163 results about "Ortho-xylene" patented technology

Adsorbents and methods for the adsorptive separation of para-xylene from a mixture containing at least one other C₈ aromatic hydrocarbon (e.g., a mixture of ortho-xylene, meta-xylene, para-xylene, and ethylbenzene) are described. Suitable binderless adsorbents (e.g., formulated with the substantial absence of an amorphous material that normally reduces selective pore volume), particularly those with a water content from about 3% to about 5.5% by weight, improve capacity and/or mass transfer. These properties are especially advantageous for improving productivity in low temperature, low cycle time adsorptive separation operations in a simulated moving bed mode.

The invention relates to a catalyst that is used in the catalytic oxidation reaction between raw materials of ortho-xylene and/or naphthalin and gas phase that contains molecular oxygen for producing phthalic anhydride, as well as a preparation method of the catalyst. The catalyst comprises an inert imperforated carrier material and a catalytic active substance layer that is coated on the carrier and contains vanadic oxide, diantimony trioxide, titanium dioxide and a cementing agent, etc. In a preparation process of the catalyst, serum is firstly prepared, viscosity of the catalytic active substance serum is controlled, the carrier is heated, the serum is sprayed onto the carrier in a barrate, and the carrier is dried by hot wind. The catalyst is used for the field of chemical industry.

The invention relates to fixed bed combined reaction equipment which mainly comprises a cylindrical shell with an end enclosure, a reaction gas inlet and a reaction gas outlet on the shell, a porous gas distributor, a porous gas collection plate, a catalyst layer and a heat exchange pipe for cooling media to transfer heat; steam headers provided with stream pressure adjusting valves form a cooling medium circular loop of which catalysts in at least one heat exchange reaction area are filled in the pipe. The fixed bed combined reaction equipment ensures that heat transfer is designed according to the requirement on the amount of the reaction heat transfer in the reaction, is used for the synthesis of methanol and dimethyl ether, methanation, F-T reaction, the preparation of phthalic anhydride by ortho-xylene oxidation and other strong-effect reaction processes, reduces the temperature difference, improves the reaction efficiency and the yield, saves energy, reduces consumption and achieves the large-sized aim.

The invention discloses reforming catalyst and the application in the preparation of para xylene reforming high selectivity and taking saturated hydrocarbon, cycloparaffinic hydrocarbon and naphtha as the raw material. The carrier of the catalyst includes mesoporous molecular sieve, antimony oxide and inorganic melt-resistant oxide, wherein, the mesoporous molecular sieve includes 0.5 wt percent to 10.0 wt percent of phosphorus pentoxide. The surfaces of the antimony oxide and the molecular sieve included in the catalyst are contacted to facilitate the strong acid position on the surface of the molecular sieve to be intoxicated, so as to lower the reaction activity center with poor selectivity, and to maintain a passage reaction site with high selectivity; meanwhile the invention adopts phosphorus pentoxide modified molecular sieve to adjust the internal surface of the molecular sieve, particularly to adjust the size of the passage of the molecular sieve, so as to further contract the size of the passage to restrain the generation of the nonideal products of ortho xylene and meta xylene, and to improve the selectivity of the ideal product para xylene.

A process for the isomerization of xylenes and the conversion of ethylbenzene to benzene and ethane using a catalyst system comprising two catalysts. The first catalyst is unselectivated and comprises: (a) an intermediate pore size zeolite, e.g., ZSM-5; (b) at least one hydrogenation component to deethylate ethylbenzene, e.g. Group VIII and/or Group VIIIB metal; and (c) an amorphous binder, said first catalyst requiring at least 50 minutes to sorb 30% of the equilibrium capacity of ortho-xylene at 120° C. and at an ortho-xylene partial pressure of 4.5±0.8 mm of mercury. The second catalyst comprises an intermediate pore size zeolite, e.g., ZSM-5, and requires less than 50 minutes to sorb 30% of the equilibrium capacity of ortho-xylene at 120° C. and at an ortho-xylene partial pressure of 4.5±0.8 mm of mercury. The amount of first catalyst present in the catalyst system is a volume greater than 55 percent based on the sum of the volumes of the first catalyst and second catalyst.

