Method for synthesizing oxalic ester by CO coupling

A technology of oxalate and nitrite, applied in chemical instruments and methods, carbon monoxide or formate reaction preparation, organic chemistry, etc., can solve the problem of large radial temperature difference, catalyst overheating, and the selectivity of target product oxalate Low-level problems, to achieve the effect of good technical effects

Active Publication Date: 2011-03-30
CHINA PETROLEUM & CHEM CORP +1
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Problems solved by technology

[0009] The technical problem to be solved by the present invention is that the temperature difference in the radial direction of the reactor in the prior art is large, which easily causes the catalyst to overheat, deactivate, and the selectivity of the target product oxalate is low. A new CO coupling unit is provided. A method for forming oxalate, which has the characteristics of small temperature difference in the radial direction of the reactor, high conversion rate of raw materials, good selectivity of oxalate, etc.

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  • Method for synthesizing oxalic ester by CO coupling

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Embodiment 1

[0019] according to figure 1 , The inner diameter of the tubular fixed-bed reactor for CO coupling synthesis of dimethyl oxalate is 2 meters. The palladium-containing catalyst uses alumina as a carrier, and only supports palladium, and the amount of oxides selected from palladium is 0.8% by weight based on the weight of elemental palladium. The cooling medium is CO gas. The molar ratio of CO to methyl nitrite entering the reactor was 1.2:1. according to figure 1 In the process, the raw material gas containing CO and methyl nitrite enters the reactor through the raw material inlet. Under the conditions of the reaction temperature of 110 ° C, the reaction pressure of 0.1 MPa, and the contact time of 1 second, it is mixed with the catalyst bed outside the tube. The palladium-containing catalyst in the layer contacts and reacts, and the heat of reaction is absorbed by the cooling gas in the tube to generate a reaction effluent containing dimethyl oxalate. After the CO-containi...

Embodiment 2

[0021] according to figure 1 , The inner diameter of the tubular fixed-bed reactor for CO coupling synthesis of dimethyl oxalate is 2.5 meters. The palladium-containing catalyst is Pd-Ni / Al 2 o 3 Catalyst, based on the weight of elemental palladium, the amount of oxides selected from metal palladium and palladium is 0.5% by weight, the auxiliary agent Ni is based on the weight of elemental nickel, and the amount of oxides selected from nickel is 0.8% by weight %. The cooling medium is a mixed gas of methyl nitrite and CO. The molar ratio of CO to methyl nitrite entering the reactor was 1.5:1. according to figure 1 In the process, the raw material gas containing CO and methyl nitrite enters the reactor through the raw material inlet. Under the conditions of the reaction temperature of 140 ° C, the reaction pressure of 0.5 MPa, and the contact time of 2 seconds, it is mixed with the catalyst bed outside the tube. The palladium-containing catalyst in the layer contacts and ...

Embodiment 3

[0023] according to figure 1 , The inner diameter of the tubular fixed-bed reactor for CO coupling synthesis of diethyl oxalate is 2.5 meters. The palladium-containing catalyst is Pd-Ce / Al 2 o 3 The catalyst is based on the weight of elemental palladium, and the amount of the oxide selected from palladium is 1% by weight, and the auxiliary agent Ce is based on the weight of elemental cerium, and the amount selected from the oxide of cerium is 1.2% by weight. The cooling medium is ethyl nitrite. The molar ratio of CO and ethyl nitrite entering the reactor was 2:1. according to figure 1 In the process, the raw material gas containing CO and ethyl nitrite enters the reactor through the raw material inlet. Under the conditions of the reaction temperature of 120 ° C, the reaction pressure of 1.0 MPa, and the contact time of 3 seconds, it is mixed with the catalyst bed outside the tube. The palladium-containing catalyst in the layer contacts and reacts, and the heat of reaction...

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Abstract

The invention relates to a method for synthesizing oxalic ester by CO coupling, which mainly solves the problems that the temperature difference in a reactor is large, temperature runaway and inactivation of the catalyst can be caused easily, and the selectivity of the target product oxalic ester is low. The invention adopts the technical scheme of taking nitrous acid ester and CO as raw materials, wherein the mol ratio of the CO to the nitrous acid ester is 1-5:1, and taking at least one of the nitrous acid ester, the CO or water as a cooling medium, and comprising the following steps: underthe conditions that the reaction temperature is 60 DEG C-160 DEG C, the reaction pressure is 0-1.5MPa, and the contact time is 0.5-6 seconds, the cooling medium passes through tubes in a tube-type fixed bed reactor, a catalyst bed is positioned outside the tubes, and after raw gas enters the reactor, the raw gas contacts with the palladium catalyst outside the tubes and reacts to generate the oxalic ester, wherein the flow direction of the cooling medium is in the same or reverse direction of the flow direction of the raw gas. The technical scheme better solves the problems and can be used for the industrial production for increasing the yield of the oxalic ester.

Description

technical field [0001] The present invention relates to a kind of method of CO coupling synthesizing oxalate, more specifically, relate to a kind of gas-phase method CO and methyl nitrite or ethyl nitrite in the shell-and-tube fixed-bed reactor of internal shell-and-tube heat exchange Method for producing dimethyl oxalate or diethyl oxalate by ester reaction. Background technique [0002] Oxalate is an important chemical raw material, which can be used to prepare oxalic acid, ethylene glycol, carbonate, oxamide, intermediates of drugs and dyes, plastic accelerators and solvents, etc. [0003] The traditional production route of oxalate is the method of esterification and dehydration of oxalic acid and alcohol with toluene as the dehydrating agent. The production process is long, the energy is high, the pollution is serious, and the cost is high. It is urgent to find a new process route. The gas-phase catalyzed synthesis of oxalate from CO and nitrite opens up a new and impo...

Claims

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Application Information

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IPC IPC(8): C07C69/36C07C67/36B01J8/02
Inventor 孙凤侠刘俊涛王万民蒯骏
Owner CHINA PETROLEUM & CHEM CORP
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