CN114874117A - Process for preparing thiourea dioxide by carbon dioxide solvent method - Google Patents
Process for preparing thiourea dioxide by carbon dioxide solvent method Download PDFInfo
- Publication number
- CN114874117A CN114874117A CN202210420886.XA CN202210420886A CN114874117A CN 114874117 A CN114874117 A CN 114874117A CN 202210420886 A CN202210420886 A CN 202210420886A CN 114874117 A CN114874117 A CN 114874117A
- Authority
- CN
- China
- Prior art keywords
- thiourea
- carbon dioxide
- dioxide
- aqueous solution
- preparing
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 title claims abstract description 107
- 239000001569 carbon dioxide Substances 0.000 title claims abstract description 44
- 229910002092 carbon dioxide Inorganic materials 0.000 title claims abstract description 44
- RYYXDZDBXNUPOG-UHFFFAOYSA-N 4,5,6,7-tetrahydro-1,3-benzothiazole-2,6-diamine;dihydrochloride Chemical compound Cl.Cl.C1C(N)CCC2=C1SC(N)=N2 RYYXDZDBXNUPOG-UHFFFAOYSA-N 0.000 title claims abstract description 33
- 238000000034 method Methods 0.000 title claims abstract description 20
- 238000004519 manufacturing process Methods 0.000 title claims abstract description 15
- 239000002904 solvent Substances 0.000 title claims abstract description 15
- UMGDCJDMYOKAJW-UHFFFAOYSA-N thiourea Chemical compound NC(N)=S UMGDCJDMYOKAJW-UHFFFAOYSA-N 0.000 claims abstract description 86
- XSQUKJJJFZCRTK-UHFFFAOYSA-N Urea Natural products NC(N)=O XSQUKJJJFZCRTK-UHFFFAOYSA-N 0.000 claims abstract description 43
- MHAJPDPJQMAIIY-UHFFFAOYSA-N Hydrogen peroxide Chemical compound OO MHAJPDPJQMAIIY-UHFFFAOYSA-N 0.000 claims abstract description 40
- 238000006243 chemical reaction Methods 0.000 claims abstract description 38
- 239000007864 aqueous solution Substances 0.000 claims abstract description 19
- 235000011089 carbon dioxide Nutrition 0.000 claims abstract description 16
- 239000007788 liquid Substances 0.000 claims abstract description 15
- 238000003756 stirring Methods 0.000 claims abstract description 7
- 238000001035 drying Methods 0.000 claims abstract description 5
- 230000032683 aging Effects 0.000 claims abstract description 4
- 239000012467 final product Substances 0.000 claims abstract description 3
- 239000002994 raw material Substances 0.000 claims description 7
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 abstract description 26
- 230000035484 reaction time Effects 0.000 abstract description 4
- 230000001590 oxidative effect Effects 0.000 abstract 1
- 239000000047 product Substances 0.000 description 17
- 239000000243 solution Substances 0.000 description 15
- -1 cetyl alcohol ester Chemical class 0.000 description 9
- 239000007789 gas Substances 0.000 description 9
- 238000004448 titration Methods 0.000 description 9
- 238000005259 measurement Methods 0.000 description 6
- AKHNMLFCWUSKQB-UHFFFAOYSA-L sodium thiosulfate Chemical compound [Na+].[Na+].[O-]S([O-])(=O)=S AKHNMLFCWUSKQB-UHFFFAOYSA-L 0.000 description 6
- 235000019345 sodium thiosulphate Nutrition 0.000 description 6
- ZCYVEMRRCGMTRW-UHFFFAOYSA-N 7553-56-2 Chemical compound [I] ZCYVEMRRCGMTRW-UHFFFAOYSA-N 0.000 description 5
- 229910052740 iodine Inorganic materials 0.000 description 5
- 239000011630 iodine Substances 0.000 description 5
- UIIMBOGNXHQVGW-UHFFFAOYSA-M Sodium bicarbonate Chemical compound [Na+].OC([O-])=O UIIMBOGNXHQVGW-UHFFFAOYSA-M 0.000 description 4
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 description 4
- 229960000541 cetyl alcohol Drugs 0.000 description 4
- BXWNKGSJHAJOGX-UHFFFAOYSA-N n-hexadecyl alcohol Natural products CCCCCCCCCCCCCCCCO BXWNKGSJHAJOGX-UHFFFAOYSA-N 0.000 description 4
- 239000012085 test solution Substances 0.000 description 4
- 230000000694 effects Effects 0.000 description 3
- 239000011521 glass Substances 0.000 description 3
- 238000002360 preparation method Methods 0.000 description 3
- 238000005057 refrigeration Methods 0.000 description 3
- 241001411320 Eriogonum inflatum Species 0.000 description 2
- 229920002472 Starch Polymers 0.000 description 2
- 238000010521 absorption reaction Methods 0.000 description 2
