16 results about "Catalyst selectivity" patented technology

The preparation of high-value-added aromatic carboxylic acids via CO2 carboxylation coupling through activation of the benzyl C-H bond in alcohols / amines is a green and sustainable pathway to achieve CO2 resource utilization and contribute to carbon neutrality. However, this field currently faces challenges such as poor catalyst selectivity, low CO2 activation efficiency, and a narrow substrate applicability range, making it difficult to meet practical application needs. To address this issue, this patent discovers that in a heterogeneous electrocatalytic system, cuprous selenide (V2), rich in selenium vacancies, can be used... Se -Cu 2‑x Using Se as the core catalyst, it can not only efficiently promote the synergistic activation of benzyl C-H bonds and CO2 carboxylation, significantly improving the overall catalytic activity of the reaction, but also achieve precise chemoselective carboxylation control for different types of substrates. Specifically, this V Se -Cu 2‑x Se electrocatalysts can efficiently and selectively activate the benzyl C-H bond in alcohols and subsequently induce CO2 carboxylation, exhibiting excellent chemoselectivity in the conversion of benzyl alcohol to mandelic acid and its derivatives. Simultaneously, they also demonstrate excellent catalytic performance for amines, selectively catalyzing the carboxylation of amine substrates such as benzylamine with CO2 to directionally generate phenylglycine and aromatic amine-derived carboxylates. Crucially, in addition to typical benzyl alcohol and benzylamine, the substrate applicability of this catalytic system can be extended to various alcohols and amine derivatives, realizing the carboxylation transformation from simple model substrates to diverse functional molecules, providing a new approach for the large-scale preparation of high-value-added aromatic carboxylates.

The application provides a synthesis method and application of a catalyst for preparing formaldehyde by oxidizing methanol, and belongs to the field of catalyst preparation. The iron-molybdenum catalyst containing an additive is synthesized in a micro-channel reactor, the catalyst has high utilization rate of metal elements, light density, uniform granularity, high catalytic stability, high forming strength and long service life. The catalyst is filled in a fixed bed and used for preparing formaldehyde by oxidizing methanol, so that the polymerization of the reaction is reduced, the selectivity of the catalyst is improved, the loss of active components is reduced, and the service life of the catalyst is prolonged. The synthesis process of the catalyst is simple, the catalyst has small and uniform particle size, no flaky impurity crystals, high utilization rate of metal elements, and plays a positive role in treating wastewater generated in the later catalyst production.

The application discloses a kind of squalene continuous flow catalytic hydrogenation squalane application alumina ball load palladium catalyst and its preparation method, the catalyst with gamma-alumina ball as carrier, modification impregnation method load palladium active component, with auxiliary control interface effect, form high dispersion Pd / Al2O3 Catalytic system, palladium loading is 0.01wt%-5wt%.The catalyst is filled in fixed bed reactor, and is applied to squalene continuous flow hydrogenation preparation squalane reaction, using continuous flow hydrogenation process, under mild conditions, squalene can be realized efficient conversion, conversion rate is ≥99%, squalane selectivity is ≥99%.The present application solves the problems of low selectivity, low utilization rate of noble metal and poor stability of existing squalene hydrogenation catalyst, and the problems of low efficiency and difficult industrial continuous production of traditional batch hydrogenation process.The process conditions are mild, environmentally friendly and suitable for industrial application.Compared with traditional Pd / C catalyst, the catalyst has higher activity and stability.

Acrolein is produced by selectively oxidizing iso-propanol over a first mixed metal oxide catalyst in the presence of oxygen in the vapor phase. The first mixed metal oxide catalyst comprises oxides of molybdenum and bismuth. Acrylic acid is produced by selectively oxidizing the acrolein over a second mixed metal oxide catalyst in the presence of oxygen in the vapor phase. The second mixed metal oxide catalyst has a different composition from the first mixed metal oxide catalyst.

This invention discloses a catalyst for the synthesis of chlorobenzene and its application, belonging to the field of catalyst technology. The catalyst is a CeO2@volcanic rock composite material supported on FeCl3 / ZnCl2. This invention uses ferric chloride and zinc chloride, two Lewis acids, as the main catalytically active components, and the CeO2@volcanic rock composite material as the support, loading the catalytically active components via an impregnation method. In the catalyst prepared by this invention, the support structure is optimized through the CeO2 and volcanic rock composite material, allowing ferric chloride and zinc chloride to be highly dispersed and anchored on the support, thus improving catalytic efficiency. The co-loading of ferric chloride and zinc chloride adjusts the acid strength of the Lewis acid, meeting the requirements for activating chlorine gas to generate chlorobenzene, while avoiding secondary substitution, significantly improving catalyst selectivity.

The application discloses a method for continuously synthesizing alpha-acetyl-gamma-butyrolactone, which comprises the following steps: vaporizing 1,4-butanediol and then feeding the vaporized 1,4-butanediol into a first fixed-bed reactor filled with a nano copper oxide catalyst doped with Mn, Al, Yb, Sr and Cr to perform a reaction, so as to obtain gamma-butyrolactone gas; continuously feeding the gamma-butyrolactone gas, vaporized acetic anhydride and nitrogen into a second fixed-bed reactor filled with a silver-modified graphene / SiO2 composite catalyst under the protection of nitrogen to perform a reaction, and then performing rectification on a product obtained through multi-stage condensation, so as to obtain a target product. The method provided by the application has stable reaction conditions, high selectivity and specificity of a catalyst and high yield, and can realize continuous production of the product.

