175 results about "Crystallization Purification" patented technology

The invention belongs to the field of electronic chemical purification, and particularly relates to a method for strengthening a phosphoric acid melt crystallization process through ultrasound and residual liquid circulation, which comprises the following steps: adding a high-concentration phosphoric acid raw material into a static melt crystallizer, cooling and graining, and enhancing the purity by adopting ultrasound in a sweating stage, high-concentration uncrystallized raffinate is cooled by an external circulation coil heat exchanger and then flows back to a crystallizer, crystallization continues to be carried out, the yield is increased, and the Fe content can be reduced to 20 ppb from 73 through crystallization purification. The concentration of phosphoric acid adopted by the method is greater than or equal to 85%, the problems of poor impurity removal effect, low yield and long consumed time of a conventional static crystallization method are solved, the uncrystallized residual liquid is fully recycled, the energy consumption is reduced, and the method has high applicability.

A multistage melt crystallization purification method for BHT (butylated hydroxytoluene) adopts a two-stage melt crystallization process and comprises the following steps: firstly, melting a crude product BHT, and then separating mother liquor M1 through first-stage crystallization (cooling to 60-65 DEG C at a speed of 0.5-2 DEG C / h); and then, carrying out secondary melting on the primary crystal, carrying out secondary crystallization (cooling to 65-68 DEG C at the speed of 0.1-0.5 DEG C / h) and separating mother liquor M2, carrying out gradient heating (0.1-0.5 DEG C / 20min) to 68-70 DEG C, sweating and discharging sweat M3, and finally, melting to obtain BHT liquid with the purity of more than or equal to 99.9%. And recycling the mother liquor M1 to a synthesis rectification process, and respectively returning the mother liquor M2 and the mother liquor M3 to the primary crystallizer and the secondary crystallizer for cyclic utilization. According to the method, a solvent is not needed, the yield is remarkably improved through mother liquor recycling, high-temperature decomposition is avoided, the product purity is high, the stability is good, the sliced finished product is not prone to discoloring, the technological process is energy-saving and efficient, and the method is suitable for industrial production of medicine and food-grade BHT.

The embodiment of the invention provides a method for separating a benzenediol isomer and 5-indanol in a phenol-containing crude product, which comprises the following steps: rectifying the phenol-containing crude product to obtain mixed benzenediol with a distillation range of 240-300 DEG C; the method comprises the following steps: carrying out etherification reaction on mixed benzenediol with the distillation range of 240-300 DEG C obtained by rectifying crude phenol rectification residues by adopting etherification reaction: carrying out etherification reaction on the mixed benzenediol and an etherification reagent under the action of a catalyst, recovering excessive etherification reagent in a reactant after the reaction, and rectifying to obtain etherate; wherein hydroquinone dialkyl ether with the purity not lower than 98% is crystallized and purified by adopting a melt crystallization method or a solvent crystallization method; and / or reducing a part of etherate by using mixed trimethylbenzene and hydrobromic acid to obtain various benzenediol isomers and 5-indanol.

The invention relates to the technical field of crystallization and purification, in particular to a glucolactone crystallization method. The method comprises the following steps: sequentially carrying out four-stage cooling crystallization on a raw material containing gluconic acid, wherein each stage of cooling crystallization comprises gradient cooling independently carried out in four temperature zones. According to the method provided by the invention, glucolactone crystals with regular and uniform particles, narrow particle size distribution range and high purity can be obtained, the yield is obviously higher than that of a conventional one-time crystallization method, especially when centrifugal separation is carried out, the separation effect is good, the water content of the separated material is low, the addition of crystal washing water in the separation process is less, and the mother liquor generation amount is less; and the production cost is greatly reduced.

The invention discloses a method for purifying p-dioxanone by coupling vacuum distillation with melt crystallization, which comprises the following steps: removing light and heavy impurity components contained in a crude product of p-dioxanone by vacuum distillation, and carrying out melt crystallization, sweating and filtering on the p-dioxanone subjected to vacuum distillation purification to obtain the p-dioxanone. High-purity p-dioxanone is obtained, and uncrystallized mother liquor is returned to the step of vacuum rectification.

