333 results about "P-Xylene" patented technology

The invention discloses a p-methyl benzyl chloride production process and a production system thereof, p-xylene side chains and chlorine are subjected to a gas phase substitution reaction under micro negative pressure and visible light catalysis to generate crude methyl benzyl chloride and hydrogen chloride, and 99.0% methyl benzyl chloride, a small amount of benzyl dichloride and 31% hydrochloric acid are respectively generated through rectification and absorption; the device consists of four working sections of chlorination, rectification, hydrochloric acid absorption and distillation. According to the method, the defects in the prior art are overcome, on one hand, chlorine is introduced, and an aromatic ring chlorination reaction is carried out under visible light catalysis; on one hand, a supported catalyst filler is arranged at the bottom of a chlorination tower, and a zeolite molecular sieve modified by long-chain alkylsilane and supported by metal salt is used as a catalyst to catalyze chloromethylation reaction, on the other hand, the hydrophobicity of the modified catalyst is obviously enhanced, and meanwhile, the density of acidic sites is not reduced; the contact opportunity of the catalyst and a reaction substrate is greatly increased, and the catalytic efficiency of the catalyst is improved.

The invention provides a crystalline supramolecular polymer based on snap ring aromatic hydrocarbon. The polymer is obtained by self-assembling snap ring aromatic hydrocarbon (CLP) and a naphthalimide derivative (NDI-8) through a subject and an object. The crystalline supramolecular polymer (NDI-8 (at) CLPalpha) can fully utilize the synergistic effect of a plurality of weak interactions, so that the charge transfer interaction between molecules can be remarkably enhanced very easily. The crystalline supramolecular polymer constructed based on charge transfer shows excellent gasochromic performance. The p-xylene in the NDI-8-coated CLPalpha p-xylene isomer has efficient identification and detection capability, the color is changed from purple to light pink, and a wide application prospect is provided for the development of stimuli-responsive materials.

The invention relates to an aromatic hydrocarbon isomer adsorbent containing a modified X-type molecular sieve. The outer surface area of the modified X-type molecular sieve is 9.5-19m < 2 > / g, and the sum of the pore volume of mesopores and the pore volume of macropores is 6%-18% of the total pore volume. The p-xylene adsorbent comprises 88-95% by mass of a modified X-type molecular sieve, 4-11% by mass of a crystal transformation X-type molecular sieve and 1-3% by mass of a matrix. The invention also relates to a preparation method of the adsorbent and application of the adsorbent in adsorption separation of p-xylene from mixed C8 aromatic hydrocarbons.

The invention discloses a platinum-tungsten bimetallic catalyst for PET depolymerization and a method for directional depolymerization of PET by the platinum-tungsten bimetallic catalyst, and belongs to the technical field of solid waste recycling, the platinum-tungsten bimetallic catalyst for PET depolymerization is prepared by a deposition-precipitation method, a mesoporous molecular sieve MCM-48 is used as a carrier to load platinum-tungsten bimetallic, the molar ratio of platinum to tungsten is 1: (0.5-2), the molecular sieve MCM-48 is a mesoporous molecular sieve MCM-48, and the mesoporous molecular sieve MCM-48 is a mesoporous molecular sieve MCM-48 carrier. And the platinum loading capacity is 4-6 wt%. By utilizing the platinum-tungsten bimetallic catalyst, one-pot depolymerization of PET can be realized to prepare p-toluic acid and p-xylene, the platinum-tungsten bimetallic catalyst can be used for multiple times through reduction regeneration, the catalytic activity is high, and the PET depolymerization method under catalysis of the platinum-tungsten bimetallic catalyst is suitable for recycling and upgrading of PET wastes in various forms and has wide application prospects. The technical problems of efficient depolymerization and directional conversion of the waste PET are solved, and a sustainable technical path is provided for resource recycling of the PET.

