HCl In Ethanol Research Articles

Regeneration of perfluorooctane sulfonic acid (PFOS) loaded granular activated carbon using organic/inorganic mixed solutions

Public concern about poly- and perfluoroalkyl substances (PFAS) in the environment has been raised due to their potential toxicity and environmental endurance. Adsorption using granular activated carbon (GAC) is a widespread strategy to remove PFAS. Herein, regeneration of PFAS-saturated GAC was studied and organic/inorganic mixed solutions were used to regenerate exhausted GAC. Optimization experiments revealed that a regenerant solution consisting of 0.1 mol/L HCl in ethanol with a 30-min residence time effectively regenerated PFAS-saturated GAC. The results showed that even after the fifth usage cycle, the proposed regeneration method can efficiently regenerate the PFAS-saturated GAC. Identification of the regeneration mechanism indicated that the regeneration process can be attributed to physical displacement and solubilization of PFAS from exhausted GAC. Additionally, BET analysis of PFAS-saturated and regenerated GACs revealed an increase in total pore volume and BET surface area in regenerated GACs, demonstrating the suggested method’s regeneration capabilities.

N-N(+) Bond-Forming Intramolecular Cyclization of O-Tosyloxy β-Aminopropioamidoximes and Ion Exchange Reaction for the Synthesis of 2-Aminospiropyrazolilammonium Chlorides and Hexafluorophosphates.

Our research area is related to the spiropyrazolinium-containingcompounds, which are insufficiently studied compared with pyrazoline-containing compounds. Nitrogen-containing azoniaspiromolecules have also been well studied. In drug design and other areas, they are a priori important structures, since rigid spirocyclic scaffolds with the reduced conformational entropy are able to organize a closely spaced area. Azoniaspirostructures are currently of wide practical interest as ionic liquids, current sources (membranes), structure-directing agents in organocatalysis, and in the synthesis of ordered ceramics. Our goal was the synthesis of 2-aminospiropyrazolilammonium chlorides and hexafluorophosphates. Our methodology is based on the tosylation of β-aminopropioamidoximes with six-membered N-heterocycles (piperidine, morpholine, thiomorpholine, and phenylpiperazine) at the β-position. 2-Aminospiropyrazolilammonium chlorides and hexafluorophosphates were obtained by the reaction of double ion substitution in the reaction of toluenesulfonates of 2-aminospiropyrazolinium compounds with an ethereal solution of HCl in ethanol and with ammonium hexafluorophosphate in ethanol in quantitative yields of 55-97%. The physicochemical characteristics of the synthesized compounds and their IR and NMR spectra are presented. The obtained salts were additionally characterized by the single-crystal XRD analysis. The presence of both axial and equatorial conformations of spirocations in solids was confirmed. 2-Aminospiropyrazolilammonium chlorides and hexafluorophosphates have weak in vitro antimicrobial activity on Gram-positive and Gram-negative bacterial lines.

β-Cyclodextrin network crosslinked by novel phosphonium-based tetrakiscarboxylic acid derived from PH3 tail gas: Synthesis and application for rapid removal of organic dyes from wastewater

Organic dyes, such as methyl orange (MO), Congo red (CR), crystal violet (CV) and methylene blue (MB), are common organic pollutants existing in wastewater. Therefore, the exploration of bio-based adsorbents for the efficient removal of organic dyes from wastewater has gained many attentions. Here, we report a PCl3-free synthetic method for the synthesis of phosphonium-containing polymers, in which the prepared tetrakis(2-carboxyethyl) phosphonium chloride-crosslinked β-cyclodextrin (TCPC-β-CD) polymers were applied to the removal of dyes from water. The effects of contact time, pH (1−11), and dye concentration were investigated. The selected dye molecules could be captured by the host-gest inclusion of β-CD cavities, and the phosphonium and carboxyl groups in the polymer structure would respectively facilitate the removal of cationic dyes (MB and CV) and anionic dyes (MO and CR) via electrostatic interactions. In a mono-component system, over 99 % of MB could be removed from water within the first 10 min. Based on the Langmuir model, the calculated maximum adsorption capacities of MO, CR, MB, and CV were 180.43, 426.34, 306.57, and 470.11 mg/g (or 0.55, 0.61, 0.96 and 1.15 mmol/g), respectively. Additionally, TCPC-β-CD was easily regenerated using 1 % HCl in ethanol, and the regenerative adsorbent still showed high removal capacities for MO, CR, and MB even after seven treatment cycles.