The invention discloses a method for simultaneously preparing a filter aid and aluminum salt from lithium slag, and relates to the technical field of waste resource utilization. The method comprises the steps that the lithium slag is pretreated to remove substances with magnetism and / or large specific gravity in the lithium slag, and pretreated slag is obtained; uniformly mixing a mixed solution of ammonium sulfate and sulfuric acid with the pretreatment slag, grinding, carrying out hydrothermal reaction on the mixed slurry, and carrying out solid-liquid separation to obtain silicon slag and an aluminum ammonium sulfate solution; carrying out microwave treatment on the silicon slag to obtain a filter aid; and carrying out cooling crystallization and recrystallization purification on the aluminum ammonium sulfate solution to prepare aluminum ammonium sulfate. According to the method, the spodumene lithium extraction tailings are used as the raw material, valuable components in the lithium slag can be efficiently utilized in an environment-friendly mode, the filter aid and the aluminum salt which are excellent in performance are prepared, cyclic utilization of resources is achieved, and the method has important practical significance and wide application prospects. In addition, valuable metal elements such as rubidium, cesium, titanium and beryllium can be comprehensively recycled, and the resource utilization rate is increased.

The invention discloses a method for producing high-purity cesium phosphate by using mother liquor after lithium extraction, which comprises the following steps: by using waste liquor generated after lithium extraction of lepidolite as a raw material, adding auxiliary materials such as an acidifying reagent, an aluminum precipitation and sulfur radical removal reagent and the like; the high-purity cesium phosphate is produced through the procedures of sodium and potassium mixed salt precipitation, acidification alum precipitation, recrystallization purification, aluminum precipitation sulfur radical removal, concentration crystallization, centrifugal drying and the like, the product purity reaches 99.9% or above, and the method is wide in raw material source, high in energy utilization rate, simple and feasible in process, small in equipment investment, low in cost, short in production period, high in efficiency, free of new waste, environmentally friendly and suitable for industrial production. The comprehensive recycling of the lithium precipitation mother liquor is effectively realized, the economic value of the lepidolite is improved, the production cost of extracting lithium from ore is reduced, the cesium source is saved, the pollution problem of waste liquid is also reduced, and the method can be comprehensively popularized and applied to the industrial production of extracting lithium from the lepidolite.

The invention relates to the field of chemical synthesis, and provides a preparation method of tris (2, 4-di-tert-butylphenyl) phosphite, which comprises the following steps: (1) dispersing 2, 4-di-tert-butylphenol and a catalyst in a solvent I, heating to 30-50 DEG C, and adding phosphorus trichloride for vacuum reaction; the catalyst is tetramethyl guanidine acid radical ionic liquid; (2) heating to 100-140 DEG C, and reacting to obtain a crude product; or heating to 100-140 DEG C, reacting to obtain a crude product, crystallizing and purifying the crude product to obtain a pure product and crystallization mother liquor, and recovering the catalyst from the crystallization mother liquor. According to the method disclosed by the invention, the tris (2, 4-di-tert-butylphenyl) phosphite ester with high yield and high purity is prepared under mild conditions by taking the tetramethyl guanidine acid radical ionic liquid as a catalyst, and the catalyst is easy to recover and can be used for multiple times.

The invention discloses a high-salinity wastewater resource utilization method and device, belongs to the technical field of chemical engineering, and relates to wastewater treatment. The invention relates to a high-salinity wastewater resource utilization method which comprises the following steps: (1) deep removal of organic matters in a high-salinity system: realizing selective separation and removal of the organic matters in wastewater by using a synergistic effect of a flocculating agent and a catalyst; (2) mixed salt separation and recycling: realizing stable separation of sodium chloride and sodium sulfate through the design of MCR-nanofiltration-reverse osmosis multi-membrane coupling synergistic gradient coupling and reflux nesting; and (3) stable control of evaporative crystallization of a complex system: a scale inhibitor, humic acid and a defoaming agent are used, and fractional crystallization and purification are realized through high-temperature firing. According to the method, recycling circulating water can be saved, a large amount of sodium chloride and sodium sulfate are recycled as byproducts, COD and ammonia nitrogen are reduced, the recycling rate of sodium sulfate and sodium chloride is larger than 85%, and the water recycling rate is larger than 95%.

