PROCEDIMIENTO PARA LA SINTESIS DE SILICO-ALUMINO-FOSFATOS MICROPOROSOS CRISTALINOS

LA APLICACION CONCIERNE A UN METODO MEJORADO DE PRODUCIR CATALIZADORES DE SILICO-ALUMINO-FOSFATO PARA LA CONVERSION DE METANOL EN OLEFINAS LIGERAS TALES COMO ETILENO Y PROPILENO (LA REACCION MTO). EL METODO MEJORADO DE SINTESIS SE PUEDE USAR PARA CONTROL DE LA COMPOSICION QUIMICA DE SILICO-ALUMINO-FOSFATOS, ESPECIALMENTE EL CONTENIDO EN SILICONA. EN PARTICULAR, SE HA DESCUBIERTO QUE SE PUEDEN SINTETIZAR CATALIZADORES QUE SON MAS ESTABLES A DESACTIVACION POR "CARBONIZACION", LO CUAL ES MUY IMPORTANTE PARA EL DISEÑO DE UN PROCESO MTO BASADO EN LOS SILICO-ALUMINO-FOSFATOS SINTETIZADOS. PCT No. PCT/NO92/00193 Sec. 371 Date Aug. 25, 1994 Sec. 102(e) Date Aug. 25, 1994 PCT Filed Dec. 9, 1992 PCT Pub. No. WO93/13013 PCT Pub. Date Jul. 8, 1993A process for producing crystalline microporous silico-alumino-phosphates with controlled Si content from a mixture of reactive sources of SiO2, Al2O3 and P2O5 and an organic template material, by combining at least a portion of the Al source and the P source in the absence of the Si source, mixing the resulting mixture with any remaining Al source, the Si source and the organic template material to obtain a gel, and heating the gel to obtain crystallization, wherein the Al and Si sources in the reaction mixture are mixed in the same mole ratios as in the crystalline microporous silica-alumino-phosphate to be produced, the P source is added in stoichiometric excess and hydrochloric acid is added at the same time as the P source, in a quantity such that the ratio of silica to hydrochloric acid in the gel is kept between 0.3 and 3. The invention also provides a crystalline microporous silico-alumino-phosphate produced by the process, and the use of such silico-alumino-phosphate as a catalyst for producing olefins from methanol.