Synthesis of sulfonic acid functionalized carbon catalyst from glycerol pitch and its application for tetrahydropyranyl protection/deprotection of alcohols and phenols

Highly efficient protection of alcohols and phenols catalysed by tin porphyrin supported on MIL‐101

“…For this purpose, various catalysts such as K‐10 montmorillonite, zirconium sulfophenylphosphonate, iodine, H 3 PW 12 O 40 , sulfonic acid‐functionalized ordered nanoporous Na + –montmorillonite, sulfonic acid‐functionalized nanoporous silica, ZrO(OTf) 2 , Bi(OTf) 3 , [Sn IV (TPP)(BF 4 ) 2 ], nanocrystalline TiO 2 –HClO 4 , [Ti IV (salophen)(OTf) 2 ], InBr 3 , 1,3‐disulfonic acid imidazolium hydrogen sulfate, Ru III (OTf)salophenCH 2 –NHSiO 2 –Fe, alumina‐supported heteropolyoxometalates, ZrCl 4 and H 14 [NaP 5 W 29 MoO 110 ] have been introduced for the silylation of alcohols and phenols with 1,1,1,3,3,3‐hexamethyldisilazane (HMDS) as a stable, cheap and commercially available reagent. Also, various catalysts like polystyrene‐supported GaCl 3 , N , N ′‐dibromo‐ N , N ′‐1,2‐ethanediylbis(benzene sulfonamide), La(NO 3 ) 3 ⋅6H 2 O, ferric perchlorate, vanadyl(IV) acetate, activated carbon‐supported sulfuric acid, {[K.18‐crown‐6]Br 3 } n , tungstosilicate salts, silica–alumina‐supported heteropoly acids, sulfonic acid‐functionalized carbon catalyst from glycerol pitch, aniline–terephthalaldehyde resin p ‐toluenesulfonic acid salt, Al(OTf) 3 , p ‐toluenesulfonic acid, Ru(CH 3 ) 3 (triphos)](OTf) 2 and K 5 CoW 12 O 40 ⋅3H 2 O have been developed for the tetrahydropyranylation of alcohols and phenols. Because of the importance of these reactions, development of efficient and versatile catalytic systems for the protection of alcohols and phenols is still expedient.…”

Glycerol-Based Carbon-SO<sub>3</sub>H Catalyzed Benign Synthetic Protocol for the Acetylation of Alcohols, Phenols and Amines under Solvent-Free Conditions

“…Carbon-based solid acid catalysts [45][46][47][48] have gained importance due to their significant advantages over homogeneous liquid phase mineral acids, such as increased activity and selectivity, longer catalyst life, negligible equipment corrosion, ease of product separation, and reusability. We, recently developed a simple and fast method for the preparation of a similar sulphonic acid functionalized polycyclic aromatic carbon catalyst from bioglycerol (biodiesel by-product) and also from glycerol-pitch (waste from fat splitting industry) by in situ partial carbonization and sulfonation [49,50]. Such catalysts have been shown to be inexpensive, highly stable, robust, recyclable, and easily produced from naturally available bioglycerol, and are demonstrated to be effective for the esterification of fatty acids to its methyl esters [49], THP protection and deprotection of alcohols and phenols [50], and also for the synthesis of highly substituted imidazoles [51], 3,4-dihydropyrimidin-2-(1H)ones [52], amides from aldehydes [53], and spirooxindole derivatives [54].…”

“…We, recently developed a simple and fast method for the preparation of a similar sulphonic acid functionalized polycyclic aromatic carbon catalyst from bioglycerol (biodiesel by-product) and also from glycerol-pitch (waste from fat splitting industry) by in situ partial carbonization and sulfonation [49,50]. Such catalysts have been shown to be inexpensive, highly stable, robust, recyclable, and easily produced from naturally available bioglycerol, and are demonstrated to be effective for the esterification of fatty acids to its methyl esters [49], THP protection and deprotection of alcohols and phenols [50], and also for the synthesis of highly substituted imidazoles [51], 3,4-dihydropyrimidin-2-(1H)ones [52], amides from aldehydes [53], and spirooxindole derivatives [54]. In continuation of our efforts towards exploring the applications of the glycerol-based carbon catalyst, here we report a simple and an efficient methodology for the acetylation of alcohols, phenols and amines with acetic anhydride at 65  C under solvent-free conditions in excellent yields (Scheme 1).…”

Bioglycerol-based Sulphonic Acid Functionalized Carbon: An Efficient and Recyclable, Solid Acid Catalyst for the Regioselective Azidolysis of Epoxides in Aqueous Acetonitrile

“…These carbon-based catalysts, obtained by the incomplete carbonization and sulphonation of aromatic hydrocarbons or sugars, consisting of small polycyclic aromatic carbon sheets with attached -SO 3 H groups, have proven to be highly active in the esterification of fatty acids. Prabhavathi et al reported a sustainable method for the preparation of similar sulphonic acid functionalized polycyclic aromatic carbon catalyst from bioglycerol biodiesel by-product and also from glycerol-pitch waste from fat splitting industry by in situ partial carbonization and sulphonation 41,42 .…”

“…Such catalysts have been shown to be inexpensive, highly stable, robust, recyclable, and easily produced from naturally available glycerol, and are demonstrated to be effective for the esterification of fatty acids to its methyl esters 41 , THP protection and deprotection of alcohols and phenols 42 , one-pot synthesis of highly substituted imidazoles 43 , 3,4-dihydropyrimidin-2-1H -ones 44 and a mild and expeditious synthesis of amides from aldehydes 45 . In continuation of our efforts towards exploring the applications of the carbon-based catalysts, we are reporting a simple and highly efficient approach for the regioselective azidolysis of epoxides to azido alcohols under mild reaction conditions using glycerol-based sulphonic acid functionalized carbon as a recyclable catalyst.…”