1446 results about "Dehydration reaction" patented technology

The invention discloses a molecular sieve based catalyst, a preparation method and an application thereof in crylic acid preparation by lactic acid dehydration. The method comprises the following steps: processing the ZSM-5 molecular sieve in aqueous alkali, or adopting an impregnation method to support phosphate, drying, roasting and finally obtaining the modified molecular sieve based catalyst. The catalyst realizes the reaction of crylic acid preparation by lactic acid dehydration in low temperature and has the advantages of high lactic acid conversion rate and crylic acid selectivity, and long-life of catalyst, the conversion rate of lactic acid dehydration reaction is 100%, and crylic acid selectivity can reach as high as 83.9%, thus having good industrial application prospect.

The invention discloses a method for preparing 5-hydroxymethylfurfural by solid acid catalysis. The method comprises the following steps of taking lignin residue hydrolyzed by biomass as carrier raw material of solid acid; synthesizing the raw material into solid acid through a two-step way of carbonization and sulfonation, so that the waste material is recycled and the problem of disposal of pollutants is solved. In the dehydration reaction of lignin-based solid acid catalyzed fructose and glucose, the yield of 5-hydroxymethylfurfural can be respectively 84% and 68%; after the dehydration reaction, the lignin-based solid acid is easy to separate and reusable, the acid density of the solid acid can be reduced after being reused five times, and the yield of the 5-hydroxymethylfurfural is still higher than 75%. The method provided by the invention can be used for realizing emission without pollution, and is helpful for realizing environment-friendly producing process of 5-hydroxymethylfurfural.

A method preparing controlled release nitrogen in particulate fertilizers which exhibit single growing season availabilities to plants of about 80 percent or higher. The method utilizes relatively low urea and ammonia to formaldehyde mol ratios of about 1.7 urea to 0.1 ammonia to 1 formaldehyde to assure high conversions to controlled release nitrogen with low free ureas, and carefully controlled elevated temperatures, acid dehydration condensation catalyst concentrations and short dehydration reaction times of about 2-4 minutes to provide effective conversion of hydroxymethyl nitrogen compounds by dehydration condensation reaction to controlled release methylene nitrogen compounds. Quick neutralization of the dehydration catalyst in a turbulent mixing reactor minimizes the formation of undesirable methylene nitrogen polymers which are hot water insoluble and unavailable to plants in a single growing season.

Ethanol obtained from ordinary biomass resources contains many impurities other than water and these impurities themselves or their decomposition products contaminate ethylene when the ethylene is produced by a dehydration reaction, whereby the activity of metathesis catalyst is adversely affected. A method for producing propylene of the present invention is characterized in that the ethanol obtained from biomass is converted to ethylene by a dehydration reaction, the ethylene is separated from the generated water, the separated ethylene is purified by adsorption in an adsorption tower filled with an adsorbent, and then a metathesis reaction is carried out along with a raw material containing n-butene. With the present invention, propylene having biomass-derived carbon and reduced-environmental burden can be efficiently produced without lowering the catalysis activity.

The invention relates to a ZSM-5 molecular sieve modified catalyst. The ZSM-5 molecular sieve modified catalyst comprises the following porous crystal materials in molar ratio: Al2O3 to nSiO2. The invention also relates to a preparation method of the ZSM-5 molecular sieve modified catalyst, a load modified catalyst which is used for low-concentration ethanol dehydration reaction and is specifically prepared performing radical grafting and surface modification by taking a ZSM-5 molecular sieve as a carrier and, and a preparation method for preparing ethylene through dehydration of low-concentration ethanol on a fixed bed reactor. In the preparation method, the low-concentration ethanol dehydration catalyst prepared by loading a modified ZSM-5 molecular sieve has the characteristics of high catalytic activity, high selectivity, easiness in regeneration and the like. Through long-term continuous running on the fixed bed reactor, the ZSM-5 molecular sieve modified catalyst shows the low reaction temperature and low energy consumption performances when used in a low-concentration ethanol dehydration process, the ethanol conversion ratio is high, the ethylene selectivity and yield are high, and the catalyst has the advantages of being stable in activity, convenient to regenerate, stable to operate and the like.

