184 results about "Sodium bisulfate" patented technology

The invention relates to the technical field of oilfield chemistry, and discloses a graft modified cellulose filtrate reducer and a preparation method thereof.The preparation method comprises the following steps that modified hydroxyethyl cellulose, 2-acrylamide-2-methyl propane sulfonic acid, dimethyl diallyl ammonium chloride, alkenylated cardanol and N, N '-methylene bisacrylamide are added into deionized water, stirring is conducted, and a mixture is obtained; the preparation method comprises the following steps: adding cellulose into a reaction kettle, stirring for 10-15 minutes at the temperature of 40-60 DEG C at the speed of 300-400 rpm, dropwise adding ammonium persulfate and sodium hydrogen sulfite into a system, and continuously reacting for 4-6 hours to obtain the grafted modified cellulose filtrate reducer. The filtrate reducer disclosed by the invention has good high temperature resistance and salt resistance.

An animal litter, process for preparing the animal litter, and a method for removal of animal waste using the animal litter are provided. The animal litter generally includes at least one sorbent and a sulfate such as sodium bisulfate. The animal litter is in the form of discrete plural particles which tend to agglomerate when wetted.

An animal litter, process for preparing the animal litter, and a method for removal of animal waste using the animal litter are provided. The animal litter generally includes at least one sorbent and a sulfate such as sodium bisulfate. The animal litter is in the form of discrete plural particles which tend to agglomerate when wetted.

The invention discloses a nickel-containing etching wastewater treatment process, which belongs to the technical field of environmental protection, and comprises a raw water regulating tank, a pH pre-regulating tank, a heterogeneous catalytic oxidation tower, a neutralization coagulation tank, an inclined tube sedimentation tank and a clean water tank which are connected in sequence. According to the process, under the neutral condition, a catalyst loaded with cobalt manganese oxide is used for activating sodium hydrogen persulfate, high-activity sulfate free radicals are generated, a Ni-EDTA complex structure is fractured in a targeted mode, free nickel ions are released in situ, organic ligands are synchronously mineralized, and the adding amount of sodium hydrogen persulfate is dynamically adjusted through a clean water pool closed-loop control system; and high-purity nickel hydroxide precipitate is generated through alkaline precipitation and coagulation, so that efficient solid-liquid separation is realized. The treatment process disclosed by the invention is compact in flow and stable in operation, effectively solves the problems of difficult complex breaking, low nickel removal efficiency, high sludge toxicity, difficult resource recovery and the like when the EDTA complex nickel wastewater is treated by a traditional method, realizes closed-loop recovery of nickel resources, and has the remarkable advantages of low cost, high efficiency and environmental friendliness.

An animal litter, process for preparing the animal litter, and a method for removal of animal waste using the animal litter are provided. The animal litter generally includes at least one sorbent and a sulfate such as sodium bisulfate. The animal litter is in the form of discrete plural particles which tend to agglomerate when wetted.

The preparation method comprises the following steps: adding a sodium hydrogen sulfite aqueous solution and a catalyst into a reaction container, heating, dropwise adding resorcinol diglycidyl ether after the temperature reaches a set value, titrating with an iodine standard solution until the content of sodium hydrogen sulfite is basically unchanged, and ending the reaction. And carrying out reduced pressure suction filtration on the reaction solution to obtain a product, washing the product with ethyl acetate and ethanol, removing resorcinol diglycidyl ether, drying to obtain a crude product, dissolving the crude product in a hydrochloric acid solution, heating in a constant temperature water bath, evaporating SO2, continuously adding a NaOH alcoholic solution, adjusting the pH to alkalescence, filtering to obtain a solid, and drying to obtain the resorcinol diglycidyl ether. According to the invention, sodium hydrogen sulfite and epoxy are subjected to ring-opening reaction to generate the novel hydrophilic chain extender with hydroxyl and sulfonic acid functional groups. Compared with a traditional production mode, the method is simple in reaction condition, rapid in reaction and high in conversion rate, and has a great prospect in hydrophilic chain extension application.

