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Artikel_Effect of Temperature and Concentration of SnCl2 on Depolymerization Process of L-Lactide Synthesis from L-Lactic Acid via Short Polycondensation

Rahmayetty, Rahmayetty and Sukirno, Sukirno and Prasetya, Bambang and Gozan, Misri (2015) Artikel_Effect of Temperature and Concentration of SnCl2 on Depolymerization Process of L-Lactide Synthesis from L-Lactic Acid via Short Polycondensation. International Journal of Applied Engineering Research, 10 (21). pp. 41942-41946. ISSN 0973-4562

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Lactide is a group of cyclic ester, which is used to synthesize polylactic acid (PLA) by ring opening polymerization method. The properties of PLA depend strongly on the quality of the lactide monomer from which it is synthesized. In this research, lactide was synthesized from L-lactic acid through short polycondensation process without catalyst and depolymerization process with SnCl2 catalyst. The influences of temperature and catalyst concentration on the depolymerization were investigated to achieve high yield, high concentration and exact stereoform of the lactide produced. Polycondensation process of L-lactic acid was carried out gradually at 120 to 180oC for 5 h. Polycondensation produced oligomer with molecular weight (Mn) 2272-2390, (Mw) 2699-2911 and PDI 1.03 to 1.24. Yields of oligomer were between 79.63-83.64%. Depolymerization process was carried out at 76 torr for 3 h with variation of temperature of 190-220oC and concentration of SnCl2 0.05-0.2 % (w/w). The crude lactide yield increased with the raising of SnCl2 concentration and temperature up to 210oC. At temperature of 220oC, the reaction rate of oligomerization for heavy residue was much faster than the depolymerization for lactide produce, which resulted in a lower yield of lactide and more residu obtained. The highest yield of crude lactide was 78.8% with mass of SnCl2 catalyst used 0.1 (w/w) and temperature 210oC. Lactide was characterized by using fourier-transform infrared (FT-IR) spectroscopy and proton nuclear magnetic resonance (1HNMR). From 1H NMR analysis, optical purity of lactide produced in depolymerization process confirmed to be L�lactide and no stereoform of racemic formed. Temperature and catalyst concentration did not influence to stereoform of lactide but it affected to L-lactide concentration in crude lactide produced. The highest L-lactide concentration obtained in this study was 81.03%.

Item Type: Article
Subjects: T Technology > TP Chemical technology
Divisions: 03-Fakultas Teknik > 24201-Jurusan Teknik Kimia
03-Fakultas Teknik
Depositing User: Dr. Rahmayetty Rahmayetty
Date Deposited: 26 May 2023 10:50
Last Modified: 26 May 2023 10:50

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