The Hydrothermal Synthesis of Zeolites: History and Development from the Earliest Days to the Present Time

The hydrothermal synthesis of zeolites: precursors, intermediates and reaction mechanism

The role of organic molecules in molecular sieve synthesis

A pressure applicator for applying pressure to a flowable implant material, e.g., PMMA. A pressure applicator or driver includes a pair of columns which are engageable with one another, preferably by threads to generate a driving pressure. A handle is provided for the operator to grasp and steady the device as he turns the handle to apply pressure to the implantable material within the applicator. A luer-lock or other connecting device is provided for attaching the applicator to a cannula (or a connecting conduit that in turns connects with a cannula) that will deliver the implant material to the desired site. Pressures of about 1000-3000 psi may be generated by this device.

High pressure applicator

The structure-controlling role of organic templates for the synthesis of porosils in the systems SiO2/template/H2O

Aluminosilicate zeolites are prepared containing an outer aluminum-free shell. The outer shell is essentially SiO 2 that has crystallized on the zeolite surface in the ZSM-5 type configuration, leading to a more selective catalyst.

ZSM-5 containing aluminum-free shells on its surface

As synthesized by conventional technique, zeolite ZSM-5 is crystallized in the presence of substantial amount of tetraalkylammonium cations, the alkyl groups of which contain 2 to 5 carbon atoms, such as, for example, tetrapropylammonium. When synthesized in the conventional way, ZSM-5 contains tetraalkylammonium cations as well as substantial amount of sodium ions. To obtain a more catalytically active form of ZSM-5, the sodium ions must be exchanged to very low levels. By synthesizing zeolite ZSM-5 according to the present method, i.e. in the presence of one or more diamines and with a specifically defined reaction mixture composition, ZSM-5 having different organic nitrogen-containing cations but the same crystal structure as conventionally prepared ZSM-5 is obtained. The ZSM-5 prepared in accordance hereto is very low in sodium content as synthesized.

Synthesis of zeolite zsm-5

Cationic polymers as templates in zeolite crystallization

Synthetic crystalline aluminosilicate zeolites are crystallized from an aqueous reaction mixture comprising sources of alkali metal oxide, silicate, aluminate and an ionene or ionomer which contains positively charged nitrogen atoms in such quantity as to satisfy some of the cationic sites of the eventual zeolite. The presence in the reaction mixture of such a polymer serves to direct crystallization of the zeolite, giving rise to the formation of large pore zeolites under conditions where small pore zeolites would otherwise result, to the formation of more siliceous zeolite than would otherwise result, and to the formation of certain species of zeolite essentially free of stacking faults, the crystallization of which has not heretofore been possible.

Directed crystallization of synthetic aluminosilicates

This invention provides a sorbent composition, manganese nodules with occluded sulfur, effective for removing metal contaminants from gases or liquids. It is effective for removing lead contaminant from gasoline and mercury from water or natural gas. It may be used in the chlor-alkali process for cleaning by-product hydrogen. The sorbent also may be used for recovering valuable metals, for example from mine seepage waters.

Louis D. Rollmann

Papers

ZSM-5 containing aluminum-free shells on its surface

Synthesis of zeolite zsm-5

Cationic polymers as templates in zeolite crystallization

Directed crystallization of synthetic aluminosilicates

Sorbent for removing metals from fluids