Improvements in the Manufacture or Preparation of Vanillin.
Year: 1895

page_text: Date of Application, 22nd Nov., 1895
Complete Specification Left, 16th July, 1896-Accepted, 22nd Aug., 1896
PROVISIONAL SPECIFICATION. -
Improvements in the Manufacture or Preparation of Vanillin.
I GEORGE WILLIAM JOHNSON of 47 Lincoln's Inn Fields in the County of
London Patent Agent do hereby declare the nature of this invention (which
has been communicated to me from abroad by C. F. Boehringer & Sochne of
Waldhof uear Mannheim in the Empire of Germany) to be as follows:
-
According to the process described in the Specification of the English Patent
No. 361, 1892 hydrolysis of the vanillin ethers typified by benzyl-vanillin is effected
by means of acids. When hydrochloric acid is employed, the reaction proceeds
according to the following equation

page_text: (1.19 specific gravity) for from 4 to 6 hours at 100° Centigrade while constantly
stirring. The alcohol is distilled off, the benzyl-ethyl-ether removed, by means of
a current of steam and the residual vanillin is then isolated which may be done
by the methods already known.
In this typical case, hydriodic or hydrobromic acid may be replaced by hydro-
chloric acid, and methylic or amylic, alcohol may be used instead of ethylic alcohol.
By a process exactly similar to the one described hydrolysis of the vanillin-ethers
typified by benzyl-vanillin may be carried out in the presence of an alcohol, for
example, methylic, ethylic, or amylic, alcohol, by means of small quantities of
sulphuric acid, vanillin being formed together with the corresponding benzyl-ether.
The following process is the most convenient :-
4 kilogrammes of benzyl-vanillin are heated in an autoclave with 8 kilogrammes
of fine pirit, 4 litres of water and 400 grammes of concentrated sulphuric acid
for six hours at 100° to 110° Centigrade. After distilling off the alcohol and
removing the benzyl-ethyl-ether in a current of steam, vanillin is isolated and
purified which may be done by the methods already known.
Dated this 22nd day of November 1895.
JOHNSONS & WILLCOX,
47 Lincoln's Inn Fields, London, W.C., Agents.

page_text: The reaction occurring takes place in two phases which are
following equations:-
expressed in the
II. CHCH₂Cl + HOC₂H¸ = CH¸CHOCH¸ + HCl.
The hydrolysis is most advantageously carried out with 20 per cent. of the
quantity of hydrochloric acid required by theory as follows:-
kilogrammes of benzyl vanillin are heated in an autoclave with 6 kilogrammes
of ethylic alcohol, 3 litres of water, and 330 grammes of hydrochloric acid
(1.19 specific gravity) for from 4 to 6 hours at 100° Centigrade while constantly
stirring. The alcohol is distilled off, the benzyl-ethyl-ether removed, by means of
a current of steam, and the residual vanillin is then isolated which may be done
by the methods already known.
In this typical case, hydriodic or hydrobromic acid may be replaced by hydro-
chloric acid, and methylic, or amylic, alcohol may be used instead of ethylic
alcohol. By a process exactly similar to the one described, hydrolysis of the
vanillin-ethers typified by benzyl-vanillin may be carried out in the presence of
an alcohol, for example, methylic, ethylic, or amylic, alcohol, by means of small
quantities of sulphuric acid, vanillin being formed together with the corresponding
benzyl ether.
The following process is the most convenient :-
4 kilogrammes of benzyl-vanillin are heated in an autoclave with 8 kilogrammes
of fine spirit, 4 litres of water and 400 grammes of concentrated sulphuric acid
for six hours at 100° to 110° Centigrade. After distilling off the alcohol and
removing the benzyl-ethyl-ether in a current of steam, vanillin is isolated and
purified which may be done by the methods already known.
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 1
claim is.-
1. In the manufacture or preparation of vanillin the hydrolysis of a vanillin ether
such as benzyl-vanillin by the reaction of an acid in the presence of an alcohol
substantially as herein before described.
2. The manufacture or preparation of vanillin in the manners hereinbefore
described in the examples.
Dated the 16th day of July 1896.
JOHNSONS & WILLCOX,
47 Lincoln's Inn Fields, London, W.C., Agents.