CN112876393A - Method for continuously synthesizing and purifying thiourea by using ammonium thiocyanate - Google Patents
Method for continuously synthesizing and purifying thiourea by using ammonium thiocyanate Download PDFInfo
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- CN112876393A CN112876393A CN202110066400.2A CN202110066400A CN112876393A CN 112876393 A CN112876393 A CN 112876393A CN 202110066400 A CN202110066400 A CN 202110066400A CN 112876393 A CN112876393 A CN 112876393A
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- thiourea
- ammonium thiocyanate
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- UMGDCJDMYOKAJW-UHFFFAOYSA-N thiourea Chemical compound NC(N)=S UMGDCJDMYOKAJW-UHFFFAOYSA-N 0.000 title claims abstract description 178
- SOIFLUNRINLCBN-UHFFFAOYSA-N ammonium thiocyanate Chemical compound [NH4+].[S-]C#N SOIFLUNRINLCBN-UHFFFAOYSA-N 0.000 title claims abstract description 93
- XSQUKJJJFZCRTK-UHFFFAOYSA-N Urea Natural products NC(N)=O XSQUKJJJFZCRTK-UHFFFAOYSA-N 0.000 title claims abstract description 89
- 238000000034 method Methods 0.000 title claims abstract description 31
- 230000002194 synthesizing effect Effects 0.000 title claims abstract description 5
- 238000006243 chemical reaction Methods 0.000 claims abstract description 48
- NWUYHJFMYQTDRP-UHFFFAOYSA-N 1,2-bis(ethenyl)benzene;1-ethenyl-2-ethylbenzene;styrene Chemical compound C=CC1=CC=CC=C1.CCC1=CC=CC=C1C=C.C=CC1=CC=CC=C1C=C NWUYHJFMYQTDRP-UHFFFAOYSA-N 0.000 claims abstract description 11
- 239000003456 ion exchange resin Substances 0.000 claims abstract description 11
- 229920003303 ion-exchange polymer Polymers 0.000 claims abstract description 11
- 238000001035 drying Methods 0.000 claims abstract description 5
- 239000000243 solution Substances 0.000 claims description 73
- 239000003957 anion exchange resin Substances 0.000 claims description 30
- 239000007864 aqueous solution Substances 0.000 claims description 21
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 claims description 16
- PPBRXRYQALVLMV-UHFFFAOYSA-N Styrene Chemical compound C=CC1=CC=CC=C1 PPBRXRYQALVLMV-UHFFFAOYSA-N 0.000 claims description 16
- 238000001179 sorption measurement Methods 0.000 claims description 14
- 239000000203 mixture Substances 0.000 claims description 13
- 239000011259 mixed solution Substances 0.000 claims description 11
- NIXOWILDQLNWCW-UHFFFAOYSA-N acrylic acid group Chemical group C(C=C)(=O)O NIXOWILDQLNWCW-UHFFFAOYSA-N 0.000 claims description 10
- NBIIXXVUZAFLBC-UHFFFAOYSA-N Phosphoric acid Chemical compound OP(O)(O)=O NBIIXXVUZAFLBC-UHFFFAOYSA-N 0.000 claims description 6
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 claims description 6
- 150000007522 mineralic acids Chemical class 0.000 claims description 6
- 150000003839 salts Chemical class 0.000 claims description 6
- KGBXLFKZBHKPEV-UHFFFAOYSA-N boric acid Chemical compound OB(O)O KGBXLFKZBHKPEV-UHFFFAOYSA-N 0.000 claims description 4
- 239000004327 boric acid Substances 0.000 claims description 4
- 230000014759 maintenance of location Effects 0.000 claims description 4
- 229910000147 aluminium phosphate Inorganic materials 0.000 claims description 3
- LFVGISIMTYGQHF-UHFFFAOYSA-N ammonium dihydrogen phosphate Chemical compound [NH4+].OP(O)([O-])=O LFVGISIMTYGQHF-UHFFFAOYSA-N 0.000 claims description 3
- 229910000387 ammonium dihydrogen phosphate Inorganic materials 0.000 claims description 3
- 235000019837 monoammonium phosphate Nutrition 0.000 claims description 3
- 235000010338 boric acid Nutrition 0.000 claims description 2
- 235000011167 hydrochloric acid Nutrition 0.000 claims description 2
- 238000002347 injection Methods 0.000 claims description 2
- 239000007924 injection Substances 0.000 claims description 2
- 229910000402 monopotassium phosphate Inorganic materials 0.000 claims description 2
- 235000019796 monopotassium phosphate Nutrition 0.000 claims description 2
- 235000011007 phosphoric acid Nutrition 0.000 claims description 2
- GNSKLFRGEWLPPA-UHFFFAOYSA-M potassium dihydrogen phosphate Chemical compound [K+].OP(O)([O-])=O GNSKLFRGEWLPPA-UHFFFAOYSA-M 0.000 claims description 2
- LWIHDJKSTIGBAC-UHFFFAOYSA-K potassium phosphate Substances [K+].[K+].[K+].[O-]P([O-])([O-])=O LWIHDJKSTIGBAC-UHFFFAOYSA-K 0.000 claims description 2