The utility model relates to the technical field of recrystallization purification, and discloses a recrystallization purification device which comprises a purification pipe, a heating sleeve, an overflow assembly and a cut-off assembly, the heating sleeve is installed on the surface of the purification pipe, the overflow assembly is connected to the surface of the purification pipe, and the cut-off assembly is arranged at the bottom end of the purification pipe. According to the recrystallization purification device, the heating sleeve, the purification pipe, the overflow assembly, the cut-off assembly and the isolation plate are arranged, an object to be purified is added to the isolation plate with fine holes, then deionized water is added on the premise that it is guaranteed that a saturated solution is sufficiently formed at the high temperature, and the water surface is higher than the overflow assembly; impurity precipitates and undissolved purified substances in the solution gradually sink and are enriched to the position of the intercepting assembly, suspended solids are enriched to the liquid level, the suspended solids are discharged by opening the overflow assembly firstly, and then the intercepting assembly is opened to discharge the precipitates, so that impurities can be rapidly discharged, filter paper and filter cloth residues are prevented from being mixed into purified products, and the purification quality is improved.

The application discloses a potassium fluorotantalate crystallization purification method, and relates to the technical field of tantalum hydrometallurgy and fluorotantalate crystallization purification. The method comprises the following steps: filtering a tantalum-containing fluorine acid solution, adding a potassium source and a tantalum-niobium separation type composite crystallization regulator, stirring and complexing, seed induction, controlled cooling crystallization, graded removal of the regulator, solid-liquid separation, and potassium fluoride containing fluorine acid washing to obtain primary purified potassium fluorotantalate crystals, and then redissolving the primary purified potassium fluorotantalate crystals in a fluorine-containing acid solution, correcting the K / Ta molar ratio, repeatedly regulating and crystallizing, graded removal of the regulator, washing, and drying to obtain high-purity potassium fluorotantalate. The regulator can reduce the entrainment of niobium impurities and reduce the residual amount of the regulator itself, thereby improving the purity of the product and the Ta yield.

The invention discloses a low-energy-consumption crystallization purification method of high-purity molten salt-grade potassium nitrate, and belongs to the technical field of purification of inorganic chemical materials. The method comprises the steps of raw material pretreatment directional impurity removal, multi-stage gradient crystallization, mother liquor graded circulation and low-temperature drying, in the raw material pretreatment stage, impurity concentration online detection and dynamic pH regulation are combined, a chelating agent, an oxidizing agent and an adsorption flocculant are added step by step, precise directional removal of metal impurities and suspended solids is achieved, and the product purity is improved; a multi-stage gradient crystallization process combining gradient temperature control and sectional controllable cooling is adopted, and the crystallization efficiency is improved in cooperation with a crystal form regulating agent; a mother liquor graded circulation and drying waste heat recovery system is matched, so that the mother liquor utilization rate is increased, and the production energy consumption is reduced.

The crystallization purification preparation system for 2, 6-dimethylnaphthalene comprises a suspension stirring crystallizer and a crystal filter, the suspension stirring crystallizer is connected to one end of the crystal filter, and the other end of the crystal filter is connected with a residual liquid tank and a static crystallizer; a mother liquid tank and a finished product tank are arranged on the first pipeline between the static crystallizer and the crystal filter; meanwhile, the residual liquid tank, the mother liquid tank and the static crystallizer are also respectively connected with a waste removal and discharge pipeline; wherein the suspension stirring crystallizer is connected with a cooling and heating all-in-one machine through a cooling and heating medium pipeline, and the static crystallizer is also connected with the cooling and heating all-in-one machine through the cooling and heating medium pipeline. According to the method, high-purity 2, 6-dimethylnaphthalene is obtained from low-value petrochemical raw materials by adopting a crystallization purification method.

