22 results about "Over oxidation" patented technology

The invention discloses nanometer graphene oxide and a preparation method thereof. The transverse size of the nanometer graphene oxide is 10-100 nm, and the thickness of the nanometer graphene oxide is 1-2.5 nm. The surface chemical structure meets the following conditions: a C1s peak is analyzed on the basis of X-ray photoelectron spectroscopy, the sum of the atomic percent content of hydroxyl and epoxy groups is not higher than 15%, and the atomic percent content of carboxyl is not lower than 6%. According to the structural design, the structural defect caused by excessive oxidation or reduction in a traditional method is avoided, and the chemical stability and the functionalization potential of the material are improved.

The invention discloses low-defect graphene oxide and a preparation method thereof.The preparation method comprises the steps of pre-expansion treatment, dilution treatment, stripping treatment, mild oxidation and post-treatment, and by means of a step-by-step cooperation strategy of pre-expansion, stripping and mild oxidation, mild pre-expansion of graphite is achieved in a concentrated sulfuric acid system through low-concentration hydrogen peroxide firstly, and then the graphite is subjected to post-treatment; and performing physical stripping to obtain few-layer graphene, performing mild oxidation under a low-temperature condition, and circularly using the filtrate collected in the dilution treatment stage for post-treatment washing. According to the method, the oxidation degree is effectively controlled, lamellar defects caused by excessive oxidation are avoided, and finally the low-defect graphene oxide with the C / O ratio larger than or equal to 10 is obtained; meanwhile, waste liquid recycling is achieved, the environment cost is reduced, the process steps are simple, reaction conditions are easy to control, industrial production is easy, and the method has wide application prospects in the fields of composite materials, energy storage devices and the like.

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.

The invention relates to the technical field of chemical industry, in particular to a method for preparing styrene by oxidative dehydrogenation of ethylbenzene, which comprises the following steps: under the condition of low temperature of 150-300 DEG C, ethylbenzene is contacted with an oxygen storage catalyst in an oxidation state, the catalyst catalyzes ethylbenzene dehydrogenation to generate styrene and hydrogen, and then the hydrogen is selectively oxidized into water by self lattice oxygen, directional movement of reaction balance is realized; the catalyst consuming lattice oxygen is regenerated through oxygen-containing gas flow to recover the oxidation state and is recycled. The oxygen storage catalyst is a composite metal oxide or carbide-oxide composite material with a specific structure, and has the functions of ethylbenzene activation, lattice oxygen storage and release and molecular oxygen activation. The invention also provides two reactor implementation schemes of fixed bed switching and fluidized bed circulation. The problems that traditional high-temperature dehydrogenation is high in energy consumption and limited in selectivity and existing oxidative dehydrogenation uses pure oxygen to cause safety and excessive oxidation are solved, and low-temperature, efficient and safe styrene production is achieved.

The present invention belongs to the technical field of organic synthesis, and relates to a supported catalyst, and the preparation thereof and the use thereof in a reaction of synthesizing methyl glyoxylate from methyl glycolate. The supported catalyst comprises a carrier, and an active metal component and an auxiliary component loaded on the carrier, wherein the active metal component is vanadium; and the auxiliary component is selected from at least one of silver, molybdenum, yttrium, bismuth, tungsten, manganese, niobium, zinc, zirconium, cerium, cobalt, magnesium, calcium, barium, lanthanum, boron, gallium, germanium, or indium. Compared with the prior art, the active metal and auxiliary of the catalyst prepared in the present invention are concentrated on the surface layer of the carrier and distributed in an eggshell form, and methyl glycolate is adsorbed, reacted and desorbed on the surface of the catalyst to avoid the generation of a large amount of over-oxidation products CO and CO2, thereby improving the yield of methyl glyoxylate.

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.

