A kind of preparation method of monoethanol diisopropanolamine

Abstract

The invention discloses a method for preparing monoethanol diisopropanolamine, and belongs to the technical field of chemical building materials. The method for preparing monoethanol diisopropanolamine comprises the following steps: adding a catalyst to monoethanolamine heated to 30°C, stirring evenly, placing the obtained mixture into a reactor in a nitrogen atmosphere, and spraying propylene oxide into the reactor; performing a aging reaction after the addition is completed, cooling, and obtaining monoethanol diisopropanolamine. The method has a simple synthesis process, a low reaction temperature, a short reaction time, and the prepared monoethanol diisopropanolamine has high purity, few by-products, and low cost.

Description

Technical Field

[0001] The invention belongs to the technical field of chemical building materials, and in particular relates to a method for preparing monoethanol diisopropanolamine. Background Art

[0002] As a kind of fine chemical with surfactant function, amines are widely used in cement grinding aids. They play a role in grinding and increasing production in cement production, and can improve the strength of cement in cement application. The earliest substances used in cement grinding aids were triethanolamine and triisopropanolamine. Researchers found that diethanol monoisopropanolamine has the performance advantages of triethanolamine and triisopropanolamine, not only has excellent grinding performance, but also can significantly improve the early and late strength of cement. Therefore, it is widely used in cement grinding aids to replace other amine raw materials and become the most important raw material in cement grinding aids. However, in recent years, with the overcapacity of cement production and fierce market competition, many cement plants choose to use low-priced steel slag, slag, alkali slag and other industrial waste as admixtures to reduce costs. For this type of cement, the existing triethanolamine, diethanol monoisopropanolamine and other amines have no obvious reinforcing effect, while monoethanol diisopropanolamine has excellent reinforcing effect on this type of cement, so it is used in cement grinding aids.

[0003] At present, there are three main synthetic routes for monoethanol diisopropanolamine:

[0004] (1) Ammonia reacts with ethylene oxide and propylene oxide to synthesize monoethanol diisopropanolamine. This method is a three-stage series reaction, which is complex, difficult to purify the product, and requires large equipment investment. Industrial production has not yet been carried out;

[0005] (2) Diisopropanolamine reacts with ethylene oxide to produce monoethanol diisopropanolamine. Due to the limited source of diisopropanolamine, only a few manufacturers that produce diisopropanolamine by themselves currently adopt this route. In addition, the content of monoethanol diisopropanolamine in the product synthesized by this process route is less than 85%. It must be distilled to obtain a monoethanol diisopropanolamine product of more than 90%, and the product contains a relatively high amount of high-boiling point by-products.

[0006] (3) Monoethanolamine reacts with propylene oxide to generate monoethanol diisopropanolamine. This process has the advantages of low requirements for synthesis equipment and control methods, and good product quality and stability. However, there are few related technologies disclosed using this method. Manufacturers all adopt the synthesis method of dissolving monoethanolamine in water and then adding propylene oxide dropwise. The reaction temperature is high, there are many by-products, and only products with a purity of less than 90% can be obtained. In addition, ZL201310359544.2 discloses a preparation method for generating monoethanol diisopropanolamine by reacting monoethanolamine with propylene oxide, but the yield of the product obtained needs to be further improved. At the same time, the input of excessive propylene oxide in its embodiment will also have an adverse effect on the yield, by-products and cost. Summary of the invention

[0007] In view of the above technical problems, the present invention provides a method for preparing monoethanol diisopropanolamine. The method has simple synthesis process, low reaction temperature, short reaction time, high purity of prepared monoethanol diisopropanolamine, few by-products and low cost.

[0008] To achieve the above object, the present invention provides the following technical solutions:

[0009] A method for preparing monoethanol diisopropanolamine comprises the following steps: adding a catalyst to monoethanolamine heated to 30°C, stirring the mixture, placing the obtained mixture into a reactor in a nitrogen atmosphere, and spraying propylene oxide into the reactor; performing a aging reaction after the addition is completed, cooling, and obtaining the monoethanol diisopropanolamine; the catalyst is a heteropolyacid catalyst, specifically phosphomolybdic acid, silicomolybdic acid, phosphotungstic acid or silicotungstic acid.

