13 results about "Bromide methyl" patented technology

The invention belongs to the technical field of organic synthesis, and particularly relates to a synthesis method of an isoxazole compound under a visible light catalysis condition. The method comprises the following steps: dissolving a compound 1 in 1, 2-dichloroethane, then adding tert-butyl nitrite, tribromomethane, alkali and a photocatalyst, in an inert gas environment, irradiating with visible light and stirring at room temperature to react, after the reaction is completed, reducing pressure to remove a solvent, and then performing silica gel column purification on a crude product to obtain a product, namely the isoxazole compound. The brand-new method for preparing the isoxazole compound through visible light catalysis is developed, the conditions of high temperature and high pressure in a traditional synthesis method are avoided, energy consumption and environmental pollution are remarkably reduced, and the yield of the isoxazole compound is effectively increased by regulating and controlling reaction conditions and optimizing raw material selection and proportion.

The present application relates to a kind of preparation method of trifluoromethyl pyrazole compound, belong to the technical field of organic synthesis.The specific method is: (1) trifluoroacetyl ethyl acetate is first with hydrazine hydrate cyclization reaction and generates compound of formula III;(2) under the catalysis of base, compound of formula III is reacted with difluoromethylation reagent and generates compound of formula II;(3) compound of formula II is reacted with methylating agent and obtains compound of formula I;The difluoromethylation reagent is difluoro-monochloromethane or sodium difluoro-monochloroacetate;The methylating agent is chloromethane, bromomethane, iodomethane, dimethyl sulfate or dimethyl carbonate.The present application is prepared by changing reaction route, and the higher-priced raw material methylhydrazine is replaced, and isomer impurity is no longer generated in the product prepared.Not only raw material cost is reduced, but also the purity of product is improved.

The application discloses a kind of ultrafast metal-free and solvent-free preparation method for preparing symmetric and asymmetric disulfide, which comprises the following steps: at room temperature, raw material R-SH, R'-SH and oxidant and base are added to reaction bottle, shake rapidly for 10-30 seconds, and R-S-S-R' is prepared after the reaction product is purified;Wherein R in R-SH is aliphatic or aromatic group, R' in R'-SH is aliphatic or aromatic group;R in R-SH and R' in R'-SH are same or different;The aromatic group has substituent or no substituent, and the aliphatic is straight chain or has branch;The oxidant is chloroform, and the base is N, N-diisopropylethylamine (DIPEA).The method is simple in operation, high in yield (60-99%), ultrafast in reaction kinetics, greatly improves production efficiency, wide in applicability, avoids the use of organic reaction solvent, raw material is cheap and easy to obtain, and does not contain residual metal and other sticky contaminants from reagent and ligand, provides a safer and more effective method for the synthesis and production of symmetric and asymmetric disulfide-containing compounds.

This utility model discloses a fruit fumigation and preservation device, relating to the field of fruit preservation technology. It includes an outer casing with an array of tray structures slidably connected within it. A pneumatic device is installed within the tray structures, and a corresponding braking structure is installed within the outer casing. This utility model introduces methyl bromide gas into an installation pipe via an air inlet pipe. The accumulation of the methyl bromide gas causes the sliding pipe to slide upwards, which in turn compresses the movable top cover to slide upwards. The methyl bromide gas in the sliding pipe then flows through the air outlet into the fruit tray and its frame. Due to the relatively large molecular weight of methyl bromide gas, it accumulates at the bottom of the fruit tray. As the methyl bromide gas accumulates, it forces air outwards through the gap between the tray frame and the movable top cover, ensuring sufficient contact between the methyl bromide gas and the fruit, thereby reducing the consumption of methyl bromide gas.

This invention provides a method for preparing deuterated paraoxymethylene. Specifically, this invention provides a method for preparing deuterated paraoxymethylene comprising the following steps: (S1) deuteration of dibromomethane; (S2) synthesis of deuterated methylene diacetate; and (S3) synthesis of deuterated paraoxymethylene.

The invention discloses a method for extracting and converting bromine ions dissolved in a water body and detecting stable bromine isotopes, and belongs to the field of isotope detection methods. The method comprises the following steps: oxidizing bromide ions in a water body by using acidic sodium dichromate based on the oxidation-reduction characteristic of the bromide ions in the water body to obtain bromine gas, reacting the bromine gas with an alkaline solution to obtain sodium bromide, adding silver ions into the solution to generate silver bromide precipitates, drying the precipitates, quantitatively putting the precipitates into a jaw headspace bottle in a dark environment, and adding methyl iodide; reacting under optimized conditions to generate methyl bromide gas; a gas isotope mass spectrometer and a gas chromatograph which are provided with receiving cups with the mass numbers of 94 and 96 are used in a combined mode, interference of impurity gas is eliminated through modified Isolink II equipment, after bromomethane mixed gas is separated through a chromatographic column, the impurity gas is emptied, bromomethane enters the mass spectrometer, and the bromine isotope ratio is accurately measured. The method can be used for evaluating and researching sources, causes and formation hydrogeochemical and physical processes of oil field water, underground brine, salt water and the like.

