阅读说明：本技术 一种n-甲基二异丙醇胺高效低耗连续化生产方法 (High-efficiency low-consumption continuous production method of N-methyl diisopropanolamine ) 是由 梁坤 林海飞 于 2021-07-15 设计创作，主要内容包括：本发明公开了一种N-甲基二异丙醇胺高效低耗连续化生产方法,属于涉及N-甲基二异丙醇胺高效低耗连续化生产技术领域,以甲基异丙醇胺和环氧丙烷为原料,在催化剂存在下,一步合成甲基二异丙醇胺,无须加大塔的回流比,大大节省了生产能耗,进一步降低了生产成本,操作方法简单、生产成本低、并能够适用于大规模生产的特点,实现新型的高效低耗连续性生产工艺技术的产业化及N-甲基二异丙醇胺产品的工业化生产。(The invention discloses a high-efficiency low-consumption continuous production method of N-methyl diisopropanolamine, belonging to the technical field of high-efficiency low-consumption continuous production of N-methyl diisopropanolamine.)

1. A high-efficiency low-consumption continuous production method of N-methyl diisopropanolamine is characterized by comprising the following steps: the method specifically comprises the following steps;

step one, metering methyl isopropanolamine and propylene oxide serving as raw materials respectively, continuously inputting the metered materials into a mixer, and fully mixing to obtain a uniformly mixed mixture; wherein methyl isopropanolamine and propylene oxide respectively enter the mixer through a metering pump with the outlet pressure of 0.5-4.0 MPa; wherein the molar ratio of methyl isopropanolamine to propylene oxide is 1: 0.8 to 0.98;

continuously feeding the mixture obtained in the step one into a reactor, adding a catalyst and a tertiary amine inhibitor, replacing air in the reactor with hydrogen, continuously introducing the hydrogen until the pressure in the reactor is 0.5-4.0 MPa, adjusting the temperature of the reactor, stirring for reaction, fully reacting the mixture in the reactor, and filtering to obtain a crude product containing N-methyl diisopropanolamine;

and step three, connecting a light component distillation tower and a methyl diisopropanolamine rectification tower in series, continuously feeding the crude product containing the N-methyl diisopropanolamine obtained in the step two into the middle of the rectification tower, feeding the crude product into the middle of the rectification tower, enabling the reaction tower to be provided with a stripping section and a rectification section and rectifying the crude product under a negative pressure state, adjusting the vacuum degree of the rectification tower, the tower top temperature and the tower kettle temperature of the rectification tower to enable rectification substances to be separated completely, further distilling out the methyl diisopropanolamine from the tower top, distilling out the N-methyl diisopropanolamine from the middle upper side line of the rectification tower to obtain a rectified product N-methyl diisopropanolamine, and refluxing the intermediate product which is distilled out from the tower top and does not participate in the reaction to a metering container for storing the methyl diisopropanolamine through a pipeline.

2. The continuous production method of N-methyl diisopropanolamine with high efficiency and low consumption as claimed in claim 1, characterized in that: the tertiary amine substance is selected from one of trimethylamine, triethylamine and tripropylamine, and the addition amount of the tertiary amine substance accounts for 1.0-3.0% of the total mass of all materials in the reaction system.

3. The continuous production method of N-methyl diisopropanolamine with high efficiency and low consumption as claimed in claim 1, characterized in that: the reaction of methyl isopropanol with propylene oxide is of the formula:

4. the continuous production method of N-methyl diisopropanolamine with high efficiency and low consumption as claimed in claim 1, characterized in that: the catalyst is selected from one of Raney nickel, Pd/C, Raney copper and copper chromite, and accounts for 0.5-3.0% of the total mass of all materials in the reaction system.

5. The continuous production method of N-methyl diisopropanolamine with high efficiency and low consumption as claimed in claim 1, characterized in that: the temperature of the reactor is 90-140 ℃, and the pressure is 3.5-5.5 MPa.

