CN115974701A - Dehydration method of N, N-2-methyl-1,3-propane diamine - Google Patents
Dehydration method of N, N-2-methyl-1,3-propane diamine Download PDFInfo
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- CN115974701A CN115974701A CN202310068335.6A CN202310068335A CN115974701A CN 115974701 A CN115974701 A CN 115974701A CN 202310068335 A CN202310068335 A CN 202310068335A CN 115974701 A CN115974701 A CN 115974701A
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- methyl
- propane diamine
- water
- sodium hydroxide
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- 238000000034 method Methods 0.000 title claims abstract description 14
- 230000018044 dehydration Effects 0.000 title abstract description 12
- 238000006297 dehydration reaction Methods 0.000 title abstract description 12
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 claims abstract description 60
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 43
- 230000008569 process Effects 0.000 claims abstract description 5
- 239000000843 powder Substances 0.000 claims abstract description 3
- 239000000203 mixture Substances 0.000 claims description 4
- 238000003756 stirring Methods 0.000 claims description 2
- 239000003513 alkali Substances 0.000 abstract description 10
- 238000006243 chemical reaction Methods 0.000 abstract description 8
- 239000011259 mixed solution Substances 0.000 abstract description 8
- 238000007112 amidation reaction Methods 0.000 abstract description 7
- 238000004519 manufacturing process Methods 0.000 abstract description 7
- 238000000926 separation method Methods 0.000 abstract description 7
- 239000000243 solution Substances 0.000 abstract description 7
- 229920006395 saturated elastomer Polymers 0.000 abstract description 4
- 239000002699 waste material Substances 0.000 abstract description 3
- 239000012024 dehydrating agents Substances 0.000 abstract description 2
- 230000009467 reduction Effects 0.000 abstract description 2
- KWYUFKZDYYNOTN-UHFFFAOYSA-M Potassium hydroxide Chemical compound [OH-].[K+] KWYUFKZDYYNOTN-UHFFFAOYSA-M 0.000 description 12
- YNQLUTRBYVCPMQ-UHFFFAOYSA-N Ethylbenzene Chemical compound CCC1=CC=CC=C1 YNQLUTRBYVCPMQ-UHFFFAOYSA-N 0.000 description 10
- 239000007864 aqueous solution Substances 0.000 description 6
- 230000009471 action Effects 0.000 description 4
- 238000001514 detection method Methods 0.000 description 4
- 239000000126 substance Substances 0.000 description 4
- 238000004821 distillation Methods 0.000 description 3
- 239000003960 organic solvent Substances 0.000 description 3
- 238000004064 recycling Methods 0.000 description 3
- 230000009435 amidation Effects 0.000 description 2
- 150000001408 amides Chemical class 0.000 description 2
- 239000002280 amphoteric surfactant Substances 0.000 description 2
- 239000007788 liquid Substances 0.000 description 2
- 238000002156 mixing Methods 0.000 description 2
- 239000000047 product Substances 0.000 description 2
- 238000011084 recovery Methods 0.000 description 2
- 238000010521 absorption reaction Methods 0.000 description 1
- 238000011938 amidation process Methods 0.000 description 1
- 238000013459 approach Methods 0.000 description 1
- 239000002585 base Substances 0.000 description 1
- 239000003795 chemical substances by application Substances 0.000 description 1
- 230000009615 deamination Effects 0.000 description 1
- 238000006481 deamination reaction Methods 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 150000004985 diamines Chemical class 0.000 description 1
- 238000004090 dissolution Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- -1 fatty amide tertiary amine Chemical class 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 239000013067 intermediate product Substances 0.000 description 1
- 238000003760 magnetic stirring Methods 0.000 description 1
- 230000007246 mechanism Effects 0.000 description 1
- 238000005191 phase separation Methods 0.000 description 1
- 239000002994 raw material Substances 0.000 description 1
- 239000000376 reactant Substances 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 239000004094 surface-active agent Substances 0.000 description 1
- 238000003786 synthesis reaction Methods 0.000 description 1
- 230000002194 synthesizing effect Effects 0.000 description 1
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Abstract
The invention relates to a dehydration method of N, N-2-methyl-1,3-propane diamine, belonging to a separation method, which is characterized in that sodium hydroxide powder is added into a mixed solution of N, N-2-methyl-1,3-propane diamine and water and is continuously stirred until sodium hydroxide is in a supersaturated state, after standing, the upper layer is N, N-2-methyl-1,3-propane diamine solution, and the lower layer is sodium hydroxide solution, thus completing dehydration. According to the dehydration method of the N, N-2-methyl-1,3-propane diamine, sodium hydroxide is used as a dehydrating agent, the affinity of the sodium hydroxide and water is utilized to compete for water in a mixed solution, the higher the alkali concentration is, the greater the degree of reduction of the water in the mixed solution is, until an alkali liquor is saturated, the water content of the N, N-2-methyl-1,3-propane diamine is reduced to a degree that the separation cannot be realized and the conversion rate and the yield of an amidation reaction are not influenced, and meanwhile, the problems that the excessive N, N-2-methyl-1,3-propane diamine is recycled, the production cost is saved, the waste treatment burden is reduced and the like in the process are solved.
