409 results about "Hexamethylenetetramine" patented technology

The invention relates to the field of materials, in particular to a silicon dioxide aerogel composite thermal insulation material and a preparation method thereof. The silicon dioxide aerogel composite thermal insulation material is prepared by taking silicon dioxide aerogel, phenolic resin, a nano zirconium oxide graft and a locust bean gum graft as main raw materials and taking n-pentane, UV-327, hexamethylenetetramine and an antioxidant 1010 as auxiliary materials. The nano zirconium oxide graft and the locust bean gum graft are added into the silicon dioxide aerogel material, so that the prepared silicon dioxide aerogel composite material has excellent heat-insulating property, flame-retardant property and toughening effect, and the comprehensive requirements of the use scene of the silicon dioxide aerogel composite material on toughness and flame retardance are met; and the application market is expanded.

The invention relates to the technical field of polyester, in particular to a flame-retardant and antibacterial dual-function fiber and a preparation method thereof. The flame-retardant antibacterial fiber overcomes the defects that existing fibers are poor in flame retardance and antibacterial property. According to the invention, PET resin, a composite modified auxiliary agent master batch and a composite flexibilizer are used as raw materials, and the bifunctional fiber is prepared through melting and spinning; wherein the composite modified additive master batch is prepared from the following raw materials: PET (Polyethylene Terephthalate) resin, aluminum diethylphosphinate, modified halloysite nanotubes, modified zinc oxide nanowires and zinc borate; the modified halloysite nanotube is prepared from the following raw materials: a halloysite nanotube, KH560 and phosphoric acid; the modified zinc oxide nanowire is prepared from the following raw materials: zinc nitrate hexahydrate, hexamethylenetetramine and sodium hypophosphite. By controlling the dosage of each component and processing technological parameters, the finally prepared difunctional fiber has good flame retardance and good antibacterial property, and is suitable for manufacturing curtains.

The invention discloses a nitrogen-doped zinc ion battery manganese-based positive electrode material and a preparation method and application thereof, and the preparation method comprises the following steps: mixing a strong oxidant and a manganese salt, putting the mixture into a beaker, adding deionized water, and uniformly stirring to form a mixed solution; transferring the mixed solution into a high-pressure reaction kettle with a polytetrafluoroethylene lining, and heating the high-pressure reaction kettle in a drying oven; cooling, precipitating, filtering and washing for multiple times, and then putting into a drying oven for vacuum drying to obtain an original manganese-based positive electrode material; the preparation method comprises the following steps: respectively weighing an original manganese-based positive electrode material and hexamethylenetetramine, flatly laying the original manganese-based positive electrode material at the bottom of a lining of a reaction kettle, and putting the hexamethylenetetramine into a beaker; and putting the beaker into a reaction kettle, moving the beaker and the reaction kettle into a drying oven, and heating to obtain the surface nitrogen-doped manganese-based positive electrode material.

The invention relates to the technical field of refractory materials, in particular to a magnesium-calcium-zirconium-carbon brick production method which comprises the following components in parts by weight: 60-80 parts of sintered magnesium-calcium-zirconium sand particles, 10-30 parts of fused magnesia particles, 2-4 parts of zirconium oxide, 0.5-3 parts of silicon carbide fine powder, 2-6 parts of nano yttrium oxide high-dispersion particles, 1-2 parts of C9 petroleum resin powder, 2-7 parts of graphite, 4-6 parts of binding agent and 0.3-0.5 part of urotropin. The rare earth material nano yttrium oxide high-dispersion particles are introduced, the magnesium-calcium-zirconium-carbon brick has the advantages of high temperature resistance, good hydration resistance, good thermal shock resistance, good oxidation resistance and good erosion resistance, the magnesium-calcium-zirconium-carbon brick is dried by an electric drying kiln as an unburned brick, a tunnel kiln firing process is omitted, the labor cost and energy consumption are reduced, and the production cost is reduced. And the emission of greenhouse gas and toxic and harmful gas generated by fuel combustion is avoided, and the biomass fuel is an environment-friendly product.

