A kind of preparation method of isopropanolamine

Abstract

The invention belongs to the technical field of isopropanolamine preparation, and specifically is a method for preparing isopropanolamine, comprising: S100: mixing propylene oxide and liquid ammonia in a molar ratio of (5-30):1 to obtain a first mixed material; S200: catalyzing the first mixed material through a zeolite catalyst to obtain an isopropanolamine mixed material; wherein the weight ratio of aluminum to silicon in the zeolite catalyst is 0.8-2 or 50-150. The preparation cost of isopropanolamine can be reduced, the process is simple, the energy consumption is low, and isopropanolamine can be efficiently prepared.

Description

Technical Field

[0001] The invention belongs to the technical field of isopropanolamine preparation, and specifically relates to a method for preparing isopropanolamine. Background Art

[0002] Isopropanolamine is divided into three types: monoisopropanolamine, diisopropanolamine and triisopropanolamine, and all of them have a wide range of applications. Monoisopropanolamine is mainly used in surfactants, metalworking fluids, paints and coatings, textile printing and dyeing, personal care products, water treatment agents and pharmaceutical pesticide intermediates; diisopropanolamine is mainly used in natural gas and refinery gas to remove hydrogen sulfide and carbon dioxide, as well as fiber additives, tanning agents, pesticides and cutting oils; triisopropanolamine is mainly used as a cement grinding aid and a crosslinking agent and additive for rubber, plastics and polyurethane processing.

[0003] In the prior art, the preparation methods of isopropanolamine include the calcium cyanamide method and the propylene oxide method. The calcium cyanamide method uses propylene oxide and calcium cyanamide as the main raw materials, and produces calcium carbonate and 2-amino-3-(2-hydroxypropyl)-5-methyl-1,3-dioxazolidine through reaction, and finally reacts with potassium hydroxide to produce isopropanolamine; the propylene oxide method uses ammonia and propylene oxide as raw materials, and produces isopropanolamine through the steps of ring opening reaction, dehydrogenation, distillation, etc. At present, the propylene oxide method is the mainstream method for industrial production of isopropanolamine.

[0004] The reaction of preparing isopropanolamine by the propylene oxide method is a three-stage cascade reaction. Under any ratio of ammonia to propylene oxide, three products, namely monoisopropanolamine, diisopropanolamine and triisopropanolamine, will be generated. It is impossible to prepare a single monoisopropanolamine, diisopropanolamine or triisopropanolamine. However, the higher the ammonia content, the higher the production rate of monoisopropanolamine.

[0005] Moreover, water is often used as a catalyst in the propylene oxide process. Many factories use high-concentration ammonia water for the reaction, but the dehydration process after the reaction consumes too much energy and does not meet the requirements of green environmental protection. In order to solve this problem, some factories prepare special catalysts to avoid the dehydration step, but the cost of the catalysts used is high and the preparation process is complicated, which not only fails to reduce the overall production cost, but also increases the complexity of the process. Summary of the invention

[0006] The invention provides a method for preparing isopropanolamine, which can reduce the preparation cost of isopropanolamine, has a simple process, consumes less energy, and can efficiently prepare isopropanolamine.

[0007] In order to solve the above technical problems, the technical solution adopted by the present invention is: a method for preparing isopropanolamine, comprising:

[0008] S100: mixing propylene oxide and liquid ammonia in a molar ratio of (5-30):1 to obtain a first mixed material;

[0009] S200: catalyzing the first mixed material with a zeolite catalyst to obtain an isopropanolamine mixed material;

[0010] Wherein, the weight ratio of aluminum to silicon in the zeolite catalyst is 0.8-2 or 50-150.

[0011] Furthermore, the zeolite catalyst is at least one of type A molecular sieve and ZSM-5 molecular sieve.

[0012] Furthermore, the type A molecular sieve is at least one of type 3A molecular sieve and type 4A molecular sieve, and the water absorption of the type A molecular sieve is 80 mg / g-130 mg / g.

[0013] Furthermore, when 3A type molecular sieve is selected, S100 is a mixture of propylene oxide and liquid ammonia in a molar ratio of (20-30):1.

[0014] Furthermore, when 4A type molecular sieve is selected, S100 is a mixture of propylene oxide and liquid ammonia in a molar ratio of (15-25):1.

[0015] Furthermore, when ZSM-5 molecular sieve is selected, S100 is obtained by mixing propylene oxide and liquid ammonia in a molar ratio of (5-15):1.

[0016] Furthermore, S100 specifically includes the following steps:

[0017] Propylene oxide is preheated to 75°C-95°C, and liquid ammonia is heated to 75°C-95°C, respectively, and then introduced into a mixer for mixing and heating to 90°C-100°C to obtain a first mixed material.

