The present invention relates to a process for producing 5-vinylbicyclo[2.2.1]heptyltrichlorosilane which is useful as a copolymerizable monomer or modifier, etc. for organic high molecular weight compounds.
5-vinylbicyclo[2.2.1]heptyltrichlorosilane is produced by subjecting 5-vinylbicyclo[2.2.1]hepta-2-ene (II) and trichlorosilane (III) to an addition reaction (hydrosilylation) in the presence of a chloroplatinic acid catalyst [J. Gen. Chem. USSR, 31 [4], 1109-1117 (1961)]. ##STR1##
According to this process, 5-vinylbicyclo[2.2.1]heptyltrichlorosilane (I), which the addition occurs on the double bond present in the ring of the cyclic hydrocarbon, and 5-(2-trichlorosilylethyl)bicyclo-[2.2.1]hepta-2-ene (IV), which is obtained by reacting with the vinyl group outside the ring, are produced in almost equimolar amounts. In addition, the reaction yield is also as low as 35.8%. The hydrosilylation using chloroplatinic acid as the catalyst involves a significant drawback that the reaction 10 selectivity of obtaining compound (I) alone is low. Further, (I) and (IV) are structural isomers in which only the position to be added is different and, it is impossible to isolate (I) alone by distillation.
A known method for enhancing the selectivity uses trimethoxysilane instead of trichlorosilane (U.S. Pat. No. 4,100,172).
This method is characterized in that the vinyl group outside the ring is predominantly reacted with trimethoxysilane in the presence of an addition catalyst (chloroplatinic acid) to selectively give 5-(2-trimethoxysilylethyl)bicyclo[2.2.1]hepta-2-ene. However, this method is not suited for obtaining the compound having a vinyl group outside the ring which is the object of the present invention.
In the present invention, the reason why the compound having a carbon-carbon double bond at the carbon terminal such as a vinyl group and containing a reactive silyl group is necessary is because it is wished to produce a compound having a high reactivity as a modifier for organic high molecular substances and to produce a raw material having a great effect of quality modification. Namely, the carbon-carbon double bond generally shows a higher reactivity when it is present at the carbon terminal than when it is present within the ring of the cyclic hydrocarbon. For example, where a mixture of polymerizable monomers containing an alkenyl group such as ethylene, propylene, (meth)acrylic acids or (meth)acrylic acid esters, etc. and the compound described above are copolymerized with each other using a radical generator such as an organic peroxide, copolymers tend to be produced in which intake of compound (I) is larger than when the compound of formula (IV) having the double bond within the ring and the compound (I) having the vinyl group outside the ring are both present. From this tendency, a process for selectively producing the compound (I) of the present invention having a vinyl group outside the ring in a high yield has been strongly desired in view of molecular design of high molecular substances.