Silanes with hydrophilic groups, their synthesis and use as surfactants in aqueous media

A method for the synthesis of silanes of the general formula ##STR16## wherein R.sup.1, R.sup.2 and R.sup.3 in a molecule are the same or different and represent aliphatic hydrocarbon groups,

• R.sup.4 is a divalent hydrocarbon group with 3 to 14 carbon atoms,
• R.sup.5 is a group having the formula --O(CH.sub.2).sub.b -- or a polyether group having the formula --(OC.sub.n H.sub.2n).sub.c --, wherein b has a value of 1 to 6, n has an average value of 2 to 2.5 and c has a value of 1 to 10,
• R.sup.6 is an --OSO.sub.3 X group or an --OR.sup.7 group, wherein X is a hydrogen, an alkali or an optionally substituted ammonium ion and R.sup.7 is an alkyl group with 1 to 4 carbon atoms or an acetyl group,
• a is 0 or 1,
• with the proviso that, when R.sup.6 represents the --OR.sup.7 group, a=1, comprising the steps of:
• a) adding, either
• (i) compounds of the general formula CH.sub.2 =CH--R.sup.8 --OH, in which R.sup.8 is a divalent aliphatic hydrocarbon group with 1 to 12 carbon atoms, in presence of a hydrosilylation catalyst and optionally c moles of an alkylene oxide of the general formula ##STR17## in presence of an alkaline catalyst or a Lewis acid, or (ii) compounds of the general formula CH.sub.2 =CH--R.sup.8 --(R.sup.5).sub.a --OH, in which R.sup.5 and R.sup.6 have the meanings already given, in presence of a hydrosilylation catalyst, or
• (iii) compounds of the general formula CH.sub.2 =CH--R.sup.8 --(R.sup.5).sub.a --OR.sup.7, in which R.sup.5, R.sup.7 and R.sup.8 have the meanings already given
• in an addition reaction to silanes of the general formula ##STR18## and b) sulfating the compounds obtained by methods (i) and (ii) above and having the formula ##STR19## and, if necessary, neutralizing with alkali hydroxide or ammonium hydroxide, and substituting the hydrogen atoms on the nitrogen.

A method of reducing the surface tension of aqueous media comprising adding an effective amount of silanes of the general formula ##STR20## wherein R.sup.1 R.sup.2 and R.sup.3 in a molecule are the same or different and represent aliphatic hydrocarbon groups,

• R.sup.4 is a divalent hydrocarbon group with 3 to 14 carbon atoms,
• R.sup.5 is a group having the formula --O(CH.sub.2).sub.b -- or a polyether group having the formula --(OC.sub.n H.sub.2n).sub.c --, wherein b has a value of 1 to 6, n has an average value of 2 to 2.5 and c has a value of 1 to 10,
• R.sup.6 is an --OSO.sub.3 X group or an --OR.sup.7 group, wherein X is a hydrogen, an alkali or an optionally substituted ammonium ion and R.sup.7 is an alkyl group with 1 to 4 carbon atoms or an acetyl group,
• a is 0 or 1,
• with the proviso that, when R.sup.6 represents the --OR.sup.7 group, a=1,
• as a hydrolysis-resistant surfactant.

An aqueous solution containing 1% by weight of silanes of the general formula ##STR21## wherein R.sup.1, R.sup.2 and R.sup.3 in a molecule are the same or different and represent aliphatic hydrocarbon groups,

• R.sup.4 is a divalent hydrocarbon group with 3 to 14 carbon atoms,
• R.sup.5 is a group having the formula --O(CH.sub.2).sub.b -- or a polyether group having the formula --(OC.sub.n H.sub.2n).sub.c --, wherein b has a value of 1 to 6, n has an average value of 2 to 2.5 and c has a value of 1 to 10,
• R.sup.6 is an --OSO.sub.3 X group or an --OR.sup.7 group, wherein X is a hydrogen, an alkali or an optionally substituted ammonium ion and R.sup.7 is an alkyl group with 1 to 4 carbon atoms or an acetyl group, and
• a is 0 or 1, with the proviso that, when R.sup.6 represents the --OR.sup.7 group, a=1,
• whereby the surface tension of the solution is reduced.