THERMODYNAMICS OF THE SYSTEMS HNO$sub 3$-H$sub 2$O-ETHERS

Technical Report · Wed Aug 01 00:00:00 EDT 1956

OSTI ID:4280488

Glueckauf, E; Davies, B

In the ternary system HNO/sub 3/-H/sub 2/O-Ether a great number of interactions between the components can be detected from an analysis of the activity and heat-ofmixing data. Solubility of H/sub 2/O in ethers alone at low concentrations of water is an endothermic process, but for ethers which can take up much water there is a cooperative effect between the dissolved water molecules, which renders the solution of water exothermic at higher water concentrations. Solution of HNO/sub 3/ in pure ether is strongly exothermic (~ 7.200 cal/mol) (apparently independently of the type of ether) and a 1 : 1 complex in formed by hydrogen bonding, which shows practically no dissociation except for ethers of high water solubility. The water uptake by water-free HNO/ sub 3/-ether mixtures is an exothermic process, the heat release varying greatly with the affinity of the ether for water, from a few hundred cal/mol H/sub 2/O for Bu/sub 2/O to 4,000 for dibutylcarbitol. In equilibrium with aqueous solutions of nitric acid, the HNO/sub 3/ uptake by the ether is at first proportional to the HHO/sub 3/ activity, and there is an additional water uptake by the ether, at first proportional to the HNO/sub 3/ uptake. This varies from 0.5 H/sub 2/O per HNO/sub 3/ for n-di-hexyl ether to 8 H/sub 2/O per HNO/sub 3/ for penta ether. The affinity of the ether for HNO/sub 3/ rises in the same order as the uptake of excess water, and the above-mentioned heat effects suggest that it is the tennary Ether-- HNO/sub 3/ H/sub 2/O interaction rather than the binary Ether-- HNO/sub 3/ interaction which determines the extraction affinity of the ether for HNO/sub 3/. All the ether solutions of nitric acid show, from their activity curves, that the dissolved nitric acid-ether complex in subject to a solute--solute attraction in the ether phase. In the case of poly-ethers, which contain more than 1 oxygen atom per molecule, when the molal ratio HNO/sub 3/: Ether = 1: 1 in approached, the other etber oxygens also take part in binding HNO/sub 3/, but with less heat release than the first oxygen atom. nitric acid per molecule of ether can be extracted into the ether, provided the ether is suffciently stable. In the case of Bu/sub 2/O the partial molar heat content of this excess HNO/sub 3/ is --3,450 cal/mol HNO/sub 3/ as compared with --7,500 for the first HNO/sub 3/ molecule. Detailed data are given for di-n-butyl ether and for di-butyl-carbitol. representing a mono- and a polyether, respectively. (auth)

• Research Organization: United Kingdom Atomic Energy Authority. Research Group. Atomic Energy Research Establishment, Harwell, Berks, England
• NSA Number: NSA-13-010832
• OSTI ID: 4280488
• Report Number(s): AERE-C/R-2029
• Country of Publication: United Kingdom
• Language: English

Related Subjects

ACTIVATION ENERGY
AFFINITY
ALKYL RADICALS
BINDING ENERGY
BUTYL RADICALS
CHEMICAL REACTIONS
CHEMISTRY
COMPLEXES
CONCENTRATION
DECOMPOSITION
DIAGRAMS
ENTHALPY
ETHERS
EXCITATION
HEATING
HYDROGEN
MIXING
MIXING HEAT
MOLECULES
NITRIC ACID
POLYMERS
QUANTITY RATIO
REACTION KINETICS
SOLUBILITY
SOLUTIONS
STABILITY
THERMODYNAMICS
WATER