Improvements in the Manufacture of Dialkyl Metamidocresols.
Year: 1890

page_text: Date of Application, 11th Dec., 1890
Complete Specification Left, 10th Sept., 1891-Accepted, 24th Oct., 1891
PROVISIONAL SPECIFICATION.
[Communicated from abroad by Messrs. WIRTH & Co., of Frankfort-on-the-
Main, in the Empire of Germany, acting as agents of A. Leonhardt & Co.,
of Muhlheim, near Frankfort-on-the-Main, in the Empire of Germany,
Manufacturers.]
· Improvements in the Manufacture of Dialkyl Metamidocresols.
I, HENRY HARRIS LAKE of the firm of Haseltine, Lake & Co., Patent
Agents, 45 Southampton Buildings, in the County of Middlesex, do hereby declare:
the nature of this invention to be as follows:-
There are at present several known methods of producing dialkyl-metaamido-
phenols but the higher homologues of these substances have not hitherto been
prepared.
The communicators have discovered that there are several ways of producing
dimethyl or diethyl-metaamidocresol namely.
1. By diazotizing metaamido-dialkyltoluidine and decomposing the diazo-
derivative by means of water.
2. By sulphonating dialkyltoluidine and melting the obtained sulpho compound
with alkalies at a high temperature.
3. By alkylating metaamidocresol which itself may be produced by melting
toluidinesulphoacid with alkalies at a high temperature.
4. By heating methylresorcine with alkylamines of the fatty series at a high
temperature and under pressure.
The dialkylmetaamidocresols obtained in this way differ in several characteristics
from the corresponding dialkylmetaamidophenols.
Dated this 11th day of December 1890.
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, Agents for the Applicant.
COMPLETE SPECIFICATION.
Improvements in the Manufacture of Dialkyl Metamidocresols.
1, HENRY HARRIS LAKE, of the firm of Haseltine, Lake & Co., Patent,
Agents, 45 Southampton Buildings, in the County of Middlesex, 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 :-
There are several known methods of producing dialkylmetaamidophenols, but
the higher homologues of these snbstances and especially the dialkylmetaamido-
cresols have not hitherto been prepared.
Now, I have found that dialkylmetaamidocresols can very easily be manu-
factured and that they differ in character from their lower homologues; and
amongst the different isomeric dialkylmetaamidocresols I have found one,
dimethyl-metaamidocresol and one diethyl-metaamidocresol, to be of great value
for technical purposes.

page_text: The formula of these new products is probably the following;
43
ап
the following:
1. By diazotizing in a suitable way metaamido-dialkyl-orthotoluidines.. and
decomposing the diazo derivative by means of water.
The metaamidodialkylorthotoluidines can be obtained for instance by nitrating
the dialkylorthotoluidines in a solution of sulphuric acid and reducing the mono-
nitro compound thus formed.
2. By sulphonating dialkylorthotoluidine and melting the sulpho compound thus
obtained with alkalies at a high temperature.
The following, examples will show how this invention may be carried; into
practice.
EXAMPLE. 1. PRODUCTION OF DIMETHYLMETAAMIDOCRESOL FROM META-
AMIDODIMETHYLORTHOTOLUIDINE.
In order to obtain a good yield, 1 have found it necessary to diazotize the amido
compound in a strong acid solution and therefore I prefer to proceed as follows:
15 kilos. of metaamidodimethylorthotoluidine are dissolved in 80 litres of water
and 40 kilos. of concentrated sulphuric acid and the obtained solution after cooling
down is diazotized by means of about 7 kilos. of sodium. nitrite keeping the
temperature at about 0° C. by addition of ice. The yellowish solution of the
diazo compound is then gradually poured into hot water, and the decomposition
takes place at once with momentary development of nitrogen. After cooling
down, the liquid which now contains the sulphate of dimethyl-metaamidocresol is
neutralized by means of caustic soda lye and any resinous matters are removed by
fractionally adding a, solution of carbonate of soda. The cold liquid is then
filtered and the pure dimethyl-metaamidocresol is. precipitated by carbonate of
soda. It solidifies after standing some time and especially on addition of a little
solid piece of the same substance. When I allow the solution of diazo-dimethyl-
orthotoluidine to stand for some time at the ordinary temperature, it also
decomposes yielding dimethylmetaamidocresol; but I have found it more
expedient to proceed as shown in the above example.
The dimethylmetaamidocresol can be distilled at the ordinary atmospheric
pressure without decomposing; when crystallized out of a suitable solvent, such
as, benzol mixed with ligroine, its melting point is at 76° C. It dissolves easily, in:
mineral acids and caustic, alkalies. As to its employment for manufacturing.
coloring matters I have found that it is of great value in cases in which dimethyl
metaamidophenol is of less or no value and vice versa.
For instance, when I employ dimethyl-metaamidocresol instead of. its lower
homologue in, the, process. patented. under German Patent 47375. and Letters
Patent 8750 I get no practical result, and if I melt. phtalic anhydride with.
dimethylmetaamidocresol I get a rhodamine of less value than that patented under
Letters Patent 1537487; on the other hand, if I combine dimethylmetaamidocresol
with nitroso derivatives of aromatic amines I get blue basic dyestuffs (as is, shown
in Letters Patent 135650) which when dimethylmetaamidophenol is employed are,
only formed in comparatively small quantities.

