bluuebunny/crossref_metadata_2025 huggingface dataset:
Studies of Australian soft corals. IX. A novel nor-diterpene from the soft coral Sinularia leptoclados
Authors: Bowden BF , Coll JC , Mitchell SJ , Mulder J , Stokie GJ
Published: September 2010

The structure of a novel
nor-cembranoid diterpene of formula C19H24O6
(1) is reported. The compound was extracted from the soft coral Sinularia
leptoclados, and spectroscopic data were collected on the parent compound (1)
and a series of derivatives. It was not possible to assign an unambiguous structure
on purely spectroscopic grounds, and so single-crystal X-ray analysis was used
to prove the structure (1): (4R*,8S*,11R*,13S*,14R*)-14-hydroxy-4-isopropenyl-11-methyl-6,9-dioxo-8,11-epoxycyclotetradec-1-ene-1,13-carbolactone.
Open-circuit space-charge distribution in an insulator whose trap density varies exponentially with distance
Authors: Bonham JS
Published: September 2010

Analytic expressions are
derived for the equilibrium injected charge distribution in an insulator with hole-injecting
contacts. The trap density is assumed to vary exponentially in both space and
energy, and the formulation encompasses the special cases of uniform spatial
and shallow energetic trap distribution.
Effects of some orthophosphates on the hydration of calcium sulfate hemihydrate
Authors: King GA , Ridge MJ
Published: September 2010

The effects of some
orthophosphates on the rate of hydration of calcium sulfate hemihydrate have
been determined in terms of two basic parameters, viz. α0,
which is a measure of seeding in the system, and k, which is a measure of the
rate of transfer of calcium sulfate from the lattice of the hemihydrate to that
of the dihydrate. Measurements were made of pH and the activities of calcium
ions. ��� The only dispersed, undissolved phosphate
to affect the reaction was secondary calcium phosphate dihydrate (CaHPO4,2H2O)
which is structurally similar to gypsum and appeared to increase nucleation. ��� The actions of the soluble orthophosphates,
primary calcium phosphate Ca(H2PO4)2,H2O
and the secondary sodium phosphate Na2HPO4, were studied
in detail. The effects were various and depended upon the amount added, the pH
and residues from incongruent dissolution. Attempts to explain inhibitions in
terms of concentrations of the species, H2PO4-,
HPO42-, CaH2PO4+ and
CaHPO4O were unsuccessful.
Nitrones and oxaziridines. XXII. Preparation and cyclization of some δ,ε-unsaturated hydroxylamines
Authors: Black DSC , Doyle JE
Published: September 2010

Four δ,ε-unsaturated
hydroxylamines have been prepared by reduction of the related oximes by sodium
cyanoborohydride. Only two of these-those containing terminal olefinic
groups-undergo spontaneous cyclization to N-hydroxypyrrolidines, which can be
oxidized easily to 1-pyrroline 1-oxides. The acyclic and cyclic hydroxylamines
have been characterized by their products of reaction with phenyl isocyanate.
Decyanation of 9-Allylfluorene-9-carbonitrile and 2,2-Diphenylpent-4-enenitrile with lithium aluminium hydride
Authors: Black DSC , Doyle JE
Published: September 2010

Decyanation of
9-allylfluorene-9-carbonitrile and 2,2-diphenylpent-4-enenitrile is effected
with lithium aluminium hydride to a greater extent than reduction to the
corresponding amines. Related diphenylacetonitriles undergo reduction only.
N.M.R. studies on myelin basic protein. II. 1H N.M.R. studies of the protein and constituent peptides in aqueous solutions
Authors: Littlemore LAT
Published: September 2010

1H N.M.R. spectra (270 MHz) of myelin basic protein
(MBP) at pD 3.7 in D2O were obtained as a
function of concentration and compared with computed spectra. Reduced line
widths obtained for 0.5-mM samples and use of the convolution difference
technique enabled detection of chemical shift heterogeneities for histidine,
tyrosine, methionine, threonine, and isoleucine residues in the protein; this
is indicative of secondary/tertiary structure. Chemical shift assignments were
confirmed by the use of the Carr-Purcell A pulse sequence and selective
decoupling as well as by correlation of the MBP spectrum with that of its
constituent cathepsin D digest peptides. The methyl resonance from the unique
methylated arginine-107 was found, and its chemical shift compared to that of NG-monomethyl-L-arginine and the methylated arginine peak in
the peptide fragment, residues 90-170. The absence of ring- current effects on
the methyl chemical shift precludes conformations of MBP in which the
methylarginine interacts with the phenylalanine pair at residues 89 and 90.
The crystal and molecular structure of tetraphenylarsonium Tetrakis(benzenethiolato)oxomolybdate(V)
Authors: Bradbury JR , Mackay MF , Wedd AG
Published: September 2010

Crystals of the title
compound, Ph4As+ [MoO(SPh)4]-, belong to the triclinic
space group Pī with cell dimensions a 12.623(8),
b 14.295(7), c 14.301(9) Ǻ, α 94.43(4), β 111.43(5), γ
65.70(4)° and Z2. The structure has been refined with diffractometer data measured
with Mo Kα radiation to give a conventional R
factor of 0.056 for 3215 unique terms. The Mo, As, S and O atoms were refined
with anisotropic temperature factors and the C atoms with isotropic factors. The
square- pyrimidal [MoO(SPh)4]-
anion has the Mo atom lying 0.82 Ǻ from the basal plane of the four S
atoms with Mo-O 1.699(9) Ǻ, the mean Mo-S bond lengths 2.403(5) Ǻ and
the mean S...S distance 3.20(3) Ǻ. The geometry about the As atom in the
Ph4As+ cation is regular tetrahedral, the mean As-C bond
length being 1.91(1) Ǻ.
Crystal structure of Tris(pyridine-2-carboxylato)manganese(III) monohydrate
Authors: Figgis BN , Raston CL , Sharma RP , White AH
Published: September 2010

The crystal structure of
the title compound, [Mn(C5H4NCO2)3],H2O,
has been determined by single-crystal X-ray diffraction at 295 K and refined by
least squares to a residual of 0.053 for 2234 'observed' reflections. Crystals
are monoclinic, C2/c, a 30.50(2), b 8.387(8), c 13.903(7) Ǻ, β
94.15(3)°, Z 8. The geometry of the manganese environment displays a
pseudo-tetragonal distortion, the axial atoms being nitrogen (Mn-N 2.254(6), 2.217(6) Ǻ). The equatorial atoms are
at distances Mn-N 2.059(5) Ǻ, Mn-O 1.891(5), 1.908(5), 1.942(5) Ǻ, the latter being
trans to the nitrogen. The occupancy of the water molecule site is 0.54(1).
Nitration of 2-phenylcyclohexanone
Authors: Bell KH
Published: September 2010

