330 results about "Aldol condensation" patented technology

The invention relates to an ammonia distillation-polymerization carbonization one-step preparation method and application of a carbon-modified copper-silicon catalyst. According to the method, carbon is introduced through aldol condensation on the basis of an ammonia distillation method Cu / SiO2 catalyst, and a carbon modified Cu / Si C-x catalyst is prepared; the proper carbon content can promote dispersion of copper on the surface, increase the proportion of Cu < + > / (Cu < + > + Cu0) and remarkably increase the number of Cu < + > sites on the surface of the catalyst, so that the catalytic performance of the catalyst is improved. According to the method, the purpose of carbon modification is achieved without any template agent or acid-base etching agent, a good methyl laurate hydrogenation effect is achieved, and meanwhile the catalyst preparation process is environmentally friendly.

The invention discloses a preparation method of a multifunctional group synergistic modified aluminum silicate nanofiber membrane, which comprises the following steps: modifying aluminum silicate nanofiber by using an amino silane coupling agent to obtain aminated aluminum silicate nanofiber; grafting a polyamino compound to the surface of the aminated aluminum silicate nanofiber by utilizing the cross-linking effect of 1, 3-dichloropropanol through a substitution reaction of amino and chlorine, so as to obtain a multifunctional aluminum silicate nanofiber; 2-butenal is modified on the surface of the multi-functionalized aluminum silicate nanofiber by utilizing an ammonia-aldehyde condensation reaction, so that the multi-functionalized aluminum silicate nanofiber rich in double bonds is obtained; carrying out cross-linking polymerization by taking itaconic acid as a monomer and the multi-functional aluminum silicate nanofiber rich in double bonds as a cross-linking agent, then carrying out suction filtration to form a membrane, and drying to obtain the multi-functional synergistic modified aluminum silicate nanofiber membrane with the gram weight not exceeding 15g / m < 2 >. According to the invention, high-efficiency adsorption of heavy metals is realized, and the problem that aluminum silicate nanofibers are not easy to recover is solved.

The invention discloses a degradable armed acetal epoxy monomer and a preparation method thereof, the acetal epoxy monomer has the following molecular structure general formula: # imgabs0 #, in the formula, R1, R2, R3 and R4 are independently selected from one of hydrogen, methoxyl and ethyoxyl. The degradable acetal epoxy monomer is prepared through the aldol condensation reaction, the thermosetting epoxy resin prepared from the epoxy monomer and the curing agent can be rapidly degraded under the normal-pressure, mild and specific conditions, and huge economic and environmental advantages are achieved for recycling and reusing of the thermosetting resin. When the prepared degradable epoxy resin is used in thermosetting epoxy resin, under the degradation condition provided by the invention, a thermosetting epoxy resin matrix is degraded into alcohol and aldehyde with relatively small molecular weight, the mixture can be dissolved in an organic solvent, and a degradation product can be extracted through simple separation, so that the purpose of recovering the resin is achieved.

The invention relates to a preparation method of a high-lithium-affinity vinylene covalent organic framework material serving as a lithium metal negative electrode interface protective layer. The method comprises the following steps: firstly, by utilizing a simple hydrothermal synthesis method, taking 1, 3, 5-trimethyl-2, 4, 6-triazine (TMT) and 2, 2-bipyridine-5, 5-diformaldehyde (BPY) as monomers, and carrying out Aldol condensation reaction to synthesize a covalent organic framework material connected by a vinylene bond, which is named as viCOF-bpy; the electrochemical performance of the material is verified by modifying the surface of a copper pole piece with the viCOF-bpy material and then assembling a battery. The lithium-loving group on the material skeleton can promote the migration of lithium ions, and the vinylidene has very strong chemical stability, so that the electrochemical performance of the lithium metal battery can be effectively improved.

