CN116283605A - Method for preparing dimethylamine hydrochloride by using ODPA (organic chemical vapor deposition) production wastewater and application - Google Patents
Method for preparing dimethylamine hydrochloride by using ODPA (organic chemical vapor deposition) production wastewater and application Download PDFInfo
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- XHFGWHUWQXTGAT-UHFFFAOYSA-N dimethylamine hydrochloride Natural products CNC(C)C XHFGWHUWQXTGAT-UHFFFAOYSA-N 0.000 title claims abstract description 90
- IQDGSYLLQPDQDV-UHFFFAOYSA-N dimethylazanium;chloride Chemical compound Cl.CNC IQDGSYLLQPDQDV-UHFFFAOYSA-N 0.000 title claims abstract description 90
- 239000002351 wastewater Substances 0.000 title claims abstract description 45
- QQGYZOYWNCKGEK-UHFFFAOYSA-N 5-[(1,3-dioxo-2-benzofuran-5-yl)oxy]-2-benzofuran-1,3-dione Chemical compound C1=C2C(=O)OC(=O)C2=CC(OC=2C=C3C(=O)OC(C3=CC=2)=O)=C1 QQGYZOYWNCKGEK-UHFFFAOYSA-N 0.000 title claims abstract description 39
- 238000004519 manufacturing process Methods 0.000 title claims abstract description 38
- 238000000034 method Methods 0.000 title claims abstract description 29
- 238000005229 chemical vapour deposition Methods 0.000 title abstract description 4
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 claims abstract description 82
- 239000000243 solution Substances 0.000 claims abstract description 61
- 238000010521 absorption reaction Methods 0.000 claims abstract description 37
- 239000003513 alkali Substances 0.000 claims abstract description 27
- 239000007864 aqueous solution Substances 0.000 claims abstract description 20
- 239000007788 liquid Substances 0.000 claims abstract description 20
- 239000003054 catalyst Substances 0.000 claims abstract description 16
- 238000005286 illumination Methods 0.000 claims abstract description 13
- 238000010438 heat treatment Methods 0.000 claims abstract description 12
- JONTXEXBTWSUKE-UHFFFAOYSA-N 2-(2-aminoethylsulfanyl)ethanamine Chemical compound NCCSCCN JONTXEXBTWSUKE-UHFFFAOYSA-N 0.000 claims abstract description 7
- 238000004821 distillation Methods 0.000 claims description 32
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 claims description 27
- 239000003507 refrigerant Substances 0.000 claims description 13
- 238000001816 cooling Methods 0.000 claims description 11
- DEIVNMVWRDMSMJ-UHFFFAOYSA-N hydrogen peroxide;oxotitanium Chemical group OO.[Ti]=O DEIVNMVWRDMSMJ-UHFFFAOYSA-N 0.000 claims description 11
- 238000010992 reflux Methods 0.000 claims description 8
- KWYUFKZDYYNOTN-UHFFFAOYSA-M Potassium hydroxide Chemical compound [OH-].[K+] KWYUFKZDYYNOTN-UHFFFAOYSA-M 0.000 claims description 6
- 238000005119 centrifugation Methods 0.000 claims description 6
- 239000012670 alkaline solution Substances 0.000 claims description 5
- 238000002360 preparation method Methods 0.000 claims description 2
- ZMXDDKWLCZADIW-UHFFFAOYSA-N N,N-Dimethylformamide Chemical compound CN(C)C=O ZMXDDKWLCZADIW-UHFFFAOYSA-N 0.000 abstract description 220
- ROSDSFDQCJNGOL-UHFFFAOYSA-N Dimethylamine Chemical compound CNC ROSDSFDQCJNGOL-UHFFFAOYSA-N 0.000 abstract description 122
- 239000006227 byproduct Substances 0.000 abstract description 11
- 238000004064 recycling Methods 0.000 abstract description 10
- 238000004065 wastewater treatment Methods 0.000 abstract description 4
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 37
- BDAGIHXWWSANSR-UHFFFAOYSA-M Formate Chemical compound [O-]C=O BDAGIHXWWSANSR-UHFFFAOYSA-M 0.000 description 15
- 238000005406 washing Methods 0.000 description 12
- 238000002425 crystallisation Methods 0.000 description 10
- 230000008025 crystallization Effects 0.000 description 10
- 230000000052 comparative effect Effects 0.000 description 9
- 238000006243 chemical reaction Methods 0.000 description 8
- 239000012452 mother liquor Substances 0.000 description 8
- 238000011084 recovery Methods 0.000 description 8
- 238000009833 condensation Methods 0.000 description 7
- 230000005494 condensation Effects 0.000 description 7
- 239000004642 Polyimide Substances 0.000 description 5
- 230000015556 catabolic process Effects 0.000 description 5
- 230000003197 catalytic effect Effects 0.000 description 5
- 238000006555 catalytic reaction Methods 0.000 description 5
- 238000006731 degradation reaction Methods 0.000 description 5
- 238000001704 evaporation Methods 0.000 description 5
- 239000012535 impurity Substances 0.000 description 5
- 229920001721 polyimide Polymers 0.000 description 5
- 238000000703 high-speed centrifugation Methods 0.000 description 3
- 229920006395 saturated elastomer Polymers 0.000 description 3
- 239000002699 waste material Substances 0.000 description 3
- UUNDNWJBWRANHC-UHFFFAOYSA-N 2-methyl-4-(2-methyl-1,3-dioxoisoindol-4-yl)oxyisoindole-1,3-dione Chemical compound C=12C(=O)N(C)C(=O)C2=CC=CC=1OC1=CC=CC2=C1C(=O)N(C)C2=O UUNDNWJBWRANHC-UHFFFAOYSA-N 0.000 description 2
- LYCAIKOWRPUZTN-UHFFFAOYSA-N Ethylene glycol Chemical compound OCCO LYCAIKOWRPUZTN-UHFFFAOYSA-N 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 2
- 229910052799 carbon Inorganic materials 0.000 description 2
- 238000000354 decomposition reaction Methods 0.000 description 2
- 230000000593 degrading effect Effects 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 230000007613 environmental effect Effects 0.000 description 2
