A process for producing xylene from C.sub.9+ aromatic hydrocarbons comprises contacting a first feedstock comprising C.sub.9+ aromatic hydrocarbons with a first catalyst in the presence of hydrogen under effective vapor phase dealkylation conditions to dealkylate part of the C.sub.9+ aromatic hydrocarbons and produce a first product comprising benzene and unreacted C.sub.9+ aromatic hydrocarbons. A second feedstock comprising toluene is contacted with a second catalyst in the presence of hydrogen under effective vapor phase toluene disproportionation conditions to disproportionate at least part of the toluene and produce a second product comprising para-xylene. A third feedstock comprising C.sub.9+ aromatic hydrocarbons and benzene and/or toluene is contacted with a third catalyst in the presence of hydrogen under effective liquid phase C.sub.9+ transalkylation conditions to transalkylate at least part of the C.sub.9+ aromatic hydrocarbons and produce a third product comprising xylenes.

A process for producing xylene from C.sub.9+ aromatic hydrocarbons comprises contacting a first feedstock comprising C.sub.9+ aromatic hydrocarbons with a first catalyst in the presence of hydrogen under effective vapor phase dealkylation conditions to dealkylate part of the C.sub.9+ aromatic hydrocarbons and produce a first product comprising benzene and unreacted C.sub.9+ aromatic hydrocarbons. A second feedstock comprising toluene is contacted with a second catalyst in the presence of hydrogen under effective vapor phase toluene disproportionation conditions to disproportionate at least part of the toluene and produce a second product comprising para-xylene. A third feedstock comprising C.sub.9+ aromatic hydrocarbons and benzene and/or toluene is contacted with a third catalyst in the presence of hydrogen under effective liquid phase C.sub.9+ transalkylation conditions to transalkylate at least part of the C.sub.9+ aromatic hydrocarbons and produce a third product comprising xylenes.

Described are methods and compositions for inhibiting polymerization of a monomer (e.g., styrene) composition using a hydroxylated quinone antipolymerant. The hydroxylated quinone antipolymerant can be used with little or no nitroxyl group containing antipolymerant yet still provide excellent antipolymerant activity in a monomer-containing composition.

Described are methods and compositions for inhibiting polymerization of a monomer (e.g., styrene) composition using a hydroxylated quinone antipolymerant. The hydroxylated quinone antipolymerant can be used with little or no nitroxyl group containing antipolymerant yet still provide excellent antipolymerant activity in a monomer-containing composition.

Described are methods and compositions for inhibiting polymerization of a monomer (e.g., styrene) composition using a hydroxylated quinone antipolymerant. The hydroxylated quinone antipolymerant can be used with little or no nitroxyl group containing antipolymerant yet still provide excellent antipolymerant activity in a monomer-containing composition.

The present invention relates to a method for olefin oligomerization, and can provide a method for olefin oligomerization. The method includes the steps of: introducing an oligomerization transition metal catalyst, olefin monomers, and a solvent into a reactor and performing an olefin oligomerization reaction to produce an oligomer; introducing a catalyst deactivator to a reaction product of the oligomerization reaction to deactivate the catalyst, with the catalyst deactivator including at least one functional group containing at least one selected from the group including oxygen, phosphor, nitrogen, and sulfur and having a number average molecular weight of 400 or more; separating the oligomer through distillation in a distiller; and separating the catalyst deactivator through the bottom end of the distiller.

The present invention relates to a method for olefin oligomerization, and can provide a method for olefin oligomerization. The method includes the steps of: introducing an oligomerization transition metal catalyst, olefin monomers, and a solvent into a reactor and performing an olefin oligomerization reaction to produce an oligomer; introducing a catalyst deactivator to a reaction product of the oligomerization reaction to deactivate the catalyst, with the catalyst deactivator including at least one functional group containing at least one selected from the group including oxygen, phosphor, nitrogen, and sulfur and having a number average molecular weight of 400 or more; separating the oligomer through distillation in a distiller; and separating the catalyst deactivator through the bottom end of the distiller.

Described are compositions and methods for inhibiting polymerization of a monomer (e.g., styrene) composition a quinone methide polymerization retarder and an ammonium salt. In a mixture, the ammonium salt improves the efficacy of the quinone methide polymerization retarder and provides greater antipolymerant activity. In turn, the mixture reduces or prevents apparatus fouling and improves the purity of monomer streams.

Described are compositions and methods for inhibiting polymerization of a monomer (e.g., styrene) composition a quinone methide polymerization retarder and an ammonium salt. In a mixture, the ammonium salt improves the efficacy of the quinone methide polymerization retarder and provides greater antipolymerant activity. In turn, the mixture reduces or prevents apparatus fouling and improves the purity of monomer streams.

Provided herein are amphiphilic asphaltene ionic liquids and methods of making and using the amphiphilic asphaltene ionic liquids, e.g. as demulsifiers for petroleum crude oil-water emulsions.