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Sulfation of wheat straw soda lignin by the sulfamic acid–urea mixture in different solvents has been investigated for the first time. The effect of a catalyst used in the lignin sulfation process on the yield of the lignin sulfates and sulfur content in them has been explored. It has been found that the optimal medium for the lignin sulfation with sulfamic acid is dioxane and, in the presence of a catalyst, urea. Although the sulfated lignins obtained using the reaction in dimethyl sulfoxide and diglyme have the maximum sulfur contents (11.2% and 9.9%, respectively), these products are difficult to isolate and purify, which complicates the use of these solvents. Sulfated lignin obtained in the dioxane medium has a high (10.1%) sulfur content and is easy to isolate and purify. The incorporation of sulfate groups into the lignin structure has been confirmed by the infrared and nuclear magnetic resonance spectroscopy investigations. In the infrared spectra of sulfated lignin, characteristic absorption bands at 800–860 and 1260–1200 cm−1 appear. The dominant substitution of aliphatic hydroxyl groups has been confirmed by the nuclear magnetic resonance spectroscopy study. It has been found that, during the modification and purification of lignin, the latter is fractionated, which results in the redistribution of molecular weights toward the high molecular-weight region, as well as the removal of some low-molecular-weight components, which is reflected in a decrease in the number of signals in the nuclear magnetic resonance spectra.

In this work we analyze the dosimetric properties of sulfamic acid irradiated by X-rays photons (6MV and 18MV), electrons (6 MeV and 18 MeV), protons (68 MeV) and neutrons (from 0 to 400 MeV). After irradiation, the samples are analyzed by Electronic Paramagnetic Resonance “EPR” to measure the applied radiation dose. For all used irradiations, the obtained results show that the measurable threshold dose is 0.25 Gy. The correlation between measured dose and EPR signal is linear in the dose range from 0 to 20 Gy with a correlation coefficient above 0.999. Sulfamic acid seems to be more sensitive to photons and electrons irradiations (approximately 20% more sensitive) than to protons and neutrons irradiations. The overall uncertainty (2σ) of dose monitoring is approximately 6% by peak to peak method and 5% by double Integration method. The time dependence indicates a low fading effect during the storage period (4% of fading after two months of storage). These results prove that sulfamic acid is a promising dosimeter for use in the field of radiotherapy including hadrontherapy, These results prove that sulfamic acid is a promising dosimeter for use in the field of radiotherapy including hadrontherapy, in particular for small field treatment and out off-field dose estimation.

Compounds adsorbed onto PM10 in the air near the cement plant were determined. Several side reactions that occur in the hot flue gas stream at the same time as the actual main reactions are also possible. This leads to the formation of traces of organic nitrogen compounds. For the GC/MS determination of polar organic compounds silylation as a derivatization method was used. Organic compounds detected are derivatives of sugars, sugar alcohols, and mono-, di- and tri-carboxylic acids. The composition is characteristic for pollution of the urbane atmosphere. Nitrogen organic compounds formed during the urea thermolytic process in hot cement kiln gases represent parabanic acid, 5-hydroxyhydantoin, 4,5-dihydroxyhydantoin, 5-oxoproline, and cyanuric acid. The inorganic part of aerosols detected includes oxyanions of sulfamic acid, sulfate, sulfite, phosphate, and vanadate(V) with ammonium as a cation. Chemical compositions of particles are crucial to assess the health impacts since the biological responses to aerosols are not always linked with major constituents but rather with toxicologically potent minor components.

Razuprotafib, a sulphamic acid-containing phosphatase inhibitor, is shown in vivo to undergo enzymatic oxidation and methylation to form a major metabolite in monkey and human excreta with an m/z- value of 633.LC-MS/MS analysis of samples derived from incubations of razuprotafib with human liver microsomes and recombinant CYP2C8 enzyme has elucidated the metabolic pathway for formation of the thiol precursor to the S-methyl metabolite MS633 (m/z- 633).Under in vitro conditions, the major pathway of razuprotafib metabolism involves extensive oxidation of the thiophene and phenyl rings.A single oxidation takes place at one of the phenyl groups. Multiple oxidations occur at the thiophene moiety: initial oxidation results in the formation of a thiolactone followed by a second oxidation giving rise to an S-oxide of the thiolactone, which is further metabolised to the ring-opened form and ultimate formation of a thiol (m/z- 619).An additional mono-oxidation pathway involves epoxidation of the thiophene followed by hydrolysis to a diol.The thiol and diol metabolites are trapped by the addition of a nucleophilic trapping agent, 3-methoxyphenacyl bromide (MPB), giving adducts with m/z- 767.The thiol is a likely precursor to the major in vivo razuprotafib metabolite, MS633.

Sulfation of birch wood xylan in 1,4-dioxane by sulfamic acid in the presence of urea at 90 and 100 °C was studied for the first time. The effect of the duration of xylan sulfation on the yield of xylan sulfates and the sulfur content in them was studied. It was found that the sulfur content in the obtained xylan sulfates increases from 12.5 to 17.5 wt% with an increase in the duration of sulfation from 2 to 4 hours. The structure of initial and sulfated xylan was studied by FTIR and NMR spectroscopy. The ease of purification of the obtained xylan sulfates from 1,4-dioxane in comparison with the purification of xylan sulfates obtained by sulfation in pyridine and N, N‑dimethylformamide is an advantage of the proposed method of xylan sulfation

