CN110589868A - Method for preparing high-purity sulfate and by-producing caprolactam from caprolactam sulfate - Google Patents
Method for preparing high-purity sulfate and by-producing caprolactam from caprolactam sulfate Download PDFInfo
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- CN110589868A CN110589868A CN201910832819.7A CN201910832819A CN110589868A CN 110589868 A CN110589868 A CN 110589868A CN 201910832819 A CN201910832819 A CN 201910832819A CN 110589868 A CN110589868 A CN 110589868A
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- caprolactam
- sulfate
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- filtrate
- purity
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- JBKVHLHDHHXQEQ-UHFFFAOYSA-N epsilon-caprolactam Chemical compound O=C1CCCCCN1 JBKVHLHDHHXQEQ-UHFFFAOYSA-N 0.000 title claims abstract description 186
- HIGZEFHDFAMPND-UHFFFAOYSA-N azepan-2-one;sulfuric acid Chemical compound OS(O)(=O)=O.O=C1CCCCCN1 HIGZEFHDFAMPND-UHFFFAOYSA-N 0.000 title claims abstract description 54
- 238000000034 method Methods 0.000 title claims abstract description 36
- QAOWNCQODCNURD-UHFFFAOYSA-L Sulfate Chemical compound [O-]S([O-])(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-L 0.000 title claims abstract description 33
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 123
- UHOVQNZJYSORNB-UHFFFAOYSA-N Benzene Chemical compound C1=CC=CC=C1 UHOVQNZJYSORNB-UHFFFAOYSA-N 0.000 claims abstract description 72
- 238000006243 chemical reaction Methods 0.000 claims abstract description 66
- 239000012071 phase Substances 0.000 claims abstract description 61
- 239000000706 filtrate Substances 0.000 claims abstract description 59
- 238000001914 filtration Methods 0.000 claims abstract description 40
- 238000000605 extraction Methods 0.000 claims abstract description 33
- 238000004064 recycling Methods 0.000 claims abstract description 32
- 238000005406 washing Methods 0.000 claims abstract description 31
- 239000012074 organic phase Substances 0.000 claims abstract description 30
- 239000000047 product Substances 0.000 claims abstract description 27
- OSGAYBCDTDRGGQ-UHFFFAOYSA-L calcium sulfate Chemical compound [Ca+2].[O-]S([O-])(=O)=O OSGAYBCDTDRGGQ-UHFFFAOYSA-L 0.000 claims abstract description 19
- 239000006227 byproduct Substances 0.000 claims abstract description 17
- 238000002156 mixing Methods 0.000 claims abstract description 17
- 239000000463 material Substances 0.000 claims abstract description 15
- 238000001704 evaporation Methods 0.000 claims abstract description 14
- 239000012065 filter cake Substances 0.000 claims abstract description 14
- 238000003756 stirring Methods 0.000 claims abstract description 14
- 239000003513 alkali Substances 0.000 claims abstract description 10
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 claims description 26
- QGZKDVFQNNGYKY-UHFFFAOYSA-N Ammonia Chemical compound N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 claims description 20
- 239000001103 potassium chloride Substances 0.000 claims description 15
- 239000000460 chlorine Substances 0.000 claims description 10
- ZAMOUSCENKQFHK-UHFFFAOYSA-N Chlorine atom Chemical compound [Cl] ZAMOUSCENKQFHK-UHFFFAOYSA-N 0.000 claims description 9
- 239000011575 calcium Substances 0.000 claims description 9
- 229910052801 chlorine Inorganic materials 0.000 claims description 9
- 150000001875 compounds Chemical class 0.000 claims description 9
- 239000003337 fertilizer Substances 0.000 claims description 9
- VTYYLEPIZMXCLO-UHFFFAOYSA-L Calcium carbonate Chemical compound [Ca+2].[O-]C([O-])=O VTYYLEPIZMXCLO-UHFFFAOYSA-L 0.000 claims description 7
- VEXZGXHMUGYJMC-UHFFFAOYSA-M Chloride anion Chemical compound [Cl-] VEXZGXHMUGYJMC-UHFFFAOYSA-M 0.000 claims description 7
- 239000002585 base Substances 0.000 claims description 5
- BWHMMNNQKKPAPP-UHFFFAOYSA-L potassium carbonate Substances [K+].[K+].[O-]C([O-])=O BWHMMNNQKKPAPP-UHFFFAOYSA-L 0.000 claims description 5
- BVKZGUZCCUSVTD-UHFFFAOYSA-L Carbonate Chemical compound [O-]C([O-])=O BVKZGUZCCUSVTD-UHFFFAOYSA-L 0.000 claims description 4
- 229910000019 calcium carbonate Inorganic materials 0.000 claims description 4
- 229910000027 potassium carbonate Inorganic materials 0.000 claims description 4
- 239000002994 raw material Substances 0.000 claims description 3
- 239000001110 calcium chloride Substances 0.000 claims description 2
- 229910001628 calcium chloride Inorganic materials 0.000 claims description 2
- 238000002360 preparation method Methods 0.000 claims description 2
- 230000035484 reaction time Effects 0.000 claims description 2
- 230000008901 benefit Effects 0.000 abstract description 6
- 229910052939 potassium sulfate Inorganic materials 0.000 description 39
- WCUXLLCKKVVCTQ-UHFFFAOYSA-M Potassium chloride Chemical group [Cl-].[K+] WCUXLLCKKVVCTQ-UHFFFAOYSA-M 0.000 description 28
- 229910052925 anhydrite Inorganic materials 0.000 description 22
