41 results about "Acetaldoxime" patented technology

The invention discloses a reduction method for graphene oxide. The method comprises the following steps: using acetone oxime, acetaldoxime or methyl ethyl ketoxime as a reducing agent, and then preparing the graphene by reducing the graphene oxide in a graphene oxide aqueous solution the pH value of which is 6-10, wherein the reaction temperature is 80-100 DEG C and the mass ratio of graphene oxide to the reducing agent acetone oxime, acetaldoxime or methyl ethyl ketoxime is 1: (0.2-5). The method is characterized in that the oximido having lower toxicity is used as the reducing agent and thegraphene is acquired by reducing the graphene oxide by using a chemical reduction method. The preparation method is simply and easily performed, the reaction process is easily controlled, no special requirement for equipment exists, the cost is low, the pollution is free, and the method is easily popularized and used.

The invention provides a new preparation method of cyclohexanone oxime, and the preparation method comprises performing a hydrolysis reaction of 4 or less than 4 carbon atom containing oxime such as acetaldoxime, acetone oxime or butanone oxime and the like which is produced by an ammoxidation method and phosphoric acid added in a phosphate buffer solution to obtain an inorganic liquid containing hydroxylamine phosphate, then performing an oximation reaction of the inorganic liquid and cyclohexanone to obtain the high purity cyclohexanone oxime. According to the preparation method, due to the direct oximation reaction of the hydroxylamine phosphate and the cyclohexanone, the shortcoming that the cyclohexanone oxime prepared by the direct ammoxidation method is high in impurity content and is difficult to separate, and thus affecting the quality of caprolactam prepared from the cyclohexanone oxime can be overcomed; at the same time, the advantages of a plurality of processes for industrial production of the cyclohexanone oxime are combined, the inorganic liquid cycle can be realized, the high purity cyclohexanone oxime is prepared, the process cycle is realized, and the preparation method is conducive to energy saving and consumption reduction, and the realization of safe, environmentally friendly, low-cost and high-quality production.

The invention relates to a method for preparing anhydrous acetaldoxime, which comprises the following steps: adding a hydroxylamine solution, aldehyde and alkali into an oximation reactor with a stirring or external circulating system to perform reactions so as to prepare aldehyde oximation solution; passing the aldehyde oximation solution through a cooler and then sending the same into a liquid-liquid separator; sending the upper layer oil phase into a rectifying tower A to perform rectification so as to obtain an acetaldoxime aqueous solution of which the mass percent is about 50 percent and anhydrous acetaldoxime; and sending the solution on the lower layer and containing an inorganic salt into a rectifying tower B to perform rectification so as to obtain the acetaldoxime aqueous solution of which the mass percent is about 50 percent from the tower top, wherein the product at the bottom of the tower is acetaldoxime-free inorganic salt aqueous solution. The method makes full use of the functions that the solubility of the acetaldoxime is reduced at a low temperature and the inorganic salt is salted out, avoids the defects that the conventional extraction method and the vapor phase extraction method consume a large amount of organic solvent, are not environment-friendly and have complex and difficultly-controlled devices in the preparation of the anhydrous acetaldoxime, effectively improves the production condition, is an environment-friendly novel process, and has excellent economic and social benefits.

The invention discloses a synthesis method of an isocoumarin derivative. The method comprises the following steps: adding 3-hexyl-4-cyan-6,7-dimethoxy isocoumarin (A), a cuprous catalyst and acetaldoxime (B) in a reaction vessel, adding a solvent N,N-dimethyl formamide (DMF), stirring and refluxing; reacting for 1 hour, cooling, filtering reaction solution in vacuum, and adding a certain amount of water in the filtrate, filtering separated solid in vacuum, drying and low-temperature crystalizing obtained coarse product so as to obtain a target product 3-hexyl-4-acylamoni-6,7-dimethoxy isocoumarin (C). The method for translating the isocoumarin into acylamino is scientific and reasonable, the step is simple, the reaction time is short, the selectivity is good, the translation rate is high, the product is easy to purify; cuprous salt is firstly used as the catalyst, and the catalysis efficiency is high in comparison with the reported cupric, in particular, the cuprous has good catalysis effect on cyan hydrolysis with large steric hindrance.

