Preparation method of catalyst for synthesizing propionic acid by ethanol carbonylation, and application thereof

Abstract

The invention relates to a preparation method of a catalyst for synthesizing propionic acid by ethanol carbonylation, and an application of the catalyst. The catalyst is prepared by the following steps of: taking 2-vinyl pyridine and acraldehyde as monomers, benzene as a solvent and azodiisobutyronitrile as an initiator; adopting a free-radical solution polymerization method, and using petroleum ether for precipitation; carrying out vacuum drying to be at constant weight at the temperature of 60-80 DEG C to obtain a catalyst ligand; dissolving the obtained catalyst ligand in acetic acid, adding dichloro-tetracarbonyl-dirhodium, and carrying out reaction for 10-30min; and adding a precipitator (sodium tetraphenylborate), and continuously stirring for 5-20min to obtain a copolymer rhodium catalyst. The catalyst can be used for catalyzing ethanol carbonylation to synthesize the propionic acid with high selectivity.

Description

technical field [0001] The invention belongs to the field of preparing propionic acid by carbonylation reaction of ethanol, and in particular relates to a catalyst and a preparation method thereof. Background technique [0002] Propionic acid is an important basic chemical raw material. Propionic acid and its ester derivatives are widely used in industrial organic synthesis, food and feed preservation, pesticides, spices, cosmetics and medicine. [0003] The main processes for industrial production of propionic acid include Repa method, propionaldehyde oxidation method and light hydrocarbon oxidation method. While these methods are successfully applied to industrial production, they also show obvious shortcomings, such as high temperature requirements (250-320°C); high pressure (10-30MPa) requirements; cumbersome process flow; complex reaction liquid composition, requiring special purification devices Wait. In order to solve the shortcomings of the current industrial p...

AI Technical Summary

Problems solved by technology

Although theoretically speaking, the gas phase reaction device is simple, convenient for product separation, and less corrosive to equipment, but for the reaction of ethanol carbonylation of propionic acid, there are considerable limitations: (1) The loss of active species of the catalyst , the carbon on the surface of this type of strong exothermic reaction catalyst, etc., all directly affect the life and performance of the catalyst; (2) the dew point of the product propionic acid in the reaction system, according to literature reports, the reaction pressure and temperature can meet the requirements of ethanol and Ethyl iodide exists and reacts in a gaseous state during the reaction, but the product propionic acid is not in a gaseous state, that is, the generated propionic acid flows out of the fixed-bed reactor in liquid form, which will inevitably cause erosion and dissolution loss of the surface active species of the catalyst

[0004] In short, the low-pressure gas-phase methanol carbonylation of acetic acid has not formed an industrial production process after decades of research and development, and the research on the more complicated gas-phase reaction process of ethanol carbonylation to propionic acid obviously still has a longer way to go