- 239000002920 hazardous waste Substances 0.000 description 2
- 239000000178 monomer Substances 0.000 description 2
- 230000008569 process Effects 0.000 description 2
- 239000000047 product Substances 0.000 description 2
- 230000001737 promoting effect Effects 0.000 description 2
- 239000002904 solvent Substances 0.000 description 2
- 239000012855 volatile organic compound Substances 0.000 description 2
- HTSGKJQDMSTCGS-UHFFFAOYSA-N 1,4-bis(4-chlorophenyl)-2-(4-methylphenyl)sulfonylbutane-1,4-dione Chemical compound C1=CC(C)=CC=C1S(=O)(=O)C(C(=O)C=1C=CC(Cl)=CC=1)CC(=O)C1=CC=C(Cl)C=C1 HTSGKJQDMSTCGS-UHFFFAOYSA-N 0.000 description 1
- JBCHWGTZAAZJKG-UHFFFAOYSA-N 2-methyl-5-nitroisoindole-1,3-dione Chemical compound C1=C([N+]([O-])=O)C=C2C(=O)N(C)C(=O)C2=C1 JBCHWGTZAAZJKG-UHFFFAOYSA-N 0.000 description 1
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 1
- NIPNSKYNPDTRPC-UHFFFAOYSA-N N-[2-oxo-2-(2,4,6,7-tetrahydrotriazolo[4,5-c]pyridin-5-yl)ethyl]-2-[[3-(trifluoromethoxy)phenyl]methylamino]pyrimidine-5-carboxamide Chemical compound O=C(CNC(=O)C=1C=NC(=NC=1)NCC1=CC(=CC=C1)OC(F)(F)F)N1CC2=C(CC1)NN=N2 NIPNSKYNPDTRPC-UHFFFAOYSA-N 0.000 description 1
- GTDPSWPPOUPBNX-UHFFFAOYSA-N ac1mqpva Chemical compound CC12C(=O)OC(=O)C1(C)C1(C)C2(C)C(=O)OC1=O GTDPSWPPOUPBNX-UHFFFAOYSA-N 0.000 description 1
- 230000009471 action Effects 0.000 description 1
- 239000002585 base Substances 0.000 description 1
- 238000010923 batch production Methods 0.000 description 1
- 238000009835 boiling Methods 0.000 description 1
- 238000006482 condensation reaction Methods 0.000 description 1
- 238000010924 continuous production Methods 0.000 description 1
- 239000002826 coolant Substances 0.000 description 1
- 230000008878 coupling Effects 0.000 description 1
- 238000010168 coupling process Methods 0.000 description 1
- 238000005859 coupling reaction Methods 0.000 description 1
- 239000013078 crystal Substances 0.000 description 1
- 230000018044 dehydration Effects 0.000 description 1
- 238000006297 dehydration reaction Methods 0.000 description 1
- 238000001514 detection method Methods 0.000 description 1
- 238000005265 energy consumption Methods 0.000 description 1
- 239000002360 explosive Substances 0.000 description 1
- 238000002290 gas chromatography-mass spectrometry Methods 0.000 description 1
- 230000003301 hydrolyzing effect Effects 0.000 description 1
- WGCNASOHLSPBMP-UHFFFAOYSA-N hydroxyacetaldehyde Natural products OCC=O WGCNASOHLSPBMP-UHFFFAOYSA-N 0.000 description 1
- 239000003595 mist Substances 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000020477 pH reduction Effects 0.000 description 1
- 238000000746 purification Methods 0.000 description 1
- 239000002994 raw material Substances 0.000 description 1
- 238000001953 recrystallisation Methods 0.000 description 1
- 239000004065 semiconductor Substances 0.000 description 1
- 238000000926 separation method Methods 0.000 description 1
- 238000010025 steaming Methods 0.000 description 1
- 238000001308 synthesis method Methods 0.000 description 1
- 238000004448 titration Methods 0.000 description 1
- 238000012795 verification Methods 0.000 description 1
Classifications
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- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C209/00—Preparation of compounds containing amino groups bound to a carbon skeleton
- C07C209/62—Preparation of compounds containing amino groups bound to a carbon skeleton by cleaving carbon-to-nitrogen, sulfur-to-nitrogen, or phosphorus-to-nitrogen bonds, e.g. hydrolysis of amides, N-dealkylation of amines or quaternary ammonium compounds
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C209/00—Preparation of compounds containing amino groups bound to a carbon skeleton
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C209/00—Preparation of compounds containing amino groups bound to a carbon skeleton
- C07C209/82—Purification; Separation; Stabilisation; Use of additives
- C07C209/86—Separation
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C319/00—Preparation of thiols, sulfides, hydropolysulfides or polysulfides
- C07C319/14—Preparation of thiols, sulfides, hydropolysulfides or polysulfides of sulfides
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- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
Abstract
The invention relates to the technical field of wastewater treatment, in particular to a method for preparing dimethylamine hydrochloride by using ODPA (organic chemical vapor deposition) production wastewater and application thereof. The method specifically comprises the following operations: putting ODPA production wastewater into a rectifying tower, heating and distilling under vacuum, and introducing gas into a condenser; under the illumination, the non-condensable gas is washed by an alkali solution containing a catalyst, and then the gas is absorbed by a hydrochloric acid absorption liquid to obtain dimethylamine hydrochloride aqueous solution. The method can effectively separate N, N-dimethylformamide and dimethylamine from ODPA production wastewater, and after the dimethylamine is scrubbed by alkali solution and absorbed by hydrochloric acid, the obtained dimethylamine hydrochloride can be used as an organic byproduct for producing the aminoethyl thioether, thereby realizing the recycling utilization of dimethylamine hydrochloride.