Nitration of
2-phenylcyclohexanone (1a) with mixed acid results in oxidative cleavage to a
mixture of nitrobenzoic acids but use of copper(II) nitrate in acetic anhydride
yields 2-(4'-nitrophenyl)cyclo-hexanone (1b) and
smaller amounts of 6-(4'-nitrophenyl)-6-oxohexanoic acid (2).
Carbon-13 N.M.R. chemical shifts and rotational barriers of para-substituted N,N-dimethylbenzamides
Authors: Fong CW , Lincoln SF , Williams EH
Published: September 2010

The carbon-13 N.M.R.
chemical shifts for a series of para-substituted N,N-dimethylbenzamides have
been measured. The substituent induced 13C shifts have been examined
by a dual substituent parameter (DSP) method using Hammett-type constants. The
barriers to rotation have also been correlated with Hammett-type constants by
the DSP method and related to 13C substituent induced shifts.
Substituent effects of the bromomethyl, dibromomethyl and tribromomethyl groups
have been examined by using the chemical shift and rotational barrier probes.
Some sulfonyl derivatives of phenoxyacetamide
Authors: Cremlyn RJ , Pannell RW
Published: September 2010

Phenoxyacetamide (2) by
treatment with chlorosulfonic acid gave the 4- sulfonyl chloride (3); this was
characterized by preparation of the sulfonamide (4) and the sulfonohydrazide
(5). The latter compound has been converted into five hydrazones (6) by condensation
with the appropriate carbonyl compounds; with acetylacetone cyclization
occurred to form the 3,5-dimethylpyrazole (7). 2,4-Dichloro- and 4-chloro-2- methyl-phenoxyacetamides were chlorosulfonated to the
corresponding 6- sulfonyl chlorides (8) and (10), and these were characterized
as the sulfonohydrazides (9) and (11). In contrast, attempts to chlorosulfonate
2,4-dichloro- and 4-chloro-2-methyl-phenoxyacetic acids were unsuccessful, and
the reasons for this failure are briefly discussed.
Photochemistry of heterocyclics. II. Photolysis of benzimidazole and its 2-alkyl derivatives
Authors: Cole ER , Crank G , Lye E
Published: September 2010

Photolysis of benzimidazole
in various solvents with free access to air gives the unsymmetrical dehydro
dimers, 2,4'- and 2,5'-bibenzimidazole. By contrast, 2-alkylbenzimidazoles do
not give dimers but produce a mixture of acyl derivatives with improved yields
in acidic solvent, e.g. 2-methylbenz-imidazole gives a mixture of 1-acetyl-,
4-acetyl- and 5-acetyl-2-methylbenzimidazole. A mechanism is suggested wherein
a common path is followed in the initial stages. A photoexcited species first
abstracts a hydrogen atom and then reacts with a ground-state substrate
molecule to give a 2,3-benzimidazoline dimer. Subsequent reactions depend on
the nature of the group at the 2-position of the benzimidazole-if hydrogen
oxidation to dehydro dimer occurs but with an alkyl group a mixture of acylated
benzene ring and o-phenylenediamine derivatives is produced by hydrolytic
fission. Quantum yields of 1.52- 1.90 provide support for this scheme.
Studies of Australian soft corals. X. The isolation of epoxyisoneocembrene-A from Sinularia grayi and isoneocembrene-A from Sarcophyton ehrenbergi
Authors: Bowden BF , Coll JC , Hicks W , Kazlauskas R , Mitchell SJ
Published: September 2010

The isolation of an epoxyisoneocembrene-A [(E,E,E)-11,12-epoxy-1- isopropyl-4,8,12-trimethylcyclotetradeca-1,3,7-triene]
(1), from the soft coral Sinularia grayi, is reported
and its structure demonstrated by chemical and spectroscopic means. The
isolation of an isomer of the reported cembrene sarcophytoxide (2) and of
isoneocembrene-A (3), an isomer of the termite trail pheromone neocembrene-A, from the soft coral Sarcophyton
ehrenbergi is also reported. Chemical transformations
enabled (1) to be converted into (3).
A Model Theoretical Study for Alkylation in Benzimidazoles: ab initio Electrostatic Potentials
Authors: Hinde AL , Radom L , Rasmussen M
Published: September 2010

Ab initio molecular
orbital theory is used to study the protonation of benzimidazole anions. Both
kinetically and thermodynamically controlled processes are considered for the
unsubstituted and for NH2, NO2 and CN substituted
systems. Extensive use is made of molecular electrostatic potential (m.e.p.)
maps to predict kinetically preferred sites of protonation. Predictions made on
this basis are consistent with experimental data on alkylation of these and
closely related systems. In contrast, other approaches based on theoretical
charges or frontier orbital coefficients do not correlate well with the
experimental results.
Synthetic Applications of Intramolecular Insertion in Arylcarbenes. I. o-Alkylphenylcarbenes and 1-(o-Alkylphenyl)ethylidenes
Authors: Crow WD , McNab H
Published: September 2010

A series of phenylcarbenes
and 1-phenylethylidenes, substituted in the ortho-position
by alkyl chains of 1-4 carbon atoms, has been generated in the gas phase and
pyrolysed at 250-750°/0.05-0.10 mm. Apart from o-tolylcarbene, the phenylcarbenes show efficient insertion to form
five- and six-membered rings, the former predominating. In the
phenylethylidenes, Bamford-Stevens insertion into the adjacent methyl group
competes with cyclization to an extent which decreases with chain length. At
the same time, five-membered ring formation is greatly increased over
six-membered ring formation, due to facilitation of out-of-plane twisting of
the carbene atom. The mechanistic implications of the results are discussed in
terms of an angular approach of the carbene p-orbital to the hydrogen atom
under attack.
Synthetic Applications of Intramolecular Insertion in Arylcarbenes. IV. o-Alkoxy-, Dialkylamino- and Alkylthio-1-phenylethylidenes
Authors: Crow WD , McNab H
Published: September 2010

