Provided is a method for producing p-xylene, comprising: a provision step of providing a C4 fraction comprising at least isobutene as a product formed by fluidized catalytic cracking of a heavy oil fraction; a dimerization step of bringing a first raw material comprising the isobutene into contact with a dimerization catalyst to produce a C8 component comprising a dimer of isobutene; and a cyclization step of bringing a second raw material comprising the C8 component with a dehydrogenation catalyst to produce p-xylene through a cyclization/dehydrogenation reaction of the C8 component.

Provided is a process for hydrating and oligomerizing a hydrocarbon feed comprising mixed olefins, by contacting the feed with water and a catalyst in a fixed bed reactor, wherein the catalyst hydrates mixed olefins to mixed alcohols and oligomerizes mixed olefins into oligomers; introducing the resulting stream into a first separator that separates an organic phase from an aqueous phase; introducing the organic phase into a second separator that separates unreacted olefins from mixed alcohols/oligomers; introducing the aqueous phase into a third separator that separates an alcohol-water azeotrope from water; introducing the second stream into a fourth separator that separates sec-butyl alcohol to produce a third stream comprising mixed butanols and oligomers and an SBA stream; f) mixing the third stream and a first portion of the SBA stream to produce a final product stream; and g) recycling a second portion of the SBA stream to the second separator.

Provided is a process for hydrating and oligomerizing a hydrocarbon feed comprising mixed olefins, by contacting the feed with water and a catalyst in a fixed bed reactor, wherein the catalyst hydrates mixed olefins to mixed alcohols and oligomerizes mixed olefins into oligomers; introducing the resulting stream into a first separator that separates an organic phase from an aqueous phase; introducing the organic phase into a second separator that separates unreacted olefins from mixed alcohols/oligomers; introducing the aqueous phase into a third separator that separates an alcohol-water azeotrope from water; introducing the second stream into a fourth separator that separates sec-butyl alcohol to produce a third stream comprising mixed butanols and oligomers and an SBA stream; f) mixing the third stream and a first portion of the SBA stream to produce a final product stream; and g) recycling a second portion of the SBA stream to the second separator.

Processes and systems for C.sub.3+ monoolefin conversion. In some examples, the process can include reacting a first mixture that includes C.sub.3+ monoolefins and a first oxygenate to produce a first effluent that includes a first ether and <1 wt. % of any first di-C.sub.3+ olefin. A first product that includes the first ether and a first byproduct that includes at least a portion of any first di-C.sub.3+ olefin and unreacted C.sub.3+ monoolefins can be separated from the first effluent. A second olefin mixture, at least a portion of the first byproduct, and a second oxygenate can be combined to produce a second mixture. The second mixture can be reacted to produce a second effluent that includes a second ether and a second di-C.sub.3+ olefin. The reaction of the second mixture can produce a greater amount, on a mole basis, of the second di-C.sub.3+ olefin than the second ether.

Processes and systems for C.sub.3+ monoolefin conversion. In some examples, the process can include reacting a first mixture that includes C.sub.3+ monoolefins and a first oxygenate to produce a first effluent that includes a first ether and <1 wt. % of any first di-C.sub.3+ olefin. A first product that includes the first ether and a first byproduct that includes at least a portion of any first di-C.sub.3+ olefin and unreacted C.sub.3+ monoolefins can be separated from the first effluent. A second olefin mixture, at least a portion of the first byproduct, and a second oxygenate can be combined to produce a second mixture. The second mixture can be reacted to produce a second effluent that includes a second ether and a second di-C.sub.3+ olefin. The reaction of the second mixture can produce a greater amount, on a mole basis, of the second di-C.sub.3+ olefin than the second ether.

A method for producing p-xylene, comprising: a dimerization step of bringing a first raw material comprising isobutene into contact with a dimerization catalyst to generate C8 components comprising diisobutylene; a cyclization step of bringing a second raw material comprising the C8 components into contact with a dehydrogenation catalyst comprising Pt in the presence of hydrogen to obtain a reaction product comprising p-xylene; and a collection step of collecting p-xylene from the reaction product.

A method for producing p-xylene, comprising: a dimerization step of bringing a first raw material comprising isobutene into contact with a dimerization catalyst to generate C8 components comprising diisobutylene; a cyclization step of bringing a second raw material comprising the C8 components into contact with a dehydrogenation catalyst comprising Pt in the presence of hydrogen to obtain a reaction product comprising p-xylene; and a collection step of collecting p-xylene from the reaction product.

A method for producing p-xylene, comprising: a dimerization step of bringing a first raw material comprising isobutene into contact with a dimerization catalyst to generate C8 components comprising diisobutylene; a cyclization step of bringing a second raw material comprising the C8 components into contact with a dehydrogenation catalyst comprising Pt in the presence of water to obtain a reaction product comprising p-xylene; and a collection step of collecting p-xylene from the reaction product.

A method for producing p-xylene, comprising: a dimerization step of bringing a first raw material comprising isobutene into contact with a dimerization catalyst to generate C8 components comprising diisobutylene; a cyclization step of bringing a second raw material comprising the C8 components into contact with a dehydrogenation catalyst comprising Pt in the presence of water to obtain a reaction product comprising p-xylene; and a collection step of collecting p-xylene from the reaction product.

A process is described for the separation of C.sub.5 hydrocarbons present, in a quantity ranging from 0.2 to 20% by weight, in streams prevalently containing C.sub.4 products used for the production of high-octane hydrocarbon compounds, by the selective dimerization of isobutene, characterized in that the dimerization reaction is carried out in the presence of linear and branched alcohols and alkyl ethers in a quantity which is such as to have a molar ratio alcohols/alkyl ethers/isobutene in the feeding higher than 0.01.