The invention discloses a three-dimensional multi-interface heterostructure lithium-sulfur battery interlayer, a preparation method thereof and a lithium-sulfur battery, and the preparation method comprises the following steps: placing acidified carbon cloth in a mixed solution of cobalt nitrate, nickel nitrate and hexamethylenetetramine for primary hydrothermal reaction to prepare NiCo2O4 (at) CC; the NiCo2O4 (at) CC is placed in a mixed solution of nickel chloride and sodium molybdate, a secondary hydrothermal reaction is carried out, and NiMoO4 (at) NiCo2O4 (at) CC is obtained; according to the preparation method, NiMoO4-coated NiCo2O4-coated CC is subjected to thermal reduction annealing in a mixed atmosphere of hydrogen and argon, the three-dimensional multi-interface heterostructure lithium-sulfur battery interlayer is prepared, active sites of the three-dimensional heterostructure are increased, the oxidation-reduction reaction efficiency under high sulfur loading capacity is improved, the nano-particle anchored amorphous nanosheets form the multi-interface heterostructure, and the performance of the lithium-sulfur battery is improved. Good chemical adsorptivity and catalytic conversion on polysulfide in the battery are realized, and the cycle life of the battery is prolonged.

The invention relates to a preparation method of a carbon fiber reinforced carbon aerogel heat insulation composite material, which comprises the following steps: firstly, pre-oxidizing a commercial polyacrylonitrile (PAN) needled felt reinforcement at 195-255 DEG C to obtain pre-oxidized felt reinforcements with different pre-oxidation degrees; uniformly mixing phenolic resin serving as an organic sol raw material, hexamethylenetetramine serving as a cross-linking curing agent and normal propyl alcohol serving as a solvent according to a proper proportion to form organic sol; secondly, the pre-oxidized felt blank body is placed in a stainless steel mold, organic sol is poured into the stainless steel mold, the pre-oxidized felt is completely immersed in the sol, and the pre-oxidized felt reinforcement is fully soaked in the organic sol under the vacuum negative pressure condition; sealing the stainless steel mold dipped with the pre-oxidized felt, and curing and aging for 40-80 hours at 80 DEG C to obtain pre-oxidized felt reinforced organic wet gel; placing the wet gel at room temperature for 24 hours, and drying the wet gel in an air dry oven at 60 DEG C for 72 hours to obtain pre-oxidized felt reinforced organic aerogel; and finally, carbonizing the pre-oxidized felt reinforced organic aerogel at 850-1100 DEG C for 3 hours by using a vacuum carbonization furnace at a heating rate of 3-5 DEG C / min to obtain the carbon fiber reinforced carbon aerogel composite material.

The invention relates to the technical field of capacitor electrode materials, in particular to a biomass derived porous carbon and layered double hydroxide (LDH) composite material and a preparation method and application thereof. The invention provides a preparation method of a biomass-derived porous carbon and LDH composite material, which is characterized by comprising the following steps: mixing biomass-derived porous carbon, nickel salt, cobalt salt, ethylene glycol, hexamethylenetetramine and water, and carrying out hydrothermal reaction to obtain the biomass-derived porous carbon and LDH composite material, the pore structure of the biomass derived porous carbon comprises micropores, mesopores and macropores. The biomass derived porous carbon and LDH composite material has good specific capacitance, energy density and cycling stability, and can be used as a high-performance supercapacitor electrode material.

The invention relates to the technical field of wastewater treatment, and provides a treatment method of glycine production wastewater. The treatment method of glycine production wastewater comprises the following steps: (1) rectifying glycine wastewater to recover methanol, adding dilute sulphuric acid to adjust the pH value to 2.5-3.0, stirring, and standing; (2) transferring the supernate into another container, adding a ZIF-8 modified material, stirring, standing, filtering, collecting filter residues and filtrate, washing the filter residues with diethyl ether, and recovering urotropine; and (3) evaporating and concentrating the filtrate under the vacuum condition of-0.08 MPa and the temperature of 50-60 DEG C, and separating out high-purity ammonium chloride crystals. According to the treatment method for the glycine production wastewater, the problem that an existing treatment method is poor in removal effect on urotropin in the glycine production wastewater is solved; and the treated glycine production wastewater reaches the discharge standard.

