Preparation method of 2-amino-2-methyl-1-propanol

Abstract

The invention discloses a preparation method of 2-amino-2-methyl-1-propanol. The preparation method comprises the following step: carrying out a ring-opening reaction on methyl propylene oxide and liquid ammonia in the presence of an acidic catalyst to prepare the 2-amino-2-methyl-1-propanol. The preparation method provided by the invention is beneficial to control of the reaction in the primary substitution stage of ammonia, namely generation of 2-amino-2-methyl-1-propanol, almost no disubstituted product di (1-hydroxy-2, 2 '-dimethyl) amine of ammonia is produced, the product selectivity is high, the raw materials are easy to obtain, and the cost is low.

Description

Technical Field

[0001] The invention belongs to the field of 2-amino-2-methyl-1-propanol production, and more specifically relates to a method for preparing 2-amino-2-methyl-1-propanol from methyl propylene oxide. Background Art

[0002] 2-Amino-2-methyl-1-propanol is a white crystal or colorless viscous liquid, which is usually used as a 95% by mass aqueous solution. It is an important organic synthesis raw material and is widely used in coatings, inks, metalworking fluids, personal care and pharmaceutical intermediates. Its molecular formula is as follows:

[0003]

[0004] The classic synthetic route of 2-amino-2-methyl-1-propanol is to use 2-nitropropane as the starting material, react it with formaldehyde for hydroxymethylation to obtain 2-nitro-2-methyl-1-propanol, and then catalytic reduction to obtain 2-amino-2-methyl-1-propanol. This route uses propane nitration to prepare the raw material 2-nitropropane, and the nitration selectivity is low and it is very easy to explode.

[0005] Patent CN1911899A uses isobutylene as the main raw material, chlorine and acetonitrile as auxiliary materials, and uses Ritter reaction to carry out a series of reactions such as chlorination, cyclization, ring opening, hydrolysis, acid-base neutralization, and then obtains 2-amino-2-methyl-1-propanol product through distillation. The reaction preparation steps are many and the overall yield is low (50-69%).

[0006] Patent CN105418440A uses isopropylamine and synthesis gas as raw materials, and carries out hydroformylation reaction in the presence of specific catalysts and ligands to synthesize the target product, with a yield of up to 93%. However, the reaction conditions are harsh, the temperature and pressure are high, and specific catalyst ligands and solvents are required.

[0007] Patent CN1810767A uses isopropanol to react with sodium nitrite and paraformaldehyde at 0-25°C, and then extracts, washes and distills to obtain 2-nitro-2-methyl-1-propanol, which is then catalytically hydrogenated to obtain the product. The patent does not give specific reaction conditions and yields. The disadvantages of this route are complex synthesis conditions, long reaction time, and difficulty in post-processing.

[0008] The existing methods for preparing 2-amino-2-methyl-1-propanol have problems such as demanding raw material sources, complex process flows, low yields, and high costs to varying degrees. It is urgent to find a new method for preparing 2-amino-2-methyl-1-propanol. Summary of the invention

[0009] In view of the above problems, the present invention proposes a method for preparing 2-amino-2-methyl-1-propanol. The acidic molecular sieve catalyst used in the present invention uses 2-amino-2-methyl-1-propanol as a structure directing agent or template agent, which is beneficial to control the reaction at the mono-substitution stage of ammonia, that is, to generate 2-amino-2-methyl-1-propanol, and almost no di-substitution product of ammonia, di(1-hydroxy-2,2'-dimethyl)amine, has high product selectivity, is easy to obtain raw materials, and has low cost.

[0010] To achieve the above object, the present invention adopts the following technical solution:

[0011] A method for preparing 2-amino-2-methyl-1-propanol comprises the following steps: subjecting methyl propylene oxide and liquid ammonia to a ring-opening reaction under an acidic catalyst condition to prepare 2-amino-2-methyl-1-propanol.

[0012] Its synthetic route is as follows:

[0013]

[0014] In the present invention, the liquid ammonia is anhydrous liquid ammonia, and the feed mass ratio of liquid ammonia to methyl propylene oxide is (2-5):1, preferably (2.5-3.5):1.