6. The continuous production method of N-methyl diisopropanolamine with high efficiency and low consumption as claimed in claim 1, characterized in that: in the second step, the reaction time of the mixture in the reactor is 5-10 min.

7. The continuous production method of N-methyl diisopropanolamine with high efficiency and low consumption as claimed in claim 1, characterized in that: in the third step, the vacuum degree of the rectifying tower is-0.09 MPa to-0.099 MPa, the tower top temperature of the rectifying tower is 60 ℃ to 110 ℃, and the tower kettle temperature of the rectifying tower is 110 ℃ to 160 ℃.

8. The continuous production method of N-methyl diisopropanolamine with high efficiency and low consumption as claimed in claim 1, characterized in that: in the third step, the methyl isopropanolamine distilled from the tower top returns to the container metering tank of the methyl isopropanolamine, and the methyl isopropanolamine continuously returns to the container metering tank of the methyl isopropanolamine through a pipeline.

Technical Field

The invention relates to the technical field of high-efficiency low-consumption continuous production of N-methyl diisopropanolamine, in particular to a high-efficiency low-consumption continuous production method of N-methyl diisopropanolamine.

Background

The N-methyl diisopropanolamine is MDIPA for short, is colorless transparent liquid with ammonia smell, can be dissolved in water, methanol and ethanol, is slightly dissolved in organic solvents such as toluene, acetone, petroleum ether and the like, has the specific gravity of 0.945g/cm3, the boiling point of 224 ℃, the flash point of 112.6 ℃, the viscosity of 2.353CP and the refractive index of 1.451 at normal temperature and normal pressure. The N-methyl diisopropanolamine MDIPA is a PO downstream alcohol amine chemical, has lower toxicity, good smell, stable structure and better stability after long-term storage, contains three methyl groups, two hydroxyl groups and an amino group, can reduce vapor pressure and increase solubility as a trialkanolamine product, is beneficial to absorption of acid gas, improves efficiency and reduces energy consumption, and is used for desulfurization, decarburization, surface activity, cutting fluid, lubricating oil, fiber textile auxiliary agents and the like.

In the prior art, an intermittent production process method is adopted for producing the N-methyl diisopropanolamine, the rectification process is intermittent, the improvement of the production capacity of the N-methyl diisopropanolamine is limited, the rectification is performed in a circulating way by steaming the first kettle and then steaming the second kettle, and an operator is required to continuously adjust the operation parameters of the rectification tower, so that the rectification tower cannot continuously and stably work, the material consumption and the energy consumption in the whole production process are high, the stability of the product quality is difficult to control and ensure, and the labor intensity of the operator is also high. Methyl diisopropanolamine production enterprises in China are rare, the independent innovation capability is low, and the production process is backward, so that the new process for developing a new technology is imperative. Therefore, in order to guarantee the product quality, reduce the material consumption and energy consumption in the production process and reduce the labor intensity of operators, the inventor has important significance in the development and industrialization of the high-efficiency low-consumption continuous production process technology for N-methyl diisopropanolamine.

In the current domestic research, all raw materials of alkylamine and alkylene oxide are mixed in advance, which not only has danger, but also causes the excess of alkyl monoethanol amine in the product because of improper modes and proportions of adding the raw materials of alkylamine and alkylene oxide, for example, a large amount of methyl monoethanol amine is generated in the process of producing the methyl diethanol amine, and the methyl monoethanol amine is continuously utilized as a circulating liquid, but also increases energy consumption, reduces the capacity of a reactor, and does not fundamentally improve the efficiency of the process flow. In addition, methylamine is primary amine, at least 2 units of propylene oxide are needed to react with N-methyl diisopropanolamine to obtain a high-content N-methyl diisopropanolamine product, the addition of a large amount of propylene oxide increases the probability of side reaction and also affects the chromaticity of the product, the feeding proportion of the propylene oxide is reduced, the separation problem of the N-methyl monoisopropanolamine and the N-methyl diisopropanolamine is caused, and the energy consumption of production is increased.