Sulfated cellulose derivatives are biologically active substances with anticoagulant properties. In this study, a new sulfated diethylaminoethyl (DEAE)-cellulose derivative has been obtained. The effect of a solvent on the sulfation process has been investigated. It is shown that 1,4-dioxane is the most effective solvent, which ensures the highest sulfur content in DEAE-cellulose sulfate under sulfamic acid sulfation. The processes of sulfamic acid sulfation in the presence of urea in 1,4-dioxane and in a deep eutectic solvent representing a mixture of sulfamic acid and urea have been compared. It is demonstrated that the use of 1,4-dioxane yields the sulfated product with a higher sulfur content. The obtained sulfated DEAE-cellulose derivatives have been analyzed by Fourier transform infrared spectroscopy, X-ray diffractometry, and scanning electron and atomic force microscopy, and the degree of their polymerization has been determined. The introduction of a sulfate group has been confirmed by the Fourier transform infrared spectroscopy data; the absorption bands corresponding to sulfate groups have been observed in the ranges of 1247-1256 and 809-816 cm-1. It is shown that the use of a deep eutectic solvent leads to the side carbamation reactions. Amorphization of DEAE-cellulose during sulfation has been demonstrated using X-ray diffractometry. The geometric structure of a molecule in the ground state has been calculated using the density functional theory with the B3LYP/6-31G(d, p) basis set. The reactive areas of DEAE-cellulose and its sulfated derivatives have been analyzed using molecular electrostatic potential maps. The thermodynamic parameters (heat capacity, entropy, and enthalpy) of the target sulfation products have been determined. The HOMO-LUMO energy gap, Mulliken atomic charges, and electron density topology of the title compound have been calculated within the atoms in molecule theory.

For the first time, the process of birch ethanol lignin sulfation with a sulfamic acid-urea mixture in a 1,4-dioxane medium was optimized experimentally and numerically. The high yield of the sulfated ethanol lignin (more than 96%) and containing 7.1 and 7.9 wt % of sulfur was produced at process temperatures of 80 and 90 °C for 3 h. The sample with the highest sulfur content (8.1 wt %) was obtained at a temperature of 100 °C for 2 h. The structure and molecular weight distribution of the sulfated birch ethanol lignin was established by FTIR, 2D 1H and 13C NMR spectroscopy, and gel permeation chromatography. The introduction of sulfate groups into the lignin structure was confirmed by FTIR by the appearance of absorption bands characteristic of the vibrations of sulfate group bonds. According to 2D NMR spectroscopy data, both the alcohol and phenolic hydroxyl groups of the ethanol lignin were subjected to sulfation. The sulfated birch ethanol lignin with a weight average molecular weight of 7.6 kDa and a polydispersity index of 1.81 was obtained under the optimum process conditions. Differences in the structure of the phenylpropane units of birch ethanol lignin (syringyl-type predominates) and abies ethanol lignin (guaiacyl-type predominates) was manifested in the fact that the sulfation of the former proceeds more completely at moderate temperatures than the latter. In contrast to sulfated abies ethanol lignin, the sulfated birch ethanol lignin had a bimodal and wider molecular weight distribution, as well as less thermal stability. The introduction of sulfate groups into ethanol lignin reduced its thermal stability.

The coproduction of 5-hydroxymethylfurfural (5-HMF) and furfural (FUR) via the direct hydrolysis of holocellulose analogue composed of cellulose and hemicellulose was investigated. The effects of catalyst amount, solvent type and amount, reaction temperature and time using sulfamic acid with dual active sites as catalyst were also studied. The yields of 5-HMF and FUR at 37.2% and 62.0% were obtained with the volume ratio of γ-valerolactone to water of 25:1 at 180 oC for 3 h. The conversion of corn cob holocellulose and wheat straw holocellulose to furfural compounds was then carried out under the identical conditions. Yields of 5-HMF at 26.6% and 28.5%, and yields of FUR at 34.5% and 26.1% were obtained, respectively. A possible mechanism for the coproduction of 5-HMF and FUR from holocellulose was proposed. It is believed that there is a synergistic effect between the hydrolysis of cellulose and hemicellulose during the conversion of holocellulose.

Biological macromolecules are proven to be potential green corrosion inhibitors because of their outstanding structural features and eco-friendliness. This study is aimed at enhancing their corrosion mitigation capabilities by converting them into nanoparticles. This is the first work where nanoparticles of biological macromolecules are exploited for corrosion mitigation studies. Glycogen nanoparticles (GLY-Np) were synthesized by microwave�mediated nanoprecipitation method and characterized by ATR–FTIR, XRD, UV–Visible Spectroscopy, FESEM analysis, EDX, TEM, and Zeta potential measurements. They are used as an eco-friendly inhibitor for corrosion control of zinc in sulfamic acid (NH2SO3H). The electrochemical study was a primary experimental tool employed for corrosion rate measurement. Conditions were optimized to obtain maximum inhibition efficiency by varying concentrations of inhibitor and temperature. Activation and thermodynamic parameters were eval�uated and discussed in detail. A suitable adsorption isotherm was proposed to fit the experimental results. Adsorption of the inhibitor was confirmed by SEM, EDX, and AFM techniques. The inhibition efficiency of 92% was obtained for 0.02 gL− 1 GLY-Np. Thus, GLY-Np turned out to be an effective green inhibition with economic benefits

A method has been developed for the synthesis of granular polymeric materials with immobilized N-chloro-sulfonamide groups. Commercially available resin polymers widely applied for the preparation of ion exchangers have been used as polymer carriers. The elaborated technological conditions make it possible to modify these resins with a high conversion degree, without deteriorating the strength characteristics, and with the possibility of regulating the concentration of active chlorine over a wide range (up to 11 % w/w). The structure of the synthesized polymers was confirmed by IR spectroscopy data. To determine the concentration of functional groups, a special method of iodometric titration has been developed. The processes of emission of active chlorine from synthesized polymers into aqueous solutions have been studied. It has been shown that this process significantly depends on the composition of the solution: no release of active chlorine into distilled water is observed, and when using tap water, its concentration is reached 5–8 mg/dm3 and remains up to 30 days when the granules are in water. The processes of activation of active chlorine emission by compounds of amine nature have been studied, the corresponding kinetic curves of the dependence between change in the concentration of active chlorine in solution and the used activator are presented. It has been found that the nature of the used activator strongly affects, among other things, the stability of the obtained chlorine-active solutions. Taurine and sulfamic acid are found to be the optimal activators for obtaining stable solutions of active chlorine of high concentration. The composition of the N-chloro-taurin solution obtained in this way has been additionally analyzed by UV spectroscopy. Thus, the synthesized polymers make it possible to quickly in situ obtain high-purity solutions of active chlorine without the use of special electrochemical equipment. The polymers themselves are compact, stable, and can be repeatedly regenerated

