Process method for preparing maleic anhydride from n-butane by oxidation

A process method, technology of n-butane, applied in the field of reaction process of n-butane oxidation to maleic anhydride, can solve the problems of reducing effective volume of reactor, increasing product yield, reducing production efficiency, etc. High anhydride yield and the effect of overcoming temperature drop

Active Publication Date: 2018-06-01
CHINA PETROLEUM & CHEM CORP +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0013] USP4,855,459 proposes a method for preparing maleic anhydride by oxidation of n-butane, which is carried out by diluting and packing inert silica-alumina balls and catalysts, and reducing the hot spots of reaction by diluting and packing at the hot spots of the reaction tube. temperature, to improve the selectivity of maleic anhydride, the purpose of increasing the yield of maleic anhydride, and at the same time the stability period of the catalyst has been extended, but the unfavorable factor is the addition of inert materials, which reduces the effective volume of the reactor and also reduces the production efficiency
[0014] In the existing fixed-bed n-butane oxidation to maleic anhydride technology, catalysts with different activities are loaded in the reactor along the direction of reactant flow, so that when the catalyst is loaded, the catalytic activity changes along the feed direction according to the reaction requirements, so as to realize the oxidation The method of controlling the reaction, realizing the recycling of reaction tail gas, and increasing the product yield has not been reported so far

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  • Process method for preparing maleic anhydride from n-butane by oxidation
  • Process method for preparing maleic anhydride from n-butane by oxidation
  • Process method for preparing maleic anhydride from n-butane by oxidation

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preparation example Construction

[0047] (2) Preparation of vanadium phosphorus oxygen catalyst

[0048] The vanadium phosphorus oxide obtained in step (1) is first shaped, and the shape of the obtained vanadium phosphorus oxygen catalyst can be a compressed tablet, a spherical shape, an extruded rod, etc., and the phase of the obtained catalyst precursor is (VOHPO 4 0.5H 2 o).

[0049] (3) Activation treatment of vanadium phosphorus oxygen catalyst

[0050] The shaped catalyst precursor in step (2) is activated in an atmosphere of nitrogen or inert gas, or in an atmosphere of n-butane / air mixture, to obtain an activated vanadium-phosphorus-oxygen catalyst.

[0051] Wherein in step (3), the activation temperature is generally 350-450°C, preferably 375-425°C; the activation time is generally 5-40 hours, preferably 12-20 hours. The volume space velocity of nitrogen, inert gas or n-butane / air mixed atmosphere is generally 100-2000h -1 , preferably 500~1000h -1 .

[0052] In the present invention, the prepar...

Embodiment 1

[0057] exist figure 1 Add 442.95 kg of isobutanol, 29.53 kg of vanadium pentoxide, 0.3 kg of ferric nitrate hexahydrate, and 0.5 kg of zirconium nitrate into the reaction kettle shown with a stirring device and a reflux condensing device. High reaction temperature and kept at 100±2°C, carry out reflux reaction, keep reflux time for 4 hours, then add 47.50kg of phosphoric acid with a concentration of 85%, the phosphorus / vanadium molar ratio is 1.27, continue to reflux for 8 hours, and the reaction ends. After the reaction solution was cooled to room temperature, it was vacuum filtered, and the filter cake was rinsed with a small amount of isobutanol three times, then the filter cake was placed in an enamel tray and dried naturally at room temperature, dried in an oven at 100°C for 8 hours, and finally dried in a muffle furnace. Calcined at 250°C for 5 hours to obtain a dark brown catalyst precursor.

[0058] Add the catalyst precursor prepared above to graphite powder with a m...

Embodiment 2

[0062] exist figure 1 Add 442.95 kg of isobutanol, 29.53 kg of vanadium pentoxide, 0.3 kg of ferric nitrate hexahydrate, and 0.5 kg of zirconium nitrate into the reaction kettle shown with a stirring device and a reflux condensing device. High reaction temperature and kept at 100±2°C, carry out reflux reaction, keep reflux time for 4 hours, then add 44.13kg of phosphoric acid with a concentration of 85%, the phosphorus / vanadium molar ratio is 1.18, continue to reflux for 8 hours, and the reaction ends. After the reaction solution was cooled to room temperature, it was vacuum filtered, and the filter cake was rinsed three times with a small amount of isobutanol to complete the reaction. The filter cake was put into an enamel dish and air-dried at room temperature, dried in an oven at 100°C for 8 hours, and finally calcined in a muffle furnace at 250°C for 5 hours to obtain a dark brown catalyst precursor.

[0063] Add the catalyst precursor prepared above to graphite powder wi...

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Abstract

The invention discloses a process method for preparing maleic anhydride from n-butane by oxidation. N-butane and air are mixed with circulating tail gas, and obtained mixed reaction gas flows in parallel through two or more reaction zones connected in series sequentially, and is contacted with a vanadium phosphorus oxide catalyst for reaction under the oxidation reaction condition, wherein each reaction zone comprises two or more of catalyst beds except the most downstream reaction zone, according to the contact sequence with the mixed reaction gas, the P / V molar ratio of the catalyst in the downstream reaction zone is lower than that of the catalyst in the upstream reaction zone, and the P / V molar ratio of the downstream catalyst bed is higher than that of the upstream catalyst bed in allthe reaction zones except the most downstream reaction zone. With the method, activity of the catalyst can be fully played, especially in the tail gas recycling process, the influence from the decrease of conversion rate due to the decrease of oxygen content of raw materials can be better avoided, reaction hot spots are reduced, and product selectivity is improved.

Description

technical field [0001] The invention relates to a process for preparing maleic anhydride by n-butane oxidation, which can be used in the reaction process of n-butane oxidation for maleic anhydride using a fixed bed process. Background technique [0002] Maleic anhydride, also known as maleic anhydride, is an important organic chemical raw material and the third largest organic anhydride in the world after phthalic anhydride and acetic anhydride. It is widely used in petrochemical, food processing, and pharmaceutical industries. , Building materials and other industries. Its specific applications include the manufacture of unsaturated polyester resins, alkyd resins, maleic acid (maleic acid), fumaric acid (fumaric acid), as well as pesticides, coatings, glass fiber reinforced plastics, lubricating oil additives, paper chemistry Product additives, surfactants, etc. The advent of the new method of maleic anhydride esterification and low-pressure hydrogenation to produce 1,4-b...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07D307/60
CPCC07D307/60
Inventor 王海波程谨宋丽芝勾连科侯学伟刘新宇
Owner CHINA PETROLEUM & CHEM CORP
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