The invention provides a mercaptoacetone oxime cleaner production method and system. The method at least comprises the following steps that (1) aldoxime and a solution containing chloride ions are added into an anode chamber of an electrolytic cell, an electrolyte solution is added into a cathode chamber, energization is conducted for electrolysis, and a solution containing chloroacetaldehyde oxime is formed in the anode chamber; and (2) the solution containing the chloroacetaldehyde oxime is mixed and reacted with methyl mercaptan, a solution containing mercaptoacetone oxime is obtained, separated and purified, and a finished mercaptoacetone oxime product is obtained. Hypertoxic chlorine is not used, brine waste is effectively avoided, the environment protection problem caused by waste salts in existing mercaptoacetone oxime production processes is solved, the raw material consumption is effectively reduced, generated hydrogen can be used as clean fuel, and the raw material utilization rate is effectively improved.

The invention discloses a method for preparing acetaldoxime. The method is characterized by carrying out a high-selectivity acetaldoxime combination reaction on acetaldehyde, ammonia and an alcohol solvent in a liquid phase by taking titanium silicate molecular sieve as a catalyst and taking hydrogen peroxide as an oxidant, and distilling and purifying the reaction solution to acquire the acetaldoxime, wherein the mass ratio of the acetaldehyde, the ammonia, the alcohol solvent and the catalyst is 1: (0.38-0.78): (2-10): (0.05-0.68). Compared with the prior art, the method for preparing the acetaldoxime has the advantages of high conversion rate of acetaldehyde, good selectivity and high utilization rate of hydrogen peroxide; the reaction process is simple and is environment-friendly and pollutions to the environment are reduced; the industrial production is facilitated; and the development of green chemistry is promoted.

The invention discloses a method for synthesizing m-trifluoromethyl acetophenone which is an important intermediate for medicine, pesticide and pigment. According to the method, m-trifluoromethylaniline as the initial raw material is diazotized to prepare a diazonium salt which is coupled with acetaldoxime under the catalysis of a copper salt by controlling the pH value at 4-4.5 and the temperature at 0-5 DEG C, and the coupling compound is extracted by an organic solvent and then hydrolyzed by using hydrochloric acid to obtain the m-trifluoromethyl acetophenone. The total yield of the m-trifluoromethyl acetophenone produced according to the method is more than 70 percent; and the reaction conditions of the method are simple, the yield is high, the pollution is small, and the method is applied to industrial production.

The invention discloses light-fast high-performance printing ink which comprises a binder, a filler, a light stabilizer, an anti-oxidant, a lubricant, an anti-setoff agent, a pigment and a solvent, wherein the binder is nitrile butadiene rubber; the filler is powdered cork wood; the light stabilizer is 2,4-dihydroxybenzophenone; the anti-oxidant is acetaldoxime; the lubricant is cocamidopropyl dimethyl tertiary amine; the anti-setoff agent is corn starch; the pigment is carbon black; the solvent is cyclohexanone. As the printing ink comprises the binder, the filler, the light stabilizer, the anti-oxidant, the lubricant, the anti-setoff agent, the pigment and the solvent, the printing ink is high in light stability and quality, resistant to oxidation, durable, free from setoff, long in service life, and good in using effect.

The invention provides a preparation method of 2,4-difluoroacetophenone. The 2,4-difluoroacetophenone is synthesized by using 2,4-difluoroaniline, acetaldoxime and copper sulfate; the pH is adjusted to 3-6 in a reacting process, and is preferably equal to 4; after a reaction, a product is distilled by using water vapor; and after benzene extraction, post-treatment is performed by using a reduced-pressure rectification method. Reaction conditions are mild, operation is simple, and the yield is high.