- 230000002378 acidificating effect Effects 0.000 description 2
- 238000004458 analytical method Methods 0.000 description 2
- 239000006227 byproduct Substances 0.000 description 2
- 238000004364 calculation method Methods 0.000 description 2
- 239000003153 chemical reaction reagent Substances 0.000 description 2
- 238000000354 decomposition reaction Methods 0.000 description 2
- 230000007547 defect Effects 0.000 description 2
- 238000009776 industrial production Methods 0.000 description 2
- 239000011261 inert gas Substances 0.000 description 2
- 238000000926 separation method Methods 0.000 description 2
- 238000007086 side reaction Methods 0.000 description 2
- 239000000779 smoke Substances 0.000 description 2
- 229910000030 sodium bicarbonate Inorganic materials 0.000 description 2
- 235000017557 sodium bicarbonate Nutrition 0.000 description 2
- 235000019698 starch Nutrition 0.000 description 2
- 239000008107 starch Substances 0.000 description 2
- 238000003860 storage Methods 0.000 description 2
- 238000003786 synthesis reaction Methods 0.000 description 2
- 238000012360 testing method Methods 0.000 description 2
- 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 1
- ATRRKUHOCOJYRX-UHFFFAOYSA-N Ammonium bicarbonate Chemical compound [NH4+].OC([O-])=O ATRRKUHOCOJYRX-UHFFFAOYSA-N 0.000 description 1
- CBENFWSGALASAD-UHFFFAOYSA-N Ozone Chemical compound [O-][O+]=O CBENFWSGALASAD-UHFFFAOYSA-N 0.000 description 1
- NINIDFKCEFEMDL-UHFFFAOYSA-N Sulfur Chemical compound [S] NINIDFKCEFEMDL-UHFFFAOYSA-N 0.000 description 1
- 239000002253 acid Substances 0.000 description 1
- 239000001099 ammonium carbonate Substances 0.000 description 1
- 235000012501 ammonium carbonate Nutrition 0.000 description 1
- UYJXRRSPUVSSMN-UHFFFAOYSA-P ammonium sulfide Chemical compound [NH4+].[NH4+].[S-2] UYJXRRSPUVSSMN-UHFFFAOYSA-P 0.000 description 1
- 239000003963 antioxidant agent Substances 0.000 description 1
- 230000003078 antioxidant effect Effects 0.000 description 1
- 239000003125 aqueous solvent Substances 0.000 description 1
- 238000003556 assay Methods 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 238000004061 bleaching Methods 0.000 description 1
- 239000003054 catalyst Substances 0.000 description 1
- 238000005119 centrifugation Methods 0.000 description 1
- 239000003638 chemical reducing agent Substances 0.000 description 1
- 239000003795 chemical substances by application Substances 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 239000008367 deionised water Substances 0.000 description 1
- 229910021641 deionized water Inorganic materials 0.000 description 1
- 238000007865 diluting Methods 0.000 description 1
- 238000004043 dyeing Methods 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- 239000003517 fume Substances 0.000 description 1
- 238000002309 gasification Methods 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 239000012535 impurity Substances 0.000 description 1
- 239000012442 inert solvent Substances 0.000 description 1
- 150000002484 inorganic compounds Chemical class 0.000 description 1
- 229910010272 inorganic material Inorganic materials 0.000 description 1
- 238000012423 maintenance Methods 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 238000010907 mechanical stirring Methods 0.000 description 1
- VUZPPFZMUPKLLV-UHFFFAOYSA-N methane;hydrate Chemical compound C.O VUZPPFZMUPKLLV-UHFFFAOYSA-N 0.000 description 1
- 238000002156 mixing Methods 0.000 description 1
- 239000006174 pH buffer Substances 0.000 description 1
- 238000007789 sealing Methods 0.000 description 1
- 239000011734 sodium Substances 0.000 description 1
- JVBXVOWTABLYPX-UHFFFAOYSA-L sodium dithionite Chemical compound [Na+].[Na+].[O-]S(=O)S([O-])=O JVBXVOWTABLYPX-UHFFFAOYSA-L 0.000 description 1
- 239000003381 stabilizer Substances 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 238000000967 suction filtration Methods 0.000 description 1
- 229910052717 sulfur Inorganic materials 0.000 description 1
- 239000011593 sulfur Substances 0.000 description 1
- 238000001308 synthesis method Methods 0.000 description 1
- 238000012546 transfer Methods 0.000 description 1
