Demineralization in organic solvents by alkylammonium salts of ethylenediaminetetra-acetic acid.
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ABSTRACT:
SUBMITTER: Scott JE
PROVIDER: S-EPMC1183843 | biostudies-other | 1978 Mar
REPOSITORIES: biostudies-other
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Project description:In the current study, two organic salts (1 and 2) are synthesized, and then crystalline structures are characterized by FTIR, UV spectroscopy, and X-ray crystallographic studies. The organic salts 1 and 2 are optimized at the M06/6-311G(d,p)level of theory and further utilized for analysis of natural bond orbitals (NBOs), natural population, frontier molecular orbitals (FMOs), and global reactivity parameters, which confirmed the stability of the studied compounds and charge transfer phenomenon in the studied compounds. The studies further revealed that 1 and 2 are more stable than 3. The lowest energy merged monomer-coformer conformations were docked as flexible ligands with rigid fungal proteins and DNA receptors. The stagnant binding of the monomer through two H bonds with protein was observed for ligands 1 and 3 while different pattern was found with 2. The coformers formed a single H bond with the active site in 2 and 3 and a single pi-arene H interaction in 1. The two-point ligand-receptor interactions hooked the monomer between DNA base pairs for partial intercalation; pi stacking with additive hydrogen bonding with the base pair led to a strong benzimidazole interaction in 1 and 2, whereas ethylene diamine formed weak H bonding. Thus, the molecular docking predicted that the coformer exhibited DNA intercalation reinforced by its salt formation with benzimidazole 1 and methyl benzimidazole 2. Antioxidant studies depicted that 3 has a higher IC50 value than that of 2,4-D and also the largest value among the studied compounds, whereas 2 showed the lowest value among the studied compounds.
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Project description:This study considers the kinetics of snail shells demineralization process using acetic acid. It was washed, sundried then ground into four different particle sizes. The ranges of particle sizes are 6.3-4.75 mm, 4.75-2 mm, 2 - 1 mm, and 600 -300 ?m. The shells were first deproteinized with sodium hydroxide solution thereafter they were demineralized using 1.2 M acetic acid solution. Kinetics of demineralization of the snail shells was performed by XRF analysis of the chitin produced at 5, 10, 15, 20, 25, 30, and 35 min. The kinetic results show that mechanism of chitin formation from snail shell occurs through the chemical reaction controlled (CRC) model of the shrinking core model for particle sizes between 6.3 - 4.75 mm, 4.75-2 mm, and 2-1 mm particle sizes while Fluid Film Diffusion (FFD) model was observed for the smaller range of 600-300 ?m particle sizes. The surface morphology and the FTIR analysis of the synthesized chitin were typical of those obtained for earlier studies.
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Project description:The structures of the ammonium salts of phen-oxy-acetic acid, NH4 (+)·C8H6O3 (-), (I), (4-fluoro-phen-oxy)acetic acid, NH4 (+)·C8H5FO3 (-), (II), and the herbicidally active (4-chloro-2-methyl-phen-oxy)acetic acid (MCPA), NH4 (+)·C9H8ClO3 (-)·0.5H2O, (III) have been determined. All have two-dimensional layered structures based on inter-species ammonium N-H?O hydrogen-bonding associations, which give core substructures consisting primarily of conjoined cyclic motifs. The crystals of (I) and (II) are isomorphous with the core comprising R 1 (2)(5), R 1 (2)(4) and centrosymmetric R 4 (2)(8) ring motifs, giving two-dimensional layers lying parallel to (100). In (III), the water mol-ecule of solvation lies on a crystallographic twofold rotation axis and bridges two carboxyl O atoms in an R 4 (4)(12) hydrogen-bonded motif, creating two R 4 (3)(10) rings, which together with a conjoined centrosymmetric R 4 (2)(8) ring incorporating both ammonium cations, generate two-dimensional layers lying parallel to (100). No ?-? ring associations are present in any of the structures.
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Project description:Current aquatic chemical testing guidelines recognise that solvents can potentially interfere with the organism or environmental conditions of aquatic ecotoxicity tests and therefore recommend concentration limits for their use. These recommendations are based on evidence of adverse solvent effects in apical level tests. The growing importance of sub-apical and chronic endpoints in future test strategies, however, suggests the limits may need re-assessment. To address this concern, microarrays were used to determine the effects of organic solvents, dimethylformamide (DMF) and dimethyl sulfoxide (DMSO), upon the transcriptome of zebrafish (Danio rerio) embryos. Embryos were exposed for 48 h to 0.025 and 0.1 ml/L DMF or DMSO. Effects on survival and development after 24 and 48 h were assessed microscopically with no effects on mortality or morphology. However, analysis of 48-h embryonic RNA revealed large numbers of differentially expressed genes for both solvent at both concentrations. The enrichment of differentially expressed genes was found for metabolic, development and other key biological processes, some of which could be linked to observed morphological effects at higher solvent concentrations. These findings emphasise the need to remove or lower as far as possible, the concentrations of solvent carriers in ecotoxicology tests.
