80 results about "Perfluorinated carboxylic acid" patented technology

The invention relates to a fiber-reinforced perfluorinated ion exchange membrane containing a non-continuous nano-pore canal and a preparation method thereof. A basic membrane of the membrane comprises a perfluorosulfonic acid ion exchange resin layer and a perfluorocarboxylic acid ion exchange resin layer, reinforcing fiber mesh cloth is arranged in the perfluorosulfonic acid resin layer, and gas release coatings are sprayed on the surfaces on the two outer sides of the basic membrane; and the fiber-reinforced perfluorinated ion exchange membrane is characterized in that the non-continuous nano-pore canal is further contained in the perfluorosulfonic acid resin layer. The membrane is prepared through a melting co-extrusion or multi-layer hot-pressing compounding process. The membrane is used for the ion exchange membrane in the chlor-alkali industry and has better mechanical properties and electrochemical properties.

The invention relates to the technical field of ionic membranes, and particularly relates to an ionic conductive membrane for a chlorine-alkali industry and a preparation method thereof. The ionic conductive membrane comprises a perfluorinated ion exchange resin base membrane, a micro-porous reinforcing material and a surface layer of a perfluorinated ion exchange resin microparticle. The perfluorinated ion exchange resin microparticle is a mixture of one or two of a perfluorinated carboxylic acid resin microparticle or perfluorinated sulfonic acid-carboxylic acid copolymer resin microparticle and a perfluorinated sulfonic acid resin microparticle, wherein the perfluorinated sulfonic acid resin microparticle accounts for 95%-50% of the percentage by mass of the mixture. The surface layer of the ionic conductive membrane has good compatibility and adhesion and maintains a good degassing effect in the whole service life of the ionic conductive membrane. An alkali metal chloride solution of which the range of concentration is wide can be efficiently and stably treated by the ionic conductive membrane in the chlorine-alkali industry, and the ionic conductive membrane is applicable for running in a zero-pole electrolytic cell under a novel high current density condition and a very excellent product purity index is achieved. The invention also provides a preparation method of the ionic conductive membrane, the process is simple and reasonable and industrial production is easily achieved.

The invention relates to a hole-containing fiber reinforced ion exchange membrane for the chlor-alkali industry and a preparation method thereof. The membrane is a multi-layer composite membrane composed of a perfluorinated sulfonic acid ion exchange resin layer, a perfluorinated carboxylic acid ion exchange resin layer, a reinforced mesh and a gas release coating, wherein the perfluorinated sulfonic acid resin layer contains reinforced fibers and nano holes. The membrane is prepared through a melt coextrusion or multi-layer hot pressing composite process. The membrane can be used as an ion exchange membrane for the chlor-alkali industry, and has good mechanical properties and electrochemical properties.

The invention belongs to the technical field of ion membranes and specifically relates to an ion-conducting membrane and a preparation method thereof. The ion-conducting membrane comprises a perfluorinated ion-exchange resin-based membrane, a porous reinforced material and a perfluorinated sulfonic acid resin micro-particle surface layer. The perfluorinated ion-exchange resin-based membrane comprises a resin layer which is mainly composed of perfluorinated sulfonic acid resin and another resin layer which is mainly composed of perfluorinated carboxylic acid resin. The surface layer of the ion-conducting membrane provided by the invention has good compatibility and adhesion, so that the good degassing effect throughout the whole life of the ion-conducting membrane can be ensured. When used in the chlor-alkali industry, the ion-conducting membrane is capable of treating an alkali metal chloride solution in a wide concentration range stably and efficiently; and the ion-conducting membrane is suitable for operation in a zero-polar distance electrolyzer under high current density condition and has very excellent product purity index. The invention further provides the preparation method thereof, the process is simple and reasonable and the industrial production is easy to realize.

