A method and production equipment for preparing 1,6-hexamethylene-bis(N,N-dimethylaminourea)

Abstract

The application belongs to the technical field of organic synthesis, and provides a preparation method and production equipment of 1,6-hexamethylene-bis(N,N-dimethylamino urea). Hexamethylene diisocyanate and methylhydrazine are gasified, and the hexamethylene diisocyanate gas and the methylhydrazine gas pass through the membrane layer into the reaction solvent to contact and perform nucleophilic addition reaction. The application adjusts the pore diameter of the hexamethylene diisocyanate gas, the methylhydrazine gas and the membrane layer, controls the amount of the hexamethylene diisocyanate gas and the methylhydrazine gas into the reaction solvent, and then controls the speed and process of the nucleophilic addition reaction, so that the nucleophilic addition reaction is more complete. The product is less wrapped around the raw material, the product has less impurities, the problem of sticky material difficult to centrifuge caused by excessive hexamethylene diisocyanate or insufficient methylhydrazine is avoided, the synthesized yellowing inhibitor has high purity, and the yellowing inhibitor purity is greater than or equal to 98.2%.

Description

Technical Field

[0001] This invention relates to the field of organic synthesis technology, and in particular to a method and equipment for preparing 1,6-hexamethylene-bis(N,N-dimethylaminourea). Background Technology

[0002] 1,6-Hexamethylene-bis(N,N-dimethylaminourea) (HN-130), a downstream product of unsymmetrical dimethylhydrazine (UDMH), is an essential auxiliary agent in spandex production. It is used to prevent yellowing of polyurethane and is widely used in the polyurethane industry. Currently used spandex anti-yellowing agents mainly include HN-130 and bis(N,N-dimethylhydrazine amino-4-phenyl)methane (HN-150). The current preparation process for HN-130 typically involves adding a toluene solution of hexamethylene diisocyanate dropwise to a toluene solution of UDMH for a nucleophilic addition reaction. After the reaction, the product is centrifuged to prepare HN-130. The above preparation process has the following disadvantages: it is not easy to control the reaction rate and process by simply adding hexamethylene diisocyanate solution dropwise to unsymmetrical dimethylhydrazine solution, and the reaction is prone to incomplete reaction. If the amount of unsymmetrical dimethylhydrazine is insufficient or the amount of hexamethylene diisocyanate is excessive, viscous material will be produced, making centrifugation difficult and resulting in low purity of the product. Summary of the Invention

[0003] In view of this, the purpose of this invention is to provide a method and equipment for preparing 1,6-hexamethylene-bis(N,N-dimethylaminourea). The 1,6-hexamethylene-bis(N,N-dimethylaminourea) obtained by the preparation method provided by this invention has high purity.

[0004] To achieve the above-mentioned objectives, the present invention provides the following technical solution:

[0005] This invention provides a method for preparing 1,6-hexamethylene-bis(N,N-dimethylaminourea), comprising the following steps:

[0006] Hexamethylene diisocyanate and unsymmetrical dimethylhydrazine were vaporized to obtain hexamethylene diisocyanate gas and unsymmetrical dimethylhydrazine gas, respectively.

[0007] The hexamethylene diisocyanate gas, carried by the first carrier gas, passes through the membrane layer and enters the reaction solvent at a first flow rate;

[0008] The unsymmetrical dimethylhydrazine gas, carried by the second carrier gas, passes through the membrane layer and enters the reaction solvent at a second flow rate;

[0009] The hexamethylene diisocyanate gas and unsymmetrical dimethylhydrazine gas are mixed in a reaction solvent through the membrane layer and undergo a nucleophilic addition reaction to obtain the 1,6-hexamethylene-bis(N,N-dimethylaminourea).

[0010] Preferably, the molar ratio of hexamethylene diisocyanate to unsymmetrical dimethylhydrazine is 1:(2-2.1).

[0011] Preferably, the vaporization temperature of the hexamethylene diisocyanate is 250–270°C, and the vaporization temperature of the unsymmetrical dimethylhydrazine is 60–80°C.