Environmentally benign, ultrasonication assisted, sustainable valorization for commercially important nutraceutical-Daucosterol from the heartwood of invasive Prosopis juliflora (Sw.) DC

Steroidal saponins are amphiphilic glycosidic chemical constructs, which possess diverse biological activities, that are attributable to the structural variations in the aglycone part and in the carbohydrate part. Daucosterol, a steroidal saponin, is a nutraceutical possessing various pleiotropic effects such as food preservative, immunomodulatory, anticancer and hypoglycemic effects. Non-conventional extraction methods have gained more importance as they provide target specific isolation, and thus, an eco-friendly sustainable process, optimized using Response surface methodology can be a viable proposition. P. juliflora, is an invasive plant, is seen as a major threat to agricultural lands, and is known to be a rich source for these saponins. Here we have reported a greener valorization procedure for Daucosterol from the heartwood of the invasive weed P. juliflora, various factors such as solvent, Solid-solvent ratio, extraction time, temperature, as well as aided valorization methods with microwave and ultrasonication were tested. Based on ‘one variable at a time’ experiments, which could influence the extraction process, an ultrasound-assisted valorization for daucosterol was developed. Response surface methodology was designed using a Box-Behnken method. Acetonic precipitation of Daucosterol yielded 8.02 mg/g of PJ, with the optimized conditions being 49.5 °C temperature, 14.6% solid loading and 0.76 M HCl in ethanol (v/v). It is also found that solvent had a greater influence on the extraction process. In order to understand the effect of acid treatment on the material, the cell wall constituents were quantified, and an acid-ethanol treatment method, improved the cell wall degradation and thereby increased the extraction efficiency of the nutraceutical, as evidenced by SEM images.

Simultaneous extraction of proteins and carbohydrates, including phenolics, antioxidants, and macamide B from Peruvian maca (Lepidium meyenii Walp.)

Maca (Lepidium meyenii Walp.) has been used for nutritional and traditional purposes, owing to its chemical composition and the presence of bioactive compounds. This study aimed to develop and optimize a maceration-based method for the simultaneous extraction of total phenolic compounds (TPCs), total flavonoids (TFs), radical-scavenging activity (RSA), soluble proteins (SPs), total sugars (TSs), reducing sugars (RSs), and macamide B from maca using 95% ethanol and acidified ethanol. The effects of extraction parameters, including temperature, solvent-to-solid ratio, time, and acid concentration, on the extraction yield of TPCs, TFs, RSA, SPs, TSs, RSs, and macamide B were investigated. Optimal extraction was achieved at 40-60°C for 5-7.5 h with the solvent-to-solid ratio of 100:10. The addition of hydrochloric acid (HCl) to ethanol significantly improved the extraction yield, and maximum extraction was achieved using 1 N HCl in ethanol. The RSA of the ethanolic extracts showed a significant linear correlation (p<0.001) with total extraction yield, TPCs, SPs, and TSs. These results imply that polyphenolic compounds, SPs/peptides, and polysaccharides are important determinants for the antioxidant function of maca. The optimized condition may be employed in nutraceutical industries to extract bioactive compounds from maca.

Synthesis of new derivatives of 1,3,4-thiadiazole and 1,3,4-oxadiazole on cyclic imides and studying their antioxidant