A novel type of polyacid corrosion inhibitor (PCI) was synthesized from the residue of 2-vinylpyridine, which could reduce the cost of hazardous waste disposal in production enterprises, and solve the environmental pollution caused by residue. Herein, the components of the residue were analyzed and a special solvent is selected to dissolve it. Then, synergistic experiments of the residual solution with different inhibitor were carried out to select the corrosion inhibitor components, and the optimal ratio of each component was determined by orthogonal experiments. The performance of PCI was estimated by weight loss method, and its electrochemical type was detected by electrochemical experiments. It indicated that the main components of 2-vinylpyridine residue are pyridine derivatives and hydrocarbons. The developed PCI is composed by four components, which could be suitable for HCl, citric acid, sulfamic acid, other acid systems, and has good corrosion inhibition effect on carbon steel, brass, and other materials. The corrosion rate of N80 carbon steel can reach to 0.5491 g m−2 h−1 at 60 ℃ in 5% HCl, which fully meets the requirements of China national standards. The electrochemical polarization curve showed that PCI is a kind of highly effective mixed inhibitor, which can inhibit both cathode and anode simultaneously.

The effect of temperature and duration of sulfation of birch wood xylan by sulfamic acid in N, N-dimethylformamide (DMF) medium in the presence of urea on the yield of sulfated xylan and on the sulphur content was studied. By mathematical optimization, the sulfation conditions have been established allowing to achieve a high yield of the obtained xylan sulfates with a high sulphur content. Under optimal sulfation conditions: temperature 100±3 °C, duration 1.5 hours, the yield of sulfated xylan reaches to 63% mas. and the content of sulfur – 17.6% mas. The presence of sulfate groups in sulfated xylan samples obtained under optimal conditions was confirmed by elemental analysis and FTIR and 13C NMR spectroscopy.

Defect passivation has shown an essential role in improving the efficiency and stability of perovskite solar cells (PSCs). Herein, an efficient and low-cost π-conjugated sulfamic acid additive, 4-aminobenzenesulfonic acid (4-ABSA), is used to realize durable defect passivation of PSCs. The incorporation of 4-ABSA not only constructs a compact and smooth perovskite film but is also capable of passivating both negative- and positive-charged defects derived from under-coordinated lead and halogen ions. Besides, the π-conjugated system in 4-ABSA can induce preferred perovskite crystal orientation and stabilize the coordination effect between 4-ABSA and perovskite grains. As a result, the inverted planar PSC incorporated with 4-ABSA additives demonstrates an improved power conversion efficiency (PCE) from 18.25 to 20.32%. Moreover, this 4-ABSA passivation agent also enhances the stability of devices, which retains 83.5% of its initial efficiency under ambient condition at 60 °C after 27 days. This work provides a π-conjugated sulfamic acid for durable defect passivation of perovskite optoelectronic devices.

The synthesis of galactoglucomannan sulfates using a sulfamic acid/urea mixture in 1,4-dioxane was studied for the first time. The effect of the galactoglucomannan sulfation time and temperature on the sulfur content in the galactoglucomannan sulfates was investigated. The introduction of sulfate groups into the galactoglucomannan structure was confirmed by the elemental analysis and Fourier transform infrared spectroscopy. The initial and sulfated galactoglucomannans were identified by X-ray diffraction, electron microscopy, and gel permeation chromatography. The thermal analysis has shown that sulfated galactoglucomannan, after the endothermic peak related to the moisture removal, yields a pronounced high-intensity exothermic peak with a maximum at 216 °C, and above 230 °C, the heat absorption effect (endothermic peak) characteristic of decomposition of the parent substance in the range of 230–335 °C is observed. According to the scanning electron microscopy data, the initial galactoglucomannan consists of irregular asymmetric particles with an average size from 400 to 900 µm, and the sulfated galactoglucomannan ammonium salt consists of particles 200–500 µm in size with different shapes. It was shown by gel permeation chromatography that, after the sulfation process, the main galactoglucomannan peak shifts toward higher molecular masses (from 24 to 26 kDa).

Surface functionalization of blast furnace slag with sulfamic acid (a zwitterion) was performed for the removal of Cr3+ and methylene blue dye (MB) from water samples. The slag functionalization process was optimized using Response Surface Methodology Design. Statistical analysis of the parameters that include the sulfamic acid amount (A), reaction time (B), and temperature (C) revealed that (A) increase had a negative effect on the adsorption of both pollutants by the zwitterion slag, whereas (B) and (C) increase presented a positive impact. At the optimum condition of 2 g sulfamic acid amount, 50 min reaction time and 37 °C temperature, the prepared slag showed a removal efficiency of more than 90% for both Cr3+ and MB. Surface characterization by SEM/EDS, FTIR, XPS and surface area analyser, showed an improvement in surface properties and the incorporation of zwitterionic NH2+ and S O groups of sulfamic acid. Adsorption isotherm and kinetic studies conducted with the zwitterion slag showed the adsorption process was suited to Freundlich isotherm model and pseudo-second-order kinetic model. The thermodynamic study conducted revealed the spontaneity of the process based on the calculated negative ΔG (Gibb’s free energy) values. The prepared zwitterion slag offered easy regeneration with dilute HCl solution and showed a considerable removal (Cr3+: 65% and MB: 80%) for both pollutants even after 3 cycles of usage.

Present investigation deals with the synthesis and density functional theory study (DFT) of a Biginelli adduct; 6-methyl-2-oxo-4-phenyl-1,2,3,4-tetrahydropyrimidine-5-carboxylate (MOPTHPC). The synthesis of a MOPTHPC has been carried out by the reaction of benzaldehyde, ethyl acetoacetate and urea in ethanol 70-80 ℃ under stirring condition in presence of catalytic amount of sulfamic acid. The structure of a synthesized chalcone is affirmed on the basis of 1H NMR and 13C NMR. The geometry of a MOPTHPC is optimized by using the density functional theory method at the B3LYP/6-311G(d,p) basis set. The optimized geometrical parameters like bond length and bond angles have been computed. Quantum chemical parameters have been determined and examined. Molecular electrostatic surface potential (MESP) surface plot analysis has been carried out at the same level of theory. Mulliken atomic charge study is also discussed in the present study.

