Carbonylation method for synthesizing acetic acid by combining rhodium and iridium

A technology for chemical synthesis and rhodium compound, applied in the field of oxo-synthesis of acetic acid by rhodium-iridium combined use, can solve problems such as low activity, achieve the effects of high activity, reduce catalyst cost, and improve catalytic activity

Inactive Publication Date: 2011-06-01
SHANGHAI HUAYI ENERGY CHEM
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0005] In patent FR9303733, it is reported that rhodium-iridium combined catalyst system carbonylation prepares carboxylic acid or corresponding ester, under certain water content and methyl iodide concentration, the effect of rhodium and iridium combined use is better than the effect of single use, but due to Without adding other accelerators, the activity of the reaction is relatively low

Method used

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  • Carbonylation method for synthesizing acetic acid by combining rhodium and iridium
  • Carbonylation method for synthesizing acetic acid by combining rhodium and iridium
  • Carbonylation method for synthesizing acetic acid by combining rhodium and iridium

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0027] Add Ir(OAc) to a 250ml zirconium autoclave equipped with a pressure gauge under air atmosphere 3 231mg, the concentration of iridium in the system is 900ppm, RhI 3 630mg, the concentration of rhodium in the system is 1000ppm, ZnI 2 0.934mg, Ir:Zn=1:5 (molar ratio), iodomethane 8.75g, initial concentration is 7%, distilled water 8.75g, initial concentration is 7%, methyl acetate 37.5g, initial concentration is 30% , the rest is 70.0g of acetic acid solvent, keeping the reaction temperature at 190°C and the reaction pressure at 30bar, and reacting to a certain stage of quenching. At this time, the weight ratio of methyl acetate in the reaction solution is 15%.

[0028] The difference between embodiment 2-5 and embodiment 1 is only: the concentration of rhodium in the system is different. See Table 1 for the comparative experiments of changing the rhodium content.

[0029] Table 1

[0030]

Embodiment 6

[0032] Add Ir(OAc) to a 250ml zirconium autoclave equipped with a pressure gauge under air atmosphere 3 77mg, the concentration of iridium in the system is 300ppm, RhI 3 189mg, the concentration of rhodium in the system is 300ppm, ZnI 2 0.311mg, Ir: Zn=1:5 (molar ratio), iodomethane 8.75g, initial concentration is 7%, distilled water 8.75g, initial concentration is 7%, methyl acetate 37.5g, initial concentration is 30% , the rest is 70.0g of acetic acid solvent, keeping the reaction temperature at 190°C and the reaction pressure at 30bar, and reacting to a certain stage of quenching. At this time, the weight ratio of methyl acetate in the reaction solution is 15%.

[0033] The only difference between Examples 7-10 and Example 6 is that the concentration of iridium in the system is different. See Table 2 for the comparative experiments of changing the iridium content.

[0034] Table 2

[0035]

Embodiment 11

[0037] Add iridium acetate (iridium content 48%) 231mg in the zirconium material autoclave that pressure gauge is housed in 250ml under air atmosphere, the content of iridium in the system is 900ppm, iodomethane 8.75g, initial mass concentration is 7%, distilled water 8.75g, initial mass concentration 7%, methyl acetate 37.5g, initial mass concentration is 30%, the rest is 70.0g acetic acid solvent, keep reaction temperature 190 ℃, reaction pressure 30bar, react until the weight ratio of methyl acetate is 15 %, the corresponding carbonylation rate is 6mol / Lh.

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Abstract

The invention discloses a carbonylation method for synthesizing acetic acid by combining rhodium and iridium, which comprises the following step: reacting a liquid-phase medium including methanol, methyl acetate, acetic acid and water with carbon monoxide to generate acetic acid, wherein the catalysis system used in the reaction is as follows: rhodium compounds and iridium compounds of group VIII are used as main catalysts, iodomethane is used as a catalyst promoter, and zinc salt is used as stabilizer. Because of the stabilizing effect of the zinc salt, the rhodium compounds and iridium compounds can achieve a synergetic effect without adding alkali metal salt or alkaline earth metal salt to stabilize the rhodium catalyst, thereby greatly improving the catalytic activity, reducing the water content in the reaction, respectively controlling the pressure and temperature within an ideal range, decreasing the production of byproducts, and stabilizing and smoothing the reaction process.

Description

technical field [0001] The invention relates to a method for carbonylation of acetic acid, in particular to a method for carbonylation of rhodium and iridium to synthesize acetic acid. Background technique [0002] Among the existing acetic acid manufacturing patents, there are many patents on rhodium-based or iridium-based catalyzed carbonylation of acetic acid. The disadvantage of rhodium-based is that it is expensive, the catalyst itself is unstable and prone to precipitation, many by-products, and high water content requirements. After the improvement by adding alkali metal salt, the problem of precipitation and water content is solved, but the problem of excessive iodide ion content is caused, which causes the problem of equipment corrosion. Compared with rhodium-based catalysts, iridium-based catalysts are relatively stable, relatively cheap, require low water content, and have few by-products, but they need to maintain a high concentration of methyl acetate in the rea...

Claims

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Application Information

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IPC IPC(8): C07C53/08C07C51/12B01J31/30
Inventor 赵兵兵赖春波王群王培新
Owner SHANGHAI HUAYI ENERGY CHEM
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