A series of 1-phenylethylidenes,
substituted in the ortho-position by
alkoxy, dialkylamino and alkylthio side chains containing up to three carbon
atoms, has been generated in the gas phase and pyrolysed at 250-750�/0.05-0.30
mm. Carbene insertion to form five-membered heterocyclic rings predominates,
with up to 20% Bamford-Stevens insertion, to give the styrenes;
little or no formation of six-membered rings is observed. In cases where
stereoselective insertion is possible, the trans-disubstituted heterocycle is
formed preferentially, the selectivity being greatest in the case of
dialkylamino substitution. The mechanisms involved are discussed in terms of
transition state geometry.
19-Nor and Aromatic Steroids. III. The Conversion of 3β-Acetoxy-5α-lanost-8-en-7-one into Steroids with A and B Rings Aromatic
Authors: Cooper PS , Culshaw CM , Gall RE , Nemorin JE
Published: September 2010

Benzylic oxidation of 3,β,7-diacetoxy-19-norlanosta-5(10),6,8-trine
(6b) resulted in a mixture of the 11-one (7) and the 1,11-dione (8a) whilst
similar oxidation of 3β-acetoxy-7-methoxy-19-norlanosta-5(10),6,8-triene
(6c) gave a mixture of the 1-one (9) and the 1,11-dione (8b). The 3β-acetoxy
1-ones (8a), (8b) and (9) readily eliminated acetic acid to give the
2-en-1-ones (11a), (11b) and (10) respectively. Attempts to aromatize the A
ring in the three ketones (11a), (11b)
and (10) with loss of one of the methyl groups at C4, failed since zinc in
either acetic acid or aqueous dimethylformamide gave
the reduced ketones (13a), (13c) and (13b). Under acidic conditions the same
ketones (11a), (11b) and
(10) underwent the dienone-phenol rearrangement to give the 1-acetates (17a),
(17c) and (17b). The 2-en-1-one (10) when reduced with lithium aluminium
hydride gave the 1-ols (15) and 3,4,14α-
trimethyl-19-norcholesta-1,3,5(10),6,8-pentaene (16), probably arising by
dehydration of the dienols (14). Reduction of 4,4-dimethylnaphthalen-1(4H)-one (23) with zinc in acetic acid
gave 4,4,dimethyl-3,4-dihydronaphthalen-1(2H)-one
(21) and 1,2-dimethylnaphthalene (25) and none of the phenol (26).
Long-chain and other substituted 2-Nitrophenyl active ester derivatives of some amino acids
Authors: Stewart FHC
Published: September 2010

Various
4-carboxamido-substituted 2-nitrophenols have been obtained by reaction of
active polyester intermediates with aliphatic amines including long-chain, chiral, and diamine representatives. Someof the compounds were used
as precursors of long-chain and other active ester derivatives of L-alanine and L-proline.
Organophosphorus Compounds. II. Ethyl Phenylphosphinate
Authors: Hewitt DG
Published: September 2010

Ethyl phenylphosphinate,
PhPH(=O)OEt, is
conveniently prepared in one step by the reaction of phosphinic
acid with ethyl chloroformate in the presence of
pyridine.
Photoelectron Spectroscopic Studies of Piperidine and its N-Halo Derivatives
Authors: Gan T , Peel JB
Published: September 2010

The HeI
photoelectron spectra of N-chloropiperidine and N-bromopiperidine have been measured and compared with that
of piperidine. The ionization energies associated
with the nitrogen lone- pair and halogen non-bonding electrons indicate that
there is considerably less nN-nx
resonance interaction than in the smaller halo amines. HeII studies
show that the halogen character is localized in both the N-halopiperidines with most ionization
energies showing simple inductive shifts resulting from halogenation.
The Effects of Isotopic Dilution on the Infrared Spectrum of Solid Sodium Formate
Authors: Spinner E , Rowe JE
Published: September 2010

Infrared spectra (4000-200 cm-1; KBr discs) have been obtained for ten isotopic species of solid
sodium formate in bulk (isotopic purities ranging from 80% to 99%) and after isotopic dilution.
In probably the most systematic and comprehensive study of its kind to date on a polyatomic solid,
a large number of solid solutions, such as H12C16O2Na in D13C18O2Na and vice versa, D12C16O2Na
in D13C18O2Na and vice versa, etc., have been examined (solute concentration usually in the range
from 15% to 1 %). The CH and CD out-of-plane and in-plane bending frequencies are raised
somewhat on isotopic dilution, the CH and CD stretching, OCO scissoring and lower CO stretching
frequencies are lowered a little. For the latter two vibrations the frequency of the solid solute is
affected by that of the solid solvent only very slightly (by 0.5 cm-1 to 1.0 cm-1), but in a very
regular and systematic manner. For the higher carboxylate stretching frequency, by contrast, the
effect of isotopic dilution is much more varied. The solute frequency is raised (e.g. by 3.5 cm-1
for H12C16O2Na in D13C18O2Na), or lowered (e.g. by 6.5 cm-1 for D13C18O2Na in H12C16O2Na,
18 cm-1 for H13C16O2Na in H12C16O2Na, 22 cm-1 for H13C16O2Na in D13C18O2Na), depending
on whether the intrinsic solute frequency is higher or lower than that of the solvent, and by an
amount determined by the separation between the two. Thus, for this vibration strong coupling
between solute anion and solvent anions is still conspicuous after isotopic dilution, and the 'solute'
spectra observed are those of a cluster of solute anion surrounded by solvent anions; they do not
usually approximate to the spectra of individual isolated solute ions. Some combination frequencies
show much lower anharmonicity corrections after isotopic dilution than in bulk. With isotopically
mixed crystals transfer of absorption intensity is observed, to the bands at lower frequencies for
CH and CD in- and out-of-plane bending, and to those at higher frequencies for OCO scissoring
and both CO stretching vibrations. For larger crystals and solid films, an instance was found of a
large intensity transfer to higher frequencies, additional to the (small) one seen with KBr discs.
A satisfactory explanation in terms of the crystal structure is at present available only for the out-
of-plane bending results.
Coordination of 2,2'-Biimidazole with Iron, Cobalt, Nickel and Copper
Authors: Abushamleh AS , Goodwin HA
Published: September 2010

Complexes of
2,2'-biimidazole with bivalent iron, cobalt, nickel and copper, and trivalent
iron are described. The ligand produces a relatively weak field and all
complexes are high-spin and markedly less stable than corresponding complexes
of 2,2'-bipyridine or 2-(2-pyridyl)imidazole. Inner complexes, M(L-H)2,
derived from the monoanion of biimidazole are also described. The complexes are
characterized by magnetic and spectral data.
The Synthesis of (25R)-22αN-[15ξ,17α-2H2]-Spirosol-5-en-3β-ol ([15ξ,17α-2H2] Solasodine) and Assignment of the 13C N.M.R. Spectra of Solasodine and its Derivatives
Authors: Bird GJ , Collins DJ , Eastwood FW , Exner RH , Romanelli ML , Small DD
Published: September 2010

