Réaction #1773090

Équation de réaction

D-phenylglycine

water

hydrochloric acid

→

D-cyclohexylglycine

Solvants

isopropanol

Conditions de réaction

Traitement

1. 1
   workup.ADDITIONthe reaction mixture is introduced into a 2 l hydrogenation autoclave
2. 2
   Lavageis rinsed with hydrogen twice
3. 3
   ExtractionThe still hot reaction solution is extracted with
4. 4
   Filtrationa nutsch filter
5. 5
   Lavagethe catalyst is washed with 200 ml
6. 6
   Autreis first adjusted at 40-60° C. to a pH of 2-2.5 with 50% sodium hydroxide solution, during which process
7. 7
   TempératureThe reaction mixture is cooled in an ice bath to a temperature of 0-10° C.
8. 8
   Extractionthe product is extracted with a nutsch filter
9. 9
   Lavagewashed with 300 ml
10. 10
    Autredried in a drying oven in vacuo at 50-70° C.

Mode opératoire

100 g (661.5 mmol) D-phenylglycine are dissolved or suspended in 890 ml deionised water, 290 ml isopropanol and 66.7 ml (802 mmol) 37% hydrochloric acid. After addition of 10 g of the Pt/Rh catalyst, 4% Pt+1% Rh on activated carbon (water content approx. 50%, corresponding to approx. 5 wt. % catalyst relative to D-phenylglycine used), the reaction mixture is introduced into a 2 l hydrogenation autoclave. After being rendered inert with nitrogen three times, it is rinsed with hydrogen twice, then a hydrogen overpressure of 8-10 bar is established and the reaction solution heated to 50-60° C. After approximately 6 to 8 hours, hydrogen uptake is completed (theoretical amount of H2 44.4 l). The hydrogenator is depressurised and once again rendered inert with nitrogen three times. The still hot reaction solution is extracted with a nutsch filter and the catalyst is washed with 200 ml deionised water. The filtrate is first adjusted at 40-60° C. to a pH of 2-2.5 with 50% sodium hydroxide solution, during which process the first crystals form. It is then stirred for a further 15-30 minutes at this pH and then adjusted to a pH of 5-6 with 50% sodium hydroxide solution. The reaction mixture is cooled in an ice bath to a temperature of 0-10° C., the product is extracted with a nutsch filter, washed with 300 ml deionised water and dried in a drying oven in vacuo at 50-70° C.

Source