CN103664650A - Method of preparing N-methyldiethanolamine at normal temperature - Google Patents
Method of preparing N-methyldiethanolamine at normal temperature Download PDFInfo
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- CN103664650A CN103664650A CN201210330519.7A CN201210330519A CN103664650A CN 103664650 A CN103664650 A CN 103664650A CN 201210330519 A CN201210330519 A CN 201210330519A CN 103664650 A CN103664650 A CN 103664650A
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Abstract
The invention relates to the technical field of synthesis of chemical products, and particularly relates to a method of preparing N-methyldiethanolamine (MDEA) at a normal temperature. The method comprises the following steps: 1, raw material preparation; 2, synthetic reaction; 3, flash amine removal; and 4, rectification and purification. The synthetic reaction is carried out at the normal temperature. After reaction, the product N-methyldiethanolamine is obtained through flashy separation and rectification and purification, wherein a heating device is arranged at the bottom of a flash tower in a flash amine removal stage, and flash and gas stripping effect are compounded to realize a better separating effect, so that the subsequent rectifying operation is more stable and better in effect. The method provided by the invention improves the utilization ratio of raw materials and optimizes the process at the same time. By reinforcing amine removal treatment, the rectifying operation is more stable, and the content of N-methyldiethanolamine is improved to over 98.5%.
Description
Technical field
The present invention relates to chemical products synthesis technical field, i.e. a kind of normal temperature preparation method of N methyldiethanol amine (MDEA).
Background technology
Increasingly stringent along with energy-intensive aggravation and environmental requirement, day by day increases the requirement of desulfurization and decarburization.The unstripped gas of Sweet natural gas, oil and processing industry thereof (as catalysis drying gas, coking dry gas, reacted gas, liquefied gas etc.) all contains a certain amount of H
2s and organosulfur are (as CS
2, COS, RSH, R-S-R ' etc.), carrying and first being processed must be removed totally.
N methyldiethanol amine (MDEA) is the organic amine solvent that is widely used in desulfurization and decarburization technique with a kind of, can be used for processing different H
2the sour gas of S concentration can remove sulfide and CO simultaneously
2, also can remove H by highly selective
2s and organosulfur etc.The advantages such as have energy consumption low, internal circulating load is low, and process cost is low.
The technological line of producing MDEA has four kinds: (1) formaldehyde and cyanoethanol shortening; (2) formaldehyde reacts with diethanolamine; (3) formaldehyde and diethanolamine shortening; (4) methylamine and reacting ethylene oxide.
In above-mentioned four kinds of synthetic methods, methylamine and reacting ethylene oxide method are the most frequently used, according to reaction process, can be divided into autoclave intermittently synthetic synthetic continuously with tubular type, its reaction pressure and temperature are conventionally higher, as described in patent CN101265195A, its reaction pressure is at 5～7MPa, and temperature is controlled at 133～137 ℃.
Summary of the invention
The present invention proposes a kind of reaction at normal temperatures and prepare the method for N methyldiethanol amine (MDEA)., comprise raw material preparation, synthesis procedure, the de-amine of flash distillation and rectification and purification etc.
N methyldiethanol amine (MDEA) becomes reaction principle as follows:
The main technical schemes of the inventive method: the preparation method of N methyldiethanol amine under normal temperature, is characterized in that comprising the following steps:
1) raw material preparation: first methylamine, deionized water are mixed to the circulation fluid of usining as building-up reactions, in solution, methylamine content is 25～35%;
2) building-up reactions: the circulate soln mixing is sent into reactor, pressure is adjusted to 1.5～3.0MPa, then passes into oxyethane and reacts, and wherein oxyethane and methylamine ratio are 1.8～2.2, temperature is controlled at 40～65 ℃, and reaction obtains the mixture that contains N methyldiethanol amine;
3) the de-amine of flash distillation: the mixture that contains N methyldiethanol amine is sent into flashing tower, and flashing tower pressure-controlling is at 0.8～1.5MPa, and column bottom temperature is controlled at 100～120 ℃; The methylamine steam at top is reclaimed and is sent into raw material preparation flow and recycle by condensation, contains the enrichment of mixture liquid of N methyldiethanol amine at the bottom of flashing tower.In the de-amine process of flash distillation, flashing tower bottom is with heating unit, compound by flash distillation and two kinds of separate modes of air lift, better the methylamine in mixture after building-up reactions is separated.
