Potassium Hydroxide → N1-(2,2-diethoxyethyl)hexane-1,6-diamine

참여 물질

반응 조건

반응 단계

Into a 1 L 3-neck RB flask was weighed hexamethylenediamine (59.0 g, 508 mmol). To this flask was then added 400 mL of 2-ethyl-1-butanol. Bromoacetaldehyde diethyl acetal (100.1 g, 507.7 mmol) and potassium hydroxide (29.0 g, 517 mmol) were weighed out and added to the reaction flask. A large egg-shaped magnetic stirrer follower was then placed in the flask and its side-arms stoppered with B19 glass stoppers and its centre-socket connected to a B24 double-layer coil condenser which was in turn connected to a nitrogen line and the apparatus flushed with a flow of nitrogen gas. The reaction mixture heated to 165° C. over a period of 30 minutes. As the reaction mixture neared reflux temperature (146° C.) the mixture started boiling quite vigorously indicative of an exotherm taking place and a white precipitate of potassium bromide (KBr) deposited from the solution and the colour of the reaction mixture changed from a pale yellow to an orange colour. The reaction mixture was refluxed for a further period of 5 hours under nitrogen before the reaction mixture allowed to cool slowly to room temperature under nitrogen. The reaction mixture was then filtered through a porosity 3 sinter to remove the KBr that had deposited from the reaction mixture. The 2-ethyl-1-butanol was then stripped from the filtrate by in vacuo distillation at a vacuum pressure of 14 torr and a heating oil bath temperature of 80-100° C. The residue in the distillation flask deposited additional pale yellow precipitate, presumably more KBr, necessitating the re-filtration of the concentrated reaction mixture. The collected solid was washed with 2×30 mL of diethyl ether. The filtrate and washings were combined and the ether component stripped off in vacuo using a rotary evaporator. The residue in the flask was then fractionally distilled in vacuo through a 30 cm glass column packed with 0.5 cm Fenske rings: Fraction 1: 23-36° C. (0.45 torr); a colourless liquid, presumably residual 2-ethyl-1-butanol. Fraction 2: 36-102° C. (0.35 torr); predominantly a white solid, unreacted hexamethylenediamine, that solidified in condenser. The apparatus was disassembled at this point so that a clean condenser could be substituted for that containing the hexamethylenediamine. Fraction 3: 106-109° C. (0.44 torr); colourless liquid which contained some white solid (residual hexamethylenediamine). On completion of the collection of the third fraction collection the apparatus was allowed to cool slowly to room temperature overnight under a nitrogen atmosphere. Next day the condenser containing most of the entrained white solid was substituted for a clean condenser and the distillation was re-started. Fraction 4: 112-115° C. (0.60 torr); colourless liquid containing a small amount of an entrained white solid.

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