Manufacture of Meta-amido Benzaldehyde and of Salts thereof.
Year: 1891

page_text: Date of Application, 29th June, 1891
Complete Specification, Left, 28th Mar., 1892-Accepted, 30th Apr., 1892
PROVISIONAL SPECIFICATION.
[Communicated from abroad by THE FARBWERKE VORMALS MEISTER LUCIUS
AND BRUNING, of Hoechst a/ Main, Germany, Chemical Manufacturers.]
Manufacture of Meta-amido Benzaldehyde and of Salts thereof.
I, OLIVER IMRAY of No. 28 Southampton Buildings, Chancery Lane, in the
County of London, Fellow of the Institute of Patent Agents, do hereby declare
the nature of this invention to be as follows:-
It is well known to chemists that the reduction of meta-nitro benzaldehyde into
meta-amido benzaldehyde is a very difficult thing. Up to the present time only
one way of reducing meta-nitro-benzaldehyde is known, namely by treatment with
stannous chloride and hydro chloric acid. (Tiemann and Ludwig Ber. d. deutsch
ch. Ges. XV 2044.) Gabriel (Ber. d. deutsch ch. Ges. XVI 1999) has tried in vain
to arrive at the meta-amido-benzaldehyde by reduction of the nitro-aldehyde by
means of green vitriol (ferrous-sulphate) and ammonia. In fact meta-amido-benz-
aldehyde is a body not known yet.
My foreign correspondents have discovered that the bisulphite compound of the
meta-nitro-benzaldehyde can be easily reduced, opening thereby the way to the
industrial production of the meta-amido-benzaldehyde.
The bisulphite compound of the nitro-benzaldehyde is converted into the
bisulphite compound of the meta-amido-benzaldehyde by any of the usual reducing
agents, such conversion being effected directly when a solution thereof together
with an excess of bisulphite is left standing for some considerable time, or more
quickly, with somewhat violent reaction, on being heated.
The reduction of the bisulphite compound is effected more easily when submitted
to the action of dilute mineral acid and iron or zinc and especially under the action
of green vitriol and alkali.
The invention may be, for example, carried out in the following manner:
27 parts by weight of meta-nitro-benzaldehyde are dissolved in
60 parts by weight of bisulphite solution containing 30 per cent. of NaHSO3
and 250 parts by weight of water.
For the reduction of this solution are employed iron and sulphuric acid
(Example a) or green vitriol and soda (Example b).
EXAMPLE a.
The solution of the bisulphite compound is brought into a vessel with a stirrer
and thereto are added 50 parts by weight of iron filings and, by degrees (distributed
over a day,) 90 parts by weight of sulphuric acid of 66° Bé. diluted with 200 parts
by weight of water. The temperature is kept all the time at from 30 to 40° C. for
which generally the heat developed in the reaction will be sufficient. Having
added the last portions of the acid, the temperature is raised to from 40 to 50° C.
until the entire quantity of iron has passed into solution and a sample is found free
of nitro-aldehyde. The solution is then filtered off, the filtrate accurately
neutralized by means of about 90 parts by weight of soda, heated to boiling
point and pressed off hot. The further treatment will be described at the end of
example
EXAMPLE b.