The invention provides a green and efficient preparation method of an anthelmintic albendazole sulfoxide, which is characterized in that water is used as a green oxygen source, an anodic oxidation reaction is driven by electric energy at room temperature, albendazole sulfoxide is synthesized with high selectivity, and sulfone by-products generated by excessive oxidation are effectively avoided. According to the method, albendazole, cheap electrolyte sodium bromide, dimethyl sulfoxide and water are mixed into homogeneous reaction liquid, inert gas protection is not needed, and the homogeneous reaction liquid is introduced into an electrochemical microchannel continuous reactor to achieve oxidation. Compared with a traditional hydrogen peroxide oxidation method and a low-temperature chemical oxidation method, the method does not need to use a stoichiometric oxidizing agent, is mild in reaction condition, effectively avoids related safety and environmental risks, meets the requirements of green and sustainable development, and has a good industrial application prospect.

The invention relates to the technical field of organic synthesis and preparation, in particular to a multi-step synthesis process for preparing o-trifluoromethyl benzoyl chloride from o-xylene, which comprises the following steps: oxidation preparation of o-toluic acid: adding o-xylene and a solvent into a reaction container, reacting under the action of an oxidation system, and separating to obtain o-trifluoromethyl benzoyl chloride; after the reaction is finished, carrying out post-treatment to obtain o-toluic acid; by optimizing the process for preparing o-toluic acid through oxidation, selecting an adaptive catalytic system and accurately regulating and controlling reaction conditions, the problems of low oxidation efficiency, more raw material residues and excessive oxidation in the existing process are effectively solved, the yield and purity of o-toluic acid are remarkably improved, a high-quality raw material is provided for subsequent steps, and the method is suitable for industrial production. The efficiency and the product quality of the whole preparation process are guaranteed from the source.

The invention belongs to the technical field of photocatalytic methane conversion, and particularly relates to a preparation method of a Keggin type heteropolyacid, AgNO3 and mesoporous TiO2 compounded photocatalyst and performance research of the Keggin type heteropolyacid, AgNO3 and mesoporous TiO2 compounded photocatalyst. The chemical expression formula of the photocatalyst is Ag-PW12 / TiO2. The preparation process adopts a one-step dipping-calcining method and comprises the following steps: S1, in the dipping process, firstly weighing a certain amount of TiO2, PW12 and AgNO3 (only changing the mass percent of AgNO3 and TiO2 between 0.5%, 1.0%, 1.5% and 2.5%), adding the weighed TiO2, PW12 and AgNO3 into 50ml of water, carrying out ultrasonic dispersion, stirring for 12 hours, washing with deionized water, filtering and collecting a sample; s2, drying the obtained material at 100 DEG C for 12 hours; and S3, heating the obtained material to 300 DEG C in a muffle furnace at a heating rate of 2 DEG C / min, maintaining the temperature of 300 DEG C for 3 hours, cooling to room temperature, and collecting a sample. A sample is marked as TWA-X, wherein X represents the mass percent value (0.5, 1.0, 1.5 and 2.5) of AgNO3 and TiO2. The photocatalyst for photocatalytic methane conversion is synthesized, and high yield and high selectivity of a liquid C1 oxygen-containing compound are realized on the basis of the catalyst.

The invention provides a heterogeneous catalyst COFBMTD-PY as well as a preparation method and application thereof, belongs to the technical field of photocatalysts, and can solve the problems that the current thioether oxidation reaction needs to be operated under a high-temperature condition, the dosage of the catalyst is large, an additional cocatalyst is needed, and in the actual use process, most of the catalysts cannot be recycled and are not easy to recover, so that the cost is low, and the like. The loss of the catalyst is serious, and the reaction waste is increased. The heterogeneous catalyst COFBMTD-PY disclosed by the invention is constructed by taking 1, 3, 6, 8-tetra-(p-aminophenyl)-pyrene and 2 ', 5'-bis ((1H-imidazole-1-yl) methyl)-[1, 1 ': 4', 1 ''-terphenyl]-4, 4''-diformaldehyde as units, and the heterogeneous catalyst COFBMTD-PY has a structural formula shown in the specification. The heterogeneous catalyst COFBMTD-PY disclosed by the invention can be applied to catalysis of oxidation reaction of methyl thioether and derivatives thereof, and has the advantages that efficient conversion of thioether is realized, reaction selectivity is precisely regulated and controlled, sulfone generation caused by excessive oxidation is avoided, a cocatalyst or extra oxygen is not needed, and the catalyst can be repeatedly utilized.

