263 results about "Ethylbenzene" patented technology

Methods for upgrading heavy aromatic waste streams, such as polystyrene, to chemical feedstocks are disclosed. The process involves feeding waste streams to a first pyrolysis zone followed by hydrogenation. The hydrogenation effluent is processed to recover ethylene, propylene, benzene, ethylbenzene, or their precursors. Optionally, the effluents are separated into light and heavy streams. The light stream from the first pyrolysis effluent is sent to hydrogenation, while the heavy stream is either removed, recycled to the first pyrolysis zone, or fed to a second pyrolysis zone. The light stream from the hydrogenation effluent is processed to recover the same chemicals, and the heavy stream is similarly managed. If present, the second pyrolysis effluent is separated into light and heavy streams, with the light stream processed to recover chemicals and the heavy stream managed as before.

The invention relates to the technical field of all-solid-state batteries, in particular to air-stable argyrodite type sulfide electrolyte, a preparation method thereof and an all-solid-state battery. The air-stable argyrodite type sulfide electrolyte provided by the invention comprises a sulfide solid electrolyte and a protective layer formed by self-assembly of organic molecules on the surface of the sulfide solid electrolyte, wherein the sulfide solid electrolyte is argyrodite type sulfide solid electrolyte, the general formula of the sulfide solid electrolyte is Li < 7-a > PS < 6-a > X , X is halogen, and a is more than 0 and less than 2; the organic molecule is at least one of 1-methoxyhexane, 2-heptanone, 3-chloropropanol, 4-chlorobenzyl mercaptan, n-amylamine, 5-chloromethyl-1, 3-benzodioxole, chlorophenylmethane and ethylbenzene, and the organic molecule is at least one of 1-methoxyhexane, 2-heptanone, 3-chloropropanol, 4-chlorobenzyl mercaptan, n-amylamine, 5-chloromethyl-1, 3-benzodioxole, chlorophenylmethane and ethylbenzene. According to the air-stable argyrodite type sulfide electrolyte provided by the invention, the stability of the sulfide electrolyte to water can be enhanced, and the ionic conductivity of the sulfide electrolyte can be ensured.

The invention provides a method for preparing p-chloromethyl styrene, which comprises the following steps: (1) in the presence of a catalyst and an assistant, carrying out reaction on paraformaldehyde and hydrogen chloride to obtain a chloromethylation reagent; (2) reacting beta-halogenated ethyl benzene with the chloromethylation reagent obtained in the step (1) to obtain chloromethyl halogenated ethyl benzene; (3) adding an extracting agent into the chloromethyl halogenated ethylbenzene reaction liquid obtained in the step (2) for extraction to obtain an oil layer containing chloromethyl halogenated ethylbenzene and a water-containing acid layer, and crystallizing the oil layer to obtain purified p-chloromethyl halogenated ethylbenzene; and (4) in the presence of a solvent, carrying out elimination reaction on the purified p-chloromethyl halogenated ethyl benzene and alkali to obtain p-chloromethyl styrene.

The invention relates to a catalyst for preparing acetophenone by efficiently catalyzing selective oxidation of ethylbenzene in a hydrocarbon selective oxidation reaction, especially under a mild condition, a preparation method of the catalyst, and application of the catalyst provided by the invention. According to the catalyst for catalyzing selective oxidation of ethylbenzene to prepare acetophenone, monatomic Fe is anchored on a nitrogen-doped carbon carrier through a Fe-Nx coordination bond, the Fe content is 4-23 wt%, the BET specific surface area is 200-500 m / g, and Fe exists in Fe < + > and Fe < + > valence states. The catalyst can be used for preparing acetophenone through selective oxidation of hydrocarbons and has the advantages of being high in catalytic performance, stable in structure and good in substrate universality.

Disclosed is the use of a dividing-wall column in a process for co-producing propylene oxide and styrene monomer. Feed streams to a dividing-wall column comprise a bottoms product produced in recovering crude propylene oxide from an epoxidation reaction product, a hydrogenated byproduct styrene monomer production, and a light fraction of a bottoms product withdrawn from the dividing-wall column. Products from the dividing-wall column comprise an overhead product comprising ethylbenzene for recycle to an oxidation zone, an intermediate product comprising methylbenzyl alcohol and acetophenone as feed to a dehydration zone to produce styrene monomer, and a bottoms product comprising methylbenzyl alcohol and heavy materials.

