32results about How to "Reduce the number of crystallization" patented technology

The invention provides a synthesis process of acipimox, which comprises: 1) in an aqueous solution, under the action of a catalyst, reacting 5-methylpyrazine-2-carboxylic acid with hydrogen peroxide; Step 1) Add an auxiliary agent to the solution obtained, wherein the auxiliary agent is selected from one of sulfite, bisulfite, oxalic acid and oxalate; 3) Add to the solution obtained in step 2) Activated carbon, filter; and 4) The solution obtained in step 3) is cooled to crystallize and dried to obtain the finished product of acipimox. The synthesis process of the invention can effectively reduce the number of crystallization times, avoid recrystallization operation, improve yield and reduce production cost.

The invention discloses a preparation method of ivermectin, comprising the following steps: 1) preparing crude ivermectin; 2) dissolving the crude ivermectin in a solvent, heating and stirring until completely dissolved, and keeping warm; 3) ) adding purified water and formamide to the crude product solution and controlling the flow rate, cooling down to obtain a diluted solution; 4) adding seed crystals to the diluted solution to grow crystals; 5) cooling and crystallizing the diluted solution to a certain temperature; 6) High-purity ivermectin fine powder can be obtained through suction filtration, washing and drying. The yield of the preparation method of the present invention reaches more than 85%. The present invention provides a preparation process with simple process, stable yield and large-scale production of high-purity ivermectin.

The purpose of the present invention is to disclose a camptothecin separation and purification method, particularly a technology for preparing high-purity camptothecin by using diatomaceous earth filtration, membrane separation technology, macroporous adsorption resin column chromatography adsorption and chromatography column preparation integration purification. With the method of the present invention, the problems that the selectivity of extraction and adsorption on the target compound is low, the purity of the prepared camptothecin is not high, and the multiple extraction-recrystallization way has disadvantages of high organic solvent consumption, labor consuming, time consuming, poor economy, high industrial production and serious environmental pollution are solved.

The invention discloses a method for separating cholesterol and 24-dehydrocholesterol by complex crystallization. First, soluble cuprous salt is used as a complexing agent to obtain high-purity cholesterol through complex crystallization, and then cholesterol and 24-dehydrocholesterol in the mother liquor are separated by toluene. The dehydrocholesterol was extracted, and the mixture obtained after evaporating to dryness was dissolved in acetic acid for recrystallization to obtain high-purity 24-dehydrocholesterol. Simultaneously, after the mother liquor of acetic acid is evaporated, its dried matter can be used as raw material continuously, thereby improving the whole process yield. The present invention can be separated by using a crystallization reactor commonly used in the field, has low requirements on equipment, and the complexing agent used can greatly improve the separation efficiency, and has the characteristics of simple operation, less solvent consumption, and environmental protection.

The invention relates to a method for strengthening purification and separation of artemisinin by a chitosan functional membrane. An extractant is added to an extract containing artemisinin and wax oil to obtain an extraction solution, the chitosan functional membrane or a modified chitosan functional membrane is added to the extraction solution, and separation and purification are performed to obtain artemisinin. The chitosan functional film or the modified chitosan functional film can adsorb the wax oil in the extraction solution, and the wax oil is easily separated from artemisinin after being adsorbed, so that high-purity artemisinin is obtained. At the same time, the chitosan functional film or the modified chitosan functional film has simple preparation method, and abundant and non-toxic and harmless raw materials. The method can also reduce a number of crystallization times and a crystallization time required in a process of obtaining an artemisinin product, and is an efficientpurification and separation method.

The invention discloses a method for purifying sucralose-6-ethyl ester. The method comprises: a secondary boiling step: taking a boiled and negative-pressure-treated mother liquor of sucralose-6-ethyl ester; ‑Adding a predetermined proportion of water to the ethyl ester mother liquor, fully stirring and heating it for boiling, stirring and boiling for a preset time, and then solid-liquid separation to obtain a secondary boiling mother liquor in which sucralose‑6‑ethyl ester is dissolved; phase-separated extraction step : the secondary boiled mother liquor is left to stand for phase separation, the upper phase after the phase separation is taken, and the alkane extractant is used for extraction at a preset temperature to remove the residual white oil in the upper phase; recrystallization and purification step: extracting the obtained The lower layer effluent obtained is evaporated to obtain a solid, and the solid is purified by recrystallization to obtain sucralose-6-ethyl ester; recovery and circulation step: the upper layer effluent after extraction is separated, and the alkane extractant is recovered and recycled to the phase-separating extraction step use. The method is simple, efficient, and low in cost, can effectively remove trace amounts of white oil, and improve the purity of sucralose-6-ethyl ester.

The invention relates to a method for preparing lithium hydroxide from spodumene and a method for removing sodium and potassium, and belongs to the technical field of lithium extraction from ores. The technical problem solved by the present invention is to provide a method for preparing lithium hydroxide from spodumene. The method comprises: 1) roasting; 2) acidifying, leaching, and filtering to obtain lithium sulfate mother liquor; 3) removing high-valent metal ions in lithium sulfate mother liquor; 4) removing sodium and potassium by electrodialysis; 5) bipolar membrane electrolysis to obtain hydrogen Lithium oxide solution and dilute sulfuric acid; 6) concentration and crystallization of lithium hydroxide solution to obtain lithium hydroxide product. The method of the present invention can produce battery-grade lithium hydroxide from spodumene, and the method is simple, environmentally friendly and low in cost; at the same time, it does not need to add caustic soda and freeze, and has high economic value. Before bipolar membrane electrolysis, ordinary electrodialysis removes sodium Potassium, so that the purity of the obtained product is greatly improved compared with the traditional method, and the direct crystallization can reach the battery level, which meets the trend and requirements of green and sustainable development.

