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Title: Reactions of halogen-pyridine systems

Abstract

The combination of halogens (acceptors) with pyridine derivatives (donors) produces, initially, charge transfer complexes with conductivities useful as depolarizers in lithium-halogen power cell cathodes. The complex most often employed in pacemaker batteries is I/sub 2//P2VP. Pyridines and halogens undergo additional reactions of consequence to cell performance. Such side reactions include: Alkyl group substitution, ring coupling, polymer molecular weight degradation, olefin addition and ring substitution. Instrumental analysis of model systems and the commercial iodine/poly-2-vinylpyridine (I/sub 2//P2VP) system provided evidence for alkyl group substitution, coupling and molecular weight degradation. The addition reaction was inferred from the presence of the needed reactants and their facile reactivity. Halogenation of the pyridine ring was not found. Side reactions cause reduced cathode capacity. Hydrogen halides generated by such side reactions may cause corrosion, but may enhance conductivity properties. Deleterious pressure buidup or dimensional changes may result from side reactions occurring within sealed battery cans. 7 refs.

Authors:
;
Publication Date:
Research Org.:
Medtronic Inc, Minneapolis, Minn, USA
OSTI Identifier:
5423314
Resource Type:
Journal Article
Resource Relation:
Journal Name: Proc. - Electrochem. Soc.; (United States); Journal Volume: 80-4
Country of Publication:
United States
Language:
English
Subject:
25 ENERGY STORAGE; 62 RADIOLOGY AND NUCLEAR MEDICINE; CARDIAC PACEMAKERS; PRIMARY BATTERIES; CHEMICAL REACTIONS; HALOGENS; IONIC CONDUCTIVITY; LITHIUM; PYRIDINES; ALKALI METALS; AZINES; ELECTRIC CONDUCTIVITY; ELECTRICAL PROPERTIES; ELEMENTS; HETEROCYCLIC COMPOUNDS; METALS; NONMETALS; ORGANIC COMPOUNDS; ORGANIC NITROGEN COMPOUNDS; PHYSICAL PROPERTIES 250904* -- Energy Storage-- Batteries-- Other Applications; 550600 -- Medicine

