Improvements in the Manufacture of Saccharine, or Compounds thereof, and in the Production and Treatment of Materials for Use therein.
Year: 1895

page_text: :
4
Date of Application; June,
•
Complete Specification Left, 9th Oct., 1895-Accepted, 9th Nov., 1895
:
I
Date of Application; 1st June, 1895
Complete Specification Left, 9th Oct., 1895-Accepted, 9th Nov., 1895
PROVISIONAL SPECIFICATION...
Improvements in the Manufacture of Saccharine, or Compounds
thereof, and in the Production and Treatment of Materials for
Use therein.
I, CONSTANTIN FAHLBERG, Doctor of Philosophy, of Salbke-Westerhüsen near
Magdeburg in the Kingdom of Prussia, German Empire, Manufacturing Chemist,
do hereby declare the nature of said invention to be as follows
:-
Up to the present time there have been known two distinctly different methods
for manufacturing saccharine, namely those described in the English Patent-
Specification No. 6626 A.D. 1885 under the heads therein of "first method". and
"second method." Of those two methods the first proceeds from a mixture
composed of ortho- and para-toluenesulfamides which is obtained by means of dry
ammonia-gas or ammonium carbonate from the liquid toluene-sulfochloride; finally
the mixture of benzoic sulfinide and para-sulfaminebenzoic acid obtained is treated
as described in British Specification No. 22787 A.D. 1891, in order to separate the
para-sulfaminebenzoic acid from the benzoic sulfinide or saccharine.
According to the second or modified method the two isomeric sulfobenzoic acids
or their salts are converted by means of phosphorous-trichloride, chlorine and
ammonia into the ammonium-salt of saccharine and the diamide of para-sulfo-
benzoic acid. The latter, being almost insoluble in an aqueous solution, can be
filtered off, whereas from the ammonium-salt of saccharine left in solution pure
saccharine may be obtained without further purification.
In the course of years several economical disadvantages have been met with in
the use of said known methods.
"
According to the English Patent No. 6626 of 1885 (first method) the greater
part of para-toluenesulfonic acid is separated from the ortho-toluenesulfonic acid by
means of their' sulfochlorides,, of which the para-toluenesulfochloride is solid; whilst
the ortho-toluenesulfochloride is liquid.
This method of separation has been known as the best up the present time
however, the large quantities of phosphorous-trichloride and chlorine used in
connection therewith, make it a very costly method, considering that only the
liquid toluenesulfochloride enters into the manufacture of saccharine, whereas the
para-toluenesulfochloride is converted back into toluene, sulfuric and hydrochloric
acids by means of superheated steam; 'moreover, it has been found that the
oxydation by means of potassium-permanganate is very destructive towards the
sulfamide-group located in the ortho-position, so that a large proportion of ortho-
sulfobenzoate is 'met with after the 'oxydation in the mother-liquors. This
ortho-sulfobenzoate is then treated according to the second method described in:
English Patent 6626 of 1885, whereby it is converted into saccharine but not
without great losses as will be seen hereafter:
"
According to the last mentioned method the two isomeric sulfobenzoic acids are
caused to form two different dichlorides of which only the ortho-compound'
yields saccharine-ammonium, whilst from the other para-sulfobenzoic-diamide is.
obtained.

page_text: With the para-sulfobenzoic acid this reaction takes place almost quantitatively
according to the following equation:
CH
+2 PCI, CH
=
+ 2 POCI, + 2 NaCl.
SO₂ONa
SO₂CI
With the ortho-compound the case is different. There we see that by treatment
with phosphorous-pentachloride two isomeric dichlorides are formed, namely: a
symmetrical dichloride according to the above given equation for the para-compound,
and an unsymmetrical dichloride by the following equation
F
CH
D.
0+2 POC, +2 NaCl.
SO ON
97
SOON
The symmetrical dichloride can be almost quantitively converted with ammonia
into saccharine-ammonium by the following equation:
COCI
1
+4N13=
SO, CI
+ 2 NHCI,
"
whereas the unsymmetrical dichloride splits up with ammonia into ortho-cyan
benzenesulfonate of ammonium, as follows:-
COL

page_text: SO,OM
'
The precipitated mixture of the acid alkaline salts of ortho- and para-sulfo-
benzoic acids is brought to complete dryness and then subjected to an esterification-
process by means of an alcohol and dry gaseous hydrochloric acid; in this process
the acid alkaline salts of the isomeric sulfobenzoic acids are transformed into the
ester-benzosulfonic acids of the general formula C.H
COOR
SO₂OH,
and which are
obtained in a solid form by evaporating off the remainder of alcohol and hydro-
chloric acid after separation from the alkaline chloride formed.
