Green Solid Acid Research Articles

Preparation of an improved sulfonated carbon-based solid acid as a novel, efficient, and reusable catalyst for chemoselective synthesis of 2-oxazolines and bis-oxazolines

A highly sulfonated carbon as an efficient, recyclable, nontoxic, and green solid acid catalyst was readily synthesized by simultaneous sulfonation, dehydration, and carbonization of sucrose in sulfuric acid and was characterized by FT-IR, TG-DTG, XRD, and CHNS analysis, neutralization potentiometric titration, and SEM techniques. This new catalyst was used for preparation of 2-oxazolines and bis-oxazolines by reaction of β-aminoethanol with nitriles under reflux conditions. Sonication of this system enhanced the catalytic activity of the carbon-based solid acid and led to higher product yields and shorter reaction times. Another advantage of the system under ultrasonic irradiation is the ability to carry out large-scale reactions. In two cases, the catalyst was reused several times without loss of its activity.

Catalytic Method for Synthesis of Aspirin by a Green, Efficient and Recyclable Solid Acid Catalyst (Preyssler's Anion) at Room Temperature

AbstractSynthesis of aspirin at room temperature via O‐acetylation of salicylic acid in the presence of Preyssler type heteropolyacids has been investigated in order to contribute toward clean technology, which is the most important need of the society. All of the catalysts are recyclable and reusable.

Effective direct esterification of butanol by eco-friendly Preyssler catalyst, [NaP 5W 30O 110] 14−

Direct esterification of butanol to butylbutanoate in the absence of butanoic acid has been investigated by a series of green solid acid catalysts, including H 14[NaP 5W 30O 110], H 14 -P 5 , H 14[NaP 5W 29MoO 110], H 14 -P 5 Mo and silica supported H 14[NaP 5W 30O 110], H 14 -P 5 /SiO 2 , with H 2O 2 as oxidizing agent at reflux and at room temperatures. The performance of these eco-friendly catalysts were compared with H 2SO 4. Maximum butylbutanoate yield and product selectivity (100%) was observed by using H 14 -P 5 Mo as the catalyst. The effects of various parameters such as catalyst type, reaction times, reaction temperatures, and molar ratio of n-butanol to hydrogen peroxide have been studied. The green catalysts can be easily recovered and recycled with retention of their initial structure and activity.

On the Peach, Polygonum japonicum and Cowpea Oils

The authors investigated the characteristics of three kinds of oils entitled above.A. Peach oilPeach fruit seed was extracted with ether to obtain sample of the oil, of which the characteristics of mixed acid, solid and liquid acids separated therefrom were as follows : Sample oil Mixed acid Solid acid Liquid acidYield, percent 16.47 94.0 40.41 59.59d154 0.9012 - - 0.9118n20D 1.4610 - - 1.4657A.V. 110.2 - - -S.V. 183.8 - - -N.V. - 201.4 202.8 200.2I.V. (Wijs) 105.5 104.0 74.2 123.1mp °C - 29.831.2 - -Unsaponifiable matter (%) 2.50 - - -Color Yellowish red Yellow Pale yellow Yellowish redSolid acid contained chiefly C18, C16 and little amount of C10, C12 acids (C18-F1-elaidic acid was also confirmed).Liquid acid contained chiefly C16, C18 and little amount of C12 acid.B. Polygonum japonicum oilPolygonum japonicum seed was extracted with ether to obtain sample of the oil, of which the characteristics of mixed acid, solid and liquid acids separated therefrom were as follows : Oil Mixed acid Solid acid Liquid acidYield, percent 2.70 87.80 17.42 82.58d154 0.9273 - - -n20D 1.4741 - - 1.4733A.V. 33.4 - -S.V. 184.4 N.V. 210.9 N.V. 211.7 N.V. 210.8I.V. 126.8 130.8 39.2 141.9Unsaponifiable matter (%) 5.85 - - -Color Dark yellow Yellowish brownPale yellow BrownThe solid acid contained chiefly C18, C16 and little amount of C14, C12 acids. The liquid acid contained chiefly C16, C18 and little amount of C12, C14 acids.C. Cowpea oilCowpea seed was extracted with ether to obtain sample of the oil, of which the characteristics of mixed acid, solid and liquid acids separated therefrom were as follows : Oil Mixed acid Solid acid Liquid acidYield, percent 0.56 81.53 63.87 36.14d154 0.9331 - - -n20D 1.4733 - - -A.V. 5.9 - - -S.V. 187.6 N.V. 205.5 N.V. 208.2 N.V. 199.5I.V. 129.7 126.1 76.3 179.8Unsaponifiable matter (%) 7.64 - - -Color Yellowish green Yellowish brown Pale yellow Dark redThe solid acid contained chiefly C16, C18 acids and little amount of C14. The solid acid which is insoluble in petroleum ether was found in the mixed fatty acids. The liquid acid contained chiefly C16, C18 and little amount of C12, C14 acids.The unsaponifiable matter had the following properties : Sample mp °C I.V. ColorA 121124 127.6 YellowB 113119 - Yellowish redC 135144 126.4 Yellowish white