- 239000000243 solution Substances 0.000 description 19
- OTYBMLCTZGSZBG-UHFFFAOYSA-L potassium sulfate Chemical compound [K+].[K+].[O-]S([O-])(=O)=O OTYBMLCTZGSZBG-UHFFFAOYSA-L 0.000 description 18
- 235000011164 potassium chloride Nutrition 0.000 description 14
- 238000001035 drying Methods 0.000 description 13
- 238000005303 weighing Methods 0.000 description 11
- 235000011151 potassium sulphates Nutrition 0.000 description 8
- 229910021529 ammonia Inorganic materials 0.000 description 7
- BFNBIHQBYMNNAN-UHFFFAOYSA-N ammonium sulfate Chemical compound N.N.OS(O)(=O)=O BFNBIHQBYMNNAN-UHFFFAOYSA-N 0.000 description 7
- 229910052921 ammonium sulfate Inorganic materials 0.000 description 7
- 235000011130 ammonium sulphate Nutrition 0.000 description 7
- 239000000203 mixture Substances 0.000 description 7
- NLXLAEXVIDQMFP-UHFFFAOYSA-N Ammonia chloride Chemical compound [NH4+].[Cl-] NLXLAEXVIDQMFP-UHFFFAOYSA-N 0.000 description 6
- 239000011259 mixed solution Substances 0.000 description 6
- 229910021653 sulphate ion Inorganic materials 0.000 description 5
- 125000003182 D-alloisoleucine group Chemical group [H]N([H])[C@@]([H])(C(=O)[*])[C@](C([H])([H])[H])([H])C(C([H])([H])[H])([H])[H] 0.000 description 4
- 239000001117 sulphuric acid Substances 0.000 description 4
- 235000011149 sulphuric acid Nutrition 0.000 description 4
- 229920002292 Nylon 6 Polymers 0.000 description 3
- 235000019270 ammonium chloride Nutrition 0.000 description 3
- 229910000069 nitrogen hydride Inorganic materials 0.000 description 3
- 238000000926 separation method Methods 0.000 description 3
- 238000006237 Beckmann rearrangement reaction Methods 0.000 description 2
- XDTMQSROBMDMFD-UHFFFAOYSA-N Cyclohexane Chemical compound C1CCCCC1 XDTMQSROBMDMFD-UHFFFAOYSA-N 0.000 description 2
- 239000004952 Polyamide Substances 0.000 description 2
- PVNJLUVGTFULAE-UHFFFAOYSA-N [NH4+].[Cl-].[K] Chemical compound [NH4+].[Cl-].[K] PVNJLUVGTFULAE-UHFFFAOYSA-N 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 238000005265 energy consumption Methods 0.000 description 2
- 230000007613 environmental effect Effects 0.000 description 2
- 238000004880 explosion Methods 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- 229920002647 polyamide Polymers 0.000 description 2
- 239000000126 substance Substances 0.000 description 2
- HIFJUMGIHIZEPX-UHFFFAOYSA-N sulfuric acid;sulfur trioxide Chemical compound O=S(=O)=O.OS(O)(=O)=O HIFJUMGIHIZEPX-UHFFFAOYSA-N 0.000 description 2
- 229910003556 H2 SO4 Inorganic materials 0.000 description 1
- 230000002378 acidificating effect Effects 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- AXCZMVOFGPJBDE-UHFFFAOYSA-L calcium dihydroxide Chemical compound [OH-].[OH-].[Ca+2] AXCZMVOFGPJBDE-UHFFFAOYSA-L 0.000 description 1
- 239000000920 calcium hydroxide Substances 0.000 description 1
- 229910001861 calcium hydroxide Inorganic materials 0.000 description 1
- 239000003054 catalyst Substances 0.000 description 1
- 239000013078 crystal Substances 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000004090 dissolution Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 229920006351 engineering plastic Polymers 0.000 description 1
- 230000002349 favourable effect Effects 0.000 description 1
- XLYOFNOQVPJJNP-ZSJDYOACSA-N heavy water Substances [2H]O[2H] XLYOFNOQVPJJNP-ZSJDYOACSA-N 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 230000003472 neutralizing effect Effects 0.000 description 1
- 239000000618 nitrogen fertilizer Substances 0.000 description 1
- 229920001778 nylon Polymers 0.000 description 1
- 229920006255 plastic film Polymers 0.000 description 1
- 239000002985 plastic film Substances 0.000 description 1
- 238000006116 polymerization reaction Methods 0.000 description 1
- 239000000843 powder Substances 0.000 description 1
- 230000036632 reaction speed Effects 0.000 description 1
- 239000002689 soil Substances 0.000 description 1
- 239000002904 solvent Substances 0.000 description 1
- 239000007858 starting material Substances 0.000 description 1
- 239000002699 waste material Substances 0.000 description 1
- 239000002351 wastewater Substances 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01D—COMPOUNDS OF ALKALI METALS, i.e. LITHIUM, SODIUM, POTASSIUM, RUBIDIUM, CAESIUM, OR FRANCIUM
- C01D5/00—Sulfates or sulfites of sodium, potassium or alkali metals in general
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01F—COMPOUNDS OF THE METALS BERYLLIUM, MAGNESIUM, ALUMINIUM, CALCIUM, STRONTIUM, BARIUM, RADIUM, THORIUM, OR OF THE RARE-EARTH METALS
- C01F11/00—Compounds of calcium, strontium, or barium
- C01F11/46—Sulfates
-
- C—CHEMISTRY; METALLURGY
- C05—FERTILISERS; MANUFACTURE THEREOF
- C05C—NITROGENOUS FERTILISERS
- C05C3/00—Fertilisers containing other salts of ammonia or ammonia itself, e.g. gas liquor
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07D—HETEROCYCLIC COMPOUNDS
- C07D201/00—Preparation, separation, purification or stabilisation of unsubstituted lactams