The deterioration of iron-based alloys, especially mild steel (MS) is one amongst the most challenging problems faced in various chemical industries. The present work focuses on the potential activity of a naphthalimide derivative namely 2-(2-hydroxyethyl)benzo[de]isoquinoline-1,3-dione (HBIQ) as corrosion inhibitor for MS in sulfamic acid (SA) medium in the temperature range from 303 to 323 K. Potentiodynamic polarization (PP) and electrochemical impedance spectroscopy (EIS) were employed in the experimental measurement and HBIQ exhibited 89% inhibition at its optimum concentration. HBIQ demonstrated electrostatic interactions with MS surface and behaved as a mixed type of inhibitor by obeying Langmuir’s isotherm model. Surface characterization of uninhibited and inhibited MS specimens combined with elemental analysis data provided clear evidences for the formation of a protective adsorption layer of HBIQ on MS surface. Spectral analysis such as Ultraviolet visible and Fourier Transform Infra-red spectral analyses were carried out in order to confirm the adsorption of HBIQ on to the metal surface. The density functional theory calculations supported the experimental results and indicated the contribution of delocalized π-electrons in the naphthalimide unit and the lone-pair electrons of oxygen in the carbonyl and hydroxyl group for improved adsorption of HBIQ onto MS surface, thereby reducing the corrosion of the alloy in SA environment. Graphic abstract

Sulfamic acid 2-Aminobenzothiazole-6-carboxylic acid functionalized Fe3O4 nanoparticles as a novel organic-inorganic hybrid heterogeneous catalyst were manufactured and characterized by FT-IR, XRD,...

Cellulose sulfates are important biologically active substances with a wide range of useful properties. The development of new methods for the production of cellulose sulfates is an urgent task. In this work, we investigated ion-exchange resins as catalysts for the sulfation of cellulose with sulfamic acid. It has been shown that water-insoluble sulfated reaction products are formed in high yield in the presence of anion exchangers, while water-soluble products are formed in the presence of cation exchangers. The most effective catalyst is Amberlite IR 120. According to gel permeation chromatography, it was shown that the samples sulfated in the presence of the catalysts KU-2-8, Purolit s390 plus, and AN-31 SO42− underwent the greatest degradation. The molecular weight destribution profiles of these samples are noticeably shifted to the left towards low-molecular-weight compounds with an increase in fractions in the regions Mw ~2.100 g/mol and ~3.500 g/mol, indicating the growth of microcrystalline cellulose depolymerization products. The introduction of a sulfate group into the cellulose molecule is confirmed using FTIR spectroscopy by the appearance of absorption bands at 1245–1252 cm−1 and 800–809 cm−1, which correspond to the vibrations of the sulfate group. According to X-ray diffraction data, amorphization of the crystalline structure of cellulose is observed during sulfation. Thermal analysis has shown that with an increase in the content of sulfate groups in cellulose derivatives, thermal stability decreases.

The abuse of toxic organic solvents and surfactants has caused immeasurable damage to human health and the environment. Therefore, based on the concept of green chemistry, developing a new type of nano-based pesticide formulation that does not contain harmful additives is urgent for sustainable pest management. Herein, we report two natural small molecular substances, spinosad (SSD) and sulfamic acid (SA), that were self-assembled into SSD-SA nanoparticles (SSD-SA NPs) through noncovalent interactions without involving any organic solvents or carriers. The results showed that the optimized mass ratio of SA to SSD was 1 : 4 at pH 5 and 35 °C in aqueous solution for the formation of SSD-SA NPs. The core–shell structured nanospheres with particle sizes of around 7 nm had excellent physical and chemical properties, such as strong positive charges (+47.8 mV) and good surface activity. SSD-SA NPs exhibited good quick-acting performance against Plutella xylostella larvae and Frankliniella occidentalis, and the insecticidal activities of SSD-SA NPs were significantly higher than that of the commercial SSD suspension. The genotoxicity evaluation showed that the genotoxicity of SSD to Vicia faba was reduced by a combination of self-assembly technologies and thus SSD-SA NPs posed a low risk to plant cells. These small molecular self-assembled SSD-SA NPs developed by a simple and green preparation process would have great potential for application in sustainable pest management.

In the current work, the corrosion behaviors of Ti-6Al-4V alloys manufactured using spark plasma sintering (SPS), selective laser melting (SLM) and electron beam melting (EBM) techniques are comparably investigated using aircraft deicer (10% sulfamic acid cleaning solution, 10-SACS). The corrosion resistance of different Ti-6Al-4V samples is mainly characterized using electrochemical measurements and immersion tests. The traditional SPS Ti-6Al-4V alloy has a stronger corrosion resistance compared to the SLM Ti-6Al-4V alloy, and the one manufactured using the EBM technique is the most vulnerable among all samples tested. Based on the X-ray diffraction (XRD) measurements, the β-phase constitution fraction of SPS Ti-6Al-4V is 11.8%, while those of SLM and EBM Ti-6Al-4V alloys are 5.3% and 2.6%, respectively. The corrosion resistance of Ti-6Al-4V alloys against 10-SACS is found to be positively correlated to the β phase composition. In addition, a high density of coarse grain boundaries is also partially beneficial in improving the corrosion resistance in the SPS sample. This work paves a way for the practical application of additive manufactured Ti-6Al-4V alloys to be used in harsh environments.

