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Enantioselective synthesis of (-)-menthyl acetate in a batch stirred tank reactor: effects of fed batch feeding strategy

Sarmidi, Mohamad Roji and Lim, Jinny Lay Poh and Ng, Tit Soo (2001) Enantioselective synthesis of (-)-menthyl acetate in a batch stirred tank reactor: effects of fed batch feeding strategy. Proceedings of The 15th Symposium of Malaysian Chemical Engineers SOMChE 2001 . pp. 472-476.

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Investigation involving enantioselective synthesis of chiral compounds catalysed by immobilised enzyme lipase is a viable option. In this study, acetic anhydride as an acylating agent was employed with (±)-menthol, a secondary alcohol in enantioselective synthesis of (-)-menthyl acetate in a fed batch reactor. (-)-menthyl acetate is an optically active flavour and fragrance compound. Molar ratio concentration of acetic anhydride to (±)-menthol is 1:4. The ratio of alcohol to acyl donor, acid anhydride to (±)-menthol was prepared at 15 mmole/L : 60 mmole/L in 25 ml n-heptane. The reaction was catalysed by commercially available immobilised enzyme lipase, chirazymeL-3, c. -f, C2 lyo from candida rugosa. The incorporation of a fed batch feeding system to the batch reactor configuration was investigated. The system was evaluated in terms of molar percentage yield and productivity. The reactions were carried out at 30°C in n-heptane and molar yield as high as 8.72% -29.57% were attained after 48 hours of reaction. This fed batch feeding system was thought able to minimise the hydrolysis of acetic anhydride. A high concentration of acetic anhydride in a batch reaction system is not a viable option since water present in the reaction mixture would promote the hydrolysis of acetic anhydride catalysed by the same enzyme. A fed batch feeding strategy of 12uL, 10uL, 8uL and 6uL produced the highest molar percentage yield with 29.57% of (-)-menthyl acetate formation and productivity of 0.00154mM/min. The enzyme loading used was only 40% from the actual equivalent amount.

Item Type:Article
Uncontrolled Keywords:Chiral compound, fed batch feeding strategy, immobilised enzyme lipase, (-)-menthyl acetate
Subjects:T Technology > T Technology (General)
Divisions:Chemical and Natural Resources Engineering
ID Code:5070
Deposited By: Norhani Jusoh
Deposited On:28 Jan 2008 08:29
Last Modified:01 Jun 2010 03:23

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