The research resulted in the production of new thiadiazole derivatives and oxadiazole derivatives via the reaction of cyclic imides with chloro acetyl chloride at heat condition to give N-acetyl chloro cyclic imides (1,2). Then react these compounds (1,2) with hydrazine hydrate to give N-(aceto hydrazide) cyclic imides (3,4). Then, compounds (3,4) go into three routes: route one was reacting with CS2 in the presence of (KOH) in ethanol at (24 hrs.) to give (N-[(2-thio-1,3,4-thiadiazolo-5-yl) methylene] cyclic imides) (5,6). Route two was reacting using various aromatic carboxylic acids in the presence of (POCl3) to give (N- [{2-(subs. benzene)-1,3,4-oxadiazolo-5-yl. methylene] cyclic imides) (7-14). Route three was reacting with ammonium thiocyanate in the presence of HCl in ethanol for (5 hrs.), followed cyclization in the presence of concentration (H2SO4) to give (N-[(2-amino-1,3,4-thiadiazolo-5-yl) methylene] cyclic imides) (15,16). Prepared compounds have been characterized by FTIR, and some of them by 1H-NMR, melting point, and were studied the effects of the preparing compounds on antioxidant.

Conformational Polymorphism in Safinamide Acid Hydrochloride (Z′ = 3 and Z′ = 1) and Observation of a Temperature-Dependent Reversible Single-Crystal to Single-Crystal Phase Transformation of High-Z′ form (Z′ = 3 ↔ Z′ = 2 via an Intermediate Z′ = 4)

Two concomitant polymorphs of safinamide acid hydrochloride were obtained in an attempt to prepare the O-protonated amide salt of safinamide from ethanolic HCl solution. Polymorph I crystallized in...

Separation of Scandium from Hydrochloric Acid-Ethanol Leachate of Bauxite Residue by a Supported Ionic Liquid Phase.

Solvometallurgy is a new branch of extractive metallurgy in which green organic solvents are used instead of aqueous solutions to improve selectivity in separation processes. In the present study, nonaqueous leaching of a Greek bauxite residue (BR) was performed and scandium was separated from other elements in the leachate by column chromatography. At first, the selectivity of sorbents for scandium(III) over iron(III) was tested in batch mode using various organic solvents. The following three sorbents were tested: (1) a carboxylic acid-functionalized supported ionic liquid phase (SILP), (2) silica (SiO2), and (3) silica functionalized with ethylenediaminetetraacetic acid (SiO2–TMS–EDTA). The best separation of scandium and iron was achieved from ethanolic solution by the SILP. The BR was then leached with 0.7 mol L–1 HCl in ethanol or in water. The leaching efficiency of scandium with both lixiviants was similar. However, much less sodium was leached, and silica remained in solution when leaching was performed with the ethanolic lixiviant. By using ethanol as opposed to water, the serious drawback of silica gel formation that is taking place in the aqueous leachate of BR was circumvented. The sorption preference of the SILP for metal ions in the ethanolic leachate was partly reversed compared to the aqueous leachate. Iron was separated from other metals of the ethanolic BR leachate by a simple elution with ethanol. The formation of the anionic tetrachloroferrate(III) complex, [FeCl4]−, enabled the selective elution. This complex was not observed in the aqueous leachate of BR. Scandium was separated from the vast majority of other components of the BR by elution with 0.1 mol L–1 H3PO4.

Green synthesis of new hippuric hydrazones

Hippuric hydrazones 4–8 were prepared starting from treating the corresponding acid with ethanolic HCl forming the corresponding ester 2. The formed ester was then converted to ethyl hippurate 3 by treating the ester with hydrazine hydrate. The formed ethyl hippurate was then irradiated with various substituted aromatic aldehydes under solvent-free conditions forming new series of hippuric hydrazones 4–8. Developing clean synthetic route for synthesizing hippuric hydrazones is the main point of this work which is environmentally and economically desirable. The synthesized compounds were confirmed by spectral NMR, mass, IR and CHN analysis data.

New Products Generated from the Transformations of Ferulic Acid Dilactone.

