The disclosure relates to a zeolite catalyst for side-chain alkylation of toluene with methanol, including a zeolite NaX and Na.sub.3PO.sub.4 or Na.sub.2HPO.sub.4 supported on the zeolite NaX. The zeolite catalyst can be effective for catalyzing the side-chain alkylation of toluene with methanol. The disclosure also relates to a process for preparing a zeolite catalyst for side-chain alkylation of toluene with methanol, which is simple, practical and cheap in cost.

A process for treating mixtures containing polyalkylaromatic hydrocarbons, intended for transalkylation processes, includes a mild reduction with hydrogen in the presence of a suitable hydrogenation catalyst. The process also relates to a transalkylation process of polyalkylaromatic hydrocarbons having the treatment.

A process for treating mixtures containing polyalkylaromatic hydrocarbons, intended for transalkylation processes, includes a mild reduction with hydrogen in the presence of a suitable hydrogenation catalyst. The process also relates to a transalkylation process of polyalkylaromatic hydrocarbons having the treatment.

The present invention relates to the field of alkylation catalysts, and disclosed are a composite ZSM-5 molecular sieve, a preparation method therefor, a catalyst and an application thereof. A single crystal of the composite ZSM-5 molecular sieve comprises a main crystal and a twin crystal; the main crystal and the twin crystal are both ZSM-5 crystals; a crystal plane [010] of the main crystal is covered by a crystal plane [100] of the twin crystal; and the ratio of the number of sinusoidal pore openings to the number of straight pore openings on the outer surface of the single crystal of the composite ZSM-5 molecular sieve is (0.7-10:1), and the molar ratio Y1 of an Si element to an Al element within 10 nm of the surface is (300-2000):1. The single crystal of the composite ZSM-5 molecular sieve of the present invention has a large ratio of the number of sinusoidal pore openings to the number of straight pore openings, and is aluminum-poor on the surface and aluminum-rich on the inside. When applied to the toluene methanol alkylation reaction to prepare p-xylene, the selectivity of p-xylene may be greatly improved.

This disclosure provides improved processes for converting benzene/toluene via methylation with methanol/dimethyl ether for producing, e.g., p-xylene. In an embodiment, a process comprises contacting a methylation agent feed with an aromatic hydrocarbon feed in the presence of a methylation catalyst in a methylation reactor at increased pressure. Reduced methylation catalyst deactivation can be achieved with increased pressure in the methylation reactor.

This disclosure provides improved processes for converting benzene/toluene via methylation with methanol/dimethyl ether for producing, e.g., p-xylene. In an embodiment, a process comprises contacting a methylation agent feed with an aromatic hydrocarbon feed in the presence of a methylation catalyst in a methylation reactor at increased pressure. Reduced methylation catalyst deactivation can be achieved with increased pressure in the methylation reactor.

The present invention relates to a plant and a process for producing propylene at least one oxygenate, comprising a reactor for converting the reactant mixture into a product mixture which comprises propylene and also aliphatic and aromatic C.sub.5+ hydrocarbons, at least one distillation column for removing a C.sub.5+ stream, the C.sub.5+ stream comprising at least 90 wt % of the aliphatic and aromatic C.sub.5+ hydrocarbons of the product mixture, an extractive distillation column for separating the C.sub.5+ stream into an aromatics stream and an aliphatics stream, the aliphatics stream comprising at least 90 wt % of the aliphatics of the C.sub.5+ stream, and the aromatics stream comprising at least 90 wt % of the aromatics of the C.sub.5+ stream, and an aliphatics recycle line for at least partial recycling of the aliphatics stream to the reactor. According to the invention, an aromatics recycle line is provided which returns the aromatics stream at least partially as extractant into the extractive distillation column.

The present invention relates to a plant and a process for producing propylene at least one oxygenate, comprising a reactor for converting the reactant mixture into a product mixture which comprises propylene and also aliphatic and aromatic C.sub.5+ hydrocarbons, at least one distillation column for removing a C.sub.5+ stream, the C.sub.5+ stream comprising at least 90 wt % of the aliphatic and aromatic C.sub.5+ hydrocarbons of the product mixture, an extractive distillation column for separating the C.sub.5+ stream into an aromatics stream and an aliphatics stream, the aliphatics stream comprising at least 90 wt % of the aliphatics of the C.sub.5+ stream, and the aromatics stream comprising at least 90 wt % of the aromatics of the C.sub.5+ stream, and an aliphatics recycle line for at least partial recycling of the aliphatics stream to the reactor. According to the invention, an aromatics recycle line is provided which returns the aromatics stream at least partially as extractant into the extractive distillation column.

In this invention, a portion of the products from a pyrolysis reactor are reacted in a process to form one or more chemical intermediates.

A process is described for producing paraxylene, in which an aromatic hydrocarbon feedstock comprising benzene and/or toluene is contacted with an alkylating reagent comprising methanol and/or dimethyl ether in an alkylation reaction zone under alkylation conditions in the presence of an alkylation catalyst to produce an alkylated aromatic product comprising xylenes. The alkylation catalyst comprises a molecular sieve having a Constraint Index≤5, and the alkylation conditions comprise a temperature less than 500° C. Paraxylene may then be recovered from the alkylated aromatic product.