Acidic Properties Research Articles

Selectivity control in catalytic glucose dehydration using iron- and tungsten-modified ZSM-5 catalysts

The conversion of lignocellulosic biomass into valuable chemicals and fuels has received considerable attention owing to the issues related to global warming. 5-Hydroxymethylfurfural (HMF) is a versatile lignocellulose-derived platform chemical used in a wide range of high-value bioproducts. However, the HMF production is completed with polymerization by which humins are inevitably formed as a by-product. Recently, the potential of humins for various applications has been explored. In this study, a series of ZSM-5 zeolite catalysts modified with iron (Fe) and tungsten (W) were used to selectively control glucose dehydration to HMF and humins. The zeolite catalysts possessing tunable bifunctional Brønsted–Lewis acid characteristics were prepared through pretreatment using a diluted nitric acid solution, followed by metal impregnation. The impregnation of Fe into ZSM-5 induced the formation of highly dispersed extraframework isolated Fe3+ ions and Fe2O3 species, which increased the content of Lewis acid sites. The W species added to ZSM-5 existed in the form of Si–OH–W linkages and polytungstates with moderate-to-strong Brønsted acidity. The selective synthesis of HMF was efficiently performed over the Fe-modified ZSM-5 catalysts. Furthermore, the W-modified catalysts exhibited potential application as novel catalysts for the selective production of humins. The controlled selectivity to each product depended on the acidic properties and Lewis/Brønsted acidity ratio of the catalysts as well as the transition metal-dependent characteristics of the Brønsted and Lewis acid sites.

Acidity and stability of Nb(V) active sites doped in SBA-15 and ZrSBA-15: A DFT study

Mesoporous silicas are of great interest in heterogeneous catalysis due to the structural characteristics of their pores and the adjustable catalytic properties that arise from incorporating heteroatoms. The substitution of Zr and Nb into SBA-15 introduces active sites into the material, rendering it a potential catalyst for acid catalysis reactions. However, discussions regarding the acid properties and metal-support interactions in amorphous silicas functionalized with metals are limited in computational chemistry. This study aims to determine the acid strength and charge transfer effects between Zr(IV) and Nb(V) species in mesoporous silica by proposing a representative SBA-15 cluster of type 5–6. Density Functional Theory (DFT) simulations were conducted using the B3LYP/6-31G(d,p)/def2TZVP levels. The model successfully replicated trends from larger clusters, demonstrating that the more grafted onto the silica structure (i.e. have more Si-O-M bonds), the greater the acid strength of the active site. Additionally, it was found that ZrSBA-15 structures are more stable than NbSBA-15 and possess higher acid strength, a trend supported by experimental observations. The results also suggest that Nb(V) species are more effectively stabilized in ZrSBA-15 than SBA-15, likely due to the presence of Zr(IV) centers in ZrSBA-15. This research contribute to a better understanding of how the support affects the stabilization of active phases, paving the way for the rational design of silica-based heterogeneous catalysts.

A novel bio-based ferric flame retardant effectively improving the flame retardancy and mechanical properties of polylactic acid

PTDF is prepared by a convenient ionic reaction of phytic acid, terephthalic dihydrazide and iron salts in water. PTDF has high phosphorus and nitrogen content and good thermal stability, which can effectively improve the flame retardancy of PLA. PTFE is an anti-drip agent and is often used to improve the flame retardancy of PLA together with flame retardants. The addition of 4 wt% PTDF and 0.1 wt% PTFE made PLA reach V-0 flame retardant grade from non-flame retardant, and the oxygen index increased from 19.5 % to 24.5 %. With the increase of PTDF content, the performance of PLA improved significantly. The peak heat release rate (PHRR) and THR of PLA/6PTDF composites decrease by 27.4 % and 16.2 %, respectively, and the flame retardant index FRI increase by 232 %, showing excellent flame retardant efficiency. 6 wt% PTDF can increase the crystallinity of PLA by 25.9 %, tensile strength, maximum force required for impact fracture and notch impact strength by 12 %, 37 % and 129 %, respectively, and effectively improve the mechanical properties and toughness of the composite. The bio-based flame-retardant PLA/PTDF composites reported in this paper can be applied to office equipment.