[0012] Preferably, the first carrier gas is nitrogen, the pressure of the first carrier gas is 0.11-0.5 MPa, and the first flow rate is 40-60 mL / min;

[0013] The second carrier gas is nitrogen, the pressure of the second carrier gas is 0.11 to 0.5 MPa, and the second flow rate is 80 to 120 mL / min.

[0014] Preferably, the membrane is made of polytetrafluoroethylene, the thickness of the membrane is 0.5-2 mm, and the pore size of the membrane is 100-300 nm.

[0015] Preferably, the reaction solvent is a polar organic solvent; the polar organic solvent is a haloalkane or ethyl acetate; the water content of the polar organic solvent is <0.1%, and the purity of the polar organic solvent is ≥98%.

[0016] Preferably, the mass ratio of the reaction solvent to unsymmetrical dimethylhydrazine is (8-10):1.

[0017] Preferably, the nucleophilic addition reaction is performed at a temperature of 20–30°C.

[0018] Preferably, after the nucleophilic addition reaction, the process further includes: sequentially incubating the resulting liquid with heat and separating it into solid and liquid phases, collecting the precipitate and drying it.

[0019] The present invention also provides a production apparatus for 1,6-hexamethylene-bis(N,N-dimethylaminourea), comprising:

[0020] Rectangular shell;

[0021] The internal space of the cuboid shell is divided into a first air intake chamber, a reaction chamber, and a second air intake chamber by two partitions in sequence.

[0022] The first and second air inlet chambers are respectively connected to the gasification equipment through air inlet pipes;

[0023] The partition includes a membrane layer and a sand core stacked together;

[0024] The membrane layer in the partition is in contact with the first air intake chamber and the second air intake chamber.

[0025] This invention provides a method for preparing 1,6-hexamethylene-bis(N,N-dimethylaminourea), comprising the following steps: vaporizing hexamethylene diisocyanate and unsymmetrical dimethylhydrazine separately to obtain hexamethylene diisocyanate gas and unsymmetrical dimethylhydrazine gas; the hexamethylene diisocyanate gas, carried by a first carrier gas, passes through a membrane layer at a first flow rate into a reaction solvent; the unsymmetrical dimethylhydrazine gas, carried by a second carrier gas, passes through the membrane layer at a second flow rate into the reaction solvent; the hexamethylene diisocyanate gas and unsymmetrical dimethylhydrazine gas passing through the membrane layer are mixed in the reaction solvent and undergo a nucleophilic addition reaction to obtain 1,6-hexamethylene-bis(N,N-dimethylaminourea).

[0026] This invention involves vaporizing hexamethylene diisocyanate and unsymmetrical dimethylhydrazine (UDMH), then permeating the hexamethylene diisocyanate gas and UDMH gas through a membrane into the reaction solvent, where they contact and undergo a nucleophilic addition reaction. By adjusting the first and second flow rates and the pore size of the membrane, this invention controls the amount of hexamethylene diisocyanate and UDMH gas entering the reaction solvent, thereby controlling the rate and progress of the nucleophilic addition reaction, resulting in a more complete reaction. This avoids product entrainment of the raw materials, resulting in fewer product impurities. It also avoids the problem of excessive hexamethylene diisocyanate or insufficient UDMH causing sticky material that is difficult to centrifuge. The synthesized anti-yellowing agent has high purity, ≥98.2%.

[0027] This invention also provides a production apparatus for 1,6-hexamethylene-bis(N,N-dimethylaminourea), comprising: a cuboid shell; the internal space of the cuboid shell is sequentially divided into a first inlet chamber, a reaction chamber, and a second inlet chamber by two partitions; the first inlet chamber and the second inlet chamber are respectively connected to a gasification device through inlet pipes; the partition includes a layered membrane and a sand core; the membrane in the partition is in contact with the first inlet chamber and the second inlet chamber. The production apparatus provided by this invention is simple and effectively improves the purity of 1,6-hexamethylene-bis(N,N-dimethylaminourea). Attached Figure Description

[0028] Figure 1 A schematic diagram of the structure of the production equipment provided by the present invention;

[0029] Figure 2 A 3D schematic diagram of the production equipment provided by the present invention;

[0030] Figure 1 and Figure 2 1. Gasification equipment, 2. Inlet pipe, 3. Flow meter, 4. Membrane layer, 5. Sand core, 6. Rectangular shell, 7. Reaction chamber, 8. First inlet chamber, 9. Stirring device, 10. Reaction chamber opening, 11. Second inlet chamber, 12. Baffle. Detailed Implementation

[0031] This invention provides a method for preparing 1,6-hexamethylene-bis(N,N-dimethylaminourea), comprising the following steps:

[0032] Hexamethylene diisocyanate and unsymmetrical dimethylhydrazine were vaporized to obtain hexamethylene diisocyanate gas and unsymmetrical dimethylhydrazine gas, respectively.