The invention discloses a molecular sieve-based microsphere fluidized bed catalyst as well as a preparation method and application thereof. The catalyst comprises a transition metal modified molecular sieve, the molecular sieve is selected from at least one of ZSM-5, ZSM-11, ZSM-12, Silicate-I (at) ZSM-5, Silicate-I (at) Y, Silicate-I or Silicate-II type molecular sieves, the Si / Al molar ratio of the outer surface of the transition metal modified molecular sieve is larger than 250, and the Si / Al molar ratio of a body is 30-250; the transition metal is selected from at least one of Mn, Cu, Co or Ni. The catalyst disclosed by the invention is used in a reaction for preparing p-xylene through shape-selective methylation of aromatic hydrocarbon, so that the abrasion of the catalyst is remarkably reduced, and the conversion rate of toluene and the selectivity of p-xylene are improved.

The invention discloses a two-phase absorbent for capturing CO2, which is characterized by being prepared from the following components in percentage by mass: 25%-30% of N-(2-ethoxyl) ethylenediamine, 0%-3% of N-aminoethyl piperazine, 0%-3% of 2-(1-ethoxyl) pyridine, 10%-13% of N, N '-diethyl ethylenediamine, 15%-20% of N, N'-diethylethylenediamine, 5%-10% of N, N '-diethylethylenediamine, 5%-10% of N, N'-diethylethylenediamine and the balance of water. The invention relates to a cleaning agent which is prepared from the following components in percentage by weight: 1 to 5 percent of N, N-diethylhydroxylamine, 1 to 5 percent of pentamethyldiethylenetriamine, 0 to 2 percent of tert-butylamine ethoxyethanol, 0 to 3 percent of 2-amino-2-methyl-propyl alcohol, 5 to 8 percent of sulfolane, 5 to 8 percent of dimethyl ether, 5 to 8 percent of p-xylene and 5 to 8 percent of n-butyl alcohol. The composition can be prepared by uniformly stirring the components. The preparation method is simple, and the prepared two-phase absorbent can improve the saturated absorption capacity, improve the desorption rate and optimize the performance of the phase change absorbent.

The invention belongs to the technical field of chromatographic separation materials, and discloses a preparation method and application of a GM-8 nanosheet material. The preparation method of the material comprises the following steps: respectively dissolving Cu (NO3) 2.3 H2O and 1, 3, 6, 8-tetra (4-carboxybenzene) pyrene in an organic solvent, mixing, transferring into a reaction bottle, adding trifluoroacetic acid and pyridine, and uniformly mixing and stirring to obtain a reaction mixture; and heating the reaction mixture to react for 7-9 hours to obtain a blue precipitate, cooling the blue precipitate to room temperature, and washing and drying the blue precipitate to obtain the ultra-stable microporous GM-8 nanosheet material. The nanosheet GM-8 is used as a gas chromatography stationary phase, high-efficiency separation and trace detection of xylene isomers can be realized, and the chromatographic column still keeps excellent separation capacity after being stored in an environment with air humidity of 65-90% for 31 months. The capillary gas chromatographic column can realize high-efficiency separation of disubstituted benzene isomers such as xylene, the separation degree of m-xylene / p-xylene is up to 18.2, and a new solution is provided for high-efficiency separation of isomers with similar properties.

The invention relates to an adsorbent based on an X molecular sieve and preparation and application thereof, and a preparation method of the adsorbent comprises the following steps: (1) mixing the X molecular sieve with a binder, molding and roasting to obtain a molded body; (2) treating the molded body obtained in the step (1) with an alkali solution to perform in-situ crystallization on the binder in the molded body to obtain a crystallized product; (3) carrying out partial barium ion exchange on the crystallized product obtained in the step (2) by using a barium salt solution, and drying to obtain a dried product; (4) carrying out ammonium ion exchange on the dried product obtained in the step (3) by using an ammonium salt solution, and roasting in a flowing atmosphere to obtain a roasted product; and (5) performing barium ion exchange and optional potassium ion exchange on the roasted product obtained in the step (4), and then drying to obtain the adsorbent. The adsorbent has at least two kinds of mesoporous channels with different apertures, has high barium ion exchange capacity, high adsorption capacity and compressive strength, and shows good adsorption selectivity and mass transfer performance when used for adsorption separation of p-xylene.

