Facile Production of 2,5-Furandicarboxylic Acid via Oxidation of Industrially Sourced Crude 5-Hydroxymethylfurfural.

The oxidation of 5-hydroxymethylfurfural (HMF) produces value-added chemicals such as 2,5-diformylfuran (DFF) and 2,5-furandicarboxylic acid (FDCA). In this work, FDCA production was achieved by oxidation of crude HMF solution containing around 45 % HMF and unwanted byproducts such as 5,5'-[oxy-bis(methylene)]bis-2-furfural (HMF dimer) and polymers. At optimized reaction conditions similar to the Mid-Century process, homogeneous oxidation of the crude HMF (up to 20 wt% in the feed) by Co/Mn/Br catalyst in acetic acid solution produced FDCA at >95 % yield.

Beyond ketonization: selective conversion of carboxylic acids to olefins over balanced Lewis acid-base pairs.

We report the direct conversion of mixed carboxylic acids to C-C olefins with up to 60 mol% carbon yield through cascade (cross) ketonization, (cross) aldolization and self-deoxygenation reactions. Co-feeding hydrogen provides an additional ketone hydrogenation/dehydration pathway to a wider range of olefins.

Key Roles of Lewis Acid-Base Pairs on ZnxZryOz in Direct Ethanol/Acetone to Isobutene Conversion.

The effects of surface acidity on the cascade ethanol-to-isobutene conversion were studied using ZnxZryOz catalysts. The ethanol-to-isobutene reaction was found to be limited by the secondary reaction of the key intermediate, acetone, namely the acetone-to-isobutene reaction. Although the catalysts with coexisting Brønsted acidity could catalyze the rate-limiting acetone-to-isobutene reaction, the presence of Brønsted acidity is also detrimental.

Direct Determination of Glycidyl Esters of Fatty Acids in Vegetable Oils by LC-MS.

An LC-MS method using a single quadrupole mass spectrometer was developed for direct analysis of glycidyl esters of fatty acids in vegetable oils. Without any sample clean-up, this method provided acceptable recovery of seven glycidyl esters, comparable results to a previously-published method utilizing two solid-phase extraction steps, and consistent detection parameters after greater than 200 injections without any cleaning operations performed. This method could readily be implemented as a screening assay for glycidyl esters in most oil laboratories.

Direct Determination of MCPD Fatty Acid Esters and Glycidyl Fatty Acid Esters in Vegetable Oils by LC-TOFMS.

Analysis of MCPD esters and glycidyl esters in vegetable oils using the indirect method proposed by the DGF gave inconsistent results when salting out conditions were varied. Subsequent investigation showed that the method was destroying and reforming MCPD during the analysis. An LC time of flight MS method was developed for direct analysis of both MCPD esters and glycidyl esters in vegetable oils.

Aldehyde oxidoreductase as a biocatalyst: Reductions of vanillic acid.

Aldehyde oxidoreductase (carboxylic acid reductase) catalyzes the Mg(2+), ATP and NADPH dependent reduction of carboxylic acids to their corresponding aldehydes. The identification of the gene from Nocardia sp. NRRL 5646 and its expression in E.

Reduction of carboxylic acids by Nocardia aldehyde oxidoreductase requires a phosphopantetheinylated enzyme.

Aldehyde oxidoreductase (carboxylic acid reductase (Car)) catalyzes the magnesium-, ATP-, and NADPH-dependent reduction of carboxylic acids to their corresponding aldehydes. Heterologous expression of the car gene in Escherichia coli afforded purified recombinant enzyme with a specific activity nearly 50-fold lower than that of purified native Nocardia sp. enzyme.