[0033] The hexamethylene diisocyanate gas, carried by the first carrier gas, passes through the membrane layer and enters the reaction solvent at a first flow rate;

[0034] The unsymmetrical dimethylhydrazine gas, carried by the second carrier gas, passes through the membrane layer and enters the reaction solvent at a second flow rate;

[0035] The hexamethylene diisocyanate gas and unsymmetrical dimethylhydrazine gas are mixed in a reaction solvent through the membrane layer and undergo a nucleophilic addition reaction to obtain the 1,6-hexamethylene-bis(N,N-dimethylaminourea).

[0036] Unless otherwise specified, all materials used in this invention are preferably commercially available products.

[0037] In this invention, hexamethylene diisocyanate and unsymmetrical dimethylhydrazine are vaporized separately to obtain hexamethylene diisocyanate gas and unsymmetrical dimethylhydrazine gas.

[0038] In this invention, the molar ratio of hexamethylene diisocyanate gas and unsymmetrical dimethylhydrazine gas is preferably 1:(2 to 2.1).

[0039] In this invention, the vaporization temperature of the hexamethylene diisocyanate is preferably 250–270°C. In this invention, the vaporization temperature of the unsymmetrical dimethylhydrazine is preferably 60–80°C.

[0040] After obtaining hexamethylene diisocyanate gas, the hexamethylene diisocyanate gas of the present invention, carried by a first carrier gas, passes through the membrane layer and enters the reaction solvent at a first flow rate.

[0041] In this invention, the first carrier gas is preferably nitrogen. The pressure of the first carrier gas is preferably 0.11–0.5 MPa. The first flow rate is preferably 40–60 mL / min.

[0042] After obtaining unsymmetrical dimethylhydrazine gas, the unsymmetrical dimethylhydrazine gas of the present invention, carried by a second carrier gas, passes through the membrane layer and enters the reaction solvent at a second flow rate.

[0043] In this invention, the second carrier gas is preferably nitrogen, and the pressure of the second carrier gas is preferably 0.11–0.5 MPa. In this invention, the second flow rate is preferably 80–120 mL / min.

[0044] The present invention obtains 1,6-hexamethylene-bis(N,N-dimethylaminourea) by mixing the hexamethylene diisocyanate gas and unsymmetrical dimethylhydrazine gas in a reaction solvent and carrying out a nucleophilic addition reaction.

[0045] In this invention, the membrane layer is preferably made of polytetrafluoroethylene. The membrane layer thickness is preferably 0.5–2 mm. The membrane layer pore size is preferably 100–300 nm.

[0046] In this invention, the reaction solvent is preferably a polar organic solvent; the polar organic solvent is preferably a haloalkane or ethyl acetate, more preferably ethyl acetate. In this invention, the water content of the polar organic solvent is preferably <0.1%. In this invention, the purity of the polar organic solvent is preferably ≥98%.

[0047] In this invention, the mass ratio of the reaction solvent to unsymmetrical dimethylhydrazine is preferably (8-10):1, and more preferably 9:1.

[0048] In this invention, the temperature of the nucleophilic addition reaction is preferably 20–30°C. The time for the nucleophilic addition reaction is not specifically limited, as long as the hexamethylene diisocyanate and unsymmetrical dimethylhydrazine react completely. In this invention, the nucleophilic addition reaction is preferably carried out under stirring conditions; the stirring speed is preferably 100–120 r / min.

[0049] After the nucleophilic addition reaction, the present invention preferably further includes: sequentially incubating the obtained liquid and separating it into solid and liquid phases, collecting the precipitate and drying it.