The invention belongs to the technical field of high-valued utilization of biomass, and particularly relates to a production process for preparing hydrocarbon-rich bio-jet fuel through biomass staged pyrolysis coupling aldol condensation hydroconversion. According to the production process for preparing the hydrocarbon-rich bio-jet fuel by coupling biomass grading pyrolysis with aldol condensation hydroconversion, a grading pyrolysis technology is adopted, different temperature intervals are set according to pyrolysis characteristics of three major components of biomass, and pyrolysis steam with relatively enriched component content is collected step by step. The method effectively reduces the complexity of the bio-oil component, selectively prepares the pyrolysis steam rich in aldehyde and ketone and easy in aldehyde and ketonization through process regulation and control, effectively separates the pyrolysis component not easy in aldehyde and ketonization, obviously improves the yield of hydrocarbon compounds and the selectivity of the hydrocarbon compounds in graded pyrolysis of the bio-oil, and lays a foundation for subsequent directional conversion and product separation.

The invention discloses a high-temperature proton exchange membrane based on basic group grafted polyvinyl alcohol and a preparation method of the high-temperature proton exchange membrane. According to the method, polyvinyl alcohol serves as a base material, three compounds with basic groups are grafted to a polyvinyl alcohol side chain through aldol condensation reaction, crosslinking is conducted, and the polyvinyl alcohol membrane material based on basic group grafting is obtained and specifically comprises the steps that a, a polyvinyl alcohol solution is prepared; (b) adding imidazole formaldehyde or pyridylaldehyde or halogenated benzaldehyde into a polyvinyl alcohol solution, and carrying out reflux reaction by taking an HCl solution as a catalyst to prepare a graft polymer; (c) preparing the graft polymer into a graft film; (d) soaking the grafted membrane in a glutaraldehyde solution for crosslinking, and preparing a membrane material by adopting a solution casting method; and (e) carrying out phosphoric acid doping on the membrane material. The preparation cost of the membrane material is low, the reaction condition is mild, and the membrane material has a more compact or more compact structure, is transparent, uniform and compact, and has good conductivity and mechanical properties.

The invention discloses a long-acting environment-friendly flame-retardant anti-static rubber pad and a preparation method thereof, and relates to the technical field of rubber pads. The long-acting environment-friendly flame-retardant anti-static rubber pad prepared by the application comprises the static conductive layer at the bottom layer and the static dissipation layer attached to one surface of the static conductive layer. The static dissipation layer comprises modified nitrile rubber, acrylate resin and a first auxiliary agent; and the static conductive layer comprises modified nitrile rubber, butadiene styrene rubber, polyurethane resin and a second auxiliary agent. Wherein the modified nitrile rubber is obtained by reacting a Grignard reagent RMgBr with cyano groups in nitrile rubber, converting the cyano groups into carbonyl groups, and introducing a phosphorus-containing organic compound into the nitrile rubber by utilizing aldol condensation. The rubber pad prepared from the modified nitrile rubber is excellent in anti-static performance, has flame retardance, is long-acting and environment-friendly, and has a wide application prospect.

The present invention discloses a catalyst for aldol condensation reaction, its preparation and application, specifically relating to a method for preparing a catalyst for aldol condensation reaction using biomass-based SiO2 and using the catalyst to catalyze the preparation of methyl methacrylate from a mixed solution (or mixed aqueous solution) of formaldehyde and methyl propionate; the loading amount of the active metal on the catalyst is 1-10 wt%, and the total loading amount of the promoter is 0.5-5 wt%. The catalyst provided by the present invention has excellent water resistance and stability. The catalytic reaction is carried out in a fixed-bed reactor, and the carrier gas is an oxygen-containing inert atmosphere. The raw material formaldehyde in the reaction system can be obtained from methanol, and both methanol and the carrier SiO2 can be derived from biomass. Thus, under the background of aiming at "dual carbon" and popularizing green consumption, the high-value utilization of biomass resources is realized, and further the innovation of green and low-carbon technologies is achieved.

