A process for producing a diene, preferably a conjugated diene, more preferably 1,3-butadiene, includes the steps of dehydrating at least one alkenol in the presence of at least one catalytic material having at least one acid catalyst based on silica (SiO.sub.2) and alumina (Al.sub.2O.sub.3), preferably a silica-alumina (SiO.sub.2—Al.sub.2O.sub.3), the catalyst having an alumina content (Al.sub.2O.sub.3) lower than or equal to 12% by weight, preferably between 0.1% by weight and 10% by weight, with respect to the catalyst total weight. The alumina content is referred to the catalyst total weight without binder, and a pore modal diameter between 9 nm and 170 nm, preferably between 10 nm and 150 nm, still more preferably between 12 nm and 120 nm. Preferably, the alkenol is obtainable directly from biosynthetic processes, or catalytic dehydration processes of at least one diol, preferably a butanediol, more preferably 1,3-butanediol, still more preferably bio-1,3-butanediol, deriving from biosynthetic processes.

A process for producing a diene, preferably a conjugated diene, more preferably 1,3-butadiene, includes the steps of dehydrating at least one alkenol in the presence of at least one catalytic material having at least one acid catalyst based on silica (SiO.sub.2) and alumina (Al.sub.2O.sub.3), preferably a silica-alumina (SiO.sub.2—Al.sub.2O.sub.3), the catalyst having an alumina content (Al.sub.2O.sub.3) lower than or equal to 12% by weight, preferably between 0.1% by weight and 10% by weight, with respect to the catalyst total weight. The alumina content is referred to the catalyst total weight without binder, and a pore modal diameter between 9 nm and 170 nm, preferably between 10 nm and 150 nm, still more preferably between 12 nm and 120 nm. Preferably, the alkenol is obtainable directly from biosynthetic processes, or catalytic dehydration processes of at least one diol, preferably a butanediol, more preferably 1,3-butanediol, still more preferably bio-1,3-butanediol, deriving from biosynthetic processes.

The present invention relates to a process for the production of butadiene by condensation of ethanol using a catalyst containing sillica-supported elements from group 3A and group 4B of the periodic table. The catalyst of the present invention has high activity and selectivity to butadiene in the synthesis reaction of said olefin from ethanol.

The present invention relates to a process for the production of butadiene by condensation of ethanol using a catalyst containing sillica-supported elements from group 3A and group 4B of the periodic table. The catalyst of the present invention has high activity and selectivity to butadiene in the synthesis reaction of said olefin from ethanol.

Provided is a technique of producing isoprene from 3-methyl-1,3-butanediol or 1,3-butadiene from 1,3-butanediol by using a single catalyst. A catalyst produces a conjugated diene containing zirconium oxide and calcium oxide in order to produce isoprene by removing two water molecules from one 3-methyl-1,3-butanediol molecule or produce 1,3-butadiene by removing two water molecules from one 1,3-butanediol molecule. Furthermore, a method for producing a conjugated diene includes a step of obtaining a fluid containing a conjugated diene that is isoprene or 1,3-butadiene by bringing a fluid containing 3-methyl-1,3-butanediol or a fluid containing 1,3-butanediol into contact with the catalyst for producing a conjugated diene as a single catalyst so as to cause a dehydration reaction to proceed.

Provided is a technique of producing isoprene from 3-methyl-1,3-butanediol or 1,3-butadiene from 1,3-butanediol by using a single catalyst. A catalyst produces a conjugated diene containing zirconium oxide and calcium oxide in order to produce isoprene by removing two water molecules from one 3-methyl-1,3-butanediol molecule or produce 1,3-butadiene by removing two water molecules from one 1,3-butanediol molecule. Furthermore, a method for producing a conjugated diene includes a step of obtaining a fluid containing a conjugated diene that is isoprene or 1,3-butadiene by bringing a fluid containing 3-methyl-1,3-butanediol or a fluid containing 1,3-butanediol into contact with the catalyst for producing a conjugated diene as a single catalyst so as to cause a dehydration reaction to proceed.

A system and a method for separating C.sub.4 and recovering 1,3-butadiene are disclosed. The system includes a main washer column, a rectifier column for separating a bottom stream from the main washer column, an after washer column for purifying 1,3-butadiene from a side stream of the rectifier column comprising acetylenes and butadienes, a degasser column for separating a bottom stream from the rectifier column to produce a lean solvent stream. The lean solvent stream comprises primarily the solvent and about 8.3% water used in the main washer column and after washer column. A reboiler for the rectifier column includes one or more heat exchange units. At least one of the heat exchange units of the reboiler for the rectifier column uses steam as heating medium.

A system and a method for separating C.sub.4 and recovering 1,3-butadiene are disclosed. The system includes a main washer column, a rectifier column for separating a bottom stream from the main washer column, an after washer column for purifying 1,3-butadiene from a side stream of the rectifier column comprising acetylenes and butadienes, a degasser column for separating a bottom stream from the rectifier column to produce a lean solvent stream. The lean solvent stream comprises primarily the solvent and about 8.3% water used in the main washer column and after washer column. A reboiler for the rectifier column includes one or more heat exchange units. At least one of the heat exchange units of the reboiler for the rectifier column uses steam as heating medium.

A method of producing 1,3-butadiene including feeding oxygen and a feedstock gas containing n-butene into a reactor from the lower section of the reactor provided with a metal atom-containing catalyst, so that a product gas containing 1,3-butadiene is obtained through oxidative dehydrogenation of n-butene; cooling the product gas containing the 1,3-butadiene; and separating the 1,3-butadiene from the cooled product gas through selective absorption into an absorption solvent.

A method of producing 1,3-butadiene including feeding oxygen and a feedstock gas containing n-butene into a reactor from the lower section of the reactor provided with a metal atom-containing catalyst, so that a product gas containing 1,3-butadiene is obtained through oxidative dehydrogenation of n-butene; cooling the product gas containing the 1,3-butadiene; and separating the 1,3-butadiene from the cooled product gas through selective absorption into an absorption solvent.