The embodiment of the invention relates to a composite material as well as a preparation method and application thereof, and the preparation method comprises the following steps: dissolving phenolic resin in absolute ethyl alcohol, adding hexamethylenetetramine, and uniformly mixing to obtain a first solution; dissolving a metal salt used for synthesizing a metal organic framework compound MOFs in absolute ethyl alcohol, and then adding a ligand to obtain a second solution; adding the first solution into the second solution, and carrying out heat treatment, so that the phenolic resin and hexamethylenetetramine are subjected to a sol-gel reaction and the metal salt and the ligand are subjected to a complexation reaction, and MOFs / phenolic resin wet gel is obtained; the MOFs / phenolic resin wet gel is subjected to drying treatment, and MOFs / phenolic resin aerogel is obtained; under the inert atmosphere, the MOFs / phenolic resin aerogel is placed in a rotary furnace to be subjected to carbonization treatment, and a carbonized compound is obtained; and activating the carbonized compound in the atmosphere of carbon dioxide and water vapor, and cooling in an inert atmosphere to obtain the composite material.

The invention discloses a method for preparing battery-grade iron phosphate by utilizing phosphated residues. The method comprises the following steps: pre-treating the phosphated residues; alkaline leaching is conducted on the phosphated residues, wherein the phosphated residues are placed in a sodium hydroxide solution with the mass fraction being 30%; decoloring is performed; acid treatment: adding hydrochloric acid into the filtrate to adjust the pH value, adding a solution composed of urotropin, thiourea, tetraethylammonium oxalate, hydrogen peroxide and polydodecyl acrylamide acrylic acid, and stirring; extracting: adding an extracting agent and an organic solution, and extracting under a stirring condition; precipitating: heating the raffinate, adding hexadecyl trimethyl ammonium chloride, and stirring; then adding a ferric nitrate solution to carry out precipitation reaction; the method for preparing the battery material ferric phosphate product by taking phosphated residue solid wastes generated in the steel metal product process as raw materials through the steps of pretreatment, alkaline leaching, decoloration, acid treatment, extraction, precipitation reaction and the like has the advantages of simple process, high product quality, low production cost, high recovery efficiency of phosphorus resources in the waste residues and the like.

The invention discloses a modified phenolic resin and a preparation method thereof, and belongs to the technical field of phenolic resins, the modified phenolic resin comprises the following raw materials by mass: 100 parts of phenol, 140-145 parts of a formaldehyde aqueous solution, 25-30 parts of gradient topology phosphonate, 15-17 parts of hyperbranched siloxane, 12-14 parts of a dynamic borate cross-linking agent, and 3-4 parts of hexamethylenetetramine. Through the synergistic effect of the gradient topology phosphonate, the hyperbranched siloxane and the dynamic boric acid ester cross-linking agent, the flame retardance, the thermal stability, the mechanical property and the dynamic function of the phenolic resin are comprehensively improved, and the environmental protection property of the phenolic resin is remarkably superior to that of a traditional technology. The experimental data fully verifies the inseparability and synergistic interaction among innovation points, and the technical combination and effect are non-obvious and accord with the creativity requirement of the patent. In addition, the application potential of the resin in the fields of aerospace, electronic packaging and the like further highlights the industrial value of the resin.

The invention discloses a self-lubricating aluminum coating and a preparation method thereof.The preparation method comprises the steps that molybdenum disulfide is pretreated through a silane coupling agent, tetraethoxysilane mixed liquor is added, the pH is adjusted to be 9-10, a water bath reaction is conducted, and molybdenum disulfide-silicon dioxide microcapsules are obtained after high-temperature strengthening treatment; respectively adding a zinc nitrate solution and a hexamethylenetetramine solution, adjusting the pH value to 10-11, carrying out a high-temperature and high-pressure hydrothermal reaction to obtain zinc oxide nanorods, and carrying out ball milling treatment on the zinc oxide nanorods, microcapsules, stearic acid and zirconium oxide balls under the protection of argon to obtain doped microcapsules; after raw materials are pretreated, the raw materials and a dispersing agent solution are added into a mixer respectively, spraying powder, a pretreated base body and the spraying powder are obtained after mixing treatment, spraying treatment is conducted on the surface of the base body through a plasma spraying method, and the self-lubricating aluminum coating is obtained after vacuum annealing treatment. Therefore, the obtained self-lubricating aluminum coating is low in friction coefficient, high in performance and excellent in self-lubricating property.

