Sodium Azide Research Articles

Biological arsenite oxidation on iron-based adsorbents in groundwater filters

Iron-based adsorbents are commonly used to remove arsenic (As) from water for drinking water purposes. Here, we study the role of biological As(III) oxidation on iron-based adsorbents in filters and its effect on overall As uptake. A lab-scale filter with iron oxide coated sand (IOCS), a commonly used adsorbent, was operated with water containing As(III) and As(V), while water samples were taken periodically over its height. As(III) oxidation initiated after approximately 10 days and increased to a first order rate constant of 0.09 s−1 after 57 days resulting in full oxidation of As(III) in <50 s. Consequently, the filter shifted from an As(III) to an As(V) adsorbing filter. Oxidation was not observed after inhibiting the microbial activity using sodium azide confirming its biogenic nature. This implies that As(III) oxidizing biomass can grow on iron-based adsorbents in water filters without requiring inoculation. As the experimental conditions were similar to full-scale As treatment plants, we believe that biological As(III) oxidation is widely overlooked in these systems. Occurrence of biological oxidation is, however, beneficial for removal, as at pH <8 the adsorption capacity for As(V) can be up to 10-fold higher than for As(III). With these new insights, arsenic treatment using iron-based adsorbents can be further optimized. We suggest a more robust new design with a biological active As(III) oxidizing top layer and an As(V) adsorbing bottom layer.

Unexplored catalytic potency of a magnetic CoFe2O4/Ni-BDC MOF composite for the one-pot sustainable synthesis of 5-substituted 1-H tetrazoles

Within the domain of materials science and engineering, significant progress has led to the emergence of innovative materials based on magnetic MOFs, positioning them as promising candidates in the field of catalysis. This research aims to elaborate on the development of a finely tailored magnetic MOF composite; Ni-BDC (Nickel benzene-1,4-dicarboxylate) microflakes which was synthesized through a straightforward in-situ solvothermal approach. Extensive investigations into the structural properties of the resultant hybrid composite were carried out using various characterization techniques encompassing X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FT-IR), field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), Brunauer-Emmett-Teller (BET) analysis, atomic absorption spectroscopy (AAS), energy-dispersive X-ray spectroscopy (EDX), thermogravimetric analysis (TGA) and vibrating sample magnetometry (VSM). The developed material demonstrated remarkable efficiency in expediting the synthesis of a diverse array of pharmaceutically active 5-substituted 1H-tetrazole derivatives through a multicomponent coupling reaction involving substituted aldehydes, malononitrile, and sodium azide as key components. A noteworthy feature of this approach is its adherence to environmentally friendly reaction conditions, thus making it superior in comparison to previously established methodologies. Furthermore, a plausible mechanistic pathway has been proposed to elucidate the impressive performance of the developed catalytic system in the targeted reaction. It is anticipated that the current research will not only contribute to the purposeful designing of advanced magnetic MOF-based architectures but will also play a pivotal role in promoting sustainable practices in industrial processes, addressing pressing environmental and economic concerns.

Investigation of the influence of pH and temperature on melanization and survival under oxidative stress in Cryptococcus neoformans.

Cryptococcus neoformans is an opportunistic pathogenic fungus that produces melanin during infection, an important virulence factor in Cryptococcal infections that enhances the ability of the fungus to resist immune defense. This fungus can synthesize melanin from a variety of substrates, including L-DOPA (L-3,4-dihydroxyphenylalanine). Since melanin protects the fungus from various stress factors such as oxidative, nitrosative, extreme heat and cold stress; we investigated the effects of environmental conditions on melanin production and survival. In this study, we investigated the effects of different pH values (5.6, 7.0 and 8.5) and temperatures (30°C and 37°C) on melanization and cell survival using a microtiter plate-based melanin production assay and an oxidative stress assay, respectively. In addition, the efficacy of compounds known to inhibit laccase involved in melanin synthesis, i.e., tunicamycin, β-mercaptoethanol, dithiothreitol, sodium azide and caspofungin on melanization was evaluated and their sensitivity to temperature and pH changes was measured. The results showed that melanin content correlated with pH and temperature changes and that pH 8.5 and 30°C, were best for melanin production. Besides that, melanin production protects the fungal cells from oxidative stress induced by hydrogen peroxide. Thus, changes in pH and temperature drastically alter melanin production in C. neoformans and it correlates with the fungal survival. Due to the limited antifungal repertoire and the development of resistance in cryptococcal infections, the investigation of environmental conditions in the regulation of melanization and survival of C. neoformans could be useful for future research and clinical phasing.

