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Method for the purification of an α-hydroxy acid on an industrial scale
The present invention relates to a method for the purification of an α-hydroxy acid on an industrial scale, in which the method involves: (a) subjecting an aqueous stream containing mainly α-hydroxy (1) to an extraction step, with the formation of an aqueous place containing mainly α-hydroxy acid (2), (b) concentrating the aqueous phase containing mainly α-hydroxy acid (2) by means of evaporation of water under reduced pressure, with the formation of a concentrated α-hydroxy acid solution in water (3), and (c) subjecting the concentrated α-hydroxy acid solution (3) to a crystallization, with formation of pure α-hydroxy acid (4), where (i) the concentrated α-hydroxy acid solution (3) is directly cooled in a melting crystallization device, and/or (ii) the concentrated α-hydroxy acid solution (3) is diluted with water and crystallization is brought about in one or more cooling crystallization devices and/or evaporative crystallization devices, and/or (iii) crystallization is brought about in one or more adiabatic crystallization devices.
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| Method+for+the+purification+of+an+α-hydroxy+acid+on+an+industrial+scale |
Apparatus and method for concentrating and collecting analytes from a flowing liquid stream
An apparatus for concentrating and collecting one or more analytes in a flowing liquid stream of a carrier solvent composed of one or more solvent components is provided, which includes a transfer tube which forms a bore having an inlet and an outlet, the inlet being adapted to accept the flowing liquid stream, and the outlet being adapted to form continuously replaced, hanging droplets of the liquid stream, and a collection device mounted below the outlet of the transfer tube for collecting the droplets. The apparatus includes a device for heating the liquid stream in the transfer tube to a temperature sufficient to cause partial evaporation of the carrier solvent from the hanging droplets but not exceeding the boiling point of the carrier solvent, and a device for heating the collection device to a temperature sufficient to cause further evaporation of the carrier solvent from the collected droplets. Also provided is a method for concentrating and collecting one or more analytes in a flowing liquid stream of a carrier solvent composed of one or more solvent components. The method includes the steps of introducing the liquid stream into a transfer tube which forms a bore having an inlet and an outlet, the inlet being adapted to accept the flowing liquid stream, and the outlet being adapted to form continuously replaced, hanging droplets of the liquid stream, and heating the liquid stream in the transfer tube while controlling the temperature of the liquid stream in the transfer tube to be sufficient to cause partial evaporation of the carrier solvent from the hanging droplets without exceeding the boiling point of the carrier solvent. The method allows the droplets to dislodge from the outlet, and the droplet is collected on a collection device mounted below the outlet of the transfer tube. The collection device is also heated to a temperature sufficient to cause further evaporation of the carrier solvent from the collected droplets.
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| Apparatus+and+method+for+concentrating+and+collecting+analytes+from+a+flowing+liquid+stream |
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