IMPROVEMENTS IN THE MANUFACTURE OF CERTAIN COAL TAR AND RESIDUAL PRODUCTS
Year: 1880

page_text: LETTERS PATENT to Charles Lowe and John Gill, both of Manchester, in
the County of Lancaster, Manufacturing Chemists, for an Invention of
"IMPROVEMENTS IN THE MANUFACTURE OF CERTAIN COAL TAR AND RESIDUAL
PRODUCTS."
PROVISIONAL SPECIFICATION left by the said Charles Lowe and John
Gill at the Office of the Commissioners of Patents on the 9th April 1880.
CHARLES LOWE and JOHN GILL, both of Manchester, in the County of Lancaster,
Manufacturing Chemists. "IMPROVEMENTS IN THE MANUFACTURE OF CERTAIN
COAL TAR AND RESIDUAL PRODUCTS."
The object of our Invention is,—
Firstly. To effect novel and economical improvements in the separation of the
crude tar acids, carbolic, cresyllic acids, and their homologues contained in the
alkaline solutions obtained by washing with solutions or hydrated mixtures of
potash, soda, or lime by well known methods, the light or heavy oils obtained by
the distillation of coal tar, and
Secondly. The production and utilization of residual or bye products having
greater commercial value than the residual or bye products obtained by the
application of the well known incthods now in use for the separation of the said
crude tar acids from their alkaline solutions.
To carry these objects into effect, and in substitution for the sulphuric or hydro
chloric acids hitherto used, we cause to pass through, over, or mix with the said
alkaline solutions (of the crude tar acids, carbolic, cresyllic acids, or their homologues
contained in, and by means of any suitable apparatus,) a current of sulphurous acid
until sufficient saturation of the potash, soda, or lime of the said alkaline solutions
is effected, which may be recognised by the complete separation of the said alkaline
solutions into two layers, the one a dark coloured oily layer, consisting of the crude
tar acids, which merely requires clarification by settling to render it fit for the
market, and the other a watery solution of the neutral or acid sulphites of potash,
soda, or lime formed by the combination of the sulphurous acid with the base of
the said alkaline solutions of the crude tar acids. The saturation by sulphurous
acid of the base of the said alkaline solutions of the crude tar acids, carbolic,