- 230000002829 reductive effect Effects 0.000 abstract description 11
- 239000002994 raw material Substances 0.000 abstract description 8
- 238000004519 manufacturing process Methods 0.000 abstract description 5
- 230000007613 environmental effect Effects 0.000 abstract description 3
- 238000009776 industrial production Methods 0.000 abstract description 3
- 238000005406 washing Methods 0.000 abstract description 2
- 239000011347 resin Substances 0.000 description 12
- 229920005989 resin Polymers 0.000 description 12
- 238000011084 recovery Methods 0.000 description 11
- VHUUQVKOLVNVRT-UHFFFAOYSA-N Ammonium hydroxide Chemical compound [NH4+].[OH-] VHUUQVKOLVNVRT-UHFFFAOYSA-N 0.000 description 10
- 235000011114 ammonium hydroxide Nutrition 0.000 description 10
- 150000003440 styrenes Chemical class 0.000 description 10
- 230000035484 reaction time Effects 0.000 description 9
- 239000000047 product Substances 0.000 description 8
- 238000003786 synthesis reaction Methods 0.000 description 5
- ODINCKMPIJJUCX-UHFFFAOYSA-N Calcium oxide Chemical compound [Ca]=O ODINCKMPIJJUCX-UHFFFAOYSA-N 0.000 description 4
- 238000004821 distillation Methods 0.000 description 4
- 238000000926 separation method Methods 0.000 description 4
- 235000008733 Citrus aurantifolia Nutrition 0.000 description 3
- 235000011941 Tilia x europaea Nutrition 0.000 description 3
- 230000015572 biosynthetic process Effects 0.000 description 3
- MYFXBBAEXORJNB-UHFFFAOYSA-N calcium cyanamide Chemical compound [Ca+2].[N-]=C=[N-] MYFXBBAEXORJNB-UHFFFAOYSA-N 0.000 description 3
- 230000001276 controlling effect Effects 0.000 description 3
- 239000013078 crystal Substances 0.000 description 3
- 239000004571 lime Substances 0.000 description 3
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 3
- MVXMNHYVCLMLDD-UHFFFAOYSA-N 4-methoxynaphthalene-1-carbaldehyde Chemical compound C1=CC=C2C(OC)=CC=C(C=O)C2=C1 MVXMNHYVCLMLDD-UHFFFAOYSA-N 0.000 description 2
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 2
- 239000005997 Calcium carbide Substances 0.000 description 2
- VZCYOOQTPOCHFL-OWOJBTEDSA-N Fumaric acid Chemical compound OC(=O)\C=C\C(O)=O VZCYOOQTPOCHFL-OWOJBTEDSA-N 0.000 description 2
- CTQNGGLPUBDAKN-UHFFFAOYSA-N O-Xylene Chemical compound CC1=CC=CC=C1C CTQNGGLPUBDAKN-UHFFFAOYSA-N 0.000 description 2
- UCKMPCXJQFINFW-UHFFFAOYSA-N Sulphide Chemical compound [S-2] UCKMPCXJQFINFW-UHFFFAOYSA-N 0.000 description 2
- 239000000292 calcium oxide Substances 0.000 description 2
- 235000012255 calcium oxide Nutrition 0.000 description 2
- PEHRWUQXQPNJCM-UHFFFAOYSA-N cyanoazanium sulfanide Chemical compound [SH-].[NH3+]C#N PEHRWUQXQPNJCM-UHFFFAOYSA-N 0.000 description 2
- 238000005265 energy consumption Methods 0.000 description 2
- 239000012535 impurity Substances 0.000 description 2
- 239000003112 inhibitor Substances 0.000 description 2
- 230000000670 limiting effect Effects 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 229910052751 metal Inorganic materials 0.000 description 2
- 239000002184 metal Substances 0.000 description 2
- -1 nitrogen-calcium hydrosulfide Chemical compound 0.000 description 2
- 230000036961 partial effect Effects 0.000 description 2
- 238000000746 purification Methods 0.000 description 2
- 238000001308 synthesis method Methods 0.000 description 2
- CLZWAWBPWVRRGI-UHFFFAOYSA-N tert-butyl 2-[2-[2-[2-[bis[2-[(2-methylpropan-2-yl)oxy]-2-oxoethyl]amino]-5-bromophenoxy]ethoxy]-4-methyl-n-[2-[(2-methylpropan-2-yl)oxy]-2-oxoethyl]anilino]acetate Chemical compound CC1=CC=C(N(CC(=O)OC(C)(C)C)CC(=O)OC(C)(C)C)C(OCCOC=2C(=CC=C(Br)C=2)N(CC(=O)OC(C)(C)C)CC(=O)OC(C)(C)C)=C1 CLZWAWBPWVRRGI-UHFFFAOYSA-N 0.000 description 2
- 239000008096 xylene Substances 0.000 description 2
- 241000894006 Bacteria Species 0.000 description 1
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 description 1
- FFEARJCKVFRZRR-BYPYZUCNSA-N L-methionine Chemical compound CSCC[C@H](N)C(O)=O FFEARJCKVFRZRR-BYPYZUCNSA-N 0.000 description 1
- ZRVUJXDFFKFLMG-UHFFFAOYSA-N Meloxicam Chemical compound OC=1C2=CC=CC=C2S(=O)(=O)N(C)C=1C(=O)NC1=NC=C(C)S1 ZRVUJXDFFKFLMG-UHFFFAOYSA-N 0.000 description 1