4) rectification and purification: the enrichment of mixture liquid that contains N methyldiethanol amine obtaining at the bottom of flashing tower is sent into and carried out the separated N methyldiethanol amine that obtains of rectification under vacuum in rectifying tower, pressure-controlling is at-0.10～-0.90MPa, at the bottom of still, temperature is 168～185 ℃, and tower top temperature is controlled at 163～168 ℃.
Preparation method of the present invention, a kind of typical technique is:
First methylamine, deionized water are mixed, as the circulate soln of building-up reactions, in the rear solution of mixing, methylamine content is 25～35%; The circulate soln mixing is sent into reactor, pressure is adjusted to 1.5～3.0Mpa by nitrogen, then passing into oxyethane reacts, wherein oxyethane and methylamine ratio are 1.8～2.2, by the feed rate of regulating ring oxidative ethane, temperature of reaction is controlled to 40～65 ℃, and reaction obtains the mixture that contains N methyldiethanol amine; Then mixture is sent in the flashing tower with the device heating, pressure-controlling is within the scope of 0.8～1.5Mpa, heat and control temperature within the scope of 90～110 ℃, the methylamine in mix products is flashed off, then by condensation, reclaiming and send into raw material preparation flow and recycle.At the bottom of flashing tower, contain the enrichment of mixture liquid by N methyldiethanol amine.Containing being sent what obtain at the bottom of flashing tower into by the enrichment of mixture liquid of N methyldiethanol amine in rectifying tower, carry out the separated N methyldiethanol amine that obtains of rectification under vacuum, purity can reach 98.5%.
In technique of the present invention, pressure-controlling is at 1.5～3.0MPa, and pass through the reinforced of reasonable gate ring oxidative ethane, and by temperature of reaction, be 40～65 ℃, in technical process simultaneously, will at the bottom of flashing tower, add heating unit, by flash distillation with air lift is combined, when having improved efficiency, simplified technical process.The present invention has improved the utilization ratio of raw material, has optimized technique simultaneously, by strengthening de-amine, processes, and distillation operation is more steady, and the content of product N methyldiethanol amine (MDEA) is brought up to more than 98.5%.
Accompanying drawing explanation
Fig. 1 is embodiment of the present invention preparation method's block flowsheet schematic diagram.
Embodiment
Following examples preparation process as shown in Figure 1.
First methylamine, deionized water are mixed, in the rear solution of mixing, methylamine content is 25～35%; The circulate soln mixing is sent into reactor, reaction pressure is adjusted to 1.5～3.0MPa by nitrogen, then passing into oxyethane reacts, wherein oxyethane and methylamine ratio are 1.8～2.2, by the feed rate of regulating ring oxidative ethane, temperature of reaction is controlled to 40～65 ℃, and reaction obtains the mixture that contains N methyldiethanol amine; The mixture that contains N methyldiethanol amine is sent in the flashing tower with the device of heating, pressure-controlling is within the scope of 0.8～1.5MPa, heat and control temperature within the scope of 90～110 ℃, methylamine in mix products is flashed off, then by condensation, reclaim and send into raw material preparation flow and recycle.At the bottom of flashing tower, contain the enrichment of mixture liquid by N methyldiethanol amine.Containing being sent what obtain at the bottom of flashing tower into by the enrichment of mixture liquid of N methyldiethanol amine in rectifying tower, carry out the separated N methyldiethanol amine that obtains of rectification under vacuum, purity can reach more than 98.5%.At the bottom of rectifying tower, gained residual solution reclaims and sends into raw material preparation flow in utilization.In the de-amine process of flash distillation, flashing tower bottom is with heating unit, compound by flash distillation and two kinds of separate modes of air lift, better the methylamine in mixture after building-up reactions is separated.
example 1:
Processing parameter: a. building-up reactions, pressure: 2.0～3.0MPa; Temperature: 50～65 ℃;
B. flash distillation takes off amine, pressure: 1.0～1.2MPa; Temperature: 110～120 ℃;
C. rectification and purification, pressure :～0.1MPa; Temperature at the bottom of still: 175～185 ℃, 163～168 ℃ of tower top temperatures.
Mass flow: organic amine 1.54kg/hr, oxyethane 4.65kg/hr, deionized water 3.60kg/hr, backflow amine water 4.35kg/h, initial fraction 2.65kg/hr.