- C07D201/02—Preparation of lactams
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07D—HETEROCYCLIC COMPOUNDS
- C07D223/00—Heterocyclic compounds containing seven-membered rings having one nitrogen atom as the only ring hetero atom
- C07D223/02—Heterocyclic compounds containing seven-membered rings having one nitrogen atom as the only ring hetero atom not condensed with other rings
- C07D223/06—Heterocyclic compounds containing seven-membered rings having one nitrogen atom as the only ring hetero atom not condensed with other rings with hetero atoms or with carbon atoms having three bonds to hetero atoms with at the most one bond to halogen, e.g. ester or nitrile radicals, directly attached to ring carbon atoms
- C07D223/08—Oxygen atoms
- C07D223/10—Oxygen atoms attached in position 2
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
- C01P2006/00—Physical properties of inorganic compounds
- C01P2006/80—Compositional purity
Landscapes
- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Inorganic Chemistry (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Life Sciences & Earth Sciences (AREA)
- Geology (AREA)
- Fertilizers (AREA)
Abstract
The invention discloses a method for preparing high-purity sulfate and by-producing caprolactam by caprolactam sulfate, which comprises the steps of calculating the amount of caprolactam sulfate and alkali according to the stoichiometric number of caprolactam sulfate and alkali, respectively adding water for dissolving and size mixing, and putting into a reaction tank for reaction; filtering the material, and washing a filter cake with water to obtain a filtrate I; adjusting the pH value of the washed filter residue to 6.0-7.0 to obtain sulfate, filtering the sulfate and washing the sulfate with water to obtain high-purity sulfate and filtrate II; adding benzene into the filtrate I for extraction, stirring, standing for layering, and separating to obtain an organic phase and a water phase; and adding water into the organic phase for back extraction to obtain a water phase, evaporating the obtained water phase to dryness to obtain a caprolactam product, and purifying the oil phase for recycling. The invention realizes the purpose of producing high-purity calcium sulfate and by-product caprolactam with high value, and realizes the recycling of resources and the maximization of economic benefit.
Description
Technical Field
The invention relates to a method for preparing high-purity sulfate and by-producing caprolactam by using caprolactam sulfate, in particular to a process for producing high-purity calcium sulfate and by-producing caprolactam by using the caprolactam sulfate after Beckmann rearrangement in the process of preparing caprolactam by a cyclohexane method.
Background
Caprolactam formula C6H11NO, white powder or crystal in appearance, oily hand feeling. Caprolactam is one of important organic chemical raw materials, and is mainly used for generating polyamide slices (usually called nylon-6 slices or nylon-6 slices) through polymerization and further processing the polyamide slices into nylon fibers, engineering plastics and plastic films. The nylon-6 slice has different application fields depending on the quality and indexes.
In the process of producing caprolactam by using benzene and cyclohexane, a certain amount of fuming sulfuric acid is required to be added as a catalyst after Beckmann rearrangement, and ammonium sulfate is a byproduct. The byproduct ammonium sulfate is high-price liquid ammonia and fuming sulfuric acid which are converted into low-value ammonium sulfate, so that the higher the byproduct ammonium sulfate is, the higher the cost of caprolactam is. Moreover, ammonium sulfate, which is an inefficient and acidic nitrogenous fertilizer, is not favorable to soil and has been not favored by agriculture, has a problem of difficulty in marketing due to its excessively high by-product ammonium sulfate.
In the original process, ammonia is used for neutralizing caprolactam sulfate, so that the gas-liquid reaction speed is high, heat is released, the reaction progress is difficult to control, and certain safety risk exists. The device has the serious safety risk and environmental risk such as ammonia leakage, ammonia explosion, and in addition, the safety risk is not negligible as the serious hazard source of ammonia.
Disclosure of Invention
In view of the defects of the prior art, the invention provides a method for preparing high-purity sulfate and by-producing caprolactam by caprolactam sulfate, which comprises the steps of preparing high-purity calcium sulfate and by-producing caprolactam by reacting caprolactam sulfate with alkali, realizing the purpose of producing high-purity calcium sulfate and by-producing a high-value caprolactam product, and realizing the recycling of resources and the maximization of economic benefit.
