Process for the continuous preparation of benzyl alcohol

• Main Authors: HOFFMANN ERHARD-GUNTHER DR, BUYSCH HANS-JOSEF DR, OOMS PIETER DR, SCHENKE BERND-ULRICH, JANSEN URSULA DR
• Format: Patent
• Language: Czech; English
• Published: 11.12.2002
• Edition: 7
• Subjects: ACYCLIC OR CARBOCYCLIC COMPOUNDS; CHEMISTRY; METALLURGY; ORGANIC CHEMISTRY

Zp sob v²roby benzylalkoholu hydrol²zou benzylchloridu p°i zv² en²ch teplot ch. Voda a benzylchlorid se d vkuj kontinu ln do reaktoru s disperga n m za° zen m, reak n produkt se po ·pln p°em n rozd l na organickou a vodnou f zi, organick f ze se kontinu ln zav d do prvn destila n kolony a rozd luje se za tlaku 0,1 a 95 kPa na benzylchlorid, kter² se odeb r z hlavy kolony a zav d se zp t do reaktoru a na surov² benzylalkohol, kter² se zav d do druh destila n jednotky a z t vych z jako ist² benzylalkohol vedle produktu z paty kolony, obsahuj c ho doprovodn produkty. Vodn , kyselinu chlorovod kovou obsahuj c f ze, se zpracuje v extrak n aparatu°e s rozpou t dlem, p°i em se vyjmou ve vod rozpu t n organick l tky, extrakt se ve t°et destila n jednotce zbav rozpou t dla a produkt z paty t°et destila n jednotky se zav d do prvn destila n aparatury a kyselinu chlorovod kovou obsahuj c vodn f ze se po extrakci vede k zakoncentrov n chlorovod ku.\ The present invention relates to a process for the preparation of benzyl alcohol by hydrolysis of benzyl chloride with water at elevated temperature, wherein the preparation process is characterized in that a) benzyl chloride and water are continuously fed into a reactor containing dispersion devices, b) the reaction product, after exiting the reactor, is separated in a separator into an aqueous and organic phase, c) the organic phase is separated at a pressure ranging from about 0.1 to 95 kPa in a first distillation apparatus into benzyl chloride and crude benzyl alcohol, d) this benzyl chloride being withdrawn from the column head is recycled to the reactor, e) the crude benzyl alcohol is refined in a second distillation unit to give high-purity benzyl alcohol and a bottom phase containing the by-products being produced, f) the aqueous phase from the separator of the step b), containing hydrochloric acids is treated in an extraction apparatus with a solvent to extract organic constituents being dissolved in water, g) in a third distillation apparatus, this extract is freed of solvent which returns to the extractor, h) the bottom phase from the third distillation unit is passed to the first distillation apparatus in order to recover, and i) the aqueous hydrochloric acid from the extraction, after taking off residual organics, is passed into an HCl absorption unit in order to recover and concentrate HCl to make high-purity HCl.