The Manufacture of Salicylate of Phenyldimethylpyrazolone.
Year: 1890

page_text: Date of Applicatior, 5th July, 1890
Complete Specification Left, 6th Apr., 1891-Accepted, 23rd May, 1891
PROVISIONAL SPECIFICATION.
The Manufacture of Salicylate of Phenyldimethylpyrazolone.
We, HANS LÜTTKE, Analytical Chemist, of Dresden, Ludwig Scholvien,
Doctor of Philosophy, of Grünau, near Berlin, and LUDWIG FRIEDRICH RIEDEL,
Manufacturing Chemist of 12/13 Gerichtsstrasse, Berlin, all in the Empire of
Germany, do hereby declare the nature of this invention to be as follows :-
:-
Our invention relates to the manufacture of salicylate of phenyldimethylpyra-
zolone.
The salts of phenyldimethylpyrazolone have not heretofore been much experi-
mented with for the reason generally that they can only be caused to crystallize
with difficulty and therefore they cannot easily be obtained in a pure state.
According to our invention we produce salicylate of phenyldimethylpyrazolone,
which we call "salipyrin" by heating phenylhydrazine, acetyl acetic ether and
methyl-salicylic ether in the presence of a haloid hydric acid practically under
pressure.
Where phenyldimethylpyrazolone can be ready obtained, the salicylate of
phenyldimethylpyrazolone may also be produced by melting the former by means
of heat with salicylic acid and water.
Our new product when in a pure state melts at about 91.5° C. and is soluble in
alcohol, benzol or acetone but is insoluble in water and yields salicylic acid in the
presence of a strong acid, such as sulphuric acid and phenyldimethylpyrazolone in
the presence of soda lye."
Dated the 5th dor of July 1890
G. F. REDFERN & Co.,
4, South Street, Finsbury, London, Agents for the Applicants.
COMPLETE SPECIFICATION.
The Manufacture of Salicylate of Phenyl-dimethyl-pyrazolone.
We, HANS LÜTTKE, Analytical Chemist, now of Rostock, Ludwig Scholvien,
Doctor of Philosophy, of Grünau, and LUDWIG FRIEDRICH RIEDEL, Manu-
facturing Chemist, of 12/13 Gerichtsstrasse, Berlin, all in the German Empire,
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:
Our invention relates to the manufacture of salicylate of phenyl-dimethyl-
pyrazolone.
The salts of phenyl-dimethyl-pyrazolone have not heretofore been much experi-
mented with, for the reason, that most of them can only be caused to crystallize
with difficulty, and that therefore they cannot be easily obtained in a pure state.
We have found, that an easily crystallizable compound, namely the salicylate of
phenyl-dimethyl-pyrazolone, can be produced in the following manner:
We take 100 parts by weight of phenylhydrazin.
125
150
20
دو
دو
"
"
of aceto acetic ether.
of methyl-salicylic ether.
of 50 per cent. hydriodic acid and

page_text: to a pressure of about 9 to 15 atmospheres) for about ten to 12 hours. The resulting
thick brownish mass is then washed with petroleum-benzine, in order to remove the
excess of methyl-salicylic ether. The methyl alcohol is then distilled off, and the
remaining mass is left to crystallize. The deposited crystalline mass of brownish
colour is freed from the adhering liquid particles as far as possible, by suction,
and purified by re-crystallization from alcoholic solution. The body thus formed
crystallizes in the form of hexagonal tablets, and, according to elementary or
ultimate analysis, its composition may be expressed by the formula C₁₂H₁₂O₁;
It is easily soluble in alcohol, benzene (also called benzol), and acetone, less so in
ether, and very sparingly soluble in water. The melting point is at or about
91.5° C. As a proof, that a combination has been produced between the phenyl-
dimethylpyrazolone formed during the process, on the one hand, and salicylic acid
on the other hand, we will mention, that when heated with sulphuric acid, the new
.body yields salicylic acid, or when heated with soda-lye, it yields phenyldimethyl-
pyrazolone having a melting point of about 113° C.
4 grammes of the new compound produced as described, on treatment with
sulphuric acid, have yielded 1.68 grammes of salicylic acid corresponding to 42 per
cent. theoretically this quantity should be 42-3 per cent.; on the other hand, 4'0
grammes of the compound, when treated with soda-lye, have yielded 2.28 grammes
of phenyldimethylpyrazolone, or 57 per cent., which quantity according to theory
should be 57.7 per cent.
The chemical reactions underlying our process are as follows:-Phenylhydrazin
(CH-NH-NH2) and aceto-acetic ether (CH,CO-CH-COOC,H) combine
already at ordinary temperatures, thereby giving up water and forming the
compound.
CH,NH-N=C (CH,)-CH,-COOC,H,, which is subsequently converted
into phenyl-methyl-pyrazolone CH,N,O, while giving off alcohol. On the
other hand, the methyl-salicylic ether reacts with the free hydriodic acid in the
digester, so as to form salicylic acid and methyl iodide, somewhat corresponding to
the ca
we have obtained 2.85 kilogrammes of salicylate of phenyl-dimethyl-pyrazolone, or
95 per cent. of the theoretical quantity.
We would observe, that although the above proportions have been found
to give satisfactory results, they may be varied without departing from our invention, 5
as also may the duration of the heating and the temperature. Further, the
hydriodic acid, which we have found especially suitable for the purpose, may be
replaced by other halogen hydracids, such as hydrobromic acid.

page_text: Where ready made phenyl-dimethyl-pyrazolone is at disposal, the salicylate
of phenyl-dimethyl-pyrazolone may be produced by bringing the former into
contact with salicylic acid (in molecular proportions) and with water, and
applying heat until the said bodies melt together.
The salicylate of phenyl-dimethyl-pyrazolone, which is a new product, now
known as 66
salipyrin," possesses considerable antiseptic and preservative qualities ;
and is therefore especially applicable for industrial purposes and as a preservative.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed we declare that what we
claim is:
66
1. The manufacture of salicylate of phenyl-dimethyl-pyrazolone, also called
Salipyrin," by heating phenyl-hydrazin, aceto-acetic ether and methyl-salicylic
ether, in the presence of a halogen hydracid and at a suitable pressure, substantially
as described.
2. As a new article of manufacture, salicylate of phenyl-dimethyl-pyrazolone, also
called salipyrin, which in a pure state melts at about 91.5° C. and is soluble in
alcohol, benzene (benzol) or acetone, but insoluble in water, the said product
yielding salicylic acid in the presence of a strong acid, such as sulphuric acid, and
phenyl-dimethyl-pyrazolone in the presence of soda-lye.
Dated this 3rd day of April 1891.
FAIRFAX & WETTER,
433, Strand, London, Agents for the Applicants.