The invention belongs to the technical field of petroleum and natural gas development, and particularly discloses a temperature response type water shutoff agent as well as a preparation method and a use method thereof. The temperature response type water plugging agent is composed of a main agent, an auxiliary agent and a conditioning agent, the mass ratio of the main agent to the auxiliary agent is (3-5): 1, the adding amount of the conditioning agent is 2%-8% of the mass of the main agent, and the main agent comprises, by mass, 20%-30% of triallyl isocyanurate, 20%-40% of chloropropene, 1%-5% of anhydrous sodium carbonate and the balance solvent; the auxiliary agent is prepared from the following components in percentage by mass: 40 to 70 percent of acetic acid-2-chloropropene ester, 20 to 30 percent of polyethylene glycol and 10 to 40 percent of p-xylene; the regulator is a hydrogen peroxide solution with the concentration of 30%. The temperature response type water plugging agent is in a liquid state at normal temperature, can be easily injected into an oil and gas reservoir, is stimulated by high temperature of the reservoir after entering the reservoir, generates phase change and is changed into a solid state from the liquid state, so that the water plugging effect is achieved; the plugging agent has a good plugging effect for a long time; the higher the temperature is, the easier the phase change is, and the better the use effect is.

The method is for producing para-xylene using, as a main raw material, a mixed gas of carbon dioxide or carbon monoxide or both thereof and hydrogen. The method including: a reaction step of bringing a raw material mixed gas including the mixed gas into contact with a reaction catalyst under high temperature and high pressure to cause a reaction, to thereby obtain a product gas mixture containing para-xylene; a separation step of cooling the product gas mixture obtained in the reaction step to condense a high boiling point component, to thereby separate the product gas mixture into a water phase containing a water-soluble component, an oil phase containing a xylene mixture, and a gas phase containing an unreacted gas; and a circulation step of mixing at least part of the gas phase having been separated in the separation step into the raw material mixed gas.

The invention discloses a lactobacillus brevis SMF L6 strain for improving the characteristic flavor of fermented fish and application thereof, and belongs to the technical field of aquatic product processing. According to the method disclosed by the invention, low-temperature fermentation is carried out by utilizing a sake lactobacillus wide cloth SMF L6 direct vat set fermentation inoculant to regulate and control the flavor; the method can effectively promote the production of flavor substances such as n-hexyl alcohol, eudesmol, 2-ethylhexyl alcohol, 4-platycladi alcohol, linalool, 4-terpene alcohol, alpha-terpilenol, piperonone, beta-myrcene, alpha-terpinene, D-limonene, beta-phellandrene, gamma-terpinene and the like in the fermented fish. The content of pungent smell and fishy smell substances such as acetic acid, p-xylene, o-xylene, trimethylamine, methyl mercaptan and carbon disulfide is reduced.

The invention belongs to the technical field of electronic components, and provides a xylene gas sensor based on a Co3O4 and In2O3 heterojunction, and a preparation process and application thereof. The xylene gas sensor comprises a gas sensitive material and an alumina ceramic tube, wherein the gas sensitive material is coated on the surface of the alumina ceramic tube. The gas sensitive material is a nano composite material formed by cobaltosic oxide and indium trioxide. The method is simple in production process, and the obtained gas-sensitive material shows relatively high sensitivity and rapid response and recovery to xylene. Due to the fact that a gas sensor with related achievements is too high in lower limit of detection of to-be-detected gas, the detection performance in a low-concentration environment is not ideal enough. According to the invention, the lower detection limit of the gas sensor can be greatly reduced, and the gas sensor still has obvious response under the concentration of 0.1 ppm, so that xylene in a gas environment can be timely found and protected.

