A method for making a hydroisomerization catalyst having improved thermal stability and metal dispersion characteristics, the catalyst prepared therefrom, and a process for making a base oil product using the catalyst are disclosed. The catalyst is prepared from a composition comprising an SSZ-91 molecular sieve and a rare earth modified alumina, with the composition being modified to contain a Group 8-10 metal, typically through impregnation of a Group 8-10 metal composition. The catalyst may be used to produce dewaxed base oil products by contacting the catalyst under hydroisomerization conditions with a hydrocarbon feedstock.

Methods are provided for performing selective hydrodesulfurization on a naphtha boiling range stream naphtha boiling range portion of a feed. It has been unexpectedly discovered that hydrodesulfurization with improved octane retention can be performed by using a catalyst that comprises CoMo supported on a catalyst support that includes a zeotype framework. By using a catalyst support including a zeotype framework, an unexpectedly high amount of octane in the naphtha boiling range portion of the hydrodesulfurized effluent is maintained.

A family of new crystalline molecular sieves designated SSZ-91 is disclosed, as are methods for making SSZ-91 and uses for SSZ-91. Molecular sieve SSZ-91 is structurally similar to sieves falling within the ZSM-48 family of molecular sieves, and is characterized as: (1) having a low degree of faulting, (2) a low aspect ratio that inhibits hydrocracking as compared to conventional ZSM-48 materials having an aspect ratio of greater than 8, and (3) is substantially phase pure.

A hydrocarbon conversion catalyst composition which comprises ZSM-48 and/or EU-2 zeolite particles and refractory oxide binder essentially free of alumina in which the average aluminium concentration of the ZSM-48 and/or EU-2 zeolite particles is at least 1.3 times the aluminium concentration at the surface of the particles, processes for preparing such catalyst compositions and processes for converting hydrocarbon feedstock with the help of such compositions.

Systems and methods are provided for conversion of a combined feed of oxygenates (such as methanol or dimethyl ether) and olefins to a high octane naphtha boiling range product with a reduced or minimized aromatics content. The oxygenate conversion can be performed under conditions that reduce or minimize hydrogen transfer. Optionally, a catalyst that further facilitates formation of branched paraffins can be used, such as a catalyst that has some type of 12-member ring site available on the catalyst surface.

A hydrocarbon conversion catalyst composition which comprises ZSM-48 and/or EU-2 zeolite particles and refractory oxide binder essentially free of alumina in which the average aluminium concentration of the ZSM-48 and/or EU-2 zeolite particles is at least 1.3 times the aluminium concentration at the surface of the particles, processes for preparing such catalyst compositions and processes for converting hydrocarbon feedstock with the help of such compositions.

A molecular sieve has a silica/alumina molar ratio of 100-300, and has a mesopore structure. One closed hysteresis loop appears in the range of P/P.sub.0=0.4-0.99 in the low temperature nitrogen gas adsorption-desorption curve, and the starting location of the closed hysteresis loop is in the range of P/P.sub.0=0.4-0.7. The catalyst formed from the molecular sieve as a solid acid not only has a good capacity of isomerization to reduce the freezing point, but also can produce a high yield of the product with a lower pour point. The process for preparing the catalyst involves steps including crystallization, filtration, calcination, and hydrothermal treatment.

A family of new crystalline molecular sieves designated SSZ-91 is disclosed, as are methods for making SSZ-91 and uses for SSZ-91. Molecular sieve SSZ-91 is structurally similar to sieves falling within the ZSM-48 family of molecular sieves, and is characterized as: (1) having a low degree of faulting, (2) a low aspect ratio that inhibits hydrocracking as compared to conventional ZSM-48 materials having an aspect ratio of greater than 8, and (3) is substantially phase pure.

A hydrocarbon conversion catalyst composition which comprises dealuminated ZSM-48 and/or EU-2 zeolite and a refractory oxide binder essentially free of alumina, processes for preparing such composition and processes for converting hydrocarbon feedstock with the help of such compositions.

A hydrocarbon conversion catalyst composition which comprises ZSM-48 and/or EU-2 zeolite particles and refractory oxide binder essentially free of alumina in which the average aluminium concentration of the ZSM-48 and/or EU-2 zeolite particles is at least 1.3 times the aluminium concentration at the surface of the particles, processes for preparing such catalyst compositions and processes for converting hydrocarbon feedstock with the help of such compositions.