2011-10-06 | GSE32593 | GEO
Project description:Acetic acid bacteria genome sequencing and assembly
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Project description:6-Aminopenicillanic acid (6-APA) is used for synthesis of semisynthetic antibiotics. Polymer-salt aqueous two-phase systems (ATPSs) were applied for separation of 6-APA and phenyl acetic acid (PAA), as the products of hydrolyzation reaction of Penicillin G/Penicillin V. The binodal curves of ATPS composed of a copolymer (reverse Pluronic 10R5, Pluronic L35 and PEG-ran-PPG) and a salt (Tri-sodium citrate, tri-potassium citrate, di-potassium phosphate, sodium sulphate and magnesium sulphate) were obtained. The results show that, at a fixed PPG/PEG ratio, block copolymers have larger two-phase region compared with random copolymer. After screening on the partition coefficient of PAA and 6-APA separately, Na2SO4 was selected for studying the effect of the copolymer structure and the composition of salt and copolymer on partitioning, considering higher selectivity of PAA and 6-APA. 10R5-Na2SO4 ATPS was selected as the most appropriate system for separation of 6-APA and PAA. This system was used for separation of mixture of 6-APA and PAA. The results show that selectivity was [Formula: see text] 53 and smaller in a system, containing a mixture of 6-APA and PAA. This observation can be justified by the interaction between 6-APA and PAA. Molecular interaction between these two molecules were investigated by the Flory-Huggins interaction parameter.
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Project description:The anhydrous salts morpholinium (tetra-hydro-2-H-1,4-oxazin-4-ium) phen-oxy-acetate, C4H10NO(+)·C8H7O3 (-), (I), morpholinium (4-fluoro-phen-oxy)acetate, C4H10NO(+)·C8H6?FO3 (-), (II), and isomeric morpholinium (3,5-di-chloro-phen-oxy)acetate (3,5-D), (III), and morpholinium (2,4-di-chloro-phen-oxy)acetic acid (2,4-D), C4H10NO(+)·C8H5Cl2O3 (-), (IV), have been determined and their hydrogen-bonded structures are described. In the crystals of (I), (III) and (IV), one of the the aminium H atoms is involved in a three-centre asymmetric cation-anion N-H?O,O' R 1 (2)(4) hydrogen-bonding inter-action with the two carboxyl O-atom acceptors of the anion. With the structure of (II), the primary N-H?O inter-action is linear. In the structures of (I), (II) and (III), the second N-H?Ocarbox-yl hydrogen bond generates one-dimensional chain structures extending in all cases along [100]. With (IV), the ion pairs are linked though inversion-related N-H?O hydrogen bonds [graph set R 4 (2)(8)], giving a cyclic hetero-tetra-meric structure.
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Project description:Tolfenamic acid (TA) is a non-steroidal anti-inflammatory drug that was studied for its photodegradation in aqueous (pH 2.0-12.0) and organic solvents (acetonitrile, methanol, ethanol, 1-propanol, 1-butanol). TA follows first-order kinetics for its photodegradation, and the apparent first-order rate constants (k obs) are in the range of 0.65 (pH 12.0) to 6.94 × 10-2 (pH 3.0) min-1 in aqueous solution and 3.28 (1-butanol) to 7.69 × 10-4 (acetonitrile) min-1 in organic solvents. The rate-pH profile for TA photodegradation is an inverted V (∧) or V-top shape, indicating that the cationic form is more susceptible to acid hydrolysis than the anionic form of TA, which is less susceptible to alkaline hydrolysis. The fluorescence behavior of TA also exhibits a V-top-shaped curve, indicating maximum fluorescence intensity at pH 3.0. TA is highly stable at a pH range of 5.0-7.0, making it suitable for formulation development. In organic solvents, the photodegradation rate of TA increases with the solvent's dielectric constant and solvent acceptor number, indicating solute-solvent interactions. The values of k obs decreased with increased viscosity of the solvents due to diffusion-controlled processes. The correlation between k obs versus ionization potential and solvent density has also been established. A total of 17 photoproducts have been identified through LC-MS, of which nine have been reported for the first time. It has been confirmed through electron spin resonance (ESR) spectrometry that the excited singlet state of TA is converted into an excited triplet state through intersystem crossing, which results in an increased rate of photodegradation in acetonitrile.
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Project description:Current aquatic chemical testing guidelines recognise that solvents can potentially interfere with the organism or environmental conditions of aquatic ecotoxicity tests and therefore recommend concentration limits for their use. These recommendations are based on evidence of adverse solvent effects in apical level tests. The growing importance of sub-apical and chronic endpoints in future test strategies, however, suggests the limits may need re-assessment. To address this concern, microarrays were used to determine the effects of organic solvents, dimethylformamide (DMF) and dimethyl sulfoxide (DMSO), upon the transcriptome of zebrafish (Danio rerio) embryos. Embryos were exposed for 48 h to 0.025 and 0.1 ml/L DMF or DMSO. Effects on survival and development after 24 and 48 h were assessed microscopically with no effects on mortality or morphology. However, analysis of 48-h embryonic RNA revealed large numbers of differentially expressed genes for both solvent at both concentrations. The enrichment of differentially expressed genes was found for metabolic, development and other key biological processes, some of which could be linked to observed morphological effects at higher solvent concentrations. These findings emphasise the need to remove or lower as far as possible, the concentrations of solvent carriers in ecotoxicology tests. Balanced loop design consisting of five separate conditions - two exposure concentrations for each of the two solvents and a control treatment - using four replicates for each condition all of which were dye swapped, resulting in a total of twenty independant samples on twenty arrays.
2011-10-05 | E-GEOD-32593 | biostudies-arrayexpress