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Method for producing methacrolein and methacrylic acid

A technology for methacrylic acid and methacrolein, applied in chemical instruments and methods, carboxylate preparation, organic chemical methods, etc., can solve the problems of reduced conversion rate of raw materials, decreased catalyst activity, etc., and achieve the effect of increasing yield

Active Publication Date: 2015-07-15
MITSUBISHI CHEM CORP
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] The catalyst used in such a gas-phase contact oxidation reaction is used for a long time, but the activity of the catalyst decreases over time, so the conversion rate of the raw material decreases over time.

Method used

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  • Method for producing methacrolein and methacrylic acid

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0072] (manufacture of catalyst)

[0073] 3000 parts of ammonium paramolybdate was dissolved in 6000 parts of pure water. Next, 74.4 parts of ammonium paratungstate, 138.0 parts of cesium nitrate, 164.4 parts of antimony trioxide, and 198.0 parts of bismuth trioxide were added, stirring this solution, and it heated to 50 degreeC (A liquid). In addition, 1258.8 parts of iron nitrate, 453.0 parts of nickel nitrate, 2719.8 parts of cobalt nitrate, 187.8 parts of lead nitrate and 33.6 parts of 85% phosphoric acid were successively added to 6000 parts of pure water to dissolve, and heated to 30° C. (B liquid). Under stirring, add liquid B to liquid A to obtain an aqueous slurry, which is aged at 90° C. for 2 hours. Then, after heating up to 103 degreeC and concentrating for 1 hour, dry powder was obtained using the spray dryer. The obtained dry powder was fired once at 300° C. for 1 hour, and then fired twice at 510° C. for 3 hours to obtain a fired catalyst powder.

[0074] Aft...

Embodiment 2

[0109] (manufacture of methacrolein and methacrylic acid)

[0110] The reaction tube used in Example 1 was filled with 2150 g of the catalyst produced in Comparative Example 1. Next, a reaction gas composed of 5% by volume of isobutylene (reaction raw material), 10.5% by volume of oxygen, 10% by volume of water vapor, and 74.5% by volume of nitrogen was passed through the catalyst layer at a reaction pressure of 95 kPaG and a contact time of 4.8 seconds. The gas-phase catalytic oxidation of isobutylene was carried out in the same manner as in Example 1 so that the target conversion rate of the raw material was 95%. It should be noted that the reaction start temperature for gas-phase catalytic oxidation of isobutylene was 320°C.

[0111] The time C (hour) from the start of the reaction until the reaction temperature reached TA was 18500 hours, the time D (hour) from the time the reaction temperature reached TA to the end of the reaction was 4000 hours, and C / D was 4.6. It sho...

Embodiment 3

[0113] (manufacture of methacrolein and methacrylic acid)

[0114] The reaction tube used in Example 1 was filled with 2150 g of the catalyst produced in Comparative Example 1. Next, a reaction gas composed of 5% by volume of isobutylene (reaction raw material), 10% by volume of oxygen, 10% by volume of water vapor, and 75% by volume of nitrogen was passed through the catalyst layer at a reaction pressure of 90 kPaG and a contact time of 4.8 seconds. The gas-phase catalytic oxidation of isobutylene was carried out in the same manner as in Example 1 so that the target conversion rate of the raw material was 95%.

[0115] The reaction start temperature for gas-phase catalytic oxidation of isobutylene was 321°C. The time C (hour) until the reaction temperature reached TA was 16,500 hours, the time D (hour) from when the reaction temperature reached TA to the end of the reaction was 6,000 hours, and C / D was 2.8. It should be noted that the time of the whole reaction is 22500 hou...

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Abstract

Provided is a method for producing methacrolein and methacrylic acid, whereby it becomes possible to improve the yields of methacrolein and methacrylic acid. A method for producing methacrolein and methacrylic acid by carrying out the gas-phase catalytic oxidation of at least one raw material selected from the group consisting of isobutylene, TBA and MTBE with molecular oxygen in the presence of a catalyst comprising molybdenum, bismuth and iron using a fixed bed reactor, wherein the reaction starts at a temperature lower than a reaction temperature TA (˚C), the reaction temperature is so controlled that the reaction rate of the raw material can become constant while rising the reaction temperature, and the reaction is terminated at a temperature higher than TA (˚C) in which TA (˚C) represents the boundary temperature of the activation energy of the oxidation reaction, and wherein the ratio of A to B (i.e., A / B) is 0.05 to 0.18 in which A (˚C / hr) represents the average value of the temperature-rising rates employed until the reaction temperature reaches TA and B (˚C / hr) represents the average value of the temperature-rising rates employed at reaction temperatures higher than TA.

Description

technical field [0001] The present invention relates to gas-phase contact of at least one selected from isobutylene, tert-butanol (hereinafter also denoted as TBA) and methyl tert-butyl ether (hereinafter also denoted as MTBE) with molecular oxygen in the presence of a catalyst A method of producing methacrolein and methacrylic acid by oxidation. Background technique [0002] A method of producing methacrolein and methacrylic acid by gas-phase catalytic oxidation of isobutylene, tert-butanol or methyl tert-butyl ether in the presence of a catalyst containing molybdenum, bismuth and iron as essential components is well known and used industrially. This reaction is implemented in the range of 300-400 degreeC, for example using a multitubular fixed-bed reactor. [0003] The catalyst used in such a gas-phase catalytic oxidation reaction is used for a long time, but the activity of the catalyst decreases over time, so the conversion rate of the raw material decreases over time. ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C27/00B01J27/199C07C45/35C07C47/22C07C51/21C07C51/23C07C51/25C07C57/05C07B61/00
CPCB01J2523/00C07C51/252C07C51/23B01J35/023C07C45/37B01J27/199B01J37/0018C07C45/35B01J37/0045C07C47/22C07C57/04B01J2523/54B01J2523/68B01J2523/842B01J2523/15B01J2523/44B01J2523/51B01J2523/53B01J2523/69B01J2523/845B01J2523/847
Inventor 山口哲史辰巳奉正近藤正英藤森祐治
Owner MITSUBISHI CHEM CORP
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