The invention provides a p-xylene crystallization tower. The p-xylene crystallization tower comprises a tower body, a cooling structure and a scraper structure, mixed xylene is contained in the tower body; the cooling structure comprises a sealing plate and liquid conveying pipes arranged at the upper end and the lower end of the sealing plate respectively, and the sealing plate surrounds the periphery of the tower body; the sealing plate is wavy; the sealing plate comprises a plurality of wave trough parts and a plurality of wave crest parts which are alternately arranged, the wave trough parts are tightly connected with the periphery of the tower body, and the sealing plate and the periphery of the tower body define a circulation channel extending in the vertical direction between any two adjacent wave trough parts; the liquid conveying pipes are arranged on the periphery of the tower body in a surrounding mode, and the two liquid conveying pipes communicate with the multiple circulation channels correspondingly. And the refrigerating medium is input into the circulation channel through the liquid conveying pipe. And the mixed xylene is cooled under the action of the refrigerating medium, and paraxylene is crystallized and separated out on the inner circumferential wall of the tower body. And the scraper structure scrapes crystals on the tower body. According to the p-xylene crystallization tower, a refrigerating medium is in close contact with the tower body, so that the dissipation of cold energy is effectively reduced, and the refrigerating effect is improved.

The invention discloses a method for preparing an aromatic hydrocarbon product by catalyzing hydrogenolysis of oxygen-containing plastic through Ru-based amorphous molybdenum oxide. The method comprises the following steps: by taking oxygen-containing plastic as a raw material, mixing the raw material, a Ru-based catalyst and an n-hexane solvent in a reaction kettle, reacting for 2-6 hours under the conditions that the H2 pressure is 0.5-2 MPa and the reaction temperature is 220-300 DEG C, and depolymerizing the oxygen-containing plastic to obtain an aromatic hydrocarbon product, the Ru-based catalyst is composed of a carrier MoO3 and an active component ruthenium. According to the method, the conversion rate of the oxygen-containing plastic can reach 99%, the total yield of aromatic hydrocarbon products can reach 66.9-85.7 mol%, the yield of p-xylene can reach 60.2-77.2 mol%, and the selectivity of p-xylene is 84.6%-94.1%. The catalyst used in the invention has the advantages of low raw material cost and simple preparation process, and can depolymerize the oxygen-containing plastic under mild conditions to obtain high value-added chemicals such as aromatic hydrocarbon products.

Processes and facilities for producing a recycled content organic chemical compound directly or indirectly from waste plastic. Processing schemes are described herein for converting waste plastic (or hydrocarbon having recycled content derived from waste plastic) into useful intermediate chemicals and final products. The waste plastic can be liquified before being introduced to downstream processing. In some aspects, recycled content aromatics (r-aromatics) can be processed to provide recycled content paraxylene (r-paraxylene), which can then be used to provide recycled content terephthalic acid (r-TPA) and / or recycled content polyethylene terephthalate (r-PET).

The invention relates to an anti-allergic soothing cosmetic and a preparation method thereof. The invention discloses an N-Ala-Phe-Cys-C aqueous solution or an external cosmetic containing N-Ala-Phe-Cys-C for the first time, wherein the N-Ala-Phe-Cys-C aqueous solution or the external cosmetic has anti-allergic soothing effects. The eye cream has excellent single-time and multi-time skin external application safety, and is free of irritation to eyes. Compared with a blank control group, the cosmetics prepared from the 0.01-10% N-Ala-Phe-Cys-C aqueous solution and the formulas 1-4 of the embodiments 5-7 have a remarkable itching relieving effect, and have an inhibiting effect on allergic itching caused by histamine phosphate. Compared with a blank control group, the 0.05%-10% N-Ala-Phe-Cys-C aqueous solution and various formula cosmetics in embodiments 5-7 have a remarkable inhibition effect on auricle swelling caused by xylene.

