Manufacture of Derivatives of Para-Amido-Alpha-Naphthol and of Colouring-Matters derived from them.
Year: 1896

page_text: Date of Application, 18th Sept., 1896
Complete Specification Left, 8th June, 1897-Accepted, 17th July, 1897
Manufacture of Derivatives of Para-Amido-Alpha-Naphthol and of
Colouring-Matters derived from them.
I, OTTO NICHOLAS WITT, of Lindenallée 33, Westend, Bei Berlin, Germany,
Doctor of Philosophy, do hereby declare the nature of this invention to be as
follows:-
In para-amido-alpha-naphthol the hydrogen of both the amido and the hydroxyl-
groups is susceptible of being replaced by acid radicles, but no means have as yet
been known of limiting the reaction to only one of these groups. Grandmougin and
Michel, who have studied the reaction of acetic anhydride on para-amido-alpha-
naphthol (Berichte d. d. Chem Gesellschaft, XXV., p. 978) distinctly state, that
di-acetyl-para-amido-naphthol is the only product formed in this reaction, a well
crystallised compound melting at 158° C. I have discovered, that, contrary to these
observations, the amido-group only may be acetylised under certain conditions which
I have ascertained. The substance so obtained and which has its hydroxyl-group
intact, shows great similarity of behaviour to the phenols in general and the naphthols
in particular. I therefore propose to call this substance naphthacetol, indicating thus
its relation to the naphthols.
Naphthacetol is formed, if para-amido-alpha-naphthol hydrochloride be reacted
upon, in the presence of dry sodium acetate with no more than one molecule of acetic
anhydride, diluted by some suitable solvent, or if the above mentioned di-acetyl-
para-amido-naphthol of the melting point 158° C. be heated with caustic alkali until
complete solution takes place.
In the first of these processes of formation the amido group only is attacked, while
the hydroxyl group is not acted upon, in the second the acetyl group is removed from
the hydroxyl group only, while it remains intact in the amido group. On both these
reactions a process for the manufacture of naphthacetol may be based.
To obtain naphthacetol by the first method I proceed as follows:-
I mix 10 parts by weight of dry para-amido-alpha-naphthol with 5 parts of dry
sodium acetate in a suitable vessel of enamelled cast iron or porcelain, taking care
that both these ingredients are in a finely powdered condition.
The
To this mixture I add 5 parts, by weight, of acetic anhydride, previously diluted
with 10 parts of glacial acetic acid. On stirring the mixture, heat is generated
spontaneously and the mixture assumes the condition of a thin paste. If water be
added in this stage, the naphthacetol separates out. I prefer however to distil off the
acetic acid added as a solvent together with the acid formed in the reaction and thus
to recover it for further use. It is preferable to effect this distillation in vacuo.
residue from it is a mixture of naphthacetol with sodium chloride and acetate, from
which the former may be obtained by washing with water. It may then be
recrystallised either from boiling water in which it is sparingly soluble or from spirit
in which it dissolves plentifully on the water-bath, setting out in fine woolly needles
on cooling. Pure naphthacetol has its melting point at 187° C., it is easily soluble in
caustic alkalies without decomposition.