- 238000005406 washing Methods 0.000 description 1
- 238000005303 weighing Methods 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C381/00—Compounds containing carbon and sulfur and having functional groups not covered by groups C07C301/00 - C07C337/00
- C07C381/14—Compounds containing a carbon atom having four bonds to hetero atoms with a double bond to one hetero atom and at least one bond to a sulfur atom further doubly-bound to oxygen atoms
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P20/00—Technologies relating to chemical industry
- Y02P20/141—Feedstock
Landscapes
- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
Abstract
The invention relates to a process for preparing thiourea dioxide by a carbon dioxide solvent method, which comprises the steps of adding dry ice or liquid carbon dioxide and a small amount of thiourea aqueous solution into a reaction kettle; under the stirring condition, when the temperature of the system is stabilized at 3-6 ℃, dropwise adding hydrogen peroxide with the mass concentration of 70-80% and the balance of thiourea aqueous solution, and controlling the pressure in the reaction kettle to be maintained at 3.7-4.0MPa in the dropwise adding process; aging for 5-15min after the dropwise addition, and drying to obtain the final product. The process takes carbon dioxide dissolved in water as a solvent, and is prepared by oxidizing thiourea with hydrogen peroxide, so that the reaction time is shortened, and the prepared thiourea dioxide has the advantages of high yield, good purity and the like.
Description
Technical Field
The invention belongs to the technical field of chemical synthesis, and particularly relates to a process for preparing thiourea dioxide by a carbon dioxide solvent method.
Background
Thiourea dioxide is a substitute product of sodium hydrosulfite, is an inorganic compound, and has the characteristics of strong reducibility, good thermal stability, convenient storage and transportation and the like. The product can be used as a reducing agent, a bleaching decolorizer, a plastic stabilizer, an organic synthetic antioxidant, an effect agent of a photosensitive material and the like; the method is widely applied to the industries of printing and dyeing, papermaking and the like.
At present, thiourea dioxide (hereinafter abbreviated as TD) generally has three types in the synthetic route: (1) a preparation method of taking ozone and thiourea as raw materials; (2) a preparation method which takes calcium cyanamide, ammonium sulfide and hydrogen peroxide as raw materials; (3) the synthesis method takes thiourea and hydrogen peroxide as raw materials and is carried out in the presence of a catalyst. The comparison shows that the third process route has the characteristics of easily obtained raw materials, simple preparation and easy industrial production. The reaction belongs to a strong exothermic reaction, and when the temperature of the system is too high, a side reaction can occur to generate sulfur, so that the product turns yellow, and therefore, the defects of high consumption, large heat exchange device, high construction and maintenance cost and the like are caused due to the fact that an ice machine is required for refrigeration and heat exchange in the reaction process. In addition, although the conventional methods for producing TD mainly include an aqueous solvent method, TD has a certain solubility in water, and thus the yield of TD is low.
The prior patent application CN112979520A of this company discloses a thiourea dioxide production process, which uses cetyl alcohol ester as a heat exchange medium to exchange heat, however, after a period of industrialization, it is gradually found that the crude separation of thiourea dioxide and cetyl alcohol ester is easier, 0.1-0.3% of cetyl alcohol ester in the finished product still remains in thiourea dioxide, and the purity of the finished thiourea dioxide is about 95%.
Disclosure of Invention
The invention aims to overcome the defects of the prior art and provides a process for preparing thiourea dioxide by a carbon dioxide solvent method.
