Addition Of Hydroxylamine Hydrochloride Research Articles

Highly efficient removal of organic contaminants and hydroxylamine hydrochloride enhancement effect based on magnetic iron/nitrogen doped carbon nanolayer

Developing highly effective and environmental friendliness Fe-based catalysts have attracted increasing attention. Herein, novel nitrogen-doped carbon nanolayer with Fe0/Fe3C nano-particles (Fe@NCL-900) were innovatively fabricated by a simple solvent-free strategy, pyrolyzed the mixture of 4,6-dihydroxypyrimidine and ferric chloride hexahydrate under 900 ℃. In the presence of peroxymonosulface (PMS), Fe@NCL-900 could remove almost 100% Carbamazepine in 6 min with an amazing apparent first-order constant (kobs) as high as 0.733 min−1, about 72 and even 88 times higher than that of the commercial zero-valent iron and the traditional Fenton system, respectively, which was mainly ascribed to the synergistic effect of high graphite carbon and excellent reducing ability of Fe0. Moreover, high valent iron species (Fe (IV)) and four types of reactive oxygen species (ROS) including hydroxyl radical (•OH), sulfate radical (SO4•-), singlet oxygen (1O2), superoxide radical (O2•-) were detected to play a key role in Carbamazepine removal by electron paramagnetic resonance (EPR) and the radical quenching experiments. Interestingly, it was observed that the addition of hydroxylamine hydrochloride could effectively improve the production of more ROS and the first-order constant was enhanced by 7.6 times (5.593 min−1), completely different from the previous reports that hydroxylamine hydrochloride in high concentrations would inhibit the removal rate. Moreover, the magnetically separable catalyst possessed a wide pH range (2.0–10.0) and superior reusability. This study provides novel insights for manufacturing a promising Fe-based nitrogen-doped catalyst in practical wastewater treatment.

Enhanced effects of reducing agent on oxalate chelated Fe(II) catalyzed percarbonate system for benzene degradation

Abstract The addition of hydroxylamine hydrochloride (HAH), ascorbic acid (ASC), sodium ascorbate (SAS) to the OA-Fe(II)/SPC system could promote the generation of HO• by accelerating Fe(II)/Fe(III) recycles and H2O2 decomposition. The enhancement of HAH on HO• generation surpasses ASC and SAS in the OA-Fe(II)/SPC system. The generation of O2•− was also enhanced by HAH, ASC and SAS, and more significant promotion of O2•− generation was observed with ASC and SAS addition. More effective benzene removal was achieved in an OA-Fe(II)/SPC system with suitable HAH, ASC and SAS addition, compared to the parent system. Excessive HAH, ASC or SAS had a negative effect on benzene removal. Results of scavenger tests showed that HO• is indeed the dominant free radical for benzene removal in every system, but the addition of HAH, ASC and SAS increased the contribution of O2•− to benzene degradation. HAH, ASC and SAS enhanced OA-Fe(II)/SPC systems could be well utilized to acidic and neutral conditions, while HCO3−, high concentration of HA and alkaline conditions were not favorable to benzene removal. Moreover, the addition of HAH, ASC and SAS are conducive to benzene removal in actual groundwater, and HAH was the optimal reducing agent for the enhancement of the OA-Fe(II)/SPC system.

When hydrogen bond tailors molecular packing in non-anisometric molecules. The case study of N-alkyl 1,3-diphenyl-4,5-dihydro-1H-pyrazole-5-carboximidamides

ABSTRACT In this paper, we report the synthesis of novel liquid crystals (LCs) based on 5-membered pyrazoline heterocycle. The synthesis of pyrazoline derivative was carried out by [3 + 2] 1,3-dipolar cycloaddition reaction of benzaldehyde phenyl hydrazone (1) with acrylonitrile, mediated by chloramine-T as the oxidising agent, followed by addition of hydroxylamine hydrochloride, and subsequently alkylated with various alkyl chains to afforded the title compounds. The LCs properties were investigated using differential scanning calorimetry and polarising optical microscopy. For title compounds with longer alkyl chains, monotropic columnar hexagonal mesophase was characterised by XRD analysis. The mesophase-formation was driven by intermolecular hydrogen bonds despite their non-discoid molecular structure.

Degradation of Humic Acid by Ferrous Ion Activated Persulfate

The persulfate anions (S2O8 2™) can be activated by Fe2+ to produce sulfate radicals (·SO4 −) and hydroxyl radicals (·OH), which can oxidize organic compounds rapidly. Humic acid (HA) is widely found in nature and is the main limiting factor for high-concentration wastewater discharge. In this study, HA was treated by Fe2+/S2O8 2™ system, the effects of initial pH, concentrations of Fe2+, persulfate (PS), and HA on the removal efficiencies of HA and E3/E4 were discussed. Besides UV254 and UV280, we found that UV250, UV270, UV300, UV365, UV400, UV436 and UV465 can effectively quantified the concentrations of HA, providing more HA characterization methods. When the initial pH was 3.0, the concentrations of PS and Fe2+ were 100 mmol/L and 20 mmol/L, respectively, the removal efficiency of HA reached 72% after 5 minutes, indicating that PS/Fe2+ effectively degrade HA, and E3/E4 increased from 2.6 to 5.75, suggesting the molecular weight and aromaticity of HA decreased. The removal efficiencies of HA increased as the concentrations of Fe2+ and PS increased, while the removal efficiencies of HA decreased as the initial concentration of HA increased. The addition of hydroxylamine hydrochloride (HAH) in Fe2+/S2O8 2™ system, could effectively promoted the Fe3+/Fe2+ circulation and reduced the accumulation of Fe3+, and strengthened the removal efficiency of HA. The research results indicate that Fe2+/S2O8 2™ oxidation is a promising technique for the treatment of HA in wastewater.

