Effect of Alkali Carbonate/Bicarbonate on Citral Hydrogenation over Pd/Carbon Molecular Sieves Catalysts in Aqueous Media

The efficient citral hydrogenation was achieved in aqueous media using Pd/CMS and alkali additives like K2CO3. The alkali concentrations, reaction temperature and the Pd metal content were optimized to enhance the citral hydrogenation under aqueous media. In the absence of alkali, citral hydrogenation was low and addition of alkali promoted to ~92% hydrogenation without reduction in the selectivity to citronellal. The alkali addition appears to be altered the palladium sites. The pore size distribution reveals that the pore size of these catalysts is in the range of 0.96 to 0.7 nm. The palladium active sites are also quite uniform based on the TPR data. The catalytic parameters are correlated well with the activity data.

Electrochemical manufacturing of nanocarbons from carbon dioxide in molten alkali metal carbonate salts： roles of alkali metal cations

One simple and fast way to manufacture a useful product from CO2 is to capture the gas by, and then carry out electrolysis in molten alkali metal carbonates. Carbon electro-deposition in molten Li2CO3-Na2CO3- KaCO3 （molar ratio： 43.5：31.5：25.0） has been widely reported in literature. However, studies in each of the individual alkali metal carbonates either have received less attention or are simply lacking in literature. Electrochem- ical studies of these molten carbonates are important to understand their underlying processes and reactions during the electrolysis. In this work, cyclic voltammograms （CVs） were recorded in each of the above-mentioned molten alkali carbonate salts using a 0.25 mm diameter Pt wire working electrode. In molten Na2CO3 and K2CO3, the main cathodic reaction was likely the formation of alkali metal, while that in Li2CO3 was carbon deposition. The results also suggest that other competing reactions such as CO and alkali metal carbide formation are possible as well in dif- ferent molten salts. On the CVs, the anodic current peaks observed are mostly associated with the oxidation of cathodic products. Flake/ring/sheet-like structures and quasi-spherical particles were observed in the produced carbon. The morphology of the carbon contained both amorphous and graphitic structures, which varied with different electrolysis variables.

Experimental on C50 Ultra-high-early Strength Concrete

In this paper,C50 ultra-high-early-strength concrete was prepared with rapid-harden sulphoaluminate cement,alkali carbonate early strength agent,inorganic tribasic acid retarder and polycarboxylate water reducing agent. The properties testing results of C50 ultra-high-early-strength concrete indicated that the compressive strength at 12 h exceeded 37 MPa and at 3 d exceeded 59 MPa. Compared to the C50 ordinary reference concrete,the durability of C50 ultra-high-early strength concrete was investigated. The results indicated that C50 ultra-high-early-strength concrete had the same chloride ion permeability resistance,carbonization resistance and abrasion resistance to the C50 ordinary concrete. As to the sulfate resistance,the ultra-high-early-strength concrete was much better than the ordinary concrete.