Processes for Obtaining the Two Isomeric Monomethyl-ethers of Proto-catechuic Aldehyde.
Year: 1890

page_text: Date of Application, 12th Dec., 1890
Complete Specification Left, 8th Sept., 1891-Accepted, 17th Oct., 1891
PROVISIONAL SPECIFICATION.
Processes for Obtaining the Two Isomeric Monomethyl-ethers of
Proto-catechuic Aldehyde.
I, JULIUS BERTRAM, Doctor of Philosophy, of Leipzig, in the Kingdom of
Saxony, do hereby declare the nature of this invention to be as follows:-
Starting from the supposition, that the two hydroxyls of the proto-catechuic
aldehyde possess different degrees of affinity, I have discovered the following method
of obtaining the two isomeric methyl ethers of the same.
1. If molecular quantities of the halogen-compounds of methyl (or of methyl-
sulphates of alkalies or alkaline earths) are caused to act on the dimetallic sodium
salts of proto-catechuic aldehyde, there arises the metallic compound of vanillin
(meta-methyl-ether of proto-catechuic aldehyde).
EXAMPLE FOR VANILLIN.
4.2 kilos. of proto-catechuic aldehyde and
potassium-hydrate
2.4
23
25 are dissolved in 20 kilos. of alcohol, 43 kilos. of methyl-iodide are added to the
solution, and this mixture is heated in a hermetically closed vessel to 100° Celsius
for about two hours.
The alcohol is distilled off, dilute sulphuric acid is added until neutralisation, and
the aldehydes are separated from the liquid by shaking it with ether. After the

page_text: evaporation of the ether, there remains a mixture of vanillin and proto-catechuic
aldehyde, which is separated by boiling with chloroform, the latter dissolving the
vanillin only.
The vanillin is purified by distillation in vacuo (boiling point, at 15 m pressure,
170° Centigrade, melting point 81.5° Centigrade).
EXAMPLE FOR ISO-VANILLIN.
For 42 kilos. of proto-catechuic aldehyde take only 1.7 kilos. of potassium-
hydrate, dissolve in 15 kilos. of alcohol, add 4.3 kilos of methyl-iodide and proceed
in other respects exactly as described above for the manufacture of vanillin. The
boiling temperature of iso-vanillin at 15" pressure is 179° Centigrade, its melting
point at 115 to 116 degrees.
Dated this 11th day of December 1890.
FAIRFAX & WETTER,
433, Strand, London, Agents for the Applicant.
COMPLETE SPECIFICATION.
Processes for Obtaining the Two Isomeric Monomethyl-ethers of
Proto-catechuic Aldehyde.
I, JULIUS BERTRAM, Doctor of Philosophy, of Leipzig, in the Kingdom of
Saxony, do hereby declare the nature of my invention and in what manner
the same is to be performed, to be particularly described and ascertained in and
by the following statement :-
Starting from the supposition, that the two hydroxyls of the proto-catechuic alde-
lyde possess different degrees of affinity, I have discovered the following methods
of obtaining the two isomeric methyl-ethers of the same.
1. If molecular quantities of the halogen-compounds of methyl (or of methyl-
sulphates of alkalis or alkaline earths) are caused to act on the dimetallic sodium
salts of proto-catechuic aldehyde, there arises a metallic compound of vanillin (meta-
methyl-ether of proto-catechuic aldehyde).

page_text: 4.2 kilos. of proto-catechuic aldehyde and
3.4 "
"
potassium-hydrate
are dissolved in 20 kilos. of alcohol, 4.3 kilos. of methyl-iodide are added to the
solution, and this mixture is heated in a hermetically closed vessel to 100° Celsius
for about two hours.
The alcohol is distilled off, dilute sulphuric acid is added until neutralization, and
the aldehydes are separated from the liquid by shaking it with ether. After the
evaporation of the ether, there remains a mixture of vanillin and proto-catechuic
aldehyde, which are separated by boiling with chloroform, the latter dissolving the
vanillin only.
The vanillin is purified by distillation in vacuo (boiling point, at 15 m/m pressure,
170° Centigrade, melting point 81.5° Centigrade).
EXAMPLE FOR ISO-VANILLIN.
For 42 kilos. of proto-catechuic aldehyde take only 1.7 kilos. of potassium-
hydrate, dissolve in 15 kilos. of alcohol, add 4.3 kilos. of methyl-iodide and
proceed in other respects exactly as described above for the manufacture of
vanillin. The boiling temperature of iso-vanillin at 15 / pressure is 179
Centigrade, its melting point at 115 to 116 degrees.
Having now particularly described and ascertained the nature of my said inven-
tion, and in what manner the same is to be performed, I declare that what I
claim is :-
:―
1. The manufacture of vanillin ;-
(a) By the action, either of halogen compounds of methyl, or of the methyl-
sulphates of alkalis or of alkaline earths, on dimetallic compounds of proto-
catechuic aldehyde, or
(b) By the action of sodium methylate on mono-acetyl-proto-catechuic
aldehyde.
2. The manufacture of iso-vanillin ;—
(a) By the action, either of halogen compounds of methyl, or of the methyl-
sulphates of alkalis or of alkaline earths, on monometallic compounds of
proto-catechuic aldehyde, or
(b) By the action of sodium-methylate on diacetyl-proto-catechuic aldehyde
and the treatment of the acetyl-iso-vanillin thus produced, with dilute potash
solution.
Dated this 4th day of September 1891.
FAIRFAX & WETTER,
433, Strand, London, Patent Agents.