The ester-benzosulfonic acids thus obtained are- first. carefully neutralised with
an alkaline carbonate and then with the aid of phosphorous pentachloride
converted into the esterbenzosulfochlorides of the general formulă CH
-
✓ COOR
SO,CI.
The two isomeric ester-benzosulfochlorides possess different physical properties;
the ortho-compound is a liquid even at a temperature of 15° C.,, whereas the
para compound is solid and fuses at about + 55° C. They are both easily soluble
in ether and benzene; but are almost insoluble in ice-water. The liquid ortho-
esterbenzosulfochloride is capable of dissolving 25% of its own weight of the
isomeric para-esterbenzosulfochloride at ordinary temperatures.
The two esterbenzosulfochlorides are converted into the corresponding amides
by means of gaseous ammonia or dry ammonium-carbonate. According to the
nature of the particular ester and the different conditions under which the
above amidation is performed, different results will be obtained as will be presently
described.
1. At ordinary atmospheric pressure and with insufficient quantities of
ammonium-carbonate or gaseous ammonia the sulfochloride-group of each of the two
esterbenzosulfochlorides is equally amidized and thereby the esterbenzosulfochloride
✓ COOR

page_text: benzoic acid. A complete transformation of the para-sulfamine benzoic ester with,
ammonia or carbonate of ammonium is effected in the presence of water in closed.
vessels at about 120° C. Under these conditions the saccharine-ammonium is left
unaltered..
4. Should the two sulfaminebenzoic esters resulting from the treatment under 1
be boiled for a certain length of time with an aqueous solution of an alkaline
carbonate, for instance with carbonate of sodium or potassium, the result will be:
complete saponification of both the compounds resulting in para-sulfamine benzoate
from the para compound, and saccharine-sodium or potassium from the ortho
compound.
'
In order to obtain pure saccharine from the above mixture the latter is treated
according to the English Patent No. 22787 of 1891.
"' :
In the separation of the ortho-toluenesulfonate of magnesium from the para-
compound there remains a large portion of para-toluenesulfonate of magnesium
which with the aid of sulfuric acid and superheated steam is converted into acid,
sulfate of magnesium and toluene. The acid-sulfate of magnesium and toluene
are both reutilised in the preparation of fresh quantities of the isomeric toluene
sulfonates of magnesium..
The para-sulfaminebenzoic acid resulting from the purification-process according
to the English Patent No. 22787 of 1891 is transformed with the aid of sulphuric
acid and superheated steam into benzoic acid, benzaldehyde and acid sulfate of
ammonium.
5 1
::
A small quantity of the meta-compound resulting from the treatment of toluene
with sulfuric acid associates the other isomeres, the para- and ortho-compounds,
throughout all the operations; it behaves like the para-compound in all the
reactions and is finally separated as meta-sulfamine benzoic acid along with..the
para-sulfaminebenzoic acid in the purification of the crude saccharine according to
the British Patent No. 22787 of 1891.
Having thus exhibited the nature of my improvements to the manufacture of
saccharine I now proceed to describe the series of steps or operations composing the
improved manufacturing process as a whole.
Operation I.-Three parts of toluene are carefully treated with eight parts of
common hydrated sulfuric acid of 66° Bé. according to the English Patent
No. 6626 of 1885 (first method) and converted thereby i in a mixture of the
isomeric ortho- and para-toluenesulfonic acids. (A small quantity of meta-compound
is also formed in this reaction alongside with the others, but the meta-compound
can be neglected in the following on account of its similar behaviour with the
paratoluenesulfonic acid.).