- PVLJETXTTWAYEW-UHFFFAOYSA-N Mizolastine Chemical compound N=1C=CC(=O)NC=1N(C)C(CC1)CCN1C1=NC2=CC=CC=C2N1CC1=CC=C(F)C=C1 PVLJETXTTWAYEW-UHFFFAOYSA-N 0.000 description 1
- IOVCWXUNBOPUCH-UHFFFAOYSA-M Nitrite anion Chemical compound [O-]N=O IOVCWXUNBOPUCH-UHFFFAOYSA-M 0.000 description 1
- LGRFSURHDFAFJT-UHFFFAOYSA-N Phthalic anhydride Natural products C1=CC=C2C(=O)OC(=O)C2=C1 LGRFSURHDFAFJT-UHFFFAOYSA-N 0.000 description 1
- 230000000844 anti-bacterial effect Effects 0.000 description 1
- 239000003899 bactericide agent Substances 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- JHIWVOJDXOSYLW-UHFFFAOYSA-N butyl 2,2-difluorocyclopropane-1-carboxylate Chemical compound CCCCOC(=O)C1CC1(F)F JHIWVOJDXOSYLW-UHFFFAOYSA-N 0.000 description 1
- YAECNLICDQSIKA-UHFFFAOYSA-L calcium;sulfanide Chemical compound [SH-].[SH-].[Ca+2] YAECNLICDQSIKA-UHFFFAOYSA-L 0.000 description 1
- 239000003054 catalyst Substances 0.000 description 1
- 238000003889 chemical engineering Methods 0.000 description 1
- 239000013064 chemical raw material Substances 0.000 description 1
- 239000012295 chemical reaction liquid Substances 0.000 description 1
- 239000007795 chemical reaction product Substances 0.000 description 1
- 239000003153 chemical reaction reagent Substances 0.000 description 1
- 238000004140 cleaning Methods 0.000 description 1
- 239000011248 coating agent Substances 0.000 description 1
- 238000000576 coating method Methods 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
- 238000010924 continuous production Methods 0.000 description 1
- 238000001816 cooling Methods 0.000 description 1
- 239000000498 cooling water Substances 0.000 description 1
- 238000005260 corrosion Methods 0.000 description 1
- 230000007797 corrosion Effects 0.000 description 1
- 238000010908 decantation Methods 0.000 description 1
- 238000003795 desorption Methods 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 125000000664 diazo group Chemical group [N-]=[N+]=[*] 0.000 description 1
- 239000012153 distilled water Substances 0.000 description 1
- 229940079593 drug Drugs 0.000 description 1
- 239000003814 drug Substances 0.000 description 1
- 239000000975 dye Substances 0.000 description 1
- 229920001971 elastomer Polymers 0.000 description 1
- XUFQPHANEAPEMJ-UHFFFAOYSA-N famotidine Chemical compound NC(N)=NC1=NC(CSCCC(N)=NS(N)(=O)=O)=CS1 XUFQPHANEAPEMJ-UHFFFAOYSA-N 0.000 description 1
- 229960001596 famotidine Drugs 0.000 description 1
- 239000003337 fertilizer Substances 0.000 description 1
- 239000008396 flotation agent Substances 0.000 description 1
- 239000001530 fumaric acid Substances 0.000 description 1
- 239000007789 gas Substances 0.000 description 1
- 230000035784 germination Effects 0.000 description 1
- 238000000227 grinding Methods 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 230000002401 inhibitory effect Effects 0.000 description 1
- 229910052500 inorganic mineral Inorganic materials 0.000 description 1
- 239000000543 intermediate Substances 0.000 description 1
- 238000005342 ion exchange Methods 0.000 description 1
- JEIPFZHSYJVQDO-UHFFFAOYSA-N iron(III) oxide Inorganic materials O=[Fe]O[Fe]=O JEIPFZHSYJVQDO-UHFFFAOYSA-N 0.000 description 1
- 238000006317 isomerization reaction Methods 0.000 description 1
- 229960001929 meloxicam Drugs 0.000 description 1
- 229930182817 methionine Natural products 0.000 description 1
- 239000008267 milk Substances 0.000 description 1
- 210000004080 milk Anatomy 0.000 description 1
- 235000013336 milk Nutrition 0.000 description 1
- 239000011707 mineral Substances 0.000 description 1
- 235000010755 mineral Nutrition 0.000 description 1
- 229960001144 mizolastine Drugs 0.000 description 1
- 239000012452 mother liquor Substances 0.000 description 1
- 238000000465 moulding Methods 0.000 description 1
- 229910052757 nitrogen Inorganic materials 0.000 description 1
- 239000000618 nitrogen fertilizer Substances 0.000 description 1
- 239000000843 powder Substances 0.000 description 1
- 238000002360 preparation method Methods 0.000 description 1
- 230000001105 regulatory effect Effects 0.000 description 1
- 229920006395 saturated elastomer Polymers 0.000 description 1
- 239000002689 soil Substances 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 238000001694 spray drying Methods 0.000 description 1
