Formaldehyde In Aqueous Solution Research Articles

Water-soluble polymeric probe with tryptophan pendants for formaldehyde sensing

Formaldehyde (FA) is a grade-I carcinogen and the most reactive aldehyde in the carbonyl family, posing substantial health hazards. Herein, a water-soluble polymeric probe with side-chain tryptophan pendants is proposed that relies on an FA-induced Pictet-Spengler reaction for FA sensing in an aqueous medium. The polymeric probe shows cyan fluorescence in an aqueous medium after the interaction with FA due to the formation of a β-carboline derivative, confirmed by high-resolution mass spectrum analysis of the product from the model reaction between tryptophan methyl ester and FA. The copolymer’s sensitivity to FA in aqueous solutions at the nanomolar level is estimated using the fluorescence titration method, where ∼20-fold enhancement in fluorescence intensity is observed within 2 min when 200 µM FA is added to the aqueous solution of the copolymer. The probe can selectively detect FA using colorimetric and fluorometric methods with a detection limit as low as 25 nM. The FA-sensing mechanism is studied from the model reaction of tryptophan methyl ester (TME) with FA, and density functional theory (DFT).

Heterogeneous Oxidase-Type Catalysis for H2 Generation at Low Temperatures.

The long-term objective in the field of heterogeneous catalysis is to develop an enzyme-like catalytic pathway that can achieve exceptional catalytic performance even at low temperatures. Herein, we have demonstrated a heterogeneous oxidase-type catalysis on the ZnO-supported Ru clusters (Ru/ZnO) for efficient H2 generation from an aqueous solution of formaldehyde (HCHO) at low temperatures. Due to its unique reaction pathway, the Ru/ZnO catalysts exhibited a temperature-insensitive activity for H2 generation at the temperature of 15 to 45 °C. Remarkably, even at a low temperature of 5 °C, the Ru/ZnO catalysts still enabled an H2 generation rate of 13.8 mmol gcat-1 h-1 with a turnover frequency (TOF) of 1678 h-1. Additionally, instead of producing a CO2/CO molecule, the HCHO molecule underwent a transformation into formic acid and/or formate as the byproduct. This finding presents a novel class of heterogeneous catalysts to expand the potential application scenarios of liquid hydrogen storage and transportation systems.

Pyrrolic Nitrogen Boosted H2 Generation from an Aqueous Solution of HCHO at Room Temperature by Metal-Free Carbon Catalysts.

Hydrogen production from organic hydrides represents a promising strategy for the development of safe and sustainable technologies for H2 storage and transportation. Nonetheless, the majority of existing procedures rely on noble metal catalysts and emit greenhouse gases such as CO2/CO. Herein, we demonstrated an alternative N-doped carbon (CN) catalyst for highly efficient and robust H2 production from an aqueous solution of formaldehyde (HCHO). Importantly, this process generated formic acid as a valuable byproduct instead of CO2/CO, enabling a clean H2 generation process with 100% atom economy. Mechanism investigations revealed that the pyrrolic N in the CN catalysts played a critical role in promoting H2 generation via enhancing the transformation of O2 to generate •OO- free radicals. Consequently, the optimized CN catalysts achieved a remarkable H2 generation rate of 13.6 mmol g-1 h-1 at 30 °C. This finding is anticipated to facilitate the development of liquid H2 storage and its large-scale utilization.

Gamma-Ray-Induced Amino Acid Formation during Aqueous Alteration in Small Bodies: The Effects of Compositions of Starting Solutions.