In order to achieve the purpose, the invention adopts the following technical scheme:
a process for preparing thiourea dioxide by a carbon dioxide solvent method comprises the following steps:
1) adding dry ice or liquid carbon dioxide and a small amount of thiourea aqueous solution into a reaction kettle (the temperature is extremely low, and the temperature is raised by heat exchange through a heat exchanger);
2) under the stirring condition, when the temperature of the system is stabilized at 3-6 ℃, dropwise adding hydrogen peroxide with the mass concentration of 70-80% and the balance of thiourea aqueous solution, and controlling the pressure in the reaction kettle to be maintained at 3.7-4.0MPa in the dropwise adding process;
3) aging for 5-15min after the dropwise addition, and drying to obtain the final product.
In particular, thiourea and H 2 O 2 The optimum reaction molar ratio of (a) to (b) is 1: 2. Excessive thiourea at the early stage of the reaction; h is added when the reaction is finished along with the continuous addition of the hydrogen peroxide 2 O 2 Slight excess (i.e.H 2 O 2 The total addition amount is excessive relative to thiourea), thiourea and H are added in consideration of ineffective decomposition of hydrogen peroxide 2 O 2 May be 1: 2.2-2.5, preferably in a molar ratio of 1: 2.3.
specifically, the mass ratio of thiourea to dry ice is 1: 20-25. The mass of the required dry ice and liquid carbon dioxide can be determined according to the molar reaction heat of thiourea dioxide-536.15 KJ/mol-531.97 KJ/mol and the phase change heat of the dry ice in a reaction temperature range of 225.344 kJ/kg-214.25 kJ/kg. The theoretical mass ratio of thiourea to dry ice is 1: considering that dry ice is easily lost during the addition process, the ratio of the dry ice to the dry ice is 1: 25 by mass ratio.
Further, in the step 1) and the step 2), the mass concentration of the thiourea aqueous solution is 10-15%, and the adding amount of the thiourea aqueous solution in the step 1) is 8-12% of the total weight of the thiourea aqueous solution.
Specifically, in order to avoid excessive byproducts generated by too fast reaction heat release, the hydrogen peroxide and thiourea aqueous solution is dropwise added by a high-pressure pump, and mechanical stirring is started. In the step 2), the stirring speed is 100-.
Further, in the step 2), when the consumption of the raw material thiourea is 100g, the dropping speed of hydrogen peroxide is controlled to be 6-8 ml/min; the drop speed of the thiourea aqueous solution is controlled to be 40-45 ml/min. The invention selects hydrogen peroxide with the mass concentration of 70-80%, water is generated in the reaction process, and carbon dioxide takes away almost all water (carbon dioxide gas is continuously discharged in the reaction and continuously takes away water in the system, almost no water exists in the product at the end, almost no side reaction occurs, the yield is greatly improved, and the stability of the product is further improved).
The invention can control the pressure in the reaction kettle in the reaction process by installing a pressure change valve on the reaction kettle and setting the pressure value to be 3.7MPa to 4.0MPa (3 ℃ to 6 ℃). Quantitative dry ice is added, the phase change of the dry ice is gas and liquid, and the pressure of the system rises and absorbs heat during the phase change. When the pressure exceeds the pressure value of the pressure change valve, releasing carbon dioxide gas in the reaction kettle, and taking out water in the system when the carbon dioxide gas is released; meanwhile, hydrogen peroxide is dripped into the reaction kettle, the hydrogen peroxide thiourea oxide releases heat to raise the temperature, liquid carbon dioxide is vaporized again to absorb heat along with the rise of the temperature, the system pressure reaches a limit value again, the pressure change valve is opened again, and a certain amount of water is taken away when the carbon dioxide gas is released; the dropping of hydrogen peroxide raises the temperature and the pressure reaches the limit value of the pressure change valve again, so that the circulation is realized. Keeping the balance of the addition of carbon dioxide overflow and hydrogen peroxide. The carbon dioxide and water are separated, and the carbon dioxide can be recycled. During industrial production, part of liquid carbon dioxide can be added for bottoming, and then the rest of liquid carbon dioxide is introduced into the reaction kettle at a certain flow rate along with the reaction of hydrogen peroxide and thiourea, (the heat absorption capacity of the carbon dioxide is ensured to be matched with the heat release capacity of the reaction of the hydrogen peroxide and the thiourea and is larger than the heat release capacity of the reaction of the hydrogen peroxide and the thiourea, a pressure-resistant storage tank can be selected, and when the pressure of the liquid carbon dioxide is 3Mpa, the temperature is-5 ℃, and a pressure-resistant conveying pipe is adopted for conveying).
