Method for determining active rhodium content of acetic anhydride carbonyl synthesis reaction liquid prepared from methyl acetates

Abstract

The invention discloses a method for determining the active rhodium content of acetic anhydride carbonyl synthesis reaction liquid prepared from methyl acetates. The method comprises the following steps: preparing a rhodium-series standard solution and a sample solution by using a mixed solvent prepared by mixing DMF (dimethyl formamide) with water, wherein the volume ratio of the DMF to the water is 8:2 or 9:1; then, respectively determining the intensities of spectral lines of rhodium by using an inductance coupling plasma emission spectroscopy(ICP-AES); and finally, calculating the rhodiumcontent according to a rhodium standard curve. By using the method provided by the invention, the active rhodium content of the carbonyl synthesis reaction liquid can be accurately determined; meanwhile, the method is good in selectivity, high in sensitivity, wide in linear range, small in impurity disturbance, high in accuracy, and simple in operation, therefore, the method is applicable for determining the active rhodium content of complex organic synthesis reaction liquid.

Description

1. Technical field [0001] The invention relates to an analysis method of inorganic elements, in particular to an instrument analysis method, specifically a method for determining the content of active rhodium in a reaction liquid of oxo-synthesis of acetic anhydride from methyl acetate. 2. Background technology [0002] Methyl acetate carbonylation acetic anhydride process is to take methyl acetate and carbon monoxide as raw materials, with rhodium triiodide (or rhodium trichloride) as the main catalyst, methyl iodide as a catalytic accelerator, and lithium acetate as a catalytic co-accelerator, Oxo-synthesis reaction is carried out under 175°C and 3.6MPa high pressure, the reaction mechanism is extremely complex, and there are many by-products. In addition to low-boiling point by-products such as acetaldehyde, acetone, and propionic acid, there are also high-boiling point products such as ethyl diacetate. Forked esters, tar, etc. are generated. Rhodium triiodide or rhodium...

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Problems solved by technology

If the above sample treatment method is used, the tar will be carbonized into fine carbon powder, and the carbonyl rhodium in the reaction solution will also be carbonized, and part of the rhodium will be trapped in the carbon powder and cannot be dissolved out, and the fine carbon powder will block the flame when the sample is injected. The nozzle of the atomic absorption spectrometer or plasma emission spectrometer pollutes the nebulizer, causing large fluctuations in the measurement results, and the measurement results are low

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