[0010] Furthermore, the mass ratio of the catalyst to monoethanolamine is (0.4-0.6):100; and the molar ratio of propylene oxide to monoethanolamine is (1.95-2.0):1.0.

[0011] Furthermore, the purity of the monoethanolamine is ≥99.5%; the purity of the propylene oxide is ≥99.5%.

[0012] Furthermore, the parameters in the process of spraying propylene oxide into the reactor are: temperature 50-70° C., pressure 0.3-0.5 MPa, and propylene oxide addition time 120-260 min.

[0013] Furthermore, the parameters of the aging reaction are: temperature 50-70°C, time 30-60min.

[0014] Furthermore, the reactor is a Venturi jet loop reactor.

[0015] The present invention also provides monoethanol diisopropanolamine prepared by the preparation method.

[0016] The invention also provides an application of monoethanol diisopropanolamine as a cement grinding aid material.

[0017] Compared with the prior art, the present invention has the following advantages and technical effects:

[0018] The invention provides a method for synthesizing high-purity monoethanol diisopropanolamine, which has the advantages of stable and controllable reaction exotherm, short reaction time, high hourly output, simple synthesis process, high product purity, low energy consumption, low cost and the like.

[0019] The invention uses heteropoly acid as a catalyst for monoethanolamine and propylene oxide to prepare monoethanol diisopropanolamine, which greatly improves the reaction rate and product conversion rate, thereby obtaining a monoethanol diisopropanolamine product with high purity and good quality. Moreover, due to the improved reaction rate, the reaction time is greatly shortened, the unit output is improved, and the product cost is reduced. DETAILED DESCRIPTION

[0020] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as limiting the present invention, but should be understood as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0021] It should be understood that the terms described in the present invention are only for describing special embodiments and are not intended to limit the present invention. In addition, for the numerical range in the present invention, it should be understood that each intermediate value between the upper and lower limits of the scope is also specifically disclosed. Each smaller range between the intermediate value in any stated value or stated range and any other stated value or intermediate value in the described range is also included in the present invention. The upper and lower limits of these smaller ranges can be independently included or excluded in the scope.

[0022] Unless otherwise indicated, all technical and scientific terms used herein have the same meanings as those generally understood by those skilled in the art. Although the present invention describes only preferred methods and materials, any methods and materials similar or equivalent to those described herein may also be used in the implementation or testing of the present invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials associated with the documents. In the event of a conflict with any incorporated document, the content of this specification shall prevail.

[0023] It will be apparent to those skilled in the art that various modifications and variations may be made to the specific embodiments of the present invention description without departing from the scope or spirit of the present invention. Other embodiments derived from the present invention description will be apparent to those skilled in the art. The present invention description and examples are exemplary only.

[0024] The words “include,” “including,” “have,” “contain,” etc. used in this document are open-ended terms, meaning including but not limited to.

[0025] The raw materials used in the present invention are all purchased from the market.

[0026] The present invention provides a method for preparing monoethanol diisopropanolamine, comprising the following steps:

[0027] (1) Add monoethanolamine to a stirred tank, heat to 30°C, add a catalyst, stir for 30 minutes, mix well, and then transfer to a subsequent reactor;

[0028] (2) after displacing all the air in the reactor and the external circulation condenser with nitrogen, the monoethanolamine and catalyst mixture prepared in step (1) are added into the reactor, and then the reactor is filled with nitrogen and pressurized to 0.2 MPa;

[0029] (3) opening the external circulation condenser, spraying propylene oxide into the reactor, controlling the reaction temperature to 50-70°C (preferably 50°C, 60°C, 65°C or 70°C), the pressure to 0.3-0.5Mpa (preferably 0.3Mpa, 0.4Mpa or 0.5Mpa), and the propylene oxide addition time to 120-260min (preferably 120min, 180min, 200min, 240min, 250min or 260min);

[0030] (4) After the addition of propylene oxide is completed, the reaction temperature is maintained at 50-70° C. (preferably 50° C., 55° C., 65° C. or 70° C.), and the aging reaction is carried out for 30-60 min (preferably 30 min, 40 min, 50 min or 60 min), and then cooled to obtain the product monoethanol diisopropanolamine.

