176 results about "Methyl nitrite" patented technology

The invention relates to a catalyst for synthesizing oxalic ester and a preparation method thereof. The catalyst contains active components of palladium and lanthanum which respectively account for 0.3-1.5 percent and 0.01-8 percent of the weight of a carrier, and the carrier is Alpha-Al2O3. The preparation method comprises the following steps: placing the Alpha-Al2O3 into alkaline solution, and processing the Alpha-Al2O3 in a high-pressure kettle under a temperature of 150-350 DEG C; washing the Alpha-Al2O3 with distilled water to neutral; drying the Alpha-Al2O3 under the temperature of 100-200 DEG C; dipping the Alpha-Al2O3 in solution with the concentration of lanthanum being 0.003-0.02 M, drying and baking; and dipping the Alpha-Al2O3 in solution with the concentration of palladium being 0.003-0.02 M, drying and baking under a temperature of 300-700 DEG C. The catalyst is applied to a reaction for synthesizing dimethyl oxalate by carbon monoxide and methyl nitrite and has the advantages of higher reacting activity and selectivity, long service life, stable reaction and easy control; and the space time yield of the dimethyl oxalate is 830g/L.h-1130g/L.h.

The invention relates to a technology and a device system for producing dimethyl oxalate by high-pressure carbonylation of industrial synthesis gases and producing ethylene glycol through dimethyl oxalate hydrogenation. The technology comprises the following steps: adopting industrial NO, O2 and methanol as raw materials for an esterification reaction to produce methyl nitrite; adopting industrial CO and methyl nitrite for a carbonylation reaction in a plate reactor to produce carbonylation products, which mainly include dimethyl oxalate and dimethyl carbonate; separating the carbonylation products to obtain dimethyl carbonate products; subsequently adding hydrogen into dimethyl oxalate in the plate reactor to produce ethylene glycol products; conducting the coupling recovery treatment on waste acids in the esterification reaction and purge gases in the carbonylation reaction for recycling. The device system comprises an esterification reaction system, a carbonylation reaction system, a coupling recovery system for purge gases and waste acids and a hydrogenation reaction system. The technology has the characteristic that device consumption is remarkably reduced, and particularly the nitric acid waste liquid recycling and purge gas recycling technologies as well as the separation technologies thereof are highly coupled; recycling of the raw materials in reaction waste gases is realized, and the effect is remarkable.

The invention provides a supported palladium-based catalyst and a preparation method and an application thereof. The supported palladium-based catalyst comprises an active ingredient and a carrier, wherein the active ingredient is a palladium-based compound; the carrier is selected from at least one of aluminum oxide, silicon oxide, magnesium oxide, zinc oxide, zirconium oxide, titanium dioxide, metal organic framework compound, activated carbon, molecular sieve, carbon nanotube, and graphene. The supported palladium-based catalyst is applied to the reaction of methyl nitrite vapor-phase carbonylation preparing dimethyl carbonate, and has the advantages that the catalytic activity is high, the product selectivity is high, and the service life is long.

The invention provides a process device for producing methyl nitrite. The process device comprises a reactive distillation tower, a pre-reactor, a pre-heater, a reboiler, a methanol recovering and buffering groove and an acid water groove, wherein a condenser is arranged in reactive distillation tower; the pre-reactor, the pre-heater, the reactive distillation tower, the reboiler and the methanol recovering and buffering groove are connected in sequence; the input end of the pre-reactor is connected with an NO recycle gas pipeline and an oxygen pipeline in a carbonylation reaction process respectively; the oxygen pipeline is provided with an air separating device; the two ends of a subcooler are communicated with the condenser and the reactive distillation tower respectively; one end of the subcooler is connected with a carbonylation reaction system; the input port of the acid water groove is connected with an acid water pipe and a process soft water pipe respectively; and a first circulation pump and a second circulation pump are arranged among the methanol recovering and buffering groove, the acid water groove and the reactive distillation tower respectively. The process device is simplified, production equipment is saved, the production cost is lowered, and the process device can be better applied to an ethylene glycol process.

