Preparation and application of p-xylyl ether_Kain Industrial Additive

Background and overview^[1]

P-xylyl ether is an organic intermediate that can be prepared from p-cresol and p-methylchlorobenzene in one step. There are reports in the literature that p-xylyl ether can be oxidized to prepare 4,4′-diphenyl ether dicarboxylic acid.

Preparation^[1]

Add p-cresol (1.2mmol), copper iodide (0.05mmol), ligand L-II-34 (0.1mmol), and potassium phosphate (2.0mmol) into a 10mL sealed tube, and evacuate to replace the argon gas. 3 times, then add p-methylchlorobenzene (1.0mmol) and 1mL DMSO, and stir the reaction evenly at 120°C for 24 hours. After cooling, wash the contents of the sealed tube with ethyl acetate, and filter it with silica gel and diatomaceous earth cartridges. , the filtrate was concentrated and then subjected to column chromatography to obtain the product p-xylyl ether.

Apply^[2]

CN201810191980.6 discloses a method for preparing 4,4′-diphenyl ether dicarboxylic acid by catalytic oxidation of metal oxides. 4,4′-Diphenyletherdicarboxylic acid, (4,4′-Oxybisbenzoic acid), has a light brown powdery crystal appearance, a melting point of 329°C, and a content of ≥98%. It is a monomer used in liquid crystal polymers. Used in electronics and pharmaceutical industries. The preparation method includes the following steps: p-xylyl ether undergoes an oxidation reaction in a solvent under the action of an oxidant, an organic metal catalyst, a ligand and an additive. The oxidation reaction temperature is 85-145°C, and the gauge pressure of the reaction is 1.0-5.0 MPa, the reaction time is 5-24h; after the reaction is completed, 4,4′-diphenyl ether dicarboxylic acid is obtained through post-treatment; wherein: the organic metal catalyst is selected from cobalt acetate, manganese acetate, cerium acetate, cobalt nitrate, nitric acid One or two of manganese, cobalt acetylacetonate, iron acetylacetonate or cerium ammonium nitrate, and the additive is an alkaline substance. The invention uses metal oxide as the catalyst and hydrogen peroxide, air or oxygen as the oxidant, thereby reducing the manufacturing cost and the generation of three wastes, easing the pressure on environmental protection, and also has the characteristics of easy control and industrial production.

References

[1] [Chinese invention] CN201610237829.2 Oxalamide ligands and their use in copper-catalyzed aryl halide coupling reactions

[2] [Chinese invention] CN201810191980.6 A method for preparing 4,4`-diphenyl ether dicarboxylic acid by catalytic oxidation of metal oxides