Patent ID: 8604237

Claim:
A method for the production of L-carnitine, comprising the steps of (a) providing a solution comprising at least 5% (w/w) carnitine in a first solvent, wherein the carnitine is a mixture of a mole fraction of D-carnitine and a mole fraction of L-carnitine, wherein the L-carnitine has an enantiomeric excess with respect to the D-carnitine, and wherein the enantiomeric excess is defined as the absolute difference between the mole fraction of L-carnitine and the mole fraction of D-carnitine in percent, (b) optionally seeding the solution with L-carnitine crystals, (c) adding a second solvent, in which the L-carnitine is not soluble or has a low solubility, and (d) isolating crystals comprising L-carnitine, wherein the first solvent is selected from the group consisting of ethanol, methanol, water, acetonitrile and mixtures thereof, and wherein the second solvent is selected from acetone, 2-butanone, methylacetate, ethylacetate, butylacetate, tetrahydrofuran, toluene and mixtures thereof, wherein in steps (a) to (d) the enantiomeric excess of the L-carnitine is enhanced by more than 2%.