Description
Technical Field
The invention relates to the technical field of wastewater treatment, in particular to a method for preparing dimethylamine hydrochloride by using ODPA (organic chemical vapor deposition) production wastewater and application thereof.
Background
Polyimide products have wide application in the fields of aerospace, motor wrapping, automobile industry, mechanical industry, light industry, electrical appliance industry, precision mechanical industry, electronic industry and the like. The large-scale application of polyimide on organic light emitting semiconductors (smart phones) has led to an explosive increase in the demand for Polyimide (PI), while ODPA (3, 3', 4' -diphenylether dianhydride) is an important monomer for the manufacture of polyimide. Thus, the demand for these base monomers for ODPA has also grown year by year. In the prior art, in the small-batch production of ODPA, some problems which are easy to solve and even neglect are highlighted in the mass continuous production process, and particularly, the problems in the aspect of environmental protection exist.
In the prior art, the main synthesis method of ODPA is that N, N-Dimethylformamide (DMF) is taken as a solvent, N-methyl-4-nitrophthalimide is taken as a raw material, oxo-bis- (N-methylphthalimide) is obtained through condensation reaction, and then the ODPA is obtained through hydrolytic acidification, recrystallization purification and dehydration. Wherein, in the reaction, after the coupling is completed, the compound II oxo-bis- (N-methylphthalimide) is separated out by adding water in a solvent. The ODPA of 1t can produce 8-10t of ODPA waste water, the ODPA waste water contains about 70% of N, N-dimethylformamide with mass concentration, 30% of water with mass concentration and dimethylamine, the water can promote the decomposition of the N, N-dimethylformamide to produce dimethylamine, dimethylamine gas can carry the N, N-dimethylformamide into a dimethylamine absorption system, when the dimethylamine absorption system uses hydrochloric acid solution to absorb dimethylamine, the N, N-dimethylformamide can also be absorbed by the hydrochloric acid solution, the N, N-dimethylformamide in the obtained dimethylamine hydrochloride exceeds the standard, and organic matters in the byproduct dimethylamine hydrochloride exceed the standard, so that the waste treatment can only be used as dangerous waste, the recycling of the byproducts can not be realized, and the resource waste is caused.
Therefore, there is an urgent need to develop a method for recovering and obtaining the dimethylamine hydrochloride which is an organic byproduct meeting the standard requirements from the ODPA production wastewater, so as to realize the recycling of the organic byproduct.
Disclosure of Invention
Aiming at the technical problems, the invention provides a method for preparing dimethylamine hydrochloride by using ODPA production wastewater and application thereof. The method can recover the organic byproduct dimethylamine hydrochloride meeting the standard requirement from the ODPA production wastewater, realize the recycling of the organic byproduct and avoid wasting resources.
In order to solve the technical problems, the invention adopts the following technical scheme:
in a first aspect, the invention provides a method for preparing dimethylamine hydrochloride by using ODPA production wastewater, which specifically comprises the following operations: putting ODPA production wastewater into a rectifying tower, heating and distilling under vacuum, and introducing gas into a condenser; under the illumination, the non-condensable gas is washed by an alkali solution containing a catalyst, and then the gas is absorbed by a hydrochloric acid absorption liquid to obtain dimethylamine hydrochloride aqueous solution.
