Method of manufacturing diethylaminotrimethylsilane

Highly pure diethylaminotrimethylsilane can be manufactured in a high yield through the reaction between diethylamine and an N,O-bis(trimethylsilyl)acetamide represented by the following general formula: ##STR1## wherein X represents H or F.

FIELD OF THE INVENTION 
This invention relates to a method of manufacturing a 
diethylaminotrimethylsilane and, more particularly, to a method of 
manufacturing a highly pure diethylaminotrimethylsilane. 
BACKGROUND OF THE INVENTION 
Hitherto, diethylaminotrimethylsilane has been manufactured using a known 
method in which trimethylchlorosilane is allowed to react with 
diethylamine in the presence of a basic substance such as an amine, as 
shown by the following reaction scheme (1): 
##STR2## 
According to this method, hydrochloric acid yielded as a by-product is 
neutralized and removed in the form of a salt, such as an amine 
hydrochloride, with the aid of the basic substance (an amine) present in 
the reaction system. However, the disposal of the foregoing amine 
hydrochloride in an industrial scale was not easy. 
Also, it was difficult to remove such a salt as an amine hydrochloride 
contained as impurity in the intended product of 
diethylaminotrimethylsilane, so that the manufactured diethylam 
inotrimethylsilane was contaminated with quite a bit of chlorine ion. As a 
result, the above-described method had a serious defect that it was 
impossible to use the product for electronics materials which have 
achieved remarkable advancement in recent years. 
Therefore, it was desired to find some substitute for the above-described 
method, which enabled the production of highly pure 
diethylaminotrimethylsilane. 
As a result of our intensive studies for solving the foregoing problem, it 
has now been found that a diethylaminotrimethylsilane can be manufactured 
without contaminated by any trace of chlorine ion by the reaction of 
diethylamine with an N,O-bis(trimethylsilyl)acetamide and, what is more, 
the by-products yielded in said reaction can be reused, thus achieving 
this invention. 
SUMMARY OF THE INVENTION 
A first object of this invention is to provide a novel method of 
manufacturing a diethylaminotrimethylsilane absolutely free from chlorine 
ion. 
A second object of this invention is to provide a novel method of 
manufacturing a diethylaminotrimethylsilane wherein it is possible to 
reuse a by-product. 
The above-described objects are attained by a method of manufacturing a 
diethylaminotrimethylsilane wherein diethylamine is made to react with a 
N,O-bis(trimethylsilyl)acetamide represented by the following general 
formula: 
##STR3## 
wherein X represents H or F.

DETAILED DESCRIPTION OF THE INVENTION 
The reaction adopted in the manufacturing method of this invention is 
described below in detail. 
The N,O-bis(trimethylsilyl)acetamide is added in an amount of 1 to 2 
equivalents, preferably 1.1 to 1.4 equivalents, to diethylamine, and 
undergoes the reaction with diethylamine at a temperature from 20.degree. 
to 100.degree. C., preferably from 20.degree. to 60.degree. C. 
The foregoing reaction may be performed in the presence of a solvent, if 
needed. Suitable examples of such a solvent include those of hydrocarbon 
type, such as benzene, n-hexane, cyclohexane, etc., and those of ether 
type, such as tetrahydrofuran, dioxane, etc. However, solvents usable 
therein should not be construed as being limited to these examples. 
In the reaction of this invention, N-trimethylsilylacetamide (when X is H 
in the foregoing general formula) or N-trimethylsilyltrifluoroacetamide 
(when X is F therein) is produced as a by-product. These compounds can be 
easily converted to N,O-bis(trimethylsilyl) acetamide or 
N,O-bis(trimethylsilyl)trifluoroacetamide, respectively. Accordingly, 
these by-products can be reused to avoid not only a disposal problem but 
also a waste of resources. 
In accordance with this invention, therefore, diethylaminotrimethylsilane 
with extremely high purity can be manufactured since no chlorine is 
contained in the starting materials. As a result, it becomes possible to 
use the manufactured diethylaminotrimethylsilane for electronics materials 
including a primer for photoresists. In addition, there is no waste in 
this method since the by-products yielded can be reused for the starting 
material. 
EXAMPLES 
This invention will now be illustrated in more detail by reference to the 
following examples. However, the invention should not be construed as 
being limited to these examples. 
EXAMPLE 1 
In a 500 ml four-neck flask equipped with a stirrer, a reflux condenser, a 
dropping funnel and a thermometer, 290.3 g (1.43 mol) of 
N,O-bis(trimethylsilyl)acetamide was placed, and thereto was added 
dropwise 94.9 g (1.3 mol) of diethylamine from the dropping funnel over a 
1-hour period. During the addition, the temperature of the reaction system 
was kept within the range of 20.degree. C. to 60.degree. C. to make the 
reaction be proceeding. At the conclusion of the addition, the temperature 
was raised to 50-60.degree. C. and kept there for 2 hours, whereby the 
reaction was matured. Then, the reaction product was subjected to vacuum 
distillation. As the result of this procedure, 152 g of 
diethylaminotrimethylsilane was obtained as a fraction having a boiling 
point of 60.degree. C. under the pressure of 80 mmHg. The yield was 90%. 
The diethylaminotrimethylsilane as the foregoing fraction was examined for 
chlorine concentration (using a measuring instrument, Automatic Titrator 
GT-05, made by MITSUBISHI CHEMICAL IND. LTD.). The chlorine was not 
detected. 
EXAMPLE 2 
185 g of diethylaminotrimethylsilane was prepared in the same manner as in 
Example 1, except that 94.4 g (1.3 mol) of diethylamine was placed in the 
same flask as used in Example 1 and 340.4 g (1.4 mol) of 
N,O-bis(trimethylsilyl)trifluoroacetamide was added dropwise from the 
dropping funnel. The yield was 98%, and the chlorine was not detected. 
COMATIVE EXAMPLE 1 
In a 1 liter four-neck flask equipped with a stirrer, a reflux condenser, a 
dropping funnel and a thermometer were placed 108.5 g (1.0 mol) of 
trimethylchlorosilane, 111.1 g (1.1 mol) of triethylamine and 300 ml of 
hexane. Thereto, 73.0 g (1.0 mol) of diethylamine was added dropwise from 
the dropping funnel over a 1-hour period. During the addition, the 
temperature of the reaction system was kept within the range of 20.degree. 
C. to 60.degree. C. to make the reaction be proceeding. At the conclusion 
of the addition, the temperature was raised to 50-60.degree. C. and kept 
there for 2 hours, whereby the reaction was matured. Then, the reaction 
mixture was filtered through a glass filter to remove the salt yielded as 
a by-product. The filtrate was allowed to stand for one day at room 
temperature to precipitate the salt. The salt precipitated was filtered 
off, and the filtrate was subjected to distillation under ordinary 
pressure to obtain 136.3 g of diethylaminotrimethylsilane as a fraction 
having a boiling point of 125-126.degree. C. The yield was 94%, and the 
chlorine concentration was 146 ppm. 
From the results obtained in the foregoing examples and comparative 
example, it has proved that thechlorine contamination in the 
diethylaminotrimethylsilane obtained in accordance with this invention is 
incommensurably less than that in the diethylaminotrimethylsilane produced 
by the conventional method.