AN EFFICIENT AND CHEMOSELECTIVE SYNTHESIS OF ALDEHYDE 1,1-DIACETATES USING MORPHOLINIUM BISULFATE AS A BRÖNSTED ACIDIC IONIC LIQUID UNDER SOLVENT-FREE CONDITIONS

Novel Carbon-based Solid Acid from Green Pistachio Peel as an Efficient Catalyst for the Chemoselective Acylation, Acetalization and Thioacetalization of Aldehydes, Synthesis of Biscoumarins and Antimicrobial Evaluation

Background:

Much attention has been focused on heterogeneous catalysts. Reactions with these recoverable and reusable catalysts are clean, selective with high efficiency. Among the heterogeneous solid acid catalyst in organic synthesis, Carbon-Based Solid Acids (CBSAs), which are important solid acid with many practical and research applications have been extensively studied. In this work, green Pistachio peel, a biomass waste, was converted into a novel carbon-based solid acid catalyst (Pis-SO3H).

Objective:

The aim of this work is to synthesize highly sulfonated carbon as an efficient, recyclable, nontoxic solid acid catalyst by simultaneous sulfonation, dehydration and carbonization of green Pistachio peel as biomass and investigate the catalytic activity of Pis-SO3H in acetalization, thioacetalization, acylation of aldehydes and synthesis of 3,3'-Arylmethylene-bis(4-hydroxycoumarin) derivatives.

Method:

Pis-SO3H was synthesized by an integrated fast one-step hydrothermal carbonization and sulfonation process in the presence of sulfuric acid. The characterization of the physicochemical properties of Pis-SO3H was achieved by XRD, FT-IR, FE-SEM, and elemental analysis.

Results:

The result of acid-base titration showed that the total acidity of the catalyst was 7.75 mmol H+g−1. This new heterogeneous catalyst has been efficiently used for the chemoselective thioacetalization, acetalization and acylation of aldehyde and the synthesis of biscoumarins under solvent-free conditions. All the reactions work easily in high yields. The antimicrobial activity of some of the biscoumarins was evaluated in screening by disk diffusion assay for the zone of inhibition.

Conclusion:

The catalytic activity of the Pis-SO3H was investigated during acetalization, thioacetalization, acylation and synthesis of biscoumarins. The results of protection of carbonyl groups and synthesis of biscoumarins in the present work offer effective alternatives for environmentally friendly utilization of abundant biomass waste.

Brønsted acidic ionic liquids: Innovative starch desizing agents

The possibility of using a synthesized inexpensive Brønsted acidic ionic liquids for starch desizing of a textile substrate for the first time was investigated under different conditions in terms of temperature, concentration and treatment time. The samples evaluation was carried out by Fourier transform infrared spectroscopy, microscopic studies, Tegewa tests, measuring weight loss, tensile strength, wetting properties and changes in the samples shades. The results indicated that the ionic liquids have strong effect on the cotton fabric starch desizing (Tegewa 6 or higher) with no adverse effect on the samples strength and whiteness. Thus, it was revealed that proper ionic liquids could be counted as novel starch desizing agents and alternative for the enzymatic process. In addition, it was observed that the acidic ionic liquids because of their specific structure do not have negative aspects of common acidic processes with no sensitivities and drawbacks of enzymatic treatments.