IMPROVEMENTS IN THE MANUFACTURE OF SALICYLIC ACID AND OF THE HOMOLOGUES THEREOF
Year: 1884

page_text: PROVISIONAL SPECIFICATION.
カラ
I, JAMES YATE JOHNSON of 47 Lincolns Inn Fields in the County of Middlesex
Gentleman do hereby declare the nature of said Invention for "IMPROVEMENTS IN
THE MANUFACTURE OF SALICYLIC ACID AND OF THE HOMOLOGUES THEREOF
which Invention has been communicated to me from abroad by Dr Friedrich
Von Heyden of Dresden Saxony in the German Empire to be as follows:-
This Invention relating to the manufacture of Salicylic Acid and of the
homologues thereof consists as hereinafter set forth in obtaining phenyl carbonic
alkaline and salts of the alkaline earths and the homologues thereof by the action
of dry carbonic acid upon the phenolates of the alkalies and of the alkaline earths
and in the conversion of the products thus obtained into salicylic salts and the
homologues thereof by heating them in hermetically closed vessels as hereinafter
explained..
It has been ascertained by my foreign correspondent that it is possible to produce
alkaline and alkaline earth salts of acid phenylcarbonic ether and also that these
salts when heated to about from 120 to 140 Degrees Centigrade become directly
converted into normal salicylic salts without any separation of the phenol-In
this manner it becomes possible to produce one molecule of salicylic acid from one
molecule of phenol.
The manufacture of salicylic acid and of the homologues thereof is carried out
according to this Invention by means of operations conducted as next hereinafter
described.
The dry phenolate or phenolates of the alkalies or of the alkaline earths is or are
exposed preferably at the ordinary temperature of the atmosphere to the action of
dry carbonic acid until absorption takes place and there is formed the alkaline or
the alkaline earth salts of the acid carbonic phenyl ethers phenyl sodium carbonate
in particular being produced from the sodium phenol

page_text: into the simple salicylic salt proceeds without separation of phenol, the phenyl
sodium carbonate in particular being transformed into salicylate of sodium
according to the following equation.
=
C, H, O CO C₂ H₂ C O O Na
Na O
он
When the vessel is opened no excess of pressure is present, the perfectly dry,
pulverulent salicylic, salt is then dissolved in water and the salicylic acid is
precipitated by a mineral acid and purified by crystallisation in the usual
. manner.
2. The phenolate or phenolates of the alkalies and of the alkaline earths is or
are rapidly dried and placed in a vessel provided with a tight fitting cover and
dry carbonic acid is introduced into it preferably by means of a force pump so long
as may be necessary to form the phenyl carbonic salts The vessel should be kept
well cooled during this pumping or forcing operation-The vessel is kept closed so
long as the carbonic acid is not perfectly absorbed and any excess of pressure is
present-The mass is then allowed to stand for a few hours in order to admit of
the complete conversion of the phenolate into the phenyl carbonic salt. The vessel
is afterwards heated preferably in an air bath for a few hours to from about 120°
to 140° Centigrade in order to effect the conversion into normal salicylic salt or
salts.
3. The dry phenolate is placed in a vessel with an air tight cover and a sufficient
quantity of solid carbonic acid is introduced to form the phenyl carbonic salt,
the apparatus is then quickly closed and treated as herein before described with
reference to operation N° 2-The homologues of the acid are produced in the same
manner.
The vessels employed in carrying out the second and third operations herein-
before described are preferably provided with a suitable apparatus for condensing
the carbonic acid.

