62results about How to "Avoid high temperature reaction" patented technology

The invention discloses a method for synthesizing 4-n-butylresorcinol by a microchannel reaction, belonging to the technical field of synthesis of cosmetic intermediates. The method comprises the following steps: dissolving 4-n-butyrylresorcinol in an organic solvent, adding a sodium borohydride reducing agent, and carrying out a reaction at room temperature; then feeding a reaction product into apreheating module, preheating the reaction product to 60-90 DEG C and using the preheated reaction product as a material 1; preheating a Raney nickel / organic solvent turbid liquid in the preheating module to 60-90 DEG C and using the preheated Raney nickel / organic solvent turbid liquid as a material 2; and feeding the two materials to a reaction module for a reaction so as to obtain 4-n-butylresorcinol. The method of the invention has the following advantages: the catalyst used in the method is low in cost; reaction conditions are mild; hydrogen can be slowly released for reduction; operationis relatively simple and safe; and yield is as high as 96%.

The invention relates to a metal hydride, concretely belonging to an aluminum lithium hydride making method, and its character: it adopts soluble aluminum salt and lithium salt as raw materials, and adds precipitator in water solution to coprecipitate Al3+ and Li+ ions; makes drying and high-temperature decomposition processing on the deposit to obtain an oxide; makes hydrogenation reduction on the oxide so as to obtain an aluminum-lithium mixed simple substance, and hydrogenates the mixed simple substance at normal temperature and normal pressure to obtain aluminum lithium hydride. It has low temperature in preparing course, operated at normal pressure, not only reduces energy consumption and eliminates potential danger but also the raw materials are easy to obtain and the technique is simple, and provides a new clean producing technique on friendly terms with environment for preparing aluminum lithium hydride.

The invention discloses a preparation method of a high-temperature-resistant ceramic coating on the inner wall of a small-caliber special-shaped metal pipe. The method is mainly used for preparing the coating on the inner wall of a pipe fitting with pipe diameter of less than 15mm, length of less than 500mm and irregular shape. The main preparation process is as follows: 1) preparing paint: the paint contains a silicate adhesive, a high temperature-resistant ceramic material, a solvent and an organic additive; 2) preparing the coating: the preparation of the coating adopts a grouting method, and in order to ensure the uniformity of the developed coating, a grouting device and a coat homogenization device are self-designed; and 3) drying and sealing treatment of the coating: the drying and thermal treatment are performed on the coating under a stipulated system, and then a self-made hole sealing agent is adopted for performing hole sealing treatment on the prepared ceramic high-temperature-resistant coating. The uniform and dense coating capable of working in a high temperature environment of 1200 DEG C is finally obtained.

The invention relates to a synthetic method for an allyl polyether-type high efficiency water reducing agent, belonging to the field of water reducing agent. The synthetic method utilizes allyl polyoxyethylene ether monomer, maleic-anhydride, and a mixture with one or more of (methyl) sodium allylsulfonate, 2-acryl amide-2-methylpropanesulfonic acid, itaconic acid, acrylic acid and acrylamide forobtaining polyether-type high efficiency water reducing agent by initiating one-step polymerization through inorganic peroxides in water solution system, the final structure of the water reducing agent comprises no ester bond, carboxyl, amide, sulfonic group and other functional groups. The synthetic method for an allyl polyether-type high efficiency water reducing agent has the advantages of having applicability for various concrete constructions; having simple and easy process control and non-pollution; resolving the disadvantages of lower polymerization activity of allyl polyether monomer,and resolving the ubiquitous low temperature crystallization problem of allyl polyether-type high performance water reducing agent; and realizing obtaining higher dispersity and preserving degree in low-dosage, particularly, having good dispersion performance on the condition of extremely low water cement ratio.

The invention discloses a method for preparing white carbon black with the high specific surface area from fluorosilicate. The method comprises steps as follows: firstly, an additive containing an alcoholic hydroxyl group is added to water, fluorosilicate is added to the aqueous solution, ammonia water is dropwise added after even stirring, and the solution reacts continuously; after the reaction, white carbon black with the high specific surface area is obtained through aging, filtration, washing and drying. The operation process is simple, the yield is up to 98% or higher, energy consumption is low, the BET specific surface area of the prepared white carbon black meets the HG / T 3061-2009 class-A standard, and the white activated black can be applied to multiple industries such as rubber, agricultural chemistry, papermaking and the like and has wide application prospect.

