A NEW OR IMPROVED METHOD OF UTILISING WASTE LIQUIDS CONTAINING ANILINE FOR THE PRODUCTION OF COLOURING MATTERS be as follows:- و
Year: 1884

page_text: I FRANK WIRTH, of the firm of Wirth and Company, Patent Solicitors at
Frankfort-on-the-Main, in the Empire of Germany do hereby declare the nature
of the said invention for "A NEW OR IMPROVED METHOD OF UTILISING WASTE
LIQUIDS CONTAINING ANILINE FOR THE PRODUCTION OF COLOURING MATTERS
be as follows:-
و"
to
This Invention relates to the utilization of liquids containing aniline, especially
the waste waters from aniline and aniline dye works.
The aniline contained in the watery liquids arising out of the manufacture of
aniline and the production of dyes, cannot be completely removed by the distillation
process which is the one almost universally employed up to the present; a portion,
not inconsiderable when the large quantity of water flowing away daily is taken
into account, remains in solution and is lost.
The object of this Invention is the formation in the said liquids, by suitable
reagents, of compounds, of Anilin, Toluidin &c which are insoluble or with difficulty
soluble in water; and by working these, whilst avoiding the recovery of the
aniline as such,-into useful coloring matters to produce a new industrial method
of utilizing liquids containing aniline, especially the waste waters.
To attain this end I use the following method of treatment with sodium nitrite
and hydrochloric acid, which forms soluble diazobenzol salts which by combination
with phenolic bodies produce insoluble or hardly soluble precipitates of the aniline
contained in the water.
°
To a measured quantity of waste water, acidified with about 1% of hydrochloric
acid. I add a dilute solution of nitrite of known strength until a portion of the
liquid causes iodide of potassium and starch to turn blue after standing some time.
The liquid thus treated is poured into a dilute solution of beta naphthol until an
alkaline portion of the filtrate no longer gives a precipitate with the former, shewing
that all the naphthol is absorbed. I find, thus, how much nitrate and naphthol
will be required for a given portion of the waste liquid. This experiment is based

page_text: upon the property of the beta-naphtholazo-benzols, as yet not described, of separating
even from very dilute alkaline liquids, being thus distinguished from the alpha-
naphtholazobenzol of Typke (Rep. Chem. Soc. Berl X 1576) which is soluble in
alkalies. In treating large quantities, the necessary amount of nitrite is added to
the liquid acidified as above and this, when the effect is finished, is mixed with the
corresponding amount of beta-naphthol containing excess of alkali. When the
naphthol compound is formed the liquid is acidified again to render filtration easy
and to dissolve lime hydrate which may have been precipitated if the waters
contained lime salts; the orange colored precipitate is collected on a filter.
If the beta-naphthol be replaced by alpha-naphthol the precipitate obtained
under the same conditions on the addition of acid has a dark brown color; in
both cases the aniline is completely separated even from the most dilute solutions.
If the beta-naphthol be replaced by its molecular equivalent of phenol the well
known oxyazobenzol is formed, but the separation of the aniline by acidifying the
liquid is not perfect on account of the partial solubility of the compound in water.
The separation is, however, nearly complete as is also the case if instead of
naphthols their Schaeffer monosulphoacids are employed. The combinations of the
latter with diazobenzol have also been described (Proc. Berl. Chem. Soc. X 1380
XI 2197). The processes connected with it which have been replaced in practice
by the manufacturing methods derived from the sulphanil acids have a special
value if, with them, instead of commercial aniline the waste waters hitherto lost
unused are employed, to which this Invention exclusively refers.
The separation of the azobenzolnaphtholsulphoacids thus obtained from the waste
waters is also effected by the addition of acid; the pressed precipitate is then again
treated with alkali.
Betanaphtholazobenzol can also be sulphonised by warming gently at a
temperature below 100° centigrade with 4 parts of concentrated or 3 parts of
concentrated and 1 of fuming sulphuric acid, without that the naphthol enters
on a further decomposition (as was observed by Typke for alpha compounds.)
There are thus obtained by the usual further treatment sodium salts soluble in
water which, so far as the ẞ compound is concerned, may, in many cases, serve as
a cheap substitute for the orange II obtained from the sulphoanil-acids of commerce,
whilst the so obtained alpha body is distinguished practically from the corresponding
orange I by its giving a chestnut brown changing to violet with alkalies; the
orange I gives a much brighter orange.

