Sulfamic Acids Research Articles

Sulfamates and methanesulfonates of l-arginine and l-histidine

Reactions of l-arginine (L-Arg) and l-histidine (L-His) with sulfamic (NH2SO3H) and methanesulfonic (CH3SO3H) acids in aqueous media were investigated. The following salts (L-ArgH)(NH2SO3) (I), (L-ArgH)(CH3SO3) (II), (L-ArgH2)(CH3SO3)2 (III), (L-HisH)(NH2SO3) (IV), (L-HisH2)(NH2SO3)2 (V), (L-HisH)(CH3SO3).2H2O (VI), (L-HisH2)(CH3SO3)2 (VII) were obtained and characterized structurally and by vibrational spectroscopy. Large crystals of (II), (VI), (VII) were grown from aqueous solution by evaporation method. The crystal (IV) was known previously and characterized spectroscopically, however, the published infrared spectrum significantly differs from our spectrum.

Comparative Laboratory Tests of Methanesulfonate and Sulfamic Tinplate Tinning Electrolytes

Comparative tests are performed under laboratory conditions in units modeling existing electrolytic tinning units for contemporary ecologically clean tinning electrolytes based on methanesulfonate (Niveostan 200 version) and sulfamic acids. The main comparison criteria are: adaptability (the range of tolerance for the main parameters); hydrolysis stability and the level of sludge formation; tinned coating qualitative properties. It is shown that both types of electrolytes meet the specifications laid down for tinplate industrial tinning electrolytes and make it possible to prepare high quality anticorrosion coatings over a wide temperature range from 30 to 60°C, and they may provide good electrolytic efficiency (tin current efficiency 95%) with sensible limitation of the current density limit. Sulfamic electrolyte provides a broader range of variation in current density. Methanesulfonate electrolyte without admixture of iron is hardly prone to sludge formation. With an identical iron content (10 g/liter), both electrolytes have about the same low level of tin loss in sludge, but the anticipated rate of iron accumulation is greater in methanesulfonate electrolyte. The main advantage of methanesulfonate tinning is the high electrolyte electrical conductivity making it possible to reduce electrical energy consumption. Maximum use of the technical possibilities of both types of electrolyte is possible in new tinning lines planned and constructed in accordance with features of the production processes used.

DESTRUCTION OF RESINOUS COMPOUND FROM WASTE BY USE OF NATURAL ENZYMES

In present scenario huge quantity of waste are produced every day. It contains plastics, waste papers, plastic containers, some of these are degradable, and some of these are non-degradable waste.Non-biodegradable things are present in waste treated with mechanical pulverizing mechanisms and with few of strong chemical. Chemicals such as concentrated Hydrochloric, Sulphuric acids, sulphamic acids and many other hazardous chemicals are used for destroying wastes in simple form or in disperse form. Almost 70% of the waste is being dumped in the soil layer. After certain interval of time compounds present in soils such as salts of the metals and temperature of soil help in decomposing the waste periodically. Due to this process large quantity of soil gets contaminated. In this project we have tried to replace hazardous chemicals with other non-hazardous chemicals and some natural enzymes, which may give same reactions as with toxic chemicals. Objectives may also helps in use of eco friendly chemicals for reducing soil pollution and water pollutions. Hence it will minimize the other impacts on environment such as air pollution, noise pollutions, water pollutions and soil pollutions. All process will carry out under Green Chemistry cycles.

Adhesion, Proliferation and Migration of NIH/3T3 Cells on Modified Polyaniline Surfaces.

Polyaniline shows great potential and promises wide application in the biomedical field thanks to its intrinsic conductivity and material properties, which closely resemble natural tissues. Surface properties are crucial, as these predetermine any interaction with biological fluids, proteins and cells. An advantage of polyaniline is the simple modification of its surface, e.g., by using various dopant acids. An investigation was made into the adhesion, proliferation and migration of mouse embryonic fibroblasts on pristine polyaniline films and films doped with sulfamic and phosphotungstic acids. In addition, polyaniline films supplemented with poly (2-acrylamido-2-methyl-1-propanesulfonic) acid at various ratios were tested. Results showed that the NIH/3T3 cell line was able to adhere, proliferate and migrate on the pristine polyaniline films as well as those films doped with sulfamic and phosphotungstic acids; thus, utilization of said forms in biomedicine appears promising. Nevertheless, incorporating poly (2-acrylamido-2-methyl-1-propanesulfonic) acid altered the surface properties of the polyaniline films and significantly affected cell behavior. In order to reveal the crucial factor influencing the surface/cell interaction, cell behavior is discussed in the context of the surface energy of individual samples. It was clearly demonstrated that the lesser the difference between the surface energy of the sample and cell, the more cyto-compatible the surface is.