The invention relates to a method and equipment for continuously producing methyl nitrite in large scale. The method for producing methyl nitrite comprises the following steps of: carrying out the esterification of methanol, oxygen and a nitrogen oxide in an esterification reaction tower to obtain methyl nitrite; circulating and returning the liquid flow from the outlet at the bottom of the esterification reaction tower to the top of the tower, leading the gas flow from the outlet at the bottom of the esterification reaction tower to a purification tower and washing the gas from the bottom of the esterification tower by countercurrent contact with an organic purifier; drying the gas from the top of the purification tower in a dryer to obtain methyl-nitrite-containing dry gas; and leading liquid at the bottom of the purification tower to a recovery tower, and separating a recovery purifier. The methyl nitrite produced by the method can be directly used to prepare dimethyl oxalate through oxidization, carbonylation and coupling reaction with CO. Compared with the conventional production process, the method for producing methyl nitrite has the characteristics of economy, environment friendliness, less waste water and the like.

The invention belongs to the technical field of the production of dimethyl oxalate, and particularly relates to a process method and a device for regenerating methyl nitrite in the production of the dimethyl oxalate. In the method, the utilization rate of nitric oxide in the regenerative process is improved, and the using amount of methanol is reduced. The device comprises a rotary filler bed, wherein a gas inlet of the rotary filler bed is connected with sources of nitrogen, oxygen and nitric oxide respectively, a liquid inlet is connected with a methanol storage tank, a liquid outlet is connected with an inlet of a methanol-water mixture storage tank, and a gas outlet is connected with a condenser I. The process method comprises the following steps of: opening the rotary filler bed, so that the nitric oxide, the nitrogen and the oxygen are contacted and reacted with absolute methanol in the rotary filler bed to form a gas phase and a liquid phase; and discharging the gas phase, condensing, and allowing the liquid phase to flow into the methanol-water mixture storage tank. The process method has the advantages that: the process reaction efficiency is high; all NO is used efficiently; and the equipment has a compact structure and small volume and requires a small investment. The equipment has the advantages of making operation easy, along with simple structure, small energy consumption, simple flow, convenience for starting and stopping and the like.

The invention discloses a process for producing dimethyl carbonate which comprises, mixing HCl with the gaseous mixture of carbon monoxide and methyl nitrite, then entering auxiliary reaction area, mixing the product yield of the subsidiary reaction zone with the gaseous mixture of carbon monoxide raw material gas and methyl nitrite, entering main reaction zone, condensing and absorbing the product yield of the main reaction zone, separating and rectifcating the condensate liquid, thus obtaining the dimethyl carbonate product, while the non-condensed gas, oxygen, nitrogen monoxide reacting with methanol and obtaining and methyl nitrite for use by the subsidiary reaction zone and the main reaction zone. The process provided by the invention can sustain catalytic activity, extend period of catalyst use, and avoid the use of hypertoxic methyl chloroformate.

The invention discloses a catalyst for synthesizing dimethyl carbonate through methyl nitrite carbonylation and a preparation method of the catalyst. A main active component of the catalyst is palladium, auxiliary active components of the catalyst are Cu, K and organic ligand, carriers of the catalyst are NaY, NaX and Nabeta type molecular sieves, and the catalyst belongs to chloride-free system catalysts. The catalyst has the advantages that the organic ligand is introduced, the active components and the organic ligand can be properly combined by optimizing preparation conditions, on the one hand, the electron cloud density of the main active component Pd can be increased, activation of CO is promoted, and therefore the activity of the catalyst is improved; on the other hand, due to the existence of the organic ligand, migration and agglomeration of the active components in the reaction process can be effectively inhibited, and the stability of the catalyst can be improved.

The invention relates to a regeneration process and a regeneration device system of methyl nitrite in a process for preparation of ethylene glycol from a synthesis gas, the regeneration process comprises the following steps: (1) methyl nitrite regeneration, to be more specific, a liquid containing methanol and nitric acid and a gas containing nitrogen oxides from a methyl nitrite synthesis reactor are introduced into a methyl nitrite regeneration tower for reaction to obtain methyl nitrite; and (2) methyl nitrite stripping recovery, to be more specific, a methyl nitrite regeneration tower kettle components and a gas or gases selected from one or more of N2, CO2, CH4, CO and the nitrogen oxides are introduced into a methyl nitrite regeneration stripping tower for stripping for recovery of the methyl nitrite dissolved in the methanol. The regeneration process reduces the consumption of the nitric acid in the process for preparation of the ethylene glycol from the synthesis gas, the nitric acid produced by side reaction is economically and efficiently recovered, and the problem that a methanol solution dissolves the methyl nitrite can be solved.