The invention involves preparation of ZSM-5 molecular sieve modified catalysts and the technology of using said catalysts in low concentration ethanol dehydration reaction, specifically a method uses ZSM-5 molecular sieve as carrier and prepares load modified catalysts through group grafting and surface modification, and a preparation method is used for preparing ethane through low concentration alcohol dehydration on fixed bed reactor. The low concentration alcohol dehydration catalyst prepared by load modified ZSM-5 molecular sieve in the invention has characteristics of high catalytic activity, high selectivity and it is easy to regenerate. When it is operated for low concentration alcohol dehydration art through fixed-bed reactor device long time and continuously, it displays advantages of low reaction temperature, low energy consumption, high conversion rate of ethanol, high ethylene selectivity and yield, stable catalyst activity, convenient regeneration and smooth operation.

The invention provides methods for rapidly synthesizing heteroatom containing zeolites including Sn-Beta, Si-Beta, Ti-Beta, Zr-Beta and Fe-Beta. The methods for synthesizing heteroatom zeolites include using well-crystalline zeolite crystals as seeds and using a fluoride-free, caustic medium in a seeded dry-gel conversion method. The Beta zeolite catalysts made by the methods of the invention catalyze both isomerization and dehydration reactions.

The present invention relates to a novel method of using industrial dicyclopentadiene of purity of 75 percent to 85 percent to prepare modified unsaturated polyester resin. In the preparation of the resin, the industrial dicyclopentadiene separated from the saturated or unsaturated dicarbonic acid or acidic anhydride and the distilled part of mixed C5 is used as the raw material. After hydrolysis and addition reaction, the diol or polyol of appropriate amount is added. The polymerization and dehydration reaction is done with the influence of acidic catalyst. When the mixture is condensed to the designated acid value, the inhibitor and cross-linking monomer of appropriate amount are added and then stirred to prepare the product. The present invention has the advantage that the cost of resin is lower than the common type unsaturated resin. At the same time, the air-drying performance, heat resistance, volumetric shrinkage rate and other performances are all superior to the common type unsaturated polyester resin. The product can be widely used in the fields of glass steel, mold, plastic clothing, sealing, and adhesive and so on.

A method for utilizing an industrially convenient fructose source for a dehydration reaction converting a carbohydrate to a furan derivative is provided. Recovery methods also are provided. Embodiments of the methods improve upon the known methods of producing furan derivatives.

A catalytic process for converting biomass-derived carbohydrates to liquid alkanes, alkenes, and/or ethers is described. The process uses combinations of self- and crossed-aldol condensation reactions, dehydration reactions, and hydrogenation reactions, over specified metal-containing catalysts, to yield alkane, alkene, and ether products from carbohydrate reactants.

The invention discloses a high-bonding-strength and high-temperature-resisting phenolic resin modified polyurethane adhesive and a preparation method thereof. The preparation method comprises the following steps of: synthesizing modified phenolic resin, preparing polyurethane prepolymer, synthesizing modified polyurethane prepolymer, and synthesizing the modified polyurethane adhesive, wherein the step of synthesizing the modified phenolic resin is carried out by adding methoxyl dimethylbenzene monomer and phenols in phenolic resin to react under the effect of an acid catalyst, cooling the mixture, and then adding a basic catalyst, solvent and formaldehyde in the mixture for dehydration reaction under vacuum until the mixture is transparent, thus obtaining the modified phenolic resin; the step of preparing the polyurethane prepolymer is carried out by adding polyisocyanates and polyester polyol in the modified phenolic resin for reacting; the step of synthesizing the modified polyurethane prepolymer is carried out by modifying the polyurethane prepolymer through the modified phenolic resin to obtain the modified polyurethane prepolymer; and the step of synthesizing the modified polyurethane adhesive is carried out by adding water to the modified polyurethane prepolymer, and dispersing the modified polyurethane prepolymer through dispersing agent, and finally adding neutralizing agent, cross-linking agent and chain extender into the dispersed modified polyurethane prepolymer to obtain the modified aqueous polyurethane adhesive. The preparation method disclosed by the invention is simple, and improves the bonding strength and high temperature resistance of the polyurethane adhesive.