[0015] In the present invention, the reaction temperature is 90-200°C, preferably 120-140°C.

[0016] In the present invention, the reaction pressure needs to be set above the saturated vapor pressure of liquid ammonia, generally maintained at 6 to 14 MPa, preferably 9 to 12 MPa.

[0017] In the present invention, the reaction time is 30 to 90 minutes, preferably 50 to 70 minutes.

[0018] In the present invention, the acidic catalyst includes a solid acid catalyst, and further, the solid acid catalyst includes an acidic molecular sieve, a heteropoly acid, an acidic ion exchange resin, a metal oxide or a sulfide, etc. More preferably, the acidic catalyst is an acidic molecular sieve.

[0019] Preferably, the method for preparing the acidic molecular sieve mainly comprises the following steps:

[0020] S1: mixing an aluminum source, a silicon source, 2-amino-2-methyl-1-propanol, NaOH and water at 25-60° C. to obtain a gel mixture;

[0021] S2: placing the gel mixture obtained in step S1 into a hydrothermal synthesis reactor and crystallizing at 160-250° C. for 10-80 hours;

[0022] S3: After the crystallization is complete, the molecular sieve is obtained by filtering, washing and calcining;

[0023] In the present invention, the aluminum source described in step S1 includes one or more of activated alumina, aluminum isopropoxide, pseudo-boehmite, and aluminum sulfate; the silicon source includes one or more of amorphous silica gel, orthosilicate, and activated silicon dioxide.

[0024] In the present invention, the molar ratio of SiO2 in the silicon source, Al2O3 in the aluminum source, 2-amino-2-methyl-1-propanol, and NaOH:H2O in step S1 is 100:(0.2-1):(5-20):

[0025] (5~10):(200~300).

[0026] In the present invention, the calcination temperature in step S3 is 400-700° C., and the calcination time is 5-15 hours.

[0027] In the present invention, the amount of the acidic catalyst added is 2% to 20% of the mass of methyl propylene oxide, preferably 5 to 10%.

[0028] Preferably, after the reaction is completed, a mother liquor containing 2-amino-2-methyl-1-propanol is obtained, and the mother liquor is subjected to catalyst removal treatment, deamination treatment, and refining treatment to obtain 2-amino-2-methyl-1-propanol.

[0029] In the present invention, the solid catalyst obtained by the catalyst removal treatment can be recycled.

[0030] In the present invention, the deamination treatment adopts conventional separation means in the art, for example, multi-stage flash evaporation and / or distillation treatment.

[0031] In the present invention, the ammonia obtained by the deamination treatment can be reused after compression and condensation.

[0032] In the present invention, the refining treatment mainly includes light removal treatment, using conventional separation means in the art, for example, distillation, rectification or adsorption treatment.

[0033] The beneficial effects of the present invention are:

[0034] (1) Provided is a new route for preparing 2-amino-2-methyl-1-propanol, wherein methyl propylene oxide and anhydrous liquid ammonia are used as raw materials. The three-membered ring tension in the methyl propylene oxide is relatively large, and protonation occurs under the action of an acidic catalyst. The protonated methyl propylene oxide tends to generate tertiary carbon cations and primary carbon cations, and the tertiary carbon cations are more stable than the primary carbon cations. The three-membered ring of the methyl propylene oxide is then broken between the tertiary carbon oxygen bonds. At this time, the liquid ammonia acts as a nucleophilic reagent to attack the protonated methyl propylene oxide, thereby causing a nucleophilic substitution reaction similar to SN1, and obtaining the main product 2-amino-2-methyl-1-propanol;

[0035] (2) The present invention uses methyl propylene oxide and liquid ammonia as raw materials, and the product can be obtained in one step of synthesis. The raw materials are easy to obtain and the cost is low;

[0036] (3) The acidic molecular sieve catalyst provided by the present invention uses 2-amino-2-methyl-1-propanol as a structure-directing agent or template agent, which is beneficial to controlling the structure of the reaction pores in the molecular sieve, so that the reaction is controlled at the mono-substitution stage of ammonia, that is, 2-amino-2-methyl-1-propanol is generated, and almost no di-substitution product of ammonia, di(1-hydroxy-2,2'-dimethyl)amine, is produced;

[0037] (4) The reaction safety of the present invention is high, less three wastes are generated, and the equipment involved is conventional equipment, which is more suitable for industrial scale. DETAILED DESCRIPTION

[0038] The present invention is further described by specific examples, and the embodiments of the present invention are only used as an explanation of the present invention and do not limit the scope of the present invention.