In the invention, the reaction temperature is preferably 3-6 ℃, the optimal pH value of the system is 3-6, and by-products are generated when the temperature and the pH value are too low or too high, thus influencing the purity of the product. Meanwhile, carbon dioxide exists in the system, and carbon dioxide dissolved in water generates carbonic acid, so that a corresponding weak acid environment can be provided just, and other pH buffers are not required to be additionally added.
The invention uses liquid carbon dioxide as solvent, which has five functions in the system: the first is inert solvent, the second is heat exchange medium, the third is water produced in the reaction of taking out the system, so that the yield is improved, the fourth is pH regulator, and the fifth is the gasification of carbon dioxide, which brings certain mixing effect to the reaction system.
Conventionally, the hexadecanol ester is used as a heat exchange medium to prepare the thiourea dioxide, and a small amount of the hexadecanol ester in a finished product is remained in the thiourea dioxide. Through further experiments and exploration by the technicians of the department, the carbon dioxide is found to be free from the problem, and the discovery is surprising: carbon dioxide as inert gas does not participate in the reaction, more importantly, the gas-liquid conversion is easy, the heat exchange efficiency is extremely high, and the conventional reaction time of 8 hours can be directly reduced to30 minutes (cetyl alcohol ester as heat exchange medium, reaction can only be shortened to 3 hours). The reason is that: firstly, carbon dioxide is as the heat transfer medium between the gas-liquid, and the gas flow rate is very fast, and the separation of carbon dioxide gas and water is also very easy, and carbon dioxide's gas compressor is also very ripe, compares in the equipment to liquid refrigeration, and efficiency is higher. And secondly, carbon dioxide can generate carbonic acid after being dissolved in water, so that a weak acidic environment is exactly provided for the reaction, and impurities and side effects brought by the pH regulator are reduced and replaced. CO with pH regulator after reaction 2 Can not remain in the product, and improves the stability of the product. Meanwhile, liquid carbon dioxide is used as a solvent, so that the use of water is reduced, and the product yield is further improved.
Compared with the prior art, the invention has the following beneficial effects:
1) the characteristic of carbon dioxide phase change heat absorption is adopted to remove a large amount of heat released in the TD synthesis reaction, so that uniform and rapid heat exchange is achieved, the system temperature is controlled, refrigeration equipment such as a coil or a jacket is not needed, and the production cost is reduced;
2) liquid carbon dioxide is used as a solvent, and deionized water is not required to be added as the solvent; 70-80% of hydrogen peroxide is used, so that the water content in the system is less, the thiourea dioxide loss is less, and the yield is higher; the carbon dioxide is inert gas, does not participate in the reaction and can be recycled; carbon dioxide is used as a heat exchange medium, so that the post-treatment is simple;
3) when carbon dioxide gas is released, water generated by the reaction of the system can be taken out, the loss of the conventional drying step is reduced, and the product yield is further improved. Carbon dioxide is dissolved in water to generate carbonic acid, an acidic environment is provided, and a pH regulator such as ammonium carbonate and the like does not need to be additionally added;
4) the reaction time is shortened: the reaction time is directly shortened to about 30-40min from the prior 8 hours.
Detailed Description
The technical solution of the present invention is further described in detail with reference to the following examples, but the scope of the present invention is not limited thereto.
In the following examples, all the raw materials are common products directly available in the art.
