摘要:
Crystalline tectosilicate ZSM-5 zeolite may be prepared which comprise substantially needle-shaped agglomerates. Tectosilicate ZSM-5 zeolite having a .sup.29 Si NMR spectrum having at least three peaks indicates the presence of Si atoms in the structure having 0, 1 or 2 T-atoms as nearest neighbors.
摘要:
A molecular sieve comprising a core having deposited thereon a surface layer, wherein the core is a zeolite containing silicon and at least one element selected from gallium and iron and the surface layer has a higher Si:Al ratio than that of the silicon:selected element ratio of the core, provides for lower branching in olefin oligomerization products.
摘要:
ZSM-22 zeolite which is particularly pure and whose synthesis does not require the synthesis mixture to be stirred can be produced by the addition to the synthesis mixture of a small quantity e.g. 1000 ppm, of preformed ZSM-22 zeolite seed crystals.
摘要:
A molecular sieve comprising a core having deposited thereon a surface layer, wherein the surface layer has a higher Si:Al ratio than that of the core, provides for lower branching in olefin oligomerization products.
摘要:
ZSM-22 zeolite which is particularly pure and whose synthesis does not require the synthesis mixture to be stirred can be produced by the addition to the synthesis mixture of a small quantity e.g. 1000 ppm, of preformed ZSM-22 zeolite seed crystals.
摘要:
In a process for the oligomerization of C.sub.2 -C.sub.12 -alkenes, an alkene-containing feedstock having a water content of from 0.05 to 0.25 molar %, based on the hydrocarbon content of the feedstock, is passed over a zeolite catalyst. Improved alkene conversion and catalyst life are obtained compared to processes in which non-hydrated feedstocks are used.
摘要:
The invention is directed to methods for protecting metalloaluminophosphate molecular sieves, particularly silicoaluminophosphate (SAPO) molecular sieves, from loss of catalytic activity due to contact with a gas containing water. The methods of the invention provide procedures that enable activated sieve to contact water vapor, within a certain range of time, temperature, and water partial pressure conditions, before the sieve becomes substantially deactivated.
摘要:
The invention provides a method for converting a hydrocarbon feedstock to propylene comprising: contacting an olefinic hydrocarbon feedstock boiling in the naphtha range with a catalyst comprising a zeolitic catalyst selected from the group consisting of medium pore zeolites having a ratio of silica to alumina above 200 and pore diameter less than 0.7 nm under cracking conditions to selectively produce propylene. The preferred catalyst comprises of a zeolite having an 8, 10, or 12 membered ring pore structure. The preferred catalysts are selected from the group consisting of zeolites from the families MFI, MEL, MTW, TON, MTT, FER, MFS, and the zeolites ZSM-21, ZSM-38 and ZSM-48. Preferably the method is carried out to produce propylene with greater than 50% specificity, more preferably, the propylene to butylene ratio is at least 2:1 or a propylene to ethylene ratio of at least 4:1. The olefinic hydrocarbon feedstock consists essentially of hydrocarbons boiling within the range of 18° to 220° C. (65° F. to 430° F.). The olefinic hydrocarbon feedstock comprises from about 10 wt % to about 70 wt % olefins. Preferably the olefinic hydrocarbon feedstock comprises from about 5 wt % to about 35 wt % paraffins. The catalyst is contacted in the range of 400° C. to 700° C., a weight hourly space velocity (“WHSV”) of 1 to 1,000 hr−1 and a pressure of 0.1 to 30 atm. absolute.
摘要:
The invention provides a process for improving the conversion of a hydrocarbon feedstock to light olefins comprising the steps of first contacting the hydrocarbon feedstock with a light olefin producing cracking catalyst and subsequently thermally cracking the unseparated stream to produce additional ethylene. Preferably the zeolite catalyst is selected from the group consisting of ferrierite, heulandite, phillipsite, faujasite, chabazite, erionite, mordenite, offretite, gmelinite, analcite, ZSM-5, ZSM-11, ZSM-25, gallium silicate zeolite, zeolite Beta, zeolite rho, ZK5, titanosilicate, zeolites having a silica to alumina molar ratio within the range of about 2.0:1 to 2000:1 ferrosilicate; zeolites such as those described in U.S. Pat. No. 4,238,318; borosilicate zeolites such as those described in Belgian Pat. No. 859656; zeolites designated by the Linde Division of Union Carbide by the letters of X, Y, A, L; zeolites such as those described in U.S. Pat. No. 5,552,035; and zeolites such as those described in U.S. Pat. No. 5,348,924. Preferably the catalyst is contacted at a temperature within the range of about 500.degree. C. to about 750.degree. C. and the feedstock flows at a weight hourly space velocity in the range of about 0.1 Hr.sup.-1 WHSV to about 100 Hr.sup.-1 WHSV. The trim thermal cracking is carried out between 650.degree. C. to 900.degree. C. for 0.1 to 20 seconds.
摘要:
New titanium zeolite Beta catalysts which have been found to be useful as catalysts for the oxidation of organic compounds using organic hydroperoxides as oxidation catalysts. They are particularly useful as ring opening oxidation catalysts and may be used to produce adipic acid from cyclohexane.