[0039] Source of raw materials: Unless otherwise specified, all raw materials in the following preparation examples and embodiments were purchased from the market.

[0040] A) Preparation of acidic molecular sieve catalyst

[0041] Preparation Example 1

[0042] Pseudo-boehmite (0.7g, Al2O3 content 71.2%), NaOH (2.8g), and distilled water (45g) were prepared as component A, and silica sol (200g, SiO2 content 30wt%) and 2-amino-2-methyl-1-propanol (13.4g) were prepared as component B, and component A was then added dropwise to component B at 30°C. The mixture was stirred at room temperature to form a gel, aged for 1h, and then put into a stainless steel reactor, heated and allowed to stand for crystallization (170°C, 80h), until the crystallization was complete, filtered, washed, dried, and then calcined at 500°C in a muffle furnace for 10h to obtain molecular sieve I.

[0043] Preparation Example 2

[0044] According to certain ingredient requirements, alumina (1g), NaOH (4g), and distilled water (54g) are configured as component A, and tetraethyl orthosilicate (214.3g) and 2-amino-2-methyl-1-propanol (17.8g) are configured as component B, and component A is then added dropwise to component B at 45°C. Stirring to form a gel at room temperature, aging for 1h, and then putting it into a stainless steel reactor, heating it and standing it for crystallization (200°C, 15h), until the crystallization is complete, filtering, washing, and drying, and then calcining it at 600°C in a muffle furnace for 9h to obtain molecular sieve II.

[0045] Preparation Example 3

[0046] According to certain ingredient requirements, aluminum isopropoxide (0.8g), NaOH (2g), and distilled water (36g) are configured as component A, and silicon dioxide (60g) and 2-amino-2-methyl-1-propanol (4.5g) are configured as component B, and component A is then added dropwise to component B at 50°C. Stirring to form a gel at room temperature, aging for 1h, and then putting it into a stainless steel reactor, heating and standing for crystallization (250°C, 10h), until the crystallization is complete, filtering, washing, and drying, and then calcining at 400°C in a muffle furnace for 15h to obtain molecular sieve III.

[0047] Preparation Example 4

[0048] According to certain ingredient requirements, aluminum sulfate (1.6g), NaOH (3.2g), and distilled water (52.2g) are configured as component A, and silica sol (200g) and 2-amino-2-methyl-1-propanol (11.6g) are configured as component B, and component A is then added dropwise to component B at 60°C. Stir to form a gel at room temperature, age for 1h, and then put into a stainless steel reactor, heat up and stand for crystallization (170°C, 14h), until the crystallization is complete, filter, wash, dry, and then roast at 700°C in a muffle furnace for 5h to obtain molecular sieve IV.

[0049] Preparation Example 5

[0050] According to certain ingredient requirements, aluminum oxide (0.71g), NaOH (2.4g), and distilled water (36g) are configured as component A, silicon oxide (60g) and 2-amino-2-methyl-1-propanol (7.1g) are configured as component B, and component A is then added dropwise to component B at 25°C. Stirring to form a gel at room temperature, aging for 1h, and then putting it into a stainless steel reactor, heating and standing for crystallization (190°C, 13h), until the crystallization is complete, filtering, washing, drying, and then calcining at 500°C in a muffle furnace for 15h to obtain molecular sieve V.

[0051] B) Embodiment

[0052] Analysis method: Agilent 7890A (FID) detector, INNOWAX column, injection port 300°C, detector 300°C; heating program: 100°C, constant temperature for 1 min, then increase to 200°C at a rate of 20°C / min, and hold for 8 min.