page_text: cresyllic, or their homologues, we carry either to the point of neutrality only, or to
any further degree of saturation that may be required in excess of this point in
order to form mixed or acid sulphites. The watery solution of the neutral or acid
sulphites of potash, soda, or lime, prepared in the manner above described, we
utilize in three different ways:—
Firstly. As a direct source of sulphurous acid for disinfecting, bleaching, or other
purposes, by simple admixture with a cheap mineral acid, such as sulphuric or hydro
chloric acids.
Secondly. By abstraction from it of the excess of water present, by any of the
well known processes employed for similar purposes, we convert it into crystallized
or dry neutral or acid sulphites of potash, soda, or lime suitable for the market.
Thirdly. By admixture of the said crystallized or dry neutral or acid sulphites
of potash, soda, or lime, obtained as above described,-and-the-crude_tar_acids,
likewise obtained as herein described, by separation by sulphurous acid from their
alkaline solutions with silica, or china clays, or sulphate of lime or iron to form
disinfecting powders, which, on the addition of a cheap mineral acid, are capable
of evolving in the state of gas or vapour both sulphurous and the tar acids.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Charles Lowe and John Gill in the Great Seal Patent Office on
the 7th October 1880.
CHARLES LOWE and JOHN GILL, both of Manchester, in the County of Lancaster,
Manufacturing Chemists. IMPROVEMENTS IN THE MANUFACTURE OF CERTAIN
1
COAL TAR AND RESIDUAL PRODUCTS."
The object of our Invention is,—
Firstly. To effect novel and economical improvements in the separation of the
crude tar acids, carbolic, cresyllic acids, and their homologues contained in the
alkaline solutions obtained by washing with solutions or hydrated mixtures of
potash, soda, or lime by well known methods, the light or heavy oils obtained by
the distillation of coal tar, and
Secondly. The production and utilization of residual or bye products having
greater commercial value than the residual or bye products obtained by the
application of the well known methods now in use for the separation of the said
crude tar acids from their alkaline solutions.
To carry these objects into effect, and in substitution for the sulphuric or hydro-
chloric acids hitherto used, we cause to pass through, over, or mix with the said
alkaline solutions (of the crude tar acids, carbolic, cresyllic acids, or their homologues
contained in, and by means of any suitable apparatus,) a current of sulphurous acid
until sufficient saturation of the potash, soda, or lime of the said alkaline solutions
is effected, which may be recognised by the complete separation of the said alkaline
solutions into two layers, the one a dark coloured oily layer, consisting of the crude
tar acids, which merely requires clarification by settling to render it fit for the
market, and the other a watery solution of the neutral or acid sulphites of potash,
soda, or lime formed by the combination of the sulphurous acid with the base of
the said alkaline solutions of the crude tar acids. The saturation by sulphurous
acid of the base of the said alkaline solutions of the crude tar acids, carbolic,
cresyllic, or their homologues, we carry either to the point of neutrality only, or to
any further degree of saturation that inay be required in excess of this point in
order to form mixed or acid sulphites.
The watery solution of the neutral or acid sulphites of potash, soda, or limo,
prepared in the manner above described, we utilize in three different ways:-
Firstly. As a direct source of sulphurous acid for disinfecting, bleaching, or other
purposes by simple admixture with a cheap mineral acid, such as sulphuric or hydro-
chloric acids.
Secondly. By abstraction from it of the excess of water present, by any of the
well known processes employed for similar purposes, we convert it into crystallized
or dry neutral or acid sulphites of potash, soda, or lime suitable for the market.
Thirdly. By admixture of the said crystallized or dry neutral or acid sulphites
of potash, soda, or lime, obtained as above described, and the crude tar acids,
likewise obtained as herein described, by separation by sulphurous acid from their
alkaline solutions with silica, or china clays, or sulphate of lime or iron to form
disinfecting powders, which, on the addition of a cheap mineral acid, aro capable of
evolving in the state of gas or vapour both sulphurous and the tar acids.
Having stated the nature of our Invention and described the manner of effecting
the same, we declare that we claim,―
1. The novel and economical substitution of sulphurous acid for the sulphuric
and hydro-chloric acids hitherto employed for the separation of the crude tar acids,
carbolic, cresyllic, and their homologues, from their alkaline solutions, prepared in
the usual manner by washing the light and heavy oils obtained by distilling coal
tar with solutions or hydrated mixtures of potash, soda, or lime.

page_text: 2. The production and application, by the process herein described, of residual or
bye products, namely, sulphites of potash, soda, or lime, of greater market value
than the residual or bye products, namely, sulphates or chlorides of potash, soda, or
line, obtained in the process hitherto employed for the separation of the crude tar
acids, carbolic, cresyllic, and their homologues, from their alkaline solutions prepared
in the usual manner by washing with solutions or hydrated mixtures of potash,
soda, or lime, the light or heavy oils obtained by distilling coal tar, and
3. The application of the crystallized or dry neutral or acid sulphites of potash,
soda, or line, obtained as residual or bye products in the manner above described,
in combination with the crude tar acids (carbolic, cresyllic, and their homologues
separated by sulphurous acid from their alkaline solutions) and silica, china clay,
-sulphates of lime and iron to form disinfecting powders, which, on the addition of
a cheap mineral acid, are capable-of-evolving in the state of gas or vapour both
the sulphurous and the tar acids.
In witness whereof, I, the said Charles Lowe, for myself and on behalf of
the said John Gill, have hereunto set my hand and seal, this Fifth day
of October. One thousand eight hundred and eighty.