The invention provides a method for synthesizing a dicyclohexyl o-fluoroethylbenzene liquid crystal compound, comprising the following steps: (1) using o-fluoro-p-bromoaniline as the raw material to react with sodium nitrite in the presence of hydrochloric acid to generate a compound (I); (2) reacting the compound (I) with acetaldoxime under the catalysis of blue copperas to obtain a compound (II); (3) hydrolyzing the compound (II) with hydrochloric acid to obtain a compound (III); (4) carrying out Huang-Minlon reduction on the compound (III) to obtain a compound (IV); (5) preparing the compound (IV) into a grignard reagent in tetrahydrofuran or diethyl ether, then reacting the grignard reagent with alkyldicyclohexylanone, and acidizing and dehydrating the reactant to obtain a compound (V); and (6) carrying out hydrogenation reduction on the compound (V) to obtain the compound shown in the molecular formula. By synthesizing the intermediate o-fluoro-p-bromoethylbenzene, the invention provides a new method for synthesizing bicyclohexane liquid crystal compound. The method is simple to operate and safe and can effectively improve the purity and the yield of the target compound.

The invention relates to the field of chemical engineering, in particular to a preparation method of acetaldoxime. According to the preparation method of acetaldoxime, water is used as a solvent, hydroxylamine phosphate and acetaldehyde react to prepare acetaldoxime, the method is high in yield and simple in process, and hydroxylamine phosphate serving as a material is recycled; the method has theadvantages of the complex process, the short reaction flow, no byproduct, no use of toxic and harmful raw materials and less discharge of waste water and waste acid. A graphene modified adsorbent filler is adopted to refine a product solution, and the adsorbent resin has a very good adsorption effect on organic matter residues in wastewater, can be repeatedly recycled, and is greener, safer and more energy-saving compared with a traditional method used in the prior art.

The invention relates to a synthetic method of 1-(4-chlorophenyl)-2-cyclopropyl-1-propanone. The synthetic method comprises steps as follows: (1), hydroxy lamine hydrochloride is dissolved in a solvent, alkali is added, the pH (potential of hydrogen) value is adjusted, a raw material of cyclopropyl propionaldehyde is added at the appropriate temperature for a reaction, and cyclopropyl acetaldoxime is obtained through extraction, concentration and drying after the reaction ends; (2), newly prepared p-chlorophenyl diazonium salt and a catalyst are added to cyclopropyl acetaldoxime at the lower temperature, acid is added, the mixture is heated to have a reaction, and 1-(4-chlorophenyl)-2-cyclopropyl-1-propanone is obtained through aftertreatment after the reaction ends. The synthetic route is shown in the specification. The synthetic method has the advantages as follows: the cost of raw materials is low, the overall yield of the reaction is high, the technological operation is safe, aftertreatment is simple and convenient, and the synthetic method has industrial application value.

The invention discloses chloro acetaldoxime cleaner production and a RuO2@TNTs anode used for cleaner production. A preparation method of the anode comprises the steps that a titanium mesh subjected to chemical degreasing and cleaning is arranged in a polishing agent for chemical polishing treatment; the titanium mesh is anodized through a two-electrode working system; a newly formed unstable surface layer formed after anodizing of the titanium mesh anode is removed through adhesive tape adsorption; the titanium mesh is used as the anode, the two-electrode working system is used continuously,the voltage is increased, and a nano-structure titanium dioxide array anode (TNTs) is obtained through oxidizing the TNTs anode is oxidized and annealed; ruthenium trichloride, distilled water and concentrated hydrochloric acid are mixed into a mixed solution with 5mM ruthenium trichloride and 0.5 wt% of hydrochloric acid; the annealed TNTs anode is put into the mixed solution; then the mixed solution where the TNTs anode is soaked in is subjected to hydro-thermal treatment; and the TNTs anode is oxidized again and then annealed, and the in-situ-grown nano-structure RuO2@TNTs anode is obtained.