The invention discloses a synthesis method of methyl 4-formylbutyrate, and belongs to the technical field of chemical synthesis, methyl acrylate and nitromethane are subjected to a Michael addition reaction under the action of a catalyst to prepare methyl 4-nitrobutyrate, and the excessive undissolved catalyst can be recycled after being filtered; the method comprises the following steps: under the action of sodium tert-butoxide and potassium permanganate, carrying out hydrolytic oxidation reaction on methyl 4-nitrobutyrate, adding a sodium hydrogen sulfite aqueous solution and a sulfuric acid solution after the reaction is completed, consuming excessive potassium permanganate oxidant, reducing by-products, and carrying out purification treatment to obtain high-purity methyl 4-formyl butyrate. The synthesis method provided by the invention has the advantages of cheap and easily available raw materials, simple operation, easily controllable conditions, high total yield and easy realization of industrial production.

The application provides a weathering steel surface rust layer stabilizing treatment agent for industrial atmospheric environment, and the chemical composition of the weathering steel surface rust layer stabilizing treatment agent is as follows in terms of mass fraction: 25-45% of acrylic resin, 2.0-6.0% of chromium sulfate, 3.0-8.0% of ferrous oxide, 2.0-6.0% of ferric oxide, 0.5-3.5% of copper sulfate, 0.3-1.5% of sodium bisulfite, 1.0-6.0% of sodium molybdate, 0.5-3.5% of nickel sulfate, 2.0-5.0% of potassium phosphate, 0.05-0.5% of surfactant, 0.05-0.5% of defoaming agent, 0.05-0.5% of dispersing agent, 0.05-0.5% of thickening agent, and the balance is water, wherein the amount of plasticizer added is 2-5% of the resin. The stabilizing treatment agent in the application can promote the weathering steel surface to form a stable and dense rust layer within 0.5-1 year after the surface of the weathering steel is treated before use.

The invention belongs to the technical field of synthetic ester, and particularly relates to a preparation method of fatty acid pentaerythritol ester base oil, which comprises the following steps: carrying out esterification reaction on pentaerythritol and fatty acid in the presence of a catalyst and a color retention agent, and carrying out post-treatment to obtain the fatty acid pentaerythritol ester base oil, the catalyst comprises at least one of stannous octoate, stannous oxalate, stannous oxide, tetrabutyl titanate, isopropyl titanate and sodium hydrogen sulfate; the color retention agent comprises at least one of sodium hypophosphite, hypophosphorous acid, activated carbon and sodium sulfite. The color retention agent sodium hypophosphite is matched with the specific catalyst such as stannous oxalate, so that the petroleum color number of the produced fatty acid pentaerythritol ester base oil is smaller, and meanwhile, the esterification reaction time is shorter.

The invention belongs to the technical field of scale inhibitors, and particularly relates to a slow-release scale inhibitor and a preparation method thereof.The preparation method comprises the steps that 3, 4, 5-allyl trihydroxybenzoate, itaconic acid, sodium hydrogen sulfite, methacryloyloxyethyl-n-hexadecyl-dimethyl ammonium bromide and deionized water are mixed, after water bath heating, an ammonium persulfate aqueous solution is slowly added, and the scale inhibitor is obtained after reaction; the preparation method comprises the following steps: dissolving agar in deionized water, adding polyethylene glycol modified sodium alginate and a scale inhibitor into the deionized water, stirring, dropwise adding into edible oil to obtain gel microspheres, adding the gel microspheres into a calcium chloride aqueous solution, slowly stirring, cross-linking, cleaning and drying to obtain the slow-release scale inhibitor. The hydrogel microspheres swell to slowly release the scale inhibitor, meanwhile, the released scale inhibitor is hydrolyzed in water, ester groups are slowly broken, polycarboxylic acid, 3, 4, 5-trihydroxybenzoic acid and hydroxyethyl-n-hexadecyl-dimethyl ammonium bromide are slowly released, and good scale inhibition and corrosion inhibition effects are achieved.