[0018] Furthermore, S200 specifically includes the following steps:

[0019] The first mixed material is introduced into a fixed bed reactor equipped with a zeolite catalyst, and the reaction temperature is controlled to be 100° C.-130° C., the reaction pressure is 10 MPa-15 MPa, and the reaction time is 2 h-5 h to obtain an isopropanolamine mixed material.

[0020] Furthermore, the isopropanolamine mixture contains 88%-95% of monoisopropanolamine.

[0021] Furthermore, before the first mixed material is introduced into the fixed bed reactor, ammonia gas is introduced into the fixed bed reactor for 3 min to 7 min.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] (1) The present invention has simple process, reduced energy consumption, low cost, and still high production rate of monoisopropanolamine;

[0024] (2) The present invention uses type A molecular sieve to adsorb water molecules as a catalyst, which can not only reduce the subsequent dehydration process, but also save the cost of the catalyst;

[0025] (3) The present invention uses ZSM-5 molecular sieve as a catalyst, which can effectively promote the formation of monoisopropanolamine and improve the preparation efficiency. DETAILED DESCRIPTION

[0026] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, specific embodiments of the present invention are described in detail below.

[0027] The present invention provides a method for preparing isopropanolamine, comprising:

[0028] S100: mixing propylene oxide and liquid ammonia in a molar ratio of (5-30):1 to obtain a first mixed material;

[0029] S200: catalyzing the first mixed material with a zeolite catalyst to obtain an isopropanolamine mixed material;

[0030] Wherein, the weight ratio of aluminum to silicon in the zeolite catalyst is 0.8-2 or 50-150.

[0031] In the present invention, the zeolite catalyst is at least one of type A molecular sieve and ZSM-5 molecular sieve. Preferably, type A molecular sieve is at least one of type 3A molecular sieve and type 4A molecular sieve, and the water absorption of type A molecular sieve is 80mg / g-130mg / g when used. Wherein, when type A molecular sieve is selected as the catalyst, the aluminum-silicon weight ratio is controlled at 1-1.2. The above zeolite catalysts are all commercial products and can be purchased on the market.

[0032] In one embodiment of the present invention, 3A molecular sieve is selected as the catalyst, and S100 is to mix propylene oxide and liquid ammonia at a molar ratio of (20-30): 1. Preferably, propylene oxide and liquid ammonia are mixed at a molar ratio of (21-23): 1. More preferably, propylene oxide and liquid ammonia are mixed at a molar ratio of 22: 1.

[0033] In one embodiment of the present invention, 4A molecular sieve is selected as the catalyst, and S100 is to mix propylene oxide and liquid ammonia in a molar ratio of (15-25): 1. Preferably, propylene oxide and liquid ammonia are mixed in a molar ratio of (17-19): 1. More preferably, propylene oxide and liquid ammonia are mixed in a molar ratio of 18: 1.

[0034] In one embodiment of the present invention, ZSM-5 molecular sieve is used as a catalyst, and S100 is to mix propylene oxide and liquid ammonia in a molar ratio of (5-15):1. Preferably, propylene oxide and liquid ammonia are mixed in a molar ratio of (8-10):1. More preferably, propylene oxide and liquid ammonia are mixed in a molar ratio of 9:1. When ZSM-5 molecular sieve is used as a catalyst, the weight ratio of aluminum to silicon is controlled to be 90-130.

[0035] In one embodiment of the present invention, 3A molecular sieve and ZSM-5 molecular sieve in a mass ratio of 8:2 are selected as catalysts, and S100 is a mixture of propylene oxide and liquid ammonia in a molar ratio of 12:1.

[0036] Among them, the above-mentioned ZSM-5 molecular sieve can be selected as a copper-doped ZSM-5 molecular sieve as a catalyst. For ease of understanding, the present application provides a method for preparing a copper-doped ZSM-5 molecular sieve: ZSM-5 molecular sieve, copper chloride, and deionized water with a mass ratio of 1:0.07:40 are mixed, wherein the aluminum-silicon weight ratio of the ZSM-5 molecular sieve is 90-130, and then stirred continuously for 2 hours at a temperature of 65°C, and then the pH is adjusted to 7.5 with ammonia water, and aluminum chloride solution is added dropwise. After stirring for 30 minutes, it is allowed to stand for 2 hours, washed with deionized water, dried, and heated at a temperature of 150°C for 1 hour to obtain a copper-doped ZSM-5 molecular sieve.

[0037] In the present invention, S100 specifically includes the following steps: preheating propylene oxide to 75°C-95°C, heating liquid ammonia to 75°C-95°C, respectively, and then passing them into a mixer for mixing and heating to 90°C-100°C to obtain a first mixed material. Preferably, preheating propylene oxide to 80°C, heating liquid ammonia to 75°C, respectively, and then passing them into a mixer for mixing and heating to 95°C to obtain a first mixed material.

