13 results about "Selective reaction" patented technology

The invention discloses a construction method and application of an SERS (Surface Enhanced Raman Scattering) sensor for detecting Mn < 7 + >. Belongs to the field of detection application, and the construction method of the SERS sensor for detecting Mn < 7 + > comprises the following steps: uniformly mixing an ABTS solution, a to-be-detected solution containing Mn < 7 + > and a silver nanoparticle solution, adding an acid solution to adjust the pH value of a reaction system, and reacting for 1-3 minutes. The SERS sensor for detecting Mn < 7 + > is applied to detection of heavy metal Mn < 7 + >. According to the method disclosed by the invention, by virtue of specific selection of the ABTS on Mn < 7 + > and addition of silver which has extremely high characteristics on SERS detection, convenient and rapid trace detection on Mn < 7 + > is realized. The selective reaction material explored by the invention is used for trace detection of heavy metal Mn < 7 + > by utilizing an SERS technology, and has important significance in application to actual life.

The application provides a metal nanomaterial toxicity prediction method and device, the method comprises the following steps: collecting related data affecting the toxicity of the metal nanomaterial, wherein the related data comprises the physical and chemical properties of the metal nanomaterial, the interaction mode between the metal nanomaterial and organisms, the influence data of external environmental factors on the metal nanomaterial, and the selective reaction data of the metal nanomaterial between different organisms; screening target indexes from the related data and calculating the weights of the target indexes; inputting the target indexes and the weights corresponding to each target index into a pre-trained toxicity prediction model to obtain a metal nanomaterial toxicity prediction result. It can be seen that the application considers multiple dimensions and calculates the weights of the indexes, the indexes considered are more comprehensive, and the index weights can better reflect the influence degree of each index on the toxicity of the metal nanomaterial, thereby improving the accuracy of the model toxicity prediction.

The invention relates to the technical field of medicine synthesis, and particularly discloses a preparation method of a cefdil intermediate. According to the invention, trichloroisocyanuric acid (TCCA) is taken as a green chlorination reagent, and reaction solvent and temperature are selected, so that the problem that benzene ring polychlorination side reaction and aldehyde functional group nucleophilic substitution side reaction are effectively inhibited while ortho-position high-selectivity mono-chlorination of phenolic hydroxyl is realized is successfully solved; and thus, the 2-chloro-3-hydroxy-4-methoxybenzaldehyde can be obtained at a high yield. On the basis, according to the scheme, subsequent anhydridation and amidation steps are further optimized, trimethylacetyl chloride is adopted to replace a traditional highly toxic activating reagent, safety and atom economy are improved, and meanwhile continuity and high efficiency of the reaction are ensured. The whole process route is reasonable in design, simple and convenient to operate and high in safety, raw materials and reagents are easy to obtain, the total yield of the reaction and the purity of the product are remarkably improved, and the method shows a wide application prospect in large-scale industrial production of the ceftidil.

This invention relates to the field of lipid biocatalysis and functional lipid preparation technology, specifically to a COF immobilized lipase system for the directed synthesis of sn-1,3-diacylglycerol, its preparation method, and its applications. This invention provides a method and system for regulating the glycerol hydrolysis reaction pathway of lipases using a cooperative covalent organic framework. By introducing multiple functionally complementary and irreplaceable covalent organic framework modules in the same reaction process, it preferentially promotes the conversion of triglycerides to sn-1,3DAG; significantly inhibits the acyl migration of sn-1,3DAG to sn-1,2DAG; reduces secondary non-selective reactions of DAG; and improves the proportion and compositional stability of sn-1,3DAG at the reaction pathway level.