This invention discloses a catalyst for the alkylation of tert-butanol with styrene to prepare tert-butylethylbenzene and ethylbenzene, its preparation method, and its application. The catalyst consists of a support and active components loaded on the support. The active components are oxides of rare earth metals and high-valence oxides of transition metals. The support is H-β zeolite. The mass contents of the oxides of rare earth metals and high-valence oxides of transition metals on the support are 3-5% and 2-4%, respectively. This invention makes a breakthrough in the reaction mechanism by loading rare earth metals and transition metals onto a β-molecular sieve and using tert-butanol and styrene as raw materials for alkylation. This avoids the polymerization of styrene (raw material) and the dimerization of isobutylene (intermediate product), reduces the generation of by-products, and makes the catalytic process controllable.

A method for preparing ethylbenzene by using nanosheet molecular sieve as catalyst, the hydrogen type nanosheet molecular sieve is broken and loaded into a fixed bed reactor, benzene and ethanol are used as raw materials, nitrogen is used as carrier gas, the reaction is carried out at 280-350 DEG C and 0.1-1.0 MPa; the hydrogen type nanosheet molecular sieve is ZSM-5 molecular sieve, the length of b axis direction is 70-100 nm, the length ratio L b / L a is less than 0.40. The method for preparing ethylbenzene provided by the application can be directly used for catalyzing ethanol and benzene to prepare ethylbenzene without secondary treatment such as modification of acid, alkali and alkali metal and rare earth metal elements based on the special structure of the nanosheet molecular sieve with ultra-short b axis, can ensure that the product is desorbed and diffused from the surface of the catalyst in time, reduces the probability of deep reaction of the product molecules, realizes high selectivity of the product ethylbenzene, and reduces the cracking and other side reactions.

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 invention relates to a method for producing styrene, starting from ethylbenzene, the method in particular involving the process of transferring heat from the obtained product gas flow to an H2O-containing flow. It has been found that the present method for producing styrene allows the heat required to carry out the dehydrogenation reaction to be efficiently recycled, in particular in order to heat the H2O-containing input flow being used.

The invention discloses a photochromic TiO2-PEG200 (Polyethylene Glycol 200) nano particle and an application of the photochromic TiO2-PEG200 nano particle in photocatalytic oxidation of a C-H bond. The catalyst is synthesized through a solvothermal method, PEG200 is used as a solvent and a modifier, and self-doped Ti < 3 + > and surface oxygen vacancies are introduced into TiO2. Under the irradiation of blue light (405nm), the catalyst generates a photochromic effect, Ti < 4 + > is reduced into high-concentration Ti < 3 + > in situ, and meanwhile, a large amount of superoxide free radicals (O < 2 + >) are generated. A photo-generated hole directly activates an ethylbenzene alpha-C-H bond to generate a benzyl free radical, and the benzyl free radical reacts with a superoxide free radical (O2.) and is finally converted into acetophenone. The catalyst has excellent visible light response and charge separation efficiency, and the acetophenone yield is up to 56 mmol.g <-1 >. H <-1 > and is 10 times that of traditional TiO2. The reversible circulation of Ti < 3 + > / Ti < 4 + > enables the catalyst to maintain good stability, and the activity is still maintained at 95% or above after five times of circulation. The operation conditions are mild (room temperature and normal pressure), a strong oxidant is not needed, an efficient, stable and environment-friendly photocatalysis solution is provided for C-H bond activation, and the method has important application value in the field of fine chemical synthesis.

According to the multi-construction layered metal oxide and the application thereof in hydro-conversion of the polystyrene waste plastic pyrolytic oil, the prepared multi-construction layered metal oxide serves as a catalyst and is fully mixed with the polystyrene waste plastic pyrolytic oil after being pretreated, and then the mixture is transferred into a reaction kettle; after sealing, filling hydrogen into the reaction kettle, controlling the reaction temperature to be 90-100 DEG C, and stirring to react for 6-12 hours; according to the invention, the multi-constructed NixAl-LDO is combined with the hydrogenation process, and the styrene conversion rate and ethylbenzene selectivity are improved by utilizing the combined action of the structural advantage of the multi-layer catalyst and the hydrogenation reaction.