[0038] Wherein, a plate heat exchanger is used to preheat propylene oxide and liquid ammonia respectively, and a static mixer is used as a mixer.

[0039] In the present invention, S200 specifically includes the following steps: passing the first mixed material into a fixed bed reactor equipped with a zeolite catalyst, and controlling the reaction temperature to 100° C.-130° C., the reaction pressure to 10 MPa-15 MPa, and the reaction time to 2 h-5 h to obtain an isopropanolamine mixed material.

[0040] Preferably, S200 specifically includes the following steps: passing the first mixed material into a fixed bed reactor equipped with a zeolite catalyst, and controlling the reaction temperature to 120° C., the reaction pressure to 11 MPa, and the reaction time to 3 h to obtain an isopropanolamine mixed material.

[0041] In the present invention, the prepared isopropanolamine mixture is a mixture of monoisopropanolamine, diisopropanolamine and triisopropanolamine, but the prepared isopropanolamine mixture contains 88%-95% of monoisopropanolamine by mass.

[0042] In the present invention, in order to remove free water molecules, before the first mixed material is introduced into the fixed bed reactor, ammonia gas is first introduced into the fixed bed reactor for 3 min to 7 min.

[0043] Embodiment 1

[0044] A method for preparing isopropanolamine comprises: spraying deionized water on a 3A molecular sieve until the water absorption of the 3A molecular sieve is 100 mg / g, then loading the 3A molecular sieve into a fixed bed reactor, and then using a plate heat exchanger to preheat propylene oxide to 80°C and liquid ammonia to 75°C, respectively, and then passing propylene oxide and liquid ammonia with a molar ratio of 22:1 into a mixer, mixing and heating to 95°C to obtain a first mixture; passing ammonia gas into the fixed bed reactor for 5 minutes, passing the first mixture into the fixed bed reactor, and controlling the reaction temperature to 120°C, the reaction pressure to 11 MPa, and the reaction time to 3 hours to obtain an isopropanolamine mixture. After testing, the isopropanolamine mixture contains 89.4% monoisopropanolamine by mass.

[0045] Embodiment 2

[0046] A method for preparing isopropanolamine comprises: spraying deionized water on a 3A molecular sieve until the water absorption of the 3A molecular sieve is 80 mg / g, then loading the 3A molecular sieve into a fixed bed reactor, and then using a plate heat exchanger to preheat propylene oxide to 80°C and liquid ammonia to 75°C, respectively, and then passing propylene oxide and liquid ammonia with a molar ratio of 22:1 into a mixer, mixing and heating to 95°C to obtain a first mixture; passing ammonia gas into the fixed bed reactor for 5 minutes, passing the first mixture into the fixed bed reactor, and controlling the reaction temperature to 120°C, the reaction pressure to 11 MPa, and the reaction time to 3 hours to obtain an isopropanolamine mixture. After testing, the isopropanolamine mixture contains 88.2% monoisopropanolamine by mass.

[0047] Embodiment 3

[0048] A method for preparing isopropanolamine comprises: spraying deionized water on a 3A molecular sieve until the water absorption of the 3A molecular sieve is 90 mg / g, then loading the 3A molecular sieve into a fixed bed reactor, and then using a plate heat exchanger to preheat propylene oxide to 80°C and liquid ammonia to 75°C, respectively, and then passing propylene oxide and liquid ammonia with a molar ratio of 22:1 into a mixer, mixing and heating to 95°C to obtain a first mixture; passing ammonia gas into the fixed bed reactor for 5 minutes, passing the first mixture into the fixed bed reactor, and controlling the reaction temperature to 120°C, the reaction pressure to 11 MPa, and the reaction time to 3 hours to obtain an isopropanolamine mixture. After testing, the isopropanolamine mixture contains 88.7% monoisopropanolamine by mass.

[0049] Embodiment 4

[0050] A method for preparing isopropanolamine comprises: spraying deionized water on a 3A molecular sieve until the water absorption of the 3A molecular sieve is 110 mg / g, then loading the 3A molecular sieve into a fixed bed reactor, and then using a plate heat exchanger to preheat propylene oxide to 80°C and liquid ammonia to 75°C, respectively, and then passing propylene oxide and liquid ammonia with a molar ratio of 22:1 into a mixer, mixing and heating to 95°C to obtain a first mixture; passing ammonia gas into the fixed bed reactor for 5 minutes, passing the first mixture into the fixed bed reactor, and controlling the reaction temperature to 120°C, the reaction pressure to 11 MPa, and the reaction time to 3 hours to obtain an isopropanolamine mixture. After testing, the isopropanolamine mixture contains 88.8% monoisopropanolamine by mass.

