Sulfated Polyborate Research Articles

Improvement in BHETA yield by aminolysis and its application in hot melt adhesive

Polyethylene terephthalate (PET) recycling has been carried out by various methods, e.g., mechanical recycling, chemical recycling, and energy recovery method. In this study, chemical recycling of PET was carried out by aminolysis using ethanolamine and converted into bis(2-hydroxyethyl) terephthalamide (BHETA). We have studied the effective polymeric catalysis of the aminolytic depolymerization of waste polyethylene terephthalate (PET) using sulfated polyborate producing a broad range of crystalline terephthalamides. The reaction was performed by varying the PET: ethanolamine ratio, reaction time and catalyst. Recycled PET bottles, film, and fibres were used for conversion. A yield of 95 % was obtained for PET: ethanolamine ratio of 1:4 (w/w), with 4 h reaction time, at 160oC with sulfated polyborate as a catalyst. BHETA was characterized with FTIR, 1H,13C NMR, and DSC analysis. BHETA further gets reacted with dimer acid along with Ethylenediamine (EDA) at different molar ratios which produces polyesteramide (PEA) based hot melt adhesive (HMA). Thermal, mechanical, and rheological tests are performed and compared with traditional HMA. The effect on the properties of the hot melt adhesive, such as mechanical properties: tensile strength, shore D hardness, elongation at break; thermal properties: glass transition temperature (Tg), melting temperature (Tm), the heat of crystallization (Hc), crystallization temperature (Tc); adhesion properties: lap shear strength (LSS) and T-peel strength (TPS); rheological properties and degree of crystallinity were investigated. It was observed that the mechanical and thermal properties are increased by optimizing the concentration of BHETA. These HMA materials may have the capacity of being eco-friendly and have high adhesion properties.

Sulfated Polyborate Catalyzed Improved Synthesis of Enamines and Enaminones Based Intermediates of Imatinib, Nilotinib and Ocinaplon**

AbstractAn activation of methyl ketones or active methylenes and N, N‐dimethylformamide dimethyl acetal at 110 °C by sulfated polyborate under solvent‐free conditions has been developed for enamines and enaminones synthesis. Selected Brønsted acid, optimized reaction conditions, and easy separation method lead to 82–97 % yield, making this process cost‐effective and eco‐friendly. We chose boric acid for scale‐up activity in the interest of readers and industries. The optimized reaction condition was applied to demonstrate a 10 gram scale for the intermediate of Imatinib and Nilotinib with an 80 % from 3‐acetylpyridine. This method is extendable to produce Ocinaplon intermediate with 80.6 % yield using 4‐acetyl pyridine as starting material.

Sulfated polyborate catalyzed rapid and efficient electrophilic thiocyanation of activated arenes

This report describes a rapid, efficient, and environment-friendly methodology for electrophilic thiocyanation of activated arenes using sulfated polyborate as a Bronsted acid catalyst and H2O2 as a green oxidizer at 30 °C. The methodology was applied for activated arenes, including indoles and β-ketoesters, along with recyclability of aqueous quench was demonstrated for four cycles with no loss of catalytic activity. The key benefits of the method are a shorter reaction time, higher yields, and easy work-up under mild reaction condition.

Sulfated polyborate as Bronsted acid catalyst for Knoevenagel condensation

We have developed the use of Bronsted acid for Knoevenagel condensation. Sulfated polyborate has been used for efficient Knoevenagel condensation of aromatic, heterocyclic, α,β-unsaturated, and aliphatic aldehydes in the ecologically friendly ethanol: water (1:1) mixture as solvent at 70 °C. It took less time for certain aldehydes to react with active methylenes. The present method demonstrated significant benefits in terms of first-time use of Bronsted acid catalyst, mild reaction conditions, and better product yields.

Phthaloylation of amines, hydrazines, and hydrazides by N-substituted phthalimides using recyclable sulfated polyborate

An efficient, fast, and environmentally gentle protocol for phthaloylation of amines, hydrazines and hydrazides via transamidation is described. The current research focuses on the phthaloylation of alicyclic, aliphatic, aromatic, heterocyclic amines, hydrazines, and hydrazides. Reaction with N-substituted phthalimides was completed in about 30 minutes at 70 °C in DMSO as a solvent, resulting in higher yield of products, ease of workup, and recyclability of catalyst. In addition to this, transamidation of cinnamamide and benzamide was also successfully achieved.

