Process for preparing layered organophosphorus inorganic polymers

#The present invention is directed to the preparation of solid inorganic polymers having organo groups anchored to the surfaces of the polymers. The majority of the polymers formed are layered crystals which display intercalation activity.

#The interface surfaces of solids are responsive regions of chemical and physical action. In many practical chemical and physical phenomena such as absorption, corrosion inhibition, heterogeneous catalysis, lubrication, ion exchange activity, adhesion and wetting and electrochemistry activity occurs as a consequence of the presence of a definable solid surface. Solid agents are preferred in most processes over solution or homogeneously dispersed reactive alternatives primarily because they greatly simplify efficient separation of products from reactants. However, solids invariably suffer from deficiencies in activity and selectivity in the conversions they effect, due to inherent heterogeneity in their active sites which arises from the nature of their surface structure. Furthermore, much of the active sites are usually buried within the surface, and as a result of these two factors, elevated temperature and low conversions are typically encountered. Exceptions in which homogeneous catalysts are employed have been the Monsanto process for the production of acetic acid from methanol and carbon monoxide employing rhodium, the production of linear alcohols from olefins and syngas, ethylene oxidation of the wacker process, catalysis of olefins to form polymers, and other polymerization systems.

#In an effort to achieve the best features of both homogeneous and heterogeneous processes, efforts have been made to chemically "anchor" known effective solution agents such as phosphines, nitriles, cyclopentadiene and the like, onto certain solids. Porous inorganic surfaces and insoluble organic polymers have been employed. Silica has been the inorganic of choice, the bonded ligand being attached by reaction with the --OH groups projecting from the surface. The organic polymer most used has been polystyrene, with an appropriate metal-coordinating function bonded via the phenyl rings. Results have been generally encouraging. However, there have been pervasive problems deriving from the non-uniform situation of sites which has manifested itself in loss of expected selectivity, activity and even in attrition.

#FIG. 1 illustrates a layered microcrystal. Each lamellar slab is formed of strong covalent bonds and has a thickness of about 10 atoms.

#FIG. 2 illustrates intercalation where the interlayer distance is shown as "d."

#FIG. 3 illustrates the accepted structure for zirconium phosphate and spacing between layers. The dashed lines between zirconium (Zr) atoms is to establish the plane between them. In the drawing P=Phosphorus, O=Oxygen and water of hydration is shown.

#According to the present invention there is provided a process for the production of inorganic polymers in layered crystalline to amorphous state by the liquid phase metathesis reaction of at least one organophosphorus acid compound having the formula:

#[(HO).sub.2 OP].sub.n R

#wherein n is 1 or 2 and R is an organo group covalently coupled to the phosphorus atom with at least one tetravalent metal ion selected from the group consisting of zirconium, thorium, cerium, uranium, lead and titanium to form a solid inorganic polymer precipitate in which phosphorus is linked to the metal by oxygen and the organo group is covalently bonded to the phosphorus atom. When n is 1, the organo groups will be pendant from phosphorus atoms. When n is 2, cross-linking will occur between interlamellar surfaces of the crystalline end produced. Typically, the tetravalent metal ion is provided as a soluble salt MX wherein M is as defined above and X is the anion(s) of the salt. Typical anions include halides, HSO.sub.4.sup.-1, SO.sub.4.sup.-2, O.sub.2 C--CH.sub.3.sup.-1, NO.sub.3.sup.-1, O.sup.-2 and the like.