Example 1
A process for preparing thiourea dioxide by a carbon dioxide solvent method comprises the following steps:
1) 2.5 kg of dry ice and 100g of thiourea are taken and prepared into thiourea aqueous solution with the mass concentration of 12 percent. Dry ice and a small amount of thiourea aqueous solution with the mass concentration of 12% (the addition amount is 1/10 of the total weight of the thiourea aqueous solution) are added into a reaction kettle at one time;
2) under the stirring condition, the stirring speed is 400 r/min, when the temperature of the system is stabilized at about 4 ℃ (about 5 min), hydrogen peroxide with the mass concentration of 70% is dripped by a high-pressure pump 1, and the dripping speed is controlled at 7.4 ml/min; dropwise adding thiourea aqueous solution with the residual mass concentration of 12% into the high-pressure pump 2, and controlling the dropping speed at 40 ml/min; controlling the pressure in the reaction kettle to be maintained at 3.87MPa in the dripping process; the mass ratio of the thiourea to the dry ice is 1: 25; thiourea and H 2 O 2 In a molar ratio of 1: 2.3;
3) after 20min, dropwise adding, aging for 10min, and drying at 60 ℃ to obtain the thiourea dioxide product with 124.98g total and 88% yield, because the product has little water content and does not need suction filtration and centrifugation.
The purity of the thiourea dioxide product reaches 99.9 percent, the thermal stability can reach 200 minutes by being determined by referring to the standard HGT3258-2020 in the thiourea dioxide chemical industry, and the product is obviously improved by 50 minutes compared with the conventional high-stability thiourea dioxide. The thiourea dioxide content and the thermal stability can be specifically determined as follows.
Determination of thiourea dioxide content
1.1.1 method summary
In alkalescent solution, thiourea dioxide and thiourea react with iodine quantitatively, and residual iodine is back-dripped by sodium thiosulfate standard titration solution
And (3) subtracting the thiourea content from the total content to obtain the thiourea dioxide content.
1.1.2 reagents
Sulfuric acid solution: 1+ 8;
sodium bicarbonate solution: 10 g/L;
iodine standard titration solution:c（1/2I 2 ）≈0.l mol/L；
sodium thiosulfate standard titration solution:c（Na 2 S 2 O 3 ）≈0.l mol/L；
starch indicator: 10 g/L.
1.1.3 analytical procedures
Weighing 0.5 g of sample to be accurate to 0.0002 g, placing the sample in a 50 mL beaker, adding water to dissolve the sample, transferring the sample into a 250 mL volumetric flask, diluting the sample to a scale mark, and shaking up.
Transferring 15 mL of test solution into a 250 mL iodine measuring bottle by using a pipette, transferring 25 mL of iodine standard titration solution by using the pipette, quickly adding 50 mL of sodium bicarbonate solution, immediately covering a bottle stopper, sealing with water, placing in the dark for 10min, washing the bottle stopper by using water, adding 10 mL of sulfuric acid solution, titrating by using sodium thiosulfate standard titration solution until the solution is light yellow, adding 1 mL of starch indicator, continuously titrating until blue disappears to be colorless, and keeping l min as an end point.
A blank test was also performed, and the other operations and reagents added in the blank test were the same as those in the test solution except that no sample was added.
1.1.4 results calculation
The content of thiourea dioxide is calculated by mass fractionw 1 In% by weight, the value is calculated as follows:
in the formula:
V 0 -the value of the volume of the standard titration solution of sodium thiosulfate consumed for titrating the blank test solution, in milliliters (mL);
V 1 -the value of the volume of the standard titration solution of sodium thiosulfate consumed by titration of the test solution, in milliliters (mL);
c the exact value of the concentration of the standard titration solution of sodium thiosulfate in moles per liter (mol/L);
mnumber of the mass of the sampleValues in grams (g);
Mthiourea dioxide (CH) 4 N 2 O 2 S) in grams per mole (g/mol) (M = 108.12);
1.420-coefficient of thiourea to thiourea dioxide;
w 2 -mass fraction of thiourea determined in 6.5.
Taking the arithmetic mean value of the results of the parallel measurement as the measurement result, and the absolute difference value of the results of the two parallel measurements is not more than 0.20 percent.
Determination of thermal stability
1.2.1 method summary
The stability of the sample to heat was evaluated by placing the sample in a cuvette in a thermostatic water bath at 95 ℃. + -. 0.5 ℃ until the time at which the sample starts to decompose.
1.2.2 instruments, Equipment
And (3) constant-temperature water bath: the temperature control range is from room temperature to 100 ℃, and the temperature uniformity is less than or equal to 0.5 ℃;
a colorimetric tube: 50 mL;
standard thermometer: the division value is 0.5 ℃;
a glass funnel.