The invention relates to N-alkylamino-2-perfluoroalkylimidazoline quaternary ammonium salt and a preparation method thereof. The N-alkylamino-2-perfluoroalkylimidazoline quaternary ammonium salt has molecular structural formulas shown as a formula (1) and a formula (2), wherein R1 is CF3-(CF2)n, and n is between 3 and 11; and R2 is one of C1-10 alkyl, C2-10 alkenyl, C3-7 cycloalkyl or any substituted aryl group, aralkyl group or heteroaryl group. The preparation method comprises the steps of: reacting polyenoid polyamine and perfluorocarboxylic acid serving as raw materials, and aluminum oxide, heteropolyacid, heteropolyacid / aluminum oxide, and phosphotungstic acid / mesoporous yttrium aluminum oxide serving as a catalyst for 7 to 12h at the temperature of between 90 and 150 DEG C to obtain fluorocarbon imidazoline, and then reacting the fluorocarbon imidazoline with a quaternization agent in a molar ratio of 1: (1-3) for 6 to 12h at the temperature of between 60 and 150 DEG C to obtain the N-alkylamino-2-perfluoroalkylimidazoline quaternary ammonium salt. The method has the characteristics of mild reaction conditions, high yield, less three wastes, easily obtained raw materials, suitable industrialized production and 'environment-friendly chemical' synthesis.

The invention relates to a carbon-nanotube-modified high-current-density perfluorinated ion exchange membrane and a preparation method thereof. According to the membrane, a carbon-nanotube-containing perfluorosulfonic acid ion exchange resin layer and a perfluorocarboxylic acid ion exchange resin layer constitute a basal membrane, a reinforcing mesh is arranged to the surface or inside of the basal membrane, and a 3-12-micrometer gas release coating is respectively coated on two side surfaces of the basal membrane, wherein the perfluorosulfonic acid resin layer contains 0.1-10 wt% of carbon nanotubes, the thickness of the perfluorosulfonic acid resin layer is 80-150 micrometers, and the thickness of the perfluorocarboxylic acid resin layer is 8-15 micrometers. The membrane can be prepared by a melt coextrusion or multilayer hot-press compounding technique. The membrane can be as an ion exchange membrane in chlor-alkali industry, is especially suitable for a superhigh-current-density electrolysis technique, and has favorable mechanical properties and electrochemical properties.

The present invention relates to a micro-nano pore-containing chlorine-alkali ion membrane preparation method, which comprises: adopting monovalent alkali metal chloride MCl ultra-fine powder as a sacrifice core material, adding to a perfluorosulfonic acid resin powder material, completely mixing, carrying out melting extrusion to obtain a MCl-containing perfluorosulfonic acid resin master batch, carrying out a melting co-extrusion or multi-layer hot pressing compounding process on the MCl-containing perfluorosulfonic acid resin master batch and the perfluorosulfonic acid resin to prepare a perfluorinated ion exchange resin base film, placing a reinforcing mesh cloth into the surface or the internal of the prepared perfluorinated ion exchange resin base film to form a reinforced ion membrane, carrying out hydrolysis transformation, carrying out double side spraying on the transformed ion membrane to form a gas release coating, and carrying out standing aging in a sodium hydroxide aqueous solution to obtain the finished product. The membrane can be used for the ion exchange membrane in the chlorine-alkali industry, especially for the 6-8 kA / m<2> ultra-high current density chlorine-alkali electrolysis process, and has the good mechanical property and the good electrochemical property.

The invention belongs to the technical field of polymer materials and specifically relates to an ion exchange membrane for electrolysis of an oxygen cathode and a preparation method thereof. The ion exchange membrane for electrolysis of the oxygen cathode is a multi-layer composite membrane comprising a perfluorosulfonic acid ion exchange resin layer, a perfluorocarboxylic acid ion exchange resin layer, a reinforcing mesh fabric, a hydrophilic coating and a multifunctional coating, wherein the thickness of the perfluorosulfonic acid resin layer is 80-150 mu m, the thickness of the perfluorocarboxylic acid resin layer is 8-15 mu m, the hydrophilic coating with the thickness of 3-12 mu m is coated on the surface on the anode side of the membrane, and the multifunctional coating with the thickness of 3-12 mu m is coated on the surface on the cathode side of the membrane. The preparation method comprises the following steps: spraying the carboxylic acid side of the ion membrane after transformation by using a dispersion solution containing perfluorosulfonic acid resin, a catalyst and a lower alcohol and drying to form the multifunctional coating. According to the preparation method provided by the invention, the surface of the ion membrane is endowed with a catalytic structure and the function, oxygen is in full contact with the surface of the ion membrane, and reaction is performed on the surface, so that the cell voltage is reduced and the catalytic efficiency is simultaneously improved.