- JNMRHUJNCSQMMB-UHFFFAOYSA-N sulfathiazole Chemical compound C1=CC(N)=CC=C1S(=O)(=O)NC1=NC=CS1 JNMRHUJNCSQMMB-UHFFFAOYSA-N 0.000 description 1
- 229960001544 sulfathiazole Drugs 0.000 description 1
- 239000000057 synthetic resin Substances 0.000 description 1
- 229920003002 synthetic resin Polymers 0.000 description 1
- VZCYOOQTPOCHFL-UHFFFAOYSA-N trans-butenedioic acid Natural products OC(=O)C=CC(O)=O VZCYOOQTPOCHFL-UHFFFAOYSA-N 0.000 description 1
- 238000004073 vulcanization Methods 0.000 description 1
Images
Classifications
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C335/00—Thioureas, i.e. compounds containing any of the groups, the nitrogen atoms not being part of nitro or nitroso groups
- C07C335/02—Thiourea
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01C—AMMONIA; CYANOGEN; COMPOUNDS THEREOF
- C01C3/00—Cyanogen; Compounds thereof
- C01C3/20—Thiocyanic acid; Salts thereof
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- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Inorganic Chemistry (AREA)
- Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
Abstract
A method for continuously synthesizing and purifying thiourea by using ammonium thiocyanate comprises the following steps: (1) the method has the advantages that the ammonium thiocyanate is used as a raw material, a continuous flow device is used for reaction, reaction conditions are optimized, the reaction efficiency is high, and the yield of thiourea is improved to 48.3%; (2) and pouring the reacted solution into an ion exchange resin column, washing, concentrating under reduced pressure, and drying to obtain the high-purity thiourea. The method has the advantages of simple and reasonable process, high atom utilization rate of raw materials, environmental friendliness, good product quality, short production period, convenience in operation, lower cost and suitability for industrial production.
Description
Technical Field
The invention belongs to the technical field of chemical engineering, relates to the field of chemical synthesis and compound separation, and particularly relates to a continuous production method for preparing thiourea from ammonium thiocyanate and separation of ammonium thiocyanate and thiourea.
Background
Thiourea is a white and shiny crystal, bitter in taste. Thiourea is an important chemical raw material and has extremely wide application in industrial production and life. The thiourea is used as a raw material for preparing medicines such as sulfathiazole, methionine, pig slices and the like, can also be used for producing medical intermediates such as aminothiazoly loximate, meloxicam, famotidine, mizolastine and the like, and is used as a raw material for dyes, resins and molding powder. It can also be used as flotation agent of metal mineral, vulcanization accelerator of rubber, catalyst for preparing phthalic anhydride and fumaric acid, nitrogen fertilizer synergist for inhibiting growth of nitrite bacteria in soil, and metal rust inhibitor and cleaning corrosion inhibitor. Thiourea is also used in many fields such as diazo-sensitive paper, synthetic resin coating, anion exchange resin, germination accelerator, bactericide, etc. Thiourea is also used as a fertilizer. In the field of photographic materials, it can be used as developer and toner.
Currently, the methods for industrially producing thiourea mainly include lime nitrogen-calcium hydrosulfide synthesis and cyanamide-hydrogen sulfide synthesis. The synthesis method of lime nitrogen-calcium hydrosulfide uses quick lime, calcium cyanamide (lime nitrogen) and sulfide as raw material to synthesize thiourea, and firstly uses quick lime and water to uniformly mix them to obtain lime milk, then uses H prepared by sulfide to make synthesis2S gas, and reacting the generated calcium hydrosulfide with calcium cyanamide to obtain thiourea solution. Since calcium carbide is mostly used for producing lime nitrogen industrially, not only is the production cost higher, but also the calcium carbide and the lime nitrogen belong to products with high energy consumption and high pollution, so the production cost is high and the environmental cost is high. The cyanamide-hydrogen sulfide synthesis method has complex process and high cost.