1.2.3 analytical procedures
The dried cuvette was placed in a thermostatic water bath, which was heated to 95 ℃. + -. 0.5 ℃ and kept constant. After the temperature of the cuvette stabilized at 95 ℃. + -. 0.5 ℃, 2.0 g of the sample was weighed to an accuracy of 0.1 g, the sample was placed into the cuvette through a glass funnel and the time was recordedt 1 Recording the time when the sample in the colorimetric tube begins to smoket 2 。
Note: the assay must be carried out in a fume hood, with the hood kept ventilated, and the hood glass window lowered.
1.2.4 results calculation
The thermal stability is expressed as t as the time from the start of heating of the sample to decomposition and is calculated as follows:
in the formula:
t 1 ——the time value of the sample in minutes (min) when put into the colorimetric cylinder;
t 2 ——the time at which the sample began to smoke was measured in minutes (min).
Taking the arithmetic mean value of the parallel measurement results as the measurement result, and the absolute difference value of the two parallel measurement results is not more than 3 min.
Claims (6)
1. A process for preparing thiourea dioxide by a carbon dioxide solvent method is characterized by comprising the following steps:
1) adding dry ice or liquid carbon dioxide and a small amount of thiourea aqueous solution into a reaction kettle;
2) under the stirring condition, when the temperature of the system is stabilized at 3-6 ℃, dropwise adding hydrogen peroxide with the mass concentration of 70-80% and the balance of thiourea aqueous solution, and controlling the pressure in the reaction kettle to be maintained at 3.7-4.0MPa in the dropwise adding process;
3) aging for 5-15min after the dropwise addition, and drying to obtain the final product.
2. The process for preparing thiourea dioxide according to claim 1, wherein thiourea and H are used as the solvent 2 O 2 In a molar ratio of 1: 2.2-2.5.
3. The process for preparing thiourea dioxide according to claim 1, wherein the mass ratio of thiourea and dry ice is 1: 20-25.
4. The process for preparing thiourea dioxide according to claim 1, wherein in the step 1) and the step 2), the mass concentration of the thiourea aqueous solution is 10-15%, and the addition amount of the thiourea aqueous solution in the step 1) is 8-12% of the total weight of the thiourea aqueous solution.
5. The process for preparing thiourea dioxide according to claim 1, wherein in the step 2), the stirring speed is 100-800 r/min.
6. The process for preparing thiourea dioxide by the carbon dioxide solvent method as claimed in claim 1, wherein in the step 2), when the dosage of the raw material thiourea is 100g, the dropping speed of hydrogen peroxide is controlled to be 6-8 ml/min; the drop speed of the thiourea aqueous solution is controlled to be 40-45 ml/min.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210403187 | 2022-04-18 | ||
| CN2022104031874 | 2022-04-18 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN114874117A true CN114874117A (en) | 2022-08-09 |
Family
ID=82671136
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202210420886.XA Pending CN114874117A (en) | 2022-04-18 | 2022-04-21 | Process for preparing thiourea dioxide by carbon dioxide solvent method |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN114874117A (en) |
Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4235812A (en) * | 1978-07-25 | 1980-11-25 | Tokai Denka Kogyo Kabushiki Kaisha | Process for preparing thiourea dioxide |
| JPH08183763A (en) * | 1994-12-28 | 1996-07-16 | Mitsubishi Gas Chem Co Inc | Production of aqueous solution of thiourea dioxide |
| CN1554645A (en) * | 2003-12-26 | 2004-12-15 | 南化集团研究院 | New process for synthesizing thiourea dioxide |
| CN109485591A (en) * | 2018-12-12 | 2019-03-19 | 濮阳宏业环保新材料股份有限公司 | A kind of buffering production technology of thiourea dioxide |
| CN209322759U (en) * | 2018-12-12 | 2019-08-30 | 濮阳宏业环保新材料股份有限公司 | A kind of thiourea dioxide production system of the operation of low energy consumption under the conditions of microthermal climate |
| CN112979520A (en) * | 2021-01-30 | 2021-06-18 | 濮阳宏业环保技术研究院有限公司 | Production process of thiourea dioxide |
-
2022