The invention provides a preparation method and device of prothioconazole. The preparation method comprises the following steps: carrying out Grignard reaction on o-chlorobenzyl chloride and magnesium powder in a mixed solvent of toluene and 2-methyltetrahydrofuran; the method comprises the following steps: carrying out Grignard addition reaction on a Grignard reagent and 2-chloro-1-(1-chlorocyclopropyl) ethanone; the preparation method comprises the following steps: carrying out substitution reaction on 1-chloro-2-(1-chlorocyclopropyl)-3-(2-chlorphenyl) propanol and hydrazine hydrate in an alcohol solvent; the preparation method comprises the following steps: carrying out ring closing reaction on 2-(1-chlorocyclopropyl)-1-(2-chlorphenyl)-3-hydrazino-2-alcohol, a formaldehyde solution, a sodium thiocyanate solution and a sodium hydrogen sulfate solution; the preparation method comprises the following steps: carrying out oxidation reaction on 2-(2-chlorocyclopropyl)-3-(2-chlorphenyl)-2-hydroxypropyl)-1, 2, 4-triazolidine-3-thioketone, air and inorganic alkali, so as to obtain prothioconazole. The method can improve the efficiency of the oxidation reaction and the yield and purity of prothioconazole, and is more suitable for industrial production of prothioconazole.

The invention discloses a preparation method and application of a copper powder sintered filter with the surface grafted with antibacterial hydrogel. Firstly, dopamine is used for carrying out surface treatment on the copper powder sintered filter to form a layer of protective film, so that corrosion is prevented, and the protective film can be tightly combined with later hydrogel. The preparation method comprises the following steps: soaking a filter sheet treated by dopamine into an aqueous solution of acrylamide, water-soluble polymer, N, N-methylene bisacrylamide and ammonium persulfate, then adding a mixed aqueous solution of silver nitrate and sodium hydrogen sulfite, uniformly mixing the solution under stirring, and rapidly catalyzing ammonium persulfate by silver ions to generate free radicals to initiate polymerization of acrylamide, so as to obtain the water-soluble polymer filter sheet. Sodium hydrogen sulfite and ammonium persulfate continue to initiate polymerization of acrylamide, the copper powder sintered filter is taken out and cross-linked through calcium nitrate, and the copper powder sintered filter with the antibacterial hydrogel grafted on the surface is obtained and applied to removal of emulsified oil and algae. Part of silver ions in the hydrogel react with copper to obtain nano-silver, and the hydrogel is endowed with good antibacterial performance.

The invention relates to the technical field of chemical synthesis, in particular to a preparation method of 2-sulfydryl-6-chlorobenzoic acid, which comprises the following steps: dissolving chlorobenzoic acid in dimethyl sulfoxide, adding sodium hydrogen sulfite, and stirring at room temperature; the preparation method comprises the following steps: dissolving mercaptobenzoate in dimethyl sulfoxide, adding sodium carbonate and dimethylamino, and reacting at high temperature; cooling to room temperature, and adjusting the pH value to be neutral by using dilute acid; adding into diethyl ether, uniformly mixing, adding into dilute acid, and standing for layering to obtain 2-sulfydryl-6-chlorobenzoic acid; the preparation method of the chlorobenzoic acid comprises the following steps: mixing parachlorotoluene with water, adding a supported catalyst, stirring and heating; after the temperature rises to 80 DEG C, adding potassium permanganate in batches for reaction; and filtering, adjusting the pH value to be acidic by using dilute acid, and then carrying out suction filtration and drying to obtain the chlorobenzoic acid. According to the preparation method disclosed by the invention, chlorobenzoic acid and mercaptobenzoate are subjected to a reaction to obtain 2-mercapto-6-chlorobenzoic acid with high yield; the method has the characteristics of simplified operation, energy consumption reduction, shortened production period and low production cost.

The application discloses a kind of high-altitude area weathering bridge steel member rust layer stabilizing treatment agent and use method, mainly solve the rust layer of high-altitude area weathering bridge steel member is difficult to stabilize and surface rust layer color is not uniform, rust liquid flow and other problems.The stabilizing treatment agent is composed of fast rusting agent and rust layer stabilizer, the fast rusting agent is composed of ferric chloride, copper sulfate, hydrogen peroxide, ethylene glycol and deionized water, the rust layer stabilizer is composed of sodium polyphosphate, sodium bisulfite and methanol and deionized water.The treatment agent of the application is suitable for the harsh environment of low temperature, oxygen is rare, inorganic salt system treatment agent is prone to icing in high sea area, the surface of high-altitude area weathering bridge steel member after processing forms brown rust layer with uniform color, no rust liquid flow.The rust layer of weathering bridge steel member can be stabilized within 8 hours by using the application, the thickness of the rust layer after processing is greater than or equal to 50 μm, the surface rust layer color difference value ΔE of different parts of the component is less than or equal to 10, and the amount of surface rust layer of the component is greater than or equal to 15 g / m 2 .