(25R)-22αN-[15ζ,17α-2H2]Spirosol-5-en-3β-ol
([15ζ,17α-2H2]solasodine) has been synthesized
from solasodine and used to make unambiguous assignments of the resonance
signals for C13, C14, C15, C17 and C20 in the 13C N.M.R. spectrum of
solasodine. The complete assignments of the 13C N.M.R. spectra of
solasodine and some of its derivatives are based on this, on paramagnetic
broadening of signals due to C22, C23, C25 and C26, and on chemical shift
considerations.
The Structure and Function of Oestrogens. II. The Synthesis and Oestrogenic Activity of 4b-Methyl 4b,5,6,12-tetrahydrochrysene-2,8-diol and 4b-Methyl-cis-4b,5,6,10b,11,12-hexahydrochrysene-2,8-diol and Related Compounds
Authors: Collins DJ , Matthews WA , Stone GM
Published: September 2010

Hydroboration of an inseparable mixture of 2,8-dimethoxy-5,6-dihydrochrysene
(5a) and 2,8-dimethoxy-4b-methyl-4b,5,6,12-tetrahydrochrysene (6a) followed by
oxidation with alkaline hydrogen peroxide gave a mixture of (4bα,10bβ,11β)-2,8-dimethoxy-4b-methyl-4b,5,6,10a,11,12-hexahydrochrysen-11-ol
(10a) and its (4bβ,10bβ,11β) isomer(11a).
Reduction of the methanesulfonate ester of (10a) with
lithium aluminium hydride in ether gave 2,8-dimethoxy-4b-methyl-trans-4b,5,6,10b,11,12- hexahydrochrysene (2b), identical with material prepared by
another route. Reduction of the methanesulfonate of
(4bβ,10bβ,l1β)-2,8-dimethoxy-4b-methyl-4b,5,6,10a,11,12-hexahydrochrysen-
11-ol afforded 2,8-dimethoxy-4b-methyl-cis-4b,5,6,10b,11,12-hexahydrochrysene
(12), demethylation of which afforded 4b-methyl-cis-4b,5,6,10b,11,12-hexahydrochrysene-2,8-diol
(14b). Dehydration of the mixture of the 11-epimeric alcohols (10a) and (lla) with phosphorus oxytrichloride
in pyridine yielded pure 2,8-dimethoxy-4b-methyl-4b,5,6,12-tetrahydrochrysene
(6a) which was demethylated with methylmagnesium
iodide to give the corresponding dihydroxy compound
(9). Other compounds prepared in the course of examining possible routes to (9)
and (14b) include 13,13-dichloro-2,8-dimethoxy-4b,5,6,10b,11,12-hexahydro-4b,10b-methanoch
rysene (3a), 1-bromo-
2,8-dimethoxy-5,6-dihydrochrysene (5b), and
11-bromo-2,8-dimethoxy-4b-methy1-4b,5,6,12-tetra- hydrochrysene
(7). The oestrogenic activities of some of the new
angularly methylated hydrochrysenes
and of 9α- methyloestradiol (15) are reported.
The Crystal Structure of [2,6-Bis(1-methyl-4-methylthio-5-thia-2,3-diazahexa-1,3-dienyl)-pyridine]dithiocyanatonickel(II), a Complex of a Potentially Pentadentate N3S2 Ligand, and a Comparison with Complexes of an N3O2 Ligand
Authors: Choong W , Stephenson NC , Ali MA , Malik MA , Phillips DJ
Published: September 2010

The crystal structure of
Ni(dapsm)(NCS)2 [dapsm
is 2,6-bis(1-methyl-4-methylthio-5-thia-2,3-diazahexa-1,3-dienyl)pyridinel has been determined from three-dimensional
single-crystal diffractometer X-ray data. Structure refinement was carried out
by least-squares methods to a final R value of 0.059. The ligand dapsm is a potential N3S2
pentadentate, but it coordinates as a tetradentate,
giving a planar N3S donor grouping. Rotation occurs about an N-N
bond in dapsm, moving a potential donor sulfur atom
away from the nickel(II) ion. The pyridine ring of the ligand, and the N3S
donor grouping, are approximately coplanar. Two thiocyanate
groups are coordinated to the nickel, giving a distorted octahedral structure.
The structure and electronic spectrum of Ni(dapsm)-
(NCS)2 are compared with those for seven-coordinate complexes with
the related N3O2 ligand, 2,6-diacetylpyridine bissemicarbazone.
Carbon-13 N.M.R. Analysis of Tutin and Related Substances: Application to the Identification of Minor Components of Toxic Honey.
Authors: Blunt J , Munro MG , Swallow W
Published: September 2010

The application of
carbon-13 N.M.R. microsample probe techniques has
been employed to show the presence of dihydrotutin
and dihydrohyenanchin as trace components of a range
of toxic honeydew honeys. The 13C N.M.R. spectra of a series of
compounds related to tutin, hyenanchin
and picrotin have been assigned.
Carbon-13 N.M.R. Studies of Carbocations. III. An Investigation of the Variation of ipso-Substituent Chemical Shifts with Electron Demand in 1,4-Disubstituted Benzenes
Authors: Hugel HM , Kelly DP , Spear RJ , Bromilow J , Brownlee RTC , Craik DJ
Published: September 2010

13C n.m.r. spectra have been obtained of a large range of 1(X),4(Y)-disubstituted benzenes in which
X has been varied over a range of 25 substituents from NMe2 to +CHMe for each of the compounds
where Y = H, OMe, Me, F, Cl, Br and CF3. The ipso-substituent chemical shifts (ipso-SCS) for
each of the latter (that is, the change in chemical shift (Δδ) of C4 by replacement of H by Y) have
been shown to vary dramatically with the electron demand of the X substituent as measured by
δ(C4). When plotted against ?(C4), the ipso-SCS of F and OMe both decrease linearly with increasing
electron demand whilst those of Br and Cl show linear increases. Those of Me and CF3 show discontinuities which indicate changes in the mechanism of interaction of these groups with the attached
ipso-carbon. The variations in the ipso-SCS with electron demand of X are considered to be due to
Y-induced variations in the sensitivity of the ipso-carbon to the effect of the para (X) substituent
and not to through-conjugation effects. The results clearly show the fallacy of assuming that 13C
substituent effects are constant.
Covalent Additions of Glutathione, Cysteine, Homocysteine, Cysteamine and Thioglycolic Acid to Quinazoline Cation
Authors: Pitman IH , Morris IJ
Published: September 2010