The invention discloses a method for oxidation removal and heavy metal toxicity inhibition of complex chromium in wastewater through iron-based secondary mineral mediated biological Fenton reaction and application. According to the method, Fenton reaction is induced through atmosphere regulation and control biological / mineral action, and oxidative degradation of complex-state chromium and heavy metal toxicity inhibition are achieved. The method comprises the following steps: reducing iron by facultative dissimilatory iron reducing bacteria and iron-based secondary minerals under anaerobic conditions; aeration is carried out, and accumulated ferrous iron and oxygen are utilized to initiate Fenton reaction so as to oxidize the organic complexing agent to realize complex breaking; converting to an anaerobic state, and reducing Cr (VI) generated by excessive oxidation; and circularly executing the aerobic / anaerobic operation until the wastewater reaches the standard. The method realizes advanced treatment of the complex chromium wastewater through a single reactor, and has the advantages of simple process, easily available materials and low operation cost.

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 invention discloses a method for synthesizing sulfoxide through selective oxidation of thioether under synergistic catalysis of enzyme and metal, and belongs to the technical field of pharmaceutical compound synthesis. The method comprises the following steps: firstly, artificially synthesizing a pyranose 2-oxidase encoding gene, and carrying out vector construction, heterologous expression and separation and purification to prepare a high-purity recombinase solution; and dissolving the thioether compound in a solvent in an oxygen atmosphere, adding D-glucose, FAD and a metal catalyst, adjusting the pH value of the system, and finally adding the recombinase liquid to obtain the sulfoxide product. According to the method, low-concentration hydrogen peroxide is mildly generated in situ, the problems of excessive oxidation, side reaction and the like are avoided, the product selectivity and yield are improved, and the production safety risk is reduced. The introduction of the sodium tungstate dihydrate further enhances the catalytic efficiency and selectivity, accelerates the reaction rate, widens the substrate range, and is mild in reaction condition, environment-friendly and in line with the development direction of green chemistry.

The present application belongs to the field of pearl processing, and relates to a pearl bleaching method based on phase transfer catalytic oxidation. Pearl grains are soaked in a potassium chlorate aqueous solution, cleaned, air-dried, and oven-dried. The oven-dried pearl grains are soaked in an 18-crown-6 alcohol organic solution, bleached until decolorization is complete, the pearl grains are removed, cleaned after being soaked in clean water, and dried to obtain finished products. The present application pre-permeates the oxidant potassium chlorate without oxidation capacity into the pearl layer and deposits it between the pearl layers, and then uses an organic phase containing crown ether (18-crown-6) to dissolve the potassium chlorate into the organic phase through complexation, so that the chlorate ion produces oxidation, and the pigment is oxidized. The present application can keep the bleaching oxidation degree of the pearl surface layer and the pearl deep layer from being greatly different, avoids the problem that the pearl layer surface is excessively oxidized and the pearl deep layer has insufficient oxidation capacity during the bleaching process, and has the advantages of simple process, simple operation, and good bleaching oxidation effect.

A supported composite oxide catalyst, its preparation method, and its application are disclosed, specifically relating to the field of heterogeneous catalysis. This invention provides a supported composite oxide catalyst for the selective oxidation of toluene in the gas phase and its preparation method. This is achieved by using MoVTeNbO... x TeO supported on composite oxide surface y To form a new TeO y / MoVTeNbO x The composite oxide significantly inhibits the over-oxidation of toluene, thereby greatly improving the selectivity of benzaldehyde, and the catalyst exhibits good stability. The catalyst preparation process is simple, reproducible, and shows promising application prospects.

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℃.

