Polyphosphoric Acid Research Articles (Page 1)

Coumarin-benzimidazole hybrids: Design, synthesis and identification of potential anticancer agents.

Research into breast cancer treatments is progressing and contemporary, particularly with a focus on tyrosine kinase receptors, which are crucial for regulating various cellular functions. The chemistry of the 2-pyridone scaffold allows for the creation of diverse molecular structures. Converting 2-pyridone into a hydrazide form enhances its biological activity. Using polyphosphoric acid enables effective electrophilic attacks, resulting in various polycyclic compounds as naphthyridine and pyridopyrimidine. These compounds are being evaluated as potential tyrosine kinase inhibitors, refined through the “rule of five” to improve their drug-like properties. In assessing their cytotoxicity, the MTT assay was performed on MCF-7 cell lines using different concentrations. Compounds 2, 4, 8, 10, 12, and 16 have demonstrated notable IC50 values, surpassing the efficacy of doxorubicin, which has an IC50 value of 11.86 µM. Among these compounds, 2, 4, and 8 are particularly distinguished by their favorable molecular docking simulation profiles. These compounds represent promising candidates for further investigation in the treatment of breast cancer.

This study examines the rheology and fiber formation of poly(2,5(6)-benzimidazole) (ABPBI) solutions in polyphosphoric acid (PPA) at 12.5 wt%. These solutions exhibit typical features of associative polymer systems, such as pronounced shear thinning and high elasticity. The activation energy of the viscous flow increases with the polymer concentration, reaching 29 kJ/mol at 12.5 wt%, but remains significantly lower than in phosphoric acid solutions. This indicates more efficient solvation and chain mobility in PPA. A comparison with two superbasic solvent systems further highlights the critical role of the solvent nature in flow mechanisms and associative interactions. Model coagulation experiments revealed how the non-solvent composition controls the fiber morphology and solidification. Under optimized conditions, homogeneous monolithic fibers with good mechanical performance were obtained. These findings provide new insight into the physicochemical principles of ABPBI fiber formation and establish PPA as a promising solvent for producing high-performance fibers.

ABSTRACTThis study aimed to optimize the rheological properties and compatibility of waste low‐density polyethylene (LDPE)/plasticizer diisononyl phthalate (DINP) modified asphalt using furfural extraction oil (FEO) and polyphosphoric acid (PPA). Conventional performance and temperature scanning tests initially determined the optimum dosage ranges of FEO and PPA. The effects of FEO and PPA on the properties of waste LDPE/plasticizer DINP‐modified asphalt were investigated using dynamic shear rheology (DSR), multi‐stress creep recovery (MSCR), bending beam rheometer (BBR), segregation test, and microscopic tests. The results indicated that 1.2% FEO and 0.5% PPA significantly enhanced the high‐temperature rheological properties of waste LDPE/plasticizer DINP‐modified asphalt, with minimal impact on the low‐temperature rheological properties. The fluorescence microscopy (FM) analysis and scanning electron microscopy (SEM) test revealed that the addition of FEO and PPA resulted in a more uniform dispersion of LDPE within the asphalt. Fourier transform infrared spectroscopy (FTIR) spectra demonstrated that the incorporation of FEO and PPA introduced new characteristic peaks in the infrared spectra of the waste LDPE/plasticizer DINP‐modified asphalt, suggesting that chemical modification had occurred. FEO and PPA are added to the waste LDPE/plasticizer DINP‐modified asphalt to improve its rheological properties and compatibility, which is of significance for promoting the construction of green transportation.

Facile and concise procedures for the construction of indole fused N-heterocyclic systems were described. A series of benzo-, pyrido-, thieno-, naphtho-fused azepinoindolones and indolo-azepinoquinolinones has been prepared starting from indol-2-acetic acids. The required starting carboxylic acids 3a–e were readily obtained by the N-arylations of indoleacetic acid 1 with various aromatic halides 2a–e. Subsequent carboxylic acids were esterified, followed by the addition of Grignard reagents to afford the corresponding indole-based alcohols 5a–e. The key step in this protocol is the Friedel–Crafts cyclisations of these precursors promoted by AlCl3/CH3NO2 or trifluoromethanesulfonic acid (TfOH) or polyphosphoric acid (PPA) catalysts to form the desired condensed indoles in moderate to good yields.