The invention relates to an ion exchange film operated under an ultrahigh current density condition and a preparation method of the ion exchange film. The film is a three-structure composite film which consists of a perfluorinated sulfonic acid resin film with high exchange capacity, a perfluorinated hot melting adhesive high-elastic film with the low molecular amount and the thickness of 1-30 microns and a perfluorinated carboxylic acid resin film with low exchange capacity. By the composite film, an enhanced ion exchange film is formed by using a fiber mesh or a microporous film. The invention also provides a method for preparing the ion exchange film, solves the problem of stripping and deformation caused by large ion flux difference between the sulfoacid film with the high exchange capacity and the carboxylic acid film with the low exchange capacity under a high current density condition, and has high electrolysis performance under a condition that the operation speed is up to 6-20KA / m<2>.

The invention relates to an ion exchange membrane for superhigh-current-density oxygen cathode electrolysis and a preparation method thereof. The ion exchange membrane is a multilayer composite film composed of a perfluorocarboxylic acid ion exchange resin layer, a carbon-nanotube-containing perfluorosulfonic acid ion exchange resin layer, a reinforcing mesh, a sulfonic acid side gas release coating and a carboxylic acid side multifunctional coating, wherein the total thickness of the basal membrane of the perfluorinated ion exchange membrane is 90-180 micrometers, the thickness of the perfluorosulfonic acid resin layer is 80-160 micrometers, the thickness of the perfluorocarboxylic acid resin layer is 8-16 micrometer, and the thickness of the two side surface coatings of the membrane is respectively 3-12 micrometers. The membrane can be prepared by a melt coextrusion or multilayer hot-press compounding technique. The membrane is used for an oxygen cathode electrolysis technique, is especially suitable for ion-exchange-membrane-process caustic soda production by a superhigh-current-density oxygen cathode electrolysis technique, and has favorable mechanical properties and electrochemical properties.

The invention belongs to the technical field of determination of pollutants and discloses a method for determining a perfluorocarboxylic acid compound in crops. The method comprises the following main steps: freezing, drying and crushing crops to be detected, so as to obtain a sample; adding internal standard substances 13C4-PFOA (Perfluorooctanoic Acid) and 13C2-PFDA (Perfluorononanoic Acid) into the sample; after uniformly mixing, adding an extracting agent; carrying out ultrasonic extraction to obtain an extracted substance; after purifying the extracted substance through solid phase extraction of a WAX small column filled with graphite carbon black; determining by adopting a high performance liquid chromatography tandem quadrupole linear ion trap mass spectrometer; comparing with perfluorocarboxylic acid standard products which are operated in parallel, so as to carry out quantitative treatment by retention time and optimized ion characteristics; characteristic ions with less base material background interference, good peak shape and high noise to signal ratio are used as quantitative ions and are quantified through an internal standard method. The method disclosed by the invention has the advantages of high recovery rate, good precision and high sensitivity, is used for resisting complicated base material interference and is applicable to determination of the perfluorocarboxylic acid compounds in cereals, root vegetables, leaf vegetables and fruit vegetables.

The present invention relates to a process for producing fluorinated aliphatic compounds by pyrolysis of perfluorocarboxylic acids and their derivatives-halides and esters. The pyrolysis is carried out in the presence of a catalyst consisting of a carrier most preferably selected from the series comprising active carbon, magnesium oxide, calcium oxide, barium oxide, zinc oxide, aluminum oxide, nickel oxide, oxides of silicon promoted with alkali metal halides, selected from the series comprising fluorides, chlorides bromides, iodides of sodium, potassium, rubidium, cesium, at a temperature in the range of from about 100° C. to about 450° C.; with producing fluorinated aliphatic compounds selected from the series comprising perfluoroolefins, polyfluoroolefins and their derivatives; and also in the presence additionally of hydrogen fluoride with the formation of fluorinated aliphatic compounds selected from the series comprising polyfluoroalkanes and their derivatives.