The invention adopts the following technical scheme:
a method for preparing high-purity sulfate and byproduct caprolactam from caprolactam sulfate, which comprises the following steps:
A. calculating the amount of caprolactam sulfate and alkali according to the stoichiometric number of the caprolactam sulfate and the alkali, respectively adding water for dissolving and size mixing, and then putting into a reaction tank for reaction;
B. filtering the material prepared in the step A, and washing a filter cake with water to obtain a filtrate I; adjusting the pH value of the washed filter residue to 6.0-7.0 to obtain sulfate, filtering the sulfate and washing the sulfate with water to obtain high-purity sulfate and filtrate II;
C. adding benzene into the filtrate I obtained in the step B for extraction, stirring, standing for layering, and separating to obtain an organic phase and a water phase;
D. adding water into the organic phase obtained in the step C for back extraction to obtain a water phase, evaporating the obtained water phase to obtain a caprolactam product, and purifying the oil phase for recycling;
the preparation of the high-purity calcium sulfate and the byproduct caprolactam are finished by using the caprolactam sulfate.
Preferably, the mass fraction of caprolactam in the caprolactam sulfate in the step A is 40-50%, and the mass fraction of sulfuric acid is 50-60%. The sulfuric acid content is in a range that ensures that the reaction proceeds efficiently, which is also a component range of caprolactam sulfate produced in the caprolactam production process.
Preferably, the water addition amount in the step A is 1.2 to 1.8 times of the total mass of caprolactam sulfate and alkali. Too little water, incomplete dissolution of materials, influence of subsequent reaction efficiency, too much water, and increase of energy consumption in subsequent filtering and drying processes.
Preferably, the reaction temperature in the step A is 30-95 ℃, and the reaction time is 10-35 minutes.
Preferably, the filtrate II in the step B and the water phase obtained in the step C are returned to the reaction tank in the step A for recycling. The water phase is returned for recycling, so that the atom economic effect can be increased, and the economic benefit is increased.
Preferably, the filtration temperature in step B is 30-60 ℃.
Preferably, the volume ratio of the filtrate I in the step C is (4-6): 1 benzene was added for extraction. The benzene consumption is in certain range, can guarantee the extraction efficiency, saves the benzene consumption simultaneously, reduction in production cost.
Preferably, in the step D, 0.3-0.6 times of water is added into the organic phase obtained in the step C for back extraction. Too little water affects the efficiency of stripping caprolactam, and too much water increases the energy consumption in the subsequent drying process.
Even more preferably, the base in step A can be alkaline oxide or chloride or alkaline carbonate or a combination thereof, the base is KOH or Ca (OH)2The basic oxide is CaO or K2O, chloride is KCl or CaCl2The basic carbonate is K2CO3Or CaCO3。
The main reaction equations of the method are respectively as follows:
C6H11NO-HSO3 + Ca(OH)2 = CaSO4↓+ 2H2O+C6H11NO；
C6H11NO-HSO3 + CaO = CaSO4↓+ H2O+C6H11NO；
C6H11NO-HSO3 + CaCO3 = CaSO4↓+ H2O+ CO2↑+C6H11NO；
H2 SO4 +K2CO3 = K2SO4+ H2O+ CO2↑；
H2SO4 + KOH= K2SO4+ H2O；
caprolactam sulphate with Ca (OH)2CaO, or CaCO3Reaction to produce CaSO4Only caprolactam and CaSO in the reacted mixture4And CaSO at 20 ℃ according to the solubility curve4The solubility of (g/100 g of solvent) was only 0.26g, whereas the solubility of caprolactam was 456 g. They can therefore be separated by their solubility differences in water, and caprolactam also has a high solubility in benzene, while CaSO4Very low solubility in benzene, CaSO4And separation of caprolactam.
Still more preferably, when the base in step a is chloride: and B, maintaining the pH value of the reaction in the reaction tank in the step A to be 5.0-6.5 by introducing ammonia gas, concentrating and crystallizing the water phase obtained in the step C, filtering, returning the filtrate obtained after filtering to the reaction tank in the step A for recycling, and using the filter residue for producing the chlorine-based compound fertilizer.
The main reaction equations of the method are respectively as follows:
H2SO4 + 4KCl+2NH3 = K2SO4+ 2NH4Cl·KCl；
caprolactam sulfate with KCl and NH in sequence3The reaction produces potassium sulfate, and the mixture after the reaction contains caprolactam, potassium sulfate and potassium ammonium chloride, and according to the solubility curve, the solubility of the potassium sulfate is only 11.1g, the solubility of the ammonium chloride is 37.2g, the solubility of the potassium chloride is 34.2g, and the solubility of the caprolactam is 456g at 20 ℃. So that can pass them through waterThe solubility difference of the caprolactam in benzene is used for separation, in addition, the solubility of the caprolactam in the benzene is also large, and the solubility of the potassium sulfate, the ammonium chloride and the potassium chloride in the benzene is small, so that the separation of the potassium sulfate, the ammonium chloride and the caprolactam can be realized.
The invention has the following beneficial effects:
1. the invention has simple process, high product quality, sulfate content of more than or equal to 99 percent, high market price and good economic benefit. The purity of the byproduct caprolactam product is as high as 99.9 percent, and the economic benefit is obvious. Is convenient for industrial application, and has the advantages of cheap raw materials, low cost, no pollution and no wastewater.
