Process for production of acetic acid

一种乙酸、元素周期表的技术，应用在有机化学方法、一氧化碳反应制备羧酸、有机化学等方向，达到实现乙酸生产率、醋酸产率提高、提高催化剂活性的效果

Inactive Publication Date: 2011-08-24
DAICEL CORP
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, introducing hydrogen into the reactor to keep the partial pressure of hydrogen high will lose the effect of reducing by-products, one of the advantages obtained by reducing the concentration of water in the reaction liquid.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0034] will contain the rhodium complex ([Rh(CO) 2 I 4 ] - ) of the catalyst composition liquid (rhodium catalyst concentration: in rhodium, 700 wtppm, solvent: 86 wt% of acetic acid, 2 wt% of water, 12 wt% of lithium iodide) was continuously introduced into a 28.8ml container with a heating jacket Among them, the rhodium complexes are all complexes of trivalent rhodium, and the ratio of hydrogen to carbon monoxide is 1:3 to supply the mixed gas with the ratio of hydrogen to carbon monoxide in an amount of 2.3 mol times that of rhodium, and the catalyst composition liquid and the Said mixed gas was contacted for 53 seconds at the temperature recorded in Table 1 at a pressure of 2.8 MPaG. Table 1 shows the ratio (%) of monovalent rhodium produced as measured by infrared absorption spectroscopy.

[0035] Table 1

[0036] Contact temperature (°C)

Embodiment 2

[0038] The catalyst composition liquid (rhodium catalyst concentration: calculated as rhodium, 700 wt. ppm, solvent: 86 wt. % of acetic acid, 2 wt. % of water, 12 wt. % of lithium iodide) comprising a rhodium complex is continuously introduced into a heating jacket In a container of 28.8ml, the rhodium complexes are all complexes of trivalent rhodium, and the ratio of hydrogen to carbon monoxide is 1:3 to supply the mixed gas of hydrogen and carbon monoxide in an amount of 1.1 mol times relative to rhodium, and the catalyst The composition liquid was contacted with the mixed gas at a pressure of 2.8 MPaG and a temperature of 125° C. for 53 seconds. The ratio (%) of monovalent rhodium formation measured by infrared absorption spectroscopy was 72%.

Embodiment 3

[0040] In a reactor with an inner volume of 1L, the reaction raw materials methanol (0.21kg / h) and carbon monoxide, the catalyst solution containing rhodium catalyst and lithium iodide, and the catalyst solution containing methyl iodide (0.28kg / h), methyl acetate (0.095kg / h), low-boiling components of water (0.008kg / h); react at reaction pressure 3.0MPa, hydrogen partial pressure 29kPa, reaction temperature 196 ℃; Concentration: 0.45% by weight, methyl acetate concentration: 4.7% by weight, methyl iodide concentration: 14.5% by weight, rhodium catalyst concentration: 930 wtppm in terms of rhodium, lithium iodide concentration: 11.7% by weight), evaporated low boiling point components and the generated acetic acid; the unevaporated catalyst solution (rhodium catalyst concentration: 1480 wtppm calculated as rhodium) was pressurized with a pump, and circulated to the reactor at a flow rate of 1.30kg / h. Wherein, in this step, before the catalyst liquid enters the reactor, the mix...

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PUM

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Abstract

Disclosed is a process for producing acetic acid by reacting methanol with carbon monooxide continuously in the presence of a catalyst of a metal belonging to Group VIII on the periodic table, a salt of an iodide, methyl iodide and water. In the process, the reaction solution is removed continuously and subjected to a distillation step wherein the pressure is lower than that included in the reaction conditions to be separated into a low-boiling component fraction and a high-boiling component fraction containing the metal belonging to Group VIII on the periodic table and the salt of the iodide, and hydrogen is introduced into an region required for returning the separated high-boiling component fraction to the reactor in an amount of 0.1 times by mole larger than that of the metal belonging to Group VIII on the periodic table and is allowed to contact with the high-boiling component fraction at 80 DEG C or higher for at least 6 seconds before the high-boiling fraction returns to the reactor. The process can increase the activity of the catalyst in the reactor without the need of increasing the partial pressure of hydrogen in the reactor to an excess degree, can inhibit a shift reaction to reduce the production of any by-product, and can produce acetic acid in an industrial scale with good efficiency and high productivity rate.

Description

technical field [0001] This invention relates to a process for the preparation of acetic acid from methanol and carbon monoxide. Background technique [0002] Acetic acid is one of the basic chemicals, and it is an important chemical in petrochemical industry, polymer chemical industry, organic chemical industry, pharmaceutical and pesticide manufacturing industry. There are various methods for producing acetic acid, and among these methods, the method for producing acetic acid from methanol and carbon monoxide is the most industrially excellent method. [0003] As an improvement method of this method, a method of reducing the water concentration in the reaction solution has been proposed (JP-A-4-69136 and JP-A-7-23337). That is, it discloses a technology capable of increasing the productivity of acetic acid and reducing the yield of by-products by reducing the water concentration in the reaction solution. In these technologies, it is also disclosed that if the concentrati...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07C51/12C07C53/08C07B61/00
CPCC07C51/12C07C53/08C07B61/00
Inventor 小岛秀隆
Owner DAICEL CORP
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