The present application relates to a preparation method of monofluoromethane, the preparation method comprises the following steps: (1) mixing halogenated methane, iodide and organic solvent, and reacting to obtain an organic solution of methyl iodide; the halogenated methane comprises liquid monochloromethane and / or monobromomethane; (2) mixing fluoride, a promoter and the organic solution of methyl iodide obtained in step (1), and reacting to generate gaseous product monofluoromethane. The preparation method provided by the present application does not require the use of a catalyst, and the organic solvent can be reused, thereby reducing production costs; the preparation method provided by the present application is simple to operate, the product quality is stable, the purity is high, and is suitable for continuous production.

The invention discloses a photoacoustic spectrometry fumigation gas concentration analysis system, and relates to the technical field of fumigation operation. The system comprises a system cabinet, a fumigation gas concentration analysis module which is arranged in the system cabinet and detects the concentration of methyl bromide gas based on a photoacoustic spectrum principle, and an environmental parameter detection module which is arranged in the system cabinet. According to the invention, based on a photoacoustic spectrum principle, an active temperature control and real-time humidity digital compensation mechanism is combined, so that the defects that a traditional sensor is easily influenced by environmental temperature and humidity and has cross interference and drift are fundamentally overcome, and the accuracy and stability of data in a full range are ensured; the equipment cabinet with the IP54 protection level guarantees long-term stable operation of internal elements in a severe industrial environment, the unique multi-step triggering process of calibration, temperature control, humidity judgment and detection ensures that measurement is automatically carried out under the optimal condition, and personal errors are reduced.

The invention discloses a synthetic method of a clarithromycin preparation promoted by ionic liquid and the clarithromycin preparation. The synthetic method comprises an etherification reaction, a silanization reaction and a methylation reaction. The etherification reaction comprises the following steps: adding erythromycin A-9-oxime into a reaction container, and adding ionic liquid [Bmim] BF4 as a reaction solvent. The silanization reaction comprises the following steps: adding 1, 1, 1, 3, 3, 3-hexamethyl disilazane and imidazole into a reaction container containing an etherification reaction result feed liquid of the [Bmim] BF4 reaction solvent. The methylation reaction comprises the step of adding methyl bromide and potassium hydroxide into a reaction container containing silanization reaction result feed liquid of the [Bmim] BF4 reaction solvent. The three-step reaction of etherification, silanization and methylation is carried out in the same reactor, and products in all steps do not need to be separated, so that a continuous process is realized. The ionic liquid as a reaction solvent is non-volatile and non-flammable, and is an important path for realizing green synthesis and clean production.

The present invention relates to an insulating flame-retardant automatically fire-extinguishing patch and a preparation method therefor. The insulating flame-retardant fire-extinguishing patch comprises a bottom film, an adhesive layer and an insulating flame-retardant layer, wherein the insulating flame-retardant layer comprises: 20-60 parts of perfluoro-2-methyl-3-pentanone microcapsules, 20-30 parts of polydimethylsiloxane, 0.1-5 parts of magnesium hydroxide, 0.1-5 parts of triphenyl phosphate, 0.5-5 parts of tributyl phosphate, 0.1-5 parts of tris(2-ethylhexyl)phosphate, 0.2-5 parts of tris(2,3-dichloropropyl)phosphate, 0.2-5 parts of a tetrabromobisphenol A epoxy resin, 0.5-3 parts of antimony trioxide, 0.1-5 parts of a borate, 0.1-5 parts of dibromochloromethane, and 0.1-5 parts of trichlorobromomethane. The insulating flame-retardant fire-extinguishing patch of the present invention is easy to install, does not require maintenance, actively extinguishes a fire in the incipient stage, can achieve the effect of repeated fire extinguishing and effectively prevent reignition and fire expansion, and is safe, green and environmentally friendly.

The invention discloses a 3-trifluoroalkyl quinoxaline-2 (1H)-ketone compound and a preparation method thereof, and relates to the technical field of organic synthesis. The invention provides a method for preparing a 3-trifluoroalkyl quinoxaline-2 (1H)-ketone compound by taking bromotrifluoromethane as a trifluoromethyl reagent through three components of bromotrifluoromethane, 1-methylquinoxaline-2 (1H)-ketone and olefin by a one-pot method in one step under the action of visible light induction and amidine organic alkali. According to the preparation method provided by the invention, the derivatives of ibuprofen and naproxen are synthesized for the first time. The preparation method disclosed by the invention has the characteristics of cheap and easily available raw materials, no need of adding a noble metal photosensitizer, simplicity in operation, mild reaction conditions, greenness, safety, excellent reaction yield and the like.

The application discloses a kind of anhydrous liquid for low-dimensional material anhydrous wet transfer and its application, anhydrous liquid includes 60% to 100% component A and 0 to 40% component B by mass percentage, component A includes one or more of tribromomethane, formamide, phenol, glycerol, methylpyrrolidone, quinoline, component B includes one or more of acetone, ethanol, isopropanol, anisole, chloroform, toluene.Formation support layer on the surface of low-dimensional material on substrate, after separation from substrate, transfer to anhydrous liquid protected by inert gas atmosphere, with target substrate from anhydrous liquid, remove support layer to realize the transfer of low-dimensional material.Widen the scope of application of wet transfer, there is no limit to substrate material, especially suitable for surface easily with water or oxygen adsorption, dissolution or reaction material, realize the preparation of low-dimensional material high mobility field effect transistor, high quality van der waals heterojunction longitudinal diode, lay the foundation for the development of high-frequency, high-speed electronic devices and circuits.