Process for producing amineoxide

An amine oxide is produced by oxidizing a tertiary amine having the formula ##STR1## wherein R.sub.1 and R.sub.2 respectively represent methyl or ethyl group; and R.sub.3 represent a C.sub.8 -C.sub.14 alkyl or alkenyl group in the presence of carbon dioxide and in the presence or absence of an improver selected from the group consisting of ethylenediaminetetraacetic acid, its salts, stanates, polyphosphates, salts of hydroxycaboxylic acid and salts of polycarboxylic acid.

BACKGROUND OF THE INVENTION 
2. Field of the Invention 
The present invention relates to an improved process for producing a 
tertiary amineoxide. More particularly, it relates to a process for 
producing a tertiary amineoxide by oxidizing a tertiary amine with 
hydrogen peroxide. 
2. Description of the Prior Arts 
It has been known that an amineoxide is produced by oxidizing a tertiary 
amine with hydrogen peroxide in the presence of a chelating agent. 
The process for producing a tertiary amineoxide by oxidizing a tertiary 
amine with hydrogen peroxide in the presence of a chelating agent of 
diethylenetriamine pentaacetic acid or it salt has been disclosed in 
Japanese Examined Patent Publication No. 14089/1976 wherein 30-75% aqueous 
solution of hydrogen peroxide has been added to the tertiary amine at 55 
to 65.degree. C. at a ratio of excess of about 10% and the reaction has 
been completed at 65.degree. to 80.degree. C. 
The process for producing a tertiary amineoxide by oxidizing a tertiary 
amine with hydrogen peroxide in the presence of sodium pyrophosphate and 
sodium bicarbonate has been disclosed in Japanese Examined Patent 
Publication 11042/1967. 
The inventors have studied on the process for producing an amineoxide by 
oxidizing a tertiary amine with hydrogen peroxide. 
SUMMARY OF THE INVENTION 
It is an object of the present invention to provide an improved process for 
producing an amineoxide by oxidizing a tertiary amine with hydrogen 
peroxide at high and constant yield for a short time. 
The foregoing and other objects of the present invention have been attained 
by oxidizing a tertiary amine with hydrogen peroxide in the presence 
0.01-2% by weight based on the amine of carbon dioxide (CO.sub.2) in the 
presence or the absence of an improver selected from the group consisting 
of ethylenediaminetetraacetic acid and its salts; stanates polyphosphates; 
salts of hydroxycarboxylic acid and salts of polycarboxylic acid. 
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
In accordance with the process of the present invention, the amount of the 
tertiary amine can be decreased to less than 0.5%. The characteristic 
feature of the present invention is to obtain the tertiary amineoxide at 
substantially constant yield for a short time by reacting a tertiary amine 
with hydrogen peroxide in carbon dioxide even though a chelating agent is 
not used because the effect of carbon dioxide is remarkably high. Such 
fact has not been considered. 
When a glass reactor is used, it is enough to use only carbon dioxide. 
However, when a metallic reactor is used, hydrogen peroxide may be 
decomposed to cause an incomplete reaction. In such case, the reaction can 
be smoothly performed to cause a complete reaction by incorporating carbon 
dioxide and a chelating additive. 
When the reaction is repeated, the reaction can be performed without the 
chelating additive by incorporating carbon dioxide even in a metallic 
reactor. 
In accordance with the process of the present invention, an amineoxide can 
be obtained at high yield without using an expensive catalyst. The safety 
is improved over the conventional process by incorporating carbon dioxide. 
The reaction of the present invention can be attained without using an 
organic solvent if desired. 
Hydrogen peroxide is preferably used as 5 to 70 wt.% of a hydrogen peroxide 
aqueous solution. 
When the concentration of hydrogen peroxide is less than 5%, a self 
decomposition of hydrogen peroxide is caused to prevent the complete 
oxidation except that a large excess of the specific additive should be 
used. 
Hydrogen peroxide can be used at a concentration of greater than 70%. 
However, the yield of the amineoxide is decreased and the feature is not 
preferable in view of the safety and the operation. 
An amount of hydrogen peroxide can be the stoichometric amount and it is 
preferable to be excess of 5 to 10% to the stoichometric amount especially 
when the conversion of the tertiary amine of more than 99% is required. 
In the oxidation, the improver is incorporated. 
Suitable improvers include ethylenediaminetetraacetic acid and its salts, 
stanate such as sodium stanate; polyphosphates such as sodium 
pyrophosphate and tripolyphosphate; salts of hydroxycarboxylic acid such 
as sodium citrate; salts of polycarboxylic acid such as sodium oxalic 
acid. 
An amount of the improver is ranging from 0.02 to 2 wt.% preferably from 
0.05 to 1 wt.% to the amine. 
An amount of carbon dioxide is ranging from 0.01 to 2 wt.% preferably 0.03 
to 1 wt.% to the amine. 
When carbon dioxide is not incorporated in the reaction system, a 
decomposition of hydrogen peroxide is caused whereby a large amount of the 
unreacted amine is remained and a reaction velocity is low. It is 
considered that carbon dioxide has certain catalytic effect in the 
oxidation. 
The method of the incorporation of carbon dioxide is not critical. Thus, it 
is preferable to add hydrogen peroxide to the amine in which carbon 
dioxide and the improver are incorporated. 
The reaction temperature is ranging from 40.degree. to 80.degree. C. 
The amines used in the process of the present invention are aliphatic 
tertiary amines having the formula 
##STR2## 
wherein R.sub.1 and R.sub.2 respectively represent methyl or ethyl group; 
R.sub.3 represents a C.sub.8 -C.sub.14 alkyl or alkenyl group. 
The typical amines used for the process of the present invention include 
N,N-dimethyl 3,7-dimethyl 2-6-octadienylamine and N,N-diethyl 3,7-dimethyl 
2-6-octadienylamine.