A catalyst and a preparation method thereof, the catalyst providing a high production yield of C8 aromatic hydrocarbons in the conversion of a feedstock containing alkyl aromatics to C8 aromatic hydrocarbons such as mixed xylene through at least one of disproportionation, transalkylation, and dealkylation while reducing a content of ethylbenzene in the product.

The processes upgrade a low value heavy aromatics stream into a high value BTX precursor stream. It treats the naphthalenic molecules in the heavy aromatics stream comprising C.sub.9 to C.sub.12 aromatics prior to reaching the transalkylation reactor. The naphthalenic molecules are converted into BTX precursors by partially hydrogenating one of the aromatic rings and subsequently ring opening the saturated ring to form a monoaromatic prior to the transalkylation reactor. With naphthalene no longer present, the remaining C.sub.11 monoaromatics may be processed in the aromatics complex for an overall increased BTX production.

Bisphosphites with a 3,4-dialkylphenol outer unit

Bisphosphites with a monoalkylphenol outer unit and the use thereof in hydroformylation.

Bisphosphites with a 2-phenylphenol outer unit and the use thereof in hydroformylation.

Bisphosphites with a naphthol outer unit and the use thereof in hydroformylation.