Patent CN102557960A provides a synthesis method, under the alkylation reaction conditions, alkylene oxide is contacted with alkylamine in a reactor for multiple times. The alkylene oxide reacts with the alkylamine for multiple times, so that the side reaction of the alkylene oxide is reduced, the output ratio adjusting range of the alkyl mono-alcohol amine and the alkyl di-alcohol amine is expanded, meanwhile, the raw materials are not required to be mixed in advance, the production safety is improved, in addition, the alkylene oxide enters in multiple points in a segmented mode, the reaction heat is released in a segmented mode, the reaction is more stable, in addition, the content of the mono-alkyl alcohol amine can be controlled, the mono-alkyl alcohol amine is not required to be used as a circulating liquid, and the reaction capacity is improved.

Patent CN105237412A proposes that diisopropanolamine and paraformaldehyde are used as raw materials, and diisopropanolamine is used as a depolymerizing agent of paraformaldehyde to reduce side reactions in the intermediate product synthesis stage, so as to prepare a high-purity intermediate product; meanwhile, a tertiary amine inhibitor is added in the hydrogenation reduction reaction stage, so that possible deamination reaction in the reaction process is avoided, and the yield of the synthesis reaction is improved.

The future development trend is to utilize the domestic abundant resources such as epoxy derivatives and the like to research the efficient, low-cost and simple continuous production technology of the N-methyl diisopropanolamine, and meet the development requirements of the current society on the high efficiency, energy conservation, environmental protection of the fine chemical production.

Disclosure of Invention

The invention aims to provide a high-efficiency low-consumption continuous production method of N-methyl diisopropanolamine, which takes methyl isopropanolamine and propylene oxide as raw materials, and can synthesize the methyl diisopropanolamine in one step in the presence of a catalyst without increasing the reflux ratio of a tower, thereby greatly saving the production energy consumption, further reducing the production cost, having the characteristics of simple operation method, low production cost and being suitable for large-scale production, and realizing the industrialization of a novel high-efficiency low-consumption continuous production process technology and the industrial production of an N-methyl diisopropanolamine product.

In order to achieve the above purpose, the invention provides the following technical scheme:

a high-efficiency low-consumption continuous production method of N-methyl diisopropanolamine specifically comprises the following steps;

step one, metering methyl isopropanolamine and propylene oxide serving as raw materials respectively, continuously inputting the metered materials into a mixer, and fully mixing to obtain a uniformly mixed mixture; wherein methyl isopropanolamine and propylene oxide respectively enter the mixer through a metering pump with the outlet pressure of 0.5-4.0 MPa; wherein the molar ratio of methyl isopropanolamine to propylene oxide is 1: 0.8 to 0.98;

continuously feeding the mixture obtained in the step one into a reactor, adding a catalyst and a tertiary amine inhibitor, replacing air in the reactor with hydrogen, continuously introducing the hydrogen until the pressure in the reactor is 0.5-4.0 MPa, adjusting the temperature of the reactor, stirring for reaction, fully reacting the mixture in the reactor, and filtering to obtain a crude product containing N-methyl diisopropanolamine;

and step three, connecting a light component distillation tower and a methyl diisopropanolamine rectification tower in series, continuously feeding the crude product containing the N-methyl diisopropanolamine obtained in the step two into the middle of the rectification tower, feeding the crude product into the middle of the rectification tower, enabling the reaction tower to be provided with a stripping section and a rectification section and rectifying the crude product under a negative pressure state, adjusting the vacuum degree of the rectification tower, the tower top temperature and the tower kettle temperature of the rectification tower to enable rectification substances to be separated completely, further distilling out the methyl diisopropanolamine from the tower top, distilling out the N-methyl diisopropanolamine from the middle upper side line of the rectification tower to obtain a rectified product N-methyl diisopropanolamine, and refluxing the intermediate product which is distilled out from the tower top and does not participate in the reaction to a metering container for storing the methyl diisopropanolamine through a pipeline.

