25 results about "Methyl nitrite" patented technology

The invention discloses a method for preparing dimethyl carbonate through reaction of CO and methyl nitrite, belongs to the technical field of preparation of dimethyl carbonate, and aims to solve the problem that in the prior art, in the process of preparing dimethyl carbonate through catalysis of reaction of CO and methyl nitrite, the reaction time is short. The preparation method specifically comprises the following steps: in an inert gas atmosphere, mixing and stirring isocyanatopropyltriethoxysilane and N, N-dimethylformamide, raising the temperature of a reaction system to 50-60 DEG C, carrying out a reaction for 1-2 hours, and carrying out a reaction for 1-2 hours, so as to obtain a reaction solution; and 3-aminopropionic acid is added into the reaction system. According to the method, silicon-aluminum coating, potassium modification and 18-crown-6-ether modification are sequentially performed after a halogen-free palladium-copper catalytic system is prepared, so that the conversion rate of impurities and the chromatic value of a product are reduced, the conversion rate of methyl nitrite is effectively increased, and the service life of the catalyst is effectively prolonged.

The invention discloses a method for preparing methyl nitrite through nitric acid reduction, belongs to the technical field of methyl nitrite preparation, and aims to solve the technical problem that the nitric acid conversion rate and the reaction selectivity of the methyl nitrite prepared through nitric acid reduction in the prior art need to be further improved. The preparation method specifically comprises the following steps: roasting and activating a mixed catalyst, and uniformly stirring to obtain an activated catalyst. Through preparation of the active catalyst, construction of a composite network, optimization of a pore structure and metal dispersion through hydrothermal treatment and calcination in the preparation process, and rapid generation of NO < + > at a copper site in the reaction process, the preparation process is simple, and the preparation process is convenient. The catalyst diffuses to tin sites and performs nucleophilic substitution with methanol to generate methyl nitrite, proton feedback drives NO < + > to be continuously generated, efficient mass transfer is ensured by utilizing regular pore channels, the conversion rate of nitric acid and the selectivity of methyl nitrite are remarkably improved through the synergistic effect of Cu-Sn, side reactions are reduced, and the catalyst is suitable for industrial production.

The invention belongs to the technical field of catalyst preparation, and particularly relates to a preparation method of a novel NaY molecular sieve supported palladium and metal additive catalyst for co-production of dimethyl carbonate, the catalyst mainly comprises 0.1-3.0% by mass of Pd active component, 0.1-10.0% by mass of metal additive and 0.1-10.0% by mass of NaY molecular sieve carrier. The metal auxiliary agent not only effectively eliminates acid in the catalyst, but also promotes the generation of high-valence Pd active species, and the Pd active species are stabilized by utilizing the electron withdrawing effect of the auxiliary agent on the Pd active species. The catalyst is applied to a reaction for synthesizing dimethyl carbonate by carbonylation of methyl nitrite in a process of co-producing ethylene glycol from coal and co-producing dimethyl carbonate, shows excellent catalytic performance, and has certain industrial application prospects.

The utility model relates to the field of a dimethyl oxalate synthesis process, in particular to a nitric acid feeding line and dimethyl oxalate production equipment, an original nitric acid liquid inlet subline is cancelled, and a nitric acid boundary valve is arranged at the output end of a nitric acid feeding system to control the flow of nitric acid entering a specific area or system, so that the nitric acid is ensured to flow in a specified range; it is ensured that nitric acid can stably and continuously enter the next link through a nitric acid feeding valve; through the arrangement of the nitric acid drainage regulating valve and the check valve behind the nitric acid feeding valve, after nitric acid supplementing is stopped, the nitric acid in the pipeline is released through the nitric acid drainage regulating valve, nitric acid accumulated liquid stored in the pipeline is avoided, and therefore the situation that the nitric acid flows backwards and reacts with liquid stored in the pipeline is doubly avoided; and the safety of the pipeline is further improved. The problem that the accident risk is high due to the fact that nitric acid feed of an existing nitric acid reduction tower accumulates in a pipeline and reacts with alcohol-containing liquid of a methyl nitrite regeneration tower reversely into the nitric acid pipeline is solved.