[0031] In the following preferred embodiment step 1) of the present invention, the catalyst is a heteropolyacid catalyst, and more preferably a heteropolyacid catalyst includes phosphomolybdic acid, silicomolybdic acid, phosphotungstic acid or silicotungstic acid, and more preferably phosphomolybdic acid or silicomolybdic acid.

[0032] The mass ratio of the catalyst to monoethanolamine is (0.4-0.6):100, preferably 0.4:100, 0.5:100 or 0.6:100.

[0033] In step 3) of the following preferred embodiment of the present invention, the molar ratio of propylene oxide to monoethanolamine is (1.95-2.0):1.0, preferably (1.98-2.0):1.0, more preferably 1.98:1, 1.99:1 or 2:1. The reactor is a Venturi jet loop reactor.

[0034] The present invention adopts heteropoly acid as catalyst, and uses venturi jet loop reactor as reactor to be applied to alkoxylation reaction of amine, and has the advantages of fast response speed, good selectivity, few by-products, high product purity, simple process, short synthesis cycle, etc. Catalyst heteropoly acid is an oxygen-containing polyacid composed of heteroatoms (P, Si, Fe, Co, etc.) and polyatoms (Mo, W, V, Nb, Ta, etc.) through oxygen atom coordination bridging according to a certain structure, and is a protonic acid with uniform strength. Heteropoly acid has very high catalytic activity, and its structure is determined, catalytic performance is adjustable, and thermal stability is good, and it can be used for homogeneous and heterogeneous catalytic reaction systems. It is applied to the reaction of monoethanolamine and propylene oxide as catalyst, and rapid reaction under anhydrous state and low temperature conditions can be realized, thereby both the reaction rate can be improved, the generation of by-products such as isomers and etheramines can be avoided, and then the purity of the product can be improved. The use of a Venturi jet loop reactor with an external heat exchanger can, on the one hand, provide sufficient heat exchange, and the heat exchange area will not be limited by the reactor volume; on the other hand, in the Venturi ejector, a monoethanolamine liquid mixed with a heteropolyacid catalyst is sprayed through a nozzle to form a fluid with a high-speed shearing effect, which is strongly mixed and reacted with the introduced propylene oxide, thereby generating a larger contact surface area, improving the mass transfer rate under unit power consumption, and coupled with the catalytic effect of the high-efficiency catalyst, greatly improving the reaction rate and product conversion rate, thereby obtaining a monoethanol diisopropanolamine product with high purity and excellent quality, and because of the increased reaction rate, the reaction time is greatly shortened, the unit output is increased, and the product cost is reduced.

[0035] In the following examples of the present invention, the purity of the monoethanolamine is ≥99.5%; the purity of the propylene oxide is ≥99.5%.

[0036] The technical solution of the present invention is further illustrated by the following embodiments.

[0037] Example 1

[0038] A method for preparing monoethanol diisopropanolamine, comprising the following steps:

[0039] (1) adding monoethanolamine to a stirred tank, heating to 30° C., weighing phosphomolybdic acid and adding it to the stirred tank, the mass ratio of phosphomolybdic acid to monoethanolamine being 0.4% (i.e., 0.4:100, the same below), stirring for 30 minutes to mix evenly, and then transferring the mixture to a venturi jet loop reactor;

[0040] (2) After exhausting the air in the Venturi jet loop reactor and the external circulation condenser with nitrogen for three times, the monoethanolamine and catalyst mixture prepared in step (1) were added into the reactor, and then nitrogen was filled into the reactor to increase the pressure to 0.2 MPa, and the circulation pump was turned on to circulate the materials in the reactor;

[0041] (3) Spraying propylene oxide into the reactor, while turning on the external circulation condenser, controlling the reaction temperature to 50° C., the pressure to 0.3 MPa, and the propylene oxide addition time to 260 min; the molar ratio of propylene oxide to monoethanolamine is 2:1;

[0042] (4) After the addition of propylene oxide is completed, the reaction temperature is maintained at 50° C., the reaction is aged for 60 minutes, and the reaction is cooled to obtain the product monoethanol diisopropanolamine.