Organic compounds, such as amino acids, are essential for the origin of life, and they may have been delivered to the prebiotic Earth from extra-terrestrial sources, such as carbonaceous chondrites. In the parent bodies of carbonaceous chondrites, the radioactive decays of short-lived radionuclides, such as 26Al, cause the melting of ice, and aqueous alteration occurs in the early stages of solar system formation. Many experimental studies have shown that complex organic matter, including amino acids and high-molecular-weight organic compounds, is produced by such hydrothermal processes. On the other hand, radiation, particularly gamma rays from radionuclides, can contribute to the formation of amino acids from simple molecules such as formaldehyde and ammonia. In this study, we investigated the details of gamma-ray-induced amino acid formation, focusing on the effects of different starting materials on aqueous solutions of formaldehyde, ammonia, methanol, and glycolaldehyde with various compositions, as well as hexamethylenetetramine. Alanine and glycine were the most abundantly formed amino acids after acid hydrolysis of gamma-ray-irradiated products. Amino acid formation increased with increasing gamma-ray irradiation doses. Lower amounts of ammonia relative to formaldehyde produced more amino acids. Glycolaldehyde significantly increased amino acid yields. Our results indicated that glycolaldehyde formation from formaldehyde enhanced by gamma rays is key for the subsequent production of amino acids.

Modular development of organelle-targeting fluorescent probes for imaging formaldehyde in live cells.

Formaldehyde (FA) is endogenously generated via fundamental biological processes in living systems. Aberrant FA homeostasis in subcellular microenvironments is implicated in numerous pathological conditions. Fluorescent probes for detecting FA in specific organelles are thus of great research interest. Herein, we present a modular strategy to construct diverse organelle-targeting FA probes by incorporating selective organelle-targeting moieties into the scaffold of a 1,8-naphthalimide-derived FA fluorescent probe. These probes react with FA through the 2-aza-Cope arrangement and exhibit highly selective fluorescence increases for detecting FA in aqueous solutions. Moreover, these organelle-targeting probes, i.e., FFP551-Nuc, FFP551-ER, FFP551-Mito, and FFP551-Lyso, allow selective localization and imaging of FA in the nucleus, endoplasmic reticulum, mitochondria, and lysosomes of live mammalian cells, respectively. Furthermore, FFP551-Nuc has been successfully employed to monitor changes of endogenous FA levels in the nucleus of live mammalian cells. Overall, these probes should represent new imaging tools for studying the biology and pathology associated with FA in different intracellular compartments.

Saccharide formation by sustainable formose reaction using heterogeneous zeolite catalysts.

The formose reaction is a unique chemical reaction for the preparation of saccharides from formaldehyde, a single carbon compound. We applied zeolite materials as heterogeneous catalysts to the formose reaction. The simple addition of Linde type A zeolite containing calcium ions (Ca-LTA) to an aqueous solution of formaldehyde and glycolaldehyde produced saccharides at room temperature. A quantitative analysis performed by high-performance liquid chromatography revealed that triose, tetrose, pentose, and hexose saccharides were produced with few byproducts. Ca-LTA was recovered from the reaction mixture by filtration, and the retrieved zeolite was found to be reusable under the same conditions. The catalytic activity of Ca-LTA was higher than those of conventional calcium catalysts and other solid materials such as silica, alumina, and hydroxyapatite. Several other types of zeolites with different crystal structures and alkali/alkali-earth metal ions also showed catalytic activity for saccharide formation. Based on the analytical results obtained by infrared spectroscopy, temperature-programmed desorption profiles and NMR measurements, we propose a reaction mechanism in which C-C bond formation is promoted by the mild basicity of the oxygen atoms and acidity on the metal ions of the aluminosilicate on the zeolite surfaces with low SiO2/Al2O3 ratios.

Сравнительная оценка токсичности и вирулицидных свойств дезинфектантов, применяемых при работе с вирусом SARS-CoV-2 в изолированных вирусологических лабораториях

