Improvements in the Manufacture of Salicylic-esters called "Salols."
Year: 1887

page_text: Date of Application, 22nd July, 1887
Complete Left, 23rd Apr., 1888
Complete Accepted, 1st June, 1888
Improvements in the Manufacture of Salicylic-esters called
"Salols."
I, CARL KOLBE of Radebeul near Dresden, in the Kingdom of Saxony, German
Empire, Manufacturer, do hereby declare the nature of this invention to be as
follows:-
Salol has heretofore been obtained by treating salicylic acid and phenol, or,
salicylate of sodium and phenol, or salicylate of soda and phenate of sodium with
phosphoric oxychloride P.O. Cl, or with phosphoric pentachloride P Cl..
Experiments have led to the following results:
I. Instead of using phosphoric oxychloride P. OC, or phosphoric pentachloride
P. Cl, there may be employed phosphorous chloride P. Cl₂, or sulphuric chloride
S.O₂ C, may be used with advantage, as well as acid and poly acid sulphates of the
alkalies."
If phosphorous chloride P Cl₂ be allowed to flow into a melted mixture of
1 equivalent of salicylic acid and 1 equivalent of phenol, salol is obtained mixed
with triphenylphosphite P (OC, H₁), which is an oily body that can be easily
removed on account of its ready solubility in alcohol.
If it be desired to produce salol by means of sulphuric chloride S.O., Cl.,, it is
preferable to employ salicylate of sodium and phenol or phenate of sodium.
If acid sulphates of the alkalies, which have a strong affinity for water, be heated
with a mixture of salicylic acid and phenol, salol is produced according to the
following equation :

page_text: Disalol C H
-0-06
0-0-0-0
OH
may be produced by the action of phosphoric oxychloride P.O Cl, upon a melted
mixture of equivalent quantities of salol and salicylic acid, or of a mixture of
2 equivalents of salicylic acid and 1 equivalent of phenol. In the latter case the
amount of the phosphoric oxychloride P.O Cl, eniployed must be doubled. The
liquid product of the re-action is washed with a solution of soda and re-crystallized
with hot alcohol. The disalol separates as an oil on the cooling of the alcohol. If
the salol in this process be replaced with gaultheria oil, gaultheric salol
OH
will be obtained, which may be still better prepared by the action of phosphoric 4
oxychloride PO Cl, upon salicylate of sodium and gaultheria oil.
For this purpose two or four equivalents of salicylate of sodium are mixed with two
equivalents of gaultheria oil and a suitable quantity of benzol. To this mixture

page_text: is added 1 equivalent of phosphoric oxychloride PO Cl₂, and the reaction completed
by heating in a vessel, a cooler being used by which the volatilized products are
returned to the vessel after being cooled and condensed. The resulting product is
treated with a solution of soda whereby free salicylic acid finally forms a watery
solution; and the gaultheric salol is obtained, after the benzol has been removed
by distillation, by recrystallization from alcohol.
A similar process may be advantageously employed for the production of nitro-salols
from nitro-salicylic acids and phenols or nitro-phenols. For example: 4 equivalents
of nitro-salicylate of sodium and 2 equivalents of phenol are heated in a water bath
with a suitable quantity of benzol and 1 equivalent of phosphoric oxychloride PO Cl..
The nitro-acid which separates, is filtered off; the benzol is distilled from the filtrate,
and the remaining product is re-crystallized from alcohol.
The properties of the compounds thus produced are similar to those of salol. The
melting points of some of the most important salols are :
CARL KOLBE.
Per W. Lloyd Wise,
46, Lincoln's Inn Fields, London, W.C.,
Agent for the Applicant.

