474 results about "Weak base" patented technology

A process for the production of steviosides from Stevia rebaudiana Bertoni includes extraction of comminuted plant material by directly injecting steam into the extractor followed by filtration to get aqueous extract and alkali treatment to remove unwanted compounds in the form of precipitate. The treated aqueous extracted was filtered and the filtrate was first treated with gel or macroporous strong acid cation exchange resin and then with gel or macroporous weak base anion exchange resin. The aqueous eluant containing steviosides was concentrated to obtain purified steviosides.

A series of ultrahigh-cross-linked weakly alkaline-anionic exchange resin with both adsorption and exchange functions, which has different specific surface areas and exchange capacities, is prepared from low-cross-linked macroporous polystyrene through chloromethylation, cross-linking reaction, where the nitrobenzene or substituted nitrobenzene is used as solvent and the Lewis acid is used as catalyst, and amination by dimethylamine.

The invention relates to a production method for electrolytic manganese dioxide. The method comprises the following steps of: A. preparing a mixed liquid of crude manganese sulfate and slurry; B. neutralizing the mixed liquid to remove iron; C. carrying out three-time deep purification on the crude manganese sulfate solution including first purification to remove heavy metals, second purification to remove trace element molybdenum and third purification to remove calcium sulfate and magnesium sulfate; D. electrolyzing; E. rinsing including six steps of washing acid with hot water, rinsing with a weak base, rinsing with a strong base, washing base with hot water, backwashing with a diluted acid and rinsing with hot water; F. milling; and G. mixing to obtain an electrolytic manganese dioxide product. According to the invention, low-grade manganese oxide ore is used as a main raw material to prepare a manganese sulfate solution, the manganese sulfate solution is subjected to deep purification treatment to obtain a high-purity electrolyte, high-performance electrolytic manganese dioxide special for mercury-free alkaline cells and automobile power cells can be respectively produced under different electrolysis conditions, and the obtained electrolytic manganese dioxide product has low impurity content and high quality.

The invention relates to mixed ionic liquid formula solution, which consists of an ionic liquid A, an ionic liquid B and a mixed solvent C, wherein the positive ion of the ionic liquid A is the N,N-dialkyl imidazole positive ion or the N,N,N,N-tetra alkyl quaternary amine positive ion, while the negative ion thereof is the monobasic carboxylic negative ion; the positive ion of the ionic liquid B is the protonated alkylamine positive ion, while the negative ion thereof is the monobasic or binary or ternary carboxylic negative ion; and the mixed solvent C is aqueous solution of water, polyethylene glycol, polyglycol ether, propylene carbonate or tetramethylene sulfone. The mixed ionic liquid formula solution of the invention is strong base-weak acid and weak base-weak acid mixed salt solution, has wide pH buffering capacity, and can greenly efficiently absorb the SO2 gas in a reversible cycle mode. The mixed ionic liquid formula solution of the invention is adopted as a SO2 absorbent so that the requirement for the equipment required by SO2 absorption is simple, the operation condition of absorbing and desorbing SO2 is mild, the desulfurization efficiency is high, and the problems of waste solution and wastewater discharge and the like do not exist. The invention also discloses a preparation method for the mixed ionic liquid formula solution.

The present invention provides a water based lithium secondary battery that can inhibit deteriorations in capacity owing to charge-and-discharge operations and maintain a high capacity even after it is charged and discharged repeatedly. The water based lithium secondary battery includes a positive electrode, a negative electrode, a separator sandwiched between these, and an aqueous electrolyte solution obtained by dissolving an electrolyte made of a lithium salt in a water based solvent. As the water based solvent, a pH buffer solution is employed. The buffer solution is obtained by dissolving an acid and its conjugate base's salt, a base and its conjugate acid's salt, a salt made from a weak acid and a strong base, a salt made from a weak base and a strong acid, or a salt made from a weak acid and a weak base in water.

Production of high-voltage anode anti-corrosion foil is carried out by taking A1 with purity>99.99% and cubic tissue structure>=95% as raw materials, pre-treating, first electrolyzing, first intermediate treating, second electrolyzing, second intermediate treating, third electrolyzing and after-treating. It consists of phosphoric acid, hydrochloric acid, sulfuric acid and nitric acid etc. acid treating liquid, weak base and strong base etc. treating liquid, sulfuric acid, hydrochloric acid, nitric acid, weak-acid chlorine salt and corrosion inhibitor cell liquor. It has good appearance, better electrostatic capacity and capacity difference. It can be used for medium-high voltage section dendritic holes by cell-liquor different properties.