The invention relates to the technical field of preparation of high-added-value chemicals through chemical catalysis of catalysts, in particular to a preparation method, a product and application of a bimetallic MOF catalyst. The preparation method comprises the following steps: uniformly mixing zircon salt, tin salt, an organic ligand and an organic solvent to obtain a mixed solution; and heating the mixed solution for reaction to obtain a reaction solution, washing, carrying out solid-liquid separation, and drying the obtained solid to obtain the bimetallic MOF catalyst. The method is easy to operate and low in cost, is close to conditions of large-scale production and application, and has important practical value. The bimetallic MOF catalyst prepared by using the method disclosed by the invention enhances the Lewis acidity of the catalyst, effectively promotes isomerization conversion from xylose to xylulose and reverse aldol condensation from xylulose to a C3 intermediate product in a cascade reaction process, and improves the selectivity of a main reaction path for preparing lactic acid from biomass; and efficient catalytic conversion from biomass to lactic acid is realized.

The invention discloses an L-threonine aldolase mutant and application of the L-threonine aldolase mutant in synthesis of L-serine. The mutant is obtained by performing single mutation on the 88th amino acid of a wild type L-threonine aldolase amino acid sequence shown as SEQ ID No.2. The invention further discloses a preparation method of the L-threonine aldolase mutant. The invention provides the L-threonine aldolase mutant with better catalytic performance, aldol condensation reaction of formaldehyde and glycine can be efficiently catalyzed to prepare L-serine under the condition of not adding a tetrahydrofolic acid precursor, the yield of the L-serine is increased to 72.3% from 56.7% before mutation, the yield is remarkably increased, and the L-threonine aldolase mutant has the advantages that the L-threonine aldolase mutant has a good application prospect. Good application prospects are shown in the synthesis of the L-serine.

The invention belongs to the field of organic synthesis, and discloses an aldol condensation reaction method and a catalyst thereof.The method comprises the steps that in the presence of a composite catalyst, a substrate 1 and a substrate 2 are subjected to an aldol condensation reaction, after the reaction is finished, an aldol condensation product is collected from reaction products, according to the method, aldol condensation reaction of fatty aldehyde or aromatic aldehyde is catalyzed by adopting the novel composite catalyst, and the method has the advantages of being mild in reaction condition, environmentally friendly, efficient and simple in post-treatment.

The invention provides a preparation method of an omariglitazone intermediate, which comprises the following steps: by taking p-halogenated benzaldehyde as a raw material, carrying out aldol condensation reaction, hydrolysis, decarboxylation, reduction, ring closing and the like to obtain an intermediate as shown in a formula 9, carrying out catalytic reaction, reduction reaction, ring closing and the like to obtain an intermediate as shown in a formula 13, and finally hydrolyzing to obtain a target product omariglitazone intermediate A. According to the invention, links of precious metal use and chiral resolution (key steps influencing cost and yield) in the prior art are avoided, and a method for synthesizing a single configuration through a chemical method is adopted, so that the yield is greatly improved, and the production cost is greatly reduced; meanwhile, a synthesis route is broken through, a target product is synthesized through cheap initial materials, and post-treatment is simpler and more controllable.

The invention discloses a preparation method and application of an aldol condensation catalyst with a Si-O-Zr framework constructed through in-situ doping. The preparation method mainly comprises preparation and application of the Si-O-Zr framework constructed through in-situ doping and the aldol condensation catalyst. Wherein the in-situ doping construction of the Si-O-Zr framework mainly utilizes the pre-hydrolysis matching of a silicon source and the hydrolysis / polycondensation rate between a zirconium source to realize the atomic-scale dispersion of the active component, a proper pore structure can be provided for the subsequent loading of the active component, the possibility of clustering of the active component is reduced, the catalytic activity is further improved, and the method is simple in preparation and low in cost. The method is suitable for subsequent large-scale industrial application.

The present invention belongs to the technical field of covalent organic frameworks, and particularly relates to a method for preparing a single-crystalline vinylidene-bridged covalent organic framework. The method for preparing a single-crystalline vinylidene-bridged covalent organic framework comprises: mixing a single-crystalline imine-linked covalent organic framework, an active monomer, a catalyst and an organic solvent until uniform, and then performing a substitution reaction, wherein the substitution reaction is one or more of an aldol condensation reaction, a Knoevenagel condensation reaction, and a Claisen-Schmidt reaction. The single-crystalline vinylidene-bridged covalent organic framework having good stability, rich active sites, high photoelectric activity and a high conjugation degree is obtained by means of a substitution reaction of the single-crystalline imine-linked covalent organic framework and the active monomer under the action of a catalyst.