page_text: EXAMPLE 2. PRODUCTION OF DIETHYLMETAAMIDOCRESOL FROM DIETHYL-
ORTHOTOLUIDINE.
10 kilos. of diethylorthotoluidine are dissolved in 20 kilos. of cooled fuming
sulphuric acid containing about 20% of free anhydride. To this solution about
15 kilos. of fuming sulphuric acid containing about 40% of free anhydride is
gradually added keeping the temperature at about 50° C. When a sample of the
mass is clearly soluble in dilute ammonia the whole is poured into ice water and is
transformed into the sodium salt according to well known methods.
20 kilos. of this sodium salt are then poured into 400 kilos. of molten caustic
soda at a temperature of about 250° C., the whole is well stirred, the temperature
raised to 300° C. and kept so for about half an hour. When the diethylortho-
toluidine sulpho compound is converted into diethylmetaamidocresol (which can be
ascertained by working up small samples of the melt:) the mass after cooling
down is dissolved in water and supersaturated with muriatic acid. This liquid
now contains hydrochlorate of diethylmetaamidocresol together with resinous
matters which are removed by fractionally adding a solution of carbonate of soda,
the pure diethylmetaamidocresol is then precipitated from the filtered liquid by
means of carbonate of soda or extracted with ether, benzine or the like. It
appears in the form of a thick oil which can be distilled without decomposition.
Its boiling point is 264-7° C. Its chemical properties are similar to those of the
methyl derivative. I wish it to be understood that diethylmetaamidocresol can
also be prepared by diazotizing metaamidodiethylorthotoluidine and decomposing
the diazo compound, and that dimethylmetaamidocresol can be obtained by
sulphonating dimethylorthotoluidine and melting the sulpho compound thus formed
with alkalies, substantially as shown in the examples given above.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed, as communicated to me
by my foreign correspondents, I declare that what I claim is :-
First. The production of dimethylmetaamidocresol or diethylmetaamidocresol
by the hereinbefore described processes which consist in diazotizing metaamido-
dimethylorthotoluidine or metaamidodiethylorthotoluidine and decomposing the
diazo derivative with water; or consist in sulphonating dimethylorthotoluidine or
diethylorthotoluidine and melting the obtained sulpho compound with caustic
alkalies at a high temperature, all substantially as hereinbefore described.
Second. Dimethylmetaamidocresol and diethylmetaamidocresol produced sub-
stantially as hereinbefore described.
Dated this 10th dox of Santambar 1801
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, Agents for the Applicant.