The invention consists of a water treatment process using selective and regenerable weak base anion exchange resins to remove any number of complex anions, especially oxyanions including perchlorate, nitrate, chlorate, arsenate, selenate, and chromate, from aqueous solutions. The treatment process is comprised of three key processes including 1) pretreatment to lower pH, 2) ion exchange, and 3) post treatment to adjust pH and alkalinity. The invention also includes processes for regenerating weak base anion resins and treatment of the residuals generated. This invention employs pressurized treatment, carbon dioxide management, and reuse of regenerating solution to minimize pumping and treatment costs.

The invention relates to a preparation method of triethyl citrate. The preparation method is as follows: by deeply studying the preparation process of triethyl citrate, setting a reaction feed ratio; then adding catalyst to perform reflux reaction; then utilizing phenolphthalein as an indicator and sodium hydroxide to perform titration to determine the reaction end point; utilizing weak base to neutralize less acidic materials in the obtained product, and eluting sodium carbonate with purified water; and finally utilizing activated carbon to decolor, thus obtaining the pure triethyl citrate product. Compared with the prior art, the preparation method provided by the invention has the advantages that the reaction end point is strictly controlled, unnecessary side reactions are reduced, thereduction of the product quality and the waste of cost caused by inadequate reaction or too long reaction time can be avoided; by controlling the temperatures of the processing steps, the damages caused by side reactions are reduced as far as possible; by selecting the decoloring mode, an ideal, colorless and transparent liquid product can be obtained; and the product quality is above the national standard: especially the acid value is controlled to be about 0.2 while the acid value of the national standard is 1.0, and the stability of the product when stored for a long time is higher than those of the like products.

The present invention uses weak base phenylethylene series trialkylamine type anion-exchange resin as fixed phase and uses hydrochloric acid medium as mobile phone to implement coarse separation of platinum, palladium, iridium and gold from base metal, adopts dilute hydrochrolic acid, water and EDTA to elute base metal, and utilizes sulfocyanate+ascorbic acid solution, hydrochloric acid equilibrated methyl isobutanedione, NH4Cl+NH3.H2O solution and HCl+thiourea+thiourea+methyl alcohol solution to selectively shower-wash iridium, gold, palladium and platinum, and its chromatographic column canbe regenerated by using hydrochloric acid. Its resolution is good, the baseline separation can be obtained, and their recoveries are above 95%.

A chemical filter for use within an internal combustion engine lubrication system. The chemical filter employs filtration media including particles having internal pores and interstitial pores formed between adjacent particles. The internal pores and the interstitial pores collectively define filtration media pores, and a strong base material is associated with at least some of the internal pores. The filtration media has a surface area greater than or equal to 25 m²/gm that is derived from filtration media pores that are large enough to receive a combustion acid-weak base complex contained within oil flowing through the chemical filter. This enables an ion-exchange process to occur that immobilizes the combustion acids and regenerates the weak base, so as to extend the time intervals between oil drains, among other benefits.

The invention relates to a method for preparing magnetic spinel ferrite hollow ball in one-step method, which belongs to the technical field of magnetic nano material preparation technology. The preparation method comprises the following steps: utilizing polyatomic alcohol as dissolvent, dissolving tervalence malysite and other divalent inorganic metal salt into polyatomic alcohol, adding right amount of weak base and surface activator, evenly stirring to form brown and transparent mixed solution, placing the solution into a high-pressure stainless steel autoclave which utilizes polytetrafluoroethylene as inside lining, filling volume is 50%-80%, and the solution is sealed in the high-pressure stainless steel autoclave, products are separated by magnets when the solution is reacted 12-24 hours under 160-250 DEG C, the products are washed by water and alcohol, and are dried, thereby getting magnetic spinel ferrite MFe2O4 (M=Co, Ni, Mn, Zn) hollow balls. The method has simple operation, can self-assemble to form a hollow ball structure without templates, does not need subsequent treatment (removal of templates), and is suitable for industrial production of bigger yield, and the products which are got have single material phase and stable property.

A system and method for indication of temperature exposures beyond a set of predetermined limits employs the salts of weak acid-strong base or of a strong acid-weak base compound as reactants. A device includes a housing and capsule. A first reactant and a liquid are included within the capsule. The liquid is chosen such that it expands upon freezing. The capsule is sized such that when the liquid freezes and expands, the capsule fractures. A second reactant is provided within the housing. The location of the second reactant and the method of attaching (if any) the second reactant to the housing may take various forms. When the liquid within the capsule freezes, it expands and fractures the capsule. Upon thawing, the reactant within the capsule escapes and mixes with the reactant located outside the capsule. A second embodiment is a time-temperature indicator. A flexible housing is used, allowing the user to manually deform the housing to fracture a capsule enclosed therein. The reactants combine to produce a color. The color is chosen to be a different color than the housing, allowing a person viewing the indicator device to quickly and easily determine the status of the object being monitored. The threshold temperature at which the device will indicate a changed condition may be varied. Exemplary temperatures include below the freezing temperature, at the freezing temperature, and above the freezing temperature. The capsule composition may be varied such that it melts at a predetermined temperature. Thus, the device may also be used to indicate whether a high temperature has been met or exceeded.