As a further preferable scheme of the high-efficiency low-consumption continuous production method of the N-methyl diisopropanolamine, the tertiary amine substance is selected from one of trimethylamine, triethylamine and tripropylamine, and the addition amount of the tertiary amine substance accounts for 1.0-3.0% of the total mass of all materials in the reaction system.

As a further preferable scheme of the high-efficiency low-consumption continuous production method of N-methyl diisopropanolamine, the reaction formula of methyl isopropanol and propylene oxide is as follows:

as a further preferable scheme of the high-efficiency low-consumption continuous production method of the N-methyl diisopropanolamine, the catalyst is selected from one of Raney nickel, Pd/C, Raney copper and copper chromite, and accounts for 0.5-3.0% of the total mass of all materials in the reaction system.

As a further preferable scheme of the high-efficiency low-consumption continuous production method of the N-methyl diisopropanolamine, the temperature of the reactor is 90-140 ℃, and the pressure is 3.5-5.5 MPa.

As a further preferable scheme of the high-efficiency low-consumption continuous production method of N-methyl diisopropanolamine, in the second step, the reaction time of the mixture in the reactor is 5-10 min.

As a further preferable scheme of the high-efficiency low-consumption continuous production method of the N-methyl diisopropanolamine, the vacuum degree of the rectifying tower is-0.09 MPa to-0.099 MPa, the tower top temperature of the rectifying tower is 60 ℃ to 110 ℃, and the tower kettle temperature of the rectifying tower is 110 ℃ to 160 ℃.

In the third step, the methyl isopropanolamine distilled from the tower top returns to the container metering tank of the methyl isopropanolamine, and the methyl isopropanolamine continuously returns to the container metering tank of the methyl isopropanolamine through a pipeline.

In the technical scheme, the invention provides the following technical effects and advantages:

1. the invention adopts a continuous mode to separate and purify the N-methyl diisopropanolamine, fills the blank of high-efficiency batch production of the N-methyl diisopropanolamine in the industry, adopts an intermittent rectification technology in the prior art, has continuous reaction and amine evaporation processes and intermittent rectification process, limits the improvement of the production capacity of the N-methyl diethanolamine, can continuously produce by only setting the parameters of each tower kettle in the currently adopted continuous production mode, can realize continuous separation and purification of the N-methyl diisopropanolamine only by rectification of one rectification tower, not only can save production equipment, but also can omit the step of continuously monitoring the equipment parameters by manpower, thereby saving labor cost, ensuring and improving the production stability and further improving the quality and the yield of products.

2. Methyl isopropanolamine and propylene oxide are used as raw materials, a conventional methylamine-propylene oxide synthesis method with more side reactions is abandoned, on one hand, the equipment utilization rate is increased, on the other hand, the generation of polyether byproducts formed by polymerization of propylene oxide and alcohol amine substances is avoided, the probability of side reactions is reduced, the utilization rate of propylene oxide is greatly improved, the continuous operation is facilitated, and the method has the advantages of mild reaction conditions, high conversion rate, high yield of target products, simple and convenient treatment of crude products and the like.

3. The continuous production process of the project produces the N-methyl diisopropanolamine without increasing the reflux ratio of a tower, greatly saves the production energy consumption, further reduces the production cost, has the characteristics of simple operation method and low production cost, can be suitable for large-scale production, and realizes the industrialization of novel high-efficiency low-consumption continuous production process technology and the industrial production of N-methyl diisopropanolamine products.

Detailed Description

The present invention will be described in further detail below in order to enable those skilled in the art to better understand the technical solution of the present invention.