The invention discloses a sulfur-containing bis-imidazoline type carbon dioxide corrosion inhibitor and a preparation method thereof. The corrosion inhibitor comprises the following components in percentage by weight: 20-50 percent of sulfur-containing bis-imidazoline quaternary ammonium salt, 1-5 percent of nonionic surfactant, 40-70 percent of low molecular alcohol solvent and 5-10 percent of alkynol, wherein a sulfur-containing bis-imidazoline compound has a general formula of a structure which is shown in the specification; the number of carbon atoms in R of the formula is 5 or 8; the nonionic surfactant is fatty alcohol-polyoxyethylene ether or alkylphenol ethoxylate; the low molecular alcohol solvent is methanol, ethanol, isopropanol or ethylene glycol; and the alkynol is propargyl alcohol or hexynol. In the invention, the sulfur-containing bis-imidazoline compound which is generated through dehydration between dicarboxylic acid and polyamine molecule, dehydration reaction in the molecule and further reaction with the sulfur-containing compound is adopted; the molecule contains a plurality of active adsorption centers such as two diazo five-membered heterocyclic rings, a sulfur-containing group and the like; and a formed organic adsorption membrane has better protection effect on carbon steel.

The invention discloses a method for preparing isosorbide by taking supported heteropoly acid as a catalyst. Sorbitol from a biological radical is used as a raw material to prepare the isosorbide directly through dehydration reaction. The method comprises the following steps: putting the catalyst into a constant temperature section of a fixed-bed reactor; introducing a reactant sorbitol solution into a reactor, and performing reaction through a catalyst bed after gasification; and separating a mixture obtained after the reaction to obtain the isosorbide. The method has simple operation process of the reaction, low production cost and light environmental pollution; the selectivity and yield of the isosorbide reaches up to 75.2 percent and 71.4 percent respectively, and the catalyst is easy to separate and recycle; and the method is a novel method which meets industrial demands and has strong practicality.

The invention provides a method for preparing liquid alkane fuel by upgrading bio-oil in an aqueous phase catalytic mode. The method comprises the following steps of: 1) pretreating the bio-oil to obtain a water-soluble component and a water-insoluble component; 2) performing a pressurized acid hydrolysis process on a furan compound of the water-insoluble component to prepare the furan compound; 3) performing a reforming and hydrogen production reaction on the water-soluble component; 4) mixing the furan compound with a liquid-phase product separated from the step 3) to perform an aldol condensation reaction to increase carbon chains; and 5) performing a hydrogenation and dehydration reaction on an aldol condensation product to obtain liquid linear alkane. The method has the advantages that: an upgrading process, which is performed in a double-phase system, can effectively contribute to the desorption of an intermediate product from the surface of a catalyst and the mass transfer of an upgraded product, and can reduce the risk of carbon deposition on the surface of the catalyst; the quality of oil obtained by the method is high; the energy density and the energy grade of the bio-oil are improved greatly; and the liquid alkane fuel can be obtained from all kinds of bio-oil so as to partially substitute for the conventional widely-used fossil gasoline and diesel oil fuel.

The invention provides a preparation method of phosphorus-containing halogen-free environmentally-friendly flame-retardant polyester polyol. The method comprises the steps that with DOPO being starting material, firstly, the DOPO reacts with dibasic acid or dibasic acid anhydride to generate a DOPO complex intermediate; secondly, esterification dehydration reaction is performed on the generated intermediate, small-molecules polyol and dibasic acid or dibasic acid anhydride at 150 DEG C-160 DEG C; after the dehydration reaction is over, the temperature is raised to 200 DEG C-250 DEG C for transesterification, wherein the reaction time is 1 h-3 h, and in this way, the polyester polyol is obtained. The prepared polyester polyol is not conventional polyester polyol but the polyester polyol containing the phosphorus element, has the reactivity with isocyanate and can be used for permanent flame retardant modification of polyurethane products. As the phosphorus element is introduced to the polyester polyol, the polyester polyol contains phosphorus and is free of halogen, environmentally friendly and capable of inflaming retarding.