The invention provides a preparation method for synthesizing lithium sulfide from industrial-grade lithium hydroxide and sodium sulfide, a preparation method for a solid electrolyte and a solid-state battery, and the preparation method for synthesizing lithium sulfide from industrial-grade lithium hydroxide and sodium sulfide comprises the following steps: dissolving an industrial-grade lithium hydroxide raw material, and sequentially carrying out oxidation, filtration, washing and drying to obtain lithium sulfide; sodium sulfide and a flocculating agent are added for precipitation and filtration, then sodium carbonate and barium nitrate are sequentially added for impurity removal and filtration, and a lithium hydroxide purified solution is obtained; reacting the sodium sulfide solid with dilute sulphuric acid to obtain hydrogen sulfide gas; hydrogen sulfide gas is introduced into the lithium hydroxide purification liquid for a reaction, and lithium sulfide slurry is obtained; evaporating, concentrating and crystallizing the lithium sulfide slurry, and centrifugally separating; and carrying out vacuum calcination on the crystal, and crushing to obtain lithium sulfide powder. Through oxidative conversion, chemical precipitation and crystallization purification, efficient and deep removal of impurities is realized, the problems that raw material components are complex and difficult to separate are solved, and the purity of lithium sulfide is improved.

This invention relates to the field of lithium battery technology and discloses a method for purifying lithium hexafluorophosphate by continuous flow crystallization. The method includes: (1) adding a first organic solvent to crude lithium hexafluorophosphate to dissolve it, preparing a saturated lithium hexafluorophosphate-organic solvent solution, filtering to remove insoluble matter, and obtaining a saturated lithium hexafluorophosphate solution; (2) feeding the saturated lithium hexafluorophosphate solution and the second organic solvent into a microchannel reactor for cooling using metering pumps, filtering the precipitated crystals, washing them with a cooled third organic solvent, and then vacuum drying. The lithium hexafluorophosphate precipitated by the method of this invention has high purity and stable quality, making it very suitable for industrial promotion and application.

The present application relates to a kind of preparation methods and systems of electronic grade dimethyl carbonate prepared from dimethyl oxalate, the method comprises the following steps: dimethyl oxalate is preheated and sent into decarboxylation reactor to carry out decarboxylation reaction, carbon monoxide, dimethyl carbonate and other light components are extracted from the top of decarboxylation reactor, and heavy components are extracted from the bottom of decarboxylation reactor;Carbon monoxide, dimethyl carbonate and other light components extracted are separated after gas-liquid, and liquid phase dimethyl carbonate is sent into rectifying column to carry out rectification purification;Electronic grade dimethyl carbonate product is obtained by crystallization purification in refrigeration crystallization device after rectification, and crystallization mother liquor returns rectifying column;Decarboxylation reactor is three-stage reaction tower, and rectifying section, reaction section, stripping section are sequentially from top to bottom.The present application is completely reacted by the design of three-stage decarboxylation reactor;Heavy components generated are extracted in real time, and catalyst stability is high;Electronic grade DMC is prepared by using rectifying column coupled with crystallization tower, and the yield of DMC is significantly improved.

The invention provides a post-treatment method of an acid-containing DNBP crude product. The method comprises the following steps: deacidifying and dehydrating an acid-containing DNBP crude product to obtain a neutral DNBP crude product, mixing the neutral DNBP crude product with a crystallization solvent, and carrying out low-temperature recrystallization refining purification, so that a traditional DNBP crude product post-treatment refining process of washing with water and then distilling is abandoned, the refining process is green and environment-friendly, no wastewater is generated, the low-temperature recrystallization refining process does not need to heat a nitride DNBP, and the yield is high. The crystallization mother liquor obtained by recrystallization is rectified and separated to obtain a reaction solvent and a crystallization solvent for cyclic utilization, and meanwhile, after the crystallization solvent is added into the DNBP byproduct obtained after rectification, the DNBP byproduct can be further subjected to low-temperature crystallization purification. Tests show that the purity of the obtained pure DNBP product is more than or equal to 99%, the free acid content (in terms of H2SO4) is less than or equal to 0.01%, the benzene insoluble substance content is less than or equal to 0.1%, and each index meets the industrial requirements.

