Interaction between Pd and Cu nanoparticles in bimetallic CuPdx nanoparticles and its impact on oxidation of 1,2-propanediol to aliphatic acids

Bimetallic CuPdx nanoparticles synthesized by the wet chemical reduction method were used as the catalysts in the catalytic oxidation of 1,2-propanediol with gaseous oxygen to aliphatic acids.The palladium and copper nanoparticles in the bimetallic CuP dxnanoparticles had an alloying trend.The catalytic activity of the palladium nanoparticles in the bimetallic CuP dxnanoparticles was enhanced by the interaction between the palladium and copper nanoparticles.When the bimetallic CuPd7 nanoparticles catalyzed the oxidation of 1,2-propanediol in an alkaline aqueous solution at 100℃for 3h,lactic,formic,and acetic acids were dominantly produced with the total selectivity of above 99%at the 1,2-propanediol conversion of 85.9%.The simulation of the reaction kinetic equation on the CuPd7 catalyst showed that the reaction activation energy was 29.4kJ·mol^-1,indicating that the bimetallic CuPd7 nanoparticles had a high catalytic activity in the oxidation reaction between 1,2-propanediol and gaseous oxygen.

Silver-catalyzed decarboxylative C-H functionalization of cyclic aldimines with aliphatic carboxylic acids

Silver-catalyzed decarboxylative C–H alkylation of cyclic aldimines with abundant aliphatic carboxylic acids has been realized under mild reaction conditions generating the corresponding products in moderate to good yields(32%–91%).In addition,a gram-scale reaction,late-stage modification of drug,synthetic transformation of the product,and further application of the catalytic strategy were also performed.Preliminary studies indicate that the reaction undergoes a radical process.

离子排斥色谱用于厌氧消化处理的水中脂肪族羧酸的分析(英文)

The analysis of seven aliphatic carboxylic acids(formic,acetic,propionic,iso-butyric,n-butyric,iso-valeric and n-valeric acid) in anaerobic digestion process waters for biogas production was examined by ion-exclusion chromatography with dilute acidic eluents(benzoic acid,perfluorobutyric acid(PFBA) and sulfuric acid) and non-suppressed conductivity/ultraviolet(UV) detection.The columns used were a styrene/divinylbenzene-based strongly acidic cation-exchange resin column(TSKgel SCX) and a polymethacrylate-based weakly acidic cation-exchange resin column(TSKgel Super IC-A/C).Good separation was performed on the TSKgel SCX in shorter retention times.For the TSKgel Super IC-A/C,peak shape of the acids was sharp and symmetrical in spite of longer retention times.In addition,the mutual separation of the acids was good except for iso-and n-butyric acids.The better separation and good detection was achieved by using the two columns(TSKgel SCX and TSKgel Super IC-A/C connected in series),lower concentrations of PFBA and sulfuric acid as eluents,non-suppressed conductivity detection and UV detection at 210 nm.This analysis was applied to anaerobic digestion process waters.The chromatograms with conductivity detection were relatively simpler compared with those of UV detection.The use of two columns with different selectivities for the aliphatic carboxylic acids and the two detection modes was effective for the determination and identification of the analytes in anaerobic digestion process waters containing complex matrices.

Synthesis and Characterization of Methanesulfonate and Ethanesulfonate Intercalated Lithium Aluminum LDHs

LDH-phases become increasingly interesting due to their broad ability to be able to incorporate many different cations and anions. The intercalation of methanesulfonate and ethanesulfonate into a Li-LDH as well as the behavior of the interlayer structure as a function of the temperature is presented. A hexagonal P63/m [LiAl2(OH)6][Cl?1.5H2O] (Li-Al-Cl) precursor LDH was synthesized by hydrothermal treating of a LiCl solution with γ-Al(OH)3. This precursor was used to intercalate methanesulfonate (CH3O3S?) and ethanesulfonate (C2H5O3S?) through anion exchange by stirring Li-Al-Cl in a solution of the respective organic Li-salt (90?C, 12 h). X-ray diffraction pattern showed an increase of the interlayer space c' (d001) of Li-Al-methanesulfonate (Li-Al-MS) with 1.2886 nm and Li-Al-ethanesulfonate (Li-Al-ES) with 1.3816 nm compared to the precursor with 0.7630 nm. Further investigations with Fourier-transform infrared spectroscopy and scanning electron microscopy confirmed a complete anion exchange of the organic molecules with the precursor Cl?. Both synthesized LDH compounds [LiAl2(OH)6]CH3SO3?nH2O (n = 2.24-3.72 (Li-Al-MS) and [LiAl2(OH)6]C2H5SO3}?nH2O (n = 1.5) (Li-Al-ES) showed a monomolecular interlayer structure with additional interlayer water at room temperature. By increasing the temperature, the interlayer water was removed and the interlayer space c' of Li-Al-MS decreased to 0.87735 nm (at 55?C). Calculations showed that a slight displacement of the organic molecules is necessary to achieve this interlayer space. Different behavior of Li-Al-ES could be observed during thermal treatment. Two phases coexisted at 75?C - 85?C, one with a reduced c' (0.9015 nm, 75?C) and one with increased c' (1.5643 nm, 85?C) compared to the LDH compound at room temperature. The increase of c' is due to the formation of a bimolecular interlayer structure.

Synthesis and properties of polybenzazoles containing flexible methylene in backbone

A novel series of polybenzazoles with rigid-rod benzoxazole cycle and soft methylene segment was designed and synthesized via solution condensation poly-merizations from 4,6-diamino-l,3-benzenediol dipho-sphate,terephthalic acid and aliphatic dicarboxylic acid.The structures of polybenzazoles were characterized by means of FT-IR,1H NMR and Wide-angle X-ray diffrac-tion(WAXRD).All the polymers show excellent thermal stability and the TdS was above 471℃,The intrinsic vis-cosities[η]of the polymers ranged from 0.8 to 0.9.The UV-Vis absorption peaks of the polymers in MSA were blue-shifted from 429 nm for PBO to 291 nm for PBOC7,and the Stokes shifts in PL spectra enlarged.