The invention provides a composition for preservation of vitamin D and vitamin K, an alternative matrix and application, and relates to the technical field of detection reagents. The composition comprises 0.5-3 mol / L of sodium pyrosulfite, 0.5-3 mol / L of sodium hydrogen sulfite and 0.5-3 wt% of lipoprotein lipase, and the technical problems that vitamin D and vitamin K are unstable and prone to failure are solved.

The invention relates to the technical field of high-molecular polymer synthesis, and particularly discloses a cracking method of high-alkalinity polysulfide rubber latex, which comprises the following steps: S1, carrying out mother liquor separation on polysulfide rubber latex, and then washing for 0-2 times to obtain the high-alkalinity polysulfide rubber latex; and S2, cracking the high-alkalinity polysulfide rubber latex into liquid polysulfide rubber by using a cracking agent composed of sodium sulfite, sodium hydrogen sulfite and sodium hydrosulfide, wherein the molecular weight of the liquid polysulfide rubber is 1000-5000. Compared with the prior art, the cracking agent composed of sodium sulfite, sodium hydrogen sulfite and sodium hydrosulfide is adopted, high-alkalinity polysulfide rubber latex can be cracked, the washing frequency is reduced, the process efficiency is improved, and the overall polysulfide rubber production efficiency is indirectly improved; meanwhile, the wastewater discharge amount is reduced, and the subsequent wastewater treatment cost is reduced. The raw materials required by the cracking agent are easy to obtain and low in cost.

The invention provides an environment-friendly low-chlorine wet strength agent and a preparation method and application thereof.The preparation method comprises the steps that adipic acid and tetraethylenepentamine are mixed and react for 2-6 h at the temperature of 170-190 DEG C, and a prepolymer is obtained; cooling the prepolymer to 120-140 DEG C, adding a modifier, carrying out a heat preservation reaction for 2-3 h, and adding deionized water to adjust the solid content to 55-65% so as to obtain a modified polyamide solution; adding a cationizing agent and epoxy chloropropane into the modified polyamide solution, heating to 65-75 DEG C, reacting, and adding acid to adjust the pH value to 2.5-4.5 when the viscosity of the system reaches 50-80 mPa.s; adding sodium hydrogen sulfite, and carrying out heat preservation reaction for 1-2 hours; and adding deionized water to adjust the solid content to 12-13%, thereby obtaining the environment-friendly low-chlorine wet strength agent. The specific modifier is adopted to modify a polyamide main chain, and the cationizing agent is introduced, so that the prepared wet strength agent not only can remarkably reduce the content of organic chlorine in a product, but also can improve the dry and wet strength, water resistance and folding resistance of paper. In addition, the product can also shorten the curing time of the paper.

The invention provides a method for preparing 1, 2, 4-trifluorobenzene, which belongs to the field of fluorine-containing intermediate preparation, and comprises the following steps: (1) adding 2, 4, 5-trifluoroaniline, hypophosphorous acid and a catalyst into dialkyl carbonate to obtain a mixed solution; (2) adding a nitrosyl sulfuric acid solution into the mixed solution obtained in the step (1), and reacting for a certain time; and (3) separating the reaction liquid in the step (2) to obtain the 1, 2, 4-trifluorobenzene. The method has the advantages of simple process, mild reaction conditions, no generation of waste water and sodium bisulfate, recycling of the catalyst, maximum utilization of cuprous oxide, maximum reduction of pollution and full utilization of resources. The conversion rate is as high as 100%, the selectivity is as high as 99% or above, and the product purity is as high as 99.9% or above.

