Junying Fu

Catalytic Hydrotreatment of Fatty Acid Methyl Esters to Diesel‐like Alkanes Over Hβ Zeolite‐supported Nickel Catalysts

A Ni/Hβ zeolite catalyst was prepared for the selective transformation of fatty acid methyl esters (FAMEs) into diesel‐like alkanes through hydrotreatment. Characterization of the physicochemical properties of a 10 wt % nickel‐loaded, Hβ zeolite support indicated that nickel(II) oxide aggregated into large particles approximately 23.9 nm in size, whereas nickel aggregated into particles 18.3 nm in size, significantly increasing the total acid sites of Hβ zeolite after hydrogen reduction. The reaction scheme of the whole FAME transformation was investigated by using a batch reactor. It was found that FAMEs were first hydrogenated mainly to saturated fatty acids, followed by hydrodeoxygenation without carbon loss, the main route toward alkanes. The hydrotreatment of FAMEs by decarboxylation or decarbonylation was favored at high temperatures and low hydrogen pressures on Hβ zeolite with higher nickel loadings. The metallic and acidic functionalities of nickel/Hβ zeolite catalysts exhibited a synergistic effect in hydrodeoxygenation without carbon loss, achieving high FAME conversion and yields of liquid C16 and C18 alkanes. Optimal catalytic performances were obtained with 10 wt % nickel loading over Hβ zeolite (Si/Al=25) at 270 °C with a pressure of 1.0 MPa H2 over 8 h. A maximum alkane product yield of 93.2 % was achieved for C15–C18 alkanes with complete FAME conversion. 80.3 % FAME conversion could was achieved after eight reaction cycles by using the nickel/Hβ zeolite catalyst with calcination after every use.

Double-lipase catalyzed synthesis of kojic dipalmitate in organic solvents

Kojic dipalmitate(KDP) was synthesized by the way of esterification of palmitic and kojic acids in organic solvent, with double-lipase as the biocatalyst. Four commercially available lipases(Amano PS, Novozym 435, Lipozyme TL IM and Lipozyme RM IM) were used to group six double-lipase combinations. These combinations were studied and Amano PS-Novozym 435 was found to have the best efficiency and was selected for optimizing the reaction conditions. The optimal reaction conditions were that the mass ratio of Amano PS to Novozyme 435 1:1.5, stirring speed of 500 r/min, substrates molar ratio of 1:2, 50 °C, 5%(mass fraction) catalyst dosage of kojic acid quantity and using acetone as co-solvent. Under these conditions, the diesterification of C5 and C7 hydroxyl groups of kojic acid molecule could be well catalyzed by double-lipase and realize a high KDP yield of 85%.

Novel Sanger’s Reagent-like Styrene Polymer for the Immobilization of Burkholderia cepacia Lipase

Sangers reaction, which was originally developed for amino acid detection, was utilized for enzyme immobilization. The newly synthesized polymer support, which was called polymer NO2-4-fluorostyrene-divinylbenzene (pNFD), was embedded with a Sangers reagent-like functional group for immobilizing enzymes covalently under mild reaction conditions. Using Burkholderia cepacia lipase (BCL) as the target enzyme, the immobilization efficiency and activity of pNFD-BCL reached as high as 1.2 mg·g-1 and 33.21 U·g-1 (a specific activity of 27 675 U·g-1), respectively, realizing 90% activity recovery. It also improved the optimal reaction temperature of BCL from 40 to 65 °C, under which its full activity could be retained for 4 h. The new carrier also widened the pH-adaptive range of BCL as 6.5-10.0, allowing the lipase to operate normally in weak acid environment. Reusability of pNFD-BCL was significantly improved as almost no activity and/or enantioselectivity loss was observed in 200 h of triglyceride hydrolysis reaction and 17 batches of ( R, S)-1-phenylethanol resolution reaction.