| 摘要 |
<p>An alkyl (meth)acrylate is prepared by a direct esterification (in 1) of (meth)acrylic acid by the corresponding alcohol, catalysed by H2SO4. The crude reaction mixture (B1), comprising the targeted ester, alcohol, (meth)acrylic acid, alkyl acid sulphate (alkyl hydrogen sulphate) and traces of H2SO4, is treated (in 3) with a base in order to neutralise the acid species, the resulting salts passing into the aqueous phase (A1), which is separated from the organic phase (O1) containing the targeted ester. The light products (L1), containing the alcohol, are recovered (in 4) from the aqueous phase and the waste water (E2) is discarded. The alkyl acid sulphate present in the aqueous phase (A1) resulting from the separation carried out after the neutralisation (in 3) is hydrolysed (in 8) to form, in this phase, alcohol and H2SO4, the acid species resulting from the hydrolysis are neutralised by introduction into the medium of a base and the resulting aqueous phase (A3) is sent to the alcohol recovery stage. Pollution of the waste water (E2), attributable to the alkyl acid sulphate, is thus avoided. <IMAGE></p> |