The preparation of thiourea by ammonium thiocyanate isomerization is a relatively old process, and the specific process is as follows: the ammonium thiocyanate raw material is subjected to partial pressure distillation in a reaction kettle, nitrogen is introduced during distillation as an entrainer, and most of distilled water is taken away. Then, partial pressure distillation was carried out using xylene as an entrainer until the solution was saturated. Heating was continued until almost all the water had evaporated. And then, continuously raising the temperature to keep the reaction temperature between 145 and 155 ℃ until the reaction reaches the equilibrium. Removing xylene by decantation and distillation, granulating the isomerized product by flaking, spray drying, solidifying and grinding, pouring into mother liquor, cooling and crystallizing to obtain mixed crystal of thiourea and ammonium thiocyanate, and washing ammonium thiocyanate with cooling water at 0 ℃ to obtain thiourea. Then centrifugal separation is carried out by a centrifugal machine to separate out thiourea solid. Recrystallizing the precipitated thiourea with absolute ethyl alcohol to obtain thiourea crystals, and drying to obtain the finished thiourea product. The method has the problems of large electric energy consumption and difficult separation of ammonium thiocyanate and thiourea.
Disclosure of Invention
The invention aims to provide a method for continuously producing thiourea by using ammonium thiocyanate and then using ion exchange resinAdsorption of SCN in ammonium thiocyanate-The thiourea is separated from the thiourea, concentrated and purified to obtain the thiourea with high purity and less impurities, and the high-purity ammonium thiocyanate can be obtained by concentration and purification after resin desorption is repeatedly utilized.
In order to achieve the above purpose of the invention, the following technical scheme is adopted:
a process for the continuous synthesis and purification of thiourea from ammonium thiocyanate, said process comprising the steps of:
(1) continuously injecting an ammonium thiocyanate aqueous solution with the concentration of 20.0-200.0g/L into a tubular reactor for reaction, wherein the temperature in the tubular reactor is 40-180 ℃, and the retention time is 10-180min, so as to obtain a mixed solution of ammonium thiocyanate and thiourea;
(2) and (2) adjusting the pH value of the mixed solution of ammonium thiocyanate and thiourea obtained in the step (1) by using inorganic acid and salt, wherein the pH value is 2.0-6.5, injecting the mixed solution into an adsorption column filled with ion exchange resin at a rate of 0.1-10mL/min, and drying the solution which flows out of the column to obtain a thiourea product.
Further, in the step (1), the concentration of the ammonium thiocyanate in the ammonium thiocyanate aqueous solution is 30.0-160.0 g/L.
In the step (1), the retention time is 10-60 min.
In the step (1), the temperature in the tubular reactor is 80-160 ℃.
Still further, in the step (2), the inorganic acid and salt include: sulfuric acid, hydrochloric acid, phosphoric acid, boric acid, monopotassium phosphate or ammonium dihydrogen phosphate, preferably hydrochloric acid.
In the step (2), the pH value of the mixed solution of ammonium thiocyanate and thiourea is adjusted to 4.0-6.0 by using inorganic acid and salt.
In the step (2), the ion exchange resin is one or a mixture of two or more of gel type styrene series strong base anion exchange resin, macroporous styrene series strong base anion exchange resin, gel type styrene series weak base anion exchange resin, macroporous styrene series weak base anion exchange resin, gel type acrylic acid series strong base anion exchange resin, macroporous acrylic acid series strong base anion exchange resin, gel type acrylic acid series weak base anion exchange resin and macroporous acrylic acid series weak base anion exchange resin.
The ion exchange resin is 201 multiplied by 7 gel type styrene strong base anion exchange resin.
In the step (2), the injection speed of the mixed solution is that the speed of the mixed solution flowing through each gram of ion exchange resin is 0.5-8 mL/min.
The method takes ammonium thiocyanate as a raw material, the reaction product contains ammonium thiocyanate and thiourea, the ammonium thiocyanate and the thiourea are separated by ion exchange resin, and the separated ammonium thiocyanate can be continuously reacted and recycled, so that the cost is saved.
Compared with the prior art, the invention has the beneficial effects that:
(1) the method for continuously producing the thiourea by using the isocompositional ammonium thiocyanate has the advantages of simple and reasonable process, high atom utilization rate of raw materials, environmental friendliness, high production efficiency and the like; and the product has good quality, short production period, convenient operation and lower cost, and is suitable for industrial production.
(2) The method for preparing thiourea from ammonium thiocyanate utilizes ion exchange resin to efficiently separate the ammonium thiocyanate and the thiourea, obtains a thiourea product with high purity and less impurities, and can recover the ammonium thiocyanate.
