Improvements in the Manufacture and Production of Nitro-benzaldehydes.
Year: 1899

page_text: Date of Application, 2nd Nov., 1899
Complete Specification Laft and Avr 4000
Ancontrd
0th Cant
4000
Date of Application, 2nd Nov., 1899
Complete Specification Loft, 2nd Aug., 1000 Accepted, 9th Sept., 1000
PROVISIONAL SPECIFICATION.
Improvements in the Manufacture and Production of
Nitro-benzaldehydes.
I, JAMES YATE JOHNSON, of 47, Lincoln's Inn Fields, in the County of London,
Gentleman, do hereby declare the nature of this invention (which has been
communicated to me from abroad by the Badische Anilin & Soda Fabrik
of Ludwigshafen-on-Rhine in the German Empire) to be as follows:-
It is known that aromatic aldehydes can be prepared from the corresponding
hydro-carbons by oxidation, with the aid of various oxidising agents, for in-
stance, by treatment with chromyl-chloride, and subsequently with water, or
by chlorination and subsequent oxidation of the benzyl-compounds obtained
from the benzyl-chlorides, with chromic acid, or permanganate, and, where
necessary, splitting the resulting benzylidine compounds.
In the Specification of the German Patent No. 101221 another oxidation
process leading directly to aldehydes, is described, which consists in treating
the hydro-carbons with manganese peroxide in acid solution. These general
processes usually lead to the desired result, but when working with nitrated
hydro-carbons, a distinct difference in behaviour is noticed.
The processes
making use of chlorine can still be applied successfully to nitro-hydro-carbons,
but no process has hitherto been known, or described, by means of which nitro-
hydro-carbons can be converted into the corresponding nitro-aldehydes in a
practical manner by the aid of chromyl-chloride, or by means of a mixture of
manganese peroxide and sulphuric acid. If nitro-hydro-carbons be treated
according to the conditions of the Specification of the aforesaid German Patent,
no practically useful result is obtained. It is indeed mentioned in the said
patent that the oxidation of the nitro-toluene in this way is a matter of
difficulty, and as a matter of fact when working according to the examples
given in the specification of the said patent and using ortho-nitro-toluene, little,
or no, ortho-nitro-benzaldehyd is obtained.
The present invention consists in a process for converting ortho-
or para-nitro-toluene into the corresponding aldehydes, by 'simply heating the
said nitro compounds with manganese peroxide without the addition of an acid.
According to this new process a considerable yield of the desired aldehydes is
obtained. The process can be carried out in a vessel provided with a stirrer in
which the nitro-tolucne is heated with finely divided manganese peroxide and
under such conditions that the water produced distils off; or other means may
be adopted, for instance, the vapour of a nitro-toluene may be passed over
heated manganese-peroxide. From the distilled mixture of nitro-toluene and
nitro-benzaldehyd obtained in either case the aldehyde can be isolated by treat-
ment with sodium bisulphite.
Unchanged nitro-toluene can be used again in the same way.
The following examples will serve to further illustrate the nature of the
invention, but the invention is not confined to the examples. The parts are
by weight.