Induced genetic diversity through mutagenesis in wheat gene pool and significant use of SCoT markers to underpin key agronomic traits

BackgroundThis research explores the efficacy of mutagenesis, specifically using sodium azide (SA) and hydrazine hydrate (HZ) treatments, to introduce genetic diversity and enhance traits in three wheat (Triticum aestivum L.) genotypes. The experiment entails subjecting the seeds to different doses of SA and HZ and cultivating them in the field for two consecutive generations: M1 (first generation) and M2 (second generation). We then employed selective breeding techniques with Start Codon Targeted (SCoT) markers to select traits within the wheat gene pool. Also, the correlation between SCoT markers and specific agronomic traits provides insights into the genetic mechanisms underlying mutagenesis-induced changes in wheat.ResultsIn the study, eleven genotypes were derived from parent varieties Sids1, Sids12, and Giza 168, and eight mutant genotypes were selected from the M1 generation and further cultivated to establish the M2 generation. The results revealed that various morphological and agronomical characteristics, such as plant height, spikes per plant, spike length, spikelet per spike, grains per spikelet, and 100-grain weight, showed increases in different genotypes from M1 to M2. SCoT markers were employed to assess genetic diversity among the eleven genotypes. The bioinformatics analysis identified a correlation between SCoT markers and the transcription factors ABSCISIC ACID INSENSITIVE3 (ABI3) and VIVIPAROUS1 (VP1), crucial for plant development, growth, and stress adaptation. A comprehensive examination of genetic distance and the function identification of gene-associated SCoT markers may provide valuable insights into the mechanisms by which SA and HZ act as mutagens, enhancing wheat agronomic qualities.ConclusionsThis study demonstrates the effective use of SA and HZ treatments to induce gene diversity through mutagenesis in the wheat gene pool, resulting in the enhancement of agronomic traits, as revealed by SCoT markers. The significant improvements in morphological and agronomical characteristics highlight the potential of mutagenesis techniques for crop improvement. These findings offer valuable information for breeders to develop effective breeding programs to enhance wheat quality and resilience through increased genetic diversity.

Mitochondrial DNA mutations attenuate Bleomycin-induced dermal fibrosis by inhibiting differentiation into myofibroblasts

Post-mitotic, non-proliferative dermal fibroblasts have crucial functions in maintenance and restoration of tissue homeostasis. They are involved in essential processes such as wound healing, pigmentation and hair growth, but also tumor development and aging-associated diseases. These processes are energetically highly demanding and error prone when mitochondrial damage occurs. However, mitochondrial function in fibroblasts and the influence of mitochondrial dysfunction on fibroblast-specific demands are still unclear. To address these questions, we created a mouse model in which accelerated cell-specific mitochondrial DNA (mtDNA) damage accumulates. We crossed mice carrying a dominant-negative mutant of the mitochondrial replicative helicase Twinkle (RosaSTOP system) with mice that express fibroblast-specific Cre Recombinase (Collagen1A2 CreERT) which can be activated by Tamoxifen (TwinkleFIBRO). Thus, we are able to induce mtDNA deletions and duplications in specific cells, a process which resembles the physiological aging process in humans, where this damage accumulates in all tissues. Upon proliferation in vitro, Tamoxifen induced Twinkle fibroblasts deplete most of their mitochondrial DNA which, although not disturbing the stoichiometry of the respiratory chain complexes, leads to reduced ROS production and mitochondrial membrane potential as well as an anti-inflammatory and anti-fibrotic profile of the cells. In Sodium Azide treated wildtype fibroblasts, without a functioning respiratory chain, we observe the opposite, a rather pro-inflammatory and pro-fibrotic signature. Upon accumulation of mitochondrial DNA mutations in vivo the TwinkleFIBRO mice are protected from fibrosis development induced by intradermal Bleomycin injections. This is due to dampened differentiation of the dermal fibroblasts into α−smooth-muscle-actin positive myofibroblasts in TwinkleFIBRO mice. We thus provide evidence for striking differences of the impact that mtDNA mutations have in contrast to blunted mitochondrial function in dermal fibroblasts and skin homeostasis. These data contribute to improved understanding of mitochondrial function and dysfunction in skin and provide mechanistic insight into potential targets to treat skin fibrosis in the future.