The invention discloses a method for synthesizing amide through nitrile hydrolysis. The method comprises the following steps: adding nitrile, acetaldoxime, water, a water-soluble rhodium complex to a reaction vessel, and cooling to room temperature after reaction of a reaction mixture for several hours at the temperature of 50-80 DEG C; and adding ethyl acetate for extraction so as to obtain an organic layer, and carrying out rotary evaporation to remove a solvent, thus obtaining a target product. Compared with a method for synthesizing amide through nitrile hydrolysis by using oxime as a water source in a transition metal catalysis process, the method has the advantages that a used catalyst is low in loading and does not contain a phosphine ligand seriously polluting environments, synthesis can be performed in air, and nitrogen protection is not needed; and therefore, the method meets the green chemistry requirements and has a wide development prospect.

The invention discloses a preparation method of methomyl. Methylthio acetaldoxime is used as a raw material and reacts with methyl isocyanate in water under the action of a phase transfer catalyst, the temperature is raised to 50-60 DEG C after the reaction is finished, cooling crystallization and filtration are performed after the material is completely dissolved, filtrate and a filter cake are obtained, the filtrate is extracted with an organic solvent, desolvation is then carried out, desolventized solids and the filter cake are combined and dried, and a methomyl product is obtained. The preparation method has the advantages of high yield, low cost, simplicity and convenience in operation and the like.

The invention discloses a method for preparing acetaldoxime by adopting a continuous method, which comprises the steps of filling quartz sand into a reactor, introducing a hydroxylamine hydrochlorideaqueous solution, acetaldehyde and ammonia water serving as raw materials into the reactor, controlling reaction temperature and reaction pressure, adjusting the pH, and collecting the obtained reaction liquid. GC detection shows that that the conversion rate of hydroxylamine hydrochloride is greater than or equal to 99%, and the acetaldoxime selectivity is greater than or equal to 99%. The methodfor continuously synthesizing acetaldoxime has the characteristics of simplicity in operation, safety, reliability, complete hydroxylamine hydrochloride reaction, high selectivity and the like.

The invention relates to the technical field of organic chemical synthesis, in particular to a preparation method of acetaldoxime. The preparation method of acetaldoxime includes the following steps of 1, stirring and dissolving hydroxylamine and distilled water, then adding acetaldehyde and catalytic acetic acid dropwise under an ice water bath condition, conducting stirring for a reaction at 0-10 DEG C for 10-30 minutes after the dropwise addition is completed, and then obtaining an acetaldoxime solution; 2, using dichloromethane for extracting the acetaldoxime solution in step 1, using anhydrous sodium sulfate for drying an extracted liquid, then conducting fractional distillation under normal pressure to obtain a solvent at first, conducting distillation under reduced pressure to collect fractions, and obtaining a colorless transparent liquid, namely acetaldoxime. The preparation method of acetaldoxime adopts acetic acid as a catalyst, hydroxylamine and acetaldehyde are adopted asraw materials to prepare the acetaldoxime solution, and then through extraction, drying, fractionation under normal pressure and distillation under reduced pressure, the colorless transparent liquid,namely acetaldoxime, is obtained. Obtained acetaldoxime is anhydrous, the purity is higher than or equal to 99%, and the yield is higher than or equal to 92%.

The invention discloses a reduction method for graphene oxide. The method comprises the following steps: using acetone oxime, acetaldoxime or methyl ethyl ketoxime as a reducing agent, and then preparing the graphene by reducing the graphene oxide in a graphene oxide aqueous solution the pH value of which is 6-10, wherein the reaction temperature is 80-100 DEG C and the mass ratio of graphene oxide to the reducing agent acetone oxime, acetaldoxime or methyl ethyl ketoxime is 1: (0.2-5). The method is characterized in that the oximido having lower toxicity is used as the reducing agent and thegraphene is acquired by reducing the graphene oxide by using a chemical reduction method. The preparation method is simply and easily performed, the reaction process is easily controlled, no special requirement for equipment exists, the cost is low, the pollution is free, and the method is easily popularized and used.

