Manufacture of a New Product from Ionone or Pseudo-ionone.
Year: 1897

page_text: PROVISIONAL SPECIFICATION.
Manufacture of a New Product from Ionone or Pseudo-ionone.
I, EDGAR DE LAIRE, of 92, Rue St. Charles, Paris, in the Republic of France,
Director of the Society of de Lire & Co., do hereby declare the nature of this
invention to be as follows :-
In the Specification No. 8736 of 1893 Tiemann has shown that pseudo-ionone
(CHO) is converted by the action of acids into an isomeric ketone, which he
has called ionone, having the same formula C₁,HO and possessing an odour of
violets.
In the Specification No. 22114 of 1893 Tiemann has further shewn that compounds
of the citral series (to which belongs pseudo-ionone, formed by the condensation of
citral with acetone under the influence of alkaline reagents) are converted into
isomerides by the action of acid condensing agents.
He has specified the use of various acid condensing agents for effecting these
changes, for example, sulphuric acid of various degrees of concentration. In the
Specification No. 22114 of 1893 he has quoted examples of isomerisations effected
with sulphuric acid containing 60 per cent. and 70 per cent. of H₂SO-
When pseudo-ionone is treated with acids (chiefly sulphuric acid) of greater or
less concentration, it is converted into ionone, the transformation being more or less
complete according to the quantity of acid employed, the temperature of the
reaction and the duration of the process.
I have found that if, when concentrated acids are employed, the temperature of
the reaction be allowed to approach that at which decomposition, resinification or
complete carbonisation, sets in, or if the action of the acid be allowed to proceed
for a sufficiently long time, there will be found among the products of the
reaction, besides ionone, oils the boiling points and specific gravities of which are
slightly higher than those of ionone.
When pseudo-ionone is treated with dilute acids this phenomenon is but little
noticeable but when, for example, sulphuric acid containing 80 per cent. H₂SO
is used, the change can be realised with certainty.
I have observed that under these conditions the ionone which is formed in an
early stage of the reaction can be transformed, by pursuing this same reaction,
more or less completely into an isomeride.
This isomeride, which I call "iso-ionone" can be obtained in a pure state from
ionone by operating as follows:-'
One part of ionone is slowly added, drop by drop and with constant stirring, to
3 or 4 parts of well cooled ordinary commercial sulphuric acid (66° B). The
temperature of the mixture is allowed to reach 30° C.
The whole is then poured into water, the solution is extracted by a suitable
solvent (ether, for example) and the solution thus obtained is washed and
neutralised with a little sodium carbonate or sodium hydroxide solution.
The solvent is distilled off and the residue from the distillation is subjected to a
rapid current of steam to separate from the resins the unaltered ionone and the
iso-ionone produced.

page_text: The mixture of ionone and iso-ionone thus obtained is fractionally distilled and
the portion distilling off between 135° and 145° C. at a pressure of 18 mm. is
collected as "crude iso-ionone."
This substance can be further purified by renewed fractional distillation and also
by the following method:-
The crude iso-ionone is dissolved in alcohol and an aqueous solution of
semicarbazide hydrochloride containing an excess of sodium acetate is added to
the alcoholic solution (a little more than one equivalent of semicarbazide hydro-
chloride in proportion to the iso-ionone should be used). The semicarbazone of
iso-ionone CH20 N.NH.CO.NH₁₂, presently separates in the form of crystals.
By recrystallising several times from alcohol, the semicarbazone of ionone is easily
separated for it is more soluble and crystallises less easily than that of
iso-ionone.
By treating the semi-carbazone of iso-ionone for some time with dilute sulphuric
acid in a solution of ether and alcohol it is decomposed into semi-carbazide sulphate
and iso-ionone, and this latter is isolated in the known manner.
The boiling point of pure iso-ionone is about 140° C. at a pressure of 18 mm.
The specific gravity of the compound is 0.946 at 17° C. and the index of refraction
is p
1.521.
=
The melting point of the parabromo-phenylhydrazone of iso-ionone is 114° to
115° C.; that of the semi-carbazone of iso-ionone is 148° C.
The melting point of the parabromophenyl-hydrazone of ionone, on the other
hand, is 142° to 143° C., and that of the semi-carbazone of ionone is 110° to 112° C.
Iso-ionone has an odour similar to that of ionone, and, like the latter, should find
application in perfumery, confectionery and distilleries, etc.
Iso-ionone is like ionone, optically inactive.
As Tiemann has shewn in the Specification No. 8736 of 1893 and as I have also
said pseudo-ionone is converted by acids first into ionone. It follows that in the
manufacture of iso-ionone for the ionone used as the raw material may be substituted
the same proportion of pseudo-ionone, the rest of the procedure being as I have
set forth.
By the action of hydriodic acid at a high temperature, iso-ionone is converted,
like ionone under the same conditions, into a hydrocarbon of the formula C₁3H18.
This hydrocarbon, when attacked by powerful oxidising agents (potassium perman-
ganate, for example) yields an acid of the formula C₁₂H₁₂O melting at 214° C.
Dated this 14th day of October 1897.
ABEL & IMRAY,
Agents for the Applicant.
Manufacture of a New Product from Ionone, or Pseudo-ionone.
I, EDGAR DE LAIRE, of 92, Rue St. Charles, Paris, in the Republic of France,
Director of the Society of de Laire & Co., do hereby declare the nature of this inven-
tion 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. 8736 of 1893 Tiemann has shewn that pseudo-ionone
(CHO) is converted by the action of acids into an isomeric ketone, which he
has called ionone, having the same formula C₁, H2O and possessing an odour of
violets.
In the Specification No. 22114 of 1893 Tiemann has further shewn that com-
pounds of the citral series (to which belongs pseudo-ionone, formed by the conden-