The invention discloses a treatment method of perfluoroalkyl acyl fluoride waste. The method comprises the following steps of: first, adding aqueous alkali to the perfluoroalkyl acyl fluoride waste, adjusting the pH value to 7-8, standing and separating to obtain a water phase and an oil phase; then, separating and purifying the water phase to obtain perfluorocarboxylate; and finally, separating and purifying the oil phase to obtain inertial fluorocarbon. The perfluoroalkyl acyl fluoride waste is treated in grades in the following steps of: adding aqueous alkali to separate the perfluoroalkyl acyl fluoride waste into the water and oil phases, and respectively separating and purifying the water and oil phases; and obtaining high purity perfluorocarboxylate after separation and purification of the water phase and obtaining high purity inertial fluorocarbon after separation and purification of the oil phase. The treatment condition is mild and the treatment effect is good.

A RE metal contained perfluorocarboxylic acid-Lewis acid catalyst suitable for FBC technique and the catalyzing in organic phase is prepared through the reaction between RE metal oxide, acetate, carboxyl compound, halide sulfate or nitrate and perfluorocarboxylic acid. Its advantages are high stability in air, high catalytic activity and easy recovery.

The invention discloses a preparation method for perfluoroalkyl iodide with low carbon number. According to the method, under the effect of an anhydrous perfluorocarboxylic silver salt RfCO2Ag and / or an anhydrous perfluorocarboxylic copper salt (RfCO2)2Cu, an anhydrous perfluorocarboxylic acid salt (RfCO2)nM and elementary iodine are subjected to a thermal decomposition reaction to generate the perfluoroalkyl iodide, wherein Rf is independently selected from perfluoroalkyl having carbon atoms of 1-6, n is selected from an integer of 1-6, M is a IA group metal element, a IIA group metal element, a IVA group metal element, a IB group metal element or a IIB group metal element metal. According to the present invention, the preparation method has characteristics of no requirement of the solvent, simple operation, mild reaction, rapid reaction speed, high yield, low cost, high selectivity and environmental protection, and can be used for the industrial production; the prepared perfluoroalkyl iodide can be used for production of fluorine-containing finishing agents, fluorine-containing surfactants and other fluorine-containing fine chemical products.

The invention relates to an ion exchange film operated under an ultrahigh current density condition and a preparation method of the ion exchange film. The film is a three-structure composite film which consists of a perfluorinated sulfonic acid resin film with high exchange capacity, a perfluorinated hot melting adhesive high-elastic film with the low molecular amount and the thickness of 1-30 microns and a perfluorinated carboxylic acid resin film with low exchange capacity. By the composite film, an enhanced ion exchange film is formed by using a fiber mesh or a microporous film. The invention also provides a method for preparing the ion exchange film, solves the problem of stripping and deformation caused by large ion flux difference between the sulfoacid film with the high exchange capacity and the carboxylic acid film with the low exchange capacity under a high current density condition, and has high electrolysis performance under a condition that the operation speed is up to 6-20KA / m<2>.

The invention discloses oxa perfluorocarboxylic acid dipentaerythritol ester and preparation and application thereof. The oxa perfluorocarboxylic acid dipentaerythritol ester is one compound shown as a structural formula (I) or is a mixture of two or more compounds shown as the structural formula (I), in the structural formula (I), R<1>, R<2>, R<3>, R<4>, R<5> and R<6> are respectively and independently H or F(CF3CFCF2O)nCF(CF3)CO-, n is a natural number, and R<1>, R<2>, R<3>, R<4>, R<5> and R<6> are not all H. A synthetic method of the oxa perfluorocarboxylic acid dipentaerythritol ester is shown as the following reaction equations (in the specification). The invention also provides the application of the oxa perfluorocarboxylic acid dipentaerythritol ester as a surfactant, and the oxa perfluorocarboxylic acid dipentaerythritol ester is high in surface activity, can be directly used as a fluorocarbon surfactant, and can be widely used in the fields of brightening agents, waterproof and oilproof agents of fiber fabrics including leather and paper, waterproof and oilproof agents of hard surfaces, and the like.