1'
Operation II. The above mixture of toluenesulfonic acids is first treated to the
extent of the excess of sulfuric acid with chalk and then the remaining toluene-
sulfonic acids are neutralized with caustic-magnesia or carbonate of magnesium, or
the whole mixture is first completely neutralised with chalk, so as to form toluene-
sulfonates of calcium and then the latter are transformed with sulfate of magnesium
into sulfate of calcium and toluenesulfonates of magnesium (part of the sulfate of
magnesium used being that which is obtained from the regeneration of toluene, as
described under Opération XI).
Operation I-The sultate of lime formed in the preceding operation is filtered
off and the aqueous solution of toluene sulfonates of magnesium concentrated to a
sufficient degree of concentration to allow para-toluenesulfonate of magnesium to
crystallise, the ortho-toluenesulfonate of magnesium remaining in solution together
with a certain amount of para-toluenesulfonate of magnesium.
Operation IV. The last named solution is converted by means of carbonates of
potassium or sodium into the corresponding alkaline toluenesulfonates whereby
carbonate of magnesium is formed which may be advantageously utilised in
Operation II. The filtered off solution of the alkaline toluenesulfonates is then
oxydized by permanganate of sodium or potassium or any other known oxydizing;
agent into the corresponding neutral ortho- and para-sulfobenzoates.
L
:

page_text: Operation V.The alkaline liquor resulting from the preceding oxydation is then
evaporated to the concentration of a cold saturated solution of the salts contained
therein when the latter are precipitated therefrom with the aid of hydrochloric, or
any other suitable acid into the form of acid alkaline ortho- and para-sulfo
benzoates.
$ 1
Operation VI: The above precipitate is filtered off, dryed and with the aid of
an absolute alcohol and a current of gaseous hydrochloric acid converted into the
ester-benzcsulfonic acids. The alkaline-hlorides fornied, which remain undissolved
in the alcoholic solution, are filtered off, and the solution is evaporated almost to
dryness. The residue left in the still consists of almost pure, para
and ortho
esterbenzosulfonic acids.
Operation VII. The contents of the still is liquified with water and carefully
neutralised in the cold with alkaline carbonate, preferably carbonate of sodium, an
then evaporated' to dryness..
The ester-benzosulfonates thus obtained are easily soluble in common alcohol as
well as wood-spirits and can lie crystallised out of them in well shaped forms. The
sodium-salt of the ethyl-ester of ortho-benzosulphonic acid fuses at about. 208° C
ithout decomposition, whereas under the same conditions the sodium-salt of the
ethyl-ester of para-benzosulfonic acid undergoes partial decomposition.
Operátion VIII-The alkaline salts of the ester-benz sulfonic acids are treated
with phosphorous pentachloride in order to convert them into the ester-benzosulf.-
chlorides; after washing the product of the reaction with ice-cold water an oily liquid
composed of the two isomeric ester-benzosulfochlorides collects on the bottom of the
vessel and can be easily drawn off from the water by means of decantation..
Operation X-The, washed ester-benzosulfochlorides are transformed by
gaseous ammonia or carbonate of ammonium. into the amides and these are
completely saponified with an alkaline carbonate whereby, alkaline, para-sulfamine
benzoates and an alkaline salt of saccharine are obtained.
Operation X. After expelling the last traces of carbonate of ammonium and
ammonia the concentrated solution is first treated with a small quantity of
a permanganate in order to brighter its color, and, after filtering off from the
manganese-mud, treated according to English Patent No. 22787 of 1891 so as to
separate the para-sulfaminebenzoic acid froni the saccharine.
Operation XI. The para-toluenesulfonate of magnesium obtained as a by-product
in Operation is with the aid of sulfuric acid and Superheated steam converted
into toluene and acid sulfate of magnesium. The sulfate of magnesium is used in
the decomposition of calcium-toluenesulfonates into magnesium-toluenesulfonates
as described under Operation II and the regenerated toluene is reused, in
Operation I."
Operation XII. The para-sulfaminebenzoic acid obtained together with a small
quantity of meta-sulfamine benzoic acid in Operation X, is subjected to the action of
sulfuric acid and superheated steam, whereby, benzoic acid and benzaldehyde are
produced.
Dated this 1st June 1895
COMPLETE SPECIFICATION.
E
Improvements in the Manufacture of Saccharine, or Compounds
thereof, and in the Production and Treatment of Materials for
Use therein.