[0050] In this invention, the holding temperature is preferably the same as the temperature of the nucleophilic addition reaction, which will not be elaborated further here; the holding time is preferably 0.5 to 1 hour. In this invention, the solid-liquid separation method is preferably centrifugation, the centrifugation speed is preferably 1000 to 1500 rpm, and the time is preferably 5 to 10 minutes. In this invention, the drying method is preferably vacuum drying, the vacuum drying temperature is preferably 75 to 85°C, the pressure is preferably ≤ -0.08 MPa, and the time is preferably 9 to 10 hours.

[0051] The present invention also provides a production apparatus for 1,6-hexamethylene-bis(N,N-dimethylaminourea), comprising:

[0052] Rectangular shell;

[0053] The internal space of the cuboid shell is divided into a first air intake chamber, a reaction chamber, and a second air intake chamber by two partitions in sequence.

[0054] The first and second air inlet chambers are respectively connected to the gasification equipment through air inlet pipes;

[0055] The partition includes a membrane layer and a sand core stacked together;

[0056] The membrane layer in the partition is in contact with the first air intake chamber and the second air intake chamber.

[0057] Figure 1 A schematic diagram of the structure of the production equipment provided by the present invention; Figure 2 This is a 3D schematic diagram of the production equipment provided by the present invention; the following is in conjunction with... Figure 1 and Figure 2 The structure of the production equipment provided by the present invention is described.

[0058] The production equipment for 1,6-hexamethylene-bis(N,N-dimethylaminourea) provided by the present invention includes a cuboid shell 6, which is preferably made of stainless steel.

[0059] In this invention, the internal space of the cuboid shell 6 is divided into a first air intake chamber 8, a reaction chamber 7, and a second air intake chamber 11 by two partitions 12.

[0060] In this invention, the first air inlet chamber 8 and the second air inlet chamber 11 are respectively connected to the gasification device 1 via air inlet pipes 2. Preferably, a flow meter 3 is installed on the air inlet pipe 2.

[0061] In this invention, the partition 12 comprises a membrane layer 4 and a sand core 5 stacked together; the membrane layer 4 is preferably made of polytetrafluoroethylene; the thickness of the membrane layer 4 is preferably 0.5–2 mm; and the pore size of the membrane layer 4 is preferably 100–300 nm. In this invention, the pore size of the sand core 5 is preferably 1–1.5 μm; and the thickness of the sand core 5 is preferably 10–15 mm. In this invention, the sand core provides support for the membrane layer, extending its service life.

[0062] In this invention, the membrane layer 4 in the partition 12 is in contact with the first air intake chamber 8 and the second air intake chamber 11.

[0063] In this invention, the reaction chamber 7 is preferably equipped with a stirring device 9.

[0064] In this invention, the reaction chamber 7 is provided with a reaction chamber opening 10.

[0065] The following detailed description of the preparation method and production equipment of 1,6-hexamethylene-bis(N,N-dimethylaminourea) provided by the present invention, with reference to the embodiments, should not be construed as limiting the scope of protection of the present invention.

[0066] Example 1

[0067] exist Figure 1 The preparation of 1,6-hexamethylene-bis(N,N-dimethylaminourea) in the production equipment shown includes the following steps:

[0068] Accurately weigh 70g of hexamethylene diisocyanate and add it to the gasification device. Heat it to 260℃ to vaporize it and obtain hexamethylene diisocyanate gas.

[0069] Accurately weigh 50g of unsymmetrical dimethylhydrazine (mass percentage ≥98.5%) and add it to the gasification equipment. Heat it to 70℃ to vaporize it and obtain unsymmetrical dimethylhydrazine gas.

[0070] 500 mL of ethyl acetate was added to the reaction chamber. Hexamethylene diisocyanate gas, carried by nitrogen gas at a pressure of 0.3 MPa, entered the first inlet chamber at a flow rate of 40 mL / min. Unsymmetrical dimethylhydrazine gas, carried by nitrogen gas at a pressure of 0.3 MPa, entered the second inlet chamber at a flow rate of 90 mL / min. The hexamethylene diisocyanate gas in the first inlet chamber and the unsymmetrical dimethylhydrazine gas in the second inlet chamber entered the ethyl acetate through a polytetrafluoroethylene membrane (1.5 mm thick, 200 nm pore size) and a sintered metal core (10 mm thick, 1 μm pore size), respectively. The nucleophilic addition reaction was carried out in the ethyl acetate at 20 °C until the hexamethylene diisocyanate and unsymmetrical dimethylhydrazine reacted completely. During the nucleophilic addition reaction, the stirring speed of the ethyl acetate was controlled at 100 r / min. The reaction was then maintained at 20 °C for 0.5 h to obtain the reaction solution.

