34 results about "Trichloroethane" patented technology

The invention provides chlorotrifluoroethylene continuously prepared based on a microchannel reactor and a preparation method of the chlorotrifluoroethylene, and the chlorotrifluoroethylene comprises the following raw materials in parts by weight: 1, 1, 2-trifluoro-1, 2, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3 The low-temperature refrigerant refrigerant is prepared from the following components in parts by weight: 90 to 100 parts of 1, 2-trichloroethane, 1 to 5 parts of a zinc fluoride induced palladium-copper bimetallic catalyst, 8 to 15 parts of a cyclohexyl dimethyl ether-formic acid composite hydrogen donor, 0.5 to 2 parts of trifluoroacetic anhydride, 0.1 to 0.5 part of a perfluoropolyether lubricant, a proper amount of a low-temperature mixed refrigerant and 15 to 20 percent by weight of diluted hydrochloric acid. According to the invention, the preparation efficiency and product purity of chlorotrifluoroethylene can be improved, and stable operation of the preparation system and reasonable treatment of byproducts can be guaranteed.

The invention discloses a resource utilization method of 1, 1, 2-trichloroethane waste liquid, which comprises the following steps: 1) feeding the 1, 1, 2-trichloroethane waste liquid into a scraper device to remove heavy components, and extracting gas-phase light components from the top; (2) condensing the gas-phase light component, feeding into a chlorination reactor, and carrying out chlorination reaction; and 3) carrying out reactive distillation on the material at the outlet of the chlorination reactor to remove light components and heavy components to obtain 1, 1, 2-trichloroethane. According to the method, on one hand, impurities which influence the purity of 1, 1, 2-trichloroethane and are difficult to separate react with chlorine under specific conditions to generate heavier components, and on the other hand, it is ensured that light components cannot be chlorinated into the impurities which are difficult to separate, and 1, 1, 2-trichloroethane with the purity being 99% or above can be recycled; on the other hand, 5-20 wt% of 1, 1, 2-trichloroethane is additionally generated in the reactive distillation process, waste liquid recycling is achieved, and the method has the advantages of being simple in technological process, low in energy consumption and high in product yield.

The application discloses a preparation method and application of a catalyst for cracking 1,2-dichloroethane to produce vinyl chloride, and comprises the following steps: 1) a neodymium ore is leached with hydrochloric acid, and after filtering a leaching solution, potassium chloride is added to form a doped precursor K2[NdCl3]; 2) an active metal oxide is dissolved in hydrochloric acid, and then added into the doped precursor K2[NdCl3] solution, and co-precipitation is carried out by adding alkali to obtain an emulsion of a doped active component; the active metal oxide is at least one of oxides of vanadium, manganese, titanium and scandium; 3) the emulsion of the doped active component is mixed with a liquid carrier to obtain the catalyst; the liquid carrier is one or more of chloroform, carbon tetrachloride, 1,1,2-trichloroethane and chlorobenzene.

A method for separating R22 and HFP, the method comprising: a mixing step for obtaining a mixture for extraction, the mixture being a mixture of a first mixture containing R22 and HFP and an extraction solvent containing an organic solvent selected from the group consisting of dichloromethane, chloroform, 1, 1, 1-trichloroethane, 1, 1, 2-trichloroethane, 1, 1, 1, 2-tetrachloroethane, 1, 1, 2, 3, 3-tetrachloroethane, 1, 1, 2, 3-tetrachloroethane, 1, 1, 2, 3, 3-tetrachloroethane, 1, 1, 2, 3, 3-tetrachloroethane, 1, 1, 2, 3-tetrachloroethane, 1, 1, 2, 3, 3-tetrachloroethane, 1, 1, 2, 3-tetrachloroethane, 1, 1, at least one chlorine-containing compound selected from the group consisting of 1, 1, 1, 2-tetrachloroethane, pentachloroethane, hexachloroethane, trichloroethylene and tetrachloroethylene; and an extraction distillation step in which the mixture for extraction is distilled to obtain a first distillate having HFP as the main component and a first bottoms product having the extraction solvent as the main component and containing R22, respectively, and an extraction distillation step in which the mixture for extraction is distilled to obtain a first distillate having HFP as the main component and a first bottoms product having R22 as the main component.

