213 results about "Steric effects" patented technology

The invention relates to cationic asphalt emulsifier and preparation method and application thereof. The main agent of the cationic asphalt emulsifier is prepared through the reaction of quaternarization reagent and intermediate at molar ratio of 0.5-3:1, wherein the intermediate is produced in the reaction of organic acid mixture and organic amine at molar ratio of 1: 1-3. The adjuvant agent of the cationic asphalt emulsifier is the combination of, based on the main agent by weight, 0.1-2.5% of nonionic surfactant and 0.1-2.5% of modifier. The organic acid mixture is the mixture of linear, branched or naphthene-containing organic acid with small relative pace steric effect and organic acid with big relative space steric effect at molar ratio of 1: 3- 3: 1. The quaternarization reagent is epichlorohydrin, hydrochloric acid, chloromethane, dimethyl sulfate or chloroacetic acid. The modifier is one or more of aluminum sulfate, ammonium chloride and calcium chloride and the nonionic surfactant is fatty alcohol-polyoxyethylene ether. The emulsifier has no bad effects to the property of the asphalt, has wide application range and can satisfy different construction conditions.

The invention belongs to the technical field of removal, purification and entrapment of heavy metal ions in a water body, and in particular relates to an ethylenediamine-based heavy metal chelating agent and a preparation method thereof. The ethylenediamine-based heavy metal chelating agent is prepared by directly reacting ethylenediamine, carbon disulfide and solid alkali in absolute ethyl alcohol or a mixed solvent consisting of absolute ethyl alcohol and diethyl ether in a certain volume ratio. The method overcomes the defect of steric effect of polymer chains when the conventional polymeric chelating agent chelates the heavy metal ions, and also overcomes the defect that floccules have excessive negative charge to obstruct the further growth of the floccules because of mismatched space of chelation groups of small molecules with multiple functional groups. The product is solid powder, has high stability and is convenient to store and transport. The method has the advantages of simple synthetic process, mild reaction conditions, easy operation and control, high reaction speed, high efficiency, recyclable solvent, high utilization rate of raw materials, less discharge of three wastes, environmental-friendly technical process, conventional equipment and easy industrial production.

The invention provides a carrier-linked prodrugs, wherein the biologically active moieties comprise at least one carboxylic acid and wherein the linkage between the drug moiety and linker is in the form of an ester wherein the hydroxyl group required for ester formation is provided by the linker moiety and the carboxyl group required for ester formation is provided by the drug moiety. The hydroxyl group of the linker is sterically hindered by the presence of an alkyl or aryl group on the carbon directly bound to or adjacent to the carbon carrying the hydroxyl group (α-carbon). The steric effect of the alkyl or aryl group enables greater control of the rate of hydrolytic degradation of such carrier-linked prodrugs.

Disclosed is a liquid state nano antimicrobial agent of Argentine simple substance, which comprises the following constituents (by weight percent): argentic salt 2-5%, nano Argentine generating agent 0.5-5%, Argentine complexing agent 0.5-8%, and water 82-97%. In the preparation, ionic type high molecular polymer is used as the Argentine complexing agent.

The invention discloses a carbon nano tube reinforced metal matrix composite material and an in-situ preparation method thereof in the technical field of composite materials. The in-situ preparation method comprises the following steps of: firstly, coating a carbon source substance and a catalyst precursor on the surface of metal powder; secondly, generating carbon nano tubes in situ on the surface of the metal powder on the basis of a catalytic pyrolytic reaction to obtain composite powder of the carbon nano tubes and a metal; and finally, performing densification by adopting a powder metallurgy technique to obtain the carbon nano tube reinforced metal matrix composite material. In the preparation method, tiny and dispersed catalyst particles are generated in situ by bringing the steric effect of the carbon source substances such as an organic substance or a polymer and the like, and then uniformly dispersed carbon nano tubes are generated in situ on the surface of the metal powder through the catalytic pyrolytic reaction of the organic substance or the polymer.