A linear relationship with
a gradient of 0�38 was found to exist between the γ values of thiols and the pKa values of their mercapto groups. The γ value of a nucleophilic reagent
is a relative measure of the extent to which it will covalently add across >C=N-,>C=O
and >C=C< groups, γ values
for the thiols were calculated from the equilibrium constants for their
covalent addition to quinazoline cation at 25�, l 0.1 M. The results indicate that substituents in a thiol
influence both the pKa
value of the mercapto group and the γ
value in a similar manner but they have a significantly greater effect on the
pKa value.
The Absolute Configuration of a Sesquiterpene Enone From Stevia purpurea and a Phenol From Lasianthaea podocephala
Authors: Ghisalberti L , Jefferies P , Stuart A
Published: September 2010

(6S,1'R)-6-(1',5'-Dimethylhex-4'-enyl)-3-methylcyclohex-2-enone (1a) has been prepared and found
to be the enantiomer of an enone obtained from Stevia purpurea. Oxidation of enone (1a) gives
(R)-2-(1',5'-dimethylhex-4'-enyl)-5-methylphenol, identical with a natural product from Lasianthaea
podocephala.
Amino Acids of the Tropolone Series: The Synthesis of DL-α-Amino-β-(2-hydroxy-5-methyl-3-oxocyclo-hepta-1,4,6-trienyl)propanoic Acid
Authors: Teitei T
Published: September 2010

The synthesis of DL-α-amino-β-(2-hydroxy-5-methyl-3-oxocyclohepta-1,4,6-trienyl)propanoic
acid(4b) by conventional procedures from 4-methyltropolone
(2-hydroxy-4-methylcyclohepta-2,4,6-trien-1-one) is described.
Substituent Effects on the Micelle-Catalysed and Uncatalysed Basic Hydrolysis of a Series of Substituted N-Methyl-p-toluanilides
Authors: Broxton TJ , Duddy NW
Published: September 2010

The rate of hydrolysis of a
series of substituted N-methyl-p-toluanilides has been measured in
water and in the presence of cationic micelles [cetyltrimethylammonium bromide
(ctab)]. A Hammett correlation of the rates of hydrolysis gave a curved Hammett
plot for the reaction in water (k2,W) but a linear plot for the rate
of reaction at optimal concentrations of ctab (k2,max) and for
derived rate constants within the micelle (k2,m) These results are
discussed in terms of the mechanism of reaction, and for two compounds a
micelle-induced change of mechanism is indicated.
Quinazolines. XXIV. The Synthesis of 2,4-Diazatetra-cyclo[7,3,1,17,11,01,6]tetradecanes(Adamantano [1,2-d]pyrimidines)
Authors: Armarego WLF , Tucker PG
Published: September 2010

The syntheses of
6-hydroxy-2,4-Diazatetracyclo[7,3,1,17,11,01,6]tetradecan-3-iminium
(4) picrate and related compounds starting from 2-oxoadamantane-1-carbonyl
chloride (5) are described. In preliminary biological evaluation it was found
that the most toxic (M.L.D. values for mice) adamantane derivative, 3,5
diazatetracyclo[7,3,1,17,11,01,6]tetradecane-2,4-dione
(76 mg kg-1), was much less toxic than tetrodotoxin (0.013 mg kg-1).
A Proton Magnetic Resonance Study of Ligand Exchange on Tetrakis(tetramethylthiourea)zinc(II) Ion
Authors: Tkaczuk MN , Lincoln SF
Published: September 2010

The rate of ligand exchange
on the tetrakis(tetramethylthiourea) zinc(II) ion, determined by 1H
N.M.R. methods, in CD2Cl2 solution is found to be
independent of free-tetramethylthiourea concentration. This is consistent with
a dissociative ligand-exchange mechanism being operative. Typically for a
solution in which [Zn{S=C(NMe2)2}42+]
and [S=C(NMe2)2] were 0�00101 and 0�00376 respectively, kex(200
K) = 16�0�0.6 s-1, ΔH‡ = 64�9�O.8 kJ mol-1 and ΔS‡
= 106�4 J K-1 mol-1 where the observed ligand-exchange
rate is given by rate = 4kex[Zn {S=C(NMe2)2}42+]
The preparations of [Zn(O=CHNMe2)6](ClO4)2,
[Zn{O=CMe(NMe2)}6](Cl04)2, and
[Zn{O=C- (NMe2)2}4](ClO4)2
are also reported. The rate of ligand exchange upon these three species in CD2Cl2
solution was found to be in the fast-exchange limit of the N.M.R. time scale.
Photochemistry of Azole N-Oxides. II. Photoisomerization of Tetraaryl-1H-imidazole 3-Oxides
Authors: Woolhouse AD
Published: September 2010

Tetraaryl-lH-imidazole 3-oxides (1) can be
photochemically isomerized to unsymmetrical (Z,Z)-benzil diimine derivatives
(5), in yields which are of preparative value. Evidence which, for the first
time, suggests that fused oxaziridines (2) are likely intermediates in the
photochemistry of this class of aromatic azole N-oxides is also presented.
The Kinetics and Mechanism of Substitution of Square-Planar Complexes of Nickel(II), Palladium(II) and Platinum(II) Containing Sulfur Ligands
Authors: Fayyaz MU , Grant MW
Published: September 2010

The kinetics of
substitution of nickel(II) ethylxanthate, dialkyldithiophosphate,
diphenyldithiocarbamate and monothioacetylacetonate complexes, and palladium
and platinum(II) ethylxanthate and dithiophosphate complexes by dithiocarbamate
ion have been studied in acetone. In general, second order kinetics were
observed; in some systems the mixed-ligand complex was observed as an intermediate
while in others no intermediates were detected. An intermediate observed in the
platinum ethylxanthate and diethyldithiocarbamate reaction is square-planar
with two monodentate dithiolate ligands. Rates of substitution of the
dithiophosphates for nickel, palladium and platinum are in the ratio 9 × 105
: 1900 : 1 and the sequence is shown to be an effect of increasing activation
enthalpy. Contrary to earlier reports, variations of rates of substitution of
nickel(II) complexes do not reflect in any simple way the ability of the nickel
atom to expand its coordination shell, nor the thermodynamic stability of the
complexes, and it is proposed that there is a significant contribution from
bond-breaking in these reactions.
Constituents of Eupomatia Species. V. The Isolation of Eupomatenoid-13 (a New Neolignan), (±)-trans-Dehydrodiisoeugenol, and Other Extractives from the Bark of Eupomatia laurina
Authors: Read RW , Taylor WC
Published: September 2010

