1-Chloro-acetone stabilisation with tert. amine - esp. di:iso-propyl-ethyl-amine, giving long-term stability without impairing reactivity

摘要

Stabilisation of 1-chloroacetone (I) is effected by adding a tert. amine of formula NR1R2R3 (II) as stabiliser (where R1=alkyl with at least 2C, cycloalkyl, cycloalkylalkyl or aralkyl; R2-3 independently=alkyl with at least 3C, cycloalkyl, cycloalkylalkyl or aralkyl). (II) is pref. di-isopropyl-ethylamine (IIA); and added to (I) in an amt. of 0.2-2 (wt.)%. ADVANTAGE - Stabilisation is simple, effective and long-lasting, even when (I) is exposed to light or elevated temp. (II) does not interfere in the usual reactions of (I). In an example, freshly distilled (I) was mixed with 0.2% (IIA) and kept in a brown glass bottle at room temp. After 6 months, there was no discolouration and no decomposition prods. could be detected by gas chromatography. Samples of freshly distilled (I) contg. (A) no stabiliser, (B) 0.5% CaCO3, (C) 0.05% (IIA), (D) 0.1% (IIA), (E) 0.2% (IIA), (F) 0.5% (IIA), (G) 0.75% (IIA) were kept at room temp./60 deg.C. The pH of the aq. extract was (A) 6.2/5.8 star, (B) 6.5/6.0, (C) 6.6/6.2, (D) 6.3/6.3, (E) 6.4/6.4, (F) 6.5/6.3, (G) 6.3/6.5 after 3 days; (A) 6.3/1.1star, (B) 6.6/4.8star, (C) 6.5/6.3, (D) 6.6/6.2, (E) 6.5/6.2, (F) 6.7/7.2, (G) 6.5/6.4 after 5 days; and (A) 5.6star/0.5star, (B) 6.2star/0.9star, (C) 6.6/1.7star, (D) 6.5/3.6star, (E) 6.3/6.3, (F) 6.2/6.2, (G) 6.6/6.5 after 14 days. Star indicates that the sample had become yellow.