The invention belongs to the field of integrated circuit plastic package, and particularly relates to a method for inhibiting internal layering of a plastic package circuit. The invention aims to solve the problem of internal layering of the plastic package circuit. According to the method for inhibiting layering in the plastic package circuit, a coupling agent, poly-p-xylylene and a coupling agent are respectively deposited in the circuit by adopting a vacuum gas phase deposition process, and nano fluorine is deposited on a plastic package outer layer. According to the invention, the waterproof and moistureproof capability of the device can be effectively enhanced, layering is inhibited, the plastic package material is not corroded after the device passes through HAST, high-pressure cooking and salt mist examination, and the appearance is kept clean and tidy.

The invention discloses a preparation method of a hydroxyl-functionalized quaternary phosphonium salt polyion liquid super-crosslinked heterogeneous catalyst and an application of the catalyst in catalysis of a cycloaddition reaction of CO2 and epoxide. Trimethoxytriphenylphosphine and dibromo-p-xylene are firstly subjected to quaternary phosphating to form triphenylphosphine-based ionic liquid, and then the triphenylphosphine-based ionic liquid and biphenyl benzyl dichloride can be subjected to aromatic electrophilic substitution reaction in the presence of 1, 2-dichloroethane serving as a solvent and anhydrous aluminum chloride serving as a Lewis acid catalyst to realize cross-linking, so that the triphenylphosphine-based ionic liquid can be prepared. And methoxy can be removed to form hydroxyl, so that the hydroxyl-functionalized quaternary phosphonium salt polyion liquid super-crosslinked polymer is prepared in one step. The resulting heterogeneous catalyst effectively converts CO2 to cyclic carbonates under milder conditions (80 DEG C, 1 atm) in the absence of a soluble co-catalyst.

The present invention relates to a method for surface modification of a MCM-22 molecular sieve shape-selective catalyst, belonging to the technical field of chemical engineering catalysis. In this preparation method, a macromolecular organic acid is selected to selectively remove the Al sites on the outer surface of the MCM-22 molecular sieve, and then a macromolecular silyl group is grafted onto the hydroxyl defect sites generated on the outer surface of the molecular sieve due to dealumination. This method can avoid blocking the pores of MCM-22, eliminate the outer surface acidity while retaining the internal activity of the molecular sieve, and reduce the pore mouth size, thereby obtaining a MCM-22 molecular sieve shape-selective catalyst with high activity, high selectivity and high stability. When this catalyst is applied to the reaction of alkylation of toluene with dimethyl carbonate to synthesize p-xylene, the activity of the catalyst remains 36% within 20 hours, and the selectivity can reach up to 66% at most.

The present invention provides a method for matching the film formation rate of C-type polyparaxylene dimer, comprising the following steps: S100, constructing a sublimation rate calculation formula, a cracking rate calculation formula, and a film formation rate calculation formula; S200, using the sublimation rate calculation formula, the cracking rate calculation formula, and the film formation rate calculation formula to respectively calculate the sublimation rate, the cracking rate, and the film formation rate, and by adjusting the corresponding sublimation temperature, the cracking temperature, and the film formation temperature, achieving equality of the sublimation rate, the cracking rate, and the film formation rate, thereby achieving speed matching in the film formation process of C-type polyparaxylene dimer. Utilizing the present invention, the film formation efficiency of C-type polyparaxylene dimer can be significantly improved, the product processing time can be shortened by more than 40%, the raw material utilization rate of C-type polyparaxylene dimer can be improved, and the film formation quality of C-type polyparaxylene dimer can be improved, and the C residual substances in the film formation process can be significantly reduced.