The choice of disinfectants and their combinations for the final disinfection of the premises of «infectious» areas of laboratories of biosafety level 3–4, in which work is carried out with viruses with epidemic potential, is important for reducing the toxic effect of these disinfectants on personnel while maintaining 100?% disinfection efficiency. Purpose of the study: to study the toxicity of disinfectants of different groups for cell culture, to select a toxicity neutralizer, to study the virucidal activity of these disinfectants and their combinations against the SARS-CoV-2 virus. Materials and methods: experimental studies were carried out using the reference strain of coronavirus SARS-CoV-2, namely the hCoV-19/Australia/VIC01/2020 (AUS) strain (Wuhan variant), obtained from the State Collection of Causative Agents of Viral Infectious Diseases and Rickettsial Diseases, functioning on the basis of the Federal Budgetary Institution State Scientific Center for Virology and Biotechnology «Vector» of Rospotrebnadzor. The residual infectious activity of the virus was determined by titrating samples in cell culture. To conduct the research, we used a Vero E6 cell culture obtained from the Collection of Cell Cultures of the Federal Budgetary Institution of Scientific Research Center for Virology and Biochemistry «Vector» of Rospotrebnadzor in the form of a 2-day monolayer with a confluency of 95–100?%. Results. As a result of the studies, experimental data were obtained on the dynamics of the virucidal activity of different groups of disinfectants and their combinations against the SARS-CoV-2 virus. The degree of toxicity of disinfectants for Vero E6 cell culture is shown. Optimal combinations of disinfectants and a 40?% aqueous solution of formaldehyde (hereinafter referred to as formalin) have been selected, increasing its disinfection efficiency at an initial concentration halved, which can be used for final disinfection treatment of the premises of isolated virology laboratories conducting work with the SARS-CoV- coronavirus. Conclusion. The results obtained indicate that when using selected combinations of disinfectants to carry out final disinfection with formaldehyde vapors formed during the evaporation of formaldehyde as a result of its heating, a twofold decrease in the initial concentration of formalin is possible, leading to a decrease in its toxic effect on personnel, while maintaining 100?% efficiency disinfection. Keywords: disinfection, disinfectants, formaldehyde, SARS-CoV-2 coronavirus, disinfection efficiency, cytotoxicity.

Impact of a conditioning step during the treatment of wood with melamine-formaldehyde resin on dimensional stabilisation

Abstract The dimensional stabilisation of wood using thermosetting resins relies on the resin uptake into the cell walls. This study tested if a conditioning step after the impregnation and before the final heat-curing enhances the cell wall uptake to improve dimensional stabilisation without increasing the chemical consumption. Small blocks of Scots pine sapwood were vacuum-impregnated with an aqueous melamine formaldehyde solution and conditioned at 33, 70, or 95 % RH for up to 1 week before drying and curing the blocks at 103 °C. However, the conditioning step decreased the cell wall bulking and the moisture exclusion effect compared to the immediate heat curing of the impregnated samples. Analyses of the resin-treated samples by scanning electron microscopy, IR spectroscopy and confocal Raman microspectroscopy provided evidence of wood hydrolysis and polycondensation of the resin within the cell lumen during the conditioning step. Hydrolysis and removal of wood constituents may have counterbalanced the cell wall bulking of the resin. Polycondensation of the resin in the lumen increased its molecule size, which could have hindered the cell wall diffusion of the resin.

Tandem reactions on phase separated MnO2 and C to enhance formaldehyde conversion to hydrogen

Hydrogen production from formaldehyde aqueous solution at room temperature shows a unique advantage regarding the bi-functional reaction route. MnO2 was reported to be an active catalytic material for this process, especially after coating with carbon composite for improved active site distribution. Here, we unravel that the conversion of formaldehyde can be treated as two tandem half-reactions: the oxidative dehydrogenation (ODH) of formaldehyde and the hydrogen evolution reaction (HER). β-MnO2 in a physical mixture with carbon (i.e., XC-72R, graphene) enhances both formaldehyde conversion (from 13% to 19.5%) and hydrogen productivity (from 22.35 μmol mg−1 h−1 to 33.86 μmol mg−1 h−1) by a synergistic effect of the phase separation catalyst in terms of electron redistribution and transport over the active sites. The catalyst examination supported by DFT calculation shows relatively low activation energy and band gap of β-MnO2 + C with a density of states spanning the Fermi level. The discovery of this novel synergistic catalytic effect: a phase separation catalyst with cooperative enhancement, provides new insight into the area of tandem catalysis.

