Process of Separating Orthotoluol-sulphonic and Paratoluol- sulphonic Acids.
Year: 1890

page_text: Date of Application, 6th Oct., 1890
Complete Specification Left, 20th June, 1891-Accepted, 25th July, 1891
PROVISIONAL SPECIFICATION.
New Process of Separating Orthotoluol-sulphonic and Paratoluol-
sulphonic Acids.
I. MARTIN LANGE, Ph.D., of Amersfoort, Holland, Chemist, do hereby
declare the nature of this invention to be as follows:-
A
By sulphurating toluol, orthotoluol-sulphonic and paratoluol-sulphonic acids are
obtained in varying proportions, whereas the attempts to produce the orthotoluol-
sulphonic acid alone, have hitherto not been successful, and the methods heretofore
employed for separating the said substances from each other are inconvenient.
process whereby such separation may be brought about without difficulty is,
however, of considerable importance for the preparation of saccharine or of any
particular nitro-toluol-sulphonic acid unmixed with other analogous acids.
Now I have found that the two aforesaid acids possess different degrees of
solubility in moderately diluted sulphuric acid, the paratoluol-sulphonic acid being.
soluble therein but with difficulty, while the orthotolnol-sulphonic acid is easily
soluble in the same, and this difference of solubility in the diluted sulphuric acid
affords ready means for the separation of the two sulphonic acids.
As repeated experiments have proved, diluted sulphuric acid which contains
66 per cent. of sulphuric acid corresponding to the formula SO, H₁, is the most
suitable solvent for the orthotoluol-sulphonic acid, while the paratoluol-sulphonic
acid remains undissolved therein.
The process may be carried out by digesting the salts of the mixture of the two
sulphonic acids with the diluted sulphuric acid and filtering, or separating in other
manner, after the ortho-acid has become dissolved. Or, more simply still, the
original sulphurated mass is subjected to treatment by introducing thereinto,
if considered necessary, an additional quantity of sulphuric acid, and adding water
or ice until the paratoluol-sulphonic acid has separated out.
The progress of the process is with advantage watched by means of the
microscope, water being added so long as a separation of crystals of paratoluol-
sulphonic acid still takes place.
Dated the 6th day of October 1890.
ERNEST DE PASS,
78, Fleet Street, London, Agent for the Applicant.
COMPLETE SPECIFICATION.
New Process of Separating Orthotoluol-sulphonic and Paratoluol-
sulphonic Acids.
I, MARTIN LANGE, Ph.D., of Amersfoort, Holland, Chemist, 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:-
If toluol is subjected to a process of sulphuration, orthotoluol-sulphonic and
paratoluol-sulphonic acids are obtained in varying proportions. The attempts to
produce the orthotoluol-sulphonic acid alone have hitherto not been successful, while
the methods employed at present for separating the said acids from each other are
inconvenient. A process whereby such separation may be brought about without
difficulty, is however, of considerable importance for the preparation of saccharine
or of any particular nitro-toluol-sulphonic acid unmixed with other analogous acids.
Now I have found that the two aforesaid acids possess different degrees of solubility
in moderately diluted sulphuric acid, the paratoluol-sulphonic acid being soluble

page_text: therein but with difficulty, while the orthotoluol-sulphonic acid is easily soluble in
the same, and this difference of solubility in the diluted sulphuric acid affords
ready means for the separation of the two sulphonic acids.
As repeated experiments have proved, diluted sulphuric acid which contains
66 per cent. of sulphuric acid corresponding to the formula SO, H₂, is the most
suitable solvent for the orthotoluol-sulphonic acid, while the paratoluol-sulphonic
acid remains undissolved therein.
manner,
The process may be carried out by digesting the salts of the mixture of the two
sulphonic acids with the diluted sulphuric acid and filtering, or separating in other
after the ortho-acid has become dissolved. Or, more simply still, the
original sulphurated mass is subjected to treatment by introducing thereinto,
if considered necessary, an additional quantity of sulphuric acid, and adding water
or ice until the paratoluol-sulphonic acid has separated out.
The progress of the process is with advantage watched by means of the
microscope, water being added so long as a separation of crystals of paratoluol-
sulphonic acid still takes place.
The following are two examples of the mode of proceeding:
1. One part of the mixture of the sodic salts of the two acids is digested with
4 parts of sulphuric acid having a strength of 66 per cen', either in the cold or with
application of moderate heat. After about four hours the orthotoluol-sulphonic
acid will be dissolved. The liquor is separated from the paratoluol-sulphonic acid
either by means of a suction-filter, or a centrifugal machine. From the liquor the
orthotoluol-sulphonic acid is precipitated by a calcium salt.
2. 100 parts of toluol are treated at the ordinary temperature with 600 parts of
concentrated sulphuric acid in view of sulphurating the same.
After the whole
quantity of toluol has been dissolved, 250 parts of ice or water are added, while
cold is applied from the outside, and the mass is stirred until it has become a thick
pulp. Subsequently the liquid is separated from the solid portion by means of a
suction-filter or a centrifugal machine, the paratoluol-sulphonic acid remaining
behind in the form of crystals. The two acids may thereupon be converted into
salts of calcium or sodium in known manner.
Having now particularly described and ascertained the nature of my said inven-
tion, and in what manner the same is to be performed, 1 declare that what I
claim is:
The process of separating orthotoluol-sulphonic and paratoluol-sulphonic acids,
which consist in treating the mixture of the two acids or of their salts by means of
moderately diluted sulphuric acid, or in adding water to a solution of the two acids
in concentrated sulphuric acid until the paratoluol-sulphonic acid has separated out,
and filtering, substantially as described.
DL: 001
1001
ERNEST DE PASS,
78, Fleet Street, London, and 6, Victoria Street, Nottingham,
Agent for the Applicant.