The application provides an iron-based oxide catalyst, a preparation method thereof and application of the iron-based oxide catalyst in selective catalytic n-butane-CO2 coupling conversion for preparing butadiene, and mainly solves the problem of low butadiene selectivity in the current n-butane oxidative dehydrogenation system. The pyrolysis method of the organic acid assisted metal salt solution can obtain the iron-based oxide catalyst with uniform particle size, and the iron-based oxide catalyst exhibits excellent butadiene selectivity in the catalytic n-butane-CO2 coupling conversion reaction. Under the conditions of 500-650 DEG C and 0.1 MPa, the n-butane conversion rate is greater than 10%, and the butadiene selectivity is greater than 50%. The CO2 is used as an oxidant, excessive oxidation and the generation of reaction hot spots can be avoided, and the process is safer and more reliable. The pyrolysis method reported in the application has the characteristics of simple operation, cheap and easily available raw materials and good repeatability, and can be used for industrialized application of n-butane oxidative dehydrogenation.

This invention discloses a chemical mechanical polishing (CMP) method for efficient planarization of ruthenium surfaces, comprising: preparing a CMP slurry, wherein the slurry includes an oxidant, a complexing agent, a corrosion inhibitor, an abrasive, and a pH adjuster, and the solvent is deionized water; ultrasonically cleaning a substrate with a ruthenium layer deposited thereon to obtain a ruthenium substrate to be polished; attaching the ruthenium substrate to be polished to the polishing disc of a polishing machine for CMP polishing. This invention employs an oxidation-complexing system of ammonium persulfate and glycine to gently oxidize the ruthenium surface to form a soluble complex, avoiding excessive corrosion. Benzotriazole is used as a corrosion inhibitor, selectively adsorbed on the ruthenium surface to inhibit corrosion in non-polished areas. Nano-silica abrasives provide mechanical removal, synergistically achieving efficient planarization with chemical action. The low pH environment helps inhibit excessive oxidation of ruthenium, improving surface quality and achieving a better polishing effect for the entire ruthenium layer.

The invention relates to the technical field of chemical production, in particular to a preparation method of 1, 2-octylene glycol, the preparation method comprises the steps of oxidation ring-opening esterification reaction, saponification hydrolysis reaction and post-treatment and refining, and an air flotation synergistic layering device comprises a tank body, a central shaft, a pre-filtering unit, an air flotation unit and a driving mechanism; the central shaft is vertically mounted in the tank body, and the top end and the bottom end of the central shaft both penetrate and extend to the outside of the tank body; the center shaft is rotationally connected with the top of the tank body, and a rotating seat fixedly sleeves the bottom end of the center shaft and is rotationally connected with the bottom of the tank body; the driving mechanism is arranged at the top of the tank and used for driving the center shaft to rotate. By accurately controlling the dripping rate of hydrogen peroxide, the reaction temperature and the effective oxygen molar ratio, side reactions such as violent decomposition and over-oxidation of peroxyformic acid are inhibited, and the selectivity and safety of the reaction are improved; and rectification is carried out under the conditions of high vacuum degree and specific tower kettle temperature, so that high-boiling-point impurities can be efficiently separated out, and a high-purity target product can be obtained.

The invention belongs to the technical field of organic synthesis, and relates to a supported catalyst, a preparation method thereof, and an application of the supported catalyst in a reaction for synthesizing methyl glyoxylate from methyl glycolate, the supported catalyst comprises a carrier, and an active metal component and an auxiliary agent component which are supported on the carrier; wherein the active metal component is vanadium; the auxiliary agent component is selected from at least one of silver, molybdenum, yttrium, bismuth, tungsten, manganese, niobium, zinc, zirconium, cerium, cobalt, magnesium, calcium, barium, lanthanum, boron, gallium, germanium or indium. Compared with the prior art, the active metal and the auxiliary agent of the prepared catalyst are concentrated on one layer of the surface of the carrier and are distributed in an eggshell shape, methyl glycolate completes adsorption, reaction and desorption on the surface of the catalyst, a large amount of excessive oxidation products CO and CO2 are prevented from being generated, and the yield of methyl glyoxylate is increased.