A Process for the Preparation of Orthotoluolsulpho Acid and Ortho- sulpho Benzoic Acid by Oxidation of Orthothiocresol.
Year: 1897

page_text: Date of Application, 30th Apr., 1897-Accepted, 6th Nov, 1897
A Process for the Preparation of Orthotoluolsulpho Acid and Ortho-
sulpho Benzoic Acid by Oxidation of Orthothiocresol.
I, JULIUS HAUFF, of Chemical Works, Feuerbach near Stuttgart, Germany,
Manufacturer, 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:-
The orthotoluol sulpho acid and the orthosulpho benzoic acid which are the original
products important for the preparation of the pure sulfinide of the orthobenzoic acid
have hitherto not yet been prepared in a direct manner out of suitable original
materials in a chemically pure form. According to the methods used in the technical
working for their manufacture, isomeric compounds are obtained, the separation of
which is partly incomplete, partly combined with considerable costs.
Now I have found that the chemically pure orthothiocresol easily obtainable
according to the methods of Leuckardt (Journal of Practical Chemistry 1890, 41, 186)
and Lustig (Chemical Gazette XXI. 213) is an exceedingly valuable original material
for the preparation of the chemically pure ortho toluol sulpho acid and the chemically
pure ortho sulfobenzoic acid.
By treating the said orthothiocresol with suitable oxidizing agents, best with
permanganate of potassium, firstly the sulphhydrat group is transformed into the
sulpho acid group, whereby the orthotoluolsulpho acid arises; in the further action of
the oxidizing agent the methyl group is oxydized and thus transformed into the
carboxyl group, whereby the sulpho benzoic acid is formed.
These oxidizing operations perform themselves quantitatively and can be carried
out in one or the other sense with estimated quantities.

page_text: of the orthothiocresol which are obtained according to the cited method of Leuckhardt
out of the corresponding substitution products of the orthotoluidine, the substitutives
of which are not altered by the usual oxidizing agents, therefore to the halogens-,
sulpho- and nitro-substitution products of the orthothiocresol substituted in the
benzol core whereby the corresponding products of substitution of the ortho toluol
sulpho acid and of the ortho sulfo benzoic acid are obtained.
Likewise the ortho sulpho benzoic acid is obtained, when going out of the
orthothiocresol being chloridized in the lateral chain, but only with this difference,
that less oxidizing agent is necessary.
If for instance instead of the orthothiocresol its dichloro-ortho-thiocresol double
chloridized in the lateral chain is used as the original product then by the described
way the latter can be transformed into the dichloro toluol sulpho acid. When this
acid is boiled with alcalis it changes into the benzaldehyde ortho sulpho acid, which
by oxidation is easily transformed into the ortho sulpho benzoic acid. While for the
transformation of the toluol sulpho acid into the benzoic sulpho acid three atoms of
oxygen are to be employed, the third part of it, consequently one atom of oxygen
suffices, when for this synthesis the thiocresol, which is double chloridized in the
lateral chain, is used as the original product.
When using the monochloro thiocresol a third part of the oxidizing agent is saved,
while for the transformation of the trichlorothiocresol firstly into the trichlorotoluol
sulpho acid and then into the sulpho benzoic acid no oxidation at all, but a simple
hydrolysis with alcalis is wanted.
Having now particularly described and ascertained the nature of this invention
and in what manner the same is to be performed I declare that what I
claim is
The hereindescribed process for the preparation of ortho toluol sulpho acid and
ortho sulpho benzoic acid by oxidation of orthothiocresol.
Uated Abra 27th dov ot
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LX07
Dated Ebra 2s dow at
H. GARDNER,
Patent Agent, 166 Fleet Street, London,
Agent for the said Julius Hauff.