Distillative freezing process for purifying monomers etc. - by vaporising crude mixt. at below triple point temp. and pressure

摘要

Process for sepg. a mixt., at least partly liq., contg. >=2 volatile components A and B comprises concurrently vaporising A and B at a temp. and pressure below the triple temp. and pressure (TT and PT) of pure B so as to prod. (a) vapour (v) and (b) condensed mass (M) consisting of mother liquor and B-enriched solid. The A-B mixt. has a constant -pressure phase diagram (at a 3-phase pressure) with a 2-phase (B-enriched solid and vapour) region over a wide concn. range above the 3-phase temp., and a 2-phase, (B-enriched solid and liq.) region, below this temp. Pref. (V) is cooled at pressure P PT to form a condensed mass (M2) comprising B-enriched solid phase. This is (partly) melted by heating at > P. Used for purifying a wide range of cpds., e.g. monomers, particularly where A and B have closely similar b. pts.