7 results about "Over oxidation" patented technology

The application discloses a preparation method of aromatic aldehyde by oxidizing aromatic hydrocarbon, and the method comprises the following steps: contacting a solution containing aromatic hydrocarbon with a supported catalyst under an oxygen-containing atmosphere, and reacting to obtain the aromatic aldehyde; the reaction is carried out in a fixed bed photocatalytic reaction device; and the supported catalyst is a TiO2 surface supported oxide catalyst. The fixed bed reaction device can keep the activity of the target reaction and the high selectivity of the product for a long time, and effectively overcomes the problem of excessive oxidation of the product.

This invention discloses a method for the selective oxidation of methane to oxygen-containing compounds using water as the oxidant. The method employs orthorhombic molybdenum trioxide as the sole catalyst and water as the sole oxidant, allowing methane to react with water in a closed reaction system, resulting in the directional conversion to oxygen-containing compounds. This method eliminates the need for added precious metal catalysts, hydrogen peroxide, or oxygen as external oxidants, and avoids the use of co-catalysts, co-reactants, or reducing agents such as carbon monoxide or hydrogen. The selective oxidation of methane is achieved solely with water and orthorhombic molybdenum trioxide, simplifying the reaction system composition. Furthermore, the preparation process is simple and inexpensive, reducing catalyst costs and oxidant safety risks, while simultaneously achieving the directional conversion of methane to oxygen-containing compounds. This invention solves the problems of high oxidant costs and complex processes caused by co-reactants in existing technologies, and eliminates the generation of excessive CO or CO2 oxidation products.

This invention relates to a catalyst for photothermal catalytic methane coupling reaction, its preparation method, and its application. The catalyst comprises a titanium dioxide support and metal particles; the titanium dioxide support has anatase phase crystal structure; the metal particles, based on 100% of the total mass of the catalyst, have a mass percentage content greater than 0 and less than or equal to 0.12 wt%; the metal element in the metal particles is selected from Pd or Pt; the metal particles are loaded onto the titanium dioxide support via photodeposition, specifically: under an inert gas atmosphere, using methanol as a sacrificial agent, photogenerated electrons are used to reduce metal ions to zero-valent metal atoms in situ, which are then deposited on reduction sites on the surface of the titanium dioxide support. This invention's catalyst, by controlling the support crystal structure and metal-support interface, achieves efficient conversion of methane to ethane under mild conditions, avoiding over-oxidation, and exhibits excellent catalytic activity and stability.

This invention belongs to the field of pharmaceutical chemical synthesis technology and relates to a method for the catalytic oxidation of acetate tetraenes to synthesize dihydroxy compounds. The method uses acetate tetraenes as a raw material, acetone as a solvent, Ru-X-Y as a catalyst, and sodium hypochlorite as an oxidant. Under alkaline conditions, catalytic oxidation yields the product dihydroxy compound. In Ru-X-Y, X is Pt or Pd, and Y is any one of Fe, Mn, and Cu. This invention uses solid Ru-X-Y as a catalyst, utilizing the synergistic activation and polarization properties of metals. It only requires sodium hypochlorite, which has relatively weak oxidizing power, as an oxidant to catalytically oxidize acetate tetraenes to the target product dihydroxy compound, effectively avoiding the use of strong oxidants such as potassium permanganate. This not only prevents over-oxidation and improves product yield and quality but also increases production efficiency, resulting in significant economic and social benefits.

The application discloses a kind of hierarchical porous carbon materials and preparation method and its application in preparation N-C-N bond containing compound for preparation.The hierarchical porous carbon material of the application includes Zn-N3 single atom and nitrogen-doped carbon skeleton, and the Zn-N3 single atom is supported on the nitrogen-doped carbon skeleton;The nitrogen-doped carbon skeleton includes three-dimensional open ordered hierarchical porous structure, and the hierarchical porous structure includes at least 2 or 3 of macropore, mesopore and micropore.The hierarchical porous carbon material of the application has highly dispersed Zn-N3 single atom, which can provide moderate catalytic activity, avoid alcohol, amine excessive oxidation and other side reactions, so as to efficiently synthesize N-C-N bond containing compound.

A method for preparing a copper-based NH3 oxidation and purification catalyst using atomic layer deposition (ALD) technology is disclosed, relating to the field of environmental catalysis. Using mesoporous materials such as Al / SBA-15 as supports, copper is loaded as the active component via ALD to obtain the catalyst. The resulting catalyst exhibits extremely high specific surface area and uniform pore size distribution, which is beneficial for the dispersion of copper active species and greatly optimizes the mass transfer and diffusion between reactants and products. This catalyst is applied to the selective catalytic oxidation of ammonia, utilizing its unique copper species ([Cu-O-Cu)). 2+ This effectively prevents ammonia from being over-oxidized at high temperatures, thus improving the N2 selectivity of the target product. The catalyst disclosed in this invention achieves 100% NH3 conversion and over 90% N2 yield within a temperature range of 350-400℃.