According to the method, the ODPA production wastewater is heated and distilled in a rectifying tower to volatilize N, N-dimethylformamide and dimethylamine together with water to form steam, gas flows out from the top of the tower and enters a condenser to be cooled, the N, N-dimethylformamide is condensed, and dimethylamine in the gas is not condensed, so that the N, N-dimethylformamide and dimethylamine in the gas are effectively separated, and the noncondensable gas with greatly reduced N, N-dimethylformamide is obtained. Under the illumination condition, washing the noncondensable gas with an alkali solution containing a catalyst, and catalytically degrading N, N-dimethylformamide remained in the gas into dimethylamine and formate, wherein the formate is absorbed by the alkali solution and the dimethylamine exists in the gas; and then the dimethylamine in the gas is absorbed by hydrochloric acid absorption liquid, so that dimethylamine hydrochloride aqueous solution can be obtained. The dimethylamine hydrochloride in the aqueous solution can be used as an organic byproduct for producing the aminoethyl thioether, so that the recycling utilization of the dimethylamine hydrochloride is realized.
The method solves the problems that dimethylamine hydrochloride generated in the ODPA production wastewater recovery process in the prior art can only be treated as hazardous waste and cannot be recycled.
The gas washing operation can be carried out in a treatment tower, the catalyst is firstly dissolved in the alkali solution, and then the alkali solution with the catalyst dissolved therein is leached from the top of the treatment tower to carry out gas washing, thereby achieving the purpose of catalyzing and degrading the N, N-dimethyl formyl in the gas. It should be noted that: the formate is absorbed by reacting with the alkali in the alkali solution, and when the pH of the alkali solution is about 11, the alkali solution absorbs the formate to reach a saturated state, and at this time, a new alkali solution is needed to be replaced for gas washing to ensure the absorption effect. After the catalyst in the alkaline solution which is saturated with formate is filtered and recovered, the solution can be used as a carbon source of a biochemical pool to carry out environmental protection and biochemistry by utilizing the characteristic of good biodegradability of formate.
Preferably, the kettle temperature of the heating distillation is 105-110 ℃.
Preferably, the vacuum degree of the vacuum is-0.09 to-0.095 Mpa, and the reflux ratio is 1:3-4.
Preferably, the temperature of the refrigerant in the condenser is 35-45 ℃.
In the embodiment of the invention, under the vacuum degree of minus 0.09 to minus 0.095Mpa, the boiling point of N, N-dimethylformamide is 72-90 ℃, under the action of a refrigerant at 34-45 ℃, N, N-dimethylformamide contained in the gas can be condensed, but dimethylamine can not be condensed and continuously exists in the gas, so that the N, N-dimethylformamide existing in the gas is separated from dimethylamine to the greatest extent, and the exceeding of the residual N, N-dimethylformamide in the dimethylamine gas is avoided. The refrigerant can adopt water or glycol, preferably water, and Volatile Organic Compounds (VOC) can not be generated by condensing with water, so that the economic feasibility is high.
Preferably, the alkali solution is 15% -20% sodium hydroxide solution or 15% -20% potassium hydroxide solution, which are not limited herein.
In the embodiment of the invention, when the mass concentration of the sodium hydroxide solution or the potassium hydroxide solution is 15-20%, the viscosity of the alkali solution is lower, so that the viscosity of the alkali fog is lower, thereby being beneficial to the recycling of the alkali solution. When the mass concentration of the alkali solution is more than 30%, the viscosity of the alkali solution becomes large, so that the viscosity of the alkali mist becomes low, thereby being not beneficial to the recycling of the alkali solution.
The residual N, N-dimethylformamide in the gas can be converted into dimethylamine by washing the gas with the alkaline solution with the concentration, so that the residual N, N-dimethylformamide in the gas is removed, and the problem that the N, N-dimethylformamide in dimethylamine hydrochloride exceeds the standard and can only be used as hazardous waste disposal due to the fact that the N, N-dimethylformamide is entrained in dimethylamine gas to enter a dimethylamine absorption system is avoided.
Preferably, the catalyst is titanium trioxide, the illumination is 210-230nm illumination, preferably 220nm, and the catalytic degradation effect is optimal at 220 nm.
In the embodiment of the invention, the catalysis of the catalyst titanium trioxide and the energy provided by nanometer illumination can accelerate the speed of promoting the decomposition of N, N-dimethylformamide into dimethylamine and formate by the alkali solution.
Preferably, the mass ratio of the alkali solution to the catalyst is 1:0.002-0.005. The amount of the alkali solution is not specifically limited, and is only related to the wastewater treatment amount, but has little relation to promoting the N, N-dimethylformamide reaction.
Preferably, the hydrochloric acid absorption liquid is a hydrochloric acid solution with the mass concentration of 20-30%; and when the pH value of the hydrochloric acid absorption liquid is 3.5-4.5, replacing the hydrochloric acid absorption liquid with a new hydrochloric acid absorption liquid.
In the embodiment of the invention, the hydrochloric acid solution is used as the absorption liquid, dimethylamine in the gas is absorbed into dimethylamine hydrochloride water solution, when the pH of the hydrochloric acid solution is 3.5-4.5, the hydrochloric acid solution is saturated to absorb dimethylamine, the absorption is stopped, and a new hydrochloric acid solution is used as the absorption liquid.
Preferably, the above method for preparing dimethylamine hydrochloride further comprises: and (3) distilling the dimethylamine hydrochloride aqueous solution under reduced pressure, cooling and centrifuging to obtain dimethylamine hydrochloride.