The invention provides a device and a method for preparing 2, 6-naphthalic acid. The device comprises an oxidation reactor for carrying out oxidation reaction on acyl naphthalene, a catalyst and air in a solvent, at least two crystallizing tanks for crystallizing and purifying products of the oxidation reaction, and a rectifying tower for carrying out distillation separation on water, the solvent and impurities, the oxidation reactor is a full-backmixing double-sleeve bubbling bed reactor; all the crystallizing tanks are connected with the oxidation reactor, the softened water source and the filter; the rectifying tower is connected with the filter and the oxidation reactor, and the rectifying tower is a continuous efficient filler rectifying tower. According to the device for preparing the 2, 6-naphthalic acid, the full-backmixing double-sleeve bubbling bed reactor is used, the purity and yield of products are ideal, through reasonable system configuration and technological process design, whole-process continuous production can be achieved, and the production efficiency is high.

The invention relates to the field of organic chemical synthesis, and discloses a method for preparing homo-2-methyl-4-chloropropionic acid. Comprising the following steps: reacting chiral 2-chloropropionic acid with a liquid caustic soda solution to generate sodium 2-chloropropionate, reacting p-chloro-o-cresol with liquid caustic soda to generate sodium p-chloro-o-cresol, carrying out nucleophilic substitution reaction to generate a precursor of 2-methyl-4-chloropropionic acid, carrying out acidification reaction to generate 2-methyl-4-chloropropionic acid, cooling, crystallizing, purifying, extracting with a solvent and the like. By controlling reaction conditions, such as temperature, pH value, reaction time and the like, a high-yield and high-purity product is ensured, and the optical loss is less than 1.5%. The method is efficient, environmentally friendly and suitable for large-scale industrial production, and high quality and stability of 2-methyl-4-chloropropionic acid can be guaranteed.

The application provides a purification method and dichloroisocyanurate obtained by using the method. The purification method of dichloroisocyanurate comprises the following steps: repeatedly crystallizing crude dichloroisocyanurate obtained in a production synthesis process to obtain purified dichloroisocyanurate. The purification method of dichloroisocyanurate of the application utilizes the different melting points of dichloroisocyanurate and other impurities, and is designed to be repeatedly crystallized at different gradient temperatures. By adjusting the crystallization temperature and the crystallization time, the impurities in the dichloroisocyanurate can be removed. Compared with the crude distillation method, the obtained dichloroisocyanurate has higher purity, and is safer and easier to operate.

The invention relates to composite ceramic, a preparation method thereof, aluminum segregation purification equipment and an aluminum segregation purification method. The preparation raw materials of the composite ceramic comprise silicon nitride, lithium titanate and silicon carbide. The composite ceramic is high in mechanical property, high in thermal conductivity and good in chemical stability and can be used as a crystallization rod in aluminum segregation and purification equipment for segregation, crystallization and purification of aluminum, and the crystallization rod made of the composite ceramic has longer service life compared with a graphite crystallization rod, so that the replacement frequency of the crystallization rod can be reduced, and the production cost is reduced. And the cost of aluminum segregation extraction is reduced.

The invention discloses an o-methylbenzyl chloride production process and a production system thereof, and relates to the technical field of o-methylbenzyl chloride production, and the process comprises the steps of reaction raw material pretreatment, staged chlorination reaction, in-situ separation and real-time purification, o-methylbenzyl chloride crude product pretreatment, o-methylbenzyl chloride refining treatment, catalyst recovery and environmental protection treatment. The preparation method has the advantages that by improving the uniformity of free radical generation and the good dispersity of the initiator, the free radical generation sites and concentration in the reaction system are more uniform, and the occurrence of local over-reaction areas and incomplete reaction areas is reduced, so that the problems of excessive chlorination and raw material waste are reduced; the temperature, chlorine flow and illumination conditions are accurately controlled in the staged chlorination reaction, so that hydrogen atoms on benzyl carbon atoms are prevented from being continuously substituted, generation of byproducts such as o-methylbenzyl chloride is reduced, the purity of the target product o-methylbenzyl chloride is improved, and the requirement for subsequent multiple distillation or crystallization purification is reduced.