[0043] Example 2

[0044] A method for preparing monoethanol diisopropanolamine, comprising the following steps:

[0045] (1) adding monoethanolamine to a stirred tank, heating to 30° C., weighing phosphomolybdic acid and adding it to the stirred tank, the mass ratio of phosphomolybdic acid to monoethanolamine being 0.6%, stirring for 30 minutes to mix evenly, and then transferring the mixture to a venturi jet loop reactor;

[0046] (2) After exhausting the air in the Venturi jet loop reactor and the external circulation condenser with nitrogen for three times, the monoethanolamine and catalyst mixture prepared in step (1) were added into the reactor, and then nitrogen was filled into the reactor to increase the pressure to 0.2 MPa, and the circulation pump was turned on to circulate the materials in the reactor;

[0047] (3) Spraying propylene oxide into the reactor, while turning on the external circulation condenser, controlling the reaction temperature to 70° C., the pressure to 0.5 MPa, and the propylene oxide addition time to 120 min; the molar ratio of propylene oxide to monoethanolamine is 1.98:1;

[0048] (4) After the addition of propylene oxide is completed, the reaction temperature is maintained at 70° C., the reaction is aged for 30 minutes, and then cooled to obtain the product monoethanol diisopropanolamine.

[0049] Example 3

[0050] A method for preparing monoethanol diisopropanolamine, comprising the following steps:

[0051] (1) adding monoethanolamine to a stirred tank, heating to 30° C., weighing silicomolybdic acid and adding it to the stirred tank, the mass ratio of silicomolybdic acid to monoethanolamine being 0.5%, stirring for 30 minutes to mix evenly, and then transferring the mixture to a venturi jet loop reactor;

[0052] (2) After exhausting the air in the Venturi jet loop reactor and the external circulation condenser with nitrogen for three times, the monoethanolamine and catalyst mixture prepared in step (1) were added into the reactor, and then nitrogen was filled into the reactor to increase the pressure to 0.2 MPa, and the circulation pump was turned on to circulate the materials in the reactor;

[0053] (3) Spraying propylene oxide into the reactor, while turning on the external circulation condenser, controlling the reaction temperature to 65° C., the pressure to 0.4 MPa, and the propylene oxide addition time to 240 min; the molar ratio of propylene oxide to monoethanolamine is 1.99:1;

[0054] (4) After the addition of propylene oxide is completed, the reaction temperature is maintained at 65° C., the reaction is aged for 50 minutes, and the reaction is cooled to obtain the product monoethanol diisopropanolamine.

[0055] Example 4

[0056] A method for preparing monoethanol diisopropanolamine, comprising the following steps:

[0057] (1) adding monoethanolamine to a stirred tank, heating to 30° C., weighing phosphotungstic acid and adding it to the stirred tank, the mass ratio of phosphotungstic acid to monoethanolamine being 0.5%, stirring for 30 minutes to mix evenly, and then transferring to a venturi jet loop reactor;

[0058] (2) After exhausting the air in the Venturi jet loop reactor and the external circulation condenser with nitrogen for three times, the monoethanolamine and catalyst mixture prepared in step (1) were added into the reactor, and then nitrogen was filled into the reactor to increase the pressure to 0.2 MPa, and the circulation pump was turned on to circulate the materials in the reactor;

[0059] (3) Spraying propylene oxide into the reactor, while turning on the external circulation condenser, controlling the reaction temperature to 70° C., the pressure to 0.4 MPa, and the propylene oxide addition time to 180 min; the molar ratio of propylene oxide to monoethanolamine is 1.98:1;

[0060] After the addition of propylene oxide was completed, the reaction temperature was maintained at 70° C., the reaction was aged for 60 min, and the mixture was cooled to obtain the product monoethanol diisopropanolamine.

[0061] Example 5

[0062] A method for preparing monoethanol diisopropanolamine, comprising the following steps:

[0063] (1) adding monoethanolamine to a stirred tank, heating to 30° C., weighing phosphotungstic acid and adding it to the stirred tank, the mass ratio of phosphotungstic acid to monoethanolamine being 0.6%, stirring for 30 minutes to mix evenly, and then transferring to a venturi jet loop reactor;

[0064] (2) After exhausting the air in the Venturi jet loop reactor and the external circulation condenser with nitrogen for three times, the monoethanolamine and catalyst mixture prepared in step (1) were added into the reactor, and then nitrogen was filled into the reactor to increase the pressure to 0.2 MPa, and the circulation pump was turned on to circulate the materials in the reactor;

[0065] (3) Spraying propylene oxide into the reactor, while turning on the external circulation condenser, controlling the reaction temperature to 65° C., the pressure to 0.4 MPa, and the propylene oxide addition time to 200 min; the molar ratio of propylene oxide to monoethanolamine is 2:1;

[0066] (4) After the addition of propylene oxide is completed, the reaction temperature is maintained at 65° C., the reaction is aged for 40 minutes, and the reaction is cooled to obtain the product monoethanol diisopropanolamine.