The content of the main embodiment of the high-efficiency low-consumption continuous production process of the N-methyl diisopropanolamine of the invention is as follows: the conventional methylamine-propylene oxide synthesis method with more side reactions is abandoned, and the research adopts methylisopropanolamine and propylene oxide as main raw materials, so that the application of other conventional alkaline depolymerizing agents is avoided, and the side reactions in the intermediate product synthesis stage are reduced, thereby preparing the high-purity intermediate product.

The synthesis route of the N-methyl diisopropanolamine is further researched under different conditions, the process parameters are repeatedly optimized by researching the control conditions of the charge ratio, the temperature, the pressure and the like of the reaction synthesis of the methyl diisopropanolamine and the propylene oxide, the production stability of the N-methyl diisopropanolamine is improved, the production flow is simplified, and the efficient and batch continuous production of the N-methyl diisopropanolamine is realized.

The application and control of the light component distillation tower and the methyl diisopropanolamine rectification tower are further researched, the circulating decomposition in continuous production is selected, the continuous and stable operation of the production process is ensured, the heat transfer and mass transfer efficiency is improved, a novel process route for preparing the N-methyl diisopropanolamine is formed, and corresponding matched production equipment is perfected.

The method specifically comprises the following steps:

a high-efficiency low-consumption continuous production method of N-methyl diisopropanolamine specifically comprises the following steps;

step one, metering methyl isopropanolamine and propylene oxide serving as raw materials respectively, continuously inputting the metered materials into a mixer, and fully mixing to obtain a uniformly mixed mixture; wherein methyl isopropanolamine and propylene oxide respectively enter the mixer through a metering pump with the outlet pressure of 0.5-4.0 MPa; wherein the molar ratio of methyl isopropanolamine to propylene oxide is 1: 0.8 to 0.98;

continuously feeding the mixture obtained in the step one into a reactor, adding a catalyst and a tertiary amine inhibitor, replacing air in the reactor with hydrogen, continuously introducing the hydrogen until the pressure in the reactor is 0.5-4.0 MPa, adjusting the temperature of the reactor, stirring for reaction, fully reacting the mixture in the reactor, and filtering to obtain a crude product containing N-methyl diisopropanolamine;

and step three, connecting a light component distillation tower and a methyl diisopropanolamine rectification tower in series, continuously feeding the crude product containing the N-methyl diisopropanolamine obtained in the step two into the middle of the rectification tower, feeding the crude product into the middle of the rectification tower, enabling the reaction tower to be provided with a stripping section and a rectification section and rectifying the crude product under a negative pressure state, adjusting the vacuum degree of the rectification tower, the tower top temperature and the tower kettle temperature of the rectification tower to enable rectification substances to be separated completely, further distilling out the methyl diisopropanolamine from the tower top, distilling out the N-methyl diisopropanolamine from the middle upper side line of the rectification tower to obtain a rectified product N-methyl diisopropanolamine, and refluxing the intermediate product which is distilled out from the tower top and does not participate in the reaction to a metering container for storing the methyl diisopropanolamine through a pipeline.

A continuous production process is introduced in the synthesis process of methyl diisopropanolamine, methyl diisopropanolamine and propylene oxide are used as reaction raw materials, and methyl diisopropanolamine is synthesized in the presence of a catalyst in the next step, so that side reactions in the synthesis stage of an intermediate product are reduced, and a high-purity intermediate product is prepared.

Connecting a light component distillation tower and a methyl diisopropanolamine rectifying tower in series, and feeding materials from the middle part of the towers to ensure that the reaction towers are provided with a stripping section and a rectifying section; can carry out rectification under the negative pressure state, and can separate rectification substances completely by controlling the temperature at the top of the tower, the temperature at the bottom of the tower and the vacuum degree, thereby realizing the purpose of continuously producing the methyl diisopropanolamine.

The efficiency of continuously producing the methyl diisopropanolamine is further improved by side line extraction at the middle upper part of the methyl diisopropanolamine rectifying tower or continuous extraction of products at the top of the tower; the intermediate product distilled from the top of the tower and not reacted flows back to a container metering tank for storing methyl isopropanolamine through a pipeline for reuse, thereby saving raw materials.