Production of Bitumen Modified with Low-Molecular Organic Compounds from Petroleum Residues. 8. Prospects of Using Formaldehyde Modified Tars in Road Construction

Modification of tars with formalin (37 % aqueous solution of formaldehyde) was carried out using various acids as process catalysts with the aim of obtaining new binding materials for road construction. H2SO4, HCl, H3PO4, and СH3COOH were used as catalysts. The modification process was carried out in the temperature range of 378-403 K and for a duration of 0.6-1.0 h. The rheological properties of tars modified with formaldehyde at 333, 343, and 353 K were studied and a comparison of the rheological properties of the obtained bituminous binder materials with oxidized bitumens was carried out.

Activated metal Bi and La modified SAPO-34 molecular sieve and its photocatalytic degradation of formaldehyde in aqueous solution

Activated metal Bi and La modified SAPO-34 molecular sieve and its photocatalytic degradation of formaldehyde in aqueous solution

Building synergy between Cu and Ag for efficient hydrogen production from formaldehyde reforming

Building a sustainable society requires efficient chemical storage of hydrogen and facile on-demand generation. In this work, hydrogen is spontaneous generated from reforming formaldehyde and water on bimetallic Ag/Cu NWs catalyst, which is synthesized by a simple wet etching method together with electrochemical reduction. The results indicate that O2 can effectively promote H2 generation by forming *OOH specie, and act as a medium for H atom transfer. The synergistic effect between Ag and Cu greatly improves the catalytic activity. Specifically, the adsorption of O2 on Cu sites promotes the dehydrogenation of formaldehyde and proton coupling on Ag sites. Consequently, the Ag/Cu catalyst expresses excellent hydrogen production from aqueous formaldehyde solution at a rate of 12.3 mmol/(gcat.∙min), which surpass the past record. This work clearly explains the synergistic effect mechanism on formaldehyde reforming from the atomic level, providing guidance for the design of highly efficient catalysts for aqueous-phase spontaneous hydrogen evolution reactions.

Thermodynamic modelling of the nature of speciation and phase behaviour of binary and ternary mixtures of formaldehyde, water and methanol

Formaldehyde is a highly reactive chemical that is usually sold and processed in the form of aqueous solutions, with methanol added for stability. In these solutions, formaldehyde reacts with the solvents to form a variety of reaction products, including oligomers. These chemical reactions can occur in the liquid and vapour phases and have a significant influence on the properties of formaldehyde-containing solutions. Of particular interest to industrial applications is the prediction of the vapour–liquid equilibria (VLE) in formaldehyde solutions, considering the chemical reactions. We use the SAFT-γ Mie group-contribution (GC) equation of state to obtain the fluid-phase behaviour of binary and ternary mixtures of formaldehyde with water and methanol. The oligomerisation reactions taking place in aqueous and methanolic solutions of formaldehyde are modelled implicitly using a physical approach, which is possible within the SAFT-γ Mie framework by adding association (reactive) sites that mediate the formation of the reaction products. Using this approach, the nature of the chemical speciation in formaldehyde + water, formaldehyde + methanol and formaldehyde + water + methanol mixtures is studied. A new group, CHO, characterising formaldehyde within the SAFT-γ Mie GC approach, is developed. Experimental data for the VLE in binary mixtures of formaldehyde + water and formaldehyde + methanol are used to obtain the optimal unlike interaction parameters between the corresponding SAFT-γ Mie groups. The newly developed parameters are used to predict the VLE of ternary formaldehyde + water + methanol mixtures for a wide range of temperatures and pressures, with excellent agreement to experimental data. Additionally, the SAFT-γ Mie approach is shown to provide accurate predictions of the distribution of reaction species (oligomers) in binary and ternary mixtures containing formaldehyde.

Synthesis of anti-tuberculosis drugs in a microwave flow reactor

This article describes the first detailed method for the synthesis of the sought-after anti tuberculosis drugs Methazide (2) and Ftivazide (3) in a microwave flow-type reactor. The process was carried out in water, the time of synthesis of Methazide was reduced by a factor of 36 and of Ftivazide by a factor of 24 as compared with known convection prototypes; the replacement of toxic aqueous formaldehyde solution by safer paraformaldehyde was successfully carried out, all of which makes the proposed method consistent with the principles of the “Green Chemistry“ concept.