[0071] The reaction solution was centrifuged for 10 minutes at a speed of 1300 rpm. The solid product obtained by centrifugation was dried in a vacuum dryer at a pressure ≤ -0.08 MPa, a drying temperature of 80℃, and a drying time of 10 hours to obtain a powdery white product with a purity of 99.3%.

[0072] Example 2

[0073] exist Figure 1 The preparation of 1,6-hexamethylene-bis(N,N-dimethylaminourea) in the production equipment shown includes the following steps:

[0074] Accurately weigh 70g of hexamethylene diisocyanate and add it to the gasification device. Heat it to 260℃ to vaporize it and obtain hexamethylene diisocyanate gas.

[0075] Accurately weigh 50g of unsymmetrical dimethylhydrazine (mass percentage ≥98.5%) and add it to the gasification equipment. Heat it to 70℃ to vaporize it and obtain unsymmetrical dimethylhydrazine gas.

[0076] 500 mL of ethyl acetate was added to the reaction chamber. Hexamethylene diisocyanate gas, carried by nitrogen gas at a pressure of 0.3 MPa, entered the first inlet chamber at a flow rate of 60 mL / min. Unsymmetrical dimethylhydrazine gas, carried by nitrogen gas at a pressure of 0.3 MPa, entered the second inlet chamber at a flow rate of 120 mL / min. The hexamethylene diisocyanate gas in the first inlet chamber and the unsymmetrical dimethylhydrazine gas in the second inlet chamber entered the ethyl acetate through a polytetrafluoroethylene membrane (1.5 mm thick, 200 nm pore size) and a sintered metal core (10 mm thick, 1 μm pore size), respectively. The nucleophilic addition reaction was carried out in the ethyl acetate at 20 °C until the hexamethylene diisocyanate and unsymmetrical dimethylhydrazine reacted completely. During the nucleophilic addition reaction, the stirring speed of the ethyl acetate was controlled at 100 r / min. The reaction was then maintained at 20 °C for 0.5 h to obtain the reaction solution.

[0077] After the reaction was completed, the reaction solution was centrifuged for 10 minutes at a speed of 1300 rpm. The solid product obtained by centrifugation was dried in a vacuum dryer at a pressure ≤ -0.08 MPa, a drying temperature of 80℃, and a drying time of 10 hours to obtain a powdery white product with a purity of 98.7%.

[0078] Example 3

[0079] exist Figure 1 The preparation of 1,6-hexamethylene-bis(N,N-dimethylaminourea) in the production equipment shown includes the following steps:

[0080] Accurately weigh 70g of hexamethylene diisocyanate and add it to the gasification device. Heat it to 260℃ to vaporize it and obtain hexamethylene diisocyanate gas.

[0081] Accurately weigh 50g of unsymmetrical dimethylhydrazine (mass percentage ≥98.5%) and add it to the gasification equipment. Heat it to 70℃ to vaporize it and obtain unsymmetrical dimethylhydrazine gas.

[0082] 500 mL of ethyl acetate was added to the reaction chamber. Hexamethylene diisocyanate gas, carried by nitrogen gas at a pressure of 0.3 MPa, entered the first inlet chamber at a flow rate of 40 mL / min. Unsymmetrical dimethylhydrazine gas, carried by nitrogen gas at a pressure of 0.3 MPa, entered the second inlet chamber at a flow rate of 90 mL / min. The hexamethylene diisocyanate gas in the first inlet chamber and the unsymmetrical dimethylhydrazine gas in the second inlet chamber entered the ethyl acetate through a polytetrafluoroethylene membrane (1.5 mm thick, 300 nm pore size) and a sintered metal core (10 mm thick, 1 μm pore size), respectively. The nucleophilic addition reaction was carried out in the ethyl acetate at 20 °C until the hexamethylene diisocyanate and unsymmetrical dimethylhydrazine reacted completely. During the nucleophilic addition reaction, the stirring speed of the ethyl acetate was controlled at 100 r / min. The reaction was then maintained at 20 °C for 0.5 h to obtain the reaction solution.