AMINOMETHANESULPHONIC ACIDS AND ITS N-DERIVATIVES ARE COMPONENTS OF N. GOODS BUFFERS

On the basis of pH measuring the temperature dependence of the second ionization constant (pK2) are set for aminomethansulfonic acid (AMSA) and its N-derivatives. It was found that the area of effective buffering of AMSK and its N-benzyl derivative allows to maintain the pH of acid-compatible with life. The absolute values of the coefficients in the equation pK2 = -Ai+ Bi/T for the aminosulfonic acids correlated with their molar masses. A simultaneous change in values DpH /DT and Bicoefficient for the studied acids QSAR method are stayed. The values of the distribution coefficients in the octanol – water (Pow) and molar refraction are calculated. In the future the data obtained in this study will be used to predict the physical, chemical and toxicological properties of the compounds studied.

Clustering of simple aminosulfonic acids – electrospray ionization mass spectrometric study

Aminosulfonic acids are structurally related to amino acids as bifunctional compounds. Some of them like taurine and homotaurine play important roles in biology. Although there is a vast literature devoted to the electrospray ionization mass spectrometric (ESI-MS) study of amino acid aggregation, no such study has been performed so far for aminosulfonic acids. A gas-phase clustering study was performed for aminomethanesulfonic acid (AMS), taurine (Tau), homotaurine (HT), and cysteic acid (CA) from water and methanol/water solutions, using a Bruker TOF-Q spectrometer equipped with an ESI source, in the negative-ion mode. For selected anionic clusters the tandem mass (MS/MS) spectra were recorded and the breakdown curves were obtained. The cluster formation abilities (ACS parameter) of the studied molecules were calculated. Both singly and doubly charged clusters were formed when the acids were electrosprayed from water solutions; they may be described as [(H3N-R-SO3)n-zH](z-), where z = 1 or 2. The largest identified clusters are built of 20, 22, 20 and 4 monomers of AMS, Tau, HT and CA, respectively. The doubly negatively charged clusters were observed for n ≥9, 12, 14 in the case of AMS, Tau and HT. AMS pentamers and Tau, HT tetramers and hexamers show higher stabilities than the other clusters. The results indicate that aminosulfonic acids form large stable clusters, similarly to aminocarboxylic acids. The cluster formation ability decreases with an increase in CH2 chain length within the series of the studied compounds. The large singly and doubly charged aggregates are formed under the conditions of the experiment, possibly in the droplets. Taurine dissolved in water seems to be a good calibrant for electrospray instruments in negative ion mode.

Galvanic series of different stainless steels and copper- and aluminium-based materials in acid solutions

Galvanic series of AISI 304, 316, 316L, and 316Ti austenitic stainless steels, AISI 410 and 420 martensitic stainless steels, 63Cu37Zn brass, Cu, Al, and AlMg1 were established for 10% (wt.) hydrochloric, phosphoric, sulphamic, sulphuric, nitric, citric, acetic, and methanesulphonic (MSA) acids used as cleaners in order to predict galvanic corrosion when coupling these materials. It was found that each acid has a distinctive order of metallic materials in a galvanic series. The largest corrosion potential difference in all acids exists between Al-based materials and stainless steels, as well as Cu-based materials indicating the use of Al-based materials as sacrificial electrodes.

Mechanistic investigations of cinchona alkaloid-based zwitterionic chiral stationary phases

Novel zwitterionic cinchona alkaloid-based chiral selectors (SOs) were synthesized and immobilized on silica gel. The corresponding brush-type chiral stationary phases (CSPs) were characterized as zwitterionic ion-exchange-type materials and exhibited remarkable enantioselectivity for their zwitterionic target analytes, viz. underivatized amino acids and aminosulfonic acids. We rationally designed structural modifications on the strong cation exchange (SCX) subunit of the zwitterionic SO and investigated the influence on chiral recognition power for amphoteric solutes. SOs with chiral isopropyl- or cyclohexyl-moieties in vicinity to the SCX site showed broadest application range by baseline resolving 39 out of 53 test compounds, including α-, β-, and γ-amino acids with different substitution patterns. Furthermore, we introduced two pseudoenantiomeric zwitterionic CSPs which combined the unique features of providing comparable enantioselectivities but reversed enantiomer elution orders. By application of slightly acidic polar organic mobile phases as preferred elution mode, we found that certain amounts of aprotic acetonitrile in protic methanol substantially increased enantioselectivity and resolution of amino acids in a structure-dependent manner.

