Catalyst system for methanol low-pressure carbonyl synthesis of acetic acid and application thereof

Abstract

The invention relates to a catalyst system used for methanol low-pressure carbonyl synthesis of acetic acid, which uses rhodium compounds as the active component carbonylation of carbonyl synthesis catalyst and uses alkyl iodide, water, hydroiodic acid, alkali metal iodate and sulfonate as promoters, and uses acetic acid as polar solvent. Because sulfonate is added to the catalyst system, better catalytic activity and stability are achieved. In methanol carbonylation, the catalyst system can convert methanol into acetic acid at high speed with high selectivity under lower temperature and pressure. The reaction reduces the concentration of water and hydroiodic acid, and reduces corrosivity to equipment.

Description

technical field [0001] The invention relates to a catalyst system for catalyzing the low-pressure carbonylation of methanol to acetic acid and its application. Background technique [0002] The industrial production methods of acetic acid include acetaldehyde oxidation, butane or light oil liquid phase oxidation, and methanol carbonylation. Among them, the methanol low-pressure carbonylation method has the advantages of simple process, mild reaction conditions, good selectivity, and low energy consumption. It has become the most competitive production method of acetic acid in the world, and it is also the main production route for the synthesis of acetic acid in the world. In addition, the raw material methanol has sufficient supply and low cost, and has the characteristics of atomic economic reaction in which all reactant molecules generate all target product molecules. While reducing the environmental pollution caused by by-products, it is of great significance to the coor...

AI Technical Summary

Problems solved by technology

[0008] Although the catalyst structure model in the current industrial production has good catalytic activity, it is easy to convert into a trivalent rhodium anion complex at high temperature and low carbon monoxide partial pressure, and then precipitates and loses its activity.

In addition, in order to increase the solubility of the catalyst in the acetic acid production process, the reaction system needs to maintain higher water and hydroiodic acid content so as to maintain the higher reactivity of the system (EP55618, EP161874), but therefore accelerates the water gas reaction and consumes The raw material is carbon monoxide, and the strong corrosiveness of the medium increases the requirements for equipment materials, and the large amount of water in the system increases the complexity of the product post-treatment process