1. CONSTANTIN: FAHLBERG, Doctor of Philosophy, of Salbke, Westerhüšcu,
Dear Magdeburg, in the Kingdom of Prussia, German Empire, Manufacturing
Chemist, do hereby declare the, nature, ofthis invention, and in what manner

page_text: the same is to be performed to be particularly described, and ascertained, in, and
by, the following statement :-
Up to the present time there have been known only the methods-for-manu-
facturing saccharine and benzoic sulphinide described in the Specification of Letters
Patent No. 6626 A.D. 1885, under the heads therein of first method" and
"second method." Of those two methods, the first deals with the preparation of
saccharine from a mixture composed of ortho- and para-toluene sulphonamides
obtained by the action of dry ammonia gas, or of ammonium carbonate, upon
liquid toluene sulphocbloride. In this way is obtained a mixture of benzoic
sulphinide and para-sulphamine benzoic acid which can be treated as described in
the Specification of Letters Patent No. 22787 A.D. 1891, in order to separate the
para-sulphamine benzoic acid from the benzoic sulphinide.
According to the second method the two isomeric sulphobenzoic acids, or their
salts, are converted, by means of phosphorus-trichloride, chlorine, and ammonia
into a mixture of the ammonium-salt of benzoic sulphinide, and the diamido of
para-sulphobenzoic acid. The latter being almost insoluble in water can be filtered
off and, from the ammonium-salt left in solution, pure benzoic sulphinide may be
obtained without further purification.
In the course of years several disadvantages as regard economy of working have
been met with in the use of the aforesaid methods.
According to the first method of Letters Patent No. 6626 of 1885, the greater
part of the para-toluene sulphonic acid is separated from the ortho-toluenesulphonic
acid when in the form of the corresponding sulphochlorides. The para-toluene-
sulphochloride is solid whilst the ortho-toluenesulphochloride is liquid. A portion
of the para-toluenesulphochloride, however, remains dissolved in the ortho-tolueue-
sulphochloride and appears in the finished product as para-sulphamine-benzoic acid
and has to be removed (as described in the Specification of Letters Patent 22787
of 1891) in order to obtain pure benzoic sulphinide..
This method of preparation, as described in the Specification of Letters
Patent 6626 of 1885 has been known as the best up to the present time, but the
large quantities of phosphorus tri-chloride and chlorine used in connection there-
with make it a costly method, considering that only the liquid toluenesulphochloride
gives benzoic sulphinide, the solid para-toluene sulphochloride being converted
back into toluene, sulphurous, sulphuric, and hydrochloric, acids by means of super-
heated steam. Moreover it has been found that the oxydation by means of
potassium-permanganate is destructive towards the sulphamide group, when situated
in the ortho-position, so that a large proportion of ortho-sulphobenzoate is met
with in the mother liquors after the oxydation. This ortho-sulphobenzoate may
then be treated according to the second method described in Letters Patent 6626
of 1885 whereby it is converted into benzoic sulphinide but not without great losses
as will be seen bereafter.
According to the last mentioned method the two isomeric sulphobenzoic acids
are caused to form two different dichlorides, of which only the ortho-compound
yields the ammonium salt of benzoic sulphinide whilst from the other para-sulpho-
benzoic-diamide is obtained:
With the para-sulphobenzoic acid this reaction takes place almost quantitatively
according to the following equation
/COONa
COCI
CH
+ 2 PC₁₂ = C¸H
+2 POCI, + 2 NaCl.
SO,ONa
SO.CI
With the ortho compound the case is different, because, by treatment with
phosphorous-penta-chloride, two isomerie dichlorides are formed from it, namely; 50
a symmetrical di-chloride according to the equation given above for the

page_text: para compound, and an unsymmetrical dichloride according to the following
equation:
COON
ZOCLX
SO,ONa
SO,/
7:1
The symmetrical dichloride can be almost quantitively converted by ammonia
into the ammonium salt of benzoic sulphinide according to the following.
equation
CH
+4NH = CH
NNH + 2 NH⭑CI,
B
SO CL
:
In connection with the above described reactions, therefore, there are always
series losses of material which make the processes costly.
It is the object of the present invention to so improve the production of benzoic
sulphinide that the disadvantages mentioned are overcome. The insprovements by
which this result is obtained are as follows :-
The isomeric toluenesulphonic acids are not separated as toluenesulphochlorides
but as magnesium-toluene-sulphonates of which the magnesium para-toluene-
sulphonate is far more difficultly soluble in water than is the corresponding
magnesium ortho-toluenesulphonate.