The invention discloses preparation and an application method of a polyionic liquid solid acid catalyst, and relates to a polyionic liquid solid acid catalyst for preparing diphenylethane via alkylation reaction of ortho xylene and styrene, and a preparation method of the polyionic liquid solid acid catalyst. The catalyst has a higher alkylation conversion rate, diphenylethane yield and reusability at high temperature and atmospheric pressure. The polyionic liquid catalyst is prepared by performing a hydrothermal reaction of a vinyl imidazole monomer, N,N-methylene bisacrylamide cross-linking agent, an initiator and a dispersant to form a precursor porous polymer, and adding the obtained precursor porous polymer into haloalkane and strong acid for reaction.

A process for co-production of paraxylene, metaxylene and/or orthoxylene from a hydrocarbon feedstock (1) that comprises [1] a separation stage of the feedstock in a simulated moving bed in a chromatographic column (9) that contains a number of beds of an adsorbent, interconnected in a loop, is described, whereby said column comprises an injection (3) of the feedstock, a draw-off (10) of an extract that consists of paraxylene and desorbent, an intermediate fraction (11) (extract or raffinate) that contains ethylbenzene, and a raffinate (12) that contains a mixture of metaxylene and orthoxylene that is virtually free of ethylbenzene and paraxylene and [2] a crystallization stage (27) of the metaxylene and/or orthoxylene fraction. Upstream from the adsorption zone and/or upstream from the crystallization zone, it is possible to distill the entering mixture to produce an orthoxylene-enriched fraction at the bottom and a metaxylene-enriched fraction at the top.

The present invention relates to the preparation process and use of fluoro aromatic organic tetraacid dianhydride and its derivative. The present invention prepares fluoro aromatic organic tetrahydric dianhydride and its derivative through the Grignard reaction between metal trifluoroacetate and substituted halogeno benzene to produce alpha, alpha, alpha-trifluoromethyl phenyil ketone; the condensation reaction of the alpha, alpha, alpha-trifluoromethyl phenyil ketone and one-xylene under the action of strong acid to obtain fluoro aromatic tetramethyl compound; the high temperature nitric acid oxidation or KMnO4 oxidation of the fluoro aromatic tetramethyl compound to obtain fluoro aromatic organic tetracid; and the final dewatering. Fluoro aromatic organic tetrahydric dianhydride and its derivative may be prepared into fluoro aromatic polyimide with excellent comprehensive performance through condensation with aromatic organic diamine and subsequent imination.

The invention discloses a method for measuring the content of benzene and benzene series in hot melt glue. The method comprises the following steps of: selecting benzene, methylbenzene, ethylbenzene, o-xylene, p-xylene or m-xylene as standard substances of the benzene and the benzene series, and gradually diluting to form a standard working solution by taking glyceryl triacetate as a matrix correction fluid; taking a hot melt glue sample and adding the hot melt glue sample into the matrix correction fluid, and detecting and analyzing the standard working solution and the sample by using a headspace gas chromatography mass spectrometry; and finally, drawing a standard curve and calculating a result. In the invention, a complex pretreatment process of the sample, and influences and interference caused by volatile components in the sample are eliminated. According to the method, the recovery rate ranges from 95% to 101%, the average relative standard deviation ranges from 3.04% to 4.14%, and the repeatability is good.

The invention relates to a method by utilizing all-volatility headspace gas chromatography to measure content of alkoxy, which can be used for measuring content of alkoxy groups such as methoxyl group, oxyethyl group, propxy group and the like in polymer derivatives. The measurement method comprises the steps that: a test piece containing the alkoxy is hydrolyzed by hydriodic acid by adopting adipate as catalyst under the high-temperature closed condition, the alkoxy is transformed to corresponding methyl iodide, and ortho-xylene is used as an absorbent. Because of the effect of the catalyst and the absorbent, the adequate hydrolysis reaction is promoted, toluene is then adopted as internal standard solution, the corresponding mehyl iodide is used as the standard solution, a micro-liter-level sample is placed inside a headspace bottle, and the all-volatility headspace sampling and gas chromatography is adopted. According to the peak area of the internal standard solution and the standard solution, the content of the alkoxy in the sample is calculated. The method is better than ordinary chemical titration method and gas chromatography and has the characteristics of short analysis time, simplicity in operation, high accuracy and the like.