The application discloses a kind of polymer oil displacement agent for carbonate fractured-vug type reservoir and preparation method thereof, step 1, with acetone and ethanol mixed solution as solvent, N, N-dimethylpropylene diamine, diethyl ether and perfluorinated nonanoic acid are added into acetone-ethanol mixed solution, after complete reaction, chloropropene is added, continue to react, after reaction is finished, solvent is removed by evaporation, to obtain fluorocarbon cation hydrophobic monomer CF-1;Step 2, white oil, emulsifier Span80 and Tween80 with mass ratio of 35-45:1-3:1-2 are mixed uniformly to obtain oil phase;AM, sodium p-styrenesulfonate and fluorocarbon cation hydrophobic monomer CF-1 are dissolved in deionized water, sodium bisulfite is added, and stirred uniformly to obtain aqueous solution;The aqueous solution is added to the oil phase to obtain a uniform emulsion, ammonium persulfate is added, and the polymer oil displacement agent is obtained by reaction. It has higher temperature resistance and salt resistance, and greatly reduces the adsorption of carbonate reservoir on the oil displacement agent.

The invention relates to a preparation method of a diformaldehyde gemini surfactant. Mannich reaction is adopted, a long-chain fatty amine component, glyoxal and sodium hydrogen sulfite are used as reaction raw materials, a single variable method is used for controlling reaction conditions, and the optimal conditions of the reaction are explored as follows: the reaction temperature is 60 DEG C, the reaction time is 5 h, and the molar ratio of glyoxal to sodium hydrogen sulfite is 1: 2.3. Then, all products are dissolved with trichloromethane, ethyl acetate is added into the solution to separate out the products, the products are treated through a secondary crystallization method, the product calculation yield is obtained, and the content of 1, 2-bis (dodecyl amino) ethane-1, 2-sodium disulfonate, 1, 2-bis (tetradecyl amino) ethane-1, 2-sodium disulfonate, 1, 2-bis (hexadecyl amino) ethane-1, 2-sodium disulfonate, 1, 2-bis (hexadecyl amino) ethane-1, 2-sodium disulfonate and 1, 2-bis (hexadecyl amino) ethane-1, 2-sodium disulfonate is measured. The synthetic yields of the 1, 2-sodium disulfonate are 65.8%, 67.5% and 76.8% respectively. And characterization is carried out through a nuclear magnetic resonance spectrometer and an infrared spectrometer.

The invention discloses a synthesis method of a thioether compound. The synthesis method comprises the following steps: reacting 3-fluorotoluene with chlorosulfonic acid to obtain 4-fluoro-2-methylbenzenesulfonyl chloride; the preparation method comprises the following steps: dissolving 4-fluoro-2-methylbenzenesulfonyl chloride with acetic acid, adding acetic anhydride and red phosphorus, heating to 80-90 DEG C, adding elemental iodine in batches, and reacting to obtain (2-methyl-4-fluorophenyl) thioacetate; the preparation method comprises the following steps: dissolving (2-methyl-4-fluorophenyl) thioacetate with methanol, adding sodium formaldehyde sulfoxylate and potassium carbonate under the protection of nitrogen, and reacting; cooling the system to room temperature, dropwise adding 2, 2, 2-trifluoroethyl trifluoromethanesulfonate, and reacting to obtain (4-fluoro-2-methylphenyl) (2, 2, 2-trifluoroethyl) sulfane; the preparation method comprises the following steps: dissolving (4-fluoro-2-methylphenyl) (2, 2, 2-trifluoroethyl) sulfane with concentrated sulfuric acid, adding NBS (N-bromosuccinimide), and reacting to obtain (4-fluoro-5-bromo-2-methylphenyl) (2, 2, 2-trifluoroethyl) sulfane.

An animal litter, process for preparing the animal litter, and a method for removal of animal waste using the animal litter are provided. The animal litter generally includes at least one sorbent and a sulfate such as sodium bisulfate. The animal litter is in the form of discrete plural particles which tend to agglomerate when wetted.

The invention relates to the technical field of building materials, and discloses an anti-aging impact-resistant S-shaped filter brick and a preparation method thereof. The preparation method comprises the following steps: mixing kaolin and diatomite, and modifying with vinyltrimethoxysilane to obtain double-bonded composite soil; taking water, sodium hydrogen sulfite, L-ascorbic acid, ammonium persulfate, acrylic acid, triallyl quaternary ammonium salt and the double-bond composite soil, stirring for reaction, filtering, washing and drying to obtain polyacrylic acid modified composite soil; and adding the polyacrylic acid modified composite soil into dimethyl sulfoxide, adding N, N-carbonyldiimidazole, heating to 60-65 DEG C, stirring for 8-12 hours, adding hydroxy propyl cellulose, magnetically stirring at 90-95 DEG C for 3-5 hours, filtering, washing and drying to obtain the modified composite soil. And stirring and mixing the ceramic powder particles, the glycerol modified zeolite, the modified composite soil, cement, a water reducing agent and water, pouring the mixture into an S-shaped filter brick mold, and performing compression molding and maintenance to obtain the anti-aging and impact-resistant S-shaped filter brick.