The application discloses a lanthanum-cobalt composite catalyst and a preparation method and application thereof. The lanthanum-cobalt composite catalyst is composed of La2O2SO4, Co4S3 and Co3O4. Co(NO3)2.6H2O, La(NO3)3.6H2O, urea and sodium dodecyl sulfate are dissolved in an isopropyl alcohol solution to form a reaction solution, a precursor is obtained through a solvothermal method, and the lanthanum-cobalt composite catalyst is prepared through calcination. The prepared catalyst is used for selectively oxidizing ethylbenzene into acetophenone under the condition that molecular oxygen is used as an oxidant and no solvent is used, and excellent catalytic performance is shown. The catalytic system meets the requirements of green chemical industry and sustainable development.

A method and system for dehydrogenating ethylbenzene can include mixing a steam stream and an ethylbenzene stream to form a feed mixture. The ethylbenzene / steam feed mixture can then be fed into a dehydrogenation reactor containing an alkali metal promoted catalyst. A liquid selected from an alkali metal liquid, an alkali metal compound liquid, or a liquid solution containing an alkali metal can be injected into a feed stream (such as the steam stream, the ethylbenzene stream, or the ethylbenzene / steam feed mixture). After injection, the liquid vaporizes and disperses into the feed stream upstream of the dehydrogenation reactor. The liquid can remain liquid from a point upstream of the injection to the injection nozzle. The liquid is dispersed in liquid form through the injection nozzle to form liquid droplets dispersed in the feed stream, which evaporate and / or dissolve into the vapor feed stream.

The present application relates to the technical field of catalyst preparation, and is a catalyst for producing mesitylene from C9 mixed aromatic hydrocarbons and a preparation method thereof.The former is a non-noble metal supported molecular sieve catalyst, the catalyst carrier comprises a molecular sieve and a binder, the molecular sieve accounts for 70% to 90% of the weight percentage of the catalyst carrier, the loading of each element accounts for 1wt% to 10wt% of the weight percentage of the catalyst carrier, and the total loading of elements accounts for 5wt% to 15wt% of the weight percentage of the catalyst carrier.The catalyst for producing mesitylene from C9 mixed aromatic hydrocarbons has good catalytic performance, is applied to the process of producing mesitylene from C9 mixed aromatic hydrocarbons as a catalyst for alkylation reaction and isomerization reaction, finally eliminates the interference of methyl ethyl benzene, maximizes the production of mesitylene, the content of methyl ethyl benzene is less than 0.5%, and the yield of mesitylene is greater than 25%.

The invention provides polyether sulphone and a preparation method thereof. The preparation method comprises the following steps: mixing a polar aprotic solvent, a bisphenol monomer and an alkaline substance, introducing protective gas, heating, dehydrating, cooling to T1, adding a diphenyl sulfone monomer, and carrying out heat preservation at T1 to carry out a first-stage polymerization reaction; adding a low-polarity solvent, heating to T2, and carrying out second-stage polymerization reaction to obtain polyether sulfone; wherein the low-polarity solvent is selected from one or a combination of more than two of normal hexane, cyclohexane, methylbenzene, ethylbenzene, biphenyl and diphenyl ether. By reducing or partially inhibiting the generation of the cyclic oligomer in the reaction process, the polyarylether sulfone with narrow molecular weight distribution and low content of the cyclic polymer is obtained. The method provided by the invention is simple and easy to implement, is convenient to control, avoids complex product purification and separation processes, and is beneficial to industrial implementation.

The invention belongs to the technical field of high polymer material preparation, and particularly discloses narrow-distribution high-light-transmittance MS resin and a preparation method thereof. The preparation method specifically comprises the following steps: (1) conveying 25-65 parts by mass of methyl methacrylate (MMA), 25-65 parts by mass of styrene (ST) and 5-15 parts by mass of ethylbenzene (EB) into a mixing kettle, and uniformly mixing; (2) continuously conveying the mixed solution of methyl methacrylate, styrene and ethylbenzene into a plug flow reaction kettle according to a certain flow, initiating polymerization reaction through an initiator, and adding a chain transfer agent to adjust the polymerization molecular weight; and (3) carrying out two-stage devolatilization extrusion treatment to obtain the high-light-transmittance MS resin. The prepared MS resin has the following properties that the haze is smaller than or equal to 1.2%, and the light transmittance is larger than or equal to 92.5%.

