Catalytic system used for homogeneous hydroxylation reaction and its manufacturing method and application

Abstract

A homologeous catalyst system for the hydroxylation reaction of methanol to obtain acetic acid or the carbonylating reaction of methyl acetate to obtain ethylanhydride is composed of the primary catalyst (rhodium acetate (or nitrate) as coordination center and potassium), cocatalyst (iodomethane), additive (lithium iodide, potassium iodide, or lithium acetate), and polar solvent (acetic acid, ethylanhydride, methyl acetate, or water). Its preparing process includes dissolving picolinic acid and hydrated potassium in methanol or water to obtain organic potassium ligand, dissolving in water or methanol solution, and dripping rhodium solution.

Description

technical field [0001] The present invention relates to a catalytic system for homogeneous hydroxylation reactions. [0002] The present invention also relates to the preparation method of the main catalyst in the above catalytic system. [0003] The present invention also relates to the application of the above-mentioned catalytic system in the carbonylation reaction of methanol and the carbonylation reaction of methyl acetate. Background technique [0004] Since the 1970s, the Monsanto Company of the United States successfully invented the low-pressure methanol carbonylation acetic acid process, which gradually replaced the two-step process such as the ethylene process, and the acetic acid industry has developed rapidly. The active center of the catalyst used in this method is diiodide rhodium dicarbonyl, such as [Rh(CO) 2 I 2 ] - N + R 4 , [Roth, J.F.et al.Chem.Technol., 1971,600], this type of complex is very unstable in the reaction process, and it is very easy to...

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Problems solved by technology

[0005] In order to improve this situation, many researchers have proposed to change the homogeneous method into a heterogeneous method, that is, the rhodium series catalysts that have been studied a lot in recent years with polymers as ligands, such as 4-vinylpyridine and styrene. The polymer obtained from the monomer is the rhodium complex catalyst of the ligand, and its stability is better [EP567331,27 Oct 1993], but the solubility of this type of catalyst is not good, so that the activity of the reaction is not ideal

[0006] Some research reports have proposed the use of a gas-solid phase method, that is, the active center of the catalyst is supported on a solid carrier, and the mixture of methanol, methyl iodide and carbon monoxide is passed through the fixed-bed catalyst at a certain temperature and pressure, but this process consumes a lot of The cocatalyst iodide methyl, in the reaction process, due to the high temperature, easy carbon deposition, causing problems such as catalyst deactivation, rhodium loss, etc., it is still impossible to realize industrialization

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