page_text: sation of citral with acetone under the influence of alkaline reagents) are converted
into isomerides by the action of acid condensing agents.
He has specified the use of various acid condensing agents for effecting these
changes, for example, sulphuric acid of various degrees of concentration.
In the Specification No. 22114 of 1893, he has quoted examples of isomerisations
effected with sulphuric acid containing 60 per cent. and 70 per cent. of H₂SO.
When pseudo-ionone is treated with acids (chiefly sulphuric acid) of greater or
less concentration, it is converted into ionone, the transformation being more or
less complete according to the quantity of acid employed, the temperature of the
reaction and the duration of the process.
I have found that if, wheu concentrated acids are employed, the temperature of
the reaction be allowed to approach that at which decomposition, resinification or
complete carbonisation, set in, or if the action of the acid be allowed to proceed for
a sufficiently long time, there will be found among the products of the reaction
of the acids on the pseudo-ionone, besides ionone, oils the boiling points and
specific gravities of which are slightly higher than those of ionone.
When pseudoionone is treated with dilute acids this phenomenon is but little
noticeable but when, for example, sulphuric acid containing 80 per cent. of H₂SO.
is used, the change can be realised with certainty.
I have observed that under these conditions the ionone which is formed in an
early stage of the reaction can be transformed, by pursuing this same reaction,
more or less completely into an isomer.
This isomer, which I call "iso-ionone" can be obtained in a pure state from the
ionone of Tiemann's Specification No. 9736 of 1893 by operating as follows:-
One part of ionone is slowly added, drop by drop and with constant stirring, to
3 or 4 parts of well cooled ordinary commercial sulphuric acid (66° B.). The
temperature of the mixture is allowed to reach 30° C.
The whole is then poured into water, the solution is extracted by a suitable
solvent (ether, for example) and the solution thus obtained is washed and
neutralised with a little sodium carbonate or sodium hydroxide solution.
The solvent is distilled off and the residue from the distillation is subjected to a
rapid current of steam to separate from the resins the unaltered ionone and the
iso-ionone produced.
The mixture of ionone and iso-ionone thus obtained is fractionally distilled and
the portion distilling off between 135° and 145° C. at a pressure of 18 mm. is
collected as
" crude iso-ionone."
This substance can be further purified by renewed fractional distillation and
also by the following method :-
The crude iso-ionone is dissolved in alcohol and an aqueous solution of semi-
carbazide hydrochloride containing an excess of sodium acetate is added to the
alcoholic solution (a little more than one equivalent of semicarbazide hydrochloride
in proportion to the iso-ionone should be used). The semicarbazone of iso-ionone
CHN.NH.CO.NH,, presently separates in the form of crystals. By
recrystallising several times from alcohol, the semicarbazone of ionone is easily
separated for it is more soluble and crystallises less easily than that of iso-
ionone.
By treating the semi-carbazone of iso-ionone for some time with dilute sulphuric
acid in a solution of ether and alcohol it is decomposed into semicarbazide sulphate
and iso-ionone, and this latter is isolated in the known manner.
As stated above, when pseudo-ionone is treated with dilute acid but little
iso-ionone is formed in addition to the ionone. Some, however, is generally formed
and commercial ionone ordinarily contains iso-ionone, the proportion of which is
greater the more concentrated the acid used in converting the pseudo-ionone into
ionone. The presence of the iso-ionone in the ionone is recognisable in the following
manner.
The semicarbazone of the mixture of ionone and iso-ionone to be tested is
prepared in the manner just indicated.