Electrochemical method for pickling and passivation of austenitic steel welds

The aim of this work is to develop an innovative process for pickling and passivating tungsten inert gas welds on austenitic stainless steel in order to obtain complete removal of non-protective oxides and to passivate the metal surface. In particular, the treatment intends to increase both corrosion resistance and surface appearance of the steel without making use of traditional pickling solutions (which usually contain high concentrations of strong acids). The treatment, based on an electrochemical approach, uses specific electrolytes, and to evaluate their effect in terms of corrosion resistance and surface finish, different solutions were prepared and tested using low concentrations of weak organic acids, e.g. citric, oxalic, sulphamic, gluconic and lactic acids. This aspect is very important to reduce the hazardousness of the solution compared to the traditional pickling acids.

Electrodeposition of CuGaSe<SUB>2</SUB> Layer from Solutions with Different Complexing Agents

CuGaSe$_{2}$ (CGS) thin films were deposited on ITO substrates by electrodeposition from the solutions with different acidic agents, namely hydrochloric, sulphamic and citric acids. Cyclic voltammetry (CV) studies of unitary Cu, Ga, and Se systems and ternary Cu-Ga-Se systems were carried out to determine the reduction potentials, the mechanism of deposition and the ability to deposit of each constituent. The reduction peaks were observed in all unitary systems except the case of Ga from solution with non-acid and citric acid. For the ternary systems, the voltammograms only show the peaks relating to the reduction of Cu$^{2 + }$ and Se$^{4 + }$, indicating the difficulty in deposition of Ga. The electrodepositions have been processed at - 0.6 V and - 0.95 V vs. SCE. The concentration of the films was determined by EDS. For all complexing agents, the concentration of Ga has been found to depend strongly on the deposition potential and has reached to the value of about 16{\%} at. at potential of -0.95 V from the solutions with hydrochloric and sulphamic acids.

Polyaniline–silver composites prepared by the oxidation of aniline with silver nitrate in solutions of sulfonic acids

Aniline was oxidized with silver nitrate in aqueous solutions of sulfonic acids: camphorsulfonic, methanesulfonic, sulfamic, or toluenesulfonic acids. Polyaniline–silver composites were produced slowly in 4 weeks in good yield, except for the reaction, which took place in sulfamic acid solution, where the yield was low. Polyaniline in the emeraldine form was identified with UV–visible, FTIR, and Raman spectra. Thermogravimetric analysis was used to determine the silver content, which was close to the theoretical prediction of 68.9 wt.%. Transmission electron microscopy demonstrated the presence of silver nanoparticles of ca 50 nm average sizes as the dominating species, and hairy polyaniline nanorods having diameter 150–250 nm accompanied them. The highest conductivity of 880 S cm −1 was found with the composite prepared in methanesulfonic acid solution. Its conductivity decreased with temperature increasing in the 70–315 K range, which is typical of metals such as silver. The conductivity of composites prepared in solutions of other acids was lower and increased with increasing temperature. Such dependence is typical of semiconductors, reflecting the dominating role of polyaniline in the conductivity behaviour. It is proposed that interfaces between the polyaniline matrix and dispersed silver nanoparticles play a dominating role in macroscopic level of conductivity.

Optimization of pretreatment reaction for methyl ester production from chicken fat

In biodiesel production, to use low cost feedstock such as rendered animal fats may reduce the biodiesel cost. One of the low cost animal fats is the chicken fat for biodiesel production. It is extracted from feather meal which is prepared from chicken wastes such as chicken feathers, blood, offal and trims after rendering process. However, chicken fats often contain significant amounts of FFA which cannot be converted to biodiesel using an alkaline catalyst due to the formation of soap. Therefore, the FFA level should be reduced to desired level (below 1%) by using acid catalyst before transesterification. For this aim, sulfuric, hydrochloric and sulfamic (amidosulfonic) acids were used for pretreatment reactions and the variables affecting the FFA level including alcohol molar ratio, acid catalyst amount and reaction time were investigated by using the chicken fat with 13.45% FFA. The optimum pretreatment condition was found to be 20% sulfuric acid and 40:1 methanol molar ratio based on the amount of FFA in the chicken fat for 80 min at 60 °C. After transesterification, the methyl ester yield was 87.4% and the measured fuel properties of the chicken fat methyl ester met EN 14214 and ASTM D6751 biodiesel specifications.