The invention relates to a method for preparing 5-hydroxymethylfurfural and furfural by adopting a biomass raw material. The method comprises the following steps: adding the biomass raw material, solvent, solid phosphate catalyst and soluble inorganic salt into a reactor to form a reaction system; carrying out the dehydration reaction for 0 to 100h under the protection of inert gases at the temperature of 20 to 400 DEG C to obtain products 5-hydroxymethylfurfural and furfural with high yield. The novel method has the advantages that the weaknesses of the prior art that the toxicity of catalyst is large, equipment is likely to corrode, the price is high, the preparation method is complicated, recycling is difficult to realize and the like can be overcome. The solid catalyst has the characteristics of high catalytic activity, high selectivity, high efficiency, environmental friendliness, less byproducts, recyclability and the like, and is easy to separate and recycle.

The invention discloses a system and method to produce furfural with agricultural wastes, which is characterized by the following: choosing two-step method; comprising hydrolysis system and dehydration distilling system; setting the hydrolysis system as N grade hydrolysis autoclave with end-to-end; proceeding continuous hydrolysis for the agricultural wastes; generating pentose solution; setting the dehydration distilling system as dehydration distilling unit and dehydration reclaiming unit; dewatering and distilling for the pentose solution with the dehydration distilling unit; getting furfural steam; setting the dehydration reclaiming unit as at least one grade dewatering reactor; further-dewatering; generating furfural steam; sending into dehydration distilling tower; distilling continuously; sending the waste water from the dehydration reclaiming unit back to dehydration system; realizing zero discharge for waste water. This invention possesses high productivity, low energy consumption and warm reacting condition, which can be used as raw material to produce alcohol.

The invention discloses an aggregation-induced emission molecule as well as a preparation method and use thereof. The aggregation-induced emission molecule has a structural formula (shown in the description), wherein when Ar1 and Ar2 are same groups, Ar2 is a group shown in the description; and when Ar2 is hydrogen, Ar1 is a group shown in the description. The preparation method comprises the steps of: starting from a group shown in the description, wherein X=br, and Y=H or X=H, and Y=Br and tetraphenyl ethylene boric acid ester, obtaining derivatives of fluorene containing toluene and triphenylamine units by utilizing an acid-induced intramolecular dehydration reaction, linking tetraphenyl ethylene to a ninth site of the fluorine in a conjugated manner by utilizing a Suzuki reaction, and finally obtaining a target compound. According to the compound disclosed by the invention, the heat stability and the aggregation-induced emission property are good, the solid fluorescence quanta of the compound are high in yield and are emitted by blue lights, and the compound can be applied to a luminescent layer material of a blue-light inorganic light emitting diode; and the reaction conditions of the preparation method are mild, and the yield is high.

The invention discloses a preparation method and application of gum rosin acid copper. The method for preparing the gum rosin acid copper comprises the following steeps: evenly mixing copper salt with alkali liquor; mixing the obtained mixture into a uniform suspension; then slowly dropping the uniform suspension into a solution consisting of rosin and solvent, wherein in the dropping process, the color of the solution is gradually changed from blue to green, and the exothermic phenomenon is produced, then timely cooling is carried out in time, and the dropping process is completed within 20 to 40 minutes; after the dropping process is completed, raising the temperature of the obtained solution to 70 to 90 DEG C, and then carrying out atmospheric dehydration reaction on the obtained solution by using a water separator (100L); and after the dehydration reaction is completed, filtering the obtained object by using standard filter papers so as to obtain a gum rosin acid copper solution of which the concentration is 20 to 50 percent, then analyzing and detecting the content of the obtained product. The application of the gum rosin acid copper is as follows: the gum rosin acid copper prepared in the invention is used together with medicaments for preventing crop diseases and pests. The invention solves the problems that the existing method for preparing the gum rosin acid copper is complicated, hard to implement and not environmental-friendly, and the application scope of the current gum rosin acid copper is narrow.

