Improvements in the Manufacture of Guaiacol.
Year: 1893

page_text: Date of Application, 11th Mar., 1893
Complete Specification Left, 21st Nov., 1893-Accepted, 13th Jan., 1894
TRUVIDIONAL DICITIVATIO
Improvements in the Manufacture of Guaiacol.
I JAMES YATE JOHNSON of 47 Lincoln's Inn Fields in the County of Middlesex,
Gentleman do hereby declare the nature of this invention (which has been communi-
cated to me from abroad by Dr. F. Von Heyden, Nachfolger of Radebeul near
Dresden in the Kingdom of Saxony in the Empire of Germany) to be as
follows:-
It has not heretofore been possible to obtain chemically pure guaiacol from
beechwood tar and the best guaiacol obtainable in commerce the so called
"absolutely pure guaiacol" of Hartmann and Haners contains at the most only
80 per cent. of guaiacol. The remainder consists of homologues and other phenol
like matter. My foreign correspondents have discovered that guaiacol of truly
chemical purity can be obtained by proceeding as follows:-
-
Impure guaiacol such for example as creosote rich in guaiacol or the so-called
pure guaiacol of commerce is crystallised by cold or by the introduction of a
crystal of pure guaiacol.
The guaiacol alone crystallises, all the impurities remain liquid and can be
separated from the crystalline guaiacol in the usual manner (by running off,
drawing off, pressing or centrifugal action for example).
The impure guaiacol may be diluted with a neutral solvent before cooling.
The dry crystalline cakes of pure guaiacol are restored to the aggregate or liquid
condition by heat.
Dated this 11th dox of March 1893
J. H. JOHNSON & Co.,
47, Lincoln's Inn Fields, London, W.C., Agents.
COMPLETE SPECIFICATION.
Improvements in the Manufacture of Guaiacol.
I JAMES YATE JOHNSON, of 47 Lincoln's Inn Fields in the County of
Middlesex Gentleman do hereby declare the nature of this invention (which has
been communicated to me from abroad by Dr. F. Von Heyden, Nachfolger, of
Radebeul near Dresden in the Kingdom of Saxony in the Empire of Germany)
and in what manner the same is to be performed to be particularly described and
ascertained in and by the following statement :-
It has not heretofore been possible to obtain chemically pure guaiacol from
wood tar either by the methods employed by manufacturers or by operations in a
chemical laboratory. The best guaiacol obtainable in commerce the so-called
"absolutely pure guaiacol" of Hartmann and Haners contains at the most only
about 80 per cent. of guaiacol. The remainder consists of homologues and other
phenol like matter. It has now been discovered that guaiacol of truly chemical
purity can be obtained by proceeding as follows:-
Impure guaiacol wood tar or materials containing guaiacol such for example as
creosote rich in guaiacol or the so-called pure guaiacol of commerce is crystallized
by cold or by the introduction of a crystal of pure guaiacol.
When cold is employed it may be produced by means of ice or by means of a
freezing mixture or by means of a refrigerating machine for example. The

page_text: guaiacol is cooled until it crystallises and the cooling is continued until th
crystallising action ceases. The degree of cold to be employed is regulated
according to the purity of the material as the more impure qualities require
longer and more intense cooling than do the others. The guaiacol alone
crystallizes, all the impurities remain liquid and are then separated from the pure
or crystalline guaiacol by any suitable means (by running off, drawing off, pressing
or centrifugal action for example).
The impure guaiacol can also be diluted with a neutral solvent such as benzine
for example before cooling. The dry crystalline cakes of pure guaiacol may be
melted by heat and if necessary may again be distilled.
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 :-
A process for producing pure guaiacol by causing impure guaiacol or wood tar
or materials containing guaiacol to crystallize and separating the pure crystalline
guaiacol from the impurities contained in the mother liquid substantially as herein-
before described.
Dated the 21st day of November 1893.
J. H. JOHNSON & Co.,
47, Lincoln's Inn Fields, London, Agents.