The present application pertains to family of new crystalline molecular sieves designated SSZ-92. Molecular sieve SSZ-92 is structurally similar to sieves falling within the ZSM-48 family of molecular sieves and is characterized as having magnesium.

Disclosed are processes for conversion of a feedstock comprising C.sub.8+ aromatic hydrocarbons to lighter aromatic products in which the feedstock and optionally hydrogen are contacted in the presence of the catalyst composition under conversion conditions effective to dealkylate and transalkylate said C.sub.8+ aromatic hydrocarbons to produce said lighter aromatic products comprising benzene, toluene and xylene. The catalyst composition comprises a zeolite, a first metal, and a second metal, and is treated with a source of sulfur and/or a source of steam.

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.

Catalyst composition useful in the catalytic dewaxing of a waxy hydrocarbon feedstock which catalyst composition includes a mixture of zeolite EU-2 and titania and may further include a noble metal. The zeolite EU-2 has a molar bulk ratio of silica-to-alumina (SAR) of greater than 100:1. The zeolite or mixture may have been dealuminated such as by acid leaching using a fluorosilicate salt or by steam treating.

Described are processes to produce base oils with one more improved properties, e.g., lower aromatics, economically and/or efficiently. In some embodiments the processes comprise a step that reduces the amount of residual refractory sulfur compounds prior to or simultaneous with a hydrofinishing step which advantageously provides base oils with lower aromatics than comparable processes.

A catalyst system for dewaxing of a hydrocarbon feedstock comprising at least two catalytic sections, the first section comprising a first dewaxing catalyst and a subsequent section comprising a second dewaxing catalyst, wherein the first dewaxing catalyst is a ZSM-12 zeolite based catalyst and the second dewaxing catalyst is a EU-2 and/or ZSM-48 zeolite based catalyst. The catalyst system displays enhanced performance when compared to systems containing either ony ZSM-12 based catalyst or EU-2/ZSM-48 based catalyst only.

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.

An improved hydroisomerization catalyst and process for making a base oil product using a catalyst comprising SSZ-91 molecular sieve and ZSM-12 molecular sieve. The catalyst and process generally involves the use of a catalyst comprising an SSZ-91 molecular sieve combined with a ZSM-12 molecular sieve to produce dewaxed base oil products by contacting the catalyst with a hydrocarbon feedstock. The catalyst and process provide improved base oil cold properties, such as pour point and cloud point, along with other beneficial base oil properties.

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.

An improved hydroisomerization catalyst and process for making a base oil product wherein the catalyst comprises a base extrudate that includes SSZ-91 molecular sieve and a high nanopore volume alumina. The catalyst and process generally involves the use of a SSZ-91/high nanopore volume alumina based catalyst to produce dewaxed base oil products by contacting the catalyst with a hydrocarbon feedstock. The catalyst base extrudate advantageously comprises an alumina having a pore volume in the 11-20 nm pore diameter range of 0.05 to 1.0 cc/g, with the base extrudate formed from SSZ-91 and the alumina having a total pore volume in the 2-50 nm pore diameter range of 0.12 to 1.80 cc/g. The catalyst and process provide improved base oil yield with reduced gas and fuels production.