Mesoporous organic-inorganic hybrid materials for separating gases

A process for preparing organic-inorganic hybrid materials with controlled porosity and functionality, comprising:

• a stage (a) of hydrolysis and polycondensation of a mixture of at least one compound of formula (I):
• Z-R1—Si(OR)(OR′)(OR″) (I)
• in which:
• Z represents either a halogen atom selected from chlorine, bromine or iodine atoms, or an amino or phosphino group;
• R, R′ and R″, which may be the same or different, independently of each other, represent an alkyl radical containing 1 to 4 carbon atoms;
• R1 represents a divalent radical derived from a saturated or unsaturated aliphatic hydrocarbon chain containing 1 to 30 carbon atoms, in which there are optionally inserted one or more structural links selected from the arylene group or the —O—, —S—, —O—C(═O)—, —N(R6)—C(═O)—or —N(R6)— fragments, in which R6 represents a hydrogen atom, an aliphatic hydrocarbon radical containing 1 to 6 carbon atoms, a benzyl radical or a phenethyl radical, said chain being unsubstituted or substituted by one or more radicals selected from the halogen atoms, the hydroxy group, alkyl radicals containing 1 to 4 carbon atoms or benzyl or phenethyl radicals;
• with at least one alkali or alkaline-earth silicate of formula (II) in a molar ratio (I)/(II)=1/9 in the presence of at least one nonionic surfactant in a micellar concentration to form a mesoporous silica represented by formula (III):
• Z-R1—Si01.59SiO2 (III)
• said stage (a) being followed
• by a step (b) of anchoring, on the mesoporous silica of formula (III), an equivalent of an organic compound represented by (Δ)N—H comprising at least one group —NH— capable of reacting with the function Z of said mesoporous silica to form the functionalized mesoporous silica represented by formula (IV):
• (Δ)N—R1—SiO1.5,9SiO2 (IV).