The invention discloses a reclaimed water reuse process and reclaimed water reuse system aiming at photovoltaic industry wastewater, and the reclaimed water reuse process comprises the following steps: firstly, pumping dilute acid water, dilute alkaline water and concentrated alkaline water into an adjusting tank according to a ratio, adding a reducing agent sodium hydrogen sulfite into the adjusting tank, controlling the ORP (oxidation reduction potential) of the mixed water to be-20-40mV, and controlling the pH value to be 9.0-11.0; mixed water in the adjusting tank is pumped into a reclaimed water recycling device to remove suspended solids, COD and salts, the reclaimed water recycling device comprises a sand filter tank, a carbon filter tank, a precision filter, an ultrafiltration membrane device and a reverse osmosis membrane device which are sequentially connected, produced water of the reverse osmosis membrane device enters a produced water barrel, concentrated water of the ultrafiltration membrane device and concentrated water of the reverse osmosis membrane device enter a concentrated water barrel, and the concentrated water of the ultrafiltration membrane device and the concentrated water of the reverse osmosis membrane device enter the reclaimed water recycling device. The concentrated water in the concentrated water barrel enters the concentrated water treatment unit to be subjected to pH adjustment and defluorination treatment, and finally the concentrated water reaches the standard and is discharged, a large amount of water resources in the photovoltaic industry can be recycled, the water resources are saved, and the system is stable in operation and low in operation cost.

The application relates to the technical field of oilfield chemicals, and discloses a temperature-resistant and salt-resistant cationic hydrophobic association polymer as well as a preparation method and application thereof. Components of the polymer are acrylamide, N,N-dimethyl-N-methyl acryloyloxyethyl-N-2-hydroxy-1-octadecylamino propyl ammonium chloride, ammonium persulfate, sodium bisulfite, a fatty alcohol polyoxyethylene ether and a solvent. The application chemically synthesizes specific amounts of acrylamide, N,N-dimethyl-N-methyl acryloyloxyethyl-N-2-hydroxy-1-octadecylamino propyl ammonium chloride, ammonium persulfate, sodium bisulfite and the fatty alcohol polyoxyethylene ether, and can prepare the polymer with high thickening efficiency. The polymer has good thickening performance, a small critical association concentration, excellent temperature resistance and salt resistance, and can be applied to unconventional oilfields. The product produced by the preparation method has low residual monomer content, the preparation process is simple, the cost is low, the operation is easy, the pollution is small, and the product is easy to be industrially produced.

The invention provides a method and a device for measuring the purity of a medicine for seawater desalination, and the method comprises the following steps: titrating a sodium hypochlorite sample by using a first reducing agent, detecting the change of a platinum electrode in the process, reading the consumption of the first reducing agent when the sodium hypochlorite sample is in redox equilibrium, and calculating the concentration of the first reducing agent; calculating in combination with a formula I to obtain the available chlorine concentration in the sodium hypochlorite sample; titrating the sodium hydrogen sulfite sample by using a second reducing agent, detecting the change of the platinum electrode in the process, reading the consumption of the second reducing agent when the sodium hydrogen sulfite sample is in redox equilibrium, and calculating by combining a formula II to obtain the mass fraction of sulfur dioxide in the sodium hydrogen sulfite sample. According to the present invention, by using the redox titration principle, the mark of the titration end point is accurately set and identified so as to solve the problems of poor detection result accuracy, high reagent consumption, low detection efficiency and tedious operation process of the existing manual titration analysis method.