Various ferulic acid (FA) dimers occurring in plant cell walls, such as 8-5-, 8-O-4-, 5-5-, and 8-8-coupled dimers, are effective antioxidants and potential antimicrobials. It is necessary to access these diferulates as reference compounds to validate those isolated from plants. 3,6-bis(4-hydroxy-3-methoxyphenyl)-tetrahydrofuro-[3,4-c]furan-1,4-dione, a 8-8-coupled FA dilactone generated from ferulic acid via radical coupling, has been used to synthesize 8-8-coupled FA dimers although few reports investigated the distribution of products and mechanisms involved in the transformation of FA dilactone. In this work, the FA dilactone, obtained from FA by a peroxidase-catalyzed radical coupling, was reacted under various base/acid conditions. Effects of reaction conditions and workup procedures on the distribution of products were investigated by GC-MS. The isolated products from such treatments of FA dilactone were characterized by NMR. New derivatives of FA dimer including 2-(4-hydroxy-3-methoxybenzylidene)-3-(hydroxyl-(4-hydroxy-3-methoxyphenyl)methyl)succinic acid and 2-(bis(4-hydroxy-3-methoxyphenyl)-methyl)-succinic acid were produced from NaOH treatment. Another novel 8-8-coupled cyclic FA dimer, diethyl 6-hydroxy-1-(4-hydroxy-3-methoxyphenyl)-7-methoxy-1,2-dihydronaphthalene-2,3-dicarboxylate was identified in products from FA dilactone treated by dry HCl in absolute ethanol. Mechanisms involved in such transformations were proposed.

Synthesis of a New Series of Nitrogen/Sulfur Heterocycles by Linking Four Rings: Indole; 1,2,4-Triazole; Pyridazine; and Quinoxaline.

A new series of nitrogen and sulfur heterocyclic systems were efficiently synthesized by linking the following four rings: indole; 1,2,4-triazole; pyridazine; and quinoxaline hybrids. The strength of the acid that catalyzes the condensation of 4-amino-5-(1H-indol-2-yl)-2,4-dihydro-3H-1,2,4-triazole-3-thione 1 with aromatic aldehydes controlled the final product. Reflux in glacial acetic acid yielded Schiff bases 2–6, whereas concentrated HCl in ethanol resulted in a cyclization product at C-3 of the indole ring to create indolo-triazolo-pyridazinethiones 7–16. This fascinating cyclization approach was applicable with a wide range of aromatic aldehydes to create the target cyclized compounds in excellent yield. Additionally, the coupling of the new indolo-triazolo-pyridazinethiones 7–13 with 2,3-bis(bromomethyl)quinoxaline, as a linker in acetone and K2CO3, yielded 2,3-bis((5,6-dihydro-14H-indolo[2,3-d]-6-aryl-[1,2,4-triazolo][4,3-b]pyridazin-3 ylsulfanyl)methyl)quinoxalines 19–25 in a high yield. The formation of this new class of heterocyclic compounds in high yields warrants their use for further research. The new compounds were characterized using nuclear magnetic resonance (NMR) and mass spectral analysis. Compound 6 was further confirmed by the single crystal X-ray diffraction technique.

Development of C-Arylcalix[4]resorcinarenes and C-Arylcalix[4]pyrogallolarenes as Antioxidant and UV-B Protector

Indonesia is rich with essential oils such as anise and clove leave oils. In respect to explore the potential utilization of these resources, it has been conducted the transformation of p-hydroxybenzaldehyde and vanillin (4-hydroxy-3-methoxy benzaldehyde) respectively derived from anise oil and clove leaves oil to a series of C-arylcalix[4]resorcinarenes and C-arylcalix[4]pyrogallolarene macrocycles. Treatment of these aldehydes with resorcinol in the presence of HCl in absolute ethanol at reflux for 8 h afforded C-4-hydroxyphenylcalix[4]resorcinarene (3a) and C-4-hydroxy-3-methoxy phenyl-calix[4]resorcinarene (3b) in good yields. When the aldehydes were treated with pyrogallol under the similar condition, the products were C-4-hydroxyphenyl calix[4]pyrogallolarene (3c) and C-4-hydroxy-3-methoxyphenylcalix[4]pyrogallolarene (3d) which were also obtained in excellent yields. Treatment of these calix[4]resorcinarenes and calix[4]pyrogallolarenes with cinnamoyl chloride and benzoyl chloride in pyridine afforded the corresponding cinnamate esters and benzoate esters in high yields. The resulted C-arylcalix-[4]resorcinarenes and C-arylcalix[4]pyrogallol arenes were subjected to antioxidant activity test using DPPH method and showed strong activity with IC50 values of 15–80 μg/mL. In terms of the synthesized calix cinnamates, the compounds showed UV-B absorption with SPF values of 15–30 at a concentration of 25 ppm which demonstrate their potential to be applied as a UV-B protector. Furthermore, these compounds were also tested for their photostability on the UV-B region and the results showed that the compounds were still unstable under irradiation for 30 min.