page_text: If, by some inistake, too much acetic anhydride has been used in the preparation of
naphthacetol, the above mentioned diacetate of the melting point 157° may be
formed.
In this case, as well as in any other, when it may be necessary to transform this
diacetate into naphthacetol, this may easily be effected by mixing it with so much
of a strong solution of caustic soda or potash, that a thin paste is formed. On
heating this on the water-bath, gradual solution takes place.
As soon as all is dissolved the formation of naphthacetol is completed. It may
then be precipitated from the mixture by the addition of an acid.
Congeners of naphthacetol, which in their properties closely resemble the latter,
may easily be obtained by substituting, in the process set forth, for acetic anhydride,
the anhydrides of other organic acids. Thus by reacting upon a mixture of 3 parts
para-amido-alpha-naphthol hydrochloride with 2.3 parts of butyric anhydride the
mono-butyryl derivative of paramidonaphthol may be obtained, which has its melting
point at 160-161° C. If, instead of butyric anhydride, 27 parts of valerianic
anhydride be used, the mono-valerianyl derivative is obtained, which melts at
204-205° C. By using 3 parts of benzoic anhydride the monobenzoyl derivative is
produced, melting at 228-229° C. *
All these substances form colourless glistening needles if recrystallised from
alcohol.
It has already been said, that naphthacetol closely resembles the naphthols in its
chemical behaviour.
This resemblance is also shown by the fact, that naphthacetol is easily acted upon
by diazo-compounds and that true azo-colouring-matters are formed in this reaction.
This property of naphthacetol may be utilised industrially in various ways of which
the following are examples:
(1). If cotton cloth or any other suitable woven material be impregnated with a
solution of naphthacetol, to which some sodium carbonate may advantageously be
added, and dried, then coloured patterns may be obtained on | such materials by
printing upon them with thickened solutions of diazo compounds, in a manner
exactly similar to the process now largely in use for materials impregnated with
solutions of the two naphthols.
The shades obtained from naphthacetol by this process differ considerably from
those obtained by the same diazo-compounds from either Beta or alpha naphthol, so
that by the introduction of naphthacetol the number of shades obtained by this
direct printing process is considerably increased. Thus for instance, naphthacetol
yields, if printed upon with the diazoderivative of
Aniline, a bright scarlet,
Pseudocumidin, a fine rose,
Alphanaphthylamine a purplish red
Betanaphthylamine, a rich claret,
Benzidine, a reddish purple,
Tolidine, a bluish purple
Dianisidine, a blue.
Other bases may be used in like manner with corresponding effects.
2. Instead of forming the azo dye on the material as above described, it may also
be prepared separately and then used for dyeing and calico-printing. Though the
azo-colours, the formation of which has been described above may be used for such
purposes, if prepared independently from the fibre, it will be generally found better
to use the diazo-compounds of sulphonated bases, which yield dye-stuffs of greater
solubility. Thus, for instance, diazobenzol-sulphonic acid, if acting upon
naphthacetol, yields a bright scarlet. With the diazoderivative of naphthionic acid a
reddish purple is obtained which is admirably suited to wool dyeing. The diazo-
hthalmine aninh….

page_text: colour, whilst the colouring-matter obtained by acting with naphthicetol upon the
diazo-compounds of Betanaphthylamine-alpha-sulphonic acid has also a claret shade
but is distinguished by the ease, with which its sodium and potassium salts may be
prepared in a crystalline condition.
Dotad this 19th dox of Santamber 1900
ABEL & IMRAY,
Agents for the Applicant.
Manufacture of Derivatives of Para-Amido-Alpha-Naphthol and of
Colouring-Matters derived from them.
I, OTTO NICHOLAS WITT, of Lindenallée 33, Westend, Bei Berlin, Germany, Doctor
of Philosophy, 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:-
In para-amido-alpha-naphthol the hydrogen of both the ainido and the hydroxyl-
groups is susceptible of being replaced by acid radicles, but no means hive as yet
been known of limiting the reaction to only one of these groups.
Grandmougin and Michel, who have studied the reaction of acetic anhydride on
para-ainido-alpha-naphthol (Berichte d. d. Chem. Gesellschaft, XXV. p, 978) distinctly
state, that di-acetyl-para-amido-naphthol is the only product formed in this reaction,
a well crystallised compound melting at 158° C.
.
I have discovered, that, contrary to these observations, the amido group only may
be acetylised under certain conditions which I have ascertained. The substance so
obtained and which has its hydroxyl-group intact, shows great similarity of behaviour
to the phenols in general and the naphthols in particular. I therefore propose to call
this substance naphthacetol, indicating thus its relation to the naphth ols.
Naphthacetol is formed, if para-ainido-alpha-naphthol hydrochloride be reacted
upon, in the presence of dry sodium acetate with no more than one molecule of acetic
anhydride, diluted by some suitable solvent, or if the above mentioned di-acetyl-para-
amido-naphthol of the melting point 158° C. be heated with caustic alkali until
complete solution takes place.
In the first of these processes of formation the amido group only is attacked, while
the hydroxyl group is not acted upon, in the second the acetyl group is removed from
the hydroxyl group only, while it remains intact in the amido group. On both these
reactions a process for the manufacture of naphthacetol may be based.
To obtain naphthacetol by the first method. I proceed as follows:-
I mix 10 parts by weight of dry para-amido-alpha-naphthol with 5 parts of dry
sodium acetate in a suitable vessel of enamelled cast-iron or porcelain, taking care
that both these ingredients are in a finely-powdered condition.
To this mixture I add 5 parts, by weight, of acetic anhydride, previously diluted
with 10 parts of glacial acetic acid. On stirring the mixture, heat is generated
spontaneously and the mixture assumes the condition of a thin paste. If water be
added in this stage, the naphthacetol separates out. I prefer however to distil off the
acetic acid added as a solvent together with the acid formed in the reaction and
thus to recover it for further use. It is preferable to effect this distillation in vacuo.
The residue from it is a mixture of naphthacetol with sodium chloride and acetate,
from which the former in ly be obtained by washing with water: It may then be
recrystallised either from boiling water in which it is sparingly soluble or from spirit
in which it dissolves pleutifully on the water-bath, setting out in fine woolly needles
on cooling. Pure: naphthacetol has its melting point at 1870 C., it is easily soluble
in caustic alkalies without decomposition.

