15 results about "Methyl nitrite" patented technology

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 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 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 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.

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 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.