Study on the Development of High-Performance P-Mo-V Catalyst and the Influence of Aldehyde Impurities on Catalytic Performance in Selective Oxidation of Methacrolein to Methacrylic Acid

A series of KxH1.1-xCu0.2Cs1(NH4)1.5PVMo11O40 (KxCuCsNH4PVA) catalysts with different x values were synthesized to catalyze the selective oxidation of methacrolein (MAL) to methacrylic acid (MAA). The effects of potassium (K) ions on both the structure and catalytic activity were studied in detail. The optimum K0.6CuCsNH4PVA exhibited a large surface area, more acid sites, and abundant active species (V4+/VO2+) in the secondary structure of the Keggin structure, consequently offering good catalytic performance. Furthermore, K ions increased the MAA selectivity at the expense of carbon monoxide and carbon dioxide (together defined as COX). Additionally, several process parameters for MAL oxidation were evaluated in the processing experiments. The effects of aldehyde impurities (formaldehyde and propanal) on the catalytic performance were investigated. Possible detrimental effects (catalyst poisoning and structural damage) of aldehyde impurities were excluded. A light decrease in MAL conversion could be attributed to the competitive adsorption of aldehyde impurities and MAL on the catalyst. Hopefully, this work contributes to the design of stable and feasible catalysts for the industrial production of MAA

Piperazine polypyrophosphat-halloysite nanotubes-melamine cyanurate synergistic flame retardant epoxy resin

By improving the existing preparation methods, a piperazine polypyrophosphat (PAPP) with high thermal stability was synthesized. It was compounded with halloysite nanotube (HNTs) and melamine cyanurate (MCA) to form P-N-Si intumescent flame retardant, and was used in synergistic flame retardant epoxy resin (EP). The effect of intumescent flame retardant on the flame retardancy of EP was investigated by means of limiting oxygen index, vertical combustion, cone calorimeter and SEM etc. The results show that the introduction of the compound flame retardant forms a dense and continuous intumescent carbon layer, which improves the flame retardant efficiency of the epoxy resin in the condensed phase and the gas phase. It reduces the heat release and heat release rate of epoxy resin and the toxic gases release effectively. When the PAPP/HNTs/MCA ratio is 7∶1∶2, the limiting oxygen index of flame retardant resin reaches 34.3%, the UL-94 vertical combustion test reaches V-0 level. Compared with pure EP, the amount of residual carbon is increased significantly, the peak heat release rate (HRR) is decreased by 60.56%, and the total heat release (THR) and toxic gas emissions are reduced significantly for modified EP. In addition, the thermogravimetric analysis results suggest that the initial decomposition temperature of flame retardant modified EP is decreased by 4.4% (ΔT), and the modified EP still has high thermal stability

Additional file 1: Tabel S1. of Complete genome analysis of a novel recombinant isolate of pepper veinal mottle virus from mainland China

Primers used in this study. Table S2. Complete genome sequences quoted in this article. (DOC 64 kb