The invention, which belongs to the technical field of chemical detection, particularly relates to a detection method of a perfluorocarboxylic acid compound. The method comprises the following steps:(1), carrying out a derivatization reaction on perfluorocarboxylic acid by taking bis(dimethylamino) methoxymethane as a derivatization reagent, and deriving the perfluorocarboxylic acid into bis(dimethylamino) methyl perfluorosubstituted alkane; (2), performing quantitative detection by adopting a gas chromatography-tandem mass spectrometry method; to be specific, setting the sample to be perfluorocarboxylic acid extracted from a target substance to be detected after a target substance is purified and enriched by combining an alkali digestion method and solid-phase extraction. The perfluorocarboxylic acid is perfluorocarboxylic acid with the carbon atom number of 2-20, and preferably, the perfluorocarboxylic acid is perfluorocarboxylic acid with the carbon atom number of 4-12.

The invention relates to an electrolytic cell diaphragm for the chlor-alkali industry and a preparation method thereof, and belongs to the technical field of ion exchange membranes. According to the electrolytic cell diaphragm and the method, the diaphragm comprises a base membrane, functional surface coatings are arranged on the two faces of the base membrane, the base membrane is composed of a perfluorosulfonic acid polymer layer and a perfluorocarboxylic acid polymer layer, and the functional surface coatings are of porous rough structures composed of perfluorinated ionic polymers. According to the electrolytic cell diaphragm and the method, the adhesive force of the surfaces of the diaphragm to bubbles is reduced, the effective electrolysis area of the surfaces of the diaphragm is increased, a local polarization phenomenon is reduced, the electrolytic cell diaphragm is suitable for operation in a novel zero-polar-distance electrolytic cell under a high-current density condition, the cell voltage can be remarkably reduced, and energy consumption is reduced; the invention also provides the simple and feasible preparation method.

The invention belongs to the technical field of ion exchange membranes, and particularly relates to a novel low-resistance ion conduction membrane for the chlor-alkali industry and a preparation method thereof. The low-resistance ion conduction membrane consists pf a first perfluorosulfonic acid-perfluorocarboxylic acid polymer composite layer, a second perfluorosulfonic acid-perfluorocarboxylic acid polymer composite layer, a perfluoropolymer reinforcing net and a functional surface coating, wherein the functional surface coating is of a porous rough structure formed by a mixture of a perfluorinated ionic polymer and a metal oxide; and the perfluoropolymer reinforcing net is formed by compounding and weaving a non-woven polymer and protein fibers. According to the novel low-resistance ionconduction membrane, a small amount of perfluorocarboxylic acid is added into the perfluorosulfonic acid layer so that the current efficiency of the membrane is improved, and the membrane resistanceis reduced by adding a small amount of perfluorosulfonic acid into the perfluorocarboxylic acid layer; the perfluoropolymer reinforcing net is adopted as a reinforcing material, so that the membrane resistance is reduced; the dosage of inorganic oxides or fluorine-containing particles in a traditional coating is reduced, and the resistance of the composite membrane body is reduced, facilitating rapid ion transmission.

