107 results about "Acid–base titration" patented technology

The electric controller and the neutral titration devices and used to simulate the manual method of the volumetric chemical analysis. The technique used in the invention includes the technique for adding liquid drop in micrometer level, the cleaning technique against mixing multiple flow paths and the technique of PH value and the variable speed control of flow rate addition. The measuring deviceincludes the electric control set, the creepage-metering pump, the stirrer, the pH probe and the temperature compensation probe as well as various control valves and pipes, etc., the invented device can detect the constitutents and concentrations of the acid bath on-line automatically. The detected signals can be transferred to the autoamtic allotment system so as to control the procedure of the acid bath and guarantee the quality of the fibers.

The invention belongs to the field of analysis and testing technology and specifically discloses a determination method for TOC of solid combustible matters. The method comprises the following steps: placing a solid combustible matter sample with certain mass into a combustor (an oxygen bomb) filled with an excess NaOH solution for complete combustion so as to thoroughly oxidize organic carbon into CO2; allowing the NaOH solution to completely absorb CO2 and converting CO2 into Na2CO3; adjusting a pH value to 8.32 by using a hydrochloric acid solution to convert Na2CO3 to NaHCO3; and measuring carbon content in NaHCO3 by using acid-base titration and calculating the TOC value of the solid combustible matter. The method provided by the invention has the characteristics of clear chemical principles, direct carbon measurement, reliable analysis, accurate analysis results, easy and convenient operation, low analysis cost and environmental protection and is applied to determination of TOC of solid combustible matters with complex composition and to related fields.

The invention discloses temperature-sensitive hydrogel and a preparation method thereof, and belongs to the technical field of hydrogel. The preparation method of the hydrogel comprises the followingsteps: (1) preparing reaction solution by using methyl cellulose and deionized water; (2) by using the reaction solution as a solvent, respectively preparing NaHCO3 solution and NaOH solution, and then mixing the NaHCO3 solution and the NaOH solution to carry out acid-base titration on a certain amount of acrylic acid, thus obtaining sodium-acrylate monomeric correction liquid with a PH value being 7.0; (3) adding N-isopropylacrylamide into a four-port bottle according to a certain proportion, and slowly dripping a certain amount of the sodium-acrylate monomeric correction liquid into the four-port bottle under the condition of nitrogen protection, thus obtaining dissolving liquid; (4) adding a crosslinking agnet, an initiator and a catalyst into the dissolving liquid to prepare the temperature-sensitive hydrogel. The temperature-sensitive hydrogel disclosed by the invention has good fire-extinguishing performance.

The invention relates to an experimental method measuring soil respiration via laboratory simulating dry-wet alternate responses. The experimental method at least comprises the following steps: step 1, selecting a wide-mouthed bottle, recording the weight of the wide-mouthed bottle, filling the wide-mouthed bottle with air-dried soil, recording the total weight of the wide-mouthed bottle and the air-dried soil, hanging a desiccant bag in the wide-mouthed bottle, and placing the wide-mouthed bottle in a temperature control system, wherein the wide-mouthed bottle comprises a perforated rubber plug and a glass tube, the perforated rubber plug is arranged at the opening of the wide-mouthed bottle, the glass tube is arranged in the hole of the perforated rubber plug, the top end of the glass tube is sleeved by a latex tube, and the top end of the latex tube is blocked by a flatjaw pinchcock; step 2, measuring gas which is exhausted from soil respiration according an alkali absorption method and an acid-base titration method. The experimental method has the excellent effects that the values of soil respiration within the specified time in the design of different experiments can be achieved, and samples of different numbers can be measured; the operation is simple, convenient and rapid, and the production cost is low; the experimental method can be operated in a common laboratory.

