The Manufacture or Production of Carbamic Ethers.
Year: 1899

page_text: [Communicated from abroad by the FARBENFABRIKEN VORMALS FRIEDRICH BAYER & Co.,
of Elberfeld, Germany.]
The Manufacture or Production of Carbamic Ethers.
I, HENRY EDWARD NEWTON, of the Office for Patents, 6, Bream's Buildings,
Chancery Lane, in the County of London, Patent Agent, do hereby declare the nature
of this invention to be as follows:-
My foreign correspondents discovered some time since, that the carbamic acid
ethers (urethanes), derived from certain secondary alcohols, such as methylethyl-car-
binol, diethylcarbinol, methylpropylcarbinol, methylisopropylcarbinol, ethylpropyl-
carbinol, ethylisopropylcarbinol, methylbutylcarbinol, dipropylcarbinol, ethylisobutyl-
carbinol, methyl-alpha-methyl-propyl-carbinol, methyl-alphaethylpropyl-carbinol,
represent valuable soporifics, and that the said urethanes could be obtained either by
treating the respective alcohols with urea or its salts, or with carbamic chloride, or by
subjecting the chlorocarbonic acid ethers of the alcohols to the action of ammonia.
My foreign correspondents have now found, that the said urethanes can also be
obtained according to one of the following methods, viz-either by allowing
cyanogen chloride (CN.Cl), or cyanic acid (CN.OH), to act on the respective
alcohols, or by treating the neutral carbonic acid ethers of the alcohols with ammonia.
It may be remarked that, on performing the last-mentioned method of proceeding, a
better yield is obtained, if, instead of the symmetric carbonic ethers, the so-called
mixed ethers of the general formula-
(in which formula R and R¹ mean two different alkyl radicles, one of which can also
be a radicle of a primary alcohol) are used. In this case, the reaction proceeds in the
following manner, vis. -The carbonic acid ether is split, -on the one hand the
urethane corresponding to the alkyl radicle of higher molecular weight being formed,
whilst, on the other hand, the alcohol corresponding to the alkyl radicle of lower
molecular weight is obtained. Thus, for instance, on employing ethylmethylpropyl-
carbinol carbonate, the process proceeds according to the following equation:

page_text: ing the resulting ligroine solution, methylethylcarbinolurethane is obtained in the
shape of a white crystalline mass, melting at 94 degrees Centigrade.
EXAMPLE C.
A mixture prepared from 25 parts of ethyl methylpropylcarbinol carbonate of the
formula-
C₂H₂O
CO
CHS
CH,
CH.O
(which boils at about 170 degrees Centigrade) and 150 parts of a 30 per cent.
ammonia liquor, is heated while being continuously stirred for about 30 hours, at
from 90 to 100 degrees Centigrade, in a closed vessel provided with a stirring
apparatus. Subsequently, the watery solution thus produced is separated from the
small quantity of oily liquid which is likewise contained in the vessel.
From the
watery solution thus obtained, the urethane contained therein is extracted by means
of benzene. On evaporating the resulting benzene solution, the methyl-propyl-
carbinol urethane remains in the shape of a crystalline mass melting at 76 degrees
Centigrade.
The process proceeds in a manner analogous to that described in the above
examples, in case other of the hereinbefore mentioned urethanes are to be produced.
As a matter of course, my foreign correspondents do not intend to confine them-
selves to the particulars given in the examples, as these are merely typical, and can
be varied within wide limits, without altering thereby the nature of the present
invention.
Dated this 18th day of December 1899
NEWTON AND SON,
Agents for the Applicants.