Adsorbents and methods for the adsorptive separation of para-xylene from a mixture containing at least one other C₈ aromatic hydrocarbon (e.g., a mixture of ortho-xylene, meta-xylene, para-xylene, and ethylbenzene) are described. Suitable adsorbents comprise zeolite X having an average crystallite size of less than 1.8 microns. The adsorbents provide improved mass transfer, which is especially advantageous for improving productivity in low temperature, low cycle time adsorptive separation operations in a simulated moving bed mode.

The invention relates to an aromatic hydrocarbon alkyl transfer method for producing benzene and p-xylene, and the method is mainly used for solving the problems that in the prior art, an isomerization unit and a disproportionation unit of p-xylene just respectively process C8 aromatic hydrocarbon and toluene, and the equipment investment is large. The method comprises the following steps: a) feeding mixed xylene containing o-xylene and m-xylene and a toluene material into an aromatic hydrocarbon alkyl transfer process unit so as to generate an aromatic hydrocarbon alkyl transfer reaction under the hydrogen condition so as to generate an aromatic hydrocarbon material flow containing benzene and p-xylene after reaction; (b) successively passing the aromatic hydrocarbon material flow containing the benzene and the p-xylene through a benzene tower, a toluene tower and a xylene tower so as to separate out the benzene and the mixed xylene; and (c) feeding the mixed xylene in a absorption separation or freezing crystalline separation unit so as to generate the p-xylene, and feeding the unreacted toluene and xylene in the aromatic hydrocarbon alkyl transfer unit, wherein a composite catalyst bed layer is adopted in the aromatic hydrocarbon alkyl transfer process unit, aromatic hydrocarbon alkyl transfer reaction occurs to the upper catalyst bed layer, and toluene selectivity disproportional reaction is carried out on the lower catalyst bed layer with a shape-selective function. By using the technical scheme, the problem can be well solved; and the method can be applied to production of benzene and p-xylene.

The invention provides a method for preparing aromatic compounds by conducting hydrogenation and depolymerization on spruce lignin through the electro-catalysis technology. According to the method, electrocatalytic oxidation is conducted in a sodium hydroxide solution so that the lignin can be degraded, meanwhile, degradation intermediates in the spruce lignin are subjected to hydrogenation reduction through cooperation of electro-catalysis, that is, an electrolytic reaction tank is composed of a Pb/PbO2 electrode and a Ni electrode, a lignin alkaline solution serves as an electrolyte solution, part of chemical bonds in the lignin are subjected to oxidative cleavage by active substances (hydroxyl radical.OH or peroxy-anion radical O2<->) generated on the surface of the anode (the Pb/PbO2 electrode) through electrolysis alkaline water, the molecular weight of the lignin is effectively reduced, depolymerized compound intermediates are subjected to hydrogenation reduction by adsorption hydrogen atoms (Hads) generated on the surface of the cathode (the Ni electrode) through the electrolysis alkaline water, and finally, aromatic products including methylbenzene, ortho-xylene and m-xylene are obtained.

The invention provides a method for in-situ synthesizing a precious metal loaded ZSM-5 molecular sieve. The method is characterized by comprising the following steps of stirring and mixing an aluminum source, water, a template agent solution and a precious metal saline solution; adding a silicon source, and stirring and mixing; crystallizing a mixture in a reaction kettle to obtain a crystal substance, and cleaning and drying to obtain the precious metal loaded ZSM-5 molecular sieve. The preparation method provided by the invention is simple, a preparation process of a traditional zeolite molecular sieve loaded precious metal catalyst is simplified, the steps of roasting and H2 reducing are saved, the operation cost is reduced, and the catalytic efficiency of the prepared molecular sieve on ortho-xylene is remarkably superior to the precious metal loaded ZSM-5 molecular sieve prepared through a traditional impregnation method.