The present invention is method of adding one kind of secondary amine and one kind of organic amine with steric effect into water or sulfolane solution of N-methyl diethanolamine to obtain the activator for removing H2S from gas mixture with or without CO2. The present invention provides two solution recipes. The recipe I for the solution suitable for removing H2S from gas mixture containing no or less organic sulfide consists of N-methyl diethanolamine 30-50 wt%, secondary amine 1-10 wt%, steric amine 1-15 wt% and water for the rest. The recipe II for the solution suitable for removing H2S from gas mixture containing organic sulfide consists of N-methyl diethanolamine 30-40 wt%, secondary amine 1-5 wt%, steric amine 1-15 wt%, water 5 wt% and sulfolane for the rest.

The present invention is method of adding diazacyclo compound and organic amine with steric effect into N-methyl diethanolamine to obtain the activator for removing CO2 from gas mixture. The present invention provides two solution recipes. The recipe I for the solution suitable for removing CO2 from gas mixture of low operation pressure consists of N-methyl diethanolamine 30-50 wt%, substituted cyclopentyl dinitride 1-10 wt% and steric amine 1-5 wt%. The recipe II the solution suitable for removing CO2 from gas mixture of high operation pressure consists of N-methyl diethanolamine 30-60 wt%, cyclohexyl dinitride 1-8 wt% and steric amine 1-15 wt%.

Novel collagen mimics are disclosed with a tripeptide unit having the formula (Xaa-Yaa-Gly)_n, where one of the positions Xaa or Yaa is a bulky, non-electron withdrawing proline derivative. By substituting a proline derivative at either the Xaa or Yaa position in the native collagen helix, the stability of the helix is increased due solely to steric effects relative to prior known collagen-related triple helices. Methods are also disclosed for making the novel collagen mimics.

The invention provides a silica gel chromatographic packing as well as a preparation method and application thereof. The silica gel chromatographic packing is prepared from silica gel and organosilanewhich is bound to the surface of the silica gel; and the organosilane is prepared from aminopropyl silane and other silanes, wherein the aminopropyl silane is introduced into alkyl groups with the space steric effect. For the silica gel chromatographic packing provided by the invention, by introducing an organic-inorganic hybrid structure and the alkyl groups with the space steric effect, the stability of the silica gel chromatographic packing is effectively improved, and the silica gel chromatographic packing can enable lactose to have very excellent peak pattern, relatively high column efficiency and stable peak area when being used for lactose separation. In addition, the preparation method of the silica gel chromatographic packing has the advantages of simpleness, good stability, goodreproducibility, easiness in scale production and the like.

The present invention belongs to the field of nanometer material producing technology. Modified nanometer and subnanometer class superfine zinc oxide powder is produced with zinc oxide in the ammonia distillation process through adding surface modifier, or superdispersing polymer, or amphoteric structure coupling agent or other modifying solvent, and using the proper modifying process specification and method. The present invention utilizes the space steric effect to control the particles size and obtain the modified superfine zinc oxide with high dispersivity and powerful functions. The modified superfine zinc oxide powder may be used widely in rubber, ceramic, textile and daily-use chemical industries.

The invention discloses a temperature-control shape memory plugging agent and a preparation method thereof. The plugging agent is a shape memory particle; the shape memory particle comprises: hollow high-elasticity foam sponge and a temperature-sensitive type shape memory polymer coated on the hollow high-elasticity foam sponge, wherein the content of the temperature-sensitive type shape memory polymer is 20 to 99.99 weight percent of the shape memory particle; and the grain diameter of the shape memory particle is less than or equal to 8mm. The preparation method comprises the following steps: crushing, heating and melting the temperature-sensitive type shape memory polymer; uniformly coating the uncompressed hollow high-elasticity foam sponge with a temperature-sensitive type shape memory polymer hot melt solution; compressing to prepare a compressed flake; and cooling to room temperature, and cutting and granulating. According to the temperature-control shape memory plugging agent,an organic hollow high-elasticity foam sponge compound structure is adopted, and the temperature-sensitive type shape memory polymer is used for bonding and granulating. The temperature-control shapememory plugging agent is added into well cementation cement slurry or drilling mud and is stimulated by a suitable downhole temperature rising environment and the volume is expanded for a plurality oftimes; and a volume steric effect is utilized to realize the aim of plugging rock fractures.