An object of the present invention is to provide a novel azeoropic or azeotrope-like composition that is effective for the separation of HF from 1,1,2-trichloroethane (HCC-140), trans-1,2-dichloroethylene (HCO-1130(E)), or cis-1,2-dichloroethylene (HCO-1130(Z)). The object can be achieved by an azeotropic or azeotrope-like composition comprising HCC-140, HCO-1130(E), or HCO-1130(Z), and hydrogen fluoride.

The invention discloses a novel refrigerant and a preparation method thereof, and an underground phase change temperature adjusting device, method and equipment, and relates to the technical field of underground operation, the novel refrigerant containing trichloroethane and dichloropropane provided by the invention is in a liquid state at normal temperature and normal pressure, the boiling point temperature can be about 70-110 DEG C according to different component contents at the normal pressure, and the temperature of the refrigerant can be about 70-110 DEG C according to different component contents. The critical temperature of the novel refrigerant can reach about 130-300 DEG C according to different component contents under pressurization, so that the novel refrigerant provided by the invention can be subjected to phase change in a high-temperature environment, the novel refrigerant can be applied to underground phase change temperature adjusting devices and equipment for high-temperature operation, heat can be absorbed by utilizing heat absorption phase change to realize cooling, and the service life of the novel refrigerant is prolonged. The heat release phase change can release heat to achieve temperature rise, so that heat transfer and temperature control are achieved, the temperature control device can be suitable for controlling the temperature of the working environment of underground instruments and equipment, and the instruments and equipment can normally, stably and reliably work underground.

The invention belongs to the technical field of soil remediation, and particularly relates to a remediation material for degrading polluted soil chlorinated hydrocarbon and a preparation method of the remediation material. The repair material for degrading the chlorinated hydrocarbon in the polluted soil is prepared from the following raw materials: humic acid, rhamnolipid, a biological agent and diatomite. The final repairing material utilizes mutual complementation and mutual synergism of humic acid, rhamnolipid, the biological agent and diatomite, has a remarkable effect in the aspect of degrading trichloroethylene, cis-1, 2-dichloroethylene, trichloroethane and 1, 2-dichloroethane, can be used for repairing chlorohydrocarbon polluted soil, and achieves a better degradation effect.

The invention discloses a non-metal pipeline with heat preservation performance and a manufacturing method thereof. The non-metal pipeline comprises a non-metal pipe body, a heat preservation layer and a polyethylene outer protection pipe, wherein the non-metal pipe body is sequentially and coaxially sleeved with the heat preservation layer and the polyethylene outer protection pipe. The non-metal pipe body is further sleeved with a plurality of supports, and the other free ends of the supports abut against the polyethylene outer protection pipe. The thermal insulation layer is prepared by foaming and curing a thermal insulation material; the thermal insulation material comprises a component A and a component B, the component A comprises the following components in percentage by mass: 1%-5% of ethylenediamine polyether, 0.5%-2.5% of triethanolamine trifluorotrichloroethane silicone oil, 5%-10% of B-trichloroethyl phosphate and the balance of I type fire-retardant polyether; the component B is prepared from polyphenyl polyisocyanate; the mass ratio of the component A to the component B is 1: (1-1.05). The non-metal pipeline has a good heat preservation effect.

The invention relates to a microbial agent for degrading trichloroethane as well as an enrichment method and application of the microbial agent, and belongs to the technical field of microbial engineering. The invention provides a microbial agent for degrading trichloroethane, which comprises a functional bacterium A and a functional bacterium B. The functional bacterium A and the functional bacterium B have amino acid sequences for coding dehalogenase a and / or dehalogenase b, the amino acid sequence for coding dehalogenase a is shown as SEQ ID NO.3, and the amino acid sequence for coding dehalogenase b is shown as SEQ ID NO.4. The invention further provides a preparation method of the microbial agent for degrading trichloroethane. Experiments find that 1, 1, 2-TCA can be degraded into 1, 2-DCA by the dehalogenase a under the condition that the dehalogenase a and the dehalogenase b exist at the same time, and then the 1, 2-DCA is instantly converted into ethylene by the dehalogenase, so that only a small amount or no toxic intermediate product 1, 2-DCA or VC is generated in the degradation process.

