The present invention describes compositions comprising at least one compound chosen from hydroquinone and catechol, characterised in that it further comprises between 0.1 and 10,000 ppm of at least one compound chosen from 2-(alkoxy)phenol, 4-(alkoxy)phenol, 2-(alkyl)phenol, 4-(alkyl)phenol, (alkyl)catechol and (alkyl)hydroquinone. Another aspect of this invention concerns a method for preparing a composition comprising at least one compound chosen from hydroquinone and catechol according to the invention, characterised in that it comprises a step (a) of reacting the phenol with hydrogen peroxide in the presence of a catalyst, in a solvent comprising an alcohol.

Alkyl-demethylation of C2+-hydrocarbyl substituted aromatic hydrocarbons can be utilized to treat one or more of a heavy naphtha reformate stream, a hydrotreated SCN stream, a C8 aromatic hydrocarbon isomerization feed stream, a C9+ aromatic hydrocarbon transalkylation feed stream, and similar hydrocarbon streams to produce additional quantity of xylene products.

Alkyl-demethylation of C2+-hydrocarbyl substituted aromatic hydrocarbons can be utilized to treat one or more of a heavy naphtha reformate stream, a hydrotreated SCN stream, a C8 aromatic hydrocarbon isomerization feed stream, a C9+ aromatic hydrocarbon transalkylation feed stream, and similar hydrocarbon streams to produce additional quantity of xylene products.

A method of decomposing a phenol by-product produced in a phenol preparation process, in which acetophenone separated from a distillation column is mixed with tar separated and collected in a decomposition reactor, thereby significantly decreasing viscosity of tar. The decomposition method according to the present invention allows tar to have sufficient viscosity for flowability even at room temperature, whereby transfer and storage of tar may be more smoothly done without using any heating device for transfer of tar.

A method of decomposing a phenol by-product produced in a phenol preparation process, in which acetophenone separated from a distillation column is mixed with tar separated and collected in a decomposition reactor, thereby significantly decreasing viscosity of tar. The decomposition method according to the present invention allows tar to have sufficient viscosity for flowability even at room temperature, whereby transfer and storage of tar may be more smoothly done without using any heating device for transfer of tar.

A method for decomposing a phenolic by-product generated in a phenol preparation process, the method including: adding a phenolic by-product stream, a decomposition apparatus side discharge stream, and process water to a mixing apparatus and mixing the phenolic by-product stream, the decomposition apparatus side discharge stream, and the process water; adding a mixing apparatus discharge stream discharged from the mixing apparatus to a phase separation apparatus and phase-separating the mixing apparatus discharge stream into an oil phase and an aqueous phase; feeding an oil phase stream discharged from the phase-separation apparatus and discharged to a decomposition apparatus and decomposing the oil phase stream; and circulating the decomposition apparatus side discharge stream discharged from the decomposition apparatus to the mixing apparatus.

A method for decomposing a phenolic by-product generated in a phenol preparation process, the method including: adding a phenolic by-product stream, a decomposition apparatus side discharge stream, and process water to a mixing apparatus and mixing the phenolic by-product stream, the decomposition apparatus side discharge stream, and the process water; adding a mixing apparatus discharge stream discharged from the mixing apparatus to a phase separation apparatus and phase-separating the mixing apparatus discharge stream into an oil phase and an aqueous phase; feeding an oil phase stream discharged from the phase-separation apparatus and discharged to a decomposition apparatus and decomposing the oil phase stream; and circulating the decomposition apparatus side discharge stream discharged from the decomposition apparatus to the mixing apparatus.

Catalyst composition which comprises a first zeolite having a BEA* framework type and a second zeolite having a MOR framework type and a mesopore surface area of greater than 30 m.sup.2/g is disclosed. These catalyst compositions are used to remove catalyst poisons from untreated feed streams having one or more impurities which cause deactivation of the downstream catalysts employed in hydrocarbon conversion processes, such as those that produce mono-alkylated aromatic compounds.

Catalyst composition which comprises a first zeolite having a BEA* framework type and a second zeolite having a MOR framework type and a mesopore surface area of greater than 30 m.sup.2/g is disclosed. These catalyst compositions are used to remove catalyst poisons from untreated feed streams having one or more impurities which cause deactivation of the downstream catalysts employed in hydrocarbon conversion processes, such as those that produce mono-alkylated aromatic compounds.

Methods for removing impurities from a hydrocarbon stream using a guard bed material are disclosed. The guard bed material includes compositions which comprises a zeolite and a mesoporous support or binder. The zeolite has a Constraint Index of less than 3. The mesoporous support or binder comprises a mesoporous metal oxide having a particle diameter of greater than or equal to 20 μm at 50% of the cumulative pore size distribution (d.sub.50), a pore volume of less than 1 cc/g, and an alumina content of greater than 75%, by weight. Also disclosed are processes for producing mono-alkylated aromatic compounds (e.g., ethylbenzene or cumene) using impure feed streams that are treated by the disclosed methods to remove impurities which act as catalyst poisons to downstream alkylation and/or transalkylation catalysts.