Development of selective catalysts for hydroprocessing of phenol production by-products — hydroquinone and catechol

The development of a selective catalyst for hydroprocessing of phenol production by-products (hydroquinone and catechol) is an important task for increasing the yield of the target product. In this study, the use of in situ generated catalysts based on molybdenum and tungsten compounds (MoP, WP, MoO _x , and WO _x ) was proposed for this goal. The performance of the catalysts was investigated in the hydroprocessing of each individual substrate (hydroquinone and catechol), as well as their mixture. It was shown that MoP and WP catalysts were more selective in the partial HDO of hydroquinone and catechol into phenol compared to their oxides, as a result, the selectivity for phenol was higher. The hydroprocessing of a mixture of phenol, hydroquinone, and catechol (the molar ratio of phenol/hydroquinone/catechol = 7/2/1) was also explored using in situ formed MoP, WP, MoO _x , and WO _x catalysts. The phenol content in the product mixture after the reaction changed in the following order: WP (88%) > MoP (75%) > WO _x (55%) > > MoO _x (26%). Thus, in situ formed MoP and WP can be considered as the suitable catalysts for the selective HDO of hydroquinone and catechol towards phenol.