| 摘要 |
<p>A reaction prod. stream from a reactor (in which a satd. monocarboxylic acid (I) is reacted with a formaldehyde cpd. (II)) comprising (I), an alpha, beta-ethylenically unsatd. aliphatic monocarboxylic acid (III), H2O, (II), and by-prods. is fractionally distilled so that a side stream is removed from the central part comprising 10-90% of the theoretical trays of the distn. column. (III) has one more C than (I). - Pref. (I) is propionic acid, to give methacrylic acid as (III). (II) is pref. formalin, MeOH/HCHO, paraformaldehyde, or trioxane, contg. pref. 70-99 wt.% HCHO.</p> |
