Oxo synthesis catalyst and its prepn process and application in preparing acetic acid and acetic anhydride

Abstract

The present invention relates to positive and negative ion type bimetal catalyst with pyridine carboxylic acid as ligand and used for oxo synthesis of acetic acid and acetic anhydride. Of the catalyst, the active positive ion center is square planar cis-bicarbonyl structure formed with pyridine carboxylic acid and Rh(I); and the negative ion active component is coordination compound structure formed with pyridine carboxylic acid and RE metal La, Ce or Nd. Owing to synergetic effect of the special coordination compound structure and metals, the catalyst exhibits excellent activity in catalyzing methanol carbonylation to synthesize acetic acid and catalyzing methyl acetate carbonylation to synthesize acetic anhydride. The space time yield of acetic acid may reach 40 mol / L.hr, and that of acetic anhydride may reach 10 mol / L.hr.

Description

technical field [0001] The invention belongs to carbonylation catalysts, in particular to carbonylation catalysts for acetic acid and acetic anhydride. Background technique [0002] Methyl alcohol and carbon monoxide carbonylation reaction prepare acetic acid, methyl acetate and carbon monoxide carbonylation reaction prepare acetic anhydride, since the homogeneous rhodium catalyst technical route that Paulik et al. , the reaction rate is high, and it has become the most important production process route in the acetic acid and acetic anhydride industries. [0003] For quite a long period of time, the rhodium catalysts used in industrial production mostly use rhodium salts or monometallic complexes of rhodium, and the active species of the catalyst is dicarbonyl diiodo rhodium Rh (I) anion complex (Haynes A , et al, J. Am. Chem. Soc., 1991). This type of catalyst active center has high catalytic activity and selectivity. However, in the reaction process, especially in the ...

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Problems solved by technology

However, in the reaction process, especially in the catalyst separation part, sometimes it is easy to generate trivalent rhodium precipitation, such as [Rh(CO) 2 I 2 ] - N + R 4 Convert to [Rh(CO) 2 I 4 ] - N + R 4 , and inactive

In addition, due to the low solubility of the catalyst in the reaction medium, the concentration of the catalyst is usually relatively low, which limits its production efficiency

In order to overcome this deficiency, it is necessary to maintain a certain amount of water and hydroiodic acid in the reaction system during the industrial production of acetic acid, which not only increases the corrosiveness of the reaction medium, but also consumes the raw material carbon monoxide due to the water gas reaction between water and carbon monoxide.

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