The invention discloses a quenching type fluorescent probe for detecting gold ions as well as a preparation method and application of the quenching type fluorescent probe. The fluorescent probe is 2-(3-(4-(dimethylamino) phenyl) alkenyl)-6-hydroxybenzofuran-3 (2H)-ketone. The structural formula of the fluorescent probe is shown in the description. 4-(dimethylamino) cinnamyl aldehyde is used as a raw material and is subjected to aldol condensation reaction with 6-hydroxy-2H-benzofuran-3-ketone to obtain a compound 2-(3-(4-(dimethylamino) phenyl) alkenyl)-6-hydroxybenzofuran-3 (2H)-ketone, and a compound solution can emit strong near-infrared fluorescence under excitation of laser with the wavelength of 365 nm, so that the near-infrared fluorescence can be used for detecting the near-infrared fluorescence. Near-infrared fluorescence of the solution can be rapidly quenched after gold ions are added into the solution, and the near-infrared fluorescence of the solution cannot be obviously changed after other metal ions are added into the solution. Therefore, the compound can be used as a near-infrared quenching type fluorescent probe for specifically detecting gold ions, has the advantages of low detection limit (8.47 * 10 <-8 > mol / L), short response time (less than 6s) and the like, and has a very good application prospect.

The invention relates to the technical field of alcohol preparation through aldehyde hydrogenation, in particular to a butyraldehyde, valeraldehyde and 2-propyl heptanal liquid-phase hydrogenation method and device, the device comprises a liquid-phase hydrogenation reactor, butyraldehyde, valeraldehyde and PBA, the liquid-phase hydrogenation reactor comprises an inner core pipe filled with a hydrogenation catalyst and an outer annular bed, and the outer annular bed is filled with a hydrogenation catalyst. The method is characterized in that butyraldehyde, valeraldehyde and PBA generated by an aldehyde-aldehyde condensation reaction are respectively fed into a hydrogenation system, the reactions of generating 2-propyl heptanol through PBA hydrogenation, generating butanol through butyraldehyde hydrogenation and generating pentanol through valeraldehyde hydrogenation are carried out in a liquid phase, and the pressure is about 2.4 MPa. Compared with gas-phase hydrogenation in the prior art, the liquid-phase hydrogenation adopted in the method has the advantages that the energy consumption is lower; the problem of high energy consumption of gas phase hydrogenation is solved.

The invention belongs to the technical field of medicinal chemistry, and particularly discloses a chalcone derivative and a preparation method thereof.The method includes the steps that 2, 4-dihydroxy formaldehyde serves as an initial raw material, isopentenyl is introduced into 2, 4-dihydroxy benzaldehyde through a Friedel-Crafts reaction, then the 2, 4-dihydroxy benzaldehyde and heterocycle substituted formaldehyde are subjected to an aldol condensation reaction, heterocycle is introduced, a chalcone structure is formed, and the chalcone derivative is obtained. The prepared chalcone derivative has a structural formula as shown in a formula I, physicochemical properties of the chalcone derivative are studied, and the chalcone derivatives I-4, I-5, I-7, I-8, I-9, I-10, I-11, I-12 and I-14 all show relatively strong effects of inhibiting proliferation of four tumor cells (PC9, MDA-MB-231, SMMC-7721 and SGC-7901). The chalcone derivative I-4 can effectively inhibit proliferation of human lung cancer PC9 and H1975 cells, shows concentration dependence, shows good in-vivo anti-tumor activity, can induce ferroptosis of the human lung cancer PC9 and H1975 cells, and has a good application prospect of anti-cancer drugs. # imgabs0 #