Through repeated experiments, the proportion of the raw materials is adjusted, the influence of conditions such as temperature, air pressure and catalyst on the main reaction is researched, the optimal reaction air pressure and reaction temperature are determined, the occurrence of side reactions is reduced, and the energy consumption and material consumption in the production process are reduced. And meanwhile, when the reaction is carried out to a certain degree, the reaction is carried out again with the raw materials to generate a target product, so that the quality of the product N-methyl diisopropanolamine is further improved.

The tertiary amine substance is selected from one of trimethylamine, triethylamine and tripropylamine, and the addition amount of the tertiary amine substance accounts for 1.0-3.0% of the total mass of all materials in the reaction system.

The reaction of methyl isopropanol with propylene oxide is of the formula:

the generated N-methyl diisopropanolamine is colorless transparent liquid, the content of the N-methyl diisopropanolamine is more than or equal to 99.2 wt%, the sum of impurities such as water, primary amine, secondary amine and the like is less than or equal to 0.8 wt%, the chroma is less than or equal to 30, and the N-methyl diisopropanolamine has higher quality.

The catalyst is selected from one of Raney nickel, Pd/C, Raney copper and copper chromite, and accounts for 0.5-3.0% of the total mass of all materials in the reaction system.

The temperature of the reactor is 90-140 ℃, and the pressure is 3.5-5.5 MPa.

In the second step, the reaction time of the mixture in the reactor is 5-10 min.

In the third step, the vacuum degree of the rectifying tower is-0.09 MPa to-0.099 MPa, the tower top temperature of the rectifying tower is 60 ℃ to 110 ℃, and the tower kettle temperature of the rectifying tower is 110 ℃ to 160 ℃.

In the third step, the methyl isopropanolamine distilled from the tower top returns to the container metering tank of the methyl isopropanolamine, and the methyl isopropanolamine continuously returns to the container metering tank of the methyl isopropanolamine through a pipeline.

The N-methyl diisopropanolamine is separated and purified in a continuous mode, the blank of high-efficiency batch production of the N-methyl diisopropanolamine in the industry is filled, an intermittent rectification technology is adopted in the prior art, the processes of reaction and amine evaporation are continuous, the rectification process is intermittent, and the improvement of the production capacity of the N-methyl diethanolamine is limited. The continuous production mode adopted at present can continuously produce only by setting the parameters of each tower kettle, and can realize continuous separation and purification of the N-methyl diisopropanolamine only by rectification of one rectifying tower, thereby saving production equipment, avoiding the step of continuously monitoring the parameters of the equipment by manpower, saving labor cost, ensuring and improving the stability of production and further improving the quality and yield of products.

Methyl isopropanolamine and propylene oxide are used as raw materials, a conventional methylamine-propylene oxide synthesis method with more side reactions is abandoned, on one hand, the equipment utilization rate is increased, on the other hand, the generation of polyether byproducts formed by polymerization of propylene oxide and alcohol amine substances is avoided, the probability of side reactions is reduced, the utilization rate of propylene oxide is greatly improved, the continuous operation is facilitated, and the method has the advantages of mild reaction conditions, high conversion rate, high yield of target products, simple and convenient treatment of crude products and the like.

The continuous production process for producing the N-methyl diisopropanolamine does not need to increase the reflux ratio of a tower, greatly saves the production energy consumption, further reduces the production cost, has the characteristics of simple operation method, low production cost and suitability for large-scale production, and realizes the industrialization of a novel high-efficiency low-consumption continuous production process technology and the industrial production of an N-methyl diisopropanolamine product.

While certain exemplary embodiments of the present invention have been described above by way of illustration only, it will be apparent to those of ordinary skill in the art that the described embodiments may be modified in various different ways without departing from the spirit and scope of the invention. Accordingly, the foregoing description is illustrative in nature and is not to be construed as limiting the scope of the invention as claimed.