Alkylation of Hydroquinone with tert-Butanol Catalyzed by Polymer-supported Sulfonimide

Abstract

Polystyrene with pendant perfluorobutylsulfonylimide (PPFSI) was developed as a novel polymersupported strong acid catalyst for alkylation of hydroquinone (HQ) with tert-butanol (TBA), and highly selective synthesis of 2-tert-butyl hydroquinone (2-TBHQ) was investigated over PPFSI under various experiment conditions. When the molar ratio of TBA to HQ was 1.2:1, using 3 mol% of PPFSI as catalyst in 1,2-dichloroethane at 130°C for 5 h, the maximum of selectivity (85.9%) of 2-TBHQ was obtained while the conversion of HQ was 76.7%. Compared with other solid acid catalysts PPFSI was found to be a very effective and reusable catalyst for alkylation of hydroquinone with tert-butanol.

ESTERIFICATION OF SALICYLIC ACID USING Ce4+ MODIFIED CATION-EXCHANGE RESIN AS CATALYST

“…By further heating (from 310 up to 510ºC), a two step endothermic process happened. The weight loss between 310 and 420ºC may be attributed to the loss of the sulfonic groups and short alkyl groups in resin 28 . The weight from 420 to 510ºC was lost in the transformation of Ce(SO 4 ) 2 into Ce 3 O 2 (SO 4 ) 4 and SO 3 .…”

Use of an efficient polystyrene‐supported cerium catalyst for one‐pot multicomponent synthesis of spiro‐piperidine derivatives and click reactions in green solvent

“…The use of a core metal salt as a catalyst is associated with a major problem of recovery of the catalyst from the reaction medium making reaction work‐up and product isolation tedious. To overcome this problem, researchers have made great efforts to find eco‐friendly reusable heterogeneous catalysts based on organic, inorganic and organic–inorganic hybrid solid supports for various organic transformations . Polystyrene is one of the most widely studied heterogeneous and polymeric supports due to its low cost, ready availability, environmental stability and hydrophobic nature which protects water‐sensitive Lewis acids from hydrolysis by atmospheric moisture until suspended in an appropriate solvent where they can be used in a chemical reaction .…”

Long-chain double SO3H-functionalized Brønsted acidic ionic liquids catalyzed selective alkylation of phenol andp-cresol with tert-butanol

“…Homogenous and heterogeneous catalysts were developed for this transformation. For example, AlCl 3 , FeCl 3 , and ZnCl 2 (4), H 2 SO 4 , H 3 PO 4 , HF, HClO 4 (5), mesoporous materials (6)(7)(8), heteropoly acids (9), zeolites (10), cation exchange resin (11), sulfated zirconia (12), polymer-supported sulfonamide (13), silica supported Al (14), and transition metal oxides (15), and so on. However, based on the standards of green chemistry, these procedures are suffering from disadvantages, such as corrosion equipments, lack of selectivity, environmental pollution, complex processes and difficult work-ups, catalyst with high cost or poor thermal stability, prone to deactivation, etc.…”