page_text: Improvements in the Manufacture of Salicylic-esters called
"Salols."
I, CARL KOLBE, of Radebeul, near Dresden, in the Kingdom of Saxony, German
Empire, 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:
Salol has heretofore been obtained by treating salicylic acid and phenol, or salicylate
of sodium and phenol, or salicylate of soda and phenate of sodium with phosphoric
oxychloride PO Cl, or with phosphoric pentachloride P Cl..
Experiments have however led to the following results:
I. Instead of using phosphoric oxychloride PO Cl₂, or phosphoric pentachloride P Cl,,
there may be employed phosphorous chloride P C; or sulphuric chloride SO, Cl₂,
may be used with advantage, as well as acid and poly acid sulphates of the alkalies.
If phosphorous chloride Cl, be allowed to flow into a melted mixture of 1 equi-
valent of salicylic acid and 1 equivalent of phenol, salol is obtained mixed with
triphenylphosphite P (OC, H), which is an oily body that can be easily removed, on
account of its ready solubility in alcohol.
If it be desired to produce salol by means of sulphuric chloride SO, Cl₂, it is
preferable to employ the aforesaid proportions of salicylate of sodium and of phenol
or phenate of sodium at any suitable temperature.
If a sufficient quantity of acid sulphates of the alkalies, which have a strong
affinity for water be heated with the mixture of one equivalent of salicylic acid and
one equivalent of phenol, salol is produced according to the following equation
Other dehydrating salts produce ketones.
In all processes for the production of salol heretofore carried on with the help of
phosphoric oxychloride and phosphoric pentachloride, as well as in the processes
herein described, a solvent or diluting agent may be added to the mixture of salicylic
acid and phenol or to the mixture of their salts, in order to effect a better or more
complete reaction. Substances particularly suitable for this purpose are hydrocarbons
such as benzol, toluol, and mineral oil having a high boiling point.
When all the phosphoric oxychloride PO Cl, phosphorous chloride P (l,,
phosphoric pentachloride, sulphuric oxychloride, or the acid or poly acid sulphate of

page_text: an alkali as the case may be, has reacted, the solvent is removed by distillation and
the residual salol is washed with water or soda, and when necessary is re-crystallized
from alcohol.
II. Instead of using salicylic acid other acids for example alpha oxynaphthoic acid
ortho- and para-nitrosalicylic acid, and resorcin carbon acid, may be employed.
Also instead of using phenol, other compounds similar to phenol may be employed
for example-resorcin, pyrogallol, thymol, nitrophenol, a- and B-naphthol, dioxy-
naphthalene, gaultheria oil (CH, COO H2) OH and salol (C, H, COO C, H.) OH,
or instead of this salol a mixture requisite for the production of the same as for
example salicylic acid, phenol, and a cliloride of phosphorous may be employed.
These substances are treated in the same way as that described above with
reference to salicylic acid and phenol. The following examples will illustrate this
process.
Resorcin disalicylate (CH, COO), C, H, is produced by treating a melted
OH 2
mixture of 1 equivalent of resorcin and 2 equivalents of salicylic acid with phosphoric
oxychloride PO Cl, at about 120° C.
The resulting product forms on cooling a vitreous mass that can be readily purified
by re-crystallization from alcohol.
The monosalicylate of resorcin may be obtained by heating 1 equivalent of resorcin
and 1 equivalent of salicylic acid with phosphoric oxychloride PO Cl. In this case
it is preferable not to melt these substances together, but to dissolve them in toluol.
The resulting resorein monosalicylate is mixed to some extent with the disalicylate,
4 OH
will be obtained, which may be still better prepared by the action of phosphoric
oxychloride PO Cl, upon salicylate of sodium and gaultheria oil.
For this purpose two or four equivalents of salicylate of sodium are mixed with two
equivalents of gaultheria oil and a suitable quantity of benzol. To this mixture is
added 1 equivalent of phosphoric oxychloride PO Cl₂, and the reaction completed by
heating by means of a return current cooler or reflux condenser. The resulting
product is treated with a solution of soda whereby free salicylic acid finally forms
an aqueous solution, and the gaultheric salol is obtained, after the benzol has been
removed by distillation, by recrystallization from alcohol.
A similar process may be advantageously employed for the production of nitro-
salols from nitro salicylic acids and phenols or nitro-phenols. For example:
4 equivalents of nitro-salicylate of sodium and 2 equivalents of phenol are heated in
a water bath with a suitable quantity of benzol and 1 equivalent of phosphoric
oxychloride PO Cl. The nitro-acid which separates, is filtered off; the benzol is
distilled from the filtrate, and the remaining product is re-crystallized from alcohol.