The invention discloses a preparation method of a carbon fiber cloth coated SixFe1-xO2 nanorod material, which comprises the following steps: dissolving a silicon source and an iron source in a mixed solution of ethanol and ethylene glycol, adding hexamethylenetetramine and urea step by step, stirring and dissolving to obtain a mixed solution, then putting the mixed solution and carbon fiber cloth into a high-pressure reaction kettle together, and stirring for 30-60 minutes to obtain the carbon fiber cloth coated SixFe1-xO2 nanorod material. The preparation method comprises the following steps: adding a carbon fiber cloth coated SixFe1-x (OH) 4 nanorod material into a reaction kettle, reacting at a certain temperature in a constant-temperature drying box, then naturally cooling to room temperature, washing and drying to obtain the carbon fiber cloth coated SixFe1-x (OH) 4 nanorod material, putting the carbon fiber cloth coated SixFe1-x (OH) 4 nanorod material into a muffle furnace, and annealing in an air environment to obtain the carbon fiber cloth coated SixFe1 The synthesis process is simple, the cost is low, the requirement for equipment is low, the controllable degree is high, and the obtained product is uniform and novel in morphology, has high charging and discharging capacity and long cycle life as a flexible negative electrode material, and has wide application in the fields of flexible batteries, photoelectric devices and the like.

The invention discloses a resourceful treatment method for mother liquor in a glycine production process. The method comprises the following steps: introducing hydrogen chloride gas into mother liquor in a glycine production process to obtain hydrolysate; centrifugally separating the hydrolysate to obtain an ammonium chloride product, and treating the primary centrifugal filtrate in the next process; adding urea into the centrifugal filtrate for reaction, and after the reaction is completed, carrying out centrifugal separation to obtain a solid product urea-formaldehyde resin and a secondary centrifugal filtrate; the secondary centrifugal filtrate is heated, methyl alcohol in the filtrate is removed, methyl chloride is recycled, then heating continues, water in the filtrate is removed, evaporation condensate water is obtained, methyl chloride can be collected to serve as a by-product to be sold, the evaporation condensate water is reused for glycine production, and evaporation residual liquid serves as organic matter fertilizer to be treated. Under the condition of low energy consumption, impurities such as urotropin, ammonium chloride and methanol ammonia in the glycine mother liquor are separated, and resources such as urotropin, ammonium chloride and methanol in the mother liquor are recycled.

The invention discloses a catalyst carrier and a preparation method and application thereof, and belongs to the technical field of catalyst carriers, the preparation method comprises the following steps: mixing alumina sol with a composite template agent, tin chloride and silica sol to obtain slurry; preparing carrier wet balls from the slurry, drying and roasting to obtain the catalyst carrier; the composite template agent comprises a surfactant and organic amine, the surfactant is a zwitterionic surfactant and a nonionic surfactant, and the organic amine is hexamethylenetetramine; the mass ratio of the surfactant to the organic amine is 1: (10-20); the mass ratio of the zwitterionic surfactant to the nonionic surfactant is 1: (1-2). According to the invention, the crushing strength reaches 71N / particle to 80N / particle, the specific surface area reaches 138 m < 2 > / g to 165 m < 2 > / g, the performance of the alumina catalytic carrier is greatly improved, and technical support is provided for long-term efficient and stable operation of a catalyst.

The invention discloses a reagent combination, an analyzer and a detection method for detecting beryllium element content in a water sample. The reagent combination is composed of a color developing agent, a masking agent, a buffer solution and a catalytic solution. The color developing agent comprises chrome cyanine R; the masking agent comprises EDTA (Ethylene Diamine Tetraacetic Acid), ascorbic acid, tartaric acid and ethylene glycol amine; the buffer solution comprises ammonium acetate and hydrochloric acid; the catalytic liquid comprises hexadecylpyridinium chloride. Compared with a standard method, the adopted reagents have the advantages that the reaction steps are simplified, the stability of the reagents is better, the shelf life is longer, the reagents such as ammonia water and hexamethylenetetramine used in the standard method not only have pungent smell and larger environmental pollution, but also are easy to volatilize and deteriorate, and are not beneficial to long-term storage, so that the long-term measurement result is deviated, and the accuracy of the detection result is improved. Reagents used in the method do not have the defects, and can be stored for a long time at normal temperature, so that the method can be suitable for unattended automatic instruments and automatic water quality monitoring stations.