The invention relates to the technical field of comprehensive utilization of biomass resources, in particular to a preparation method of a lignin-based composite mulching film. According to the method, ammonium lignosulfonate is adopted as a raw material and mixed with a sodium alginate solution, ammonium lignosulfonate-sodium alginate gel is obtained, glutaraldehyde is added into the gel, a catalytic condensation reaction is carried out under the alkaline condition, and the liquid mulching film can be obtained. According to the method, the ammonium lignosulfonate not only contains hydroxyl, but also contains ammonium, the hydroxyl and keto are subjected to aldol condensation reaction, so that a condensation product with a cross-linked spatial network is formed, in the process, the ammonium also reacts with glutaraldehyde, the spatial structure performance of the product is further enhanced, and the molecular weight of the product is increased. Finally, the obtained lignin-based composite mulching film not only has a degradation function, but also is good in tensile property and moisture retention property, can release nitrogen elements in the degradation process, and is beneficial to keeping of soil fertility.

The present invention discloses a photocatalyst for the regeneration of coenzyme NADH and a preparation method thereof, wherein the photocatalyst is a donor-π-acceptor type conjugated organic polymer, with a triazine-based ligand as an acceptor unit and a heterocyclic ligand as a donor unit, wherein the molar ratio of the triazine-based ligand to the heterocyclic ligand is 1:(1-2), the triazine-based ligand raw material selects 2,4,6-trimethyl-1,3,5-triazine, and the heterocyclic ligand raw material selects a heterocyclic diformaldehyde containing a furan or thiophene structure. The photocatalyst is prepared by a solvothermal method through a Knoevenagel aldol condensation reaction, the reaction solvent selects a mixed solvent of n-butanol and o-dichlorobenzene or a mixed solvent of mesitylene and 1,4-dioxane, and the catalyst used in the reaction selects at least one of trifluoroacetic acid, potassium hydroxide, 1,8-diazabicycloundecane-7-ene, sodium hydroxide, and cesium carbonate. The developed photocatalyst has a donor-π-acceptor type conjugated structure, and has high catalytic activity, high selectivity, good stability, and easy separation and recovery for the regeneration of coenzyme NADH.

The present disclosure relates to a method for preparing methyl methacrylate and methylacrolein from methyl propionate, the method comprising: contacting a first stream comprising methyl propionate and a formaldehyde source with a catalyst and performing an aldol condensation reaction to obtain a second stream comprising methyl methacrylate and methylacrolein; the catalyst comprises a molecular sieve with metal elements, the metal elements comprise skeleton metal elements and non-skeleton metal elements, and the molar ratio of the non-skeleton metal elements to the skeleton metal elements in the molecular sieve is less than 0.1; the skeleton metal element comprises Sn; on the basis of the total mole number of all metal elements in the molecular sieve, the content of framework tin is greater than 90 mol%; the molar ratio of the framework tin to the silicon element in the molecular sieve is (0.001-0.05): 1. According to the method disclosed by the invention, the conversion rate of methyl propionate can be effectively improved, and the selectivity of methyl methacrylate and methylacrolein is improved.

The present application relates to the technical field of alcohol aldehyde condensation reaction, and discloses an alcohol aldehyde condensation reaction method.The alcohol aldehyde condensation reaction method is carried out in an alcohol aldehyde condensation reaction device, the alcohol aldehyde condensation reaction device comprises a micro-channel alcohol aldehyde condensation reactor and an alcohol aldehyde condensation tube reactor which are connected in series; in the presence of an alkali catalyst, a reaction raw material n-butyl aldehyde is subjected to a first alcohol aldehyde condensation reaction in the micro-channel alcohol aldehyde condensation reactor to obtain a first alcohol aldehyde condensation reaction product; and the first alcohol aldehyde condensation reaction product is subjected to a second alcohol aldehyde condensation reaction in the alcohol aldehyde condensation tube reactor.The method uses a micro-channel alcohol aldehyde condensation reactor and an alcohol aldehyde condensation tube reactor to replace a full-mixing kettle reactor in the prior art to carry out alcohol aldehyde condensation reaction, so that the yield of a by-product heavy carbon alcohol can be significantly reduced, and the yield of a target product can be improved.