2. The invention has mild reaction and easily controlled reaction progress. Can avoid the major safety risks and environmental risks of ammonia leakage, ammonia explosion and the like,
3. the invention adopts a safe, efficient and environment-friendly substance to replace the reaction of ammonia and caprolactam sulfate, thereby not only avoiding the generation of ammonium sulfate to cause economic loss, but also avoiding the safety and environment-friendly risks.
4. The obtained ammonium potassium chloride can be used for producing chlorine-based compound fertilizer, and no waste is generated.
Drawings
FIG. 1 is a process flow diagram of the present invention;
FIG. 2 is a flow diagram of the process of the present invention in which the starting material is chloride.
Detailed Description
The present invention will be described in further detail with reference to specific examples, but the embodiments of the present invention are not limited to the scope of the examples. These examples are intended to illustrate the invention only and are not intended to limit the scope of the invention.
Example 1
A method for preparing high-purity sulfate and byproduct caprolactam from caprolactam sulfate comprises the following steps:
1) caprolactam sulphate (w caprolactam =45%, w sulphuric acid = 55%) and Ca (OH)2Weighing according to the mass ratio of 2.4:1, adding 1.5 times of water by mass to dissolve caprolactam sulfate, adding 1.5 times of water by mass to Ca (OH)2Carrying out size mixing; then uniformly mixing the obtained solution, putting the mixed solution into a reaction tank, and reacting for 30 minutes at 80 ℃;
2) filtering the obtained material at 40 ℃, and washing the filter cake with water at the temperature of more than 70 ℃ to obtain filtrate I. Adding Ca (OH) into the washed filter residue2Solutions or H2SO4Adjusting the pH to 7.0 to obtain CaSO4，CaSO4Filtering and washing to obtain high-purity CaSO4And filtrate II, and returning the filtrate II to the reaction tank in the step 1) for recycling. CaSO4After drying, the purity is 97.6%.
3) And adding benzene into the filtrate I obtained in the step 2 according to the volume ratio of 5:1 for extraction, fully stirring, standing for layering, and separating to obtain an organic phase and a water phase.
4) Adding 0.5 time of water into the organic phase obtained in the step 3) for back extraction to obtain a water phase, and evaporating the obtained water phase to dryness to obtain a caprolactam product, wherein the purity of the caprolactam product is 99.5 percent, and the yield of the caprolactam is 98.7 percent. And (4) returning the water phase obtained in the step (3) to the reaction tank in the step (1) for recycling.
Example 2
A method for preparing high-purity sulfate and byproduct caprolactam from caprolactam sulfate comprises the following steps:
1) caprolactam sulphate (w caprolactam =45%, w sulphuric acid = 55%) and Ca (OH)2Weighing according to the mass ratio of 2.4:1, adding 1.5 times of water by mass to dissolve caprolactam sulfate, adding 1.5 times of water by mass to Ca (OH)2Carrying out size mixing; then uniformly mixing the obtained solution, putting the mixture into a reaction tank, and reacting for 30 minutes at 85 ℃;
2) filtering the obtained material at 60 ℃, and washing the filter cake with water at the temperature of more than 70 ℃ to obtain filtrate I. Adding Ca (OH) into the washed filter residue2Solutions or H2SO4Adjusting the pH to 7.0 to obtain CaSO4，CaSO4Filtering and washing to obtain high-purity CaSO4And (4) returning the filtrate II to the reaction tank in the step (1) for recycling. CaSO4After drying, the purity is 96.8%.
3) And adding benzene into the filtrate I obtained in the step 2 according to the volume ratio of 5:1 for extraction, fully stirring, standing for layering, and separating to obtain an organic phase and a water phase.
4) Adding 0.5 time of water into the organic phase obtained in the step 3) for back extraction to obtain a water phase, and evaporating the obtained water phase to dryness to obtain a caprolactam product, wherein the purity of the caprolactam product is 99.8 percent, and the yield of the caprolactam is 98.5 percent. And (4) returning the water phase obtained in the step (3) to the reaction tank in the step (1) for recycling.
Example 3
A method for preparing high-purity sulfate and byproduct caprolactam from caprolactam sulfate comprises the following steps:
1) caprolactam sulphate (w caprolactam =45%, w sulphuric acid = 55%) and Ca (OH)2Weighing according to the mass ratio of 2.4:1, adding 1.5 times of water by mass to dissolve caprolactam sulfate, adding 1.5 times of water by mass to Ca (OH)2Carrying out size mixing; then uniformly mixing the obtained solution, putting the mixed solution into a reaction tank, and reacting for 30 minutes at 90 ℃;
2) filtering the obtained material at 50 ℃, and washing the filter cake with water at the temperature of more than 70 ℃ to obtain filtrate I. Adding Ca (OH) into the washed filter residue2Solutions or H2SO4Adjusting the pH to 7.0 to obtain CaSO4，CaSO4Filtering and washing to obtain high-purity CaSO4And (4) returning the filtrate II to the reaction tank in the step (1) for recycling. CaSO4After drying, the purity is 97.2%.
3) And adding benzene into the filtrate I obtained in the step 2 according to the volume ratio of 5:1 for extraction, fully stirring, standing for layering, and separating to obtain an organic phase and a water phase.
4) Adding 0.5 time of water into the organic phase obtained in the step 3) for back extraction to obtain a water phase, and evaporating the obtained water phase to dryness to obtain a caprolactam product, wherein the purity of the caprolactam product is 99.7 percent, and the yield of the caprolactam is 98.3 percent. And (4) returning the water phase obtained in the step (3) to the reaction tank in the step (1) for recycling.