Description
Technical Field
The invention belongs to a separation method, and particularly relates to a dehydration method of N, N-2-methyl-1,3-propane diamine.
Background
The amidation reaction section in the amide amphoteric surfactant production process is a process of reacting a reactant (a product obtained in the previous section) with N, N-2-methyl-1,3-propane diamine, water is generated in the reaction process, a product is fatty amide tertiary amine which is also an important intermediate product for synthesizing a plurality of amide amphoteric surfactants, N-2-methyl-1,3-propane diamine is in absolute excess, and after the reaction is finished, unreacted N, N-2-methyl-1,3-propane diamine is removed completely and then subjected to the next reaction. Water is also generally generated during the amidation process, and the existence of water can seriously affect the conversion rate and the yield of the amidation. N, N-2-methyl-1,3-propane diamine and water are two phases which are infinitely mutually soluble, and the effective separation of the two phases becomes one of the problems to be solved urgently by manufacturers. Some manufacturers choose to add a water-carrying agent, such as ethylbenzene. According to theory, ethylbenzene seems to be capable of effectively carrying water, and does not influence and participate in the reaction process, but the actual operation effect is far from ideal, and finally a mixture of N, N-2-methyl-1,3-propane diamine, ethylbenzene and water is formed, and after a long time, the mixture is seemingly divided into two phases, but through detection and analysis, the upper phase is mostly ethylbenzene, a small amount of N, N-2-methyl-1,3-propane diamine and water, and the lower phase is a small amount of ethylbenzene, a large amount of N, N-2-methyl-1,3-propane diamine and water. And the ratio of each component in each phase is unstable. Therefore, the separated mixed solution can not be recycled and separated, and the production cost is increased undoubtedly.
In addition, N, N-2-methyl-1,3-propane diamine is a common main production raw material in the surfactant production process, and has the advantages of high price, easy volatilization, large pungent smell, strong corrosivity and large difficulty in waste treatment.
Disclosure of Invention
The invention aims to overcome the defects of the prior art and provides a dehydration method of N, N-2-methyl-1,3-propane diamine.
The invention relates to a dehydration method of N, N-2-methyl-1,3-propane diamine, which is characterized in that sodium hydroxide powder is added into a mixed solution of N, N-2-methyl-1,3-propane diamine and water and is continuously stirred until the sodium hydroxide is in a supersaturated state, after standing, the upper layer is N, N-2-methyl-1,3-propane diamine solution, and the lower layer is sodium hydroxide solution, thus completing dehydration.
According to the dehydration method of the N, N-2-methyl-1,3-propane diamine, sodium hydroxide is used as a dehydrating agent, the affinity of the sodium hydroxide and water is utilized to compete for water in a mixed solution, the higher the alkali concentration is, the greater the degree of reduction of the water in the mixed solution is, until an alkali liquor is saturated, the water content of the N, N-2-methyl-1,3-propane diamine is reduced to a degree that the separation cannot be realized and the conversion rate and the yield of an amidation reaction are not influenced, and meanwhile, the problems that the excessive N, N-2-methyl-1,3-propane diamine is recycled, the production cost is saved, the waste treatment burden is reduced and the like in the process are solved.
Drawings
FIG. 1 is a schematic view of example 1 of the present invention;
FIG. 2 is a schematic view of example 3 of the present invention.
Description of the preferred embodiment
Example 1
As shown in figure 1, taking 25ml of N, N-2-methyl-1,3-propane diamine and 25ml of water, mixing uniformly in a 50ml test tube with a plug, standing for 10min, wherein the solution is light yellow, uniform and transparent, does not separate layers, is added with 1g of sodium hydroxide each time, is mixed, dissolved and then stands, the layering condition is observed, the volume ratio of the upper phase and the lower phase gradually approaches 1:1 along with the gradual increase of the alkali concentration and tends to be stable, and the upper phase is 97-98% of N, N-2-methyl-1,3-propane diamine and 3-2% of water after detection and analysis. The water content does not influence the reaction process basically and can be directly reused.
Example 2
100ml of N, N-2-methyl-1,3-propylene diamine aqueous solution with unknown proportion on a production device is taken and placed in a beaker, sodium hydroxide is gradually added under magnetic stirring until the sodium hydroxide is in a supersaturated state, the mixture is transferred into a separating funnel to stand for 30min, and after upper and lower two-phase liquid is respectively discharged, gas phase detection is carried out, the upper phase is 97.46 percent of N, N-2-methyl-1,3-propylene diamine, and the lower phase is 2.53 percent of N, N-2-methyl-1,3-propylene diamine.
