Process for esterifying silicon-halogen compounds in a column and apparatus suitable therefor

What is described is a process for continuously esterifying halosilanes of the formula I with alcohols of the formula II to give silane esters of the formula III in a single column (1) R1aSiHalb (I) R2-(OH) (II) R1aS-(OR2)b (III) in which R1 is hydrogen or a monovalent organic radical, where any two R1 radicals within a molecule may be different within the scope of the given definitions, Hal is a halogen atom, a plurality of Hal atoms within a molecule may be different within the scope of the given definitions, R2 is a monovalent organic radical, a and b are integers from 0 to 4 and the sum total of a and b is 4, comprising the measures of: i) feeding the total amount of the halosilane of the formula I required for the reaction in liquid form through line (6) into the upper third of the column (1), ii) feeding at least 60% by weight of the alcohol of the formula II required for the reaction in liquid form through line (7) into the upper third of the column (1), iii) feeding the remainder of the alcohol of the formula II required for the reaction in liquid form through line (8) into the lower third of the column (1), iv) conducting the reaction of the halosilane of the formula I with the alcohol of the formula II to give the silane ester of the formula III in the interior of the column (1), the temperature in the interior of the column (1) between line (7) and line (8) being below the boiling temperature of the alcohol of the formula II, v) removing the hydrogen chloride formed in the reaction via the top of the column (1), and vi) removing the esterification product of the formula III formed in the reaction from the bottom of the column (1). The invention also relates to a column (1) for continuously esterifying halosilanes of the above-described formula I with alcohols of the formula II to give silane esters of the formula III, comprising the following elements: A) line (6) which opens into the upper third of the column (1) and which serves to feed in the halosilane of the formula I, B) line (7) which opens into the upper third of the column (1) and which serves to feed in a portion of the alcohol of the formula II required for the reaction, C) line (8) which opens into the lower third of the column (1) and which serves to feed in the remaining portion of the alcohol required for the reaction, D) circulation evaporator (3) which is mounted in the lower third of the column and heats the bottom product present in the column (1), E) line (9) for removing