The invention discloses a polybenzoxazine aerogel heat thermal insulation material and a preparation method thereof. The polybenzoxazine aerogel heat thermal insulation material is characterized in that a bisphenol A benzoxazine monomer is used as a base raw material, polybenzoxazine is obtained by adopting acid-catalysed ring opening polymerization, and the polybenzoxazine comprises three structures corresponding to a structural formula 1. According to the preparation method, a sol-gel method is adopted; acid catalysis ring opening polymerization is carried out at the normal temperature to obtain gel with a three-dimensional network structure; then the gel is subjected to aging, solvent replacement, CO2 supercritical drying and programmed warming and heat preservation processing to obtainthe polybenzoxazine aerogel heat thermal insulation material. The material disclosed by the invention has excellent performance of low moisture absorption, high intensity, flame retardance, low density, low thermal conductivity and the like; the preparation method is simple in process; prices of raw materials are low; low-temperature ring opening polymerization avoids a high-temperature reaction;the polybenzoxazine aerogel heat thermal insulation material and the preparation method thereof have low requirements for the environment, are short in time consumption in the overall process flow and are suitable for industrial production.

The invention discloses a synthesis method of ketamine. The synthesis method comprises the following steps: (i) oxidizing and rearranging 2-chlorophenyl cyclopentyl ketone by using an oxidizing agentto generate 2-(2-chlorophenyl)-2-hydroxycyclohexyl ketone, wherein the reaction temperature is 10-80 DEG C; (ii) condensing 2-(2-chlorphenyl)-2-hydroxy cyclohexyl ketone and a sulfonylation reagent ina solvent to form sulfonate, ie., the ketamine intermediate compound is obtained, wherein the reaction temperature is 30-60 DEG C; and (iii) reacting the ketamine intermediate compound with a methylamine reagent to generate ketamine. The invention also discloses a synthetic method of norketamine. The method comprises the steps (i) and (ii), and further comprises the step (iv) of reacting the ketamine intermediate compound with an amination reagent to generate the norketamine. The method is simple, mild in reaction condition, simple and convenient to operate, low in raw material cost and suitable for industrial mass production, and a high-temperature reaction at 180 DEG C is avoided.

A preparation method of difenoconazole nitrate, comprising the following steps: 2-(bromomethyl)-2-(2-chloro-4-(4-chlorophenoxy)phenyl)-4-methyl Base-1,3-dioxolane and 1H-1,2,4-triazole carry out microwave reaction in the presence of acid-binding agent, catalyst and solvent; obtain the difenoconazole crude product dissolution after distillation; The crude product of difenoconazole is dissolved, and nitric acid is added to form a salt; after filtering and drying, the finished product of difenoconazole nitrate is obtained. The invention has milder reaction conditions for preparing difenoconazole nitrate, shorter reaction time, less solvent consumption, simple steps, environmental protection, suitability for industrialized production, and high yield and content of the final product.

The invention discloses a method for preparing N-substituted-1,2,3,6-tetrahydropyridine, which belongs to the technical field of organic chemistry. Using N-substituted-4-piperidinol as raw material, reacting with triphenylphosphine and azodicarboxylate to convert alcoholic hydroxyl group into alkenyl group to obtain N-substituted-1,2,3,6-tetrahydropyridine. The method is easy to obtain raw materials, easy to operate, and high in product purity, avoids the need for high temperature conditions and the use of highly toxic chemicals in previous methods, and has potential route advantages.

The invention belongs to the technical field of chemical synthesis and provides a method for preparing a baloxavir intermediate. The method of the present invention uses cheap and easy-to-get 3-hydroxyl-2-(hydroxymethyl)-4H-pyran-4-ketone (compound of formula I) as starting material, through TEMPO oxidation, benzyl protection, hydrolysis reaction, The intermediate compound of formula baloxavir——3-benzyloxy-4-oxo-4H-pyran-2-carboxylic acid was obtained. The method of the invention avoids the use of highly toxic chemicals such as methylsulfonyl chloride and selenium dioxide, and the reaction reagents are all common materials. In each step of the method of the invention, the temperature is controlled below 60 DEG C, high temperature reaction is avoided, and the safety factor is high. The method of the invention has short synthesis route, short reaction steps, simple operation, common and easy-to-purchase reagents, low price, and is suitable for industrial production.