The invention discloses a nano metal catalyst and a preparation method and an application thereof. The nano metal catalyst consists of nano Pd catalyst particles, carrier of nano Pd catalyst and a crosslink polymer coat which is wrapped on the surface of the nano Pd catalyst. The preparation method of the nano metal catalyst comprises the following steps: in the inert atmosphere, reaction monomer and comonomer are undertaken the copolymerization with the nano Pd catalyst loaded by the carrier to obtain the product. The reaction of the 2,4-dimethyl-1,3-pentylene and the propenol in the catalyzing supercritical carbon dioxide medium has high selectivity and reaction activity. The method has simple preparation process, and the metal catalyst is stable; and after the reaction is ended, the catalyst can be separated from the product through the centrifugal to be repeatedly used. By adequately integrating the steric effect of the polymer coat and the particular performance of the supercritical carbon dioxide, the nano metal catalyst has promising application prospect in the catalyzing reaction.

The invention discloses a preparation method of a conjugated three-dimensional porphyrin-based covalent organic framework material. The preparation method comprises the following steps: taking 3,3', 5,5'-tetra (4-formylphenyl) hexamethylbiphenyl (TFBM) and a series of porphyrin derivatives as raw materials, o-dichlorobenzene and n-butanol as solvents and acetic acid as a catalyst, and carrying outsolvothermal reaction for several days; after the reaction is finished, sequentially using DMF and THF for suction filtration and washing, carrying out soxhlet extraction for 24 hours, and carrying out vacuum drying to obtain purple black powder, namely the target product. For the first time, tetrahedral tetraaldehyde based on steric hindrance effect is used as a building block, so that the material has a fully conjugated three-dimensional skeleton structure, good thermal stability and chemical stability, and porphyrin units facing three-dimensional pore channels are used as single active catalytic sites, so that the material shows good application prospects in the field of bionic catalysis.

The invention belongs to the field of heavy metal pollution remediation in polluted environment, the invention discloses a method for improving stabilization efficiency of nanometer zero-valent iron in a heavy metal composite polluted soil. The method comprises the following steps of (1) preparing for the modified nanometer zero-valent iron; (2) stabilizing treatment of the modified nanometer zero-valent iron on the heavy metal composite polluted soil; and (3) evaluating a stabilization effect; the method is characterized in that sodium carboxymethylcellulose is adopted to modify the nanometerzero-valent iron, the agglomeration of the nanometer zero-valent iron is reduced through utilizing a steric hindrance effect and an electrostatic steric effect to increase the dispersity of the nanometer zero-valent iron and the mobility of the nanometer zero-valent iron in the soil. According to the method, the stabilizing efficiency of the modified nanometer zero-valent iron to heavy metals inthe heavy metal composite polluted soil is improved; and the method is simple to operate, high in repairing efficiency, low in repairing cost and free of secondary pollution to the environment.

The invention discloses a large-steric-hindrance flexible diimine ligand, diimine nickel and palladium complexes based on the large-steric-hindrance flexible diimine ligand and catalytic application of the diimine nickel and palladium complexes. Flexible substituent groups of different structures are introduced to the diimine ligand, and a series of diimine nickel and palladium catalysts with thespace steric-hinerance effect are obtained. The obtained catalysts have high thermostability and high activity for olefinic polymerization catalysis and can regulate and control the molecular weight and branching density of polyolefin by adjusting the length of chains of the substituent groups.