Synergistic effect of Co-MOF/epoxy modified tannic acid/ammonium polyphosphate on flame retardancy, anti-melt dripping and mechanical properties of polylactic acid

Achieving flame retardancy and anti-dripping properties in polylactic acid (PLA) while preserving its mechanical integrity remains a significant challenge. In this study, a novel organic ligand rich in phosphorus (P) and nitrogen (N) was synthesized and coordinated with Co2+ions to form a cobalt-based metal–organic framework (Co-MOF) with a multilayer mesoporous structure, acting as an effective carbonization agent. This Co-MOF was then compounded with epoxy-modified tannic acid (eTA) and ammonium polyphosphate (APP) to create a synergistic flame-retardant system for PLA (PLA/MAT). The Co-MOF provides numerous active sites for catalytic oxidation, promoting the formation of a uniform, hill-like expanded carbon layer. During pyrolysis, the Co-MOF and APP yield cobalt oxides and polyphosphates, which catalyze the dehydration of PLA and eTA, facilitating carbonization and forming a continuous, dense protective layer. Consequently, the PLA/MAT system exhibits both robust mechanical properties and excellent flame retardancy, as demonstrated by a limiting oxygen index (LOI) of 27.0 % and a UL-94 V-0 rating, with no melt dripping observed during combustion tests. This work offers a novel approach for enhancing the flame retardancy and anti-dripping performance of PLA, with potential applications in engineering, electronics, and the automotive industry.

Effect of legume proteins on the structure and digestibility of wheat starch-lauric acid complexes

The effect of legume proteins (soy protein (SP), chickpea protein (CP) and peanut protein (PP)) on the properties of wheat starch-lauric acid (WS-LA) system and its intrinsic mechanism were investigated. RVA, digestion experiment and TGA results showed that legume proteins prompted the viscosity peak formation during cooling stage and increased anti-digestion and thermal stability of WS-LA system. FT-IR, Raman, XRD and 13C NMR results indicated that legume proteins improved the long-range and short-range ordering degree and single-helix structure of WS-LA system. SP had greater influence on the properties of WS-LA system than that of CP and PP. Proteins with high solubility, emulsifying properties and β-sheet content were conducive to starch-based complexes formation. Molecular dynamics simulation results indicated that major forces for WS-LA-SP formation were hydrogen bonding and van der Waals forces. This study offered crucial information on starch-fatty acid-protein complexes formation for proteins selection in starch-based products development.

Freeze-drying-induced mutarotation of lactose detected by Raman spectroscopy

Freeze-drying enables delicate, heat-sensitive biomaterials to be stored in a dry form even at room temperature. However, exposure to physicochemical stress induced by freeze-drying presents challenges for maintaining material characteristics and functionality upon reconstitution, for which reason excipients are required. Although wide variety of different excipients are available for pharmaceutical applications, their protective role in the freeze-drying is not yet fully understood. In this study, our aim was to use molecular dynamics simulations to screen the properties of different sugars and amino acids, which could be combined with plant-based nanofibrillated cellulose (NFC) hydrogel to provide protective matrix system for future freeze-drying for pharmaceuticals and biologics. The changes in the NFC-based formulations before and after freeze-drying and reconstitution were evaluated using non-invasive Timegate PicoRaman spectroscopy and traditional characterization methods. We continued to the freeze-drying with the NFC hydrogel formulations including lactose with and without glycine, which showed the highest attraction preferences on NFC surface in silico. This formulation enabled successful freeze-drying and subsequent reconstitution with preserved physicochemical and rheological properties. Raman spectroscopy gave us insights of the molecular-level changes during freeze-drying, especially the mutarotation of lactose. This research showed the potential of integrating in silico screening and non-invasive spectroscopical method to design novel biomaterial-based formulations for freeze-drying. The research provided insights of the molecular-level interactions and orientational changes of the excipients, which might be crucial in future freeze-drying applications of pharmaceuticals and biologics.

Cross-linked proton exchange membrane covalently bonded with silicotungstic acid for enhanced proton conductivity

Proton exchange membranes with cross-linked structures often showed excellent mechanical and chemical stability, but their water absorption and proton conductivity were restricted. This study reported a convenient and efficient thermal cross-linking reaction of sulfonic acid groups and benzene rings using dimethyl sulfoxide and sulfolane mixed solvents to prepare the membrane. To further illustrate, phenoxyphenyl-attached silicotungstic acid (POP-SiWA) was incorporated in the sulfonated poly(ether ether ketone) membrane and covalently bonded with the polymer by thermal cross-linking reaction. The immobilization ratio for the membranes prepared with 10∼30 wt% POP-SiWA addition was 88.0–63.7%. The modified membranes exhibited high hydrophilicity and improved proton conductivity under hydrated or low relative humidity conditions due to the strong acidity and water-retaining properties of silicotungstic acid. Specifically, the proton conductivity of the modified membrane with 30 wt% POP-SiWA reached 212 mS/cm. It exhibited a fuel cell power density of 629 mW/cm2 at 80 °C and 100% relative humidity, which were 1.90 and 2.67 times higher than the pristine membrane.