The invention belongs to the technical field of synthesis and preparation of organic polymer optical materials, and particularly relates to a cyclotrisulfide-tri (2-mercaptoethyl) thiol composition and a preparation method thereof. The preparation method comprises the following three steps: step 1, performing cyclization and vulcanization reaction on S8 and trichloroethane under the catalysis of aluminum chloride to generate 1, 3, 5-trichlorocyclotrisulfide; step 2, carrying out vinylation reaction on the 1, 3, 5-trichlorocyclotrisulfide and a vinyl magnesium bromide Grignard reagent to generate 1, 3, 5-trivinyl cyclotrisulfide; and 3, carrying out a photocatalytic addition reaction on the 1, 3, 5-trivinyl cyclotripolysulfide and 1, 2-ethanedithiol, and finally synthesizing the cyclotripolysulfide-tri (2-mercaptoethyl) thiol composition. The cyclotripolysulfide-tri (2-mercaptoethyl) mercaptan composition disclosed by the invention is high in transmittance and large in refractive index, and can be used for preparing a polythiocarbamate optical material with a high refractive index and high light transmittance.

The invention relates to the field of environmental microbial remediation, in particular to a compound microorganism for degrading organochlorine pollutants and application of the compound microorganism. The compound microorganism is composed of a bacillus subtilis IAE strain (Geobacter lovleyi sp.strain IAE) and a dehalogenation coccus sp. Strain (Dehalococcoides mccaryi strain BAV1), and the compound microorganism is composed of a bacillus subtilis strain (Geobacter lovleyi sp.strain IAE) and a dehalogenation coccus sp. Strain (Dehalococcoides mccaryi strain BAV1); the preservation number of the bacillus subtilis is CGMCC (China General Microbiological Culture Collection Center) No: 1.5298. Aiming at soil and underground water polluted by high-concentration 1, 1, 2-trichloroethane, the compound bacterium completely degrades 1, 1, 2-trichloroethane into non-toxic ethylene through the synergistic effect of a double dechlorination reaction and a hydrogenolysis dechlorination reaction respectively driven by an IAE strain and a BAV1 strain.

The invention provides a preparation method of polymerized polyamine maleimide resin, and belongs to the technical field of high polymer materials. Comprising the following steps: 1) mixing maleic anhydride, a solvent and 1, 1, 2-trichloroethane; 2) mixing the polyphenyl polyamine, the solvent and the 1, 1, 2-trichloroethane; (3) dropwise adding the polyphenyl polyamine solution into the maleic anhydride solution to carry out amidation reaction; (4) adding a catalyst into an amidation reaction system, and heating to carry out cyclization dehydration reaction; 5) when the temperature of the cyclization dehydration reaction reaches 85-95 DEG C, carrying out gradient heating decompression dehydration and solvent reflux operation, and when the reaction material is in a homogeneous phase state, stopping the reaction and cooling; 6) washing and desolventizing the obtained cooled material to obtain the polymeric polyamine maleimide resin.The preparation method provided by the invention not only can reduce the reaction temperature, reduce the energy consumption and effectively reduce the occurrence of side reactions, but also enables the molecular weight distribution of the prepared product to be more concentrated.

The invention provides a process for manufacturing 1-chloro-2,2-difluoroethane (HCFC- 142) from 1,1,2-trichloroethane (HCC-140) and optionally, one or more of E / Z-1,2- dichloroethene (HCO-1130(E / Z)), E / Z-1-fluoro-2-chloroethene (HCFO-1131(E / Z)), and 1- fluoro-1,2-dichloroethane (HCFC-141). The invention also provides to a process for manufacturing a difluoroethyl derivative from HCFC-142 obtained using the process of the invention.

