The invention provides a novel class of organosilicon compounds which are hydrogenalkenyloxysilanes represented by the general formula ##STR1## in which R.sup.1 is a monovalent hydrocarbon group having from 1 to 8 carbon atoms, R.sup.2, R.sup.3 and R.sup.4 are each a hydrogen atom or a monovalent hydrocarbon group having from 1 to 8 carbon atoms and n is a number of zero, 1 or 2. The silane compounds are readily obtained by the dehydrochlorination reaction between a corresponding hydrogen-containing chlorosilane compound and an .alpha., .beta.-unsaturated aldehyde compound or a ketone compound in the presence of an acid acceptor. The compounds are useful as a modifying agent in the silicone technology and also serve as a curing agent.

BACKGROUND OF THE INVENTION 
The present invention relates to a novel class of organosilicon compounds 
hitherto unknown and useful for the modification of various silicone 
materials as well as for accelerating curing of crosslinkable silicone 
materials. The invention also relates to a method for the preparation of 
the above novel organosilicon compounds. 
SUMMARY OF THE INVENTION 
The novel organosilicon compound of the invention is a 
hydrogenalkenyloxysilane represented by the general formula 
##STR2## 
in which R.sup.1 is a monovalent hydrocarbon group having from 1 to 8 
carbon atoms, R.sup.2, R.sup.3 and R.sup.4 are each independently a 
hydrogen atom or a monovalent hydrocarbon group having from 1 to 8 carbon 
atoms and n is a number of zero, 1 or 2. 
The above defined hydroalkenyloxysilane is readily synthesized by the 
dehydrohalogenation reaction of a corresponding hydrogenhalogenosilane 
compound and an .alpha.,.beta.-unsaturated aldehyde compound or a ketone 
compound in the presence of an acid acceptor. 
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
The inventive hydrogenalkenyloxysilane defined above is a novel compound 
hitherto unknown and not described in any literatures. The compound is 
represented by the above given general formula (I) in which R.sup.1 is a 
monovalent hydrocarbon group having from 1 to 8 carbon atoms exemplified 
by alkyl groups such as methyl, ethyl, propyl, butyl and octyl group, 
alkenyl groups such as vinyl and allyl groups, aryl groups such as phenyl 
and tolyl groups and aralkyl groups such as benzyl and phenylethyl groups 
as well as those groups derived from the above named hydrocarbon groups by 
the substitution with halogen atoms or cyano groups and the like for part 
or all of the hydrogen atoms therein. Needless to say, the group R.sup.1 
is not essential when the number n is equal to 3. 
The groups represented by R.sup.2, R.sup.3 and R.sup.4 are each a hydrogen 
atom or a monovalent hydrocarbon group having from 1 to 8 carbon atoms 
similar to those groups given for R.sup.1 above. These groups can be the 
same ones or may be different from each other in a molecule. 
Among numbers of the hydrogenalkenyloxysilanes in conformity with the 
general formula (I) and the definitions of the symbols, following 
particular compounds are prepared most easily and with high yields: 
##STR3## 
The inventive hydrogenalkenyloxysilane is readily synthesized by the 
dehydrohalogenation reaction, e.g. dehydrochlorination reaction between a 
corresponding hydrogen-containing chlorosilane compound and an 
.alpha.,.beta.-unsaturated aldehyde compound or a ketone compound in the 
presence of an acid acceptor such as triethylamine at an elevated 
temperature with high yield. 
In carrying out the above reaction, it is recommended to use the 
hydrogen-containing halogenosilane in an amount of not exceeding the 
equimolar amount to the aldehyde or ketone compound in order to obtain the 
desired product in a good yield relative to the starting silane compound. 
Further, the acid acceptor should be used in an amount in excess of 
equimolar. It is of course optional, if necessary, that the reaction 
mixture is diluted with a suitable organic solvent such as aromatic 
hydrocarbons, e.g. benzene, toluene and xylene, sliphatic hydrocarbons, 
e.g. hexane and pentane, and halogenated hydrocarbons, e.g. 
dichloroethane, trichloroethylene and perchloroethylene. It is sometimes 
recommended to use an excessive amount of the same aldehyde or ketone 
compound as that used as the reactant so as that the excess amount of the 
aldehyde or ketone may serve as a diluent of the reaction mixture. The 
reaction is usually carried out at a temperature in the range from 
30.degree. to 130.degree. C. or, preferably, from 50.degree. to 80.degree. 
C. taking 6 to 8 hours. An excessively high temperature over 130.degree. 
C. is undesirable due to the decrease in the yield of the desired product. 
The hydrogenalkenyloxysilane of the invention is particularly useful as a 
modifying agent for various silicone materials or used as a curing agent. 
For example, the inventive silane compound reacts with an aliphatically 
unsaturated organic compound in the presence of a platinum catalyst by the 
addition reaction to give an alkenyloxysilyl adduct compound. The 
inventive silane compound is also useful for the modification of an 
organic polymer containing unsaturated groups with a silicone to give a 
modified polymer capable of being cured by the action of moisture in the 
presence of a trace amount of a catalyst.

Following are the examples to illustrate the inventive silane compounds and 
the method for the preparation thereof in further detail. 
EXAMPLE 1 
Into a reaction vessel were introduced 697 g (12 moles) of acetone and 608 
g (6.0 moles) of triethylamine to form a reaction mixture into which 230 g 
(2.0 moles) of methyldichlorosilane were added dropwise over a period of 2 
hours while keeping the temperature of the reaction mixture not to exceed 
60.degree. C. by cooling from outside. 