[0051] Embodiment 5

[0052] A method for preparing isopropanolamine comprises: spraying deionized water on a 3A molecular sieve until the water absorption of the 3A molecular sieve is 120 mg / g, then loading the 3A molecular sieve into a fixed bed reactor, and then using a plate heat exchanger to preheat propylene oxide to 80°C and liquid ammonia to 75°C, respectively, and then passing propylene oxide and liquid ammonia with a molar ratio of 22:1 into a mixer, mixing and heating to 95°C to obtain a first mixture; passing ammonia gas into the fixed bed reactor for 5 minutes, passing the first mixture into the fixed bed reactor, and controlling the reaction temperature to 120°C, the reaction pressure to 11 MPa, and the reaction time to 3 hours to obtain an isopropanolamine mixture. After testing, the isopropanolamine mixture contains 89.1% monoisopropanolamine by mass.

[0053] It can be seen from the experimental data of Examples 1 to 5 that when 3A molecular sieve is used, controlling the water absorption of 3A molecular sieve to 100 mg / g has better monoisopropanolamine selectivity.

[0054] Embodiment 6

[0055] A method for preparing isopropanolamine comprises: spraying deionized water on a 4A molecular sieve until the water absorption of the 4A molecular sieve is 100 mg / g, then loading the 4A molecular sieve into a fixed bed reactor, and then preheating propylene oxide to 80°C and liquid ammonia to 75°C using a plate heat exchanger, then introducing propylene oxide and liquid ammonia in a molar ratio of 22:1 into a mixer, mixing and heating to 95°C to obtain a first mixture; introducing ammonia gas into the fixed bed reactor for 5 minutes, introducing the first mixture into the fixed bed reactor, and controlling the reaction temperature to 120°C, the reaction pressure to 11 MPa, and the reaction time to 3 hours to obtain an isopropanolamine mixture. After testing, the isopropanolamine mixture contains 88.5% monoisopropanolamine by mass.

[0056] By comparing Example 1 with Example 6, it can be seen that when the water absorption is controlled at 100 mg / g and the molar ratio of propylene oxide to liquid ammonia is 22:1, the 3A molecular sieve has better monoisopropanolamine selectivity.

[0057] Embodiment 7

[0058] A method for preparing isopropanolamine comprises: spraying deionized water on a 4A molecular sieve until the water absorption of the 4A molecular sieve is 100 mg / g, then loading the 4A molecular sieve into a fixed bed reactor, and then using a plate heat exchanger to preheat propylene oxide to 80°C and liquid ammonia to 75°C, respectively, and then passing propylene oxide and liquid ammonia in a molar ratio of 18:1 into a mixer, mixing and heating to 95°C to obtain a first mixture; passing ammonia gas into the fixed bed reactor for 5 minutes, passing the first mixture into the fixed bed reactor, and controlling the reaction temperature to 120°C, the reaction pressure to 11 MPa, and the reaction time to 3 hours to obtain an isopropanolamine mixture. After testing, the isopropanolamine mixture contains 89.7% monoisopropanolamine by mass.

[0059] By comparing the first embodiment, the sixth embodiment and the seventh embodiment, it can be seen that the 4A molecular sieve has better monoisopropanolamine selectivity under the condition that the molar ratio of propylene oxide to liquid ammonia is 18:1.

[0060] Embodiment 8

[0061] A method for preparing isopropanolamine comprises: spraying deionized water on a 4A molecular sieve until the water absorption of the 4A molecular sieve is 105 mg / g, then loading the 4A molecular sieve into a fixed bed reactor, and then preheating propylene oxide to 80°C and liquid ammonia to 75°C using a plate heat exchanger, then introducing propylene oxide and liquid ammonia in a molar ratio of 18:1 into a mixer, mixing and heating to 95°C to obtain a first mixture; introducing ammonia gas into the fixed bed reactor for 5 minutes, introducing the first mixture into the fixed bed reactor, and controlling the reaction temperature to 120°C, the reaction pressure to 11 MPa, and the reaction time to 3 hours to obtain an isopropanolamine mixture. After testing, the isopropanolamine mixture contains 90.4% monoisopropanolamine by mass.

[0062] Embodiment 9

[0063] A method for preparing isopropanolamine comprises: spraying deionized water on a 4A molecular sieve until the water absorption of the 4A molecular sieve is 110 mg / g, then loading the 4A molecular sieve into a fixed bed reactor, and then using a plate heat exchanger to preheat propylene oxide to 80°C and liquid ammonia to 75°C, respectively, and then passing propylene oxide and liquid ammonia in a molar ratio of 18:1 into a mixer, mixing and heating to 95°C to obtain a first mixture; passing ammonia gas into the fixed bed reactor for 5 minutes, passing the first mixture into the fixed bed reactor, and controlling the reaction temperature to 120°C, the reaction pressure to 11 MPa, and the reaction time to 3 hours to obtain an isopropanolamine mixture. After testing, the isopropanolamine mixture contains 89.2% monoisopropanolamine by mass.