Gamma-Ray-Induced Amino Acid Formation in Aqueous Small Bodies in the Early Solar System.

Carbonaceous chondrites contain life's essential building blocks, including amino acids, and their delivery of organic compounds would have played a key role in life's emergence on Earth. Aqueous alteration of carbonaceous chondrites is a widespread process induced by the heat produced by radioactive decay of nuclides like 26Al. Simple ubiquitous molecules like formaldehyde and ammonia could produce various organic compounds, including amino acids and complex organic macromolecules. However, the effects of radiation on such organic chemistry are unknown. Hence, the effects of gamma rays from radioactive decays on the formation of amino acids in meteorite parent bodies are demonstrated here. We discovered that gamma-ray irradiation of aqueous formaldehyde and ammonia solutions afforded a variety of amino acids. The amino acid yields had a linear relationship with the total gamma-ray dose but were unaffected by the irradiation dose rates. Given the gamma-ray production rates in the meteorite parent bodies, we estimated that the production rates were reasonable compared to amino acid abundances in carbonaceous chondrites. Our findings indicate that gamma rays may contribute to amino acid formation in parent bodies during aqueous alteration. In this paper, we propose a new prebiotic amino acid formation pathway that contributes to life's origin.

Photoinduced electron-rich CuNi@C/TiO2 catalyst for highly efficient hydrogen production from formaldehyde aqueous solution

Catalytic conversion efficiency from aqueous formaldehyde (HCHO) into hydrogen (H2) on non-noble metal catalysts is much lower than that on noble metal catalysts. Modulating the electronic properties of non-noble metal-based catalysts has been demonstrated an effective approach to improve their catalytic performance. In this work, assisted by light irradiation, photoinduced electron-rich surface structure was designed for the thermal catalytic conversion of HCHO to H2. In detail, a heterostructure of CuNi@C composited with TiO2 was obtained, in which TiO2 can be photoexcited under light irradiation to provide photoinduced electrons onto the surface of CuNi@C. On the photoinduced electron-rich surface of the CuNi@C/TiO2 heterostructure, the H2 evolution rate reached 254.65 mmol h−1 g−1, which was 1.88 times higher than that on CuNi@C. It is worth noting that the catalytic HCHO conversion efficiency outperforms the current reported non-noble metal catalysts for this reaction. Combining with density functional theory (DFT) calculations and experimental studies, it is concluded that the electron-rich CuNi@C dramatically reduced the activation energies of the dissociation of HCHO and H2O and accelerated the overall reaction rate.

Design of a process for the provision of methanolic formaldehyde solutions of low water content from aqueous formaldehyde solutions

Formaldehyde is an essential and widely used intermediate in the chemical industry. It is mostly handled and stored in aqueous solutions. However, some processes require methanolic formaldehyde solutions of low water content as feedstock, among them the production of the synthetic fuel poly(oxymethylene) dimethyl ether (OME). This work presents the conceptual design for a process to provide methanolic formaldehyde solutions with high yield, avoiding aqueous solution as a side product. The separation of water is achieved by a combination of thin-film evaporation and distillation. Process simulations and optimal operating points with respect to energy demand and residual water content are determined. A residual water content of 0.09 g/g in the product could not be undercut.