page_text: If by some mistake, too much acetic anhydride has been used in the preparation o
naphthacetol, the above mentioned di-acetate of the melting point 157° may be
formed.
In this case, as well as in any other, when it may be necessary to transform this
diacetate into naphthacetol, this may easily be effected by mixing it with so much of
a strong solution of caustic soda or potash, that a thin paste is formed.
On heating
this on the water-bath, gradual solution takes place.
As soon as all is dissolved the formation of naphthacetol is completed. It may then
be precipitated from the mixture by the addition of an acid.
Congeners of naphthacetol, which in their properties closely resemble the latter,
may easily be obtained by substituting, in the process set forth, for acetic anhydride,
the anhydrides of other organic acids. Thus by reacting upon a mixture of 3 parts
para-amido-alpha-naphthol hydrochloride with 2-3 parts of butyric anhydride the
mono-butyryl derivative of paramidonaphthol may be obtained, which has its melting
point at 160-161° C. If instead of butyric anhydride, 2.7 parts of valerianic
anhydride be used, the mono-valerianyl derivative is obtained, which melts at 204-
205° C. By using 3 parts of benzoic anhydride the mono-benzoyl derivative is
produced, melting at 228-229° C.
All these substances form colourless glistening needles if recrystallised from
alcohol.
It has already been said, that naphthacetol closely resembles the naphthols in its
chemical behaviour.
This resemblance is also shewn by the fart, that naphthacetol is easily acted upon
by diazo compounds and that true azo-colouring-matters are formed in this reaction.
This property of naphthacetol may be utilised industrially in various ways of which
the following are examples:
1. If cotton cloth or any other suitable woven material be impregnated with a
solution of naphthacetol, to which some sodium carbonate may advantageously be
added, and dried, then coloured patterns may be obtained on such materials by
printing upon them with thickened solutions of diazo compounds, in a manner exactly
similar to the process now largely in use for materials impregnated with solutions of
the two naphthols.
The shades obtained from naphthacetol by this process differ considerably from
those obtained by the same diazo-compounds from either beta or alpha naphthol, so
that by the introduction of naphthacetol the number of shades obtainable by this
direct printing process is considerably increased. Thus for instance, naphthacetol
yields, if printed upon with the diazo-derivative of
Aniline, a bright scarlet,
Pseudocumidiu, a fine rose,
Alphanaphthylamine, a purplish red,
Betanaphthylamine, a rich claret,
Benzidine, a reddish purple,.
Tolidine, a bluish purple,
Dianisidine, a blue.
Other bases may be used in like manner with corresponding effects.
2. Instead of forming the azo-dye on the material as above described, it may also
be prepared separately and then used for dyeing and calico-printing. Though the
azo-colours, the formation of which has been described above may be used for such
purposes, if prepared independently from the fibre, it will be generally found better
to use the diazo-compounds of sulphonated bases, which yield dye-stuffs of greater
solubility. Thus, for instance, diazobenzol-sulphonic acid, if acting upon naphthacetol,
yields a bright scarlet. With the diazo derivative of naphthionic acid a reddish
purple is obtained which is admirably suited to wool dyeing. The diazo-derivative of
Bronner's betanaphthylamine-sulphonic acid gives a dyestuff of a claret colour, whilst

page_text: the colouring-matter obtained by acting with naphthacetol upon the diazo compound
of betanaphthylamine-alpha-sulphonic acid has also a claret shade but is distinguished
by the ease with which its sodium and potassium salts may be prepared. in a
crystalline condition.
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 naphthacetol by causing one molecule of acetic anhydride
to act upon one molecule of para-ainido-alpha-naphthol or any of its salts in the
presence of an excess of sodium acetate.
2. The manufacture of naphthacetol by heating di-acetyl-para-amido-alpha-naphthol
with an aqueous solution of a caustic alkali until a clear solution is obtained and by
precipitating with acid.
3. The manufacture of colouring matters from naphthacetol by the action of
diazo-compounds upon it.
4. The preparation of congeners of naphthaceto! by substituting for the acetic
anhydride mentioned in the first claim the anhydrides of other organic acids.
Dated this 8th day of June 1897
ABEL & IMRAY,
Agents for the Applicant.