The invention discloses a ternary block macromonomer graft copolymerization high-property polycarboxylic acid water-reducing agent and a preparation method thereof. The preparation method comprises the following steps: dissolving a ternary block polyether macromonomer, a non-block polyether macromonomer and maleic anhydride into deionized water; then continuously stirring at a certain temperature, and respectively adding an initiating agent, a reducing agent and a chain transfer agent; and after the reaction is completed, regulating pH to neutrality to obtain the ternary copolymerization high-property polycarboxylic acid water-reducing agent. The water-reducing agent disclosed by the invention can enable the concrete to achieve higher flowing property under the condition of lower water cement ratio; because epoxy propane contained in the ternary block polyether macromonomer has an agglomeration effect and has high space steric effect, the synthesized polycarboxylic acid system water-reducing agent has more excellent dispersing retentivity, the water-reducing agent has lower air content when being used for the concrete, and the water-reducing agent is a multifunctional and high-adaptability high-property water-reducing agent which integrates water reduction, slump loss resistance and low air entrainment into a whole.

The invention discloses an acrylate copolymer synthetized through simple free radical polymerization, containing an imidazole ring side group and applied to a latent epoxy curing accelerator to simultaneously toughen epoxy resin. Firstly, imidazole is grafted to a macromolecular chain, the catalytic activity of an imidazole ring can be reduced through a steric effect to achieve the latency purpose; secondly, an acrylate molecular chain participates in formation of an epoxy curing network, microphase separation is formed in an epoxy matrix, and the mechanical property of the epoxy resin is improved. The prepared imidazole latent epoxy curing accelerator having a toughening effect can improve the curing temperature of an imidazole catalyzed DGEBA/MHHPA curing system to about 180 DEG C and has good storage stability at room temperature.

The invention discloses a method for surface modification of superfine magnesium hydroxide. The method is to add a surface modifier to an aqueous solution of inorganic water-soluble magnesium salt, and slowly add it to the reaction with a precipitating agent in a stirring state. In the kettle, react at a temperature of 20°C to 100°C for 1-2 hours, and then filter, wash and dry the reaction solution to obtain the finished product. The invention utilizes the steric hindrance effect and coating effect of the surface modifier to effectively control the particle size of magnesium hydroxide, and obtains ultra-fine magnesium hydroxide with good dispersibility, strong functionality and high flame-retardant efficiency, and The process is simple, the raw materials are easy to obtain and the cost is low, non-toxic and pollution-free, and can be widely used in polymer material industries such as plastics, rubber, building materials and unsaturated polyester.

The invention relates to the technical field of plastic shower curtains and particularly relates to a PVC (polyvinyl chloride) diamante shower curtain and a preparation method thereof. The PVC diamante shower curtain comprises the following raw materials in parts by weight: 80-120 parts of PVC resin, 40-60 parts of a plasticizer, 5-10 parts of a thermal stabilizer, 0.05-0.5 part of a flame retardant, 0.1-0.2 part of an anti-ultraviolet agent and 0.01-0.02 part of phthalocyanine blue. The preparation method for the PVC diamante shower curtain comprises the following steps: preparing raw materials, stirring at a high speed, carrying out primary plastification, carrying out secondary plastification, filtering in a hierarchical manner, calendaring molding and cooling rolling. The shower curtain disclosed by the invention is flame-resistant, insulated, alkaline-resistant, acid-resistant, waterproof, corrosion-resistant, tensile-resistant, ageing-resistant, antistatic, clear in grain pattern, and good in 3D (three dimensional) steric effect. And the preparation method of the PVC diamante shower curtain is simple in process, convenient to operate and control, stable in quality, high in production efficiency and capable of being applied to large-scale industrial production.