The application provides a catalyst and a preparation method and application thereof, and the catalyst comprises a carrier and an active metal component loaded thereon; the carrier comprises ZSM-5 zeolite and a binder, and the molar ratio of SiO2 / Al2O3 in the ZSM-5 zeolite is 15-50; the amount of strong acid centers on the outer surface of the catalyst is less than or equal to 10 mu mol / g; and the ratio of the saturated adsorption amount of p-xylene to the saturated adsorption amount of o-xylene of the catalyst is 3-20 under the condition of 400 DEG C. The catalyst provided by the application can catalyze the generation of benzene from toluene dealkylation under a medium-temperature condition, and the selectivity of benzene is good and the yield is high.

The application provides a C8 aromatic hydrocarbon isomerization catalyst and a preparation method and application thereof. The catalyst contains an active component and a carrier; wherein, based on the weight of the carrier, the carrier contains 5wt%-25wt% of HZSM-23, 5-30wt% of mordenite, 20-60wt% of macroporous alumina and 10wt%-25wt% of a binder component. The method comprises preparation of the carrier and loading of the active metal, wherein the preparation process of the carrier is as follows: HZSM-23 molecular sieve, mordenite, macroporous alumina and a binder are mixed and formed, and the carrier is prepared after drying and calcination. The catalyst is used for C8 aromatic hydrocarbon isomerization reaction, and has the characteristics of high ethylbenzene conversion rate and high xylene yield when the xylene is at an equilibrium concentration.

The application discloses a bifunctional catalyst for preparing p-xylene from carbon dioxide and hydrogen in one step, a preparation method and application, relates to the technical field of catalysts for preparing p-xylene from carbon dioxide and hydrogen, and opens up a new way for selectively hydrogenating carbon dioxide into high-value p-xylene; the application comprises alkali metal modified FeMn oxides and ZSM-5 capsule zeolites, and is used for converting CO2 into p-xylene through one-step hydrogenation; in the alkali metal modified FeMn oxides, Mn is dispersed on the oxide phase of Fe; the ZSM-5 capsule zeolites are subjected to hydrothermal treatment with a TPAOH solution, and the external passivated Bronsted acid sites of the ZSM-5 capsule zeolites can inhibit the structuralization reaction of dimethylbenzene; the bifunctional catalyst can realize the conversion of carbon dioxide into p-xylene in one step, has high carbon dioxide conversion rate, high space-time yield of p-xylene, and long catalyst service life.

A fluidized bed device for coupling naphtha and methanol to prepare aromatics and co-produce olefins and its application method are provided. By using the device, under the action of a catalyst, naphtha reacts with methanol to generate product gas containing aromatics and light olefins as main components. The method can efficiently and selectively convert linear and branched aliphatic hydrocarbons into aromatics, while also increasing p-xylene production through aromatic methylation reactions, with the p-xylene content in the xylene mixture exceeding 75 wt %. The fluidized bed reactor achieves increased p-xylene production by controlling the progression of cascade reactions (naphtha→benzene / toluene→p-xylene). Additionally, it utilizes the methylation reaction of benzene / toluene with methanol to provide in-situ heat for the coupled naphtha-methanol aromatization process, thereby achieving autothermal balance.

The invention discloses an application of p-xylene in prevention and control of straight-spot fly imagoes, and belongs to the technical field of agricultural planting research. Aiming at the problems that the yield of the chenopodium quinoa willd is seriously lost by the chenopodium quinoa willd and the existing prevention and treatment means only depend on chemical agents, the natural component p-xylene of the chenopodium quinoa willd is utilized to remarkably attract adults of the chenopodium quinoa willd, and the chenopodium quinoa willd attractant can be directly used for attracting the adults of the chenopodium quinoa willd and also can be used for preparing the attractant for the the concentration of p-xylene in the attractant is 0.1 mu g / mu L to 100 mu g / mu L. The application is green and environment-friendly, does not need to depend on chemical agents, provides a new way for green prevention and control of the adult straight-spot fly, broadens the prevention and control means of the chenopodium quinoa willd pests, and has important practical application value and scientific significance.

