Effect of Mg2+ on the catalytic activities of CoMgAl hydrotalcites in the selective oxidation of benzyl alcohol to benzaldehyde

A new method for removal of nitrogen in sewage sludge-derived hydrochar with hydrotalcite as the catalyst

The high content of nitrogen in hydrochar produced from hydrothermal carbonization (HTC) of sewage sludge (SS) leads to serious NOx pollution when the hydrochar is used as a solid fuel. Mg-Ga layered double hydroxides (LDHs), Mg-Al LDHs and their calcined samples (layered double oxides, LDO) were prepared. The LDHs and LDO all can notably promote the removal of nitrogen element, in which organic-N was transferred to NH₄⁺-N to cause increasing pH value. Mg-Al LDO showed the highest efficiency for the removal of nitrogen among the catalysts. The thermal decomposition of the N-organic matter with acidic sites in catalyst was the key step to release NH₃. The key role of basic sites in Mg-Al LDO was that it can effectively destroy the cell wall and extracellular polymeric substances structure. The lipid-like substance did not participate in the carbonization reaction, but they can be absorbed by the hydrochar. Partial SS floc directly transformed to hydrochar according to "solid-solid" reaction. The reaction pathways of remove nitrogen were proposed.

Selective Catalytic Oxidation of Benzyl Alcohol to Benzaldehyde by Nitrates

In this paper, ferric nitrate was used to oxidize benzyl alcohol in a mild condition and demonstrated its better performance compared to HNO₃. In the reaction, the conversion rate and product selectivity could be both as high as 95% in N₂ atmosphere, while the benzaldehyde yield also reached 85% in air. Similar to Fe(NO₃)₃·9H₂O, the other metallic nitrates such as Al(NO₃)₃·9H₂O and Cu(NO₃)₂·3H₂O could also oxidize the benzyl alcohol with high activity. The applicability of Fe(NO₃)₃·9H₂O for other benzylic alcohol was also investigated, and the reaction condition was optimized at the same time. The results showed the Fe(NO₃)₃·9H₂O would be more conducive in oxidizing benzyl alcohol under the anaerobic condition. The experiments in N₂ or O₂ atmospheres were conducted separately to study the catalytic mechanism of Fe(NO₃)₃. The results showed the co-existence of Fe³⁺ and NO3- will generate high activity, while either was with negligible oxidation property. The cyclic transformation of Fe³⁺ and Fe²⁺ provided the catalytic action to the benzyl alcohol oxidation. The role of NO3- was also an oxidant, by providing HNO₂ in anaerobic condition, while NO3- would be regenerated from NO in aerobic condition. O₂ did not oxidize the benzyl alcohol conversion directly, while it could still be beneficial to the procedure by eliminating the unwelcome NO and simultaneously reinforcing the circulation of Fe²⁺ and Fe³⁺, which therefore forms a green cyclic oxidation. Hence, the benzyl alcohol oxidation was suggested in an air atmosphere for efficiency and the need of green synthesis.

Hydrogen Peroxide as a Green Oxidant for the Selective Catalytic Oxidation of Benzylic and Heterocyclic Alcohols in Different Media: An Overview

Among a plethora of known and established oxidant in organic chemistry, hydrogen peroxide stands in a special position. It is commercially and inexpensively available, highly effective, selective, and more importantly it is compatible with current environmental concerns, dictated by principles of green chemistry. Several chemicals or their intermediates that are important in our daily life such as pharmaceuticals, flavors, fragrances, etc. are products of oxidation of alcohols. In this review, we introduce hydrogen peroxide as an effective, selective, green and privileged oxidant for the catalyzed oxidation of primary and secondary benzylic and heterocyclic alcohols to corresponding carbonyl compounds in different media such as aqueous media, under solvent-free conditions, various organic solvent, and dual-phase system.

Highly efficient Ni–Co oxide nanoparticles on nitrogen-doped FDU-15 for aerobic benzyl alcohol oxidation

Transition bimetal (Ni, Co) oxide nanoparticles immobilized onto nitrogen-doped FDU-15 are high active and show excellent selectivity to the benzaldehyde for the oxidation of benzyl alcohol.

Efficient catalytic oxidation of alcohol to carbonyl compounds over CoFe hydrotalcites

A series of CO₃²⁻–Co_xFe–LDHs (x = 2, 3, 4 and 5) compounds with different Co/Fe ratios have been prepared, characterized and introduced into the selective oxidation of alcohols by tert-butylhydroperoxide.

Hydrophilic sulfonic acid-functionalized micro-bead silica for dehydration of sorbitol to isosorbide

The large pore diameter and hydrophilic surface of SA-SiO₂-60.5 are beneficial to sorbitol adsorption and isosorbide desorption, and inhibit the deposition of coke.