The invention relates to an acid radical detection method for all-vanadium electrolyte. Vanadium is complexed by using EDTA (Ethylene Diamine Tetraacetic Acid)-2Na, then the total number of hydrogen ions in a solution is determined by using a sodium hydroxide acid-base titration method, and by calculating, the acid radical content of an original solution can be obtained. The method is used for rapidly and accurately detecting the concentration of acid radicals. The method comprises the following main steps: 1, taking 0.5 ml of an original solution, and determining the concentration of vanadium in the solution and the concentration of vanadium of each valence state by using a redox potential titration method; 2, taking 0.5 ml of the original solution, adding EDTA-2Na into the original solution, wherein the amount of the EDTA-2Na is 1.1-2 times as much as the amount of a vanadium material; 3, by using an acid-base potentiometric titration electrode, titrating the solution by using a sodium hydroxide solution with a known concentration until a first potential is over completely, so that a total concentration of hydrogen ions is obtained; 4, calculating the concentration of original hydrogen ions according to the valence state and concentration of vanadium; and 5, according to the concentration of vanadium ions and the concentration of original hydrogen ions, calculating a total concentration of acid radicals. According to the method provided by the invention, the concentration of acid radicals in a solution can be determined quickly and accurately so as to provide guidance for the production of electrolyte.

The invention relates to the technical field of experimental instruments, in particular to an automatic acid-base titration instrument, comprising a storage bottle, a titration tube, a vessel, a shell and an intelligent controller. The storage bottle is used for storing acid/alkali liquid; the vessel is used for storing liquid to be titrated; the shell is in a box structure. The storage bottle is fixed the top of an inner chamber of the shell through a fixing base. A vibrator is disposed within the inner chamber of the shell. The vessel is locked and fixed to the vibrator through a fixing clamp. The top end of the titration tube is connected to a liquid outlet of the storage bottle. The bottom end of the titration tube extends into the vessel. An orifice of the bottom end of the titration tube is connected with a sharp-tip titration tube. A micro-metering pump and an automatic valve are mounted on the titration tube in order from top to bottom. A pH sensor is disposed at the bottom of the inner chamber of the vessel. The automatic acid-base titration instrument is convenient to operate, safe and reliable, and time saving and labor saving, and accuracy of experimental results can be ensured.

The invention provides a method for measuring the organic carbon content in the sodium aluminate serosity, relating to the method for measuring the organic carbon content in the sodium aluminate serosity in the process flow of manufacturing aluminium oxide by an ore dressing-Bayer process. The method is characterized in that the test procedures comprises the following steps in sequence: (1) adding sodium aluminate serosity samples to a porcelain boat, adopting a combustion method, taking an acid-washed asbestos as a slipcover, firstly, drying for 30 to 50 minutes at the low temperature, gradually heating up to 900 DEG C, firing for two minutes in the presence of oxygen, absorbing the generated CO2 with potassium hydroxide, and measuring the full carbon contents in the materials with a gas volumetric method; (2) adopting acid base titration to measure the inorganic carbon contents in the measuring sample; and (3) adopting a subtraction method to measure the organic carbon content in the sample. In the method of the invention, appropriate reaction conditions are selected for the materials in the process; the full carbon and inorganic carbon content in the materials are measured in sequence by the gas volumetric method and the acid base titration; the organic carbon content is measured by the subtraction method. The method is simple and effective.

The invention discloses a measurement method for content of hydrofluoric acid in a titanium alloy pickling solution. The titanium alloy pickling solution comprises the main components including nitric acid, the hydrofluoric acid and fluorotitanic acid. The measurement method adopts an acid-base titration method for measuring the content of the fluorotitanic acid, and adopts a calcium fluoride precipitation method for measuring the content of total fluorine in a bath solution; and the content of the fluorine in the fluorotitanic acid is subtracted by the content of the total fluorine to obtain the content of the hydrofluoric acid in the solution. The measurement method has the advantages that the interferences caused by the fluorotitanic acid can be effectively avoided; the adding standard recovery rate of the content of the hydrofluoric acid, measured by adopting the method, is more than 95%; and the determination requirements on the concentration of the hydrofluoric acid are met and the production can be smoothly carried out.

