196results about "Nitrous acid preparation ester preparation" patented technology

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 relates to a reaction system for alkyl nitrite and a preparation method for the alkyl nitrite. The preparation method comprises the following steps that: a trickle-bed reactor is adopted and porcelain ring filler is filled into the trickle-bed reactor; liquid added into the reactor forms liquid membranes on the filler; alkyl alcohol is taken as a liquid-phase raw material and nitric monoxide, oxygen and nitrogen are taken as gas-phase raw materials; and gas and liquid phases are reacted in the trickle-bed reactor by means of co-current flow or countercurrent flow under the condition of nitrogen protection so as to generate the alkyl nitrite. The mol ratio of the alkyl alcohol to NO is between 2 to 1 and 7 to 1, and the mol ratio of the NO to O2 is between 4 to 1 and 8 to 1; the reaction temperature is between 40 and 100 DEG C, and the reaction pressure is between 0.1 and 1.0 MPa; and the retention time of continuous feeding of liquid-phase alkyl alcohol in the trickle-bed reactor is between 10 and 500 minutes, and the retention time of continuous feeding of gas phase in the trickle-bed reactor is between 0.02 and 1 minute. The reaction system and the preparation method have the advantages that: the operating condition is mild; the reaction time is short; the conversion rate of the raw materials, and the selectivity and the yield of products are high; and the whole reaction system is convenient for realizing continuous production, etc.

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 relates to a preparation method of a catalyst used in dilute nitric acid treating and alkyl nitrite generating and mainly aims at solving the disadvantages of introducing O2 in the nitrate regeneration process and a series of problems of easy generation of nitric acid, failure in dilute nitric acid treatment, low reaction efficiency, and low nitrite selectivity, and the like in the regeneration process in the prior art. The following technical scheme is adopted: in the presence of an activated carbon coated molecular sieve membrane catalyst, NO reacts with an aqueous solution of alkyl alcohol and nitric acid in a manner of being contacted with the catalyst under the re-circulating conditions in which the reaction temperature is within the range of 60-100 DEG C, a reaction pressure is within the range of 0.28-0.35Mpa, the synthetic gas flow is within the range of 800-1000L/h, the mass fraction of the NO is 8-20%, the mass fraction of the alkyl alcohol is 30-60% in the liquid phase solution and the content of the dilute nitric acid is 1%-10%, due to the reaction, the dilute nitric acid can be completely decomposed into nitrous acid, and the nitrous acid is capable of further reacting with the alkyl alcohol to generate the alkyl nitrite. The catalyst is capable of well being used for catalyzing in the reaction of the dilute nitric acid decomposing and the alkyl nitrite generating with high efficiency, and therefore, the series of problems can be solved. The catalyst can be applied to the regeneration production of the alkyl nitrite in the industry of producing ethylene glycol from coal.

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 synthesis method and equipment of alkyl nitrite. The method mainly includes the following points that: a) the alkyl nitrite regeneration raw materials are the NO in the tail gas generated in production of oxalic acid alkyl ester by coupling reaction of CO and alkyl nitrite, and O2, alkyl alcohol and other raw materials supplemented from the outside; b) the tail gas of the coupling reaction in step a) mainly are unreacted CO, alkyl nitrite, and the NO gas generated by alkyl nitrite decomposition in reaction, O2 is introduced to oxidize most of NO into N2O3; c) the gas mixture in step b) and alkyl alcohol are subjected to esterification regeneration reaction to obtain alkyl nitrite; and d) the by-product nitric acid is inevitably produced in step c), and is also applied to the regeneration process of alkyl nitrite to re-react with the synthesis tail gas so as to generate alkyl nitrite, thus realizing atom economy. The invention also provides equipment for carrying out the reaction. The equipment is composed of three sets of small towers in series connection, i.e. (1) a full mixing tower; (2) an esterification tower; and (3) a nitric acid treatment tower. The method and the equipment provided by the invention have the advantages of mild operation conditions, high regeneration efficiency, good adaptability, strong economical efficiency and the like.

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 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 relates to a method for synthesizing alkyl nitrite to mainly solve the problems of large reactor diameter, high investment cost and high operation cost existing in the prior art. The method comprises the following steps: an oxynitride-containing gas, oxygen and a first flow of alkyl alcohol enter an esterification reactor, and flow through the reactor from top to bottom, gases and liquid flow in parallel, and contact and react with each other to obtain an alkyl alcohol-containing top kettle liquid phase material flow and an alkyl nitrite-containing tower bottom gas phase material flow; the alkyl nitrite-containing tower bottom gas phase material flow is cycled through a cycle approach; and the alkyl nitrite-containing tower bottom gas phase material flow enters the bottom of a washing tower, and is in countercurrent contact with a second flow of alkyl alcohol entering from the top of the washing tower, a washing solution obtained from the bottom of the washing tower enters the top of an esterification reactor, and an alkyl nitrite product flow can be obtained from the top of the washing tower. The method adopting the above technical scheme well solves the problems, and can be used in industrial production of the alkyl nitrite.

The invention discloses a process for producing alkyl nitrite. The process comprises the following step of: based on a nitric oxide and alkyl alcohol as raw materials, preparing alkyl nitrite by recycling by-products formed in the reaction process of the nitric oxide (NOx) and alcoholic solution. The process is applicable under the condition that O2 is involved or not involved, and before the nitric oxide and O2 are in contact reaction, a molar ratio of O2 to NO in the nitric oxide is not more than 0.5 under the condition that O2 is involved. According to the process, nitrogen is basically not consumed, the yield of alkyl nitrite is improved, and the reaction rate is improved; generated nitric acid is concentrated and can be recycled, the solvent is not consumed, wastewater is not generated, and the effects of recycling industrial effluent gas, saving energy, reducing emission and changing wastes into valuable materials are achieved; and meanwhile, the process is applicable under the condition that O2 is involved or not involved.

The invention discloses a preparation method of C1-C4 alkyl nitrite, comprising the following steps: a) oxidizing the gases containing NO to generate a gas mixture basically formed by N2O4, NO2 and NO; b) carrying out chemical balance adjustment on the gas mixture generated in the step a) to obtain a gas mixture basically formed by NO and NO2 with molar ratio of 1:1; and c) reacting the gas mixture generated in the step b) with C1-C4 alkanol to obtain the C1-C4 alkyl nitrite. The invention also provides a reaction device implementing the method, comprising i) a plug flow isothermal reactor, ii) a perfectly mixed isothermal reactor and iii) an esterification packed tower. The invention has the advantages of moderate operation conditions, short reaction time, high product purity, strong suitability to the raw materials, etc.

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 present invention relates to nitric oxide releasing prodrugs of known drugs or therapeutic agents wherein the drug or therapeutic agents contain at least one carboxylic acid group. The invention also relates to processes for the preparation of these nitric oxide releasing prodrugs, to pharmaceutical compositions containing them and to methods of using these produgs.