The Effects of Formalin (Formyl Tetrahydrofolate) on CDK1 Protein on the Oocyte Maturation Process: Quantitative Structure Toxicity Relaionships (QSAR) In Silico Analysis

Formalin is an aqueous solution of formaldehyde. Formalin can trigger the formation of ROS causingoxidative stress, and has an impact on changes in theCDK1 protein which has a role in oocyte maturation.The researchers were able to predict in silico mutagenicityand formyl tetrahydrofolate toxicity to CDK1protein in oocyte cell maturation using the Molegro VirtualDocker computer program and the comparisoncompound fipronil. The receptor CDK1/CyclinB1/CKS2,code PDB: 4Y72, was used with the LZ9 ligand.Using the pkCSM online tool program, investigate in silicoqualitative structure activity relationships (QSAR)to predict pharmacokinetic properties (ADME), toxicity ofpotential medicinal compounds, environmentalcontaminants, and poisons. The bond energy resulting from docking between formalin, LZ9 ligand, andfipronil comparators at the target receptor was compared for data analysis. The more stable the bonds are,the lower the bond energy of the ligands to the target receptor. The bond energy of formalin = -130.832kcal/mol, ligand LZ9 301 [A] = -120.118kcal/mol, and fipronil = -101.069 kcal/mol, according to the in silico testresults. Formalin has the ability to increase ROS production and affect CDK1 protein more than LZ9 andfipronil ligands, according to the above test results. Thefindings of the in silico test utilizing the pkCSMonline tool software demonstrate that formyl tetrahydrofolate molecules are hazardous and quicklyenterand absorb into the human body.

AMINOMETHYLATION OF DIHYDROXYACETOPHENONES

Aminomethylation of trifunctional 2.5-dihydroxyacetophenone (2.5-DHA) and 2.4-dihydro¬xy¬aceto-phenone (2.4-DHA) by free primary and secondary amines in the presence of formaldehyde has been conducted for the first time. It has been established that 2.5-DHA is aminomethylated with secondary heterocyclic amines - piperidine and morpholine and with aqueous formaldehyde solution in alcohol medium at 500C. The reaction proceeds simultaneously via all three functions forming stable C,O-substitution products − β-amino-2-aminomethoxy-4-aminomethyl-5-hydroxypropiophenones. The aminomethylation reaction of 2.4-DHA proceeds by phenolic function only under the action of methylene bis-amines piperidine and morpholine in absolute alcohol at 200C with the formation of 2.4-dihydroxy-3-aminomethylacetophenones. Aminomethylation of 2.4-DHA with primary aromatic amines - n-to¬luidine and n-anisidine proceeds in absolute alcohol under the action of formaldehyde in the form of paraform in the presence of catalytic amounts of KOH at 500C. The reaction products are 3.4-dihydro-2H-1.3-benzoxazines. 2.5-DHA does not react with primary aromatic amines and formaldehyde. The composition and structure of compounds synthesized have been established according to the data of ele¬mental and spectral methods of analysis

Effects of formaldehyde ( Parasite‐S ®) on biofilter nitrification from a cold and a warm freshwater RAS

The effect of Parasite-S® (an aqueous formaldehyde solution) on the nitrification processes of biofilters was evaluated in two recirculating aquaculture systems (RASs). Rearing tanks in the warmwater RAS contained yellow perch (Perca flavescens) and grass carp (Ctenopharyngodon idella) with an initial weight of 166.8 kg and a mean density of 39.5 kg/m3. Rearing tanks in the coldwater RAS contained rainbow trout (Oncorhynchus mykiss) and lake trout (Salvelinus namaycush) with an initial weight of 1377.8 kg at a system density of 41.9 kg/m3. Parasite-S® was administered to the entire system on four consecutive days in both trials to achieve a nominal concentration of 14.8 mg/L formaldehyde (40 mg/L formalin) at the biofilter. Removal efficiencies for total ammonia nitrogen (TAN) and nitrite nitrogen were measured as indicators of biofilter nitrification processes. The active ingredient in Parasite-S®, formaldehyde, was measured until it was below the method detection limit of 0.8 mg/L. TAN volumetric removal rate was significantly decreased in both systems after formaldehyde addition and remained below pre-exposure efficiency in the coldwater RAS. Nitrite nitrogen volumetric removal rate was not significantly different, but the slope and intercepts were less after formaldehyde addition indicating an effect on the nitrifying bacteria. Although removal rates were decreased, no mortality occurred after four consecutive formaldehyde indefinite bath exposures in either system.