[0064] By comparing Example 1 and Example 6 to Example 9, it can be seen that when the water absorption of the 4A molecular sieve is controlled to be 105 mg / g, it has better monoisopropanolamine selectivity, and generally the 4A molecular sieve has a better catalytic effect than the 3A molecular sieve.

[0065] Embodiment 10

[0066] A method for preparing isopropanolamine comprises: spraying deionized water on a ZSM-5 molecular sieve until the water absorption of the ZSM-5 molecular sieve is saturated, then loading the ZSM-5 molecular sieve into a fixed bed reactor, and then preheating propylene oxide to 80°C and liquid ammonia to 75°C using a plate heat exchanger, then introducing propylene oxide and liquid ammonia in a molar ratio of 18:1 into a mixer, mixing and heating to 95°C to obtain a first mixture; introducing ammonia gas into the fixed bed reactor for 5 minutes, introducing the first mixture into the fixed bed reactor, and controlling the reaction temperature to 120°C, the reaction pressure to 11MPa, and the reaction time to 3h to obtain an isopropanolamine mixture. After testing, the isopropanolamine mixture contains 84.3% monoisopropanolamine by mass.

[0067] By comparing Example 10 with Example 8, it can be seen that the 4A molecular sieve has a better catalytic effect than the ZSM-5 molecular sieve.

[0068] Embodiment 11

[0069] A method for preparing isopropanolamine comprises: spraying deionized water on a ZSM-5 molecular sieve until the water absorption of the ZSM-5 molecular sieve is saturated, then loading the ZSM-5 molecular sieve into a fixed bed reactor, and then using a plate heat exchanger to preheat propylene oxide to 80°C and liquid ammonia to 75°C, respectively, and then passing propylene oxide and liquid ammonia in a molar ratio of 9:1 into a mixer, mixing and heating to 95°C to obtain a first mixture; passing ammonia gas into the fixed bed reactor for 5 minutes, passing the first mixture into the fixed bed reactor, and controlling the reaction temperature to 120°C, the reaction pressure to 11MPa, and the reaction time to 3h to obtain an isopropanolamine mixture. After testing, the isopropanolamine mixture contains 85.1% monoisopropanolamine by mass.

[0070] By comparing Example 10 with Example 11, it can be seen that the ZSM-5 molecular sieve has better monoisopropanolamine selectivity under the condition that the molar ratio of propylene oxide to liquid ammonia is 18:1.

[0071] Embodiment 12

[0072] A method for preparing isopropanolamine comprises: spraying deionized water onto a 3A molecular sieve until the water absorption of the 3A molecular sieve is 100 mg / g, spraying deionized water onto a ZSM-5 molecular sieve until the water absorption of the ZSM-5 molecular sieve is saturated, mixing the 3A molecular sieve and the ZSM-5 molecular sieve in a mass ratio of 8:2, loading the mixed catalyst into a fixed bed reactor, preheating propylene oxide to 80°C and heating liquid ammonia to 75°C respectively using a plate heat exchanger, then introducing propylene oxide and liquid ammonia in a molar ratio of 18:1 into a mixer, mixing and heating to 95°C to obtain a first mixed material; introducing ammonia gas into the fixed bed reactor for 5 minutes, introducing the first mixed material into the fixed bed reactor, and controlling the reaction temperature to be 120°C, the reaction pressure to be 11 MPa, and the reaction time to be 3 hours to obtain an isopropanolamine mixed material. After testing, the isopropanolamine mixture contained 90.3% monoisopropanolamine by mass.

[0073] By comparing Example 8 with Example 12, it can be seen that the use of 4A molecular sieve and 3A molecular sieve and ZSM-5 molecular sieve in a mass ratio of 8:2 as catalysts all have better monoisopropanolamine selectivity.

[0074] Embodiment 13

[0075] A method for preparing isopropanolamine comprises: spraying deionized water onto a 3A molecular sieve until the water absorption of the 3A molecular sieve is 100 mg / g, spraying deionized water onto a ZSM-5 molecular sieve until the water absorption of the ZSM-5 molecular sieve is saturated, mixing the 3A molecular sieve and the ZSM-5 molecular sieve in a mass ratio of 8:2, loading the mixed catalyst into a fixed bed reactor, preheating propylene oxide to 80°C and heating liquid ammonia to 75°C respectively using a plate heat exchanger, then introducing propylene oxide and liquid ammonia in a molar ratio of 12:1 into a mixer, mixing and heating to 95°C to obtain a first mixed material; introducing ammonia gas into the fixed bed reactor for 5 minutes, introducing the first mixed material into the fixed bed reactor, and controlling the reaction temperature to be 120°C, the reaction pressure to be 11 MPa, and the reaction time to be 3 hours to obtain an isopropanolamine mixed material. After testing, the isopropanolamine mixture contained 92.2% monoisopropanolamine by mass.

