Lactide was synthesized by polycondenzation of lactic acid at 180 °C and a 5.3 kPa for 120 minutes, and a subsequent depolymerization at 220 °C and 5.3 kPa for 40 minutes using dehydrated tin chloride as catalyst. A new reaction separation system was used, collecting the lactide in solid form and leaving water and lactic acid as vapor. This guarantees a high purity product and avoids any reversible reaction of lactide.