The application provides a preparation method of a C8 aromatic hydrocarbon isomerization catalyst, which comprises the following steps: 1) mixing and forming EUO zeolite and a binder precursor into a carrier, and preparing a hydrogen type carrier after roasting and ammonium exchange; 2) performing composite modification treatment, which comprises hydrothermal treatment, acid treatment, and co-impregnation treatment using one or more compounds containing group IIIA-VIA elements or lanthanide series elements and a compound containing group VIII metal; 3) drying, roasting and reducing the solid to prepare the C8 aromatic hydrocarbon isomerization catalyst; and the application also provides the C8 aromatic hydrocarbon isomerization catalyst prepared by the above method, which comprises a carrier containing 5-35 mass% of EUO zeolite and 65-95 mass% of a binder, 0.02-0.15 mass% of one or more than two of group IIIA-VIA elements or lanthanide series elements, and 0.1-0.5 mass% of group VIII metal, which are calculated based on the carrier. When the catalyst prepared by the method is used in the C8 aromatic hydrocarbon isomerization reaction, the isomerization activity and the ethylbenzene conversion rate are obviously improved, and the aromatic hydrocarbon loss rate is low.

The invention relates to the technical field of ethylbenzene dehydrogenation, in particular to a preparation method and application of a spinel CoFe2O4 oxygen carrier, and the preparation method comprises the following steps: dissolving cobalt salt and iron salt in water according to a specific molar ratio, adding ethylene glycol, methanol and a polymethyl methacrylate template agent, uniformly mixing, drying, carrying out programmed temperature rise calcination in an oxygen-containing atmosphere, and calcining to obtain the spinel CoFe2O4 oxygen carrier. The CoFe2O4 oxygen carrier with a single spinel crystal structure is obtained. The oxygen carrier is used as a recyclable lattice oxygen source and can catalyze ethylbenzene oxidative dehydrogenation to generate styrene at the ultralow temperature of 200-400 DEG C, especially about 250 DEG C, both the ethylbenzene conversion rate and the styrene selectivity can reach 96% or above, and the performance degradation rate is smaller than 5% after at least 41 times of redox cycles. The process conditions are mild, the oxygen carrier structure is stable, the activity is high, and a new way is provided for energy-saving and low-carbon production of styrene.

The utility model relates to the technical field of reaction kettles, in particular to an anti-explosion polymerization device of a polystyrene reaction kettle, which structurally comprises a reaction kettle body, a feed port arranged at the top of the reaction kettle body, a stirring mechanism arranged above the reaction kettle body and used for stirring materials in the reaction kettle body, and a discharge pipe arranged at the bottom of the reaction kettle body. By arranging the feeding valve, the flow guide pipe, the three-way pipe, the first feeding pipe, the second feeding pipe, the first control valve and the second control valve, when stirring fails due to the fact that a stirring mechanism breaks down, ethylbenzene and nitrogen are injected into the reaction kettle body, and then the ethylbenzene and the nitrogen are fed into the reaction kettle body. Therefore, the concentration of styrene in the reaction kettle body is diluted, the reaction speed is stopped and slowed down, a stirring effect is achieved to a certain extent, a cooling effect on the reaction kettle is achieved, the temperature in the reaction kettle is prevented from increasing quickly, and the safety of equipment is improved.

The invention discloses zero-VOC (volatile organic compound) high-performance environment-friendly inorganic emulsion paint, the main components of the emulsion paint are inorganic components, and the used auxiliaries with organic groups are components without VOC release, so that the release amount of VOC (including organic substances such as dimethylbenzene, formaldehyde, ethylbenzene and the like harmful to a human body) at room temperature can be reduced to 0; the inorganic latex paint coating is burnt at 1500 DEG C, no VOC is released, harmful gas can be prevented from being released during construction at room temperature, harmful gas can be prevented from being released at high temperature in the using process, and the coating is environmentally friendly and safe; silica sol and allylbenzene in the emulsion can form films, and potassium silicate is reasonably matched with silica sol-allylbenzene and other components.

The invention discloses a solvent-participation-free synthesis process of p-ethyl propiophenone, which comprises the following steps: by taking ethylbenzene and propionyl chloride as raw materials and phosphorus trichloride and lewis acid as catalysts, carrying out Friedel-Crafts acylation reaction without adding other reaction solvents to obtain the p-ethyl propiophenone. Compared with the prior art, the method has the advantages that the generation of disubstituted impurity 1-(2, 4-diethyl phenyl) propan-1-ketone is unexpectedly and effectively avoided, the impurity generation amount is less than 5%, the yield and the purity of p-ethyl propiophenone are greatly improved, and the synthesis process is green, environment-friendly, low in cost and convenient for realizing industrial production, and can be used for industrial production of eperisone.