[0076] By comparing Example 12 with Example 13, it can be seen that the mixed catalyst composed of 3A molecular sieve and ZSM-5 molecular sieve in a mass ratio of 8:2 has better monoisopropanolamine selectivity under the condition that the molar ratio of propylene oxide to liquid ammonia is 12:1.

[0077] Embodiment 14

[0078] A method for preparing isopropanolamine comprises: spraying deionized water onto a 3A molecular sieve until the water absorption of the 3A molecular sieve is 105 mg / g, spraying deionized water onto a ZSM-5 molecular sieve until the water absorption of the ZSM-5 molecular sieve is saturated, mixing the 3A molecular sieve and the ZSM-5 molecular sieve in a mass ratio of 8:2, loading the mixed catalyst into a fixed bed reactor, preheating propylene oxide to 80°C and heating liquid ammonia to 75°C respectively using a plate heat exchanger, then introducing propylene oxide and liquid ammonia in a molar ratio of 12:1 into a mixer, mixing and heating to 95°C to obtain a first mixed material; introducing ammonia gas into the fixed bed reactor for 5 minutes, introducing the first mixed material into the fixed bed reactor, and controlling the reaction temperature to be 120°C, the reaction pressure to be 11 MPa, and the reaction time to be 3 hours to obtain an isopropanolamine mixed material. After testing, the isopropanolamine mixture contained 91.8% monoisopropanolamine by mass.

[0079] Embodiment 15

[0080] A method for preparing isopropanolamine comprises: spraying deionized water onto a 3A molecular sieve until the water absorption of the 3A molecular sieve is 95 mg / g, spraying deionized water onto a ZSM-5 molecular sieve until the water absorption of the ZSM-5 molecular sieve is saturated, mixing the 3A molecular sieve and the ZSM-5 molecular sieve in a mass ratio of 8:2, loading the mixed catalyst into a fixed bed reactor, preheating propylene oxide to 80°C and heating liquid ammonia to 75°C respectively using a plate heat exchanger, then introducing propylene oxide and liquid ammonia in a molar ratio of 12:1 into a mixer, mixing and heating to 95°C to obtain a first mixed material; introducing ammonia gas into the fixed bed reactor for 5 minutes, introducing the first mixed material into the fixed bed reactor, and controlling the reaction temperature to be 120°C, the reaction pressure to be 11 MPa, and the reaction time to be 3 hours to obtain an isopropanolamine mixed material. After testing, the isopropanolamine mixture contained 91.0% monoisopropanolamine by mass.

[0081] By comparing Example 12 to Example 15, it can be seen that controlling the water absorption of the 3A molecular sieve in the mixed catalyst to 100 mg / g has better monoisopropanolamine selectivity.

[0082] Embodiment 16

[0083] A method for preparing isopropanolamine comprises: spraying deionized water onto a 3A molecular sieve until the water absorption of the 3A molecular sieve is 100 mg / g, spraying deionized water onto a copper-doped ZSM-5 molecular sieve until the water absorption of the copper-doped ZSM-5 molecular sieve is saturated, mixing the 3A molecular sieve and the copper-doped ZSM-5 molecular sieve in a mass ratio of 8:2, loading the mixed catalyst into a fixed bed reactor, preheating propylene oxide to 80°C and heating liquid ammonia to 75°C respectively using a plate heat exchanger, then introducing propylene oxide and liquid ammonia in a molar ratio of 12:1 into a mixer, mixing and heating to 95°C to obtain a first mixed material; introducing ammonia gas into the fixed bed reactor for 5 minutes, introducing the first mixed material into the fixed bed reactor, and controlling the reaction temperature to be 120°C, the reaction pressure to be 11 MPa, and the reaction time to be 3 hours to obtain an isopropanolamine mixed material. After testing, the isopropanolamine mixture contained 92.7% monoisopropanolamine by mass.

[0084] By comparing Example 13 with Example 16, it can be seen that when copper-doped ZSM-5 molecular sieve is used, the selectivity of monoisopropanolamine is better.

