A device for installing a bolt retainer onto a bolt includes a support bar and a handle attached to the support bar. Both, the D and L-enantiomers are obtained according to the invention in a industrially feasable process by adding chiral enantioselective polymers to the supersaturated solution of the racemat to inhibit crystalization of one enantiomer. Multiple feedback loops are adopted in the present invention, which can low the distortion of the switching amplifier to the extent.