Preferably, the distillation is reduced pressure distillation; the vacuum degree of the reduced pressure distillation is-0.09 to-0.095 Mpa, and the temperature is 65-85 ℃;
cooling to 25-35 ℃;
the rotational speed of the centrifugation is 400-450r/min, and the centrifugation time is 15-20min. The dimethylamine hydrochloride obtained is more humid when the rotational speed is lower or the centrifugation time is shorter.
In the embodiment of the invention, dimethylamine hydrochloride aqueous solution is distilled, water is removed, then the temperature is reduced to separate out crystals, and after centrifugation, mother liquor and dimethylamine hydrochloride are obtained by separation, the mother liquor can be used in the next batch of wastewater treatment process, and the dimethylamine hydrochloride can be used as an organic byproduct for preparing the aminoethyl thioether, so that the recycling of the organic byproduct is realized.
In a second aspect, the invention also provides the use of the aqueous dimethylamine hydrochloride solution or dimethylamine hydrochloride in the preparation of aminoethyl sulfide.
In the embodiment of the invention, dimethylamine hydrochloride aqueous solution or dimethylamine hydrochloride is used for preparing the aminoethyl thioether, so that the recycling of dimethylamine hydrochloride aqueous solution or dimethylamine hydrochloride is realized.
Detailed Description
The present invention will be described in further detail with reference to specific embodiments in order to make the objects, technical solutions and advantages of the present invention more apparent. It should be understood that the specific embodiments described herein are for purposes of illustration only and are not intended to limit the scope of the invention.
Example 1
1500kg of ODPA production wastewater of roughly distilled N, N-dimethylformamide is taken, the mass concentration of the N, N-dimethylformamide in the wastewater is detected to be 71.4%, the mass concentration of dimethylamine is 0.5%, and the balance is water and trace other impurities. The production wastewater is put into a rectifying tower for heating distillation, the kettle temperature is 105 ℃, the vacuum degree is controlled at-0.092 Mpa, the reflux ratio is controlled at 1:3, gas flows out from the top of the tower and enters a condenser, the condenser adopts 35 ℃ water as a refrigerant, and N, N-dimethylformamide is obtained by condensation recovery, wherein the dimethylamine content in the recovered N, N-dimethylformamide is 41ppm, and the recovered N, N-dimethylformamide can be directly used.
In the distillation process, noncondensable gas is introduced into a deep treatment tower, a 220nm energy lamp is turned on in the treatment tower, a 15% sodium hydroxide solution containing 0.3% wt of titanium trioxide is leached from the top of the treatment tower, gas washing is carried out, the catalysis of the catalyst titanium trioxide and the energy provided by nanometer illumination can accelerate the sodium hydroxide solution to promote the catalytic degradation of residual N, N-dimethylformamide in the gas into dimethylamine and formate, and the formate is absorbed by the sodium hydroxide solution, and the dimethylamine exists in the gas; 35kg of a 20% by mass hydrochloric acid solution absorption solution was used to absorb dimethylamine in the gas (when the pH of the hydrochloric acid solution was 4.2, absorption was stopped and a new 20% by mass hydrochloric acid absorption solution was used) to obtain dimethylamine hydrochloride aqueous solution.
Introducing dimethylamine hydrochloride water solution into a reduced pressure distillation reaction kettle, performing reduced pressure distillation, evaporating water at the kettle temperature of 80 ℃ under the vacuum degree of-0.090 Mpa, and cooling to 30 ℃ for crystallization; and (3) after crystallization, carrying out high-speed centrifugation, wherein the centrifugal speed is 450r/min, and the centrifugal time is 20min, so as to obtain dimethylamine hydrochloride mother liquor and 10.1kg dimethylamine hydrochloride.
Example 2
1500kg of ODPA production wastewater of roughly distilled N, N-dimethylformamide is taken, the mass concentration of the N, N-dimethylformamide in the wastewater is detected to be 70.19%, the mass concentration of dimethylamine is 0.51%, and the balance is water and trace other impurities. The production wastewater is put into a rectifying tower for heating distillation, the kettle temperature is 108 ℃, the vacuum degree is controlled at minus 0.090Mpa, the reflux ratio is controlled at 1:3.5, gas flows out from the top of the tower and enters a condenser, water with the temperature of 40 ℃ is adopted as a refrigerant in the condenser, and N, N-dimethylformamide is obtained by condensation recovery, wherein the dimethylamine content in the recovered N, N-dimethylformamide is 42ppm, and the recovered N, N-dimethylformamide can be directly used.
In the distillation process, noncondensable gas is introduced into a deep treatment tower, a 220 nanometer energy lamp is turned on in the treatment tower, potassium hydroxide solution with the mass concentration of 15% and containing 0.5% of titanium trioxide is leached from the top of the treatment tower, gas washing is carried out, the catalysis of the catalyst titanium trioxide and the energy provided by nanometer illumination can accelerate the potassium hydroxide solution to promote the catalytic degradation of N, N-dimethylformamide remained in gas into dimethylamine and formate, the formate is absorbed by the potassium hydroxide solution, and the dimethylamine exists in the gas; 28kg of 25% by mass hydrochloric acid absorption liquid was used to absorb dimethylamine in the gas (when the pH of the hydrochloric acid solution was 3.8, absorption was stopped and a new 25% by mass hydrochloric acid absorption liquid was used) to obtain dimethylamine hydrochloride aqueous solution.