The invention discloses a method for recovering chlorine in trifluorotrichloroethane production, which comprises the following steps of: a, heating, gasifying and separating crude products, namely organic phases such as liquid chlorine, hydrogen fluoride, hydrogen chloride and trifluorotrichloroethane from an acidic material receiving tank, separating out acidic gases such as chlorine, and carrying out alkali washing on the separated trifluorotrichloroethane; b, cooling the separated acid gases such as chlorine and the like, and separating out uncondensed chlorine; c, fully mixing the separated chlorine gas with tetrachloroethylene; and d, feeding the chlorine-absorbed tetrachloroethylene into a fluorination reaction kettle to participate in the reaction. The method can effectively reduce the unit consumption of liquid chlorine and the consumption of liquid caustic soda.

The invention discloses a method for recycling high value-added substances (1, 1, 2-trichloroethane and TCE) from heavy component waste liquid generated in the VCM (vinyl chloride) generation process, which comprises the following steps: 1) carrying out pretreatment such as hydrogenation or chlorination on the heavy component waste liquid to remove impurities difficult to separate from the heavy component waste liquid; 2) removing high-boiling-point impurities difficult to separate, such as tar, coke and the like, in a novel supergravity rotary rectification manner or a manner of combining scraper solid removal with rectification; and 3) further rectifying and purifying the obtained crude product to obtain the product 1, 1, 2-trichloroethane. The method is simple in technological process, high in recovery rate, high in product purity and stable in device operation, impurities difficult to separate are removed and the technological process is simplified through a direct heavy component pretreatment mode, high-added-value utilization of waste materials can be achieved, economic benefits are generated, energy consumption and carbon emission of the device are reduced, and the method is a novel VCM heavy component recycling technology worthy of popularization.

The utility model belongs to the technical field of chemical production equipment, and relates to a fluorination reaction device for trichlorotrifluoroethane. The fluorination reaction device comprises a reactive distillation tower and a fluorination reaction kettle, the fluorination reaction kettle is connected with a hydrogen fluoride feeding pipe and a chlorine feeding pipe, a discharging pipeline is arranged between the fluorination reaction kettle and the reactive distillation tower, a backflow pipeline is arranged between the reactive distillation tower and the fluorination reaction kettle, the reactive distillation tower is further provided with a tetrachloroethylene feeding pipe, and the tetrachloroethylene feeding pipe is connected with a chlorine feeding pipe. And the joint of the discharge pipeline and the reactive distillation tower and the joint of the return pipeline and the reactive distillation tower are positioned below the tetrachloroethylene feed pipe. In the reaction process, a tetrachloroethylene raw material is conveyed into the reaction rectifying tower through the tetrachloroethylene feeding pipe and is in contact with high-temperature crude gas from the bottom of the reaction rectifying tower, and the tetrachloroethylene absorbs unreacted chlorine in the crude gas and returns the unreacted chlorine to the fluorination reaction kettle, so that the utilization rate of chlorine is increased, and the production cost is reduced. The chlorine content in the trifluorotrichloroethane crude product is reduced, and the consumption of alkali in subsequent alkali washing is reduced.

The invention provides a novel sucralose residue purification method, and belongs to the technical field of purification and impurity removal. The novel sucralose sugar residue purification method comprises the following steps: (1) removing ethyl acetate in mother liquor sugar residues, then carrying out reduced pressure distillation, and then cooling to obtain treated sugar residues; (2) adding thionyl chloride into the candy pomace obtained in the step (1), and converting unstable sucralose dichloro ester in the candy pomace into stable sucralose trichloro ester; and (3) adding trichloroethane into the sucralose trichloro ester to extract and remove impurities, and extracting and removing the trichloroethane at the lower part to obtain a finished product at the upper layer. By adopting the method provided by the invention, the recovery rate of sucralose can be improved, the production cost is reduced, the yield of a finished product is about 85-89%, and the purity is 96-98%; in the implementation process, the production process is optimized, waste liquid discharge is reduced, and environmental friendliness and scientificity are achieved.

