| 摘要 |
<p>1515620 Preparation of alkyl acrylates HOECHST AG 18 Nov 1976 [26 Nov 1975] 48108/76 Heading C2C In a continuous process for the preparation of alkyl acrylates free from ether by reacting acrylic acid with an alkanol (C 1 -C 4 ) in a molar ratio of 1 : 1 to 1 : 2 in liquid phase at temperatures 80‹ to 130‹ C. under 100 to 760 mm. Hg pressure in the presence of an acid catalyst, followed by distillative purification the reaction mixture containing sulphuric acid 0À1 to 3 wt.% or organic sulphonic acid 1-8 wt.% is introduced to a reaction zone (2) and the mixture reacted for 4-10 hours, an azeotropic mixture of alkyl acylate, reaction water and unreacted alkanol is distilled off near the top of a first distilling zone (4), condensed and separated into aqueous and organic phase (6), a portion of the organic phase recycled and if C 3 -C 4 alkanol a portion of the aqueous phase is recycled (7), the remaining aqueous phase removed and the balance of the organic phase passed (12) to second distilling zone (13), distilling overhead an azeotropic mixture of alkanol and ester, condensing and recycling and removing the ether-free acrylate through the base of the distilling zone, and in addition continuously taking a portion of the reaction mixture from the reaction zone, distilling off high-boiling matter, replacing catalyst loss and recycling distillate to the reaction zone.</p> |