Introducing dimethylamine hydrochloride aqueous solution into a reduced pressure distillation reaction kettle, performing reduced pressure distillation, evaporating water at the kettle temperature of 75 ℃ under the vacuum degree of-0.095 Mpa, and cooling to 25 ℃ for crystallization; after crystallization is completed; high-speed centrifugation, wherein the centrifugal speed is 430r/min, and the centrifugal time is 20min, so as to obtain dimethylamine hydrochloride mother liquor and 10.3kg dimethylamine hydrochloride.
Example 3
1500kg of ODPA production wastewater of roughly distilled N, N-dimethylformamide is taken, the mass concentration of the N, N-dimethylformamide in the wastewater is detected to be 70.19%, and after the mass concentration of dimethylamine is 0.51%, the rest is water and trace other impurities. The production wastewater is put into a rectifying tower for heating distillation, the kettle temperature is 110 ℃, the vacuum degree is controlled at-0.095 Mpa, the reflux ratio is controlled at 1:4, gas flows out from the top of the tower and enters a condenser, water at 45 ℃ is adopted as a refrigerant in the condenser, and N, N-dimethylformamide is obtained through condensation recovery, wherein the dimethylamine content in the recovered N, N-dimethylformamide is 40ppm, and the recovered N, N-dimethylformamide can be directly used.
In the distillation process, noncondensable gas is introduced into a deep treatment tower, a 220 nanometer energy lamp is turned on in the treatment tower, a 15% sodium hydroxide solution containing 0.3% wt of titanium trioxide is leached from the top of the treatment tower, gas washing is carried out, the catalysis of the catalyst titanium trioxide and the energy provided by nanometer illumination can accelerate the sodium hydroxide solution to promote the catalytic degradation of residual N, N-dimethylformamide in the gas into dimethylamine and formate, the formate is absorbed by the sodium hydroxide solution, and the dimethylamine exists in the gas; 28kg of 30% by mass hydrochloric acid absorption solution was used to absorb dimethylamine in the gas (absorption was stopped when the pH of the hydrochloric acid solution was 4.5, and a new 30% by mass hydrochloric acid absorption solution was used) to obtain dimethylamine hydrochloride aqueous solution.
Introducing dimethylamine hydrochloride aqueous solution into a reduced pressure distillation reaction kettle, performing reduced pressure distillation, evaporating water at the kettle temperature of 65 ℃ under the vacuum degree of-0.092 Mpa, and cooling to 25 ℃ for crystallization; and (3) centrifuging at a high speed after crystallization is finished, wherein the centrifugal speed is 400r/min, and the centrifugal time is 20min, so as to obtain dimethylamine hydrochloride mother liquor and 10.4kg dimethylamine hydrochloride.
Comparative example 1
1500kg of ODPA production wastewater of roughly distilled N, N-dimethylformamide is taken, the mass concentration of the N, N-dimethylformamide in the wastewater is detected to be 71.4%, the mass concentration of dimethylamine is 0.5%, and the balance is water and trace other impurities. The production wastewater is put into a rectifying tower for heating distillation, the kettle temperature is 110 ℃, the vacuum degree is controlled at-0.095 Mpa, the reflux ratio is controlled at 1:3.5, gas flows out from the top of the tower and enters a condenser, the condenser adopts water at 7 ℃ as a refrigerant, and N, N-dimethylformamide is obtained through condensation recovery, wherein the content of dimethylamine in the recovered N, N-dimethylformamide is 0.12% of mass concentration, the dimethylamine content exceeds the standard, and the method does not meet the alkalinity requirement in industrial DMF and cannot be directly used.
In the distillation process, the gas noncondensable gas was introduced into a deep treatment column, and 5kg of a hydrochloric acid absorption liquid of 20% by mass concentration (when the pH of the hydrochloric acid solution was 4.0, absorption was stopped, and a new hydrochloric acid absorption liquid of 20% by mass concentration was used) was used to obtain a dimethylamine hydrochloride aqueous solution.
Introducing dimethylamine hydrochloride aqueous solution into a reduced pressure distillation reaction kettle, performing reduced pressure distillation, evaporating water at the kettle temperature of 75 ℃ under the vacuum degree of-0.095 Mpa, and cooling to 25 ℃ for crystallization; and (3) centrifuging at a high speed after crystallization is finished, wherein the centrifugal speed is 430r/min, and the centrifugal time is 20min, so as to obtain dimethylamine hydrochloride mother liquor and 10.1kg dimethylamine hydrochloride.
Comparative example 2
1500kg of ODPA production wastewater of roughly distilled N, N-dimethylformamide is taken, the mass concentration of the N, N-dimethylformamide in the wastewater is detected to be 71.4%, the mass concentration of dimethylamine is 0.5%, and the balance is water and trace other impurities. The production wastewater is put into a rectifying tower for heating distillation, the kettle temperature is 110 ℃, the vacuum degree is controlled at-0.095 Mpa, the reflux ratio is controlled at 1:3.5, gas flows out from the top of the tower and enters a condenser, the condenser adopts 35 ℃ water as a refrigerant, and N, N-dimethylformamide is obtained by condensation recovery, wherein the content of dimethylamine in the recovered N, N-dimethylformamide is 43ppm, and the recovered N, N-dimethylformamide can be directly used.
