The present invention relates to a process for the dehydration of at least one oxygenated compound, preferably selected from saturated alcohols, unsaturated alcohols, diols, ethers, in the presence of at least one dehydration catalyst selected from cerium oxide (CeO.sub.2), aluminium oxide (γ-Al.sub.2O.sub.3), aluminium silicate, silica-aluminas (SiO.sub.2-Al.sub.2O.sub.3), aluminas, zeolites, sulfonated resins, ion-exchange resins, metal oxides (for example, lanthanum oxide, zirconium oxide, tungsten oxide, thallium oxide, magnesium oxide, zinc oxide); of at least one basic agent selected from ammonia (NH.sub.3), or from inorganic or organic compounds containing nitrogen capable of developing ammonia (NH.sub.3) during said dehydration process; and, optionally, of silica (SiO.sub.2), or of at least one catalyst for the dissociation of ammonia (NH.sub.3) selected from catalysts comprising silica (SiO.sub.2), preferably of silica (SiO.sub.2).

The present invention relates to a process for the dehydration of at least one oxygenated compound, preferably selected from saturated alcohols, unsaturated alcohols, diols, ethers, in the presence of at least one dehydration catalyst selected from cerium oxide (CeO.sub.2), aluminium oxide (γ-Al.sub.2O.sub.3), aluminium silicate, silica-aluminas (SiO.sub.2-Al.sub.2O.sub.3), aluminas, zeolites, sulfonated resins, ion-exchange resins, metal oxides (for example, lanthanum oxide, zirconium oxide, tungsten oxide, thallium oxide, magnesium oxide, zinc oxide); of at least one basic agent selected from ammonia (NH.sub.3), or from inorganic or organic compounds containing nitrogen capable of developing ammonia (NH.sub.3) during said dehydration process; and, optionally, of silica (SiO.sub.2), or of at least one catalyst for the dissociation of ammonia (NH.sub.3) selected from catalysts comprising silica (SiO.sub.2), preferably of silica (SiO.sub.2).

Process for the production of a diene, preferably a conjugated diene, more preferably 1,3-butadiene, comprising the dehydration of at least one alkenol in the presence of at least one catalytic material comprising at least one acid catalyst based on silica (SiO.sub.2) and alumina (AI.sub.2O.sub.3), preferably a silica-alumina (SiO.sub.2-AI.sub.2O.sub.3), said catalyst having a content of alumina (AI.sub.2O.sub.3) lower than or equal to 12% by weight, preferably ranging from 0.1% by weight to 10% by weight, with respect to the total weight of the catalyst. Preferably, said alkenol can be obtained directly from biosynthesis processes, or through the catalytic dehydration of at least one diol, preferably a butanediol, more preferably 1,3-butanediol, even more preferably bio-1,3-butanediol, deriving from biosynthesis processes. Preferably, said 1,3-butadiene is bio-1,3-butadiene.

Process for the production of a diene, preferably a conjugated diene, more preferably 1,3-butadiene, comprising the dehydration of at least one alkenol in the presence of at least one catalytic material comprising at least one acid catalyst based on silica (SiO.sub.2) and alumina (AI.sub.2O.sub.3), preferably a silica-alumina (SiO.sub.2-AI.sub.2O.sub.3), said catalyst having a content of alumina (AI.sub.2O.sub.3) lower than or equal to 12% by weight, preferably ranging from 0.1% by weight to 10% by weight, with respect to the total weight of the catalyst. Preferably, said alkenol can be obtained directly from biosynthesis processes, or through the catalytic dehydration of at least one diol, preferably a butanediol, more preferably 1,3-butanediol, even more preferably bio-1,3-butanediol, deriving from biosynthesis processes. Preferably, said 1,3-butadiene is bio-1,3-butadiene.

There is provided a method for synthesizing an alkenoic acid, in particular acrylic acid comprising the step of oxidizing an alkenyl alcohol in the presence of a metal oxide catalyst to form the alkenoic acid. The invention further provides a step of deoxydehydrating a polyol, including glycerol to obtain said alkenyl alcohol including an allyl alcohol.

There is provided a method for synthesizing an alkenoic acid, in particular acrylic acid comprising the step of oxidizing an alkenyl alcohol in the presence of a metal oxide catalyst to form the alkenoic acid. The invention further provides a step of deoxydehydrating a polyol, including glycerol to obtain said alkenyl alcohol including an allyl alcohol.

The present invention relates to a process for producing a diene, preferably a conjugated diene, more preferably 1,3-butadiene, comprising the dehydration of at least one alkenol having a number of carbon atoms greater than or equal to 4, in the presence of a catalytic material comprising at least one crystalline metalosilicate in acid form, preferably a macroporous zeolite, more preferably a zeolite with a FAU, BEA or MTW structure. Preferably, said alkenol having a number of carbon atoms greater than or equal to 4 may be obbtained directly through biosynthetic processes, or through catalytic dehydration processes of at least one diol. When said alkenol is a butenol, said 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 said alkenol is 1,3-butanediol, or bio-1,3-butanediol, the diene obtained with the process according to the present invention is, respectively, 1,3-butadiene, or bio-1,3-butadiene.

The present invention relates to a process for producing a diene, preferably a conjugated diene, more preferably 1,3-butadiene, comprising the dehydration of at least one alkenol having a number of carbon atoms greater than or equal to 4, in the presence of a catalytic material comprising at least one crystalline metalosilicate in acid form, preferably a macroporous zeolite, more preferably a zeolite with a FAU, BEA or MTW structure. Preferably, said alkenol having a number of carbon atoms greater than or equal to 4 may be obbtained directly through biosynthetic processes, or through catalytic dehydration processes of at least one diol. When said alkenol is a butenol, said 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 said alkenol is 1,3-butanediol, or bio-1,3-butanediol, the diene obtained with the process according to the present invention 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.

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.