The invention relates to a preparation method for a urea formaldehyde resin used for an environmentally friendly man-made panel. The preparation method comprises the following steps: taking a reaction route of weak base-weak acid-weak base, firstly carrying out the polyaddition of formaldehyde and urea to generate dimethylolurea through a plurality of condensation polymerizations based on the traditional one filling reaction, then carrying out the gradual condensation in an acid medium to generate a linear urea formaldehyde resin, finally gradually adding urea molecules as connection means to improve the length of a linear molecule, reducing the content of free formaldehyde in the urea formaldehyde resin glue, directly synthesizing the green low formaldehyde urea formaldehyde resin glue product, improving the condensation degree and reducing the content of hydroxymethyl, methylene ether and hemiformal through step control, promoting the formation of body type organic micromolecules via microscope, adding a tiny amount of formaldehyde capture agent at the solidification phase to remove residual free formaldehyde, and setting the content of the free formaldehyde in the product to be less than or equal to 0.1 percent, and finally making the product performance technical indicators reach the domestic leading level.

A CO₂ amine scrubbing process uses an absorbent mixture combination of an amine CO₂ sorbent in combination with a non-nucleophilic, relatively stronger, typically nitrogenous, base. The weaker base(s) are nucleophilic and have the ability to react directly with the CO₂ in the gas stream while the relatively stronger bases act as non-nucleophilic promoters for the reaction between the CO₂ and the weaker base. The sorption and desorption temperatures can be varied by selection of the amine/base combination, permitting effective sorption temperatures of 70 to 90° C., favorable to scrubbing flue gas.

The invention relates to a method of treating sexavalent chrome waste water by ion exchange resin, which belongs to the technology of treating the sewage with chrome. The resin used in the method is the polystyrene acyl amidocyanogen weak-base ion-exchange resin. Treating waste water containing chrome by use of the resin includes the following steps that: waste water containing chrome is pretreated to remove the infusible impurities; and then, pretreated waste water passes through the exchange post filled with the ion exchange resin in a flow rate ranging from 3BV/h to 6BV/h in room temperature; the absorbed resin is reproduced by use of the alkali solution with mass fraction ranging from 2 percent to 10 percent, and sexavalent chrome is recycled. After being treated by the invention, the concentration of the sexavalent chrome in waste water drops from 3500mg/L to 0.5mg/L, which can be discharged in comply with the standard; by reproducing, the recovery rate of the sexavalent chrome reaches up to 90 percent to 95 percent, thereby realizing recovering and comprehensively utilizing the resources while treating the waste water.

Provided are a method for preparing a water-soluble polyimide sizing agent for polyimide fiber and application thereof. The method comprises the steps of slowing adding triethylamine, triethanolamine or other weak base reagents into a polyamic acid solution, fully reacting and forming a polyamic acid salt solution; precipitating the polyamic acid salt solution in a poor solvent, and fully removing a remaining solvent and then obtaining polyamic acid salt solid; and dissolving the solid in water to obtain the water-soluble polyimide sizing agent for the polyimide fiber. The polyimide fiber soaked with the sizing agent undergoes the steps of dehydration through a high-temperature heat furnace and imidization to finish fiber sizing. The sizing agent can improve surface energy of fiber, the wettability and interface bonding strength between the sizing agent and resin matrix are improved, the wear resistance and collection property of the fiber can be improved, the high temperature resistance of the fiber in use is effectively guaranteed, and the sizing agent is approximate to zero pollution in the application process and has the use characteristic of environmental friendliness.