The invention discloses a preparation method of a low-expansion silicon-carbon negative electrode material, which comprises the following steps: (S1) uniformly mixing an aldehyde monomer, a phenol monomer, hexamethylenetetramine and aluminum oxide, heating and polymerizing to obtain thermosetting phenolic resin, and calcining at high temperature to obtain high-strength carbon; (S2) performing physical activation on the high-strength carbon to obtain high-strength porous carbon; and (S3) by taking the high-strength porous carbon as a substrate, sequentially carrying out silicon deposition and carbon coating to prepare the low-expansion silicon-carbon negative electrode material. The porous carbon prepared by a specific method has high strength, high conductivity and an excellent pore structure, and the silicon-carbon negative electrode material prepared by taking the porous carbon as the substrate has high cycle stability and low expansion rate.

The invention provides a phosphorus-doped nitrogen-rich porous carbon nanosheet for regulating nitrogen activity as well as a preparation method and application of the phosphorus-doped nitrogen-rich porous carbon nanosheet, and belongs to the technical field of preparation of negative electrode materials. The preparation method of the phosphorus-doped nitrogen-rich porous carbon nanosheet for regulating and controlling the nitrogen activity comprises the following steps: adding a metal source solution into an amine compound solution, stirring to obtain a precipitate, washing and drying to obtain a nanosheet precursor, then heating in an inert gas atmosphere, preserving heat to obtain a two-dimensional N / C nanosheet, and finally phosphating the two-dimensional N / C nanosheet, the amine compound comprises hexamethylenetetramine. The phosphorus-doped nitrogen-rich porous carbon nanosheet for regulating and controlling the nitrogen activity has relatively large interlayer spacing and rich pore defects and edge sites, can adsorb more Na < + >, can effectively reduce the diffusion distance of Na < + >, and has excellent conductivity as a negative electrode material.

The invention provides a bifunctional self-supporting electrode composite material and a preparation method and application thereof.The preparation method comprises the steps that NiMoOx nanowires growing on foamed nickel are added into a mixed solution containing a nickel source, a cobalt source, an iron source and hexamethylenetetramine, hydrothermal reaction is conducted, and a precursor is obtained; and then pyrolyzing in a hydrogen and argon mixed atmosphere to obtain the difunctional self-supporting electrode composite material. Compared with the prior art, hexamethylenetetramine is used for in-situ synthesis of NiCoFe-MoNi4 / MoO2 / NF on the surface of the NiMoOx nanowire at a low temperature, and the NiCoFe-MoNi4 / MoO2 / NF is used as an effective difunctional electrocatalyst for complete water splitting. According to the invention, a strong synergistic effect is generated between the ternary NiCoFe compound and MoNi4 / MoO2, so that the intrinsic activity of the catalyst is improved. The catalyst simultaneously serves as a cathode and an anode to participate in catalytic reaction, and the performance of the catalyst exceeds the catalytic performance of commercially available noble metal electrodes.

The invention discloses a method for preparing a porous carbon material by using petroleum coke and biomass as raw materials, which comprises the following steps: respectively crushing and drying a biomass raw material and a petroleum coke raw material, adding a dry biomass fine powder material and a dry petroleum coke fine powder material into urotropine, melamine, alcohol ether carboxylate and water according to a ratio, adding the materials into a reactor, stirring, mixing and reacting; the cured product is fed into a tubular furnace to be subjected to heat treatment in the nitrogen atmosphere, and a carbonized product is obtained; and activating the carbonized product in a carbon dioxide atmosphere to obtain the porous carbon material with the specific surface area of 1510-2090 m < 2 > / g, the total pore volume of 0.72-0.99 cm < 3 > / g and the average pore size of 1.71-2.29 nm. The raw material proportion, the mixing aid dosage and the carbonization activation condition can be adjusted according to different biomass types, the pore distribution of the product can be flexibly adjusted, and the method can be applied to different scenes. The method is low in cost, environment-friendly, controllable in product stability and suitable for large-scale production and application.

The invention discloses a high-strength flame-retardant phenolic molding compound and a preparation method thereof, and belongs to the technical field of phenolic molding compounds. Comprising the following raw materials in parts by weight: 70-90 parts of phenolic resin, 5-8 parts of hexamethylenetetramine, 10-20 parts of pretreated glass fibers, 8-16 parts of a flame retardant and 1-3 parts of a lubricant. Wherein the pretreated glass fiber reinforced molding compound solves the problem of interfacial compatibility between fibers and a resin matrix, reduces stress concentration, and improves the strength of the molding compound; wherein the flame retardant has a phosphorus-boron-nitrogen synergistic flame retardant effect, the flame retardant property of the phenolic molding plastic can be remarkably improved, the problem of insufficient flame retardant property of the traditional phenolic molding plastic is solved, and the flame retardant is halogen-free and environment-friendly; therefore, the phenolic moulding plastic prepared by the invention has both flame retardance and high strength, and has important application value in the technical field of phenolic moulding plastics.