The invention discloses an aromatic diamine compound containing aryl phosphine groups, a prepration method and an application thereof. The structural general formula of the compound is shown in a formula I. The compound takes 3,5-difluoro-bromobenzene and diphenylphosphinic chloride as raw materials, firstly prepares 3,5-difluorophenyl diphenyl phosphine oxide by Grignard reaction and then continuously reacts with 3-aminophenol for preparation. The compound has smaller steric effect and has great value for improving the heat resistance performance of atomic oxygen resistant polyimide thin film materials and improving the visible light transparency. In addition, polyimide phosphine-containing polymer materials prepared by utilizing the phosphine-containing aromatic diamine compound have good atomic oxygen resistance performance, higher glass transition temperature and better visible light transparency, thereby being capable of being applied in the manufacturing of satellites and other aircraft parts in the LEO environment.

The invention belongs to the technical field of fuel cells, and particularly relates to a high alkali resistance polyphenyl ether anion exchange membrane and a preparing method thereof. The preparing method comprises the steps of conducting a bromination reaction to replace methyl hydrogen atoms in the polyphenyl ether and obtaining brooethyl polyphenyl ether; conducting reaction between imidazole solution and the brooethyl polyphenyl ether so as to make imidazole replace bromine atom and obtaining imidazole functionalization polyphenyl ether; synthesizing bisphenolA and 4,4'-difluorodiphenyl sulfone to obtain polysulfone solution, conducting stem grafting of the polysulfone to the imidazole through acylation copolymerization, and finally obtaining the high alkali resistance polyphenyl ether anion exchange membrane through a gel and gelatin melting process. Due to the fact that substituent group in the imidazole and steric effect of the polysulfone can well surround positive ions, attacking of OH- under an alkaline condition is hindered, so that degradation of a membrane is hindered. Besides, the high alkali resistance polyphenyl ether anion exchange membrane has a good mechanical property and a high alkaline resistance property.

The invention provides a nanometer antibody ebo7c2 for neutralizing Ebola viruses and application of the nanometer antibody to preparing medicines for preventing or treating Ebola virus infection. Amino acid sequences of the nanometer antibody are shown as SEQ ID NO:1, and nucleotide sequences for genes for encoding the nanometer antibody ebo7c2 are shown as SEQ ID NO:2. The nanometer antibody and the application have the advantages that CH2 structural domains m01s of human antibodies IgG1 are used as skeletons of the nanometer antibody, and amino acid of the nanometer antibody is different from amino acid sequences of the CH2 structural domains m01s in three loop zones; the nanometer antibody ebo7c2 can be bound with envelope proteins of the Ebola viruses; the nanometer antibody ebo7c2 has small molecular weights and is excellent in tissue permeability and ability of being bound with antigen epitopes with steric hindrance effects; the nanometer antibody is provided with the m01s skeletons and can be bound with FcRn, and the plasma half-life of the nanometer antibody can possibly reach 10 hours; the nanometer antibody ebo7c2 can be expressed in prokaryotic expression systems and is low in production cost and short in cycle.

A process concerned with aglycon-anthoxanthin bio-conversion and purification is carried out by: dissolving anthoxanthin, regulating pH and temperature, adding enzyme A, B, C sequentially and acting a period respectively, concentrating, separating, adsorbing with macro-porous resin column and adsorbing, and concentrating and drying to obtain final product. The process has advantages such as moderate reaction conditions, less by-products and environment pollution, with higher value and without steric effect.

The invention provides a solid catalyst component for olefin polymerization, which comprises Mg, Ti, halogen and electron donor, wherein the electron donor is selected from at least one of cyclosubstituted ether acid ester compounds disclosed as general formula (I) and at least one of ether, ester, ketone or amine single-function group or polyfunctional group electron donor compounds. The invention also provides a catalyst containing the solid catalyst component and application of the catalyst in olefin polymerization reaction, particularly application in propylene polymerization reaction. The specific cyclosubstituted-structure compounds contained in the solid catalyst component have a steric effect, can fix the spatial configuration of the ether and acid ester functional groups, and have active functions on participating in the formation of the catalyst activity center and enhancing the stereospecificity of the catalyst. The solid catalyst component with excellent activity can be used for obtaining the polymer product with high degree of isotacticity.