A high-temperature proton exchange membrane was fabricated based on polyvinylidene fluoride (PVDF) and polyvinylpyrrolidone (PVP) blend polymer nanofibers. Using electrospinning method, abundant small ionic clusters can be formed and agglomerated on membrane surface, which would facilitate the proton conductivity. To further enhance the conductivity, phosphoric acid (PA) retention as well as mechanical strength, sulfamic acid (SA)-doped metal–organic framework MIL-101 was incorporated into PVP-PVDF blend nanofiber membranes. As a result, the anhydrous proton conductivity of the composite SA/MIL101@PVP-PVDF membrane reached 0.237 S cm−1 at 160 °C at a moderate acid doping level (ADL) of 12.7. The construction of long-range conducting network by electrospinning method combined with hot-pressing and the synergistic effect between PVP-PVDF, SA/MIL-101 and PA all contribute to the proton conducting behaviors of this composite membrane.

A comparison of IR spectra and molecular weight distribution of arabinogalactan sulfates as sodium and ammonium salts obtained using various sulfating reagents was performed. According to the data, sulfated derivatives of arabinogalactan differ from each other in the nature of hydrogen bonds and molecular weight distribution. Using coagulological tests during activation of coagulation of platelet-poor human plasma in vitro, the anticoagulant properties of sulfated arabinogalactan derivatives in various salt forms differing in the preparation method, sulfation degree, and molecular weight were studied. It was found that the sample in the form of the sodium salt of sulfated arabinogalactan (SAG 1) with a sulfur content of 13.2 wt % and a polydispersity degree of 1.52 exhibited twofold greater anticoagulant activity than the sample in the form of the ammonium salt of sulfated arabinogalactan (SAG 2) with a sulfur content of 6.6 wt % and a polydispersity degree of 1.30. The antithrombin (aIIa) activity of the samples obtained by sulfation with a complex of pyridine and sulfuric anhydride (SAG 1) and a complex of sulfamic acid (SAG 2) was 23.42 ± 1.86 and 10.20 ± 1.50 U/mg, respectively; the value of the antifactor Xa activity of SAG 1 and SAG 2 was 2.13 ± 0.42 and 0.37 ± 0.08 U/mg; the aIIa/aXa ratio for SAG 1 and SAG 2 was 11 and 28, respectively. The antifactor Xa (aXa) activity of SAG, which is lower than that of unfractionated heparin (UFH), and a high aIIa/aXa activity ratio may contribute to less provocation of bleeding by SAG samples compared to UFH.

Ecto-5'-nucleotidase (ecto-5'-NT, CD73) inhibitors are promising drug candidates for cancer therapy. Traditional efforts used to inhibit the ecto-5'-nucleotidase have involved antibody therapy or development of small molecule inhibitors that can mimic the acidic and ionizable structure of adenosine 5'-monophosphate (AMP). Herein, we report an efficient, environment friendly route for the synthesis of non-nucleotide based small molecules, i.e., substituted spirooxindole derivatives 9a-9l and investigated their inhibitory potential on human and rat recombinant ecto-5'-nucleotidase isozymes. These attempts have resulted in the identification of compound 9f (IC50 = 0.15 ± 0.02 μM) inhibitor on h-ecto-5'-NT which showed 280-fold higher inhibition and compound 9h (IC50 ± 0.19 ± 0.03 μM) on r-ecto-5'-NT with 406-fold enhanced inhibition than reference standard sulfamic acid. Moreover, in silico studies were carried out to assess binding interactions of potent compounds within enzyme active sites and demonstrated excellent correlation with the experimental findings.

Pyrimidines constitute an important class of six-membered heterocyclic compounds containing two nitrogens, which are widely distributed in natural products such as nucleic acids 1 and vitamin B1. 2...

1-Aroyl-3,5-diaryl-1H-pyrazoles were synthesized by oxidative cyclization of chalcones with benzohydrazide and 4-nitrobenzohydrazide using sulfamic acid as a catalyst. The corresponding chalcones were prepared by condensation of aromatic aldehydes with acetophenones in PEG-400 in the presence of potassium hydroxide. Some representative features of the proposed procedure include exceptional regioselectivity, comparatively short reaction time, operational simplicity, and no need of external oxidant. The synthesized pyrazole derivatives were screened as antibacterial agents against Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, and Salmonella typhi by the agar well diffusion method. Attempts were made to compute specific heat capacity of the synthesized pyrazole derivatives as a function of temperature using TGA–DSC in order to avail thermodynamic database for these biologically relevant heterocycles.

Impact on the aquatic medium of the number of inorganic additives that are part of the foaming agents for firefighting is considered in paper. The influence of the most widespread inorganic components on aquatic organisms is analyzed. Significant variability of data is noted. It is proved that the magnesium and sodium chlorides are the safest for the environment and the most dangerous ones are aluminum compounds and sulfamic acid. Inorganic additives based on aluminum, sulfamic acid and sodium bicarbonate are the most dangerous for aquatic living organisms, in the short and long term, and the safest compounds are magnesium and sodium chlorides

Supported 3-(3-sulfamic acid imidazolium trifluoroacetate)propyl triethoxysilane on magnetic nanoparticles as a novel nanocatalyst was synthesized and characterized by FT-IR, XRD, TGA, SEM, TEM and VSM techniques. The catalytic activity of the magnetic catalyst was studied through one-pot synthesis of triazole quinazolinones and fused pyrimidine derivatives via one-pot multi-component reactions under thermal conditions. This catalyst demonstrated excellent catalytic properties with high percentage in short reaction times, low cost and easily separated using an external magnet and reusable without significant loss of its catalytic efficiency.

The profitability and sustainability of future biorefineries are dependent on efficient feedstock use. Therefore, it is essential to improve the lignocellulosic utilization efficiency when using lignocellulosic biomass. In this research, a novel corn stover (CS) pretreatment process was established and the effectiveness was verified via d-lactic acid fermentation. The results indicated that after pretreatment with 4% sulfamic acid and 3% sodium chloride solutions (SA/NaCl) at 80 °C for 60 min, and enzymatic hydrolysis with 20 FPU/g cellulase for 72 h, the glucose concentration was14.57 g/L, the cellulose transformation rate was 97.56%, and 56.93% of the solid recovery rate. The concentration of d-lactic acid reached 45 g/L after fermentation for 72 h at 42 °C. In conclusion, SA/NaCl was a safe to use, easy to transport, and more promising CS pretreatment catalyst than sulfuric acid and hydrochloric acid.