This invention discloses a substrate interface pretreatment method for anisotropic magnetoresistive thin film deposition, belonging to the field of pre-deposition processing technology for thin film deposition. The method includes: (1) wiping the substrate surface with dilute hydrofluoric acid; (2) placing the substrate into a deposition chamber and evacuating it to a vacuum level ≤1×10⁻⁶. ‑6 Torr; (3) Introduce a protective atmosphere and perform a stepwise heating treatment on the substrate, including at least three steps: 100 ℃, 300 ℃, and 500 ℃. Hold each step for 20 min to 30 min to allow hydrofluoric acid to remove the oxide layer in situ and activate the surface; (4) Cool down to room temperature, stop the gas supply, and evacuate. This invention uses a synergistic process of wiping with dilute hydrofluoric acid and stepwise heating in the chamber to sequentially complete the removal of physically adsorbed water, selective reaction of the oxide layer, and activation of surface polarization bonds. The average thickness of the remaining oxide layer is ≤5 nm, and the density of surface active polarization bonds is increased by more than 10 times. The entire process is carried out in situ to avoid secondary contamination and significantly enhances the adhesion and crystal quality of the subsequently deposited film.

Disclosed are methods which comprise the preparation of beta-lactones which provide for shorter reaction times with lower by-product formation. The method comprises contacting carbon monoxide with an epoxide in the presence of a carbonylation catalyst to form a reaction mixture under conditions such that the carbon monoxide distributed throughout the reaction mixture and the reaction mixture is substantially saturated with carbon monoxide. The reaction conditions and reactor designs are chosen to distribute the carbon monoxide throughout the reaction mixture and to maintain the reaction mixture as substantially saturated with carbon monoxide. Under these conditions the formation of beta-lactones over the formation of by-products is favored.

The invention discloses a blowing method for replacing Ar with CO2 for stainless steel smelting in an AOD (argon oxygen decarburization) furnace, which belongs to the technical field of ferrous metallurgy and specifically comprises the step of blowing CO2 in proportion at the initial stage, the middle stage and the end stage of decarburization, so that the CO2 accounts for 20-100% of the total blowing amount. By controlling the furnace temperature to be 1600-1750 DEG C, the FeO content in the slag to be less than or equal to 0.5%, the CO / CO2 ratio to be 2-6 and the slag system alkalinity to be 1.7-2.2, the selective reaction of CO2 and carbon is realized, so that the effects of Ar dilution, stirring and chromium protection are replaced. According to the method, argon consumption can be effectively reduced by 30%-100%, the chromium loss is kept to be smaller than or equal to 0.2%, the decarburization efficiency is improved, terminal temperature control is improved, the process stability is high, the cost advantage is remarkable, and the method is suitable for AOD smelting production of various kinds of stainless steel.

The application discloses a method for forming a wafer pad with controllable recess degree and a structure, and relates to the field of semiconductor manufacturing. The method comprises the following steps: S100, forming a barrier layer, a seed layer and first and second pillars for bonding on a wafer; S200, depositing a stop layer on the top of the first pillar, the thickness of the stop layer being equal to a target recess degree, and the total height of the stop layer and the first pillar being smaller than the height of the second pillar; S300, performing a planarization treatment on the second pillar, and judging a process endpoint by using the polishing rate difference between the stop layer and the second pillar; and S400, removing the stop layer by etching with a selective reaction gas to expose the top of the first pillar. The application pre-sets the recess space by the stop layer, effectively protects the first pillar in the planarization process, avoids the risk of excessive polishing or insufficient polishing, and realizes clear process endpoint judgment by using the polishing selectivity ratio between materials, so that the recess degree control precision, process uniformity and bonding reliability are significantly improved.

The invention discloses an in-situ micro-area beryl Rb-Sr dating correction method which comprises the following steps: 1, after a selective reaction active gas reacts with Sr, calculating an 86Sr signal by using a signal of a product, so as to improve the accuracy of a Sr element signal; 2, correcting the ratio of 87Rb / 87Sr and the ratio of 86Sr / 87Sr by adopting a glass standard substance with a uniform Rb / Sr isotope ratio; the method comprises the following steps of: drawing an inverse isochrone graph by adopting a substrate-matched beryl standard substance HJLG241 or XXG251, calculating an apparent age, calculating a substrate effect deviation coefficient according to the apparent age and a recommended age, and applying the coefficient to 86Sr / 87Sr ratio correction of an unknown sample. According to the method, accurate dating of the in-situ micro-area beryl Rb-Sr is realized, accurate dating of the laser micro-area beryl Rb-Sr is realized, and the method has the advantages of high spatial resolution, high dating success rate, short test period and the like.