This invention relates to an extraction method for improving the bioavailability of tartrate tylosin. The method includes subjecting tartrate fermentation broth to a single acid-dissolution and alkali-precipitation treatment, followed by static crystallization to obtain crude tartrate. This crude tartrate is then subjected to extraction and back-extraction steps, followed by decolorization and ultrafiltration to obtain refined tartrate. Finally, it is spray-dried to obtain tartrate tylosin. This invention optimizes the extraction process of tartrate tylosin by combining a single acid-dissolution and alkali-precipitation crystallization purification process with extraction and back-extraction processes, effectively improving the bioavailability of tartrate tylosin.

The invention relates to the technical field of purification equipment, in particular to dibenzoyl tartaric acid low-energy-consumption purification equipment which comprises an equipment frame, a freezing crystallizing tank is rotatably connected to the equipment frame, a rotating seat is rotatably connected in the freezing crystallizing tank, and a mounting pipe is fixedly connected to one end of the rotating seat. A mounting pipe is arranged on the equipment frame, a crystal separation net seat is movably inserted into one end of the mounting pipe, an adjusting scraping mechanism is rotatably connected in the freezing crystallizing tank, a liquid discharge pipe is fixedly connected to one end of the freezing crystallizing tank in a penetrating manner, and a solution pre-cooling seat is fixedly arranged on the equipment frame. And automatic separation is carried out in a manner of overturning the freezing crystallization tank and rotating the crystallization separation net seat, so that the complex process of taking out crystal substances is avoided, the freezing environment is kept, the risk of melting the crystal substances is reduced, the separation efficiency is improved, the energy consumption is reduced, and the product purity is improved. The overall efficiency and effect of freezing crystallization purification are greatly improved.

The invention discloses an efficient synthesis method of brexpiprazole, which comprises the following steps: taking 4-bromo-benzothiophene and N-Boc-piperazine as initial raw materials, under the protection of nitrogen, carrying out reaction by using a supported catalyst to prepare 4-Boc piperazine benzothiophene, and then carrying out acidolysis to obtain 4-piperazine benzothiophene hydrochloride; the method comprises the following steps: reacting 3, 4-dihydro-7-hydroxy-2 (1H) quinolinone with 1-bromo-4-chloro-butane to generate 3, 4-dihydro-7-(4-chlorobutoxy)-2 (1H)-quinolinone, and then converting the 3, 4-dihydro-7-(4-chlorobutoxy)-2 (1H)-quinolinone into 7-(4-chlorobutoxy)-2 (1H)-quinolinone; then condensing with 4-piperazine benzothiophene hydrochloride to obtain a crude product of brexpiprazole; and finally, crystallizing and purifying for multiple times to obtain high-purity brexpiprazole. According to the preparation method disclosed by the invention, 4-bromo-benzothiophene and N-Boc-piperazine are taken as starting raw materials, and high-purity brexpiprazole is prepared by optimizing selection of a catalyst and conditions of each step and through an excellent purification process.

The invention discloses a crystallization purification method of a benzoxazine compound and application of the benzoxazine compound, the crystallization purification method comprises the following steps: dissolving a compound I in a crystallization solvent, and then separating out crystals in a volatilization or cooling mode; wherein the compound I has the following chemical structure. The method disclosed by the invention is high in crystallization speed and high in crystallization efficiency, and overcomes the problems of easiness in caking, wall sticking and the like of raw material oily substances; the crystal obtained by the method is high in purity, low in impurity content and easy to obtain, and preparation processing and industrial production are facilitated; the crystal obtained by the method has a more excellent drug effect. # imgabs0 #