A further extraction of the
bark of Eupomatia laurina R. Br.from North Queensland yielded 17 substances: liriodenine, norushinsunine, β-sitosterol, eupomatenoid-1,-7 and -8, (�)-trans-dehydrodiisoeugenol(2), eupolauridine,
eupolauramine and hydroxyeupolauramine,
together with the seven new substances, eupomatenoid-13, eupodienone-4, -5, -6
and -7, and EL-base-4 and -5.Eupomatenoid-13 was shown
to be 2-(4'-hydroxyphenyl)-7-methoxy-3-methyl-5-(E)-propenylbenzofuran
(1). Extraction of a sample of bark from
New Guinea yielded eupolauramine, hydroxyeupolauramine,
Β-sitosterol,
eupomatenoid-1, -2, -3 and -11, and eupodienone-1, -2, -3, -4, -5, -6 and -7.
17,18-Cyclo Steroids
Authors: Bogan P , Gall RE
Published: September 2010

3α-Acetoxy-5β-pregnan-20β-ol
(4a) has been converted into the iodo alcohol (6)
with lead tetraacetate and iodine. The derived iodo
ketone (7) gave good yields of 3α-acetoxy-17,18-cyclo-5β-
pregnan-20-one(8a) when treated immediately with potassium t-butoxide and t-butyl alcohol.
Quartz Ultraviolet Rydberg Transitions in Benzene Isomers
Authors: Harman PJ , Kent JE , O'Dwyer MF , Smith MH
Published: September 2010

Investigation of the matrix
isolation and high-pressure perturbation spectra of the benzene isomers,
benzvalene, Dewar benzene and fulvene, has shown conclusively that the
structured regions in the absorption spectra of these molecules around 200 nm
are due not to valence shell transitions but rather are Rydberg transitions to
3s type states. In the light of the experimental evidence reassignments of the
spectra of each of these molecules have been proposed.
Photochemical Formation of [3,3,2]Propellanes from 1,5-Dimethylenecycloalkanes
Authors: Bishop R , Landers AE
Published: September 2010

Photolysis of the dienes 10,13-imethylenetricyclo[6,3,3,02,7]tetradeca-2,4,6-triene
and 1,5-dimethylenecyclooctane results in cyclization to the corresponding
[3,3,2]propellane structure. The latter reaction
provides a convenient synthesis of [3,3,2]propellane
from cycloocta-1,5-diene. In contrast 2,6-dimethylenebicyclo[3,3,1]nonane is converted into
2-methyl-6-methylenebicyclo[3,3,1]non-2-ene under similar conditions.
Chemistry of the Podocarpaceae. LIV. Lignans from the Wood of Dacrydium intermedium
Authors: Cambie RC , Pang GTM , Parnell JC , Rodrigo R , Weston RJ
Published: September 2010

Structures and absolute
configurations are established for three new lignans isolated from the wood of
the New Zealand gymnosperm Dacrydium intermedium Kirk by preparative h.p.l.c.
of their acetates (1), (3) and (5). The 1H and 13C N.M.R.
spectra of phenyltetralin lactones and acetals are described.
Electrochemical Reduction of 7-Oxo Steroids: Route to Multideuterated Biological Steroids
Authors: Phillipou G , Seaborn CJ , Blair IA
Published: September 2010

Electrochemical reduction
of saturated 7-oxo steroids is shown to be an efficient procedure for the preparation
of the respective deoxygenated analogues. Use of deuterated reagents allows a
facile route to the corresponding deuterated steroids.
Determination of the equilibrium constants of water-methanol deuterium exchange reactions from vapour pressure measurements
Authors: Koner ZS , Phutela RC , Fenby DV
Published: September 2010

The equilibrium constant of
the reaction2CH3OH(l) + D2O(l)
→ 2CH3OD(l) + H2O(l)
is obtained from vapour
pressure measurements. The value, 1.09k0.02 at 298 K, is in satisfactory
agreement with calculated values and with calorimetric estimates. Vapour pressures at 298.14 K are reported for the systems H2O + CH3OH, H2O+CH3OD, D2O +
CH3OH and D2O+ CH3OD. Molar excess Gibbs functions are obtained from these vapour pressures.
Stereochemical studies. VI. Stereoselective synthesis of trans-fused octahydroindene-1-carboxylic acids
Authors: Galteri M , Lewis PH , Middleton S , Stock LE
Published: September 2010

The trans-fused
octahydroindene-1-carboxylic acid (9) having a pseudo- axial carboxyl group is
formed in good yield on oxidation of 2-acyl derivatives of trans-fused
octahydronaphthalen-1(2H)-one. On epimerization it yields the pseudo-equatorial
isomer (3) which is structurally related to the gibberellic acids.
Some ester derivatives of a 2-Methylalanine as intermediates in peptide synthesis
Authors: Stewart FHC
Published: September 2010

The o-nitrophenylthio
derivative of 2-methylalanine served as the precursor of several new ester
hydrochlorides, which have been investigated as intermediates for the synthesis
of peptides containing this amino acid. Particular consideration is given to the
effect of the steric hindrance associated with 2-methylalanine. Synthesis of a
2- methylalanyl analogue of the opiate agonist leucine-enkephalin is described.
(U0.7Y0.3)O2+x/YSZ interface
Authors: Badwal SPS
Published: September 2010

Complex impedance
measurements were made on (U0.7Y0.3)O2+x/YSZ/(U0.7Y0.3)O2+x
cells, both powder and dense disc electrodes being used. The depressed
electrode arcs have been fitted to a circuit (proposed previously) containing
frequency-dependent components. Surface roughness and the porosity of the
electrode have little effect on the angle of depression of the electrode arc. Instead,it is suggested that this behaviour is caused by multipaths in the overall charge-transfer reaction in which
more than one step dominates the rate process as the frequency is changed.
Alkaloids of Doryphora aromatica
Authors: Bick IC , Leo w , Richards M
Published: September 2010

The aporphine alkaloid
isocorydine (8) and six bisbenzylisoquinolines, daphnoline (1), homoaromoline (4),
daphnandrine (2), aromoline (3), isotetrandrine (6) and 1,2-dehydroapateline
(7) have been isolated from the north Queensland monimiaceous plant Doryphora
aromatica.
The Meisenheimer rearrangement in heterocyclic synthesis. I. Synthesis of some tetrahydro-2,3-benzoxazepines
Authors: Bremner JB , Browne EJ , Davies PE , Thuc LV
Published: September 2010