This invention belongs to the field of wax oil hydrocracking reaction. It is a process and method for modifying the product distribution of a wax oil hydrocracking unit by utilizing diesel products from residue hydrocracking. The feedstock in the first stage is pressurized by a first-stage feed pump and mixed with hydrogen. After being heated to the reaction temperature, it enters a first-stage refining reactor and a first-stage cracking reactor for reaction. The first-stage reaction products undergo gas-liquid separation through a fractionation system. The supervaporized oil and unconverted oil remaining after fractionation are used as feedstock for the second-stage reactor. This feedstock is mixed with high-NOx diesel as the second-stage feedstock, pressurized by a second-stage feed pump, mixed with hydrogen, heated to the reaction temperature, and then enters the second-stage cracking reactor for reaction. The second-stage reaction products undergo gas-liquid separation through a fractionation system. This invention involves blending a small amount of high-NOx diesel produced from a residue hydrocracking unit into the second-stage feedstock of a two-stage full-cycle wax oil hydrocracking unit. This passivates the activity of the second-stage cracking catalyst, improves catalyst selectivity, reduces LPG yield, and increases the C5 content of the product. + Liquid yield.

This invention relates to a method for the catalytic preparation of 1,5-pentamethylene diisocyanate trimer, belonging to the field of organic synthesis and polymer materials technology. Addressing the problems of poor catalyst selectivity and the tendency to generate pentamers and higher polymers in existing PDI trimer synthesis processes, leading to increased product viscosity and decreased NCO content, this invention proposes using potassium isooctanoate catalyst under nitrogen protection. The purified PDI monomer is heated to 90°C, and 0.8‰ (based on the mass of PDI monomer) of catalyst is rapidly added dropwise. The reaction is controlled until the NCO conversion reaches 30%, then a terminator is added to terminate the reaction, followed by molecular distillation to remove residual monomers. Gel permeation chromatography (GPC) analysis shows that the obtained product contains 29.46% trimer, and the contents of pentamers, heptamers, and high polymers (n≥9) are 5.74%, 2.12%, and 5.90%, respectively. This invention achieves highly selective synthesis of PDI trimer, producing a product with low viscosity and high NCO content, which can be used as a curing agent for high-performance polyurethane coatings and has promising industrial application prospects.

The present application relates to the technical field of catalyst preparation, in particular to a preparation and application of a core-shell catalyst with a chemically bonded hydrophobic layer. The present application overcomes the problems of low selectivity and low conversion rate of the existing propylene oxide production catalyst. The modified carrier is obtained by extruding silica gel powder and silica sol, the molybdenum active center is solidified by impregnation and multi-stage step calcination, then gaseous titanium tetrachloride is introduced in an inert atmosphere to form an in-situ reaction, a chemically bonded titanium protective shell is formed, finally gaseous hexamethyldisilazane is introduced for surface chemical grafting to build a persistent super-hydrophobic outer layer. The present application breaks the limitations of traditional liquid phase physical coating, adopts a full gas phase sequence from inside to outside, avoids the damage of capillary force to the pore, and obtains a catalyst with high mechanical strength, good reaction selectivity and prolonged service life, which has industrial application prospect.

The present application relates to the technical field of catalyst, in particular to a hydrogenation catalyst, a preparation method thereof and a method for preparing low-carbon alcohol by carbon dioxide hydrogenation. The catalyst comprises a carrier and an active component, the carrier comprises a ternary composite carrier containing SiO2, MnO2 and ZrO2, and the active component comprises K element and Cu element. The hydrogenation catalyst of the present application comprises the ternary composite carrier containing SiO2, MnO2 and ZrO2 and the active component containing K element and Cu element, the carrier can well disperse the active component K element and Cu element in the catalyst, effectively limits the growth and aggregation of copper grains at high temperature, prolongs the service life of the catalyst, improves the selectivity and catalytic efficiency of the catalyst.

This invention discloses a bio-based carbon nanotube catalyst and its application in the synthesis of LC-grade DETDA. The catalyst uses biomass-derived carbon nanotubes as a support, loading two inorganic modified compounds: neodymium-doped mesoporous zirconium tungstate and boron-nitrogen co-doped hexagonal cobalt molybdate nanosheets. The key to its preparation lies in the synthesis of neodymium-doped mesoporous zirconium tungstate with uniform doping and mesoporous structure via hydrothermal and solid-state grinding methods, respectively, and the synthesis of boron-nitrogen co-doped hexagonal cobalt molybdate nanosheets with regular nanosheet morphology and boron-nitrogen co-doping effect via a two-step hydrothermal method, which are then finally combined with activated bio-based carbon nanotubes. This catalyst exhibits high activity, high selectivity, and excellent cycling stability in the selective hydrogenation and cyclization of diethylnitrotoluene to prepare high-purity diethyltoluene diamine, effectively solving the problems of insufficient selectivity, easy deactivation, and dependence on noble metals in traditional catalysts, and possesses significant industrial application prospects.