A Review on Anticancer Properties of Chebulagic Acid from Terminalia chebula

A Review on Anticancer Properties of Chebulagic Acid from Terminalia chebula

Impact of the Ceria Particle Oxidation State on the Collecting Properties of Sophorolipids and Benzohydroxamic Acid.

The search for environmentally friendly alternatives to petroleum-based reagents in mineral processing requires fundamental studies of novel chemicals in model mineral systems. In this study, we evaluate the potential of acidic (ASL) and lactonic sophorolipids (LSL) as collectors in the froth flotation of ultrafine ceria, which serves as a model rare earth mineral (REM). We compare these two biosurfactants to a conventional petroleum-based collector, benzohydroxamic acid (BHA), in the flotation of ceria against hematite and quartz particles. Our research shows the effect of the oxidation state of ceria on its interaction with both conventional and sophorolipid collectors, which can serve as a tool for selective separation in the applied chemistry of froth flotation. It was found that the affinity of the metal oxides to the biosurfactants at pH 4 decreases in the order of α-Fe2O3 > CeO2 (red) > CeO2 (ox), where the best collector of ultrafine ceria against hematite is BHA. To support our findings, we study collector-mineral interactions through mini-flotation tests, adsorption density, contact angle, and zeta potential analyses. In addition, we evaluate the stability of the froth during the flotation of the biosurfactants. Our results indicate that modifying the oxidation state of ceria and using sophorolipids hold promise for the sustainable flotation of REM.

Does cannula's size alter rheological properties of hyaluronic acid filler?

This study evaluated the rheological properties of various hyaluronic acid (HA) gels after passing through different-sized cannulas (22-G and 25-G). Five commercial brands of highly crosslinked HA fillers were analyzed: (A) Rennova® Ultra Deep, (B) Restylane® Lyft, (C) Hialurox® - Ultra Lift, (D) Belotero® Volume, and (E) E.P.T.Q S500. Rheological characterization was conducted using an automated controlled stress rheometer. The rheological properties of the fillers were assessed both before and after passing through the cannulas. Each filler brand and cannula size was tested three times by a researcher who was blinded to the commercial brands. For data analysis, frequencies of 0.1, 0.5, and 2 Hz were employed. The rheological properties (storage modulus [G'] and loss modulus [G"]) of the high-crosslink HA fillers did not change after being passed through cannulas of different sizes (22-G and 25-G) (p > 0.109) compared to baseline measurements (no cannula). Furthermore, all fillers displayed desirable solid-like, volumizing behavior at low frequencies and strain amplitudes (<10 %). Under physiologically relevant conditions for skin and facial applications, the cannula size did not alter the rheological properties of high crosslink HA fillers.

INFLUENCE OF SEA BUCKTHORN EXTRACT POWDER ON PHYSICOCHEMICAL, STRUCTURAL AND MECHANICAL PROPERTIES OF MINCED MEAT MINCE

The article examines the effect of sea buckthorn extract powder on the physico-chemical properties of minced meat. One of the key aspects of the study is the active acidity of the minced meat, which directly depends on the concentration of the added sea buckthorn powder. According to the results, an increase in the content of sea buckthorn in minced meat leads to a decrease in the pH value, which can help reduce the shelf life of the product. The optimal dosage was determined by 4-5% of sea buckthorn powder, which provides a balance between improving properties and maintaining organoleptic characteristics.The effect of the powder on the moisture-retaining ability of minced meat was also investigated. It has been shown that an increase in the amount of sea buckthorn powder initially improves moisture binding, but when a certain threshold is exceeded (more than 10%), this property begins to decrease. Thus, it is important to consider the dosage in order not to worsen the quality of the final product.Another important parameter is the shear stress limit. Studies have shown that at the initial stage of adding sea buckthorn, this indicator remains stable, but with prolonged stirring it begins to decrease, which is associated with a change in the structure of the minced meat and a decrease in its plasticity. The optimal mixing time is 3-5 minutes, which ensures the achievement of the required consistency and prevents the destruction of the structural and mechanical characteristics of the product.Thus, the addition of sea buckthorn powder to minced meat has a significant effect on acidity, moisture content and mechanical properties, while it is important to accurately observe the concentration and technological modes to achieve optimal product quality.