The invention discloses a superstrong solid base catalyst as well as a preparation method and application thereof. Mesoporous nano MgO is obtained through urea-assisted precipitation and air atmosphere calcination, then the freshly prepared mesoporous nano MgO is soaked in an alkali metal salt solution, and a series of superstrong solid base catalysts with different alkali metal loading capacities are obtained through calcination and activation. Beta-carbon glycoside ketone and an aldehyde compound raw material without alpha hydrogen are subjected to aldol condensation reaction under the promotion of the prepared superstrong solid base catalyst to obtain a carbon glycoside product with an alpha, beta-unsaturated carbonyl structure, the separation yield of the product is 90% or above, and the reaction performance is not obviously reduced after the catalyst is recycled for ten times. The method has the advantages that the method is simple in operation and low in cost, has super-strong alkaline sites, can efficiently catalyze the aldol condensation reaction of the beta-carbon glycoside ketone to obtain the target product carbon glycoside without the assistance of amine compounds to form enamine, and is simple in reaction system separation, reusable, green in process, simple to operate and suitable for industrial production.

The invention relates to the technical field of pharmaceutical chemicals, relates to metal-loaded mesoporous silica and application thereof in synthesis of cyclic acid, and particularly relates to preparation of mesoporous silica simultaneously loaded with Mg, Al and Ca and application of the mesoporous silica as a catalyst in aldol condensation reaction for preparation of cyclic acid. The metal-loaded mesoporous silica is prepared by adopting an excessive impregnation method. The metal is one or more of Mg, Al, Ca, Co and Cu. The metals are derived from their nitrates, hydrochlorides or sulfates. When the metal is a combination of Mg, Al and Ca, the corresponding concentrations of magnesium nitrate, aluminum nitrate and calcium nitrate are 3.5-6.5 g / L, 6.5-7.5 g / L and 2.4-4.0 g / L respectively. The metal-loaded silicon dioxide provided by the invention can be used as a catalyst, and especially can be used as a catalyst for aldol condensation reaction to catalyze and synthesize cyclic acid, so that the reaction cost is reduced, and the yield and purity of the product can be obviously improved.

The invention relates to the technical field of chemical synthesis, in particular to a dihydropyrazole derivative, a preparation method thereof and application of the dihydropyrazole derivative in preparation of antibacterial drugs. The dihydropyrazole derivative is prepared from corresponding raw materials through aldol condensation, Michael addition and acylation reaction, the reaction conditions are mild, the steps are simple, and the raw materials are low in cost and easy to obtain. The compound has excellent activity of resisting staphylococcus aureus, methicillin-resistant staphylococcus aureus, ampicillin-resistant staphylococcus aureus, pseudomonas aeruginosa and bacillus subtilis. The invention is of great significance to development and research of new antibacterial drugs.

The present invention relates to the technical field of organic synthesis. Provided is a method for preparing 2,6-bis(4-azidobenzylidene)-4-methylcyclohexanone, comprising the following steps: S1, subjecting 4-nitrobenzaldehyde and trimethylsilyl azide to a nucleophilic aromatic substitution reaction to obtain 4-azidobenzaldehyde; S2, subjecting 4-azidobenzaldehyde and 4-methylcyclohexanone to an aldol condensation reaction, so as to obtain 2,6-bis(4-azidobenzylidene)-4-methylcyclohexanone. The described technical solution addresses the problems in the related art where the process for synthesizing 2,6-bis(4-azidobenzylidene)-4-methylcyclohexanone has low product yield, high costs and high energy consumption, and is not conducive to large-scale industrial production.

The modified titanium silicalite molecular sieve is characterized by containing titanium, silicon, oxygen and cesium elements, the MAS NMR spectrogram of the 133Cs at least has resonance absorption peaks of-94 + / -15 ppm,-73 + / -15 ppm and-36 + / -15 ppm. The modified titanium silicalite molecular sieve can be used in aldol condensation reaction.

