Preparation method of (1,5-cyclooctadiene) rhodium chloride (I) dimers

Abstract

The invention provides a preparation method of (1,5-cyclooctadiene) rhodium chloride (I) dimmers. The method comprises the following concrete steps of (a) dissolving rhodium chloride hydrate by deionized water so that the rhodium concentration in the rhodium chloride water solution is 3 to 8 percent; putting the materials into a reaction kettle; connecting the upper end of the reaction kettle with a condensing pipe; adding absolute ethyl alcohol into the reaction kettle; performing heating, stirring and temperature rise; when the temperature rises to 35 DEG C, dripping a mixed solution of 1,5-cyclooctadiene COD and absolute ethyl alcohol; after the solution dripping is completed, adding a phase transfer catalyst PEG-400; performing reaction for 4 to 7 hours at 35 to 80 DEG C to obtain orange precipitates and suspension; performing filtering; (b) cooling the suspension in the step (a) to the room temperature; performing vacuum suction filtration to obtain a solid-state product; (c) washing and drying the solid-state product in the step (b). The product yield is 80 to 85 percent. By using the method, during the synthesis, the phase transfer catalyst PEG-400 is added, so that the raw materials and the ligand can be changed from two phases into one phase under the temperature reduction condition; the reaction temperature is reduced; the reaction temperature is reduced from 60 to 85 DEG C to 30 to 40 DEG C, but the reaction time cannot be prolonged.

Description

Technical field [0001] The present invention relates to the technical field of preparation methods of platinum group metal compounds with 1,5-cyclooctadiene as a ligand, in particular to a (1,5-cyclooctadiene) rhodium chloride (I) dimer Preparation. Background technique [0002] (1,5-Cyclooctadiene) rhodium(I) chloride dimer is a commonly used chiral catalyst, mainly used for coupling reactions, asymmetric hydrogenation reactions and hydroboration reactions. The reported synthetic process routes are similar. The only difference is the choice of solvent and temperature. Jinpeng et al. used RhCl 3 ·3H 2 O is the raw material, dissolved in a degassed ethanol-water mixed solvent under the protection of nitrogen, and reacted with degassed COD (1,5-cyclooctadiene) at 85°C. After the reaction, the precipitate is filtered and the organic solvent is washed with ethanol. The target product can be obtained from impurities. This method requires 4-5 hours at 85°C. The product after washing w...

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Problems solved by technology

The reported synthetic process routes are similar, the difference is only in the choice of solvent and the temperature, Jinpeng et al. 3 ·3H 2 O is the raw material, dissolved in degassed ethanol water mixed solvent under the protection of nitrogen, reacted with degassed COD (1,5-cyclooctadiene) at 85°C, filtered the precipitate after the reaction, washed the organic with ethanol Impurities can be used to obtain the target product. This method requires 4-5 hours at 85°C. The product after washing with ethanol is easily oxidized and cannot be placed in the air for a long time.

Cang Yu etc. also adopt this method to carry out the synthesis of (1,5-cyclooctadiene) rhodium (I) chloride dimer, but the reaction temperature will be 60 ℃, although the reaction temperature is reduced to some extent, the reaction time needs Corresponding extension

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