Chemocatalytic Production of Lactates from Biomass-Derived Sugars

Heng Zhang,Hu Li,Jian He,Song Yang,Yulin Hu,Liying Qi

doi:10.1155/2018/7617685

Heng Zhang, Hu Li + Show 4 more

Open Access

https://doi.org/10.1155/2018/7617685

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Abstract

In recent decades, a great deal of attention has been paid to the exploration of alternative and sustainable resources to produce biofuels and valuable chemicals, with aims of reducing the reliance on depleting confined fossil resources and alleviating serious economic and environmental issues. In line with this, lignocellulosic biomass-derived lactic acid (LA, 2-hydroxypropanoic acid), to be identified as an important biomass-derived commodity chemical, has found wide applications in food, pharmaceuticals, and cosmetics. In spite of the current fermentation of saccharides to produce lactic acid, sustainability issues such as environmental impact and high cost derived from the relative separation and purification process will be growing with the increasing demands of necessary orders. Alternatively, chemocatalytic approaches to manufacture LA from biomass (i.e., inedible cellulose) have attracted extensive attention, which may give rise to higher productivity and lower costs related to product work-up. This work presents a review of the state-of-the-art for the production of LA using homogeneous, heterogeneous acid, and base catalysts, from sugars and real biomass like rice straw, respectively. Furthermore, the corresponding bio-based esters lactate which could serve as green solvents, produced from biomass with chemocatalysis, is also discussed. Advantages of heterogeneous catalytic reaction systems are emphasized. Guidance is suggested to improve the catalytic performance of heterogeneous catalysts for the production of LA.

Highlights

Due to the burgeoning world population, demands for energy and chemicals are sharply increasing. erefore, traditional nonrenewable fossil resources, coal and petroleum, are going to be run out, and their concomitantly environmental and climatological impacts are urgently needed to be addressed in the meantime [1,2,3,4]
Versatile activated hydrotalcites were utilized as alkaline catalysts to convert glucose in a flow reactor into LA, giving 20.3% LA yield at 50°C [35]. e results indicated that hydrotalcite (Mg/Al 2) activated at 723 K contained the most Brønsted-base sites, and a linear increase was determined with respect to LA yield and accessible Brønstedbase sites
Catalytic transformations of valuable organic acids such as lactic acid, levulinic acid, and amino acid from renewable carbon resources including polysaccharides, lignin, and their derivatives is of high interest for a sustainable chemical industry in the future [126, 127]. e development of efficient techniques for commercial lactic acid and alkyl lactates production from lignocellulosic biomass is regarded as an important process of biorefinery, in order to reduce the reliance on petroleum feedstocks

Summary

Introduction

Due to the burgeoning world population, demands for energy and chemicals are sharply increasing. erefore, traditional nonrenewable fossil resources, coal and petroleum, are going to be run out, and their concomitantly environmental and climatological impacts are urgently needed to be addressed in the meantime [1,2,3,4]. Alternatively manners to transform renewable, sustainable, and carbon-neutral biomass resources from plants into potential biofuels, polymer building blocks, and value-added chemicals are widely researched. Sustainability issues regarding the up-scaling of the present fermentation process are highly required to be disposed via a promising alternative method, chemocatalysis, which could be regarded as the research hotspot in the state-of-the-art development of lactic acid research. In a platform approach, chemocatalysts are playing a vital role in the fundamental and novel production routes of lactic acid (or lactates), using sugars even real lignocellulosic biomass (i.e., cornstalk). E main emphasis of this review is to depict the state-of-the-art development of LA or lactates production from sugars and real lignocellulosic biomass resources, with chemocatalysis especially heterogeneously catalysts which have tremendous advantages (i.e., recyclable, reusable, and environmentally benign). Structure-function relationships, reaction mechanisms, and guidance on designing heterogeneous acid catalysts for LA or lactates production are discussed,

Chemocatalytic Production of LA

H Pyruvaldehyde

Production of Alkyl Lactates

Findings

Conclusion and Perspective