Example 3
When the mixed solution is large in volume and contains more than 20 percent of water, a two-step water separation method is adopted:
the first step is as follows: n, N-2-methyl-1,3-propanediamine uses temperature rise to divide water as shown in FIG. 2 when V Water (W) :V Diamines 1:2, the total volume of the effluent from the atmospheric pressure temperature-rising water separation method is 49.19-54.05% at 125-135 deg.C of the oil bath. Namely, it is: after the deamination is stabilized at 135 ℃, the water content of the residual N, N-2-methyl-1,3-propane diamine is 3.25 percent and can be directly used for the amidation synthesis reaction; removing the solution to contain 61.3 percent of water;
the second step: dividing water for N, N-2-methyl-1,3-propane diamine by using alkaline substances, adding alkali to divide water for N, N-2-methyl-1,3-propane diamine aqueous solution containing 61.3% of water obtained in the first step, and finally obtaining 97.7% of N, N-2-methyl-1,3-propane diamine (mixing with N, N-2-methyl-1,3-propane diamine solution with the water content of 3.25% separated in the first step for recycling) and saturated aqueous solution containing a small amount of N, N-2-methyl-1,3-propane diamine (heating the aqueous solution to normal pressure or reducing the pressure to evaporate the water and recycling the aqueous solution for recycling).
Example 4
After amidation reaction, after distilling off N, N-2-methyl-1,3-propane diamine aqueous solution under reduced pressure at 65 ℃, carrying out alkaline water diversion, wherein the water content is relatively less (< 10%), so the alkali addition speed and the dissolution degree are required to be controlled, when sodium hydroxide is difficult to dissolve, namely the water diversion end point, absorption upper phase detection shows that the content of N, N-2-methyl-1,3-propane diamine is 98.06%.
The specific operation process of the dehydration method of N, N-2-methyl-1,3-propane diamine in the embodiments 1-4 of the present invention is as follows: gradually adding sodium hydroxide into the N, N-2-methyl-1,3-propane diamine recovery tank and continuously stirring until the alkali content reaches a super-saturated state or the layering proportion is relatively stable, opening a bottom valve of the kettle to discharge the lower-layer high-concentration alkali liquor into the distillation container until a small amount of N, N-2-methyl-1,3-propane diamine liquid is discharged, and stopping. The N, N-2-methyl-1,3-propanediamine remaining in the recovery tank was transferred to a N, N-2-methyl-1,3-propanediamine feed tank, and used for the next amidation reaction. And (3) carrying out reduced pressure distillation on the high-concentration alkali liquor in the distillation container to remove water to obtain solid sodium hydroxide which can be used for next dehydration of the N, N-2-methyl-1,3-propane diamine.
The action principle of the invention is different from the action principle of dehydrating an organic solvent by using potassium hydroxide in the chemical industry, the chemical industry adopts the potassium hydroxide to remove trace moisture from the organic solvent, and the action mechanism of the invention is that the potassium hydroxide absorbs water in the organic solvent by utilizing the adsorbability of the potassium hydroxide to the water to form a viscous flocculent substance, thereby achieving the aim of removing the water. The action principle of the invention is that the strong basicity of sodium hydroxide is utilized to reduce the polarity of N, N-2-methyl-1,3-propane diamine molecules, thereby reducing the binding force of the N, N-2-methyl-1,3-propane diamine molecules and water molecules and forming a two-phase separation state. With the increasing concentration of the strong base, the number of water molecules combined by the N, N-2-methyl-1,3-propane diamine molecule is reduced. Finally, the aim of dehydrating the N, N-2-methyl-1,3-propane diamine is achieved.
Claims (1)
- A process for dewatering N, N-2-methyl-1,3-propanediamine includes such steps as adding sodium hydroxide powder to the mixture of N, N-2-methyl-1,3-propanediamine and water while stirring until the sodium hydroxide is supersaturated, standing, adding N, N-2-methyl-1,3-propanediamine solution as upper layer and sodium hydroxide solution as lower layer, and dewatering.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202310068335.6A CN115974701A (en) | 2023-02-06 | 2023-02-06 | Dehydration method of N, N-2-methyl-1,3-propane diamine |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202310068335.6A CN115974701A (en) | 2023-02-06 | 2023-02-06 | Dehydration method of N, N-2-methyl-1,3-propane diamine |
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Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101085739A (en) * | 2007-07-04 | 2007-12-12 | 四川省乐山市福华农科投资集团有限责任公司 | Dehydration treatment method for triethylamine |
| CN113620813A (en) * | 2021-08-13 | 2021-11-09 | 中国天辰工程有限公司 | Preparation method of N, N-dimethyl-1, 3-propane diamine |
| CN115057784A (en) * | 2022-07-13 | 2022-09-16 | 山东胜邦绿野化学有限公司 | Method for treating octyl trichlamide wastewater |
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- 2023-02-06 CN CN202310068335.6A patent/CN115974701A/en active Pending
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101085739A (en) * | 2007-07-04 | 2007-12-12 | 四川省乐山市福华农科投资集团有限责任公司 | Dehydration treatment method for triethylamine |
| CN113620813A (en) * | 2021-08-13 | 2021-11-09 | 中国天辰工程有限公司 | Preparation method of N, N-dimethyl-1, 3-propane diamine |
| CN115057784A (en) * | 2022-07-13 | 2022-09-16 | 山东胜邦绿野化学有限公司 | Method for treating octyl trichlamide wastewater |
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