The invention belongs to the technical field of ion exchange membranes, and particularly relates to a novel low-resistance chlorine-alkali industrial ion conduction membrane and a preparation method thereof. The membrane is composed of a first perfluorocarboxylic acid-perfluorosulfonic acid polymer composite layer, a second perfluorocarboxylic acid-perfluorosulfonic acid polymer composite layer, aperfluoropolymer reinforcing net and a functional surface coating, wherein the functional surface coating is of a porous rough structure formed by a perfluorinated ionic polymer, and the perfluorinated polymer reinforcing net is formed by compounding and weaving a non-woven polymer and protein fibers. According to the novel low-resistance chlorine-alkali industrial ion conduction membrane, a small amount of perfluorocarboxylic acid is added into a perfluorosulfonic acid layer, so that the current efficiency of the membrane is improved; the membrane resistance is reduced by adding a small amount of perfluorosulfonic acid into the perfluorocarboxylic acid layer; a perfluorinated polymer reinforcing net is adopted as a reinforcing material, so that the membrane resistance is reduced; and theuse amount of inorganic oxide or fluorine-containing particles in a traditional coating is reduced, the surface resistance of the composite membrane is reduced, and rapid ion transmission is facilitated.

The present invention relates to a process for producing fluorinated aliphatic compounds by pyrolysis of perfluorocarboxylic acids and their derivatives-halides and esters. The pyrolysis is carried out in the presence of a catalyst consisting of a carrier most preferably selected from the series comprising active carbon, magnesium oxide, calcium oxide, barium oxide, zinc oxide, aluminum oxide, nickel oxide, oxides of silicon promoted with alkali metal halides, selected from the series comprising fluorides, chlorides bromides, iodides of sodium, potassium, rubidium, cesium, at a temperature in the range of from about 100° C. to about 450° C.; with producing fluorinated aliphatic compounds selected from the series comprising perfluoroolefins, polyfluoroolefins and their derivatives; and also in the presence additionally of hydrogen fluoride with the formation of fluorinated aliphatic compounds selected from the series comprising polyfluoroalkanes and their derivatives.

The invention belongs to the technical field of polymer materials and specifically relates to an ion exchange membrane for electrolysis of an oxygen cathode and a preparation method thereof. The ion exchange membrane for electrolysis of the oxygen cathode is a multi-layer composite membrane comprising a perfluorosulfonic acid ion exchange resin layer, a perfluorocarboxylic acid ion exchange resin layer, a reinforcing mesh fabric, a hydrophilic coating and a multifunctional coating, wherein the thickness of the perfluorosulfonic acid resin layer is 80-150 mu m, the thickness of the perfluorocarboxylic acid resin layer is 8-15 mu m, the hydrophilic coating with the thickness of 3-12 mu m is coated on the surface on the anode side of the membrane, and the multifunctional coating with the thickness of 3-12 mu m is coated on the surface on the cathode side of the membrane. The preparation method comprises the following steps: spraying the carboxylic acid side of the ion membrane after transformation by using a dispersion solution containing perfluorosulfonic acid resin, a catalyst and a lower alcohol and drying to form the multifunctional coating. According to the preparation method provided by the invention, the surface of the ion membrane is endowed with a catalytic structure and the function, oxygen is in full contact with the surface of the ion membrane, and reaction is performed on the surface, so that the cell voltage is reduced and the catalytic efficiency is simultaneously improved.

Efficient skin disinfection solution is prepared from the following raw materials in parts by weight: 6 to 8 parts of chitosan quaternary ammonium salt, 4 to 7 parts of povidone iodine, 6 to 12 parts of lonicera japonica, 5 to7 parts of lavender, 4 to 5 parts of sucrose palmitate, 2 to 4 parts of perfluorocarboxylic acid salt, 4 to 7 parts of surfactants, 2 to 4 parts of radix sophorae flavescentis, 3 to 5 parts of myosoton aquaticum, 3 to 4.5 parts of arisaema fargesii, 4 to 8 parts of myristic acid isopropyl ester, 3 to 5 parts of isopropyl alcohol, 10 to 14 parts of distilled water, and 4 to 8 parts of ethyl alcohol. The efficient skin disinfection solution has the beneficial effects that bacteria on the skin can be killed very well, no pungent smell exists and the comfortableness is relatively good.