This invention relates to the field of flocculant technology, and discloses a polyacrylamide flocculant for sludge treatment and its preparation process. The polyacrylamide flocculant for sludge treatment prepared by this invention comprises the following raw materials: water, modified starch, prepolymer, and bromoethane; the prepolymer includes butyl acrylate, water, sodium dodecyl sulfate, acrylamide, N,N-methylenebisacrylamide, glycidyl methacrylate, modified silica, ammonium persulfate, and sodium bisulfite; the modified silica includes vinyltriethoxysilane-modified nano silica; the modified starch includes corn starch, N,N'-(1,2-ethanediyl)bisaspartic acid, sodium alginate, water, sodium sulfate, and phosphorus oxychloride; the obtained polyacrylamide flocculant for sludge treatment has a high molecular weight hyperbranched structure and good flocculation effect.

The invention discloses a method for preparing chromic anhydride from a sodium chromate neutral solution, which comprises the following steps: transferring the sodium chromate neutral solution into a storage tank of an anode head tank by using a pump, adjusting the temperature, transferring a sodium hydroxide solution into a storage tank of a cathode head tank, and adjusting the temperature; overflowing the sodium chromate neutral solution after temperature regulation to an anode chamber of an electrolytic bath and then overflowing to an anode circulating tank, and overflowing the sodium hydroxide solution after temperature regulation to a cathode chamber of the electrolytic bath and then overflowing to a cathode circulating tank; electrifying a cathode plate and an anode plate of the electrolytic bath with direct current to start electrolysis; pumping out an anode solution after electrolysis, adding the anode solution into a reaction kettle after evaporation, adding concentrated sulfuric acid, heating and dehydrating, and standing in a clarifier until layering; the upper layer is sodium hydrogen sulfate, and the lower layer is chromic anhydride liquid, cooling and flaking to obtain the high-quality chromic anhydride. The method can effectively shorten the production period, greatly improve the production yield, reduce the labor intensity of workers, avoid high cost of an electrolytic method and avoid a large amount of byproduct chromium-containing sodium hydrogen sulfate of a sulfuric acid method, and is economical and practical.

The application relates to the technical field of medical nursing products, in particular to a high-air-permeability and high-moisture-permeability medical pad and a preparation process thereof. The non-woven fabric is immersed in a tannic acid solution to obtain a hydrophilic non-woven fabric; the non-woven fabric is sequentially immersed in a dopamine buffer solution and a mercaptopropyl methyl dimethoxysilane to obtain a modified super-hydrophilic non-woven fabric. A high-water-absorption resin is obtained by adding acrylic acid, a sodium hydroxide solution, trimethylolpropane triacrylate, propylene-modified chitosan antibacterial material, potassium persulfate, sodium bisulfite and sodium dodecyl sulfate; and the high-water-absorption resin is laid and formed to obtain an absorption layer. The absorption layer, the modified super-hydrophilic non-woven fabric and the hydrophilic non-woven fabric are sequentially covered on a barrier layer, and are bonded by hot-melt glue hot pressing to obtain a high-air-permeability and high-moisture-permeability medical pad. The medical pad prepared by the application has high air permeability and moisture permeability and good antibacterial performance, and therefore has a wide application prospect in the technical field of medical nursing products.

The invention discloses a continuous preparation method of ethylene glycol dimethacrylate, and aims to provide a continuous preparation method of ethylene glycol dimethacrylate, which is high in reaction rate and high in product yield, and is characterized in that methacrylic acid and ethylene glycol are used as raw materials, and continuous production is realized through reactive distillation; the technical scheme comprises the following steps; the method comprises the following steps: 1, filling a reactive distillation tower with a filler, putting methacrylic acid, ethylene glycol, a polymerization inhibitor and sodium hydrogen sulfate into a feeding tank, and uniformly stirring to obtain a reaction raw material; 2, turning on a main power supply, starting a reaction control system, starting a cyclic heating device, and controlling the temperature of the rectifying column to be 100-120 DEG C; starting a circulating condensing device, and controlling the temperature of condensed water to be 0-10 DEG C; 3, starting a peristaltic pump to pump the reaction raw materials in the feeding tank into the reaction rectifying tower, starting an air pump to introduce air, collecting condensate water at the top of the rectifying tower at the beginning of reaction, and obtaining a crude ethylene glycol dimethacrylate product at the bottom of the rectifying tower; and 4, timely transferring water and methacrylic acid collected at the tower top to a tower top liquid storage tank through a pipeline, and timely transferring an ethylene glycol dimethacrylate crude product collected at a tower kettle to an ethylene glycol dimethacrylate crude product storage tank through a pipeline.