Chemical additives and polymeric materials, selected for their compatibility and ability to improve asphalt's performance in demanding environments. Key additives, including Polyphosphoric Acid (PPA), Polyvinyl Acetate (PVAC) beads, Maleic Anhydride (MA), and Ethylene Vinyl Acetate (EVA) resin, were mixed in precise ratios with the asphalt binder. These additives were chosen to evaluate their effects on crucial performance indicators, such as the Penetration Index (PI) and activation energy, which measure the material’s thermal stability, flexibility, and resistance to deformation. Results demonstrated that the addition of these materials significantly increased the asphalt’s activation energy by up to 45.44%, enhancing its resistance to temperature fluctuations and providing better stability under various environmental stresses. The Penetration Index (PI) also improved notably, indicating that modified asphalt exhibits greater durability and reduced susceptibility to cracking or deformation under thermal changes. These enhancements contribute to lower road maintenance requirements and support greater energy efficiency in asphalt production and application processes. Compared to neat asphalt, the modified asphalt exhibited superior thermal stability, mechanical resilience, and overall performance, making it suitable for use in diverse climatic conditions. This study provides valuable insights into sustainable asphalt modification techniques, emphasizing the role of polymer and chemical additives in extending pavement lifespan and reducing environmental impact through improved material properties.

ABSTRACTRed mud (RM), a solid waste produced in the aluminum industry, poses significant risks to human health and the environment during disposal. To promote its resourceful utilization, this study uses polyphosphoric acid (PPA) as a crosslinking agent to chelate metal ions in RM, forming a hybrid material (RM‐PPA), which is then applied as a modifier for asphalt binder. The impact of RM‐PPA on asphalt properties was evaluated using microstructural characterization, mechanical performance testing, and software simulations. Results showed that the surface of RM was modified into an interlocking flake‐like structure, enhancing interfacial adhesion with asphalt. This improved the mechanical performance and high‐temperature stability of the asphalt. At an ambient temperature of 46°C, asphalt modified with 5 wt% RM‐PPA exhibits optimal performance. Its complex modulus (G*) was 289% higher than that of the base asphalt, while its strain recovery rate (R) improved by 148% and 155% under 0.1 and 3.2 kPa, respectively. Molecular dynamics simulations confirm strong adsorption interactions between RM modification products and asphalt molecules. This enhanced interfacial interaction plays a crucial role in addressing material interface defects.

Polyphosphoric acid (PPA)-polyborate as a solid acid new catalyst was prepared by the reaction between PPA and polyborate. 2H-Indazolo[2,1-b]phthalazine-1,6,11(13H)-triones were synthesized under solvent-free conditions through one-pot tri-component reaction involving substituted aryl aldehydes, phthalhydrazide, and dimedone in the presence of PPA-polyborate catalyst. The main advantages of this study are good to excellent yields, use of less hazardous chemical, shorter reaction times, gentler reaction conditions, reduced chemical waste, increased energy efficiency, environmentally friendly pathways, and straightforward work-up procedures.. KEYWORDS :Polyphosphoric acid-polyborate, Multi-component reactions, Solvent-free reaction, 2H-indazolo[2,1-b] phthalazine-triones, Homogeneous solid acid catalyst.

Synthesis of 2,4-Disubstituted Quinolines by the Reaction of Propargylic Alcohols with Anilines in a Polyphosphoric Acid Medium