The invention belongs to the technical field of non-destructive inspection, and discloses a fuel oil non-destructive inspection agent and a preparation method thereof, the fuel oil non-destructive inspection agent material comprises an activation adsorbent, a dispersant, a surfactant and a propellant; the ratio of the activated adsorbent to the dispersing agent to the surfactant to the propellant is 58: 240: 2: 200. The activation adsorbent is talcum powder; the surfactant is DuPont FSN-100 (Fractional Sensitive Number) The dispersing agent is a mixed solution of mineral oil, trichloroethane, nitromethane and acetonitrile according to a mixing ratio of 30: 60: 5: 5; the propellant is tetrafluoroethane, and the addition amount is 200g. The fuel oil nondestructive flaw detection agent provided by the invention is simple in use process, only the surface needs to be wiped dry with cloth, the flaw detection agent is directly applied, and leakage detection is completed in one step by only using the flaw detection agent; the flaw detection agent is simple and convenient to operate, is directly shown, is non-flammable, has excellent comprehensive performance, can quickly and sensitively detect tiny leakage, does not cause any damage to a unit by using the flaw detection agent, and does not need equipment such as a power supply and a black light lamp.

The application discloses a room-temperature quick-drying type lubricating wear-resistant corrosion-resistant function integrated coating, a coating and a preparation method. The function integrated coating comprises the following raw materials in mass fractions: 8-14 parts of mixed resin; 7-13 parts of lubricating filler; 0.5-1.5 parts of reinforcing filler; and 70-80 parts of dispersion medium. The mixed resin is a combination of polyether sulfone resin, polyvinyl butyral resin, polyurethane resin and alkyd resin, or a combination of polyether sulfone resin, acrylic resin and polyurethane resin; the lubricating filler is a combination of polytetrafluoroethylene and molybdenum disulfide; the reinforcing filler is a combination of nano lanthanum trifluoride and nano cerium oxide; and the dispersion medium is a mixture of trichloromethane and trichloroethane. The coating has the functions of lubrication, wear resistance, corrosion resistance, weather resistance, mold resistance and the like, the salt mist resistance is improved to 240 hours or more, and the wear life is greater than or equal to 60 minutes and the friction coefficient is less than or equal to 0.15 under the conditions of high load and high speed.

The present invention is directed to systems and methods for removing trichloroethane (TCA), trichloroethene (TCE), and 1,4-dioxane (1,4-D) from contaminated water and wastewater. The system and methods relying on catalyst reduction of TCA and TCE, and the reduced products are degraded by microorganisms that are capable of biodegrading ethane and 1,4-D. In certain embodiments, a catalyst film comprises precious nanoparticles with diameters of 5-40 nm and a biofilm comprising microorganisms that are capable of degrading ethane and 1,4-D are used in a dual-reactor system to remove TCA, TCE, and 1,4-D from contaminated water and wastewater.

This invention significantly reduces the impurity content in the resulting concentrated solution by first recovering trichloroethane and then DMF, thereby improving the yield and purity of the crude sucralose-6-ester. Furthermore, this invention utilizes weakly alkaline ammonia to adjust the pH of the system to 6-9, preventing excessive alkalinity from causing the alkaline hydrolysis of sucralose-6-ester to produce sucralose, thus further improving the yield and purity of the crude sucralose-6-ester. Moreover, this invention eliminates the need for large amounts of acid, hydrogen peroxide, organic solvents (in the oxidation reaction stage), and heat energy (in multiple thermal extractions), resulting in low treatment costs for the chlorination neutralization solution. In addition, the treatment method provided by this invention can improve the conversion rate and daily production capacity of sucralose-6-ester in the chlorination neutralization solution, reduce the generation of wastewater and waste activated carbon, resulting in less waste, lower energy consumption, and lower production costs.