The invention relates to a synthesis method of dimethyl oxalate, and mainly solves the technical problems of high reaction hot spot temperature, poor dimethyl oxalate selectivity and low space time yield in the prior art. According to the technical scheme, carbon monoxide, nitrogen and methyl nitrite (MN) are used as raw materials, and under the conditions that the inlet temperature is 70-100 DEG C, the volume space velocity is 1000-5000h <-1 >, the CO molar concentration is 10-40%, the CO / MN molar ratio is 1.0-3.0 and the reaction pressure is 0.05-2.0 Mpa, the raw materials pass through a Pd catalyst diluted by small balls with low specific surface area, large aperture and low acid content, the hot-spot temperature of a bed is lower than 125 DEG C, and the reaction is carried out for 1-2 hours, so that the methyl nitrite (MN) is obtained. According to the technical scheme, the problems are well solved, the selectivity of the dimethyl oxalate is larger than 98% in the long-time operation process, the space time yield of the dimethyl oxalate is larger than 750 g / (L.h), and the method can be used for industrial production of synthesizing the dimethyl oxalate through oxidative coupling of carbon monoxide.

The invention discloses a catalytic synthesis method of methyl nitrite, belongs to the technical field of methyl nitrite synthesis, and is used for solving the technical problem that the selectivity of catalytic synthesis of methyl nitrite in the prior art needs to be further improved. The catalytic synthesis method specifically comprises the following steps: adding lanthanum nitrate, copper nitrate, palladium chloride and deionized water into a beaker; the preparation method comprises the following steps: adding amino graphene and aluminum silica gel into a reaction kettle, stirring at room temperature for 10-20 minutes, adding ethylene glycol, continuously stirring for 15-30 minutes, adding a composite carrier into a system, adjusting the pH value to 3-4 by using saturated dilute nitric acid, heating to 50 DEG C, reacting for 12-15 hours, and performing post-treatment to obtain the modified catalyst. The reaction conversion rate, selectivity and catalyst stability are improved.

The application discloses a chlorine-free type palladium-based catalyst for gas-phase carbonyl synthesis of dimethyl carbonate and a preparation method and application thereof. The catalyst comprises an active component Pd and a molecular sieve carrier; wherein the molecular sieve carrier is further loaded with structural stabilizing aids Cu, K and metal M; in the catalyst, the Pd is 0.25-2% in mass percentage, the Cu is 0.05-10% in mass percentage, the K is 0.01-5% in mass percentage, and the M is 0.01-1% in mass percentage. The catalyst is prepared by firstly loading the Cu, K and metal M on the molecular sieve carrier to obtain a skeleton-modified Cu-K-M-molecular sieve carrier, configuring the carrier into a suspension, then adding a palladium precursor solution drop by drop into the suspension for ion exchange, and finally calcining in an oxidizing atmosphere. The catalyst has high activity and high stability, and the preparation method is simple, green and environment-friendly. When applied to a CO and methyl nitrite gas-phase carbonyl synthesis process of dimethyl carbonate, the catalyst can eliminate the problems of deactivation of a chlorine-containing catalyst and corrosion of equipment, and has industrial application potential.

The present invention provides a method for synthesizing dimethyl fumarate and dimethyl maleate by dicarbonylation of acetylene, which uses acetylene, carbon monoxide and methyl nitrite as raw materials, and reacts them under the action of a supported palladium catalyst at a temperature of 60-200°C. o C. Under conditions of pressure of 0.1 to 6 MPa, acetylene is subjected to a double carbonylation reaction for 0.5 to 48 hours to obtain dimethyl fumarate and dimethyl maleate compounds. The present invention replaces methanol with methyl nitrite and employs a supported palladium catalyst, eliminating the need for any auxiliary agents and the direct use of O2. This avoids the problems of explosion limits, the use of corrosive auxiliary agents, and the separation and recycling of catalysts in the current double carbonylation of acetylene, overcoming the technical pain points of the prior art. Furthermore, the reaction has the advantages of high atomic utilization, mild reaction conditions, and high product yields. The byproduct, NO, can be recycled, making it suitable for industrial production and promising broad application prospects.

The invention discloses a mass correction factor-based soluble methyl nitrite content determination method and a mass correction factor-based soluble methyl nitrite content determination system, and belongs to the technical field of methyl nitrite content determination. According to the method, an alcohol substance is adopted as a reference substance, a reliable bridge is provided for indirect quantification, and the problems that a conventional reference substance is poor in compatibility and prone to volatilization or hydrolysis are solved; secondly, an indirect quantitative system of the gaseous correction factor and the liquid reference content is established, the content of the methyl nitrite can be accurately measured without a dissolved methyl nitrite standard sample for the first time, and the technical problem that direct quantification is difficult due to lack of a special liquid standard substance in the prior art is solved.