page_text: COMPLETE SPECIFICATION.
"
I JAMES YATE JOHNSON of 47 Lincolns Inn Fields in the County of Middlesex
Gentleman do hereby declare the nature of said Invention for "IMPROVEMENTS IN
THE MANUFACTURE OF SALICYLIC ACID AND OF THE HOMOLOGUES THEREOF
which Invention has been communicated to me from abroad by Dr Friedrich
5 Von Heyden of Dresden, Saxony in the German Empire Chemist and in what
manner the same is to be performed to be particularly described and ascertained
in and by the following statement:―
According to Kolbe, Salicylic acid is obtained technically by the action of
carbonic anhydride upon sodium phenol at a temperature of from 160° to 200°
0 centigrade The process upon which this important synthesis of salicylic acid is
based is represented by the following equation.
Sodium phenol.
Carbonic
anhydride.
Basic sodium
salicylicate.
Phenol.
In this reaction out of two molecules of phenol sodium only one molecule of salicylic
acid is obtained as a basic sodium salt the second molecule of phenol sodium
supplying the second atom of sodium for the formation of the basic salt with
simultaneous separation of phenol.
My foreign correspondent has discovered a process whereby it becomes possible
to produce one molecule of salicylic acid directly from one molecule of phenol
sodium without the aforesaid re-formation of phenol.
This process is carried out by means of the two following operations videlicet.
1. Dry carbonic anhydride is caused to pass over the absolutely dry phenolate of
the alkalies the carbonic anhydride is absorbed and the required salt of the acid
phenylcarbonic ether (esters) is formed. 2. These alkaline salts of ether are heated
to from about 100 to 120 degrees Centigrade and become directly converted
quantitatively into simple salicylic salts.
This first process proceeds according to the following equation sodium phenolate
being selected by way of illustration.

page_text: The manufacture is carried out according to this Invention by proceeding as.
hereinafter described.
I. The dry phenolate or phenolates of the alkalies or of the earthy alkalies is or
are exposed at the ordinary temperature to the action of dry carbonic acid in a
suitable vessel until absorption takes place. There is then formed quantitatively
the alkaline or the earthy alkaline salts of the acid carbonic ethers (esters).
When these salts are heated in a hermetically closed vessel or digester to from
about 120 to 140 Degrees Centigrade for a few hours the molecular transfor
mation into the simple salicylic salt proceeds quantitatively without separation of
phenol.
When the operation is completed the pressure is removed, the vessel is opened
and the perfectly dry pulverulent salicylic salt is then dissolved in water and the
salicylic acid is precipitated by a mineral acid and purified by crystallisation in the
usual manner.
II. The phenolate or phenolates of the alkalies and of the earthy alkalies is or
are rapidly dried and placed in an autoclave or vessel provided with a tight fitting
cover and dry carbonic acid is introduced into it by a force pump so long as may
be necessary to form the phenyl carbonic salts. The vessel should be kept well
cooled during this pumping or forcing operation otherwise basic salicylic sodium is
readily formed with separation of phenol.
The vessel is kept closed so long as the carbonic acid is not perfectly absorbed
and any excess of pressure is present. The mass is then allowed to stand for some
time in order to admit of the complete conversion of the phenolate into the phenyl
carbonic salt:-The vessel is then, heated in an air bath for a few hours to form
about 120° to 140° Centigrade in order to effect the conversion into normal salicylic
salt or salts.
According to a modification of this process the close vessel containing the
phenol sodium is connected by a tube provided with a valve with a vessel
containing liquid carbonic acid Under the high pressure the salt then becomes
very rapidly saturated with the required quantity of carbonic acid. When the
saturation is effected the communication with the carbonic acid vessel is shut off
and heat is applied to the close vessel containing the salt.
III The dry phenolates are placed in a vessel with an air tight cover and a
sufficient quantity of solid carbonic acid is thrown in or introduced to form the
phenyl carbonic salt the apparatus is then quickly closed and treated as herein-
before described with reference to operation No 2. The substitutions and homologues
of the acid are produced in the same manner.
Having now particularly described and ascertained the nature of the said
Invention and in what manner the same is to be performed I declare that what
I claim is
!
The process for the manufacture of phenyl carbonic alkaline and earthy alkaline
salts and the substitution phenyl carbonic alkaline salts and the homologues
thereof by the action of dry carbonic acid of the ordinary temperature or with the
employment of pressure, in conjunction with a cooling process,, upon the phenolates
and the substitution phenolates of the alkalies and of the earthy alkalies and the
conversion of the dry phenyl carbonic alkalies or earthy alkalies into salicylic salts
or substitution salicylic salts and their homologues by heating them in hermetically
closed apparatus to from about 120° to about 140° centigrade without separation
of the phenols.*