The “green” synthesis of galactomannan sulfates using a sulfamic acid–urea mixture has been studied for the first time. The effect of the time and temperature of the galactomannan sulfation process on the degree of substitution of galactomannan sulfates has been investigated. It is shown that, at a temperature of 70 °C with an increase in the process time up to 120 min, the degree of substitution increases up to 0.70. An increase in the process temperature up to 80 °C leads to the production of galactomannan sulfates with a degree of substitution of 1.67. With a further increase in the process temperature to 90 °C, the galactomannan structure is partially destructed, and the degree of substitution decreases. Embedding of the sulfate groups into the galactomannan structure has been confirmed by elemental analysis and Fourier-transform infrared spectroscopy. In addition, the initial and sulfated galactomannans have been characterized by X-ray diffraction, scanning electron microscopy, atomic force microscopy, and gel permeation chromatography. The thermal analysis shows that the initial galactomannan exhibits endothermic peaks at 254 and 294 °C and an exothermic peak at 315 °C, while sulfated galactomannan exhibits endothermic peaks at 209 and 275 °C and an exothermic peak at 281 °C. Using atomic force microscopy, it has been shown that the sulfated galactomannan film consists of spherical particles with an average diameter of 200–300 nm; according to the phase contrast data, it has the uniform composition without extraneous impurities.

The process of abies ethanol lignin sulfation with sulfamic acid in 1,4-dioxane medium in the presence of urea was optimized by calculation methods. The influence of such factors, as the ratio of lignin/sulfating complex (L/SC), temperature and time of the sulfation process on the sulfur content in the resulting sulfated ethanol lignin and its yield, has been established. The variance analysis of the obtained mathematical models testifies their good predictive properties. The optimal conditions of abies ethanol lignin sulfation process, which provide the formation of water-soluble sulfated lignin with a high yield (to 100 % wt.) and sulfur content (up to 7.9 % wt.), have been established. They are: temperature of 95-100 °C, the ratio L/SC 1:2,3-1:2:9 and the time of the process 119-137 minutes

The corrosion inhibition effects of the 2-undecyl-N-carboxymethyl-N-hydroxyethyl imidazoline on simple steels were indagated in 8 wt.% NH2SO3H media using loss of weight and electrochemical methods in conjunction with adsorption and DFT researches. The anti-corrosion effect of UHCI acquired from EIS study is great and the maximum anti-corrosion efficiency could reach 90.15%. The sorption of UHCI on simple steel conforms to the Langmuir sorption equation. The DFT studies reveal that UHCI is firmly chemisorbed upon the simple steel by the Fe…O σ-type dative bonds and isolates the contact between simple steel and NH2SO3H, thus protecting simple steel from the corrosion of NH2SO3H.

The sulfation of ethanol lignin of abies wood by sulfamic acid–urea mixture in N,N-dimethylformamide (DMF) medium was studied for the first time. The effect of the duration of lignin sulfation process on the yield and sulfur content in resulted lignin sulfates was studied. It was shown that the reaction of ethanol lignin sulfation begins and ends in a homogeneous medium. At temperature 100 °C, the sulfur content in lignin varies from 5.4 to 6.8% mass, depending on the process time. The introduction of sulfate groups into the lignin structure was confirmed by FTIR and 2D NMR spectroscopy. It was found that both alcohol and phenolic hydroxyl groups of lignin enter the sulfation reaction. The molecular weight distribution of sulfated ethanol lignin was determined by gel permeation chromatography. The optimized method of synthesis allows to obtain sulfated ethanol lignin with low polydispersity (1.31) and narrow molecular weight distribution (3.25–3.75 kDa).

In this study, magnetic nanoparticles (Fe3O4 NPs) were employed as good support for N-piperidine sulfamic acid to prepare a novel nanocatalyst (SA-PPCA–Fe3O4 NPs). This nanocatalyst was then characterized by different techniques such as FT-IR, XRD, TGA, SEM, TEM and VSM. The catalytic activity of the SA-PPCA–Fe3O4 NPs was studied by one-pot preparation of pyrimido[4,5-c]pyridazines derivatives from three-component reactions of 1,3-dimethylthiobarbituric acid or 1,3-diethylthiobarbituric acid with different arylglyoxals and hydrazine monohydrate at ambient conditions. SA-PPCA–Fe3O4 NPs exhibited excellent advantages such as simplicity, high yields, short reaction time, easily separation using an external magnet, bio eco-friendly and recoverability and reusability with no remarkable loss of catalytic efficiency. In this work, density functional theory and modeling were reported to investigate of mechanism of the reaction. In fact, this study gives an insight into the mechanism of the pyrimido[4,5-c]pyridazines reaction in the presence of nanocatalyst of SA-PPCA–Fe3O4 NPs.

A simple-structure zwitterion of sulfamic acid (+H3N–SO3–, SA) is introduced to construct an effective chemical bridge between SnO2 and a perovskite layer through a coordination bond via the -SO3– anion for remedying the oxygen vacancies of SnO2 and meanwhile to passivate charged defects of the perovskite through electrostatic interaction via the -NH3+ cation. The introduced SA results in high-quality perovskite films with large grain size, due to the better wettability for perovskite solution. Consequently, the SA-modified solar cell generates an enhanced efficiency from 18.2% to 20.4% with negligible hysteresis. Remarkably, the unsealed device with SA modification also exhibits considerably improved stability.

Inspired by the high-water solubility, photoluminescence and low cytotoxicity of N-doped carbon quantum dots (N-CQDs), fluorescent corrosion inhibitors with size of 4–8 nm were synthesized from disodium ethylenediaminetetraacetate, sulfamic acid, and urotropine salt. We expect that these N-CQDs may possess an excellent protective ability to inhibit the corrosion of carbon steel in aggressive solutions owing to its special functional group. The inhibitory mechanism of the inhibitor on N80 steel in saturated CO2 3 wt % NaCl solution was studied by weight loss, adsorption curve fitting, electrochemical measurement, and surface morphology and elemental analysis. The results show that corrosion of N80 carbon steel in saturated CO2 3 wt % NaCl solution is significantly inhibited by the addition of N-CQDs, which is attributed to the formation of its adsorption film, preventing the contact of iron with chloride ions and is an effective corrosion inhibitor.