The invention relates to a high-selectivity synthesis method of 4-nitro-ortho-xylene. The 4-nitro-ortho-xylene is highly selectively synthesized from ortho-xylene (serving as a basic raw material) in the presence of a catalyst and a nitration reagent (which is nitrogen dioxide instead of nitro-sulfuric acid). The method provided by the invention comprises the following steps of: adding the ortho-xylene and the catalyst into a reactor; adding the nitrogen dioxide into the reactor, and then magnetically stirring the mixture for complete reaction; and after the reaction is ended, terminating the reaction by using a saturated sodium bicarbonate solution and carrying out extraction. By adopting the synthesis method provided by the invention, the yield and the selectivity of the reaction can be obviously improved by the catalyst added in the reaction process; and the synthesis method provided by the invention is mild in reaction condition, good in selectivity, high in yield and applicable to engineering application.

The invention relates to a preparation process of a,a,a',a'-tetrachloroortho-xylene. The preparation process comprises the following steps of: (1) undergoing a chlorination reaction, naturally cooling reaction liquid and performing suction filtration to obtain filtrate and a filter cake, wherein in the ultraviolet irradiation chlorination reaction process, the total mass of introduced chlorine gas is 2.60-2.80 times the feeding mass of ortho-xylene; at the first stage, the reaction temperature is 120-125 DEG C, and the mass of the introduced chlorine gas is one third of the total mass of chlorine gas; at the second stage, the reaction temperature is 125-130 DEG C, and the mass of the introduced chlorine gas is a half of the total mass of the chlorine gas; and at the third stage, the reaction temperature is 130-135 DEG C, and the mass of the introduced chlorine gas is one sixth of the total mass of the chlorine gas; (2) performing a depth chlorination reaction; and (3) purifying and crystallizing to obtain a target product. The preparation process has the advantages of increasing the total yield of the a,a,a',a'-tetrachloroortho-xylene and reducing the yields of trichloroortho-xylene and pentachloroortho-xylene as much as possible.

The invention discloses a method for determining coexisting impurities and trace arenes in methanol simultaneously. In the method, gas chromatography is performed on methanol, and an external standard method is used for quantitatively determining the contents of the coexisting impurities and the trace arenes in the methanol, wherein the coexisting impurities refer to methyl acetate, acetone and ethanol, the trace arenes comprise the following components: benzene, toluene, ethylbenzene, p-xylene, m-xylene, o-xylene, styrene and phenol. The coexisting components and the common arenes types in the methanol are considered in the method simultaneously, thus the simultaneous determination method for the eleven components in the methanol is established in an optimization manner. The simultaneous determination of multiple components is beneficial to saving of manpower and material resources to a great extent, acceleration of the detection speed, and accurate judgment of the polluted arenas types in methanol during storage and transportation. The method has the advantages of convenience for operation, low detection cost, accuracy, sensitivity and high efficiency.

Described herein are enhanced performance of antistatic additive compositions for hydrocarbon fuels, the compositions comprising olefin-sulfur dioxide copolymers in combination with polymeric polyamines prepared using an ortho-xylene solvent.

The invention provides a cerium oxide nano cubical material which has excellent thermal stability and can catalyze and oxidize ortho-xylene into harmless CO2 and H2O with high efficiency under a condition of low temperature and a preparation method thereof. The preparation method of the material comprises the following steps of: taking soluble cerium salt as a precursor, adding excessive sodium hydroxide as a precipitator, then transferring the excessive sodium hydroxide into a reaction kettle, keeping the temperature constant within a range of 80-120 DEG C for 8-12h, washing the obtained precipitate with deionized water, drying over night and calcining at the temperature of 350-750 DEG C in a muffle furnace to obtain a nano cerium oxide cube. The method has the advantages of simple preparation method, low price and easy acquirement of raw materials, controllable appearance of the obtained material and the like; and the prepared nano material presents favorable uniformity, monodispersity and thermal stability and can be used as a catalyst and a carrier of the catalyst. Nano cerium oxide in the invention is used as the catalyst, can directly oxidize the ortho-xylene into the CO2 and the H2O within a temperature range of 140-260 DEG C, does not generate a by-product, represents favorable low-temperature catalytic activity and has higher practical value.