The invention discloses a method for separating and purifying hydrogen from ethylbenzene dehydrogenation tail gas by using an MOF (Metal Organic Framework) membrane separation device, which belongs to the technical field of advanced membrane separation, adopts a zeolite membrane, a polymeric membrane, a carbon membrane and an MOF membrane as membrane materials, can realize high purification of hydrogen in the tail gas, and comprises the following steps: pretreating the ethylbenzene dehydrogenation tail gas in a pretreatment unit; the pretreated raw materials are fed into MOF membrane separation equipment through a flow controller or a pump to be separated, a permeation component hydrogen is extracted from a permeation side by using a pump or N2 purging or differential pressure pushing, and a retentate side is connected with a back pressure valve to extract other impurity components of a retentate component. According to the method, efficient purification and recovery of hydrogen from ethylbenzene dehydrogenation tail gas are realized, the hydrogen production capacity can be remarkably increased, and the economic benefit is improved.

The present invention discloses a modified hollow ceramic fiber and its preparation method and application. The modified hollow ceramic fiber comprises a hollow ceramic fiber, and the inner surface of the hollow ceramic fiber includes a silane layer, a first modification layer and a second modification layer from outside to inside; the first modification layer contains a tertiary amino group or a phenoxy group; the second modification layer contains a secondary amino group, a primary amino group and a pyridyl group. The preparation method of the modified hollow ceramic fiber includes: subjecting the hollow ceramic fiber to a silanization treatment to obtain a silanized hollow ceramic fiber; then successively performing a first modification treatment, a second modification treatment and an activation treatment on the obtained silanized hollow ceramic fiber to obtain a modified hollow ceramic fiber. The modified hollow ceramic fiber of the present invention is suitable for efficiently removing sulfur-containing impurities that affect the activity of the ethylbenzene alkylation catalyst in dry gas.

The invention discloses a system and a method for preparing ethylbenzene from benzene and ethanol, the system comprises a mixer, a first preheater and a first heater which are connected in sequence, and the mixer is respectively connected with a benzene feeding pipeline and an ethanol feeding pipeline; the multi-section adiabatic fixed bed reactor comprises a plurality of sections of adiabatic fixed bed reactors which are connected in sequence, an inlet of the first section of adiabatic fixed bed reactor is connected with the first heater, and an outlet of the last section of adiabatic fixed bed reactor is connected with a first separation tower through a condenser; the system further comprises a raw material supplementing pipeline; the tower top and the tower bottom of the first separation tower are respectively connected with a second separation tower and a third separation tower; and the tower bottom and the tower top of the third separation tower are respectively connected with a fourth separation tower and a fifth separation tower. The temperature difference between the inlet and the outlet of the reactor is small, the content of byproducts is reduced, the recovery purity of benzene is high, the moisture content is low, and the influence of moisture on the catalyst is reduced.

The present invention relates to catalysis field and is specifically related to a kind of preparation method of p-Xylene, the method including:Using 2,5-dimethylfurans and / or 2,5-hexanedione as raw material, the catalyst contains SCM-36 molecular sieves, and raw material and ethylene contact reaction prepare p-Xylene in the presence of alternatively organic solvent.Using SCM-36 molecular sieves as catalyst, under mild reaction conditions, 2,5-dimethylfurans and / or 2,5-hexanedione can be efficiently converted into p-Xylene, and conversion rate and product p-Xylene selectivity are very high.Meanwhile, in products obtained therefrom, key impurities (such as polyalkyl ethylbenzene, 2,5-hexanedione and 2-cyclopentenone) content is extremely low, greatly reducing separation energy consumption.In addition, the present invention has very high stability by using SCM-36 molecular sieves as catalyst, and is recycled four times without seeing catalyst performance significantly changed.