Example 4
A method for preparing high-purity sulfate and byproduct caprolactam from caprolactam sulfate comprises the following steps:
1) weighing caprolactam sulfate (w caprolactam =45%, w sulfuric acid = 55%) and CaO according to the mass ratio of 3.18:1, adding 1.5 times of water by mass to dissolve the caprolactam sulfate, and adding 1.5 times of water by mass to size the CaO; then uniformly mixing the obtained solution, putting the mixed solution into a reaction tank, and reacting for 30 minutes at 90 ℃;
2) and concentrating and crystallizing the obtained material, filtering at 55 ℃, and washing the filter cake with water at the temperature of more than 70 ℃ to obtain filtrate I. Adding CaO solution or H into the washed filter residue2SO4Adjusting the pH to 7.0 to obtain CaSO4，CaSO4Filtering and washing to obtain high-purity CaSO4And (4) returning the filtrate II to the reaction tank in the step (1) for recycling. CaSO4After drying, the purity is 97.2%.
3) And adding benzene into the filtrate I obtained in the step 2 according to the volume ratio of 5:1 for extraction, fully stirring, standing for layering, and separating to obtain an organic phase and a water phase.
4) Adding 0.5 time of water into the organic phase obtained in the step 3) for back extraction to obtain a water phase, and evaporating the obtained water phase to dryness to obtain a caprolactam product, wherein the purity of the caprolactam product is 99.7 percent, and the yield of the caprolactam is 98.5 percent. And (4) returning the water phase obtained in the step (3) to the reaction tank in the step (1) for recycling.
Example 5
A method for preparing high-purity sulfate and byproduct caprolactam from caprolactam sulfate comprises the following steps:
1) weighing caprolactam sulfate (w caprolactam =45%, w sulfuric acid = 55%) and KOH according to the mass ratio of 1.6:1, adding 1.5 times of water by mass to dissolve the caprolactam sulfate, and adding 1.5 times of water by mass to dissolve the KOH; then uniformly mixing the obtained solution, putting the mixture into a reaction tank, and reacting for 20 minutes at 60 ℃;
2) and concentrating and crystallizing the obtained material, filtering at 40 ℃, and washing the filter cake with water to obtain filtrate I. Adding KOH solution or H into the washed filter residue2SO4Adjusting the pH to 7.0 to obtain K2SO4，K2SO4Filtering and washing to obtain high-purity K2SO4And filtrate II, and returning the filtrate II to the reaction tank in the step 1) for recycling. K2SO4After drying, the purity is 99.2%.
3) And adding benzene into the filtrate I obtained in the step 2 according to the volume ratio of 5:1 for extraction, fully stirring, standing for layering, and separating to obtain an organic phase and a water phase.
4) Adding 0.5 time of water into the organic phase obtained in the step 3) for back extraction to obtain a water phase, and evaporating the obtained water phase to dryness to obtain a caprolactam product, wherein the purity of the caprolactam product is 99.1 percent, and the yield of the caprolactam is 98.6 percent. And (4) returning the water phase obtained in the step (3) to the reaction tank in the step (1) for recycling.
Example 6
A method for preparing high-purity sulfate and byproduct caprolactam from caprolactam sulfate comprises the following steps:
1) weighing caprolactam sulfate (w caprolactam =45%, w sulfuric acid = 55%) and KOH according to the mass ratio of 1.6:1, adding 1.5 times of water by mass to dissolve the caprolactam sulfate, and adding 1.5 times of water by mass to dissolve the KOH; then uniformly mixing the obtained solution, putting the mixture into a reaction tank, and reacting for 20 minutes at 50 ℃;
2) and concentrating and crystallizing the obtained material, filtering at 55 ℃, and washing a filter cake with water to obtain a filtrate I. Adding KOH solution or H into the washed filter residue2SO4Adjusting the pH to 7.0 to obtain K2SO4，K2SO4Filtering and washing to obtain high-purity K2SO4And filtrate II, and returning the filtrate II to the reaction tank in the step 1) for recycling. K2SO4After drying, the purity is 99.5%.
3) And adding benzene into the filtrate I obtained in the step 2 according to the volume ratio of 5:1 for extraction, fully stirring, standing for layering, and separating to obtain an organic phase and a water phase.
4) Adding 0.5 time of water into the organic phase obtained in the step 3) for back extraction to obtain a water phase, and evaporating the obtained water phase to dryness to obtain a caprolactam product, wherein the purity of the caprolactam product is 99.3 percent, and the yield of the caprolactam is 98.9 percent. And (4) returning the water phase obtained in the step (3) to the reaction tank in the step (1) for recycling.
Example 7
A method for preparing high-purity sulfate and byproduct caprolactam from caprolactam sulfate comprises the following steps:
1) weighing caprolactam sulfate (w caprolactam =45%, w sulfuric acid = 55%) and KOH according to the mass ratio of 1.6:1, adding 1.5 times of water by mass to dissolve the caprolactam sulfate, and adding 1.5 times of water by mass to dissolve the KOH; then uniformly mixing the obtained solution, putting the mixture into a reaction tank, and reacting for 20 minutes at 70 ℃;
2) and concentrating and crystallizing the obtained material, filtering at 35 ℃, and washing a filter cake with water to obtain a filtrate I. Adding KOH solution or H into the washed filter residue2SO4Adjusting the pH to 6.5 to obtain K2SO4，K2SO4Filtering and washing to obtain high-purity K2SO4And filtrate II, and returning the filtrate II to the reaction tank in the step 1) for recycling. K2SO4After drying, the purity is 99.5%.