Drawings
FIG. 1 is a process flow diagram (1-ammonium thiocyanate aqueous solution, 2-reaction solution, 3-thiourea solution, 4-tubular reactor, 5-adsorption column, 6-pump, 7-valve). Remarking: the pipeline of the tubular reactor is made of 316L material, phi is 4 multiplied by 0.5, and the length is 20 m; the size of the column is 38X 500 mm. The specific process flow is as follows: the ammonium thiocyanate aqueous solution stays in the tubular reactor for reaction for a period of time, and the obtained reaction liquid is conveyed to an adsorption column at a certain flow rate to adsorb SCN-And the solution leaving the column is the purified thiourea solution, and the thiourea product is obtained after concentration and drying.
Detailed Description
The following examples, which are included to further illustrate the invention and are not to be construed as limiting the invention in any way, are included as part of the specification and are intended to be included as part of the specification. The reagents or instruments used are not indicated by the manufacturer, but are conventional commercial products available commercially.
Example 1
Preparing 20.0g/L ammonium thiocyanate aqueous solution, injecting the ammonium thiocyanate aqueous solution into a tubular reactor by a pump for reaction, keeping the reaction time at 180min, adjusting the pH of the reaction solution to 2.0 by using sulfuric acid, introducing the reaction solution into a column filled with 140.2g of 213 gel type acrylic acid series strong base anion exchange resin for adsorption, and passing through the column at the speed of flowing through each gram of resin at 0.1mL/min to obtain thiourea solution S1. Then desorbing the mixture by using the prepared ammonia water solution to obtain an ammonium thiocyanate solution S2. The solutions S1 and S2 were concentrated under reduced pressure, respectively, and then dried to obtain high-purity thiourea and ammonium thiocyanate. The yield of thiourea was 28.4%, the recovery of ammonium thiocyanate was 58.1%, the purity of thiourea reached 98.0%, and the purity of ammonium thiocyanate reached 98.1%.
Example 2
Preparing 30.0g/L ammonium thiocyanate aqueous solution, injecting the solution into a tubular reactor by a pump for reaction, keeping the reaction time at 80 ℃ for 60min, adjusting the pH of the reaction solution to 4.0 by using phosphoric acid, introducing the reaction solution into a column filled with 140.6g of 201 x 4 gel type styrene series strong base anion exchange resin for adsorption, and passing through the column at the speed of flowing through each gram of resin at 0.5mL/min to obtain thiourea solution S1. Then desorbing the mixture by using the prepared ammonia water solution to obtain an ammonium thiocyanate solution S2. The solutions S1 and S2 were concentrated under reduced pressure, respectively, and then dried to obtain high-purity thiourea and ammonium thiocyanate. The yield of thiourea was 34.3%, the recovery of ammonium thiocyanate was 53.1%, the purity of thiourea reached 98.5%, and the purity of ammonium thiocyanate reached 98.0%.
Example 3
Preparing 40.6g/L ammonium thiocyanate aqueous solution, injecting the aqueous solution into a tubular reactor by a pump for reaction, keeping the reaction time for 10min, controlling the reaction temperature to be 40 ℃, adjusting the pH of the reaction solution to be 6.0 by boric acid, introducing the reaction solution into a column filled with 140.3g of 201 x 4 gel type styrene series strong base anion exchange resin for adsorption, and passing through the column at the speed of flowing through per gram of resin by 2mL/min to obtain thiourea solution S1. Then desorbing the mixture by using the prepared ammonia water solution to obtain an ammonium thiocyanate solution S2. The solutions S1 and S2 were concentrated under reduced pressure, respectively, and then dried to obtain high-purity thiourea and ammonium thiocyanate. The yield of thiourea is 20.6%, the recovery rate of ammonium thiocyanate is 60.9%, the purity of thiourea reaches 98.6%, and the purity of ammonium thiocyanate reaches 98.8%.
Example 4
Preparing 50.4g/L ammonium thiocyanate aqueous solution, injecting the solution into a tubular reactor by a pump for reaction, keeping the reaction time at 40min, controlling the reaction temperature at 160 ℃, adjusting the pH of the reaction solution to 6.5 by ammonium dihydrogen phosphate, introducing the reaction solution into a column filled with 140.4g of HZ-338 gel type styrene weak base anion exchange resin for adsorption, and passing through the column at the speed of 2mL/min flowing through per gram of resin to obtain thiourea solution S1. Then desorbing the mixture by using the prepared ammonia water solution to obtain an ammonium thiocyanate solution S2. The solutions S1 and S2 were concentrated under reduced pressure, respectively, and then dried to obtain high-purity thiourea and ammonium thiocyanate. The yield of thiourea was 37.8%, the recovery of ammonium thiocyanate was 45.3%, the purity of thiourea reached 98.6%, and the purity of ammonium thiocyanate reached 98.8%.