The invention discloses a method for increasing the load of a dimethyl oxalate synthesis system and reducing the content of methyl nitrite in the system, and the method comprises the step of arranging a tubular reactor connected with a reactor A / B in parallel on a pipeline between a preheater and a gas removal tower. After the rotating speed of a compressor is adjusted, the circulating flow of outlet gas is controlled to be 420000-440000 Nm < 3 > / h, and meanwhile effective gas components entering the tubular reactor and the reactor A / B in the system are controlled to comprise 16%-22% of CO, 3%-6% of NO and 12%-14% of MN; s2, after feeding of the reactor A / B and the tubular reactor is completed, a flow adjusting valve at an inlet of the tubular reactor is immediately adjusted, the ratio of the flow of the inlet of the reactor A / B to the flow of the inlet of the tubular reactor is controlled to be 4.5-5.5: 1, and meanwhile the content of methyl nitrite in the system is controlled to be 14.5%-15.8%. The bottleneck problem of high safety production risk caused by low dimethyl oxalate synthesis yield and high methyl nitrite content in the original system is solved.

Provided is a supported catalyst for preparing carbonates, such as dimethyl carbonate from methyl nitrite and carbon monoxide, including: (a) an active metal component of IUPAC groups 8 to 10; (b) a metal additive selected from at least one of groups 11, 12, 5, 6 and 7; and (c) a modified carrier treated with a non-metallic modifier selected from at least one of groups 15 to 17, wherein, the catalyst has one or more "acidic sites" between 0-500°C as analysed by the NH3-TPD method. The active metal component can be, e.g., rhodium or palladium; the metal additive can be, e.g., copper or zinc; the non-metallic modifier of the modified carrier can be, e.g. ammonia for alumina as carrier or orthophosphoric acid for a silica carrier.

The application discloses a method for preparing dimethyl carbonate by reacting CO and methyl nitrite, belongs to the technical field of dimethyl carbonate preparation, and aims at solving the technical problems of high impurity conversion rate, high colority, and further improved conversion rate of methyl nitrite and service life of a catalyst in the process of preparing dimethyl carbonate by catalyzing the reaction of CO and methyl nitrite in the prior art, and specifically comprises the following steps: stirring isocyanic acid propyl triethoxysilane and N,N-dimethylformamide under an inert gas atmosphere, increasing the temperature of a reaction system to 50-60 DEG C, and adding 3-aminopropionic acid into the reaction system. The application is prepared by preparing a halogen-free palladium copper catalytic system, and then sequentially performing silicon aluminum coating, potassium modification and 18-crown-6-ether modification, so that the conversion rate of methyl nitrite and the service life of the catalyst are effectively improved while the impurity conversion rate and the colority value of the product are reduced.

The invention discloses a method and a device for efficiently producing methyl nitrite. The method comprises the following steps: carrying out a reaction for generating methyl nitrite in a reaction chamber A to obtain a liquid-phase material, and transferring nitric acid out of the liquid-phase material in the reaction chamber A through an acid transfer concentration device; wherein the liquid-phase material after the nitric acid is transferred serves as a reaction raw material and is reused in the reaction chamber A; transferring the transferred nitric acid into a reaction chamber B; when the mass concentration of the nitric acid in the reaction chamber B is larger than or equal to a first set value, the reaction of converting the nitric acid into methyl nitrite is carried out in the reaction chamber B; when the mass concentration of the nitric acid in the reaction chamber B is less than or equal to a second set value, stopping the reaction for generating the methyl nitrite; the first set value is greater than the second set value. According to the device and the method, oxidative esterification and nitric acid conversion reaction can be simultaneously carried out, methyl nitrite is efficiently produced, the total space-time yield of the product is improved, and the process energy consumption and cost are reduced.

The invention discloses a method for purifying dimethyl carbonate, belongs to the technical field of dimethyl carbonate processing, and is used for solving the technical problem that in the prior art, the process for synthesizing and preparing electronic-grade dimethyl carbonate from carbon monoxide and methyl nitrite is complicated. A dimethyl carbonate purification method is used for purification of a degassing tower kettle material for preparing dimethyl carbonate from CO and methyl nitrite, and comprises the following steps: mixing the degassing tower kettle material and activated carbon, and raising the temperature of a reaction system to 70-80 DEG C; according to the present invention, the dimethyl carbonate rectification process is optimized, and the prepared adsorption filler is adopted to perform adsorption impurity removal on the rectified dimethyl carbonate, such that the purity of the dimethyl carbonate is effectively improved, the content of methanol, water, metal ions and other impurities in the dimethyl carbonate is effectively reduced, and the prepared electronic-grade dimethyl carbonate product has the advantages of environmental protection and environmental protection. And the post-treatment process is simplified, and the production requirements are better met.

