Search

A Ser105Ala mutant of the lipase B from Candida antarctica enables 'perhydrolase-only' reactions. At the example of the chemoenzymatic Baeyer-Villiger oxidation of cyclohexanone, we demonstrate that with this mutant selective oxidation can be achieved in deep eutectic solvent while essentially eliminating the undesired hydrolysis reaction of the product. [ABSTRACT FROM AUTHOR]

Orange juice is a kind of fruit juice with huge market share. The most common adulteration is the addition of mandarin juice and grapefruit juice. Therefore, it is necessary to develop a method that can simultaneously detect mandarin and grapefruit components in orange juice. In this study, the specific site of the trnL-trnF gene of mandarin and the specific site of the accD-psaI gene of grapefruit were used for digestion and capillary electrophoresis separation to establish a duplex PCR–RFLP–CE method of simultaneous detection of mandarin and grapefruit components. By this method, the detection limits of mandarin and grapefruit components were 5% and 2.5%, respectively. About the specificity, only the 83–177 bp amplified bands of mandarin and grapefruit were specifically digested, while none of them were cut in the 8 kinds of fruits such as pear, apple, peach, papaya, pineapple, hawthorn, grape and banana. Duplex PCR–RFLP–CE tests were performed on the 8 commercially available fruit juices. As a result, grapefruit components were found in orange juice (C5) and other ingredients to be identified in grapefruit juice (C8). The established duplex PCR–RFLP–CE method can provide an effective detection method for orange juice adulteration in the future. [ABSTRACT FROM AUTHOR]

Homogeneous dual-ligand zinc complex catalysts was developed for the synthesis of propylene carbonate (PC) through chemical fixation of CO. It was found that among a number of various p K N-donor ligands, the catalytic performance was enhanced dramatically and the corrosion of the reaction system was effectively inhibited when 1-methylimidazol (1MI) was used as the N-donor ligand, in which >90 % PC yield could be obtained under mild reaction conditions. The dual-ligand zinc complex catalysts were characterized by various spectroscopic techniques such as FT-IR and HNMR. X-ray crystallography showed that the Zn(II) atom was coordinated in tetrahedron geometry by three bromine atom, one 1MI nitrogen atom, and one crystallographically independent cation to give a 3D tetrahedron structure, which forms tetracoordinated complexes. The structure of the complex gives the reasons for the enhancement of the catalytic activity from the microscopic molecular structure point of an extremely long and therefore labile Zn-Br bond, the diversification of the bond angles, and the interplay between the steric hindrance, which have great influence on the interaction forces of Zn-Br. Graphical Abstract: [Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]