Diffusion in aqueous nitric acid solutions

Speciation in aqueous solutions of nitric acid.

In this study, speciation in aqueous solutions of nitric acid at 25 °C was assessed in two independent ways. First, Raman experiments were carried out and interpreted in terms of free nitrate ions, ion pairs and neutral HNO(3) molecules. In parallel, a model was developed to account for the formation of these two kinds of pairs. It was based on an extension of the binding mean spherical approxi...

The Conversion Kinetics of Tincal to Boric Acid in Nitric Acid Solutions

Pure borax and various boron compounds are produced from the solutions in which tincal is dissolved with various reagents. Economically important boron compounds such as boric acid, borax, boric oxide, and refined hydrated sodium borates and perborates are produced from boron-containing ores. The production of boric acid by using nitric acid from tincal is more advantageous because it evalu...

Isoprenylation of Polyphenols in Aqueous Acid Solutions

Matract-Polyphenok condens with 2-methylbut-3cne-2-d or y,ydimethylallyl alcohol in 5% aqueous citric acid solution to yield phenolic 2Jdimethylchromans These facik condensation provide chemical support for the biogenetic theory of C-isopentenylation of phenols by 7,7dimcthylallyl pyrophosphate. Iso-psoralidin (20) has been synthesized from 7-hydroxy-2Jdimethylchroman (12) by a novel and conven...

Diffusion of levodopa in aqueous solutions of hydrochloric acid at 25 oC

Influence of aqueous diffusion layer on passive drug diffusion from aqueous cyclodextrin solutions through biological membranes.

Most drugs permeate biological membranes via passive diffusion and it is generally assumed that the main barrier is the lipophilic structure of the membrane. However, we have observed that the unstirred water layer adjacent to the membrane surface can in some cases be a barrier just as effective as the lipophilic membrane itself. Hydrophilic cyclodextrins can enhance drug delivery through biolo...