Moreover the oxydation is not applied to the toluenesulphamides, but to the
toluenesulphonates whereby I am enabled to confine the oxydation to the methyl
group so that waste of oxydizing agent, and destruction of the sulphamide-group
are prevented: In this way, I obtain from the oxydation an aqueous solution of
the two isomeric alkaline sulphobenzoates which is concentrated and from.

page_text: which, by means of hydrochloric acid a mixture of the acid alkali salts of
соон
ortho- and para-sulphobenzoic acids of the general formula C.H. SO₂OM
precipitated.
are
The precipitated mixture of the acid alkali salts of ortho- and para-sulphobenzoic
acids is completely dried, and then, subjected to an esterification process, by means
of an alcohol and dry gaseous hydrochloric acid. In this process the acid alkali
salts of the isomeric sulphobenzoic acids are transformed into the ester-benzo-
✰ T
✓
sulphonic acids of the general formula CH COOR which are obtained in a solid
SO₂OH
form by evaporating off the remainder of alcohol and hydrochloric acid after
separation from the alkaline chloride formed.
The ester-benzosulphonic acids thus obtained, are first carefully neutralised with
an alkaline carbonate and then with the aid of phosphorus pentachloride converted
into the esterbenzosulphochlorides of the general formula CH
COOR
SO₂CI,
assuming
ethylic alcohol be employed; which alcohol I prefer. The two isomeric ester-
benzosulphochlorides possess different physical properties, the ortho-compound is a
liquid even at a temperature of -15° C., whereas the para compound is solid and
fuses at about + 55° C. They are both easily soluble in ether, and benzene, but
are almost insoluble in ice cold water. The liquid ortho-esterbenzosulphochloride
is capable of dissolving, and retaining in solution, at ordinary temperatures,
25% of its own weight of the isomeric para-esterbenzosulphochloride.
The two esterbenzosulphochlorides (i.e. the liquid body together with the dissolved
para body) are converted into the corresponding amides by means of gaseous
ammonia or dry ammonium-carbonate. According to the nature of the particular
ester and the different conditions under which the above amidation is performed,
different results will be obtained as follows:
(1.) At ordinary atmospheric pressure, and with quantities of ammonium-
carbonate, or gaseous ammonia, insufficient to produce the reaction mentioned
in (2) the sulpho-chloro group of each of the two ester-benzosulphochlorides is
equally amidized and thereby the esterbenzosulphochloride converted into sulph-
aminebenzoic ester of the general formula C.H.
COOR
SO,NH,.

page_text: acid. A complete transformation of the para-sulphaminebenzoic ester with ammonia,
or carbonate of ammonium, is effected in the presence of water, in closed vessels,
at about 120° C. Under these conditions the ammonium salt of benzoic sulphinide
is left unaltered.
(4.) Should the two sulphamine benzoic esters resulting from the treatment
under (1) be boiled with an aqueous solution of an alkaline carbonate (for instance
with carbonate of sodium, or potassium,) the result will be complete saponification
of both the compounds; resulting in para-sulphamine benzoate from the para
compound and the sodium, or potassium, salt of benzoic sulphinide from the ortho
compound.
In order to obtain pure benzoic sulphinide from the above mixture, the latter
may be treated according to Letters Patent No. 22787 of 1891.
In the separation of the ortho-toluene-sulphonate of magnesium from the para-
compound there remains a large portion of para-toluenesulphonate of magnesium
which, with the aid of sulphuric acid and superheated steam, is converted into acid
sulphate of magnesium and toluene. The acid sulphate of magnesium and toluene.
are both re-utilised in the preparation of fresh quantities of the isomeric toluene
sulphonates of magnesium.
The para-sulphamine benzoic acid resulting from the purification process,
according to Letters Patent No. 22787 of 1891, may be transformed, by means of
sulphuric acid and superheated steam, into benzoic acid, benzaldehyde, and acid
sulphate of ammonium.
