Manufacture of Benzaldehyde, o-nitro-benzaldehyde and p-nitro- benzaldehyde.
Year: 1897

page_text: Date of Application, 20th Dec., 1897
Complete Specification Left, 14th Sept., 1898-Accepted, 12th Nov., 1898
PROVISIONAL SPECIFICATION.
Manufacture of Benzaldehyde, o-nitro-benzaldehyde and p-nitro-
benzaldehyde.
I, OLIVER IMRAY, of Birkbeck Bank Chambers, Southampton Buildings, Chancery
Lane, in the County of London, Chartered Patent Agent, do hereby declare the
nature of this invention (which has been communicated to me from abroad by The
Farbwerke vormals Meister Lucius and Brüning of Hoechst a/Main, in the German
Empire, Chemical Manufacturers) to be as follows:-
In the English Letters Patent of May 18. 1896 No. 10689, was described a new
method for the manufacture of aromatic aldehydes which consists in subjecting
benzylaniline or its homologues or substitution products (nitro- and sulphonic acid
derivatives etc.) to oxidation, whereby the corresponding benzylidene bases are
formed from the said benzyl-bases by the splitting off of 2 hydrogen atoms
according to the following simple equation:
CHNH.CH, CH + 0 = H,O + CH.N:CH.CH
6
Benzylaniline
Benzylidene-aniline
CH_N:CH.CH + HgO = CHNH, + HOC.CH.
Aniline
Benzalde-
1) NO₂.CH.CH₂ - NH.C,H.SOH + O
nitro-benzyl-
toluidine-sulphonic
acid
=
H₂O + NO₂.CH.CH: NC,H.SO₂H
nitrobenzylidene-
toluidine sulphonic acid.
=
2) NO, CH.CH: N.C,H.SO₂H + H₂O NO.CH.COH + H₂N.CH.DU₂H
nitrobenzaldehyde toluidine
sulphonic acid
Two ways are practically employed to isolate the aldehyde thus obtained: either
by extraction with solvents, which cannot be mixed with water or else by distillation
of the product of the reaction with steam, whereby most of the aldehydes
(particularly benzaldehyde and o- nitrobenzaldehyde) pass over into the distillate.
Both methods, however, meet with not inconsiderable difficulties in being carried
out on a large scale. The first method (extraction), difficult to carry out in itself,
becomes all the more so, ou account of the great inflammability of the extracting
agents employed in this case. The second method (distillation with steam), on the

page_text: other hand, yields aldehydes in a very pure state, but they separate (particularly
o-nitro-aldehydes) only partly from the distillate, whilst considerable quantities
which remain dissolved can hardly be obtained without extraction)
My correspondents have discovered a method which permits of the separation
of aldehydes from their insoluble benzylidene compounds in a handy and convenient
manner, if one of the above-mentioned sulphonic acids of benzylaniline or its homo-
logues or substitution products be. chosen as primary material. The benzylidene
sulphonic acids obtained therefrom by oxidation undergo, as has been found, by
the action of aniline (toluidine, xylidine, naphthylamine) a transformation which
results on the one .hand in aniline-sulphonic acid (toluidine-, xylidine-,
naphthylamine sulphonic acid), and on the other hand, in the aniline compound of
benzaldehyde, that is to say, benzylidene-aniline (or the toluidine-, xylidine-,
or naphthylamine compound of the aldehyde). The latter compounds of the
aldehydes which withdraw so to say the aldehydes in concentrated form from the
strongly diluted product of reaction, are then decomposed in the usual manner
with diluted mineral acids into the auilino base and the aldehyde.
The following equations may illustrate the process of the chemical reaction-
1.) NO.CH.CH2.NH.CH.SOH + O
nitrobenzylaniline sulphonic acid
=
H₂O + NO̟CH.CH: N.CH.SOH,
nitrobenzylidene-aniline sulphonic
acid
nitrobenzaldehyde aniline.
The practical carrying out of the method may be illustrated by the following
example:-
A solution of 164 kilos. of sodium o- or p-nitrobenzylidene-aniline sulphonate;
obtained by oxidation of o- or p-nitro-benzylsulphonic acid as described in Letters
Patent of May 18, 1896 No. 10689, is treated with a solution of 72 kilos. of p-tolui-
dine hydrochloride (or with the equivalent quantity of another toluidine salt or of an
aniline, xylidine-, or naphthylamine salt.)
The nitrobenzylidene-toluidine (nitro-benzylidene-aniline, xylidine, -naphthyl-
amine,) separates at once, whilst the aniline sulphonic acid remains in, solution
from which it may be recovered in the usual manner.
The nitrobenzylidene-toluidine (aniline, xylidine, naphthylamine) thus obtained,
is stirred in the cold with the calculated quantity of a diluted minéral acid, whereby
the well-known conversion into nitro-benzaldehyde and toluidine (aniline, xylidine,
naphthylamine) at once takes place. The insoluble nitrobenzaldehyde separates
and is filtered off; in the filtrate is found the whole of the p-toluidine, (aniline,
xylidine, naphthylamine) which may at once be employed for another operation.
In this example there may be substituted for the o- or p-nitrobenzylidene-aniline
sulphonic acids the equivalent quantities of o- or p-nitrobenzylidene-toluidine-
xylidine or naphthylamine sulphonic acids and thus in all cases o- or p-nitro-
benzaldehyde is obtained.
If for the said nitrobenzlidene sulphonic acids there be the equivalent quantities
of benzylidene-aniline sulphonic acids (or their homologues) benzaldehyde is
obtained.
Dated this 20th day of December 1897
ABEL & IMRAY,
Agents for the Applicant.