The invention discloses a method for preparing methyl nitrite through catalyzing dilute nitric acid. The method comprises the following steps of using dilute nitric acid and methanol as substrates; under the effect of a nitrogen-containing carbon-based catalyst, one-step reaction and high-selectivity conversion are performed to obtain the methyl nitrite. A continuous fixed bed reactor is used; under the effect of the nitrogen-containing carbon-based catalyst, the nitric acid is promoted to be reduced into methyl nitrite for reaction; the nitrogen ingredients in the catalyst are favorable for the proceeding of the esterification process. The catalyst has high dilute nitric acid conversion efficiency.

The invention provides a methyl nitrite recovery method during a CO coupling dimethyl oxalate synthesis process. A gas-phase material containing methyl nitrite is delivered into an upper-middle part of a rectification tower; a liquid-phase material and a gas-phase material containing methyl nitrite are delivered into the rectification tower; a tower-top material contains methyl nitrite, and a tower-kettle material contains methanol and water; a tower plate number of the rectification tower is 10-50, the tower kettle temperature is 50 DEG C to 200 DEG C, a tower top temperature is -10 DEG C to 100 DEG C, a reflux ratio is 0.2-3.0, and an operation pressure is 50-400kPa. With the methyl nitrite recovery method provided by the invention, methyl nitrite loss can be reduced, methyl nitrite utilization rate can be improved, and cost can be reduced.

The invention relates to a method and a device for treating waste gas and waste liquid in ethylene glycol production. The method comprises the following steps of: heating waste gas generated in ethylene glycol production; feeding the heated waste gas into a reactor, reacting methyl nitrite in the waste gas to generate methanol in the presence of a catalyst, and interacting nitric oxide, hydrogen and carbon monoxide in the waste gas to generate nitrogen, water, carbon dioxide and ammonia; feeding the generated waste liquid into an absorption tower in ethylene glycol production, allowing the waste liquid to enter from the upper part of the absorption tower, allowing the reacted gas to enter from the lower part of the absorption tower, fully absorbing the gas through the waste liquid, neutralizing the waste liquid which absorbs the gas through an alkali liquor, and discharging the gas from the absorption tower for gasification, and adding the gasified gas into coal slurry for treatment; and discharging the residual gas into the atmosphere from the top of the absorption tower. The device comprises a heat exchanger, a heater, a reactor, a cooler, an absorption tower and a waste liquid cooler. The environmental pollution problems in the waste gas and waste liquid generated in the industrial ethylene glycol production in the conventional synthesis gas production are solved.

The invention relates to a method for preparing oxalate by using a CO gaseous phase process, which mainly solves the technical problem of low utilization rate of nitric oxides or nitrite in the prior art. The method comprises the following steps of: a, enabling a nitric oxide mixture, C2-C4 alkane alcohol and air to enter a reactor 1 to generate an effluent I containing C2-C4 alkyl nitrite; separating the effluent to obtain a non-condensable gas effluent II and a non-condensable gas effluent III; b, enabling the effluent III and a first path of CO gas to enter a coupling reactor I to generate an oxalate liquid phase effluent IV and an NO-containing gas phase effluent V; c, enabling the effluent V and methane and oxygen to enter a reactor II to generate an effluent VI containing methyl nitrite, separating to obtain a methyl nitrite effluent VII and then enabling the methyl nitrite effluent VII and a second path of CO gas to enter a coupling reactor II to react to obtain a dimethyl oxalate effluent VIII and an NO-containing gas phase effluent IX; d, returning the effluent IX to be mixed with the effluent V for circular use; and e, separating the dimethyl oxalate effluent VIII to obtain a dimethyl oxalate product I. The technical scheme for obtaining the oxalate product II by separating the oxalate liquid phase effluent IV better solves the problem and can be used in the industrialized production for preparing the oxalate by using the CO gas phase process.