The invention relates to the technical field of waterproof plates, and provides a tear-resistant waterproof plate and a preparation method thereof. The tear-resistant waterproof board is prepared from the following raw materials in parts by weight: 30 to 35 parts of ethylene-vinyl acetate copolymer, 60 to 80 parts of tear-resistant master batch, 0.5 to 1.5 parts of first antioxidant and 3 to 4 parts of compatilizer, the tear-resistant master batch comprises the following raw material components in parts by weight: 20-30 parts of high-density polyethylene, 40-50 parts of linear low-density polyethylene, 1-3 parts of a processing aid and 0.5-1 part of a second antioxidant, and the processing aid comprises fluoro-dimer p-xylene and poly-alpha-methylstyrene. By means of the technical scheme, the problem that in the prior art, waterproof plates are insufficient in tear resistance is solved.

A method for producing 2,5-dimethylfuran according to one embodiment of the present invention includes a step for reacting a furan compound having a specific structure with hydrogen in a non-aqueous solvent in the presence of a hydrogenation catalyst. In this method for producing 2,5-dimethylfuran, the hydrogenation catalyst includes at least one type selected from among a first component group and at least one type selected from among a second component group. The first component group includes chromium, molybdenum, manganese, rhenium, ruthenium, rhodium, iridium, nickel, palladium, platinum, copper, zinc, and the like. The second component group includes aluminum oxide, silicon oxide, titanium oxide, zirconium oxide, carbon, and the like.

The utility model provides a cooling device which comprises a cooling cylinder, a plurality of first partition plates and second partition plates which are evenly distributed are arranged in the cooling cylinder, the first partition plates and the second partition plates are installed in a matched mode, a plurality of cooling pipes which are evenly distributed are arranged on the first partition plates and the second partition plates, and a plurality of stirring shafts which are evenly distributed are arranged in the cooling cylinder. And stirring paddles fixedly sleeve the middle parts of the outer arc surfaces of the stirring shafts. According to the cooling device disclosed by the utility model, when the dimethylbenzene stock solution is cooled, the dimethylbenzene stock solution can be continuously and quickly cooled by extending the flowing path of the dimethylbenzene stock solution in the cooling cylinder and matching with the stirring paddle.

Disclosed are apparatuses and processes for preparation and conversion comprising / using: a fractionation chain (4-6) that produces a xylene fraction (24); a xylene separation unit (10) that treats the xylene fraction to produce a para-xylene extract (39) and a raffinate (40); an isomerization unit (11) treating the raffinate to produce an isomerization product (42) of xylenes fed to the fractionation chain; the synthesis gas production unit (14; 15) that treats the hydrocarbon feedstock (30) to produce a synthesis gas (34) containing CO and CO2; a methanol synthesis reaction section (50) that treats the synthesis gas (34) to produce methanol (51); a toluene alkylation reaction section (13) treating the toluene-containing fraction (23) with methanol (51) to produce an alkylation effluent (32) containing xylene and fed to the fractionation chain.

This application provides an isolation structure and its manufacturing method. The isolation structure includes a substrate, an isolation trench, a flexible dielectric layer, and a filling layer located within the substrate. The flexible dielectric layer is made of hydroxyl-para-xylene. The filling layer covers the surface of the flexible dielectric layer and fills the isolation trench. This flexible dielectric layer can reduce cracks caused by excessive stress in subsequent thermal processes and can adapt to spatial distortion caused by the expansion of residual gas in the isolation trench through deformation under thermal conditions, reducing damage to the substrate, enhancing the electron coupling ability of the HiK material, improving the yield of devices on the substrate, and reducing dark current in devices and white spots in display images from the source. In addition, this flexible dielectric layer does not contain metal, so it will not cause metal ion contamination to the substrate. It eliminates the need for an additional isolation layer, improving the performance of devices on the substrate while simplifying device structure and processes and reducing manufacturing costs.