Cu‐Catalyzed Synthesis of [1,2,3]triazolo[1,5‐c]quinazolin‐5(6H)‐one Derivatives via Sequential Reaction of Ethyl‐2‐(2‐oxoindolin‐3‐ylidene)acetate with Sodium Azide

AbstractHerein, we report a novel and efficient method for the synthesis of new class of 5‐oxo‐5,6‐dihydro‐[1,2,3]triazolo[1,5‐c]quinazoline derivatives by copper‐catalyzed reaction of α, β‐unsaturated keto/ester methyleneindolinone with sodium azide at room temperature via an azide‐alkene cyclization and ring expansion rearrangement. This method is applicable to a variety of α, β‐unsaturated keto/ester methyleneindolinone and displayed wide functional group tolerance.

A simple, safe method for preserving dissolved methane in freshwater samples using benzalkonium chloride

AbstractMethane (CH4) dissolved in water is readily consumed by CH4‐oxidizing bacteria, so the possibility of the dissolved CH4 concentration (dCH4) in sampled water changing before analysis is a concern. To determine the accurate in situ dCH4 level, mercury chloride (HgCl2) or sodium azide (NaN3) is traditionally used for sample preservation. However, these preservatives are very toxic and great care must be taken when adding them to samples. Benzalkonium chloride (BAC), a quaternary ammonium salt cationic surfactant, is a readily available disinfectant that is less harmful to the human body than HgCl2, NaN3, and other preservatives. In this study, we investigated the usefulness of BAC in preserving dCH4 in swamp water, which is a critical terrestrial source of CH4. The dCH4 in samples without BAC decreased immediately after sample collection, whereas the dCH4 in the samples with added BAC did not change significantly for at least 15 d. In addition, when BAC was added to 18 water samples with different water chemistries, the dCH4 did not change significantly from immediately after sampling to 1 week after sampling (average difference: 3%). Thus, in the water samples used in this study, BAC effectively preserved dCH4 in the samples for at least 1 week. Further testing of the effect of BAC on the preservation of dCH4 in different types of water samples worldwide will help to establish a more complete, simple, and safe method.

Mutagenic Azido Impurities in Drug Substances: A Perspective.

Contamination of drug products and substances containing impurities is a significant concern in the pharmaceutical industry because it may impact the quality and safety of medicinal products. Special attention is required when mutagenic impurities are present in pharmaceuticals, as they may pose a risk of carcinogenicity to humans. Therefore, controlling potential mutagenic impurities in active pharmaceutical ingredients to an acceptable safety limit is mandatory to ensure patient safety. As per the International Council for Harmonization (ICH) M7 (R2)3 Guideline, mutagenic impurities are those compounds or materials that induce point mutations. In 2018, the sartan class of drugs was recalled due to the presence of N-nitrosamine impurities, which are potential mutagens. In addition to the primary impurities being detected, this class of products, especially losartan, irbesartan and valsartan, have been identified as having organic azido contaminants, which are again highly reactive toward DNA, leading to an increased risk of cancer. These azido impurities form during the preparation of the tetrazole moiety via the reaction of a nitrile intermediate with sodium azide. Given that this is a newly raised issue in the pharmaceutical world, it should be noteworthy to review the related literature. Thus, this review article critically accounts for (i) the toxicity of azido impurities and the proposed mechanism of mutagenicity, (ii) the regulatory perspective, and (iii) the sources and control strategies used during the preparation of drug substances and (iv) future perspectives.

Diastereoselective Synthesis of the HIV Protease Inhibitor Darunavir and Related Derivatives via a Titanium Tetrachloride-Mediated Asymmetric Glycolate Aldol Addition Reaction.

