Provided herein is a unique process that prepares a saturated hydrocarbon mixture with well-controlled structural characteristics that address the performance requirements driven by the stricter environmental and fuel economy regulations for automotive engine oils. The process allows for the branching characteristics of the hydrocarbon molecules to be controlled so as to consistently provide a composition that has a surprising CCS viscosity at −35° C. (ASTM D5329) and Noack volatility (ASTM D5800) relationship. The process comprises providing a specific olefinic feedstock, oligomerizing in the presence of a BF.sub.3 catalyst, and hydroisomerizing in the presence of a noble-metal impregnated, 10-member ring zeolite catalyst.

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.

Provided herein is a unique process that prepares a saturated hydrocarbon mixture with well-controlled structural characteristics that address the performance requirements driven by the stricter environmental and fuel economy regulations for automotive engine oils. The process allows for the branching characteristics of the hydrocarbon molecules to be controlled so as to consistently provide a composition that has a surprising CCS viscosity at 35 C. (ASTM D5329) and Noack volatility (ASTM D5800) relationship. The process comprises providing a specific olefinic feedstock, oligomerizing in the presence of a BF.sub.3 catalyst, and hydroisomerizing in the presence of a noble-metal impregnated, 10-member ring zeolite catalyst.

An improved hydroisomerization catalyst system and process for making a base oil product using a combined catalyst system comprising SSZ-91 molecular sieve and SSZ-95 molecular sieve. The catalyst system and process generally involves the use of a catalyst comprising an SSZ-91 molecular sieve and a separate catalyst comprising an SSZ-95 molecular sieve to produce dewaxed base oil products by sequentially contacting the catalysts with a hydrocarbon feedstock. The catalyst system and process provide improved base oil yield along with other beneficial base oil properties.

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.

Methods are provided for forming noble metal catalysts comprising both platinum and a second Group VIII metal, such as palladium, with improved aromatic saturation activity. Instead of impregnating a catalyst with both platinum and another Group VIII metal at the same time, a sequential impregnation can be used, with the Group VIII metal being impregnated prior to platinum. It has been discovered that by forming a Group VIII metal-impregnated catalyst first, and then impregnating with platinum, the distribution of platinum throughout the catalyst can be improved. The improved distribution of platinum can result in a catalyst with enhanced aromatic saturation activity relative to a catalyst with a similar composition formed by simultaneous impregnation.

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.