(R)-(-)-3-Chloro-1,2-propanediol

Method 1 (CN202111237118.2):

After mixing and reacting (R)epichlorohydrin, (RR)Salen cobalt(III) catalyst completely, diluting with water, filtering, separating out the precipitate of (RR)Salen cobalt(III) catalyst, and then distilling the water under reduced pressure, and then distilling under reduced pressure to obtain (R)-3-chloro-1,2-propanediol. The (R)-3-chloro-1,2-propanediol prepared by this method has a chemical purity of >99.5% and a chiral purity (EE) of >99.8%, and has the advantages of simple synthesis, low cost, and easy to be applied industrially.

Method 2 (CN201510206172.9):

1) In the presence of an acidic catalyst, (S)-3-chloro-1,2-epoxypropane and water were subjected to a ring-opening reaction to obtain a ring-opening mixture; 

2) The base was subjected to a neutralization reaction with the ring-opening mixture to obtain the neutralized mixture; 

3) The alkali was neutralized with the ring-opening mixture to obtain the ring-opening mixture; 

4) The base was subjected to the ring-opening reaction with the ring-opening mixture;

5) The alkali was subjected to the ring-opening mixture. p>

3) Removing water from the neutralization mixture and filtering to obtain the filtrate; 

4) Fractionating the filtrate at 30-35 pa and 125-128C to produce (R)-3-chloro-1,2-propanediol.

This method has excellent yields, and the (R)-3-chloro-1,2-propanediol has excellent total purity and low water content, especially the chiral purity can be as high as 99.5%.