[0085] Embodiment 17

[0086] A method for preparing isopropanolamine comprises: spraying deionized water onto a 3A molecular sieve until the water absorption of the 3A molecular sieve is 105 mg / g, spraying deionized water onto a copper-doped ZSM-5 molecular sieve until the water absorption of the copper-doped ZSM-5 molecular sieve is saturated, mixing the 3A molecular sieve and the copper-doped ZSM-5 molecular sieve in a mass ratio of 8:2, loading the mixed catalyst into a fixed bed reactor, preheating propylene oxide to 80°C and heating liquid ammonia to 75°C using a plate heat exchanger, then introducing propylene oxide and liquid ammonia in a molar ratio of 12:1 into a mixer, mixing and heating to 95°C to obtain a first mixed material; introducing ammonia gas into the fixed bed reactor for 5 minutes, introducing the first mixed material into the fixed bed reactor, and controlling the reaction temperature to be 120°C, the reaction pressure to be 11 MPa, and the reaction time to be 3 hours to obtain an isopropanolamine mixed material. After testing, the isopropanolamine mixture contained 92.1% monoisopropanolamine by mass.

[0087] Embodiment 18

[0088] A method for preparing isopropanolamine comprises: spraying deionized water onto a 3A molecular sieve until the water absorption of the 3A molecular sieve is 95 mg / g, spraying deionized water onto a copper-doped ZSM-5 molecular sieve until the water absorption of the copper-doped ZSM-5 molecular sieve is saturated, mixing the 3A molecular sieve and the copper-doped ZSM-5 molecular sieve in a mass ratio of 8:2, loading the mixed catalyst into a fixed bed reactor, preheating propylene oxide to 80°C and heating liquid ammonia to 75°C respectively using a plate heat exchanger, then introducing propylene oxide and liquid ammonia in a molar ratio of 12:1 into a mixer, mixing and heating to 95°C to obtain a first mixed material; introducing ammonia gas into the fixed bed reactor for 5 minutes, introducing the first mixed material into the fixed bed reactor, and controlling the reaction temperature to be 120°C, the reaction pressure to be 11 MPa, and the reaction time to be 3 hours to obtain an isopropanolamine mixed material. After testing, the isopropanolamine mixture contained 91.9% monoisopropanolamine by mass.

[0089] By comparing Example 16 to Example 18, it can be seen that controlling the water absorption of the 3A molecular sieve in the mixed catalyst to 100 mg / g has better monoisopropanolamine selectivity.

[0090] Embodiment 19

[0091] A method for preparing isopropanolamine comprises: spraying deionized water on a 3A molecular sieve until the water absorption of the 3A molecular sieve is 100 mg / g, then loading the 3A molecular sieve into a fixed bed reactor, and then using a plate heat exchanger to preheat propylene oxide to 90°C and liquid ammonia to 90°C, respectively, and then passing propylene oxide and liquid ammonia with a molar ratio of 22:1 into a mixer, mixing and heating to 95°C to obtain a first mixture; passing ammonia gas into the fixed bed reactor for 5 minutes, passing the first mixture into the fixed bed reactor, and controlling the reaction temperature to 120°C, the reaction pressure to 11 MPa, and the reaction time to 3 hours to obtain an isopropanolamine mixture. After testing, the isopropanolamine mixture contains 89.3% monoisopropanolamine by mass.

[0092] By comparing Example 1 with Example 19, it can be seen that for 3A molecular sieve, increasing the preheating temperature has a certain effect on the selectivity of monoisopropanolamine.

[0093] Embodiment 20

[0094] A method for preparing isopropanolamine comprises: spraying deionized water on a 4A molecular sieve until the water absorption of the 4A molecular sieve is 105 mg / g, then loading the 4A molecular sieve into a fixed bed reactor, and then preheating propylene oxide to 90°C and heating liquid ammonia to 90°C respectively using a plate heat exchanger, then passing propylene oxide and liquid ammonia in a molar ratio of 18:1 into a mixer, mixing and heating to 95°C to obtain a first mixture; passing ammonia gas into the fixed bed reactor for 5 minutes, passing the first mixture into the fixed bed reactor, and controlling the reaction temperature to 120°C, the reaction pressure to 11 MPa, and the reaction time to 3 hours to obtain an isopropanolamine mixture. After testing, the isopropanolamine mixture contains 90.4% monoisopropanolamine by mass.

[0095] By comparing Example 8 with Example 20, it can be seen that for the 4A molecular sieve, the influence of the preheating temperature on the selectivity of monoisopropanolamine is relatively small.