The invention provides an electroplating solution containing a novel additive and application of the electroplating solution in copper electroplating. The pyridine-2-acetaldehyde oxime methyl iodide is used as a novel copper electroplating additive (leveling agent) for the copper electroplating process, the cost is low, safety and no pollution are achieved, and the novel additive stably exists in the electroplating liquid. The novel additive is applied to the electrocoppering process, compact filling from bottom to top can be achieved, the surface of a plating layer is bright and flat, different adsorption behaviors of the additive can be regulated and controlled by regulating and controlling distribution of current density at interfaces of the inner surface and the outer surface of a micropore, and therefore the additive can be widely applied to high-density interconnection of electronic devices and can be applied to electrocoppering. And high-quality and high-stability signal transmission is satisfied.

The invention discloses a preparation method of a novel boiler deoxidant, and belongs to the technical field of chemical synthesis. The invention provides a preparation method of a novel boiler deoxidant, which comprises the following steps of: dehydrating isochromanone serving as a raw material and hydroxylamine sulfate in a solvent (water, ethanol or methanol) under an acidic condition to generate isochromanone oxime, and mixing the isochromanone oxime with other oximes, a dispersing agent and the like in parts by weight to prepare the required boiler deoxidant. The deoxidant is prepared from 3 to 5 parts of isochroman ketoxime, 12 to 16 parts of acetoxime, 12 to 14 parts of acetaldoxime, 8 to 12 parts of carbohydrazide, 4 to 7 parts of a dispersant, 5 to 10 parts of a pH regulator, 5 to 10 parts of a catalyst and 40 to 50 parts of water, wherein the other raw materials are prepared from 3 to 5 parts of isochroman ketoxime, 12 to 16 parts of acetoxime, 12 to 14 parts of acetaldoxime, 8 to 12 parts of carbohydrazide, 4 to 7 parts of a dispersant, 5 to 10 parts of a pH regulator, 5 to 10 parts of a catalyst and 40 to 50 parts of water. According to the preparation method, boiler pipelines, equipment and the like can be passivated while low toxicity, high efficiency and high speed can be guaranteed, equipment corrosion damage caused by metal oxide deposition of a boiler is prevented, and the product is non-toxic, harmless and mild to the environment.

The invention belongs to the technical field of after treatment of nuclear fuels, and discloses a method for stabilizing a U(IV) valence state in TBP. The method is implemented by introducing acetaldoxime into an organic phase of TBP; or introducing the acetaldoxime into a water phase, and then extracting the acetaldoxime into the organic phase of the TBP by a way of extraction, wherein the concentration of the acetaldoxime introduced into the organic phase of the TBP is 2-100mmol / L, and the concentration of the acetaldoxime introduced into the water phase is 20-1000mmol / L. The method has the advantages of being simple, and being capable of enabling the stabilization time of the U(IV) valence state in the TBP to be long.

The invention discloses a composite absorbent for capturing carbon dioxide in flue gas and application of the composite absorbent, and relates to the technical field of carbon dioxide composite absorbents. The flue gas CO2 trapping composite absorbent and the matched macromolecular anti-degradation agent disclosed by the invention have efficient absorptivity, strong degradation resistance and industrial suitability, the material takes aminoethylethanolamine as a main absorbent and is matched with a 2-amino-2-methyl-1-propanol auxiliary absorbent and an N-methylpiperazine activator, and high CO2 selectivity is realized through mass ratio optimization; the anti-degradation agent is prepared by compounding a bismuth reagent and a macromolecular anti-degradation agent, the macromolecular anti-degradation agent is subjected to a Witt ig reaction, a thiol click reaction and other multi-step processes, active units such as hindered phenol, benzotriazole and acetaldoxime are integrated, free radicals can be removed, metal ions can be passivated, NOx can be neutralized, the amine degradation rate is reduced, and an efficient, stable and economical solution is provided for CO2 trapping.