The invention discloses a methyl nitrite regeneration method, and is used for solving the problems of low regeneration rate of methyl nitrite, poor operational stability of a system caused by improper side reaction control, increase of operating cost and the like. The methyl nitrite regeneration method comprises the following steps: forming recycled gas containing 5-20% of nitric oxide after synthesis of methyl nitrite and carbon monoxide carbonyl, and entering the recycled gas to a methyl nitrite regeneration reactor in two parts, wherein a small part of recycled gas enters the lower section of the regeneration reactor from the bottom, the rest part of recycled gas and supplementing oxygen gas enter the upper section of the regeneration reactor from the middle part together; spraying fresh methyl alcohol into the tower top of the regeneration reactor, discharging methyl nitrite-containing gas from the tower top, pressurizing tower bottoms led out from the tower by using a pump and entering the tower bottoms to the lower section of the regeneration reactor from the middle part of the regeneration reactor; arranging a reboiler on the tower of the regeneration reactor, filling the lower section of the regeneration reactor with a catalyst, and arranging stuffing and/or a tower plate on the upper section of the regeneration reactor. The methyl nitrite regeneration method is simple in process, low in equipment investment and operating cost and high in regeneration rate of methyl nitrite and can be used for effectively solving the side reaction problem.

The invention provides a dimethyl oxalate production method with a byproduct (dimethyl carbonate). The method comprises the following steps: (a) introducing reaction materials containing CO and methyl nitrite into a coupling reactor, and carrying out reactions in the presence of a platinum family metal catalyst to obtain a gas phase material flow containing dimethyl oxalate and dimethyl carbonate; (b) introducing the gas phase material flow containing dimethyl oxalate and dimethyl carbonate into an ester separation tower to contact with a methanol material flow from the top of the ester separation tower and an extracting agent material flow containing oxalic acid from the middle of the ester separation tower in a countercurrent contact mode, obtaining crude methanol from the top of the ester separation tower, and obtaining a mixture containing dimethyl oxalate and dimethyl carbonate from the bottom of the ester separation tower; and (c) introducing the mixture into a dimethyl oxalate refining tower, obtaining a dimethyl carbonate product from the top of the dimethyl oxalate refining tower, and obtaining a dimethyl oxalate product from the bottom of the dimethyl oxalate refining tower; wherein the gas phase material flow containing dimethyl oxalate and dimethyl carbonate is not cooled after being introduced into the ester separation tower.

The present invention provides a production apparatus and a production method for methyl nitrite. The apparatus comprises: a belt conveying device, a dissolving stirring tank, a first storage tank for storing sodium nitrite, a reactor, a second storage tank for storing methanol, a third storage tank for storing nitric acid, and a rectification tower. The production method comprises that: three solutions of sodium nitrite, methanol and nitric acid are added to the reactor; complete and uniform mixing is performed under stirring to carry out a reaction; the material outflowing from the reactor enters the rectification tower through adjustment valve control, and is subjected to gas-liquid two phase separation through the rectification tower; and the gas and the liquid are respectively discharged from a gas outlet and a sodium nitrate solution outlet, and the sodium nitrate solution discharged from the bottom of the rectification tower is conveyed to a sodium nitrate drying crystallization device to be adopted as a byproduct. According to the present invention, the conventional concept of multi-reaction kettle intermittent switching operation is broken through, continuous and uninterrupted production is achieved, characteristics of simple and short process route, safe operation and reasonable design are provided, and good economic benefits, social benefits and environmental protection benefits are provided.

The invention belongs to the technical field of catalyst preparation, and particularly relates to a preparation method of a modified molecular sieve loaded Pd catalyst and application thereof in synthesis of dimethyl carbonate by a gas phase process. The carrier of the catalyst is a modified FAU or EMT molecular sieve, main active components are zero-valent palladium (Pd) and valence state Pd, themass fraction of Pd in the catalyst is 0.1%-2.5%, and the average particle size of Pd particles is 0.2-15 nanometers. The catalyst is applied to a reaction for synthesizing dimethyl carbonate from carbon monoxide and methyl nitrite by a low-pressure gas phase process, solves the problems of equipment corrosion and inactivation caused by a traditional chlorine-containing catalyst, and is a high-performance catalyst which is high in stability, selectivity and conversion rate, resistant to sintering, free of chlorine and adjustable in Pd nanoparticle size. The preparation method of the catalystis simple, low in equipment requirement and low in production cost, is suitable for large-scale production, and has certain industrial application prospect.