[0053] Example 1

[0054] 6.5g of molecular sieve I was put into the reactor, and after nitrogen replacement for 3 times, 390g of liquid ammonia was pumped in, stirring was started, and the temperature was raised to 120°C by program, and the pressure was adjusted to 10MPa by high-pressure nitrogen, and 130g of methyl propylene oxide was pumped in and maintained for 60 minutes. After the reaction was completed, the product was filtered, flashed, deaminized under reduced pressure, and distilled to obtain the product. The product was analyzed by gas chromatography and mass balance, and the conversion rate of methyl propylene oxide was 98.8%, and the purity of the product 2-amino-2-methyl-1-propanol was 96.7%.

[0055] Example 2

[0056] 15g of molecular sieve II was put into the reactor, and after nitrogen replacement for 3 times, 300g of liquid ammonia was pumped in, stirring was started, and the temperature was raised to 100°C by program, and the pressure was adjusted to 9MPa by high-pressure nitrogen, and 150g of methyl propylene oxide was pumped in and maintained for 40 minutes. After the reaction was completed, filtration, pressure release flash evaporation, reduced pressure deamination, vacuum demethyl propylene oxide, gas chromatography analysis of the product, and mass balance, it was obtained that the conversion rate of methyl propylene oxide was 99.5%, and the purity of the product 2-amino-2-methyl-1-propanol was 95.1%.

[0057] Example 3

[0058] 6g of molecular sieve III was put into the reactor, and after nitrogen replacement for 3 times, 200g of liquid ammonia was pumped in, stirring was started, and the temperature was raised to 150°C by program, and the pressure was adjusted to 13MPa by high-pressure nitrogen, and 40g of methyl propylene oxide was pumped in and maintained for 30 minutes. After the reaction was completed, filtration, pressure release flash evaporation, reduced pressure deamination, vacuum demethyl propylene oxide, gas chromatography analysis of the product, and mass balance, it was obtained that the conversion rate of methyl propylene oxide was 99.4%, and the purity of the product 2-amino-2-methyl-1-propanol was 97.2%.

[0059] Example 4

[0060] 6g of molecular sieve IV was put into the reactor, and after nitrogen replacement for 3 times, 135g of liquid ammonia was pumped in, stirring was started, and the temperature was raised to 200°C by program, and the pressure was adjusted to 14MPa by high-pressure nitrogen, and 30g of methyl propylene oxide was pumped in and maintained for 30min. After the reaction was completed, filtration, pressure release flash evaporation, reduced pressure deamination, vacuum demethyl propylene oxide, gas chromatography analysis of the product, and mass balance, it was obtained that the conversion rate of methyl propylene oxide was 99.4%, and the purity of the product 2-amino-2-methyl-1-propanol was 96.9%.

[0061] Example 5

[0062] 3.12g of molecular sieve V was put into the reactor, and after nitrogen replacement for 3 times, 390g of liquid ammonia was pumped in, stirring was started, and the temperature was raised to 90°C by program, and the pressure was adjusted to 6MPa by high-pressure nitrogen, and 156g of methyl propylene oxide was pumped in and maintained for 70min. After the reaction was completed, filtration, pressure release flash evaporation, reduced pressure deamination, vacuum demethyl propylene oxide, gas chromatography analysis of the product, and mass balance, it was obtained that the conversion rate of methyl propylene oxide was 97.5%, and the purity of the product 2-amino-2-methyl-1-propanol was 95.8%.

[0063] Example 6

[0064] 6.5g HZSM-5 was put into the reactor, and after nitrogen replacement for 3 times, 390g liquid ammonia was pumped in, stirring was started, and the temperature was raised to 120°C by program, and the pressure was adjusted to 10MPa by high-pressure nitrogen, and 130g methyl propylene oxide was pumped in and maintained for 60min. After the reaction was completed, the pressure was released for flash evaporation, deamination under reduced pressure, and methyl propylene oxide was removed by vacuum. The product was analyzed by gas chromatography and mass balance, and the conversion rate of methyl propylene oxide was 92.2%, and the purity of the product 2-amino-2-methyl-1-propanol was 75.3%.