[0067] Example 6

[0068] A method for preparing monoethanol diisopropanolamine, comprising the following steps:

[0069] (1) Monoethanolamine was added to a stirred tank and heated to 30° C. Silicate tungstic acid was weighed and added to the stirred tank. The mass ratio of silicotungstic acid to monoethanolamine was 0.5%. After stirring for 30 minutes and mixing evenly, the mixture was transferred to a Venturi jet loop reactor.

[0070] (2) After exhausting the air in the Venturi jet loop reactor and the external circulation condenser with nitrogen for three times, the monoethanolamine and catalyst mixture prepared in step (1) were added into the reactor, and then nitrogen was filled into the reactor to increase the pressure to 0.2 MPa, and the circulation pump was turned on to circulate the materials in the reactor;

[0071] (3) Spraying propylene oxide into the reactor, while turning on the external circulation condenser, controlling the reaction temperature to 50° C., the pressure to 0.4 MPa, and the propylene oxide addition time to 250 min; the molar ratio of propylene oxide to monoethanolamine is 1.99:1;

[0072] (4) After the addition of propylene oxide is completed, the reaction temperature is maintained at 55° C., the reaction is aged for 40 minutes, and then cooled to obtain the product monoethanol diisopropanolamine.

[0073] Comparative Example 1

[0074] Same as Example 2, except that the catalyst phosphomolybdic acid is not added.

[0075] Comparative Example 2

[0076] Same as Example 3, except that the Venturi jet loop reactor is replaced by a reactor with strong stirring.

[0077] Comparative Example 3

[0078] Same as Example 6, except that the mass ratio of the catalyst to the monoethanolamine is 0.35%.

[0079] Comparative Example 4

[0080] Same as Example 6, except that the molar ratio of propylene oxide to monoethanolamine is 2.05:1.0.

[0081] The components of the products obtained in Examples 1-7 and Comparative Examples 1-4 were analyzed using a Shimadzu GC-2030 gas chromatograph. The results are shown in Table 1.

[0082] Table 1 Component contents of products prepared by different methods

[0083]

[0084] It can be seen from the results in the above table that the effective ingredient content of the monoethanol diisopropanolamine product prepared by the method of the embodiment of the present invention is greater than 98.6%.

[0085] The above are only preferred specific implementations of the present application, but the protection scope of the present application is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed in the present application should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

Claims

1. A method for preparing monoethanol diisopropanolamine, characterized in that: The following steps are involved: Add monoethanolamine to a stirred tank, heat to 30°C, add a catalyst, stir well, and transfer to a subsequent reactor; after exhausting the air in the reactor and the external circulation condenser with nitrogen, add the prepared monoethanolamine and catalyst mixture into the reactor, and then fill the reactor with nitrogen and pressurize it to 0.2MPa; open the external circulation condenser, spray propylene oxide into the reactor, control the reaction temperature to 50-70°C, the pressure to 0.3-0.5Mpa, and the propylene oxide addition time to 120-260min; after the propylene oxide addition is completed, maintain the reaction temperature at 50-70°C, mature the reaction for 30-60min, and cool to obtain monoethanol diisopropanolamine; The reactor is a venturi jet loop reactor; The catalyst is phosphomolybdic acid, silicomolybdic acid, phosphotungstic acid or silicotungstic acid; The molar ratio of propylene oxide to monoethanolamine is (1.98-2.0):1.0; The mass ratio of the catalyst to monoethanolamine is (0.4-0.6):

100.

2. The method for preparing monoethanol diisopropanolamine according to claim 1, characterized in that: The purity of the monoethanolamine is ≥99.5%; the purity of the propylene oxide is ≥99.5%.

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