Description
L-lactide (3,6-dimethyl-1,4-dioxane-2,5-dione) is a cyclic lactone that is derived from lactic acid. It has the molecular formula C3H6O2 and is an essential building block for synthesizing polylactic acid (PLA) plastics, which are widely used in the manufacturing industry.
Chemical Properties
White crystal
Uses
(3
S)-
cis-3,6-Dimethyl-1,4-dioxane-2,5-dione may be used in the synthesis of optically active terpyridine containing poly(L-lactide)s, polydisperse lactic acid oligomers, bicyclic and tricyclic lactide derivatives.
Application
L-Lactide is a monomer used to produce polylactic acid (PLA), which is a biodegradable thermoplastic that has many uses in the pharmaceutical industry. Additionally, L-Lactide can be used to modify existing drug carriers or create new ones from scratch. As such, the pharmaceutical industry relies heavily on L-Lactide for its versatile applications.
Flammability and Explosibility
Non flammable
Synthesis
L-Lactide is a cyclic molecule obtained from L-lactic acid by a dehydration condensation reaction.
Purification Methods
This is the cyclic dilactone of lactic acid. The (±)-cis-racemate has been distilled with b 142o/8mm; the distillate which solidifies gives yellow needles on recrystallisation from EtOH with m 128o, from Et2O with m 129o, or CHCl3 with m 126o , 1720-1740 cm-1. It hydrolyses in cold max H2O. [Carothers et al. J Am Chem Soc 54 772 1932]. A trans-form (probably RS,SR) has been reported which crystallises from Et2O with m 42-43o [Hummel et al. Acta Cryst (Sect B) 38 1679 1982]. The R,R -(+)-lactide has b 150o/2mm and crystallises from Et2O with m 95o , or m 96.5 -97.5o (from CHCl3) or m 97.7o (from EtOAc) and [] D +297o (c 1.2, *C6H6). The S,S-(-)-lactide has b 150o/2.5mm and crystallises from EtOAc with m 98.7o, or m 95o (from CHCl3) or m 96.5-97.5o (from CCl4) and []D -297o (c 1.2, *C6H6). [Toniolo et al. J Org Chem 35 6 1970, Beilstein 19 H 154, 19 I 179, 19 II 176, 19 IV 1927, 19/5 V 10.]