This invention discloses a purification method for dimethyl carbonate, belonging to the field of dimethyl carbonate processing technology. It addresses the complex technical problem of synthesizing electronic-grade dimethyl carbonate from carbon monoxide and methyl nitrite in existing technologies. The method purifies the bottom material of a degassing tower used in the preparation of dimethyl carbonate from CO and methyl nitrite, comprising the following steps: mixing the bottom material from the degassing tower with activated carbon, and raising the reaction system temperature to 70-80°C. This invention optimizes the distillation process of dimethyl carbonate and uses a prepared adsorption packing to adsorb and remove impurities from the distilled dimethyl carbonate. This not only effectively improves the purity of dimethyl carbonate and reduces the content of impurities such as methanol, water, and metal ions, but also simplifies the post-processing of the resulting electronic-grade dimethyl carbonate product, better meeting production requirements.

The invention relates to the technical field of preparation of chemical catalysts, in particular to a catalyst for co-production of dimethyl oxalate and dimethyl carbonate from carbon monoxide and methyl nitrite and a preparation method of the catalyst. The catalyst comprises a carrier, an active component and an auxiliary agent, wherein the carrier is nano ore crystal, the active component is precious metal palladium, the mass fraction of the active component in the carrier is 0.02%-0.05%, the auxiliary agent is alkali metal, and the mass fraction of the auxiliary agent in the carrier is 0.1%-2.0%; pd in the catalyst can be combined with the alkali metal additive and is uniformly distributed on the surface of the carrier. The co-production catalyst is suitable for the reaction of synthesizing dimethyl oxalate and dimethyl carbonate from gas-phase carbon monoxide and methyl nitrite, and has the advantages of high target product selectivity, high raw material conversion rate, low cost, long service life and the like.

The invention discloses a Pd / M-CeO2 single-site catalyst, a preparation method thereof and application of the Pd / M-CeO2 single-site catalyst in preparation of dimethyl carbonate through CO esterification, and belongs to the field of catalysts. The catalyst comprises an active component Pd and a CeO2 carrier doped with metal M, m is selected from at least one of rare earth lanthanide elements and IIIA main group elements. When the catalyst is applied to preparation of dimethyl carbonate through CO esterification, decomposition of methyl nitrite can be reduced, and the catalyst has high dimethyl carbonate selectivity which can reach 92%.

The invention belongs to the technical field of catalyst preparation, and particularly relates to a preparation method of a novel catalyst for co-producing dimethyl carbonate and anchoring palladium metal through molecular sieve defects. The molecular sieve supported noble metal Pd catalyst is prepared, the type of the molecular sieve is one or a combination of more of FAU, MOR, FER, LTL, MFI, beta, ZSM-5 and silicalite-1, and the noble metal Pd accounts for 0.1%-2.5% of the mass of the catalyst. The catalyst is applied to a reaction for synthesizing dimethyl carbonate by carbonylation of methyl nitrite in a process of co-producing ethylene glycol from coal and co-producing dimethyl carbonate, solves the problem that a traditional chlorine-free catalyst is easy to inactivate, is a high-stability, high-selectivity, high-conversion-rate, anti-sintering and chlorine-free high-performance catalyst, and has a certain industrial application prospect.

The invention belongs to the technical field of synthesis of CI chemical and fine chemical intermediates, and particularly relates to a catalyst and a method for preparing dimethyl oxalate and dimethyl carbonate by taking CO-containing industrial tail gas and methyl nitrite as raw materials. The catalyst provided by the invention comprises a carrier, an active component and an auxiliary agent, wherein the carrier is a molecular sieve, the active component is noble metal palladium, the mass fraction of the noble metal palladium in the carrier is 0.1-0.5%, and the auxiliary agent is one or more of Cu, Zn and La, and the mass fraction of the auxiliary agent in the carrier is 0.1-2.0%. According to the catalyst, industrial tail gas such as steel mill tail gas and coal chemical tail gas can be directly utilized to react with methyl nitrite, the CO conversion rate is 80%-95%, the DMO selectivity is 40%-90%, the DMC selectivity is 10%-60%, and the total selectivity is larger than or equal to 99.5%.