[0065] Example 7

[0066] 6.5g of perfluorosulfonic acid resin was put into the reactor, and after nitrogen replacement for 3 times, 390g of liquid ammonia was pumped in, stirring was started, and the temperature was raised to 120°C by program, and the pressure was adjusted to 10MPa by high-pressure nitrogen, and 130g of methyl propylene oxide was pumped in and maintained for 60min. After the reaction was completed, the pressure was released for flash evaporation, deamination under reduced pressure, and methyl propylene oxide was removed by vacuum. The product was analyzed by gas chromatography and mass balance, and the conversion rate of methyl propylene oxide was 93.5%, and the purity of the product 2-amino-2-methyl-1-propanol was 74.9%.

[0067] Comparative Example 1

[0068] 6.5g of inert porcelain balls were put into the reactor, and after nitrogen replacement for 3 times, 390g of liquid ammonia was pumped in, stirring was started, and the temperature was raised to 120°C by program, and the pressure was adjusted to 10MPa by high-pressure nitrogen, and 130g of methyl propylene oxide was pumped in and maintained for 60min. After the reaction was completed, the pressure was released for flash evaporation, deamination under reduced pressure, and methyl propylene oxide was removed by vacuum. The product was analyzed by gas chromatography and mass balance, and the conversion rate of methyl propylene oxide was 75.1%, and the purity of the product 2-amino-2-methyl-1-propanol was 54.6%.

Claims

1. A method for preparing 2-amino-2-methyl-1-propanol, characterized in that: The following steps are involved: The methyl propylene oxide and liquid ammonia are subjected to a ring-opening reaction under acidic catalyst conditions to prepare 2-amino-2-methyl-1-propanol.

2. The preparation method according to claim 1, characterized in that: The liquid ammonia is anhydrous liquid ammonia, and the feed mass ratio of liquid ammonia to methyl propylene oxide is (2-5):1, preferably (2.5-3.5):

1.

3. The preparation method according to claim 1 or 2, characterized in that: The reaction temperature is 90-200°C, preferably 120-140°C; Preferably, the reaction pressure is 6 to 14 MPa, preferably 9 to 12 MPa; Preferably, the reaction time is 30 to 90 min, preferably 50 to 70 min.

4. The preparation method according to any one of claims 1 to 3, characterized in that: The acidic catalyst comprises a solid acid catalyst; Preferably, the solid acid catalyst comprises an acidic molecular sieve, a heteropolyacid, an acidic ion exchange resin, a metal oxide or a sulfide; Preferably, the acidic catalyst is an acidic molecular sieve.

5. The preparation method according to claim 4, characterized in that: The preparation method of the acidic molecular sieve mainly comprises the following steps: S1: mixing an aluminum source, a silicon source, 2-amino-2-methyl-1-propanol, NaOH and water at 25-60° C. to obtain a gel mixture; S2: placing the gel mixture obtained in step S1 into a hydrothermal synthesis reactor and crystallizing at 160-250° C. for 10-80 hours; S3: After the crystallization is complete, filter, wash and calcine to obtain the molecular sieve.

6. The preparation method according to claim 5, characterized in that: The aluminum source described in step S1 includes one or more of activated alumina, aluminum isopropoxide, pseudo-boehmite, and aluminum sulfate; the silicon source includes one or more of amorphous silica gel, orthosilicate, and activated silicon dioxide; Preferably, in step S1, the molar ratio of SiO2 in the silicon source, Al2O3 in the aluminum source, 2-amino-2-methyl-1-propanol, and NaOH:H2O is 100:(0.2-1):(5-20):(5-10):(200-300).

7. The preparation method according to claim 5, characterized in that: In step S3, the calcination temperature is 400-700° C. and the calcination time is 5-15 hours.

8. The preparation method according to any one of claims 1 to 7, characterized in that: The amount of the acidic catalyst added is 2% to 20% of the mass of methyl propylene oxide, preferably 5% to 10%.

9. The preparation method according to any one of claims 1 to 8, characterized in that: After the reaction is completed, a mother liquor containing 2-amino-2-methyl-1-propanol is obtained, and the mother liquor is subjected to catalyst removal treatment, deamination treatment, and refining treatment to obtain 2-amino-2-methyl-1-propanol.

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