Year: 1896

page_text: Date of Application, 18th May, 1896
Complete Specification Left, 15th Feb., 1897-Accepted, 8th May, 1897
I, OLIVER IMRAY, of No. 28 Southampton Buildings, Chancery Lane, in the
County of London, Chartered Patent Agent, do hereby declare the nature of this
invention to be as follows:-
This invention is based on the observation, that the benzylcompounds of aniline
and its homologues of the general formula:
R'N CHR" + H₂O = R'NH, + R"COH.
Benzaldehyde for instance is obtained by warming benzylaniline or its homologues
with an acidulated bichromate solution, by substituting for benzylaniline, o-nitro-
benzylaniline, described by Fellmann and Stickel (Berichte der Deutschen
Chemischen Gesellschaft 19, 1605) or the p-nitrobenzylaniline of Strakosch
(Berichte der Deutschen Chemischen Gesellschaft 6, 1062) there is obtained by
the same method, in the first case o-nitrobenzaldehyde, and in the second case
p-nitrobenzaldehyde, both in condition of the greatest purity.
As an example the following process is adopted.
100 kilos. benzylaniline
500 to 1000 litres of water.
The agitator being put in action, the contents of the vessel are brought to
boil by allowing steam to pass, and by means of a suitable funnel, a solution
consisting of
50 kilos. potassium or sodium bichromate in
200 litres of water acidulated with
165 kilos. of hydrochloric acid (21 Bé.) or its equivalent of sulphuric
acid is run in, during a few hours.
Distillation of a mixture of water and benzaldehyde soon takes place. The
aldehyde is separated, if necessary, purified in the usual manner and brought into a
serviceable form.
For the benzylaniline may be substituted, in this example, the equivalent quantities

page_text: of benzyl-o-toluidine or benzyl-p-toluidine or by a mixture of the above mentioned
benzylbases.
The reaction is expressed by the following equations:-
benzylidenetoluidine
toluidine
benzaldehyde
2. MANUFACTURE OF O-NITROBENZALDEHYDE.
If in the previous example for the benzylaniline be substituted 120 kilos.
o-nitrobenzylaniline or the equivalent quantity of o-nitrobenzyltoluidine, there is
obtained, retaining the above described apparatus and process, a distillate, from
which, on cooling, the o-nitrobenzaldehyde crystallises in the known colourless
needles about a centimetre long. Distillation is continued as long as a cooled
sample of the distillate shews, on addition of acetone and soda lye, the known
indigo reaction.
If, in this example, for the o-nitrobenzylaniline be substituted p-nitrobenzylaniline
or p-nitrobenzyl-o- or p-toluidine, p-nitrobenzaldehyde is obtained.
The reactions of the second example are expressed by the following equations:-

page_text: equivalent quantity of other oxidising agents, for instance ferric salts or oxidising
manganese and lead compounds.
ABEL & IMRAY,
Agents for the Applicant.
Manufacture of Aromatic Aldehydes.
1, OLIVER IMRAY, of No. 28 Southampton Buildings, Chancery Lane, in the
County of London, Chartered Patent Agent, do hereby declare the nature of this
invention (as 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 :-
This invention is based on the observation that the benzyl compounds of aniline
and its homologues of the general formula:
R'N = CHR" + H,0 = R'NH, + R"COH.
Benzaldehyde for instance is obtained by warming benzylaniline or its homologues
with an acidulated bichromate solution; by substituting for benzylaniline, o-nitro-
benzylaniline described by Fellmann and Stickel (Berichte der Deutschen
Chemischen Gesellschaft 19, 1605) or the p-nitrobenzylaniline of Strakosch
(Berichte der Deutschen Chemischen Gesellschaft 6, 1062) there is obtained by
the same method, in the first case o-nitrobenzaldehyde, and in the second case
p-nitrobenzaldehyde, both in condition of the greatest purity.
Two methods may be employed for the practical carrying out of this invention.
Either by oxidation of the benzyl bases with acid oxidation agents in presence of
diluted mineral acids, thus obtaining at once aldehyde; or by oxidation of the
benzyl bases in a neutral solution with alkaline oxidation agents, thus obtaining
first the benzylidene compounds, which are isolated and split off by a second and
special operation with diluted mineral acids into the base and aldehyde. This
second method necessitates the application of a suitable solvent, such as acetone,
for instance, the benzyl bases being insoluble in water.
1. MANUFACTURE OF BENZALDEHYDE.