The invention relates to a HPLC (High Performance Liquid Chromatography) quantitative method for cephaeline hydrochloride and ipecine hydrochloride in an ipecacuanha medicinal material and a preparation of ipecacuanha medicinal material. The method is characterized by comprising the following steps: firstly, performing common isocratic elution according to PHLC method, and taking acetonitrile-carbinol-0.1% of phosphoric acid at a volume ratio of (8-9.5):(3-5):(86-88) as a flowing phase, wherein a detecting wavelength is 205nm; and simultaneously measuring the contents of the cephaeline hydrochloride and ipecine hydrochloride in the ipecacuanha medicinal material and a fluid extract, extract and tincture thereof so as to end the history of the measurement of total alkaloids of the ipecacuanha alkaloids in an acid base titration form according to the standard in multiple countries: after performing column chromatography separation for 4 times, respectively measuring the cephaeline hydrochloride and ipecine hydrochloride through delta A at 283nm and 350nm by adopting differential spectrophotometry. According to the method, only acidic aqueous carbinol or aqueous carbinol is used; after fine powder of the medicinal material is ultrasonically extracted or each preparation is diluted, a certain amount of subsequent filtrate is absorbed; and an alumina column is used for removing impurities so as to measure. The method is quick, convenient, accurate and capable of reappearing.

The invention relates to a method for rapidly determining the content of a free acid in a lithium hexafluorophosphate product in a non-aqueous system. According to the method, a water-free supporting electrolyte solution is used as an electrolytic solution; the free acid in the lithium hexafluorophosphate product is titrated with alkaline ions electrolyzed by the electrolytic solution; the content of the free acid in the sample is calculated according to the faraday's law; and the whole detection process can be finished within 5 minutes, and a result can be obtained. With the method of the invention adopted, three bottlenecks, namely, the poor thermal stability of the lithium hexafluorophosphate, interference caused by hydrofluoric acid generated by the reaction of the lithium hexafluorophosphate with water, and little possibility of accurately measuring trace free acids, can be broken; problems such as low precision, low accuracy and long detection time of acid-base titration methods, potentiometric titration methods and etching methods which are commonly used in current industrial production and scientific research can be overcome. The method can be applied to a wide range of samples, can practically promote the analysis and detection levels of fluorine chemical industries and lithium ion battery industries, and further improve the quality of related industrial products.

The invention relates to a method for detecting barium content in barium stearate via a precipitation method. The method comprises the steps of weighing the barium stearate accurately, titrating with a acid-base titration method, collecting precipitated barium sulfate, weighing the barium sulfate after being burned; and then calculating the barium content in the barium stearate. The method is simple and easy to operate. The detected barium content is accurate and reliable.

The invention relates to the technical field of measurement of trace-amount impurities, and particularly discloses a method of measuring content of trace-amount soluble impurities in lithium cobalt oxide. The method at least includes steps of: S1) dissolving a lithium cobalt oxide sample (g) in distilled water and filtering the solution; S2) performing acid base titration to the filtrate in the step S1) by means of an automatic potentiometric titrator, and recording the usage amount of a titration agent and electrode potential change value; S3) according the consumption volume V1 and V2, whichare respectively corresponding to two jumps of the electrode potential change value, of the titration agent, calculating mass percentage of LiOH and Li2CO3 in the lithium cobalt oxide. The method issimple and quick, is free of pollution and is high in precision. The invention provides a scheme for detection of soluble salts in the lithium cobalt oxide at high availability and provides referencefor accurate measurement of contents of trace-amount impurities.

The invention discloses a preparation method of chitosan-based medicine-carrying flexible sponge. The method comprises the following steps: taking chitosan as raw material, dropwisely adding a precipitant sodium hydroxide to obtain chitosan gel precipitate in the process of continuously stirring an acetic acid solution of chitosan, centrifugally cleaning the chitosan gel precipitate, and then mixing the chitosan gel precipitate with a cross-linking agent of oxidizing carboxymethyl cellulose, a plasticizer glycerol and an antibacterial drug tetracycline hydrochloride, and freeze-drying the castfilm to obtain the medicine-carrying flexible sponge body. According to the invention, the chitosan gel precipitate prepared by acid-base titration is used for preparing the sponge body, and the stability of the sponge obtained by freeze-drying is good, and the structure is not damaged when swelling is caused, and one-step molding is carried out, and the structure collapse caused by alkali washing and secondary freeze-drying is avoided, and because of the one-step molding, the chitosan-based medicine-carrying flexible sponge is convenient to carry medicine. According to the invention, glycerol is added as a plasticizer, so that the sponge is soft and elastic. The method has the advantages of short process period, simple and convenient process, low cost and suitability for commercial production.