The invention provides a method for detecting the content of glycine and urotropine in glycine wastewater, and belongs to the technical field of analytical chemistry. The method comprises the following steps: firstly, obtaining a standard curve by utilizing a standard solution of glycine and urotropine, and then comparing the consistency of retention time of two main peaks of glycine and urotropine in a standard mixed solution and the retention time of a main peak in a sample to be detected, and substituting into the standard curve to obtain the content of glycine and urotropine in the sample to be detected. According to the method, when a standard mixed solution of glycine and urotropine is prepared, the weight ratio of glycine to urotropine is limited to be 1: 1, mobile phase ultrapure water and chromatographic grade methanol selected during high performance liquid chromatography testing are used as solvents, and during high performance liquid chromatography testing, an isocratic elution mode is adopted for elution, so that the content of glycine and urotropine in the mixed solution is greatly improved. Therefore, the obtained working curve prepared by using the respective chromatographic area and concentration data of glycine and urotropine has good linear correlation, and the test accuracy is further improved.

The invention relates to the technical field of precoated sand, in particular to high-performance precoated sand and a preparation method thereof.The formula comprises silica sand, reclaimed sand, resin, urotropine, calcium stearate and superfine silica powder accounting for 0.1-1% of the total weight of the formula, the SiO2 content of the superfine silica powder is 99% or above, the average particle size is 1-5 microns, and the particle size distribution span (D90-D10) / D50 is smaller than 0.5. The preparation method comprises the following steps: S1, heating the silica sand and the reclaimed sand to 125 + / -10 DEG C; s2, transferring the heated sand into a sand mixer, stirring at a low speed for 4 + / -0.5 min, adding superfine silica powder, and continuously stirring for 50 + / -10 s; s3, resin, urotropine and calcium stearate are sequentially added, and low-speed stirring is conducted for 180 + / -10 s; and S4, screening and cooling the mixed sand material, and bagging the mixed sand material after the mixed sand material reaches the normal temperature. By adding 0.1-1% of superfine silica powder, the high-temperature strength of the precoated sand is improved, sand mold cracking is reduced, the casting quality is improved, and meanwhile by adopting reclaimed sand, the cost is reduced.

The invention discloses a preparation method of a composite material for a fire-fighting blanket and a method thereof, and belongs to the technical field of fire-extinguishing materials. The composite material for the fire-fighting fire blanket is prepared from the following raw materials in parts by weight: 40 to 50 parts of phenolic resin, 20 to 30 parts of acrylic resin, 4 to 8 parts of hexamethylenetetramine, 1 to 3 parts of polyol glycidyl ether, 15 to 20 parts of ammonium polyphosphate, 4 to 10 parts of pentaerythritol, 1 to 2 parts of dispersing agent, 10 to 15 parts of fire extinguishing agent microcapsule, 5 to 10 parts of poly (N-isopropylacrylamide) and 5 to 10 parts of solvent. In addition, the invention further provides a preparation method of the composite material for the fire blanket. The composite material provided by the invention can realize repeated fire extinguishing of the fire blanket.

The present invention relates to a preparation method of beta-methylenepyridine-2-ethanol. The preparation method of beta-methylenepyridine-2-ethanol uses 2-picoline as a first raw material, formaldehyde solution or paraformaldehyde as a second raw material, and urotropine as a catalyst, and reacts according to the following steps: (1) the first raw material, the second raw material, the catalyst and water are mixed and placed in an autoclave, the temperature is raised to 140-160° C., and after reacting for 18-20 hours, a solution containing beta-methylenepyridine-2-ethanol is obtained; (2) the solution containing beta-methylenepyridine-2-ethanol is distilled to obtain a product. The present application uses urotropine as a catalyst, utilizes its unique spatial structure and charge distribution, improves the selectivity of the reaction, and the reaction process is solvent-friendly, the steps are simple, and beta-methylenepyridine-2-ethanol can be obtained by a one-pot method, which is suitable for industrialization.