The new process of abies ethanol lignin sulfation by a low-toxic mixture of sulfamic acid and urea in 1,4-dioxane medium was optimized, and the structure of sulfated ethanol lignin was studied. The process of lignin sulfation is described by a first-order equation in the temperature range 70–100 °C. The value of the rate constants is weakly dependent on the ratios of lignin and sulfating complex (sulfamic acid–urea mixture). The activation energy of the sulfation process decreases from 11.5 to 7.5 kJ/mol with an increase in the content of the sulfating complex (SC). The optimal conditions for sulfation of abies ethanol lignin with a high yield of water-soluble sulfated lignin [(100% of mass) with sulfur content of 7.9%] were found: temperature 95–100 °C, L/SC ratio 1:2.3–1:2.9, time 2 h. The composition and structure of water-soluble sulfated ethanol lignin were determined by elemental analysis, FTIR spectroscopy, two-dimensional NMR spectroscopy and gel permeation chromatography. It was shown that only alcoholic OH groups of ethanol lignin react with sulfamic acid. Sulfated ethanol lignin has a higher molecular weight and a lower degree of polydispersity compared to the initial ethanol lignin.

Protection techniques of functional groups within the structure of organic compounds are important synthetic methods against unwanted attacks from various reagents during synthetic sequences. Acetal and thioacetal groups are well known as protective functional groups in organic reactions. In this study, acetalization of carbonyl compounds with diols and dithiols and methoxymethylation of alcohols with formaldehyde dimethyl acetal (FDMA) have been carried out using sulfamic acid-functionalized magnetic Fe3O4 nanoparticles (SA-MNPs) as a heterogeneous solid acid catalyst. Products were characterized by FT-IR and NMR spectroscopies. The structural and electronic properties of some products were computed by quantum mechanical (QM) methods. Depending on the stereochemistry and electronic properties that were obtained by computational results, we have suggested that hyperconjugation plays a key role in the structural properties of 2-phenyl-1,3-dioxolane derivatives, and also the electron transfer between π-electrons of the aromatic ring with the 3d orbital of S-atoms influences the 2-phenyl-1,3-dithiane derivatives' structure.

В настоящей статье изложены результаты электрохимического растворения Sn-Pb сплава в электролитах на основе сульфаминовой кислоты, проводимого в гальваностатическом режиме при различных значениях плотностей тока. Показано, что в диапазоне исследуемых плотностей тока 0,10-0,25 А/см2 скорость растворения сплава зависит от состава электролита – добавка азотной кислоты увеличивает скорость растворения в 1,8 раза, снижение концентрации сульфаминовой кислоты в 2 раза ведет к снижению скорости растворения в 1,3 раза. Установлено, что в при проведении процесса электрохимического растворения Sn-Pb сплава в гальваностатическом режиме при плотностях тока 0,10-0,25 А/см2 катодный осадок имеет состав (масс.% ): свинец – 99,4-99,6; олово – 0,4-0,6., This article presents the results of electrochemical dissolution of Sn-Pb alloy in electrolytes based on sulfamic acid, conducted in galvanostatic mode at different values of current densities. It is shown that in the range of the studied current densities of 0,10-0,25 A/cm2, the dissolution rate of the alloy depends on the composition of the electrolyte – the addition of nitric acid increases the dissolution rate by 1,8 times, a decrease in the concentration of sulfamic acid by 2 times leads to a decrease in the dissolution rate by 1,3 times. It was found that during the electrochemical dissolution of the Sn-Pb alloy in galvanostatic mode at current densities of 0,10-0,25 A/cm2, the cathode precipitate has the composition (mass%): lead – 99,4-99,6; tin – 0,4-0,6., Горный журнал Казахстана, Выпуск 9 (209) 2022, Pages 34-39

The IR spectra and molecular mass distribution of arabinogalactan sulfates in the form of sodium and ammonium salts, obtained using various sulfating reagents, were compared. According to the obtained data, the sulfated derivatives of arabinogalactan differ from each other by the nature of the hydrogen bonds and the molecular weight distribution. Using coagulological tests at the activation of coagulation of platelet-poor human plasma, in vitro study of the anticoagulant properties of arabinogalactan sulfated derivatives in various salt forms differing in methods of preparation, degree of sulfation and molecular weight was conducted. It was established that the sample in the form of arabinogalactan sodium salt (SAG 1) with a sulfur content of 13.2 wt.% аnd a polydispersity degree of 1.52 showed 2 times more anticoagulant activity than the sample in the form of ammonium salt of arabinogalactan (SAG 2) with the sulfur content of 6.6 wt.% and the degree of polydispersity of 1.30. Antithrombin (aIIa) activity of samples obtained by sulfation with pyridine and sulfuric anhydride complex (SAG 1) and sulfamic acid complex (SAG 2) was, respectively, 23.42±1.86 and 10.20±1.50 U/mg; the anti-factor Xa activity of SAG 1 and SAG 2 was 2.13±0.42 and 0.37±0.08 U/mg; and the ratio aIIa/aXa for SAG1 and SAG 2 was 11 and 28, respectively. The less activity of antifactor Xa(aXA) of SAG as compared to unfractionated heparin (UFG) and higher rations of activities aIIa/aXa may contribute the less provocation of bleeding by SAG samples in the comparition with UFG.

