Improvements in the-Production of Acetophenonphenetidide.
Year: 1898

page_text: Improvements in the-Production of Acetophenonphenetidide.
8.1.
I, FRIEDRICH VALENTINER, of Leipsic-Plagwitz, in the Empire of Germany,-
Chemical Manufacturer and 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 :-
My invention relates to an improved process for the production of acetophenon-
phenetidide in vacuo.
The process already known for the production of acetophenonphenetidide is based
upon the condensation of acetophenone and p-phenetidine with the aid of heat. The
temperature at which this reaction takes place is from 135 degrees to 140 degrees
Centigrade, that is at a temperature at which the p-phenetidine decomposes in the
presence of air, and consequently causes various discolorations. One of the greatest
difficulties which has to be overcome in carrying out the above mentioned process is -
to avoid these decompositions. After the product of the reaction has been cooled the
crystallization of the acetophenonphenetidide takes place from the mother liquor..
The wet crystals are then placed upon a suction apparatus in order to remove the
remaining mother liquor, and subsequently washed with alcohol for a prolonged time..
In spite of this complicated and vigorous purification it is still only possible to obtain
the acetophenonphenetidide in the state of purity by means of repeated
recrystallization from alcohol, ether, or chloroform. From the mother liquors drawn
off acetophenone, which had not taken part in the reaction can be recovered for the
most part, but the p-phenetidine on the other hand cannot be recovered.
The following description sets forth a process for the production of acetophenon-
phenetidide in vacuo which obviates any production of semi-fluid impurities, and
which produces by means of a single short operation perfectly pure acetophenon-
phenetidide, and at the same time gives back the compounds which have not entered
into the reaction in an almost chemically pure condition.
My new process is conducted as follows:-
1.2 kg. acetophenone is heated in an exhausted retort with 1.37 kg. of p-phene-
tidine until there commences a vigorous separation of water. After this the
temperature is allowed to rise gradually, and the whole contents of the retort
fractionally distilled off in vacuo. Acetophenone and p-phenetidine are collected
separately, and can be immediately used over again for a fresh charge. At the
temperature of 210 degrees to 212 Centigrade and an atmospheric pressure of 72 m.m.
the acetophenonphenetidide distils and condenses to a pale yellow oil, which on
cooling solidifies into beautiful clear crystals. A single washing with alcohol renders
the product chemically pure.
The technical advantage of this process as compared with the previous one is
obvious. The manufacture of the pure product of the condensation which previously
required about a week to prepare each charge can be effected by my new process with
the simplest apparatus in four to five hours. The product is of unimpeachable purity,
and the yield is raised from 60 per cent. to about 90 per cent., and finally the
recovered materials which have not entered into combination are practically pure.
D
077

page_text: Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed I declare that what I
claim is :-
The improved process for the production of acetophenonphenetidide characterized
by heating quantities of acetophenone and of p-phenetidine in molecular proportions
in a vacuum to the combination temperature and distilling off therefrom in vacuo
the acetophenonphenetidide produced.
Dated this 5th day of March 1898.
W. P. THOMPSON & Co.,
322, High Holborn, London, W.C., Patent Agents for the Applicant.