Aqueous Compatible Post-Synthetic On-Column Conjugation of Nucleic Acids Using Amino-Modifiers.

Nucleic acid conjugation methodologies involve linking the nucleic acid sequence to other (bio)molecules covalently. This typically allows for nucleic acid property enhancement whether it be for therapeutic purposes, biosensing, etc. Here, we report a streamlined, aqueous compatible, on-column conjugation methodology using nucleic acids containing a site-specific amino-modifier. Both monophosphates and carboxylates were amenable to the conjugation strategy, allowing for the introduction of a variety of useful handles including azide, aryl, and hydrophobic groups in DNA. We find that an on-column approach is superior to post-synthetic template-directed synthesis, mainly with respect to product purification and recovery.

Comparative Study of PtM (M=Cu, Zn, Ga, Mn, Fe, In, Ce) Bimetals on Zincosilicate for Propane Dehydrogenation Reaction.

Silicoaluminate zeolites have relatively strong Brönsted (B) acid properties that can easily lead to deep cracking reactions, making them less favourable as carriers for propane dehydrogenation. Here, we utilise zincosilicate zeolite with less B-acid produced by the introduction of the heteroatom Zn into the framework as a carrier, followed by simultaneous ion exchange (IE) of M monometallic or PtM bimetallic (M = Cu, Zn and Ga, etc.). The optimized PtZn/Zn-4 exhibits a superior propane dehydrogenation performance over PtCu/Zn-4 and PtGa/Zn-4, which can achieve a propane conversion of about 30% in a pure propane atmosphere at 550 °C and can be operated for at least 168 h without significant deactivation. Characterization techniques such as spherical aberration corrected transmission electron microscopy, in situ X-ray photoelectron spectroscopy, and in situ diffuse reflectance infrared fourier transform spectroscopy with different gas adsorptions are used to investigate these PtM@zeolite catalysts in order to deepen the understanding of acid site identification, promoter effect and catalysis.

Multifaceted Properties of Usnic Acid in Disrupting Cancer Hallmarks.

Cancer, a complex group of diseases marked by uncontrolled cell growth and invasive behavior, is characterized by distinct hallmarks acquired during tumor development. These hallmarks, first proposed by Douglas Hanahan and Robert Weinberg in 2000, provide a framework for understanding cancer's complexity. Targeting them is a key strategy in cancer therapy. It includes inhibiting abnormal signaling, reactivating growth suppressors, preventing invasion and metastasis, inhibiting angiogenesis, limiting replicative immortality, modulating the immune system, inducing apoptosis, addressing genome instability and regulating cellular energetics. Usnic acid (UA) is a natural compound found in lichens that has been explored as a cytotoxic agent against cancer cells of different origins. Although the exact mechanisms remain incompletely understood, UA presents a promising compound for therapeutic intervention. Understanding its impact on cancer hallmarks provides valuable insights into the potential of UA in developing targeted and multifaceted cancer therapies. This article explores UA activity in the context of disrupting hallmarks in cancer cells of different origins based on recent articles that emphasize the molecular mechanisms of this activity.

Uniformly dispersed FeOOH nanoparticles supported on alumina-carbon nanosheets for Cr(VI) removal

The mesoporous alumina-carbon nanosheets supported FeOOH nanoparticles were prepared by a facile and cost-effective hydrothermal synthesis for Cr(VI) removal in the wastewater, based on the affinity and selectivity of FeOOH and the accelerated mass transfer of nanosheet structure. The prepared nanoparticles with a small size of 2–5 nm were uniformly dispersed over the alumina-carbon nanosheets, attributed to the metal interaction and mesoporous confinement. The acid property after the introduction of alumina induced a positive charge on the surface of the adsorbent, which could enhance the adsorption of negatively charged metal ions. The Cr(VI) removal efficiency with the Al/Fe ratios showed a similar volcano curve. When Al/Fe ratio was around 3.3 and pHpzc was about 7.1, the adsorbent exhibited the best Cr(VI) removal efficiency of 99.4 %, owing to a large specific surface area, and small nanoparticle size, combined with abundant moderate-strong acid content of 294.5 μmol NH3 g−1.The Langmuir model could describe the adsorption process well, and the kinetic data was consistent with Pseudo-second-order. The thermodynamics revealed that the reaction process was spontaneous and endothermic. The adsorbent maintained a high removal efficiency of more than 80 % after running for five cycles and kept over 95 % under ionic co-existence and natural water conditions. Therefore, this study provides a new insight into the rational construction of efficient adsorbents with low-cost Cr(VI) removal.

