A high-purity 1,3-butylene glycol product that is colorless and odorless (or almost colorless and odorless), unlikely to cause coloration and odor over time, and/or unlikely to cause an acid concentration increase over time when the product is left in a state containing water is provided. A 1,3-butylene glycol product containing 1,3-butylene glycol, wherein, after the 1,3-butylene glycol product has been kept at 180° C. for 3 hours in air atmosphere, at least one of contents of compounds represented by the following Formula (A) or (B) is less than 8 ppm. In the following formula, R.sup.1 to R.sup.4 are the same as or different from each other, and each of R.sup.1 to R.sup.4 is a hydrogen atom, an alkyl group which has from 1 to 4 carbon atoms and may be substituted with a hydroxy group, or an alkenyl group which has from 2 to 4 carbon atoms and may be substituted with a hydroxy group.

A catalyst having coke wherein the coke, upon analysis by infrared spectroscopy in diffuse reflection, has at least two peaks at a wavelength between 1450 cm.sup.−1 and 1700 cm.sup.−1.

The aforesaid catalyst having coke can be advantageously used in a process for the production of a diene, preferably a conjugated diene, more preferably 1,3-butadiene, said process having the dehydration of at least one alkenol having a number of carbon atoms greater than or equal to 4.

Preferably, the alkenol having a number of carbon atoms greater than or equal to 4 can be obtained directly from biosynthetic processes, or through catalytic dehydration processes of at least one diol.

When the alkenol is a butenol, the diol is preferably a butanediol, more preferably 1,3-butanediol, even more preferably bio-1,3-butanediol, i.e. 1,3-butanediol deriving from biosynthetic processes.

When the diol is 1,3-butanediol, or bio-1,3-butanediol, the diene obtained with the process is, respectively, 1,3-butadiene, or bio-1,3-butadiene.

A catalyst having coke wherein the coke, upon analysis by infrared spectroscopy in diffuse reflection, has at least two peaks at a wavelength between 1450 cm.sup.−1 and 1700 cm.sup.−1.

The aforesaid catalyst having coke can be advantageously used in a process for the production of a diene, preferably a conjugated diene, more preferably 1,3-butadiene, said process having the dehydration of at least one alkenol having a number of carbon atoms greater than or equal to 4.

Preferably, the alkenol having a number of carbon atoms greater than or equal to 4 can be obtained directly from biosynthetic processes, or through catalytic dehydration processes of at least one diol.

When the alkenol is a butenol, the diol is preferably a butanediol, more preferably 1,3-butanediol, even more preferably bio-1,3-butanediol, i.e. 1,3-butanediol deriving from biosynthetic processes.

When the diol is 1,3-butanediol, or bio-1,3-butanediol, the diene obtained with the process is, respectively, 1,3-butadiene, or bio-1,3-butadiene.

The present disclosure provides methods for producing a regenerated hydrogenation catalyst from a fouled hydrogenation catalyst having a total surface area and at least one associated impurity. The method can include maintaining contact between the fouled hydrogenation catalyst and a flushing medium that comprises water, oxygen, and an inert or diluent gas at a regeneration temperature and a regeneration pressure sufficient to remove at least a portion of the at least one impurity from the hydrogenation catalyst to produce the regenerated hydrogenation catalyst, where the regenerated hydrogenation catalyst is characterized as retaining at least 70% of the activity of the hydrogenation catalyst.

The present disclosure provides methods for producing a regenerated hydrogenation catalyst from a fouled hydrogenation catalyst having a total surface area and at least one associated impurity. The method can include maintaining contact between the fouled hydrogenation catalyst and a flushing medium that comprises water, oxygen, and an inert or diluent gas at a regeneration temperature and a regeneration pressure sufficient to remove at least a portion of the at least one impurity from the hydrogenation catalyst to produce the regenerated hydrogenation catalyst, where the regenerated hydrogenation catalyst is characterized as retaining at least 70% of the activity of the hydrogenation catalyst.

The present invention relates to the use of a catalyst made of rhenium oxide supported by cerium oxide, with formula ReO.sub.x/CeO.sub.2 (I), for catalyzing the deoxydehydration of glycerol to allyl alcohol, the reaction being carried out under heterogeneous conditions in the presence of at least one aliphatic alcohol; and to a method for producing allyl alcohol from glycerol in the presence of the catalyst.

The present invention relates to the use of a catalyst made of rhenium oxide supported by cerium oxide, with formula ReO.sub.x/CeO.sub.2 (I), for catalyzing the deoxydehydration of glycerol to allyl alcohol, the reaction being carried out under heterogeneous conditions in the presence of at least one aliphatic alcohol; and to a method for producing allyl alcohol from glycerol in the presence of the catalyst.

The present invention relates to the use of a catalyst made of rhenium oxide supported by cerium oxide, with formula ReO.sub.x/CeO.sub.2 (I), for catalyzing the deoxydehydration of glycerol to allyl alcohol, the reaction being carried out under heterogeneous conditions in the presence of at least one aliphatic alcohol; and to a method for producing allyl alcohol from glycerol in the presence of the catalyst.

The presently claimed invention relates to a process for the recovery of 3-methyl-3-buten- -ol from a stream comprising (Z)-3-methylpent-2-ene-1,5-diol, (E)-3-methylpent-2-ene-,5-diol and 3-methylenepentane-1,5-diol by treating the stream with isobutene and water.

The presently claimed invention relates to a process for the recovery of 3-methyl-3-buten- -ol from a stream comprising (Z)-3-methylpent-2-ene-1,5-diol, (E)-3-methylpent-2-ene-,5-diol and 3-methylenepentane-1,5-diol by treating the stream with isobutene and water.