In the distillation process, the gas noncondensable gas is introduced into a deep treatment tower, 35kg of hydrochloric acid absorption liquid with the mass concentration of 20% (when the pH value of the hydrochloric acid solution is 4.2, absorption is stopped, and a new hydrochloric acid absorption liquid with the mass concentration of 20%) is used for obtaining dimethylamine hydrochloride water solution.
Introducing dimethylamine hydrochloride aqueous solution into a reduced pressure distillation reaction kettle, performing reduced pressure distillation, evaporating water at the kettle temperature of 75 ℃ under the vacuum degree of-0.095 Mpa, and cooling to 25 ℃ for crystallization; and (3) centrifuging at a high speed after crystallization is finished, wherein the centrifugal speed is 430r/min, and the centrifugal time is 20min, so as to obtain dimethylamine hydrochloride mother liquor and 10.2kg dimethylamine hydrochloride.
Comparative example 3
1500kg of ODPA production wastewater of roughly distilled N, N-dimethylformamide is taken, the mass concentration of the N, N-dimethylformamide in the wastewater is detected to be 71.4%, the mass concentration of water is 28.1%, and the mass concentration of dimethylamine is 0.5%. The production wastewater is put into a rectifying tower for heating distillation, the kettle temperature is 110 ℃, the vacuum degree is controlled at-0.092 Mpa, the reflux ratio is controlled at 1:3.5, gas flows out from the top of the tower and enters a condenser, the condenser adopts 35 ℃ water for cooling medium, and N, N-dimethylformamide is recovered, wherein the content of dimethylamine in the recovered N, N-dimethylformamide is 42.5ppm, and the recovered N, N-dimethylformamide can be directly used.
In the distillation process, the noncondensable gas is introduced into a deep treatment tower, a 220nm energy lamp is turned on in the treatment tower, water containing 0.3% wt of titanium trioxide is leached from the top of the treatment tower for gas washing, the catalysis of the catalyst titanium trioxide and the energy provided by nanometer illumination can accelerate the water to promote the catalytic degradation of residual N, N-dimethylformamide in the gas into dimethylamine and formate, and the formate is absorbed by the water, so that the dimethylamine exists in the gas; the gas after the gas washing was subjected to absorption of dimethylamine in the gas using 35kg of a 20% by mass hydrochloric acid absorption solution, and when the pH of the hydrochloric acid solution was 4.2, the absorption was stopped to obtain a dimethylamine hydrochloride aqueous solution.
Introducing dimethylamine hydrochloride aqueous solution into a reduced pressure distillation reaction kettle, performing reduced pressure distillation, steaming out water at the kettle temperature of 75 ℃ under the vacuum degree of-0.095 Mpa, and cooling to 25 ℃; high-speed centrifugation, wherein the centrifugal speed is 430r/min, and the centrifugal time is 20min, so as to obtain dimethylamine hydrochloride mother liquor and 10.2kg dimethylamine hydrochloride.
Verification example 1
The quality standard of the dimethylamine content in the N, N-dimethylformamide of the enterprise is less than or equal to 0.01 percent.
The quality standard of dimethylamine hydrochloride in enterprises is shown in table 1.
Table 1 quality standards for dimethylamine hydrochloride in enterprises
| Project | Index (I) |
| Dimethylamine hydrochloride content% mass concentration | ≥98.0 |
| pH value of | 3.5-5.0 |
| Moisture% mass concentration | ≤2.0 |
| DMF residual value | ≤50ppm |
Dimethylamine hydrochloride obtained in examples 1 to 3 and comparative examples 1 to 3 was measured, and the content of dimethylamine hydrochloride was measured by titration, water was measured by karl fischer method, acidity was measured by pH acidometer, and DMF residue was measured by gas chromatography-mass spectrometry. The detection results are shown in Table 2.
TABLE 2 dimethylamine hydrochloride test results obtained in examples 1-3 and comparative examples 1-3
As can be seen from a combination of tables 1 and 2, the dimethylamine hydrochloride obtained in examples 1-3 meets the enterprise dimethylamine hydrochloride quality standard, the dimethylamine hydrochloride obtained in comparative examples 1-3 does not meet the enterprise dimethylamine hydrochloride quality standard, and DMF residues are much greater than 50ppm in the quality standard.
In comparative example 1, water at 7 ℃ is adopted for refrigerant, the content of dimethylamine in the recovered N, N-dimethylformamide is 0.12% of mass concentration, which is far greater than the requirement that the mass standard of the content of dimethylamine in N, N-dimethylformamide in enterprises is less than or equal to 0.01% of mass concentration, and the content of dimethylamine exceeds the standard, which does not meet the alkalinity requirement in industrial DMF, and the N, N-dimethylformamide can not be directly used. Therefore, the refrigerant is carried out by adopting water at the temperature of 7 ℃, the N, N-dimethylformamide and dimethylamine in the gas cannot be effectively separated, and the dimethylamine can enter the N, N-dimethylformamide after condensation recovery, so that the dimethylamine content in the N, N-dimethylformamide exceeds the standard.