page_text: The properties of the compounds thus produced are similar to those of salol. The
melting points of some of the most important salols are:
a naphthylsalicylate CH, COO C₁, H₂
10
OH
ẞ "
"
"
resorcinmonosalicylate C. H. COO C, H, OH
OH
COO
resorcindisalicylate (CH C00) C. H.
2
gaultheric salol C, H, COO C, H, COO CH₂
он
4
pyrogallyl salicylate C, H, COO C, H, (OH),
он
Phenyl-u-oxynaphthol CIO H. COO C₂ H₂
6
он
CH, COO CH-1
OH
NO₂
phenyl ortho nitro salicylate
3
COO C H-1
phenylparanitrosalicylate C, H, OH
2
NO₂
COO C₂ H₂ NO₂
p-nitrophenylsalicylate CHOH
disalol C. H
COO C10 H13
thymolsalicylate C, H, OH
он
COO CH, COO C₂ H₂
oit
B-naphthyl-a-oxynaphthoat C₁ H
COO C₁0 H,
10
O.H
ẞ-naphthohydrochinonsalicylate (C, HA COH),
COO CE
phenylresorcincarbon acid ester C₂ H3 (OH),
The products obtained by the above mentioned pr
duction of colors.
Having now particularly described and ascertained
and in what manner the same is to be per
m is:
--
The several processes substantially as hereinal
ducing salols by treating salicylic acid or alpha
a-nitrosalicylic acid, or resorcin carbon acid an
ogallol, thymol, nitro-phenol, a- and B-napthol, di
alol (or in lieu of the latter the mixture for its pr

page_text: phenol and a chloride) with phosphorous chloride (P Cl₂) or with sulphuric chloride
(SO, Cl₂) or with an acid or poly acid sulphates of an alkali.
2. In the production of "salols" as referred to in the preceding claim the use of
a solvent or diluting medium preferably a hydrocarbon such as benzol, toluol or
mineral oil having a high boiling point substantially as herein described.
3. In the production of "salols" by the aid of phosphoric pentachloride or
phosphoric oxychloride the use of a solvent or diluting medium such as benzol, toluol
or a mineral oil having a high boiling point, substantially as herein described.
4. The several processes substantially as hereinabove respectively described for
producing salols by treating alpha oxynapthoic acid, or otho- or para-nitrosalicylic
acid, or resorcin carbon acid, and napthol, resorcin, pyrogallol, thymol, nitro phenol,
a- and B-napthol, dioxynapthalene, gaultheria oil, or salol (or in lieu of the latter
the mixture for its production such as salicylic acid, phenol and a chloride) with
phosphoric pentachloride, or with phosphoric oxychloride.
5. The several new or improved salols or products hereinabove respectively
denominated
a naphthylsalicylate; ẞ naphthylsalicylate; resorcinmonosalicylate; resorcindi-
salicylate; gaulthericsalol; pyrogallyl salicylate; phenyl-a-oxynaphthol; phenyl-
orthonitrosalicylate; phenylparanitrosalicylate; p-nitrophenylsalicylate; thymol-
salicylate; disalol; B-naphthyl-a-oxynaphthoic B-naphthohydrochinonsalicylate;
phenylresorcincarbonacid ester.
Dated this 23rd day of April 1000.
W. LLOYD WISE,
46, Lincoln's Inn Fields, London, W.C.,
Agent for the Applicant.