3) And adding benzene into the filtrate I obtained in the step 2 according to the volume ratio of 5:1 for extraction, fully stirring, standing for layering, and separating to obtain an organic phase and a water phase.
4) Adding 0.5 time of water into the organic phase obtained in the step 3) for back extraction to obtain a water phase, and evaporating the obtained water phase to dryness to obtain a caprolactam product with the purity of 99.2 percent. And (4) returning the water phase obtained in the step (3) to the reaction tank in the step (1) for recycling.
Example 8
A method for preparing high-purity sulfate and byproduct caprolactam from caprolactam sulfate comprises the following steps:
1) caprolactam sulphate (w caprolactam =45%, w sulphuric acid = 55%) and K2CO3Weighing according to the mass ratio of 1.3:1, adding 1.5 times of water by mass to dissolve caprolactam sulfate, and adding 1.5 times of water by mass to dissolve KOH; then uniformly mixing the obtained solution, putting the mixture into a reaction tank, and reacting for 20 minutes at 60 ℃;
2) and concentrating and crystallizing the obtained material, filtering at 50 ℃, and washing a filter cake with water to obtain a filtrate I. Adding KOH solution or H into the washed filter residue2SO4Adjusting the pH to 6.5 to obtain K2SO4，K2SO4Filtering and washing to obtain high-purity K2SO4And filtrate II, and returning the filtrate II to the reaction tank in the step 1) for recycling. K2SO4After drying, the purity is 99.6%.
3) And adding benzene into the filtrate I obtained in the step 2 according to the volume ratio of 5:1 for extraction, fully stirring, standing for layering, and separating to obtain an organic phase and a water phase.
4) Adding 0.5 time of water into the organic phase obtained in the step 3) for back extraction to obtain a water phase, and evaporating the obtained water phase to dryness to obtain a caprolactam product, wherein the purity of the caprolactam product is 99.5 percent, and the yield of the caprolactam is 98.8 percent. And (4) returning the water phase obtained in the step (3) to the reaction tank in the step (1) for recycling.
Example 9
Caprolactam sulfate, KCl and NH3The method for preparing high-purity potassium sulfate, chlorine-based compound fertilizer and caprolactam by reaction comprises the following specific steps:
1) weighing caprolactam sulfate (w caprolactam =45%, w sulfuric acid = 55%) and KCl according to the mass ratio of 1:1.67, adding 1.5 times of water by mass to dissolve the caprolactam sulfate, and adding 1.5 times of water by mass to dissolve the KCl; then uniformly mixing the obtained solution, putting the mixed solution into a reaction tank, introducing ammonia gas into a reaction kettle, maintaining the pH value at 5.0-6.5, and reacting for 20 minutes at 40 ℃;
2) and concentrating and crystallizing the obtained material, filtering at 55 ℃, and washing a filter cake with water to obtain a filtrate I. The filter residue after washing is K2SO4，K2SO4Filtering and washing to obtain high-purity K2SO4And filtrate II, and returning the filtrate II to the reaction tank in the step 1) for recycling. K2SO4After drying, the purity is 98.9%.
3) And adding benzene into the filtrate I obtained in the step 2 according to the volume ratio of 5:1 for extraction, fully stirring, standing for layering, and separating to obtain an organic phase and a water phase.
4) Adding 0.5 time of water into the organic phase obtained in the step 3) for back extraction to obtain a water phase, and evaporating the obtained water phase to dryness to obtain a caprolactam product, wherein the purity of the caprolactam product is 99.1 percent, and the yield of the caprolactam is 99.4 percent.
5) And 3) concentrating and crystallizing the water phase obtained in the step 3), filtering, returning filtrate obtained after filtering to the reaction tank in the step 1 for recycling, and using filter residues for producing the chlorine-based compound fertilizer.
Example 10
Caprolactam sulfate, KCl and NH3The method for preparing high-purity potassium sulfate, chlorine-based compound fertilizer and caprolactam by reaction comprises the following specific steps:
1) weighing caprolactam sulfate (w caprolactam =45%, w sulfuric acid = 55%) and KCl according to the mass ratio of 1:1.67, adding 1.5 times of water by mass to dissolve the caprolactam sulfate, and adding 1.5 times of water by mass to dissolve the KCl; then uniformly mixing the obtained solution, putting the mixed solution into a reaction tank, introducing ammonia gas into a reaction kettle, maintaining the pH value at 5.0-6.5, and reacting for 20 minutes at 50 ℃;
2) and concentrating and crystallizing the obtained material, filtering at 50 ℃, and washing a filter cake with water to obtain a filtrate I. The filter residue after washing is K2SO4，K2SO4Filtering and washing to obtain high-purity K2SO4And filtrate II, and returning the filtrate II to the reaction tank in the step 1) for recycling. K2SO4After drying, the purity is 99.3%.
