Sulfonated Polyimide Membranes Derived from a Novel Sulfonated Diamine with Pendant Benzenesulfonic Acid for Fuel Cells

For improving the hydrolytic stability of sulfonated polyimides consisting of five membered anhydrides, novel sulfonated polyimides (NSPIs) were prepared via polymerization of 3,3′,4,4′-benzophenonetetracarboxylic dianhydride (BTDA), with a novel diamine monomer with a pendant sulfonic acid group and 4,4-oxydianiline. Water uptake of this NSPI with an excellent film-forming ability was almost equal to that of Nafion® 117, while their ion exchange capacity (IEC) was 22% higher than Nafion® 117. The loss in weight decreased by 53% and loss in IEC decreased by 66% compared to that of Nafion® 117; both were used to quantitatively measure hydrolytic stability, and radical oxidative stability also increased by 75% when compared with Nafion® 117. Mechanically, this NSPI was superior, and its proton conductivity was higher than Nafion® 117 at elevated temperatures. All these improvements were due to the introduction of this pendant group. Taken together, we herein report a promising renewable energy source based on SPIs capable of displaying proton conductivity and enhanced hydrophilicity.

Benzenesulfonic Acid - an Green Efficient Esterification Catalysts for Continuous Synthesis of n-propyl Acetate

The esterification of acetic acid and n-propanol catalyzed by benzenesulfonic acid and its derivatives in the batch and continuous rectification tower was studied, in order to develop a new effective and green catalyst instead of the oxidative and corrosive sulfuric acid. A series of the comparison system with sulfuric acid was build for the targeted and fast evaluation of catalysts. The results showed that the catalytic esterification activity of p-phenolsulfonic acid and p-toluenesulfuric acid is very closed to sulfonic acid in the continuous rectification tower. Furthermore, the stability test for continuous esterification with p-toluenesulfuric acid presented that the high yield of n-propyl acetate could maintain 50 hours and stability. Therefore, p-phenolsulfonic acid and p-toluenesulfuric acid could be prospective substitutes for sulfuric acid for the continuous synthesis of n-propyl acetate in the rectification tower.

Surfactant-mediated thioglycosylation of 1-hydroxy sugars in water

Dodecyl benzenesulfonic acid (DBSA)-mediated thioglycosylation in water provided thioglycosides without open-chain dithioacetal sugars, which are common by-products when performing reactions in organic solvent.