Physical-chemical Properties of Substituted Amides in Aqueous Solution and Evaluation of Their Potential Use as Solubilizing Agents

1973 ◽  
Vol 62 (8) ◽  
pp. 1320-1327 ◽  
Author(s):  
Patrick P. Deluca ◽  
Leon Lachman ◽  
Hans G. Schroeder
RSC Advances ◽  
2017 ◽  
Vol 7 (87) ◽  
pp. 54969-54979 ◽  
Author(s):  
Dezhi Chen ◽  
Shasha Xie ◽  
Caiqin Chen ◽  
Hongying Quan ◽  
Li Hua ◽  
...  

In recent years, the application of biochar to remove contaminants from aqueous solutions has become interesting due to favorable physical/chemical properties and abundant feedstocks.


1979 ◽  
Vol 179 (3) ◽  
pp. 675-689 ◽  
Author(s):  
M C Carey ◽  
A P Koretsky

Spectrophotometric measurements of bilirubin-IX alpha in water and in aqueous/organic solvent mixtures at pH 10.0 as a function of bilirubin-IX alpha concentration (approx. 0.6–400 microM) are consistent with the formation of dimers (KD - 1.5 microM) in dilute (less than 10 microM) aqueous solution and further self-aggregation to multimers at higher concentrations. Added urea (to 10M) and increases in temperature (to 62 degrees C) obliterate the dimer-multimer transition at 10 microM, but added NaCl (to 0.30 M) promotes strong aggregation of dimers over a narrow concentration range, suggesting a ‘micellization’ phenomenon. Concentrations of dioxan or ethanol greater than 60% (v/v) in water were required to obtain the absorption spectrum of bilirubin-IX alpha monomers, suggesting that both hydrophobic and electrostatic (pi-orbital) interactions are involved in stabilizing the dimeric state in water. Micellar concentrations of sodium dodecyl sulphate induced spectrophotometric shifts in the dimer absorption spectrum of bilirubin-IX alpha consistent with progressive partitioning of bilirubin-IX alpha monomers into a relatively non-polar region of the micelles and allowed a deduction of the apparent critical micellar concentration that closely approximated the literature values. The pattern of bilirubin IX alpha association with bile salts is complex, since the absorption spectrum shifts hypsochromically below and bathochromically above the critical micellar concentration of the bile salts. Consistent with these observations, bilirubin IX alpha appears to bind to the polar face of bile salt monomers and to the polar perimeter of small bile salt micelles. At higher bile salt concentrations some-bilirubin-IX alpha monomers partition into the hydrophobic interior of the bile salt micelles. Our results suggest that under physiological conditions the natural conjugates of bilirubin-IX alpha may exhibit similar physical chemical properties in bile, in that dimers, highly aggregated multimers and bile salt-associated monomers may co-exist.


1986 ◽  
Vol 21 (3) ◽  
pp. 344-350 ◽  
Author(s):  
Barry G. Oliver ◽  
Klaus L.E. Kaiser

Abstract The concent rat ions of hexachloroethane (HCE), hexachlorobutadiene (HCBD), pentachlorobenzene (QCB), hexachlorobenzene (HCB) and octachlorostyrene (OCS) in large volume water samples show that the major sources of these chemicals to the St. Clair River are Dow Chemical Company effluents and, to a lesser degree, Sarnia’s Township ditch which drains one of Dow’s waste disposal sites. Tributaries entering the river on both sides of the Canada/United States border contain measurable concentrations of these chemicals indicating low level contamination throughout the area. The degree of water/suspended sediment partitioning of the chemicals (Kp) was studied. Kp values for the individual chemicals changed in a manner consistent with changes in their physical-chemical properties.


2020 ◽  
Vol 20 (11) ◽  
pp. 1340-1351 ◽  
Author(s):  
Ponnurengam M. Sivakumar ◽  
Matin Islami ◽  
Ali Zarrabi ◽  
Arezoo Khosravi ◽  
Shohreh Peimanfard

Background and objective: Graphene-based nanomaterials have received increasing attention due to their unique physical-chemical properties including two-dimensional planar structure, large surface area, chemical and mechanical stability, superconductivity and good biocompatibility. On the other hand, graphene-based nanomaterials have been explored as theranostics agents, the combination of therapeutics and diagnostics. In recent years, grafting hydrophilic polymer moieties have been introduced as an efficient approach to improve the properties of graphene-based nanomaterials and obtain new nanoassemblies for cancer therapy. Methods and results: This review would illustrate biodistribution, cellular uptake and toxicity of polymergraphene nanoassemblies and summarize part of successes achieved in cancer treatment using such nanoassemblies. Conclusion: The observations showed successful targeting functionality of the polymer-GO conjugations and demonstrated a reduction of the side effects of anti-cancer drugs for normal tissues.


Molecules ◽  
2021 ◽  
Vol 26 (4) ◽  
pp. 1026 ◽  
Author(s):  
Laís G. Fregolente ◽  
João Vitor dos Santos ◽  
Giovanni Vinci ◽  
Alessandro Piccolo ◽  
Altair B. Moreira ◽  
...  

Hydrochar is a carbon-based material that can be used as soil amendment. Since the physical-chemical properties of hydrochar are mainly assigned to process parameters, we aimed at evaluating the organic fraction of different hydrochars through 13C-NMR and off-line TMAH-GC/MS. Four hydrochars produced with sugarcane bagasse, vinasse and sulfuric or phosphoric acids were analyzed to elucidate the main molecular features. Germination and initial growth of maize seedlings were assessed using hydrochar water-soluble fraction to evaluate their potential use as growth promoters. The hydrochars prepared with phosphoric acid showed larger amounts of bioavailable lignin-derived structures. Although no differences were shown about the percentage of maize seeds germination, the hydrochar produced with phosphoric acid promoted a better seedling growth. For this sample, the greatest relative percentage of benzene derivatives and phenolic compounds were associated to hormone-like effects, responsible for stimulating shoot and root elongation. The reactions parameters proved to be determinant for the organic composition of hydrochar, exerting a strict influence on molecular features and plant growth response.


2021 ◽  
Vol 11 (10) ◽  
pp. 4417
Author(s):  
Veronica Vendramin ◽  
Gaia Spinato ◽  
Simone Vincenzi

Chitosan is a chitin-derived fiber, extracted from the shellfish shells, a by-product of the fish industry, or from fungi grown in bioreactors. In oenology, it is used for the control of Brettanomyces spp., for the prevention of ferric, copper, and protein casse and for clarification. The International Organisation of Vine and Wine established the exclusive utilization of fungal chitosan to avoid the eventuality of allergic reactions. This work focuses on the differences between two chitosan categories, fungal and animal chitosan, characterizing several samples in terms of chitin content and degree of deacetylation. In addition, different acids were used to dissolve chitosans, and their effect on viscosity and on the efficacy in wine clarification were observed. The results demonstrated that even if fungal and animal chitosans shared similar chemical properties (deacetylation degree and chitin content), they showed different viscosity depending on their molecular weight but also on the acid used to dissolve them. A significant difference was discovered on their fining properties, as animal chitosans showed a faster and greater sedimentation compared to the fungal ones, independently from the acid used for their dissolution. This suggests that physical–chemical differences in the molecular structure occur between the two chitosan categories and that this significantly affects their technologic (oenological) properties.


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