The invention relates to the field of geothermal exploitation and provides a leakage-proofing process for exploiting a hot-dry-rock geothermal resource by injecting CO2 ( supercritical carbon dioxide). According to the leakage-proofing process, four inorganic salt precipitation generating mechanisms including (1) mixing a high-concentration salt solution with a precipitation inducer; (2) mixing a high-concentration inorganic salt solution with weak-acid/weak-base gas; (3) mixing a high-concentration inorganic salt solution with another high-concentration inorganic salt solution; (4) evaporating and carrying residual stratum water in surrounding rocks by the supercritical CO2 when the supercritical CO2 flows are adopted, the supercritical CO2 is injected into front slugs/ rear slugs of a hot-dry-rock reservoir stratum alternatively, the slugs are displaced by the supercritical CO2 till to the position close to surrounding rocks in a leaking area, the solutions in the slugs are mixed to generate certain physical-chemical reactions so as to generate precipitation, and the generated precipitation is used to block off rock pore cracks. By the aid of combination of evaporating and carrying functions of the supercritical CO2, the rock pore cracks are further blocked off by the precipitation. The leakage-proofing process for exploiting the hot-dry-rock geothermal resource by injecting the supercritical CO2 is good in effect after being verified by experiments.

A method for completely cleaning high concentration molybdate solution by removing trace tungsten comprises the steps of pre-adjusting pH value of molybdate solution containing trace tungsten, allowing tungstate ions to completely polymerize to form polytungstate ions, and performing selective adsorption of tungsten with adsorption bed filled with macroporous weak base anion exchange resin, so as to completely remove tungsten from molybdate solution.

The invention provides a method for preparing electronic grade ultrahigh purity hydrofluoric acid. The method comprises the following technical steps: (1) pretreating industrial anhydrous hydrogen fluoride; (2) treating in a reboiler; (3) distilling; (4) cooling; (5) absorbing; (6) performing ion exchange adsorption; and (7) filtering. The invention has the following beneficial effects: hydrogen peroxide is used to oxidize As<3+>, thus the problem that As<3+> is difficult to remove can be completely solved; chelating agent and a weak-base anion-exchange resin system are adopted to deeply remove a small amount of metal ions and impurities; through secondary filtration, all the indexes of hydrofluoric acid can meet the requirements of the electronic grade ultrahigh purity agent; and the method of the invention can be used for large-scale production, and the technology is stable, is easy to control and is suitable for popularization.

The present invention is process of separating acetylpropionic acid with active carbon from the mixture solution of acetylpropionic acid and formic acid or acetylpropionic acid containing hydrolysate obtained through hydrolyzing sacchraide. The mixture solution or hydrolysate after being chromatographically separated in alkali cationic column and decolorized in macroporous resin is passed through adsorbing active carbon column to adsorb formic acid, acetylpropionic acid is eluted with water solution of alcohol, and the eluted solution is decompression concentrated to obtain high content acetylpropionic acid product. The present invention has complete separation of acetylpropionic acid from formic acid, high yield, low production cost, easy industrial application and other advantages.

The invention discloses a preparation method of a laser modified titanium dioxide photocatalyst, which belongs to the technique field of environmental pollution treatment and the research field of new energy sources, and the method comprises the following steps: 1) surface treatment of a high-strength and high-elasticity porous polyester fiber net; 2) loading the titanium dioxide photocatalyst; and 3) modification of a titanium dioxide film by laser. The method is to sequentially carry out the protective sorting to the polyester fiber net according to the cleaned fiber net surface, then coat a film on the fiber net surface by using a sol-gel-coating method and taking tetra-iso-propyl titanate and isobutyl alcohol as raw materials under the weak base condition, and modify the film in a textile laser processor. The invention has advantages of extensive sources of raw materials, simple process, low cost, good stability of the prepared titanium dioxide film, and high photo-catalytic activity and efficiency, and has the antifouling, self-cleaning, antibacterial and air-cleaning effects, and the method can be used for the degradation of environmental harmful substance, and can serve as air purification material and dyeing wastewater treatment photocatalysis material.

The present invention is directed to a method of forming titania clad high surface area alumina suitable as a support for forming noble metal catalysts. The resultant catalysts exhibit resistance to poisoning by sulfurous materials and, therefore, are useful in applications directed to internal combustion engine emission conversion and the like. The present invention provides a commercially feasible and cost effective method of forming a highly desired support for noble metal catalyst application. The process comprises forming a slurry of porous alumina particulate suitable as a catalyst support for the intended application, mixing said slurry with a solution of titanyl sulfate having a pH of about 1, increasing the pH of the mixed slurry/solution at a slow rate of from 0.05 to 0.5 pH unit per minute to a pH of ≦4 by the addition of a basic solution, allowing the resultant slurry to age for a period of from 10 to 120 minutes, separating the treated porous alumina particulates and washing same free of sulfate with a weak base, drying and calcining said particulates to produce titania clad alumina particulate product. The resultant material exhibits a normalized sulfur uptake of less than about 45 μg/m²-sample. Such material can subsequently be coated with a noble metal to form the catalyst material.