The invention relates to a ganciclovir recovery method, which comprises the steps that ganciclovir mother solution is concentrated, alkaline solution is added to adjust pH value to 10.0-13.5, temperature is kept to be constant at 20-60 DEG C for 10-60 minutes, active carbon is added and agitation is conducted for 1-3h, filtration is conducted, organic solution is added in filtrate to precipitate white crystals, filtration is conducted, filter cakes are dissolved in deionized water, hydrochloric acid is added to regulate pH value to 5-6, solid sediment is precipitated, after the solid sedimentis heated and dissolved, the temperature of the solid sediment is slowly decreased by 0-30 DEG C to precipitate crystals, and the crystals are filtered and dried to obtain high-purity ganciclovir products. Compared with the prior art, the invention has the advantages of simple operation, high yield, low cost, no pollution and the like.

The present invention relates to a crystallization method of abamectin B 1a. Said method includes the following steps: using crystallization solvent n-butanol to stir and dissolve primary crude powder of abamectin B 1a at 75-100deg.C to saturation, filtering while the saturated solution is hot to obtain clear hot-saturated solution; slowly cooling said solution to that when the supersaturation degree is 1-3, adding crystal seeds, constant stirring for 20-60min, its stirring speed is 120-300rpm, and cooling to make crystallization, fitering crystal slurry or centrifugally-separating said crystal slurry, washing crystal and drying so as to obtain the invented abamectin B 1a.

The invention relates to a production process of abamectin fine powder. The production process method comprises the steps: extracting fermentation liquid filter cake with sec-butyl acetate for three times; combining organic-ester-phase extracts, adding tetrabutyl ammonium bromide aqueous solution for washing, and filtering, concentrating filtrate, and cooling and crystallizing to obtain once crude product; and dissolving the once crude product with ethanol, filtering, naturally cooling to room temperature, adding water at a volume ratio of ethanol to water being (7 : 1)-(4 : 1) for dilution crystallization, washing and drying to obtain the abamectin fine powder product. By adopting the method, the abamectin crystal product with higher purity and yield can be obtained; and compared with the traditional methods, the method has the advantages that the crystallizing time is shorter, the repeated crystallizing frequency is reduced and the production cost is low, thereby being a low-cost and high-efficiency production process of the high-purity abamectin fine powder.

The invention relates to a preparation method of high-purity abamectin B2a, which comprises the steps of concentrating the abamectin B1a crystallization mother liquor under vacuum conditions to no fraction to obtain a thick ointment; adding an extractant for extraction to obtain an extract , and then use saturated brine to wash the extract for 2 to 3 times, remove the water phase to obtain n-butyl acetate solution; cool the obtained n-butyl acetate solution to crystallize, grow crystals, and suction filter to obtain crude crystals of abamectin B2a ; Abamectin B2a coarse crystal recrystallization suction filtration, drying, to obtain high-purity avermectin B2a fine powder. The present invention uses the environment-friendly non-toxic solvent n-butyl acetate to replace the toxic solvent aromatic hydrocarbon to produce abamectin B2a high-quality goods. During the production operation, it causes little harm to the health of on-site employees, and the pollution to the environment is also relatively small. In addition, n-butyl acetate is adopted as B2a as crystallization solvent, and the purity of the obtained abamectin B2a fine powder is above 95%.

The invention discloses a preparation method of griseofulvin, which is composed of the following steps: A, heating the griseofulvin fermented liquid, adding calcium oxide to adjust the pH, separating the solid and liquid from the plate and frame, adding calcium oxide to the filter cake to granulate, Extract with acetone to obtain griseofulvin acetone extract; B. Griseofulvin acetone extract is decolorized by activated carbon column to obtain griseofulvin acetone decolorization liquid, and the decolorization liquid enters the concentration tank, concentrates and crystallizes to obtain griseofulvin wet crystals C, griseofulvin wet crystals are washed once with dichloromethane and ethanol mixed solution under stirring, and then washed once with the medicinal ethanol of 95% with concentration under stirring, dried in a vacuum drier, ultrafinely pulverized, Get griseofulvin products. Compared with the traditional preparation method, the present invention reduces the number of crystallization times in the process of preparing griseofulvin in the prior art, effectively avoids the yield loss caused by the recrystallization of griseofulvin, and can increase the total yield of griseofulvin Increased by 7 to 10%, greatly reducing production costs.

The invention discloses a method for preparing high-purity stigmasterol from phytosterol oleate. The method comprises the following steps of taking phytosterol oleate as a raw material, and performingsubzero fractionation, saponification, solid-liquid separation and two times of crystallization and purification to obtain a stigmasterol product with purity equal to 95% or more. Compared with the prior art, in the method, the phytosterol oleate is taken as the raw material to prepare the high-purity stigmasterol, the method has fewer crystal number of times and is simple in operation steps, thesolvent used for crystallization and purification can be recycled, making full use of resources is realized, and the production cost is lowered.