This disclosure provides an improved process for converting benzene/toluene via methylation with methanol/dimethyl ether for producing, e.g., p-xylene, comprising separating and recycling dimethyl ether from the methylation reaction product mixture effluent to the methylation reactor. High selectivity toward p-xylene, among others, can be achieved.

This disclosure provides an improved process for converting benzene/toluene via methylation with methanol/dimethyl ether for producing, e.g., p-xylene, comprising separating and recycling dimethyl ether from the methylation reaction product mixture effluent to the methylation reactor. High selectivity toward p-xylene, among others, can be achieved.

The present invention relates to a method for preparing ZSM-5 zeolite. The present invention can provide a method for preparing ZSM-5 zeolite comprising the steps of: preparing a first solution in a solution state by heating a mixture comprising a silica source, an alumina source, a neutralizing agent and a crystalline ZSM-5 nucleus; preparing a reaction mother liquid by mixing a second solution comprising salts into the first solution; and continuously crystallizing by continuously supplying the reaction mother liquid to a hydrothermal synthesis reactor, wherein formula [1] below is satisfied.
0.20≤W.sub.a/W.sub.b≤0.40  Formula [1]

This disclosure provides improved processes for converting aromatic hydrocarbons, such as benzene/toluene, alkylation, transalkylation, or isomerization. In an embodiment, a process comprises utilizing a passivated reactor to reduce deactivation of a molecular sieve catalyst. Additional measures such as the use of an auxiliary catalyst and/or an elevated reactor pressure may be used to further reduce deactivation of the molecular sieve catalyst.

This disclosure provides improved processes for converting aromatic hydrocarbons, such as benzene/toluene, alkylation, transalkylation, or isomerization. In an embodiment, a process comprises utilizing a passivated reactor to reduce deactivation of a molecular sieve catalyst. Additional measures such as the use of an auxiliary catalyst and/or an elevated reactor pressure may be used to further reduce deactivation of the molecular sieve catalyst.

A process for producing a monoalkylated benzene comprises the step of contacting benzene with a mixture comprising dialkylated and trialkylated benzenes in the presence of a transalkylation catalyst composition under transalkylation conditions effective to convert at least part of the dialkylated and trialkylated benzene to monoalkylated benzene, wherein the transalkylation catalyst, composition comprises zeolite beta having an external surface in excess of 350 m2/g as determined by the t-plot method for nitrogen physisorption.

A process for producing a monoalkylated benzene comprises the step of contacting benzene with a mixture comprising dialkylated and trialkylated benzenes in the presence of a transalkylation catalyst composition under transalkylation conditions effective to convert at least part of the dialkylated and trialkylated benzene to monoalkylated benzene, wherein the transalkylation catalyst, composition comprises zeolite beta having an external surface in excess of 350 m2/g as determined by the t-plot method for nitrogen physisorption.

Systems and processes disclosed may be used to produce a high purity isobutane stream and a high purity 1-butene stream from mixed C4 streams having disparate starting compositions.

Methods of simultaneously converting butanes and methanol to olefins over Ti-containing zeolite catalysts are described. The exothermicity of the alcohols to olefins reaction is matched by endothermicity of dehydrogenation reaction of butane(s) to light olefins resulting in a thermo-neutral process. The Ti-containing zeolites provide excellent selectivity to light olefins as well as exceptionally high hydrothermal stability. The coupled reaction may advantageously be conducted in a staged reactor with methanol/DME conversion zones alternating with zones for butane(s) dehydrogenation. The resulting light olefins can then be reacted with iso-butane to produce high-octane alkylate. The net result is a highly efficient and low cost method for converting methanol and butanes to alkylate.

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.