Ultrasound promoted environmentally benign, highly efficient, and chemoselective N-tert-butyloxycarbonylation of amines by reusable sulfated polyborate

The sulfated polyborate catalyzed an efficient and chemoselective N-tert-butyloxycarbonylation of amines under ultrasonic irradiation is developed. A broad substrate scope has been demonstrated for N-Boc protection of various primary/secondary amines. It allows converting several aliphatic/aryl/heteroaryl amines, amino alcohol, aminoester, and chiral amines to their N-Boc-protected derivatives under solvent-free conditions with excellent yields. The protocol has several advantages such as easy catalyst, and product isolation, short reaction time, excellent yields, outstanding chemoselectivity, and catalyst recyclability, among others. This makes the process practicable, economical, and environmentally benign.

Expeditious and Highly Efficient One-Pot Synthesis of Functionalized Imidazoles Catalyzed by Sulfated Polyborate

The development of simple, elegant, and eco-friendly methods for preparing widely used organic compounds from readily available catalysts and reagents is one of the major goals of synthetic organic...

Sulfated polyborate-H2O assisted tunable activation of N-iodosuccinimide for expeditious mono and diiodination of arenes

Owing to both Lewis and Bronsted acid active sites on sulfated polyborate under homogenous conditions, we were keen on developing iodination protocol of arenes that can meet the requirement of regioselectivity and higher yield. The sulfated polyborate activates N-iodosuccinimide for mono iodination of highly activated substrates viz. phenols, anilines under anhydrous condition. Water tunes sulfated polyborate to generate more Bronsted acid sites resulting in rapid activation of NIS for diiodination. The protocol was equally applicable to diiodination of 4-hydroxyphenylacetic acid to synthesize 4-hydroxy-3,5-diiodophenylacetic acid, an intermediate of tiratricol, a thyroid treatment drug. This protocol was further integrated via one-pot sequential iodination and Sonogashira coupling to synthesize aryl acetylenes, building blocks for the synthesis of a variety of specialty chemicals, API, and natural products.

Solvent-free, Efficient Transamidation of Carboxamides with Amines Catalyzed by Recyclable Sulfated Polyborate Catalyst

Transamidation is a significant reaction in organic and medicinal chemistry. The amide is one of the most important functional groups used in organic transformations, and it is found in a wide vari...

Sulfated polyborate: A dual catalyst for the reductive amination of aldehydes and ketones by NaBH4

An efficient, quick, and environment-friendly one-pot reductive amination of aldehydes or ketones was developed. In ethanol at 70 °C, a imination catalyzed by sulfated polyborate and further reduced by sodium borohydride yields various amines. The present method has many significant benefits, including a shorter reaction time, excellent yields, and a hassle-free, straightforward experimental process. The reaction has a wide range of applications due to its flexibility, including secondary amine for reductive amination.

Sulfated Polyborate, a Novel Buffer for Low pH Mobile Phase on a Nonend Capped Stationary Phase in Reverse Phase Liquid Chromatography

Background: Sulfated Polyborate, a novel inorganic material primarily designed as a catalyst, has shown properties such as high solubility in organic solvents, low U.V. cut-off, and pKa ≈2.0, which suggests its potential as a mobile phase buffer for reverse-phase liquid chromatography. Objective: This study aims to substantiate the role of Sulfated Polyborate as mobile phase buffer for reverse-phase liquid chromatographic analysis of basic drugs with high pKa values viz. Bisoprolol fumarate, Timolol maleate, Verapamil hydrochloride, and Carvedilol. Methods: Solubilities, U.V. cut-offs, and pKa of Sulfated Polyborate were first experimentally confirmed. The behaviour of Sulfated Polyborate as mobile phase buffer at pH 3.0 was ascertained by varying the buffer concentration, flow rates, and percent organic modifier for elution of the four basic drugs on a non-end capped octyl silyl (C8) column. Similarly, the study was performed with KH2PO4 as a reference buffer. The column performance and conductometric measurements ascertained the impact of Sulfated Polyborate on the stationary phase. Results: Sulfated Polyborate and KH2PO4 buffers showed correlation coefficients of 0.99 and 1.00 for analyte retention factors for variation of buffer concentration and organic modifier composition, respectively. Peak symmetries and the number of theoretical plates were improved from > 2.0 to < 2.0 and ≈1000 to ≈3000, respectively, for variation in buffer concentrations. Similar Van Deemter plots indicated equivalency of Sulfated Polyborate and KH2PO4 buffers. The column performance and conductometric measurements depicted no adsorption on the stationary phase. Conclusion: The present study demonstrates Sulfated Polyborate as a novel buffer for analytes with higher pKa on reverse-phase liquid chromatography.