Darunavir is a potent HIV protease inhibitor that has been established as an effective tool in the fight against the progression of HIV/AIDS in the global community. The successful application of this drug has spurred the development of derivatives wherein strategic regions (e.g., P1, P1', P2, and P2') of the darunavir framework have been structurally modified. An alternate route for the synthesis of darunavir and three related P1 and P1' derivatives has been developed. This synthetic pathway involves the use of a Crimmins titanium tetrachloride-mediated oxazolidine-2-thione-guided asymmetric glycolate aldol addition reaction. The resultant aldol adduct introduces the P1 fragment of darunavir via an aldehyde. Transamidation with a selected amine (isobutylamine or 2-ethyl-1-butylamine) to cleave the auxiliary yields an amide wherein the P1' component is introduced. From this stage, the amide is reduced to the corresponding β-amino alcohol and the substrate is then bis-nosylated to introduce the requisite p-nitrobenzenesulfonamide component and activate the secondary alcohol for nucleophilic substitution. Treatment with sodium azide yielded the desired azides, and the deprotection of the p-methoxyphenoxy group is achieved with the use of ceric ammonium nitrate. Finally, hydrogenation to reduce both the aniline and azide functionalities with concurrent acylation yields darunavir and its derivatives.

Quinoline-1,2,3-triazole hybrids: Design, synthesis, antimalarial and antimicrobial evaluation

A new library of Quinoline appended 1,2,3-triazole hybrids of biotic interest was synthesized using terminal alkynes containing quinoline moiety, benzyl amine based bromides, sodium azide via click chemistry protocol and were assessed for antimalarial and antimicrobial potential. All of the synthesized triazoles were characterized using different spectral techinques viz. FTIR, 1H NMR,13C NMR and HRMS. Antimalarial activity of the synthesized quinoline-triazole hybrids against the Plasmodium falciparum strain displayed modest to good results. The synthesized compounds also reflected good antimicrobial potential against four bacteria (Staphylococcus aureus, Bacillus subtilis, Klebsiella pneumoniae, Escherichia coli) and two fungi (Candida albicans, Aspergillus niger). Molecular docking studies and in-silico ADME (Absorption, Distribution, Metabolism and Elimination) analysis were also performed to check the binding and drug-likeliness of the synthesized compounds.

Metal‐Free C(sp2)−H Functionalization of Cyclopentene‐1,3‐dione: A Greener Approach for C−N and C−O Bond Formation using Sodium Azide

AbstractThis article proposes a milder approach for C(sp2=−H functionalization of 2,2‐disubstituted cyclopentene‐1,3‐dione via formal 1° amination utilizing water as a solvent. In addition, this approach also offers C(sp2)−O, C(sp2)−I bond formation for the first time using sodium azide. The said highly scalable transformation does not require any prefunctionalization of the starting material. Moreover, this methodology is metal free, requires no ligand and all these reactions are carried out in an open‐air atmosphere with broad substrate scope. We have also explored a novel BF3.OEt2 mediated dehalogenation using mild reaction conditions.

Manganese (II) Chloride Tetrahydrate as an Efficient Catalyst for the Preparation of 5-Aryl-1H-tetrazoles via [3 + 2] Cycloaddition of Sodium Azide and Nitriles

Manganese (II) Chloride Tetrahydrate as an Efficient Catalyst for the Preparation of 5-Aryl-1H-tetrazoles via [3 + 2] Cycloaddition of Sodium Azide and Nitriles

Investigation on promising progenies of Dragon fruit (&lt;i&gt;Hylocereus &lt;/i&gt;spp.)

Dragon fruit (Hylocereus spp.) is an exotic vine cactus, rich in vitamin C and antioxidants, commonly known as ‘pitaya’ is a weather resilient crop. In order to develop superior varieties, a large number of progenies obtained from open pollinated seedling of cvs. Hiryur red, Vietnam pink and Vietnam red were raised and evaluated. To broaden the genetic base with desired traits, seeds of Hirehalli red and Hirehalli white were irradiated with gamma rays (500, 600 and 700 Gy), EMS (2.25, 2.5 and 2.75%) and sodium azide (0.04, 0.05 and 0.06%) and evaluated for horticultural traits. Three elite progenies such as CHESH-D1, CHESH-D2, and CHESH-D3 were obtained from open pollinated seedlings of cvs. Hiryur red, Vietnam red and Vietnam pink, respectively, and one EMS (2.5%) treated mutant i.e. CHESH-DE were selected based on their morphological and yield traits. The selection CHESH-D1 performed superior with highest fruit weight (507.71 g) and yield (39.50 kg/ pole) compared to CHESH-D2 and CHESH-D3. The biochemical characters namely, TSS (15.35 oB), total sugars (5.95 g), reducing sugars (4.91 g) and betalains (21.2 mg BCE) were recorded highest in CHESH-D2, and one EMS (2.5%) treated mutant from cv. Hirehalli red showed better adaptability and dwarfness. These elite progenies are at final stage of performance assessment to be released as variety in India.