The present invention discloses a molecular sieve catalyst, a preparation method thereof and the application of the molecular sieve catalyst for preparing for ethene by dehydrating ethanol. The catalyst uses ZSM-5 molecular sieve or HZSM-5 which is obtained by acidifying the ZSM-5 as a support; oxide or salt of heteropoly acid or vanadium (V) or titanium (Ti) is used as active component; the active component is introduced into the support by a dipping method or a surface chemical reaction modifying method to be dried and calcined in a muffle furnace to obtain the molecular sieve catalyst. The catalyst is used in ethanol dehydration to prepare for the ethene and not only has high ethanol conversion rate and ethene selectivity and long service life, the maximum conversion rate of ethanol dehydration reaction can be 100 percent, and the maximum selectivity of the ethene can be 99.4 percent; but the catalyst also solves the technical problems of low airspeed, high temperature, high energy consumption, and the like, in the reaction of preparing for the ethene by dehydrating the ethanol; the catalyst is applicable to the industrial production of preparing for the ethene by dehydrating the ethanol and has the effects of improving production efficiency and saving energy source.

The invention relates to a preparation technique of isosorbide, belonging to the technical field of pharmacy. In the preparation technique, solid sorbitol is used as the raw material, a mixture of perfluoro-sulfonic acid resin and palladium on carbon is used as the catalyst, and hydrogen is used as an anti-carbonation agent to prepare the non-carbonized light-colored isosorbide reaction liquid; and low-temperature concentration and solvent crystallization are utilized to substitute the original high-temperature distillation. The preparation technique comprises the following steps: dehydration reaction, neutralization decolorization, electrodialysis desalination, water removal by concentration, extraction crystallization, freeze-drying, and quality inspection and packaging (after the product is qualified in inspection, packaging, and warehousing as the finished product). The invention can prevent carbonization and prevent the reaction liquid from becoming dark, thereby enhancing the utilization ratio of the raw material; most calcium salts are precipitated due to low solubility, and the electric conductivity of the reaction liquid is low, thereby being beneficial to subsequent extraction; and the invention overcomes the defect of high energy consumption in the high-temperature distillation technique, and the quality of the prepared isosorbide is more excellent.

The invention discloses a method for preparing a super-hydrophobic coating with a nanocrystalline cellulose/silicon dioxide (NCC/SiO2) composite template process. The method comprises the following steps: (1) treating microcrystalline cellulose (MCC) with 56% sulfuric acid; (2) performing centrifugal washing; (3) replacing water in an NCC suspension solution with ethanol; (4) grinding for later use; and (5) freezing a sample to subzero 30 DEG C and performing vacuum freeze-drying. The method has the advantages that stearic acid is taken as a modifier and can produce a dehydration reaction with surface -OH of SiO2/NCC, and stearic acid further introduces hydrophobic -CH3 groups, so that the surface energy of SiO2/NCC is reduced; and an NCC and SiO2 compound has not only the properties of a biopolymer material but also the properties of an inorganic material such as weather resistance, hardness and the like, can be used for modifying indoor and outdoor coatings, and can play a role in aspects of building floor cleaning, furniture pollution prevention and the like.

The invention discloses a preparation method of acrolein, taking biological glycerol as the raw material and the modified zeolite supported heteropolyacid as catalyst, the method prepares acrolein directly by dehydration reaction. 18 to 30 catalyst are put in the middle section of a normal pressure continuous fixed bed reactor, with the volume space velocity of 1 to 10 h<-1>; under the protection of N2, the catalyst bed raises the temperature to 180 to 540 DEG C, and the biological glycerol solvent which is added with inhibitor is put into the fixed bed reactor from a micro pump; after gasified, the glycerine solution reacts by the catalyst bed. After reaction, the product is absorbed by acetone, then is separated and purified, thus obtaining acetone. The invention adopts the alkali metal, phosphoric oxides, alkali metal compound improved catalyst as carrier to carry heteropoly acid catalyst which is green and environmental catalyst and has the advantages of high activity, regeneration property, no pollution, simple reaction, operation process, low production cost, high mole selectivity of acrolein and high conversion rate of biological glycerol.