[0083] After the reaction was completed, the reaction solution was centrifuged for 10 minutes at a speed of 1300 rpm. The solid product obtained by centrifugation was dried in a vacuum dryer at a pressure ≤ -0.08 MPa, a drying temperature of 80℃, and a drying time of 10 hours to obtain a powdery white product with a purity of 98.2%.

[0084] Comparative Example 1

[0085] Accurately weigh 70g of hexamethylene diisocyanate and add it to 220mL of ethyl acetate. Stir to mix thoroughly to obtain a hexamethylene diisocyanate solution.

[0086] Accurately weigh 50g of unsymmetrical dimethylhydrazine and add it to 280mL of ethyl acetate. Stir to mix thoroughly to obtain an unsymmetrical dimethylhydrazine solution.

[0087] Hexamethylene diisocyanate was dissolved and added dropwise to unsymmetrical dimethylhydrazine solution to carry out a nucleophilic addition reaction. The stirring speed was controlled at 100 r / min. After the reaction was completed, the mixture was kept at 20 °C for 0.5 h to continue the reaction and obtain the reaction solution.

[0088] After the reaction was completed, the reaction solution was centrifuged for 10 minutes at a speed of 1300 rpm. The solid product obtained by centrifugation was dried in a vacuum dryer at a pressure ≤ -0.08 MPa, a drying temperature of 80℃, and a drying time of 10 hours to obtain a powdery white product with a purity of 93.1%.

[0089] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A process for the preparation of 1,6-hexamethylene-bis(N,N-dimethyl- hydrazinecarboxamide) characterized in that, Preparation of 1,6-hexamethylene-bis(N,N-dimethylhydrazinecarboxamide) in a production device, The production device comprises: a cuboid shell; an internal space of the cuboid shell is divided into a first gas inlet chamber, a reaction chamber and a second gas inlet chamber in sequence by two partitions; the first gas inlet chamber and the second gas inlet chamber are respectively communicated with a gasification device through gas inlet pipelines; the partitions comprise membrane layers and sand cores arranged in layers; the membrane layers in the partitions are in contact with the first gas inlet chamber and the second gas inlet chamber; comprising the following steps: precisely weighing 70 g of hexamethylene diisocyanate into the gasification device, heating to 260 ℃ to make it gasify, and obtaining hexamethylene diisocyanate gas; precisely weighing 50 g of methylhydrazine into the gasification device, heating to 70 ℃ to make it gasify, and obtaining methylhydrazine gas; the mass percentage content of the methylhydrazine is ≥98.5%; adding 500 mL of ethyl acetate into the reaction chamber, and making the hexamethylene diisocyanate gas carried by nitrogen gas at a pressure of 0.3 MPa enter the first gas inlet chamber at a flow rate of 40 mL / min; making the methylhydrazine gas carried by nitrogen gas at a pressure of 0.3 MPa enter the second gas inlet chamber at a flow rate of 90 mL / min; the hexamethylene diisocyanate gas in the first gas inlet chamber and the methylhydrazine gas in the second gas inlet chamber respectively enter the ethyl acetate through a polytetrafluoroethylene membrane and a sand core, and a nucleophilic addition reaction is carried out in the ethyl acetate at 20 ℃ until the hexamethylene diisocyanate and the methylhydrazine react completely, and the stirring speed of the ethyl acetate is controlled to be 100 r / min during the nucleophilic addition reaction; continuing to incubate at 20 ℃ for 0.5 h, and obtaining a reaction liquid; the thickness of the polytetrafluoroethylene membrane is 1.5 mm, the pore size is 200 nm, the thickness of the sand core is 10 mm, and the pore size is 1 μm; centrifuging the reaction liquid, the centrifugation time is 10 min, and the centrifugation speed is 1300 r / min; drying the solid product obtained by centrifugation in a vacuum drying machine, the pressure is ≤-0.08 MPa, the drying temperature is 80 ℃, and the drying time is 10 h, and obtaining a white powder product.

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