Investigation on promising progenies of Dragon fruit (&lt;i&gt;Hylocereus &lt;/i&gt;spp.)

Dragon fruit (Hylocereus spp.) is an exotic vine cactus, rich in vitamin C and antioxidants, commonly known as ‘pitaya’ is a weather resilient crop. In order to develop superior varieties, a large number of progenies obtained from open pollinated seedling of cvs. Hiryur red, Vietnam pink and Vietnam red were raised and evaluated. To broaden the genetic base with desired traits, seeds of Hirehalli red and Hirehalli white were irradiated with gamma rays (500, 600 and 700 Gy), EMS (2.25, 2.5 and 2.75%) and sodium azide (0.04, 0.05 and 0.06%) and evaluated for horticultural traits. Three elite progenies such as CHESH-D1, CHESH-D2, and CHESH-D3 were obtained from open pollinated seedlings of cvs. Hiryur red, Vietnam red and Vietnam pink, respectively, and one EMS (2.5%) treated mutant i.e. CHESH-DE were selected based on their morphological and yield traits. The selection CHESH-D1 performed superior with highest fruit weight (507.71 g) and yield (39.50 kg/ pole) compared to CHESH-D2 and CHESH-D3. The biochemical characters namely, TSS (15.35 oB), total sugars (5.95 g), reducing sugars (4.91 g) and betalains (21.2 mg BCE) were recorded highest in CHESH-D2, and one EMS (2.5%) treated mutant from cv. Hirehalli red showed better adaptability and dwarfness. These elite progenies are at final stage of performance assessment to be released as variety in India.

Synthesis and antibacterial screening of some new 1'2'3 -triazole derivatives from dapsone

In our relentless pursuit of developing innovative antibacterial derivatives, we have successfully generated and evaluated a novel series of 1,2,3-triazole derivatives derived from azo dapsone. The synthesis process commenced with the fusion of the dapsone core with the triazole framework, establishing a solid foundation for our synthetic endeavors. Subsequently, the azo dapsone nucleus underwent functionalization using sodium azide, resulting in the creation of an azide derivative (B). To synthesize the desired end 1,2,3-triazoles, a click reaction was employed, combining the azide compound with triple bond derivatives. The structures of all the synthesized compounds were meticulously characterized through the utilization of advanced techniques such as Nuclear Magnetic Resonance (NMR) and Infrared (IR) spectroscopy. Following the successful synthesis and characterization, our focus shifted to evaluating the in vitro antibacterial activity of these compounds against two significant bacterial strains: the gram-positive bacterium Staphylococcus aureus and the gram-negative bacterium Escherichia coli. Among the compounds synthesized, one compound in particular, designated as (H2), exhibited exceptional potency against Staphylococcus aureus with a minimal inhibitory concentration (MIC) of 25 μg/mL, surpassing the activity of all other prepared compounds. Similarly, compound (H1) displayed remarkable efficacy against Escherichia coli with an MIC of 22 μg/mL, outperforming the other end compounds. These findings demonstrate the tremendous potential of our synthetic approach in generating dapsone derivatives with enhanced antibacterial activity. Our research represents a significant step forward in the development of novel and potent antibacterial agents.

Enhancement drought tolerance of sugar beet (Beta vulgaris L.) in vitro by sodium azide

Enhancement drought tolerance of sugar beet (Beta vulgaris L.) in vitro by sodium azide

In vitro α-glucosidase, docking and density functional theory studies on novel azide metal complexes.

Aim: The goal of this study is to synthesize new metal complexes containing N-methyl-1-(pyridin-2-yl)methanimine and azide ligands as α-glucosidase inhibitors for Type 2 diabetes. Materials & methods: The target complexes (12-16) were synthesized by reacting N-methyl-1-(pyridin-2-yl)methanimine (L1) with sodium azide in the presence of corresponding metal salts. The investigation of target protein interactions, vibrational, electronic and nonlinear optical properties for these complexes was performed by molecular docking and density functional theorystudies. Results: Among these complexes, complex 13 (IC50=0.2802±0.62μM) containing Hg ion showed the highest α-glucosidase inhibitory property. On the other hand, significant results were detected for complexes containing Cu and Ag ions. Conclusion: Complex 13 may be an alternate anti-diabetic inhibitor according to in vitro/docking results.

