the spraying area of the spraying is 10-30cm 2 The spraying amount is 0.1-0.3mL/min, and in order to ensure the complete treatment of zinc chloride, ammonia gas is repeatedly introduced and distilled water is sprayed until no precipitate exists; b3, stirring and distilling the suspension to form slurry, and pressing to form a prefabricated fixed block, wherein the temperature of stirring and distilling is 60-70 ℃, the pressing pressure is 0.4-0.7MPa, and the temperature is 40-50 ℃; b4, soaking the prefabricated fixed block into methanol for 1-2h, and then drying at constant temperature to obtain a porous block, wherein the mass of the methanol is 5-10 times that of the prefabricated fixed block, and the constant temperature drying temperature is 150-180 ℃, so that zinc hydroxide is sintered and converted into zinc oxide; b5, placing the porous block into an activation kettle for hydrochloric acid treatment to obtain a zinc oxide chloride catalyst, wherein the hydrochloric acid treatment adopts steam hydrochloric acid, the volume ratio of hydrochloric acid steam in the activation kettle is 5-10%, and the temperature is 50-70 ℃;
the preparation method of the coconut shell activated carbon comprises the following steps: c1, adding active carbon into an ethanol solution, adding ethyl cellulose, and uniformly stirring to obtain dispersed slurry, wherein the concentration of the active carbon in ethanol is 100-200g/L, and the addition amount of the ethyl cellulose is 40-50% of the mass of the active carbon; c2, adding the dispersion slurry into a die, standing at a constant temperature, and forming a first fixed block with the thickness of 4-6mm in the die, wherein the temperature of standing at the constant temperature is 80-90 ℃ and the pressure is 0.2-0.4MPa; adding activated carbon into the rest of the dispersion slurry, uniformly stirring to form second dispersion slurry, and then forming a coating layer with the thickness of 1-3mm on the upper surface of the first fixed block in a mode of c 2; the mass of the active carbon in the second dispersed slurry is improved by 3-5% compared with the mass of the dispersed slurry; and c4, continuously adjusting the mass ratio of the active carbon of the dispersion slurry according to the mode of c3, adding a coating layer to obtain a prefabricated fixed block, lifting 3-5% of the mass ratio of the active carbon in the dispersion slurry each time until the mass ratio of the active carbon in the dispersion slurry is 75-80%, c5, pressing the prefabricated fixed block for 1-5h, then placing the prefabricated fixed block into ethanol for microwave treatment for 20-40min, taking out, and drying at constant temperature to obtain the active carbon, wherein the pressing temperature is 80-100 ℃, the pressure is 0.8-1.0MPa, the microwave treatment temperature is 40-50 ℃, the microwave power is 100-200W, and the constant temperature drying temperature is 100-120 ℃.
2. The process for producing purified guanidine carbonate according to claim 1, wherein: the mother solution after crystallization is added into the guanidine hydrochloride solution after being regulated by hydrochloric acid.
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| CN1385418A (en) * | 2002-06-14 | 2002-12-18 | 方建文 | Process for preparing guanidine carbonate |
| CN1385419A (en) * | 2002-06-14 | 2002-12-18 | 方建文 | Process for preparing guanidine hydrochloride |
| CN111302977A (en) * | 2020-03-18 | 2020-06-19 | 湖南吴赣药业有限公司 | Purification method of pharmaceutical grade guanidine hydrochloride |
| CN112707848A (en) * | 2019-10-25 | 2021-04-27 | 方建文 | Preparation method of guanidine hydrochloride |
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| CN1385418A (en) * | 2002-06-14 | 2002-12-18 | 方建文 | Process for preparing guanidine carbonate |
| CN1385419A (en) * | 2002-06-14 | 2002-12-18 | 方建文 | Process for preparing guanidine hydrochloride |
| CN112707848A (en) * | 2019-10-25 | 2021-04-27 | 方建文 | Preparation method of guanidine hydrochloride |
| CN111302977A (en) * | 2020-03-18 | 2020-06-19 | 湖南吴赣药业有限公司 | Purification method of pharmaceutical grade guanidine hydrochloride |
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