- 2022-04-21 CN CN202210420886.XA patent/CN114874117A/en active Pending
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4235812A (en) * | 1978-07-25 | 1980-11-25 | Tokai Denka Kogyo Kabushiki Kaisha | Process for preparing thiourea dioxide |
| JPH08183763A (en) * | 1994-12-28 | 1996-07-16 | Mitsubishi Gas Chem Co Inc | Production of aqueous solution of thiourea dioxide |
| CN1554645A (en) * | 2003-12-26 | 2004-12-15 | 南化集团研究院 | New process for synthesizing thiourea dioxide |
| CN109485591A (en) * | 2018-12-12 | 2019-03-19 | 濮阳宏业环保新材料股份有限公司 | A kind of buffering production technology of thiourea dioxide |
| CN209322759U (en) * | 2018-12-12 | 2019-08-30 | 濮阳宏业环保新材料股份有限公司 | A kind of thiourea dioxide production system of the operation of low energy consumption under the conditions of microthermal climate |
| CN112979520A (en) * | 2021-01-30 | 2021-06-18 | 濮阳宏业环保技术研究院有限公司 | Production process of thiourea dioxide |
Non-Patent Citations (2)
| Title |
|---|
| 泸州天然气化工尿素车间编: "《食品冷冻冷藏技术与设备》", 28 February 1978, 石油化学工业出版社, pages: 483 - 127 * |
| 陈均志等: "新型纸浆漂白剂――甲脒亚磺酸的制备", 《西北轻工业学院学报》, vol. 19, no. 1, pages 34 - 37 * |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN110372632B (en) | Fluorescent probe molecule for rapidly identifying hypochlorite ions and preparation method and application thereof | |
| CN115215306B (en) | Preparation method and preparation equipment of high-purity dichloro sulfonyl imide | |
| CN114874117A (en) | Process for preparing thiourea dioxide by carbon dioxide solvent method | |
| CN109485583A (en) | The preparation method of N, N '-diisopropylcarbodiimide | |
| CN112375006B (en) | Method for improving conversion rate in production of iminodisuccinate | |
| CA1332267C (en) | Process for producing cyanamide | |
| US5321156A (en) | Process for preparing alkali metal salts of 3-hydroxypropionic acid | |
| CN114988376A (en) | Method for producing lithium amide | |
| WO2023045601A1 (en) | Method for preparing tricine | |
| US4217294A (en) | Method for producing mercaptan-containing organosilicon compounds | |
| CN115569624B (en) | Continuous production equipment and production method of nitrogen-doped organic sulfur removal agent | |
| JP6180718B2 (en) | Method for producing lithium iodide aqueous solution and use thereof | |
| CA1067676A (en) | Manufacture of sodium dithionite | |
| CN111689506A (en) | Method for recovering magnesium chloride and tetrahydrofuran from Grignard reaction wastewater | |
| CN110343403A (en) | A kind of pyrazolines dyestuff and preparation method thereof identifying inferior sulfate radical | |
| CA1277678C (en) | Bechamp reduction of dns to das using h2so4 and trace of hoac | |
| CN112358497A (en) | Preparation method of polysulfide silane coupling agent with lighter color | |
| US5498400A (en) | Preparation of thionyl chloride and phosphorus oxyhloride from sulfur dioxide | |
| CN220071640U (en) | Device for continuously synthesizing alcohol alkali metal salt in three steps | |
| US5208002A (en) | Method of producing alkali metal azides | |
| US2404800A (en) | Process for the production of alkyl bromides | |
| CN117384099A (en) | Ratio colorimetric fluorescent probe and preparation method and application thereof | |
| CN109517020A (en) | The synthetic method of Delta-9,11- hydroxyl progesterone | |
| Nogare et al. | Acidimetric Determination of Vicinal Hydroxyl by Means of Sodium Periodate | |
| US4276273A (en) | Production of sodium polyphosphates |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| TA01 | Transfer of patent application right |
Effective date of registration: 20231102 Address after: 457400 East Road, 600m north of the intersection of national highway 106 and Minsheng Road, Nanle County, Puyang City, Henan Province Applicant after: Puyang Shengkai environmental protection new material technology Co.,Ltd. Address before: 457400 East Road, 600m north of the intersection of national highway 106 and Minsheng Road, Nanle County, Puyang City, Henan Province Applicant before: Puyang Shengkai environmental protection new material technology Co.,Ltd. Applicant before: Puyang Hongye Environmental Protection Technology Research Institute Co.,Ltd. |
|
| TA01 | Transfer of patent application right |