The Production of Homologues of Vanillin.
Year: 1894

page_text: Date of Application. 24th May, 1894
Complete Specification Left. 23rd Feb., 1895-Accepted, 20th Apr., 1895
The Production of Homologues of Vanillin.
I, SYDNEY PITT, of Sutton, in the County of Surrey, Gentleman, (a commu-
nication to me from abroad by The Chemische Fabrik auf Actien (vormals
E. Schering), of 170 and 171 Müllerstrasse, Berlin,) do hereby declare the nature
of this invention to be as follows:-
It was shown in the Patent Application No. 241773 that vanillin can be obtained
from the salts of compounds of the type of p. benzolsulpho protocatechuic aldehyde,
by methylating these bodies and then splitting off vanillin from the aromatic
vanillin sulpho ethers produced, by saponification.
My correspondents have discovered that similarly the homologues of vanillin,
viz. the alkylated derivatives in the m. position of protocatechuic aldehyde may
with advantage be produced.
They have thus obtained protocatechuic aldehyde m. ethyl ether, m. propyl,
m. butyl, m. isobutyl, m. amyl, m. isoamyl ether.
1. ALKYLATION OF P. BENZOLSULPHO PROTOCATECHUIC ALDEHYDE.
The methyl halide, or the methylsulphuric acid salt used in the production of
vanillin, is replaced by the equivalent quantity of the corresponding ethyl, propyl,
butyl, isobutyl, amyl and isoamyl halides or with the ethyl, propyl, butyl, isobutyl,
amyl, and isoamyl sulphuric acid salts.
After
Example: To a solution of 40 grammes of p. benzolsulphoprotocatechuic aldehyde
and 23 grammes of ethyl iodide in 80 grammes of spirit is added 40 cubic centi
metres of an alcoholic solution of potash of 20 vol. proc. KOH, or better the
equivalent quantity of sodium ethylate and either left standing a long time at a
gentle heat or heated for a short time under pressure in a water bath.
evaporation of the spirit the residual oil is taken up with ether, and the ethereal
solution is shaken with soda solution to remove small quantities of unaltered benzol-
sulphoprotocatechuic aldehyde. After distilling off the ether, p. benzolsulphoproto-
catechuic aldehyde-m-ethyl ether remains behind as a thick oil, which after
lengthened standing solidifies into a crystalline mass.
No further purification is required for the production of the protocatechuic
aldehyde-m-ethyl ether. It crystallises out of spirit in compact crystals (melting
point 72°).
In a similar way p. benzolsulphoprotocatechuic aldehyde-m-propyl, m-butyl,
m-isobutyl, m-amyl, m-isoamyl ethers may be obtained.
2. PRODUCTION OF THE PROTOCATECHUIC ALDEHYDE-M-ALKYL ETHER.
The splitting off is best obtained by boiling with soda solution until completely
dissolved, air being excluded. The solution is then acidified and the m-alkyl ether
formed is shaken up with ether and purified by crystallising out from water.
The protocatechuic aldehyde-m-ethyl ether crystallises out of hot water, in
which it is easily soluble, in long needles which have the smell of vanillin,
(melting point 78°).
In like manner the protocatechuic aldehyde-m-propyl, m-butyl, m-isobutyl,
m-amyl, m-isoamyl ethers may be obtained. The same easily combine with alkali

page_text: derivatives soluble in water, show a blue colouring with iron chloride and are soluble
in boiling water.
Again it was shown in the Patent Application No. 2417893 that vanillin may
advantageously be produced from protocatechuic aldehyde by transforming proto-
catechuic aldehyde into its p. benzylether, methylating this and from the
benzylvanillin so formed splitting off the benzylgroup by means of hydrochloric
acid.
My correspondents have discovered that similarly the homologues of vanillin
ciz. the alkyl derivatives, in the m-position, of protocatechuic aldehyde may
advantageously be produced.
They have thus obtained protocatechuic-aldehyde-m-ethyl ether, m-propyl,
m-butyl, m-isobutyl, m-amyl, and m-isoamyl ether.