Most part of all additives to technological fluids for acid treatments of oil-extracting wells are surfactants. One of approaches to assess the behavior of surfactants in these compositions is to determine the interfacial tension of their solutions at the interface with hydrocarbons. The interfacial tension of surfactant—acid compositions based on hydrochloric and sulfamic acids and also on distilled water without addition of acids. The interfacial tension was determined at the boundary with n-octane, kerosene, and oil with different polarities and contents of natural surfactants. It was shown that n-octane and kerosene are model systems that allow conditional comparison in activity between surfactants. A dependence was found of the interfacial tension of a surfactant—acid formulations on the nature of an acid: sulfamic acid affects the activity of surfactants positively, and hydrochloric acid, negatively. The interfacial tension parameter being determined is strongly affected by the type of a surfactant. It was shown that the nonionogenic surfactant Neonol AF 9–12 shows the smallest values of the interfacial tension in the formulations based on distilled water, and the anionic surfactant Nezhegol, in acid formulations, which is due to the interaction of the functional group of a surfactant with hydroxonium ions present in solution.

A simple, efficient and eco-friendly method for the synthesis of 1,2-dihydroquinazolines has been developed using three-component reaction of readily available aromatic aldehydes, 2-aminobenzophenones, ammonium acetate with sulfamic acid as a green and recyclable catalyst. The significant features of this method include short reaction time, operational simplicity, high yields and high selectivity. Interestingly, the catalyst can be recovered and reused for up to four cycles without any loss in catalytic activity. By employing this method, a series of 23 compounds was synthesized and tested for antimicrobial activity against both Gram-positive and Gram-negative bacterial strains as well as a fungal strain. Among these, compounds 4l, 4v and 4w showed appreciable antibacterial activity selectively against Gram-positive bacteria, wherein compound 4w exhibited promising antibacterial activity with MIC value of 0.010 μMol L−1 against Staphylococcus aureus MTCC 96 and Micrococcus luteus MTCC 2470. In addition, 4w also showed promising bactericidal and biofilm formation inhibitory effects. Keywords: 1,2-Dihydroquinazolines, Sulfamic acid, Recyclability, Antimicrobial, Anti-biofilm

A new sulfamic acid-based formulation is developed for the effective chemical cleaning of modified 9Cr–1Mo steel as a replacement for the conventional corrosive nitric acid (HNO3) and hydrofluoric acid (HF) mixture. The effect of sulfamic acid concentrations and inhibitor (2-mercaptobenzimidazole, MBI) on the metal loss during cleaning of modified 9Cr–1Mo steel was studied using weight loss and electrochemical impedance spectroscopic methods. The metal loss was found to increase with increase in acid concentration, but it was significantly lower with increasing inhibitor concentration, with an efficiency of > 90%. The corrosion rates of modified 9Cr–1Mo steel with 10% sulfamic acid + 2 mM MBI, 10% sulfamic acid without inhibitor and HNO3 + HF mixture were 1290, 6426, and 303,515 μm year−1 respectively. The optimal composition for efficient cleaning, with least base metal loss, was found to be 10% sulfamic acid + 2 mM MBI. Laser Raman spectroscopic (LRS) analysis of the corrosion products obtained during chemical cleaning process revealed that a protective chromium oxide film was formed during the cleaning with sulfamic acid + inhibitor as compared to iron oxide-based films with HNO3 + HF mixture and 10% sulfamic acid solutions.

Acid treatments are one of the methods for intensifying oil and gas production. Corrosion is a significant factor affecting the performance of oilfield equipment. There are many different methods of preventing corrosion, but corrosion inhibitors are most commonly used in industry. The protective effect of the inhibitor is directly determined by the effective adsorption of surfactants on the metal surface. For an indirect assessment of the adsorption of the inhibitor, a comprehensive research method is proposed based on the determination of the interfacial tension of acid compositions and steel plates’ contact angle of wetting after corrosion tests. It was found that in hydrochloric acid the adsorption of the inhibitor IC-1 reaches a maximum after 6 h, an increase in the acid concentration in the range of 5–15% wt. has a negative effect on the activity of the inhibitor. For sulfamic acid, the maximum adsorption of the IC-2 inhibitor is observed after 24 h, an increase in acid concentration has a positive effect on surfactants.

Due to unexpected Pu behavior using the U/TEVA resin and the most-recognized reagents, some key separation stages need to be studied for the U–Pu separation: Pu valency adjustment, Pu elution solution composition, resin loading rate and Pu elution solution stability over time. The new Pu elution solution developped in the study, composed of 3 × 10–3 mol L−1 ascorbic acid / 3 × 10–3 mol L−1 sulfamic acid / 2 mol L−1 HNO3, helps obtaining a more robust method: recovery yields over 80% and decontamination factor up to 2 × 104. The best separation performances were obtained when the new Pu elution solution was freshly prepared, the resin loading rate did not exceed 30% and with a waiting time for the valency adjustment between the addition of H2O2 and the start of the chromatographic cycle set at 42 h regardless the Pu quantity involved.

A new, simple and cost-effective method for the synthesis of sulfated beta-cyclodextrin (S-β-CD), one of the most widely used chiral mobile phase additive, using sulfamic acid as sulfonating agent has been described. The method was optimized and the acquired product was characterized and compared with a marketed Sigma Aldrich sulfated beta-cyclodextrin (S-β-CD1). Beta cyclodextrin (β-CD), hydroxypropyl beta-cyclodextrin (HP-β-CD), S-β-CD1 and S-β-CD2 were evaluated as chiral mobile phase additives (CMPAs) for the enantiomeric separation of cloperastine, an antitussive agent, using reversed-phase HPLC. Under the optimized conditions, a resolution of 3.14 was achieved within 15 minutes on an achiral Kromasil C8 (150 x 4.6 mm, 5 µ) column with a mobile phase of 5mM monopotassium phosphate containing 10mM S-β-CD3 pH 3 and 45% methanol with a run time of 15 min. The method utilizing S-β-CD3 as CMPA was validated as per ICH guidelines and applied for the quantitative determination of cloperastine enantiomers in active pharmaceutical ingredients and pharmaceutical formulations. The selectivity changes imparted by S-β-CD were proven to be beneficial for chiral separation. The chiral recognition mechanism and elution order of the reported enantiomers were determined by simulation studies. It was observed that inclusion complex formation and hydrogen bonding are the major forces for the chiral resolution.