Purification of Lactic Acid via Esterification of Lactic Acid Using a Packed Column, Followed by Hydrolysis of Methyl Lactate Using Three Continuously Stirred Tank Reactors (CSTRs) in Series: A Contin

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• 作者：Sanjay P. Kamble ; Prashant P. Barve ; Jyeshtharaj B. Joshi ; Imran Rahman ; Bhaskar D. Kulkarni
• 刊名：Industrial & Engineering Chemistry Research
• 出版年：2012
• 出版时间：February 1, 2012
• 年：2012
• 卷：51
• 期：4
• 页码：1506-1514
• 全文大小：893K
• 年卷期：v.51,no.4(February 1, 2012)
• ISSN：1520-5045

文摘

The world market of lactic acid is growing every year, mainly as a solvent and precursor to poly(lactic acid) (PLA). The cost of renewable biomass-derived PLA will have to compete with other synthetic polymers, if it is to grab a significant and sustainable fraction of the market share. It is thus necessary to have efficient and cost-effective technology for the production of pure-grade lactic acid (LA). In this article, a novel cost-effective, eco-friendly continuous process for the production of high-quality lactic acid at pilot plant scale has been demonstrated. The novelty of this process is that, for the first time, we report and use the concept of inverse reactive distillation for the esterification of crude concentrated LA in a continuous countercurrent packed column mode. This allows us to operate the column at higher temperatures, improving the kinetic rate process and leading to shorter columns. This is followed by the hydrolysis of methyl lactate (MLA) in a series of three continuously stirred tank reactors (CSTRs), where LA itself acts as a catalyst. The LA obtained in the pilot plant process shows 99.81% purity (by weight) on water-free basis and has an optical purity of 99.9%. The pilot scale experimental results pertaining to the autocatalytic esterification of LA and hydrolysis of MLA have been compared and validated, with respect to simulated results. The innovations reported here can make the process economically viable for commercial use.