Identification of Induced Chemical Mutants for Improving Yield and its Attributing Traits in Wheat (Triticum aestivum L.) against Changing Climate

Background: The enhancement of genetic traits in any crop relies on the existing variability within that particular crop. Through hybridization and traditional breeding methods, the variability within wheat crops has been nearly exhausted. Consequently, mutation breeding emerges as the sole viable and promising approach to introduce new variability for further improvements. Methods: An experiment was conducted during the Rabi seasons of 2020-21 (M1 generation) and 2021-22 (M2 generation) at the Crop Research Centre, Department of Genetics and Plant Breeding, ITM University Gwalior. The experiment assessed the impact of five different concentrations of Sodium Azide (0.02%, 0.03%, 0.04%, 0.05%, and 0.1%) and Hydroxyl Amine (0.2%, 0.3%, 0.4%, 0.5% and 0.6%), in addition to a control, on the wheat varieties MP-3382 and RVW-4106. It employed a randomized block design with three replications. Result: The findings revealed that Sodium Azide and Hydroxyl Amine, the most effective dosages were observed to be 0.1per cent and 0.4 per cent, respectively, in inducing genetic and phenotypic changes in seed quality parameters. Specifically, for the flag leaf area characteristic, the most effective concentrations were 0.03 per cent Sodium Azide and 0.4 percent Hydroxyl Amine. Plant height exhibited the greatest variability at 0.03 per cent Sodium Azide, 0.5 per cent Hydroxyl Amine and 0.1 percent Sodium Azide. A dosage of 0.5 per cent Hydroxyl Amine was found to be most effective in altering spike length. In terms of days to 50 per cent flowering, 0.05 per cent Sodium Azide was identified as the most effective dosage. From the study of traits in both the M1 and M2 generations, 12 mutants were confirmed, with seven validated for variety MP-3382 and five for variety RVW-4106.

Gamma rays and sodium azide induced variations in bio-physiological and agronomical traits in linseed (Linum usitatissimum L.)

Linseed is a valuable oilseed crop with huge therapeutic importance due to its high content of omega-3 fatty acids in the form of Alpha-linolenic acid (ALA). It is a self-pollinated crop with a low-yielding potential that restricts its improvement endeavors. To overcome low-yielding potential, individual and combination treatments of gamma rays and sodium azide were employed in widely grown linseed varieties. The results revealed a dose-dependent decline in seed germination, seedling height, pollen fertility, chlorophyll, and carotenoid contents and a dose-independent decline in carbonic anhydrase activity. Bio-physiological parameters decreased substantially in combination treatments compared to individual treatments of gamma rays and sodium azide. In contrast, lower doses of gamma rays, sodium azide, and their combinations effectively increased mean values of yield and yield-attributing traits in a few putative mutants. Such putative mutants represent a valuable genetic resource that could be used in future breeding programs for the genetic improvement of linseed and related medicinal plants.

A new nickel-based δ-isomer Anderson-type polyoxometalates: Synthesis, crystal structure and catalytic activity in 1,2,3-triazoles production

In this study, we present a novel organic hybrid Ni-based δ-isomer of Anderson-type polyoxometalates (POMs), namely, δ-[C6H12Mo6N2NiO24]4− (1), as an efficient catalyst for the cycloaddition reaction between alkynes, halides, and sodium azide. Synthesis of the catalyst was performed using a facile one-pot method followed by characterization using single crystal, powder XRD, SEM, and FT-IR techniques. After optimizing reaction conditions for a model reaction (T = 80 °C, time = 6 h, and solvent = 2 mL H2O), the catalytic activity of this compound was examined for the preparation of diversely substituted 1,2,3-triazoles under ambient atmospheric and additive-free conditions, achieving moderate to good yields. Catalyst 1 could reuse up to four sequential cycles without significant loss in its catalytic activity. Additionally, the true heterogeneity of the catalyst was determined by the hot-filtration test.