Improvements in the Manufacture or Production of Nitrile of Mandelic Acid and Mandelic Acid.
Year: 1895

page_text: Date of Application, 6th Aug., 1895
Complete Specification Left, 4th May, 1896-Accepted, 6th June, 1896
PROVISIONAL SPECIFICATION.
Improvements in the Manufacture or Production of Nitrile of
Mandelic Acid and Mandelic Acid.
A communication from abroad by the CHEMISCHE FABRIK, vormals HOFMANN &
SCHOETENSACK, of Gernsheim on the Rhine, Germany.
I, WILLIAM LLOYD WISE, of 46, Lincoln's Inn Fields, in the County of
London, Consulting Engineer and Chartered Patent Agent, do hereby declare the
nature of this invention to be as follows:-
In carrying out this invention, I agitate commercial benzaldehyde with a con-
centrated solution of the bisulphite of sodium or potassium, whereby the bisulphite
compound of the benzaldehyde is produced. This product is drained and pressed,
and if desired purified by washing in alcohol and is then mixed with water and
stirred so as to form a uniformly thin paste. To this paste is then added, all at
once, slightly more than the calculated amount of a concentrated solution of
potassium cyanide, and the mixture well stirred.
The bisulphite compound dissolves quickly, the nitrile of the mandelic acid
separating at once as a yellow oil. The latter is removed as quickly as possible
from the aqueous solution, and converted by means of hydrochloric acid into
mandelic acid. The reaction may be represented by the following equation:
=
-
:-
CH – CHO. KHSO, + KCN CH, CH(OH) – CN + K₂SO3.
The yield is quantitatively greater, and the product purer than the nitrile
produced by the methods in use heretofore.
The conversion of the nitrile into mandelic acid also takes place very readily
and is effected by agitating it with concentrated hydrochloric acid, the energy of
the reaction which takes place, being such as to cause the liquid to boil. On its
termination, the conversion of the nitrile into mandelic acid is almost complete.
The mixture is then preferably heated for some time until it boils gently and the
crude mandelic acid purified by the ordinary methods.
Dated this 6th day of August 1895.
W. LLOYD WISE,
46 Lincoln's Inn Fields, London, W.C., Chartered Patent Agent.
COMPLETE SPECIFICATION.
Improvements in the Manufacture or Production of Nitrile of
Mandelic Acid and Mandelic Acid.
A communication from abroad by the CHEMISCHE FABRIK, vormals HOFMANN
and SCHOETENSACK, of Gernsheim on the Rhine, Germany.
I, WILLIAM LLOYD WISE, of 46 Lincoln's Inn Fields, in the County of
London, Consulting Engineer and Chartered Patent Agent, 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:―
For the manufacture or production of nitrile of mandelic acid according to this

page_text: invention, commercial benzaldehyde is agitated with a concentrated solution of
bisulphite of sodium or potassium, whereby the bisulphite compound of benzaldehyde
is produced. This product is drained and pressed, and, if desired, purified by
washing in alcohol, and is then mixed with water and stirred so as to form a
uniformly thin paste. To this paste is then added, all at once, slightly more than
the calculated amount of a concentrated aqueous solution of potassium cyanide,
and the mixture produced is then well stirred. The bisulphite compound dissolves
quickly, the nitrile of the mandelic acid separating at once as a yellow oil which
is removed as quickly as possible from the aqueous solution, and is converted by
means of hydrochloric acid into mandelic acid.
The reaction may be represented by the following equation:
:-
CH – CHO. KHSO + KCN = C.H – CH(OH) – CN + K,SOg.
The yield is quantitatively greater, and the product purer than the nitrile
produced by the methods heretofore in use.
The conversion of the nitrile into mandelic acid also takes place very readily
and is effected by agitating it with concentrated hydrochloric acid, the energy of
the reaction which takes place being such as to cause the liquid to boil. On its
termination, the conversion of the nitrile into mandelic acid is almost complete.
The mixture is then preferably heated for some time until it boils gently, the
crude mandelic acid being afterwards purified by the ordinary methods.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed I declare that what I
claim is :-
1. The manufacture or production of nitrile of mandelic acid by the action of
an aqueous solution of potassium cyanide upon an alkaline bisulphite compound of
benzaldehyde, substantially as described.
2. The manufacture or production of mandelic acid from nitrile of mandelic
acid, substantially as herein described.
Deted this 4th dow of Ma- 1904
W. LLOYD WISE,
46 Lincoln's Inn Fields, London, W.C., Chartered Patent Agent.