The invention relates to a treatment method for recycling isatin wastewater. The invention provides the treatment method for recycling the isatin wastewater, in order to solve the technical problem of filling in the gap of the prior art. The method comprises the following steps of: (1) controlling the mass concentration of sulfuric acid to be between 10 and 40 percent when materials are precipitated from the isatin, filtering a product, collecting waste liquid, neutralizing until the waste liquid is neutral by using inorganic base, and absorbing and filtering to remove impurities to obtain light yellow solution; and (2) taking 100 weight parts of light yellow solution obtained in step (1), adding 6 weight parts of hydroxylamine sulfate, dripping 11 weight parts of trichloracetic aldehyde, dripping 6 weight parts of aniline at normal temperature, raising the temperature to be between 75 and 100 DEG C after the materials are added, keeping the temperature for 1 to 3 hours, reducing to room temperature, filtering, collecting a filter cake, and drying to obtain a dry N-acetaldoxime aniline product. The method has the advantages of simple structure, environment friendliness and economization, and is a powerful weapon of economization, potential tapping and reduction of wastewater discharge of the conventional isatin production enterprises.

The invention discloses an environment-friendly efficient boiler deoxidant which is prepared from the following raw materials in parts by weight: 20-25 parts of dimethyl ketoxime, 13-18 parts of diacetylmonoxime, 10-12 parts of acetaldoxime, 12-17 parts of carbazide, 6-10 parts of a dispersing agent, 5-10 parts of a pH regulator, 3-7 parts of a catalyst and 30-40 parts of purified water. And the used oxime raw materials such as dimethyl ketoxime, diacetylmonoxime and acetaldoxime have relatively strong reducibility, have the characteristics of low toxicity, high efficiency and high speed in the aspect of oxygen removal, and play a role in passivation protection on the surface of the boiler. And meanwhile, the stability is high, and a good oxygen removal function is achieved within a wide temperature and pressure range. The three substances are mixed with carbazide which also has a deoxidizing effect to enhance the deoxidizing capability, and meanwhile, the dispersing agent, the catalyst and the pH regulator are added to ensure smooth and safe reaction, reduce the generation of derivatives, improve the substance stability and accelerate the preparation rate.

The invention discloses a method of adjusting pH value of boiler water of a boiler. The method comprises the following steps: when the pH value of boiler water of the boiler is lower than a predetermined pH value, adding an alkaline solution and an oxime compound into the boiler water of the boiler; when the alkaline solution is adopted to adjust the pH value of boiler water of the boiler, solving the problem that the pH value of boiler water of the boiler is low by adding the oxime compound into boiler water of the boiler and meanwhile, avoiding the problem that the pH value of boiler water of the boiler is great in fluctuation in the adjusting process, wherein the adjusting curve slowly ascends; and adding the oxime compound as an effective chemical deoxygenator to chemically deoxygenate in a boiler drum and the boiler main body, consume free oxygen molecules in the boiler main body and prevent the surface of metal of the boiler from being corroded by oxygen, wherein the oxime compound has reducibility, protects the boiler main body and has a good corrosions effect. The adjusting method is simple in operation and quick and effective. Acetaldoxime is directly added at the inlet of the equipment without adding large instruments and equipment.