Quality product: N methyldiethanol amine (MDEA), purity 99.1%.
example 2:
Processing parameter: a. building-up reactions, pressure: 1.5～2.0MPa; Temperature: 40～55 ℃;
B. flash distillation takes off amine, pressure: 1.0～1.2MPa; Temperature: 100～110 ℃;
C. rectification and purification, pressure :～0.1MPa; Temperature at the bottom of still: 168～175 ℃, 163～168 ℃ of tower top temperatures.
Mass flow: organic amine 31kg/hr, oxyethane 87.4kg/hr, deionized water 72.3kg/hr, backflow amine water 85.8kg/h, initial fraction 52.5kg/hr.
Quality product: N methyldiethanol amine (MDEA), purity 99.0%.
Claims (7)
1. a preparation method for N methyldiethanol amine under normal temperature, is characterized in that comprising the steps:
The methylamine solution of mass concentration 25～35% is sent in reactor, adjustment pressure is 1.5～3.0MPa, passing into oxyethane reacts, temperature of reaction is controlled at 40～65 ℃, after reaction, the mixture that contains N methyldiethanol amine obtaining is sent into flashing tower, and flashing tower pressure-controlling is at 0.8～1.5MPa, and column bottom temperature is controlled at 100～120 ℃; Top obtains methylamine steam; At the bottom of tower, obtain the enrichment of mixture liquid that contains N methyldiethanol amine, sent into and in rectifying tower, carry out the separated N methyldiethanol amine that obtains of rectification under vacuum.
2. preparation method according to claim 1, is characterized in that described oxyethane and methylamine mass ratio are 1.8 ~ 2.2.
3. preparation method according to claim 1, is characterized in that it is to control by the feed rate of regulating ring oxidative ethane that temperature of reaction is controlled at 40～65 ℃.
4. preparation method according to claim 1, the methylamine steam that it is characterized in that top is reclaimed and is sent into feed preparation unit and recycle by condensation.
5. preparation method according to claim 1, is characterized in that in the de-amine process of flash distillation, flashing tower bottom is with heating unit, compound by flash distillation and two kinds of separate modes of air lift.
6. preparation method according to claim 1, is characterized in that pressure-controlling in rectifying tower is at-0.10～-0.90Mpa, and at the bottom of still, temperature is 168～185 ℃, and tower top temperature is controlled at 163～168 ℃.
7. preparation method according to claim 1, is characterized in that in rectification under vacuum process, initial fraction is returned to feed preparation unit recycle.
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|---|---|---|---|
| CN201210330519.7A CN103664650A (en) | 2012-09-10 | 2012-09-10 | Method of preparing N-methyldiethanolamine at normal temperature |
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| CN201210330519.7A CN103664650A (en) | 2012-09-10 | 2012-09-10 | Method of preparing N-methyldiethanolamine at normal temperature |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110683962A (en) * | 2018-07-06 | 2020-01-14 | 中国石油化工股份有限公司 | Method for preparing N-methyldiethanolamine by micro-reaction synthesis |
| CN116283617A (en) * | 2023-05-16 | 2023-06-23 | 新疆科力新技术发展股份有限公司 | N-methyldiethanolamine and preparation method thereof |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101265195A (en) * | 2008-04-23 | 2008-09-17 | 顾泽元 | Method for preparing N-methyldiethanolamine |
-
2012
- 2012-09-10 CN CN201210330519.7A patent/CN103664650A/en active Pending
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101265195A (en) * | 2008-04-23 | 2008-09-17 | 顾泽元 | Method for preparing N-methyldiethanolamine |
Non-Patent Citations (1)
| Title |
|---|
| 韩晓红: "N-甲基二乙醇胺的合成及应用", 《大众标准化》, no. 9, 31 December 2003 (2003-12-31), pages 37 - 38 * |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110683962A (en) * | 2018-07-06 | 2020-01-14 | 中国石油化工股份有限公司 | Method for preparing N-methyldiethanolamine by micro-reaction synthesis |
| CN116283617A (en) * | 2023-05-16 | 2023-06-23 | 新疆科力新技术发展股份有限公司 | N-methyldiethanolamine and preparation method thereof |
| CN116283617B (en) * | 2023-05-16 | 2023-08-11 | 新疆科力新技术发展股份有限公司 | N-methyldiethanolamine and preparation method thereof |
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