Production of high viscosity index lubricating oil stock

A process for preparing a porous silico-crystal characterized by an X-ray diffraction pattern whose values are set forth in Table 1 of the specification which comprises:

• preparing a reaction mixture containing a source of silica, a source of trivalent metal oxide corresponding to the formula Me.sub.2 O.sub.3, an alkali metal oxide, an organic linear diquaternary ammonium compound, and water, and having a composition in terms of mole ratios falling within the following ranges:
• SiO.sub.2 Me.sub.2 O.sub.3 =100 to infinity
• H.sub.2 O/SiO.sub.2 =5 to 400
• OH/SiO.sub.2 =) to 2.0
• M.sup.+ SiO.sub.2 =0 to 2.0
• R/SiO.sub.2 =0.005 to 2.0
• wherein Me is a trivalent metal, M is an alkali metal, and R is an organic linear diquaternary ammonium compound, said organic linear diquaternary ammonium compound corresponding to the formula
• [(R').sub.3 N.sup.+ (Z).sub.m N.sup.+ (R').sub.3 ](X.sup.-).sub.2
• wherein R' is alkyl of from 1 to 20 carbon atoms, Z is a bridging member selected from the group consisting of alkyl of from 1 to 20 carbon atoms, and m is 5, 6, 8, 9 or 10.