The rapid rise in greenhouse emissions has intensified climate change, highlighting the urgent need to assess its impact on critical infrastructure. Asphalt pavements, are particularly vulnerable to the stresses caused by climate change including rising temperatures and shifting precipitation patterns. The paper examines the impact of global warming on asphalt pavements using the Prophet model under three scenarios, focusing especially on variations in the performance grade of bitumen obtained from 34 synoptic stations of Iran. This study outlines types and precise of additives needed to meet evolving bitumen requirements through 2060. To promote sustainability in Iran’s bitumen industry, this study includes a detailed economic and environmental analysis of additive production, transportation, and blending with existing bitumen sources. Findings suggest in 2060, Iran’s bitumen demands can be met by producing PG 82 -16 and PG 76 -28 grades. The results showed that using styrene-butadiene-styrene (SBS) instead of crumb rubber (CR) led to a 46% increase in carbon dioxide emissions and a 1700% increase in costs. In contrast, replacing polyphosphoric acid (PPA) with crumb rubber reduced costs by 56%, while causing a 13% increase in carbon dioxide emissions. This study provides an innovative hybrid framework for temperature prediction under different scenarios using a machine learning model, forecasting bitumen performance grading, and evaluating the environmental impacts of various additives to enhance the performance of existing bitumens.

Investigating the modifying mechanism of polyphosphoric acid on asphalt: From the colloidal component perspective

In this work, a one-step method synthesis of lactide is reported instead of the traditional two-step method. The selection of a suitable acid catalyst polyphosphoric acid and optimization of reaction conditions result in a yield of 97%. Moreover, this new one-step strategy eliminates the need for metal catalysts and does not require high-temperature conditions, thereby avoiding the issue of racemization. The simple one-step strategy offers a combination of efficiency, sustainability, and product quality improvements, making it a modern, practical approach to lactide synthesis.

Abstract Breast cancer is the most common type of cancer worldwide. In 2023, the World Health Organization (WHO) reported that 2.3 million women were diagnosed with breast cancer, leading to 670, 000 deaths. Furthermore, the incidence rates of breast cancer have been rising at 3% each year. Overexpression of COX-2 in breast cancer tissues is associated with poor prognosis, including higher tumor grade, increased metastatic potential, and resistance to therapy. Selective COX-2 inhibitors have demonstrated potential in reducing tumor growth in preclinical and some clinical studies. These inhibitors may also enhance the effectiveness of chemotherapy and radiotherapy. The benzimidazole nucleus is a valuable subunit for the development of pharmaceuticals and biologically relevant molecules. Tetrahydropyridine (THP)analogs are compounds with diverse biological activities, including analgesics, anti-inflammatory agents, and chemotherapeutic agents. Our previous research findings indicated that the THP derivatives exhibited COX-2 inhibition and demonstrated anti-inflammatory effects in rat paw edema assays. The pharmacological activities of THP derivatives depend on the nature of the substituents in the THP ring system. The incorporation of a benzimidazole moiety may enhance the biological activity of these THP derivatives. Thus, the design and synthesis of novel series of benzimidazole-THP derivatives with potential anticancer and anti-inflammatory activities were initiated. In the current investigation, we synthesized numerous analogs maintaining the N-(5-(1H-benzo[d]imidazol-2-yl)-3, 6-dihydropyridin-1(2H)-yl)benzamide/benzene sulfonamide having modifications on the phenyl ring. We expect that these structural modifications would affect the compounds electron density, lipophilicity and the compounds steric configurations. The starting material 2-(pyridin-3-yl)-1H-benzo[d]imidazole was obtained by the reaction of nicotinic acid, 1, 2-phenyldiamine and polyphosphoric acid by stirring in an oil bath at 180o C for 2 h. N-Amination of substituted 2-(pyridin-3-yl)-1H-benzo[d]imidazole by an aminating agent O-(mesitylsulfonyl)hydroxylamine (MSH), followed by ylide formation and further reduction yielded the desired substituted N-(5-(1H-benzo[d]imidazol-2-yl)-3, 6-dihydropyridin-1(2H)-yl)benzamide derivatives. Final compounds were analyzed via NMR spectroscopy, IR and elemental analysis. The analogs were evaluated for through docking studies. Two products showed significant anti-inflammatory and anti-breast cancer activities. Citation Format: Kinfe Ken Redda, Madhavi Gangapuram, Absera W. Haile, Suresh Eyunni. Synthesis of substituted benzimidazole tetrahydropyridines as anti-breast cancer agents [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2025; Part 1 (Regular Abstracts); 2025 Apr 25-30; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2025;85(8_Suppl_1):Abstract nr 5742.