CHIMERA_NA: A Customizable Mutagenesis Tool for Structural Manipulations in Nucleic Acids and Their Complexes.

Studying the structure and dynamics of nucleic acids and their complexes is crucial for understanding fundamental biological processes and developing therapeutic interventions. However, the limited availability of experimentally characterized nucleic acid structures poses a challenge for exploring their properties comprehensively. To address this, we developed a customizable mutagenesis tool, CHIMERA_NA, to manipulate nucleic acid structures and their complexes. Utilizing the user-friendly CHIMERA_NA, researchers can perform mutations in nucleic acid structures, enabling the exploration of diverse structural configurations and dynamic behaviors. The tool offers the flexibility to generate all possible combinations of mutations or specific user-defined mutations based on research requirements. CHIMERA_NA leverages the capabilities of UCSF Chimera software, a widely used platform for molecular structure analysis, to facilitate the generation of mutations in nucleic acids. Our tool modifies the reference structure of nucleic acids or their complexes to generate initial coordinates of mutated structures/complexes within seconds for further computational exploration. This capability allows users to extend their investigations beyond structural repositories, enabling the study of DNA/RNA drug recognition, nucleic acid-protein interactions, and the intrinsic structural and dynamic properties of nucleic acids. By providing a user-friendly and customizable approach to nucleic acid mutagenesis, CHIMERA_NA contributes to advancing our understanding of nucleic acid biology and facilitating drug discovery efforts targeting nucleic acid-based mechanisms. CHIMERA_NA is freely available in the Supporting Information of this article.

Reposition: Focalizing β-Alanine Metabolism and the Anti-Inflammatory Effects of Its Metabolite Based on Multi-Omics Datasets.

The incorporation of multi-omics data methodologies facilitates the concurrent examination of proteins, metabolites, and genes associated with inflammation, thereby leveraging multi-dimensional biological data to achieve a comprehensive understanding of the complexities involved in the progression of inflammation. Inspired by ensemble learning principles, we implemented ID normalization preprocessing, categorical sampling homogenization, and pathway enrichment across each sample matrix derived from multi-omics datasets available in the literature, directing our focus on inflammation-related targets within lipopolysaccharide (LPS)-stimulated RAW264.7 cells towards β-alanine metabolism. Additionally, through the use of LPS-treated RAW264.7 cells, we tentatively validated the anti-inflammatory properties of the metabolite Ureidopropionic acid, originating from β-alanine metabolism, by evaluating cell viability, nitric oxide production levels, and mRNA expression of inflammatory biomarkers. In conclusion, our research represents the first instance of an integrated analysis of multi-omics datasets pertaining to LPS-stimulated RAW264.7 cells as documented in the literature, underscoring the pivotal role of β-alanine metabolism in cellular inflammation and successfully identifying Ureidopropionic acid as a novel anti-inflammatory compound. Moreover, the findings from database predictions and molecular docking studies indicated that the inflammatory-related pathways and proteins may serve as potential mechanistic targets for Ureidopropionic acid.

Influence of Heat Treatment and Lactic Acid Fermentation on the Physical and Chemical Properties of Pumpkin Juice.

Pumpkin is a highly nutritious plant, rich in valuable nutrients that benefit human health. Due to the high perishability of this fruit, the production of pumpkin juice is a practical way to use it effectively. Recently, fermented vegetable juices have been used as a dairy alternative due to their nutritional and potential probiotic properties. This study investigated the fermentation of pumpkin juice using different strains of lactic acid bacteria (LAB), with and without heat treatment. The effects of fermentation on microbial growth, pH, acidity, extract, sugars, carotenoids, polyphenols, and antioxidant properties were analyzed. The heat-treatment process did not greatly impact the dry matter content, pH, acidity, extract, or sugar content. However, it led to a reduction in carotenoid and polyphenol levels. During fermentation, there was a consistent decrease in pH and an increase in total acidity, with no noticeable differences between bacterial strains regarding their influence on these parameters. The study revealed that there were no distinctions between LAB strains in their effects on pH, acidity, and carotenoid content in fermented pumpkin juice. Nonetheless, both L. sakei and L. plantarum proved to be effective in the fermentation process, with L. sakei demonstrating greater adaptability. The expected pH, acidity, and sugar content changes were consistently observed throughout the fermentation process. Overall, results confirm the efficacy of the used Lactobacillus strains in fermenting pumpkin juice and highlight the potential impact of heat treatment on the nutritional composition of the juice. The purpose of thermal processing of pumpkin juice, which is conducted with lactic acid fermentation, is crucial for the food industry. It extends the product's shelf life, improves its nutritional and taste profiles, and guarantees its microbiological safety.