Compared with the comparative example 2 and the example 1-3, the hydrochloric acid solution is directly used for absorbing the gas without adopting an alkali solution for gas washing, and the DMF residue in the obtained dimethylamine hydrochloride is 0.92% of mass concentration and is far more than the requirement that the DMF residue in the quality standard of the enterprise dimethylamine hydrochloride is less than or equal to 50ppm.
Comparative example 3 compared with examples 1-3, the replacement of the alkaline solution with water resulted in a DMF residual of 0.12% by mass concentration in dimethylamine hydrochloride far exceeding the requirement of DMF residual of 50ppm or less in the enterprise dimethylamine hydrochloride mass standard.
Therefore, the invention adopts 35-45 ℃ water as a refrigerant, can effectively separate the N, N-dimethylformamide and dimethylamine in the ODPA production wastewater, and the dimethylamine content in the obtained N, N-dimethylformamide meets the standard requirement, meets the alkalinity requirement in industrial DMF, and can be directly used. The alkaline solution is helpful for maximally converting the residual N, N-dimethylformamide in the gas into dimethylamine, the dimethylamine hydrochloride obtained by absorbing the dimethylamine by hydrochloric acid has high purity, and the residual DMF is less than or equal to 50ppm, thereby meeting the quality standard requirements of dimethylamine hydrochloride of enterprises.
In conclusion, the method provided by the invention can effectively separate the N, N-dimethylformamide and dimethylamine in the ODPA production wastewater, and the obtained N, N-dimethylformamide and dimethylamine products all meet the quality standard. According to the method, N-dimethylformamide and dimethylamine hydrochloride in gas are separated by heating and distilling and cooling a condensed gas refrigerant, and the N, N-dimethylformamide can be directly used after condensation and recovery. And then washing with alkali solution, absorbing with hydrochloric acid to obtain dimethylamine hydrochloride as an organic byproduct, which can be used for preparing aminoethyl thioether, thereby realizing the recycling utilization of dimethylamine hydrochloride and N, N-dimethylformamide. The method also has the advantages of low energy consumption, low treatment cost, environment friendliness and safety.
The foregoing description of the preferred embodiments of the invention is not intended to be limiting, but rather is intended to cover all modifications, equivalents, or alternatives falling within the spirit and principles of the invention.
Claims (10)
1. The method for preparing dimethylamine hydrochloride by using ODPA production wastewater is characterized by comprising the following steps: putting ODPA production wastewater into a rectifying tower, heating and distilling under vacuum, and introducing gas into a condenser;
under the illumination, the non-condensable gas is washed by an alkali solution containing a catalyst, and then the gas is absorbed by a hydrochloric acid absorption liquid to obtain dimethylamine hydrochloride aqueous solution.
2. The method for preparing dimethylamine hydrochloride by using ODPA production wastewater according to claim 1, wherein the kettle temperature of the heating distillation is 105-110 ℃.
3. The method for preparing dimethylamine hydrochloride by using ODPA production wastewater according to claim 1, wherein the vacuum degree of the vacuum is-0.09 to-0.095 Mpa, and the reflux ratio is 1:3-4.
4. The method for preparing dimethylamine hydrochloride by using ODPA production wastewater according to claim 3, wherein the temperature of the refrigerant in the condenser is 35-45 ℃.
5. The method for preparing dimethylamine hydrochloride by using ODPA production wastewater according to claim 1, wherein the alkaline solution is 15-20% sodium hydroxide solution or 15-20% potassium hydroxide solution.
6. The method for preparing dimethylamine hydrochloride by using ODPA production wastewater according to claim 1, wherein the catalyst is titanium trioxide; and/or
The illumination is 210-230nm illumination; and/or
The mass ratio of the alkali solution to the catalyst is 1:0.002-0.005.
7. The method for preparing dimethylamine hydrochloride by using ODPA production wastewater according to claim 1, wherein the hydrochloric acid absorption liquid is a hydrochloric acid solution with the mass concentration of 20% -30%; and when the pH value of the hydrochloric acid absorption liquid is 3.5-4.5, replacing the hydrochloric acid absorption liquid with a new hydrochloric acid absorption liquid.
8. The method for preparing dimethylamine hydrochloride by using ODPA production wastewater according to claim 1, further comprising: distilling the dimethylamine hydrochloride aqueous solution, cooling and centrifuging to obtain dimethylamine hydrochloride.
9. The method for preparing dimethylamine hydrochloride by using ODPA production wastewater according to claim 8, wherein the distillation is reduced pressure distillation; the vacuum degree of the reduced pressure distillation is-0.09 to-0.095 Mpa, and the temperature is 65-85 ℃; and/or
Cooling to 25-35 ℃; and/or
The rotational speed of the centrifugation is 400-450r/min, and the centrifugation time is 15-20min.
10. Use of the dimethylamine hydrochloride solution obtained according to any of claims 1 to 7 or the dimethylamine hydrochloride obtained according to any of claims 8 to 9 for the preparation of aminoethyl sulfide.
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