Polyphosphoric acid (PPA), a chemical modifier widely used in petroleum asphalt, results in significant performance improvements. However, its effectiveness for modified emulsified asphalt has not yet been thoroughly verified. This study aims to investigate the emulsification properties, rheological characteristics, compatibility, and modification mechanisms of PPA-modified emulsified asphalt and validate the feasibility of applying PPA for modification. Initially, PPA-modified emulsified asphalt was prepared at different dosages (0%, 0.5%, 1.0%, 1.5%, and 2.0%), and its emulsification characteristics, including evaporation residue properties and storage stability, were evaluated. Subsequently, the rheological performance and compatibility of PPA-modified emulsified asphalt at various temperatures were evaluated using a dynamic shear rheometer. Finally, Fourier transform infrared spectroscopy (FTIR) and fluorescence microscopy (FM) were utilized to investigate the effects of PPA modification on the chemical composition and microscopic characteristics of emulsified asphalt. The results indicated that, with increasing PPA dosage, the softening point of modified emulsified asphalt initially decreased and then increased, while penetration and ductility first increased and then decreased, accompanied by reduced storage stability. Furthermore, PPA modification can enhance the high-temperature stability, fatigue properties, and low-temperature performance of emulsified asphalt, but the effectiveness depended on the dosage of PPA. Specifically, optimal compatibility of modified emulsified asphalt was achieved at a PPA dosage of 1.0%. Notably, PPA underwent hydrolysis within the emulsified asphalt system, leading to modification mechanisms distinct from those observed in base asphalt modification. At a PPA dosage of 1.0%, asphalt particles within the emulsified asphalt exhibited the most uniform distribution. Conversely, excessive PPA dosage (e.g., 2.0%) caused significant particle aggregation, consequently weakening the modification effect.

Highly modified asphalt binders (HiMAs) enhance pavement durability, though their polymer and additive content raises environmental concerns. To optimise durable asphalt layers, 12 HiMAs, varying in composition and processing, were evaluated using penetration (EN 1426), softening point (EN 1427), storage stability (EN 13399), and Multiple Stress Creep and Recovery (MSCR, EN 16659) tests, including the ElaStiLe protocol. Results indicate that compositional variations minimally affect penetration and softening point, but significantly influence stability, workability, and rheological behaviour. Thus, HiMAs produced with 8.0% high-vinyl SBS polymer, 0.5% polyphosphoric acid (PPA), and 0.1% sulphur, subjected to an extended 240-minute digestion, performed better than conventional polymer-modified binders.

Abstract Poly(benzobisthiazoles) with a flexible moiety are synthesized through the polycondensation process involving 2,5‐diamino‐1,4‐benzenedithiol dihydrochloride and either cyclohexane‐1,4‐dicarboxylic acid or a combination of cyclohexane‐1,4‐dicarboxylic acid and terephthalic acid in polyphosphoric acid. The inherent viscosity of these poly(benzobisthiazoles) is measured at 30 °C in methanesulfonic acid, ranging from 1.0 to 1.39 dL/g. The polymer structures are confirmed through elemental analysis and spectroscopic comparison with appropriate model compounds. Thermal stability is assessed using thermogravimetric analysis (TGA) in a nitrogen atmosphere, and the glass transition temperature is determined via differential scanning calorimetry (DSC). Interestingly, the cyclohexyl poly(benzobisthiazole) exhibits lower stability at elevated temperatures compared to poly(p‐phenylene bisthiazole) PBZT.

A literature review of modern chemical methods for modifying road bitumen has been conducted, focusing on their popularity and the nature of their impact on binder properties. Sulfur, polyphosphoric acid, maleic anhydride, thermosetting resins (such as phenol-formaldehyde, epoxy, polyester, etc.), and polymers are the most commonly used chemical modifiers in road construction practices. The method of producing bituminous materials with varying penetration levels through the chemical modification of oil residues with formaldehyde has been considered. All bituminous materials produced via chemical modification demonstrate better homogeneity during high-temperature storage compared to those modified through physical methods due to the chemical interaction between a reactive modifier and bitumen. It has also been shown that chemical modifiers are often used in combination with physical modifiers to enhance their effectiveness.