Melt pyrolysis of the
cis-6,7-dimethoxy-2-methyl-1-phenyl-1,2,3,4- tetrahydroisoquinoline
N-oxide (2b) afforded the Meisenheimer rearrangement
product, 7,8-dimethoxy-3-methyl-1-phenyl-1,3,4,5- tetrahydro-2,3-benzoxazepine
(5b), in good yield, as did pyrolysis of the corresponding trans-N-oxide (3b)
(in a melt) or a mixture of (2b) and (3b) (melt or in solution). The synthesis
of the 1-deuterated analogue, (5c), of (5b) is described, together with
products derived from (5b) by cleavage of the N-O bond which were used to
confirm its structure. Meisenheimer rearrangement of
the N-oxides (10) and (11) of 6,7-dimethoxy-1-(3,4-dimethoxyphenyl)-2-methyl-1,2,3,4-tetrahydroisoquinoline
and 2-methyl-1-phenyl-1,2,3,4- tetrahydroisoquinoline
gave the analogous 2,3-benzoxazepine derivatives (12) and (13), respectively.
A novel lipid from the brown alga Notheia anomala
Authors: Warren RG , Wells RJ , Blount JF
Published: September 2010

The brown alga Notheia anomala has yielded a C19
lipid diol,
(6S,7S,9R,10R)-6,9-epoxynonadec-18-ene-7,10-diol, as the major component. The
structure, assigned on the basis of spectral data, was confirmed by
single-crystal X-ray analysis, which also established the relative
stereochemistry. The absolute configuration was determined on the monoacetate by the Horeau method.
Syntheses of some constituents of Zingiber cassumunar
Authors: Tuntiwachwuttikul P , Limchawfar B , Reutrakul VPO , Kusamran K , Byrne LT
Published: September 2010

Syntheses of the aromatic
compounds cis-3-(2',4',5'-trimethoxyphenyl)- 4-[(E)-2''',4''',5'''-trimethoxy-styryl]cyclohex-1-ene
(1), cis-3-(3',4'- dimethoxyphenyl-4-[(E)-3''',4'''-dimethoxystyryl]cyclohex-1-ene(2),
cis-3-(3',4'-dimethoxyphenyl)-4-[(E)-2''',4''',5'''-trimethoxystyryl]cyclohex-1-ene
(3), (E)-4-(3',4'-dimethoxypheny1)but-3-en-1-ol (5), and (E)-4-
(3',4'-dimethoxyphenyl)but-3-enyl acetate (6) have been carried out.
Photobromination of carbohydrate derivatives. VI. Functionalization at C6 of 2,3,4-Tri-O-acetyl-1,6-anhydro-β-D-glucopyranose
Authors: Ferrier RJ , Furneaux RH
Published: September 2010

Photobromination of 2,3,4-tri-O-acetyl-1,6-anhydro-β-D-glucopyranose
gives the syrupy 6S (exo) bromide in high yield; further reaction leads to
secondary bromination at this position. The monobromide reacts with methanol
and thiophenol under conditions of kinetic control to give mainly the
endo-methoxy and -phenylthio derivatives formed by direct nucleophilic
displacement, and from the latter the exo-methoxy acetal was obtained by a
second nucleophilic substitution. Acetolysis of these
compounds can lead to the corresponding exo-6-acetoxy ester or monocyclic
products formed by opening of the five-membered rings.
Ion-cyclotron resonance studies of alkylsilyl ions. VI. The reactions of 2,2-dimethylpropan-1-ol and 1-methoxy-2,2-dimethylpropane with the trimethylsilyl cation
Authors: Trenerry VC , Blair IA , Bowie JH
Published: September 2010

The trimethylsilyl
cation forms 1 : 1 adducts with both 2,2- dimethylpropan-1-ol and 1-methoxy-2,2-dimethylpropane,
with both adducts eliminating C5H10 by (at least) two
mechanisms. One mechanism involves a 1,2-hydride transfer from the carbon
α to oxygen to the oxygen acceptor site; the other a 1,4-transfer from a
γ-carbon substituent.
Regio- and stereo-selectivity in the reactions of anions of aryl allyl sulfides with benzaldehyde
Authors: Ridley DDSMA
Published: September 2010

Addition reactions of
anions of aryl allyl sulfides to benzaldehyde proceed readily and in good
yields and afford mixtures of products resulting from α- and γ-attack
on the allyl anion. γ-Products pre- dominate, and the ratio of (E) : (Z)
isomers usually surrounds unity, although in the case of the reaction involving
3-(phenylthio)but-1-ene the ratio is 10 : 1. The ratio of diastereoisomers formed
in products resulting from α-attack ranges from 3 : 1 to 1.3 : 1 (starting
from 3- (2,4,6-trimethyl-phenylthio)prop-1-ene and 2-methyl-3-(phenylthio)prop-
1-ene respectively).
Chemical Constitution and Activity of Bipyridinium Herbicides. XIII. Synthesis, Reduction Potential and Biological Activity of 1-Methyl-4-[[(methylpyridinium-4-yl)Imino]methyl]pyridinium Diiodide
Authors: Rockley J , Summers L
Published: September 2010

A diquaternary salt from
the azomethine N-(pyridin-4- ylmethylene)pyridin-4-amine
has been prepared. The salt is slowly reduced by zinc dust in aqueous solution
to a red radical cation at a potential (E0) of -0.64 V in the pH
range 5.2-8.0. In keeping with its low reduction potential the salt is very
much less active than paraquat as a post-emergent herbicide.
The chemistry of Eremophila spp. XII. A new decipiene diterpene
Authors: Croft KD , Ghisalberti EL , Jefferies PR , Marshall DG , Raston CL , White AH
Published: September 2010

A new diterpene,
1,18-dihydroxydecipi-14-en-19-oic acid, has been isolated from an unclassified Eremophila sp. Chemical and X-ray diffraction evidence is
presented which confirms its structure and relative configuration.
Oxidations with lead tetraacetate. III. Oxidations of 2-substituted-1,3-benzodioxoles
Authors: Cole ER , Crank G , Minh HTH
Published: September 2010