3) And adding benzene into the filtrate I obtained in the step 2 according to the volume ratio of 5:1 for extraction, fully stirring, standing for layering, and separating to obtain an organic phase and a water phase.
4) Adding 0.5 time of water into the organic phase obtained in the step 3) for back extraction to obtain a water phase, and evaporating the obtained water phase to dryness to obtain a caprolactam product, wherein the purity of the caprolactam product is 99.5 percent, and the yield of the caprolactam is 98.9 percent.
5) And 3) concentrating and crystallizing the water phase obtained in the step 3), filtering, returning filtrate obtained after filtering to the reaction tank in the step 1 for recycling, and using filter residues for producing the chlorine-based compound fertilizer.
Example 11
Caprolactam sulfate, KCl and NH3The method for preparing high-purity potassium sulfate, chlorine-based compound fertilizer and caprolactam by reaction comprises the following specific steps:
1) weighing caprolactam sulfate (w caprolactam =45%, w sulfuric acid = 55%) and KCl according to the mass ratio of 1:1.67, adding 1.5 times of water by mass to dissolve the caprolactam sulfate, and adding 1.5 times of water by mass to dissolve the KCl; then uniformly mixing the obtained solution, putting the mixed solution into a reaction tank, introducing ammonia gas into a reaction kettle, maintaining the pH value at 5.0-6.5, and reacting for 20 minutes at 60 ℃;
2) and concentrating and crystallizing the obtained material, filtering at 40 ℃, and washing the filter cake with water to obtain filtrate I. The filter residue after washing is K2SO4，K2SO4Filtering and washing to obtain high-purity K2SO4And filtrate II, and returning the filtrate II to the reaction tank in the step 1) for recycling. K2SO4After drying, the purity is 99.0%.
3) And adding benzene into the filtrate I obtained in the step 2 according to the volume ratio of 5:1 for extraction, fully stirring, standing for layering, and separating to obtain an organic phase and a water phase.
4) Adding 0.5 time of water into the organic phase obtained in the step 3) for back extraction to obtain a water phase, and evaporating the obtained water phase to dryness to obtain a caprolactam product, wherein the purity of the caprolactam product is 99.4 percent, and the yield of the caprolactam is 98.9 percent.
5) And 3) concentrating and crystallizing the water phase obtained in the step 3), filtering, returning filtrate obtained after filtering to the reaction tank in the step 1 for recycling, and using filter residues for producing the chlorine-based compound fertilizer.
Claims (9)
1. A method for preparing high-purity sulfate and by-producing caprolactam from caprolactam sulfate is characterized by comprising the following steps:
A. calculating the amount of caprolactam sulfate and alkali according to the stoichiometric number of the caprolactam sulfate and the alkali, respectively adding water for dissolving and size mixing, and then putting into a reaction tank for reaction;
B. filtering the material prepared in the step A, and washing a filter cake with water to obtain a filtrate I; adjusting the pH value of the washed filter residue to 6.0-7.0 to obtain sulfate, filtering the sulfate and washing the sulfate with water to obtain high-purity sulfate and filtrate II;
C. adding benzene into the filtrate I obtained in the step B for extraction, stirring, standing for layering, and separating to obtain an organic phase and a water phase;
D. adding water into the organic phase obtained in the step C for back extraction to obtain a water phase, evaporating the obtained water phase to obtain a caprolactam product, and purifying the oil phase for recycling;
the preparation of the high-purity calcium sulfate and the byproduct caprolactam are finished by using the caprolactam sulfate.
2. The method of claim 1, wherein: in the step A, the mass fraction of caprolactam in the caprolactam sulfate is 40-50%, and the mass fraction of sulfuric acid is 50-60%.
3. The method of claim 1, wherein: the water adding amount in the step A is 1.2 to 1.8 times of the total mass of caprolactam sulfate and alkali.
4. The method of claim 1, wherein: in the step A, the reaction temperature is 30-95 ℃, and the reaction time is 10-35 minutes.
5. The method of claim 1, wherein: and returning the filtrate II in the step B and the water phase obtained in the step C to the reaction tank in the step A for recycling.
6. The method of claim 1, wherein: in the step C, the filtrate I is prepared from the following raw materials in a volume ratio of (4-6): 1 benzene was added for extraction.
7. The method of claim 1, wherein: and in the step D, adding 0.3-0.6 time of water into the organic phase obtained in the step C for back extraction.
8. The method according to any one of claims 1 to 7, wherein: the base in the step A can also be alkaline oxide or chloride or alkaline carbonate or the combination thereof, and the base is KOH or Ca (OH)2The basic oxide is CaO or K2O, chloride is KCl or CaCl2The basic carbonate is K2CO3Or CaCO3。
9. The method of claim 8, wherein: when the alkali in the step A is chloride: and B, maintaining the pH value of the reaction in the reaction tank in the step A to be 5.0-6.5 by introducing ammonia gas, concentrating and crystallizing the water phase obtained in the step C, filtering, returning the filtrate obtained after filtering to the reaction tank in the step A for recycling, and using the filter residue for producing the chlorine-based compound fertilizer.
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| CN114605323A (en) * | 2022-03-31 | 2022-06-10 | 湖北三宁化工股份有限公司 | Process for separating caprolactam from caprolactam sulfate |
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