page_text: :
Manufacture of Benzaldehyde, o-nitrobenzaldehyde and p-nitro-
benzaldehyde.
I, OLIVER IMRAY, of Birkbeck Bank Chambers, Southampton Buildings, Chancery
Lane, in the County of London, Chartered Patent Agent, do hereby declare the
nature of this invention (which has been communicated to me from abroad by the
Farbwerke vormals Meister Lucius and Brüning of Hoechst a/Main, in the German
Empire, Chemical Manufacturers) and in what manner the same is to be performed,
to be particularly described and ascertained, in and by the following statement :-
In the Specification No. 10689 of 1896, was described a new method for
manufacturing aromatic aldehydes which consists in subjecting benzylaniline or its
homologues or substitution products, (nitro- and sulphonic acid derivatives &c.) to
oxidation whereby the corresponding benzylidine bases are formed from the said
benzyl bases by the splitting off of 2 hydrogen atoms according to the following
equation.
C H.NH.CH..CgH + O = H,O + CHN: CH.CH.
Benzylaniline
Benzylidene-aniline.
CH..NH.CH,.CH. + O = H,O + C,H,N: CH.CH.
Benzylaniline
Benzylidene-aniline.
These benzylidene-bases, as is known, take up 1 molecule of water unde
ion of diluted mineral acids and decompose into the aniline base and aro
ehyde
-
nitro-benzyl-toluidine
(1) NO,CH..CH, – NH.C,HSOH + O = HẠO + NO, CHẠCH: N.CH SO H
6'
nitrobenzylidene-toluidine
(1) NO̟CHCH₂
-
NH.CH..SO,H+ 0 = H₂O + NO.CH..CH: N.CH..SO,H
nitro-benzyl-toluidine
-sulphonic acid.
nitrobenzylidene-toluidine
sulphonic acid.
-sulphonic acid.
sulphonic acid.
(2) NO.CH.CH: N.C,H.SO,H + H2O = NO₂.CH.COH + H,N.C,H..SO₂H.
nitrobenzaldehyde toluidine sulphonic
acid.
Two ways are practically employed to isolate the aldehyde thus obtained; either
by extraction with solvents, which cannot be mixed with water or else by distillation
of the product of the reaction with steam, whereby most of the aldehydes (particu-
larly benzaldehyde and o-nitrobenzaldehyde) pass over into the distillate. Both
methods, however, meet with not inconsiderable difficulties in being carried out on
a large scale. The first method (extraction), difficult to carry out in itself, becomes
all the more so, on account of the great inflammability of the extracting agents
employed in this case. The second method (distillation with steam) on the other
hand, yields aldehydes in a very pure state, but they separate (particularly o-nitro-
aldehydes) only partly from the distillate, whilst considerable quantities which
remain dissolved can hardly be obtained without extraction.
My correspondents have discovered a method which permits of the separation of
aldehydes from their insoluble benzylidene compounds in a handy and convenient
manner, if one of the above mentioned sulphonic acids of benzylaniline or its
homologues or substitution products be chosen as primary material.
The

