Org. Synth. 1946, 26, 38
DOI: 10.15227/orgsyn.026.0038
2-ISOPROPYLAMINOETHANOL
[Ethanol, 2-isopropylamino-]
Submitted by Evelyn M. Hancock and Arthur C. Cope.
Checked by Nathan L. Drake and Larry Green.
1. Procedure
The reaction is carried out in a catalytic hydrogenation apparatus similar to the one described by Adams and Voorhees.
1 In a
1-l. reduction bottle are placed
0.5 g. of platinum oxide catalyst
1 and
50 ml. of commercial absolute ethanol. The bottle is connected to a
calibrated low-pressure hydrogen tank and alternately evacuated and filled with
hydrogen twice.
Hydrogen is then admitted to the system until the pressure is 1–2 atm. (15–30 lb.), and the bottle is shaken for 20–30 minutes to reduce the
platinum oxide (Note 1). The shaker is stopped, air is admitted to the bottle, and a solution of
61.0 g. (1.0 mole) of ethanolamine (Note 2),
75.4 g. (94 ml., 1.3 moles) of acetone, and
100 ml. of absolute ethanol is rinsed into the reduction bottle with
50 ml. of absolute ethanol. The bottle is alternately evacuated and filled with
hydrogen twice.
Hydrogen is admitted to the system until the pressure is approximately 25 lb., and the bottle is shaken until the pressure drop indicates that the theoretical amount
(1 mole) of hydrogen has been taken up and absorption ceases (6–10 hours). Air is admitted to the bottle, and the catalyst is removed by filtration through a
Hirsch funnel with a filter plate of small diameter (Note 3). The bottle is rinsed with a total of
75ml. of benzene, which is also poured through the funnel. The filtrate is rinsed into a
500-ml. modified Claisen flask with
25 ml. of benzene, and most of the solvent is distilled at atmospheric pressure. Distillation of the residue under reduced pressure yields
97–98 g. of
2-isopropylaminoethanol, b.p.
86–87°/23 mm. (
94–95%, based on the
ethanolamine used)
(Note 4).
2. Notes
1.
If hydrogenation of the reaction mixture is begun in the presence of
platinum oxide, a long induction period or lag occurs before the catalyst is reduced.
2.
Commercial ethanolamine (Carbide and Carbon Chemicals Corporation) was dried by distillation with a small amount of
benzene and redistilled; b.p.
70–72°/12 mm.3.
The usual precaution was observed of keeping the catalyst wet with the solution being filtered to prevent ignition of the
filter paper.
4.
Similar procedures have been used in preparing other 2-alkylaminoethanols
2 and N-alkyl derivatives of
1-amino-2-propanol,
2-amino-1-propanol,
3-amino-1-propanol,
2-amino-1-butanol, and
1-amino-2-methyl-2-propanol.
3
3. Discussion
2-Isopropylaminoethanol has been prepared by the reaction of
isopropylamine with
ethylene oxide,
4,5 and by the method given above.
2
This preparation is referenced from:
Appendix
Chemical Abstracts Nomenclature (Collective Index Number);
(Registry Number)
ethanol (64-17-5)
Benzene (71-43-2)
hydrogen (1333-74-0)
platinum oxide
acetone (67-64-1)
Ethylene oxide (75-21-8)
ethanolamine (141-43-5)
2-isopropylaminoethanol,
Ethanol, 2-isopropylamino- (109-56-8)
1-amino-2-methyl-2-propanol (2854-16-2)
isopropylamine (75-31-0)
3-amino-1-propanol (156-87-6)
2-amino-1-butanol (13054-87-0)
1-amino-2-propanol (78-96-6)
2-amino-1-propanol (6168-72-5)
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