The utility model discloses a racemic p-hydroxyphenylglycine recrystallization device, and belongs to the technical field of chemical production devices and crystallization purification. The device comprises a decoloration and impurity removal kettle, a filter, a crystallization kettle, a centrifugal machine and the like, and has the innovation points that 1, a precise microporous membrane filter is additionally arranged in the decoloration and impurity removal process of the DL-hydroxyphenylglycine, and a rubber and plastic cotton heat preservation layer is additionally arranged on the outer surface of the microporous membrane filter; 2, a stirrer of the crystallization kettle is arranged into a double-layer structure, and an upper-layer stirring paddle is arranged into a rake shape; 3, an airflow control valve is additionally arranged between the crystallization kettle and the bottom valve; according to the technical scheme, the DL-p-hydroxyphenylglycine recrystallization device effectively solves the problem that tiny impurity points still exist after mother liquor is filtered, the problem that a pipeline is blocked due to temperature reduction in the midway of filtering, and the problem that a discharge valve of a crystallization kettle is easy to block; the device also has the characteristics of high production efficiency, high product purity and convenience in operation.

The invention relates to a melt crystallization purification method of beta-methylnaphthalene, and relates to the field of beta-methylnaphthalene purification, and the melt crystallization purification method comprises the following steps: sequentially carrying out first cooling crystallization, second cooling crystallization, third cooling crystallization, sweating operation, melting, recrystallization and devitrification on molten beta-methylnaphthalene to obtain beta-methylnaphthalene with the purity of more than or equal to 99.8%, wherein the second cooling crystallization is assisted by first microbubble treatment. According to the method provided by the invention, by virtue of a specific cooling crystallization process, the uniformity of crystal growth is ensured, the risk that a crystal layer is too thin or too thick in the prior art is avoided, the separation efficiency of the crystal is improved, efficient separation and extraction of high-purity beta-methylnaphthalene are realized, and the purity of the obtained beta-methylnaphthalene is greater than or equal to 99.8%.

The invention discloses a high-purity synthesis method of 18-crown ether-6, which is characterized by comprising the following steps: S1, in an industrial microwave reactor provided with a special nano-material lining, uniformly mixing p-toluene sulfonic acid dihydric alcohol ester, dihydric alcohol, an alkaline substance and a composite solvent, and reacting at 0-40 DEG C for 0.2-5 hours to obtain a reaction product; in the reaction process, the reaction is promoted by virtue of the special property of the nano-material lining; and S2, after the reaction is finished, obtaining a high-purity target product 18-crown ether-6 through a specific post-treatment process. According to the method, the industrial microwave reactor provided with the special nano-material lining is adopted for reaction, the classical Williamson etherification reaction is accelerated through microwaves, the reaction time is greatly shortened, the reaction speed is greatly increased compared with that of a conventional method, meanwhile, the special purifying agent acetonitrile is added for crystallization purification, the purity of the product can be effectively improved, and the method is suitable for industrial production. The purity of the 18-crown ether-6 is not lower than 99.5%.

The invention discloses a method for preparing high-purity 2-methyl-6-acylnaphthalene and 2-methyl-7-acylnaphthalene through continuous catalytic reaction and rectification purification and application of the high-purity 2-methyl-6-acylnaphthalene and the 2-methyl-7-acylnaphthalene. According to the method, high-purity 2, 6-and 2, 7-acyl naphthalene products can be obtained through fixed bed catalytic synthesis, rectification and crystallization purification, firstly, the molecular sieve catalyst is modified, the catalytic conversion rate and selectivity can be further improved, the formed catalyst is suitable for fixed bed acylation synthesis reaction, the catalyst activity in a catalytic system is high, and the catalytic efficiency is high. The used catalyst can be reused after regeneration treatment. The fixed bed catalytic reaction system, the product and the catalyst can realize solid-liquid separation without hydrolysis quenching, a large amount of acidic wastewater is not generated, the fixed bed catalytic reaction system is environment-friendly, in addition, unreacted 2-methylnaphthalene in a rectification system is recycled, a target object can be purified through rectification and crystallization, a high-purity product is obtained, and the fixed bed catalytic reaction system has a good application prospect.