N-doped carbon dots sensor for selective detection of hydroxylamine hydrochloride

The preparation of N-doped carbon dots (N-CDs) was facile and efficient by the hydrothermal method, using diethylenetriamine (DETA) and citric acid (CA) as nitrogen source and carbon source, respectively. The fluorescence of N-CDs was effectively quenched by Fe3+. Upon addition of hydroxylamine hydrochloride (HH) to N-CDs/Fe3+ complex dispersion, the fluorescence of N-CDs was significantly recovered. Therefore, we developed an “off-on” fluorescence assay for the detection of HH using N-CDs/Fe3+ as a fluorescence probe. The fluorescence intensity showed linearity with the added HH concentration ranging from 0 to 100 μM with the detection limit of 0.246 μM (S/N = 3). The proposed N-CDs sensing showed high selectivity and sensitivity to detection HH in aqueous solution.

Determination of Ultraviolet Absorbers and Light Stabilizers in Food Packaging Bags by Magnetic Solid Phase Extraction Followed by High-Performance Liquid Chromatography

A sensitive and effective extraction technique based on magnetic solid phase extraction (MSPE) was developed for separating and detecting trace amounts of ultraviolet (UV) absorbers and light stabilizers in plastic packaging prior to high-performance liquid chromatography (HPLC). The magnetic Fe3O4/Au composites were synthesized by chemical co-precipitation, and a HAuCl4 solution was added to the Fe3O4 NPs, followed by the addition of hydroxylamine hydrochloride as a reducing agent for Au shell formation. The main factors affecting the adsorbability of UV absorbers, such as the effects of pH of the sample solution, the amount of adsorbent, extraction time, and desorption conditions on the magnetic nanoparticles (MNPs), were investigated and optimized. The proposed method showed good linearity in the range from 0.75 to 100 μg/mL with good presenting regression coefficients (R 2) ≥0.9999. Low limits of detection (LODs) were achieved at 0.05, 0.14, and 0.04 μg mL−1 for 2-hydroxy-4-n-octoxy-benzophenone (UV-531), 2-tert-butyl-6-(5-chloro-2H-benzotriazol-2-yl)-4-methylphenol (UV-326), and 2-(2H-benzotriazol-2-yl)-4,6-di-tert-pentylphenol (UV-328), respectively. The mean recoveries were in the range from 88.06 to 100.29% at 2.5, 5, and 10 μg mL−1 spiked levels, and the relative standard deviations (RSDs) were in the range from 0.98 to 3.56%.

ChemInform Abstract: Pictet-Spengler Reactions in Aprotic Media. The Total Synthesis of (.+-.) Suaveoline.

Abstract The first total synthesis of the indole alkaloid (±)-suaveoline 1 (a macroline-related base and a member of the sarpagine/ajmaline class of alkaloids) was completed in a stereocontrolled fashion. The serial synthesis employed three intramolecular reactions, the Pictet-Spengler cyclization ( 11 → 20 ), the Dieckmann condensation ( 21 → 22 ) and the orthoester Claisen rearrangement ( 25 → 30 ), all of which occurred with high stereoselectivity. Construction of the unique 3,4,5-trisubstituted pyridine ring ( E ) of 1 was executed by addition of hydroxylamine hydrochloride to an ethanolic solution of the corresponding 1,5-daildehyde 36 which was followed by heating. The related base (±)-N b -methylsuaveoline 38 was prepared from 37 via catalytic devenzylation (Pd/C, H 2 ) in the presence of formic acid (78% yield).

Nitrogen containing additives in soda pulping of bagasse pith

AbstractUnbleached soda pulp was prepared from Egyptian bagasse pith by varying the alkali concentration and the time of heating at the boiling point of the liquor under atmospheric pressure. A linear relationship was observed between the dissolved pith and the dissolved lignin. Pulping with alkali concentration higher than 10% but not exceeding 16% was more effective, since more delignification took place with lower dissolved pith percentage. p‐ And m‐nitrobenzoic acids and also hydroxylamine hydrochloride had a slight or no effect on the yield of the pulps. The alkali solubility percentage of the pulps prepared in the presence of any of the additives was lower than the control pulp. The delignification was enhanced more on the addition of hydroxylamine hydrochloride than p‐nitrobenzoic acid, while m‐nitrobenzoic acid seemed to have no effect. The yield of the pulps thus prepared, as determined by weighing, showed lower values than those determined by a chemical method. The soda delignification rate was shown to be proportional to the amount of unremoved lignin and the concentration of alkali in the liquor. The delignification reaction was found to follow approximately first‐order kinetics.

Determination of chromium in low-alloy steels by atomic-absorption spectrophotometry

Iron causes severe depression of the signal in determination of chromium by atomic-absorption spectrophotometry in an air—acetylene flame. This effect can be eliminated by addition of hydroxylamine hydrochloride and use of a fuel-rich flame. Addition of iron to the standard solutions is not necessary for up to 300 ppm of iron in the test solution.