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Inorganic Redoxites.

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acid at 110 OC of o-(P-pheny1ethylmercapto)benzoicacid (11),
which is obtained by treatment of the sodium salt of methyl
thiosalicylate with P-phenylethyl bromide in boiling methanol,
followed by hydrolysis (m.p. 123 'C; yield: 85 %, based on
methyl thiosalicylate). I is also obtained in 45 % yield by
cyclisation of o-(phenylethy1mercapto)benzoyl chloride (b. p.
191-196 '(70.2 mm, obtained by treatment of I1 with thionyl
chloride) with aluminium chloride in a carbon disulfidenitrobenzene mixture.
The action of polyphosphoric acid on o-(P-phenyl-mercaptoethy1)benzoic acid - an isomer of I1 - affords only a 10 %
yield of I. This is remarkable, because ring systems containing one niethylene group less, viz. 6.1 1-dihydro[b,e]thiepin-11-one [l-31 or -oxepin-11-one [l] are produced in
80-90 % yield by cyclising o-(phenylmercaptomethy1)- or
o-(phenoxymethy1)-benzoic acid or their derivatives, respectively.
Reaction of I with Grignard reagents, e . g .
CIMg(CH2)3N(CH3)2, in tetrahydrofuran produces, as in
the cyclooctene [I c], thiepine [l c, 2,3], and oxepine series
[lc], the corresponding carbinol (m.p. 138.5 - 140 OC;
93 %), which is convertible by dehydration (e.g. with alcoholic hydrochloric acid) into 12-(3-dimethylaminopropylidene)-7.12-dihydro-6H-dibenzo[b,e]thiocine(b.p. 184-185 "C/
0.3 mm; 83 %I.
Received, August 31st. 1962
[Z 334/165
IE]
[I] a) K . Stach and H. Spingler, Angew. Chem. 74, 31 (1962).
b) K . Stuch and H . Spingler, Monatsh. Chem., in press; c) K .
Stach and F. Bickelhaupt, Monatsh. Chem., in press.
[2] M . Protiva, M . RajSner, V . Seidlovri, E. Adlerovri, and Z . J.
Vejdglek, Experentia 18, 326 (1962).
[3] Sandoz, Belg. Pat. 607503 (Aug. 24th, 1961; published,
Febr. 26th, 1962).
Inorganic Redoxites [*]
By Dr. B. Sansoni and DipLChem. 0. Sigmund
Chemisches Institut der Universitat Marburg/L. (Germany)
As the first purely inorganic counterpart to organic redox
resins the clay mineral Nontronit [l] was examined [2].
Aluminium in the rigid double-octahedron layers is partially
554
and isomorphously replaced by Fe2+/3+ ions. These are
capable, according to Weiss and Hofmann [3], of being
partially reduced or oxidised by sulphite or hydrogen
peroxide, respectively. This is therefore a redox ite according
to OUT definition [4].
Brittle, friable, greenish yellow aggregates from the pit at
Ficht/Opf. (Germany) were crushed, screened to 0.5-0.6 mm
and washed. Analysis: 3.83 % FezO3; 94.8 % Si02; about
1.1 % CaO and 0.6 % MgO; traces of AP+, K+, CI-. According to Debye-Scherrer diagrams the substance contains
large amounts of quartz. After reduction with aqueous
dithionite solution it is dark green, after oxidation with
highly dilute H202 it is honey yellow. The reflection spectra
of both forms show weakly marked bands, which correspond
approximately to solid Fe(I1) or Fe(II1) sulphate.
The redox capacity determined with a 0.2 M solution of
Fe(I1) sulphate in 0.01 N sulphuric acid is 0.16 mequiv./g or
0.19 mequiv./ml, corresponding to about 1/3 of the total iron.
It strongly decreases during five successive reductions and
oxidations owing to the partial extraction of the iron. By
potentiometric titration with a 0.1 N solution of titanium(II1)
chloride and ceric(1V) sulfate in 1 N H2SO4 the E50 %-potential was found to be 654 f 10 mV, i.e. about 27 mV lower
than the potential of Fe2+/3+ in the same solution. A third
method gave somewhat higher values [5]. During the determination slight decomposition occurs.
The exchange capacity of the reduced form for anions is
< 0.005 mequiv. Cl-/g. The exchange capacity for cations
(about 0.085 mequiv. 60Co2+/g)is approximately the same for
both the reduced and the oxidized forms. The low exchange
capacity of the Fe3+ form for anions is surprising: it is
< 0.005 mequiv. Cl-/g, 0.00004 mequiv. 131J-/g (partially
bound as IZ?) and 0.000009 mequiv. 87Br-/g [51.
Advantages as compared with organic redox resins are the
absence of irreversible oxidations, a relatively high reduction
rate (no gel diffusion), high temperature and radiation
stability; basic disadvantages are inferior redox capacity and
instability in strongly acidic or alkaline solution.
As further redoxites sodium polyvanadate and silicic acid
phenolic esters are being studied. The latter can be reduced
and oxidized on the surface in water free solvents 161.
Crystalline ammonium phosphomolybdate was reduced in
benzene by phenylhydrazine to a deep blue form, without
molybdenum blue going into solution,and was then reoxidized.
Received, August
6th, 1962
[Z 324/158 IE]
[*I XIIth Communication on "Redox-Exchangers".
[l] K. Jasmund: Die silikatischen Tonminerale. 2nd ed., Verlag
Chemie, Weinheim/Bergstr. 1955, p. 122.
[2] B. Sansoni, Lecture, GDCh-Hauptversammlung Stuttgart
(Germany) 1960; prediction of inorganic redoxites: lecture, Institute of Technology, Stockholm (Sweden) 1957.
[3] A . Weiss, U.Hofmann et al., Ber. dtsch. keram. Ges. 31, 301
(1954); Z. anorgan. allg. Chem. 284, 247 (1956).
[4]B. Snnsoni, Naturwissenschaften39,281 (1952); Ph. D. Thesis,
University Munich (Germany) 1956; Chem. Technik 10, 580
(1958).
[5] For a discussion of error see full publication.
[6] B. Sansoni and W . Schmidt, AbschluBarbeit, Regensburg 1953.
Angew. Chern. internat. Edit. / Vol. I (1962) / No. I0
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