Method of preparing a platinum catalyst inhibitor

A method of reacting an acetylenic alcohol with a siloxane compound having at least three silicon-bonded-hydrogen atoms bonded to at least three different silicon atoms in the presence of a platinum catalyst to provide an olefinic siloxane compound wherein the olefinic siloxane compound is an inhibitor for the platinum catalyst

• comprising continuously passing a liquid mixture of the acetylenic alcohol and the siloxane compound having at least three silicon-bonded-hydrogen atoms in the presence of a platinum catalyst through a heating means wherein the liquid mixture is heated to a temperature which is above 100.degree.C. and which is also above the temperature at which the olefinic siloxane compound is no longer an inhibitor for the reaction, but the temperature and residence time of the liquid mixture in the heating means being sufficient to produce the olefinic siloxane compound without substantial decomposition of reactants and product, said liquid mixture is under sufficient pressure to maintain the reactants and product in a liquid state at least until the mixture has passed through the heating means, said product being an olefinic siloxane compound which is, below 100.degree.C., an inhibitor for the reaction between the acetylenic alcohol and the siloxane compound having at least three silicon-bonded-hydrogen atoms in the presence of a platinum catalyst.