After completion of addition of the silane compound, the reaction mixture 
was heated under reflux at about 60.degree. C. for 2 hours to effect the 
reaction with precipitation of the hydrochloride of triethylamine. The 
triethylamine hydrochloride was removed by filtration and the filtrate was 
subjected to distillation under reduced pressure to give 269 g of a 
fraction boiling at 65.degree. C. under a pressure of 85 mmHg. 
The above obtained liquid product was identified by infrared absorption 
spectral analysis, mass spectrometric analysis, elementary analysis and 
NMR analysis (data given below) to be a hydrogenalkenyloxysilane expressed 
by the structural formula given below. The yield was about 85% of the 
theoretical value based on the amount of the starting silane compound used 
in the reaction. 
##STR4## 
Infrared absorption spectral analysis: 
##STR5## 
Molecular weight by mass spectrometry: 158 (calculated molecular weight as 
C.sub.7 H.sub.14 O.sub.2 Si 158) 
Elementary analysis: 
______________________________________ 
Calculated Found, 
as C.sub.7 H.sub.14 O.sub.2 Si, % 
% 
______________________________________ 
Si 17.75 17.78 
C 53.12 53.10 
H 8.92 8.94 
______________________________________ 
NMR analysis: 
______________________________________ 
.delta. value 
______________________________________ 
Si--CH.sub.3 0.28 
Si--H 4.75 
C.dbd.CH.sub.2 4.08 
--CH.sub.3 1.76 
______________________________________ 
EXAMPLE 2 
The experimental procedure was substantially the same as in Example 1 
except that the methyldichlorosilane was replaced with 203 g (1.5 moles) 
of trichlorosilane to give 160 g of a liquid product boiling at 43.degree. 
C. under a pressure of 6 mmHg. 
This liquid product was identified by the results of analyses given below 
to be a hydrogenalkenyloxysilane expressed by the structural formula given 
below. The yield was about 80% of the theoretical value based on the 
amount of the starting silane compound used in the reaction. 
##STR6## 
Infrared absorption spectral analysis: 
##STR7## 
Molecular weight by mass spectrometry: 200 (calculated molecular weight as 
C.sub.9 H.sub.16 O.sub.3 Si 200) 
Elementary analysis: 
______________________________________ 
Calculated as 
C.sub.9 H.sub.16 O.sub.3 Si, % 
Found, % 
______________________________________ 
Si 14.02 14.06 
C 53.96 53.93 
H 8.05 8.04 
______________________________________ 
NMR analysis: 
______________________________________ 
.delta. value 
______________________________________ 
CH.sub.3 
1.62 
##STR8## 
4.01 
##STR9## 
4.34 
______________________________________ 
EXAMPLE 3 
Into a reaction vessel were introduced 275 g (4.73 moles) of acetone and 
240 g (2.37 moles) of triethylamine to form a reaction mixture into which 
150 g (1.58 moles) of dimethylchlorosilane were added dropwise over a 
period of 1 hour. After completion of addition of the silane, the reaction 
mixture was heated for 6 hours at about 60.degree. C. to effect the 
reaction with precipitation of the hydrochloride of triethylamine. The 
triethylamine hydrochloride was removed by filtration and the filtrate was 
subjected to distillation to give 80 g of a liquid product boiling at 
74.degree. C. under atmospheric pressure. 
The results of analyses shown below undertaken with this product indicated 
that this compound was a hydrogen alkenyloxysilane expressed by the 
structural formula below. The yield was about 43% of the theoretical value 
based on the amount of the starting silane compound used in the reaction. 
##STR10## 
Infrared absorption spectral analysis: 
##STR11## 
Molecular weight by mass spectrometry: 116 (calculated molecular weight as 
C.sub.5 H.sub.12 OSi 116) 
Elementary analysis: 
______________________________________ 
Calculated as 
C.sub.5 H.sub.12 OSi, % 
Found, % 
______________________________________ 
Si 24.17 24.15 
C 51.66 51.60 
H 10.41 10.38 
______________________________________ 
NMR analysis: 
______________________________________ 
.delta. value 
______________________________________ 
##STR12## 
0.25 
##STR13## 
4.80 
##STR14## 
3.86 
CH.sub.3 
1.75 
______________________________________ 
EXAMPLE 4 
The experimental procedure was substantially the same as in Example 1 
except that acetone was replaced with 697 g (8.1 moles) of diethylketone 
to give 257 g of a liquid product boiling at 86.degree. C. under a 
pressure of 13 mmHg. 
The results of analyses given below undertaken with this liquid product 
indicated that the product was a hydrogenalkenyloxysilane expressed by the 
structural formula given below. The yield was about 60% of the theoretical 
value based on the amount of the starting silane compound used in the 
reaction. 
##STR15## 
Infrared absorption spectral analysis: 
##STR16## 
Molecular weight by mass spectrometry: 214 (calculated molecular weight as 
C.sub.11 H.sub.22 O.sub.2 Si 214) 
Elementary analysis: 
______________________________________ 
Calculated as 
C.sub.11 H.sub.22 O.sub.2 Si, % 
Found, % 
______________________________________ 
Si 13.10 13.13 
C 61.63 61.68 
H 10.34 10.30 
______________________________________