Effect of hydrophilicity of polyaniline particles on their electrorheology: Steady flow and dynamic behaviour

Electrorheological properties of suspensions are considerably affected by hydrophilicity of suspension particles. As a model material, polyaniline base powder protonated with sulfamic, tartaric, or perfluorooctanesulfonic acids provided particles of various hydrophilicity. The experiments revealed that, in the absence of electric field, due to a good compatibility of hydrophobic polyaniline particles with silicone-oil medium, their interactions were limited and the viscosity of suspension was low. When the electric field was applied, the rigidity of the polarized chain structure of the particles increased and, consequently, viscosity increased as well. In the contrast, the field-off suspension viscosity of highly interacting hydrophilic particles, which are incompatible with the oil, and where particle aggregation may set in, was high especially at low shear rates, and the material had a pseudoplastic character. Then, a relative increase in viscosity due to the polarization of the particles or their clusters in the electric field was much lower than in the former case. Due to a different primary structure of suspension, depending on the particle compatibility with the oil the field-off storage modulus of suspensions of hydrophobic particles was lower than the loss modulus, while in suspensions of hydrophilic particles the former modulus dominated. In both cases, an increase in elasticity with increasing electric field strength was higher than that in viscosity.

Efficient synthesis of phosphorus-containing dendrimers capped with isosteric functions of amino-bismethylene phosphonic acids

An efficient synthetic strategy to synthesize phosphorus-containing dendrimers capped with isosteric acid functions derived from tyramine is described. The method is demonstrated on a first generation dendrimer that can be easily capped with 12 amino(bismethylene) sulfonic acids and amino(bismethylene) carboxylic acids that are strict analogs of the corresponding amino(bismethylene) phosphonic acids.

Interaction of biological buffers with electrolytes: Densities of aqueous solutions of two substituted aminosulfonic acids and ionic salts from T = (298.15 to 328.15) K

Biological buffers are of utmost importance for research in biological and clinical chemistry and in oceanography, but they may not be inert enough, thus interfering with the system under study. The N-[Tris(hydroxymethyl)methyl]-3-aminopropanesulfonic acid (TAPS) and N-[Tris(hydroxymethyl)methyl]-3-amino-2-hydroxypropanesulfonic acid (TAPSO) are useful zwitterionic buffers for pH control as standard buffers in the physiological region of pH 7.7 to 9.1 for TAPS and 7.0 to 8.2 for TAPSO, respectively. In this work, interaction between these zwitterionic compounds and electrolytes of potassium acetate (KAc), potassium bromide (KBr), potassium chloride (KCl), and sodium chloride (NaCl) were investigated through measuring the densities of these buffers in aqueous and in aqueous electrolyte solutions by a high precision vibrating tube digital densitometer from T = (298.15 to 328.15) K under atmospheric pressure. In this series of measurements, the aqueous samples were prepared with various concentrations of the zwitterionic buffers, up to saturated conditions, and over salt concentrations from (1 to 4) mol · dm −3. The measured densities served to evaluate the cubic expansion coefficients, α( m, T) and the apparent molar volumes, V ϕ ( m, T). An empirical equation was used to correlate quantitatively the experimental densities over the entire concentration ranges.

1,2,3,4-Tetrahydroisoquinolinyl sulfamic acids as phosphatase PTP1B inhibitors

High-throughput screening of the P&GP corporate repository against several protein tyrosine phosphatases identified the sulfamic acid moiety as potential phosphotyrosine mimetic. Incorporation of the sulfamic acid onto a 1,2,3,4-tetrahydroisoquinoline scaffold provided a promising starting point for PTP1B inhibitor design.

MAKING SENSE OF SWEETNESS

AMONG THE FIVE SENSES, taste is probably the least understood. A new model of the human sweet-taste receptor now explains why diverse molecules, large and small, taste sweet and why sweet tastes are often additive. The model was created by chemistry professor Piero A. Temussi of the University of Naples and coworkers ( F. Med. Chem. 2005 , 48,5520 ). If confirmed, it could aid the rational design of new sweeteners and lead to better treatments for diseases linked to sugar consumption (such as diabetes and obesity). For decades, most researchers believed there had to be multiple receptors for sweet taste, comments professor of biochemistry and molecular biology D. Eric Walters of Rosalind Franklin University of Medicine & Science, North Chicago, a specialist in computer modeling and sweet-taste transduction. Sugars, amino acids, peptides, proteins, terpenes, heterocycles like saccharin, sulfamic acids, ureas, guanidines, and dozens of other classes of compounds taste sweet, and it ...