Example 5
Preparing 58.4g/L ammonium thiocyanate aqueous solution, injecting the ammonium thiocyanate aqueous solution into a tubular reactor by a pump for reaction, keeping the reaction time for 30min, adjusting the pH of the reaction solution to 4.5 by hydrochloric acid at the reaction temperature of 90 ℃, introducing the reaction solution into a column filled with 139.8g of 201 x 7 gel type styrene series strong base anion exchange resin for adsorption, and passing through the column at the speed of flowing through each gram of resin at 10mL/min to obtain thiourea solution S1. Then desorbing the mixture by using the prepared ammonia water solution to obtain an ammonium thiocyanate solution S2. The solutions S1 and S2 were concentrated under reduced pressure, respectively, and then dried to obtain high-purity thiourea and ammonium thiocyanate. The yield of thiourea was 43.5%, the recovery of ammonium thiocyanate was 46.4%, the purity of thiourea reached 99.2%, and the purity of ammonium thiocyanate reached 99.1%.
Example 6
Preparing 68.0g/L ammonium thiocyanate aqueous solution, injecting the aqueous solution into a tubular reactor by a pump for reaction, wherein the retention time is 40min, the reaction temperature is 100 ℃, regulating the pH of the reaction solution to 5.5 by hydrochloric acid, introducing the reaction solution into a column filled with 140.1g of 201 x 7 gel type styrene series strong base anion exchange resin for adsorption, and passing through the column at the speed of 8mL/min flowing through per gram of resin to obtain thiourea solution S1. Then desorbing the mixture by using the prepared ammonia water solution to obtain an ammonium thiocyanate solution S2. The solutions S1 and S2 were concentrated under reduced pressure, respectively, and then dried to obtain high-purity thiourea and ammonium thiocyanate. The yield of thiourea was 45.7%, the recovery of ammonium thiocyanate was 46.8%, the purity of thiourea reached 99.1%, and the purity of ammonium thiocyanate reached 99.3%.
Example 7
Preparing 91.3g/L ammonium thiocyanate aqueous solution, injecting the aqueous solution into a tubular reactor by a pump for reaction, keeping the reaction time for 30min, adjusting the pH of the reaction solution to 6.0 by hydrochloric acid at the reaction temperature of 120 ℃, introducing the reaction solution into a column filled with 140.4g of 201 x 7 gel type styrene series strong base anion exchange resin for adsorption, and passing through the column at the speed of 4mL/min flowing through per gram of resin to obtain thiourea solution S1. Then desorbing the mixture by using the prepared ammonia water solution to obtain an ammonium thiocyanate solution S2. The solutions S1 and S2 were concentrated under reduced pressure, respectively, and then dried to obtain high-purity thiourea and ammonium thiocyanate. The yield of thiourea was 47.3%, the recovery of ammonium thiocyanate was 45.5%, the purity of thiourea reached 99.4%, and the purity of ammonium thiocyanate reached 99.3%.
Example 8
Preparing 121.8g/L ammonium thiocyanate aqueous solution, injecting the aqueous solution into a tubular reactor by a pump for reaction, keeping the reaction time for 20min, adjusting the pH of the reaction solution to 6.0 by hydrochloric acid at the reaction temperature of 100 ℃, introducing the reaction solution into a column filled with 140.9g of 201 x 7 gel type styrene series strong base anion exchange resin for adsorption, and passing through the column at the speed of flowing through each gram of resin at 2mL/min to obtain thiourea solution S1. Then desorbing the mixture by using the prepared ammonia water solution to obtain an ammonium thiocyanate solution S2. The solutions S1 and S2 were concentrated under reduced pressure, respectively, and then dried to obtain high-purity thiourea and ammonium thiocyanate. The yield of thiourea is 48.3%, the recovery rate of ammonium thiocyanate is 46.2%, the purity of thiourea reaches 99.6%, and the purity of ammonium thiocyanate reaches 99.4%.
Example 9
Preparing 160.0g/L ammonium thiocyanate aqueous solution, injecting the solution into a tubular reactor by a pump for reaction, keeping the reaction time at 35min, controlling the reaction temperature at 110 ℃, adjusting the pH of the reaction solution to 5.0 by hydrochloric acid, introducing the reaction solution into a column filled with 140.1g of D201 macroporous styrene strong base anion exchange resin for adsorption, and passing through the column at the speed of flowing through per gram of resin by 1mL/min to obtain thiourea solution S1. Then desorbing the mixture by using the prepared ammonia water solution to obtain an ammonium thiocyanate solution S2. The solutions S1 and S2 were concentrated under reduced pressure, respectively, and then dried to obtain high-purity thiourea and ammonium thiocyanate. The yield of thiourea was 45.6%, the recovery of ammonium thiocyanate was 45.9%, the purity of thiourea reached 98.2%, and the purity of ammonium thiocyanate reached 98.4%.