1. ALKYLATION OF THE P. BENZYLPROTOCATECHUIC ALDEHYDE.
The methyl halide or the methyl sulphuric acid salts used in the production of
vanillin from protocatechuic aldehyde is replaced by the equivalent quantity of the
corresponding ethyl, propyl, butyl, isobutyl, amyl, isoamyl halides, or by the ethyl,
propyl, butyl, isobutyl, amyl, isoamyl, sulphuric acid salts.
Example: 2.28 kilogrammes of p. benzylprotocatechuic aldehyde and 1.6 kilo-
grammes of ethyl iodide, dissolved in 10 kilogrammes of ethyl alcohol, are kept
for a few hours in a water bath with an alcoholic solution of caustic potash
containing 0.56 kilogrammes of KOH. After evaporating the spirit the small
portion of unattacked p. benzylprotocatechuic aldehyde is removed by washing the
ethereal solution of the raw product with soda solution. After evaporation of the
ether the p. benzyl-m-ethyl ether of protocatechuic aldehyde remains behind as an
easily solidifying oil. This requires no further purification for the production of
the protocatechuic aldehyde-m-ethylether.
The production of p. benzylcatechuic aldehyde m-propyl, m-butyl, m-isobutyl,
m-amyl, m-isoamyl ethers is similarly brought about.
2. PRODUCTION OF THE PROTOCATECHUIC ALDEHYDE M-ALKYL ETHERS.
Example 1 kilogramme of p. benzyl protocatechuic aldehyde-m-ethyl, or it may
be m-propyl, n-butyl, m-isobutyl, m-amyl, m-isoamyl ether, is heated in a water
bath with 50 kilogrammes of concentrated hydrochloric acid and stirred. After
separation of the benzylchloride it is oversaturated with soda solution, any small
quantity of unattacked benzylether is removed and the acidified solution shaken up
with ether; the alkyl ether then remains as a gradually solidifying oil. The same
is purified by crystallising out from water.
Dated this 24th day of May 1894.
COMPLETE SPECIFICATION.
The Production of Homologues of Vanillin.
1, SYDNEY PITT, of Sutton, in the County of Surrey, Gentleman, (a communi-
cation to me from abroad by The Chemische Fabrik auf Actien (vormals
E. Schering), of 170 and 171 Müllerstrasse, Berlin,) 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 was shown in the Patent Application No. 2417793 that vanillin can be obtained
from the salts of compounds of the type of p. benzolsulpho protocatechuic aldehyde,

page_text: by methylating these bodies and then splitting off vanillin from the aromatic vanillin
sulpho ethers produced, by saponification.
My correspondents have discovered that similarly the homologues of vanillin,
viz. the alkylated derivatives in the m. position of protocatechuic aldehyde may
with advantage be produced.
They have thus obtained protocatechuic aldehyde m. ethyl ether, and m. propyl
ether, and have found that these bodies are useful for perfumery.
1. ALKYLATION OF P. BENZOLSULPHOPROTOCATECHUIC ALDEHYDE.
The methyl halide or the methylsulphuric acid salt used in the production of
vanillin, is replaced by the equivalent quantity of the other corresponding alkyl
halides for instance ethyl and propyl halide or by the alkyl sulphuric acid salts.
Example: To a solution of 40 grammes of p. benzolsulphoprotocatechuic aldehyde
and 23 grammes of ethyl iodide in 80 grammes of spirit is added 40 cubic centi-
metres of an alcoholic solution of potash of such that 100 cubic centimetres
contain 20 grammes of caustic potash KOH, or better the equivalent quantity of
sodium ethylate and either left standing a long time at a gentle heat or heated for
a short time under pressure in a water bath. After evaporation of the spirit
the residual oil is taken up with ether, and the ethereal solution is shaken with a.
solution of sodium hydroxide to remove small quantities of unaltered benzolsulpho-
protocatechuic aldehyde. After distilling off the ether, p. benzolsulphoprotocatechuic
aldehyde-m-ethyl ether remains behind as a thick oil, which after lengthened
standing solidifies into a crystalline mass.