page_text: EXAMPLE 1.
Prepare a mixture of one hundred parts of ortho-nitro-toluene and sixty parts
of manganese peroxide, (containing 80 per cent. Mn O₂) in the condition of a
fine powder. Heat the mixture until it boils, and maintain the temperature for
from one to two hours. Then distil off the oil by means of steam, and treat the
distillate with an aqueous solution of sodium bisulphite at ordinary temperature
Separate the aqueous solution..of the aldehyde bisulphite compound from the
oil, and regenerate the ortho-nitro-benzaldehyd from the solution of its bisul-
phite compound by the addition of alkalies!
EXAMPLE 2.
Fill a glass, enamelled, or iron, tube with manganese peroxide, and heat it in
a bath of molten metal to a temperature of from about 210° to 250° Centigrade.
At this temperature pass the vapours of ortho-nitro-toluol through the tube which
is furnished with a condenser, so that the reaction product, and any unchanged
oil, are condensed and collected. Work up as described in Example 1.
In an analogous way the corresponding para-nitro-benzaldehyd can be pre-
pared. The manganese peroxide may be powdered native mineral, or regenerated
manganse peroxide can be used.
Dated this 2nd day of Noramhan 1000
JOHNSONS & WILLCOX.
47, Lincoln's Inn Fields, London, W.C., Agents.
Improvements in the Manufacture and Production of
Nitro-benzaldehydes.
I, JAMES YATE JOHNSON, of 47, Lincoln's Inn Fields, in the County of London,
Gentleman, do hereby declare the nature of this invention (which has been
communicated to me from abroad by the Badische Anilin & Soda Fabrik
of Ludwigshafen on Rhine in the German Empire) and in what manner the
same is to be performed to be particularly described and ascertained in and by
the following statement:-
It is known that aromatic aldehyde's can be prepared from the corresponding
hydro-carbons by oxidation with the aid of various oxidising agents for in-
stance by treatment with chromyl-chloride, and subsequently with water, or
by chlorination and subsequent oxidation of the benzyl-compounds obtained
from the benzyl-chlorides with chromic acid, or permanganate, and, where
necessary, splitting the resulting benzylidene compounds.
In the Specification of the German Patent No. 101221 another oxidation
process leading directly to aldehydes, is described, which consists in treating
the hydro-carbons with manganese peroxide in acid solution. These general
processes usually lead to the desired result, but when working with nitrated
hydro-carbons, a distinct difference in behaviour is noticed.
The processes
making use of chlorine can still be applied successfully to nitro-hydro-carbons,
but no process has hitherto been known, or described, by means of which nitro-
hydro-carbons can be converted into the corresponding nitro-aldehydes in a
practical manner by the aid of chromyl-chloride, or by means of a mixture of
manganese peroxide and sulphuric acid. If nitro-hydro-carbons be treated
according to the conditions of the Specification of the aforesaid German Patent,
no practically useful result is obtained. Indeed it is mentioned in the Specifica-

page_text: tion of the said Patent that the oxidation of the nitro-toluene, in this way, is
a matter of difficulty, and as a matter of fact, when working according to the
examples given in the specification of the said patent and using ortho-nitro-
toluene, little, or no. ortho-nitro-benzaldehyde is obtained.
The present invention consists in a process for converting ortho-nitro-toluene
or para-nitro-toluene into the corresponding aldehydes, by simply heating the
said nitro compounds with manganese peroxide without the addition of an acid.
According to this new process a considerable yield of the desired aldehyde is
obtained. The process can be carried out in a vessel provided with a stirrer in
which vessel the nitro-toluene is heated with finely divided manganese peroxide,
and under such conditions that the water produced distils off, or other means may
be employed, for instance, the vapour of the nitro-toluene may be passed over
heated manganese peroxide. From the distilled mixture of the nitro-toluene and
nitro-benzaldehyde obtained in either case, the aldehyde can be isolated by treat-
ment with sodium bisulphite.
Unchanged nitro-toluene can be used again in the same way.
The following examples will serve to further illustrate the nature of the
invention, and the manner in which it can be carried into practical effect, but the
invention is not confined to these examples. The parts are by weight.
of
EXAMPLE 1.
Prepare a mixture of one hundred parts of ortho-nitro-toluene and sixty parts
manganese peroxide (containing eighty per cent. Mn 0,) in the condition of a
fine powder. Heat the mixture until it boils. and maintain the temperature for
from one to two hours. Then distil off the oil by means of steam, and treat the
distillate with an aqueous solution of sodium bisulphite at ordinary temperature.
Senarate the aqueous solution of the aldehyde bisulphite compound from the
oil, and regenerate the ortho-nitro-benzaldehyde from the solution of its bisulphite
compound by the addition of alkalies.
EXAMPLE 2.
Fill a glass, or enamelled iron, tube with manganese peroxide, and heat it in
a bath of molten metal to a temperature of from about two hundred and ten,
to two hundred and fifty, degrees Centigrade. At this temperature pass the
vapours of ortho-nitro-toluene through the tube which is furnished with a
condenser, so that the reaction product. and any unchanged oil, are condensed
and collected. Work up as described in Example 1.
In an analogous way the corresponding para-nitro-benzaldehyde can be pre-
pared from para-nitro-toluene. The manganese peroxide may be powdered
native mineral or regenerated manganese peroxide can be used.
Having now particularly described and ascertained the nature of this in-
vention and in what manner the same is to be performed I declare that what
I claim is:-
1. The manufacture of nitro-benzaldehydes by heating ortho-nitro-toluene or
para-nitro-toluene, with manganese peroxide substantially as herein before
described.
2. The manufacture of ortho-nitro-benzaldehydes substantially as described in
the foregoing examples respectively.
Dated thin and
1000
JOHNSONS & WILLCOX,
47, Lincoln's Inn Fields, London, W.C., Agents.