The production process of 2-amino-2-methyl-1-propanol in foreign countries is synthesized from 2-nitropropane, such as Angus in the United States and AMP-95 of Dow Company, which can convert 2-nitropropane into 2-nitropropane. Propane is first reacted with formaldehyde for formylation, then the nitro group is reduced, and then 2-amino-2-methyl-1-propanol is obtained by separation. The synthetic route using 2-nitropropane as a raw material has its shortcomings, the raw material is dangerous, it is not easy to store and transport, the investment in production equipment is large, and it is difficult to prepare high-purity 2-amino-2-methyl-1-propanol.
Method 1. In order to solve the problems in the prior art that the raw materials for 2-amino-2-methyl-1-propanol are dangerous, the production investment is large, and the products are not easy to purify, CN200610053023.4 provides a kind of raw materials that are easy to obtain and cost effective. The preparation method of amino-2-methyl-1-propanol with low content and easy product purification.
A 500ml glass tube reactor was charged with 205.5g of acetonitrile (5mol), the two ports of the reaction flask were connected to bottom tubes, one was connected to the chlorine gas source, the other was connected to the isobutylene source, the other port was installed with a thermometer, and the reaction flask was placed Put into a 0°C ice-water bath, start magnetic stirring, and when the temperature of the system drops to 0°C, 63.8 g (0.9 mol) of chlorine and 50.5 g (0.9 mol) of isobutene are introduced into the reaction flask in the same proportion. Continue to stir for half an hour after aeration, then dropwise add 11 g of water (0.6 mol), stir for half an hour after dropwise addition, then filter, and vacuum the filtrate at about 45°C to obtain 83 g of a yellowish concentrated solution. Dissolve the concentrated solution obtained in the previous step with 41.5g of ethanol solution with a volume concentration of 95%, heat and stir until reflux, then add 29.05g of concentrated hydrochloric acid with a weight concentration of 37%, heat under reflux for about 2 hours, and then distill the system while heating. Add water, ethanol and ethyl acetate in the ethanol solution, add 41.5 g of ethanol solution and 12.45 g of concentrated hydrochloric acid, and continue to reflux for about 2 hours, distill out the solvent while heating, add water to the concentrate and vacuum distillation until there is no more distillate. , the obtained 66g viscous white solid is the hydrochloride of AMP.
The white AMP hydrochloride intermediate obtained in the previous step was neutralized with 55 g of sodium hydroxide solution with a mass concentration of 40% until pH=12, the water in the system was distilled off under reduced pressure, and then extracted with an ethanol solution with a volume concentration of 95%, and filtered. , the filtrate was evaporated to ethanol under reduced pressure to obtain 40 g of amp crude product, and the yield to isobutene was 50%. The obtained crude 2-amino-2-methyl-1-propanol is subjected to rectification to prepare a high-purity product, the content of which is greater than or equal to 99%.
Method two, CN201510712516.3 reported a kind of method of synthesizing 2-amino-2-methyl-1-propanol by isopropylamine, described isopropylamine and synthesis gas in the presence of metal catalyst, ligand and solvent , and the 2-amino-2-methyl-1-propanol is obtained by reacting at 100-200° C. and 0.8-20 MPa.
Get diphenyl ether 300g, isopropylamine 30g (0.51mol), palladium acetate 11.25g (50mmol) and triphenylphosphine 65.5g (250mmol), join successively in the 1000mL autoclave, the synthesis gas is passed into the autoclave When the pressure was 3MPa, the synthesis gas was a mixture of H2 and CO with a molar ratio of 1:1, and the stirring was started and the temperature was raised to 140 °C. When the temperature rose to 140°C, the pressure was supplemented with synthesis gas to 8MPa to start the timing reaction. During the reaction, the syngas pressure was supplemented intermittently to maintain the reaction pressure at 7-8 MPa. Gas chromatographic tracking found that isopropylamine was no longer converted in 6h, and the reaction was stopped by cooling at this time.
The reaction solution was taken out, distilled under reduced pressure at 2.5 kPa, and the fractions between 68 and 72°C were collected to obtain 40.85 g of pure 2-amino-2-methyl-1-propanol with a yield of 90%. At the same time, 422 g of distillation still residue was obtained.
The spectral data of pure 2-amino-2-methyl-1-propanol are as follows:
1H NMR (300 MHz, CDCl3, TMS as internal standard): 3.27 (s, 2H, -CH2-), 2.60 (brs, 3H, -OH, -NH2), 1.09 (s, 6H, CH3-).
FT-IR (KBr, σ/cm-1): 3340 (N-H st and O-H st), 2966 (C-H st), 1595 (N-Hδ), 1380 (C-Hδ), 1310 (C-N st), 1068 ( C-O st).
Fig. 1 is the hydrogen nuclear magnetic spectrum of pure 2-amino-2-methyl-1-propanol;
Figure 2 is the infrared spectrum of pure 2-amino-2-methyl-1-propanol.