To provide the underlayer for a disc brake pad, which is positioned between a back plate and a friction material providing excellent brake noise suppression effect. The underlayer composition contains 5-15 weight % of the uncrosslinked fluororubber relative to the entire amount of the underlayer composition, 4-8 weight % of the phenol-based resin as the binder relative to the entire amount of the underlayer composition, and 0.3-2 weight % of the hexamethylenetetramine as the curing agent for the phenol-based resin relative to the entire amount of the underlayer composition.

The invention relates to the technical field of zinc hydrometallurgy, and discloses an analysis method for measuring high cobalt content by an EDTA complexing back titration method, which is based on the following steps: oxidizing Co < 2 + > into Co < 3 + > by using potassium nitrite in an acetic acid medium to form cobalt potassium nitrite precipitate so as to realize separation of cobalt and interfering ions, dissolving the precipitate, complexing with excessive EDTA, and performing back titration by using a zinc standard solution. Xylenol orange is used as an indicator, and determination is completed at room temperature in a hexamethylenetetramine buffer system with the pH value being approximately equal to 5.8. Coexisting ion interference is effectively eliminated through tartaric acid, sodium fluoride, thiourea and other masking agents, the method has the advantages of being easy and convenient to operate, sensitive in end point, high in accuracy and low in cost, and the requirement for conventional analysis of high-cobalt materials can be met.

The invention relates to the technical field of tire rubber, and discloses a cord fabric rubber composition containing composite masterbatch and a preparation method of the cord fabric rubber composition. Composite masterbatch is introduced into the rubber composition, and the rubber composition is prepared by mixing natural rubber, liquid regenerated rubber, cracked carbon black and hexamethylenetetramine. Wherein the glass transition temperature Tg of the liquid regenerated rubber is-60 to-50 DEG C, and the oil content of the liquid regenerated rubber is 4-8wt%; the BET specific surface area of the cracked carbon black is 60-100 m < 2 >. G <-1 >, the ash content is 15-25 wt%, and the ZnS content in the ash content is 5-12 wt%. The added composite master batch can effectively replace part of natural rubber and furnace black, the bonding strength and fatigue resistance of the rubber material are improved and the scorching safety area is expanded on the premise of not influencing the mechanical properties of the rubber composition, and the composite master batch is beneficial to reduction of heavy metal emission and carbon emission and improvement of economic benefits.

The invention provides a nitrogen and sulfur co-doped carbon material adsorbent as well as a preparation method and application thereof, and belongs to the technical field of new materials. According to the simple and efficient synthesis method of the carbon-based adsorbent, hexamethylenetetramine is used for replacing ammonia and formaldehyde to be polymerized with resorcinol to form resin balls, in addition, NH4 < + > released by hydrolysis of hexamethylenetetramine is also a source of nitrogen in a carbon skeleton, and the surface performance of the resin balls can be improved. Meanwhile, thiourea is introduced, nitrogen and sulfur are doped into resin balls at the same time to participate in formation of pore channels, and the pore diameter structure is adjusted. Finally, through activation modification of KOH, the pore structure of the carbon spheres is further adjusted, more micropores beneficial to separation of CO2 / CH4 and CH4 / N2 are generated, and the simple and effective synthesis method provides huge potential for large-scale production of microporous carbon and nitrogen-doped carbon.

The invention discloses a magnesium carbonate crystal prepared based on hexamethylenetetramine and a preparation method thereof, and belongs to the technical field of magnesium carbonate materials. The preparation method comprises the following steps: dissolving urea and magnesium chloride, adding hexamethylenetetramine, oscillating in water bath ultrasonic to fully react, then transferring the reaction system into a hydrothermal reaction kettle to perform hydrothermal reaction, and washing and drying a reactant to obtain magnesium carbonate crystals. According to the invention, magnesium chloride and urea are taken as raw materials, hexamethylenetetramine is taken as an additive, the nucleation-growth process is directionally regulated by the hexamethylenetetramine additive, and an optimized reaction process is adopted, so that the magnesium carbonate crystal with high purity, good crystallinity and an excellent pore structure is successfully synthesized; the prepared magnesium carbonate crystal has an optimized porous structure. According to the structure, the mass transfer efficiency is effectively improved, diffusion and transmission of substances in the material are facilitated, and the preparation method is simple and has wide application potential.