A simultaneous cooling and dielectric heating: an advanced technology to improve the yield of lactides

• Main Authors: Idris, Ani, Bukhari, Attaullah, Mohd. Yusof, Noordin, Tan, K. G.
• Format: Conference or Workshop Item
• Published: 2012
• Subjects: QD Chemistry
• Online Access: http://eprints.utm.my/id/eprint/34415/; https://pure.utm.my/en/publications/a-simultaneous-cooling-and-dielectric-heating-an-advanced-technol

Lactides with improved yield are prepared by depolymerization of oligo (lactic acid) under simultaneous cooling and microwave heating. The influence of microwave power input and its non-thermal effects on the yield of lactides are investigated. By increasing microwave power input, increased yield of lactides is obtained at 180–220◦C at reduced pressure. Combined application of simultaneous cooling with microwave heating further increased the lactides yield. The removal of lactides during reaction shifts the equilibrium to the right. Simultaneous cooling enhances the absorbance of microwave irradiation into reactants; though increased yield of lactides is not only due to thermal effects of microwave irradiation. Maximum 85% yield of lactides is obtained at 500W microwave power at 180–220◦C and < 20 torr.