page_text: This crude semicarbazone, which is obtained in the form of an oil is then purified
in the following manner:
It is dissolved in ligroine and the crystals deposited in the ligroine are dissolved
in alcohol. The alcoholic solution as it is cooled deposits crystals, which after
several crystallisations fuse at 148° C. If the ligroine solution of the semicar-
bazone deposits crystals too slowly, it generally suffices to evaporate the ligroine
and then to crystallise in alcohol the semicarbazone residue of the evaporation, in-
the same way as the crystals would be treated. When these crystals are
decomposed by the method already indicated they yield the iso-ionone.
When the concentrated alcoholic solution of the crude semicarbazone (obtained
from commercial ionone) no longer deposits crystals when it is cooled, the alcohol
is evaporated and an oily mass is obtained which consists for the greater part of
the semicarbazone of ionone. This is decomposed by the action of sulphuric acid
in an alcoholic solution and the ionone thus obtained is converted into its oxime.
The oxime is dissolved in ligroin and the solution is strongly cooled whereupon the
oxime separates in crystals which melt at 88-89° C. By heating the crystallised
oxime with a dilute acid (dilute sulphuric acid, for example) pure ionone is
obtained.
The boiling point of pure iso-ionone is about 1270-128.5° C. at a pressure of
10 m.m. and 134.5°-135.5° at 145 mm. pressure. The specific gravity of the
compound is 0.946 at 17° C. and the index of refraction is n = 1.521.
The melting point of the parabromophenylhydrazone of iso-ionone is 114°
to 115° C.; that of the semi-carbazone of iso-ionone is 148° C.
The melting point of the parabromophenylhydrazone of ionone, on the other
hand, is 142° to 143° C., and that of the semicarbazone of ionone is 107°-109° C.
When ionone is highly purified and contains no polymeric compounds (such
ionone may be prepared from the crystallised oxime of ionone), it has properties
which differ still more widely from those of iso-ionone than do those of ordinary
ionone. It distils at 123°-124° C. At a pressure of 11 mm., its specific gravity
is 0.932 and its index of refraction is n₁ = 1.498.
As already stated, the oxime of ionone, prepared in the ordinary manner in a
solution acidulated with acetic acid, crystallises when a concentrated solution of it
in ligroin is strongly cooled. It then melts at 880-89° C. and yields highly purified
ionone when decomposed by the usual means.
I have not found it possible, on the other hand, to crystallise the oxime of
iso-ionone in the same way.
:
Iso-ionone has an odour similar to that of ionone, and, like the latter, should find
application in perfumery, confectionery and distilleries, etc.
Iso-ionone is like ionone, optically inactive.
t
Since iso-ionone is only a variety of ionone it is preferable not to retain for it the
name iso-ionone which I have given to it in my Provisional Specification.
It is better to call the form of which the parabromophenylhydrazone melts
at 142°-143° C., a-ionone, and the form of which the parabromophenylhydrazone
melts at 114° -115° C. and the semi-carbazone at 1480 C., B-ionone.
As Tiemann has shewn in the Specification No. 8736 of 1893 and I have also said
It follows that in the
pseudo-ionone is converted by acids first into ionone.
manufacture of iso-ionone for the ionone used as the raw material may be substituted
the same proportion of pseudo-ionone, the rest of the procedure being as I have set forth.
By the action of hydriodic acid at a high temperature, iso-ionone is converted,
like ionone under the same conditions, into a hydrocarbon of the formula C₁3H18-
This hydrocarbon, when attacked by powerful oxidising agents (potassium
permanganate, for example) yields an acid of the formula C₁₁₂O melting
at 214° C.
12
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
Lina innana on Rinnane by treating ionone or a-ionone, or

page_text: pseudo-ionone (the two compounds characterised in Tiemann's Specification
No. 8736 of 1893) with acid more or less concentrated, substantially as
described.
2. The iso-ionone or 8-ionone produced as above set forth.