Sulfated polyborate as an eco-compatible solid acid catalyst for efficient and facile solvent-free synthesis of polyhydroquinolines

An environmentally viable, green and efficient protocol for the synthesis of polyhydroquinolines using sulfated polyborate catalyst have been developed by Hantzsch four-component condensation between aromatic aldehydes, dimedone, ammonium acetate and ethylacetoacetate or ethylcyanoacetate at 100 °C under solvent-free condition. The sulfated polyborate catalyst is characterized by FT-IR, XRD, SEM and EDAX techniques. The noticeable features of this methodology are mild Bronsted acidic nature of the catalyst, good to excellent product yields (85–94%), short reaction time (18–30 min), solvent-free condition, operational simplicity and applicability to a wide range of substrates (29 examples). This work deals with sulfated polyborate catalysed green and efficient solvent-free synthesis of polyhydroquinolines.

Sulfated Polyborate Catalyzed Selective Friedlander Annulation for Synthesis of Highly Functionalized Quinolines

The quinoline moiety is a privileged scaffold because of the wide spectrum of its biological activities. 1 , 2 Along with the Friedlander annulation, other procedures developed for the synthesis of...

Three-component, solvent-free synthesis of Betti base catalyzed by sulfated polyborate

In this work, efficient, mild, and eco-friendly procedure of 1-aminoalkyl-2-phenol/Betti base from one-pot three-component condensations of aldehyde, phenol, and morpholine in the presence of sulfated polyborate catalyst, under a solvent-free condition at 100 °C, is described. The key advantages of the present method are short reaction time, high yields, aqueous work-up procedure, low cost, stable, reusable catalyst, and solvent-free reaction conditions.

A Sulfated Polyborate Catalyst for the Synthesis of 1,5-Benzodiazepines

A Sulfated Polyborate Catalyst for the Synthesis of 1,5-Benzodiazepines

Synthesis of (Non)symmetrical Ureas Catalyzed by Sulfated Polyborate

Synthesis of (Non)symmetrical Ureas Catalyzed by Sulfated Polyborate

Environmentally Benign, Highly Efficient and Expeditious Solvent‐Free Synthesis of Trisubstituted Methanes Catalyzed by Sulfated Polyborate

AbstractHighly efficient and environmental friendly one‐pot synthesis of trisubstituted methanes form aldehydes and heteroaryls with sulfated polyborate catalyst was conveniently performed under solvent‐free grinding condition at room temperature. The catalyst is recyclable up to five consecutive runs and column chromatography‐free isolation of the trisubstituted methanes in excellent yields was achieved.

Synthesis of Isoxazole-5-(4H)-ones with Sulfated Polyborate

Synthesis of Isoxazole-5-(4H)-ones with Sulfated Polyborate

An efficient, environmentally benign, and solvent-free protocol for the synthesis of 4-substituted 1,5-benzodiazepines catalyzed by reusable sulfated polyborate

An efficient and environmentally benign method has been developed for the one-pot solvent-free synthesis of 4-substituted-1,5-benzodiazepines via three-component reaction of o-phenylenediamine, dimedone with a variety of aldehydes catalyzed by sulfated polyborate. The major advantages of the present method are good to excellent yields, shorter reaction time, simple experimental procedure, easy workup, solvent-free reaction condition, recyclability of the catalyst and ability to tolerate a variety of functional groups which gives economical as well as ecological rewards.

Sulfated polyborate-catalyzed efficient and expeditious synthesis of (un)symmetrical ureas and benzimidazolones

The excellent catalytic potential of sulfated polyborate is utilized in the synthesis of (un)symmetrical ureas and benzimidazolones by heating amines or substituted OPDA and urea or N-phenylureas under a solvent-free condition at 120 °C is described. The key advantages of the present protocol are phosgene-free, and other hazardous reagents or organic solvent free, high reaction rates and yields, simple workup procedure, and recyclability of the catalyst.