Verfahren zur Herstellung von N-Acetyl-D,L-alpha-aminocarbonsäuren

摘要

Known acetylation processes for producing N-acetyl-D,L- alpha -aminocarboxylic acids from the corresponding D,L- alpha -aminocarboxylic acids by acetylation with acetic anhydride in acetic acid and isolation of the resulting N-acetyl-D,L- alpha -aminocarboxylic acids from the acetylation mixture either result in the production of large quantities of salts or require an aqueous treatment to isolate the N-acetylated alpha -amino acids in sufficiently pure form. By carrying out the acetylation at 60-150 DEG C in a concentration of < 3 mol alpha -aminocarboxylic acid per litre acetic acid (concentration under standard conditions of pressure and temperature) and obtaining the N-acetyl-D,L- alpha -aminocarboxylic acid by concentration in liquefied or solid form, the aqueous treatment can be dispensed with entirely, although high quality is still obtained in terms of both yield and purity. Also disclosed are N-acetyl-D,L- alpha -aminocarboxylic acids for use in the enzymatic splitting operation in a process for producing optically active alpha -aminocarboxylic acids.