The application discloses a kind of molecular generation and optimization method and device based on autonomous chemical space design, comprising: based on the user-defined molecular building block library and chemical reaction template library, construct the autonomous chemical space including reaction template selection and reactant selection action space;Chemical space autonomous design molecule generation flow network is constructed, wherein the molecular structure is defined as state, the selection reaction template and reactant are defined as action, and the molecular generation process is modeled as trajectory;In the exploration mode, trajectory sampling is carried out in the chemical space autonomous design molecule generation flow network, and molecular generation is realized by combining the molecular building block and chemical reaction template in the autonomous chemical space;In the editing mode, trajectory sampling is carried out in the chemical space autonomous design molecule generation flow network, and molecular optimization is realized by using the molecular editing reaction template library to carry out cascading structure editing on the molecule to be optimized, so that the molecular generation and accurate optimization in the autonomous chemical space are realized.

The application discloses a coal-based ethylene glycol byproduct mixed alcohol separation system and method based on selective reaction rectification, and belongs to the field of chemical separation technology. The system comprises an ester exchange reaction rectification tower, a pressurized azeotropic rectification tower, an alcoholysis reaction rectification tower, a dihydric alcohol azeotropic rectification tower and an alcohol-ester vacuum rectification tower which are connected in sequence. The core of the application is to utilize the intrinsic kinetic difference between butylene carbonate and ethylene carbonate in the alcoholysis reaction, to overcome the separation difficulty caused by the close boiling point of ethylene glycol and 1,2-butanediol by constructing a two-stage reaction rectification coupling process. By accurately controlling the alcoholysis reaction conditions, the separation effect of preferentially reacting butylene carbonate to generate 1,2-butanediol and selectively retaining ethylene carbonate is realized. The azeotrope at the top of the pressurized azeotropic rectification tower is directly used in the alcoholysis section, which significantly reduces the energy consumption of high-purity separation, and finally synchronously outputs high-purity 1,2-butanediol, ethylene carbonate, methanol and recovered ethylene glycol.

The invention discloses a coal-based ethylene glycol byproduct mixed alcohol separation system and method based on selective reactive distillation, and belongs to the technical field of chemical separation. The system comprises an ester exchange reaction rectifying tower, a pressurized azeotropic rectifying tower, an alcoholysis reaction rectifying tower, a dihydric alcohol azeotropic rectifying tower and an alcohol ester vacuum rectifying tower which are connected in sequence, the method is characterized in that the separation problem caused by the fact that boiling points of ethylene glycol and 1, 2-butanediol are close to each other is solved by constructing a two-stage reactive distillation coupling process according to the intrinsic kinetics difference of butylene carbonate and ethylene carbonate in alcoholysis reaction; through accurate control of alcoholysis reaction conditions, butylene carbonate preferentially reacts to generate 1, 2-butanediol, and ethylene carbonate selectively retains a separation effect. The azeotrope at the top of the pressurized azeotropic rectifying tower is directly used for an alcoholysis section, so that the energy consumption of high-purity separation is remarkably reduced, and finally, high-purity 1, 2-butanediol, ethylene carbonate and methanol are synchronously produced and ethylene glycol is recovered.

Provided are a biosynthesis chip and a biosynthesis device. The biosynthesis chip comprises a substrate, a plurality of electrode units and a plurality of modification structures, wherein the plurality of electrode units are located on the substrate, and are configured to provide a voltage for monomer synthesis; and the plurality of modification structures are located on the substrate, and are configured to provide an active group for the monomer synthesis. Each electrode unit corresponds to at least two modification structures, and the at least two modification structures are arranged spaced apart from each other, such that a targeted and selective reaction with a biomonomer can be carried out, thereby improving the selectivity of biosynthesis and the accuracy of biodetection. Moreover, each modification structure facilitates the provision of sufficient reaction space and resources for biosynthesis, interference and competition between reaction regions are small, the plurality of modification structures which are arranged spaced apart from each other can respond quickly, and have high biosynthesis efficiency, which is beneficial to achieving a high-throughput biosynthesis effect.