[0096] Embodiment 21

[0097] A method for preparing isopropanolamine comprises: spraying deionized water onto a 3A molecular sieve until the water absorption of the 3A molecular sieve is 100 mg / g, spraying deionized water onto a ZSM-5 molecular sieve until the water absorption of the ZSM-5 molecular sieve is saturated, mixing the 3A molecular sieve and the ZSM-5 molecular sieve in a mass ratio of 8:2, loading the mixed catalyst into a fixed bed reactor, preheating propylene oxide to 90°C and heating liquid ammonia to 90°C respectively using a plate heat exchanger, then introducing propylene oxide and liquid ammonia in a molar ratio of 12:1 into a mixer, mixing and heating to 95°C to obtain a first mixed material; introducing ammonia gas into the fixed bed reactor for 5 minutes, introducing the first mixed material into the fixed bed reactor, and controlling the reaction temperature to be 120°C, the reaction pressure to be 11 MPa, and the reaction time to be 3 hours to obtain an isopropanolamine mixed material. After testing, the isopropanolamine mixture contained 92.0% monoisopropanolamine by mass.

[0098] Embodiment 22:

[0099] A method for preparing isopropanolamine comprises: spraying deionized water onto a 3A molecular sieve until the water absorption of the 3A molecular sieve is 100 mg / g, spraying deionized water onto a copper-doped ZSM-5 molecular sieve until the water absorption of the copper-doped ZSM-5 molecular sieve is saturated, mixing the 3A molecular sieve and the copper-doped ZSM-5 molecular sieve in a mass ratio of 8:2, loading the mixed catalyst into a fixed bed reactor, preheating propylene oxide to 90°C and heating liquid ammonia to 90°C respectively using a plate heat exchanger, then introducing propylene oxide and liquid ammonia in a molar ratio of 12:1 into a mixer, mixing and heating to 95°C to obtain a first mixed material; introducing ammonia gas into the fixed bed reactor for 5 minutes, introducing the first mixed material into the fixed bed reactor, and controlling the reaction temperature to be 120°C, the reaction pressure to be 11 MPa, and the reaction time to be 3 hours to obtain an isopropanolamine mixed material. After testing, the isopropanolamine mixture contained 92.6% monoisopropanolamine by mass.

[0100] By comparing Example 13, Example 16, Example 21, and Example 22, it can be seen that the preheating temperature has a certain influence on the selectivity of monoisopropanolamine of the mixed catalyst.

[0101] Although the present invention is disclosed as above, the present invention is not limited thereto. Any person skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the scope defined by the claims.

Claims

1. A method for preparing isopropanolamine, characterized in that: include: S100: mixing propylene oxide and liquid ammonia in a molar ratio of (5-30):1 to obtain a first mixed material; S200: catalyzing the first mixture with a zeolite catalyst to obtain an isopropanolamine mixture; Wherein, the weight ratio of aluminum to silicon in the zeolite catalyst is 0.8-2 or 50-150.

2. The method for preparing isopropanolamine according to claim 1, wherein The zeolite catalyst is at least one of type A molecular sieve and ZSM-5 molecular sieve.

3. The method for preparing isopropanolamine as claimed in claim 2, characterized in that, The type A molecular sieve is at least one of a type 3A molecular sieve and a type 4A molecular sieve, and the water absorption capacity of the type A molecular sieve is 80 mg / g-130 mg / g.

4. The method for preparing isopropanolamine as claimed in claim 3, characterized in that, When 3A type molecular sieve is selected, the S100 is a mixture of propylene oxide and liquid ammonia in a molar ratio of (20-30):

1.

5. The method for preparing isopropanolamine as claimed in claim 3, characterized in that, When 4A type molecular sieve is selected, the S100 is a mixture of propylene oxide and liquid ammonia in a molar ratio of (15-25):

1.

6. The method for preparing isopropanolamine as claimed in claim 2, characterized in that, When ZSM-5 molecular sieve is selected, the S100 is a mixture of propylene oxide and liquid ammonia in a molar ratio of (5-15):

1.

7. The method for preparing isopropanolamine according to claim 1, wherein The S100 specifically includes the following steps: Propylene oxide is preheated to 75° C.-95° C., and liquid ammonia is heated to 75° C.-95° C. respectively, and then introduced into a mixer for mixing and heated to 90° C.-100° C. to obtain the first mixed material.

8. The method for preparing isopropanolamine according to claim 1, wherein The S200 specifically includes the following steps: The first mixed material is introduced into a fixed bed reactor equipped with the zeolite catalyst, and the reaction temperature is controlled to be 100° C.-130° C., the reaction pressure is 10 MPa-15 MPa, and the reaction time is 2 h-5 h to obtain the isopropanolamine mixed material.

9. The method for preparing isopropanolamine according to claim 8, wherein The isopropanolamine mixture contains 88%-95% of monoisopropanolamine.

10. The method for preparing isopropanolamine according to claim 8, characterized in that: Before the first mixed material is introduced into the fixed bed reactor, ammonia gas is introduced into the fixed bed reactor for 3 min to 7 min.