maintained at the reaction temperature by means of external heating in a batchwise variant of the process the reaction mixture after it is passed through the fixed bed of catalyst is guided via an external circuit back to the catalyst and trickled over the fixed bed again this procedure is repeated until the desired degree of conversion has been reached the total residence time is thus broken down into a number of sublimes corresponding to the number of circulations irrespective of the nature of the reaction regime the reaction mixture is always broken down into its constituents by means of continuous or batchwise distillation by proceeding in accordance with the invention the glycidyloxypropyltrialkoxysilanes i are obtained in conversions of up to 100 with space time yields of up to 1 000 mol h u00b7 g pt and selectivities of up to 95 having generally described this invention a further understanding can be obtained by reference to certain specific examples which are provided herein for purposes of illustration only and are not intended to be limiting unless otherwise specified a batchwise operated tubular reactor with an external circuit which contains the catalyst bed is used to react the starting materials allyl glycidyl ether ii age and trimethoxysilane iii tmos to 3 glycidyloxypropyltrimethoxysilane i glymo a circulation pump ensures that the catalyst bed is traversed from top to bottom by the flow the catalyst employed comprises 11 2.