The viscoelastic behavior of asphalt mixtures is a crucial consideration in the analysis of pavement mechanical responses and structural design. This study aims to elucidate the molecular structure and component evolution trends of polyphosphoric acid (PPA)/styrene butadiene styrene block copolymer (SBS)/styrene butadiene rubber copolymer (SBR) composite modified asphalt (CMA) under rolling thin film oven test (RTFOT) and pressure aging (PAV) conditions, as well as to analyze the viscoelastic evolution of CMA mixtures. First, accelerated aging was conducted in the laboratory through RTFOT, along with PAV tests for 20 h and 40 h. Next, the microscopic characteristics of the binder at different aging stages were explored using Fourier-transform infrared spectroscopy (FTIR) and gel permeation chromatography (GPC) tests. Additionally, fundamental rheological properties and temperature sweep tests were performed to reveal the viscoelastic evolution characteristics of CMA. Ultimately, the viscoelastic properties of CMA mixtures under dynamic loading at different aging stages were clarified. The results indicate that the incorporation of SBS and SBR increased the levels of carbonyl and sulfoxide factors while decreasing the level of long-chain factors, which slowed down the rate of change of large molecule content and reduced the rate of change of LMS by more than 6%, with the rate of change of overall molecular weight distribution narrowing to below 50%. The simultaneous incorporation of SBS and SBR into CMA mixtures enhanced the dynamic modulus in the 25 Hz and -10 °C range by 24.3% (AC-13), 15.4% (AC-16), and reduced the φ by 55.8% (AC-13), 40% (AC-16). This research provides a reference for the application of CMA mixtures in the repair of pavement pothole damage.

Study on the adhesion properties of SBS modified asphalt-aggregate with polyphosphoric acid and sugarcane bagasse fiber under salt erosion

The three dinaphthylketone constitutional isomers, 1,1′-NA2CO, 1,2′-NA2CO, and 2,2′-NA2CO, have been subjected to Friedel–Crafts Acylation (polyphosphoric acid (PPA), 90–300°C, 12 h) and Scholl reaction (AlCl3/NaCl, 120–300°C, 4 h). The resulting product mixtures are analyzed by NMR and separated by column chromatography. The starting ketones and the products have been calculated with DFT, B3LYP/6-311G**, to support analysis of the reaction mechanisms. The three dinaphthyl ketones have three, four, and three E,Z-conformations, which may potentially give ten Scholl reaction products by ortho-ortho, ortho-peri, and peri-peri couplings. In PPA, the products formed at relatively low temperatures are due to Scholl reactions of the starting ketones. At higher temperatures, naphthalene is formed and Friedel Crafts acyl rearrangements (FCAcRs) 1,1′-NA2CO → 1,2′-NA2CO → 2,2′-NA2CO are observed. At high temperatures, additional Scholl products show that complex multi-step reactions occur including FCAcRs in both directions and cyclic FCAcRs of Scholl products. The reactions in AlCl3/NaCl are highly selective, giving only the 6-ring Scholl cyclization products 13H-dibenzo[a,i]fluoren-13-one and 7H-benzo[hi]chrysen-7-one (BhiCO) and 7H-benzo[de]naphthacen-7-one (BdeNCO). Up to 240°C 1,1′-NA2CO forms BhiCO and up to 220°C 1,2′-NA2CO forms BdeNCO. At higher temperatures, both polycyclic aromatic ketones are formed from each of the three dinaphthyl ketones indicating FCAcRs. The detailed analysis of the experimental data in combination with the DFT calculations shows that FCAcRs are reactions in both directions in PPA and AlCl3/NaCl, substantiating Gore’s 1955 proposition that the Friedel–Crafts acylation reaction of reactive aromatic hydrocarbons is a reversible process. The lower onset temperatures and selectivity of cyclization products suggest lower activation energies for Scholl reactions as compared to FCAcRs in PPA and even more pronounced in AlCl3/NaCl. The common network of reaction pathways underlying the reactions in both media highlights the linkage between Friedel–Crafts acyl rearrangements and Scholl reactions.Graphical