page_text: The agitator being put in action, the contents of the vessel are brought to
boil by allowing steam to pass, and by means of a suitable funnel, a solution,
consisting of
50 kilos. potassium or sodium bichromate in
200 litres of water acidulated with
165 kilos. of hydrochloric acid (21 Bé.) or its equivalent of sulphuric
acid is run in, during a few hours.
Distillation of a mixture of water and benzaldehyde soon takes place. The
aldehyde is separated, if necessary, purified in the usual manner and brought into
a serviceable form.
For the benzylaniline may be substituted, in this example, the equivalent
quantities of benzyl-o-toluidine or benzyl-p-toluidine or by a mixture of the above
mentioned benzyl bases.
The reaction is expressed by the following equations
C,H,NCHCH + H₂O
benzylidenetoluidine
toluidine
C,H,NH, + COH.CH.
ཡ་དལ།——
benzaldehyde
2. MANUFACTURE OF O-NITROBENZALDEHYDE.
If in the previous example for the benzylaniline be substituted 120 kilos.
o-nitrobenzylaniline or the equivalent quantity of o-nitrobenzyltoluidine, there is
obtained, retaining the above described apparatus and process, a distillate, from
which, on cooling, the o-nitrobenzaldehyde crystallises in the known colourless
needles about a centimetre long. Distillation is continued as long as a cooled
sample of the distillate shews, on addition of acetone and soda lye, the known
indigo reaction. If, in this example, for the o-nitrobenzylaniline be substituted
p-nitrobenzylaniline or p-nitrobenzyl-o- or p-toluidine, p-aitrobenzaldehyde is
obtained.
The reactions of the second example are expressed by the following equations:-
CH.N: CHC,H,NO, + H2O = C,H,NH, + COH.C.H.NO,

page_text: nitrobenzylidenetoluidine
toluidine nitrobenzaldehyde
In all the above mentioned examples, for the bichromate may be substituted the
equivalent quantity of other oxidising agents, for instance ferric salts or oxidising
manganese and lead compounds.
3. MANUFACTURE OF O-NITROBENZYLALDEHYDE IN NEUTRAL SOLUTION.
23 kilos. of o-nitrobenzylaniline (or the equivalent quantity of o-nitrobenzyl-
toluidine or o-nitrobenzylxylidine) are dissolved with acetone; then an aqueous
solution, saturated in the cold, of 12.5 kilos. of potassium permanganate (or the
equivalent quantity of another permanganate or manganate) is run in, whilst
stirring quickly and cooling to about 10° C The violet colour of the permanganate
disappears quickly; the almost colourless liquid is separated from manganese by
means of a filter with pressure and introduced into a suitable distilling apparatus
to distil off the acetone.
In the retort there remains a mixture of o-nitrobenzylidene aniline and water
to which are added about 15 kilos. of hydrochloric acid (or the equivalent quantity
of another mineral acid) the whole being mixed with constaut stirring. Soon.
afterwards this mixture changes to a crystalline paste of o-nitrobenzaldehyde
with the hydrochloride of aniline in solution. The aldehyde is separated by
filtration, washed with water and if necessary, purified by distillation in a current
of steam.
In the above example for the o-nitrobenzylaniline may be substituted the equal
quantity of benzylaniline, benzyltoluidine or benzylxylidine, in order to obtain
the aldehyde; or for the o-nitrobenzylaniline may be substituted p-nitrobenzyl-.
aniline, p-nitrobenzyltoluidine or p-nitrobenzylxylidine and in this way p-nitro-
benzylaldehyde 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 aromatic aldehydes and their nitro
substitution products by oxidising benzylaniline, its homologues or nitro substitution
products and separating in the usual way by means of diluted mineral acids, the
benzylidene or nitrobenzyl compounds thus obtained into auiline bases and.
aldehyde.
2. The products manufactured as above set forth.