A small quantity of the meta compound resulting from the treatment of toluene
with sulphuric acid associates with the other isomers, the para and ortho compounds,
throughout all the operations; it behaves like the para compound in all the
reactions, and is, finally, separated as meta-sulphamine benzoic acid along with the
para-sulphaminebenzoic acid in the purification according to Letters Patent
No. 22787 of 1891.
'
Having thus exhibited the nature of my improvements in the manufacture of
saccharine I now proceed to describe the series of steps, or operations, composing
the improved manufacturing process as a whole. The parts are by weight.
Operation J.-Three parts of toluene are carefully treated with eight parts of
common hydrated, or ordinary, sulphuric acid of 66° Bé. according to Letters
Patent No. 6626 of 1885 (first method) and converted, thereby, into a mixture of
the isomeric ortho- and para-toluenesulphonic acids. A small quantity of meta
compound is also formed with the others in this reaction, but its presence can be
disregarded in the following description on account of its behaviour being similar
to that of the paratoluenesulphonic acid.
Operation II. The above mixture of toluenesulphonic acids is first treated (to
the extent of the excess of sulphuric acid) with chalk, (calcium carbonate,) and
then the remaining toluene sulphonic acids are neutralised with caustic magnesia,
or carbonate of magnesium, or the whole mixture is first completely neutralised
with chalk, (calcium carbonate), so as to form toluenesulphonates of calcium, and
then the latter are transformed, with sulphate of magnesium, into sulphate of
calcium and toluenesulphonates of magnesium. Part of the sulphate of
magnesium, used in this operation, may be that which is obtained from the
regeneration of toluene as described under Operation XI.
Operation III.-The sulphate of lime, formed in the preceding operation, is
filtered off, and the aqueous solution of toluene sulphonates of magnesium concen-
trated to a sufficient degree of concentration to allow the para-toluene-sulphonate of
magnesium to crystallize, the ortho-toluene-sulphonate of magnesium, remaining
in solution, together with a certain amount of para-toluene-sulphonate of
magnesium.
Operation IV. The last named solution is converted, by means of carbonate of
potassium, or of sodium, into the corresponding alkaline toluene-sulphonates,
whereby carbonate of magnesium is formed which may be advantageously utilised
in Operation II. The filtered off solution of the alkaline toluene sulphonates is
B

page_text: then oxydised by permanganate of sodium, or of potassium, or any other suitable
oxydising agent, into the corresponding ortho- and para-sulphobenzoates.
Operation V. The alkaline liquor, resulting from the preceding oxydation,
(which contains some caustic alkali and alkali carbonate), is then evaporated to the
concentration of a cold saturated solution of the salts contained therein, when the
Jatter are precipitated therefrom by means of hydrochloric acid, or any other
suitable acid, in the form of acid alkaline ortho- and para-sulphobenzoates.
Operation VI. The above precipitate is filtered off, dried, and, with the aid of
almost absolute alcohol, and a current of gaseous hydrochloric acid, converted into
the ester-benzosulphonic acids. The alkaline chlorides formed, which remain
undissolved in the alcoholic solution, are filtered off, and the solution is evaporated
almost to dryness. The residue left in the still consists of almost pure. para- and
ortho-ester benzosulphonic acids.
Operation VII.-The contents of the still are dissolved in water and carefully
neutralised in.the cold with alkaline carbonate, preferably carbonate of sodium,
and then evaporated to dryness.
The ester-benzosulphonates thus obtained are easily soluble. in common alcohol,
(especially the ortho-compound), as well as wood-spirits, and can be crystallized
out of them in. well shaped. crystals. The sodium salt. of ethyl-ester of ortho-
benzosulphonic acid. fuses at about 208° C. without decomposition, whereas the
sodium salt of the ethyl-ester of para-benzosulphonic acid undergoes. partial
decomposition under those conditions.
Operation VIII.-The alkaline salts of the ester-benzosulphonic acids are
completely dried, and treated with phosphorous pentachloride, or with. phosphorous
trichloride and chlorine, or with phosphorous oxychloride, in order to convert them
into the ester-benzosulphochlorides. After washing the product of the re-action
with ice-cold water, an oily liquid, composed of the two isomeric ester-bcnzosulpho-
chlorides, collects on the bottom of the vessel, and can be easily, separated from
the water by decantation.
