PROCESS FOR THE PREPARATION OF AROMATIC URETHANES

METHODE DE PREPARATION DES URETHANES AROMATIQUES

English Abstract

ABSTRACT OF THE DISCLOSURE:
A process for the preparation of an aromatic ure-
thane of the formula:
Image
wherein Ar represents an aromatic group, substituted or not by
alkyl, alkoxy-aryl, aryl-oxy radicals and R and R' are equal
or different and each represents an alkyl radical or a hydrogen
atom, consisting in reacting an aromatic hydroxy compound with
a corresponding aliphatic urethane, preferably in the presence
of a Lewis acid catalyst and in the liquid phase. the compounds
obtained have a wide industrial application as insecticides.

Claims

The embodiments of the invention in which an exclusive
property or privilege is claimed are defined as follows:

1. A process for the preparation of an aromatic
urethane of the formula:



Image

wherein Ar represents an aromatic group, substituted or not by
alkyl, alkoxy-aryl, aryl-oxy radicals and R and R' are equal or
different and each represents an alkyl radical or a hydrogen
atom, consisting in reacting an aromatic hydroxy compound with
a corresponding aliphatic urethane in the liquid phase in the
presence of a catalyst selected among Al X3, Ti X4, Fe X3,
Zn X2 and Sn X4, wherein X represents a halogen atom, or an al-
koxy or aryl-oxy radical, at a temperature ranging between 100
and 300°C.

2. A process for the preparation of an aromatic
urethane according to claim 1, wherein the reaction is carried
out at a temperature ranging between 150 and 250°C.


3. A process for the preparation of an aromatic urethane
according to claim 1 or 2 wherein the reaction is carried out
at a phenol/urethane molar ratio ranging between 10 : 1 and
1: 10.

Description

104903;~
The present invention relates to a process for the
preparation of aromatic urethanes having the for~,ula:



Ar - O - C - N
~ R'
wherein Ar represents an aromatic group of the phenyl or naphthyl
type, substituted or not by alkyl, alkoxy, aryl, aryl-oxy
radical, and R and R' are equal or different, and each represent
an alkyl radical or a hydrogen atom.
It is known that said compounds can be synthetized from
the respective phenol and alkyl isocyanates or from aryl-cloro-
phormiates and amines by using a complex technology which entails
considerable risks due to the toxicity of the reagents employed.
It is also known that said products have a wide indus-
trial application as insecticides, some of which are particularly
interesting because they have a low animal toxicity.
It has now been found that said compounds may be
obtained by reacting aromatic hydroxy-compounds with corresponding
aliphatic urethanes in the presence of a catalyst selected among
,
Al X3, Ti X4, Fe X3, Zn X2 and Sn X4, wherein X represents a
halogen or an alkoxy or aryl-oxy radical.
The reaction is carried out in the liquid phase with
or without a solvent at a temperature ranging between 100 and
300C and preferably between 150 and 250C. The molar ratio
~ between phenol and urethane is preferably ranging between 10 : 1
`~ and 1 : 10.
The invention will be now better understood with
~, references to the following non-restrictive examples.

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1049032
EXAMPLE
At 160C and under 100 mm Hg, 14 g of alphanaphthene
were reacted with 9 g of dimethylurethane in the presence o~
0.7 g of aDhydrous Al Cl3. The reaction wa~ continued ~or 6
hours, the methanol formed during the reactlon being re ~ed.
con~erslon of 28% of naphthene was obtalned, with a practically
complete selectivity to naphthyl-methyl-urethane.
EXAMPLE 2
~ t t50C and under 100 mm Hg, 14 g of betanaphthene
were reacted with 9 g of dimethylurethane in the presence of
0.7 g Zn Cl2. A conversion of 2 % of naphthene to methyl naph-
thyl urethane was obtained.
EXAMPLE 3
:, .
At 170C and u~der 100 mm Hg, 14 g of alphanaphthene
were reacted with 18 g of dimethyl urethane in the presence of
1.5 g of titanlum tetra-~sopropylate for 5 hours. A coDYertlon
of 32% of naphthene was obta~ned, with a total selecti~lty to
methyl naphthyl urethane.