The invention relates to a reinforced low-resistance chlor-alkali perfluorinated ion exchange membrane and a preparation method thereof, and belongs to the technical field of ion exchange membranes. The ion exchange membrane comprises a base membrane, wherein functional surface coatings are arranged on the two surfaces of the base membrane, the base membrane is composed of a perfluorosulfonic acidpolymer layer and a perfluorocarboxylic acid polymer layer, a reinforcing material net is arranged in the perfluorosulfonic acid polymer layer, a hollow tunnel is arranged in the perfluorosulfonic acid polymer layer, and the functional surface coating is of a porous rough structure formed by a mixture of a perfluorinated ionic polymer and a metal oxide. According to the ion exchange membrane of the invention, the resistance of the membrane body is reduced, rapid conduction of ions is facilitated, the adhesive force of the surface of the membrane to bubbles is reduced, the effective electrolysis area of the surface of the membrane is increased, the local polarization phenomenon is reduced, the membrane is suitable for running in a zero-polar-distance electrolytic cell under a novel high-current-density condition, the cell voltage can be remarkably reduced, and the energy consumption is reduced. The invention also provides a simple and feasible preparation method.

The invention discloses a perfluorinated ion exchange fiber with the following structure and a preparation method thereof. The iron exchange fiber is produced with perfluorinated sulfonic acid fiber forming resin or perfluorinated carboxylic acid fiber forming resin by a melting spinning method, the monofilament strength of which can reach 30Mpa and the use temperature of which can exceed 150 DEG C. The fiber can be used in water purification and filtration, metal iron absorption and catalyzer preparation, etc. In the iron exchange process, the absorption speed of the fiber is fast and the absorption volume can reach over 1meq / g, meanwhile, the washing and taking off of the fiber which can be repeatedly regenerated for use are easy. The preparation method of the fiber is simple, easy for operation and has few technical devices. In addition, m is an integer from 0 to 3, n is a whole number that is more than or equal to 2, x is a whole number from 1 to 20 and y is a whole number from 1 to 5. And R is SO3M or COOM and M is H, Na, K, Li, Mg or Ca.

The invention relates to an instrumental analysis pretreatment method of enriching a perfluorinated carboxylic acid compound and belongs to the technical field of analysis and detection. The pretreatment method comprises the steps of preparing a DFA solution, a DCC solution and a standard solution, activating a magnetic graphite oxide material, performing incoming magnetic separation after derivatization treatment, blow-drying and dissolving collected desorption liquid, and then performing online detection. The treatment method is simple and quick, has good selectivity for the perfluorinated carboxylic acid compound, is high in enrichment time and reusable, can reduce sample loss and improves detection accuracy.

The invention discloses a modification method for removing perfluorocarboxylic acid in water by reinforced activated carbon, which comprises the following steps: (1) pretreating activated carbon, the pretreatment process comprising alkali washing and acid washing; (2) transferring the activated carbon pretreated in the step (1) into a graphene oxide solution to prepare graphene oxide loaded activated carbon; and (3) transferring the graphene oxide loaded activated carbon into a sulfite solution or a hydrosulfite solution, reacting under the condition of ultraviolet irradiation, and performing reduction modification to prepare the modified activated carbon. According to the method, the adsorption efficiency of the activated carbon on the perfluorocarboxylic acid is enhanced by regulating the polarity of the surface of the activated carbon, and after the activated carbon is modified by adopting the method, the removal rate of the perfluorocarboxylic acid in water is remarkably increased. The modification method disclosed by the invention is simple and efficient, mild in reaction condition, low in equipment requirement, green and environment-friendly and free from secondary pollution, and the prepared modified activated carbon has a good removal effect on perfluorocarboxylic acid in water.

The invention discloses a preparation method of tetramethylammonium hydroxide. According to the method, a double-chamber single-membrane electrolytic cell is adopted, a ruthenium dioxide titanium substrate serves as an anode of the electrolytic cell, stainless steel serves as a cathode of the electrolytic cell, a cell body is made of a polytetrafluoroethylene material, and a perfluorocarboxylic acid / sulfonic acid composite ionic membrane serves as a cation exchange membrane; and constant-current electrolysis is carried out on the electrolyte in the electrolytic cell. The electrolytic cell hasrelatively high current efficiency and relatively high product purity, and can fully meet the requirements of cleaning and corrosion in the field of electronic industry.