The Manufacture of New Iron Compounds and their Application to the Preparation of Leather.
Year: 1897

page_text: PROVISIONAL SPECIFICATION.
The Manufacture of New Iron Compounds and their Application
to the Preparation of Leather.
JUDE ETIENNE CHEVALLOT, of 8, Rue Bérenger, Nanterre (Seine), in the
Republic of France, Chemist, do hereby declare the nature of this invention to
be as follows:-
My invention relates to a new complex ferric sulphate or series of sulphates
of decreasing intermediate oxidation, more particularly designed to be applied to
the manufacture of flexible or dressing leather.
From the chemical point of view, the distinctive characteristic of this sulphate
(or series of sulphates) is, that it is formed from a base brought to a lower degree
of oxidation than that of the persulphate, which comprises one equivalent and a
half of oxygen for one equivalent of metal. From the point of view of the results
obtained in its application to tanning, it is distinguished by its property of
producing flexible and hygroscopic leather, two qualities which enable it to be
softened, stuffed or nourished and curried, whilst the leather obtained by means
of persulphate is rigid and repels water, a double fault which prevents its coming
into use.
This new product comprises three degrees of intermediate oxidation, starting
from the magnetic oxide, which degrees are represented by the following formulæ,
indicating the proportion of the metal to its oxygen in the decreasing proportions
of 1 to 133; 1 to 1.25; and 1 to 1.20, viz.:—
From this it results that the oxygen of the base and that of the acid are in
the constant proportion of 1 to 3, a condition necessary for the solubility of the
salts.
The method of obtaining them in aqueous solution consists, in a general way,
of subjecting ferrous sulphate to the constant oxidizing action of an alkaline
bichromate or permanganate in presence of water to which is added a

page_text: predetermined quantity of sulphuric acid. In the reaction which takes place, the
bichromate, or the permanganate, is decomposed, one losing half of its oxygen to
reduce it to the state of sesquioxide of chromium, and the other five equivalents,
reducing it to the state of protoxide of manganese. Their oxygen in transferring
itself to the ferrous sulphate transforms it partially into ferric sulphate which
combines with the products of decomposition of the oxidizing agent employed.
To produce the magnetic sulphate, the reaction of the first substances is
effected according to the following equations, either by the action of bichromate
of potash, or by that of the permanganate of that base:
(Fe O, SO,, 7 HO), + (SO. HO), + KO, 2 Cr 03
(Fе 04, 4 SO), (Cr₂ O., 3 SO), (KO, SO₁) + 70 HO.
(Fe O, SO, 7 HO) 15 (SO, HO), + KO, Mn, O₁ =
(Fе, 04, 4 S03) 5, (Mn OS O3)2, (K O, SO₂) + 113 HO.
If similar equivalent quantities of acid and bichromate are allowed to act on
twelve equivalents of the ferrous salt, or of acid and permanganate on 20 equivalents,
the resulting action will produce ferric sulphate of a lower degree than Fe,О; if
finally the samo action takes place on 15 equivalents of bichromate or
25 equivalents of permanganate, the ferric salt of lower oxidation FeО is obtained,
thus proportionately increasing the quantities of protoxide sulphate of iron of three
or five equivalents without changing those of the reacting substances.
on
In translating the symbolic terms of the first member of an equation into their
equivalent number and dividing each of the two latter by the former, the quotient
obtained is the multiplicand of 1 kilogram of ferrous sulphate for determining
respectively the weights of the acid and of the oxidizing substances necessary for
the reaction to peroxidize the iron salt in the manner proposed.
These multiplicand quotients are the following, viz. :-

page_text: For making tanning baths, the following may be given as a specimen of one of
them, prépared with bichromate of potash for a medium oxidation represented by
the formula FeО, of a current application.
Water
Ferrous sulphate -
Sulphuric acid
Bichromate of potash
Sulphocyanide of potassium
100
30
litres.
kilograms.
6.750
2.640
0.045
The process of tannage consists in saturating the freshly unhaired hides or skins
in a solution of one of the ferric salts above mentioned, agitating them in one of
the moving apparatuses used in tanning and tawing. The operation lasts from 12
to 96 hours according to the thickness of the hides or skins. The suppleness and
the faculty of absorbing possessed by the leathers produced are greater
accordingly as the salt employed has been the less oxidized. They possess,
moreover, the important advantage of being preserved from mycelium fermentation
or mould when in damp situations.
Deted the 8th day of June 1897.
to the Preparation of Leather.
I, JUDE ETIENNE CHEVALLOT, of 8, Rue Bérenger, Nanterre (Seine), in the
Republic of France, Chemist, do hereby declare the nature of this invention and
in what manner the same is to be performed, to be particularly described and
ascertained in and by the following statement :—
My invention relates to a new complex ferric sulphate or series of sulphates of
decreasing intermediate oxidation, more particularly designed to be applied to the
manufacture of flexible or "dressing" leather.
From the chemical point of view, the distinctive characteristic of this sulphate
(or series of sulphates) is, that it is formed from a base brought to a lower degree
of oxidation than that of the persulphate, which comprises one equivalent and a
half of oxygen for one equivalent of metal. From the point of view of the results
obtained in its application to tanning, it is distinguished by its property of
producing flexible and hygroscopic leather, two qualities which enable it to be
softened, stuffed or nourished and curried, whilst the leather obtained by means of
persulphate is rigid and repels water, a double fault which prevents its coming into
use.
This new product comprises three degrees of intermediate oxidation, starting
from the magnetic oxide, which degrees are represented by the following formula
indicating the proportion of the metal to its oxygen in the decreasing proportions of
1 to 1.33; 1 to 1.25 and 1 to 1.20, viz. :