This invention discloses a method for determining the concentration of soluble methyl nitrite based on a mass correction factor, belonging to the field of analytical chemistry. Using an organic compound that can be prepared as both a gaseous and liquid standard as a reference substance, the concentration of soluble methyl nitrite in the alcohol-containing liquid sample is obtained by measuring the relative mass correction factor of gaseous methyl nitrite with respect to the gaseous reference substance and combining this with the measured concentration of the liquid reference substance in the sample. This method can accurately determine the concentration of soluble methyl nitrite without requiring a standard sample, is simple to operate, has good repeatability, and provides accurate and stable results. It solves the problems of poor compatibility between conventional reference substances and alcohol-containing liquid sample matrices, as well as their volatility or hydrolysis, which lead to inaccurate quantification. This method enables the direct and accurate determination of the concentration of soluble methyl nitrite and can be used for the precise analysis of soluble methyl nitrite in alcohol-containing liquid systems in chemical production.

The invention discloses a preparation method of a carbonylation catalyst for synthesizing dimethyl oxalate, and the preparation method comprises the following steps: (1) dissolving aluminum oxide, manganese oxide and an SAPO-5 molecular sieve in an organic solvent, stirring, and drying to obtain a composite carrier; (2) taking palladium salt and zinc salt as active components, taking calcium salt and cerium salt as auxiliary components, and respectively dissolving the active components and the auxiliary components in deionized water to prepare an active salt solution and an auxiliary salt solution; (3) dipping the composite carrier in an additive salt solution, taking out, drying, and roasting to obtain a solid; and (4) dipping the solid in an active salt solution, taking out, drying, and roasting to obtain the carbonylation catalyst. The carbonylation catalyst prepared by the method has high activity and selectivity in the reaction of catalyzing carbon monoxide and methyl nitrite to prepare dimethyl oxalate, and the preparation method is simple and easy for industrial application.

The application provides an eggshell type catalyst and a preparation method and application thereof. The eggshell type catalyst comprises an active component, an auxiliary active component and a carrier, the active component comprises PdCl2, the PdCl2 is loaded on the surface layer of the carrier, and the auxiliary active component comprises CuCl2, the CuCl2 is loaded on the surface and the inside of the carrier. Based on the structural characteristics of the eggshell type catalyst, the utilization efficiency of the noble metal Pd is high, the economic benefit is good, the auxiliary active component CuCl2 has good valence stability on the Pd, and the eggshell type catalyst has good selectivity and space-time yield in the reaction of low-pressure gas-phase synthesis of dimethyl carbonate from CO and methyl nitrite.

The present invention relates to the technical field of novel chemical processes, and disclosed herein are a production process and system for co-production of dimethyl oxalate and dimethyl carbonate. The co-production process ingeniously utilizes the characteristic that the top of a nitric oxide / methanol / nitric acid redox column in a dimethyl oxalate synthesis process is enriched in methyl nitrite, and the requirement of a raw material ratio of a chlorine-free dimethyl carbonate synthesis catalyst can be well met for production of dimethyl carbonate only by simple purification and adjustments. The co-production process involves a simple process and less capital investment, the product structure can be adjusted in a timely manner, and economic benefits can be increased.

The utility model belongs to the technical field of equipment for preparing ethylene glycol from synthesis gas, and particularly relates to dimethyl oxalate, methanol and methyl nitrite volatile gas treatment equipment which comprises a treatment tank, two partition plates are arranged in the treatment tank, and the internal space of the treatment tank is divided into a neutralization reaction chamber, a methanol cooling chamber and a water seal chamber by the partition plates from bottom to top. The neutralization reaction chamber is connected with a gas inlet pipe, an alkali liquor pipe and a liquid discharge pipe, a gas cooling pipe and a fin type heat exchanger are arranged in the methanol cooling chamber, the gas cooling pipe is communicated with the neutralization reaction chamber, the methanol cooling chamber is connected with a top overflow pipe I, and a gas circulating pipe is arranged in the water seal chamber and is communicated with the methanol cooling chamber; the gas circulation pipe and the gas cooling pipe each comprise a bent section, the water seal chamber is connected with a top overflow pipe II, and the top of the water seal chamber is connected with an exhaust pipe and a liquid inlet pipe. The device can be used for removing methyl nitrite, dimethyl oxalate and methanol in the waste gas, so that harmless emission of the waste gas is realized, and the device is suitable for industrial use.

The application discloses a preparation method of chlorophthalic acid, which comprises the following steps: contacting a raw material liquid containing chloro-o-xylene with an oxidant and an oxidation reaction catalyst, and generating an oxidation reaction to prepare the chlorophthalic acid; wherein the oxidant comprises methyl nitrite and oxygen. The method can fully utilize methyl nitrite, which is an important intermediate in a coal-to-ethylene glycol process. The methyl nitrite and the oxygen are used as the oxidant, so that the chloro-o-xylene can be efficiently oxidized to prepare the chlorophthalic acid under mild conditions.