The invention relates to preparation and application of a high-elastic UV (ultraviolet) monomer diisooctyl itaconate. The n-butyraldehyde is used as a starting raw material, and the raw material is low in price and wide in source. The appropriate acidic ionic liquid catalyst is screened out, aldol condensation reaction and esterification reaction can be catalyzed at the same time, other solvents are not needed, after the reaction in the step (1) and the step (2) is completed in the reaction process, aftertreatment is not needed, the next-step reaction can be directly conducted, operation steps are saved, and industrialization is better facilitated.

The present invention belongs to the technical field of aviation fuel preparation, and specifically relates to a method for synthesizing thermally stable aviation kerosene from 2,5 - hexanedione. The method comprises the following steps: 1) Using 2,5 - hexanedione as a raw material and an alkali solution as a catalyst, an unsaturated ketone compound with twelve carbon atoms is obtained through an alkali - catalyzed aldol condensation reaction; 2) The unsaturated ketone compound obtained in step 1) undergoes a hydrodeoxygenation reaction under the action of a ternary mixed metal oxide catalyst to obtain a saturated cycloalkane liquid fuel with twelve carbon atoms containing alkyl decalin. The method of the present invention simplifies the current route for preparing alkyl decalin from biomass, and the intermediate products and the final product do not need to undergo a purification / distillation process; significantly reduces the production cost, the raw materials are cheap and easily available, the reaction conditions are mild, and it is suitable for large - scale industrial production.

A process for producing C10-C18 dialkyl cycloalkanes comprising : (i) subjecting a furfural compound, a furfuryl alcohol compound or a mixture of a furfural compound and a furfuryl alcohol compound to a reductive rearrangement reaction in the presence of water, hydrogen and hydrogenation catalyst comprising a supported transition metal to produce a reaction product comprising an active methylene-group containing cyclic ketone selected from cyclopentanone, substituted cyclopentanone, cyclohexanone or substituted cyclohexanone, and mixtures thereof; (ii) reacting the active methylene-group containing cyclic ketone obtained in step (i) with a furfural compound in an aldol condensation reaction in the presence of a catalyst to produce a reaction product comprising unsaturated C10-C18 oxygen-containing cyclic organic dimer and / or trimer compounds; (iii) subjecting the unsaturated C10-C18 oxygen-containing cyclic organic dimer and / or trimer compounds produced in step (ii) to a hydrogenation reaction in the presence of hydrogen and a hydrogenation catalyst in order to produce saturated C10-C18 oxygen-containing cyclic organic dimer and / or trimer compounds; and (iv) subjecting the saturated C10-C18 oxygen-containing cyclic organic dimer and / or trimer compounds produced in step (iii) to a hydrodeoxygenation step in the presence of hydrogen and a hydrodeoxygenation catalyst to produce a hydrocarbon product comprising C10-C18 dialkyl cycloalkanes, wherein the active methylene-group containing cyclic ketone is recovered from the reaction product produced in step (i) by subjecting the reaction product of step (i) to an azeotropic distillation step (ia) to produce a distillate stream comprising a major portion of the active methylene-group containing cyclic ketone and a bottom stream comprising a major portion of water and a minor portion of the active methylene-group containing cyclic ketone, wherein said distillate stream is used as feed in step (ii).

The invention discloses a preparation method of a composite nanofiltration membrane, which is characterized in that the surface of an ultrafiltration membrane is coated with natural low-cost biological materials carrageenan and sodium carboxymethyl cellulose, so that the environmental friendliness and technical feasibility in the field of water treatment are enhanced; the preparation method comprises the following steps: firstly preparing a composite membrane, then carrying out cross-linking modification on the surface of the membrane through aldol condensation reaction, and constructing a compact and stable three-dimensional network structure selection layer after cross-linking, so that the composite membrane keeps structural stability under extreme pH conditions and in an oxychlorination environment, meanwhile, the composite membrane is endowed with efficient nanofiltration performance, and the composite membrane can be practically applied to industrial chromium-containing wastewater.