Dry Eye Para-Inflammation Management: Preclinical and Clinical Evidence on a Novel 0.2% Hyaluronic Acid-Based Tear Substitute with 0.001% Hydrocortisone Sodium Phosphate.

Purpose: An innovative eyedrop formulation based on a combination of 0.2% hyaluronic acid and 0.001% hydrocortisone sodium phosphate (Idroflog®, Alfa Intes, Italy; HAC eyedrops) was granted a European Patent in 2016 and has been available on the market since 2019 in Europe and in other countries around the world. HAC eyedrops aim to synergize the moisturizing effects of hyaluronic acid with the mild anti-inflammatory properties of low-dose hydrocortisone, offering a more effective and safer alternative for treating dry eye disease (DED), targeting both tear film instability and dysfunctional para-inflammation. The activity of HAC eyedrops has been explored in different post-marketing clinical trials, in addition to preclinical studies. In this narrative review, we explored the available evidence on the use of HAC eyedrops for the management of para-inflammation in DED patients to provide a comprehensive overview of efficacy and safety data related to the use of this medical device in routine clinical practice. Methods: A literature search for preclinical and clinical data involving treatment with HAC eyedrops was conducted using PubMed/MEDLINE, considering only original research articles published in English, without time restrictions. Results: One preclinical and four clinical papers were retrieved. Preclinical evidence suggests that 0.001% hydrocortisone is able to control the expression of inflammatory markers, and this, together with the hydrating and lubricating properties of hyaluronic acid, leads to improvements in DED clinical signs, such as tear volume and the stability of the tear film. The results of clinical trials demonstrate that HAC eyedrops are able to improve the signs and symptoms of DED and that 0.001% low-dosage hydrocortisone can be helpful in preventing the progression to chronic stages of DED. Conclusions: HAC eyedrops represent a promising therapeutic strategy for the management of dysfunctional para-inflammation and offer a valuable addition to the armamentarium of treatments for DED.

Eco‐friendly approaches for synthesis of indolyl 1H‐pyrroles using rice‐husk‐derived carbonaceous sulfonation as the green catalyst

AbstractBACKGROUNDAmorphous carbon‐bearing sulfonic acid groups (AC–SO3H) are a kind of solid acid that exhibits high acidity and belongs to the new generation of solid acids. The presence of acidic functional groups, including carboxylic acid, phenolic and sulfonic acid groups, allows for several key activities such as strong Brønsted acid properties, high surface area, stability, reusability and recyclability.RESULTSIn this work, we synthesized indolyl 1H‐pyrroles from indoles, phenylglyoxal monohydrate, 1,3‐diketones and ammonium acetate using rice‐husk‐derived carbonaceous sulfonation (AC–SO3H) as a catalyst. We explored the impact of catalyst quantity, reaction time, solvent, mineral acid and temperature in order to determine the optimal reaction conditions. Additionally, indolyl 1H‐pyrrole derivatives were also synthesized based on the optimal conditions that were completely investigated, and the structure of these synthetic compounds was characterized by 1H‐ and 13C‐nuclear magnetic resonance.CONCLUSIONThe yield of indolyl 1H‐pyrroles was up to 84% in 6 h at 100 °C with the activity of 30 mg AC–SO3H. Besides, based on the optimal conditions, 21 indolyl 1H‐pyrrole derivatives were formed with the high‐yield and green method. The catalyst could be reused multiple times without a significant decrease in catalytic performance. According to the findings from the experiments, a potential mechanism that included a radical process has been suggested. This eco‐friendly approach provided a straightforward and efficient method to produce a variety of indole–pyrrole conjugates in a single step. © 2024 Society of Chemical Industry (SCI).