Oxidation of 2-alkyl- and
2-aryl-1,3-benzodioxoles with lead tetraacetate gives products mainly derived
from cleavage of the dioxole ring. Formation of products is suggested to follow
initial attack and hydrogen abstraction at the 2-position of the benzodioxole.
Subsequent reactions then occur to give the observed products. The processes
are seen as free radical reactions.
Quinones and quinone methides. VII. Reactions of 1,4-naphthoquinone and 1,4-benzoquinones with 4-hydroxy-2H-1-benzopyran-2-one and 5,5-dimethylcyclohexane-1,3-dione in acid solutions
Authors: Jurd L
Published: September 2010

4-Hydroxy-2H-1-benzopyran-2-one
(4) reacts with 1,4-naphthoquinone, 2- methoxy-1,4-benzoquinone and
1,4-benzoquinone in aqueous acetic acid solutions to yield the quinone (6) and
the quinols (11)and (2), respectively. With 5,5-dimethylcyclohexane-1,3-dione,
1,4- naphthoquinone forms a bisfurano compound (9)
while 1,4-benzoquinone yields the bisfurano compound (18) and the monophenolic furano
derivative (17). The blue product formed by acid catalysed dimerization of
2-methoxy-1,4-benzoquinone forms a diacetate, the n.m.r. spectra of which is in
accord with structure (15b).
Energy gaps in organic semiconductors derived from electrochemical data
Authors: Lyons LE
Published: September 2010

The band gap, EG,
of an organic solid can be estimated by adding the magnitudes of oxidation and
reduction potentials of the compound in solution, plus a correction to the ion
solvation energy which allows for the different dielectric constants of solvent
and solid. Values of EG for 30 organic solids have been estimated. ��� The auto-ionization model, previously used for aromatic hydrocarbons, is applied to dyes and chlorophylls. The values of EG
are used to interpret various existing results on photoconduction and
semiconduction in dyes and chlorophylls.
The Kerr effect of amino acids in water
Authors: Khanarian G , Moore WJ
Published: September 2010

We report the Kerr effect
of 18 L-α-amino acids in dilute aqueous solution. From these data and dielectric
measurements reported in the literature we calculate the molar Kerr constants
and dipole moments of the amino acids in water, using the Onsager model for a
dielectric medium. We also deduce the components of the polarizability tensor
along the dipole moment and the sum of the components normal to it. We apply
the bond additivity approximation to deduce the conformations of the side chains
of the aliphatic amino acids, phenylalanine and histidine. A simple model is
presented that allows us to deduce the conformations of the side chains
independent of any assumptions about the dielectric model and the optical
anisotropy of the bonds of the side chains.
2-Phenylethylamides of a novel lipid acid; atrial stimulants from the soft coral Sinularia flexibilis
Authors: Kazlauskas R , Marwood JF , Wells RJ
Published: September 2010

Three amides derived from
tyramine, 4-(2-aminoethyl)-2-methoxyphenol and 5-(2-aminoethyl)-2-methoxyphenol
and a novel lipid acid, (Z)-3- methyldodec-2-enoic acid, were isolated from the
soft coral Sinularia flexibilis. The structures, obtained by spectral methods,
were confirmed by synthesis.
Multicomponent diffusion in dilute solutions of mixed electrolytes
Authors: Leaist DG , Lyons PA
Published: September 2010

The Onsager-Fuoss theory of
ion transport can be used to study multicomponent diffusion in dilute solutions
of mixed electrolytes. Precise Lij phenomenological coefficients can
be calculated from a knowledge of the solvent properties and limiting ionic conductivities.
If activity coefficients for dilute mixed electrolyte systems are available,
precise multicomponent diffusion coefficients can also be calculated. Explicit
equations are given for calculating both sets of transport coefficients. The
equations apply to systems containing an arbitrary number of strong
electrolytes and are valid at low total salt concentrations. To illustrate the
use of the equations, ternary diffusion in a few aqueous systems is examined in
detail. Aqueous mixed electrolyte systems containing H+ exhibit strongly
coupled diffusion and highly variable diffusion coefficients. A modified Harned
conductimetric experiment is described for the determination of ternary
diffusion coefficients in dilute solutions. Results for the system HCl- KCl-H2O
are in good agreement with theoretical predictions.
Osmotic coefficients and activity coefficients of aqueous mixtures of sodium chloride and sodium carbonate at 25°C
Authors: White Jr DR , Bates RG
Published: September 2010

Isopiestic vapour-pressure
measurements have been used to determine the osmotic coefficients of aqueous
mixtures of sodium chloride and sodium carbonate at 25°C. Solutions of sodium
chloride were used as the reference electrolyte. The data served to evaluate
the excess free energies of mixing as well as the mixing parameters of the
Scatchard and Pitzer theories. The three-parameter form of the Scatchard
equation accounts well for the experimental results, and the Pitzer equation with
two adjustable parameters does equally well. The activity coefficients of the
individual salts in the mixtures have been calculated.
Upper critical solution temperatures of perfluoro-n-hexane + alkane, sulfur hexafluoride + siloxane and perfluoropropane + siloxane mixtures
Authors: Waterson SD , Semmens J , Young CL
Published: September 2010

Upper critical solution
temperatures of perfluorohexane+alkanes (C5
to C18), sulfur hexafluoride+siloxanes (Si2
to Si8) and perfluoropropane+siloxanes (Si2
to Si8) mixtures are reported. In each of the three groups of
mixtures the phase behaviour type changes from type II to type III (in terms of
the Scott classification). The interaction parameters, ξ, calculated by
using the one-fluid model change more or less smoothly with increasing chain
length of the siloxane (or alkane) even when the phase behaviour type changes.
Excess volumes for ethanol + water mixtures at 10-K intervals from 278.15 to 338.15 K
Authors: Marsh KN , Richards AE
Published: September 2010

The excess volumes of
mixtures of xA ethanol+ xB water have been measured at
10-K intervals from 278.15 to 338.15 K over the whole composition range,
various dilution dilatometers being used. Particular attention has been paid to
regions dilute in both ethanol and water. The partial molar excess volume of
ethanol at infinite dilution in water is extremely temperature-dependent,
becoming more negative as the temperature increases. The partial molar excess
volume of ethanol in dilute solutions is very concentration-dependent at low
temperatures but the dependence approaches zero at 362 K. At an xA
value of 0.038, the partial molar excess volume of ethanol VEA
is independent of temperature, having a value of -5.23 cm3 mol-1,
while the excess volume VEA is independent of temperature
at xA = 0.082, having a value of -0.420 cm3 mol-1.
These unusual observations are explained in terms of the variation of the
temperature of maximum density with composition for dilute ethanol solutions.
At high mole fractions of ethanol the excess volume and the partial molar
excess volume of water do not show unusual behaviour.