Citation Formats

Coury, A.J., and Cahalan, P.T.. Reactions of halogen-pyridine systems. United States: N. p., 1980. Web.
Coury, A.J., & Cahalan, P.T.. Reactions of halogen-pyridine systems. United States.
Coury, A.J., and Cahalan, P.T.. 1980. "Reactions of halogen-pyridine systems". United States. doi:.
@article{osti_5423314,
title = {Reactions of halogen-pyridine systems},
author = {Coury, A.J. and Cahalan, P.T.},
abstractNote = {The combination of halogens (acceptors) with pyridine derivatives (donors) produces, initially, charge transfer complexes with conductivities useful as depolarizers in lithium-halogen power cell cathodes. The complex most often employed in pacemaker batteries is I/sub 2//P2VP. Pyridines and halogens undergo additional reactions of consequence to cell performance. Such side reactions include: Alkyl group substitution, ring coupling, polymer molecular weight degradation, olefin addition and ring substitution. Instrumental analysis of model systems and the commercial iodine/poly-2-vinylpyridine (I/sub 2//P2VP) system provided evidence for alkyl group substitution, coupling and molecular weight degradation. The addition reaction was inferred from the presence of the needed reactants and their facile reactivity. Halogenation of the pyridine ring was not found. Side reactions cause reduced cathode capacity. Hydrogen halides generated by such side reactions may cause corrosion, but may enhance conductivity properties. Deleterious pressure buidup or dimensional changes may result from side reactions occurring within sealed battery cans. 7 refs.},
doi = {},
journal = {Proc. - Electrochem. Soc.; (United States)},
number = ,
volume = 80-4,
place = {United States},
year = 1980,
month = 1
}
  • The gas to condensed phase transition technique has been used to study the iodine-128--ethane system. Total organic product yields were found to range from 1.1 (1 atm gas) to 61.2 percent (-23/sup 0/C liquid). Various molecular and enhancement reactions are evaluated using available data and a comparison is made among ethane and other two carbon hydrocarbons.
  • Potentiometric titrations of aquotitanium(III) with ferric ions have been performed in hydrochloric acid solution. The potentiometric data are described by E (V vs. NHE) = 0.03 - 0.059 log ((Ti(III))/(Ti(IV))(H/sup +/)/sup 2/) at 25/sup 0/C and 3.0 M ionic strength and are consistent with the interpretation that Ti/sup 3 +/(aq) and TiO/sup 2 +/ are the principal titanium(III) and titanium(IV) species, respectively, present at acid concentrations of 0.1 - 3.0 M. Rate constants for the oxidation of titanium(III) by a series of osmium(III) complexes, OsL/sub 3//sup 3 +/, where L is a bipyridine or phenanthroline derivative, have been determined atmore » 25/sup 0/C and 3.0 M ionic strength. The rates are interpreted in terms of the reactions of Ti/sup 3 +/(aq) and TiOH/sup 2 +/. The rate constants are correlated with the Marcus theory, and the exchange rate constants for the Ti/sup 4 +/ /sup 3 +/(aq) and TiOH/sup 3 +/ /sup 2 +/ couples are estimated. The rate constants for the reaction of titanium(III) with the excited states of the ruthenium(II) complexes RuL/sub 3//sup 2 +/ are insensitive to the reduction potentials of the ruthenium(II) complexes. Arguments are presented to show that the quenching reactions proceed predominatly by energy-transfer mechanisms. The implications of these results for the production of Ti/sup 2 +/(aq) in quenching reactions are discussed. 6 figures, 5 tables.« less
  • The irradiation of Ru(bpy)/sub 3//sup 2 +/, and triethanolamine (TEOA) solutions 10/sup 9/ 8, 25/sup 0/C) with 450 +- 20-nm light yields rhodium(I) phi = 0.13 +- 0.02) ( units for phi in mol einstein/sup -1/ throughout the paper) and dihydrogen (phi = 0.11 +- 0.02) in the absence and presence of platinum, respectively. A detailed mechanistic scheme has been deduced from the results of continuous- and flash-photolysis experiments: light absorption by Ru(bby)/sub 3//sup 2 +/ gives the excited state *Ru(bpy)/sub 3//sup 2 +/ which is oxidized by Rh(bpy)/sub 3//sup 3 +/ (k = 3.9 x 10/sup 8/M/sup -1/s/sup -1/)more » yielding Ru(bpy)/sub 3//sup 3 +/ and Rh(bpy)/sub 3//sup 2 +/ with a cage escape yield of 0.15 +- 0.03. Back-reaction of Ru(bpy)/sub 3//sup 3 +/ with Rh(bpy)/sub 3//sup 2 +/ (k = 3 x 10/sup 9/M/sup -1/s/sup -1/) is prevented by reduction of Ru(bpy)/sub 3//sup 3 +/ by TEOA (k = 0.2 x 10/sup 8/M/sup -1/s/sup -1/). The oxidized TEOA radical so generated undergoes a TEOA-promoted rearrangement (k = 0.3 x 10/sup 7/M/sup -1/s/sup -1/) to a reducing radical. The latter reduces Rh(bpy)/sub 3//sup 2 +/ so that the net yield for Rh(bpy)/sub 3//sup 2 +/ formation is 0.3 +- 0.1. Rate-determining loss of bpy from Rh(bpy)/sub 3//sup 2 +/ (k = 1.0 +- 0.5 s/sup -1/) is followed by rapid reduction of Rh(bpy)/sub 2//sup 2 +/ by Rh(bpy)/sub 3//sup 2 +/ (k = 0.3 x 10/sup 9/M/sup -1/s/sup -1/) giving Rh(bpy)/sub 3//sup 3 +/ and Rh(I). In the presence of platinum, H/sub 2/ is formed at the expense of Rh(I); catalyzed reaction of Rh(II) with water occurs before disproportionation to Rh(I) can take place. The H/sub 2/ quantum yield in this system is limited only by the cage escape of the primary products, the homogeneous and heterogeneous dark reactions being very efficient. In the course of this study the electrochemistry of Rh(bpy)/sub 3//sup 3 +/, Rh(phen)/sub 3//sup 3 +/, and Rh(bpy)/sub 2/(OH)/sub 2//sup +/ in aqueous solution was investigated, and the quenching of Ru(bpy)/sub 3//sup 2 +/ emission by these Rh(III) complexes was characterized.« less
  • The quenching of *RuL/sub 3//sup 2 +/ (L is a 2,2'-bipyridine or 1,10-phenanthroline derivative) emissions by three classes of oxidants Q has been examined. The results are discussed in terms of the Marcus electron-transfer model recast in a preequilibrium formalism. Substituted bipyridinium cations (methyl viologen and related compounds) undergo thermodynamically favorable reduction with a driving force ranging from 0.1 to 0.7 eV and rate constants in the range (0.4-2.0) x 10/sup 9/ M/sup -1/s/sup -1/, consistent with a diffusion rate constant of 2.0 x 10/sup 9/ M/sup -1/s/sup -1/ and an exchange rate constant of approx.10/sup 6/ M/sup -1/s/sup -1/more » for the Q-Q couples. The yields of the separated redox products RuL/sub 3//sup 3 +/ and Q/sup -/ (typically 0.1 mol einstein/sup -1/ per quenching act) require K/sub 30/, the ''intramolecular'' back-reaction rate constant (to re-form ground-state RuL/sub 3//sup 2 +/ and Q), to be (2-4) x 10/sup 10/ s/sup -1/. Since K/sub 30/ increases weakly with driving force in this series, there is no evidence for inverted behavior despite the fact the ..delta..G/sup 0//sub 30/ is approx.-2 eV. With Q = Rh(4,4'-(CH/sub 3/)/sub 2/bpy)/sub 3//sup 3 +/, the quenching rate constants, k/sub q/ = (0.001-1.0) x 10/sup 9/ M/sup -1/s/sup -1/, exhibit a great sensitivity to the reducing power of *RuL/sub 3//sup 2 +/ and have been fitted to k/sub 11/ approx. = 2 x 10/sup 9/ M/sup -1/s/sup -1/ and E/sup 0//sub Q,Q/sup -// = -0.97 V for the RhL/sub 3//sup 3 +/-RhL/sub 3//sup 2 +/ couple. This E/sup 0/ value is strikingly similar to that (-0.9 V vs. aqueous SCE) obtained via cyclic voltammetry in acetonitrile. The cyclic voltammetry of the RhL/sub 3//sup 3 +/ complexes in water has been reexamined, and it is concluded that the irreversibility observed is due to ligand loss from rhodium(I).« less