The invention belongs to the field of analytical chemistry. A sodium dichromate-concentrated sulfuric acid-potassium iodate system serves as an oxidizing agent, the carbon dioxide produced in the reaction is collected by a standardized sodium hydroxide solution, a barium salt serves as a carbonate masking agent, and the content of free carbon in the sample is obtained by an acid base titration method. The device for measuring content of free carbon in boron carbide disclosed by the invention is composed of an oxidizing device, a gas absorption device and a titration device, and is characterized in that the gas absorption device is composed of a group of absorption bottles (1) connected in series and a precipitating bottle (2); the air inlet end of the absorption bottle group is connected with the oxidizing device (3), and the air outlet end of the absorption bottle group is connected with the precipitating bottle (2); the standardized sodium hydroxide solution (4) is filled in the absorption bottle; and a mixed solution (5) of barium chloride and sodium hydroxide is filled in the precipitating bottle. The device is simple in structure, convenient to use, high in gas circuit sealing property and high in reliability. According to the measurement method, the endpoint is easy to observe, the operability is high, the data repeatability is high, and the accuracy is high. The device and the method are suitable for detection of the free carbon in the boron carbide.

Carbon dioxide, methane, nitrous oxide and three groups of fluorinated gases have been referred to as greenhouse gases and the most offensive gases in contributing to Global Warming This invention comprises the use of Titration and other chemical oxidation—reduction reactions in novel ways to scrub these gases from the Earth's atmosphere. The invention comprises identifying, developing, and spraying base aerosols to neutralize carbon dioxide, nitrous oxide, sulphur dioxide, and similar compounds whose oxides form acids when dissolved in water vapor. Acid-base titrations result in neutralization of the acid and the base. The formation of a salt and water typically are by-products. Salt precipitates such as CACO3—calcium carbonate or limestone settle into the oceans naturally forming limestone deposits which act as homes for microscopic sea life. Carbonic acid which results from CO2 being dissolved in water produces calcium carbonate when treated with a base. The invention proposes that by trials other natural salts may be identified which may safely be precipitated to the earth as it is important that the absorption into the Earth's environment occur with a minimum of deleterious effects. There exists a number of acids and The invention further comprises the novel use of vehicles such as space shuttles or a space station as delivery vehicles.

The invention belongs to the field of novel additives for petrochemical engineering, and particularly relates to a clean type diesel oil pour point depressant and a preparation method thereof. The clean type diesel oil pour point depressant is prepared from acid anhydride, long-carbon-chain fatty acid and low-carbon alcohol. The concrete preparation method comprises the following steps: (1) taking 25.0 to 28.0 parts by mass of the acid anhydride; (2) adding 43.0 to 45.0 parts by mass of the low-carbon alcohol; heating and stirring until mutual dissolution is realized; (3) measuring an esterification rate by an acid-base titration method; (4) after a period of time, adding 27.0 to 29.0 parts by mass of the long-carbon-chain fatty acid, thus obtaining a target product. Solvents and catalysts are not used; the materials are economic; the effects of cleanness and environment protection are achieved. A pour point depressant formula is applicable to better flow performance improvement when diesel oil is at low temperature; the requirements of cleanness and environment protection of combusted tail gas exhaust in the diesel oil combustion process of a diesel engine can be particularly met.

The invention discloses a method for assaying residual acid of nitroglycerin, belonging to the field of inorganic chemical analysis. The method comprises the following steps of: extracting alkaline liquid from the nitroglycerin by using water; completely dissolving the extracted nitroglycerin by using a neutral organic solvent which is a mixture of nitroglycerin and water; and assaying the residual acid content of the dissolved nitroglycerin by an acid base titration method. The invention relates to a method for assaying the residual acid (nitric acid and sulfuric acid) of the nitroglycerin.