Efficient One-Pot, Two-Component Modular Synthesis of 3,5-Disubstituted Pyrazoles.

The pyrazole scaffold is one of the most prevalent and important tool in medicinal chemistry. Here, we report a method for preparing 3,5-diarylpyrazoles in good to excellent yield by reacting hydrazones of aryl aldehydes with substituted acetophenones in ethanol in the presence of dimethyl sulfoxide/cat. I2/cat. HCl. The reverse process, reacting hydrazones of substituted acetophenones with aryl aldehydes under the same conditions, also provides 3,5-diarylpyrazoles in good to excellent yields. Reaction of hydrazones of aldehydes with 2′-aryloxy ketones in the presence of cat. HCl in ethanol and the catalyst-free reaction of phenacyl bromides with hydrazones of aldehydes in ethanol also gave good to excellent yields of 3,5-diarylpyrazoles.

Acid Catalyzed One‐pot Three‐component Biginelli‐type Synthesis of Some New Symmetrical Bis 3,4‐dihydropyrimidin‐2(1H)‐ones/thiones

Biologically important 21 new symmetrical bis 3,4‐dihydropyrimidin‐2(1H)‐ones/thiones were synthesized by reacting 4,4′‐diaminodiphenyl ether/4,4′‐ethylenedianiline with tert‐butyl acetoacetate to produce diphenyl ether‐bridged bis β‐keto amide/diphenyl ethane‐bridged bis β‐keto amide then treated with urea or thiourea and an appropriate aldehyde with either a catalytic amount of p‐TSA·H2O or conc. HCl in ethanol afforded the title compounds.

Condensation reactions of indole with acetophenones affording mixtures of 3,3-(1-phenylethane-1,1-diyl)bis(1H-indoles) and 1,2,3,4-tetrahydro-3-(1H-indol-3-yl)-1-methyl-1,3-diphenylcyclopent[b]indoles

Condensation of indole 1a with eight acetophenones 8a–h in ethanolic HCl afforded the corresponding mixtures of condensation products: 3,3-(1-phenylethane-1,1-diyl)bis(1H-indoles) 11a–h (2:1 condensation of indole:acetophenone, –H2O) and diastereomers of substituted 1,2,3,4-tetrahydro-3-(1H-indol-3-yl)-1-methyl-1,3-diphenylcyclopent[b]indoles 12a–h and 13a–h (2:2 condensation of indole:acetophenone, –2H2O). Each mixture was analyzed by 1H NMR. The use of substituted electron-withdrawing acetophenones favored formation of 2:1 condensation products, whereas the use of substituted electron-donating acetophenones favored formation of 2:2 condensation products. Increased reaction temperature gave higher 2:2 condensation yields, but temperatures above 40 °C were unfavorable, giving complex, tarry mixtures.

Complexes of Ambidentate N,O-Donor Ligands with Rhenium(I) and -(V)

The reaction of the potentially bidentate ambidentate N,O-donor ligands 3-hydroxy-2-pyridinecarboxylic acid (Hhpc) and 3-hydroxy-2-(hydroxymethyl)pyridine (Hhhp) with trans-[ReOCl3(PPh3)2] led to the isolation of the products [ReOCl(hpc)2] (1) (from acetonitrile) and [ReOCl2(hhp)(PPh3)] (2) (from ethanol) respectively. In both complexes hpc and hhp are coordinated as bidentate N,O-donor chelates, rather than as O,O-donor ligands. From the reaction of [Re(CO)5Cl] and Hhhp·HCl in ethanol the neutral complex fac-[Re(CO)3Cl(Hhhp)] (3) was obtained, with N,O-coordination of Hhhp. Complex 1 crystallizes in the monoclinic space group P21/n with a = 6.8782(3), b = 20.0647(8), c = 10.8692(4) A, β = 107.545(1)°, and Z = 4. Complex 2 crystallizes in the triclinic space group P-1 with a = 7.3523(4), b = 8.1047(5), c = 19.591(1) A, α = 91.133(2)°, β = 93.656(2)°, γ = 93.074(2)° and Z = 2. Complex 3 has monoclinic P21/c symmetry with the cell parameters a = 10.6452(5), b = 11.1372(5), c = 9.7229(5) A, β = 106.107(2)°, and Z = 4.

