Reaktion #50779

Reaktionsgleichung

hydrochloric acid

4-hydroxymandelic acid

sodium

ethylene oxide

→

4-(2-hydroxyethoxy)mandelic acid

Ausbeute 89.3%

Lösungsmittel

water

Reaktionsbedingungen

Aufarbeitung

1. 1
   workup.STIRRINGstirred at this temperature for another 2 hours
2. 2
   workup.ADDITIONThe still hot reaction mixture is poured into another vessel
3. 3
   Sonstigecrystallized
4. 4
   Temperaturby slow cooling to about +10° C
5. 5
   FiltrationThe precipitated product is filtered with 1000 ml of cold water
6. 6
   Sonstigedried

Vorschrift

1040.8 g (5.00 mol) of 4-hydroxymandelic acid, sodium salt monohydrate, 10.0 g (0.25 mol) of sodium hydroxide and 1000 ml of water are placed in an autoclave of 6.3 liter capacity. The autoclave is flushed with nitrogen and 330.4 g (7.50 mol) of ethylene oxide are then injected. The contents are slowly heated to 95° C. over a period of 2 hours with stirring and stirred at this temperature for another 2 hours. The still hot reaction mixture is poured into another vessel, acidified at 95° C. with 540 ml (about 5.5 mol) of 32% hydrochloric acid and crystallized by slow cooling to about +10° C. The precipitated product is filtered with 1000 ml of cold water and dried to give 948 g (89%) of 4-(2-hydroxyethoxy)mandelic acid, m.p. 162°-164° C. (compound (201), Table 2).

Quelle