Abstract: An improved process for the catalytic partial oxidation of hydrocarbons to produce hydrogen and carbon monoxide is disclosed. The process also utilizes a novel catalyst configuration containing at least two serially aligned layers containing a noble metal or transition metal catalyst supported on a support. Alternatively the process employs only the first layer of a catalytically active metal dispersed on an inert carrier support to partially oxidize hydrocarbons.

Abstract: Low silicon sodium X zeolite containing little or no sodium A zeolite as by-product, is prepared by direct synthesis from sodium ion-containing hydrogels, the crystallization step being carried out by maintaining the hydrogels at a temperature below about 70° C., and preferably in the range of about 50 to about 70° C. for the duration of the crystallization step. Preferably, the ratios of components in the solutions used to make the hydrogel are such that in the hydrogel the silica/alumina molar ratio will be in the range of about 2.25:1 to about 2.4:1; the sodium oxide to silica molar ratio will be in the range 1.6:1 to about 1.9:1; and the water to sodium oxide molar ratio will be greater than about 60:1.

Abstract: Zeolites exchanged with lithium, rubidium, cesium cations and trivalent cations are prepared by first partially, fully or excessively ion-exchanging a sodium-containing zeolite, a potassium-containing zeolite or a sodium- and potassium-containing zeolite with trivalent cations, then calcining the partially, fully or excessively trivalent cation-exchanged zeolite, and then ion exchanging the calcined zeolite with lithium rubidium, cesium cations, thereby replacing hydrogen and any sodium and/or potassium cations remaining in the zeolite with lithium, rubidium, cesium cations, whereby trivalent cations present in the zeolite will not be substantially replaced by the lithium ions.

Abstract: Nitrogen oxides and low molecular weight hydrocarbons are removed from air by subjecting the air to a temperature swing adsorption process using as the adsorbent a composite zeolite product containing both zeolite type A and zeolite type X. The composite zeolite product is prepared by crystallizing a sodium ion- or sodium ion- and potassium ion-containing alumina-silica hydrogel under conditions which result in the production of a zeolitic composite which contains both zeolite type A and zeolite type X crystal domains. In a preferred embodiment, calcium ions constitute a substantial number of the composite's exchangeable cations and the type X portion of the composite zeolite product has a silicon-to-aluminum atomic ratio in the range of 0.9 to less than 1.15. The nitrogen oxide- and hydrocarbon-selective adsorbent can be incorporated into an atmospheric air prepurification plant downstream of a water vapor-selective adsorbent and a carbon dioxide-selective adsorbent.

Abstract: Nitrogen oxides and low molecular weight hydrocarbons are removed from air by subjecting the air to a temperature swing adsorption process using as the adsorbent a composite zeolite product containing both zeolite A and zeolite X. The composite zeolite product is preferably prepared by forming a mixture of an agglomerate of silica and sodium zeolite X having a Si/Al atomic ratio in the range of about 0.9 to less than about 1.2 and a water-soluble sodium aluminate salt; maintaining the mixture at a temperature in the range of about 25 to about 100° C. for a period of time sufficient to convert at least 50% of the silica to sodium zeolite A; and at least partially exchanging the zeolite A-containing product with divalent cations, preferably calcium ions.

Abstract: Zeolites exchanged with lithium cations and polyvalent cations are prepared by first partially ion-exchanging a sodium-containing zeolite, a potassium-containing zeolite or a sodium- and potassium-containing zeolite with polyvalent cations, then heat-treating the partially polyvalent cation-exchanged zeolite, then ion exchanging the heat-treated zeolite with ammonium cations, and then reacting the ammonium cation-exchanged zeolite with a water-soluble lithium compound under conditions which result in the removal of ammonia from the reaction zone.

Abstract: Zeolites exchanged with lithium, rubidium, cesium cations and trivalent cations are prepared by first partially, fully or excessively ion-exchanging a sodium-containing zeolite, a potassium-containing zeolite or a sodium- and potassium-containing zeolite with trivalent cations, then calcining the partially, fully or excessively trivalent cation-exchanged zeolite, and then ion exchanging the calcined zeolite with lithium rubidium, cesium cations, thereby replacing hydrogen and any sodium and/or potassium cations remaining in the zeolite with lithium, rubidium, cesium cations, whereby trivalent cations present in the zeolite will not be substantially replaced by the lithium ions.

Abstract: Novel compositions of molecular sieve adsorbents are provided in which at least 50% of the exchangeable cations are selected from those of Li, Ca, Ag and Cu and which have within their pore system metal oxide, metal oxide precursors or mixtures thereof. These compositions are useful for the separation of gases and, in particular, the separation of nitrogen from air to produce oxygen or oxygen-enriched gas.

Abstract: Chabazite, offretite, erionite, levyne, mordenite, gmelinite, zeolite A, zeolite T, EMC-2, ZSM-3, ZSM-18, ZK-5, zeolite L, and beta zeolite whose exchangeable cations are composed of 95 to 50% lithium ions, 4 to 50% of one or more of aluminum, cerium, lanthanum and mixed lanthanides and 0 to 15% of other ions are prepared by ion-exchanging the base zeolite with water-soluble trivalent ion salts and with water soluble lithium salts. The zeolites preferentially adsorb nitrogen from gas mixtures.

Abstract: Carbon dioxide is removed from gas streams comprised predominantly of gases that are less polar than carbon dioxide by passing the gas stream through a bed of type X zeolite having a silicon to aluminum atomic ratio not greater than about 1.15, thereby adsorbing the carbon dioxide from the gas stream. The process is particularly advantageous when applied to the removal of low levels of carbon dioxide from gas streams at temperatures above 20.degree. C.

Abstract: Type X zeolites whose charge-compensating cations are composed of 95 to 50% lithium ions, 4 to 50% of one or more of aluminum, cerium, lanthanum and mixed lanthanides and 0 to 15% of other ions. The zeolites preferentially adsorb nitrogen from gas mixtures.