Synthesis of 2-(9H-carbazol-1-yl)anilines from 2,3′-biindolyl and ketones

Twenty-nine examples of 2-(9H-carbazol-1-yl)anilines were obtained in yields from 27 to 95% by refluxing 2,3′-biindolyl (1 equiv.) and ketones (1 equiv.) in ethanolic HCl. Alkyl, cyclic, and aryl ketones were found to be compatible with this method, however, aldehydes are not. Because the reaction proceeds by addition of the carbonyl C atom to the biindolyl 3-position, this method has high regioselectivity. One example is presented of bridging the two N atoms in the carbazolylaniline product with an acetaldehyde synthon to give a benzodiazepino[lm]carbazole. Also, one example is given of installing a dimethylamino group at the α-position of the starting ketone to give an indolo[3,2-c]carbazole.

One-Pot Synthesis of Novel Substituted Phenyl-1,5-dihydro-2Hbenzo[ 4,5]thiazolo[3,2-a]pyrimido[4,5-d]pyrimidine Derivatives as Potent Antimicrobial Agents

In this paper, we have reported the synthesis of novel substituted phenyl-1,5-dihydro-2H-benzo[4,5] thiazolo[3,2-a]pyrimido[4,5-d]pyrimidine derivatives (4a-m). The title compounds were synthesized by the reaction of substituted 2-aminobenzothiazole, barbituric/thiobarbituric acid and substituted benzaldehydes using 2-3 drops of HCl in ethanol. The synthesized compounds were evaluated for their antimicrobial efficiency against various microbial strains at different concentrations. Among the tested compounds, the compounds 4k and 4j were found to be more active against all the tested pathogens. Additionally, selected compounds were screened for in silico molecular docking studies.

Effects of dextrinization and octenylsuccinylation of high amylose starch on complex formation with ω-3 fatty acids (EPA/DHA)

High amylose maize starch (70% amylose) was dextrinized in an acid/alcohol solution (0.36% HCl in ethanol, 50 °C for 24 h), and the starch and its dextrin were octenylsuccinylated (DS 0.019) to be utilized as complex forming agents for ω-3 fatty acids (eicosapentaenoic acid and docosahexaenoic acid). A fish oil was used as the fatty acid sample and dispersion with starch and fish oil was stirred at 60 °C for 3 h and cooled at an ambient temperature for 3 h. The complex was isolated as the precipitates after centrifugation (25,000 × g, 25 °C for 30 min), and then the recovery of fatty acids in the complex and crystalline characteristics of the complex were examined. Dextrinization improved the efficiency of complex formation, increasing the recovery of fatty acids and decreasing the recovery of solid precipitates. Octenylsuccinylation, however, retarded the complex formation showing a decrease in fatty acid recovery. It was hypothesized that intermolecular complex between amylose and octenyl group in the substituents was formed during the reaction because the modified starch and dextrin without fatty acids showed a new endotherm (at around 100 °C) in their thermograms. Because of the possible competition between the substituents and fatty acids in complex formation, octenylsuccinylation hindered the complex formation between amylose and fatty acids. The fatty acid complex particles prepared with native starch or dextrin showed average particle size less than 400 nm with zeta potential below −40 mA, assuring the dispersion stability during an ambient storage.

Titrimetric determination of maleinimide and acrylate groups in organic compounds

A simple procedure is proposed for determining the concentration of maleimide and acrylate groups in organic compounds based on the addition of morpholine to the activated double bond by the Michael reaction, followed by the potentiometric titration of the reaction mixture with 1 M HCl in ethanol. The applicability of the method to N-substituted maleimides with aromatic, aliphatic, and oligomeric substituents, as well as to acrylates and acrylonitrile, is verified. It is demonstrated that maleimides and acrylates can be determined simultaneously.