page_text: From this it results that the oxygen of the base and that of the acid are in the
constant proportion of 1 to 3, a condition necessary for the solubility of the salts.
The method of obtaining thein in aqueous solution consists, in a general way, of
subjecting ferrous sulphate to the constant oxidizing action of an alkaline
bichromate or permanganate in presence of water to which is added a predetermined
quantity of sulphuric acid. In the reaction which takes place, the bichromate or
the permanganate, is decomposed, one losing half of its oxygen to reduce it to the
state of sesquioxide of chromium, and the other five equivalents, reducing it to
the state of protoxide of manganese. Their oxygen in transferring itself to the
ferrous sulphate transforms it partially into ferric sulphate which combines with
the products of decomposition of the oxidizing agent employed.
To produce the magnetic sulphate, the reaction of the first substances is effected
according to the following equations, either by the action of bichromate of potash,
or by that of the permanganate of that base:
(Fe O, SO, 7 HO), + (SO, HO), + KO, 2 Cr Q₂ =
(FeO 4 SO) + (Cr, O,, 3 SO₁) + (KO, SO₂) + 70 HO.
(Fe O, SO3, 7 HO) + (SO, HO), + KO, Mn, Or
(Fʊ²Û¸ 4 803)5 † (Mn ✪, SÛ₂), † (ÃÛ, DÛ³) + 115 10.
=
* DV3/5 T [MIM U, DUg), T (AV, DU₂) +
If similar equivalent quantities of acid and bichromate are allowed to act on
twelve equivalents of the ferrous salt, or of acid and permanganate on 20
equivalents, the resulting action will produce ferric sulphate of a lower degree
than Fe05; if finally the same action takes place on 15 equivalents of bichromate
or on 25 equivalents of permanganate, the ferric salt of lower oxidation FeО is
obtained, thus proportionately increasing the quantities of protoxide sulphate of
irun of three or five equivalents without changing those of the reacting substances.
1. translating the symbolic terms of the first member of an equation into their
equiv. lent number and dividing each of the two latter by the former, the quotient
obtained is the multiplicand of 1 kilogram of ferrous sulphate for determining
respectively the weights of the acid and of the oxidixing substances necessary for
the reaction to peroxidize the iron salt in the manner proposed.
These multiplicand quotients are the following viz. :

page_text: original strength, it is done by the addition of the same substances according to
their chemical equivalents proceeding as above mentioned.
For making tanning baths, the following may be given as a specimen of one of
them, prepared with bichromate of potash for a medium oxidation represented by
the formula Fe, О of a current application.
original strength, it is done by the addition of the same substances according to
their chemical equivalents proceeding as above mentioned.
For making tanning baths, the following may be given as a specimen of one of
them, prepared with bichromate of potash for a medium oxidation represented by
the formula Fе, О of a current application.
Water
Ferrous sulphate
Sulphuric acid
Bichromate of potash
Sulphocyanide of potassium -
100 litres.
30 kilograms.
6.750
"
2.640
"
-
0.045
"
The process of tannage consists in saturating the freshly unhaired hides or skins
in a solution of one of the ferric salts above described, agitating them in the
moving apparatuses used in tanning and tawing. The operation lasts from 12
to 96 hours according to the thickness of the hides or skins. The suppleness and
the faculty of absorbing possessed by the leathers produced are greater accordingly
as the salt employed has been the less oxidized. They possess, moreover, the
important advantage of being preserved from mycelium fermentation or mould
when in damp situations.
Having now particularly described and ascertained the nature of my said
invention, and in what manner the same is to be performed, I declare that what
I claim is :-
1. The manufacture of the herein described complex ferric sulphate, regarded as
an uncrystallizable combination of sesquioxide and protoxide of iron in various
proportions united with the products of decomposition of the oxidizing bodies
whereby it is formed, substantially as set forth.
"
2. The herein described compound in all its degrees of intermediate oxidation.
3. The application of the compound herein described to the manufacture of
dressing "leather or flexible leather, substantially as hereinbefore described.
Dated the 22nd day of Tohruann 1900
D. YOUNG & Co.,
11 and 12, Southampton Buildings, London, W.C.,
Agents for the Applicant.