page_text: -
I, FRANK WIRTH, of the firm of Wirth and Company, Patent Solicitors, at
Frankfort on the - Main, Germany, do hereby declare the nature of the said
invention for "A NEW OR IMPROVED METHOD OF UTILISING WASTE LIQUIDS
CONTAINING ANILINE FOR THE PRODUCTION OF COLOURING MATTERS," and in what
manner the same is to be performed, to be particularly described and ascertained
in and by the following statement :—
This Invention relates to the utilization of liquids containing aniline especially
the waste waters from aniline and aniline dye works.
The aniline contained in the watery liquids arising out of the manufacture of
aniline and the production of dyes, cannot be completely removed by the distillation
process which is the one almost universally employed up to the present; a small
portion yet not inconsiderable when the large quantity of water flowing away
daily is taken into account, remains in solution and is lost.
The object of this Invention is the formation in the said liquids, by suitable
reagents, of compounds, of Aniline, Toluidin &c which are insoluble or with
difficulty soulble in water; and by working these, whilst avoiding the recovery
of the aniline as such,-into useful coloring matters to produce a new industrial
method of utilizing liquids containing aniline, especially the waste waters.
To attain this end I use the following method of treating the said liquids with
sodium nitrite and hydrochloric acid, which forms soluble diazobenzol salts which
by combination with bodies of the phenol series produce insoluble or hardly soluble
precipitates of the aniline contained in the waters.
°
To a measured quantity of waste water, acidified with about 1% of hydrochloric
acid, I add a dilute solution of nitrite of known strength until a portion of the
liquid causes iodide of potassium and starch to turn blue after standing some time.
Some of the liquid thus treated is slowly poured into a dilute solution of beta
naphthol until an alkaline portion of the filtrate no longer gives a precipitate with
the former, shewing that all the naphthol is absorbed. I find, thus, how much
nitrite and naphthol will be required for a given portion of the waste liquid. This
experiment is based upon the property of the beta-naphtholazo-benzol, of separating
even from very dilute alkaline liquids, being thus distinguished from the alpha-
naphtholazobenzol of Typke (Rep. Chem. Soc. Berl X 1576) which is soluble in
alkalies. In treating large quantities, the necessary amount of nitrite is added to
the liquid acidified as above and this, when the effect is finished, is mixed with the
corresponding amount of beta-naphthol containing excess of alkali. When the
naphthol compound is formed the liquid is acidified again to render filtration easy
and to dissolve lime hydrate which may have been precipitated if the waters
contained lime salts; the orange colored precipitate is collected on filters.
If the beta-naphthol be replaced by the alpha-naphthol the precipitate obtained
under the same conditions on the addition of acid has a dark brown color; in both
cases the aniline is completely separated even from the most dilute solutions. If
the beta-naphthol be replaced by its molecular equivalent of phenol the well known
oxyazobenzol is formed, but the separation of the aniline by acidifying the liquid
is not perfect on account of the partial solubility of the compound in water. The
separation is, however, nearly complete as is also the case if instead of naphthols
their Schaeffer monosulphoacids are employed. The combinations of the latter
with diazobenzol have also been described (Proc. Berl. Chem. Soc. X 1380 XI 2197).
The processes connected with it which have been replaced in practice by the
manufacturing methods derived from the sulphanil acids yet possess a special

page_text: value if, with them, instead of commercial aniline the waste waters hitherto lost
unused are employed, to which this Invention exclusively refers in this case.
The separation of the azobenzolnaphtholsulphoacids thus obtained from the waste
waters is also effected by the addition of acids; the pressed precipitate is then
again treated with alkali to form the soluble sodium salt.
The naphtholazobenzols can also be sulphonized by warming gently at a
temperature below 100° centigrade with 4 parts of concentrated or better 3 parts
of concentrated and 1 part of fuming sulphuric acid, without that the naphthol
compound enters on a further decomposition as was observed by Typke (loco
citato) for the alpha compound; the whole of the colouring matter is then by the
usual further treatment with alkali to be transformed into a sodium salt soluble in
water which, so far as the ẞ compound is concerned, may, in many cases, serve
as a cheap substitute for the orange II of commerce obtained from the sulphoanil-
acids, whilst the so obtained 'alpha body is distinguished practically from the
corresponding orange I by its giving a chestnut brown color changing to violet
with alkalies, the orange I gives a much brighter orange.
Having now particularly described and ascertained the nature of the said
Invention, and in what manner the same is to be performed, I declare that what
I claim is :-
The new or improved method of utilising watery liquids arising out of the
manufacture of aniline and aniline dyes especially the waste waters thereof by
treatment with nitrous acid and combination with alpha and beta naphthol phenol
and Schaeffers naphthol sulphoacids and sulphonation of the products of alpha and
beta naphthol substantially as described.
Dated this 31st day of October 1884.
FRANK WIRTH.
By his Agents,
A. M. & W
Clark,
53, Chancery Lane, W.C.