A method for separating R22 and HFP includes a mixing step of obtaining a mixture for extraction which is a mixture of a first mixture including R22 and HFP and an extraction solvent including at least one chlorine-containing compound selected from the group consisting of methylene chloride, chloroform, 1,1,1-trichloroethane, 1,1,2-trichloroethane, 1,1,1,2-tetrachloroethane, 1,1,2,2-tetrachloroethane, pentachloroethane, hexachloroethane, trichloroethylene, and tetrachloroethylene, and an extraction distillation step of distilling the mixture for extraction to respectively obtain a first distillate including HFP as a main component, and a first bottom product including the extraction solvent as a main component and including R22.

The application discloses a chlorination process of sucrose-6-acetate, which comprises the following steps: preparing a Vilsmeier reagent by using DMF and chlorosulfuric acid under low-temperature conditions, releasing sulfur dioxide by heating, mixing the Vilsmeier reagent with 1,1,2-trichloroethane as a reaction raw material liquid, mixing the reaction raw material liquid with a pre-cooled DMF solution of sucrose-6-acetate through a pipeline mixer, performing high-temperature chlorination reaction and removing hydrogen chloride by using a three-stage continuous reactor, and sequentially neutralizing the chlorination liquid by using ammonia water and sulfuric acid, so that the target product can be obtained by controlling pH=7-7.5. The process flow is simple, the continuous process of low-temperature mixing, high-temperature reaction and neutralization reaction is realized, the complicated process of separating hydrogen chloride and sulfur dioxide can be omitted, the product yield is improved, the number of production equipment is reduced, the production cost is lowered, and the process has good industrial application value.

This invention relates to the field of environmental bioremediation, specifically to a novel strain of *Desulfovibrio* Co. and its application in reducing sulfate-oxidizing sulfides and degrading and converting 1,1,1-trichloroethane. The *Desulfovibrio* Co. strain was deposited on February 24, 2024, at the China General Microbiological Culture Collection Center (CGMCC), located at No. 3, Courtyard 1, Beichen West Road, Chaoyang District, Beijing, Institute of Microbiology, Chinese Academy of Sciences, 100101, China, accession number CGMCCNo. 41182.

The invention discloses a hydrogen-assisted dechlorination catalyst and a preparation method thereof. The catalyst is prepared from an active component, a metal additive and a carrier, the metal additive is supported on the carrier through an isovolumetric wet impregnation method, and the active component is anchored to the surface of the metal additive through a redox deposition method; the active component is selected from at least one of noble metals Pt, Pd, Rh, Ru and Au according to the mass percentage of the total amount of the catalyst, and the mass fraction of the active component is 0.2-2.0%; the metal additive is selected from at least one of Ag, Cu, Ni, Co, Fe and K, and the mass fraction of the metal additive is 2.0%-10.0%. By adjusting the types and relative proportions of the active components and the metal additives, the catalytic activity of the catalyst in the hydrodechlorination process of 1, 1, 2-trifluorotrichloroethane, the selectivity of trifluorochloroethylene and the service life of the catalyst are improved.

The invention provides a preparation method of a catalyst for 1, 1, 1, 4, 4, 4-hexafluoro-2, 3-dichloro-2-butene as well as the catalyst and application of the catalyst. Activated carbon is immersed in a transition metal halide salt aqueous solution, and activated carbon loaded with transition metal halide salt is obtained through adsorption; and activating the active carbon loaded with the transition metal halide salt in a reducing atmosphere to obtain the carbon-loaded transition metal simple substance catalyst. The carbon-supported transition metal simple substance catalyst has an efficient catalytic coupling effect on 1, 1, 1-trifluorotrichloroethane, so that 1, 1, 1, 4, 4, 4-hexafluoro-2, 3-dichloro-2-butene is prepared, and the carbon-supported transition metal simple substance catalyst can be used for producing downstream products such as 1, 1, 1, 4, 4, 4-hexafluoro-2-butene and hexafluoro-2-butyne which are urgently needed. Effective recycling of waste resources is achieved, the urgent requirement of the market for environment-friendly fluorinated products is met, and remarkable environment-friendly and economic benefits are achieved.