Comparison of the Effect of Different pH Buffering Techniques on the Toxicity of Copper and Zinc to Daphnia Magna and Pseudokirchneriella Subcapitata

During the time-course of ecotoxicity tests with algae and chronic (reproductive) toxicity tests with daphnids, in which algae are present as a food source, pH can dramatically increase due to photosynthetic activity. As pH changes can significantly affect metal speciation and thus its bioavailability, it may be necessary to buffer the pH of the exposure medium. One class of buffers (Good's N-subtituted aminosulfonic acids) are increasingly being used in biological and chemical applications, including ecotoxicity testing. However, the potential effect of these buffers on metal toxicity has, so far, scarcely been examined. In this study we investigated if MOPS (3-N morpholino propane sulfonic acid) affected the toxicity of copper and zinc to two standard test organisms: the cladoceran Daphnia magna and the green alga Pseudokirchneriella subcapitata. First, we demonstrate that up to a concentration of 750 mg l(-1) (which proved to be sufficient for pH buffering) MOPS did not affect 21-day net reproduction of D. magna or the 72-h population growth of P. subcapitata. Second, we conducted bioassays in copper and zinc spiked standard media for the pH range 6-8. For D. magna the possible effect of 750 mg l(-1) MOPS on acute copper and zinc toxicity was investigated by performing parallel 48-h toxicity tests in NaHCO3 and MOPS buffered test media. Seventy-two hour growth inhibition assays with P. subcapitata were performed in parallel in MOPS and NaHCO3 buffered test media and in test media with daily manual pH adjustment with HCl. For daphnids no significant differences in copper and zinc toxicity were observed between MOPS or NaHCO3 buffered test media. For algae no significant differences in metal toxicity were observed between MOPS and HCl buffered media, but in test media buffered with NaHCO3 an increased copper and zinc toxicity was observed as a consequence of pH increases during the test. Clearly, the results of this study demonstrate the importance of pH buffering in metal toxicity testing and the suitability of the MOPS buffer for that purpose.

Microgravimetric Study of Electrochemically Controlled Nucleophilic Addition of Sulfite to Polyaniline

The sulfonation of polyaniline (PANI) films by nucleophilic addition of sulfite ion has been controlled through the polymer oxidation state under electrochemical control. The process was monitored by in situ electrochemical quartz crystal microbalance (EQCM), and the polymer oxidation was accomplished by electrode potential steps in sulfite aqueous solutions. The nucleophilic addition of sulfite to PANI only takes place on the oxidized polymer. From the ratio of added mass to the injected charge, the degree of sulfonation has been obtained with a yield as high as 50%. It has been observed that the ion-exchange mechanism during the oxidation-reduction process in the resulting sulfonated polymer is analogous to the polymer produced by electrophilic sulfonation of polyaniline or by copolymerization of aniline with aminosulfonic acids, unlike the ionic exchange observed for unmodified PANI.

Is the negative charge on RNHSO3-M+ an essential requirement for sulfamate sweetness?

Although many structure-taste studies have been carried out on sulfamate (cyclamate) sweeteners, there are still some unanswered questions-notably whether the sulfamate anion, -NHSO(3)(-), is essential for sweetness in this class of compounds. The literature is contradictory on this point; therefore, 14 sulfamate esters RNHSO(3)R', which contain the sulfamate moiety but without the negative charge, i.e., -NHSO(3)(-), have been synthesized and tasted under standard conditions. Almost all of the esters were found to possess strong sweetness accompanied by bitterness. Because the esters had to be heated in water to 60 degrees C to dissolve them, it was necessary to check for partial hydrolysis to the free sulfamic acids, RNHSO(3)H, since they would be sweet and would invalidate the tasting results if formed. This was done by monitoring (gas-liquid chromatography) the formation of alcohol after heating. Negligible or very low hydrolysis to acid was found for all 14 esters. This work, in addition to answering an important structure-taste question, points the way to the potential use of suitable sulfamate esters as additives in situations where the more usual sodium sulfamate salts are unsuitable, for example, in hydrophobic media.