Directing the Simultaneous Conversion of Hemicellulose and Cellulose in Raw Biomass to Lactic Acid

Abstract

The production of lactic acid (LaA) directly from actual biomass via a one-step reaction without pretreatment by chemocatalysis has shown high potential for satisfying its enormous demand in widespread applications. Here, we developed an integrated catalytic strategy using Y­(III) as the catalyst, enabling the simultaneous conversion of hemicellulose and cellulose components in the actual biomass and selectively yielding LaA with a yield up to 66.3%. The evaluated turnover frequency was 9.7 h–1, the highest value using the actual biomass as the feedstock as far as we know. Combining the result of the experiment with density functional theory studies, we revealed that in the present system, H+, [Y­(OH)2(H2O)2]+ species derived from Y3+ hydrolysis cooperatively contributed to the production of LaA. H+ was primarily responsible for the selective fractionation of hemicellulose and cellulose from actual lignocelluloses to soluble polysaccharide fragments as well as the next polysaccharide conversion to the monosaccharide. [Y­(OH)2(H2O)2]+ species predominantly contributed to the next monosaccharide conversion to LaA, particularly favoring the electron outflow from C3 to C4–O of fructose derived from glucose isomerization and leading to the accumulation of electronic density on the O atom in C4–O, thereby significantly weakening the C3–C4 bond and directing the selective cleavage of the C3–C4 bond in fructose to LaA. This work might provide a potential strategy for the simultaneous conversion of C5 and C6 sugars in the actual biomass selectively yielding LaA in a cost-effective and environment-friendly way.

A highly efficient rod-like-CeO2-supported palladium catalyst for the oxidative carbonylation of glycerol to glycerol carbonate

“…As biodiesel is produced on a large scale, the use of GL has become an important factor affecting the development of the biodiesel industry. GL can be converted into valuable chemicals by reaction, such as acrolein, 3 glycerol ether, 4 1,2-propanediol, 5 lactic acid, 6,7 and glycerol carbonate (GLC). 8 GLC is an important derivative of GL with a high boiling point, high biodegradability, low ammability, and low toxicity.…”

Rare‐Earth Metal Yttrium‐Modified Composite Metal Oxide Catalysts for High Selectivity Synthesis of Biomass‐Derived Lactic Acid from Cellulose

“…Interestingly, physical mixture of γ‐Al 2 O 3 with Y 2 O 3 as catalyst resulted in a substantially enhanced lactic acid yield of 63.7 % under identical conditions (Table 2, entry 7), which was far higher than that of the individual compound, suggesting that both Y 2 O 3 and γ‐Al 2 O 3 were the essential active sites for the efficient production of lactic acid from cellulose [16a] . As expected, the Y 2 O 3 /Al 2 O 3 gave significantly enhanced lactic acid yield than that of physical mixture of Y 2 O 3 and γ‐Al 2 O 3 , indicated that modification of Y on the γ‐Al 2 O 3 can efficiently inhibited the production of by‐product such as HMF, mainly due to generating new Lewis acid sites and Brønsted acid sites as a result of the interaction between yttrium species and γ‐Al 2 O 3 in internal catalyst, they were cooperative in promoting the hydrolysis of cellulose, isomerization of glucose, and the selective cleavage of C3‐C4 bond of soluble oligosaccharides via retro‐aldol condensation reaction, consequently leading to the formation of lactic acid [18b] . Besides, we intentionally reduced the content of Y with 5wt.…”

Laser‐assisted preparation of monolithic acidic catalysts for biomass conversion

“…2 For example, monomers produced from various types of biomass can be used to synthesize degradable plastics, which beneficially reduces white matter pollution. 5-(Hydroxymethyl)furfural (5-HMF) is a vital platform molecule that can be used as a raw material to synthesize 2,5-furandicarboxylic acid, 3 2,5-bis(hydroxymethyl)furan, 4 dimethylfuran, 5 adipic acid, 6 hexanediol, 7 levulinic acid, 8 and other fine chemical raw materials. Biomass is the most economical feedstock for the production of 5-HMF.…”