This invention discloses a method and device for monitoring anomalies in ethylbenzene production based on a semantically guided diffusion model. The method includes: acquiring multivariate raw time-series data of the ethylbenzene production process and extracting corresponding process logic text to construct multidimensional semantic feature guidance vectors; inputting the raw time-series data into a pre-trained diffusion model for reconstruction, obtaining reconstructed time-series data; employing an improved residual block structure in the diffusion model's denoising network, embedding semantic guidance branches in the residual paths, and injecting the semantic feature guidance vectors into the time-series feature space using a cross-attention mechanism; calculating the reconstruction residual between the raw time-series data and the reconstructed time-series data, and adjusting the constraint strength of the semantic features based on a classifier-free guidance strategy to amplify anomaly bias; calculating anomaly scores based on the reconstruction residuals to determine whether an anomaly has occurred in the ethylbenzene production process. This invention improves the detection accuracy of hidden anomalies under complex chemical operating conditions through deep coupling of process semantic features and the diffusion model.

The present invention relates to the technical field of separation of direct coal liquefaction oil, and provides a method for separating and purifying monocyclic aromatic hydrocarbons from direct coal liquefaction oil. The method comprises: (1) performing fractional distillation and composition analysis on direct coal liquefaction oil to determine a fraction having the highest content of monocyclic aromatic hydrocarbons; (2) removing low-carbon alkanes and cycloalkanes from a selected fraction by means of column chromatography; (3) separating toluene, a monocyclic aromatic hydrocarbon mixture, and high-carbon alkanes by means of an atmospheric and vacuum distillation column; (4) purifying ethylbenzene from the monocyclic aromatic hydrocarbon mixture by means of an extractive distillation column; and (5) purifying p-xylene by means of a solvent recovery column. The separation method provided by the present invention can make full use of the composition characteristics of direct coal liquefaction oil to obtain two or three high-purity monocyclic aromatic hydrocarbon monomers at a time without introducing additional chemical reaction steps, showing significant economic and environmental benefits.

The present invention relates to the technical field of ethylbenzene separation, and discloses a method for separating ethylbenzene from C8 aromatic hydrocarbon, the method comprises: (1) rectifying a C8 aromatic hydrocarbon raw material to obtain a first material flow rich in ethylbenzene; in the first material flow, the content of ethylbenzene is not lower than 70wt%; (2) in the presence of a xylene adsorbent and a desorption agent, carrying out adsorption separation on the first material flow to obtain an extract rich in xylene and a raffinate rich in ethylbenzene; and (3) removing the desorption agent in the raffinate rich in ethylbenzene to obtain a second material flow rich in ethylbenzene. According to the method provided by the invention, the ethylbenzene separation efficiency can be remarkably improved, the use amount of the adsorbent can be greatly reduced, the ethylbenzene purity is high, and the system energy consumption is low.

Disclosed are methods for upgrading heavy aromatic waste streams, including polystyrene and other related materials, to chemical feedstocks. Process embodiments include feeding heavy aromatic waste streams to: a) thermal pyrolysis followed by catalytic pyrolysis; b) thermal pyrolysis followed separation of thermal pyrolysis effluent to light and heavy streams followed by catalytic pyrolysis of the light stream; c) thermal pyrolysis followed by catalytic pyrolysis of the thermal pyrolysis effluent followed separation of the catalytic pyrolysis effluent to light and heavy streams; and d) thermal pyrolysis followed separation of thermal pyrolysis effluent to light and heavy streams followed by catalytic pyrolysis of the light stream followed by separation of the catalytic pyrolysis effluent to light and heavy streams. Each embodiment leads to production of ethylene, propylene, benzene, ethylbenzene, ethylbenzene precursors, or a combination thereof.

The invention relates to the technical field of chemical catalysis, in particular to a method and system for preparing p-methyl-ethylbenzene through alkylation. According to the method, reactants and a catalyst react under the conditions that the temperature is 300-500 DEG C and the pressure is 0.1-2.0 MPa, and p-methyl-ethylbenzene is obtained, the reactants comprise an aromatic hydrocarbon raw material and an alkylation reagent; the catalyst is spherical particles, reactants are in countercurrent contact with the catalyst, and the mass space velocity of the aromatic hydrocarbon raw material is 1.0-20 h <-1 >. The method can efficiently convert an aromatic hydrocarbon raw material and an alkylating reagent under mild conditions, directly obtains p-methyl-ethylbenzene in one step, and is high in reaction efficiency and low in energy consumption; the selectivity of p-methyl-ethylbenzene is high, the product purity is high, the yield is high, and the catalyst is renewable; the system is simple in structure and suitable for large-scale production.