A process for producing paraxylene by the catalytic alkylation of benzene and/or toluene with methanol, which produces a para-rich mixture of xylene isomers, together with water and some light organic by-products, particularly dimethyl ether and C.sub.4 olefins. The off-gas stream, containing the C.sub.4 olefins, may be recycled back to the reaction to be co-injected with methanol to reduce the methanol self-decomposition and the reaction of methanol to olefins or to fluidize catalyst particles recovered by a reactor cyclone. By using recycled off-gas rather than water or steam, the deleterious effects of water and/or steam on the catalyst aging and activity rates and the size of downstream equipment necessary to recover olefin by-products may be reduced.

The present disclosure provides methods and materials for oligomerization of lower olefins (e.g., C.sub.2-C.sub.8) to transportations fuels including diesel and/or jet fuel. The oligomerization employs, in certain embodiments, tungstated zirconium catalysts. Surprisingly, the oligomerizations proceed smoothly in high yields and exhibit little to no sensitivity to the presence of significant amounts of oxygenates (e.g., water, lower alcohols such as C.sub.2-C.sub.8 alcohols) in the feed stream. Accordingly, the present disclosure is uniquely suited to the production of fuels derived from bio-based alcohols, wherein olefins produced from such bio-based alcohols typically contain high levels of oxygenates.

The present invention relates to a catalyst composition comprising a modified crystalline aluminosilicate of the Framework Type FER having Si/Al framework molar ratio greater than 20 characterized in that in said modified crystalline aluminosilicate the ratio between the strong acid sites and the weak acid sites, S/W, is lower than 1.0 and having the extra framework aluminum (EFAL) content lowered to less than 10 wt % preferably 5 wt % even more preferably less than 2 wt % measured by 27 Al MAS NMR. The present invention further relates to a process for producing olefins from alcohols in presence of said catalyst composition.

Process for converting an olefin containing hydrocarbon feed into an oligomerization product or a hydrogenated oligomerization product, comprising contacting the feed in a reactor with an oligomerization catalyst under conditions suitable to oligomerize the olefin to obtain an oligomerization product and optionally hydrogenating the oligomerization product wherein the content of the at least one C.sub.4-, C.sub.5-, C.sub.6- or C.sub.7-cyclic olefin in the feed is controlled.

A method for purifying 1-hexene is disclosed. The method can include contacting a first stream containing 1-hexene and 2-ethyl-1-butene with an isomerization catalyst containing an comprising an alumina, silica-alumina, a zeolite, or an ion exchange resin, or any combinations thereof, under conditions sufficient to selectively isomerize at least a portion of 2-ethyl-1-butene into 3-methyl-2-pentene and form a second stream containing 1-hexene and 3-methyl-2-pentene, and separating the second stream into a third stream containing 1-hexene and a fourth stream containing 3-methyl-2-pentene.

According to an aspect of the present invention, provided is a zeolite catalyst having an MRE structure for hydro-isomerization. The zeolite catalyst has an adsorption volume ratio of lutidine to collidine measured by Fourier-transform infrared spectroscopy (FTIR) using lutidine and collidine as adsorbents of greater than 3 and less than or equal to 10. According to an aspect of the present invention, provided is a method of hydro-isomerization for a hydrocarbon feedstock, including subjecting the hydrocarbon feedstock to a hydro-isomerization reaction under conditions of a temperature of 200 C. to 500 C., a hydrogen pressure of 1 to 200 atmospheres, a liquid space velocity (LHSV) of 1.0 to 10.0 hr.sup.1, and the hydrogen/feedstock ratio of 45 to 1780 Nm.sup.3/m.sup.3 in the presence of the zeolite catalyst.

A catalyst for converting dimethyl ether into light olefins, including ethylene and propylene. The catalyst comprises a mixture of two zeolites, ZSM-5 and ZSM-35, intimately mixed and kept in close proximity in a porous extruded binder system. The resulting combination of zeolites demonstrates a synergistic effect with respect to the conversion of the dimethyl ether and has improved resistance to deactivation due to carbon and coke formation than the individual zeolites alone when operating in this reaction. The catalyst is used to produce ethylene and propylene from a feed mixture containing methanol, dimethyl ether and water.

A catalyst for converting dimethyl ether into light olefins, including ethylene and propylene. The catalyst comprises a mixture of two zeolites, ZSM-5 and ZSM-35, intimately mixed and kept in close proximity in a porous extruded binder system. The resulting combination of zeolites demonstrates a synergistic effect with respect to the conversion of the dimethyl ether and has improved resistance to deactivation due to carbon and coke formation than the individual zeolites alone when operating in this reaction. The catalyst is used to produce ethylene and propylene from a feed mixture containing methanol, dimethyl ether and water.

The present invention is a process for dehydrating an alcohol to prepare a corresponding olefin, comprising: (a) providing a composition (A) comprising at least an alcohol having at least 2 carbon atoms, optionally water, optionally an inert component, in a dehydration unit, (b) placing the composition (A) into contact with an acidic catalyst in a reaction zone of said dehydration unit at conditions effective to dehydrate at least a portion of the alcohol to make a corresponding olefin, (c) recovering from said dehydration unit an effluent (B) comprising: at least an olefin, water, undesired by-products including aldehydes and light products, optionally unconverted alcohol(s), optionally the inert component,
wherein, said composition (A)providing step (a) comprises adding an effective amount of one or more sulfur containing compound capable to reduce the undesired by-products by comparison with a non introduction of such sulfur containing compound. The component introduced at step (a) can be chosen from the group consisting of thiols, sulfides, disulfides.

A layered-structure, multifunctional monolith catalyst is provided. The multifunctional monolith catalyst includes a monolithic substrate. A first layer is coated on a surface of the substrate. The first layer includes a first catalyst. A second layer is formed on top of the first layer. The second layer includes a second catalyst, and the second layer is porous. Layering of the first and second catalysts reduces degradation of one or both of the first and second catalysts, and increases a yield of the reaction catalyzed by the second catalyst. A method of converting carbon dioxide to dimethyl ether using the multifunctional monolith catalyst is also provided.