It crystallises out of spirit in small compact crystals (melting point 72°).
In a similar way p. benzolsulphoprotocatechuic aldehyde-m-propyl ether may be
obtained.
2. PRODUCTION OF THE PROTOCATECHUIC ALDEHYDE-M-ALKYL ETHER.
The decomposition of the p. benzolsulphoprotocatechuic-m-alkylethers is best
effected by boiling with a solution of sodium hydroxide until completely dissolved,
air being excluded. The solution is then acidified and the m-alkyl ether formed is
shaken up with ether and purified by crystallising out from water.
The protocatechuic aldehyde-m-ethyl ether crystallises out of hot water, in
which it is easily soluble, in small glittering scales which have the smell of vanillin
(melting point 77.5°).
The protocatechuic aldehyde-m-propyl ether crystallises from water into fine
needles (melting point 82°C.).
Again it was shown in the Patent Application No. 24178°3 that vanillin may
advantageously be produced from protocatechuic aldehyde by transforming proto-
catechuic aldehyde into its p. benzylether, methylating this and from the
benzylvanillin so formed splitting off the benzyl group by means of hydrochloric
acid.
My correspondents have discovered that similarly the homologues of vanillin
viz.: the alkyl derivatives, in the in-position, of protocatechuic aldehyde may
advantageously be produced.
They have thus obtained protocatechuic-aldehyde-m-ethyl and m-propyl ether.
1. ALKYLATION OF THE P. BENZYLPROTOCATECHUIC ALDEHyde.
The methyl halide or the methyl sulphuric acid salts used in the production
of vanillin from protocatechuic aldehyde is replaced by the equivalent quantity
of the corresponding alkyl halides for instance ethyl and propyl halide or by the
alkyl sulphuric acid also."
Example: 2.28 kilogrammes of p. benzylprotocatechuic aldehyde and 1.6 kilo-
grammes of ethyliodide, dissolved in 10 kilogrammes of ethyl alcohol, are kept for

page_text: a few hours in a water bath with an alcoholic solution of caustic potash containing
0-56 kilogrammes of KOH. After evaporating the spirit the small portion of
unattacked p. benzylprotocatechuic aldehyde is removed by washing the ethereal
solution of the raw product with sodium lye. After evaporation of the ether, the
p. benzyl-m-ethyl ether of protocatechuic aldehyde remains behind as an easily
solidifying oil. This ether crystallizes from spirit into small crystals (m. p. 57° C).
The production of p. benzylprotocatechuic aldehyde m-propyl ether is similarly
brought about.
The p. benzylprotocatechuic m-propyl ether crystallizes out of spirit in compact
small crystals of rhombic appearance (m. p. 74° C.).
:
1
2. PRODUCTION OF THE PROTOCATECHUIC ALDEHYDE-M-ALKYL ETHER.
Example 1 kilogramme of p. benzylprotocatechuic aldehyde-m-ethyl, or it may
be m-propyl ether, is heated in a water bath with 50 kilogrammes of concentrated
hydrochloric acid and stirred. After separation of the benzylchloride it is over-
saturated with a solution of sodium hydroxide, any small quantity of unattacked
benzylether is removed and the acidified solution shaken up with ether; the alkyl
ether then remains as a gradually solidifying oil. The same is purified by
crystallising out from water.
Protocatechuic aldehyde-m-ethyl ether crystallizes from water into small
OH (1)
Having now particularly described and ascertained the nature of any said inven-
tion and in what manner the same is to be performed I declare that what 1
claim is :-
1. As a new product the above described protocatechuic aldehyde-m-ethyl ether.
2. As a new product the above described protocatechuic aldehyde-m-propyl
ether.
3. The manufacture of protocatechuic aldehyde-m-ethyl ether substantially as
described.
4. The manufacture of protocatechuic aldehyde-m-propyl ether substantially as
described.
SYDNEY PITT.