page_text: by weight of water, and this solution is heated to boiling point; there is then
added the solution of the bisulphite compound prepared in manner hereinbefore
set forth, and the hot solution is mixed with a solution of 130 parts by weight
of calcined soda. It is boiled for a short time until the reduction is finished.
The solution is filtered off from the precipitate of hydroxide of iron at boiling
temperature.
The liquids obtained in the two examples are acidulated with sulphuric or
hydrochloric acid and boiled until the elimination of the SO, is effected.
There results an acid solution of meta-amido-benzaldehyde, the standard of which
can be easily ascertained by titration with nitrite.
For most industrial purposes the solution will be employed as it is, thus it
may be used for example for the production of meta-oxy, or meta-chloro-benz-
aldehyde.
But it is quite easy to separate the meta-amido benzaldehyde in the form of an
internal condensation product, by rendering alkaline the acid solution or mixing it
with acetate of soda. In this way will be obtained a flocculent slightly yellow
colored precipitate, which is filtered off, washed and dried. It consists of the con-
densation product of meta-amido benzaldehyde and furnishes with mineral acids the
salts of the aldehyde.
According to the experience of my foreign correspondents, the meta-amido-
benzaldehyde cannot be isolated. Freed from its salts, it passes over in its nascent
state into a non oxygenised base.
This base is of very difficult solubility in alcohol, and scarcely soluble in water
and ether. From alcohol the body crystallises in the form of felted needles.
The analysis gave as the simplest expression of its composition: C'H'N. The
body only melts at a very high temperature, assuming dark coloration.
It possesses
pronounced basic qualities and with mineral acids forms the salts of meta-amido-
benzaldehyde when heated with mineral acids and tertiary bases, it yields meta-
amido-tetralkyl-diamido-triphenyl-methanes.
Dated this 29th day of June 1891.
ABEL & IMRAY,
Agents for the Applicant.
COMPLETE SPECIFICATION.
Manufacture of Meta-amido Benzaldehyde and of Salts thereof.
I, OLIVER IMRAY of No. 28 Southampton Buildings, Chancery Lane, in the
County of London, Fellow of the Institute of Patent Agents, 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:-
It is well known to chemists that the reduction of meta-nitro benzaldehyde into
meta-amido-benzaldehyde is a very difficult thing. Up to the present time only
one way of reducing meta-nitro-benzaldehyde is known, namely by treatment with
stannous chloride and hydrochloric acid. (Tiemann and Ludwig Ber. d. deutsch
ch. Ges. XV 2044.) Gabriel (Ber. d. deutsch ch. Ges. XVI 1999) has tried in vain
to arrive at the meta-amido-benzaldehyde by reduction of the nitro-aldehyde by
means of green vitriol (ferrous-sulphate) and ammonia. In fact meta-amido-
benzaldehyde is a body not known yet.
My foreign correspondents have discovered that the bisulphite compound of the
meta-nitro-benzaldehyde can be easily reduced, opening thereby the way to the
industrial production of the meta-amido-benzaldehyde.
The bisulphite compound of the nitro-benzaldehyde is converted into the bi-
sulphite compound of the meta-amido-benzaldehyde by any of the usual reducing
agents, such conversion being effected directly when a solution thereof together
with an excess of bisulphite is left standing for some considerable time or more
quickly, with somewhat violent reaction, on being heated.

page_text: 680 parts by weight of green vitriol are dissolved in 2000 parts by weight of
water; the solution is stirred together with 250 parts by weight of carbonate of
lime and added to the solution of neta-nitro-benzaldehyde in bisulphite prepared as
hereinbefore set forth. The nitro-body is reduced immediately while CO₂ is
formed.
The liquids obtained in the three examples are acidulated with sulphuric or
hydrochloric acid and boiled until the elimination of the SO, is effected.
There results an acid solution of meta-amido-benzaldehyde, the standard of which
can be easily ascertained by titration with nitrite.
For most industrial purposes, the solution will be employed as it is, thus it may
be used, for example, for the production of meta-oxy or meta-chloro-benzaldehyde.
But it is quite easy to separate the meta-amido-benzaldehyde in the form of an
internal condensation product, by rendering alkaline the acid solution or mixing it
with acetate of soda. In this way will be obtained a flocculent slightly yellow
colored precipitate, which is filtered off, washed and dried. It consists of a con-
densation product of meta-amido-benzaldehyde and furnishes with mineral acids the
salts of the aldehyde.
According to the experience of my foreign correspondents, the meta-amido-
benzaldehyde cannot be isolated. Freed from its salts, it passes over in its nascent
state into a non-oxygenised base.
This base is of very difficult solubility in alcohol, and scarcely soluble in water

page_text: and ether. From alcohol the body crystallises in the form of felted needles. The
analysis gave as the simplest expression of its composition C,H,N. The body
only melts at a very high temperature, assuming dark coloration. It possesses
pronounced basic qualities and with mineral acids forms the salts of meta-amido-
benzaldehyde when heated with mineral acids and tertiary bases, it yields meta-
amido-tetralkyl-diamido-triphenyl methanes.
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 :-
1. The production of meta-amido-benzaldehyde or its salts by treating the
bisulphite compound of the meta-nitro-benzaldehyde with reducing agents, such as
zinc or iron and mineral acids or ferrous oxide salts and alkali or green vitriol and
carbonate of lime or sulphites.
2. The meta-amido-benzaldehyde or its salts produced as above set forth.
This oth 1 CM 1005
ABEL & IMRAY,
Agents for the Applicant