The invention is suitable for the technical field of chemical industry production, and provides a production method of thiophene-2-ethylamine. The production method comprises the steps of placing thiophene-2-ethanol and an oxidizing agent in a first solvent to carry out an oxidation reaction to obtain thiophene-2-acetaldehyde; putting thiophene-2-acetaldehyde and hydroxylamine hydrochloride into asecond solvent to react, and purifying to obtain thiophene-2-acetaldoxime; and putting thiophene-2-acetaldoxime and sodium borohydride into a third solvent to carry out reduction reaction, and purifying to obtain thiophene-2-ethylamine. The production method of thiophene-2-ethylamine provided by the invention is simple in process, and comprises the steps of by taking thiophene-2-ethanol as a rawmaterial, firstly preparing thiophene-2-acetaldehyde by an oxidation method, then preparing thiophene-2-acetaldoxime from thiophene-2-acetaldehyde and hydroxylamine hydrochloride, and then reducing thiophene-2-acetaldoxime into a product thiophene-2-ethylamine. The method has the advantages of high product purity, high product conversion rate and high production efficiency.

The invention discloses a method for synthesizing amide through nitrile hydrolysis. The method comprises the following steps: adding nitrile, acetaldoxime, water, a water-soluble rhodium complex to a reaction vessel, and cooling to room temperature after reaction of a reaction mixture for several hours at the temperature of 50-80 DEG C; and adding ethyl acetate for extraction so as to obtain an organic layer, and carrying out rotary evaporation to remove a solvent, thus obtaining a target product. Compared with a method for synthesizing amide through nitrile hydrolysis by using oxime as a water source in a transition metal catalysis process, the method has the advantages that a used catalyst is low in loading and does not contain a phosphine ligand seriously polluting environments, synthesis can be performed in air, and nitrogen protection is not needed; and therefore, the method meets the green chemistry requirements and has a wide development prospect.

The invention provides a method for synthesizing a dicyclohexyl o-fluoroethylbenzene liquid crystal compound, comprising the following steps: (1) using o-fluoro-p-bromoaniline as the raw material to react with sodium nitrite in the presence of hydrochloric acid to generate a compound (I); (2) reacting the compound (I) with acetaldoxime under the catalysis of blue copperas to obtain a compound (II); (3) hydrolyzing the compound (II) with hydrochloric acid to obtain a compound (III); (4) carrying out Huang-Minlon reduction on the compound (III) to obtain a compound (IV); (5) preparing the compound (IV) into a grignard reagent in tetrahydrofuran or diethyl ether, then reacting the grignard reagent with alkyldicyclohexylanone, and acidizing and dehydrating the reactant to obtain a compound (V); and (6) carrying out hydrogenation reduction on the compound (V) to obtain the compound shown in the molecular formula. By synthesizing the intermediate o-fluoro-p-bromoethylbenzene, the invention provides a new method for synthesizing bicyclohexane liquid crystal compound. The method is simple to operate and safe and can effectively improve the purity and the yield of the target compound.

The invention relates to a method for preparing anhydrous acetaldoxime, which comprises the following steps: adding a hydroxylamine solution, aldehyde and alkali into an oximation reactor with a stirring or external circulating system to perform reactions so as to prepare aldehyde oximation solution; passing the aldehyde oximation solution through a cooler and then sending the same into a liquid-liquid separator; sending the upper layer oil phase into a rectifying tower A to perform rectification so as to obtain an acetaldoxime aqueous solution of which the mass percent is about 50 percent and anhydrous acetaldoxime; and sending the solution on the lower layer and containing an inorganic salt into a rectifying tower B to perform rectification so as to obtain the acetaldoxime aqueous solution of which the mass percent is about 50 percent from the tower top, wherein the product at the bottom of the tower is acetaldoxime-free inorganic salt aqueous solution. The method makes full use of the functions that the solubility of the acetaldoxime is reduced at a low temperature and the inorganic salt is salted out, avoids the defects that the conventional extraction method and the vapor phase extraction method consume a large amount of organic solvent, are not environment-friendly and have complex and difficultly-controlled devices in the preparation of the anhydrous acetaldoxime, effectively improves the production condition, is an environment-friendly novel process, and has excellent economic and social benefits.