Example 10
Preparing 200.0g/L ammonium thiocyanate aqueous solution, injecting the solution into a tubular reactor by a pump for reaction, keeping the reaction time at 140 ℃ for 40min, adjusting the pH of the reaction solution to 5.5 by boric acid, introducing the reaction solution into a column filled with 140.3g of D213 macroporous acrylic acid series strong base anion exchange resin for adsorption, and passing through the column at the speed of flowing through per gram of resin at 1.5mL/min to obtain thiourea solution S1. Then desorbing the mixture by using the prepared ammonia water solution to obtain an ammonium thiocyanate solution S2. The solutions S1 and S2 were concentrated under reduced pressure, respectively, and then dried to obtain high-purity thiourea and ammonium thiocyanate. The yield of thiourea was 44.3%, the recovery of ammonium thiocyanate was 47.5%, the purity of thiourea reached 98.3%, and the purity of ammonium thiocyanate reached 98.6%.
Experimental results show that the method for continuously synthesizing and purifying the thiourea by using the ammonium thiocyanate adopts a tubular reactor for continuous reaction, uses 201 multiplied by 7 gel type styrene strong base anion exchange resin to separate the thiourea and the ammonium thiocyanate, the yield of the thiourea is 48.3 percent, the recovery rate of the ammonium thiocyanate reaches 46.2 percent, and the purities of the thiourea and the recovered ammonium thiocyanate are both more than 98 percent
The above examples are set forth to illustrate the present invention more clearly and should not be construed as limiting the scope of the invention, which is defined in the appended claims to which the present invention pertains, as the skilled in the art will be able to modify various equivalent forms of the present invention after reading the present invention.
Claims (9)
1. A method for continuously synthesizing and purifying thiourea by using ammonium thiocyanate, which is characterized by comprising the following steps:
(1) continuously injecting an ammonium thiocyanate aqueous solution with the concentration of 20.0-200.0g/L into a tubular reactor for reaction, wherein the temperature in the tubular reactor is 40-180 ℃, and the retention time is 10-180min, so as to obtain a mixed solution of ammonium thiocyanate and thiourea;
(2) and (2) adjusting the pH value of the mixed solution of ammonium thiocyanate and thiourea obtained in the step (1) by using inorganic acid and salt, wherein the pH value is 2.0-6.5, injecting the mixed solution into an adsorption column filled with ion exchange resin at a rate of 0.1-10mL/min, and drying the solution which flows out of the column to obtain a thiourea product.
2. The method according to claim 1, wherein in step (1), the concentration of ammonium thiocyanate in the aqueous ammonium thiocyanate solution is from 30.0 to 160.0 g/L.
3. The method according to claim 1 or 2, wherein in step (1), the residence time is 10-60 min.
4. The process according to claim 1 or 2, wherein in step (1), the temperature in the tubular reactor is 80 to 160 ℃.
5. The method according to claim 1, wherein in the step (2), the inorganic acid and salt comprise: sulfuric acid, hydrochloric acid, phosphoric acid, boric acid, monopotassium phosphate or ammonium dihydrogen phosphate.
6. The method according to claim 1, wherein in the step (2), the pH value of the mixed solution of ammonium thiocyanate and thiourea is adjusted to 4.0-6.0 by using inorganic acid and salt.
7. The method according to claim 1, wherein in the step (2), the ion exchange resin is one or a mixture of two or more of gel type styrene strong base anion exchange resin, macroporous styrene strong base anion exchange resin, gel type styrene weak base anion exchange resin, macroporous styrene weak base anion exchange resin, gel type acrylic strong base anion exchange resin, macroporous acrylic strong base anion exchange resin, gel type acrylic weak base anion exchange resin, and macroporous acrylic weak base anion exchange resin.
8. The method of claim 7, wherein the ion exchange resin is a 201 x 7 gel type styrenic strong base anion exchange resin.
9. The method according to claim 1, wherein in the step (2), the injection rate of the mixed solution is 0.5-8mL/min per gram of the ion exchange resin.
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| CN114307359A (en) * | 2021-11-12 | 2022-04-12 | 格林智慧环保科技(山西)有限公司 | Membrane separation method of thiourea and calcium thiocyanate |
| CN115448863A (en) * | 2022-10-09 | 2022-12-09 | 浙江迪邦化工有限公司 | Continuous preparation process of 3, 4-dichlorophenyl thiourea |
| CN115819305A (en) * | 2022-10-09 | 2023-03-21 | 浙江迪邦化工有限公司 | Continuous preparation process of p-nitrophenylthiourea |
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| CN115448863B (en) * | 2022-10-09 | 2024-03-26 | 浙江迪邦化工有限公司 | Continuous preparation process of 3, 4-dichlorophenyl thiourea |
| CN115819305B (en) * | 2022-10-09 | 2024-06-07 | 浙江迪邦化工有限公司 | Continuous preparation process of p-nitrophenyl thiourea |
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