page_text: benzylidene-sulphonic acids obtained therefrom by oxidation undergo, as has been
found, by the action of aniline (toluidine, xylidine, naphthylamine) a transformation
which results on the one hand in aniline-sulphonic acid (toluidine, -xylidine,
-naphthylamine-sulphonic acid), and on the other hand, in the aniline compound of
benzaldehyde, that is to say, benzylidene-aniline (or the toluidine-xylidine- or
naphthylamine compound of the aldehyde). The latter compounds of the aldehydes
which withdraw so to say the aldehydes in concentrated form from the strongly
diluted product of reaction, are then decomposed in the usual manner with diluted
mineral acids into the aniline base and the aldehyde.
The following equations may illustrate the process of the chemical reaction :—
1) NO2.CH.CH.NH.CH..SO, H + 0 = H₂O+NO₂.CH.CH: N.CH.SO₂H
nitrobenzylaniline-sulphonic acid
nitrobenzylidene-aniline
sulphonic acid
2) NÓ.C.H.CH: N.CH.SO H + CH.NH, NO.CH.CH N.CH
nitrobenzylidene-aniline
aniline
The practical carrying out of the method may be illustrated by the following
example
--
A solution of 164 kilos. of sodium o- or p-nitrobenzylidene-aniline-sulphonate,
obtained by oxidation of o- or p-nitro-benzyanilinesulphonic acid as described in
the Specification No. 10689 of 1896 is treated with a solution of 72 kilos. of
p-toluidine hydrochloride (or with the equivalent quantity of another toluidine salt
or of an aniline- xylidine, or naphthylamine salt.)
The nitrobenzylidene-toluidine (nitro-benzylidene-aniline,- xylidine, -naphthyl-
amine) separates at once, whilst the aniline-sulphonic acid remains in solution from
which it may be recovered in the usual manner.
The nitrobenzylidene-toluidine (-aniline,- xylidine,- naphthylamine) thus obtained,
is stirred in the cold with the calculated quantity of a diluted mineral acid, whereby
the well known conversion into nitro-benzaldehyde and toluidine (aniline, xylidine,
naphthylamine) at once takes place. The insoluble nitrobenzaldehyde separates and
is filtered off; in the filtrate is found the whole of the p-toluidine, (aniline, xylidine,
naphthylamine) which may at once be employed for another operation.
In this example there may be substituted for the o- or p-nitrobenzylidene-
aniline-sulphonic acids the equivalent quantities of o- or p-nitrobenzylidene-
toluidine-, xylidine-, or naphthylamine-sulphonic acids and thus in all cases o- or
p-nitrobenzaldehyde is obtained.
If for the said nitrobenzylidene sulphonic acids there be substituted the equivalent
quantities of benzylidene-aniline-sulphonic acids (or their homologues) benzaldehyde
is obtained.
:
Having now particularly described and ascertained the nature of this inven-
tion and in what manner the same is to be performed, I declare that what I
claim is :-
1. The herein described manufacture of benzaldehyde, o-nitrobenzaldehyde and
p-nitrobenzaldehyde by treating the benzylideneaniline-sulphonic acids or their
homologues, or the o- or p-nitrobenzylidene-anilinesulphonic acids or their
homologues, with aniline, toluidine, xylidine or naphthylamine, or the metallic salts
of the said sulphonic acids with the salts of the said aniline bases, and by separating

page_text: in the usual manner the benzylidene, or the o- or p-nitrobenzylidene compounds,
thus obtained, by means of diluted mineral acids into aldehyde and the aniline base.
2. Benzaldehyde, ortho-nitrobenzaldehyde and para-nitrobenzaldehyde manu-
factured as above set forth.
Dated this 14th day of Contamhan 1000
ABEL & IMRAY,
Agents for the Applicant.