The invention belongs to the technical field of chemical equipment, and discloses a trifluorotrichloroethane deacidification device, including a circulation tower, an acidic material receiving tank, a cryogenic condenser, a stratification tank, a material cooler, a deacidification tower kettle, a deacidification tower, a deacidification tower condenser, a deacidification tower feed pump, a material water washing tower, a material alkali washing tower, a water cooler, an alkali washing circulation pump, an alkali washing circulation tank, and a water separator; the cryogenic condenser is connected to the circulation tower, the circulation tower, the stratification tank and the acidic material receiving tank are connected through a gas phase balance pipe, the circulation tower and the stratification tank are connected, and the lower part of the stratification tank is connected to the acidic material receiving tank; the deacidification tower kettle is connected to the acidic material receiving tank, the lower part of the material water washing tower is connected to the upper part of the material alkali washing tower, the lower part of the material alkali washing tower is connected to the upper part of the water separator, and the upper part of the material alkali washing tower is connected to the alkali washing circulation tank. The present invention is applied to the trifluorotrichloroethane deacidification system, the water washing and alkali washing systems are easy to operate, the acidic material content of the product trifluorotrichloroethane is reduced, and the product quality is improved.

The application relates to the field of organic synthesis, in particular to a preparation method of trichlorotrifluoroethane and trifluoroacetic acid, which comprises the following steps: adding trichloroethylene, a catalyst and anhydrous hydrogen fluoride into a pressure kettle, stirring, slowly heating and performing a fluorination reaction, stopping the fluorination reaction, not releasing the hydrogen chloride gas generated in the reaction process, and cooling to-33 DEG C to 0 DEG C; introducing chlorine gas into the reaction kettle, closing the valve of the pressure kettle, slowly heating and reacting, controlling the temperature in the kettle at 30-40 DEG C after the reaction is completed, slowly releasing the gas in the kettle into alkali water absorption, finally discharging the remaining liquid from the bottom valve of the kettle, and adding the liquid into the alkali water for quenching; adding water, standing and separating, and taking the lower oily substance as a trichlorotrifluoroethane crude product; and performing rectification to obtain a finished product. The application can avoid separation and purification of a low-boiling-point fluorination intermediate 1,1,1-trifluoro-2-chloroethane, avoid loss of the intermediate in a post-treatment operation process, and simplify the operation.

The invention provides a method for preparing trans-1, 2-dichloroethylene through dehydrochlorination of 1, 1, 2-trichloroethane, and belongs to the technical field of chlorinated olefin preparation. The preparation method provided by the invention comprises the following steps: mixing 1, 1, 2-trichloroethane with protective gas to a certain concentration, and carrying out HCl removal reaction under the action of a catalyst to generate trans-1, 2-dichloroethylene. According to the method for preparing trans-1, 2-dichloroethylene by removing HCl from 1, 1, 2-trichloroethane, provided by the invention, the raw materials are wide in source and cheap, the reaction is simple, and the operation is safe. By optimizing the surface properties and reaction conditions of the niobium oxyphosphate catalyst, the selectivity of t-DCE exceeds 40%, the yield of the target product is remarkably improved, and the requirements of industrial production for high-selectivity products are met.

The present invention relates to a method for assaying the quantity of hydroxyl functions present in a polyol, the method comprising the following steps: (i) acetylating the hydroxyl functions of the polyol into ester functions by reacting the polyol with acetic anhydride in excess; (ii) hydrolyzing the mixture of acetylated polyol, acetic anhydride and acetic acid obtained at the end of step (i); and (iii) assaying by potentiometry the acetic acid obtained at the end of step (ii), the acetylation step (i) being carried out in the presence of at least one 4-dialkylaminopyridine catalyst of formula (1) or one of the salts thereof: wherein R and R', which are identical or different, are C1-C6 alkyl groups, or R and R' together form a C2-C6 ring, in the presence of at least one solvent selected from toluene, and in the presence of at least one cosolvent selected from xylene, anisole, benzene, chlorobenzene, bromobenzene, cyclohexane, octane, heptane, dichloromethane, dichloroethane, trichloroethane, carbon tetrachloride, trichloroethylene, chloroform, acetonitrile, dimethylformamide, dimethylacetamide, ethyl acetate, acetone, pyridine.