The invention discloses a catalyst for preparing methyl nitrite by reducing dilute nitric acid through methanol and preparation thereof. The catalyst is characterized in that SiO2 and Al2O3 pellets with the particle sizes being 5-20 meshes are adopted as carriers, transition metal oxides with oxidation reduction are taken as active components, carbon deposits are taken as auxiliary active components, the active components are highly dispersed on the carriers, the content range is 0.5-5wt%, and the carriers are wrapped by the auxiliary active components. The transition metal oxides with oxidation reduction are one or two of Mn3O4, CeO2, ZrO2, Co3O4, MoO3 and V2O5. The precursors of the carbon deposits are one of glucose and saccharose. According to the catalyst, the carriers have the advantages of high strength and wear resistance; an auxiliary catalyst has the advantage of high specific surface, the active components can be highly dispersed on the carriers due to the assistance of the auxiliary catalyst, so that the high activity is shown in the process of preparing methyl nitrite by reducing dilute nitric acid through methanol.

The invention provides a catalyst for synthesizing dimethyl carbonate through catalytic coupling of carbon monoxide as well as a preparation method and application thereof. The catalyst comprises a modified composite oxide carrier, a metal palladium active component and a transition metal additive, wherein the modified composite oxide carrier is VIB group element modified gamma-aluminum oxide, themetal palladium element in the metal palladium active component accounts for 0.3-1.5% of the weight of the gamma-aluminum oxide, and the transition metal element in the transition metal additive accounts for 0.5-3.5% of the weight of the gamma-aluminum oxide. The catalyst disclosed by the invention can be applied to gas-phase synthesis of dimethyl carbonate from CO and methyl nitrite under low-temperature and low-pressure conditions, has relatively high low-temperature activity, selectivity and space-time yield, is stable in reaction performance, and can operate for a relatively long time.

The invention provides a catalyst used for synthesis of dimethyl oxalate and a preparation method thereof. The catalyst comprises an active component of palladium and a carrier of spherical alpha-Al2O3, wherein the loading amount of palladium accounts for 0.1 to 0.5% of the mass of the carrier; palladium particles have an average particle size of 2.5 to 3 nm and a dispersity of 34 to 37%; and the spherical alpha-Al2O3 has a particle size of 1 to 3 mm and a specific surface area of 0.5 to 10 m2/g. The catalyst is prepared through the following steps: dissolving palladium acetate in an organic solvent so as to prepare an impregnating solution, then impregnating the spherical alpha-Al2O3 in the impregnating solution for 12 to 24 hours, and carrying out drying and calcining. According to the invention, by using the organic solvent as the impregnating solution, the palladium particles on the carrier have high dispersity and small particle size. Thus, the catalyst has high reaction activity and long service life in reaction of synthesizing dimethyl oxalate from carbon monoxide and methyl nitrite.

The invention discloses a supported catalyst applicable to reaction for synthesizing methyl formate by formylating methyl nitrite. The supported catalyst comprises a palladium cyanide active component, a carrier and an optional accessory ingredient. According to the mass of the carrier, the percentage of the active component palladium cyanide is 0.01-2%, and the percentage of the accessory ingredient is less than or equal to 20%. The invention also discloses a preparation method of the catalyst applicable to reaction for synthesizing methyl formate by formylating methyl nitrite. The preparation method comprises the following steps: optionally dipping the carrier into water or ethanol solution of an accessory ingredient precursor, standing, drying and roasting; then dipping the carrier into water or ethanol solution of a palladium precursor, evenly stirring and evenly dispersing the carrier in a palladium precursor solution; carrying out ultrasound treatment under the heating condition until a solvent of the solution is volatilized to be dry, and evenly absorbing the palladium precursor on the surface of the carrier; drying and roasting an obtained absorption sample; and then reducing in the atmosphere of high-purity hydrogen to obtain a supported type palladium cyanide catalyst.

The invention discloses a nitric acid reduction method in the preparation process of methyl nitrite. The circulating tail gas and the bottom liquid of the esterification tower from the nitric oxide circulating compressor are respectively heated and then sent to the nitric acid reduction tower. The reaction is carried out from top to bottom. The vapor phase at the outlet of the reduction tower bottom is cooled and then enters the discharge flash tank at the bottom of the nitric acid reduction tower. The liquid phase is pumped and then sent to the top of the stripping tower. The carbon monoxide gas is in countercurrent contact, the methyl nitrite gas and nitrogen monoxide gas in the liquid phase are stripped, the vapor phase at the top of the stripping tower and the cooled vapor phase at the top of the reduction tower enter the flash tank together, and are separated by flash evaporation Finally, the gas phase returns to the cycle gas compressor, and the liquid phase is vaporized before tail gas treatment.