Operation 1X-The washed ester-benzosulphochlorides are transformed, by
gaseous ammonia, or carbonate of ammonium, into the amides, and these are
completely saponified with an alkaline carbonate, whereby alkaline para-sulphamine
benzoates, and an alkaline salt of benzoic sulphinide, are obtained.
Operation X-After expelling the last traces of ammonium carbonate and
ammonia, the concentrated solution is first treated with a small. quantity of a
permanganate in order to brighten its, colour, and, after filtering off from the
manganese mud, is treated, according to Letters Patent No. 22787 of 1891, so as to
separate the para-sulphaminebenzoic acid.
Operation XI. The para-toluene-sulphonate of magnesium, obtained.as.a bye-
product in Operation III, is, with the aid of sulphuric acid and superheated steam,
converted into toluene and acid sulphate of magnesium. The sulphate of magnesium
is used in the decomposition of calcium toluene-sulphonates into. magnesium.toluene-
sulphonates as described under Operation II, and the regenerated toluene is re-used
in Operation I..
Operation XII.--The para-sulphaminebenzoic acid obtained, together with a
small quantity of meta-sulphamine benzoic acid,,in. Operation. X, is subjected to the
action of sulphuric acid and superheated steam, whereby benzoic acid and
benzaldehyde are produced.
Having now particularly described, and ascertained, the nature of my inven-
tion, and in what manner the same is to be performed, I declare that what I
claim is:-
1. In the manufacture, or preparation, of saccharine, or benzoic-sulphinide, or
compounds, or mixtures, containing the same, the use of magnesia, or suitable salts
of magnesium, for the purpose of separating the ortho compounds from the bulk of
the para-componnd by the formation of magnesium salts of those bodies.
2. In the manufacture, or preparation, of saccharine, or benzoic sulphinide, or

page_text: compounds, or mixtures, containing the same, the separation of ortho-toluene-
sulphonic acid, from a mixture of ortho-toluene sulphonic acid and para-toluene.
sulphonic acid, (or the salts of these acids), by magnesia, or suitable salts of
magnesium, whereby the corresponding sulphonates are formed, and the bulk of the
less soluble para-toluene sulphonate of magnesium can be separated from the
mixture by crystallization.
3. In the manufacture or preparation of saccharine, or benzoic sulphinide, or
compounds, or mixtures, containing the same, the formation of the corresponding
acid salts of ortho- and para-sulphobenzoic acids of the general formula :-
from ortho- and para-toluene-sulphonates, by oxidation, and subsequent use of a
strong acid, such as hydrochloric acid, substantially as herein described.
4. In the manufacture, or preparation, of saccharine, or benzoic-sulphinide, or
mixtures, or compounds, containing the same, the esterification of the acid alkali
salts of ortho- and para-sulphobenzoic acids, by means of alcohol and hydrochloric
acid gas, to form ortho- and para-esters, substantially as described.
5. In the manufacture, or preparation, of saccharine, or benzoic-sulphinide, or
compounds, or mixtures, containing the same, the chlorination of the ester acids, or
their salts, by means of phosphorous-pentachloride, phosphorous-trichloride, and
chlorine, or phosphorous-oxychloride, to form ester sulphochlorides of the general
formula :-
into the corresponding amides, by ammonia gas, or a salt of ammonium.
7. In the manufacture, or preparation, of saccharine, or benzoic sulphinide, or
mixtures, or compounds, containing the same, the regeneration of toluene from its
salts by means of sulphuric acid and superheated steam.
8. In the manufacture, or preparation, of saccharine, or beuzoic-sulphiuide, or
mixtures, or compounds, containing the same, the production of benzoic acid and
benzaldehyde from the ester of para-sulphamine benzoic acid and from the para-
5 means of sulphuric acid and superheated steam.
9. The manufacture, or preparation, of saccharine, or benzoic-sulphinide, or
mixtures, or compounds, containing the same, by the series of operations conducted
substantially as hereinbefore explained.
10. The cycle, substantially as hereinabove described, in the manufacture, or

page_text: preparation, of saccharine, or benzoic-sulphinide, or mixtures, or compounds,
containing, the same by which magnesia, or magnesium salts, are used over and
over again, as herein set forth.
Dated the 9th day of October 1895.
JOHNSONS & WILLCOX,
47 Lincoln's Inn Fields, London, W.C., Agents.