This invention discloses a process for synthesizing tetrachloropropene from carbon tetrachloride, comprising the following steps: S1) Preparation of 1,1,1,3-tetrachloropropane via telomerization reaction. Carbon tetrachloride is used as a raw material, and ethylene is subjected to telomerization reaction under the catalysis of a metal-carbon composite catalyst. The metal-carbon composite catalyst is prepared by a four-step process of mixing, carbonization, displacement, and loading, and directionally catalyzes the generation of crude 1,1,1,3-tetrachloropropane. This application significantly improves the catalytic activity and product selectivity of the telomerization reaction between carbon tetrachloride and ethylene by employing a self-prepared metal-carbon composite catalyst. It can directionally generate the 1,1,1,3-tetrachloropropane intermediate, effectively suppressing side reactions and improving the yield of the target product and the conversion rate of raw materials. This catalyst, prepared by a four-step process of mixing, carbonization, displacement, and loading, has a stable structure, long service life, and can be recycled multiple times, significantly reducing catalyst consumption and production costs, and solving the problems of poor selectivity and insufficient stability of traditional catalysts.

A preparation method of a dehydrogenation catalyst and a method for preparing gamma-butyrolactone by dehydrogenating 1,4-butanediol, the catalyst is prepared by co-precipitation method to prepare a slurry of copper and zinc composite oxide, co-precipitation method is used to prepare a slurry of copper, chromium and zirconium composite oxide, the two slurries are mixed, reacted, dried and calcined to obtain a mixture, and then the mixture is impregnated in a salt solution of M element; M element is selected from at least one of Li, Na, K, Ca, Mg and Ba. According to the present application, the active metal copper is distributed on different carriers by step-by-step precipitation, the dispersion degree is high, the H2 adsorption and desorption, dehydrogenation reaction, anchoring of active copper particles and other multifunctional coupling are realized, high catalytic activity is exhibited, the catalyst can be activated at a lower temperature, energy consumption is saved, and because the side reaction of BDO dehydration to form tetrahydrofuran is an endothermic reaction, therefore, reducing the reaction temperature is beneficial to inhibiting the formation of tetrahydrofuran; the addition of M element can weaken the dehydration active center and further inhibit the formation of tetrahydrofuran, so as to improve the selectivity of the catalyst.

The application discloses a synthesis method of O-3-chloro-2-propenyl hydroxylamine, which comprises the following steps: directly reacting compound B with water under the action of a catalyst to obtain O-3-chloro-2-propenyl hydroxylamine; and the catalyst is Amberlyst-15 resin. According to the application, O-3-chloro-2-propenyl hydroxylamine can be prepared from compound B in one step by selecting a special catalyst, the operation is simple, the selectivity of the catalyst is high, the side reaction is less, the reaction process is easy to control, and the participation of hydrochloric acid and liquid alkali is not needed in the reaction process, so that waste salt and waste water such as sodium chloride and sodium acetate are not generated, the environmental protection pressure is reduced, and the application is a green route with wide prospects.

This invention discloses a low-sulfur, low-nitrogen green carbon raiser and its production method, relating to the field of metallurgical materials technology. The carbon raiser is prepared from lignocellulosic waste as raw material through multi-stage gradient pyrolysis, directional catalytic cracking, and inert atmosphere cooling. The method includes: raw material pretreatment; primary low-temperature pyrolysis; secondary medium-temperature pyrolysis; tertiary high-temperature graphitization; directional catalytic cracking; closed-loop tail gas purification and resource recovery; and inert atmosphere cooling and sieving. This invention is low in sulfur and nitrogen, possesses a highly ordered graphite microcrystalline structure, and incorporates [a process involving the introduction of...] CeO2–ZrO2 / γ‑Al2O3 The catalyst selectively cracks C–N / C–S bonds, and is equipped with a closed-loop exhaust gas purification system to achieve near-zero emissions. It has the advantages of high carbon yield, ultra-clean impurity control and green manufacturing throughout the entire life cycle, solving the problems of high sulfur and nitrogen impurities and high carbon emissions in the preparation process of traditional carbon additives.

The application belongs to the technical field of organic synthesis, and particularly relates to selective oxidation of thioether to prepare sulfoxide and sulfone by using zirconium hydroxide as a catalyst. The application uses thioether as raw material, zirconium hydroxide as catalyst, and hydrogen peroxide as oxidant. Sulfoxide can be catalytically oxidized and synthesized in a short reaction time, and sulfone can be obtained by prolonging the reaction time. The selectivity can be regulated only by the reaction time without any additives. The zirconium hydroxide catalyst can be directly purchased or prepared by using a simple precipitation method with zirconium salt as a precursor, and is low in price. Hydrogen peroxide is used as an oxidant, and is green, stable, low in cost, high in atomic efficiency (47% active oxygen), and has water as the only by-product. In addition, the reaction process is simple in operation, low in cost, and high in yield, and has great industrial application prospect.