page_text: The Manufacture or Production of Carbamic Ethers.
I, HENRY EDWARD NEWTON, of the Office of Patents, 6, Bream's Buildings,
Chancery Lane, in the County of London, 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 :-
My foreign correspondents discovered some time since, that the carbamic acid
ethers (urethanes) derived from certain secondary alcohols, viz., methylethylcarbinol,
diethylcarbinol, methylpropylcarbinol, methylisopropyl carbinol, ethylpropylcarbinol,
ethylisopropylcarbinol, methylbutylcarbinol, dipropylcarbinol, ethylisobutylcarbinol,
methyl-alpha-methylpropylcarbinol, methyl-alpha-ethyl-propyl-carbinol,
represent
valuable soporifics, and that the said urethanes could be obtained either by treating
the respective alcohols with urea or its salts, or with carbamic chloride, or by subjecting
the chlorocarbonic acid ethers of the alcohols to the action of ammonia.
My foreign correspondents have now found, that the said urethanes can also be
obtained according to one of the following methods, viz., either by allowing cyanogen
chloride (CN.CI) or cyanic acid (CN.OH) to act on the respective alcohols, or by
treating the neutral carbonic acid ethers of the alcohols with ammonia. It may be
remarked that in the last mentioned method of procedure, a better yield is obtained
if the so-called mixed ethers of the general formula
(in which formula R and R₁ mean two different alkyl radicles, one of which can also
be a radicle of a primary alcohol), are used instead of the symmetric carbonic ethers.
In this case, the re-action proceeds in the following manner, viz., the carbonic acid
ether is split, on the one hand, the urethane corresponding to the alkyl radicle of
higher molecular weight being formed, whilst on the other hand the alcohol
corresponding to the alkyl radicle of lower molecular weight is obtained. Thus, for
instance, on employing ethyl-methylpropylcarbinol carbonate, the process proceeds
according to the following equation :-

page_text: the mixture is saturated.
The vessel is then closed, and heated for several hours in
a water bath. Subsequently, it is allowed to cool, and again opened. The mixture is
then filtered, in order to remove the precipitate contained therein, which consists, for
the most part, of ammonium chloride. The filtrate is then heated at about 120 degrees
Centigrade, for the purpose of removing the unchanged methylpropylcarbinol
still contained therein. When the whole carbinol has distilled off, the liquid is
allowed to cool, by means of which operation it is transformed into a crystalline mass.
On extracting this mass with hot benzene, and evaporating the resulting solution,
methylpropylcarbinolurethane is obtained in the shape of a white crystalline residue
melting at 76 degrees Centigrade.
C₂H.О
CO
CH,
CH.O
CH,
(which boils at about 170 degrees Centigrade) and 150 parts of a 30 per cent.
ammonia liquor is heated, while being continuously stirred for about 30 hours, at
from 90 to 100 degrees Centigrade, in a closed vessel provided with a stirring
apparatus. Subsequently the watery solution thus produced is separated from the
small quantity of oily liquid which is likewise contained in the vessel. From the
watery solution thus obtained, the urethane contained therein is extracted by means
of benzene. On evaporating the resulting benzene solution, the methylpropyl-
carbinolurethane remains in the shape of a crystalline mass melting at 76 degrees
Centigrade.
The process proceeds in a manner analogous to that described in the above
examples, if other of the hereinbefore mentioned urethanes are to be produced.
As a matter of course, my foreign correspondents do not intend to confine them-
selves to the particulars given in the examples, as these are merely typical, and can
be varied within wide limits, without altering thereby the nature of the present
invention.
Having now particularly described and ascertained the nature of the said invention
and in what manner the same is to be performed, as communicated to me from
abroad, I declare that what claim is :-
1. The process for the production of the hereinbefore mentioned urethanes of
secondary alcohols, which process consists in subjecting the respective alcohols to the
action of cyanogen chloride (CN-CI), or cyanic acid (CN-OH), substantially as
herein before described.

page_text: 2. The process for the production of the hereinbefore mentioned urethanes of
secondary alcohols, which process consists in treating neutral carbonic acid ethers of
the respective alcohols with ammonia, substantially as herein before described.
Dated this 6th day of Santember 1000
NEWTON & SON,
Agents for the Applicant.